Make signal setup clearer via helper function, eliminating a gap in

ignoring signals when they were already ignored

ok millert@

diff --git a/bin/pax/pax.c b/bin/pax/pax.c
index abb6ecb..f342508 100644 (file)
--- a/bin/pax/pax.c
+++ b/bin/pax/pax.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: pax.c,v 1.36 2014/05/23 19:47:49 guenther Exp $       */
+/*     $OpenBSD: pax.c,v 1.37 2014/05/24 03:49:49 guenther Exp $       */
 /*     $NetBSD: pax.c,v 1.5 1996/03/26 23:54:20 mrg Exp $      */
 
 /*-
@@ -317,6 +317,25 @@ sig_cleanup(int which_sig)
        _exit(1);
 }
 
+/*
+ * setup_sig()
+ *     set a signal to be caught, but only if it isn't being ignored already
+ */
+
+static int
+setup_sig(int sig, const struct sigaction *n_hand)
+{
+       struct sigaction o_hand;
+
+       if (sigaction(sig, NULL, &o_hand) < 0)
+               return (-1);
+
+       if (o_hand.sa_handler == SIG_IGN)
+               return (0);
+
+       return (sigaction(sig, n_hand, NULL));
+}
+
 /*
  * gen_init()
  *     general setup routines. Not all are required, but they really help
@@ -328,7 +347,6 @@ gen_init(void)
 {
        struct rlimit reslimit;
        struct sigaction n_hand;
-       struct sigaction o_hand;
 
        /*
         * Really needed to handle large archives. We can run out of memory for
@@ -386,34 +404,16 @@ gen_init(void)
        n_hand.sa_flags = 0;
        n_hand.sa_handler = sig_cleanup;
 
-       if ((sigaction(SIGHUP, &n_hand, &o_hand) < 0) ||
-           (o_hand.sa_handler == SIG_IGN) &&
-           (sigaction(SIGHUP, &o_hand, &o_hand) < 0))
-               goto out;
-
-       if ((sigaction(SIGTERM, &n_hand, &o_hand) < 0) ||
-           (o_hand.sa_handler == SIG_IGN) &&
-           (sigaction(SIGTERM, &o_hand, &o_hand) < 0))
-               goto out;
-
-       if ((sigaction(SIGINT, &n_hand, &o_hand) < 0) ||
-           (o_hand.sa_handler == SIG_IGN) &&
-           (sigaction(SIGINT, &o_hand, &o_hand) < 0))
-               goto out;
-
-       if ((sigaction(SIGQUIT, &n_hand, &o_hand) < 0) ||
-           (o_hand.sa_handler == SIG_IGN) &&
-           (sigaction(SIGQUIT, &o_hand, &o_hand) < 0))
-               goto out;
-
-       if ((sigaction(SIGXCPU, &n_hand, &o_hand) < 0) ||
-           (o_hand.sa_handler == SIG_IGN) &&
-           (sigaction(SIGXCPU, &o_hand, &o_hand) < 0))
+       if (setup_sig(SIGHUP,  &n_hand) ||
+           setup_sig(SIGTERM, &n_hand) ||
+           setup_sig(SIGINT,  &n_hand) ||
+           setup_sig(SIGQUIT, &n_hand) ||
+           setup_sig(SIGXCPU, &n_hand))
                goto out;
 
        n_hand.sa_handler = SIG_IGN;
-       if ((sigaction(SIGPIPE, &n_hand, &o_hand) < 0) ||
-           (sigaction(SIGXFSZ, &n_hand, &o_hand) < 0))
+       if ((sigaction(SIGPIPE, &n_hand, NULL) < 0) ||
+           (sigaction(SIGXFSZ, &n_hand, NULL) < 0))
                goto out;
        return(0);