[PATCH V2 04/10] perf script: Add option to pass arguments to dlfilters

Adrian Hunter
2021-06-27T13:18:18Z

Add option --dlarg to pass arguments to dlfilters. The --dlarg option can
be repeated to pass more than 1 argument.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
tools/perf/Documentation/perf-dlfilter.txt | 10 +++--
tools/perf/Documentation/perf-script.txt | 4 ++
tools/perf/builtin-script.c | 35 ++++++++++++++++-
tools/perf/util/dlfilter.c | 45 ++++++++++++++++++----
tools/perf/util/dlfilter.h | 6 ++-
tools/perf/util/perf_dlfilter.h | 4 +-
6 files changed, 91 insertions(+), 13 deletions(-)

diff --git a/tools/perf/Documentation/perf-dlfilter.txt b/tools/perf/Documentation/perf-dlfilter.txt
index 8bc219f3eb83..5795ab3ca23b 100644
--- a/tools/perf/Documentation/perf-dlfilter.txt
+++ b/tools/perf/Documentation/perf-dlfilter.txt
@@ -9,13 +9,14 @@ object file
SYNOPSIS
--------
[verse]
-'perf script' [--dlfilter file.so ]
+'perf script' [--dlfilter file.so ] [ --dlarg arg ]...

DESCRIPTION
-----------

This option is used to process data through a custom filter provided by a
-dynamically loaded shared object file.
+dynamically loaded shared object file. Arguments can be passed using --dlarg
+and retrieved using perf_dlfilter_fns.args().

If 'file.so' does not contain "/", then it will be found either in the current
directory, or perf tools exec path which is ~/libexec/perf-core/dlfilters for
@@ -121,7 +122,8 @@ file is loaded. The functions can be called by 'filter_event' or
struct perf_dlfilter_fns {
const struct perf_dlfilter_al *(*resolve_ip)(void *ctx);
const struct perf_dlfilter_al *(*resolve_addr)(void *ctx);
- void *(*reserved[126])(void *);
+ char **(*args)(void *ctx, int *dlargc);
+ void *(*reserved[125])(void *);
};
----

@@ -129,6 +131,8 @@ struct perf_dlfilter_fns {

'resolve_addr' returns information about addr (if addr_correlates_sym).

+'args' returns arguments from --dlarg options.
+
The perf_dlfilter_al structure
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

diff --git a/tools/perf/Documentation/perf-script.txt b/tools/perf/Documentation/perf-script.txt
index d2705d6b9874..aa3a0b2c29a2 100644
--- a/tools/perf/Documentation/perf-script.txt
+++ b/tools/perf/Documentation/perf-script.txt
@@ -102,6 +102,10 @@ OPTIONS
Filter sample events using the given shared object file.
Refer linkperf:perf-dlfilter[1]

+--dlarg=<arg>::
+ Pass 'arg' as an argument to the dlfilter. --dlarg may be repeated
+ to add more arguments.
+
--list-dlfilters=::
Display a list of available dlfilters. Use with option -v (must come
before option --list-dlfilters) to show long descriptions.
diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 4ffba1dbc55d..2030936cc891 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -81,6 +81,8 @@ static struct perf_stat_config stat_config;
static int max_blocks;
static bool native_arch;
static struct dlfilter *dlfilter;
+static int dlargc;
+static char **dlargv;

unsigned int scripting_max_stack = PERF_MAX_STACK_DEPTH;

@@ -3175,6 +3177,34 @@ static int list_available_scripts(const struct option *opt __maybe_unused,
exit(0);
}

+static int add_dlarg(const struct option *opt __maybe_unused,
+ const char *s, int unset __maybe_unused)
+{
+ char *arg = strdup(s);
+ void *a;
+
+ if (!arg)
+ return -1;
+
+ a = realloc(dlargv, sizeof(dlargv[0]) * (dlargc + 1));
+ if (!a) {
+ free(arg);
+ return -1;
+ }
+
+ dlargv = a;
+ dlargv[dlargc++] = arg;
+
+ return 0;
+}
+
+static void free_dlarg(void)
+{
+ while (dlargc--)
+ free(dlargv[dlargc]);
+ free(dlargv);
+}
+
/*
* Some scripts specify the required events in their "xxx-record" file,
* this function will check if the events in perf.data match those
@@ -3639,6 +3669,8 @@ int cmd_script(int argc, const char **argv)
OPT_STRING('g', "gen-script", &generate_script_lang, "lang",
"generate perf-script.xx script in specified language"),
OPT_STRING(0, "dlfilter", &dlfilter_file, "file", "filter .so file name"),
+ OPT_CALLBACK(0, "dlarg", NULL, "argument", "filter argument",
+ add_dlarg),
OPT_STRING('i', "input", &input_name, "file", "input file name"),
OPT_BOOLEAN('d', "debug-mode", &debug_mode,
"do various checks like samples ordering and lost events"),
@@ -3958,7 +3990,7 @@ int cmd_script(int argc, const char **argv)
}

if (dlfilter_file) {
- dlfilter = dlfilter__new(dlfilter_file);
+ dlfilter = dlfilter__new(dlfilter_file, dlargc, dlargv);
if (!dlfilter)
return -1;
}
@@ -4116,6 +4148,7 @@ int cmd_script(int argc, const char **argv)
if (script_started)
cleanup_scripting();
dlfilter__cleanup(dlfilter);
+ free_dlarg();
out:
return err;
}
diff --git a/tools/perf/util/dlfilter.c b/tools/perf/util/dlfilter.c
index 288a2b57378c..eaa3cea49178 100644
--- a/tools/perf/util/dlfilter.c
+++ b/tools/perf/util/dlfilter.c
@@ -133,9 +133,26 @@ static const struct perf_dlfilter_al *dlfilter__resolve_addr(void *ctx)
return d_addr_al;
}

+static char **dlfilter__args(void *ctx, int *dlargc)
+{
+ struct dlfilter *d = (struct dlfilter *)ctx;
+
+ if (dlargc)
+ *dlargc = 0;
+ else
+ return NULL;
+
+ if (!d->ctx_valid && !d->in_start && !d->in_stop)
+ return NULL;
+
+ *dlargc = d->dlargc;
+ return d->dlargv;
+}
+
static const struct perf_dlfilter_fns perf_dlfilter_fns = {
.resolve_ip = dlfilter__resolve_ip,
.resolve_addr = dlfilter__resolve_addr,
+ .args = dlfilter__args,
};

static char *find_dlfilter(const char *file)
@@ -169,7 +186,7 @@ static char *find_dlfilter(const char *file)

#define CHECK_FLAG(x) BUILD_BUG_ON((u64)PERF_DLFILTER_FLAG_ ## x != (u64)PERF_IP_FLAG_ ## x)

-static int dlfilter__init(struct dlfilter *d, const char *file)
+static int dlfilter__init(struct dlfilter *d, const char *file, int dlargc, char **dlargv)
{
CHECK_FLAG(BRANCH);
CHECK_FLAG(CALL);
@@ -189,6 +206,8 @@ static int dlfilter__init(struct dlfilter *d, const char *file)
d->file = find_dlfilter(file);
if (!d->file)
return -1;
+ d->dlargc = dlargc;
+ d->dlargv = dlargv;
return 0;
}

@@ -219,14 +238,14 @@ static int dlfilter__close(struct dlfilter *d)
return dlclose(d->handle);
}

-struct dlfilter *dlfilter__new(const char *file)
+struct dlfilter *dlfilter__new(const char *file, int dlargc, char **dlargv)
{
struct dlfilter *d = malloc(sizeof(*d));

if (!d)
return NULL;

- if (dlfilter__init(d, file))
+ if (dlfilter__init(d, file, dlargc, dlargv))
goto err_free;

if (dlfilter__open(d))
@@ -253,16 +272,28 @@ int dlfilter__start(struct dlfilter *d, struct perf_session *session)
{
if (d) {
d->session = session;
- if (d->start)
- return d->start(&d->data, d);
+ if (d->start) {
+ int ret;
+
+ d->in_start = true;
+ ret = d->start(&d->data, d);
+ d->in_start = false;
+ return ret;
+ }
}
return 0;
}

static int dlfilter__stop(struct dlfilter *d)
{
- if (d && d->stop)
- return d->stop(d->data, d);
+ if (d && d->stop) {
+ int ret;
+
+ d->in_stop = true;
+ ret = d->stop(d->data, d);
+ d->in_stop = false;
+ return ret;
+ }
return 0;
}

diff --git a/tools/perf/util/dlfilter.h b/tools/perf/util/dlfilter.h
index a1ed38da3ce6..505980442360 100644
--- a/tools/perf/util/dlfilter.h
+++ b/tools/perf/util/dlfilter.h
@@ -23,6 +23,10 @@ struct dlfilter {
void *data;
struct perf_session *session;
bool ctx_valid;
+ bool in_start;
+ bool in_stop;
+ int dlargc;
+ char **dlargv;

union perf_event *event;
struct perf_sample *sample;
@@ -47,7 +51,7 @@ struct dlfilter {
struct perf_dlfilter_fns *fns;
};

-struct dlfilter *dlfilter__new(const char *file);
+struct dlfilter *dlfilter__new(const char *file, int dlargc, char **dlargv);

int dlfilter__start(struct dlfilter *d, struct perf_session *session);

diff --git a/tools/perf/util/perf_dlfilter.h b/tools/perf/util/perf_dlfilter.h
index 31ad4c100181..35e03aa41a7f 100644
--- a/tools/perf/util/perf_dlfilter.h
+++ b/tools/perf/util/perf_dlfilter.h
@@ -90,8 +90,10 @@ struct perf_dlfilter_fns {
const struct perf_dlfilter_al *(*resolve_ip)(void *ctx);
/* Return information about addr (if addr_correlates_sym) */
const struct perf_dlfilter_al *(*resolve_addr)(void *ctx);
+ /* Return arguments from --dlarg option */
+ char **(*args)(void *ctx, int *dlargc);
/* Reserved */
- void *(*reserved[126])(void *);
+ void *(*reserved[125])(void *);
};

/*
--
2.17.1