Avoid getting stuck in system(3) when the internal call to wait4()

is interrupted by saving the pid.

The old code would assign the return value to pid which would trash
it, to fix the problem save a copy of the pid to be used as the
paramter to wait4().

Submitted by: Toshihiko ARAI <toshi@jp.FreeBSD.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/lib/libc/stdlib/system.c b/lib/libc/stdlib/system.c
index 3b16454..28c9617 100644
--- a/lib/libc/stdlib/system.c
+++ b/lib/libc/stdlib/system.c
@@ -53,7 +53,7 @@ int
 __system(command)
 	const char *command;
 {
-	pid_t pid;
+	pid_t pid, savedpid;
 	int pstat;
 	struct sigaction ign, intact, quitact;
 	sigset_t newsigblock, oldsigblock;
@@ -86,8 +86,9 @@ __system(command)
 		execl(_PATH_BSHELL, "sh", "-c", command, (char *)NULL);
 		_exit(127);
 	default:			/* parent */
+		savedpid = pid;
 		do {
-			pid = _wait4(pid, &pstat, 0, (struct rusage *)0);
+			pid = _wait4(savedpid, &pstat, 0, (struct rusage *)0);
 		} while (pid == -1 && errno == EINTR);
 		break;
 	}