blob: 1e2a867742ddf9c95489ec99d820798ec0de79c5 [file] [log] [blame]
/*-
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
* Copyright (c) 1997-2005
* Herbert Xu <herbert@gondor.apana.org.au>. 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.
*/
#include <signal.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.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"
#ifdef HETIO
#include "hetio.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 permenantly */
#define S_RESET 5 /* temporary - to reset a hard ignored sig */
/* trap handler commands */
static char *trap[NSIG];
/* number of non-null traps */
int trapcnt;
/* current value of signal */
char sigmode[NSIG - 1];
/* indicates specified signal received */
static char gotsig[NSIG - 1];
/* last pending signal */
volatile sig_atomic_t pendingsigs;
/* received SIGCHLD */
int gotsigchld;
#ifdef mkinit
INCLUDE "trap.h"
INIT {
sigmode[SIGCHLD - 1] = S_DFL;
setsignal(SIGCHLD);
}
#endif
/*
* The trap builtin.
*/
int
trapcmd(int argc, char **argv)
{
char *action;
char **ap;
int signo;
nextopt(nullstr);
ap = argptr;
if (!*ap) {
for (signo = 0 ; signo < NSIG ; signo++) {
if (trap[signo] != NULL) {
out1fmt(
"trap -- %s %s\n",
single_quote(trap[signo]),
signal_name(signo)
);
}
}
return 0;
}
if (!ap[1])
action = NULL;
else
action = *ap++;
while (*ap) {
if ((signo = decode_signal(*ap, 0)) < 0) {
outfmt(out2, "trap: %s: bad trap\n", *ap);
return 1;
}
INTOFF;
if (action) {
if (action[0] == '-' && action[1] == '\0')
action = NULL;
else {
if (*action)
trapcnt++;
action = savestr(action);
}
}
if (trap[signo]) {
if (*trap[signo])
trapcnt--;
ckfree(trap[signo]);
}
trap[signo] = action;
if (signo != 0)
setsignal(signo);
INTON;
ap++;
}
return 0;
}
/*
* Clear traps on a fork.
*/
void
clear_traps(void)
{
char **tp;
INTOFF;
for (tp = trap ; tp < &trap[NSIG] ; tp++) {
if (*tp && **tp) { /* trap not NULL or SIG_IGN */
ckfree(*tp);
*tp = NULL;
if (tp != &trap[0])
setsignal(tp - trap);
}
}
trapcnt = 0;
INTON;
}
/*
* Set the signal handler for the specified signal. The routine figures
* out what it should be set to.
*/
void
setsignal(int signo)
{
int action;
char *t, tsig;
struct sigaction act;
if ((t = trap[signo]) == NULL)
action = S_DFL;
else if (*t != '\0')
action = S_CATCH;
else
action = S_IGN;
if (rootshell && action == S_DFL) {
switch (signo) {
case SIGINT:
if (iflag || minusc || sflag == 0)
action = S_CATCH;
break;
case SIGQUIT:
#ifdef DEBUG
if (debug)
break;
#endif
/* FALLTHROUGH */
case SIGTERM:
if (iflag)
action = S_IGN;
break;
#if JOBS
case SIGTSTP:
case SIGTTOU:
if (mflag)
action = S_IGN;
break;
#endif
}
}
if (signo == SIGCHLD)
action = S_CATCH;
t = &sigmode[signo - 1];
tsig = *t;
if (tsig == 0) {
/*
* current setting unknown
*/
if (sigaction(signo, 0, &act) == -1) {
/*
* 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 (act.sa_handler == SIG_IGN) {
if (mflag && (signo == SIGTSTP ||
signo == SIGTTIN || signo == SIGTTOU)) {
tsig = S_IGN; /* don't hard ignore these */
} else
tsig = S_HARD_IGN;
} else {
tsig = S_RESET; /* force to be set */
}
}
if (tsig == S_HARD_IGN || tsig == action)
return;
switch (action) {
case S_CATCH:
act.sa_handler = onsig;
break;
case S_IGN:
act.sa_handler = SIG_IGN;
break;
default:
act.sa_handler = SIG_DFL;
}
*t = action;
act.sa_flags = 0;
sigfillset(&act.sa_mask);
sigaction(signo, &act, 0);
}
/*
* Ignore a signal.
*/
void
ignoresig(int signo)
{
if (sigmode[signo - 1] != S_IGN && sigmode[signo - 1] != S_HARD_IGN) {
signal(signo, SIG_IGN);
}
sigmode[signo - 1] = S_HARD_IGN;
}
/*
* Signal handler.
*/
void
onsig(int signo)
{
if (signo == SIGCHLD) {
gotsigchld = 1;
if (!trap[SIGCHLD])
return;
}
gotsig[signo - 1] = 1;
pendingsigs = signo;
if (signo == SIGINT && !trap[SIGINT]) {
if (!suppressint)
onint();
intpending = 1;
}
}
/*
* Called to execute a trap. Perhaps we should avoid entering new trap
* handlers while we are executing a trap handler.
*/
void dotrap(void)
{
char *p;
char *q;
int i;
int savestatus;
savestatus = exitstatus;
pendingsigs = 0;
barrier();
for (i = 0, q = gotsig; i < NSIG - 1; i++, q++) {
if (!*q)
continue;
*q = 0;
p = trap[i + 1];
if (!p)
continue;
evalstring(p, 0);
exitstatus = savestatus;
if (evalskip)
break;
}
}
/*
* Controls whether the shell is interactive or not.
*/
void
setinteractive(int on)
{
static int is_interactive;
if (++on == is_interactive)
return;
is_interactive = on;
setsignal(SIGINT);
setsignal(SIGQUIT);
setsignal(SIGTERM);
}
/*
* Called to exit the shell.
*/
void
exitshell(void)
{
struct jmploc loc;
char *p;
volatile int status;
#ifdef HETIO
hetio_reset_term();
#endif
status = exitstatus;
TRACE(("pid %d, exitshell(%d)\n", getpid(), status));
if (setjmp(loc.loc)) {
if (exception == EXEXIT)
status = exitstatus;
goto out;
}
handler = &loc;
if ((p = trap[0])) {
trap[0] = NULL;
evalskip = 0;
evalstring(p, 0);
}
out:
/*
* Disable job control so that whoever had the foreground before we
* started can get it back.
*/
if (likely(!setjmp(loc.loc)))
setjobctl(0);
flushall();
_exit(status);
/* NOTREACHED */
}
/*
* Decode a signal name
*/
int decode_signal(const char *string, int minsig)
{
int i;
if (is_number(string)) {
i = atoi(string);
if (i >= NSIG) {
return -1;
}
return i;
}
for ( i = minsig ; i < NSIG ; i++ ) {
if ( sys_sigabbrev[i] &&
!strcasecmp(string, sys_sigabbrev[i]) )
return i;
}
#ifdef SIGRTMIN
if ( !strncasecmp(string, "RTMIN", 5) ) {
char *ep;
if ( string[5] && string[5] != '+' )
return -1;
i = SIGRTMIN + strtol(string+5, &ep, 10);
if ( *ep || i < SIGRTMIN || i > SIGRTMAX )
return -1;
return i;
}
if ( !strncasecmp(string, "RTMAX", 5) ) {
char *ep;
if ( string[5] && string[5] != '-' )
return -1;
i = SIGRTMAX + strtol(string+5, &ep, 10);
if ( *ep || i < SIGRTMIN || i > SIGRTMAX )
return -1;
return i;
}
#endif
return -1;
}
/*
* Human-readable signal name
*/
const char *
signal_name(int sig)
{
static char buf[64];
if ( sig < 0 || sig >= NSIG ) {
return NULL;
} else if ( sys_sigabbrev[sig] ) {
return sys_sigabbrev[sig];
#ifdef SIGRTMIN
} else if ( sig >= SIGRTMIN && sig <= SIGRTMAX ) {
snprintf(buf, sizeof buf, "RTMIN+%d", sig-SIGRTMIN);
return buf;
#endif
} else {
snprintf(buf, sizeof buf, "%d", sig);
return buf;
}
}