Reap `xdg-screensaver` correctly

Call waitpid(2) so spawned `xdg-screensaver` processes get reaped.

1 files changed, 8 insertions, 0 deletions

diff --git a/xssxss.c b/xssxss.c
index 17966de..ee15596 100644
--- a/xssxss.c
+++ b/xssxss.c
@@ -21,6 +21,8 @@
 #include <pthread.h>
 #include <signal.h>
 #include <spawn.h>
+#include <sys/types.h>
+#include <sys/wait.h>
 #include <unistd.h>
 
 #include "xssbase.h"
@@ -47,6 +49,9 @@ static void* WakerThreadMain(void* const ignored) {
 
     // Start the process to wake up xscreensaver. When it exits, we'll get
     // SIGCHLD, but we don't care; see notes in `SpawnWakerThread`.
+    //
+    // TODO(bbaren@google.com): Once Linux 5.2 is deployed more widely, switch
+    // to using pidfds.
     pid_t waker_pid;
     char* const waker[] = {"xdg-screensaver", "reset", NULL};
     const int e = posix_spawnp(&waker_pid, waker[0], /*file_action=*/NULL,
@@ -55,6 +60,9 @@ static void* WakerThreadMain(void* const ignored) {
       char buf[128];
       LogDebug("failed to spawn waker: %d", strerror_r(e, buf, 128));
     }
+    if (waitpid(waker_pid, /*wstatus=*/NULL, /*options=*/0) < 0) {
+      LogDebug("failed to wait for waker; continuing");
+    }
     sleep(kWakeupSeconds);
   }