rootless: avoid zombie process on first launch

avoid a zombie process if on the first launch Podman creates a long
living process, such as "podman system service -t 0".

The `r` variable was overriden thus causing the waitpid to fail and
not clean up the intermediate process.

Closes: https://github.com/containers/podman/issues/10575

[NO TESTS NEEDED]

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

1 files changed, 15 insertions, 10 deletions

diff --git a/pkg/rootless/rootless_linux.c b/pkg/rootless/rootless_linux.c
index e5f9e88d9..4d8443fcb 100644
--- a/pkg/rootless/rootless_linux.c
+++ b/pkg/rootless/rootless_linux.c
@@ -465,38 +465,43 @@ reexec_in_user_namespace_wait (int pid, int options)
 static int
 create_pause_process (const char *pause_pid_file_path, char **argv)
 {
-  int r, p[2];
+  pid_t pid;
+  int p[2];
 
   if (pipe (p) < 0)
-    _exit (EXIT_FAILURE);
+    return -1;
 
-  r = fork ();
-  if (r < 0)
-    _exit (EXIT_FAILURE);
+  pid = fork ();
+  if (pid < 0)
+    {
+      close (p[0]);
+      close (p[1]);
+      return -1;
+    }
 
-  if (r)
+  if (pid)
     {
       char b;
+      int r;
 
       close (p[1]);
       /* Block until we write the pid file.  */
       r = TEMP_FAILURE_RETRY (read (p[0], &b, 1));
       close (p[0]);
 
-      reexec_in_user_namespace_wait (r, 0);
+      reexec_in_user_namespace_wait (pid, 0);
 
       return r == 1 && b == '0' ? 0 : -1;
     }
   else
     {
-      int fd;
-      pid_t pid;
+      int r, fd;
 
       close (p[0]);
 
       setsid ();
       pid = fork ();
-      if (r < 0)
+      if (pid < 0)
         _exit (EXIT_FAILURE);
 
       if (pid)