treewide: use _exit() over exit()

In the podman CI I noticed many seccomp denials in our logs even though
tests passed:
comm="pasta.avx2" exe="/usr/bin/pasta.avx2" sig=31 arch=c000003e
syscall=202 compat=0 ip=0x7fb3d31f69db code=0x80000000

Which is futex being called and blocked by the pasta profile. After a
few tries I managed to reproduce locally with this loop in ~20 min:
while :;
  do podman run -d --network bridge quay.io/libpod/testimage:20241011 \
	sleep 100 && \
  sleep 10 && \
  podman rm -fa -t0
done

And using a pasta version with prctl(PR_SET_DUMPABLE, 1); set I got the
following stack trace:
Stack trace of thread 1:
  #0  0x00007fc95e6de91b __lll_lock_wait_private (libc.so.6 + 0x9491b)
  #1  0x00007fc95e68d6de __run_exit_handlers (libc.so.6 + 0x436de)
  #2  0x00007fc95e68d70e exit (libc.so.6 + 0x4370e)
  #3  0x000055f31b78c50b n/a (n/a + 0x0)
  #4  0x00007fc95e68d70e exit (libc.so.6 + 0x4370e)
  #5  0x000055f31b78d5a2 n/a (n/a + 0x0)

Pasta got killed in exit(), it seems glibc is trying to use a lock when
running exit handlers even though no exit handlers are defined.

Given no exit handlers are needed we can call _exit() instead. This
skips exit handlers and does not flush stdio streams compared to exit()
which should be fine for the use here.

Based on the input from Stefano I did not change the test/doc programs
or qrap as they do not use seccomp filters.

Signed-off-by: Paul Holzinger <pholzing@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/util.c b/util.c
index 800c6b5..4d51e04 100644
--- a/util.c
+++ b/util.c
@@ -405,7 +405,7 @@ void pidfile_write(int fd, pid_t pid)
 
 	if (write(fd, pid_buf, n) < 0) {
 		perror("PID file write");
-		exit(EXIT_FAILURE);
+		_exit(EXIT_FAILURE);
 	}
 
 	close(fd);
@@ -441,12 +441,12 @@ int __daemon(int pidfile_fd, int devnull_fd)
 
 	if (pid == -1) {
 		perror("fork");
-		exit(EXIT_FAILURE);
+		_exit(EXIT_FAILURE);
 	}
 
 	if (pid) {
 		pidfile_write(pidfile_fd, pid);
-		exit(EXIT_SUCCESS);
+		_exit(EXIT_SUCCESS);
 	}
 
 	if (setsid()				< 0 ||
@@ -454,7 +454,7 @@ int __daemon(int pidfile_fd, int devnull_fd)
 	    dup2(devnull_fd, STDOUT_FILENO)	< 0 ||
 	    dup2(devnull_fd, STDERR_FILENO)	< 0 ||
 	    close(devnull_fd))
-		exit(EXIT_FAILURE);
+		_exit(EXIT_FAILURE);
 
 	return 0;
 }