linux/tools/perf/util/cloexec.c
Masami Hiramatsu 6e81c74cbf perf util: Replace strerror with strerror_r for thread-safety
Replaces all strerror with strerror_r in util for making the perf lib
thread-safe.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naohiro Aota <naota@elisp.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20140814022236.3545.3367.stgit@kbuild-fedora.novalocal
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-08-15 10:58:35 -03:00

75 lines
1.4 KiB
C

#include <sched.h>
#include "util.h"
#include "../perf.h"
#include "cloexec.h"
#include "asm/bug.h"
#include "debug.h"
static unsigned long flag = PERF_FLAG_FD_CLOEXEC;
static int perf_flag_probe(void)
{
/* use 'safest' configuration as used in perf_evsel__fallback() */
struct perf_event_attr attr = {
.type = PERF_TYPE_SOFTWARE,
.config = PERF_COUNT_SW_CPU_CLOCK,
.exclude_kernel = 1,
};
int fd;
int err;
int cpu;
pid_t pid = -1;
char sbuf[STRERR_BUFSIZE];
cpu = sched_getcpu();
if (cpu < 0)
cpu = 0;
while (1) {
/* check cloexec flag */
fd = sys_perf_event_open(&attr, pid, cpu, -1,
PERF_FLAG_FD_CLOEXEC);
if (fd < 0 && pid == -1 && errno == EACCES) {
pid = 0;
continue;
}
break;
}
err = errno;
if (fd >= 0) {
close(fd);
return 1;
}
WARN_ONCE(err != EINVAL && err != EBUSY,
"perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error %d (%s)\n",
err, strerror_r(err, sbuf, sizeof(sbuf)));
/* not supported, confirm error related to PERF_FLAG_FD_CLOEXEC */
fd = sys_perf_event_open(&attr, pid, cpu, -1, 0);
err = errno;
if (WARN_ONCE(fd < 0 && err != EBUSY,
"perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n",
err, strerror_r(err, sbuf, sizeof(sbuf))))
return -1;
close(fd);
return 0;
}
unsigned long perf_event_open_cloexec_flag(void)
{
static bool probed;
if (!probed) {
if (perf_flag_probe() <= 0)
flag = 0;
probed = true;
}
return flag;
}