mirror of
https://github.com/sheumann/hush.git
synced 2024-06-10 13:29:37 +00:00
hush: do not reset sighaldlers after fork - instead, prevent them from doing any harm
if they will be called. saves many sigaction calls on every fork. function old new delta hush_main 887 971 +84 sigexit 54 65 +11 run_list 2006 2001 -5 maybe_set_sighandler 76 50 -26 set_fatal_sighandler 186 - -186 ------------------------------------------------------------------------------ (add/remove: 0/1 grow/shrink: 2/2 up/down: 95/-217) Total: -122 bytes
This commit is contained in:
Denis Vlasenko
parent
d5762932fb
commit
abedaac842
219
shell/hush.c
219
shell/hush.c
|
|
@ -493,8 +493,6 @@ struct globals {
|
|||
char **traps; /* char *traps[NSIG] */
|
||||
/* which signals have non-DFL handler (even with no traps set)? */
|
||||
unsigned non_DFL_mask;
|
||||
/* which signals are known to be IGNed on entry to shell? */
|
||||
unsigned IGN_mask;
|
||||
sigset_t blocked_set;
|
||||
sigset_t inherited_set;
|
||||
};
|
||||
|
|
@ -895,128 +893,8 @@ static void check_and_run_traps(void)
|
|||
}
|
||||
}
|
||||
|
||||
/* The stuff below needs to be migrated to "Special action" above */
|
||||
|
||||
/////* Signals are grouped, we handle them in batches */
|
||||
////static void set_misc_sighandler(void (*handler)(int))
|
||||
////{
|
||||
//// bb_signals(0
|
||||
//// + (1 << SIGINT)
|
||||
//// + (1 << SIGQUIT)
|
||||
//// + (1 << SIGTERM)
|
||||
//// , handler);
|
||||
////}
|
||||
|
||||
#if ENABLE_HUSH_JOB
|
||||
|
||||
/* helper */
|
||||
static unsigned maybe_set_sighandler(int sig, void (*handler)(int))
|
||||
{
|
||||
/* non_DFL_mask'ed signals are, well, masked,
|
||||
* no need to set handler for them.
|
||||
* IGN_mask'ed signals were found to be IGN on entry,
|
||||
* do not change that -> no need to set handler for them either
|
||||
*/
|
||||
unsigned ign = ((G.IGN_mask|G.non_DFL_mask) >> sig) & 1;
|
||||
if (!ign) {
|
||||
handler = signal(sig, handler);
|
||||
ign = (handler == SIG_IGN);
|
||||
if (ign) /* restore back to IGN! */
|
||||
signal(sig, handler);
|
||||
}
|
||||
return ign << sig; /* pass back knowledge about SIG_IGN */
|
||||
}
|
||||
/* Used only to set handler to restore pgrp on exit, and to reset it to DFL */
|
||||
static void set_fatal_sighandler(void (*handler)(int))
|
||||
{
|
||||
unsigned mask = 0;
|
||||
|
||||
if (HUSH_DEBUG) {
|
||||
mask |= maybe_set_sighandler(SIGILL , handler);
|
||||
mask |= maybe_set_sighandler(SIGFPE , handler);
|
||||
mask |= maybe_set_sighandler(SIGBUS , handler);
|
||||
mask |= maybe_set_sighandler(SIGSEGV, handler);
|
||||
mask |= maybe_set_sighandler(SIGTRAP, handler);
|
||||
} /* else: hush is perfect. what SEGV? */
|
||||
|
||||
mask |= maybe_set_sighandler(SIGABRT, handler);
|
||||
|
||||
/* bash 3.2 seems to handle these just like 'fatal' ones */
|
||||
mask |= maybe_set_sighandler(SIGPIPE, handler);
|
||||
mask |= maybe_set_sighandler(SIGALRM, handler);
|
||||
mask |= maybe_set_sighandler(SIGHUP , handler);
|
||||
|
||||
/* if we aren't interactive... but in this case
|
||||
* we never want to restore pgrp on exit, and this fn is not called */
|
||||
/*mask |= maybe_set_sighandler(SIGTERM, handler); */
|
||||
/*mask |= maybe_set_sighandler(SIGINT , handler); */
|
||||
|
||||
G.IGN_mask = mask;
|
||||
}
|
||||
/* Used only to suppress ^Z in `cmd` */
|
||||
static void IGN_jobctrl_signals(void)
|
||||
{
|
||||
bb_signals(0
|
||||
+ (1 << SIGTSTP)
|
||||
+ (1 << SIGTTIN)
|
||||
+ (1 << SIGTTOU)
|
||||
, SIG_IGN);
|
||||
}
|
||||
/* SIGCHLD is special and handled separately */
|
||||
|
||||
////static void set_every_sighandler(void (*handler)(int))
|
||||
////{
|
||||
//// set_fatal_sighandler(handler);
|
||||
//// set_jobctrl_sighandler(handler);
|
||||
//// set_misc_sighandler(handler);
|
||||
//// signal(SIGCHLD, handler);
|
||||
////}
|
||||
|
||||
////static void handler_ctrl_c(int sig UNUSED_PARAM)
|
||||
////{
|
||||
//// debug_printf_jobs("got sig %d\n", sig);
|
||||
////// as usual we can have all kinds of nasty problems with leaked malloc data here
|
||||
//// siglongjmp(G.toplevel_jb, 1);
|
||||
////}
|
||||
|
||||
////static void handler_ctrl_z(int sig UNUSED_PARAM)
|
||||
////{
|
||||
//// pid_t pid;
|
||||
////
|
||||
//// debug_printf_jobs("got tty sig %d in pid %d\n", sig, getpid());
|
||||
////
|
||||
//// if (!BB_MMU) {
|
||||
//// fputs("Sorry, backgrounding (CTRL+Z) of foreground scripts not supported on nommu\n", stderr);
|
||||
//// return;
|
||||
//// }
|
||||
////
|
||||
//// pid = fork();
|
||||
//// if (pid < 0) /* can't fork. Pretend there was no ctrl-Z */
|
||||
//// return;
|
||||
//// G.ctrl_z_flag = 1;
|
||||
//// if (!pid) { /* child */
|
||||
//// if (ENABLE_HUSH_JOB)
|
||||
//// die_sleep = 0; /* let nofork's xfuncs die */
|
||||
//// bb_setpgrp();
|
||||
//// debug_printf_jobs("set pgrp for child %d ok\n", getpid());
|
||||
//////// set_every_sighandler(SIG_DFL);
|
||||
//// raise(SIGTSTP); /* resend TSTP so that child will be stopped */
|
||||
//// debug_printf_jobs("returning in child\n");
|
||||
//// /* return to nofork, it will eventually exit now,
|
||||
//// * not return back to shell */
|
||||
//// return;
|
||||
//// }
|
||||
//// /* parent */
|
||||
//// /* finish filling up pipe info */
|
||||
//// G.toplevel_list->pgrp = pid; /* child is in its own pgrp */
|
||||
//// G.toplevel_list->cmds[0].pid = pid;
|
||||
//// /* 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
|
||||
//// debug_printf_jobs("siglongjmp in parent\n");
|
||||
//// siglongjmp(G.toplevel_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)
|
||||
|
|
@ -1029,7 +907,9 @@ static void sigexit(int sig)
|
|||
sigprocmask_allsigs(SIG_BLOCK);
|
||||
|
||||
#if ENABLE_HUSH_INTERACTIVE
|
||||
if (G.interactive_fd)
|
||||
/* Careful: we can end up here after [v]fork. Do not restore
|
||||
* tty pgrp, only top-level shell process does that */
|
||||
if (G.interactive_fd && getpid() == G.root_pid)
|
||||
tcsetpgrp(G.interactive_fd, G.saved_tty_pgrp);
|
||||
#endif
|
||||
|
||||
|
|
@ -1040,10 +920,56 @@ static void sigexit(int sig)
|
|||
kill_myself_with_sig(sig); /* does not return */
|
||||
}
|
||||
|
||||
/* helper */
|
||||
static void maybe_set_sighandler(int sig)
|
||||
{
|
||||
void (*handler)(int);
|
||||
/* non_DFL_mask'ed signals are, well, masked,
|
||||
* no need to set handler for them.
|
||||
*/
|
||||
if (!((G.non_DFL_mask >> sig) & 1)) {
|
||||
handler = signal(sig, sigexit);
|
||||
if (handler == SIG_IGN) /* restore back to IGN! */
|
||||
signal(sig, handler);
|
||||
}
|
||||
}
|
||||
/* Used only to set handler to restore pgrp on exit, and to reset it to DFL */
|
||||
static void set_fatal_signals_to_sigexit(void)
|
||||
{
|
||||
if (HUSH_DEBUG) {
|
||||
maybe_set_sighandler(SIGILL );
|
||||
maybe_set_sighandler(SIGFPE );
|
||||
maybe_set_sighandler(SIGBUS );
|
||||
maybe_set_sighandler(SIGSEGV);
|
||||
maybe_set_sighandler(SIGTRAP);
|
||||
} /* else: hush is perfect. what SEGV? */
|
||||
|
||||
maybe_set_sighandler(SIGABRT);
|
||||
|
||||
/* bash 3.2 seems to handle these just like 'fatal' ones */
|
||||
maybe_set_sighandler(SIGPIPE);
|
||||
maybe_set_sighandler(SIGALRM);
|
||||
maybe_set_sighandler(SIGHUP );
|
||||
|
||||
/* if we aren't interactive... but in this case
|
||||
* we never want to restore pgrp on exit, and this fn is not called */
|
||||
/*maybe_set_sighandler(SIGTERM);*/
|
||||
/*maybe_set_sighandler(SIGINT );*/
|
||||
}
|
||||
/* Used only to suppress ^Z in `cmd` */
|
||||
static void set_jobctrl_signals_to_IGN(void)
|
||||
{
|
||||
bb_signals(0
|
||||
+ (1 << SIGTSTP)
|
||||
+ (1 << SIGTTIN)
|
||||
+ (1 << SIGTTOU)
|
||||
, SIG_IGN);
|
||||
}
|
||||
|
||||
#else /* !JOB */
|
||||
|
||||
#define set_fatal_sighandler(handler) ((void)0)
|
||||
#define IGN_jobctrl_signals(handler) ((void)0)
|
||||
#define set_fatal_signals_to_sigexit(handler) ((void)0)
|
||||
#define set_jobctrl_signals_to_IGN(handler) ((void)0)
|
||||
|
||||
#endif /* JOB */
|
||||
|
||||
|
|
@ -1057,11 +983,12 @@ static void hush_exit(int exitcode)
|
|||
free(argv[1]);
|
||||
}
|
||||
|
||||
if (ENABLE_HUSH_JOB) {
|
||||
fflush(NULL); /* flush all streams */
|
||||
sigexit(- (exitcode & 0xff));
|
||||
} else
|
||||
exit(exitcode);
|
||||
#if ENABLE_HUSH_JOB
|
||||
fflush(NULL); /* flush all streams */
|
||||
sigexit(- (exitcode & 0xff));
|
||||
#else
|
||||
exit(exitcode);
|
||||
#endif
|
||||
}
|
||||
|
||||
|
||||
|
|
@ -2641,10 +2568,6 @@ static int run_pipe(struct pipe *pi)
|
|||
* might include `cmd` runs! Do not rerun it! We *must*
|
||||
* use argv_expanded if it's non-NULL */
|
||||
|
||||
/* Disable job control signals for shell (parent) and
|
||||
* for initial child code after fork */
|
||||
//// set_jobctrl_sighandler(SIG_IGN);
|
||||
|
||||
/* Going to fork a child per each pipe member */
|
||||
pi->alive_cmds = 0;
|
||||
nextin = 0;
|
||||
|
|
@ -2677,8 +2600,6 @@ static int run_pipe(struct pipe *pi)
|
|||
* with pgid == pid_of_first_child_in_pipe */
|
||||
if (G.run_list_level == 1 && G.interactive_fd) {
|
||||
pid_t pgrp;
|
||||
/* Don't do pgrp restore anymore on fatal signals */
|
||||
set_fatal_sighandler(SIG_DFL);
|
||||
pgrp = pi->pgrp;
|
||||
if (pgrp < 0) /* true for 1st process only */
|
||||
pgrp = getpid();
|
||||
|
|
@ -2698,9 +2619,8 @@ static int run_pipe(struct pipe *pi)
|
|||
setup_redirects(command, NULL);
|
||||
|
||||
/* Restore default handlers just prior to exec */
|
||||
//// set_jobctrl_sighandler(SIG_DFL);
|
||||
//// set_misc_sighandler(SIG_DFL);
|
||||
//// signal(SIGCHLD, SIG_DFL);
|
||||
/*signal(SIGCHLD, SIG_DFL); - so far we don't have any handlers */
|
||||
|
||||
/* Stores to nommu_save list of env vars putenv'ed
|
||||
* (NOMMU, on MMU we don't need that) */
|
||||
/* cast away volatility... */
|
||||
|
|
@ -2877,7 +2797,7 @@ static int run_list(struct pipe *pi)
|
|||
* in order to return, no direct "return" statements please.
|
||||
* This helps to ensure that no memory is leaked. */
|
||||
|
||||
//TODO: needs re-thinking
|
||||
////TODO: ctrl-Z handling needs re-thinking and re-testing
|
||||
|
||||
#if ENABLE_HUSH_JOB
|
||||
/* Example of nested list: "while true; do { sleep 1 | exit 2; } done".
|
||||
|
|
@ -3674,12 +3594,11 @@ static FILE *generate_stream_from_list(struct pipe *head)
|
|||
#endif
|
||||
/* Process substitution is not considered to be usual
|
||||
* 'command execution'.
|
||||
* SUSv3 says ctrl-Z should be ignored, ctrl-C should not. */
|
||||
//// /* Not needed, we are relying on it being disabled
|
||||
//// * everywhere outside actual command execution. */
|
||||
IGN_jobctrl_signals();
|
||||
//// set_misc_sighandler(SIG_DFL);
|
||||
/* Freeing 'head' here would break NOMMU. */
|
||||
* SUSv3 says ctrl-Z should be ignored, ctrl-C should not.
|
||||
*/
|
||||
set_jobctrl_signals_to_IGN();
|
||||
|
||||
/* Note: freeing 'head' here would break NOMMU. */
|
||||
_exit(run_list(head));
|
||||
}
|
||||
close(channel[1]);
|
||||
|
|
@ -4493,13 +4412,8 @@ static void setup_job_control(void)
|
|||
shell_pgrp = getpgrp();
|
||||
}
|
||||
|
||||
/* Ignore job-control and misc signals. */
|
||||
//// set_jobctrl_sighandler(SIG_IGN);
|
||||
//// set_misc_sighandler(SIG_IGN);
|
||||
//huh? signal(SIGCHLD, SIG_IGN);
|
||||
|
||||
/* We _must_ restore tty pgrp on fatal signals */
|
||||
set_fatal_sighandler(sigexit);
|
||||
set_fatal_signals_to_sigexit();
|
||||
|
||||
/* Put ourselves in our own process group. */
|
||||
bb_setpgrp(); /* is the same as setpgid(our_pid, our_pid); */
|
||||
|
|
@ -4682,7 +4596,6 @@ int hush_main(int argc, char **argv)
|
|||
}
|
||||
if (G.interactive_fd) {
|
||||
fcntl(G.interactive_fd, F_SETFD, FD_CLOEXEC);
|
||||
//// set_misc_sighandler(SIG_IGN);
|
||||
}
|
||||
}
|
||||
init_signal_mask();
|
||||
|
|
|
|||
Loading…
Reference in New Issue
Block a user