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From: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
To: linux-bluetooth@vger.kernel.org
Cc: oss@ew.tq-group.com,
	Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Subject: [PATCH BlueZ 1/2] tools/rfcomm: reset ignored signals after fork
Date: Thu, 15 Feb 2024 09:39:53 +0100
Message-ID: <20240215083954.5233-1-matthias.schiffer@ew.tq-group.com>
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rfcomm sets SIGCHLD and SIGPIPE to SIG_IGN, which is inherited by child
processes and preserved across execvp(). Many applications do not expect
these signals to be ignored, causing all kinds of breakage (including the
standard C system() function misbehaving on glibc and probably other
libcs because waitpid() does not work when SIGCHLD is ignored).
---
 tools/rfcomm.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/rfcomm.c b/tools/rfcomm.c
index e013ff588..f635d4aef 100644
--- a/tools/rfcomm.c
+++ b/tools/rfcomm.c
@@ -212,6 +212,7 @@ static void run_cmdline(struct pollfd *p, sigset_t *sigs, char *devname,
 	int i;
 	pid_t pid;
 	char **cmdargv;
+	struct sigaction sa;
 
 	cmdargv = malloc((argc + 1) * sizeof(char *));
 	if (!cmdargv)
@@ -225,6 +226,11 @@ static void run_cmdline(struct pollfd *p, sigset_t *sigs, char *devname,
 
 	switch (pid) {
 	case 0:
+		memset(&sa, 0, sizeof(sa));
+		sa.sa_handler = SIG_DFL;
+		sigaction(SIGCHLD, &sa, NULL);
+		sigaction(SIGPIPE, &sa, NULL);
+
 		i = execvp(cmdargv[0], cmdargv);
 		fprintf(stderr, "Couldn't execute command %s (errno=%d:%s)\n",
 				cmdargv[0], errno, strerror(errno));
-- 
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