hush: fix more backgrounding bugs. Plenty of them remains still.

2 files changed, 29 insertions, 11 deletions

diff --git a/shell/README b/shell/README
index bcd84dcad..b78d651a5 100644
--- a/shell/README
+++ b/shell/README
@@ -1,6 +1,12 @@
 Various bits of what is known about busybox shells, in no particular order.
 
-2007-04-22
+2007-04-21
+hush: fixed non-backgrounding of "sleep 1 &" and totally broken
+"sleep 1 | sleep 2 &". Noticed a bug where successive jobs
+get numbers 1,2,3 even when job #1 has exited before job# 2 is started.
+(bash reuses #1 in this case)
+
+2007-04-21
 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".
diff --git a/shell/hush.c b/shell/hush.c
index db93f8dcb..046e098d9 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -384,6 +384,7 @@ static int parse_string_outer(const char *s, int flag);
 static int parse_file_outer(FILE *f);
 /*   job management: */
 static int checkjobs(struct pipe* fg_pipe);
+static int checkjobs_and_fg_shell(struct pipe* fg_pipe);
 static void insert_bg_job(struct pipe *pi);
 static void remove_bg_job(struct pipe *pi);
 /*     local variable support */
@@ -648,6 +649,8 @@ static int builtin_fg_bg(struct child_prog *child)
         bb_error_msg("%s: %d: no such job", child->argv[0], jobnum);
         return EXIT_FAILURE;
  found:
+        // TODO: bash prints a string representation
+        // of job being foregrounded (like "sleep 1 | cat")
         if (*child->argv[0] == 'f') {
                 /* Put the job into the foreground.  */
                 tcsetpgrp(interactive_fd, pi->pgrp);
@@ -658,6 +661,7 @@ static int builtin_fg_bg(struct child_prog *child)
                 pi->progs[i].is_stopped = 0;
 
         i = kill(- pi->pgrp, SIGCONT);
+        pi->stopped_progs = 0;
         if (i < 0) {
                 if (errno == ESRCH) {
                         remove_bg_job(pi);
@@ -666,7 +670,8 @@ static int builtin_fg_bg(struct child_prog *child)
                 }
         }
 
-        pi->stopped_progs = 0;
+        if (*child->argv[0] == 'f')
+                return checkjobs_and_fg_shell(pi);
         return EXIT_SUCCESS;
 }
 
@@ -1350,6 +1355,18 @@ static int checkjobs(struct pipe* fg_pipe)
         return rcode;
 }
 
+static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
+{
+        pid_t p;
+        int rcode = checkjobs(fg_pipe);
+        /* Job finished, move the shell to the foreground */
+        p = getpgid(0);
+        debug_printf("fg'ing ourself: getpgid(0)=%d\n", (int)p);
+        if (tcsetpgrp(interactive_fd, p) && errno != ENOTTY)
+                bb_perror_msg("tcsetpgrp-4a");
+        return rcode;
+}
+
 /* run_pipe_real() starts all the jobs, but doesn't wait for anything
  * to finish.  See checkjobs().
  *
@@ -1377,6 +1394,7 @@ static int run_pipe_real(struct pipe *pi)
         /* it is not always needed, but we aim to smaller code */
         int squirrel[] = { -1, -1, -1 };
         int rcode;
+        const int single_fg = (pi->num_progs == 1 && pi->followup != PIPE_BG);
 
         nextin = 0;
         pi->pgrp = -1;
@@ -1386,7 +1404,7 @@ static int run_pipe_real(struct pipe *pi)
          * pseudo_exec.  "echo foo | read bar" doesn't work on bash, either.
          */
         child = &(pi->progs[0]);
-        if (pi->num_progs == 1 && child->group && child->subshell == 0) {
+        if (single_fg && child->group && child->subshell == 0) {
                 debug_printf("non-subshell grouping\n");
                 setup_redirects(child, squirrel);
                 /* XXX could we merge code with following builtin case,
@@ -1396,7 +1414,7 @@ static int run_pipe_real(struct pipe *pi)
                 return rcode;
         }
 
-        if (pi->num_progs == 1 && pi->progs[0].argv != NULL) {
+        if (single_fg && pi->progs[0].argv != NULL) {
                 for (i = 0; is_assignment(child->argv[i]); i++)
                         continue;
                 if (i != 0 && child->argv[i] == NULL) {
@@ -1675,13 +1693,7 @@ static int run_list_real(struct pipe *pi)
                         rcode = EXIT_SUCCESS;
                 } else {
                         if (interactive_fd) {
-                                pid_t p;
-                                rcode = checkjobs(pi);
-                                /* move the shell to the foreground */
-                                p = getpgid(0);
-                                if (tcsetpgrp(interactive_fd, p) && errno != ENOTTY)
-                                        bb_perror_msg("tcsetpgrp-4");
-                                debug_printf("getpgid(0)=%d\n", (int)p);
+                                rcode = checkjobs_and_fg_shell(pi);
                         } else {
                                 rcode = checkjobs(pi);
                         }