usr/dash/trap.c

/*-
 * 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 */
char *trap[NSIG];
/* current value of signal */
static char sigmode[NSIG - 1];
/* indicates specified signal received */
char gotsig[NSIG - 1];
/* last pending signal */
volatile sig_atomic_t pendingsigs;
/* do we generate EXSIG events */
int exsig;

#ifdef mkinit
INCLUDE <signal.h>
INIT {
	signal(SIGCHLD, SIG_DFL);
}
#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)
			sh_error("%s: bad trap", *ap);
		INTOFF;
		if (action) {
			if (action[0] == '-' && action[1] == '\0')
				action = NULL;
			else
				action = savestr(action);
		}
		if (trap[signo])
			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;

	for (tp = trap ; tp < &trap[NSIG] ; tp++) {
		if (*tp && **tp) {	/* trap not NULL or SIG_IGN */
			INTOFF;
			ckfree(*tp);
			*tp = NULL;
			if (tp != &trap[0])
				setsignal(tp - trap);
			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
		}
	}

	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)
{
	gotsig[signo - 1] = 1;
	pendingsigs = signo;

	if (exsig || (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.
 */

int
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, SKIPEVAL);
		exitstatus = savestatus;
		if (evalskip)
			return evalskip;
	}

	return 0;
}


/*
 * 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;
	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)
			_exit(exitstatus);
		goto out;
	}
	handler = &loc;
	if ((p = trap[0])) {
		trap[0] = NULL;
		evalstring(p, 0);
	}
	flushall();
out:
	_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;
	}
}
1	niro	532	/*-
2			* Copyright (c) 1991, 1993
3			* The Regents of the University of California. All rights reserved.
4			* Copyright (c) 1997-2005
5			* Herbert Xu <herbert@gondor.apana.org.au>. All rights reserved.
6			*
7			* This code is derived from software contributed to Berkeley by
8			* Kenneth Almquist.
9			*
10			* Redistribution and use in source and binary forms, with or without
11			* modification, are permitted provided that the following conditions
12			* are met:
13			* 1. Redistributions of source code must retain the above copyright
14			* notice, this list of conditions and the following disclaimer.
15			* 2. Redistributions in binary form must reproduce the above copyright
16			* notice, this list of conditions and the following disclaimer in the
17			* documentation and/or other materials provided with the distribution.
18			* 3. Neither the name of the University nor the names of its contributors
19			* may be used to endorse or promote products derived from this software
20			* without specific prior written permission.
21			*
22			* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23			* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24			* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25			* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26			* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27			* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28			* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29			* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30			* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31			* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32			* SUCH DAMAGE.
33			*/
34
35			#include <signal.h>
36			#include <unistd.h>
37			#include <stdlib.h>
38			#include <string.h>
39			#include <stdio.h>
40
41			#include "shell.h"
42			#include "main.h"
43			#include "nodes.h" /* for other headers */
44			#include "eval.h"
45			#include "jobs.h"
46			#include "show.h"
47			#include "options.h"
48			#include "syntax.h"
49			#include "output.h"
50			#include "memalloc.h"
51			#include "error.h"
52			#include "trap.h"
53			#include "mystring.h"
54
55			#ifdef HETIO
56			#include "hetio.h"
57			#endif
58
59			/*
60			* Sigmode records the current value of the signal handlers for the various
61			* modes. A value of zero means that the current handler is not known.
62			* S_HARD_IGN indicates that the signal was ignored on entry to the shell,
63			*/
64
65			#define S_DFL 1 /* default signal handling (SIG_DFL) */
66			#define S_CATCH 2 /* signal is caught */
67			#define S_IGN 3 /* signal is ignored (SIG_IGN) */
68			#define S_HARD_IGN 4 /* signal is ignored permenantly */
69			#define S_RESET 5 /* temporary - to reset a hard ignored sig */
70
71
72			/* trap handler commands */
73			char *trap[NSIG];
74			/* current value of signal */
75			static char sigmode[NSIG - 1];
76			/* indicates specified signal received */
77			char gotsig[NSIG - 1];
78			/* last pending signal */
79			volatile sig_atomic_t pendingsigs;
80			/* do we generate EXSIG events */
81			int exsig;
82
83			#ifdef mkinit
84			INCLUDE <signal.h>
85			INIT {
86			signal(SIGCHLD, SIG_DFL);
87			}
88			#endif
89
90			/*
91			* The trap builtin.
92			*/
93
94			int
95			trapcmd(int argc, char **argv)
96			{
97			char *action;
98			char **ap;
99			int signo;
100
101			nextopt(nullstr);
102			ap = argptr;
103			if (!*ap) {
104			for (signo = 0 ; signo < NSIG ; signo++) {
105			if (trap[signo] != NULL) {
106			out1fmt(
107			"trap -- %s %s\n",
108			single_quote(trap[signo]),
109			signal_name(signo)
110			);
111			}
112			}
113			return 0;
114			}
115			if (!ap[1])
116			action = NULL;
117			else
118			action = *ap++;
119			while (*ap) {
120			if ((signo = decode_signal(*ap, 0)) < 0)
121			sh_error("%s: bad trap", *ap);
122			INTOFF;
123			if (action) {
124			if (action[0] == '-' && action[1] == '\0')
125			action = NULL;
126			else
127			action = savestr(action);
128			}
129			if (trap[signo])
130			ckfree(trap[signo]);
131			trap[signo] = action;
132			if (signo != 0)
133			setsignal(signo);
134			INTON;
135			ap++;
136			}
137			return 0;
138			}
139
140
141
142			/*
143			* Clear traps on a fork.
144			*/
145
146			void
147			clear_traps(void)
148			{
149			char **tp;
150
151			for (tp = trap ; tp < &trap[NSIG] ; tp++) {
152			if (tp && tp) { / trap not NULL or SIG_IGN */
153			INTOFF;
154			ckfree(*tp);
155			*tp = NULL;
156			if (tp != &trap[0])
157			setsignal(tp - trap);
158			INTON;
159			}
160			}
161			}
162
163
164
165			/*
166			* Set the signal handler for the specified signal. The routine figures
167			* out what it should be set to.
168			*/
169
170			void
171			setsignal(int signo)
172			{
173			int action;
174			char *t, tsig;
175			struct sigaction act;
176
177			if ((t = trap[signo]) == NULL)
178			action = S_DFL;
179			else if (*t != '\0')
180			action = S_CATCH;
181			else
182			action = S_IGN;
183			if (rootshell && action == S_DFL) {
184			switch (signo) {
185			case SIGINT:
186			if (iflag \|\| minusc \|\| sflag == 0)
187			action = S_CATCH;
188			break;
189			case SIGQUIT:
190			#ifdef DEBUG
191			if (debug)
192			break;
193			#endif
194			/* FALLTHROUGH */
195			case SIGTERM:
196			if (iflag)
197			action = S_IGN;
198			break;
199			#if JOBS
200			case SIGTSTP:
201			case SIGTTOU:
202			if (mflag)
203			action = S_IGN;
204			break;
205			#endif
206			}
207			}
208
209			t = &sigmode[signo - 1];
210			tsig = *t;
211			if (tsig == 0) {
212			/*
213			* current setting unknown
214			*/
215			if (sigaction(signo, 0, &act) == -1) {
216			/*
217			* Pretend it worked; maybe we should give a warning
218			* here, but other shells don't. We don't alter
219			* sigmode, so that we retry every time.
220			*/
221			return;
222			}
223			if (act.sa_handler == SIG_IGN) {
224			if (mflag && (signo == SIGTSTP \|\|
225			signo == SIGTTIN \|\| signo == SIGTTOU)) {
226			tsig = S_IGN; /* don't hard ignore these */
227			} else
228			tsig = S_HARD_IGN;
229			} else {
230			tsig = S_RESET; /* force to be set */
231			}
232			}
233			if (tsig == S_HARD_IGN \|\| tsig == action)
234			return;
235			switch (action) {
236			case S_CATCH:
237			act.sa_handler = onsig;
238			break;
239			case S_IGN:
240			act.sa_handler = SIG_IGN;
241			break;
242			default:
243			act.sa_handler = SIG_DFL;
244			}
245			*t = action;
246			act.sa_flags = 0;
247			sigfillset(&act.sa_mask);
248			sigaction(signo, &act, 0);
249			}
250
251			/*
252			* Ignore a signal.
253			*/
254
255			void
256			ignoresig(int signo)
257			{
258			if (sigmode[signo - 1] != S_IGN && sigmode[signo - 1] != S_HARD_IGN) {
259			signal(signo, SIG_IGN);
260			}
261			sigmode[signo - 1] = S_HARD_IGN;
262			}
263
264
265
266			/*
267			* Signal handler.
268			*/
269
270			void
271			onsig(int signo)
272			{
273			gotsig[signo - 1] = 1;
274			pendingsigs = signo;
275
276			if (exsig \|\| (signo == SIGINT && !trap[SIGINT])) {
277			if (!suppressint)
278			onint();
279			intpending = 1;
280			}
281			}
282
283
284
285			/*
286			* Called to execute a trap. Perhaps we should avoid entering new trap
287			* handlers while we are executing a trap handler.
288			*/
289
290			int
291			dotrap(void)
292			{
293			char *p;
294			char *q;
295			int i;
296			int savestatus;
297
298			savestatus = exitstatus;
299			pendingsigs = 0;
300			barrier();
301
302			for (i = 0, q = gotsig; i < NSIG - 1; i++, q++) {
303			if (!*q)
304			continue;
305			*q = 0;
306
307			p = trap[i + 1];
308			if (!p)
309			continue;
310	niro	815	evalstring(p, SKIPEVAL);
311	niro	532	exitstatus = savestatus;
312	niro	815	if (evalskip)
313			return evalskip;
314	niro	532	}
315
316	niro	815	return 0;
317	niro	532	}
318
319
320
321			/*
322			* Controls whether the shell is interactive or not.
323			*/
324
325
326			void
327			setinteractive(int on)
328			{
329			static int is_interactive;
330
331			if (++on == is_interactive)
332			return;
333			is_interactive = on;
334			setsignal(SIGINT);
335			setsignal(SIGQUIT);
336			setsignal(SIGTERM);
337			}
338
339
340
341			/*
342			* Called to exit the shell.
343			*/
344
345			void
346			exitshell(void)
347			{
348			struct jmploc loc;
349			char *p;
350			int status;
351
352			#ifdef HETIO
353			hetio_reset_term();
354			#endif
355			status = exitstatus;
356			TRACE(("pid %d, exitshell(%d)\n", getpid(), status));
357			if (setjmp(loc.loc)) {
358			if (exception == EXEXIT)
359			_exit(exitstatus);
360			goto out;
361			}
362			handler = &loc;
363			if ((p = trap[0])) {
364			trap[0] = NULL;
365			evalstring(p, 0);
366			}
367			flushall();
368			out:
369			_exit(status);
370			/* NOTREACHED */
371			}
372
373			/*
374			* Decode a signal name
375			*/
376			int decode_signal(const char *string, int minsig)
377			{
378			int i;
379
380			if (is_number(string)) {
381			i = atoi(string);
382			if (i >= NSIG) {
383			return -1;
384			}
385			return i;
386			}
387
388			for ( i = minsig ; i < NSIG ; i++ ) {
389			if ( sys_sigabbrev[i] &&
390			!strcasecmp(string, sys_sigabbrev[i]) )
391			return i;
392			}
393
394			#ifdef SIGRTMIN
395			if ( !strncasecmp(string, "RTMIN", 5) ) {
396			char *ep;
397
398			if ( string[5] && string[5] != '+' )
399			return -1;
400			i = SIGRTMIN + strtol(string+5, &ep, 10);
401			if ( *ep \|\| i < SIGRTMIN \|\| i > SIGRTMAX )
402			return -1;
403			return i;
404			}
405
406			if ( !strncasecmp(string, "RTMAX", 5) ) {
407			char *ep;
408
409			if ( string[5] && string[5] != '-' )
410			return -1;
411			i = SIGRTMAX + strtol(string+5, &ep, 10);
412			if ( *ep \|\| i < SIGRTMIN \|\| i > SIGRTMAX )
413			return -1;
414			return i;
415			}
416			#endif
417
418			return -1;
419			}
420
421			/*
422			* Human-readable signal name
423			*/
424			const char *
425			signal_name(int sig)
426			{
427			static char buf[64];
428
429			if ( sig < 0 \|\| sig >= NSIG ) {
430			return NULL;
431			} else if ( sys_sigabbrev[sig] ) {
432			return sys_sigabbrev[sig];
433			#ifdef SIGRTMIN
434			} else if ( sig >= SIGRTMIN && sig <= SIGRTMAX ) {
435			snprintf(buf, sizeof buf, "RTMIN+%d", sig-SIGRTMIN);
436			return buf;
437			#endif
438			} else {
439			snprintf(buf, sizeof buf, "%d", sig);
440			return buf;
441			}
442			}