From: Tobias Stoeckmann <tobias@stoeckmann.org>
Date: Mon, 2 Feb 2026 19:07:35 +0000 (+0100)
Subject: lib/pager: Set SIGCHLD to default handling
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f62eeeb2582889e5aeed1f8acca826bac272f4d8;p=thirdparty%2Futil-linux.git

lib/pager: Set SIGCHLD to default handling

If SIGCHLD is ignored, then waitpid might return an error if child
process is already terminated, since zombie process generation would be
blocked.

Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>
---

diff --git a/lib/pager.c b/lib/pager.c
index 9cbf6383f..de4c2113c 100644
--- a/lib/pager.c
+++ b/lib/pager.c
@@ -35,6 +35,7 @@ struct child_process {
 
 	int org_err;
 	int org_out;
+	struct sigaction orig_sigchld;
 	struct sigaction orig_sigint;
 	struct sigaction orig_sighup;
 	struct sigaction orig_sigterm;
@@ -186,6 +187,12 @@ static void __setup_pager(void)
 	pager_process.argv = pager_argv;
 	pager_process.in = -1;
 
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_handler = SIG_DFL;
+
+	/* this makes sure that waitpid works as expected */
+	sigaction(SIGCHLD, &sa, &pager_process.orig_sigchld);
+
 	if (start_command(&pager_process))
 		return;
 
@@ -198,7 +205,6 @@ static void __setup_pager(void)
 	}
 	close(pager_process.in);
 
-	memset(&sa, 0, sizeof(sa));
 	sa.sa_handler = wait_for_pager_signal;
 
 	/* this makes sure that the parent terminates after the pager */
@@ -251,6 +257,7 @@ void pager_close(void)
 	close(pager_process.org_err);
 
 	/* restore original signal settings */
+	sigaction(SIGCHLD, &pager_process.orig_sigchld, NULL);
 	sigaction(SIGINT,  &pager_process.orig_sigint, NULL);
 	sigaction(SIGHUP,  &pager_process.orig_sighup, NULL);
 	sigaction(SIGTERM, &pager_process.orig_sigterm, NULL);