ash: add "wait -n" bashism

function                                             old     new   delta
waitcmd                                              205     288     +83
dowait                                               405     444     +39
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 122/0)             Total: 122 bytes

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

diff --git a/shell/ash.c b/shell/ash.c
index a4394d756a86b09381e5afac8013ce0dd6879d90..b1499b037bfae2160ca1d04e50502410d896a34f 100644 (file)
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -3522,7 +3522,7 @@ struct procstat {
 
 struct job {
        struct procstat ps0;    /* status of process */
-       struct procstat *ps;    /* status or processes when more than one */
+       struct procstat *ps;    /* status of processes when more than one */
 #if JOBS
        int stopstatus;         /* status of a stopped job */
 #endif
@@ -4235,6 +4235,9 @@ wait_block_or_sig(int *status)
 #define DOWAIT_NONBLOCK 0
 #define DOWAIT_BLOCK    1
 #define DOWAIT_BLOCK_OR_SIG 2
+#if ENABLE_ASH_BASH_COMPAT
+# define DOWAIT_JOBSTATUS 0x10   /* OR this to get job's exitstatus instead of pid */
+#endif
 
 static int
 dowait(int block, struct job *job)
@@ -4242,7 +4245,11 @@ dowait(int block, struct job *job)
        int pid;
        int status;
        struct job *jp;
-       struct job *thisjob = NULL;
+       struct job *thisjob;
+#if ENABLE_ASH_BASH_COMPAT
+       bool want_jobexitstatus = (block & DOWAIT_JOBSTATUS);
+       block = (block & ~DOWAIT_JOBSTATUS);
+#endif
 
        TRACE(("dowait(0x%x) called\n", block));
 
@@ -4279,10 +4286,10 @@ dowait(int block, struct job *job)
        }
        TRACE(("wait returns pid=%d, status=0x%x, errno=%d(%s)\n",
                                pid, status, errno, strerror(errno)));
+       thisjob = NULL;
        if (pid <= 0)
                goto out;
 
-       thisjob = NULL;
        for (jp = curjob; jp; jp = jp->prev_job) {
                int jobstate;
                struct procstat *ps;
@@ -4341,6 +4348,13 @@ dowait(int block, struct job *job)
  out:
        INT_ON;
 
+#if ENABLE_ASH_BASH_COMPAT
+       if (want_jobexitstatus) {
+               pid = -1;
+               if (thisjob && thisjob->state == JOBDONE)
+                       pid = thisjob->ps[thisjob->nprocs - 1].ps_status;
+       }
+#endif
        if (thisjob && thisjob == job) {
                char s[48 + 1];
                int len;
@@ -4523,15 +4537,24 @@ waitcmd(int argc UNUSED_PARAM, char **argv)
        struct job *job;
        int retval;
        struct job *jp;
-
+#if ENABLE_ASH_BASH_COMPAT
+       int status;
+       char one = nextopt("n");
+#else
        nextopt(nullstr);
+#endif
        retval = 0;
 
        argv = argptr;
-       if (!*argv) {
-               /* wait for all jobs */
+       if (!argv[0]) {
+               /* wait for all jobs / one job if -n */
                for (;;) {
                        jp = curjob;
+#if ENABLE_ASH_BASH_COMPAT
+                       if (one && !jp)
+                               /* exitcode of "wait -n" with nothing to wait for is 127, not 0 */
+                               retval = 127;
+#endif
                        while (1) {
                                if (!jp) /* no running procs */
                                        goto ret;
@@ -4547,13 +4570,31 @@ waitcmd(int argc UNUSED_PARAM, char **argv)
         * with an exit status greater than 128, immediately after which
         * the trap is executed."
         */
+#if ENABLE_ASH_BASH_COMPAT
+                       status = dowait(DOWAIT_BLOCK_OR_SIG | DOWAIT_JOBSTATUS, NULL);
+#else
                        dowait(DOWAIT_BLOCK_OR_SIG, NULL);
+#endif
        /* if child sends us a signal *and immediately exits*,
         * dowait() returns pid > 0. Check this case,
         * not "if (dowait() < 0)"!
         */
                        if (pending_sig)
                                goto sigout;
+#if ENABLE_ASH_BASH_COMPAT
+                       if (one) {
+                               /* wait -n waits for one _job_, not one _process_.
+                                *  date; sleep 3 & sleep 2 | sleep 1 & wait -n; date
+                                * should wait for 2 seconds. Not 1 or 3.
+                                */
+                               if (status != -1 && !WIFSTOPPED(status)) {
+                                       retval = WEXITSTATUS(status);
+                                       if (WIFSIGNALED(status))
+                                               retval = WTERMSIG(status) + 128;
+                                       goto ret;
+                               }
+                       }
+#endif
                }
        }