Commit ebcb9464 authored Mar 02, 2020 by Arnaldo Carvalho de Melo

perf env: Do not return pointers to local variables



It is possible to return a pointer to a local variable when looking up
the architecture name for the running system and no normalization is
done on that value, i.e. we may end up returning the uts.machine local
variable.

While this doesn't happen on most arches, as normalization takes place,
lets fix this by making that a static variable and optimize it a bit by
not always running uname(), only the first time.

Noticed in fedora rawhide running with:

  [perfbuilder@a5ff49d6e6e4 ~]$ gcc --version
  gcc (GCC) 10.0.1 20200216 (Red Hat 10.0.1-0.8)

Reported-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent cff20b31

tools/perf/util/env.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -343,11 +343,11 @@ static const char normalize_arch(char arch)

		const char perf_env__arch(struct perf_env env)
		{
		struct utsname uts;
		char *arch_name;

		if (!env \|\| !env->arch) { /* Assume local operation */
		if (uname(&uts) < 0)
		static struct utsname uts = { .machine[0] = '\0', };
		if (uts.machine[0] == '\0' && uname(&uts) < 0)
		return NULL;
		arch_name = uts.machine;
		} else

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