hush: add ctrl-Z handling for nofork'ed case

diff --git a/coreutils/sleep.c b/coreutils/sleep.c
index 592005b..b758de3 100644 (file)
--- a/coreutils/sleep.c
+++ b/coreutils/sleep.c
@@ -61,6 +61,8 @@ int sleep_main(int argc, char **argv)
 #endif /* FEATURE_FANCY_SLEEP */
 
        if (sleep(duration)) {
+//for hush debugging:
+sleep(1);
                bb_perror_nomsg_and_die();
        }
 

diff --git a/shell/hush.c b/shell/hush.c
index e2ce367..c87f3b5 100644 (file)
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -431,6 +431,56 @@ static const struct built_in_command bltins[] = {
        { NULL, NULL, NULL }
 };
 
+/* move to libbb? */
+static void signal_SA_RESTART(int sig, void (*handler)(int))
+{
+       struct sigaction sa;
+       sa.sa_handler = handler;
+       sa.sa_flags = SA_RESTART;
+       sigemptyset(&sa.sa_mask);
+       sigaction(sig, &sa, NULL);
+}
+
+static sigjmp_buf nofork_jb;
+static smallint nofork_flag;
+static struct pipe *nofork_pipe;
+
+static void handler_ctrl_z(int sig)
+{
+       pid_t pid;
+
+       fprintf(stderr, "got tty sig %d\n", sig);
+       if (!nofork_flag)
+               return;
+       pid = fork();
+       if (pid < 0) /* can't fork. Pretend there were no Ctrl-Z */
+               return;
+       fprintf(stderr, "bg'ing nofork\n");
+       nofork_flag = 0;
+       nofork_pipe->running_progs = 1;
+       nofork_pipe->stopped_progs = 0;
+       if (!pid) { /* child */
+               fprintf(stderr, "setting pgrp for child\n");
+               setpgrp();
+               signal(sig, SIG_DFL); /* make child do default action (stop) */
+               raise(sig); /* resend TSTP so that child will be stopped */
+               fprintf(stderr, "returning to child\n");
+               /* return to nofork, it will eventually exit now,
+                * not return back to shell */
+               return;
+       }
+       /* parent */
+       /* finish filling up pipe info */
+       nofork_pipe->pgrp = pid; /* child is in its own pgrp */
+       nofork_pipe->progs[0].pid = pid;
+       nofork_pipe->running_progs = 1;
+       nofork_pipe->stopped_progs = 0;
+       /* parent needs to longjmp out of running nofork.
+        * we will "return" exitcode 0, with child put in background */
+// as usual we can have all kinds of nasty problems with leaked malloc data here
+       siglongjmp(nofork_jb, 1);
+}
+
 /* Restores tty foreground process group, and exits.
  * May be called as signal handler for fatal signal
  * (will faithfully resend signal to itself, producing correct exit state)
@@ -1535,14 +1585,32 @@ static int run_pipe_real(struct pipe *pi)
                }
 #if ENABLE_FEATURE_SH_STANDALONE
                {
-// FIXME: applet runs like part of shell - for example, it ignores
-// SIGINT! Try to Ctrl-C out of "rm -i"... doesn't work
                        const struct bb_applet *a = find_applet_by_name(argv[i]);
                        if (a && a->nofork) {
                                setup_redirects(child, squirrel);
-                               rcode = run_nofork_applet(a, argv + i);
-                               restore_redirects(squirrel);
-                               return rcode;
+                               if (sigsetjmp(nofork_jb, 1) == 0) {
+// enable ctrl_z here, not globally?
+                                       nofork_flag = 1;
+                                       /* TSTP handler will store pid there etc */
+                                       nofork_pipe = pi;
+                                       rcode = run_nofork_applet(a, argv + i);
+                                       if (--nofork_flag != 0)
+                                               /* Ctrl-Z! forked, we are child */
+                                               exit(rcode);
+                                       restore_redirects(squirrel);
+                                       return rcode;
+                               } else {
+                                       fprintf(stderr, "Exiting nofork early\n");
+                                       /* Ctrl-Z, forked, we are parent.
+                                        * Sighandler has longjmped us here */
+//problem: run_nofork_applet did not do the
+// "restore" trick and globals are trashed:
+// for one, applet_name is not "hush" :)
+// need to split run_nofork_applet into setup/run/restore...
+                                       restore_redirects(squirrel);
+                                       insert_bg_job(pi);
+                                       return 0;
+                               }
                        }
                }
 #endif
@@ -1585,7 +1653,7 @@ static int run_pipe_real(struct pipe *pi)
                                /* Don't do pgrp restore anymore on fatal signals */
                                set_fatal_sighandler(SIG_DFL);
                        }
-
+                       // in non-interactive case fatal sigs are already SIG_DFL
                        close_all();
                        if (nextin != 0) {
                                dup2(nextin, 0);
@@ -2927,17 +2995,16 @@ static void setup_job_control(void)
 {
        pid_t shell_pgrp;
 
-       saved_task_pgrp = getpgrp();
+       saved_task_pgrp = shell_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.  */
-       while (1) {
-               shell_pgrp = getpgrp();
-               if (tcgetpgrp(interactive_fd) == shell_pgrp)
-                       break;
-// and this does... what? need a comment here
+       /* If we were ran as 'hush &',
+        * sleep until we are in the foreground.  */
+       while (tcgetpgrp(interactive_fd) != shell_pgrp) {
+               /* Send TTIN to ourself (will stop us) */
                kill(- shell_pgrp, SIGTTIN);
+               shell_pgrp = getpgrp();
        }
 
        /* Ignore job-control and misc signals.  */
@@ -2954,6 +3021,8 @@ static void setup_job_control(void)
 
        /* Grab control of the terminal.  */
        tcsetpgrp(interactive_fd, shell_pgrp);
+
+       signal_SA_RESTART(SIGTSTP, handler_ctrl_z);
 }
 
 int hush_main(int argc, char **argv);