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https://github.com/sheumann/hush.git
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ash: finally installed it as /bin/sh on my machine.
some breakage noticed, the most dire is mishandled ^C. fixing it. function old new delta blocking_wait_with_raise_on_sig - 40 +40 waitforjob 85 100 +15 setsignal 280 278 -2 evalvar 1376 1374 -2 waitcmd 186 182 -4 dowait 350 316 -34 redirect 1231 1185 -46 ------------------------------------------------------------------------------ (add/remove: 1/0 grow/shrink: 1/5 up/down: 55/-88) Total: -33 bytes
This commit is contained in:
Denis Vlasenko
parent
0c68a874e7
commit
f8535ccd65
198
shell/ash.c
198
shell/ash.c
@ -201,14 +201,13 @@ struct globals_misc {
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/*
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* Sigmode records the current value of the signal handlers for the various
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* modes. A value of zero means that the current handler is not known.
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* S_HARD_IGN indicates that the signal was ignored on entry to the shell,
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* S_HARD_IGN indicates that the signal was ignored on entry to the shell.
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*/
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char sigmode[NSIG - 1];
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#define S_DFL 1 /* default signal handling (SIG_DFL) */
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#define S_CATCH 2 /* signal is caught */
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#define S_IGN 3 /* signal is ignored (SIG_IGN) */
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#define S_DFL 1 /* default signal handling (SIG_DFL) */
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#define S_CATCH 2 /* signal is caught */
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#define S_IGN 3 /* signal is ignored (SIG_IGN) */
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#define S_HARD_IGN 4 /* signal is ignored permenantly */
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#define S_RESET 5 /* temporary - to reset a hard ignored sig */
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/* indicates specified signal received */
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char gotsig[NSIG - 1]; /* offset by 1: "signal" 0 is meaningless */
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@ -368,7 +367,7 @@ force_int_on(void)
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} while (0)
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/*
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* Ignore a signal. Only one usage site - in forkchild()
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* Ignore a signal. Avoids unnecessary system calls.
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*/
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static void
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ignoresig(int signo)
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@ -3295,81 +3294,90 @@ static void setjobctl(int);
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static void
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setsignal(int signo)
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{
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int action;
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char *t, tsig;
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char *t;
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char cur_act, new_act;
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struct sigaction act;
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t = trap[signo];
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action = S_IGN;
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if (t == NULL)
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action = S_DFL;
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else if (*t != '\0')
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action = S_CATCH;
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if (rootshell && action == S_DFL) {
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new_act = S_DFL;
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if (t != NULL) { /* trap for this sig is set */
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new_act = S_CATCH;
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if (t[0] == '\0') /* trap is "": ignore this sig */
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new_act = S_IGN;
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}
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if (rootshell && new_act == S_DFL) {
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switch (signo) {
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case SIGINT:
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if (iflag || minusc || sflag == 0)
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action = S_CATCH;
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new_act = S_CATCH;
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break;
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case SIGQUIT:
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#if DEBUG
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if (debug)
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break;
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#endif
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/* FALLTHROUGH */
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/* man bash:
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* "In all cases, bash ignores SIGQUIT. Non-builtin
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* commands run by bash have signal handlers
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* set to the values inherited by the shell
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* from its parent". */
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new_act = S_IGN;
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break;
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case SIGTERM:
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if (iflag)
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action = S_IGN;
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new_act = S_IGN;
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break;
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#if JOBS
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case SIGTSTP:
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case SIGTTOU:
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if (mflag)
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action = S_IGN;
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new_act = S_IGN;
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break;
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#endif
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}
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}
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//TODO: if !rootshell, we reset SIGQUIT to DFL,
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//whereas we have to restore it to what shell got on entry
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//from the parent. See comment above
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t = &sigmode[signo - 1];
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tsig = *t;
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if (tsig == 0) {
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/*
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* current setting unknown
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*/
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if (sigaction(signo, NULL, &act) == -1) {
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/*
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* Pretend it worked; maybe we should give a warning
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* here, but other shells don't. We don't alter
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* sigmode, so that we retry every time.
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*/
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cur_act = *t;
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if (cur_act == 0) {
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/* current setting is not yet known */
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if (sigaction(signo, NULL, &act)) {
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/* pretend it worked; maybe we should give a warning,
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* but other shells don't. We don't alter sigmode,
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* so we retry every time.
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* btw, in Linux it never fails. --vda */
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return;
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}
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tsig = S_RESET; /* force to be set */
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if (act.sa_handler == SIG_IGN) {
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tsig = S_HARD_IGN;
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cur_act = S_HARD_IGN;
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if (mflag
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&& (signo == SIGTSTP || signo == SIGTTIN || signo == SIGTTOU)
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) {
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tsig = S_IGN; /* don't hard ignore these */
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cur_act = S_IGN; /* don't hard ignore these */
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}
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}
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}
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if (tsig == S_HARD_IGN || tsig == action)
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if (cur_act == S_HARD_IGN || cur_act == new_act)
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return;
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act.sa_handler = SIG_DFL;
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switch (action) {
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switch (new_act) {
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case S_CATCH:
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act.sa_handler = onsig;
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act.sa_flags = 0; /* matters only if !DFL and !IGN */
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sigfillset(&act.sa_mask); /* ditto */
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break;
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case S_IGN:
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act.sa_handler = SIG_IGN;
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break;
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}
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*t = action;
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act.sa_flags = 0;
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sigfillset(&act.sa_mask);
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sigaction_set(signo, &act);
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*t = new_act;
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}
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/* mode flags for set_curjob */
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@ -3790,15 +3798,9 @@ dowait(int wait_flags, struct job *job)
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pid = waitpid(-1, &status,
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(doing_jobctl ? (wait_flags | WUNTRACED) : wait_flags));
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TRACE(("wait returns pid=%d, status=0x%x\n", pid, status));
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if (pid <= 0) {
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/* If we were doing blocking wait and (probably) got EINTR,
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* check for pending sigs received while waiting.
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* (NB: can be moved into callers if needed) */
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if (wait_flags == DOWAIT_BLOCK && pendingsig)
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raise_exception(EXSIG);
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if (pid <= 0)
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return pid;
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}
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INT_OFF;
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thisjob = NULL;
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for (jp = curjob; jp; jp = jp->prev_job) {
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@ -3870,6 +3872,15 @@ dowait(int wait_flags, struct job *job)
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return pid;
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}
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static int
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blocking_wait_with_raise_on_sig(struct job *job)
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{
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pid_t pid = dowait(DOWAIT_BLOCK, job);
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if (pid <= 0 && pendingsig)
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raise_exception(EXSIG);
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return pid;
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}
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#if JOBS
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static void
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showjob(FILE *out, struct job *jp, int mode)
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@ -3949,7 +3960,7 @@ showjobs(FILE *out, int mode)
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TRACE(("showjobs(%x) called\n", mode));
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/* If not even one job changed, there is nothing to do */
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/* Handle all finished jobs */
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while (dowait(DOWAIT_NONBLOCK, NULL) > 0)
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continue;
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@ -4041,7 +4052,14 @@ waitcmd(int argc UNUSED_PARAM, char **argv)
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jp->waited = 1;
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jp = jp->prev_job;
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}
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dowait(DOWAIT_BLOCK, NULL);
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/* man bash:
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* "When bash is waiting for an asynchronous command via
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* the wait builtin, the reception of a signal for which a trap
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* has been set will cause the wait builtin to return immediately
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* with an exit status greater than 128, immediately after which
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* the trap is executed."
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* Do we do it that way? */
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blocking_wait_with_raise_on_sig(NULL);
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}
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}
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@ -4061,11 +4079,10 @@ waitcmd(int argc UNUSED_PARAM, char **argv)
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job = getjob(*argv, 0);
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/* loop until process terminated or stopped */
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while (job->state == JOBRUNNING)
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dowait(DOWAIT_BLOCK, NULL);
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blocking_wait_with_raise_on_sig(NULL);
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job->waited = 1;
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retval = getstatus(job);
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repeat:
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;
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repeat: ;
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} while (*++argv);
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ret:
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@ -4492,6 +4509,10 @@ forkchild(struct job *jp, /*union node *n,*/ int mode)
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oldlvl = shlvl;
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shlvl++;
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/* man bash: "Non-builtin commands run by bash have signal handlers
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* set to the values inherited by the shell from its parent".
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* Do we do it correctly? */
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closescript();
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clear_traps();
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#if JOBS
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@ -4504,8 +4525,8 @@ forkchild(struct job *jp, /*union node *n,*/ int mode)
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pgrp = getpid();
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else
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pgrp = jp->ps[0].pid;
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/* This can fail because we are doing it in the parent also */
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(void)setpgid(0, pgrp);
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/* this can fail because we are doing it in the parent also */
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setpgid(0, pgrp);
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if (mode == FORK_FG)
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xtcsetpgrp(ttyfd, pgrp);
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setsignal(SIGTSTP);
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@ -4513,6 +4534,8 @@ forkchild(struct job *jp, /*union node *n,*/ int mode)
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} else
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#endif
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if (mode == FORK_BG) {
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/* man bash: "When job control is not in effect,
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* asynchronous commands ignore SIGINT and SIGQUIT" */
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ignoresig(SIGINT);
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ignoresig(SIGQUIT);
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if (jp->nprocs == 0) {
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@ -4521,10 +4544,18 @@ forkchild(struct job *jp, /*union node *n,*/ int mode)
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ash_msg_and_raise_error("can't open %s", bb_dev_null);
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}
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}
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if (!oldlvl && iflag) {
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setsignal(SIGINT);
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if (!oldlvl) {
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if (iflag) { /* why if iflag only? */
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setsignal(SIGINT);
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setsignal(SIGTERM);
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}
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/* man bash:
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* "In all cases, bash ignores SIGQUIT. Non-builtin
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* commands run by bash have signal handlers
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* set to the values inherited by the shell
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* from its parent".
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* Take care of the second rule: */
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setsignal(SIGQUIT);
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setsignal(SIGTERM);
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}
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for (jp = curjob; jp; jp = jp->prev_job)
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freejob(jp);
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@ -4596,12 +4627,12 @@ forkshell(struct job *jp, union node *n, int mode)
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/*
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* Wait for job to finish.
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*
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* Under job control we have the problem that while a child process is
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* running interrupts generated by the user are sent to the child but not
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* to the shell. This means that an infinite loop started by an inter-
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* active user may be hard to kill. With job control turned off, an
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* interactive user may place an interactive program inside a loop. If
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* the interactive program catches interrupts, the user doesn't want
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* Under job control we have the problem that while a child process
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* is running interrupts generated by the user are sent to the child
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* but not to the shell. This means that an infinite loop started by
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* an interactive user may be hard to kill. With job control turned off,
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* an interactive user may place an interactive program inside a loop.
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* If the interactive program catches interrupts, the user doesn't want
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* these interrupts to also abort the loop. The approach we take here
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* is to have the shell ignore interrupt signals while waiting for a
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* foreground process to terminate, and then send itself an interrupt
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@ -4619,9 +4650,44 @@ waitforjob(struct job *jp)
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int st;
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TRACE(("waitforjob(%%%d) called\n", jobno(jp)));
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INT_OFF;
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while (jp->state == JOBRUNNING) {
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/* In non-interactive shells, we _can_ get
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* a keyboard signal here and be EINTRed,
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* but we just loop back, waiting for command to complete.
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*
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* man bash:
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* "If bash is waiting for a command to complete and receives
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* a signal for which a trap has been set, the trap
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* will not be executed until the command completes."
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*
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* Reality is that even if trap is not set, bash
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* will not act on the signal until command completes.
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* Try this. sleep5intoff.c:
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* #include <signal.h>
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* #include <unistd.h>
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* int main() {
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* sigset_t set;
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* sigemptyset(&set);
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* sigaddset(&set, SIGINT);
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* sigaddset(&set, SIGQUIT);
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* sigprocmask(SIG_BLOCK, &set, NULL);
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* sleep(5);
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* return 0;
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* }
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* $ bash -c './sleep5intoff; echo hi'
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* ^C^C^C^C <--- pressing ^C once a second
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* $ _
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* TODO: we do not execute "echo hi" as bash does:
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* $ bash -c './sleep5intoff; echo hi'
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* ^\^\^\^\hi <--- pressing ^\ (SIGQUIT)
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* $ _
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*/
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dowait(DOWAIT_BLOCK, jp);
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}
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INT_ON;
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st = getstatus(jp);
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#if JOBS
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if (jp->jobctl) {
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@ -4757,12 +4823,10 @@ openhere(union node *redir)
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if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) {
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/* child */
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close(pip[0]);
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signal(SIGINT, SIG_IGN);
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signal(SIGQUIT, SIG_IGN);
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signal(SIGHUP, SIG_IGN);
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#ifdef SIGTSTP
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signal(SIGTSTP, SIG_IGN);
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#endif
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ignoresig(SIGINT); //signal(SIGINT, SIG_IGN);
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ignoresig(SIGQUIT); //signal(SIGQUIT, SIG_IGN);
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ignoresig(SIGHUP); //signal(SIGHUP, SIG_IGN);
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ignoresig(SIGTSTP); //signal(SIGTSTP, SIG_IGN);
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signal(SIGPIPE, SIG_DFL);
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if (redir->type == NHERE)
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full_write(pip[1], redir->nhere.doc->narg.text, len);
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