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>
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 4a30c87..96b3ef5 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1029,7 +1029,7 @@
 
 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 @@
 
 		execvp(argv[0], (char **)argv);
 
-		if (want_signal) {
+		if (exec_error) {
 			union sigval val;
 
 			val.sival_int = errno;
@@ -1084,6 +1084,14 @@
 		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;