hush: fix "(sleep 1; exit 3) & sleep 2; echo $?; wait $!; echo $?"

"wait $!" may be just a bit too late: backgrounded $! is gone.
Do not bomb out in this case.

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

diff --git a/shell/hush.c b/shell/hush.c
index 1f8a3e6079f0db3268b926fc10acc33e874211ba..7c2f157b8c5c8a9eefdd7b8f170a987b63a71873 100644 (file)
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -9529,13 +9529,22 @@ static int FAST_FUNC builtin_wait(char **argv)
                if (errno || pid <= 0) {
                        /* mimic bash message */
                        bb_error_msg("wait: '%s': not a pid or valid job spec", *argv);
-                       return EXIT_FAILURE;
+                       ret = EXIT_FAILURE;
+                       continue; /* bash checks all argv[] */
                }
                /* Do we have such child? */
                ret = waitpid(pid, &status, WNOHANG);
                if (ret < 0) {
                        /* No */
                        if (errno == ECHILD) {
+                               if (G.last_bg_pid > 0 && pid == G.last_bg_pid) {
+                                       /* "wait $!" but last bg task has already exited. Try:
+                                        * (sleep 1; exit 3) & sleep 2; echo $?; wait $!; echo $?
+                                        * In bash it prints exitcode 0, then 3.
+                                        */
+                                       ret = 0; /* FIXME */
+                                       continue;
+                               }
                                /* Example: "wait 1". mimic bash message */
                                bb_error_msg("wait: pid %d is not a child of this shell", (int)pid);
                        } else {
@@ -9543,7 +9552,9 @@ static int FAST_FUNC builtin_wait(char **argv)
                                bb_perror_msg("wait %s", *argv);
                        }
                        ret = 127;
-               } else if (ret == 0) {
+                       continue; /* bash checks all argv[] */
+               }
+               if (ret == 0) {
                        /* Yes, and it still runs */
                        ret = wait_for_child_or_signal(pid);
                } else {
@@ -9553,8 +9564,7 @@ static int FAST_FUNC builtin_wait(char **argv)
                        if (WIFSIGNALED(status))
                                ret = 128 + WTERMSIG(status);
                }
-               argv++;
-       } while (*argv);
+       } while (*++argv);
 
        return ret;
 }