Do not create zombie processes in perfetto_hprof.
We now daemonize after forking to reparent the perfetto_hprof process
to init. ART now waits on the intermediate process, which immediately
exits, before resuming the prevent creating a zombie.
Bug: 148280975
Test: run profile, then `adb shell ps -A | grep Z`
Change-Id: I8d101331375a5542de58bfd0f4e54b8281d0a3a2
diff --git a/perfetto_hprof/perfetto_hprof.cc b/perfetto_hprof/perfetto_hprof.cc
index ce2f7b2db..4f20094 100644
--- a/perfetto_hprof/perfetto_hprof.cc
+++ b/perfetto_hprof/perfetto_hprof.cc
@@ -25,6 +25,7 @@
#include <signal.h>
#include <sys/stat.h>
#include <sys/types.h>
+#include <sys/wait.h>
#include <thread>
#include <time.h>
@@ -363,9 +364,30 @@
art::ScopedSuspendAll ssa(__FUNCTION__, /* long_suspend=*/ true);
pid_t pid = fork();
- if (pid != 0) {
+ if (pid == -1) {
+ // Fork error.
+ PLOG(ERROR) << "fork";
return;
}
+ if (pid != 0) {
+ // Parent
+ int stat_loc;
+ for (;;) {
+ if (waitpid(pid, &stat_loc, 0) != -1 || errno != EINTR) {
+ break;
+ }
+ }
+ return;
+ }
+
+ // The following code is only executed by the child of the original process.
+ //
+ // Daemon creates a new process that is the grand-child of the original process, and exits.
+ if (daemon(0, 0) == -1) {
+ PLOG(FATAL) << "daemon";
+ }
+
+ // The following code is only executed by the grand-child of the original process.
// Make sure that this is the first thing we do after forking, so if anything
// below hangs, the fork will go away from the watchdog.
