[PATCH perf/core v3 1/3] [BUGFIX] perf probe: List probes in stdout

Masami Hiramatsu
2015-06-16T11:55:04Z

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)
-----

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reported-by: Naohiro Aota <naota@elisp.net>

---
Changes in v2:
- Fix to reverse the use_stdio flag at each caller.
---
tools/perf/util/probe-event.c | 49 +++++++++++++++++++++++++++++------------
1 file changed, 35 insertions(+), 14 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index daa24a2..c4ab588 100644
--- 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;