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hush: fix nofork + ctrl-Z clobbering of globals
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a6a1785a30
commit
18e19f2b0d
@ -509,10 +509,20 @@ int wait_nohang(int *wstat);
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#define wait_exitcode(w) ((w) >> 8)
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#define wait_stopsig(w) ((w) >> 8)
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#define wait_stopped(w) (((w) & 127) == 127)
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/* Does NOT check that applet is NOFORK, just blindly runs it */
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int run_nofork_applet(const struct bb_applet *a, char **argv);
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/* wait4pid(spawn(argv)) + NOFORK/NOEXEC (if configured) */
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int spawn_and_wait(char **argv);
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struct nofork_save_area {
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const struct bb_applet *current_applet;
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int xfunc_error_retval;
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uint32_t option_mask32;
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int die_sleep;
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smallint saved;
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};
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void save_nofork_data(struct nofork_save_area *save);
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void restore_nofork_data(struct nofork_save_area *save);
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/* Does NOT check that applet is NOFORK, just blindly runs it */
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int run_nofork_applet(const struct bb_applet *a, char **argv);
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int run_nofork_applet_prime(struct nofork_save_area *old, const struct bb_applet *a, char **argv);
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/* Helpers for daemonization.
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*
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@ -100,16 +100,29 @@ int wait_pid(int *wstat, int pid)
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return r;
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}
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int run_nofork_applet(const struct bb_applet *a, char **argv)
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void save_nofork_data(struct nofork_save_area *save)
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{
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save->current_applet = current_applet;
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save->xfunc_error_retval = xfunc_error_retval;
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save->option_mask32 = option_mask32;
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save->die_sleep = die_sleep;
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save->saved = 1;
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}
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void restore_nofork_data(struct nofork_save_area *save)
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{
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current_applet = save->current_applet;
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xfunc_error_retval = save->xfunc_error_retval;
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option_mask32 = save->option_mask32;
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die_sleep = save->die_sleep;
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applet_name = current_applet->name;
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}
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int run_nofork_applet_prime(struct nofork_save_area *old, const struct bb_applet *a, char **argv)
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{
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int rc, argc;
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/* Save some shared globals */
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const struct bb_applet *old_a = current_applet;
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int old_x = xfunc_error_retval;
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uint32_t old_m = option_mask32;
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int old_sleep = die_sleep;
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current_applet = a;
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applet_name = a->name;
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xfunc_error_retval = EXIT_FAILURE;
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@ -138,14 +151,18 @@ int run_nofork_applet(const struct bb_applet *a, char **argv)
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}
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/* Restoring globals */
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current_applet = old_a;
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applet_name = old_a->name;
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xfunc_error_retval = old_x;
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option_mask32 = old_m;
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die_sleep = old_sleep;
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restore_nofork_data(old);
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return rc;
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}
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int run_nofork_applet(const struct bb_applet *a, char **argv)
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{
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struct nofork_save_area old;
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/* Saving globals */
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save_nofork_data(&old);
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return run_nofork_applet_prime(&old, a, argv);
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}
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int spawn_and_wait(char **argv)
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{
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int rc;
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40
shell/hush.c
40
shell/hush.c
@ -441,30 +441,28 @@ static void signal_SA_RESTART(int sig, void (*handler)(int))
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sigaction(sig, &sa, NULL);
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}
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struct nofork_save_area nofork_save;
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static sigjmp_buf nofork_jb;
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static smallint nofork_flag;
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static struct pipe *nofork_pipe;
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static void handler_ctrl_z(int sig)
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{
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pid_t pid;
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fprintf(stderr, "got tty sig %d\n", sig);
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if (!nofork_flag)
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return;
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debug_jobs_printf("got tty sig %d\n", sig);
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pid = fork();
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if (pid < 0) /* can't fork. Pretend there were no Ctrl-Z */
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return;
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fprintf(stderr, "bg'ing nofork\n");
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nofork_flag = 0;
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debug_jobs_printf("bg'ing nofork\n");
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nofork_save.saved = 0; /* flag the fact that Ctrl-Z was handled */
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nofork_pipe->running_progs = 1;
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nofork_pipe->stopped_progs = 0;
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if (!pid) { /* child */
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fprintf(stderr, "setting pgrp for child\n");
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debug_jobs_printf("setting pgrp for child\n");
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setpgrp();
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signal(sig, SIG_DFL); /* make child do default action (stop) */
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raise(sig); /* resend TSTP so that child will be stopped */
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fprintf(stderr, "returning to child\n");
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signal(SIGTSTP, SIG_DFL); /* make child do default action (stop) */
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raise(SIGTSTP); /* resend TSTP so that child will be stopped */
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debug_jobs_printf("returning to child\n");
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/* return to nofork, it will eventually exit now,
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* not return back to shell */
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return;
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@ -1588,25 +1586,23 @@ static int run_pipe_real(struct pipe *pi)
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const struct bb_applet *a = find_applet_by_name(argv[i]);
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if (a && a->nofork) {
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setup_redirects(child, squirrel);
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if (sigsetjmp(nofork_jb, 1) == 0) {
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// enable ctrl_z here, not globally?
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nofork_flag = 1;
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/* TSTP handler will store pid there etc */
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/* TSTP handler will store pid etc in pi */
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nofork_pipe = pi;
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rcode = run_nofork_applet(a, argv + i);
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if (--nofork_flag != 0)
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save_nofork_data(&nofork_save);
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if (sigsetjmp(nofork_jb, 1) == 0) {
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signal_SA_RESTART(SIGTSTP, handler_ctrl_z);
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rcode = run_nofork_applet_prime(&nofork_save, a, argv + i);
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if (--nofork_save.saved != 0)
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/* Ctrl-Z! forked, we are child */
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exit(rcode);
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restore_redirects(squirrel);
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return rcode;
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} else {
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fprintf(stderr, "Exiting nofork early\n");
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/* Ctrl-Z, forked, we are parent.
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* Sighandler has longjmped us here */
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//problem: run_nofork_applet did not do the
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// "restore" trick and globals are trashed:
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// for one, applet_name is not "hush" :)
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// need to split run_nofork_applet into setup/run/restore...
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signal(SIGTSTP, SIG_IGN);
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debug_jobs_printf("Exiting nofork early\n");
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restore_nofork_data(&nofork_save);
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restore_redirects(squirrel);
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insert_bg_job(pi);
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return 0;
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@ -3021,8 +3017,6 @@ static void setup_job_control(void)
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/* Grab control of the terminal. */
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tcsetpgrp(interactive_fd, shell_pgrp);
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signal_SA_RESTART(SIGTSTP, handler_ctrl_z);
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}
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int hush_main(int argc, char **argv);
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