priv: use `sigaction()` instead of `signal()` to install non-default signals

`signal()` is not portable to install non-default signals.

diff --git a/src/daemon/priv.c b/src/daemon/priv.c
index 6b65e9110f44064d4c7c42659e445b75428d81f8..c5e630aea7cd9fc412a2a89e5c39837f31ed8d96 100644 (file)
--- a/src/daemon/priv.c
+++ b/src/daemon/priv.c
@@ -492,12 +492,22 @@ priv_init(const char *chrootdir, int ctl, uid_t uid, gid_t gid)
                if (atexit(priv_exit) != 0)
                        fatal("privsep", "unable to set exit function");
 
-               signal(SIGALRM, sig_pass_to_chld);
-               signal(SIGTERM, sig_pass_to_chld);
-               signal(SIGHUP, sig_pass_to_chld);
-               signal(SIGINT, sig_pass_to_chld);
-               signal(SIGQUIT, sig_pass_to_chld);
-               signal(SIGCHLD, sig_chld);
+               /* Install signal handlers */
+               const struct sigaction pass_to_child = {
+                       .sa_handler = sig_pass_to_chld,
+                       .sa_flags = SA_RESTART
+               };
+               sigaction(SIGALRM, &pass_to_child, NULL);
+               sigaction(SIGTERM, &pass_to_child, NULL);
+               sigaction(SIGHUP,  &pass_to_child, NULL);
+               sigaction(SIGINT,  &pass_to_child, NULL);
+               sigaction(SIGQUIT, &pass_to_child, NULL);
+               const struct sigaction child = {
+                       .sa_handler = sig_chld,
+                       .sa_flags = SA_RESTART
+               };
+               sigaction(SIGCHLD, &child, NULL);
+
                 if (waitpid(monitored, &status, WNOHANG) != 0)
                         /* Child is already dead */
                         _exit(1);