[PATCH v2 00/12] libtracefs dynamic events support

[PATCH v2 00/12] libtracefs dynamic events support

[Tzvetomir Stoyanov (VMware)]

The libtracefs logic that works with ftrace dynamic events is unified and
capsulated into internal APIs. This change makes the code more consistent
and reusable. Also, adding future libtracefs support for uprobes and
eprobes dynamic events is simplified.
The existing library APIs for kprobes and synthetic events are reimplemented
using the new dynamic events helpers.

Suggested-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com>

v2 changes:
 - Removed triple pointer from the APIs.
 - Reimplement dynamic events parsing using strtok_r instead of strchr.
 - Coding style fixes.

Tzvetomir Stoyanov (VMware) (12):
  libtracefs: Add new internal APIs for dynamic events
  libtracefs: Rename tracefs_get_kprobes API
  libtracefs: New kprobes APIs
  libtracefs: Remove redundant kprobes APIs
  libtracefs: Reimplement tracefs_kprobes_get API
  libtracefs: Change tracefs_kprobe_info API
  libtracefs: Reimplement kprobe raw APIs
  libtracefs: Extend kprobes unit test
  libtracefs: Update kprobes man pages
  libtracefs: Rename tracefs_synth_init API
  libtracefs: Use the internal dynamic events API when creating
    synthetic events
  libtracefs: Document tracefs_dynevent_list_free() API

 Documentation/libtracefs-kprobes.txt | 131 ++++---
 Documentation/libtracefs-synth.txt   |  20 +-
 Documentation/libtracefs-synth2.txt  |  10 +-
 Documentation/libtracefs-utils.txt   |   6 +-
 Documentation/libtracefs.txt         |  12 +
 include/tracefs-local.h              |  35 ++
 include/tracefs.h                    |  38 +-
 src/Makefile                         |   1 +
 src/tracefs-dynevents.c              | 492 ++++++++++++++++++++++++++
 src/tracefs-hist.c                   | 110 +++---
 src/tracefs-kprobes.c                | 508 +++++++++++++--------------
 src/tracefs-sqlhist.c                |   6 +-
 utest/tracefs-utest.c                | 408 ++++++++++++---------
 13 files changed, 1187 insertions(+), 590 deletions(-)
 create mode 100644 src/tracefs-dynevents.c

-- 
2.31.1

[PATCH v2 01/12] libtracefs: Add new internal APIs for dynamic events

[Tzvetomir Stoyanov (VMware)]

Ftrace supports dynamic events, created by the user - kprobes, uprobes,
eprobes and synthetic events. There are two interfaces for managing
these events - new common "dynamic_events" file and event specific
"kprobe_events", "uprobe_events", "synthetic_events" files. The
configuration syntax for all dynamic events is almost the same.
To simplify support of dynamic events in thw tracefs library, a new
internal helper layer is implemented. It handles both configuration
interfaces - the common "dynamic_events" file is preferred, if
available. On the old kernels, where this file is missing, the event
specific files are used. The new helper layer can be used to create,
delete and get ftrace dynamic events form any type. Most of the APIs
are internal, not exposed to the library users. Only one API is exposed
publicly:
 tracefs_dynevent_list_free()
This new logic is designed to be used internally within the library,
from the APIs that implement kprobes, uprobes, eprobes and synthetic
events support.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/tracefs-local.h |  35 +++
 include/tracefs.h       |   3 +
 src/Makefile            |   1 +
 src/tracefs-dynevents.c | 492 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 531 insertions(+)
 create mode 100644 src/tracefs-dynevents.c

diff --git a/include/tracefs-local.h b/include/tracefs-local.h
index 684eccf..60440c6 100644
--- a/include/tracefs-local.h
+++ b/include/tracefs-local.h
@@ -15,6 +15,10 @@
 #define BUILD_BUG_ON(cond)			\
 	do { if (!(1/!(cond))) { } } while (0)
 
+#define SET_BIT(M, B)	do { (M) |= (1ULL << (B)); } while (0)
+#define TEST_BIT(M, B)	((M) & (1ULL<<(B)))
+#define CLEAR_BIT(M, B)	do { (M) &= ~(1ULL << (B)); } while (0)
+
 struct tracefs_options_mask {
 	unsigned long long	mask;
 };
@@ -94,4 +98,35 @@ int synth_add_start_field(struct tracefs_synth *synth,
 			  const char *start_field,
 			  const char *name,
 			  enum tracefs_hist_key_type type);
+
+/* Internal interface for ftrace dynamic events */
+enum trace_dynevent_type {
+	TRACE_DYNEVENT_KPROBE = 0,
+	TRACE_DYNEVENT_KRETPROBE,
+	TRACE_DYNEVENT_UPROBE,
+	TRACE_DYNEVENT_URETPROBE,
+	TRACE_DYNEVENT_EPROBE,
+	TRACE_DYNEVENT_SYNTH,
+	TRACE_DYNEVENT_MAX,
+};
+
+struct tracefs_dynevent {
+	char *trace_file;
+	char *prefix;
+	char *system;
+	char *event;
+	char *address;
+	char *format;
+	enum trace_dynevent_type type;
+};
+
+struct tracefs_dynevent *
+dynevent_alloc(enum trace_dynevent_type type, const char *system,
+	       const char *event, const char *address, const char *format);
+void dynevent_free(struct tracefs_dynevent *devent);
+int dynevent_create(struct tracefs_dynevent *devent);
+int dynevent_destroy(struct tracefs_dynevent *devent);
+struct tracefs_dynevent **dynevent_get_all(unsigned long type_mask, const char *system);
+int dynevent_get_count(unsigned long type_mask, const char *system);
+
 #endif /* _TRACE_FS_LOCAL_H */
diff --git a/include/tracefs.h b/include/tracefs.h
index a2cda30..ee167be 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -238,6 +238,9 @@ ssize_t tracefs_trace_pipe_stream(int fd, struct tracefs_instance *instance, int
 ssize_t tracefs_trace_pipe_print(struct tracefs_instance *instance, int flags);
 void tracefs_trace_pipe_stop(struct tracefs_instance *instance);
 
+struct tracefs_dynevent;
+void tracefs_dynevent_list_free(struct tracefs_dynevent **events);
+
 enum tracefs_kprobe_type {
 	TRACEFS_ALL_KPROBES,
 	TRACEFS_KPROBE,
diff --git a/src/Makefile b/src/Makefile
index 4e38d98..99cd7da 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -11,6 +11,7 @@ OBJS += tracefs-marker.o
 OBJS += tracefs-kprobes.o
 OBJS += tracefs-hist.o
 OBJS += tracefs-filter.o
+OBJS += tracefs-dynevents.o
 
 # Order matters for the the three below
 OBJS += sqlhist-lex.o
diff --git a/src/tracefs-dynevents.c b/src/tracefs-dynevents.c
new file mode 100644
index 0000000..0de4c49
--- /dev/null
+++ b/src/tracefs-dynevents.c
@@ -0,0 +1,492 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * Copyright (C) 2021 VMware Inc, Steven Rostedt <rostedt@goodmis.org>
+ *
+ * Updates:
+ * Copyright (C) 2021, VMware, Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
+ *
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <dirent.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+
+#include "tracefs.h"
+#include "tracefs-local.h"
+
+#define DYNEVENTS_EVENTS "dynamic_events"
+#define KPROBE_EVENTS "kprobe_events"
+#define UPROBE_EVENTS "uprobe_events"
+#define SYNTH_EVENTS "synthetic_events"
+#define DYNEVENTS_DEFAULT_GROUP "dynamic"
+
+struct dyn_events_desc;
+static int dyn_generic_parse(struct dyn_events_desc *,
+			     const char *, char *, struct tracefs_dynevent **);
+static int dyn_synth_parse(struct dyn_events_desc *,
+			   const char *, char *, struct tracefs_dynevent **);
+static int dyn_generic_del(struct dyn_events_desc *, struct tracefs_dynevent *);
+static int dyn_synth_del(struct dyn_events_desc *, struct tracefs_dynevent *);
+
+struct dyn_events_desc {
+	enum trace_dynevent_type type;
+	const char *file;
+	const char *prefix;
+	int (*dyn_events_del)(struct dyn_events_desc *desc, struct tracefs_dynevent *dyn);
+	int (*dyn_events_parse)(struct dyn_events_desc *desc, const char *group,
+				char *line, struct tracefs_dynevent **ret_dyn);
+} dynevents[] = {
+	{TRACE_DYNEVENT_KPROBE, NULL, "p", dyn_generic_del, dyn_generic_parse},
+	{TRACE_DYNEVENT_KRETPROBE, NULL, "r", dyn_generic_del, dyn_generic_parse},
+	{TRACE_DYNEVENT_UPROBE, NULL, "p", dyn_generic_del, dyn_generic_parse},
+	{TRACE_DYNEVENT_URETPROBE, NULL, "r", dyn_generic_del, dyn_generic_parse},
+	{TRACE_DYNEVENT_EPROBE, NULL, "e", dyn_generic_del, dyn_generic_parse},
+	{TRACE_DYNEVENT_SYNTH, NULL, "s", dyn_synth_del, dyn_synth_parse},
+};
+
+int dyn_generic_del(struct dyn_events_desc *desc, struct tracefs_dynevent *dyn)
+{
+	char *str;
+	int ret;
+
+	if (dyn->system)
+		ret = asprintf(&str, "-:%s/%s", dyn->system, dyn->event);
+	else
+		ret = asprintf(&str, "-:%s", dyn->event);
+
+	if (ret < 0)
+		return -1;
+
+	ret = tracefs_instance_file_append(NULL, desc->file, str);
+	free(str);
+
+	return ret < 0 ? ret : 0;
+}
+
+__hidden void dynevent_free(struct tracefs_dynevent *devent)
+{
+	if (!devent)
+		return;
+	free(devent->system);
+	free(devent->event);
+	free(devent->address);
+	free(devent->format);
+	free(devent->prefix);
+	free(devent->trace_file);
+	free(devent);
+}
+
+static int dyn_generic_parse(struct dyn_events_desc *desc, const char *group,
+			     char *line, struct tracefs_dynevent **ret_dyn)
+{
+	struct tracefs_dynevent *dyn;
+	char *format = NULL;
+	char *address;
+	char *system;
+	char *prefix;
+	char *event;
+	char *sav;
+
+	if (strncmp(line, desc->prefix, strlen(desc->prefix)))
+		return -1;
+
+	prefix = strtok_r(line, ":", &sav);
+	if (!prefix)
+		return -1;
+	system = strtok_r(NULL, "/", &sav);
+	if (!system)
+		return -1;
+	event = strtok_r(NULL, " ", &sav);
+	if (!event)
+		return -1;
+	address = strtok_r(NULL, " ", &sav);
+	if (!address)
+		address = event + strlen(event) + 1;
+	else
+		format = address + strlen(address) + 1;
+
+	/* KPROBEs and UPROBEs share the same prefix, check the format */
+	if (desc->type == TRACE_DYNEVENT_UPROBE || desc->type == TRACE_DYNEVENT_URETPROBE) {
+		if (!strchr(address, '/'))
+			return -1;
+	}
+	if (group && strcmp(group, system) != 0)
+		return -1;
+
+	if (!ret_dyn)
+		return 0;
+
+	dyn = calloc(1, sizeof(*dyn));
+	if (!dyn)
+		return -1;
+
+	dyn->type = desc->type;
+	dyn->trace_file = strdup(desc->file);
+	if (!dyn->trace_file)
+		goto error;
+	dyn->system = strdup(system);
+	if (!dyn->system)
+		goto error;
+	/* Prefix of KRETPROBE can contain MAXACTIVE integer */
+	dyn->prefix = strdup(prefix);
+	if (!dyn->prefix)
+		goto error;
+	dyn->event = strdup(event);
+	if (!dyn->event)
+		goto error;
+	if (desc->type == TRACE_DYNEVENT_SYNTH) {
+		/* Synthetic events have no address */
+		dyn->format = strdup(address);
+		if (!dyn->format)
+			goto error;
+	} else {
+		dyn->address = strdup(address);
+		if (!dyn->address)
+			goto error;
+		if (*format != '\0') {
+			dyn->format = strdup(format);
+			if (!dyn->format)
+				goto error;
+		}
+	}
+	*ret_dyn = dyn;
+	return 0;
+error:
+	dynevent_free(dyn);
+	return -1;
+}
+
+int dyn_synth_del(struct dyn_events_desc *desc, struct tracefs_dynevent *dyn)
+{
+	char *str;
+	int ret;
+
+	if (strcmp(desc->file, DYNEVENTS_EVENTS))
+		return dyn_generic_del(desc, dyn);
+
+	ret = asprintf(&str, "!%s", dyn->event);
+	if (ret < 0)
+		return -1;
+
+	ret = tracefs_instance_file_append(NULL, desc->file, str);
+	free(str);
+
+	return ret < 0 ? ret : 0;
+}
+
+static int dyn_synth_parse(struct dyn_events_desc *desc, const char *group,
+			   char *line, struct tracefs_dynevent **ret_dyn)
+{
+	struct tracefs_dynevent *dyn;
+	char *format;
+	char *event;
+	char *sav;
+
+	if (strcmp(desc->file, DYNEVENTS_EVENTS))
+		return dyn_generic_parse(desc, group, line, ret_dyn);
+
+	/* synthetic_events file has slightly different syntax */
+	event = strtok_r(line, " ", &sav);
+	if (!event)
+		return -1;
+
+	format = event + strlen(event) + 1;
+	if (*format == '\0')
+		return -1;
+	if (!ret_dyn)
+		return 0;
+
+	dyn = calloc(1, sizeof(*dyn));
+	if (!dyn)
+		return -1;
+	dyn->type = desc->type;
+	dyn->trace_file = strdup(desc->file);
+	if (!dyn->trace_file)
+		goto error;
+
+	dyn->event = strdup(event);
+	if (!dyn->event)
+		goto error;
+	dyn->format = strdup(format+1);
+	if (!dyn->format)
+		goto error;
+
+	*ret_dyn = dyn;
+	return 0;
+error:
+	dynevent_free(dyn);
+	return -1;
+}
+
+static void init_devent_desc(void)
+{
+	int i;
+
+	BUILD_BUG_ON(ARRAY_SIZE(dynevents) != TRACE_DYNEVENT_MAX);
+
+	/* Use  ftrace dynamic_events, if available */
+	if (tracefs_file_exists(NULL, DYNEVENTS_EVENTS)) {
+		for (i = 0; i < TRACE_DYNEVENT_MAX; i++)
+			dynevents[i].file = DYNEVENTS_EVENTS;
+		return;
+	}
+
+	if (tracefs_file_exists(NULL, KPROBE_EVENTS)) {
+		dynevents[TRACE_DYNEVENT_KPROBE].file = KPROBE_EVENTS;
+		dynevents[TRACE_DYNEVENT_KRETPROBE].file = KPROBE_EVENTS;
+	}
+	if (tracefs_file_exists(NULL, UPROBE_EVENTS)) {
+		dynevents[TRACE_DYNEVENT_UPROBE].file = UPROBE_EVENTS;
+		dynevents[TRACE_DYNEVENT_URETPROBE].file = UPROBE_EVENTS;
+	}
+	if (tracefs_file_exists(NULL, SYNTH_EVENTS)) {
+		dynevents[TRACE_DYNEVENT_SYNTH].file = SYNTH_EVENTS;
+		dynevents[TRACE_DYNEVENT_SYNTH].prefix = "";
+	}
+
+}
+
+static struct dyn_events_desc *get_devent_desc(enum trace_dynevent_type type)
+{
+	static bool init;
+
+	if (!init) {
+		init_devent_desc();
+		init = true;
+	}
+
+	return &dynevents[type];
+}
+
+__hidden struct tracefs_dynevent *
+dynevent_alloc(enum trace_dynevent_type type, const char *system,
+	       const char *event, const char *address, const char *format)
+{
+	struct tracefs_dynevent *devent;
+	struct dyn_events_desc *desc;
+
+	if (!event) {
+		errno = EINVAL;
+		return NULL;
+	}
+
+	desc = get_devent_desc(type);
+	if (!desc || !desc->file) {
+		errno = ENOTSUP;
+		return NULL;
+	}
+
+	devent = calloc(1, sizeof(*devent));
+	if (!devent)
+		return NULL;
+
+	devent->type = type;
+	devent->trace_file = strdup(desc->file);
+	if (!devent->trace_file)
+		goto err;
+
+	if (!system)
+		system = DYNEVENTS_DEFAULT_GROUP;
+	devent->system = strdup(system);
+	if (!devent->system)
+		goto err;
+
+	devent->event = strdup(event);
+	if (!devent->event)
+		goto err;
+
+	devent->prefix = strdup(desc->prefix);
+	if (!devent->prefix)
+		goto err;
+
+	if (address) {
+		devent->address = strdup(address);
+		if (!devent->address)
+			goto err;
+	}
+	if (format) {
+		devent->format = strdup(format);
+		if (!devent->format)
+			goto err;
+	}
+
+	return devent;
+err:
+	dynevent_free(devent);
+	return NULL;
+}
+
+__hidden int dynevent_create(struct tracefs_dynevent *devent)
+{
+	char *str;
+	int ret;
+
+	if (!devent)
+		return -1;
+
+	if (devent->system && devent->system[0])
+		ret = asprintf(&str, "%s%s%s/%s %s %s\n",
+				devent->prefix, strlen(devent->prefix) > 0 ? ":" : "",
+				devent->system, devent->event,
+				devent->address ? devent->address : "",
+				devent->format ? devent->format : "");
+	else
+		ret = asprintf(&str, "%s%s%s %s %s\n",
+				devent->prefix, strlen(devent->prefix) > 0 ? ":" : "",
+				devent->event,
+				devent->address ? devent->address : "",
+				devent->format ? devent->format : "");
+	if (ret < 0)
+		return -1;
+
+	ret = tracefs_instance_file_append(NULL, devent->trace_file, str);
+	free(str);
+
+	return ret < 0 ? ret : 0;
+}
+
+__hidden int dynevent_destroy(struct tracefs_dynevent *devent)
+{
+	struct dyn_events_desc *desc;
+
+	if (!devent)
+		return -1;
+
+	desc = get_devent_desc(devent->type);
+	if (!desc)
+		return -1;
+
+	return desc->dyn_events_del(desc, devent);
+}
+
+static int get_all_type(enum trace_dynevent_type type, const char *system,
+			struct tracefs_dynevent ***ret_all)
+{
+	struct dyn_events_desc *desc;
+	struct tracefs_dynevent *devent, **tmp, **all = NULL;
+	char *content;
+	int count = 0;
+	char *line;
+	char *next;
+	int ret;
+
+	desc = get_devent_desc(type);
+	if (!desc)
+		return -1;
+
+	content = tracefs_instance_file_read(NULL, desc->file, NULL);
+	if (!content)
+		return -1;
+
+	line = content;
+	do {
+		next = strchr(line, '\n');
+		if (next)
+			*next = '\0';
+		ret = desc->dyn_events_parse(desc, system, line, ret_all ? &devent : NULL);
+		if (!ret) {
+			if (ret_all) {
+				tmp = realloc(all, (count+1)*sizeof(struct tracefs_dynevent *));
+				if (!tmp)
+					goto error;
+				all = tmp;
+				all[count] = devent;
+			}
+			count++;
+		}
+		line = next + 1;
+	} while (next);
+
+	free(content);
+	if (ret_all)
+		*ret_all = all;
+	return count;
+
+error:
+	free(content);
+	free(all);
+	return -1;
+}
+
+/**
+ * tracefs_dynevent_list_free - Deletes an array of pointers to dynamic event contexts
+ * @events: An array of pointers to dynamic event contexts. The last element of the array
+ *	    must be a NULL pointer.
+ */
+void tracefs_dynevent_list_free(struct tracefs_dynevent **events)
+{
+	int i = 0;
+
+	if (!events)
+		return;
+
+	while (events[i])
+		dynevent_free(events[i++]);
+
+	free(events);
+}
+
+__hidden struct tracefs_dynevent **dynevent_get_all(unsigned long type_mask, const char *system)
+{
+	struct tracefs_dynevent **events, **tmp, **all_events = NULL;
+	int count, all = 0;
+	int i;
+
+	for (i = 0; i < TRACE_DYNEVENT_MAX; i++) {
+		if (!TEST_BIT(type_mask, i))
+			continue;
+
+		count = get_all_type(i, system, &events);
+		if (count > 0) {
+			tmp = realloc(all_events,
+				     (all + count)*sizeof(struct tracefs_dynevent *));
+			if (!tmp)
+				goto error;
+			all_events = tmp;
+			memcpy(all_events + all, events,
+			       count*sizeof(struct tracefs_dynevent *));
+			all += count;
+		}
+
+	}
+
+	/* Add a NULL pointer at the end */
+	if (all > 0) {
+		tmp = realloc(all_events,
+			     (all + 1)*sizeof(struct tracefs_dynevent *));
+		if (!tmp)
+			goto error;
+
+		all_events = tmp;
+		all_events[all] = NULL;
+	}
+
+	return all_events;
+
+error:
+	if (all_events) {
+		for (i = 0; i < all; i++)
+			free(all_events[i]);
+		free(all_events);
+	}
+	return NULL;
+}
+
+__hidden int dynevent_get_count(unsigned long type_mask, const char *system)
+{
+	int count, all = 0;
+	int i;
+
+	for (i = 0; i < TRACE_DYNEVENT_MAX; i++) {
+		if (!TEST_BIT(type_mask, i))
+			continue;
+		count = get_all_type(i, system, NULL);
+		if (count > 0)
+			all += count;
+	}
+
+	return all;
+}
-- 
2.31.1

Re: [PATCH v2 01/12] libtracefs: Add new internal APIs for dynamic events

[Yordan Karadzhov]

On 1.11.21 г. 11:08, Tzvetomir Stoyanov (VMware) wrote:
> Ftrace supports dynamic events, created by the user - kprobes, uprobes,
> eprobes and synthetic events. There are two interfaces for managing
> these events - new common "dynamic_events" file and event specific
> "kprobe_events", "uprobe_events", "synthetic_events" files. The
> configuration syntax for all dynamic events is almost the same.
> To simplify support of dynamic events in thw tracefs library, a new

thw -> the

> internal helper layer is implemented. It handles both configuration
> interfaces - the common "dynamic_events" file is preferred, if
> available. On the old kernels, where this file is missing, the event
> specific files are used. The new helper layer can be used to create,
> delete and get ftrace dynamic events form any type. Most of the APIs

form -> from

> are internal, not exposed to the library users. Only one API is exposed
> publicly:
>   tracefs_dynevent_list_free()
> This new logic is designed to be used internally within the library,
> from the APIs that implement kprobes, uprobes, eprobes and synthetic
> events support.
> 
> Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
> ---
>   include/tracefs-local.h |  35 +++
>   include/tracefs.h       |   3 +
>   src/Makefile            |   1 +
>   src/tracefs-dynevents.c | 492 ++++++++++++++++++++++++++++++++++++++++
>   4 files changed, 531 insertions(+)
>   create mode 100644 src/tracefs-dynevents.c
> 
> diff --git a/include/tracefs-local.h b/include/tracefs-local.h
> index 684eccf..60440c6 100644
> --- a/include/tracefs-local.h
> +++ b/include/tracefs-local.h
> @@ -15,6 +15,10 @@
>   #define BUILD_BUG_ON(cond)			\
>   	do { if (!(1/!(cond))) { } } while (0)
>   
> +#define SET_BIT(M, B)	do { (M) |= (1ULL << (B)); } while (0)
> +#define TEST_BIT(M, B)	((M) & (1ULL<<(B)))
> +#define CLEAR_BIT(M, B)	do { (M) &= ~(1ULL << (B)); } while (0)
> +
>   struct tracefs_options_mask {
>   	unsigned long long	mask;
>   };
> @@ -94,4 +98,35 @@ int synth_add_start_field(struct tracefs_synth *synth,
>   			  const char *start_field,
>   			  const char *name,
>   			  enum tracefs_hist_key_type type);
> +
> +/* Internal interface for ftrace dynamic events */
> +enum trace_dynevent_type {
> +	TRACE_DYNEVENT_KPROBE = 0,
> +	TRACE_DYNEVENT_KRETPROBE,
> +	TRACE_DYNEVENT_UPROBE,
> +	TRACE_DYNEVENT_URETPROBE,
> +	TRACE_DYNEVENT_EPROBE,
> +	TRACE_DYNEVENT_SYNTH,
> +	TRACE_DYNEVENT_MAX,
> +};
> +
> +struct tracefs_dynevent {
> +	char *trace_file;
> +	char *prefix;
> +	char *system;
> +	char *event;
> +	char *address;
> +	char *format;
> +	enum trace_dynevent_type type;
> +};
> +
> +struct tracefs_dynevent *
> +dynevent_alloc(enum trace_dynevent_type type, const char *system,
> +	       const char *event, const char *address, const char *format);
> +void dynevent_free(struct tracefs_dynevent *devent);
> +int dynevent_create(struct tracefs_dynevent *devent);
> +int dynevent_destroy(struct tracefs_dynevent *devent);
> +struct tracefs_dynevent **dynevent_get_all(unsigned long type_mask, const char *system);
> +int dynevent_get_count(unsigned long type_mask, const char *system);
> +
>   #endif /* _TRACE_FS_LOCAL_H */
> diff --git a/include/tracefs.h b/include/tracefs.h
> index a2cda30..ee167be 100644
> --- a/include/tracefs.h
> +++ b/include/tracefs.h
> @@ -238,6 +238,9 @@ ssize_t tracefs_trace_pipe_stream(int fd, struct tracefs_instance *instance, int
>   ssize_t tracefs_trace_pipe_print(struct tracefs_instance *instance, int flags);
>   void tracefs_trace_pipe_stop(struct tracefs_instance *instance);
>   
> +struct tracefs_dynevent;
> +void tracefs_dynevent_list_free(struct tracefs_dynevent **events);
> +
>   enum tracefs_kprobe_type {
>   	TRACEFS_ALL_KPROBES,
>   	TRACEFS_KPROBE,
> diff --git a/src/Makefile b/src/Makefile
> index 4e38d98..99cd7da 100644
> --- a/src/Makefile
> +++ b/src/Makefile
> @@ -11,6 +11,7 @@ OBJS += tracefs-marker.o
>   OBJS += tracefs-kprobes.o
>   OBJS += tracefs-hist.o
>   OBJS += tracefs-filter.o
> +OBJS += tracefs-dynevents.o
>   
>   # Order matters for the the three below
>   OBJS += sqlhist-lex.o
> diff --git a/src/tracefs-dynevents.c b/src/tracefs-dynevents.c
> new file mode 100644
> index 0000000..0de4c49
> --- /dev/null
> +++ b/src/tracefs-dynevents.c
> @@ -0,0 +1,492 @@
> +// SPDX-License-Identifier: LGPL-2.1
> +/*
> + * Copyright (C) 2021 VMware Inc, Steven Rostedt <rostedt@goodmis.org>
> + *
> + * Updates:
> + * Copyright (C) 2021, VMware, Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
> + *
> + */
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <dirent.h>
> +#include <unistd.h>
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <limits.h>
> +
> +#include "tracefs.h"
> +#include "tracefs-local.h"
> +
> +#define DYNEVENTS_EVENTS "dynamic_events"
> +#define KPROBE_EVENTS "kprobe_events"

A definition of KPROBE_EVENTS already exists in /utest/tracefs-utest.c and src/tracefs-kprobes.c

Isn't better to move the whole group of definitions of filenames to include/tracefs-local.h?

Thanks!
Yordan

> +#define UPROBE_EVENTS "uprobe_events"
> +#define SYNTH_EVENTS "synthetic_events"
> +#define DYNEVENTS_DEFAULT_GROUP "dynamic"
> +
> +struct dyn_events_desc;
> +static int dyn_generic_parse(struct dyn_events_desc *,
> +			     const char *, char *, struct tracefs_dynevent **);
> +static int dyn_synth_parse(struct dyn_events_desc *,
> +			   const char *, char *, struct tracefs_dynevent **);
> +static int dyn_generic_del(struct dyn_events_desc *, struct tracefs_dynevent *);
> +static int dyn_synth_del(struct dyn_events_desc *, struct tracefs_dynevent *);
> +
> +struct dyn_events_desc {
> +	enum trace_dynevent_type type;
> +	const char *file;
> +	const char *prefix;
> +	int (*dyn_events_del)(struct dyn_events_desc *desc, struct tracefs_dynevent *dyn);
> +	int (*dyn_events_parse)(struct dyn_events_desc *desc, const char *group,
> +				char *line, struct tracefs_dynevent **ret_dyn);
> +} dynevents[] = {
> +	{TRACE_DYNEVENT_KPROBE, NULL, "p", dyn_generic_del, dyn_generic_parse},
> +	{TRACE_DYNEVENT_KRETPROBE, NULL, "r", dyn_generic_del, dyn_generic_parse},
> +	{TRACE_DYNEVENT_UPROBE, NULL, "p", dyn_generic_del, dyn_generic_parse},
> +	{TRACE_DYNEVENT_URETPROBE, NULL, "r", dyn_generic_del, dyn_generic_parse},
> +	{TRACE_DYNEVENT_EPROBE, NULL, "e", dyn_generic_del, dyn_generic_parse},
> +	{TRACE_DYNEVENT_SYNTH, NULL, "s", dyn_synth_del, dyn_synth_parse},
> +};
> +
> +int dyn_generic_del(struct dyn_events_desc *desc, struct tracefs_dynevent *dyn)
> +{
> +	char *str;
> +	int ret;
> +
> +	if (dyn->system)
> +		ret = asprintf(&str, "-:%s/%s", dyn->system, dyn->event);
> +	else
> +		ret = asprintf(&str, "-:%s", dyn->event);
> +
> +	if (ret < 0)
> +		return -1;
> +
> +	ret = tracefs_instance_file_append(NULL, desc->file, str);
> +	free(str);
> +
> +	return ret < 0 ? ret : 0;
> +}
> +
> +__hidden void dynevent_free(struct tracefs_dynevent *devent)
> +{
> +	if (!devent)
> +		return;
> +	free(devent->system);
> +	free(devent->event);
> +	free(devent->address);
> +	free(devent->format);
> +	free(devent->prefix);
> +	free(devent->trace_file);
> +	free(devent);
> +}
> +
> +static int dyn_generic_parse(struct dyn_events_desc *desc, const char *group,
> +			     char *line, struct tracefs_dynevent **ret_dyn)
> +{
> +	struct tracefs_dynevent *dyn;
> +	char *format = NULL;
> +	char *address;
> +	char *system;
> +	char *prefix;
> +	char *event;
> +	char *sav;
> +
> +	if (strncmp(line, desc->prefix, strlen(desc->prefix)))
> +		return -1;
> +
> +	prefix = strtok_r(line, ":", &sav);
> +	if (!prefix)
> +		return -1;
> +	system = strtok_r(NULL, "/", &sav);
> +	if (!system)
> +		return -1;
> +	event = strtok_r(NULL, " ", &sav);
> +	if (!event)
> +		return -1;
> +	address = strtok_r(NULL, " ", &sav);
> +	if (!address)
> +		address = event + strlen(event) + 1;
> +	else
> +		format = address + strlen(address) + 1;
> +
> +	/* KPROBEs and UPROBEs share the same prefix, check the format */
> +	if (desc->type == TRACE_DYNEVENT_UPROBE || desc->type == TRACE_DYNEVENT_URETPROBE) {
> +		if (!strchr(address, '/'))
> +			return -1;
> +	}
> +	if (group && strcmp(group, system) != 0)
> +		return -1;
> +
> +	if (!ret_dyn)
> +		return 0;
> +
> +	dyn = calloc(1, sizeof(*dyn));
> +	if (!dyn)
> +		return -1;
> +
> +	dyn->type = desc->type;
> +	dyn->trace_file = strdup(desc->file);
> +	if (!dyn->trace_file)
> +		goto error;
> +	dyn->system = strdup(system);
> +	if (!dyn->system)
> +		goto error;
> +	/* Prefix of KRETPROBE can contain MAXACTIVE integer */
> +	dyn->prefix = strdup(prefix);
> +	if (!dyn->prefix)
> +		goto error;
> +	dyn->event = strdup(event);
> +	if (!dyn->event)
> +		goto error;
> +	if (desc->type == TRACE_DYNEVENT_SYNTH) {
> +		/* Synthetic events have no address */
> +		dyn->format = strdup(address);
> +		if (!dyn->format)
> +			goto error;
> +	} else {
> +		dyn->address = strdup(address);
> +		if (!dyn->address)
> +			goto error;
> +		if (*format != '\0') {
> +			dyn->format = strdup(format);
> +			if (!dyn->format)
> +				goto error;
> +		}
> +	}
> +	*ret_dyn = dyn;
> +	return 0;
> +error:
> +	dynevent_free(dyn);
> +	return -1;
> +}
> +
> +int dyn_synth_del(struct dyn_events_desc *desc, struct tracefs_dynevent *dyn)
> +{
> +	char *str;
> +	int ret;
> +
> +	if (strcmp(desc->file, DYNEVENTS_EVENTS))
> +		return dyn_generic_del(desc, dyn);
> +
> +	ret = asprintf(&str, "!%s", dyn->event);
> +	if (ret < 0)
> +		return -1;
> +
> +	ret = tracefs_instance_file_append(NULL, desc->file, str);
> +	free(str);
> +
> +	return ret < 0 ? ret : 0;
> +}
> +
> +static int dyn_synth_parse(struct dyn_events_desc *desc, const char *group,
> +			   char *line, struct tracefs_dynevent **ret_dyn)
> +{
> +	struct tracefs_dynevent *dyn;
> +	char *format;
> +	char *event;
> +	char *sav;
> +
> +	if (strcmp(desc->file, DYNEVENTS_EVENTS))
> +		return dyn_generic_parse(desc, group, line, ret_dyn);
> +
> +	/* synthetic_events file has slightly different syntax */
> +	event = strtok_r(line, " ", &sav);
> +	if (!event)
> +		return -1;
> +
> +	format = event + strlen(event) + 1;
> +	if (*format == '\0')
> +		return -1;
> +	if (!ret_dyn)
> +		return 0;
> +
> +	dyn = calloc(1, sizeof(*dyn));
> +	if (!dyn)
> +		return -1;
> +	dyn->type = desc->type;
> +	dyn->trace_file = strdup(desc->file);
> +	if (!dyn->trace_file)
> +		goto error;
> +
> +	dyn->event = strdup(event);
> +	if (!dyn->event)
> +		goto error;
> +	dyn->format = strdup(format+1);
> +	if (!dyn->format)
> +		goto error;
> +
> +	*ret_dyn = dyn;
> +	return 0;
> +error:
> +	dynevent_free(dyn);
> +	return -1;
> +}
> +
> +static void init_devent_desc(void)
> +{
> +	int i;
> +
> +	BUILD_BUG_ON(ARRAY_SIZE(dynevents) != TRACE_DYNEVENT_MAX);
> +
> +	/* Use  ftrace dynamic_events, if available */
> +	if (tracefs_file_exists(NULL, DYNEVENTS_EVENTS)) {
> +		for (i = 0; i < TRACE_DYNEVENT_MAX; i++)
> +			dynevents[i].file = DYNEVENTS_EVENTS;
> +		return;
> +	}
> +
> +	if (tracefs_file_exists(NULL, KPROBE_EVENTS)) {
> +		dynevents[TRACE_DYNEVENT_KPROBE].file = KPROBE_EVENTS;
> +		dynevents[TRACE_DYNEVENT_KRETPROBE].file = KPROBE_EVENTS;
> +	}
> +	if (tracefs_file_exists(NULL, UPROBE_EVENTS)) {
> +		dynevents[TRACE_DYNEVENT_UPROBE].file = UPROBE_EVENTS;
> +		dynevents[TRACE_DYNEVENT_URETPROBE].file = UPROBE_EVENTS;
> +	}
> +	if (tracefs_file_exists(NULL, SYNTH_EVENTS)) {
> +		dynevents[TRACE_DYNEVENT_SYNTH].file = SYNTH_EVENTS;
> +		dynevents[TRACE_DYNEVENT_SYNTH].prefix = "";
> +	}
> +
> +}
> +
> +static struct dyn_events_desc *get_devent_desc(enum trace_dynevent_type type)
> +{
> +	static bool init;
> +
> +	if (!init) {
> +		init_devent_desc();
> +		init = true;
> +	}
> +
> +	return &dynevents[type];
> +}
> +
> +__hidden struct tracefs_dynevent *
> +dynevent_alloc(enum trace_dynevent_type type, const char *system,
> +	       const char *event, const char *address, const char *format)
> +{
> +	struct tracefs_dynevent *devent;
> +	struct dyn_events_desc *desc;
> +
> +	if (!event) {
> +		errno = EINVAL;
> +		return NULL;
> +	}
> +
> +	desc = get_devent_desc(type);
> +	if (!desc || !desc->file) {
> +		errno = ENOTSUP;
> +		return NULL;
> +	}
> +
> +	devent = calloc(1, sizeof(*devent));
> +	if (!devent)
> +		return NULL;
> +
> +	devent->type = type;
> +	devent->trace_file = strdup(desc->file);
> +	if (!devent->trace_file)
> +		goto err;
> +
> +	if (!system)
> +		system = DYNEVENTS_DEFAULT_GROUP;
> +	devent->system = strdup(system);
> +	if (!devent->system)
> +		goto err;
> +
> +	devent->event = strdup(event);
> +	if (!devent->event)
> +		goto err;
> +
> +	devent->prefix = strdup(desc->prefix);
> +	if (!devent->prefix)
> +		goto err;
> +
> +	if (address) {
> +		devent->address = strdup(address);
> +		if (!devent->address)
> +			goto err;
> +	}
> +	if (format) {
> +		devent->format = strdup(format);
> +		if (!devent->format)
> +			goto err;
> +	}
> +
> +	return devent;
> +err:
> +	dynevent_free(devent);
> +	return NULL;
> +}
> +
> +__hidden int dynevent_create(struct tracefs_dynevent *devent)
> +{
> +	char *str;
> +	int ret;
> +
> +	if (!devent)
> +		return -1;
> +
> +	if (devent->system && devent->system[0])
> +		ret = asprintf(&str, "%s%s%s/%s %s %s\n",
> +				devent->prefix, strlen(devent->prefix) > 0 ? ":" : "",
> +				devent->system, devent->event,
> +				devent->address ? devent->address : "",
> +				devent->format ? devent->format : "");
> +	else
> +		ret = asprintf(&str, "%s%s%s %s %s\n",
> +				devent->prefix, strlen(devent->prefix) > 0 ? ":" : "",
> +				devent->event,
> +				devent->address ? devent->address : "",
> +				devent->format ? devent->format : "");
> +	if (ret < 0)
> +		return -1;
> +
> +	ret = tracefs_instance_file_append(NULL, devent->trace_file, str);
> +	free(str);
> +
> +	return ret < 0 ? ret : 0;
> +}
> +
> +__hidden int dynevent_destroy(struct tracefs_dynevent *devent)
> +{
> +	struct dyn_events_desc *desc;
> +
> +	if (!devent)
> +		return -1;
> +
> +	desc = get_devent_desc(devent->type);
> +	if (!desc)
> +		return -1;
> +
> +	return desc->dyn_events_del(desc, devent);
> +}
> +
> +static int get_all_type(enum trace_dynevent_type type, const char *system,
> +			struct tracefs_dynevent ***ret_all)
> +{
> +	struct dyn_events_desc *desc;
> +	struct tracefs_dynevent *devent, **tmp, **all = NULL;
> +	char *content;
> +	int count = 0;
> +	char *line;
> +	char *next;
> +	int ret;
> +
> +	desc = get_devent_desc(type);
> +	if (!desc)
> +		return -1;
> +
> +	content = tracefs_instance_file_read(NULL, desc->file, NULL);
> +	if (!content)
> +		return -1;
> +
> +	line = content;
> +	do {
> +		next = strchr(line, '\n');
> +		if (next)
> +			*next = '\0';
> +		ret = desc->dyn_events_parse(desc, system, line, ret_all ? &devent : NULL);
> +		if (!ret) {
> +			if (ret_all) {
> +				tmp = realloc(all, (count+1)*sizeof(struct tracefs_dynevent *));
> +				if (!tmp)
> +					goto error;
> +				all = tmp;
> +				all[count] = devent;
> +			}
> +			count++;
> +		}
> +		line = next + 1;
> +	} while (next);
> +
> +	free(content);
> +	if (ret_all)
> +		*ret_all = all;
> +	return count;
> +
> +error:
> +	free(content);
> +	free(all);
> +	return -1;
> +}
> +
> +/**
> + * tracefs_dynevent_list_free - Deletes an array of pointers to dynamic event contexts
> + * @events: An array of pointers to dynamic event contexts. The last element of the array
> + *	    must be a NULL pointer.
> + */
> +void tracefs_dynevent_list_free(struct tracefs_dynevent **events)
> +{
> +	int i = 0;
> +
> +	if (!events)
> +		return;
> +
> +	while (events[i])
> +		dynevent_free(events[i++]);
> +
> +	free(events);
> +}
> +
> +__hidden struct tracefs_dynevent **dynevent_get_all(unsigned long type_mask, const char *system)
> +{
> +	struct tracefs_dynevent **events, **tmp, **all_events = NULL;
> +	int count, all = 0;
> +	int i;
> +
> +	for (i = 0; i < TRACE_DYNEVENT_MAX; i++) {
> +		if (!TEST_BIT(type_mask, i))
> +			continue;
> +
> +		count = get_all_type(i, system, &events);
> +		if (count > 0) {
> +			tmp = realloc(all_events,
> +				     (all + count)*sizeof(struct tracefs_dynevent *));
> +			if (!tmp)
> +				goto error;
> +			all_events = tmp;
> +			memcpy(all_events + all, events,
> +			       count*sizeof(struct tracefs_dynevent *));
> +			all += count;
> +		}
> +
> +	}
> +
> +	/* Add a NULL pointer at the end */
> +	if (all > 0) {
> +		tmp = realloc(all_events,
> +			     (all + 1)*sizeof(struct tracefs_dynevent *));
> +		if (!tmp)
> +			goto error;
> +
> +		all_events = tmp;
> +		all_events[all] = NULL;
> +	}
> +
> +	return all_events;
> +
> +error:
> +	if (all_events) {
> +		for (i = 0; i < all; i++)
> +			free(all_events[i]);
> +		free(all_events);
> +	}
> +	return NULL;
> +}
> +
> +__hidden int dynevent_get_count(unsigned long type_mask, const char *system)
> +{
> +	int count, all = 0;
> +	int i;
> +
> +	for (i = 0; i < TRACE_DYNEVENT_MAX; i++) {
> +		if (!TEST_BIT(type_mask, i))
> +			continue;
> +		count = get_all_type(i, system, NULL);
> +		if (count > 0)
> +			all += count;
> +	}
> +
> +	return all;
> +}
> 

Re: [PATCH v2 01/12] libtracefs: Add new internal APIs for dynamic events

[Tzvetomir Stoyanov]

On Mon, Nov 1, 2021 at 7:06 PM Yordan Karadzhov <y.karadz@gmail.com> wrote:
>
>
[ ... ]
> > +
> > +#define DYNEVENTS_EVENTS "dynamic_events"
> > +#define KPROBE_EVENTS "kprobe_events"
>
> A definition of KPROBE_EVENTS already exists in /utest/tracefs-utest.c and src/tracefs-kprobes.c
>
> Isn't better to move the whole group of definitions of filenames to include/tracefs-local.h?

The unit test should use only the official library API, defined in
tracefs.h. We could move these defines in the official API header, but
I think these should be internal to the library.

>
> Thanks!
> Yordan
>
[...]



-- 
Tzvetomir (Ceco) Stoyanov
VMware Open Source Technology Center

Re: [PATCH v2 01/12] libtracefs: Add new internal APIs for dynamic events

[Steven Rostedt]

On Tue, 2 Nov 2021 06:33:36 +0200
Tzvetomir Stoyanov <tz.stoyanov@gmail.com> wrote:

> > > +
> > > +#define DYNEVENTS_EVENTS "dynamic_events"
> > > +#define KPROBE_EVENTS "kprobe_events"  
> >
> > A definition of KPROBE_EVENTS already exists in /utest/tracefs-utest.c and src/tracefs-kprobes.c
> >
> > Isn't better to move the whole group of definitions of filenames to include/tracefs-local.h?  
> 
> The unit test should use only the official library API, defined in
> tracefs.h. We could move these defines in the official API header, but
> I think these should be internal to the library.

Agreed. In fact, if one day the name changes (which is highly unlikely) we
want the unit tests to fail on that ;-)

-- Steve

[PATCH v2 02/12] libtracefs: Rename tracefs_get_kprobes API

[Tzvetomir Stoyanov (VMware)]

The names of tracefs API should follow the same pattern:
  tracefs_XXX_<action>
Rename tracefs_get_kprobes() to tracefs_kprobes_get() to be
consistent with that pattern.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 Documentation/libtracefs-kprobes.txt |  8 ++++----
 include/tracefs.h                    |  2 +-
 src/tracefs-kprobes.c                |  6 +++---
 utest/tracefs-utest.c                | 10 +++++-----
 4 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/Documentation/libtracefs-kprobes.txt b/Documentation/libtracefs-kprobes.txt
index c10576e..ca48fa9 100644
--- a/Documentation/libtracefs-kprobes.txt
+++ b/Documentation/libtracefs-kprobes.txt
@@ -3,7 +3,7 @@ libtracefs(3)
 
 NAME
 ----
-tracefs_kprobe_raw, tracefs_kretprobe_raw, tracefs_get_kprobes, tracefs_kprobe_info, tracefs_kprobe_clear_all, tracefs_kprobe_clear_probe - Create, list, and destroy kprobes
+tracefs_kprobe_raw, tracefs_kretprobe_raw, tracefs_kprobes_get, tracefs_kprobe_info, tracefs_kprobe_clear_all, tracefs_kprobe_clear_probe - Create, list, and destroy kprobes
 
 SYNOPSIS
 --------
@@ -13,7 +13,7 @@ SYNOPSIS
 
 int tracefs_kprobe_raw(const char pass:[*]system, const char pass:[*]event, const char pass:[*]addr, const char pass:[*]format);
 int tracefs_kretprobe_raw(const char pass:[*]system, const char pass:[*]event, const char pass:[*]addr, const char pass:[*]format);
-char pass:[*]pass:[*]tracefs_get_kprobes(enum tracefs_kprobe_type type);
+char pass:[*]pass:[*]tracefs_kprobes_get(enum tracefs_kprobe_type type);
 enum tracefs_kprobe_type tracefs_kprobe_info(const char pass:[*]group, const char pass:[*]event,
 					     char pass:[*]pass:[*]type, char pass:[*]pass:[*]addr, char pass:[*]pass:[*]format);
 enum tracefs_kprobe_type tracefs_kprobe_type(const char pass:[*]group, const char pass:[*]event)
@@ -36,7 +36,7 @@ document.
 creates a kretprobe instead of a kprobe. The difference is also described
 in the Linux kernel source in the Documentation/trace/kprobetrace.rst file.
 
-*tracefs_get_kprobes*() returns an array of strings (char pass:[*]) that contain
+*tracefs_kprobes_get*() returns an array of strings (char pass:[*]) that contain
 the registered kprobes and kretprobes depending on the given _type_. If _type_ is
 TRACEFS_ALL_KPROBES, then all kprobes found are returned. If _type_ is
 TRACEFS_KPROBE, then only normal kprobes are returned. If _type_ is
@@ -76,7 +76,7 @@ If a parsing error occurs on *tracefs_kprobe_raw*() or *tracefs_kretprobe_raw*()
 then *tracefs_error_last*(3) may be used to retrieve the error message explaining
 the parsing issue.
 
-*tracefs_get_kprobes*() returns an allocate string list of allocated strings
+*tracefs_kprobes_get*() returns an allocate string list of allocated strings
 on success that must be freed with *tracefs_list_free*(3) and returns
 NULL on error.
 
diff --git a/include/tracefs.h b/include/tracefs.h
index ee167be..4e721eb 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -251,7 +251,7 @@ int tracefs_kprobe_raw(const char *system, const char *event,
 		       const char *addr, const char *format);
 int tracefs_kretprobe_raw(const char *system, const char *event,
 			  const char *addr, const char *format);
-char **tracefs_get_kprobes(enum tracefs_kprobe_type type);
+char **tracefs_kprobes_get(enum tracefs_kprobe_type type);
 enum tracefs_kprobe_type tracefs_kprobe_info(const char *group, const char *event,
 					     char **type, char **addr, char **format);
 int tracefs_kprobe_clear_all(bool force);
diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c
index 6fdd8f9..d4c5f9e 100644
--- a/src/tracefs-kprobes.c
+++ b/src/tracefs-kprobes.c
@@ -158,7 +158,7 @@ static int parse_kprobe(char *content, char **saveptr,
 }
 
 /**
- * tracefs_get_kprobes - return a list kprobes (by group/event name)
+ * tracefs_kprobes_get - return a list kprobes (by group/event name)
  * @type: The type of kprobes to return.
  *
  * If @type is TRACEFS_ALL_KPROBES all kprobes in the kprobe_events
@@ -174,7 +174,7 @@ static int parse_kprobe(char *content, char **saveptr,
  * only a NULL pointer.
  * On error, NULL is returned.
  */
-char **tracefs_get_kprobes(enum tracefs_kprobe_type type)
+char **tracefs_kprobes_get(enum tracefs_kprobe_type type)
 {
 	char **list = NULL;
 	char *content;
@@ -357,7 +357,7 @@ static int kprobe_clear_probes(const char *group, bool force)
 	int ret;
 	int i;
 
-	kprobe_list = tracefs_get_kprobes(TRACEFS_ALL_KPROBES);
+	kprobe_list = tracefs_kprobes_get(TRACEFS_ALL_KPROBES);
 	if (!kprobe_list)
 		return -1;
 
diff --git a/utest/tracefs-utest.c b/utest/tracefs-utest.c
index 09bb8f2..7c1a84e 100644
--- a/utest/tracefs-utest.c
+++ b/utest/tracefs-utest.c
@@ -583,7 +583,7 @@ static void test_instance_file(void)
 	free(kaddr);
 	free(kformat);
 
-	kprobes = tracefs_get_kprobes(TRACEFS_ALL_KPROBES);
+	kprobes = tracefs_kprobes_get(TRACEFS_ALL_KPROBES);
 	CU_TEST(kprobes != NULL);
 
 	for (i = 0; kprobes[i]; i++) {
@@ -612,7 +612,7 @@ static void test_instance_file(void)
 	tracefs_list_free(kprobes);
 	CU_TEST(i == 3);
 
-	kprobes = tracefs_get_kprobes(TRACEFS_KPROBE);
+	kprobes = tracefs_kprobes_get(TRACEFS_KPROBE);
 	CU_TEST(kprobes != NULL);
 
 	for (i = 0; kprobes[i]; i++) {
@@ -631,7 +631,7 @@ static void test_instance_file(void)
 	tracefs_list_free(kprobes);
 	CU_TEST(i == 2);
 
-	kprobes = tracefs_get_kprobes(TRACEFS_KRETPROBE);
+	kprobes = tracefs_kprobes_get(TRACEFS_KRETPROBE);
 	CU_TEST(kprobes != NULL);
 
 	for (i = 0; kprobes[i]; i++) {
@@ -663,7 +663,7 @@ static void test_instance_file(void)
 	ret = tracefs_kprobe_clear_probe(KPROBE_2_GROUP, NULL, true);
 	CU_TEST(ret == 0);
 
-	kprobes = tracefs_get_kprobes(TRACEFS_ALL_KPROBES);
+	kprobes = tracefs_kprobes_get(TRACEFS_ALL_KPROBES);
 	CU_TEST(kprobes != NULL);
 
 	for (i = 0; kprobes[i]; i++) {
@@ -682,7 +682,7 @@ static void test_instance_file(void)
 	ret = tracefs_kprobe_clear_all(true);
 	CU_TEST(ret == 0);
 
-	kprobes = tracefs_get_kprobes(TRACEFS_ALL_KPROBES);
+	kprobes = tracefs_kprobes_get(TRACEFS_ALL_KPROBES);
 	CU_TEST(kprobes != NULL);
 
 	CU_TEST(kprobes[0] == NULL);
-- 
2.31.1

[PATCH v2 03/12] libtracefs: New kprobes APIs

[Tzvetomir Stoyanov (VMware)]

In order to be consistent with the other APIs, a new set of kprobe APIs
is introduced:
 tracefs_kprobe_alloc();
 tracefs_kretprobe_alloc();
 tracefs_kprobe_create();
 tracefs_kprobe_destroy();
 tracefs_kprobe_free();
These APIs work with kprobe context, represented by the tracefs_dynevent
structure.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/tracefs.h     |   8 ++
 src/tracefs-kprobes.c | 168 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 176 insertions(+)

diff --git a/include/tracefs.h b/include/tracefs.h
index 4e721eb..85185ce 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -247,6 +247,14 @@ enum tracefs_kprobe_type {
 	TRACEFS_KRETPROBE,
 };
 
+struct tracefs_dynevent *
+tracefs_kprobe_alloc(const char *system, const char *event, const char *addr, const char *format);
+struct tracefs_dynevent *
+tracefs_kretprobe_alloc(const char *system, const char *event,
+			const char *addr, const char *format, int max);
+int tracefs_kprobe_create(struct tracefs_dynevent *kprobe);
+int tracefs_kprobe_destroy(struct tracefs_dynevent *kprobe, bool force);
+void tracefs_kprobe_free(struct tracefs_dynevent *kprobe);
 int tracefs_kprobe_raw(const char *system, const char *event,
 		       const char *addr, const char *format);
 int tracefs_kretprobe_raw(const char *system, const char *event,
diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c
index d4c5f9e..906f914 100644
--- a/src/tracefs-kprobes.c
+++ b/src/tracefs-kprobes.c
@@ -20,6 +20,134 @@
 #define KPROBE_EVENTS "kprobe_events"
 #define KPROBE_DEFAULT_GROUP "kprobes"
 
+static struct tracefs_dynevent *
+kprobe_alloc(enum trace_dynevent_type type, const char *system, const char *event,
+	     const char *addr, const char *format)
+{
+	struct tracefs_dynevent *kp;
+	const char *sys = system;
+	const char *ename = event;
+	char *tmp;
+
+	if (!addr) {
+		errno = EBADMSG;
+		return NULL;
+	}
+	if (!sys)
+		sys = KPROBE_DEFAULT_GROUP;
+
+	if (!event) {
+		ename = strdup(addr);
+		if (!ename)
+			return NULL;
+		tmp = strchr(ename, ':');
+		if (tmp)
+			*tmp = '\0';
+	}
+
+	kp = dynevent_alloc(type, sys, ename, addr, format);
+	if (!event)
+		free((char *)ename);
+
+	return kp;
+}
+
+
+/**
+ * tracefs_kprobe_alloc - Allocate new kprobe context
+ * @system: The system name (NULL for the default kprobes)
+ * @event: The event to create (NULL to use @addr for the event)
+ * @addr: The function and offset (or address) to insert the probe
+ * @format: The format string to define the probe.
+ *
+ * Allocate a kprobe context that will be in the @system group (or kprobes if
+ * @system is NULL). Have the name of @event (or @addr if @event is
+ * NULL). Will be inserted to @addr (function name, with or without
+ * offset, or a address). And the @format will define the format
+ * of the kprobe. See the Linux documentation file under:
+ * Documentation/trace/kprobetrace.rst
+ * The kprobe is not created in the system.
+ *
+ * Return a pointer to a kprobe context on success, or NULL on error.
+ * The returned pointer must be freed with tracefs_kprobe_free()
+ *
+ * errno will be set to EBADMSG if addr is NULL.
+ */
+struct tracefs_dynevent *
+tracefs_kprobe_alloc(const char *system, const char *event, const char *addr, const char *format)
+
+{
+	return kprobe_alloc(TRACE_DYNEVENT_KPROBE, system, event, addr, format);
+}
+
+/**
+ * tracefs_kretprobe_alloc - Allocate new kretprobe context
+ * @system: The system name (NULL for the default kprobes)
+ * @event: The event to create (NULL to use @addr for the event)
+ * @addr: The function and offset (or address) to insert the retprobe
+ * @format: The format string to define the retprobe.
+ *
+ * Allocate a kretprobe that will be in the @system group (or kprobes if
+ * @system is NULL). Have the name of @event (or @addr if @event is
+ * NULL). Will be inserted to @addr (function name, with or without
+ * offset, or a address). And the @format will define the raw format
+ * of the kprobe. See the Linux documentation file under:
+ * Documentation/trace/kprobetrace.rst
+ * The kretprobe is not created in the system.
+ *
+ * Return a pointer to a kprobe context on success, or NULL on error.
+ * The returned pointer must be freed with tracefs_kprobe_free()
+ *
+ * errno will be set to EBADMSG if addr is NULL.
+ */
+struct tracefs_dynevent *
+tracefs_kretprobe_alloc(const char *system, const char *event,
+			const char *addr, const char *format, int max)
+{
+	struct tracefs_dynevent *kp;
+	int ret;
+
+	kp = kprobe_alloc(TRACE_DYNEVENT_KRETPROBE, system, event, addr, format);
+	if (!kp)
+		return NULL;
+	if (max) {
+		free(kp->prefix);
+		kp->prefix = NULL;
+		ret = asprintf(&kp->prefix, "r%d:", max);
+		if (ret < 0)
+			goto error;
+	}
+
+	return kp;
+error:
+	dynevent_free(kp);
+	return NULL;
+}
+
+/**
+ * tracefs_kprobe_create - Create a kprobe or kretprobe in the system
+ * @kprobe: Pointer to a kprobe context, describing the probe
+ *
+ * Return 0 on success, or -1 on error.
+ */
+int tracefs_kprobe_create(struct tracefs_dynevent *kprobe)
+{
+	return dynevent_create(kprobe);
+}
+
+/**
+ * tracefs_kprobe_free - Free a kprobe context
+ * @kprobe: Pointer to a kprobe context
+ *
+ * The kprobe/kretprobe, described by this context, is not
+ * removed from the system by this API. It only frees the memory.
+ */
+void tracefs_kprobe_free(struct tracefs_dynevent *kprobe)
+{
+	dynevent_free(kprobe);
+}
+
+
 static int insert_kprobe(const char *type, const char *system,
 			 const char *event, const char *addr,
 			 const char *format)
@@ -474,3 +602,43 @@ int tracefs_kprobe_clear_probe(const char *system, const char *event, bool force
 
 	return ret < 0 ? -1 : 0;
 }
+
+/**
+ * tracefs_kprobe_destroy - Remove a kprobe or kretprobe from the system
+ * @kprobe: A kprobe context, describing the kprobe that will be deleted.
+ *	    If NULL, all kprobes and kretprobes in the system will be deleted
+ * @force: Will attempt to disable all kprobe events and clear them
+ *
+ * The kprobe/kretprobe context is not freed by this API.
+ * It only removes the probe from the system.
+ *
+ * Return 0 on success, or -1 on error.
+ */
+int tracefs_kprobe_destroy(struct tracefs_dynevent *kprobe, bool force)
+{
+	char **instance_list;
+	int ret;
+
+	if (!kprobe) {
+		if (tracefs_instance_file_clear(NULL, KPROBE_EVENTS) == 0)
+			return 0;
+		if (!force)
+			return -1;
+		/* Attempt to disable all kprobe events */
+		return kprobe_clear_probes(NULL, force);
+	}
+
+	/*
+	 * Since we know we are disabling a specific event, try
+	 * to disable it first before clearing it.
+	 */
+	if (force) {
+		instance_list = tracefs_instances(NULL);
+		disable_events(kprobe->system, kprobe->event, instance_list);
+		tracefs_list_free(instance_list);
+	}
+
+	ret = dynevent_destroy(kprobe);
+
+	return ret < 0 ? -1 : 0;
+}
-- 
2.31.1

Re: [PATCH v2 03/12] libtracefs: New kprobes APIs

[Yordan Karadzhov]

On 1.11.21 г. 11:08, Tzvetomir Stoyanov (VMware) wrote:
> In order to be consistent with the other APIs, a new set of kprobe APIs
> is introduced:
>   tracefs_kprobe_alloc();
>   tracefs_kretprobe_alloc();
>   tracefs_kprobe_create();
>   tracefs_kprobe_destroy();
>   tracefs_kprobe_free();
> These APIs work with kprobe context, represented by the tracefs_dynevent
> structure.
> 
> Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
> ---
>   include/tracefs.h     |   8 ++
>   src/tracefs-kprobes.c | 168 ++++++++++++++++++++++++++++++++++++++++++
>   2 files changed, 176 insertions(+)
> 
> diff --git a/include/tracefs.h b/include/tracefs.h
> index 4e721eb..85185ce 100644
> --- a/include/tracefs.h
> +++ b/include/tracefs.h
> @@ -247,6 +247,14 @@ enum tracefs_kprobe_type {
>   	TRACEFS_KRETPROBE,
>   };
>   
> +struct tracefs_dynevent *
> +tracefs_kprobe_alloc(const char *system, const char *event, const char *addr, const char *format);
> +struct tracefs_dynevent *
> +tracefs_kretprobe_alloc(const char *system, const char *event,
> +			const char *addr, const char *format, int max);
> +int tracefs_kprobe_create(struct tracefs_dynevent *kprobe);
> +int tracefs_kprobe_destroy(struct tracefs_dynevent *kprobe, bool force);
> +void tracefs_kprobe_free(struct tracefs_dynevent *kprobe);
>   int tracefs_kprobe_raw(const char *system, const char *event,
>   		       const char *addr, const char *format);
>   int tracefs_kretprobe_raw(const char *system, const char *event,
> diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c
> index d4c5f9e..906f914 100644
> --- a/src/tracefs-kprobes.c
> +++ b/src/tracefs-kprobes.c
> @@ -20,6 +20,134 @@
>   #define KPROBE_EVENTS "kprobe_events"
>   #define KPROBE_DEFAULT_GROUP "kprobes"
>   
> +static struct tracefs_dynevent *
> +kprobe_alloc(enum trace_dynevent_type type, const char *system, const char *event,
> +	     const char *addr, const char *format)
> +{
> +	struct tracefs_dynevent *kp;
> +	const char *sys = system;
> +	const char *ename = event;
> +	char *tmp;
> +
> +	if (!addr) {
> +		errno = EBADMSG;
> +		return NULL;
> +	}
> +	if (!sys)
> +		sys = KPROBE_DEFAULT_GROUP;
> +
> +	if (!event) {
> +		ename = strdup(addr);
> +		if (!ename)
> +			return NULL;
> +		tmp = strchr(ename, ':');
> +		if (tmp)
> +			*tmp = '\0';
> +	}
> +
> +	kp = dynevent_alloc(type, sys, ename, addr, format);
> +	if (!event)
> +		free((char *)ename);
> +
> +	return kp;
> +}
> +
> +
> +/**
> + * tracefs_kprobe_alloc - Allocate new kprobe context
> + * @system: The system name (NULL for the default kprobes)
> + * @event: The event to create (NULL to use @addr for the event)
> + * @addr: The function and offset (or address) to insert the probe
> + * @format: The format string to define the probe.
> + *
> + * Allocate a kprobe context that will be in the @system group (or kprobes if
> + * @system is NULL). Have the name of @event (or @addr if @event is
> + * NULL). Will be inserted to @addr (function name, with or without
> + * offset, or a address). And the @format will define the format
> + * of the kprobe. See the Linux documentation file under:
> + * Documentation/trace/kprobetrace.rst
> + * The kprobe is not created in the system.
> + *
> + * Return a pointer to a kprobe context on success, or NULL on error.
> + * The returned pointer must be freed with tracefs_kprobe_free()
> + *
> + * errno will be set to EBADMSG if addr is NULL.
> + */
> +struct tracefs_dynevent *
> +tracefs_kprobe_alloc(const char *system, const char *event, const char *addr, const char *format)
> +
> +{
> +	return kprobe_alloc(TRACE_DYNEVENT_KPROBE, system, event, addr, format);
> +}
> +
> +/**
> + * tracefs_kretprobe_alloc - Allocate new kretprobe context
> + * @system: The system name (NULL for the default kprobes)
> + * @event: The event to create (NULL to use @addr for the event)
> + * @addr: The function and offset (or address) to insert the retprobe
> + * @format: The format string to define the retprobe.
> + *

@max is not documented.

> + * Allocate a kretprobe that will be in the @system group (or kprobes if
> + * @system is NULL). Have the name of @event (or @addr if @event is
> + * NULL). Will be inserted to @addr (function name, with or without
> + * offset, or a address). And the @format will define the raw format
> + * of the kprobe. See the Linux documentation file under:
> + * Documentation/trace/kprobetrace.rst
> + * The kretprobe is not created in the system.
> + *
> + * Return a pointer to a kprobe context on success, or NULL on error.
> + * The returned pointer must be freed with tracefs_kprobe_free()
> + *
> + * errno will be set to EBADMSG if addr is NULL.
> + */
> +struct tracefs_dynevent *
> +tracefs_kretprobe_alloc(const char *system, const char *event,
> +			const char *addr, const char *format, int max)
> +{
> +	struct tracefs_dynevent *kp;
> +	int ret;
> +
> +	kp = kprobe_alloc(TRACE_DYNEVENT_KRETPROBE, system, event, addr, format);
> +	if (!kp)
> +		return NULL;
> +	if (max) {
> +		free(kp->prefix);
> +		kp->prefix = NULL;
> +		ret = asprintf(&kp->prefix, "r%d:", max);
> +		if (ret < 0)
> +			goto error;
> +	}
> +
> +	return kp;
> +error:
> +	dynevent_free(kp);
> +	return NULL;
> +}
> +
> +/**
> + * tracefs_kprobe_create - Create a kprobe or kretprobe in the system
> + * @kprobe: Pointer to a kprobe context, describing the probe
> + *
> + * Return 0 on success, or -1 on error.
> + */
> +int tracefs_kprobe_create(struct tracefs_dynevent *kprobe)
> +{
> +	return dynevent_create(kprobe);
> +}
> +

hmm, what will happen if if you have a code like this:


struct tracefs_dynevent *synth = tracefs_synth_alloc(...)

int ret = tracefs_kprobe_create(synth);


Are you just giving several additional fake names to the same function ('dynevent_create()')?


> +/**
> + * tracefs_kprobe_free - Free a kprobe context
> + * @kprobe: Pointer to a kprobe context
> + *
> + * The kprobe/kretprobe, described by this context, is not
> + * removed from the system by this API. It only frees the memory.
> + */
> +void tracefs_kprobe_free(struct tracefs_dynevent *kprobe)
> +{
> +	dynevent_free(kprobe);
> +}
> +

The same argument applys here.

Thanks!
Yordan

> +
>   static int insert_kprobe(const char *type, const char *system,
>   			 const char *event, const char *addr,
>   			 const char *format)
> @@ -474,3 +602,43 @@ int tracefs_kprobe_clear_probe(const char *system, const char *event, bool force
>   
>   	return ret < 0 ? -1 : 0;
>   }
> +
> +/**
> + * tracefs_kprobe_destroy - Remove a kprobe or kretprobe from the system
> + * @kprobe: A kprobe context, describing the kprobe that will be deleted.
> + *	    If NULL, all kprobes and kretprobes in the system will be deleted
> + * @force: Will attempt to disable all kprobe events and clear them
> + *
> + * The kprobe/kretprobe context is not freed by this API.
> + * It only removes the probe from the system.
> + *
> + * Return 0 on success, or -1 on error.
> + */
> +int tracefs_kprobe_destroy(struct tracefs_dynevent *kprobe, bool force)
> +{
> +	char **instance_list;
> +	int ret;
> +
> +	if (!kprobe) {
> +		if (tracefs_instance_file_clear(NULL, KPROBE_EVENTS) == 0)
> +			return 0;
> +		if (!force)
> +			return -1;
> +		/* Attempt to disable all kprobe events */
> +		return kprobe_clear_probes(NULL, force);
> +	}
> +
> +	/*
> +	 * Since we know we are disabling a specific event, try
> +	 * to disable it first before clearing it.
> +	 */
> +	if (force) {
> +		instance_list = tracefs_instances(NULL);
> +		disable_events(kprobe->system, kprobe->event, instance_list);
> +		tracefs_list_free(instance_list);
> +	}
> +
> +	ret = dynevent_destroy(kprobe);
> +
> +	return ret < 0 ? -1 : 0;
> +}
> 

Re: [PATCH v2 03/12] libtracefs: New kprobes APIs

[Tzvetomir Stoyanov]

On Mon, Nov 1, 2021 at 7:22 PM Yordan Karadzhov <y.karadz@gmail.com> wrote:
>
>
[ ... ]
> > +/**
> > + * tracefs_kprobe_create - Create a kprobe or kretprobe in the system
> > + * @kprobe: Pointer to a kprobe context, describing the probe
> > + *
> > + * Return 0 on success, or -1 on error.
> > + */
> > +int tracefs_kprobe_create(struct tracefs_dynevent *kprobe)
> > +{
> > +     return dynevent_create(kprobe);
> > +}
> > +
>
> hmm, what will happen if if you have a code like this:
>
>
> struct tracefs_dynevent *synth = tracefs_synth_alloc(...)
>
> int ret = tracefs_kprobe_create(synth);
>
>
> Are you just giving several additional fake names to the same function ('dynevent_create()')?
>
>

Yes, that will work. All dynamic events - kprobes, uprobes, eprobes
and synthetic events have almost the same configuration logic, which
is handled by these dynevent_... internal APIs. That makes the code
more consistent and reusable.
I see three possible approaches to handle that:
 1. Create structures like that:
      struct tracefs_kprobe {
         struct tracefs_dynevent dynevent;
      };
   and use only that type in krpobe specific APIs:
     int tracefs_kprobe_create(struct tracefs_kprobe *kprobe)
     {
         return dynevent_create(&kprobe->dynevent);
     }

2. Expose the dynevent_... APIs directly:
    struct tracefs_dynevent *synth =
tracefs_dynevent_alloc(TRACE_DYNEVENT_SYNTH, ...);
    struct tracefs_dynevent *kprobe =
tracefs_dynevent_alloc(TRACE_DYNEVENT_KPROBE, ...);

    ret = tracefs_dynevent_create(synth);
    ret = tracefs_dynevent_create(kprobe);

 The problem here is that there are some small differences between
dynamic events - some parameters are mandatory for one event and
optional for another. That can be handled in the
tracefs_dynevent_alloc() API, but could be confusing for the library
users.

3. Mixed between 1) and 2), the current approach.

The first one adds a lot of overhead, a different set of APIs for each
type of dynamic event - but maybe it is more clear for the library
users. The second is straightforward for implementation, less APIs -
but that could be confusing for the users.

> > +/**
> > + * tracefs_kprobe_free - Free a kprobe context
> > + * @kprobe: Pointer to a kprobe context
> > + *
> > + * The kprobe/kretprobe, described by this context, is not
> > + * removed from the system by this API. It only frees the memory.
> > + */
> > +void tracefs_kprobe_free(struct tracefs_dynevent *kprobe)
> > +{
> > +     dynevent_free(kprobe);
> > +}
> > +
>
> The same argument applys here.
>
> Thanks!
> Yordan
>

Thanks for the review!

-- 
Tzvetomir (Ceco) Stoyanov
VMware Open Source Technology Center

Re: [PATCH v2 03/12] libtracefs: New kprobes APIs

[Yordan Karadzhov]

On 2.11.21 г. 6:58, Tzvetomir Stoyanov wrote:
> On Mon, Nov 1, 2021 at 7:22 PM Yordan Karadzhov <y.karadz@gmail.com> wrote:
>>
>>
> [ ... ]
>>> +/**
>>> + * tracefs_kprobe_create - Create a kprobe or kretprobe in the system
>>> + * @kprobe: Pointer to a kprobe context, describing the probe
>>> + *
>>> + * Return 0 on success, or -1 on error.
>>> + */
>>> +int tracefs_kprobe_create(struct tracefs_dynevent *kprobe)
>>> +{
>>> +     return dynevent_create(kprobe);
>>> +}
>>> +
>>
>> hmm, what will happen if if you have a code like this:
>>
>>
>> struct tracefs_dynevent *synth = tracefs_synth_alloc(...)
>>
>> int ret = tracefs_kprobe_create(synth);
>>
>>
>> Are you just giving several additional fake names to the same function ('dynevent_create()')?
>>
>>
> 
> Yes, that will work. All dynamic events - kprobes, uprobes, eprobes
> and synthetic events have almost the same configuration logic, which
> is handled by these dynevent_... internal APIs. That makes the code
> more consistent and reusable.
> I see three possible approaches to handle that:
>   1. Create structures like that:
>        struct tracefs_kprobe {
>           struct tracefs_dynevent dynevent;
>        };
>     and use only that type in krpobe specific APIs:
>       int tracefs_kprobe_create(struct tracefs_kprobe *kprobe)
>       {
>           return dynevent_create(&kprobe->dynevent);
>       }
> 
> 2. Expose the dynevent_... APIs directly:
>      struct tracefs_dynevent *synth =
> tracefs_dynevent_alloc(TRACE_DYNEVENT_SYNTH, ...);

I would prefer taking this approach. It is OK to also have several helper constructors like tracefs_kprobe_alloc(), 
tracefs_synth_alloc(), etc. that will call internally dynevent_alloc().

In principle having multiple constructors is OK.


>      struct tracefs_dynevent *kprobe =
> tracefs_dynevent_alloc(TRACE_DYNEVENT_KPROBE, ...);
> 
>      ret = tracefs_dynevent_create(synth);
>      ret = tracefs_dynevent_create(kprobe);
> 

Yes, this is OK as well.

We only have a single type (struct tracefs_dynevent) so there must be a single create. And what is even more important: 
there must be ONLY ONE destructor.

Think about the usecase of the APIs. You create an object using one of the constructors. Later at some point you want to 
use the objects and after this finally you want to destroy it. If we have multiple/specialized "create" and "destroy" 
versions for the same object type, the user must somehow keep its own record of which constructor had been used trough 
the entire live of the object in order to know which is the proper destructor to call at the end.

Thanks!
Yordan


>   The problem here is that there are some small differences between
> dynamic events - some parameters are mandatory for one event and
> optional for another. That can be handled in the
> tracefs_dynevent_alloc() API, but could be confusing for the library
> users.
> 
> 3. Mixed between 1) and 2), the current approach.
> 
> The first one adds a lot of overhead, a different set of APIs for each
> type of dynamic event - but maybe it is more clear for the library
> users. The second is straightforward for implementation, less APIs -
> but that could be confusing for the users.
> 
>>> +/**
>>> + * tracefs_kprobe_free - Free a kprobe context
>>> + * @kprobe: Pointer to a kprobe context
>>> + *
>>> + * The kprobe/kretprobe, described by this context, is not
>>> + * removed from the system by this API. It only frees the memory.
>>> + */
>>> +void tracefs_kprobe_free(struct tracefs_dynevent *kprobe)
>>> +{
>>> +     dynevent_free(kprobe);
>>> +}
>>> +
>>
>> The same argument applys here.
>>
>> Thanks!
>> Yordan
>>
> 
> Thanks for the review!
> 

Re: [PATCH v2 03/12] libtracefs: New kprobes APIs

[Steven Rostedt]

On Tue, 2 Nov 2021 09:43:16 +0200
Yordan Karadzhov <y.karadz@gmail.com> wrote:

> > 2. Expose the dynevent_... APIs directly:
> >      struct tracefs_dynevent *synth =
> > tracefs_dynevent_alloc(TRACE_DYNEVENT_SYNTH, ...);  
> 
> I would prefer taking this approach. It is OK to also have several helper constructors like tracefs_kprobe_alloc(), 
> tracefs_synth_alloc(), etc. that will call internally dynevent_alloc().
> 
> In principle having multiple constructors is OK.

I agree with having multiple constructors, as that makes it easier to think
about what is being created and how to manipulate it. The dynamic event
structure has a type field and it should be used to make sure that
modifications that only should happen to kprobes only happens on dynamic
events created as a kprobe, and errors on everything else.

> 
> 
> >      struct tracefs_dynevent *kprobe =
> > tracefs_dynevent_alloc(TRACE_DYNEVENT_KPROBE, ...);
> > 
> >      ret = tracefs_dynevent_create(synth);
> >      ret = tracefs_dynevent_create(kprobe);
> >   
> 
> Yes, this is OK as well.

Agreed.

> 
> We only have a single type (struct tracefs_dynevent) so there must be a single create. And what is even more important: 
> there must be ONLY ONE destructor.

I wouldn't be so strong as to use "must" but I do agree that it will
simplify the usage of the API. It would be more analogous to free() where
you have several different constructors that state in the man page (must be
freed with free). Same here. Each constructor's man page must state: "must
be freed with tracefs_dynevent_free()"

Removing from the system any dynamic event should also just use
tracefs_dynevent_destroy(). Having the type of event in the structure means
that knowing how to destroy it can be multiplexed inside the library, and
not burden the user in such cases. This way, the user could create a bunch
of dynamic event types in an array or linked list, and destroy them at the
end without having to keep track of which one is which.

-- Steve

> 
> Think about the usecase of the APIs. You create an object using one of the constructors. Later at some point you want to 
> use the objects and after this finally you want to destroy it. If we have multiple/specialized "create" and "destroy" 
> versions for the same object type, the user must somehow keep its own record of which constructor had been used trough 
> the entire live of the object in order to know which is the proper destructor to call at the end.

[PATCH v2 04/12] libtracefs: Remove redundant kprobes APIs

[Tzvetomir Stoyanov (VMware)]

The newly introduced API tracefs_kprobe_destroy() can be used to clear a
specific kprobe or all kprobes from the system. These legacy APIs are
removed as redundant:
 tracefs_kprobe_clear_all();
 tracefs_kprobe_clear_probe();

There is one functionality, missing in the new API - clearing all
kprobes from specific system only. If this is needed,
tracefs_kprobe_destroy() can be extended with that use case.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/tracefs.h     |  2 --
 src/tracefs-kprobes.c | 62 -------------------------------------------
 2 files changed, 64 deletions(-)

diff --git a/include/tracefs.h b/include/tracefs.h
index 85185ce..d72582b 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -262,8 +262,6 @@ int tracefs_kretprobe_raw(const char *system, const char *event,
 char **tracefs_kprobes_get(enum tracefs_kprobe_type type);
 enum tracefs_kprobe_type tracefs_kprobe_info(const char *group, const char *event,
 					     char **type, char **addr, char **format);
-int tracefs_kprobe_clear_all(bool force);
-int tracefs_kprobe_clear_probe(const char *system, const char *event, bool force);
 
 enum tracefs_hist_key_type {
 	TRACEFS_HIST_KEY_NORMAL = 0,
diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c
index 906f914..0596f34 100644
--- a/src/tracefs-kprobes.c
+++ b/src/tracefs-kprobes.c
@@ -541,68 +541,6 @@ static int kprobe_clear_probes(const char *group, bool force)
 	return ret;
 }
 
-/**
- * tracefs_kprobe_clear_all - clear kprobe events
- * @force: Will attempt to disable all kprobe events and clear them
- *
- * Will remove all defined kprobe events. If any of them are enabled,
- * and @force is not set, then it will error with -1 and errno to be
- * EBUSY. If @force is set, then it will attempt to disable all the kprobe
- * events in all instances, and try again.
- *
- * Returns zero on success, -1 otherwise.
- */
-int tracefs_kprobe_clear_all(bool force)
-{
-	if (tracefs_instance_file_clear(NULL, KPROBE_EVENTS) == 0)
-		return 0;
-
-	if (!force)
-		return -1;
-
-	/* Attempt to disable all kprobe events */
-	return kprobe_clear_probes(NULL, force);
-}
-
-/**
- * tracefs_kprobe_clear_all - clear kprobe events
- * @system: System to clear (NULL means default)
- * @event: Name of probe to clear in system (NULL for all probes in system)
- * @force: Will attempt to disable all kprobe events and clear them
- *
- * Will remove the kprobes that match the @system and @event. If @system
- * is NULL, then "kprobes" is used and will ignore all other system
- * groups of kprobes. The @event is NULL then all events under the given
- * @system are removed, otherwise only the event that matches.
- *
- * Returns zero on success, -1 otherwise.
- */
-int tracefs_kprobe_clear_probe(const char *system, const char *event, bool force)
-{
-	char **instance_list;
-	int ret;
-
-	if (!system)
-		system = "kprobes";
-
-	if (!event)
-		return kprobe_clear_probes(system, force);
-
-	/*
-	 * Since we know we are disabling a specific event, try
-	 * to disable it first before clearing it.
-	 */
-	if (force) {
-		instance_list = tracefs_instances(NULL);
-		disable_events(system, event, instance_list);
-		tracefs_list_free(instance_list);
-	}
-
-	ret = clear_kprobe(system, event);
-
-	return ret < 0 ? -1 : 0;
-}
-
 /**
  * tracefs_kprobe_destroy - Remove a kprobe or kretprobe from the system
  * @kprobe: A kprobe context, describing the kprobe that will be deleted.
-- 
2.31.1

[PATCH v2 05/12] libtracefs: Reimplement tracefs_kprobes_get API

[Tzvetomir Stoyanov (VMware)]

In order to unify the code and reuse the internal helpers for dynamic
events helpers, the tracefs_kprobes_get() API is reimplemented using
the new dynamic events APIs.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/tracefs.h     |   2 +-
 src/tracefs-kprobes.c | 121 ++++++++++--------------------------------
 2 files changed, 28 insertions(+), 95 deletions(-)

diff --git a/include/tracefs.h b/include/tracefs.h
index d72582b..27da808 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -259,7 +259,7 @@ int tracefs_kprobe_raw(const char *system, const char *event,
 		       const char *addr, const char *format);
 int tracefs_kretprobe_raw(const char *system, const char *event,
 			  const char *addr, const char *format);
-char **tracefs_kprobes_get(enum tracefs_kprobe_type type);
+struct tracefs_dynevent **tracefs_kprobes_get(enum tracefs_kprobe_type type);
 enum tracefs_kprobe_type tracefs_kprobe_info(const char *group, const char *event,
 					     char **type, char **addr, char **format);
 
diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c
index 0596f34..be49e7d 100644
--- a/src/tracefs-kprobes.c
+++ b/src/tracefs-kprobes.c
@@ -286,77 +286,28 @@ static int parse_kprobe(char *content, char **saveptr,
 }
 
 /**
- * tracefs_kprobes_get - return a list kprobes (by group/event name)
+ * tracefs_kprobes_get - return an array of pointers to kprobes
  * @type: The type of kprobes to return.
  *
- * If @type is TRACEFS_ALL_KPROBES all kprobes in the kprobe_events
- * are returned. Otherwise if it is TRACEFS_KPROBE, then only
+ * If @type is TRACEFS_ALL_KPROBES all kprobes in the system are returned.
+ * Otherwise if it is TRACEFS_KPROBE, then only
  * normal kprobes (p:) are returned, or if type is TRACEFS_KRETPROBE
  * then only kretprobes (r:) are returned.
  *
- * Returns a list of strings that contain the kprobes that exist
- * in the kprobe_events files. The strings returned are in the
- * "group/event" format.
- * The list must be freed with tracefs_list_free().
- * If there are no kprobes, a list is still returned, but it contains
- * only a NULL pointer.
- * On error, NULL is returned.
+ * In case of an error, NULL is returned.
+ * In case of success, an array of pointers to kprobes is allocated and returned.
+ * The last element is a NULL pointer. The array must be freed with tracefs_dynevent_list_free().
  */
-char **tracefs_kprobes_get(enum tracefs_kprobe_type type)
+struct tracefs_dynevent **tracefs_kprobes_get(enum tracefs_kprobe_type type)
 {
-	char **list = NULL;
-	char *content;
-	char *saveptr;
-	char *event;
-	char *ktype;
-	int ret;
-
-	errno = 0;
-	content = tracefs_instance_file_read(NULL, KPROBE_EVENTS, NULL);
-	if (!content) {
-		if (errno)
-			return NULL;
-		/* content is NULL on empty file, return an empty list */
-		return trace_list_create_empty();
-	}
-
-	ret = parse_kprobe(content, &saveptr, &ktype, NULL, &event, NULL, NULL);
-
-	while (!ret) {
-		char **tmp;
-
-		if (type != TRACEFS_ALL_KPROBES) {
-			switch (*ktype) {
-			case 'p':
-				if (type != TRACEFS_KPROBE)
-					goto next;
-				break;
-			case 'r':
-				if (type != TRACEFS_KRETPROBE)
-					goto next;
-				break;
-			default:
-				goto next;
-			}
-		}
+	unsigned long mask = 0;
 
-		tmp = tracefs_list_add(list, event);
-		if (!tmp)
-			goto fail;
-		list = tmp;
- next:
-		ret = parse_kprobe(NULL, &saveptr, &ktype, NULL, &event, NULL, NULL);
-	}
+	if (type == TRACEFS_KPROBE || type == TRACEFS_ALL_KPROBES)
+		SET_BIT(mask, TRACE_DYNEVENT_KPROBE);
+	if (type == TRACEFS_KRETPROBE || type == TRACEFS_ALL_KPROBES)
+		SET_BIT(mask, TRACE_DYNEVENT_KRETPROBE);
 
-	if (!list)
-		list = trace_list_create_empty();
- out:
-	free(content);
-	return list;
- fail:
-	tracefs_list_free(list);
-	list = NULL;
-	goto out;
+	return dynevent_get_all(mask, NULL);
 }
 
 /**
@@ -464,29 +415,16 @@ static void disable_events(const char *system, const char *event,
 	return;
 }
 
-static int clear_kprobe(const char *system, const char *event)
-{
-	/* '-' + ':' + '/' + '\n' + '\0' = 5 bytes */
-	int len = strlen(system) + strlen(event) + 5;
-	char content[len];
-
-	sprintf(content, "-:%s/%s", system, event);
-	return tracefs_instance_file_append(NULL, KPROBE_EVENTS, content);
-}
-
 static int kprobe_clear_probes(const char *group, bool force)
 {
+	struct tracefs_dynevent **kprobes;
 	char **instance_list;
-	char **kprobe_list;
-	char *saveptr;
-	char *system;
-	char *kprobe;
-	char *event;
 	int ret;
 	int i;
 
-	kprobe_list = tracefs_kprobes_get(TRACEFS_ALL_KPROBES);
-	if (!kprobe_list)
+	kprobes = tracefs_kprobes_get(TRACEFS_ALL_KPROBES);
+	/* No krpobes or error getting them */
+	if (!kprobes)
 		return -1;
 
 	instance_list = tracefs_instances(NULL);
@@ -503,26 +441,21 @@ static int kprobe_clear_probes(const char *group, bool force)
 	 */
 	ret = group ? 0 : -1;
 
-	for (i = 0; kprobe_list[i]; i++) {
-		kprobe = kprobe_list[i];
-
-		system = strtok_r(kprobe, "/", &saveptr);
-		if (!system)
-			goto out;
-
-		event = strtok_r(NULL," ", &saveptr);
-		if (!event)
-			goto out;
+	for (i = 0; kprobes[i]; i++) {
 
 		/* Skip if this does not match a given system */
-		if (group && strcmp(system, group) != 0)
-			continue;
+		if (group) {
+			if (!kprobes[i]->system)
+				continue;
+			if (strcmp(kprobes[i]->system, group) != 0)
+				continue;
+		}
 
 		if (force)
-			disable_events(system, event, instance_list);
+			disable_events(kprobes[i]->system, kprobes[i]->event, instance_list);
 
 		if (group) {
-			ret = clear_kprobe(system, event);
+			ret = dynevent_destroy(kprobes[i]);
 			if (ret < 0)
 				goto out;
 		} else {
@@ -537,7 +470,7 @@ static int kprobe_clear_probes(const char *group, bool force)
 	}
  out:
 	tracefs_list_free(instance_list);
-	tracefs_list_free(kprobe_list);
+	tracefs_dynevent_list_free(kprobes);
 	return ret;
 }
 
-- 
2.31.1

[PATCH v2 06/12] libtracefs: Change tracefs_kprobe_info API

[Tzvetomir Stoyanov (VMware)]

In order to make kprobe APIs consistent with the other libtracefs APIs,
the tracefs_kprobe_info() API is reimplemented and changed to work with
the library kprobe context structure.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/tracefs.h     |   5 +-
 src/tracefs-kprobes.c | 175 ++++++++++++++++--------------------------
 2 files changed, 69 insertions(+), 111 deletions(-)

diff --git a/include/tracefs.h b/include/tracefs.h
index 27da808..f75fd92 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -260,8 +260,9 @@ int tracefs_kprobe_raw(const char *system, const char *event,
 int tracefs_kretprobe_raw(const char *system, const char *event,
 			  const char *addr, const char *format);
 struct tracefs_dynevent **tracefs_kprobes_get(enum tracefs_kprobe_type type);
-enum tracefs_kprobe_type tracefs_kprobe_info(const char *group, const char *event,
-					     char **type, char **addr, char **format);
+enum tracefs_kprobe_type tracefs_kprobe_info(struct tracefs_dynevent *kprobe,
+					     char **system, char **event,
+					     char **prefix, char **addr, char **format);
 
 enum tracefs_hist_key_type {
 	TRACEFS_HIST_KEY_NORMAL = 0,
diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c
index be49e7d..390e211 100644
--- a/src/tracefs-kprobes.c
+++ b/src/tracefs-kprobes.c
@@ -233,58 +233,6 @@ int tracefs_kretprobe_raw(const char *system, const char *event,
 	return insert_kprobe("r", system, event, addr, format);
 }
 
-/*
- * Helper function to parse kprobes.
- * @content: The content of kprobe_events on the first iteration.
- *           NULL on next iterations.
- * @saveptr: Same as saveptr for strtok_r
- * @type: Where to store the type (before ':')
- * @system: Store the system of the kprobe (NULL to have event contain
- *          both system and event, as in "kprobes/myprobe").
- * @event: Where to store the event.
- * @addr: Where to store the addr (may be NULL to ignore)
- * @format: Where to store the format (may be NULL to ignore)
- */
-static int parse_kprobe(char *content, char **saveptr,
-			char **type, char **system, char **event,
-			char **addr, char **format)
-{
-	char *p;
-
-	p = strtok_r(content, ":", saveptr);
-	if (!p)
-		return 1; /* eof */
-	*type = p;
-
-	if (system) {
-		p = strtok_r(NULL, "/", saveptr);
-		if (!p)
-			return -1;
-		*system = p;
-	}
-
-	p = strtok_r(NULL, " ", saveptr);
-	if (!p)
-		return -1;
-	*event = p;
-
-	if (addr || format) {
-		p = strtok_r(NULL, " ", saveptr);
-		if (!p)
-			return -1;
-		if (addr)
-			*addr = p;
-	}
-
-	p = strtok_r(NULL, "\n", saveptr);
-	if (!p)
-		return -1;
-	if (format)
-		*format = p;
-
-	return 0;
-}
-
 /**
  * tracefs_kprobes_get - return an array of pointers to kprobes
  * @type: The type of kprobes to return.
@@ -311,74 +259,83 @@ struct tracefs_dynevent **tracefs_kprobes_get(enum tracefs_kprobe_type type)
 }
 
 /**
- * tracefs_kprobe_info - return the type of kprobe specified.
- * @group: The group the kprobe is in (NULL for the default "kprobes")
- * @event: The name of the kprobe to find.
- * @type: String to return kprobe type (before ':') NULL to ignore.
- * @addr: String to return address kprobe is attached to. NULL to ignore.
- * @format: String to return kprobe format. NULL to ignore.
+ * tracefs_kprobe_info - return details of a kprobe
+ * @kprobe: A kprobe context, describing given kprobe.
+ * @group: return, group in which the kprobe is configured
+ * @event: return, name of the kprobe event
+ * @prefix: return, prefix string of the kprobe
+ *	    for kretprobes, the maxactive count is encoded in the prefix
+ * @addr: return, the function and offset (or address) of the kprobe
+ * @format: return, the format string of the kprobe
  *
- * If @type, @addr, or @format is non NULL, then the returned string
- * must be freed with free(). They will also be set to NULL, and
- * even on error, they may contain strings to be freed. If they are
- * not NULL, then they still need to be freed.
- *
- * Returns TRACEFS_ALL_KPROBES if an error occurs or the kprobe is not found,
- *            or the probe is of an unknown type.
- * TRACEFS_KPROBE if the type of kprobe found is a normal kprobe.
- * TRACEFS_KRETPROBE if the type of kprobe found is a kretprobe.
+ * Returns the type of the kprobe, or TRACEFS_ALL_KPROBES in case of an error.
+ * Any of the @group, @event, @prefix, @addr and @format parameters are optional.
+ * If a valid pointer is passed, in case of success - a string is allocated and returned.
+ * These strings must be freed with free().
  */
-enum tracefs_kprobe_type tracefs_kprobe_info(const char *group, const char *event,
-					     char **type, char **addr, char **format)
+enum tracefs_kprobe_type tracefs_kprobe_info(struct tracefs_dynevent *kprobe,
+					     char **system, char **event,
+					     char **prefix, char **addr, char **format)
 {
-	enum tracefs_kprobe_type rtype = TRACEFS_ALL_KPROBES;
-	char *saveptr;
-	char *content;
-	char *system;
-	char *probe;
-	char *ktype;
-	char *kaddr;
-	char *kfmt;
-	int ret;
-
-	if (!group)
-		group = KPROBE_DEFAULT_GROUP;
-
-	if (type)
-		*type = NULL;
+	if (system)
+		*system = NULL;
+	if (event)
+		*event = NULL;
+	if (prefix)
+		*prefix = NULL;
 	if (addr)
 		*addr = NULL;
 	if (format)
 		*format = NULL;
 
-	content = tracefs_instance_file_read(NULL, KPROBE_EVENTS, NULL);
-	if (!content)
-		return rtype;
-
-	ret = parse_kprobe(content, &saveptr, &ktype, &system, &probe,
-			   &kaddr, &kfmt);
-
-	while (!ret) {
-
-		if (!strcmp(system, group) && !strcmp(probe, event)) {
-			if (type)
-				*type = strdup(ktype);
-			if (addr)
-				*addr = strdup(kaddr);
-			if (format)
-				*format = strdup(kfmt);
+	if (!kprobe)
+		return TRACEFS_ALL_KPROBES;
 
-			switch (*ktype) {
-			case 'p': rtype = TRACEFS_KPROBE; break;
-			case 'r': rtype = TRACEFS_KRETPROBE; break;
-			}
-			break;
+	if (system) {
+		if (kprobe->system) {
+			*system = strdup(kprobe->system);
+			if (!(*system))
+				goto error;
 		}
-		ret = parse_kprobe(NULL, &saveptr, &ktype, &system, &probe,
-				   &kaddr, &kfmt);
 	}
-	free(content);
-	return rtype;
+	if (event) {
+		*event = strdup(kprobe->event);
+		if (!(*event))
+			goto error;
+	}
+	if (prefix) {
+		*prefix = strdup(kprobe->prefix);
+		if (!(*prefix))
+			goto error;
+	}
+	if (addr && kprobe->address) {
+		*addr = strdup(kprobe->address);
+		if (!(*addr))
+			goto error;
+	}
+	if (format && kprobe->format) {
+		*format = strdup(kprobe->format);
+		if (!(*format))
+			goto error;
+	}
+
+	if (kprobe->type == TRACE_DYNEVENT_KPROBE)
+		return TRACEFS_KPROBE;
+	if (kprobe->type == TRACE_DYNEVENT_KRETPROBE)
+		return TRACEFS_KRETPROBE;
+
+error:
+	if (system)
+		free(*system);
+	if (event)
+		free(*event);
+	if (prefix)
+		free(*prefix);
+	if (addr)
+		free(*addr);
+	if (format)
+		free(*format);
+	return TRACEFS_ALL_KPROBES;
 }
 
 static void disable_events(const char *system, const char *event,
-- 
2.31.1

[PATCH v2 07/12] libtracefs: Reimplement kprobe raw APIs

[Tzvetomir Stoyanov (VMware)]

In order to unify the code and use the new dynamic event helpers, these
kprobe APIs are rewritten:
 kracefs_kprobe_raw()
 kracefs_kretprobe_raw()
The definition and logic of the APIs remain the same.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 src/tracefs-kprobes.c | 38 ++++++++++----------------------------
 1 file changed, 10 insertions(+), 28 deletions(-)

diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c
index 390e211..672e748 100644
--- a/src/tracefs-kprobes.c
+++ b/src/tracefs-kprobes.c
@@ -147,38 +147,20 @@ void tracefs_kprobe_free(struct tracefs_dynevent *kprobe)
 	dynevent_free(kprobe);
 }
 
-
-static int insert_kprobe(const char *type, const char *system,
-			 const char *event, const char *addr,
-			 const char *format)
+static int kprobe_raw(enum trace_dynevent_type type, const char *system,
+		      const char *event, const char *addr, const char *format)
 {
-	char *str;
+	static struct tracefs_dynevent *kp;
 	int ret;
 
-	if (!tracefs_file_exists(NULL, KPROBE_EVENTS))
-		return -1;
-
-	errno = EBADMSG;
-	if (!addr || !format)
-		return -1;
-
-	if (!event)
-		event = addr;
-
-	if (system)
-		ret = asprintf(&str, "%s:%s/%s %s %s\n",
-			       type, system, event, addr, format);
-	else
-		ret = asprintf(&str, "%s:%s %s %s\n",
-			       type, event, addr, format);
-
-	if (ret < 0)
+	kp = kprobe_alloc(type, system, event, addr, format);
+	if (!kp)
 		return -1;
 
-	ret = tracefs_instance_file_append(NULL, KPROBE_EVENTS, str);
-	free(str);
+	ret = dynevent_create(kp);
+	dynevent_free(kp);
 
-	return ret < 0 ? ret : 0;
+	return ret;
 }
 
 /**
@@ -204,7 +186,7 @@ static int insert_kprobe(const char *type, const char *system,
 int tracefs_kprobe_raw(const char *system, const char *event,
 		       const char *addr, const char *format)
 {
-	return insert_kprobe("p", system, event, addr, format);
+	return kprobe_raw(TRACE_DYNEVENT_KPROBE, system, event, addr, format);
 }
 
 /**
@@ -230,7 +212,7 @@ int tracefs_kprobe_raw(const char *system, const char *event,
 int tracefs_kretprobe_raw(const char *system, const char *event,
 			  const char *addr, const char *format)
 {
-	return insert_kprobe("r", system, event, addr, format);
+	return kprobe_raw(TRACE_DYNEVENT_KRETPROBE, system, event, addr, format);
 }
 
 /**
-- 
2.31.1

[PATCH v2 08/12] libtracefs: Extend kprobes unit test

[Tzvetomir Stoyanov (VMware)]

As there are a lot of changes in the libtracefs kprobes APIs, the unit
test of that functionality should be updated. A new test section is
added, for testing the all kprobes APIs.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 utest/tracefs-utest.c | 408 ++++++++++++++++++++++++------------------
 1 file changed, 238 insertions(+), 170 deletions(-)

diff --git a/utest/tracefs-utest.c b/utest/tracefs-utest.c
index 7c1a84e..f95d4bb 100644
--- a/utest/tracefs-utest.c
+++ b/utest/tracefs-utest.c
@@ -28,22 +28,6 @@
 #define TRACE_ON	"tracing_on"
 #define TRACE_CLOCK	"trace_clock"
 
-#define KPROBE_EVENTS	"kprobe_events"
-
-#define KPROBE_1_NAME	"mkdir"
-#define KPROBE_1_GROUP	"kprobes"
-#define KPROBE_1_ADDR	"do_mkdirat"
-#define KPROBE_1_FMT	"path=+u0($arg2):ustring"
-
-#define KPROBE_2_NAME	"open"
-#define KPROBE_2_GROUP	"myprobe"
-#define KPROBE_2_ADDR	"do_sys_openat2"
-#define KPROBE_2_FMT	"file=+u0($arg2):ustring flags=+0($arg3):x64"
-
-#define KRETPROBE_NAME	"retopen"
-#define KRETPROBE_ADDR	"do_sys_openat2"
-#define KRETPROBE_FMT	"ret=$retval"
-
 #define SQL_1_EVENT	"wakeup_1"
 #define SQL_1_SQL	"select sched_switch.next_pid as woke_pid, sched_waking.common_pid as waking_pid from sched_waking join sched_switch on sched_switch.next_pid = sched_waking.pid"
 
@@ -457,28 +441,258 @@ static void test_instance_file_read(struct tracefs_instance *inst, const char *f
 	free(file);
 }
 
+#define KPROBE_DEFAULT_GROUP "kprobes"
+struct kprobe_test {
+	enum tracefs_kprobe_type type;
+	char *prefix;
+	char *system;
+	char *event;
+	char *address;
+	char *format;
+};
+
+static bool check_kprobes(struct kprobe_test *kprobes, int count,
+			  struct tracefs_dynevent **devents, bool in_system)
+{
+
+	enum tracefs_kprobe_type ktype;
+	char *ename;
+	char *kaddress;
+	char *kevent;
+	char *ksystem;
+	char *kformat;
+	char *kprefix;
+	int found = 0;
+	int ret;
+	int i, j;
+
+	for (i = 0; devents[i]; i++) {
+		ktype = tracefs_kprobe_info(devents[i], &ksystem,
+					   &kevent, &kprefix, &kaddress, &kformat);
+		for (j = 0; j < count; j++) {
+			if (ktype != kprobes[j].type)
+				continue;
+			if (kprobes[j].event)
+				ename = kprobes[j].event;
+			else
+				ename = kprobes[j].address;
+			if (strcmp(ename, kevent))
+				continue;
+			if (kprobes[j].system) {
+				CU_TEST(strcmp(kprobes[j].system, ksystem) == 0);
+			} else {
+				CU_TEST(strcmp(KPROBE_DEFAULT_GROUP, ksystem) == 0);
+			}
+			CU_TEST(strcmp(kprobes[j].address, kaddress) == 0);
+			if (kprobes[j].format) {
+				CU_TEST(strcmp(kprobes[j].format, kformat) == 0);
+			}
+			if (kprobes[j].prefix) {
+				CU_TEST(strcmp(kprobes[j].prefix, kprefix) == 0);
+			}
+			ret = tracefs_event_enable(test_instance, ksystem, kevent);
+			if (in_system) {
+				CU_TEST(ret == 0);
+			} else {
+				CU_TEST(ret != 0);
+			}
+			ret = tracefs_event_disable(test_instance, ksystem, kevent);
+			if (in_system) {
+				CU_TEST(ret == 0);
+			} else {
+				CU_TEST(ret != 0);
+			}
+
+			found++;
+			break;
+		}
+		free(ksystem);
+		free(kevent);
+		free(kprefix);
+		free(kaddress);
+		free(kformat);
+	}
+
+	CU_TEST(found == count);
+	if (found != count)
+		return false;
+
+	return true;
+}
+
+static struct tracefs_dynevent **get_kprobes_check(enum tracefs_kprobe_type type, int count)
+{
+	struct tracefs_dynevent **devents;
+	int i;
+
+	devents = tracefs_kprobes_get(type);
+	if (count) {
+		CU_TEST(devents != NULL);
+		i = 0;
+		while (devents[i])
+			i++;
+		CU_TEST(i == count);
+	} else {
+		CU_TEST(devents == NULL);
+	}
+
+	return devents;
+}
+
+#define KPROBE_COUNT	3
+#define KRETPROBE_COUNT	2
+static void test_kprobes(void)
+{
+	struct kprobe_test ktests[KPROBE_COUNT] = {
+		{ TRACEFS_KPROBE, "p", NULL, "mkdir", "do_mkdirat", "path=+u0($arg2):ustring" },
+		{ TRACEFS_KPROBE, "p", NULL, "close", "close_fd", NULL },
+		{ TRACEFS_KPROBE, "p", "ptest", "open2", "do_sys_openat2",
+				  "file=+u0($arg2):ustring flags=+0($arg3):x64" },
+	};
+	struct kprobe_test kretests[KRETPROBE_COUNT] = {
+		{ TRACEFS_KRETPROBE, NULL, NULL, "retopen", "do_sys_openat2", "ret=$retval" },
+		{ TRACEFS_KRETPROBE, NULL, NULL, NULL, "do_sys_open", "ret=$retval" },
+	};
+	struct tracefs_dynevent *dkretprobe[KRETPROBE_COUNT + 1];
+	struct tracefs_dynevent *dkprobe[KPROBE_COUNT + 1];
+	struct tracefs_dynevent **devents;
+	char *tmp;
+	int ret;
+	int i;
+
+	/* Invalid parameters */
+	CU_TEST(tracefs_kprobe_alloc("test", NULL, NULL, "test") == NULL);
+	CU_TEST(tracefs_kretprobe_alloc("test", NULL, NULL, "test", 0) == NULL);
+	CU_TEST(tracefs_kprobe_create(NULL) != 0);
+	CU_TEST(tracefs_kprobe_info(NULL, &tmp, &tmp, &tmp, &tmp, &tmp) == TRACEFS_ALL_KPROBES);
+	CU_TEST(tracefs_kprobe_raw("test", "test", NULL, "test") != 0);
+	CU_TEST(tracefs_kretprobe_raw("test", "test", NULL, "test") != 0);
+	CU_TEST(tracefs_kprobe_raw("test", "test", "test", NULL) != 0);
+	CU_TEST(tracefs_kretprobe_raw("test", "test", "test", NULL) != 0);
+
+	/* kprobes APIs */
+	ret = tracefs_kprobe_destroy(NULL, true);
+	CU_TEST(ret == 0);
+	get_kprobes_check(TRACEFS_ALL_KPROBES, 0);
+
+	for (i = 0; i < KPROBE_COUNT; i++) {
+		dkprobe[i] = tracefs_kprobe_alloc(ktests[i].system, ktests[i].event,
+						  ktests[i].address, ktests[i].format);
+		CU_TEST(dkprobe[i] != NULL);
+	}
+	dkprobe[i] = NULL;
+	get_kprobes_check(TRACEFS_ALL_KPROBES, 0);
+	CU_TEST(check_kprobes(ktests, KPROBE_COUNT, dkprobe, false));
+
+	for (i = 0; i < KRETPROBE_COUNT; i++) {
+		dkretprobe[i] = tracefs_kretprobe_alloc(kretests[i].system, kretests[i].event,
+							kretests[i].address, kretests[i].format, 0);
+		CU_TEST(dkretprobe[i] != NULL);
+	}
+	dkretprobe[i] = NULL;
+	get_kprobes_check(TRACEFS_ALL_KPROBES, 0);
+	CU_TEST(check_kprobes(kretests, KRETPROBE_COUNT, dkretprobe, false));
+
+	for (i = 0; i < KPROBE_COUNT; i++) {
+		CU_TEST(tracefs_kprobe_create(dkprobe[i]) == 0);
+	}
+	devents = get_kprobes_check(TRACEFS_ALL_KPROBES, KPROBE_COUNT);
+	CU_TEST(check_kprobes(ktests, KPROBE_COUNT, devents, true));
+	CU_TEST(check_kprobes(kretests, KRETPROBE_COUNT, dkretprobe, false));
+	tracefs_dynevent_list_free(devents);
+	devents = NULL;
+
+	for (i = 0; i < KRETPROBE_COUNT; i++) {
+		CU_TEST(tracefs_kprobe_create(dkretprobe[i]) == 0);
+	}
+	devents = get_kprobes_check(TRACEFS_ALL_KPROBES, KPROBE_COUNT + KRETPROBE_COUNT);
+	CU_TEST(check_kprobes(ktests, KPROBE_COUNT, devents, true));
+	CU_TEST(check_kprobes(kretests, KRETPROBE_COUNT, devents, true));
+	tracefs_dynevent_list_free(devents);
+	devents = NULL;
+
+	for (i = 0; i < KRETPROBE_COUNT; i++) {
+		CU_TEST(tracefs_kprobe_destroy(dkretprobe[i], false) == 0);
+	}
+	devents = get_kprobes_check(TRACEFS_ALL_KPROBES, KPROBE_COUNT);
+	CU_TEST(check_kprobes(ktests, KPROBE_COUNT, devents, true));
+	CU_TEST(check_kprobes(kretests, KRETPROBE_COUNT, dkretprobe, false));
+	tracefs_dynevent_list_free(devents);
+	devents = NULL;
+
+	for (i = 0; i < KPROBE_COUNT; i++) {
+		CU_TEST(tracefs_kprobe_destroy(dkprobe[i], false) == 0);
+	}
+	get_kprobes_check(TRACEFS_ALL_KPROBES, 0);
+	CU_TEST(check_kprobes(ktests, KPROBE_COUNT, dkprobe, false));
+	CU_TEST(check_kprobes(kretests, KRETPROBE_COUNT, dkretprobe, false));
+	tracefs_dynevent_list_free(devents);
+	devents = NULL;
+
+	for (i = 0; i < KPROBE_COUNT; i++)
+		tracefs_kprobe_free(dkprobe[i]);
+	for (i = 0; i < KRETPROBE_COUNT; i++)
+		tracefs_kprobe_free(dkretprobe[i]);
+
+	/* kprobes raw APIs */
+	ret = tracefs_kprobe_destroy(NULL, true);
+	CU_TEST(ret == 0);
+	get_kprobes_check(TRACEFS_ALL_KPROBES, 0);
+
+	for (i = 0; i < KPROBE_COUNT; i++) {
+		ret = tracefs_kprobe_raw(ktests[i].system, ktests[i].event,
+					 ktests[i].address, ktests[i].format);
+		CU_TEST(ret == 0);
+	}
+
+	devents = get_kprobes_check(TRACEFS_KPROBE, KPROBE_COUNT);
+	CU_TEST(check_kprobes(ktests, KPROBE_COUNT, devents, true));
+	tracefs_dynevent_list_free(devents);
+	devents = NULL;
+
+	for (i = 0; i < KRETPROBE_COUNT; i++) {
+		ret = tracefs_kretprobe_raw(kretests[i].system, kretests[i].event,
+					    kretests[i].address, kretests[i].format);
+		CU_TEST(ret == 0);
+	}
+
+	devents = get_kprobes_check(TRACEFS_KPROBE, KPROBE_COUNT);
+	CU_TEST(check_kprobes(ktests, KPROBE_COUNT, devents, true));
+	tracefs_dynevent_list_free(devents);
+	devents = NULL;
+
+	devents = get_kprobes_check(TRACEFS_KRETPROBE, KRETPROBE_COUNT);
+	CU_TEST(check_kprobes(kretests, KRETPROBE_COUNT, devents, true));
+	tracefs_dynevent_list_free(devents);
+	devents = NULL;
+
+	devents = get_kprobes_check(TRACEFS_ALL_KPROBES, KPROBE_COUNT + KRETPROBE_COUNT);
+	CU_TEST(check_kprobes(ktests, KPROBE_COUNT, devents, true));
+	CU_TEST(check_kprobes(kretests, KRETPROBE_COUNT, devents, true));
+	tracefs_dynevent_list_free(devents);
+	devents = NULL;
+
+	ret = tracefs_kprobe_destroy(NULL, true);
+	CU_TEST(ret == 0);
+	get_kprobes_check(TRACEFS_ALL_KPROBES, 0);
+}
+
 static void test_instance_file(void)
 {
 	struct tracefs_instance *instance = NULL;
 	struct tracefs_instance *second = NULL;
-	enum tracefs_kprobe_type type;
 	const char *name = get_rand_str();
 	const char *inst_name = NULL;
 	const char *tdir;
 	char *inst_file;
 	char *inst_dir;
 	struct stat st;
-	char **kprobes;
-	char *kformat;
-	char *ktype;
-	char *kaddr;
-	char *fname;
 	char *file1;
 	char *file2;
 	char *tracer;
+	char *fname;
 	int size;
 	int ret;
-	int i;
 
 	tdir  = tracefs_tracing_dir();
 	CU_TEST(tdir != NULL);
@@ -541,153 +755,6 @@ static void test_instance_file(void)
 	free(file1);
 	free(file2);
 
-	ret = tracefs_kprobe_clear_all(true);
-	CU_TEST(ret == 0);
-	ret = tracefs_kprobe_raw(NULL, KPROBE_1_NAME, KPROBE_1_ADDR, KPROBE_1_FMT);
-	CU_TEST(ret == 0);
-	ret = tracefs_kprobe_raw(KPROBE_2_GROUP, KPROBE_2_NAME, KPROBE_2_ADDR,
-				 KPROBE_2_FMT);
-	CU_TEST(ret == 0);
-
-	ret = tracefs_kretprobe_raw(KPROBE_2_GROUP, KRETPROBE_NAME, KRETPROBE_ADDR,
-				 KRETPROBE_FMT);
-	CU_TEST(ret == 0);
-
-	type = tracefs_kprobe_info(KPROBE_1_GROUP, KPROBE_1_NAME, &ktype,
-				   &kaddr, &kformat);
-	CU_TEST(type == TRACEFS_KPROBE);
-	CU_TEST(ktype && *ktype == 'p');
-	CU_TEST(kaddr && !strcmp(kaddr, KPROBE_1_ADDR));
-	CU_TEST(kformat && !strcmp(kformat, KPROBE_1_FMT));
-	free(ktype);
-	free(kaddr);
-	free(kformat);
-
-	type = tracefs_kprobe_info(KPROBE_2_GROUP, KPROBE_2_NAME, &ktype,
-				   &kaddr, &kformat);
-	CU_TEST(type == TRACEFS_KPROBE);
-	CU_TEST(ktype && *ktype == 'p');
-	CU_TEST(kaddr && !strcmp(kaddr, KPROBE_2_ADDR));
-	CU_TEST(kformat && !strcmp(kformat, KPROBE_2_FMT));
-	free(ktype);
-	free(kaddr);
-	free(kformat);
-
-	type = tracefs_kprobe_info(KPROBE_2_GROUP, KRETPROBE_NAME, &ktype,
-				   &kaddr, &kformat);
-	CU_TEST(type == TRACEFS_KRETPROBE);
-	CU_TEST(ktype && *ktype == 'r');
-	CU_TEST(kaddr && !strcmp(kaddr, KRETPROBE_ADDR));
-	CU_TEST(kformat && !strcmp(kformat, KRETPROBE_FMT));
-	free(ktype);
-	free(kaddr);
-	free(kformat);
-
-	kprobes = tracefs_kprobes_get(TRACEFS_ALL_KPROBES);
-	CU_TEST(kprobes != NULL);
-
-	for (i = 0; kprobes[i]; i++) {
-		char *system = strtok(kprobes[i], "/");
-		char *event = strtok(NULL, "");
-		bool found = false;
-		if (!strcmp(system, KPROBE_1_GROUP)) {
-			CU_TEST(!strcmp(event, KPROBE_1_NAME));
-			found = true;
-		} else if (!strcmp(system, KPROBE_2_GROUP)) {
-			switch (tracefs_kprobe_info(system, event, NULL, NULL, NULL)) {
-			case TRACEFS_KPROBE:
-				CU_TEST(!strcmp(event, KPROBE_2_NAME));
-				found = true;
-				break;
-			case TRACEFS_KRETPROBE:
-				CU_TEST(!strcmp(event, KRETPROBE_NAME));
-				found = true;
-				break;
-			default:
-				break;
-			}
-		}
-		CU_TEST(found);
-	}
-	tracefs_list_free(kprobes);
-	CU_TEST(i == 3);
-
-	kprobes = tracefs_kprobes_get(TRACEFS_KPROBE);
-	CU_TEST(kprobes != NULL);
-
-	for (i = 0; kprobes[i]; i++) {
-		char *system = strtok(kprobes[i], "/");
-		char *event = strtok(NULL, "");
-		bool found = false;
-		if (!strcmp(system, KPROBE_1_GROUP)) {
-			CU_TEST(!strcmp(event, KPROBE_1_NAME));
-			found = true;
-		} else if (!strcmp(system, KPROBE_2_GROUP)) {
-			CU_TEST(!strcmp(event, KPROBE_2_NAME));
-			found = true;
-		}
-		CU_TEST(found);
-	}
-	tracefs_list_free(kprobes);
-	CU_TEST(i == 2);
-
-	kprobes = tracefs_kprobes_get(TRACEFS_KRETPROBE);
-	CU_TEST(kprobes != NULL);
-
-	for (i = 0; kprobes[i]; i++) {
-		char *system = strtok(kprobes[i], "/");
-		char *event = strtok(NULL, "");
-		bool found = false;
-		if (!strcmp(system, KPROBE_2_GROUP)) {
-			CU_TEST(!strcmp(event, KRETPROBE_NAME));
-			found = true;
-		}
-		CU_TEST(found);
-	}
-	tracefs_list_free(kprobes);
-	CU_TEST(i == 1);
-
-	ret = tracefs_event_enable(instance, KPROBE_1_GROUP, KPROBE_1_NAME);
-	CU_TEST(ret == 0);
-	ret = tracefs_event_enable(instance, KPROBE_2_GROUP, KPROBE_2_NAME);
-	CU_TEST(ret == 0);
-	ret = tracefs_event_enable(instance, KPROBE_2_GROUP, KRETPROBE_NAME);
-	CU_TEST(ret == 0);
-
-	ret = tracefs_kprobe_clear_all(false);
-	CU_TEST(ret < 0);
-
-	ret = tracefs_kprobe_clear_probe(KPROBE_2_GROUP, NULL, false);
-	CU_TEST(ret < 0);
-
-	ret = tracefs_kprobe_clear_probe(KPROBE_2_GROUP, NULL, true);
-	CU_TEST(ret == 0);
-
-	kprobes = tracefs_kprobes_get(TRACEFS_ALL_KPROBES);
-	CU_TEST(kprobes != NULL);
-
-	for (i = 0; kprobes[i]; i++) {
-		char *system = strtok(kprobes[i], "/");
-		char *event = strtok(NULL, "");
-		bool found = false;
-		if (!strcmp(system, KPROBE_1_GROUP)) {
-			CU_TEST(!strcmp(event, KPROBE_1_NAME));
-			found = true;
-		}
-		CU_TEST(found);
-	}
-	tracefs_list_free(kprobes);
-	CU_TEST(i == 1);
-
-	ret = tracefs_kprobe_clear_all(true);
-	CU_TEST(ret == 0);
-
-	kprobes = tracefs_kprobes_get(TRACEFS_ALL_KPROBES);
-	CU_TEST(kprobes != NULL);
-
-	CU_TEST(kprobes[0] == NULL);
-	tracefs_list_free(kprobes);
-
 	tracefs_put_tracing_file(inst_file);
 	free(fname);
 
@@ -1442,4 +1509,5 @@ void test_tracefs_lib(void)
 		    test_custom_trace_dir);
 	CU_add_test(suite, "ftrace marker",
 		    test_ftrace_marker);
+	CU_add_test(suite, "kprobes", test_kprobes);
 }
-- 
2.31.1

[PATCH v2 09/12] libtracefs: Update kprobes man pages

[Tzvetomir Stoyanov (VMware)]

As there are a lot of changes in the libtracefs kprobes APIs, the
documentation of the library should be updated.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 Documentation/libtracefs-kprobes.txt | 131 +++++++++++++++------------
 Documentation/libtracefs.txt         |  11 +++
 2 files changed, 86 insertions(+), 56 deletions(-)

diff --git a/Documentation/libtracefs-kprobes.txt b/Documentation/libtracefs-kprobes.txt
index ca48fa9..df9f2fa 100644
--- a/Documentation/libtracefs-kprobes.txt
+++ b/Documentation/libtracefs-kprobes.txt
@@ -3,7 +3,10 @@ libtracefs(3)
 
 NAME
 ----
-tracefs_kprobe_raw, tracefs_kretprobe_raw, tracefs_kprobes_get, tracefs_kprobe_info, tracefs_kprobe_clear_all, tracefs_kprobe_clear_probe - Create, list, and destroy kprobes
+tracefs_kprobe_alloc, tracefs_kretprobe_alloc, tracefs_kprobe_create,
+tracefs_kprobe_destroy, tracefs_kprobe_free, tracefs_kprobes_get,
+tracefs_kprobe_info, tracefs_kprobe_raw, tracefs_kretprobe_raw - Create, get, and destroy kprobes
+
 
 SYNOPSIS
 --------
@@ -11,18 +14,64 @@ SYNOPSIS
 --
 *#include <tracefs.h>*
 
-int tracefs_kprobe_raw(const char pass:[*]system, const char pass:[*]event, const char pass:[*]addr, const char pass:[*]format);
-int tracefs_kretprobe_raw(const char pass:[*]system, const char pass:[*]event, const char pass:[*]addr, const char pass:[*]format);
-char pass:[*]pass:[*]tracefs_kprobes_get(enum tracefs_kprobe_type type);
-enum tracefs_kprobe_type tracefs_kprobe_info(const char pass:[*]group, const char pass:[*]event,
-					     char pass:[*]pass:[*]type, char pass:[*]pass:[*]addr, char pass:[*]pass:[*]format);
-enum tracefs_kprobe_type tracefs_kprobe_type(const char pass:[*]group, const char pass:[*]event)
-int tracefs_kprobe_clear_all(bool force);
-int tracefs_kprobe_clear_probe(const char pass:[*]system, const char pass:[*]event, bool force);
+struct tracefs_dynevent pass:[*]
+*tracefs_kprobe_alloc*(const char pass:[*]_system_, const char pass:[*]_event_,
+		       const char pass:[*]_addr_, const char pass:[*]_format_);
+struct tracefs_dynevent pass:[*]
+*tracefs_kretprobe_alloc*(const char pass:[*]_system_, const char pass:[*]_event_,
+			  const char pass:[*]_addr_, const char pass:[*]_format_, int _max_);
+void *tracefs_kprobe_free*(struct tracefs_dynevent pass:[*]_kprobe_);
+int *tracefs_kprobe_create*(struct tracefs_dynevent pass:[*]_kprobe_);
+int *tracefs_kprobe_destroy*(struct tracefs_dynevent pass:[*]_kprobe_, bool _force_);
+struct tracefs_dynevent pass:[*]pass:[*]*tracefs_kprobes_get*(enum tracefs_kprobe_type _type_);
+enum tracefs_kprobe_type *tracefs_kprobe_info*(struct tracefs_dynevent pass:[*]_kprobe_,
+					       char pass:[*]pass:[*]_system_, char pass:[*]pass:[*]_event_,
+					       char pass:[*]pass:[*]_prefix_, char pass:[*]pass:[*]_addr_,
+					       char pass:[*]pass:[*]_format_);
+int *tracefs_kprobe_raw*(const char pass:[*]_system_, const char pass:[*]_event_,
+			 const char pass:[*]_addr_, const char pass:[*]_format_);
+int *tracefs_kretprobe_raw*(const char pass:[*]_system_, const char pass:[*]_event_,
+			    const char pass:[*]_addr_, const char pass:[*]_format_);
 --
 
 DESCRIPTION
 -----------
+*tracefs_kprobe_alloc*() allocates a new kprobe context. The kbrobe is not configured in the system.
+The new kprobe will be in the _system_ group (or kprobes if _system_ is NULL). Have the name of
+_event_ (or _addr_ if _event_ is NULL). Will be inserted to _addr_ (function name, with or without
+offset, or a address). And the _format_ will define the format of the kprobe. See the Linux
+documentation file under: Documentation/trace/kprobetrace.rst
+
+*tracefs_kretprobe_alloc*() is the same as *tracefs_kprobe_alloc*, but allocates context for
+kretprobe. It has one additional parameter, which is optional, _max_ - maxactive count.
+See description of kretprobes in the Documentation/trace/kprobetrace.rst file.
+
+*tracefs_kprobe_free*() frees a kprobe context, allocated with *tracefs_kprobe_alloc*() or
+*tracefs_kretprobe_alloc*(). The kprobe is not removed from the system.
+
+*tracefs_kprobe_create*() creates a kprobe or kretprobe in the system. The probe is described by the
+given _kprobe_ context.
+
+*tracefs_kprobe_destroy*() will try to remove the specified _kprobe_ from the system. If _kprobe_
+is NULL, all kprobes and kretprobes in the system will be removed. If the _force_ flag is set, then
+it will disable the given kprobe events before removing them.
+
+*tracefs_kprobes_get*() return an array of pointers to kprobes and kretprobes in the system,
+depending on the given _type_. If _type_ is TRACEFS_ALL_KPROBES, then all kprobes found are
+returned. If _type_ is TRACEFS_KPROBE, then only normal kprobes are returned. If _type_ is
+TRACEFS_KRETPROBE, then only kretprobes are returned. The last element of the returned array is
+a NULL pointer. The array must be freed with *tracefs_dynevent_list_free*(3).
+
+*tracefs_kprobe_info*() returns the type and information of a given _kprobe_. If any of the
+_system_, _event_, _prefix_, _addr_ or _format_ arguments are not NULL, then strings are allocated
+and returned back via these arguments. The _system_ and _event_ holds the system and the name of the
+kprobe. If _prefix_ is non NULL, then it will hold an allocated string that holds the prefix portion
+of the kprobe in the kprobe_events file (the content up to the ":", including it). Note that for
+kretprobes, the max active count is encoded in the prefix srting. If _addr_ is non NULL, it will
+hold the address or function that the kprobe is attached to. If _format_ is non NULL, it will hold
+the format string of the kprobe. Note, that the content in _group_, _event_, _prefix_, _addr_, and
+_format_ must be freed with free(3) if they are set.
+
 *tracefs_kprobe_raw*() will create a kprobe event. If _system_ is NULL, then
 the default "kprobes" is used for the group (event system). Otherwise if _system_
 is specified then the kprobe will be created under the group by that name. The
@@ -36,55 +85,24 @@ document.
 creates a kretprobe instead of a kprobe. The difference is also described
 in the Linux kernel source in the Documentation/trace/kprobetrace.rst file.
 
-*tracefs_kprobes_get*() returns an array of strings (char pass:[*]) that contain
-the registered kprobes and kretprobes depending on the given _type_. If _type_ is
-TRACEFS_ALL_KPROBES, then all kprobes found are returned. If _type_ is
-TRACEFS_KPROBE, then only normal kprobes are returned. If _type_ is
-TRACEFS_KRETPROBE, then only kretprobes are returned.
-The names are in the "system/event" format.
-That is, one string holds both the kprobe's name as well as the group it is
-defined under. These strings are allocated and may be modified with the
-*strtok*(3) and *strtok_r*(3) functions. The string returned must be freed with
-*tracefs_list_free*(3).
-
-*tracefs_kprobe_info*() returns the type of the given kprobe. If _group_ is
-NULL, then the default "kprobes" is used. If _type_ is non NULL, then it will
-hold an allocated string that holds the type portion of the kprobe in the
-kprobe_events file (the content before the ":"). If _addr_ is non NULL, it will
-hold the address or function that the kprobe is attached to. If _format_ is non
-NULL, it will hold the format string of the kprobe. Note, that the content in
-_type_, _addr_, and _format_ must be freed with free(3) if they are set. Even
-in the case of an error, as they may hold information of what caused the error.
-
-*tracefs_kprobe_clear_all*() will try to remove all kprobes that have been
-registered. If the @force flag is set, it will then disable those kprobe events
-if they are enabled and then try to clear the kprobes.
-
-*tracefs_kprobe_clear_probe*() will try to clear specified kprobes. If _system_
-is NULL, then it will only clear the default kprobes under the "kprobes" group.
-If _event_ is NULL, it will clear all kprobes under the given _system_. If the
-_force_ flag is set, then it will disable the given kprobe events before clearing
-them.
-
 RETURN VALUE
 ------------
 
-*tracefs_kprobe_raw*(), *tracefs_kretprobe_raw*(), *tracefs_kprobe_clear_all*(),
-and *tracefs_kprobe_clear_probe*() return 0 on success, or -1 on error.
+*tracefs_kprobe_raw*(), *tracefs_kretprobe_raw*(), *tracefs_kprobe_create*(),
+and *tracefs_kprobe_destroy*() return 0 on success, or -1 on error.
 
-If a parsing error occurs on *tracefs_kprobe_raw*() or *tracefs_kretprobe_raw*()
-then *tracefs_error_last*(3) may be used to retrieve the error message explaining
-the parsing issue.
+If a parsing error occurs on *tracefs_kprobe_raw*(), *tracefs_kretprobe_raw*() or
+*tracefs_kprobe_create*() then *tracefs_error_last*(3) may be used to retrieve the error message
+explaining the parsing issue.
 
-*tracefs_kprobes_get*() returns an allocate string list of allocated strings
-on success that must be freed with *tracefs_list_free*(3) and returns
-NULL on error.
+*tracefs_kprobes_get*() return an array of pointers to kprobes of the requested types, or NULL in
+case of an error. The last element is a NULL pointer. The array must be freed with
+*tracefs_dynevent_list_free*(3).
 
-*tracefs_kprobe_info*() returns the type of the given kprobe. It returns
-TRACEFS_KPROBE for normal kprobes, TRACEFS_KRETPROBE for kretprobes, and
-on error, or if the kprobe is not found TRACEFS_ALL_KPROBES is returned.
-If _type_, _addr_, or _format_ are non NULL, they will contain allocated
-strings that must be freed by free(3) even in the case of error.
+*tracefs_kprobe_info*() returns the type of the given kprobe. It returns TRACEFS_KPROBE for normal
+kprobes, TRACEFS_KRETPROBE for kretprobes or TRACEFS_ALL_KPROBES on error. If _system_, _event_,
+_prefix_, _addr_, or _format_ are non NULL, they will contain allocated strings that must be freed
+by free(3).
 
 ERRORS
 ------
@@ -96,7 +114,8 @@ The following errors are for all the above calls:
 
 *ENOMEM* Memory allocation error.
 
-*tracefs_kprobe_raw*(), *tracefs_kretprobe_raw*() can fail with the following errors:
+*tracefs_kprobe_raw*(), *tracefs_kretprobe_raw*(), *tracefs_kprobe_alloc*(),
+*tracefs_kretprobe_alloc*() and *tracefs_kprobe_create*() can fail with the following errors:
 
 *EBADMSG* Either _addr_ or _format_ are NULL.
 
@@ -217,7 +236,7 @@ int main (int argc, char **argv, char **env)
 		exit(-1);
 	}
 
-	tracefs_kprobe_clear_probe(mykprobe, NULL, true);
+	tracefs_kprobe_destroy(NULL, true);
 
 	kprobe_create("open", "do_sys_openat2",
 		      "file=+0($arg2):ustring flags=+0($arg3):x64 mode=+8($arg3):x64\n");
@@ -247,7 +266,7 @@ int main (int argc, char **argv, char **env)
 	} while (waitpid(pid, NULL, WNOHANG) != pid);
 
 	/* Will disable the events */
-	tracefs_kprobe_clear_probe(mykprobe, NULL, true);
+	tracefs_kprobe_destroy(NULL, true);
 	tracefs_instance_destroy(instance);
 	tep_free(tep);
 
@@ -293,5 +312,5 @@ https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git/
 
 COPYING
 -------
-Copyright \(C) 2020 VMware, Inc. Free use of this software is granted under
+Copyright \(C) 2021 VMware, Inc. Free use of this software is granted under
 the terms of the GNU Public License (GPL).
diff --git a/Documentation/libtracefs.txt b/Documentation/libtracefs.txt
index 2c9eabd..4a356c8 100644
--- a/Documentation/libtracefs.txt
+++ b/Documentation/libtracefs.txt
@@ -63,6 +63,17 @@ Writing data in the trace buffer:
 
 Control library logs:
 	int *tracefs_set_loglevel*(enum tep_loglevel _level_);
+
+Kprobes and Kretprobes:
+	struct tracefs_dynevent pass:[*] *tracefs_kprobe_alloc*(const char pass:[*]_system_, const char pass:[*]_event_, const char pass:[*]_addr_, const char pass:[*]_format_);
+	struct tracefs_dynevent pass:[*] *tracefs_kretprobe_alloc*(const char pass:[*]_system_, const char pass:[*]_event_, const char pass:[*]_addr_, const char pass:[*]_format_, int _max_);
+	void *tracefs_kprobe_free*(struct tracefs_dynevent pass:[*]_kprobe_);
+	int *tracefs_kprobe_create*(struct tracefs_dynevent pass:[*]_kprobe_);
+	int *tracefs_kprobe_destroy*(struct tracefs_dynevent pass:[*]_kprobe_, bool _force_);
+	struct tracefs_dynevent pass:[*]pass:[*]*tracefs_kprobes_get*(enum tracefs_kprobe_type _type_);
+	enum tracefs_kprobe_type *tracefs_kprobe_info*(struct tracefs_dynevent pass:[*]_kprobe_, char pass:[*]pass:[*]_system_, char pass:[*]pass:[*]_event_, char pass:[*]pass:[*]_prefix_, char pass:[*]pass:[*]_addr_, char pass:[*]pass:[*]_format_);
+	int *tracefs_kprobe_raw*(const char pass:[*]_system_, const char pass:[*]_event_, const char pass:[*]_addr_, const char pass:[*]_format_);
+	int *tracefs_kretprobe_raw*(const char pass:[*]_system_, const char pass:[*]_event_, const char pass:[*]_addr_, const char pass:[*]_format_);
 --
 
 DESCRIPTION
-- 
2.31.1

[PATCH v2 10/12] libtracefs: Rename tracefs_synth_init API

[Tzvetomir Stoyanov (VMware)]

In order to be consistent with the others library APIs, the
tracefs_synth_init() is renamed to tracefs_synth_alloc().

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 Documentation/libtracefs-synth.txt  | 20 ++++++++++----------
 Documentation/libtracefs-synth2.txt | 10 +++++-----
 include/tracefs.h                   | 18 +++++++++---------
 src/tracefs-hist.c                  | 22 +++++++++++-----------
 src/tracefs-sqlhist.c               |  6 +++---
 5 files changed, 38 insertions(+), 38 deletions(-)

diff --git a/Documentation/libtracefs-synth.txt b/Documentation/libtracefs-synth.txt
index 77076e1..2fd9019 100644
--- a/Documentation/libtracefs-synth.txt
+++ b/Documentation/libtracefs-synth.txt
@@ -3,7 +3,7 @@ libtracefs(3)
 
 NAME
 ----
-tracefs_synth_init, tracefs_synth_add_match_field, tracefs_synth_add_compare_field, tracefs_synth_add_start_field,
+tracefs_synth_alloc, tracefs_synth_add_match_field, tracefs_synth_add_compare_field, tracefs_synth_add_start_field,
 tracefs_synth_add_end_field, tracefs_synth_append_start_filter, tracefs_synth_append_end_filter, tracefs_synth_free,
 - Creation of a synthetic event descriptor
 
@@ -13,7 +13,7 @@ SYNOPSIS
 --
 *#include <tracefs.h>*
 
-struct tracefs_synth pass:[*]tracefs_synth_init(struct tep_handle pass:[*]tep,
+struct tracefs_synth pass:[*]tracefs_synth_alloc(struct tep_handle pass:[*]tep,
 					 const char pass:[*]name,
 					 const char pass:[*]start_system,
 					 const char pass:[*]start_event,
@@ -69,7 +69,7 @@ as a field for both events to calculate the delta in nanoseconds, or use
 *TRACEFS_TIMESTAMP_USECS" as the compare fields for both events to calculate the
 delta in microseconds. This is used as the example below.
 
-*tracefs_synth_init*() allocates and initializes a synthetic event.
+*tracefs_synth_alloc*() allocates and initializes a synthetic event.
 It does not create the synthetic event, but supplies the minimal information
 to do so. See *tracefs_synth_create*(3) for how to create the synthetic
 event in the system. It requires a _tep_ handler that can be created by
@@ -156,11 +156,11 @@ _field_, _compare_, and _val_ are ignored unless _type_ is equal to
 filters on the ending event.
 
 *tracefs_synth_free*() frees the allocated descriptor returned by
-*tracefs_synth_init*().
+*tracefs_synth_alloc*().
 
 RETURN VALUE
 ------------
-*tracefs_synth_init*() returns an allocated struct tracefs_synth descriptor
+*tracefs_synth_alloc*() returns an allocated struct tracefs_synth descriptor
 on sucess or NULL on error.
 
 All other functions that return an integer returns zero on success or -1
@@ -209,11 +209,11 @@ static void make_event(void)
 	tep = tracefs_local_events(NULL);
 
 	/* Initialize the synthetic event */
-	synth = tracefs_synth_init(tep, "wakeup_lat",
-				   NULL, start_event,
-				   NULL, end_event,
-				   start_field, end_field,
-				   match_name);
+	synth = tracefs_synth_alloc(tep, "wakeup_lat",
+				    NULL, start_event,
+				    NULL, end_event,
+				    start_field, end_field,
+				    match_name);
 
 	/* The tep is no longer needed */
 	tep_free(tep);
diff --git a/Documentation/libtracefs-synth2.txt b/Documentation/libtracefs-synth2.txt
index 4c44253..f734b44 100644
--- a/Documentation/libtracefs-synth2.txt
+++ b/Documentation/libtracefs-synth2.txt
@@ -142,11 +142,11 @@ static void make_event(void)
 	tep = tracefs_local_events(NULL);
 
 	/* Initialize the synthetic event */
-	synth = tracefs_synth_init(tep, "wakeup_lat",
-				   NULL, start_event,
-				   NULL, end_event,
-				   start_field, end_field,
-				   match_name);
+	synth = tracefs_synth_alloc(tep, "wakeup_lat",
+				    NULL, start_event,
+				    NULL, end_event,
+				    start_field, end_field,
+				    match_name);
 
 	/* The tep is no longer needed */
 	tep_free(tep);
diff --git a/include/tracefs.h b/include/tracefs.h
index f75fd92..b203a40 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -472,15 +472,15 @@ enum tracefs_synth_handler {
 	TRACEFS_SYNTH_HANDLE_CHANGE,
 };
 
-struct tracefs_synth *tracefs_synth_init(struct tep_handle *tep,
-					 const char *name,
-					 const char *start_system,
-					 const char *start_event,
-					 const char *end_system,
-					 const char *end_event,
-					 const char *start_match_field,
-					 const char *end_match_field,
-					 const char *match_name);
+struct tracefs_synth *tracefs_synth_alloc(struct tep_handle *tep,
+					  const char *name,
+					  const char *start_system,
+					  const char *start_event,
+					  const char *end_system,
+					  const char *end_event,
+					  const char *start_match_field,
+					  const char *end_match_field,
+					  const char *match_name);
 int tracefs_synth_add_match_field(struct tracefs_synth *synth,
 				  const char *start_match_field,
 				  const char *end_match_field,
diff --git a/src/tracefs-hist.c b/src/tracefs-hist.c
index 27bab00..9009dba 100644
--- a/src/tracefs-hist.c
+++ b/src/tracefs-hist.c
@@ -692,7 +692,7 @@ static void action_free(struct action *action)
  * @synth: The tracefs_synth descriptor
  *
  * Frees the resources allocated for a @synth created with
- * tracefs_synth_init(). It does not touch the system. That is,
+ * tracefs_synth_alloc(). It does not touch the system. That is,
  * any synthetic event created, will not be destroyed by this
  * function.
  */
@@ -890,7 +890,7 @@ synth_init_from(struct tep_handle *tep, const char *start_system,
 }
 
 /**
- * tracefs_synth_init - create a new tracefs_synth instance
+ * tracefs_synth_alloc - create a new tracefs_synth instance
  * @tep: The tep handle that holds the events to work on
  * @name: The name of the synthetic event being created
  * @start_system: The name of the system of the start event (can be NULL)
@@ -933,15 +933,15 @@ synth_init_from(struct tep_handle *tep, const char *start_system,
  * event on the system is not created. That needs to be done with
  * tracefs_synth_create().
  */
-struct tracefs_synth *tracefs_synth_init(struct tep_handle *tep,
-					 const char *name,
-					 const char *start_system,
-					 const char *start_event_name,
-					 const char *end_system,
-					 const char *end_event_name,
-					 const char *start_match_field,
-					 const char *end_match_field,
-					 const char *match_name)
+struct tracefs_synth *tracefs_synth_alloc(struct tep_handle *tep,
+					  const char *name,
+					  const char *start_system,
+					  const char *start_event_name,
+					  const char *end_system,
+					  const char *end_event_name,
+					  const char *start_match_field,
+					  const char *end_match_field,
+					  const char *match_name)
 {
 	struct tep_event *end_event;
 	struct tracefs_synth *synth;
diff --git a/src/tracefs-sqlhist.c b/src/tracefs-sqlhist.c
index d77ce86..016f3eb 100644
--- a/src/tracefs-sqlhist.c
+++ b/src/tracefs-sqlhist.c
@@ -1419,9 +1419,9 @@ static struct tracefs_synth *build_synth(struct tep_handle *tep,
 	assign_match(start_system, start_event, match,
 		     &start_match, &end_match);
 
-	synth = tracefs_synth_init(tep, name, start_system,
-				   start_event, end_system, end_event,
-				   start_match, end_match, NULL);
+	synth = tracefs_synth_alloc(tep, name, start_system,
+				    start_event, end_system, end_event,
+				    start_match, end_match, NULL);
 	if (!synth)
 		return synth_init_error(tep, table);
 
-- 
2.31.1

[PATCH v2 11/12] libtracefs: Use the internal dynamic events API when creating synthetic events

[Tzvetomir Stoyanov (VMware)]

Synthetic events are type of ftrace dynamic events. The tracefs library
has an internal helper APIs to manage dynamic events of all types. In
order the code to be consistent, the creation of synthetic events inside
the library is reimplemented with these new dynamic events APIs.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 src/tracefs-hist.c | 88 +++++++++++++++++-----------------------------
 1 file changed, 33 insertions(+), 55 deletions(-)

diff --git a/src/tracefs-hist.c b/src/tracefs-hist.c
index 9009dba..7ac0023 100644
--- a/src/tracefs-hist.c
+++ b/src/tracefs-hist.c
@@ -661,6 +661,7 @@ struct tracefs_synth {
 	struct tep_event	*end_event;
 	struct action		*actions;
 	struct action		**next_action;
+	struct tracefs_dynevent	*dyn_event;
 	char			*name;
 	char			**synthetic_fields;
 	char			**synthetic_args;
@@ -719,6 +720,7 @@ void tracefs_synth_free(struct tracefs_synth *synth)
 		synth->actions = action->next;
 		action_free(action);
 	}
+	dynevent_free(synth->dyn_event);
 
 	free(synth);
 }
@@ -889,6 +891,28 @@ synth_init_from(struct tep_handle *tep, const char *start_system,
 	return synth;
 }
 
+static int alloc_synthetic_event(struct tracefs_synth *synth)
+{
+	char *synthetic_format;
+	const char *field;
+	int i;
+
+	synthetic_format = strdup("");
+	if (!synthetic_format)
+		return -1;
+
+	for (i = 0; synth->synthetic_fields && synth->synthetic_fields[i]; i++) {
+		field = synth->synthetic_fields[i];
+		synthetic_format = append_string(synthetic_format, " ", field);
+	}
+
+	synth->dyn_event = dynevent_alloc(TRACE_DYNEVENT_SYNTH, NULL,
+					  synth->name, NULL, synthetic_format);
+	free(synthetic_format);
+
+	return synth->dyn_event ? 0 : -1;
+}
+
 /**
  * tracefs_synth_alloc - create a new tracefs_synth instance
  * @tep: The tep handle that holds the events to work on
@@ -1609,38 +1633,6 @@ int tracefs_synth_save(struct tracefs_synth *synth,
 	return 0;
 }
 
-static char *create_synthetic_event(struct tracefs_synth *synth)
-{
-	char *synthetic_event;
-	const char *field;
-	int i;
-
-	synthetic_event = strdup(synth->name);
-	if (!synthetic_event)
-		return NULL;
-
-	for (i = 0; synth->synthetic_fields && synth->synthetic_fields[i]; i++) {
-		field = synth->synthetic_fields[i];
-		synthetic_event = append_string(synthetic_event, " ", field);
-	}
-
-	return synthetic_event;
-}
-
-static int remove_synthetic(const char *synthetic)
-{
-	char *str;
-	int ret;
-
-	ret = asprintf(&str, "!%s", synthetic);
-	if (ret < 0)
-		return -1;
-
-	ret = tracefs_instance_file_append(NULL, "synthetic_events", str);
-	free(str);
-	return ret < 0 ? -1 : 0;
-}
-
 static int remove_hist(struct tracefs_instance *instance,
 		       struct tep_event *event, const char *hist)
 {
@@ -1919,7 +1911,6 @@ tracefs_synth_get_start_hist(struct tracefs_synth *synth)
 int tracefs_synth_create(struct tracefs_instance *instance,
 			 struct tracefs_synth *synth)
 {
-	char *synthetic_event;
 	char *start_hist = NULL;
 	char *end_hist = NULL;
 	int ret;
@@ -1937,14 +1928,10 @@ int tracefs_synth_create(struct tracefs_instance *instance,
 	if (verify_state(synth) < 0)
 		return -1;
 
-	synthetic_event = create_synthetic_event(synth);
-	if (!synthetic_event)
+	if (!synth->dyn_event && alloc_synthetic_event(synth))
+		return -1;
+	if (!dynevent_create(synth->dyn_event))
 		return -1;
-
-	ret = tracefs_instance_file_append(NULL, "synthetic_events",
-					   synthetic_event);
-	if (ret < 0)
-		goto free_synthetic;
 
 	start_hist = create_hist(synth->start_keys, synth->start_vars);
 	start_hist = append_filter(start_hist, synth->start_filter,
@@ -1980,9 +1967,7 @@ int tracefs_synth_create(struct tracefs_instance *instance,
  remove_synthetic:
 	free(end_hist);
 	free(start_hist);
-	remove_synthetic(synthetic_event);
- free_synthetic:
-	free(synthetic_event);
+	dynevent_destroy(synth->dyn_event);
 	return -1;
 }
 
@@ -2007,7 +1992,6 @@ int tracefs_synth_create(struct tracefs_instance *instance,
 int tracefs_synth_destroy(struct tracefs_instance *instance,
 			  struct tracefs_synth *synth)
 {
-	char *synthetic_event;
 	char *hist;
 	int ret;
 
@@ -2041,11 +2025,7 @@ int tracefs_synth_destroy(struct tracefs_instance *instance,
 	ret = remove_hist(instance, synth->start_event, hist);
 	free(hist);
 
-	synthetic_event = create_synthetic_event(synth);
-	if (!synthetic_event)
-		return -1;
-
-	ret = remove_synthetic(synthetic_event);
+	ret = dynevent_destroy(synth->dyn_event);
 
 	return ret ? -1 : 0;
 }
@@ -2067,7 +2047,6 @@ int tracefs_synth_show(struct trace_seq *seq,
 		       struct tracefs_instance *instance,
 		       struct tracefs_synth *synth)
 {
-	char *synthetic_event = NULL;
 	char *hist = NULL;
 	char *path;
 	int ret = -1;
@@ -2082,16 +2061,16 @@ int tracefs_synth_show(struct trace_seq *seq,
 		return -1;
 	}
 
-	synthetic_event = create_synthetic_event(synth);
-	if (!synthetic_event)
+	if (!synth->dyn_event && alloc_synthetic_event(synth))
 		return -1;
 
 	path = trace_find_tracing_dir();
 	if (!path)
 		goto out_free;
 
-	trace_seq_printf(seq, "echo '%s' > %s/synthetic_events\n",
-			 synthetic_event, path);
+	trace_seq_printf(seq, "echo '%s%s %s' > %s/%s\n",
+			 synth->dyn_event->prefix, synth->dyn_event->event,
+			 synth->dyn_event->format, path, synth->dyn_event->trace_file);
 
 	tracefs_put_tracing_file(path);
 	path = tracefs_instance_get_dir(instance);
@@ -2118,7 +2097,6 @@ int tracefs_synth_show(struct trace_seq *seq,
 
 	ret = 0;
  out_free:
-	free(synthetic_event);
 	free(hist);
 	tracefs_put_tracing_file(path);
 	return ret;
-- 
2.31.1

[PATCH v2 12/12] libtracefs: Document tracefs_dynevent_list_free() API

[Tzvetomir Stoyanov (VMware)]

The newly added tracefs_dynevent_list_free() should be documented in the
library man pages.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 Documentation/libtracefs-utils.txt | 6 +++++-
 Documentation/libtracefs.txt       | 1 +
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/Documentation/libtracefs-utils.txt b/Documentation/libtracefs-utils.txt
index 41544ab..3424673 100644
--- a/Documentation/libtracefs-utils.txt
+++ b/Documentation/libtracefs-utils.txt
@@ -3,7 +3,7 @@ libtracefs(3)
 
 NAME
 ----
-tracefs_tracers, tracefs_get_clock, tracefs_list_free -
+tracefs_tracers, tracefs_get_clock, tracefs_list_free, tracefs_dynevent_list_free -
 Helper functions for working with trace file system.
 
 SYNOPSIS
@@ -15,6 +15,7 @@ SYNOPSIS
 char pass:[*]pass:[*]*tracefs_tracers*(const char pass:[*]_tracing_dir_);
 char pass:[*]*tracefs_get_clock*(struct tracefs_instance pass:[*]_instance_);
 void *tracefs_list_free*(char pass:[*]pass:[*]_list_);
+void *tracefs_dynevent_list_free*(struct tracefs_dynevent pass:[*]pass:[*]_events_);
 --
 
 DESCRIPTION
@@ -36,6 +37,9 @@ The _tracefs_list_free()_ function frees an array of strings, returned by
 _tracefs_event_systems()_, _tracefs_system_events()_ and _tracefs_tracers()_
 APIs.
 
+The _tracefs_dynevent_list_free()_ functions frees an array of pointers to dynamic event contexts,
+returned by_tracefs_kprobes_get()_ API.
+
 RETURN VALUE
 ------------
 The _tracefs_tracers()_ returns array of strings. The last element in that
diff --git a/Documentation/libtracefs.txt b/Documentation/libtracefs.txt
index 4a356c8..7889048 100644
--- a/Documentation/libtracefs.txt
+++ b/Documentation/libtracefs.txt
@@ -45,6 +45,7 @@ Trace helper functions:
 	void *tracefs_list_free*(char pass:[*]pass:[*]_list_);
 	char pass:[*]pass:[*]*tracefs_tracers*(const char pass:[*]_tracing_dir_);
 	char pass:[*]*tracefs_get_clock*(struct tracefs_instance pass:[*]_instance_);
+	void *tracefs_dynevent_list_free*(struct tracefs_dynevent pass:[*]pass:[*]_events_);
 	int *tracefs_trace_is_on*(struct tracefs_instance pass:[*]_instance_);
 	int *tracefs_trace_on*(struct tracefs_instance pass:[*]_instance_);
 	int *tracefs_trace_off*(struct tracefs_instance pass:[*]_instance_);
-- 
2.31.1

Re: [PATCH v2 00/12] libtracefs dynamic events support

[Tzvetomir Stoyanov]

On Mon, Nov 1, 2021 at 11:09 AM Tzvetomir Stoyanov (VMware)
<tz.stoyanov@gmail.com> wrote:
>
> The libtracefs logic that works with ftrace dynamic events is unified and
> capsulated into internal APIs. This change makes the code more consistent
> and reusable. Also, adding future libtracefs support for uprobes and
> eprobes dynamic events is simplified.
> The existing library APIs for kprobes and synthetic events are reimplemented
> using the new dynamic events helpers.
>

Forgot to add that this patch set depends on "[PATCH v2 0/4]
Modifications of some 'hist' APIs":
 https://lore.kernel.org/linux-trace-devel/20210924095702.151826-1-y.karadz@gmail.com/

> Suggested-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com>
>
> v2 changes:
>  - Removed triple pointer from the APIs.
>  - Reimplement dynamic events parsing using strtok_r instead of strchr.
>  - Coding style fixes.
>
> Tzvetomir Stoyanov (VMware) (12):
>   libtracefs: Add new internal APIs for dynamic events
>   libtracefs: Rename tracefs_get_kprobes API
>   libtracefs: New kprobes APIs
>   libtracefs: Remove redundant kprobes APIs
>   libtracefs: Reimplement tracefs_kprobes_get API
>   libtracefs: Change tracefs_kprobe_info API
>   libtracefs: Reimplement kprobe raw APIs
>   libtracefs: Extend kprobes unit test
>   libtracefs: Update kprobes man pages
>   libtracefs: Rename tracefs_synth_init API
>   libtracefs: Use the internal dynamic events API when creating
>     synthetic events
>   libtracefs: Document tracefs_dynevent_list_free() API
>
>  Documentation/libtracefs-kprobes.txt | 131 ++++---
>  Documentation/libtracefs-synth.txt   |  20 +-
>  Documentation/libtracefs-synth2.txt  |  10 +-
>  Documentation/libtracefs-utils.txt   |   6 +-
>  Documentation/libtracefs.txt         |  12 +
>  include/tracefs-local.h              |  35 ++
>  include/tracefs.h                    |  38 +-
>  src/Makefile                         |   1 +
>  src/tracefs-dynevents.c              | 492 ++++++++++++++++++++++++++
>  src/tracefs-hist.c                   | 110 +++---
>  src/tracefs-kprobes.c                | 508 +++++++++++++--------------
>  src/tracefs-sqlhist.c                |   6 +-
>  utest/tracefs-utest.c                | 408 ++++++++++++---------
>  13 files changed, 1187 insertions(+), 590 deletions(-)
>  create mode 100644 src/tracefs-dynevents.c
>
> --
> 2.31.1
>


-- 
Tzvetomir (Ceco) Stoyanov
VMware Open Source Technology Center