[PATCH v3 0/5] perf-probe: Improve probing on versioned symbols

[PATCH v3 0/5] perf-probe: Improve probing on versioned symbols

[Masami Hiramatsu]

Hi,

Here is the 3rd version of the series for probing on
versioned symbols in libraries. This includes 5 patches
to fix the issues discussed on perf-users ML 
(https://www.spinics.net/lists/linux-perf-users/msg04637.html)

The first version (and detail note) is here;
 https://lkml.org/lkml/2017/12/5/1124

Here is the updates;

[1/5] Update error message. Arnaldo, I dropped the latter 
  half from error message because it doesn't try to write
  the name to the kprobe_events interface.
[4/5] Fix 2 bugs (Thanks Thomas-Mich Richter!)
[5/5] Update according to previous patch.

Thank you,
---

Masami Hiramatsu (5):
      perf-probe: Add warning message if there is unexpected event name
      perf-probe: Cut off the version suffix from event name
      perf-probe: Add __return suffix for return events
      perf-probe: Find versioned symbols from map
      perf-probe: Support escaped character in parser


 tools/perf/Documentation/perf-probe.txt     |   18 +++++-
 tools/perf/arch/powerpc/util/sym-handling.c |    8 +++
 tools/perf/util/probe-event.c               |   84 +++++++++++++++++++--------
 tools/perf/util/string.c                    |   46 +++++++++++++++
 tools/perf/util/string2.h                   |    2 +
 tools/perf/util/symbol.c                    |    5 ++
 tools/perf/util/symbol.h                    |    1 
 7 files changed, 139 insertions(+), 25 deletions(-)

--
Masami Hiramatsu (Linaro Ltd.) <mhiramat@kernel.org>

[PATCH v3 1/5] perf-probe: Add warning message if there is unexpected event name

[Masami Hiramatsu]

This improve the error message so that user can know
event-name error before writing new events to
kprobe-events interface.

E.g.
   ======
   #./perf probe -x /lib64/libc-2.25.so malloc_get_state*
   Internal error: "malloc_get_state@GLIBC_2" is an invalid event name.
     Error: Failed to add events.
   ======

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
---
 Changes in v3:
  - Update the error message.
---
 tools/perf/util/probe-event.c |    8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index b7aaf9b2294d..262d5da86623 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2625,6 +2625,14 @@ static int get_new_event_name(char *buf, size_t len, const char *base,
 
 out:
 	free(nbase);
+
+	/* Final validation */
+	if (ret >= 0 && !is_c_func_name(buf)) {
+		pr_warning("Internal error: \"%s\" is an invalid event name.\n",
+			   buf);
+		ret = -EINVAL;
+	}
+
 	return ret;
 }
 

[tip:perf/core] perf probe: Add warning message if there is unexpected event name

[tip-bot for Masami Hiramatsu]

Commit-ID:  9f5c6d8777a2d962b0eeacb2a16f37da6bea545b
Gitweb:     https://git.kernel.org/tip/9f5c6d8777a2d962b0eeacb2a16f37da6bea545b
Author:     Masami Hiramatsu <mhiramat@kernel.org>
AuthorDate: Sat, 9 Dec 2017 01:26:46 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Wed, 27 Dec 2017 12:15:53 -0300

perf probe: Add warning message if there is unexpected event name

This improve the error message so that user can know event-name error
before writing new events to kprobe-events interface.

E.g.
   ======
   #./perf probe -x /lib64/libc-2.25.so malloc_get_state*
   Internal error: "malloc_get_state@GLIBC_2" is an invalid event name.
     Error: Failed to add events.
   ======

Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Reviewed-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: bhargavb <bhargavaramudu@gmail.com>
Cc: linux-rt-users@vger.kernel.org
Link: http://lkml.kernel.org/r/151275040665.24652.5188568529237584489.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/probe-event.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index b7aaf9b..262d5da 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2625,6 +2625,14 @@ static int get_new_event_name(char *buf, size_t len, const char *base,
 
 out:
 	free(nbase);
+
+	/* Final validation */
+	if (ret >= 0 && !is_c_func_name(buf)) {
+		pr_warning("Internal error: \"%s\" is an invalid event name.\n",
+			   buf);
+		ret = -EINVAL;
+	}
+
 	return ret;
 }
 

[PATCH v3 2/5] perf-probe: Cut off the version suffix from event name

[Masami Hiramatsu]

Cut off the version suffix (e.g. @GLIBC_2.2.5 etc.) from
automatic generated event name. This fixes wildcard event
adding like below case;

  =====
  # perf probe -x /lib64/libc-2.25.so malloc*
  Internal error: "malloc_get_state@GLIBC_2" is wrong event name.
    Error: Failed to add events.
  =====

This failure was caused by a versioned suffix symbol.
With this fix, perf probe automatically cuts the
suffix after @ as below.

  =====
  # ./perf probe -x /lib64/libc-2.25.so malloc*
  Added new events:
    probe_libc:malloc_printerr (on malloc* in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_consolidate (on malloc* in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_check (on malloc* in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_hook_ini (on malloc* in /usr/lib64/libc-2.25.so)
    probe_libc:malloc    (on malloc* in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_trim (on malloc* in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_usable_size (on malloc* in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_stats (on malloc* in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_info (on malloc* in /usr/lib64/libc-2.25.so)
    probe_libc:mallochook (on malloc* in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_get_state (on malloc* in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_set_state (on malloc* in /usr/lib64/libc-2.25.so)

  You can now use it in all perf tools, such as:

	  perf record -e probe_libc:malloc_set_state -aR sleep 1

  =====

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Reported-by: bhargavb <bhargavaramudu@gmail.com>
Acked-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
---
 tools/perf/util/probe-event.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 262d5da86623..7e582547ac07 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2584,8 +2584,8 @@ static int get_new_event_name(char *buf, size_t len, const char *base,
 	if (!nbase)
 		return -ENOMEM;
 
-	/* Cut off the dot suffixes (e.g. .const, .isra)*/
-	p = strchr(nbase, '.');
+	/* Cut off the dot suffixes (e.g. .const, .isra) and version suffixes */
+	p = strpbrk(nbase, ".@");
 	if (p && p != nbase)
 		*p = '\0';
 

[PATCH v3 3/5] perf-probe: Add __return suffix for return events

[Masami Hiramatsu]

Add __return suffix for function return events
automatically. Without this, user have to give --force
option and will see the number suffix for each event
like "function_1", which is not easy to recognize.
Instead, this adds __return suffix to it automatically.
E.g.

  =====
  # ./perf probe -x /lib64/libc-2.25.so 'malloc*%return'
  Added new events:
    probe_libc:malloc_printerr__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_consolidate__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_check__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_hook_ini__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_trim__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_usable_size__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_stats__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_info__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:mallochook__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_get_state__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_set_state__return (on malloc*%return in /usr/lib64/libc-2.25.so)

  You can now use it in all perf tools, such as:

	  perf record -e probe_libc:malloc_set_state__return -aR sleep 1

  =====

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Acked-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
---
  Changes in v2:
   - Add a description in Documentation/perf-probe.txt.
---
 tools/perf/Documentation/perf-probe.txt |    2 +-
 tools/perf/util/probe-event.c           |    9 +++++----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
index d7e4869905f1..f96382692f42 100644
--- a/tools/perf/Documentation/perf-probe.txt
+++ b/tools/perf/Documentation/perf-probe.txt
@@ -170,7 +170,7 @@ Probe points are defined by following syntax.
      or,
      sdt_PROVIDER:SDTEVENT
 
-'EVENT' specifies the name of new event, if omitted, it will be set the name of the probed function. You can also specify a group name by 'GROUP', if omitted, set 'probe' is used for kprobe and 'probe_<bin>' is used for uprobe.
+'EVENT' specifies the name of new event, if omitted, it will be set the name of the probed function, and for return probes, a "\_\_return" suffix is automatically added to the function name. You can also specify a group name by 'GROUP', if omitted, set 'probe' is used for kprobe and 'probe_<bin>' is used for uprobe.
 Note that using existing group name can conflict with other events. Especially, using the group name reserved for kernel modules can hide embedded events in the
 modules.
 'FUNC' specifies a probed function name, and it may have one of the following options; '+OFFS' is the offset from function entry address in bytes, ':RLN' is the relative-line number from function entry line, and '%return' means that it probes function return. And ';PTN' means lazy matching pattern (see LAZY MATCHING). Note that ';PTN' must be the end of the probe point definition.  In addition, '@SRC' specifies a source file which has that function.
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 7e582547ac07..a68141d360b0 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2573,7 +2573,8 @@ int show_perf_probe_events(struct strfilter *filter)
 }
 
 static int get_new_event_name(char *buf, size_t len, const char *base,
-			      struct strlist *namelist, bool allow_suffix)
+			      struct strlist *namelist, bool ret_event,
+			      bool allow_suffix)
 {
 	int i, ret;
 	char *p, *nbase;
@@ -2590,7 +2591,7 @@ static int get_new_event_name(char *buf, size_t len, const char *base,
 		*p = '\0';
 
 	/* Try no suffix number */
-	ret = e_snprintf(buf, len, "%s", nbase);
+	ret = e_snprintf(buf, len, "%s%s", nbase, ret_event ? "__return" : "");
 	if (ret < 0) {
 		pr_debug("snprintf() failed: %d\n", ret);
 		goto out;
@@ -2689,8 +2690,8 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev,
 		group = PERFPROBE_GROUP;
 
 	/* Get an unused new event name */
-	ret = get_new_event_name(buf, 64, event,
-				 namelist, allow_suffix);
+	ret = get_new_event_name(buf, 64, event, namelist,
+				 tev->point.retprobe, allow_suffix);
 	if (ret < 0)
 		return ret;
 

[tip:perf/core] perf probe: Add __return suffix for return events

[tip-bot for Masami Hiramatsu]

Commit-ID:  e63c625a1e417edbe513b75b347a7238e9e7fea0
Gitweb:     https://git.kernel.org/tip/e63c625a1e417edbe513b75b347a7238e9e7fea0
Author:     Masami Hiramatsu <mhiramat@kernel.org>
AuthorDate: Sat, 9 Dec 2017 01:27:44 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Wed, 27 Dec 2017 12:15:54 -0300

perf probe: Add __return suffix for return events

Add __return suffix for function return events automatically. Without
this, user have to give --force option and will see the number suffix
for each event like "function_1", which is not easy to recognize.
Instead, this adds __return suffix to it automatically.  E.g.

  =====
  # ./perf probe -x /lib64/libc-2.25.so 'malloc*%return'
  Added new events:
    probe_libc:malloc_printerr__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_consolidate__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_check__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_hook_ini__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_trim__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_usable_size__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_stats__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_info__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:mallochook__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_get_state__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_set_state__return (on malloc*%return in /usr/lib64/libc-2.25.so)

  You can now use it in all perf tools, such as:

	  perf record -e probe_libc:malloc_set_state__return -aR sleep 1

  =====

Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Reviewed-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: bhargavb <bhargavaramudu@gmail.com>
Cc: linux-rt-users@vger.kernel.org
Link: http://lkml.kernel.org/r/151275046418.24652.6696011972866498489.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/Documentation/perf-probe.txt | 2 +-
 tools/perf/util/probe-event.c           | 9 +++++----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
index d7e4869..f963826 100644
--- a/tools/perf/Documentation/perf-probe.txt
+++ b/tools/perf/Documentation/perf-probe.txt
@@ -170,7 +170,7 @@ Probe points are defined by following syntax.
      or,
      sdt_PROVIDER:SDTEVENT
 
-'EVENT' specifies the name of new event, if omitted, it will be set the name of the probed function. You can also specify a group name by 'GROUP', if omitted, set 'probe' is used for kprobe and 'probe_<bin>' is used for uprobe.
+'EVENT' specifies the name of new event, if omitted, it will be set the name of the probed function, and for return probes, a "\_\_return" suffix is automatically added to the function name. You can also specify a group name by 'GROUP', if omitted, set 'probe' is used for kprobe and 'probe_<bin>' is used for uprobe.
 Note that using existing group name can conflict with other events. Especially, using the group name reserved for kernel modules can hide embedded events in the
 modules.
 'FUNC' specifies a probed function name, and it may have one of the following options; '+OFFS' is the offset from function entry address in bytes, ':RLN' is the relative-line number from function entry line, and '%return' means that it probes function return. And ';PTN' means lazy matching pattern (see LAZY MATCHING). Note that ';PTN' must be the end of the probe point definition.  In addition, '@SRC' specifies a source file which has that function.
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 7e58254..a68141d 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2573,7 +2573,8 @@ int show_perf_probe_events(struct strfilter *filter)
 }
 
 static int get_new_event_name(char *buf, size_t len, const char *base,
-			      struct strlist *namelist, bool allow_suffix)
+			      struct strlist *namelist, bool ret_event,
+			      bool allow_suffix)
 {
 	int i, ret;
 	char *p, *nbase;
@@ -2590,7 +2591,7 @@ static int get_new_event_name(char *buf, size_t len, const char *base,
 		*p = '\0';
 
 	/* Try no suffix number */
-	ret = e_snprintf(buf, len, "%s", nbase);
+	ret = e_snprintf(buf, len, "%s%s", nbase, ret_event ? "__return" : "");
 	if (ret < 0) {
 		pr_debug("snprintf() failed: %d\n", ret);
 		goto out;
@@ -2689,8 +2690,8 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev,
 		group = PERFPROBE_GROUP;
 
 	/* Get an unused new event name */
-	ret = get_new_event_name(buf, 64, event,
-				 namelist, allow_suffix);
+	ret = get_new_event_name(buf, 64, event, namelist,
+				 tev->point.retprobe, allow_suffix);
 	if (ret < 0)
 		return ret;
 

[PATCH v3 4/5] perf-probe: Find versioned symbols from map

[Masami Hiramatsu]

Find versioned symbols correctly from map.
Commit d80406453ad4 ("perf symbols: Allow user probes on
versioned symbols") allows user to find default versioned
symbols (with "@@") in map. However, it did not enable
normal versioned symbol (with "@") for perf-probe.
E.g.

  =====
  # ./perf probe -x /lib64/libc-2.25.so malloc_get_state
  Failed to find symbol malloc_get_state in /usr/lib64/libc-2.25.so
    Error: Failed to add events.
  =====

This solves above issue by improving perf-probe symbol
search function, as below.

  =====
  # ./perf probe -x /lib64/libc-2.25.so malloc_get_state
  Added new event:
    probe_libc:malloc_get_state (on malloc_get_state in /usr/lib64/libc-2.25.so)

  You can now use it in all perf tools, such as:

	  perf record -e probe_libc:malloc_get_state -aR sleep 1

  # ./perf probe -l
    probe_libc:malloc_get_state (on malloc_get_state@GLIBC_2.2.5 in /usr/lib64/libc-2.25.so)
  =====

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Acked-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
---
  Changes in v3:
   - Fix to return -ENOMEM if strndup fails.
   - Fix to check name != NULL before refering it in
     arch__normalize_symbol_name() for ppc.
---
 tools/perf/arch/powerpc/util/sym-handling.c |    8 ++++++++
 tools/perf/util/probe-event.c               |   20 ++++++++++++++++++--
 tools/perf/util/symbol.c                    |    5 +++++
 tools/perf/util/symbol.h                    |    1 +
 4 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/tools/perf/arch/powerpc/util/sym-handling.c b/tools/perf/arch/powerpc/util/sym-handling.c
index 9c4e23d8c8ce..53d83d7e6a09 100644
--- a/tools/perf/arch/powerpc/util/sym-handling.c
+++ b/tools/perf/arch/powerpc/util/sym-handling.c
@@ -64,6 +64,14 @@ int arch__compare_symbol_names_n(const char *namea, const char *nameb,
 
 	return strncmp(namea, nameb, n);
 }
+
+const char *arch__normalize_symbol_name(const char *name)
+{
+	/* Skip over initial dot */
+	if (name && *name == '.')
+		name++;
+	return name;
+}
 #endif
 
 #if defined(_CALL_ELF) && _CALL_ELF == 2
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index a68141d360b0..0d6c66d51939 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2801,16 +2801,32 @@ static int find_probe_functions(struct map *map, char *name,
 	int found = 0;
 	struct symbol *sym;
 	struct rb_node *tmp;
+	const char *norm, *ver;
+	char *buf = NULL;
 
 	if (map__load(map) < 0)
 		return 0;
 
 	map__for_each_symbol(map, sym, tmp) {
-		if (strglobmatch(sym->name, name)) {
+		norm = arch__normalize_symbol_name(sym->name);
+		if (!norm)
+			continue;
+
+		/* We don't care about default symbol or not */
+		ver = strchr(norm, '@');
+		if (ver) {
+			buf = strndup(norm, ver - norm);
+			if (!buf)
+				return -ENOMEM;
+			norm = buf;
+		}
+		if (strglobmatch(norm, name)) {
 			found++;
 			if (syms && found < probe_conf.max_probes)
 				syms[found - 1] = sym;
 		}
+		if (buf)
+			zfree(&buf);
 	}
 
 	return found;
@@ -2856,7 +2872,7 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
 	 * same name but different addresses, this lists all the symbols.
 	 */
 	num_matched_functions = find_probe_functions(map, pp->function, syms);
-	if (num_matched_functions == 0) {
+	if (num_matched_functions <= 0) {
 		pr_err("Failed to find symbol %s in %s\n", pp->function,
 			pev->target ? : "kernel");
 		ret = -ENOENT;
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 1b67a8639dfe..cc065d4bfafc 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -94,6 +94,11 @@ static int prefix_underscores_count(const char *str)
 	return tail - str;
 }
 
+const char * __weak arch__normalize_symbol_name(const char *name)
+{
+	return name;
+}
+
 int __weak arch__compare_symbol_names(const char *namea, const char *nameb)
 {
 	return strcmp(namea, nameb);
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index a4f0075b4e5c..0563f33c1eb3 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -349,6 +349,7 @@ bool elf__needs_adjust_symbols(GElf_Ehdr ehdr);
 void arch__sym_update(struct symbol *s, GElf_Sym *sym);
 #endif
 
+const char *arch__normalize_symbol_name(const char *name);
 #define SYMBOL_A 0
 #define SYMBOL_B 1
 

[tip:perf/core] perf probe: Find versioned symbols from map

[tip-bot for Masami Hiramatsu]

Commit-ID:  4b3a2716dd785fabb9f6ac80c1d53cb29a88169d
Gitweb:     https://git.kernel.org/tip/4b3a2716dd785fabb9f6ac80c1d53cb29a88169d
Author:     Masami Hiramatsu <mhiramat@kernel.org>
AuthorDate: Sat, 9 Dec 2017 01:28:12 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Wed, 27 Dec 2017 12:15:54 -0300

perf probe: Find versioned symbols from map

Commit d80406453ad4 ("perf symbols: Allow user probes on versioned
symbols") allows user to find default versioned symbols (with "@@") in
map. However, it did not enable normal versioned symbol (with "@") for
perf-probe.  E.g.

  =====
  # ./perf probe -x /lib64/libc-2.25.so malloc_get_state
  Failed to find symbol malloc_get_state in /usr/lib64/libc-2.25.so
    Error: Failed to add events.
  =====

This solves above issue by improving perf-probe symbol search function,
as below.

  =====
  # ./perf probe -x /lib64/libc-2.25.so malloc_get_state
  Added new event:
    probe_libc:malloc_get_state (on malloc_get_state in /usr/lib64/libc-2.25.so)

  You can now use it in all perf tools, such as:

	  perf record -e probe_libc:malloc_get_state -aR sleep 1

  # ./perf probe -l
    probe_libc:malloc_get_state (on malloc_get_state@GLIBC_2.2.5 in /usr/lib64/libc-2.25.so)
  =====

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Acked-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: bhargavb <bhargavaramudu@gmail.com>
Cc: linux-rt-users@vger.kernel.org
Link: http://lkml.kernel.org/r/151275049269.24652.1639103455496216255.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/arch/powerpc/util/sym-handling.c |  8 ++++++++
 tools/perf/util/probe-event.c               | 20 ++++++++++++++++++--
 tools/perf/util/symbol.c                    |  5 +++++
 tools/perf/util/symbol.h                    |  1 +
 4 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/tools/perf/arch/powerpc/util/sym-handling.c b/tools/perf/arch/powerpc/util/sym-handling.c
index 9c4e23d..53d83d7 100644
--- a/tools/perf/arch/powerpc/util/sym-handling.c
+++ b/tools/perf/arch/powerpc/util/sym-handling.c
@@ -64,6 +64,14 @@ int arch__compare_symbol_names_n(const char *namea, const char *nameb,
 
 	return strncmp(namea, nameb, n);
 }
+
+const char *arch__normalize_symbol_name(const char *name)
+{
+	/* Skip over initial dot */
+	if (name && *name == '.')
+		name++;
+	return name;
+}
 #endif
 
 #if defined(_CALL_ELF) && _CALL_ELF == 2
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index a68141d..0d6c66d 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2801,16 +2801,32 @@ static int find_probe_functions(struct map *map, char *name,
 	int found = 0;
 	struct symbol *sym;
 	struct rb_node *tmp;
+	const char *norm, *ver;
+	char *buf = NULL;
 
 	if (map__load(map) < 0)
 		return 0;
 
 	map__for_each_symbol(map, sym, tmp) {
-		if (strglobmatch(sym->name, name)) {
+		norm = arch__normalize_symbol_name(sym->name);
+		if (!norm)
+			continue;
+
+		/* We don't care about default symbol or not */
+		ver = strchr(norm, '@');
+		if (ver) {
+			buf = strndup(norm, ver - norm);
+			if (!buf)
+				return -ENOMEM;
+			norm = buf;
+		}
+		if (strglobmatch(norm, name)) {
 			found++;
 			if (syms && found < probe_conf.max_probes)
 				syms[found - 1] = sym;
 		}
+		if (buf)
+			zfree(&buf);
 	}
 
 	return found;
@@ -2856,7 +2872,7 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
 	 * same name but different addresses, this lists all the symbols.
 	 */
 	num_matched_functions = find_probe_functions(map, pp->function, syms);
-	if (num_matched_functions == 0) {
+	if (num_matched_functions <= 0) {
 		pr_err("Failed to find symbol %s in %s\n", pp->function,
 			pev->target ? : "kernel");
 		ret = -ENOENT;
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 1b67a86..cc065d4 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -94,6 +94,11 @@ static int prefix_underscores_count(const char *str)
 	return tail - str;
 }
 
+const char * __weak arch__normalize_symbol_name(const char *name)
+{
+	return name;
+}
+
 int __weak arch__compare_symbol_names(const char *namea, const char *nameb)
 {
 	return strcmp(namea, nameb);
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index a4f0075..0563f33 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -349,6 +349,7 @@ bool elf__needs_adjust_symbols(GElf_Ehdr ehdr);
 void arch__sym_update(struct symbol *s, GElf_Sym *sym);
 #endif
 
+const char *arch__normalize_symbol_name(const char *name);
 #define SYMBOL_A 0
 #define SYMBOL_B 1
 

[PATCH v3 5/5] perf-probe: Support escaped character in parser

[Masami Hiramatsu]

Support the special characters escaped by '\' in parser.
This allows user to specify versions directly like below.

  =====
  # ./perf probe -x /lib64/libc-2.25.so malloc_get_state\\@GLIBC_2.2.5
  Added new event:
    probe_libc:malloc_get_state (on malloc_get_state@GLIBC_2.2.5 in /usr/lib64/libc-2.25.so)

  You can now use it in all perf tools, such as:

	  perf record -e probe_libc:malloc_get_state -aR sleep 1

  =====

Or, you can use separators in source filename, e.g.

  =====
  # ./perf probe -x /opt/test/a.out foo+bar.c:3
  Semantic error :There is non-digit character in offset.
    Error: Command Parse Error.
  =====

Usually "+" in source file cause parser error, but

  =====
  # ./perf probe -x /opt/test/a.out foo\\+bar.c:4
  Added new event:
    probe_a:main         (on @foo+bar.c:4 in /opt/test/a.out)

  You can now use it in all perf tools, such as:

	  perf record -e probe_a:main -aR sleep 1
  =====

escaped "\+" allows you to specify that.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Acked-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
---
 Changes in v2:
  - Add a description and samples in Documentation/perf-probe.txt
 Changes in v3:
  - Update for new series.
---
 tools/perf/Documentation/perf-probe.txt |   16 +++++++++
 tools/perf/util/probe-event.c           |   57 ++++++++++++++++++-------------
 tools/perf/util/string.c                |   46 +++++++++++++++++++++++++
 tools/perf/util/string2.h               |    2 +
 4 files changed, 98 insertions(+), 23 deletions(-)

diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
index f96382692f42..b6866a05edd2 100644
--- a/tools/perf/Documentation/perf-probe.txt
+++ b/tools/perf/Documentation/perf-probe.txt
@@ -182,6 +182,14 @@ Note that before using the SDT event, the target binary (on which SDT events are
 For details of the SDT, see below.
 https://sourceware.org/gdb/onlinedocs/gdb/Static-Probe-Points.html
 
+ESCAPED CHARACTER
+-----------------
+
+In the probe syntax, '=', '@', '+', ':' and ';' are treated as a special character. You can use a backslash ('\') to escape the special characters.
+This is useful if you need to probe on a specific versioned symbols, like @GLIBC_... suffixes, or also you need to specify a source file which includes the special characters.
+Note that usually single backslash is consumed by shell, so you might need to pass double backslash (\\) or wrapping with single quotes (\'AAA\@BBB').
+See EXAMPLES how it is used.
+
 PROBE ARGUMENT
 --------------
 Each probe argument follows below syntax.
@@ -277,6 +285,14 @@ Add a USDT probe to a target process running in a different mount namespace
 
  ./perf probe --target-ns <target pid> -x /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.121-0.b13.el7_3.x86_64/jre/lib/amd64/server/libjvm.so %sdt_hotspot:thread__sleep__end
 
+Add a probe on specific versioned symbol by backslash escape
+
+ ./perf probe -x /lib64/libc-2.25.so 'malloc_get_state\@GLIBC_2.2.5'
+
+Add a probe in a source file using special characters by backslash escape
+
+ ./perf probe -x /opt/test/a.out 'foo\+bar.c:4'
+
 
 SEE ALSO
 --------
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 0d6c66d51939..735972e7bc6b 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -1325,27 +1325,30 @@ static int parse_perf_probe_event_name(char **arg, struct perf_probe_event *pev)
 {
 	char *ptr;
 
-	ptr = strchr(*arg, ':');
+	ptr = strpbrk_esc(*arg, ":");
 	if (ptr) {
 		*ptr = '\0';
 		if (!pev->sdt && !is_c_func_name(*arg))
 			goto ng_name;
-		pev->group = strdup(*arg);
+		pev->group = strdup_esc(*arg);
 		if (!pev->group)
 			return -ENOMEM;
 		*arg = ptr + 1;
 	} else
 		pev->group = NULL;
-	if (!pev->sdt && !is_c_func_name(*arg)) {
+
+	pev->event = strdup_esc(*arg);
+	if (pev->event == NULL)
+		return -ENOMEM;
+
+	if (!pev->sdt && !is_c_func_name(pev->event)) {
+		zfree(&pev->event);
 ng_name:
+		zfree(&pev->group);
 		semantic_error("%s is bad for event name -it must "
 			       "follow C symbol-naming rule.\n", *arg);
 		return -EINVAL;
 	}
-	pev->event = strdup(*arg);
-	if (pev->event == NULL)
-		return -ENOMEM;
-
 	return 0;
 }
 
@@ -1373,7 +1376,7 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
 			arg++;
 	}
 
-	ptr = strpbrk(arg, ";=@+%");
+	ptr = strpbrk_esc(arg, ";=@+%");
 	if (pev->sdt) {
 		if (ptr) {
 			if (*ptr != '@') {
@@ -1387,7 +1390,7 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
 				pev->target = build_id_cache__origname(tmp);
 				free(tmp);
 			} else
-				pev->target = strdup(ptr + 1);
+				pev->target = strdup_esc(ptr + 1);
 			if (!pev->target)
 				return -ENOMEM;
 			*ptr = '\0';
@@ -1421,13 +1424,14 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
 	 *
 	 * Otherwise, we consider arg to be a function specification.
 	 */
-	if (!strpbrk(arg, "+@%") && (ptr = strpbrk(arg, ";:")) != NULL) {
+	if (!strpbrk_esc(arg, "+@%")) {
+		ptr = strpbrk_esc(arg, ";:");
 		/* This is a file spec if it includes a '.' before ; or : */
-		if (memchr(arg, '.', ptr - arg))
+		if (ptr && memchr(arg, '.', ptr - arg))
 			file_spec = true;
 	}
 
-	ptr = strpbrk(arg, ";:+@%");
+	ptr = strpbrk_esc(arg, ";:+@%");
 	if (ptr) {
 		nc = *ptr;
 		*ptr++ = '\0';
@@ -1436,7 +1440,7 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
 	if (arg[0] == '\0')
 		tmp = NULL;
 	else {
-		tmp = strdup(arg);
+		tmp = strdup_esc(arg);
 		if (tmp == NULL)
 			return -ENOMEM;
 	}
@@ -1469,12 +1473,12 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
 		arg = ptr;
 		c = nc;
 		if (c == ';') {	/* Lazy pattern must be the last part */
-			pp->lazy_line = strdup(arg);
+			pp->lazy_line = strdup(arg); /* let leave escapes */
 			if (pp->lazy_line == NULL)
 				return -ENOMEM;
 			break;
 		}
-		ptr = strpbrk(arg, ";:+@%");
+		ptr = strpbrk_esc(arg, ";:+@%");
 		if (ptr) {
 			nc = *ptr;
 			*ptr++ = '\0';
@@ -1501,7 +1505,7 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
 				semantic_error("SRC@SRC is not allowed.\n");
 				return -EINVAL;
 			}
-			pp->file = strdup(arg);
+			pp->file = strdup_esc(arg);
 			if (pp->file == NULL)
 				return -ENOMEM;
 			break;
@@ -2803,23 +2807,30 @@ static int find_probe_functions(struct map *map, char *name,
 	struct rb_node *tmp;
 	const char *norm, *ver;
 	char *buf = NULL;
+	bool cut_version = true;
 
 	if (map__load(map) < 0)
 		return 0;
 
+	/* If user gives a version, don't cut off the version from symbols */
+	if (strchr(name, '@'))
+		cut_version = false;
+
 	map__for_each_symbol(map, sym, tmp) {
 		norm = arch__normalize_symbol_name(sym->name);
 		if (!norm)
 			continue;
 
-		/* We don't care about default symbol or not */
-		ver = strchr(norm, '@');
-		if (ver) {
-			buf = strndup(norm, ver - norm);
-			if (!buf)
-				return -ENOMEM;
-			norm = buf;
+		if (cut_version) {
+			/* We don't care about default symbol or not */
+			ver = strchr(norm, '@');
+			if (ver) {
+				buf = strndup(norm, ver - norm);
+				if (!buf)
+					return -ENOMEM;
+				norm = buf;
 		}
+
 		if (strglobmatch(norm, name)) {
 			found++;
 			if (syms && found < probe_conf.max_probes)
diff --git a/tools/perf/util/string.c b/tools/perf/util/string.c
index aaa08ee8c717..d8bfd0c4d2cb 100644
--- a/tools/perf/util/string.c
+++ b/tools/perf/util/string.c
@@ -396,3 +396,49 @@ char *asprintf_expr_inout_ints(const char *var, bool in, size_t nints, int *ints
 	free(expr);
 	return NULL;
 }
+
+/* Like strpbrk(), but not break if it is right after a backslash (escaped) */
+char *strpbrk_esc(char *str, const char *stopset)
+{
+	char *ptr;
+
+	do {
+		ptr = strpbrk(str, stopset);
+		if (ptr == str ||
+		    (ptr == str + 1 && *(ptr - 1) != '\\'))
+			break;
+		str = ptr + 1;
+	} while (ptr && *(ptr - 1) == '\\' && *(ptr - 2) != '\\');
+
+	return ptr;
+}
+
+/* Like strdup, but do not copy a single backslash */
+char *strdup_esc(const char *str)
+{
+	char *s, *d, *p, *ret = strdup(str);
+
+	if (!ret)
+		return NULL;
+
+	d = strchr(ret, '\\');
+	if (!d)
+		return ret;
+
+	s = d + 1;
+	do {
+		if (*s == '\0') {
+			*d = '\0';
+			break;
+		}
+		p = strchr(s + 1, '\\');
+		if (p) {
+			memmove(d, s, p - s);
+			d += p - s;
+			s = p + 1;
+		} else
+			memmove(d, s, strlen(s) + 1);
+	} while (p);
+
+	return ret;
+}
diff --git a/tools/perf/util/string2.h b/tools/perf/util/string2.h
index ee14ca5451ab..4c68a09b97e8 100644
--- a/tools/perf/util/string2.h
+++ b/tools/perf/util/string2.h
@@ -39,5 +39,7 @@ static inline char *asprintf_expr_not_in_ints(const char *var, size_t nints, int
 	return asprintf_expr_inout_ints(var, false, nints, ints);
 }
 
+char *strpbrk_esc(char *str, const char *stopset);
+char *strdup_esc(const char *str);
 
 #endif /* PERF_STRING_H */

Re: [PATCH v3 5/5] perf-probe: Support escaped character in parser

[Arnaldo Carvalho de Melo]

Em Sat, Dec 09, 2017 at 01:28:41AM +0900, Masami Hiramatsu escreveu:
> Support the special characters escaped by '\' in parser.
> This allows user to specify versions directly like below.
> 
>   =====
>   # ./perf probe -x /lib64/libc-2.25.so malloc_get_state\\@GLIBC_2.2.5
>   Added new event:
>     probe_libc:malloc_get_state (on malloc_get_state@GLIBC_2.2.5 in /usr/lib64/libc-2.25.so)
> 
>   You can now use it in all perf tools, such as:
> 
> 	  perf record -e probe_libc:malloc_get_state -aR sleep 1
> 
>   =====
> 
> Or, you can use separators in source filename, e.g.
> 
>   =====
>   # ./perf probe -x /opt/test/a.out foo+bar.c:3
>   Semantic error :There is non-digit character in offset.
>     Error: Command Parse Error.
>   =====
> 
> Usually "+" in source file cause parser error, but
> 
>   =====
>   # ./perf probe -x /opt/test/a.out foo\\+bar.c:4
>   Added new event:
>     probe_a:main         (on @foo+bar.c:4 in /opt/test/a.out)
> 
>   You can now use it in all perf tools, such as:
> 
> 	  perf record -e probe_a:main -aR sleep 1
>   =====
> 
> escaped "\+" allows you to specify that.
> 
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> Reviewed-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
> Acked-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
> ---
>  Changes in v2:
>   - Add a description and samples in Documentation/perf-probe.txt
>  Changes in v3:
>   - Update for new series.
> ---
>  tools/perf/Documentation/perf-probe.txt |   16 +++++++++
>  tools/perf/util/probe-event.c           |   57 ++++++++++++++++++-------------
>  tools/perf/util/string.c                |   46 +++++++++++++++++++++++++
>  tools/perf/util/string2.h               |    2 +
>  4 files changed, 98 insertions(+), 23 deletions(-)
> 
> diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
> index f96382692f42..b6866a05edd2 100644
> --- a/tools/perf/Documentation/perf-probe.txt
> +++ b/tools/perf/Documentation/perf-probe.txt
> @@ -182,6 +182,14 @@ Note that before using the SDT event, the target binary (on which SDT events are
>  For details of the SDT, see below.
>  https://sourceware.org/gdb/onlinedocs/gdb/Static-Probe-Points.html
>  
> +ESCAPED CHARACTER
> +-----------------
> +
> +In the probe syntax, '=', '@', '+', ':' and ';' are treated as a special character. You can use a backslash ('\') to escape the special characters.
> +This is useful if you need to probe on a specific versioned symbols, like @GLIBC_... suffixes, or also you need to specify a source file which includes the special characters.
> +Note that usually single backslash is consumed by shell, so you might need to pass double backslash (\\) or wrapping with single quotes (\'AAA\@BBB').
> +See EXAMPLES how it is used.
> +
>  PROBE ARGUMENT
>  --------------
>  Each probe argument follows below syntax.
> @@ -277,6 +285,14 @@ Add a USDT probe to a target process running in a different mount namespace
>  
>   ./perf probe --target-ns <target pid> -x /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.121-0.b13.el7_3.x86_64/jre/lib/amd64/server/libjvm.so %sdt_hotspot:thread__sleep__end
>  
> +Add a probe on specific versioned symbol by backslash escape
> +
> + ./perf probe -x /lib64/libc-2.25.so 'malloc_get_state\@GLIBC_2.2.5'
> +
> +Add a probe in a source file using special characters by backslash escape
> +
> + ./perf probe -x /opt/test/a.out 'foo\+bar.c:4'
> +
>  
>  SEE ALSO
>  --------
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index 0d6c66d51939..735972e7bc6b 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -1325,27 +1325,30 @@ static int parse_perf_probe_event_name(char **arg, struct perf_probe_event *pev)
>  {
>  	char *ptr;
>  
> -	ptr = strchr(*arg, ':');
> +	ptr = strpbrk_esc(*arg, ":");
>  	if (ptr) {
>  		*ptr = '\0';
>  		if (!pev->sdt && !is_c_func_name(*arg))
>  			goto ng_name;
> -		pev->group = strdup(*arg);
> +		pev->group = strdup_esc(*arg);
>  		if (!pev->group)
>  			return -ENOMEM;
>  		*arg = ptr + 1;
>  	} else
>  		pev->group = NULL;
> -	if (!pev->sdt && !is_c_func_name(*arg)) {
> +
> +	pev->event = strdup_esc(*arg);
> +	if (pev->event == NULL)
> +		return -ENOMEM;
> +
> +	if (!pev->sdt && !is_c_func_name(pev->event)) {
> +		zfree(&pev->event);
>  ng_name:
> +		zfree(&pev->group);
>  		semantic_error("%s is bad for event name -it must "
>  			       "follow C symbol-naming rule.\n", *arg);
>  		return -EINVAL;
>  	}
> -	pev->event = strdup(*arg);
> -	if (pev->event == NULL)
> -		return -ENOMEM;
> -
>  	return 0;
>  }
>  
> @@ -1373,7 +1376,7 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
>  			arg++;
>  	}
>  
> -	ptr = strpbrk(arg, ";=@+%");
> +	ptr = strpbrk_esc(arg, ";=@+%");
>  	if (pev->sdt) {
>  		if (ptr) {
>  			if (*ptr != '@') {
> @@ -1387,7 +1390,7 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
>  				pev->target = build_id_cache__origname(tmp);
>  				free(tmp);
>  			} else
> -				pev->target = strdup(ptr + 1);
> +				pev->target = strdup_esc(ptr + 1);
>  			if (!pev->target)
>  				return -ENOMEM;
>  			*ptr = '\0';
> @@ -1421,13 +1424,14 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
>  	 *
>  	 * Otherwise, we consider arg to be a function specification.
>  	 */
> -	if (!strpbrk(arg, "+@%") && (ptr = strpbrk(arg, ";:")) != NULL) {
> +	if (!strpbrk_esc(arg, "+@%")) {
> +		ptr = strpbrk_esc(arg, ";:");
>  		/* This is a file spec if it includes a '.' before ; or : */
> -		if (memchr(arg, '.', ptr - arg))
> +		if (ptr && memchr(arg, '.', ptr - arg))
>  			file_spec = true;
>  	}
>  
> -	ptr = strpbrk(arg, ";:+@%");
> +	ptr = strpbrk_esc(arg, ";:+@%");
>  	if (ptr) {
>  		nc = *ptr;
>  		*ptr++ = '\0';
> @@ -1436,7 +1440,7 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
>  	if (arg[0] == '\0')
>  		tmp = NULL;
>  	else {
> -		tmp = strdup(arg);
> +		tmp = strdup_esc(arg);
>  		if (tmp == NULL)
>  			return -ENOMEM;
>  	}
> @@ -1469,12 +1473,12 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
>  		arg = ptr;
>  		c = nc;
>  		if (c == ';') {	/* Lazy pattern must be the last part */
> -			pp->lazy_line = strdup(arg);
> +			pp->lazy_line = strdup(arg); /* let leave escapes */
>  			if (pp->lazy_line == NULL)
>  				return -ENOMEM;
>  			break;
>  		}
> -		ptr = strpbrk(arg, ";:+@%");
> +		ptr = strpbrk_esc(arg, ";:+@%");
>  		if (ptr) {
>  			nc = *ptr;
>  			*ptr++ = '\0';
> @@ -1501,7 +1505,7 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
>  				semantic_error("SRC@SRC is not allowed.\n");
>  				return -EINVAL;
>  			}
> -			pp->file = strdup(arg);
> +			pp->file = strdup_esc(arg);
>  			if (pp->file == NULL)
>  				return -ENOMEM;
>  			break;
> @@ -2803,23 +2807,30 @@ static int find_probe_functions(struct map *map, char *name,
>  	struct rb_node *tmp;
>  	const char *norm, *ver;
>  	char *buf = NULL;
> +	bool cut_version = true;
>  
>  	if (map__load(map) < 0)
>  		return 0;
>  
> +	/* If user gives a version, don't cut off the version from symbols */
> +	if (strchr(name, '@'))
> +		cut_version = false;
> +
>  	map__for_each_symbol(map, sym, tmp) {
>  		norm = arch__normalize_symbol_name(sym->name);
>  		if (!norm)
>  			continue;
>  
> -		/* We don't care about default symbol or not */
> -		ver = strchr(norm, '@');
> -		if (ver) {
> -			buf = strndup(norm, ver - norm);
> -			if (!buf)
> -				return -ENOMEM;
> -			norm = buf;
> +		if (cut_version) {
> +			/* We don't care about default symbol or not */
> +			ver = strchr(norm, '@');
> +			if (ver) {
> +				buf = strndup(norm, ver - norm);
> +				if (!buf)
> +					return -ENOMEM;
> +				norm = buf;

You forgot a } here, please check this logic and resubmit just this last
patch, without the string.c and string2.h part, that I already split
from this one and applied.

gcc diagnostics:

  LD       /tmp/build/perf/perf-in.o
util/probe-event.c: In function ‘find_probe_functions’:
util/probe-event.c:2848:17: error: declaration of ‘map’ shadows a parameter [-Werror=shadow]
     struct map *map __maybe_unused,
                 ^~~
util/probe-event.c:2802:45: note: shadowed declaration is here
 static int find_probe_functions(struct map *map, char *name,
                                             ^~~
util/probe-event.c:2849:20: error: declaration of ‘sym’ shadows a previous local [-Werror=shadow]
     struct symbol *sym __maybe_unused) { }

------------------------

clang's:

  CC       /tmp/build/perf/util/probe-event.o
util/probe-event.c:2849:40: error: function definition is not allowed here
                                struct symbol *sym __maybe_unused) { }
                                                                   ^
util/probe-event.c:2857:1: error: function definition is not allowed here
{
^
util/probe-event.c:3009:1: error: function definition is not allowed here
{
^
util/probe-event.c:3098:1: error: function definition is not allowed here
{
^
util/probe-event.c:3112:1: error: function definition is not allowed here

------------------------

Neither are that informative... ;-\

- Arnaldo

>  		}
> +
>  		if (strglobmatch(norm, name)) {
>  			found++;
>  			if (syms && found < probe_conf.max_probes)
> diff --git a/tools/perf/util/string.c b/tools/perf/util/string.c
> index aaa08ee8c717..d8bfd0c4d2cb 100644
> --- a/tools/perf/util/string.c
> +++ b/tools/perf/util/string.c
> @@ -396,3 +396,49 @@ char *asprintf_expr_inout_ints(const char *var, bool in, size_t nints, int *ints
>  	free(expr);
>  	return NULL;
>  }
> +
> +/* Like strpbrk(), but not break if it is right after a backslash (escaped) */
> +char *strpbrk_esc(char *str, const char *stopset)
> +{
> +	char *ptr;
> +
> +	do {
> +		ptr = strpbrk(str, stopset);
> +		if (ptr == str ||
> +		    (ptr == str + 1 && *(ptr - 1) != '\\'))
> +			break;
> +		str = ptr + 1;
> +	} while (ptr && *(ptr - 1) == '\\' && *(ptr - 2) != '\\');
> +
> +	return ptr;
> +}
> +
> +/* Like strdup, but do not copy a single backslash */
> +char *strdup_esc(const char *str)
> +{
> +	char *s, *d, *p, *ret = strdup(str);
> +
> +	if (!ret)
> +		return NULL;
> +
> +	d = strchr(ret, '\\');
> +	if (!d)
> +		return ret;
> +
> +	s = d + 1;
> +	do {
> +		if (*s == '\0') {
> +			*d = '\0';
> +			break;
> +		}
> +		p = strchr(s + 1, '\\');
> +		if (p) {
> +			memmove(d, s, p - s);
> +			d += p - s;
> +			s = p + 1;
> +		} else
> +			memmove(d, s, strlen(s) + 1);
> +	} while (p);
> +
> +	return ret;
> +}
> diff --git a/tools/perf/util/string2.h b/tools/perf/util/string2.h
> index ee14ca5451ab..4c68a09b97e8 100644
> --- a/tools/perf/util/string2.h
> +++ b/tools/perf/util/string2.h
> @@ -39,5 +39,7 @@ static inline char *asprintf_expr_not_in_ints(const char *var, size_t nints, int
>  	return asprintf_expr_inout_ints(var, false, nints, ints);
>  }
>  
> +char *strpbrk_esc(char *str, const char *stopset);
> +char *strdup_esc(const char *str);
>  
>  #endif /* PERF_STRING_H */

Re: [PATCH v3 5/5] perf-probe: Support escaped character in parser

[Masami Hiramatsu]

On Mon, 11 Dec 2017 17:03:30 -0300
Arnaldo Carvalho de Melo <acme@kernel.org> wrote:

> Em Sat, Dec 09, 2017 at 01:28:41AM +0900, Masami Hiramatsu escreveu:
> > Support the special characters escaped by '\' in parser.
> > This allows user to specify versions directly like below.
> > 
> >   =====
> >   # ./perf probe -x /lib64/libc-2.25.so malloc_get_state\\@GLIBC_2.2.5
> >   Added new event:
> >     probe_libc:malloc_get_state (on malloc_get_state@GLIBC_2.2.5 in /usr/lib64/libc-2.25.so)
> > 
> >   You can now use it in all perf tools, such as:
> > 
> > 	  perf record -e probe_libc:malloc_get_state -aR sleep 1
> > 
> >   =====
> > 
> > Or, you can use separators in source filename, e.g.
> > 
> >   =====
> >   # ./perf probe -x /opt/test/a.out foo+bar.c:3
> >   Semantic error :There is non-digit character in offset.
> >     Error: Command Parse Error.
> >   =====
> > 
> > Usually "+" in source file cause parser error, but
> > 
> >   =====
> >   # ./perf probe -x /opt/test/a.out foo\\+bar.c:4
> >   Added new event:
> >     probe_a:main         (on @foo+bar.c:4 in /opt/test/a.out)
> > 
> >   You can now use it in all perf tools, such as:
> > 
> > 	  perf record -e probe_a:main -aR sleep 1
> >   =====
> > 
> > escaped "\+" allows you to specify that.
> > 
> > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> > Reviewed-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
> > Acked-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
> > ---
> >  Changes in v2:
> >   - Add a description and samples in Documentation/perf-probe.txt
> >  Changes in v3:
> >   - Update for new series.
> > ---
> >  tools/perf/Documentation/perf-probe.txt |   16 +++++++++
> >  tools/perf/util/probe-event.c           |   57 ++++++++++++++++++-------------
> >  tools/perf/util/string.c                |   46 +++++++++++++++++++++++++
> >  tools/perf/util/string2.h               |    2 +
> >  4 files changed, 98 insertions(+), 23 deletions(-)
> > 
> > diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
> > index f96382692f42..b6866a05edd2 100644
> > --- a/tools/perf/Documentation/perf-probe.txt
> > +++ b/tools/perf/Documentation/perf-probe.txt
> > @@ -182,6 +182,14 @@ Note that before using the SDT event, the target binary (on which SDT events are
> >  For details of the SDT, see below.
> >  https://sourceware.org/gdb/onlinedocs/gdb/Static-Probe-Points.html
> >  
> > +ESCAPED CHARACTER
> > +-----------------
> > +
> > +In the probe syntax, '=', '@', '+', ':' and ';' are treated as a special character. You can use a backslash ('\') to escape the special characters.
> > +This is useful if you need to probe on a specific versioned symbols, like @GLIBC_... suffixes, or also you need to specify a source file which includes the special characters.
> > +Note that usually single backslash is consumed by shell, so you might need to pass double backslash (\\) or wrapping with single quotes (\'AAA\@BBB').
> > +See EXAMPLES how it is used.
> > +
> >  PROBE ARGUMENT
> >  --------------
> >  Each probe argument follows below syntax.
> > @@ -277,6 +285,14 @@ Add a USDT probe to a target process running in a different mount namespace
> >  
> >   ./perf probe --target-ns <target pid> -x /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.121-0.b13.el7_3.x86_64/jre/lib/amd64/server/libjvm.so %sdt_hotspot:thread__sleep__end
> >  
> > +Add a probe on specific versioned symbol by backslash escape
> > +
> > + ./perf probe -x /lib64/libc-2.25.so 'malloc_get_state\@GLIBC_2.2.5'
> > +
> > +Add a probe in a source file using special characters by backslash escape
> > +
> > + ./perf probe -x /opt/test/a.out 'foo\+bar.c:4'
> > +
> >  
> >  SEE ALSO
> >  --------
> > diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> > index 0d6c66d51939..735972e7bc6b 100644
> > --- a/tools/perf/util/probe-event.c
> > +++ b/tools/perf/util/probe-event.c
> > @@ -1325,27 +1325,30 @@ static int parse_perf_probe_event_name(char **arg, struct perf_probe_event *pev)
> >  {
> >  	char *ptr;
> >  
> > -	ptr = strchr(*arg, ':');
> > +	ptr = strpbrk_esc(*arg, ":");
> >  	if (ptr) {
> >  		*ptr = '\0';
> >  		if (!pev->sdt && !is_c_func_name(*arg))
> >  			goto ng_name;
> > -		pev->group = strdup(*arg);
> > +		pev->group = strdup_esc(*arg);
> >  		if (!pev->group)
> >  			return -ENOMEM;
> >  		*arg = ptr + 1;
> >  	} else
> >  		pev->group = NULL;
> > -	if (!pev->sdt && !is_c_func_name(*arg)) {
> > +
> > +	pev->event = strdup_esc(*arg);
> > +	if (pev->event == NULL)
> > +		return -ENOMEM;
> > +
> > +	if (!pev->sdt && !is_c_func_name(pev->event)) {
> > +		zfree(&pev->event);
> >  ng_name:
> > +		zfree(&pev->group);
> >  		semantic_error("%s is bad for event name -it must "
> >  			       "follow C symbol-naming rule.\n", *arg);
> >  		return -EINVAL;
> >  	}
> > -	pev->event = strdup(*arg);
> > -	if (pev->event == NULL)
> > -		return -ENOMEM;
> > -
> >  	return 0;
> >  }
> >  
> > @@ -1373,7 +1376,7 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
> >  			arg++;
> >  	}
> >  
> > -	ptr = strpbrk(arg, ";=@+%");
> > +	ptr = strpbrk_esc(arg, ";=@+%");
> >  	if (pev->sdt) {
> >  		if (ptr) {
> >  			if (*ptr != '@') {
> > @@ -1387,7 +1390,7 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
> >  				pev->target = build_id_cache__origname(tmp);
> >  				free(tmp);
> >  			} else
> > -				pev->target = strdup(ptr + 1);
> > +				pev->target = strdup_esc(ptr + 1);
> >  			if (!pev->target)
> >  				return -ENOMEM;
> >  			*ptr = '\0';
> > @@ -1421,13 +1424,14 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
> >  	 *
> >  	 * Otherwise, we consider arg to be a function specification.
> >  	 */
> > -	if (!strpbrk(arg, "+@%") && (ptr = strpbrk(arg, ";:")) != NULL) {
> > +	if (!strpbrk_esc(arg, "+@%")) {
> > +		ptr = strpbrk_esc(arg, ";:");
> >  		/* This is a file spec if it includes a '.' before ; or : */
> > -		if (memchr(arg, '.', ptr - arg))
> > +		if (ptr && memchr(arg, '.', ptr - arg))
> >  			file_spec = true;
> >  	}
> >  
> > -	ptr = strpbrk(arg, ";:+@%");
> > +	ptr = strpbrk_esc(arg, ";:+@%");
> >  	if (ptr) {
> >  		nc = *ptr;
> >  		*ptr++ = '\0';
> > @@ -1436,7 +1440,7 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
> >  	if (arg[0] == '\0')
> >  		tmp = NULL;
> >  	else {
> > -		tmp = strdup(arg);
> > +		tmp = strdup_esc(arg);
> >  		if (tmp == NULL)
> >  			return -ENOMEM;
> >  	}
> > @@ -1469,12 +1473,12 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
> >  		arg = ptr;
> >  		c = nc;
> >  		if (c == ';') {	/* Lazy pattern must be the last part */
> > -			pp->lazy_line = strdup(arg);
> > +			pp->lazy_line = strdup(arg); /* let leave escapes */
> >  			if (pp->lazy_line == NULL)
> >  				return -ENOMEM;
> >  			break;
> >  		}
> > -		ptr = strpbrk(arg, ";:+@%");
> > +		ptr = strpbrk_esc(arg, ";:+@%");
> >  		if (ptr) {
> >  			nc = *ptr;
> >  			*ptr++ = '\0';
> > @@ -1501,7 +1505,7 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
> >  				semantic_error("SRC@SRC is not allowed.\n");
> >  				return -EINVAL;
> >  			}
> > -			pp->file = strdup(arg);
> > +			pp->file = strdup_esc(arg);
> >  			if (pp->file == NULL)
> >  				return -ENOMEM;
> >  			break;
> > @@ -2803,23 +2807,30 @@ static int find_probe_functions(struct map *map, char *name,
> >  	struct rb_node *tmp;
> >  	const char *norm, *ver;
> >  	char *buf = NULL;
> > +	bool cut_version = true;
> >  
> >  	if (map__load(map) < 0)
> >  		return 0;
> >  
> > +	/* If user gives a version, don't cut off the version from symbols */
> > +	if (strchr(name, '@'))
> > +		cut_version = false;
> > +
> >  	map__for_each_symbol(map, sym, tmp) {
> >  		norm = arch__normalize_symbol_name(sym->name);
> >  		if (!norm)
> >  			continue;
> >  
> > -		/* We don't care about default symbol or not */
> > -		ver = strchr(norm, '@');
> > -		if (ver) {
> > -			buf = strndup(norm, ver - norm);
> > -			if (!buf)
> > -				return -ENOMEM;
> > -			norm = buf;
> > +		if (cut_version) {
> > +			/* We don't care about default symbol or not */
> > +			ver = strchr(norm, '@');
> > +			if (ver) {
> > +				buf = strndup(norm, ver - norm);
> > +				if (!buf)
> > +					return -ENOMEM;
> > +				norm = buf;
> 
> You forgot a } here, please check this logic and resubmit just this last
> patch, without the string.c and string2.h part, that I already split
> from this one and applied.

OOPS! thanks! I missed something around that.... maybe while updating patches.
Hmm, I might be so upset...

OK, anyway, I'll do that. 

> 
> gcc diagnostics:
> 
>   LD       /tmp/build/perf/perf-in.o
> util/probe-event.c: In function ‘find_probe_functions’:
> util/probe-event.c:2848:17: error: declaration of ‘map’ shadows a parameter [-Werror=shadow]
>      struct map *map __maybe_unused,
>                  ^~~
> util/probe-event.c:2802:45: note: shadowed declaration is here
>  static int find_probe_functions(struct map *map, char *name,
>                                              ^~~
> util/probe-event.c:2849:20: error: declaration of ‘sym’ shadows a previous local [-Werror=shadow]
>      struct symbol *sym __maybe_unused) { }
> 
> ------------------------
> 
> clang's:
> 
>   CC       /tmp/build/perf/util/probe-event.o
> util/probe-event.c:2849:40: error: function definition is not allowed here
>                                 struct symbol *sym __maybe_unused) { }
>                                                                    ^
> util/probe-event.c:2857:1: error: function definition is not allowed here
> {
> ^
> util/probe-event.c:3009:1: error: function definition is not allowed here
> {
> ^
> util/probe-event.c:3098:1: error: function definition is not allowed here
> {
> ^
> util/probe-event.c:3112:1: error: function definition is not allowed here
> 
> ------------------------
> 
> Neither are that informative... ;-\

Sorry, that's my mistake...

Thank you,

> 
> - Arnaldo
> 
> >  		}
> > +
> >  		if (strglobmatch(norm, name)) {
> >  			found++;
> >  			if (syms && found < probe_conf.max_probes)
> > diff --git a/tools/perf/util/string.c b/tools/perf/util/string.c
> > index aaa08ee8c717..d8bfd0c4d2cb 100644
> > --- a/tools/perf/util/string.c
> > +++ b/tools/perf/util/string.c
> > @@ -396,3 +396,49 @@ char *asprintf_expr_inout_ints(const char *var, bool in, size_t nints, int *ints
> >  	free(expr);
> >  	return NULL;
> >  }
> > +
> > +/* Like strpbrk(), but not break if it is right after a backslash (escaped) */
> > +char *strpbrk_esc(char *str, const char *stopset)
> > +{
> > +	char *ptr;
> > +
> > +	do {
> > +		ptr = strpbrk(str, stopset);
> > +		if (ptr == str ||
> > +		    (ptr == str + 1 && *(ptr - 1) != '\\'))
> > +			break;
> > +		str = ptr + 1;
> > +	} while (ptr && *(ptr - 1) == '\\' && *(ptr - 2) != '\\');
> > +
> > +	return ptr;
> > +}
> > +
> > +/* Like strdup, but do not copy a single backslash */
> > +char *strdup_esc(const char *str)
> > +{
> > +	char *s, *d, *p, *ret = strdup(str);
> > +
> > +	if (!ret)
> > +		return NULL;
> > +
> > +	d = strchr(ret, '\\');
> > +	if (!d)
> > +		return ret;
> > +
> > +	s = d + 1;
> > +	do {
> > +		if (*s == '\0') {
> > +			*d = '\0';
> > +			break;
> > +		}
> > +		p = strchr(s + 1, '\\');
> > +		if (p) {
> > +			memmove(d, s, p - s);
> > +			d += p - s;
> > +			s = p + 1;
> > +		} else
> > +			memmove(d, s, strlen(s) + 1);
> > +	} while (p);
> > +
> > +	return ret;
> > +}
> > diff --git a/tools/perf/util/string2.h b/tools/perf/util/string2.h
> > index ee14ca5451ab..4c68a09b97e8 100644
> > --- a/tools/perf/util/string2.h
> > +++ b/tools/perf/util/string2.h
> > @@ -39,5 +39,7 @@ static inline char *asprintf_expr_not_in_ints(const char *var, size_t nints, int
> >  	return asprintf_expr_inout_ints(var, false, nints, ints);
> >  }
> >  
> > +char *strpbrk_esc(char *str, const char *stopset);
> > +char *strdup_esc(const char *str);
> >  
> >  #endif /* PERF_STRING_H */


-- 
Masami Hiramatsu <mhiramat@kernel.org>

Re: [PATCH v3 5/5] perf-probe: Support escaped character in parser

[Arnaldo Carvalho de Melo]

Em Tue, Dec 12, 2017 at 11:46:00PM +0900, Masami Hiramatsu escreveu:
> On Mon, 11 Dec 2017 17:03:30 -0300
> Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
> > > -		/* We don't care about default symbol or not */
> > > -		ver = strchr(norm, '@');
> > > -		if (ver) {
> > > -			buf = strndup(norm, ver - norm);
> > > -			if (!buf)
> > > -				return -ENOMEM;
> > > -			norm = buf;
> > > +		if (cut_version) {
> > > +			/* We don't care about default symbol or not */
> > > +			ver = strchr(norm, '@');
> > > +			if (ver) {
> > > +				buf = strndup(norm, ver - norm);
> > > +				if (!buf)
> > > +					return -ENOMEM;
> > > +				norm = buf;

> > You forgot a } here, please check this logic and resubmit just this last
> > patch, without the string.c and string2.h part, that I already split
> > from this one and applied.
 
> OOPS! thanks! I missed something around that.... maybe while updating patches.
> Hmm, I might be so upset...
 
> OK, anyway, I'll do that. 

Nah, happens sometimes, one last round of building before submitting
would catch that tho... 8-) :-)

- Arnaldo

[tip:perf/core] perf string: Add {strdup,strpbrk}_esc()

[tip-bot for Masami Hiramatsu]

Commit-ID:  1e9f9e8af0de80e8f6a47d991df66090934be0c6
Gitweb:     https://git.kernel.org/tip/1e9f9e8af0de80e8f6a47d991df66090934be0c6
Author:     Masami Hiramatsu <mhiramat@kernel.org>
AuthorDate: Sat, 9 Dec 2017 01:28:41 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Wed, 27 Dec 2017 12:15:55 -0300

perf string: Add {strdup,strpbrk}_esc()

To support the special characters escaped by '\' in 'perf probe' event parser.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Acked-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: bhargavb <bhargavaramudu@gmail.com>
Cc: linux-rt-users@vger.kernel.org
Link: http://lkml.kernel.org/r/151275052163.24652.18205979384585484358.stgit@devbox
[ Split from a larger patch ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/string.c  | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/string2.h |  2 ++
 2 files changed, 48 insertions(+)

diff --git a/tools/perf/util/string.c b/tools/perf/util/string.c
index aaa08ee..d8bfd0c 100644
--- a/tools/perf/util/string.c
+++ b/tools/perf/util/string.c
@@ -396,3 +396,49 @@ out_err_overflow:
 	free(expr);
 	return NULL;
 }
+
+/* Like strpbrk(), but not break if it is right after a backslash (escaped) */
+char *strpbrk_esc(char *str, const char *stopset)
+{
+	char *ptr;
+
+	do {
+		ptr = strpbrk(str, stopset);
+		if (ptr == str ||
+		    (ptr == str + 1 && *(ptr - 1) != '\\'))
+			break;
+		str = ptr + 1;
+	} while (ptr && *(ptr - 1) == '\\' && *(ptr - 2) != '\\');
+
+	return ptr;
+}
+
+/* Like strdup, but do not copy a single backslash */
+char *strdup_esc(const char *str)
+{
+	char *s, *d, *p, *ret = strdup(str);
+
+	if (!ret)
+		return NULL;
+
+	d = strchr(ret, '\\');
+	if (!d)
+		return ret;
+
+	s = d + 1;
+	do {
+		if (*s == '\0') {
+			*d = '\0';
+			break;
+		}
+		p = strchr(s + 1, '\\');
+		if (p) {
+			memmove(d, s, p - s);
+			d += p - s;
+			s = p + 1;
+		} else
+			memmove(d, s, strlen(s) + 1);
+	} while (p);
+
+	return ret;
+}
diff --git a/tools/perf/util/string2.h b/tools/perf/util/string2.h
index ee14ca5..4c68a09 100644
--- a/tools/perf/util/string2.h
+++ b/tools/perf/util/string2.h
@@ -39,5 +39,7 @@ static inline char *asprintf_expr_not_in_ints(const char *var, size_t nints, int
 	return asprintf_expr_inout_ints(var, false, nints, ints);
 }
 
+char *strpbrk_esc(char *str, const char *stopset);
+char *strdup_esc(const char *str);
 
 #endif /* PERF_STRING_H */