perf probe: List probes in stdout

Since commit 5e17b28f1e24 ("perf probe: Add --quiet option to
suppress output result message") have replaced printf with pr_info,
perf probe -l outputs its result in stderr. However, that is not
what the commit expected.

E.g.:

  # perf probe -l > /dev/null
    probe:vfs_read       (on vfs_read@ksrc/linux-3/fs/read_write.c)

With this fix:

  # perf probe -l > list
  # cat list
    probe:vfs_read       (on vfs_read@ksrc/linux-3/fs/read_write.c)

Of course, --quiet(-q) still works on --add/--del.

  # perf probe -q vfs_write
  # perf probe -l
    probe:vfs_read       (on vfs_read@ksrc/linux-3/fs/read_write.c)
    probe:vfs_write      (on vfs_write@ksrc/linux-3/fs/read_write.c)
  -----

Reported-by: Naohiro Aota <naota@elisp.net>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naohiro Aota <naota@elisp.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20150613013116.24402.2923.stgit@localhost.localdomain
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index daa24a249e05a9015addc6ee0e6f990167b92449..c4ab58870fcc9f72e5de4b21021a550932f19724 100644 (file)
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2126,9 +2126,9 @@ kprobe_blacklist__find_by_address(struct list_head *blacklist,
        return NULL;
 }
 
-/* Show an event */
-static int show_perf_probe_event(struct perf_probe_event *pev,
-                                const char *module)
+static int perf_probe_event__sprintf(struct perf_probe_event *pev,
+                                    const char *module,
+                                    struct strbuf *result)
 {
        int i, ret;
        char buf[128];
@@ -2141,27 +2141,47 @@ static int show_perf_probe_event(struct perf_probe_event *pev,
 
        ret = e_snprintf(buf, 128, "%s:%s", pev->group, pev->event);
        if (ret < 0)
-               return ret;
+               goto out;
 
-       pr_info("  %-20s (on %s", buf, place);
+       strbuf_addf(result, "  %-20s (on %s", buf, place);
        if (module)
-               pr_info(" in %s", module);
+               strbuf_addf(result, " in %s", module);
 
        if (pev->nargs > 0) {
-               pr_info(" with");
+               strbuf_addstr(result, " with");
                for (i = 0; i < pev->nargs; i++) {
                        ret = synthesize_perf_probe_arg(&pev->args[i],
                                                        buf, 128);
                        if (ret < 0)
-                               break;
-                       pr_info(" %s", buf);
+                               goto out;
+                       strbuf_addf(result, " %s", buf);
                }
        }
-       pr_info(")\n");
+       strbuf_addch(result, ')');
+out:
        free(place);
        return ret;
 }
 
+/* Show an event */
+static int show_perf_probe_event(struct perf_probe_event *pev,
+                                const char *module, bool use_stdout)
+{
+       struct strbuf buf = STRBUF_INIT;
+       int ret;
+
+       ret = perf_probe_event__sprintf(pev, module, &buf);
+       if (ret >= 0) {
+               if (use_stdout)
+                       printf("%s\n", buf.buf);
+               else
+                       pr_info("%s\n", buf.buf);
+       }
+       strbuf_release(&buf);
+
+       return ret;
+}
+
 static bool filter_probe_trace_event(struct probe_trace_event *tev,
                                     struct strfilter *filter)
 {
@@ -2200,9 +2220,10 @@ static int __show_perf_probe_events(int fd, bool is_kprobe,
                                goto next;
                        ret = convert_to_perf_probe_event(&tev, &pev,
                                                                is_kprobe);
-                       if (ret >= 0)
-                               ret = show_perf_probe_event(&pev,
-                                                           tev.point.module);
+                       if (ret < 0)
+                               goto next;
+                       ret = show_perf_probe_event(&pev, tev.point.module,
+                                                   true);
                }
 next:
                clear_perf_probe_event(&pev);
@@ -2468,7 +2489,7 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
                group = pev->group;
                pev->event = tev->event;
                pev->group = tev->group;
-               show_perf_probe_event(pev, tev->point.module);
+               show_perf_probe_event(pev, tev->point.module, false);
                /* Trick here - restore current event/group */
                pev->event = (char *)event;
                pev->group = (char *)group;