hush: explain why "pipe; exit $?" doesn't show correct exitcode

diff --git a/shell/README b/shell/README
index 32ad67380756382ddf4298e1564ce688bfcc3280..bcd84dcadf70103b2ab8fe2f9431eb415cb6e6d7 100644 (file)
--- a/shell/README
+++ b/shell/README
@@ -1,5 +1,10 @@
 Various bits of what is known about busybox shells, in no particular order.
 
+2007-04-22
+hush: "sleep 1 | exit 3; echo $?" prints 0 because $? is substituted
+_before_ pipe gets executed!! run_list_real() already has "pipe;echo"
+parsed and handed to it for execution, so it sees "pipe"; "echo 0".
+
 2007-04-21
 hush: removed setsid() and made job control sort-of-sometimes-work.
 Ctrl-C in "rm -i" works now except for SH_STANDALONE case.

diff --git a/shell/hush.c b/shell/hush.c
index c4b393bce580923b77ccbdf4020a4af88280643b..db93f8dcb0c1876b50703f7d3d0b9f0ca7c71db0 100644 (file)
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -1541,7 +1541,7 @@ static int run_pipe_real(struct pipe *pi)
 
                pi->running_progs++;
 
-               /* Second and next children need to know ipd of first one */
+               /* Second and next children need to know pid of first one */
                if (pi->pgrp < 0)
                        pi->pgrp = child->pid;
 
@@ -1612,7 +1612,7 @@ static int run_list_real(struct pipe *pi)
                skip_more_in_this_rmode = RES_XXXX;
                if (rmode == RES_THEN || rmode == RES_ELSE)
                        if_code = next_if_code;
-               if (rmode == RES_THEN &&  if_code)
+               if (rmode == RES_THEN && if_code)
                        continue;
                if (rmode == RES_ELSE && !if_code)
                        continue;
@@ -2814,7 +2814,8 @@ static int parse_stream_outer(struct in_str *inp, int flag)
                ctx.type = flag;
                initialize_context(&ctx);
                update_ifs_map();
-               if (!(flag & FLAG_PARSE_SEMICOLON) || (flag & FLAG_REPARSING)) mapset(";$&|", 0);
+               if (!(flag & FLAG_PARSE_SEMICOLON) || (flag & FLAG_REPARSING))
+                        mapset(";$&|", 0);
                inp->promptmode = 1;
                rcode = parse_stream(&temp, &ctx, inp, '\n');
                if (rcode != 1 && ctx.old_flag != 0) {
@@ -2832,7 +2833,7 @@ static int parse_stream_outer(struct in_str *inp, int flag)
                        temp.nonnull = 0;
                        temp.quote = 0;
                        inp->p = NULL;
-                       free_pipe_list(ctx.list_head,0);
+                       free_pipe_list(ctx.list_head, 0);
                }
                b_free(&temp);
        } while (rcode != -1 && !(flag & FLAG_EXIT_FROM_LOOP));   /* loop on syntax errors, return on EOF */
@@ -2862,6 +2863,8 @@ static void setup_job_control(void)
 {
        pid_t shell_pgrp;
 
+       saved_task_pgrp = getpgrp();
+       debug_printf("saved_task_pgrp=%d\n", saved_task_pgrp);
        fcntl(interactive_fd, F_SETFD, FD_CLOEXEC);
 
        /* Loop until we are in the foreground.  */
@@ -2952,7 +2955,9 @@ int hush_main(int argc, char **argv)
                        opt = parse_string_outer(optarg, FLAG_PARSE_SEMICOLON);
                        goto final_return;
                case 'i':
-                       /*interactive_fd++;*/ //huh??
+                       // Well, we cannot just declare interactiveness,
+                       // we have to have some stuff (ctty, etc)
+                       /*interactive_fd++;*/
                        break;
                case 'f':
                        fake_mode++;
@@ -2980,8 +2985,6 @@ int hush_main(int argc, char **argv)
                saved_tty_pgrp = tcgetpgrp(STDIN_FILENO);
                debug_printf("saved_tty_pgrp=%d\n", saved_tty_pgrp);
                if (saved_tty_pgrp >= 0) {
-                       saved_task_pgrp = getpgrp();
-                       debug_printf("saved_task_pgrp=%d\n", saved_task_pgrp);
                        /* try to dup to high fd#, >= 255 */
                        interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
                        if (interactive_fd < 0) {
@@ -2991,17 +2994,14 @@ int hush_main(int argc, char **argv)
                                        /* give up */
                                        interactive_fd = 0;
                        }
+                       // TODO: track & disallow any attempts of user
+                       // to (inadvertently) close/redirect it
                }
        }
 
        debug_printf("\ninteractive_fd=%d\n", interactive_fd);
        if (interactive_fd) {
                /* Looks like they want an interactive shell */
-#if !ENABLE_FEATURE_SH_EXTRA_QUIET
-               printf( "\n\n%s hush - the humble shell v0.01 (testing)\n",
-                       BB_BANNER);
-               printf( "Enter 'help' for a list of built-in commands.\n\n");
-#endif
                setup_job_control();
                /* Make xfuncs do cleanup on exit */
                die_sleep = -1; /* flag */
@@ -3009,6 +3009,10 @@ int hush_main(int argc, char **argv)
                        /* xfunc has failed! die die die */
                        hush_exit(xfunc_error_retval);
                }
+#if !ENABLE_FEATURE_SH_EXTRA_QUIET
+               printf("\n\n%s hush - the humble shell v0.02\n", BB_BANNER);
+               printf("Enter 'help' for a list of built-in commands.\n\n");
+#endif
        }
 
        if (argv[optind] == NULL) {