Re: [PATCH 08/11] perf tools: Add perf_exe() helper to find perf binary

[Jiri Olsa <jolsa@redhat.com>]

On Sun, Feb 24, 2019 at 07:37:19AM -0800, Andi Kleen wrote:
> From: Andi Kleen <ak@linux.intel.com>
> 
> Also convert one existing user.
> 
> Signed-off-by: Andi Kleen <ak@linux.intel.com>

Acked-by: Jiri Olsa <jolsa@kernel.org>

thanks,
jirka

> ---
>  tools/perf/util/header.c | 12 +++---------
>  tools/perf/util/util.c   | 10 ++++++++++
>  tools/perf/util/util.h   |  2 ++
>  3 files changed, 15 insertions(+), 9 deletions(-)
> 
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index 61ce197c5362..2f290a0343d4 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -526,17 +526,11 @@ static int write_event_desc(struct feat_fd *ff,
>  static int write_cmdline(struct feat_fd *ff,
>  			 struct perf_evlist *evlist __maybe_unused)
>  {
> -	char buf[MAXPATHLEN];
> -	u32 n;
> -	int i, ret;
> +	char pbuf[MAXPATHLEN], *buf;
> +	int i, ret, n;
>  
>  	/* actual path to perf binary */
> -	ret = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
> -	if (ret <= 0)
> -		return -1;
> -
> -	/* readlink() does not add null termination */
> -	buf[ret] = '\0';
> +	buf = perf_exe(pbuf, MAXPATHLEN);
>  
>  	/* account for binary path */
>  	n = perf_env.nr_cmdline + 1;
> diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
> index 320b0fef249a..dd693e018aef 100644
> --- a/tools/perf/util/util.c
> +++ b/tools/perf/util/util.c
> @@ -507,3 +507,13 @@ const char *perf_tip(const char *dirpath)
>  
>  	return tip;
>  }
> +
> +char *perf_exe(char *buf, int len)
> +{
> +	int n = readlink("/proc/self/exe", buf, len);
> +	if (n > 0) {
> +		buf[n] = 0;
> +		return buf;
> +	}
> +	return strcpy(buf, "perf");
> +}
> diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
> index ece040b799f6..dc2a99ad5c96 100644
> --- a/tools/perf/util/util.h
> +++ b/tools/perf/util/util.h
> @@ -76,6 +76,8 @@ extern bool perf_singlethreaded;
>  void perf_set_singlethreaded(void);
>  void perf_set_multithreaded(void);
>  
> +char *perf_exe(char *buf, int len);
> +
>  #ifndef O_CLOEXEC
>  #ifdef __sparc__
>  #define O_CLOEXEC      0x400000
> -- 
> 2.17.2
>