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hush: fix nofork + ctrl-Z clobbering of globals

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This commit is contained in:
Denis Vlasenko 2007-04-28 16:43:18 +00:00
parent a6a1785a30
commit 18e19f2b0d
3 changed files with 58 additions and 37 deletions
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14
include/libbb.h
View File

@ -509,10 +509,20 @@ int wait_nohang(int *wstat);
#define wait_exitcode(w) ((w) >> 8)
#define wait_stopsig(w) ((w) >> 8)
#define wait_stopped(w) (((w) & 127) == 127)
/* Does NOT check that applet is NOFORK, just blindly runs it */
int run_nofork_applet(const struct bb_applet *a, char **argv);
/* wait4pid(spawn(argv)) + NOFORK/NOEXEC (if configured) */
int spawn_and_wait(char **argv);
struct nofork_save_area {
const struct bb_applet *current_applet;
int xfunc_error_retval;
uint32_t option_mask32;
int die_sleep;
smallint saved;
};
void save_nofork_data(struct nofork_save_area *save);
void restore_nofork_data(struct nofork_save_area *save);
/* Does NOT check that applet is NOFORK, just blindly runs it */
int run_nofork_applet(const struct bb_applet *a, char **argv);
int run_nofork_applet_prime(struct nofork_save_area *old, const struct bb_applet *a, char **argv);
/* Helpers for daemonization.
*

41
libbb/vfork_daemon_rexec.c
View File

@ -100,16 +100,29 @@ int wait_pid(int *wstat, int pid)
return r;
}
int run_nofork_applet(const struct bb_applet *a, char **argv)
void save_nofork_data(struct nofork_save_area *save)
{
save->current_applet = current_applet;
save->xfunc_error_retval = xfunc_error_retval;
save->option_mask32 = option_mask32;
save->die_sleep = die_sleep;
save->saved = 1;
}
void restore_nofork_data(struct nofork_save_area *save)
{
current_applet = save->current_applet;
xfunc_error_retval = save->xfunc_error_retval;
option_mask32 = save->option_mask32;
die_sleep = save->die_sleep;
applet_name = current_applet->name;
}
int run_nofork_applet_prime(struct nofork_save_area *old, const struct bb_applet *a, char **argv)
{
int rc, argc;
/* Save some shared globals */
const struct bb_applet *old_a = current_applet;
int old_x = xfunc_error_retval;
uint32_t old_m = option_mask32;
int old_sleep = die_sleep;
current_applet = a;
applet_name = a->name;
xfunc_error_retval = EXIT_FAILURE;
@ -138,14 +151,18 @@ int run_nofork_applet(const struct bb_applet *a, char **argv)
}
/* Restoring globals */
current_applet = old_a;
applet_name = old_a->name;
xfunc_error_retval = old_x;
option_mask32 = old_m;
die_sleep = old_sleep;
restore_nofork_data(old);
return rc;
}
int run_nofork_applet(const struct bb_applet *a, char **argv)
{
struct nofork_save_area old;
/* Saving globals */
save_nofork_data(&old);
return run_nofork_applet_prime(&old, a, argv);
}
int spawn_and_wait(char **argv)
{
int rc;

40
shell/hush.c
View File

@ -441,30 +441,28 @@ static void signal_SA_RESTART(int sig, void (*handler)(int))
sigaction(sig, &sa, NULL);
}
struct nofork_save_area nofork_save;
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;
debug_jobs_printf("got tty sig %d\n", sig);
pid = fork();
if (pid < 0) /* can't fork. Pretend there were no Ctrl-Z */
return;
fprintf(stderr, "bg'ing nofork\n");
nofork_flag = 0;
debug_jobs_printf("bg'ing nofork\n");
nofork_save.saved = 0; /* flag the fact that Ctrl-Z was handled */
nofork_pipe->running_progs = 1;
nofork_pipe->stopped_progs = 0;
if (!pid) { /* child */
fprintf(stderr, "setting pgrp for child\n");
debug_jobs_printf("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");
signal(SIGTSTP, SIG_DFL); /* make child do default action (stop) */
raise(SIGTSTP); /* resend TSTP so that child will be stopped */
debug_jobs_printf("returning to child\n");
/* return to nofork, it will eventually exit now,
* not return back to shell */
return;
@ -1588,25 +1586,23 @@ static int run_pipe_real(struct pipe *pi)
const struct bb_applet *a = find_applet_by_name(argv[i]);
if (a && a->nofork) {
setup_redirects(child, squirrel);
/* TSTP handler will store pid etc in pi */
nofork_pipe = pi;
save_nofork_data(&nofork_save);
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)
signal_SA_RESTART(SIGTSTP, handler_ctrl_z);
rcode = run_nofork_applet_prime(&nofork_save, a, argv + i);
if (--nofork_save.saved != 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...
signal(SIGTSTP, SIG_IGN);
debug_jobs_printf("Exiting nofork early\n");
restore_nofork_data(&nofork_save);
restore_redirects(squirrel);
insert_bg_job(pi);
return 0;
@ -3021,8 +3017,6 @@ 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);