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

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This commit is contained in:
Denis Vlasenko 2007-04-28 16:42:11 +00:00
parent 706fdc98c3
commit a6a1785a30
2 changed files with 84 additions and 13 deletions
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2
coreutils/sleep.c
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@ -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();
}

95
shell/hush.c
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@ -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);