diff options
| -rw-r--r-- | shell/ash.c | 91 |
1 files changed, 34 insertions, 57 deletions
diff --git a/shell/ash.c b/shell/ash.c index 13470b2..07aa2da 100644 --- a/shell/ash.c +++ b/shell/ash.c @@ -4273,64 +4273,55 @@ sprint_status48(char *os, int status, int sigonly) return s - os; } +#define DOWAIT_NONBLOCK 0 +#define DOWAIT_BLOCK 1 +#define DOWAIT_BLOCK_OR_SIG 2 +#if BASH_WAIT_N +# define DOWAIT_JOBSTATUS 0x10 /* OR this to get job's exitstatus instead of pid */ +#endif + static int -wait_block_or_sig(int *status) +waitproc(int block, int *status) { - int pid; + sigset_t oldmask; + int flags = block == DOWAIT_BLOCK ? 0 : WNOHANG; + int err; - do { - sigset_t mask; +#if JOBS + if (doing_jobctl) + flags |= WUNTRACED; +#endif - /* Poll all children for changes in their state */ + do { got_sigchld = 0; - /* if job control is active, accept stopped processes too */ - pid = waitpid(-1, status, doing_jobctl ? (WNOHANG|WUNTRACED) : WNOHANG); - if (pid != 0) - break; /* Error (e.g. EINTR, ECHILD) or pid */ + do + err = waitpid(-1, status, flags); + while (err < 0 && errno == EINTR); - /* Children exist, but none are ready. Sleep until interesting signal */ -#if 1 - sigfillset(&mask); - sigprocmask2(SIG_SETMASK, &mask); /* mask is updated */ - while (!got_sigchld && !pending_sig) { - sigsuspend(&mask); - /* ^^^ add "sigdelset(&mask, SIGCHLD);" before sigsuspend - * to make sure SIGCHLD is not masked off? - * It was reported that this: - * fn() { : | return; } - * shopt -s lastpipe - * fn - * exec ash SCRIPT - * under bash 4.4.23 runs SCRIPT with SIGCHLD masked, - * making "wait" commands in SCRIPT block forever. - */ - } - sigprocmask(SIG_SETMASK, &mask, NULL); -#else /* unsafe: a signal can set pending_sig after check, but before pause() */ + if (err || (err = -!block)) + break; + + sigfillset(&oldmask); + sigprocmask2(SIG_SETMASK, &oldmask); /* mask is updated */ while (!got_sigchld && !pending_sig) - pause(); -#endif + sigsuspend(&oldmask); + sigprocmask(SIG_SETMASK, &oldmask, NULL); + //simpler, but unsafe: a signal can set pending_sig after check, but before pause(): + //while (!got_sigchld && !pending_sig) + // pause(); - /* If it was SIGCHLD, poll children again */ } while (got_sigchld); - return pid; + return err; } -#define DOWAIT_NONBLOCK 0 -#define DOWAIT_BLOCK 1 -#define DOWAIT_BLOCK_OR_SIG 2 -#if BASH_WAIT_N -# define DOWAIT_JOBSTATUS 0x10 /* OR this to get job's exitstatus instead of pid */ -#endif - static int waitone(int block, struct job *job) { int pid; int status; struct job *jp; - struct job *thisjob; + struct job *thisjob = NULL; #if BASH_WAIT_N bool want_jobexitstatus = (block & DOWAIT_JOBSTATUS); block = (block & ~DOWAIT_JOBSTATUS); @@ -4357,21 +4348,8 @@ waitone(int block, struct job *job) * SIG_DFL handler does not wake sigsuspend(). */ INT_OFF; - if (block == DOWAIT_BLOCK_OR_SIG) { - pid = wait_block_or_sig(&status); - } else { - int wait_flags = 0; - if (block == DOWAIT_NONBLOCK) - wait_flags = WNOHANG; - /* if job control is active, accept stopped processes too */ - if (doing_jobctl) - wait_flags |= WUNTRACED; - /* NB: _not_ safe_waitpid, we need to detect EINTR */ - pid = waitpid(-1, &status, wait_flags); - } - TRACE(("wait returns pid=%d, status=0x%x, errno=%d(%s)\n", - pid, status, errno, strerror(errno))); - thisjob = NULL; + pid = waitproc(block, &status); + TRACE(("wait returns pid %d, status=%d\n", pid, status)); if (pid <= 0) goto out; @@ -4466,7 +4444,6 @@ dowait(int block, struct job *jp) rpid = 1; do { - got_sigchld = 0; pid = waitone(block, jp); rpid &= !!pid; @@ -4721,7 +4698,7 @@ waitcmd(int argc UNUSED_PARAM, char **argv) job = getjob(*argv, 0); } /* loop until process terminated or stopped */ - dowait(DOWAIT_BLOCK_OR_SIG, NULL); + dowait(DOWAIT_BLOCK_OR_SIG, job); if (pending_sig) goto sigout; job->waited = 1; |