perf evlist: Move the SIGUSR1 error reporting logic to prepare_workload

So that we have the boilerplate in the preparation method, instead of
open coded in tools wanting the reporting when the exec fails.

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-purbdzcphdveskh7wwmnm4t7@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

7 files changed, 32 insertions, 40 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index f987d385c6f0..ea7c3060e8e7 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -390,7 +390,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
         if (forks) {
                 err = perf_evlist__prepare_workload(evsel_list, &opts->target,
                                                     argv, file->is_pipe,
-                                                    true);
+                                                    workload_exec_failed_signal);
                 if (err < 0) {
                         pr_err("Couldn't run the workload!\n");
                         goto out_delete_session;
@@ -507,20 +507,8 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
         /*
          * Let the child rip
          */
-        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);
+        if (forks)
                 perf_evlist__start_workload(evsel_list);
-        }
 
         for (;;) {
                 int hits = rec->samples;
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 9d0d52d55ee6..f8456cad656d 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -58,7 +58,6 @@
 #include "util/thread.h"
 #include "util/thread_map.h"
 
-#include <signal.h>
 #include <stdlib.h>
 #include <sys/prctl.h>
 #include <locale.h>
@@ -542,8 +541,8 @@ static int __run_perf_stat(int argc, const char **argv)
         }
 
         if (forks) {
-                if (perf_evlist__prepare_workload(evsel_list, &target, argv,
-                                                  false, true) < 0) {
+                if (perf_evlist__prepare_workload(evsel_list, &target, argv, false,
+                                                  workload_exec_failed_signal) < 0) {
                         perror("failed to prepare workload");
                         return -1;
                 }
@@ -598,18 +597,6 @@ 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_errno.
-                 */
-                sigaction(SIGUSR1, &act, NULL);
-
                 perf_evlist__start_workload(evsel_list);
                 handle_initial_delay();
 
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index c5b4bc51175c..5498eacf8fc6 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -1895,7 +1895,7 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
 
         if (forks) {
                 err = perf_evlist__prepare_workload(evlist, &trace->opts.target,
-                                                    argv, false, false);
+                                                    argv, false, NULL);
                 if (err < 0) {
                         fprintf(trace->output, "Couldn't run the workload!\n");
                         goto out_delete_maps;
diff --git a/tools/perf/tests/perf-record.c b/tools/perf/tests/perf-record.c
index eeba562920e9..fa0ed35afb9a 100644
--- a/tools/perf/tests/perf-record.c
+++ b/tools/perf/tests/perf-record.c
@@ -83,8 +83,7 @@ int test__PERF_RECORD(void)
          * so that we have time to open the evlist (calling sys_perf_event_open
          * on all the fds) and then mmap them.
          */
-        err = perf_evlist__prepare_workload(evlist, &opts.target, argv,
-                                            false, false);
+        err = perf_evlist__prepare_workload(evlist, &opts.target, argv, false, NULL);
         if (err < 0) {
                 pr_debug("Couldn't run the workload!\n");
                 goto out_delete_maps;
diff --git a/tools/perf/tests/task-exit.c b/tools/perf/tests/task-exit.c
index d09ab579119e..44e339d4e297 100644
--- a/tools/perf/tests/task-exit.c
+++ b/tools/perf/tests/task-exit.c
@@ -9,12 +9,21 @@
 static int exited;
 static int nr_exit;
 
-static void sig_handler(int sig)
+static void sig_handler(int sig __maybe_unused)
 {
         exited = 1;
+}
 
-        if (sig == SIGUSR1)
-                nr_exit = -1;
+/*
+ * perf_evlist__prepare_workload will send a SIGUSR1 if the fork fails, since
+ * we asked by setting its exec_error to this handler.
+ */
+static void workload_exec_failed_signal(int signo __maybe_unused,
+                                        siginfo_t *info __maybe_unused,
+                                        void *ucontext __maybe_unused)
+{
+        exited  = 1;
+        nr_exit = -1;
 }
 
 /*
@@ -35,7 +44,6 @@ int test__task_exit(void)
         const char *argv[] = { "true", NULL };
 
         signal(SIGCHLD, sig_handler);
-        signal(SIGUSR1, sig_handler);
 
         evlist = perf_evlist__new_default();
         if (evlist == NULL) {
@@ -57,7 +65,8 @@ int test__task_exit(void)
                 goto out_delete_maps;
         }
 
-        err = perf_evlist__prepare_workload(evlist, &target, argv, false, true);
+        err = perf_evlist__prepare_workload(evlist, &target, argv, false,
+                                            workload_exec_failed_signal);
         if (err < 0) {
                 pr_debug("Couldn't run the workload!\n");
                 goto out_delete_maps;
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 4a30c87d24ec..96b3ef547db4 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1029,7 +1029,7 @@ out_err:
 
 int perf_evlist__prepare_workload(struct perf_evlist *evlist, struct target *target,
                                   const char *argv[], bool pipe_output,
-                                  bool want_signal)
+                                  void (*exec_error)(int signo, siginfo_t *info, void *ucontext))
 {
         int child_ready_pipe[2], go_pipe[2];
         char bf;
@@ -1073,7 +1073,7 @@ int perf_evlist__prepare_workload(struct perf_evlist *evlist, struct target *tar
 
                 execvp(argv[0], (char **)argv);
 
-                if (want_signal) {
+                if (exec_error) {
                         union sigval val;
 
                         val.sival_int = errno;
@@ -1084,6 +1084,14 @@ int perf_evlist__prepare_workload(struct perf_evlist *evlist, struct target *tar
                 exit(-1);
         }
 
+        if (exec_error) {
+                struct sigaction act = {
+                        .sa_flags     = SA_SIGINFO,
+                        .sa_sigaction = exec_error,
+                };
+                sigaction(SIGUSR1, &act, NULL);
+        }
+
         if (target__none(target))
                 evlist->threads->map[0] = evlist->workload.pid;
 
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 2fe51958ed85..18d1222c0762 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -103,7 +103,8 @@ int record_opts__config(struct record_opts *opts);
 int perf_evlist__prepare_workload(struct perf_evlist *evlist,
                                   struct target *target,
                                   const char *argv[], bool pipe_output,
-                                  bool want_signal);
+                                  void (*exec_error)(int signo, siginfo_t *info,
+                                                     void *ucontext));
 int perf_evlist__start_workload(struct perf_evlist *evlist);
 
 int perf_evlist__parse_mmap_pages(const struct option *opt,