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perf tools: use XSI-complaint version of strerror_r() instead of GNU-specific

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Perf uses GNU-specific version of strerror_r(). The GNU-specific strerror_r()
returns a pointer to a string containing the error message.  This may be either
a pointer to a string that the function stores in buf, or a pointer to some
(immutable) static string (in which case buf is unused).

In glibc-2.16 GNU version was marked with attribute warn_unused_result.  It
triggers few warnings in perf:

util/target.c: In function ‘perf_target__strerror’:
util/target.c:114:13: error: ignoring return value of ‘strerror_r’, declared with attribute warn_unused_result [-Werror=unused-result]
ui/browsers/hists.c: In function ‘hist_browser__dump’:
ui/browsers/hists.c:981:13: error: ignoring return value of ‘strerror_r’, declared with attribute warn_unused_result [-Werror=unused-result]

They are bugs.

Let's fix strerror_r() usage.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Acked-by: Ulrich Drepper <drepper@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ulrich Drepper <drepper@gmail.com>
Link: http://lkml.kernel.org/r/20120723210654.GA25248@shutemov.name
[ committer note: s/assert/BUG_ON/g ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Kirill A. Shutemov 2012-07-24 00:06:54 +03:00 committed by Arnaldo Carvalho de Melo
parent 4a841d650e
commit 4cc49d4dc8
2 changed files with 12 additions and 3 deletions
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4
tools/perf/ui/browsers/hists.c
View File

@ -978,8 +978,8 @@ static int hist_browser__dump(struct hist_browser *browser)
fp = fopen(filename, "w"); fp = fopen(filename, "w");
if (fp == NULL) { if (fp == NULL) {
char bf[64]; char bf[64];
strerror_r(errno, bf, sizeof(bf)); const char *err = strerror_r(errno, bf, sizeof(bf));
ui_helpline__fpush("Couldn't write to %s: %s", filename, bf); ui_helpline__fpush("Couldn't write to %s: %s", filename, err);
return -1; return -1;
} }

11
tools/perf/util/target.c
View File

@ -110,8 +110,17 @@ int perf_target__strerror(struct perf_target *target, int errnum,
int idx; int idx;
const char *msg; const char *msg;
BUG_ON(buflen > 0);
if (errnum >= 0) { if (errnum >= 0) {
strerror_r(errnum, buf, buflen); const char *err = strerror_r(errnum, buf, buflen);
if (err != buf) {
size_t len = strlen(err);
char *c = mempcpy(buf, err, min(buflen - 1, len));
*c = '\0';
}
return 0; return 0;
} }