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

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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>
This commit is contained in:
Denys Vlasenko 2016-11-08 04:59:11 +01:00
parent 02affb4afd
commit 830ea35484
1 changed files with 7 additions and 8 deletions
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15
shell/hush.c
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@ -8146,11 +8146,11 @@ static void install_fatal_sighandlers(void)
/* We will restore tty pgrp on these signals */ /* We will restore tty pgrp on these signals */
mask = 0 mask = 0
+ (1 << SIGILL ) * HUSH_DEBUG /*+ (1 << SIGILL ) * HUSH_DEBUG*/
+ (1 << SIGFPE ) * HUSH_DEBUG /*+ (1 << SIGFPE ) * HUSH_DEBUG*/
+ (1 << SIGBUS ) * HUSH_DEBUG + (1 << SIGBUS ) * HUSH_DEBUG
+ (1 << SIGSEGV) * HUSH_DEBUG + (1 << SIGSEGV) * HUSH_DEBUG
+ (1 << SIGTRAP) * HUSH_DEBUG /*+ (1 << SIGTRAP) * HUSH_DEBUG*/
+ (1 << SIGABRT) + (1 << SIGABRT)
/* bash 3.2 seems to handle these just like 'fatal' ones */ /* bash 3.2 seems to handle these just like 'fatal' ones */
+ (1 << SIGPIPE) + (1 << SIGPIPE)
@ -9518,6 +9518,9 @@ static int wait_for_child_or_signal(struct pipe *waitfor_pipe, pid_t waitfor_pid
int sig; int sig;
sigset_t oldset; sigset_t oldset;
if (!sigisemptyset(&G.pending_set))
goto check_sig;
/* waitpid is not interruptible by SA_RESTARTed /* waitpid is not interruptible by SA_RESTARTed
* signals which we use. Thus, this ugly dance: * 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)) { if (!sigisemptyset(&G.pending_set)) {
/* Crap! we raced with some signal! */ /* Crap! we raced with some signal! */
// sig = 0;
goto restore; goto restore;
} }
@ -9567,13 +9569,10 @@ static int wait_for_child_or_signal(struct pipe *waitfor_pipe, pid_t waitfor_pid
sigsuspend(&oldset); sigsuspend(&oldset);
restore: restore:
sigprocmask(SIG_SETMASK, &oldset, NULL); sigprocmask(SIG_SETMASK, &oldset, NULL);
check_sig:
/* So, did we get a signal? */ /* So, did we get a signal? */
//if (sig > 0)
// raise(sig); /* run handler */
sig = check_and_run_traps(); sig = check_and_run_traps();
if (sig /*&& sig != SIGCHLD - always true */) { if (sig /*&& sig != SIGCHLD - always true */) {
/* see note 2 */
ret = 128 + sig; ret = 128 + sig;
break; break;
} }