Valtteri reports that if SIGPIPE already has a disposition set by the parent process, such as systemd with the default setting of IgnoreSIGPIPE=yes, signal() will return the previous value, not zero, and this is not an error: check for SIG_ERR instead. While at it, split messages for failures of sigaction() and signal(), and report the actual error. Reported-by: Valtteri Vuorikoski Fixes: 8534be076c73 ("Catch failures when installing signal handlers") Signed-off-by: Stefano Brivio --- passt.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/passt.c b/passt.c index 7fa1170..3b9b36b 100644 --- a/passt.c +++ b/passt.c @@ -204,8 +204,15 @@ int main(int argc, char **argv) name = basename(argv0); if (strstr(name, "pasta")) { sa.sa_handler = pasta_child_handler; - if (sigaction(SIGCHLD, &sa, NULL) || signal(SIGPIPE, SIG_IGN)) - die("Couldn't install signal handlers"); + if (sigaction(SIGCHLD, &sa, NULL)) { + die("Couldn't install signal handlers: %s", + strerror(errno)); + } + + if (signal(SIGPIPE, SIG_IGN) == SIG_ERR) { + die("Couldn't set disposition for SIGPIPE: %s", + strerror(errno)); + } c.mode = MODE_PASTA; log_name = "pasta"; -- 2.39.2