[tip:perf/core] perf utils: Readlink /proc/self/exe to find the perf binary

From: tip-bot for Tommi Rantala
Date: Tue Mar 28 2017 - 02:03:57 EST


Commit-ID: 55f77128e7652e537d6c226d5b56821cdb5c22de
Gitweb: http://git.kernel.org/tip/55f77128e7652e537d6c226d5b56821cdb5c22de
Author: Tommi Rantala <tommi.t.rantala@xxxxxxxxx>
AuthorDate: Wed, 22 Mar 2017 15:06:24 +0200
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Mon, 27 Mar 2017 15:37:54 -0300

perf utils: Readlink /proc/self/exe to find the perf binary

Simplification: it is easier to open /proc/self/exe than /proc/$pid/exe.

Signed-off-by: Tommi Rantala <tommi.t.rantala@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20170322130624.21881-7-tommi.t.rantala@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/header.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index cf22962..ef09f26 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -370,15 +370,11 @@ static int write_cmdline(int fd, struct perf_header *h __maybe_unused,
struct perf_evlist *evlist __maybe_unused)
{
char buf[MAXPATHLEN];
- char proc[32];
u32 n;
int i, ret;

- /*
- * actual atual path to perf binary
- */
- sprintf(proc, "/proc/%d/exe", getpid());
- ret = readlink(proc, buf, sizeof(buf) - 1);
+ /* actual path to perf binary */
+ ret = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
if (ret <= 0)
return -1;