a6a1785a3
Denis Vlasenko
2007-04-28
Subject
hush: add ctrl-Z handling for nofork'ed case
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coreutils/sleep.c+2 -0
| @@ -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(); | |
| } | |
shell/hush.c+82 -13
| @@ -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); | |