[git commit] hush: make "wait %1" less likely to play with signal mask
Denys Vlasenko
vda.linux at googlemail.com
Tue Nov 8 03:59:11 UTC 2016
commit: https://git.busybox.net/busybox/commit/?id=830ea35484cecb8b4cdbe0f30cc5d573ff0e3411
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master
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 at googlemail.com>
---
shell/hush.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/shell/hush.c b/shell/hush.c
index ddbf2f7..5e51adf 100644
--- 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;
}
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