perf evlist: Send the errno in the signal when workload fails

When a tool uses perf_evlist__start_workload and the supplied workload
fails (e.g.: its binary wasn't found), perror was being used to print
the error reason.

This is undesirable, as the caller may be a GUI, when it wants to have
total control of the error reporting process.

So move to using sigaction(SA_SIGINFO) + siginfo_t->sa_value->sival_int
to communicate to the caller the errno and let it print it using the UI
of its choosing.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-epgcv7kjq8ll2udqfken92pz@git.kernel.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 6af206fd
......@@ -341,6 +341,22 @@ static void record__init_features(struct record *rec)
perf_header__clear_feat(&session->header, HEADER_BRANCH_STACK);
}
static volatile int workload_exec_errno;
/*
* perf_evlist__prepare_workload will send a SIGUSR1
* if the fork fails, since we asked by setting its
* want_signal to true.
*/
static void workload_exec_failed_signal(int signo, siginfo_t *info,
void *ucontext __maybe_unused)
{
workload_exec_errno = info->si_value.sival_int;
done = 1;
signr = signo;
child_finished = 1;
}
static int __cmd_record(struct record *rec, int argc, const char **argv)
{
int err;
......@@ -359,7 +375,6 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
on_exit(record__sig_exit, rec);
signal(SIGCHLD, sig_handler);
signal(SIGINT, sig_handler);
signal(SIGUSR1, sig_handler);
signal(SIGTERM, sig_handler);
session = perf_session__new(file, false, NULL);
......@@ -492,8 +507,20 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
/*
* Let the child rip
*/
if (forks)
if (forks) {
struct sigaction act = {
.sa_flags = SA_SIGINFO,
.sa_sigaction = workload_exec_failed_signal,
};
/*
* perf_evlist__prepare_workload will, after we call
* perf_evlist__start_Workload, send a SIGUSR1 if the exec call
* fails, that we will catch in workload_signal to flip
* workload_exec_errno.
*/
sigaction(SIGUSR1, &act, NULL);
perf_evlist__start_workload(evsel_list);
}
for (;;) {
int hits = rec->samples;
......@@ -521,6 +548,14 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
}
}
if (forks && workload_exec_errno) {
char msg[512];
const char *emsg = strerror_r(workload_exec_errno, msg, sizeof(msg));
pr_err("Workload failed: %s\n", emsg);
err = -1;
goto out_delete_session;
}
if (quiet || signr == SIGUSR1)
return 0;
......
......@@ -58,6 +58,7 @@
#include "util/thread.h"
#include "util/thread_map.h"
#include <signal.h>
#include <stdlib.h>
#include <sys/prctl.h>
#include <locale.h>
......@@ -509,16 +510,17 @@ static void handle_initial_delay(void)
}
}
static volatile bool workload_exec_failed;
static volatile int workload_exec_errno;
/*
* perf_evlist__prepare_workload will send a SIGUSR1
* if the fork fails, since we asked by setting its
* want_signal to true.
*/
static void workload_exec_failed_signal(int signo __maybe_unused)
static void workload_exec_failed_signal(int signo __maybe_unused, siginfo_t *info,
void *ucontext __maybe_unused)
{
workload_exec_failed = true;
workload_exec_errno = info->si_value.sival_int;
}
static int __run_perf_stat(int argc, const char **argv)
......@@ -596,13 +598,17 @@ static int __run_perf_stat(int argc, const char **argv)
clock_gettime(CLOCK_MONOTONIC, &ref_time);
if (forks) {
struct sigaction act = {
.sa_flags = SA_SIGINFO,
.sa_sigaction = workload_exec_failed_signal,
};
/*
* perf_evlist__prepare_workload will, after we call
* perf_evlist__start_Workload, send a SIGUSR1 if the exec call
* fails, that we will catch in workload_signal to flip
* workload_exec_failed.
* workload_exec_errno.
*/
signal(SIGUSR1, workload_exec_failed_signal);
sigaction(SIGUSR1, &act, NULL);
perf_evlist__start_workload(evsel_list);
handle_initial_delay();
......@@ -615,8 +621,11 @@ static int __run_perf_stat(int argc, const char **argv)
}
wait(&status);
if (workload_exec_failed)
if (workload_exec_errno) {
const char *emsg = strerror_r(workload_exec_errno, msg, sizeof(msg));
pr_err("Workload failed: %s\n", emsg);
return -1;
}
if (WIFSIGNALED(status))
psignal(WTERMSIG(status), argv[0]);
......
......@@ -1073,9 +1073,14 @@ int perf_evlist__prepare_workload(struct perf_evlist *evlist, struct target *tar
execvp(argv[0], (char **)argv);
perror(argv[0]);
if (want_signal)
kill(getppid(), SIGUSR1);
if (want_signal) {
union sigval val;
val.sival_int = errno;
if (sigqueue(getppid(), SIGUSR1, val))
perror(argv[0]);
} else
perror(argv[0]);
exit(-1);
}
......
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