hush: add support for "set -o pipefail"

function                                             old     new   delta
checkjobs                                            467     517     +50
builtin_set                                          259     286     +27
o_opt_strings                                          -      10     +10
hush_main                                           1011    1013      +2
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 3/0 up/down: 89/0)               Total: 89 bytes

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

3 files changed, 186 insertions, 23 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 126aaf074..50e9ce333 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -507,6 +507,7 @@ struct command {
 # define CMD_FUNCDEF 3
 #endif
 
+        smalluint cmd_exitcode;
         /* if non-NULL, this "command" is { list }, ( list ), or a compound statement */
         struct pipe *group;
 #if !BB_MMU
@@ -637,6 +638,43 @@ struct function {
 #endif
 
 
+/* set -/+o OPT support. (TODO: make it optional)
+ * bash supports the following opts:
+ * allexport       off
+ * braceexpand     on
+ * emacs           on
+ * errexit         off
+ * errtrace        off
+ * functrace       off
+ * hashall         on
+ * histexpand      off
+ * history         on
+ * ignoreeof       off
+ * interactive-comments    on
+ * keyword         off
+ * monitor         on
+ * noclobber       off
+ * noexec          off
+ * noglob          off
+ * nolog           off
+ * notify          off
+ * nounset         off
+ * onecmd          off
+ * physical        off
+ * pipefail        off
+ * posix           off
+ * privileged      off
+ * verbose         off
+ * vi              off
+ * xtrace          off
+ */
+static const char o_opt_strings[] ALIGN1 = "pipefail\0";
+enum {
+        OPT_O_PIPEFAIL,
+        NUM_OPT_O
+};
+
+
 /* "Globals" within this file */
 /* Sorted roughly by size (smaller offsets == smaller code) */
 struct globals {
@@ -675,6 +713,7 @@ struct globals {
         int last_jobid;
         pid_t saved_tty_pgrp;
         struct pipe *job_list;
+        char o_opt[NUM_OPT_O];
 # define G_saved_tty_pgrp (G.saved_tty_pgrp)
 #else
 # define G_saved_tty_pgrp 0
@@ -6315,24 +6354,23 @@ static int checkjobs(struct pipe *fg_pipe)
                                 if (fg_pipe->cmds[i].pid != childpid)
                                         continue;
                                 if (dead) {
+                                        int ex;
                                         fg_pipe->cmds[i].pid = 0;
                                         fg_pipe->alive_cmds--;
-                                        if (i == fg_pipe->num_cmds - 1) {
-                                                /* last process gives overall exitstatus */
-                                                rcode = WEXITSTATUS(status);
-                                                /* bash prints killer signal's name for *last*
-                                                 * process in pipe (prints just newline for SIGINT).
-                                                 * Mimic this. Example: "sleep 5" + (^\ or kill -QUIT)
-                                                 */
-                                                if (WIFSIGNALED(status)) {
-                                                        int sig = WTERMSIG(status);
+                                        ex = WEXITSTATUS(status);
+                                        /* bash prints killer signal's name for *last*
+                                         * process in pipe (prints just newline for SIGINT).
+                                         * Mimic this. Example: "sleep 5" + (^\ or kill -QUIT)
+                                         */
+                                        if (WIFSIGNALED(status)) {
+                                                int sig = WTERMSIG(status);
+                                                if (i == fg_pipe->num_cmds-1)
                                                         printf("%s\n", sig == SIGINT ? "" : get_signame(sig));
-                                                        /* TODO: MIPS has 128 sigs (1..128), what if sig==128 here?
-                                                         * Maybe we need to use sig | 128? */
-                                                        rcode = sig + 128;
-                                                }
-                                                IF_HAS_KEYWORDS(if (fg_pipe->pi_inverted) rcode = !rcode;)
+                                                /* TODO: MIPS has 128 sigs (1..128), what if sig==128 here?
+                                                 * Maybe we need to use sig | 128? */
+                                                ex = sig + 128;
                                         }
+                                        fg_pipe->cmds[i].cmd_exitcode = ex;
                                 } else {
                                         fg_pipe->cmds[i].is_stopped = 1;
                                         fg_pipe->stopped_cmds++;
@@ -6341,6 +6379,15 @@ static int checkjobs(struct pipe *fg_pipe)
                                                 fg_pipe->alive_cmds, fg_pipe->stopped_cmds);
                                 if (fg_pipe->alive_cmds == fg_pipe->stopped_cmds) {
                                         /* All processes in fg pipe have exited or stopped */
+                                        i = fg_pipe->num_cmds;
+                                        while (--i >= 0) {
+                                                rcode = fg_pipe->cmds[i].cmd_exitcode;
+                                                /* usually last process gives overall exitstatus,
+                                                 * but with "set -o pipefail", last *failed* process does */
+                                                if (G.o_opt[OPT_O_PIPEFAIL] == 0 || rcode != 0)
+                                                        break;
+                                        }
+                                        IF_HAS_KEYWORDS(if (fg_pipe->pi_inverted) rcode = !rcode;)
 /* Note: *non-interactive* bash does not continue if all processes in fg pipe
  * are stopped. Testcase: "cat | cat" in a script (not on command line!)
  * and "killall -STOP cat" */
@@ -7340,13 +7387,41 @@ static void set_fatal_handlers(void)
 }
 #endif
 
-static int set_mode(const char cstate, const char mode)
+static int set_mode(int state, char mode, const char *o_opt)
 {
-        int state = (cstate == '-' ? 1 : 0);
+        int idx;
         switch (mode) {
-                case 'n': G.n_mode = state; break;
-                case 'x': IF_HUSH_MODE_X(G_x_mode = state;) break;
-                default:  return EXIT_FAILURE;
+        case 'n':
+                G.n_mode = state;
+                break;
+        case 'x':
+                IF_HUSH_MODE_X(G_x_mode = state;)
+                break;
+        case 'o':
+                if (!o_opt) {
+                        /* "set -+o" without parameter.
+                         * in bash, set -o produces this output:
+                         *  pipefail        off
+                         * and set +o:
+                         *  set +o pipefail
+                         * We always use the second form.
+                         */
+                        const char *p = o_opt_strings;
+                        idx = 0;
+                        while (*p) {
+                                printf("set %co %s\n", (G.o_opt[idx] ? '-' : '+'), p);
+                                idx++;
+                                p += strlen(p) + 1;
+                        }
+                        break;
+                }
+                idx = index_in_strings(o_opt_strings, o_opt);
+                if (idx >= 0) {
+                        G.o_opt[idx] = state;
+                        break;
+                }
+        default:
+                return EXIT_FAILURE;
         }
         return EXIT_SUCCESS;
 }
@@ -7586,7 +7661,7 @@ int hush_main(int argc, char **argv)
 #endif
                 case 'n':
                 case 'x':
-                        if (set_mode('-', opt) == 0) /* no error */
+                        if (set_mode(1, opt, NULL) == 0) /* no error */
                                 break;
                 default:
 #ifndef BB_VER
@@ -8376,15 +8451,18 @@ static int FAST_FUNC builtin_set(char **argv)
         }
 
         do {
-                if (!strcmp(arg, "--")) {
+                if (strcmp(arg, "--") == 0) {
                         ++argv;
                         goto set_argv;
                 }
                 if (arg[0] != '+' && arg[0] != '-')
                         break;
-                for (n = 1; arg[n]; ++n)
-                        if (set_mode(arg[0], arg[n]))
+                for (n = 1; arg[n]; ++n) {
+                        if (set_mode((arg[0] == '-'), arg[n], argv[1]))
                                 goto error;
+                        if (arg[n] == 'o' && argv[1])
+                                argv++;
+                }
         } while ((arg = *++argv) != NULL);
         /* Now argv[0] is 1st argument */
 
diff --git a/shell/hush_test/hush-misc/pipefail.right b/shell/hush_test/hush-misc/pipefail.right
new file mode 100644
index 000000000..5845d8939
--- /dev/null
+++ b/shell/hush_test/hush-misc/pipefail.right
@@ -0,0 +1,40 @@
+Default:
+true | true:
+0
+1
+true | false:
+1
+0
+false | true:
+0
+1
+exit 2 | exit 3 | exit 4:
+4
+0
+Pipefail on:
+true | true:
+0
+1
+true | false:
+1
+0
+false | true:
+1
+0
+exit 2 | exit 3 | exit 4:
+4
+0
+Pipefail off:
+true | true:
+0
+1
+true | false:
+1
+0
+false | true:
+0
+1
+exit 2 | exit 3 | exit 4:
+4
+0
+Done
diff --git a/shell/hush_test/hush-misc/pipefail.tests b/shell/hush_test/hush-misc/pipefail.tests
new file mode 100755
index 000000000..9df841861
--- /dev/null
+++ b/shell/hush_test/hush-misc/pipefail.tests
@@ -0,0 +1,45 @@
+echo Default:
+echo "true | true:"
+  true | true; echo $?
+! true | true; echo $?
+echo "true | false:"
+  true | false; echo $?
+! true | false; echo $?
+echo "false | true:"
+  false | true; echo $?
+! false | true; echo $?
+echo "exit 2 | exit 3 | exit 4:"
+  exit 2 | exit 3 | exit 4; echo $?
+! exit 2 | exit 3 | exit 4; echo $?
+
+echo Pipefail on:
+set -o pipefail
+echo "true | true:"
+  true | true; echo $?
+! true | true; echo $?
+echo "true | false:"
+  true | false; echo $?
+! true | false; echo $?
+echo "false | true:"
+  false | true; echo $?
+! false | true; echo $?
+echo "exit 2 | exit 3 | exit 4:"
+  exit 2 | exit 3 | exit 4; echo $?
+! exit 2 | exit 3 | exit 4; echo $?
+
+echo Pipefail off:
+set +o pipefail
+echo "true | true:"
+  true | true; echo $?
+! true | true; echo $?
+echo "true | false:"
+  true | false; echo $?
+! true | false; echo $?
+echo "false | true:"
+  false | true; echo $?
+! false | true; echo $?
+echo "exit 2 | exit 3 | exit 4:"
+  exit 2 | exit 3 | exit 4; echo $?
+! exit 2 | exit 3 | exit 4; echo $?
+
+echo Done