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authorDenis Vlasenko2007-04-28 16:42:11 +0000
committerDenis Vlasenko2007-04-28 16:42:11 +0000
commita6a1785a30d6fe011eeabec3c19e154dc475b1b0 (patch)
tree2233696369eac228e4fe16caa802888d6fb0b17b /shell
parent706fdc98c3d30687d1ce359f58424c87e253017c (diff)
downloadbusybox-a6a1785a30d6fe011eeabec3c19e154dc475b1b0.zip
busybox-a6a1785a30d6fe011eeabec3c19e154dc475b1b0.tar.gz
hush: add ctrl-Z handling for nofork'ed case
Diffstat (limited to 'shell')
-rw-r--r--shell/hush.c95
1 files changed, 82 insertions, 13 deletions
diff --git a/shell/hush.c b/shell/hush.c
index e2ce367..c87f3b5 100644
--- 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);