From: Cristian Rodríguez <crrodriguez@opensuse.org>
Date: Sun, 15 Jan 2023 01:33:14 +0000 (+0000)
Subject: lib:pager: fix signal safety issues
X-Git-Tag: v2.39-rc1~123^2~4
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=518a0ad;p=thirdparty%2Futil-linux.git

lib:pager: fix signal safety issues

- Cannot use stdio in signal handlers, so you cannot safely call
  fflush.
- cannot call exit() but only _exit()
---

diff --git a/lib/pager.c b/lib/pager.c
index e5bd07a471..8f62310c07 100644
--- a/lib/pager.c
+++ b/lib/pager.c
@@ -114,7 +114,9 @@ static int wait_or_whine(pid_t pid)
 		if (waiting < 0) {
 			if (errno == EINTR)
 				continue;
-			err(EXIT_FAILURE, _("waitpid failed (%s)"), strerror(errno));
+			/* Can't err() on signal handler */
+			ignore_result(write(STDERR_FILENO, "waitpid failed", 14));
+			_exit(EXIT_FAILURE);
 		}
 		if (waiting != pid)
 			return -1;
@@ -163,8 +165,6 @@ static void wait_for_pager(void)
 	if (pager_process.pid == 0)
 		return;
 
-	fflush(stdout);
-	fflush(stderr);
 	/* signal EOF to pager */
 	close(STDOUT_FILENO);
 	close(STDERR_FILENO);