hush: make "wait %1" less likely to play with signal mask

Was playing with "sleep 3 | exit 3 & wait %1" and noticed that often
SIGCHLD arrives even before I get to signal masking. Can avoid it in this
case.

function                                             old     new   delta
wait_for_child_or_signal                             228     265     +37

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/shell/hush.c b/shell/hush.c
index ddbf2f7d8b67666d2126c447c21dd3bb3694c053..5e51adfdc09bd5ecf74d0ab2526951faaa307982 100644 (file)
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -8146,11 +8146,11 @@ static void install_fatal_sighandlers(void)
 
        /* We will restore tty pgrp on these signals */
        mask = 0
-               + (1 << SIGILL ) * HUSH_DEBUG
-               + (1 << SIGFPE ) * HUSH_DEBUG
+               /*+ (1 << SIGILL ) * HUSH_DEBUG*/
+               /*+ (1 << SIGFPE ) * HUSH_DEBUG*/
                + (1 << SIGBUS ) * HUSH_DEBUG
                + (1 << SIGSEGV) * HUSH_DEBUG
-               + (1 << SIGTRAP) * HUSH_DEBUG
+               /*+ (1 << SIGTRAP) * HUSH_DEBUG*/
                + (1 << SIGABRT)
        /* bash 3.2 seems to handle these just like 'fatal' ones */
                + (1 << SIGPIPE)
@@ -9518,6 +9518,9 @@ static int wait_for_child_or_signal(struct pipe *waitfor_pipe, pid_t waitfor_pid
                int sig;
                sigset_t oldset;
 
+               if (!sigisemptyset(&G.pending_set))
+                       goto check_sig;
+
                /* waitpid is not interruptible by SA_RESTARTed
                 * signals which we use. Thus, this ugly dance:
                 */
@@ -9532,7 +9535,6 @@ static int wait_for_child_or_signal(struct pipe *waitfor_pipe, pid_t waitfor_pid
 
                if (!sigisemptyset(&G.pending_set)) {
                        /* Crap! we raced with some signal! */
-               //      sig = 0;
                        goto restore;
                }
 
@@ -9567,13 +9569,10 @@ static int wait_for_child_or_signal(struct pipe *waitfor_pipe, pid_t waitfor_pid
                sigsuspend(&oldset);
  restore:
                sigprocmask(SIG_SETMASK, &oldset, NULL);
-
+ check_sig:
                /* So, did we get a signal? */
-               //if (sig > 0)
-               //      raise(sig); /* run handler */
                sig = check_and_run_traps();
                if (sig /*&& sig != SIGCHLD - always true */) {
-                       /* see note 2 */
                        ret = 128 + sig;
                        break;
                }