554 lines
11 KiB
C
554 lines
11 KiB
C
/*-
|
|
* SPDX-License-Identifier: BSD-3-Clause
|
|
*
|
|
* Copyright (c) 1991, 1993
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* This code is derived from software contributed to Berkeley by
|
|
* Kenneth Almquist.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#ifndef lint
|
|
#if 0
|
|
static char sccsid[] = "@(#)trap.c 8.5 (Berkeley) 6/5/95";
|
|
#endif
|
|
#endif /* not lint */
|
|
#include <sys/cdefs.h>
|
|
#include <signal.h>
|
|
#include <unistd.h>
|
|
#include <stdlib.h>
|
|
|
|
#include "shell.h"
|
|
#include "main.h"
|
|
#include "nodes.h" /* for other headers */
|
|
#include "eval.h"
|
|
#include "jobs.h"
|
|
#include "show.h"
|
|
#include "options.h"
|
|
#include "syntax.h"
|
|
#include "output.h"
|
|
#include "memalloc.h"
|
|
#include "error.h"
|
|
#include "trap.h"
|
|
#include "mystring.h"
|
|
#include "builtins.h"
|
|
#ifndef NO_HISTORY
|
|
#include "myhistedit.h"
|
|
#endif
|
|
|
|
|
|
/*
|
|
* Sigmode records the current value of the signal handlers for the various
|
|
* modes. A value of zero means that the current handler is not known.
|
|
* S_HARD_IGN indicates that the signal was ignored on entry to the shell,
|
|
*/
|
|
|
|
#define S_DFL 1 /* default signal handling (SIG_DFL) */
|
|
#define S_CATCH 2 /* signal is caught */
|
|
#define S_IGN 3 /* signal is ignored (SIG_IGN) */
|
|
#define S_HARD_IGN 4 /* signal is ignored permanently */
|
|
#define S_RESET 5 /* temporary - to reset a hard ignored sig */
|
|
|
|
|
|
static char sigmode[NSIG]; /* current value of signal */
|
|
volatile sig_atomic_t pendingsig; /* indicates some signal received */
|
|
volatile sig_atomic_t pendingsig_waitcmd; /* indicates wait builtin should be interrupted */
|
|
static int in_dotrap; /* do we execute in a trap handler? */
|
|
static char *volatile trap[NSIG]; /* trap handler commands */
|
|
static volatile sig_atomic_t gotsig[NSIG];
|
|
/* indicates specified signal received */
|
|
static int ignore_sigchld; /* Used while handling SIGCHLD traps. */
|
|
static int last_trapsig;
|
|
|
|
static int exiting; /* exitshell() has been called */
|
|
static int exiting_exitstatus; /* value passed to exitshell() */
|
|
|
|
static int getsigaction(int, sig_t *);
|
|
|
|
|
|
/*
|
|
* Map a string to a signal number.
|
|
*
|
|
* Note: the signal number may exceed NSIG.
|
|
*/
|
|
static int
|
|
sigstring_to_signum(char *sig)
|
|
{
|
|
|
|
if (is_number(sig)) {
|
|
int signo;
|
|
|
|
signo = atoi(sig);
|
|
return ((signo >= 0 && signo < NSIG) ? signo : (-1));
|
|
} else if (strcasecmp(sig, "EXIT") == 0) {
|
|
return (0);
|
|
} else {
|
|
int n;
|
|
|
|
if (strncasecmp(sig, "SIG", 3) == 0)
|
|
sig += 3;
|
|
for (n = 1; n < sys_nsig; n++)
|
|
if (sys_signame[n] &&
|
|
strcasecmp(sys_signame[n], sig) == 0)
|
|
return (n);
|
|
}
|
|
return (-1);
|
|
}
|
|
|
|
|
|
/*
|
|
* Print a list of valid signal names.
|
|
*/
|
|
static void
|
|
printsignals(void)
|
|
{
|
|
int n, outlen;
|
|
|
|
outlen = 0;
|
|
for (n = 1; n < sys_nsig; n++) {
|
|
if (sys_signame[n]) {
|
|
out1fmt("%s", sys_signame[n]);
|
|
outlen += strlen(sys_signame[n]);
|
|
} else {
|
|
out1fmt("%d", n);
|
|
outlen += 3; /* good enough */
|
|
}
|
|
++outlen;
|
|
if (outlen > 71 || n == sys_nsig - 1) {
|
|
out1str("\n");
|
|
outlen = 0;
|
|
} else {
|
|
out1c(' ');
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* The trap builtin.
|
|
*/
|
|
int
|
|
trapcmd(int argc __unused, char **argv)
|
|
{
|
|
char *action;
|
|
int signo;
|
|
int errors = 0;
|
|
int i;
|
|
|
|
while ((i = nextopt("l")) != '\0') {
|
|
switch (i) {
|
|
case 'l':
|
|
printsignals();
|
|
return (0);
|
|
}
|
|
}
|
|
argv = argptr;
|
|
|
|
if (*argv == NULL) {
|
|
for (signo = 0 ; signo < sys_nsig ; signo++) {
|
|
if (signo < NSIG && trap[signo] != NULL) {
|
|
out1str("trap -- ");
|
|
out1qstr(trap[signo]);
|
|
if (signo == 0) {
|
|
out1str(" EXIT\n");
|
|
} else if (sys_signame[signo]) {
|
|
out1fmt(" %s\n", sys_signame[signo]);
|
|
} else {
|
|
out1fmt(" %d\n", signo);
|
|
}
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
action = NULL;
|
|
if (*argv && !is_number(*argv)) {
|
|
if (strcmp(*argv, "-") == 0)
|
|
argv++;
|
|
else {
|
|
action = *argv;
|
|
argv++;
|
|
}
|
|
}
|
|
for (; *argv; argv++) {
|
|
if ((signo = sigstring_to_signum(*argv)) == -1) {
|
|
warning("bad signal %s", *argv);
|
|
errors = 1;
|
|
continue;
|
|
}
|
|
INTOFF;
|
|
if (action)
|
|
action = savestr(action);
|
|
if (trap[signo])
|
|
ckfree(trap[signo]);
|
|
trap[signo] = action;
|
|
if (signo != 0)
|
|
setsignal(signo);
|
|
INTON;
|
|
}
|
|
return errors;
|
|
}
|
|
|
|
|
|
/*
|
|
* Clear traps on a fork.
|
|
*/
|
|
void
|
|
clear_traps(void)
|
|
{
|
|
char *volatile *tp;
|
|
|
|
for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
|
|
if (*tp && **tp) { /* trap not NULL or SIG_IGN */
|
|
INTOFF;
|
|
ckfree(*tp);
|
|
*tp = NULL;
|
|
if (tp != &trap[0])
|
|
setsignal(tp - trap);
|
|
INTON;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* Check if we have any traps enabled.
|
|
*/
|
|
int
|
|
have_traps(void)
|
|
{
|
|
char *volatile *tp;
|
|
|
|
for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
|
|
if (*tp && **tp) /* trap not NULL or SIG_IGN */
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Set the signal handler for the specified signal. The routine figures
|
|
* out what it should be set to.
|
|
*/
|
|
void
|
|
setsignal(int signo)
|
|
{
|
|
int action;
|
|
sig_t sigact = SIG_DFL;
|
|
struct sigaction sa;
|
|
char *t;
|
|
|
|
if ((t = trap[signo]) == NULL)
|
|
action = S_DFL;
|
|
else if (*t != '\0')
|
|
action = S_CATCH;
|
|
else
|
|
action = S_IGN;
|
|
if (action == S_DFL) {
|
|
switch (signo) {
|
|
case SIGINT:
|
|
action = S_CATCH;
|
|
break;
|
|
case SIGQUIT:
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
break;
|
|
#endif
|
|
action = S_CATCH;
|
|
break;
|
|
case SIGTERM:
|
|
if (rootshell && iflag)
|
|
action = S_IGN;
|
|
break;
|
|
#if JOBS
|
|
case SIGTSTP:
|
|
case SIGTTOU:
|
|
if (rootshell && mflag)
|
|
action = S_IGN;
|
|
break;
|
|
#endif
|
|
}
|
|
}
|
|
|
|
t = &sigmode[signo];
|
|
if (*t == 0) {
|
|
/*
|
|
* current setting unknown
|
|
*/
|
|
if (!getsigaction(signo, &sigact)) {
|
|
/*
|
|
* Pretend it worked; maybe we should give a warning
|
|
* here, but other shells don't. We don't alter
|
|
* sigmode, so that we retry every time.
|
|
*/
|
|
return;
|
|
}
|
|
if (sigact == SIG_IGN) {
|
|
if (mflag && (signo == SIGTSTP ||
|
|
signo == SIGTTIN || signo == SIGTTOU)) {
|
|
*t = S_IGN; /* don't hard ignore these */
|
|
} else
|
|
*t = S_HARD_IGN;
|
|
} else {
|
|
*t = S_RESET; /* force to be set */
|
|
}
|
|
}
|
|
if (*t == S_HARD_IGN || *t == action)
|
|
return;
|
|
switch (action) {
|
|
case S_DFL: sigact = SIG_DFL; break;
|
|
case S_CATCH: sigact = onsig; break;
|
|
case S_IGN: sigact = SIG_IGN; break;
|
|
}
|
|
*t = action;
|
|
sa.sa_handler = sigact;
|
|
sa.sa_flags = 0;
|
|
sigemptyset(&sa.sa_mask);
|
|
sigaction(signo, &sa, NULL);
|
|
}
|
|
|
|
|
|
/*
|
|
* Return the current setting for sig w/o changing it.
|
|
*/
|
|
static int
|
|
getsigaction(int signo, sig_t *sigact)
|
|
{
|
|
struct sigaction sa;
|
|
|
|
if (sigaction(signo, (struct sigaction *)0, &sa) == -1)
|
|
return 0;
|
|
*sigact = (sig_t) sa.sa_handler;
|
|
return 1;
|
|
}
|
|
|
|
|
|
/*
|
|
* Ignore a signal.
|
|
*/
|
|
void
|
|
ignoresig(int signo)
|
|
{
|
|
|
|
if (sigmode[signo] == 0)
|
|
setsignal(signo);
|
|
if (sigmode[signo] != S_IGN && sigmode[signo] != S_HARD_IGN) {
|
|
signal(signo, SIG_IGN);
|
|
sigmode[signo] = S_IGN;
|
|
}
|
|
}
|
|
|
|
|
|
int
|
|
issigchldtrapped(void)
|
|
{
|
|
|
|
return (trap[SIGCHLD] != NULL && *trap[SIGCHLD] != '\0');
|
|
}
|
|
|
|
|
|
/*
|
|
* Signal handler.
|
|
*/
|
|
void
|
|
onsig(int signo)
|
|
{
|
|
|
|
if (signo == SIGINT && trap[SIGINT] == NULL) {
|
|
if (suppressint)
|
|
SET_PENDING_INT;
|
|
else
|
|
onint();
|
|
return;
|
|
}
|
|
|
|
/* If we are currently in a wait builtin, prepare to break it */
|
|
if (signo == SIGINT || signo == SIGQUIT)
|
|
pendingsig_waitcmd = signo;
|
|
|
|
if (trap[signo] != NULL && trap[signo][0] != '\0' &&
|
|
(signo != SIGCHLD || !ignore_sigchld)) {
|
|
gotsig[signo] = 1;
|
|
pendingsig = signo;
|
|
pendingsig_waitcmd = signo;
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* Called to execute a trap. Perhaps we should avoid entering new trap
|
|
* handlers while we are executing a trap handler.
|
|
*/
|
|
void
|
|
dotrap(void)
|
|
{
|
|
struct stackmark smark;
|
|
int i;
|
|
int savestatus, prev_evalskip, prev_skipcount;
|
|
|
|
in_dotrap++;
|
|
for (;;) {
|
|
pendingsig = 0;
|
|
pendingsig_waitcmd = 0;
|
|
for (i = 1; i < NSIG; i++) {
|
|
if (gotsig[i]) {
|
|
gotsig[i] = 0;
|
|
if (trap[i]) {
|
|
/*
|
|
* Ignore SIGCHLD to avoid infinite
|
|
* recursion if the trap action does
|
|
* a fork.
|
|
*/
|
|
if (i == SIGCHLD)
|
|
ignore_sigchld++;
|
|
|
|
/*
|
|
* Backup current evalskip
|
|
* state and reset it before
|
|
* executing a trap, so that the
|
|
* trap is not disturbed by an
|
|
* ongoing break/continue/return
|
|
* statement.
|
|
*/
|
|
prev_evalskip = evalskip;
|
|
prev_skipcount = skipcount;
|
|
evalskip = 0;
|
|
|
|
last_trapsig = i;
|
|
savestatus = exitstatus;
|
|
setstackmark(&smark);
|
|
evalstring(stsavestr(trap[i]), 0);
|
|
popstackmark(&smark);
|
|
|
|
/*
|
|
* If such a command was not
|
|
* already in progress, allow a
|
|
* break/continue/return in the
|
|
* trap action to have an effect
|
|
* outside of it.
|
|
*/
|
|
if (evalskip == 0 ||
|
|
prev_evalskip != 0) {
|
|
evalskip = prev_evalskip;
|
|
skipcount = prev_skipcount;
|
|
exitstatus = savestatus;
|
|
}
|
|
|
|
if (i == SIGCHLD)
|
|
ignore_sigchld--;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
if (i >= NSIG)
|
|
break;
|
|
}
|
|
in_dotrap--;
|
|
}
|
|
|
|
|
|
void
|
|
trap_init(void)
|
|
{
|
|
setsignal(SIGINT);
|
|
setsignal(SIGQUIT);
|
|
}
|
|
|
|
|
|
/*
|
|
* Controls whether the shell is interactive or not based on iflag.
|
|
*/
|
|
void
|
|
setinteractive(void)
|
|
{
|
|
setsignal(SIGTERM);
|
|
}
|
|
|
|
|
|
/*
|
|
* Called to exit the shell.
|
|
*/
|
|
void
|
|
exitshell(int status)
|
|
{
|
|
TRACE(("exitshell(%d) pid=%d\n", status, getpid()));
|
|
exiting = 1;
|
|
exiting_exitstatus = status;
|
|
exitshell_savedstatus();
|
|
}
|
|
|
|
void
|
|
exitshell_savedstatus(void)
|
|
{
|
|
struct jmploc loc1, loc2;
|
|
char *p;
|
|
int sig = 0;
|
|
sigset_t sigs;
|
|
|
|
if (!exiting) {
|
|
if (in_dotrap && last_trapsig) {
|
|
sig = last_trapsig;
|
|
exiting_exitstatus = sig + 128;
|
|
} else
|
|
exiting_exitstatus = oexitstatus;
|
|
}
|
|
exitstatus = oexitstatus = exiting_exitstatus;
|
|
if (!setjmp(loc1.loc)) {
|
|
handler = &loc1;
|
|
if ((p = trap[0]) != NULL && *p != '\0') {
|
|
/*
|
|
* Reset evalskip, or the trap on EXIT could be
|
|
* interrupted if the last command was a "return".
|
|
*/
|
|
evalskip = 0;
|
|
trap[0] = NULL;
|
|
FORCEINTON;
|
|
evalstring(p, 0);
|
|
}
|
|
}
|
|
if (!setjmp(loc2.loc)) {
|
|
handler = &loc2; /* probably unnecessary */
|
|
FORCEINTON;
|
|
flushall();
|
|
#if JOBS
|
|
setjobctl(0);
|
|
#endif
|
|
#ifndef NO_HISTORY
|
|
histsave();
|
|
#endif
|
|
}
|
|
if (sig != 0 && sig != SIGSTOP && sig != SIGTSTP && sig != SIGTTIN &&
|
|
sig != SIGTTOU) {
|
|
signal(sig, SIG_DFL);
|
|
sigemptyset(&sigs);
|
|
sigaddset(&sigs, sig);
|
|
sigprocmask(SIG_UNBLOCK, &sigs, NULL);
|
|
kill(getpid(), sig);
|
|
/* If the default action is to ignore, fall back to _exit(). */
|
|
}
|
|
_exit(exiting_exitstatus);
|
|
}
|