Commit c588d158 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Arnaldo Carvalho de Melo
Browse files

perf probe: Support escaped character in parser 



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: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: default avatarThomas Richter <tmricht@linux.vnet.ibm.com>
Acked-by: default avatarRavi 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/151309111236.18107.5634753157435343410.stgit@devbox


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 1e9f9e8a

tools/perf/Documentation/perf-probe.txt

+16 −0
Original line number Diff line number Diff line
@@ -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

--------

tools/perf/util/probe-event.c

+35 −23
Original line number Diff line number Diff line
@@ -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;
@@ -2803,15 +2807,21 @@ 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;



		if (cut_version) {

			/* We don't care about default symbol or not */

			ver = strchr(norm, '@');

			if (ver) {
@@ -2820,6 +2830,8 @@ static int find_probe_functions(struct map *map, char *name, 
					return -ENOMEM;

				norm = buf;

			}

		}



		if (strglobmatch(norm, name)) {

			found++;

			if (syms && found < probe_conf.max_probes)

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