hush: add "wait -n" bashism

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

1 files changed, 17 insertions, 1 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 920a85299..7c907686e 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -8763,7 +8763,11 @@ static int checkjobs(struct pipe *fg_pipe, pid_t waitfor_pid)
                         /* fg_pipe exited or stopped */
                         break;
                 }
-                if (childpid == waitfor_pid) {
+                if (childpid == waitfor_pid /* "wait PID" */
+#if ENABLE_HUSH_BASH_COMPAT
+                 || -1 == waitfor_pid /* "wait -n" (wait for any one child) */
+#endif
+                ) {
                         debug_printf_exec("childpid==waitfor_pid:%d status:0x%08x\n", childpid, status);
                         rcode = WEXITSTATUS(status);
                         if (WIFSIGNALED(status))
@@ -11471,6 +11475,12 @@ static int wait_for_child_or_signal(struct pipe *waitfor_pipe, pid_t waitfor_pid
                         ret--;
                         if (ret < 0) /* if ECHILD, may need to fix "ret" */
                                 ret = 0;
+#if ENABLE_HUSH_BASH_COMPAT
+                        if (waitfor_pid == -1 && errno == ECHILD) {
+                                /* exitcode of "wait -n" with no children is 127, not 0 */
+                                ret = 127;
+                        }
+#endif
                         sigprocmask(SIG_SETMASK, &oldset, NULL);
                         break;
                 }
@@ -11499,6 +11509,12 @@ static int FAST_FUNC builtin_wait(char **argv)
         int status;
 
         argv = skip_dash_dash(argv);
+#if ENABLE_HUSH_BASH_COMPAT
+        if (argv[0] && !argv[1] && strcmp(argv[0], "-n") == 0) {
+                /* wait -n */
+                return wait_for_child_or_signal(NULL, -1 /*(no job, wait for one child)*/);
+        }
+#endif
         if (argv[0] == NULL) {
                 /* Don't care about wait results */
                 /* Note 1: must wait until there are no more children */