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: 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/151309111236.18107.5634753157435343410.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
index f963826..b6866a0 100644 (file)
--- 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 0d6c66d..e1dbc98 100644 (file)
--- 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 +2807,31 @@ 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)