[apple/shell_cmds.git] / sh / redir.c

/*-
 * 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.
 * 4. 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[] = "@(#)redir.c	8.2 (Berkeley) 5/4/95";
#endif
#endif /* not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: head/bin/sh/redir.c 295085 2016-01-30 21:21:25Z jilles $");

#include <sys/types.h>
#include <sys/stat.h>
#include <signal.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>

/*
 * Code for dealing with input/output redirection.
 */

#include "shell.h"
#include "nodes.h"
#include "jobs.h"
#include "expand.h"
#include "redir.h"
#include "output.h"
#include "memalloc.h"
#include "error.h"
#include "options.h"


#define EMPTY -2		/* marks an unused slot in redirtab */
#define CLOSED -1		/* fd was not open before redir */


struct redirtab {
	struct redirtab *next;
	int renamed[10];
	int fd0_redirected;
	unsigned int empty_redirs;
};


static struct redirtab *redirlist;

/*
 * We keep track of whether or not fd0 has been redirected.  This is for
 * background commands, where we want to redirect fd0 to /dev/null only
 * if it hasn't already been redirected.
*/
static int fd0_redirected = 0;

/* Number of redirtabs that have not been allocated. */
static unsigned int empty_redirs = 0;

static void openredirect(union node *, char[10 ]);
static int openhere(union node *);


/*
 * Process a list of redirection commands.  If the REDIR_PUSH flag is set,
 * old file descriptors are stashed away so that the redirection can be
 * undone by calling popredir.  If the REDIR_BACKQ flag is set, then the
 * standard output, and the standard error if it becomes a duplicate of
 * stdout, is saved in memory.
*
 * We suppress interrupts so that we won't leave open file
 * descriptors around.  Because the signal handler remains
 * installed and we do not use system call restart, interrupts
 * will still abort blocking opens such as fifos (they will fail
 * with EINTR). There is, however, a race condition if an interrupt
 * arrives after INTOFF and before open blocks.
 */

void
redirect(union node *redir, int flags)
{
	union node *n;
	struct redirtab *sv = NULL;
	int i;
	int fd;
	char memory[10];	/* file descriptors to write to memory */

	INTOFF;
	for (i = 10 ; --i >= 0 ; )
		memory[i] = 0;
	memory[1] = flags & REDIR_BACKQ;
	if (flags & REDIR_PUSH) {
		empty_redirs++;
		if (redir != NULL) {
			sv = ckmalloc(sizeof (struct redirtab));
			for (i = 0 ; i < 10 ; i++)
				sv->renamed[i] = EMPTY;
			sv->fd0_redirected = fd0_redirected;
			sv->empty_redirs = empty_redirs - 1;
			sv->next = redirlist;
			redirlist = sv;
			empty_redirs = 0;
		}
	}
	for (n = redir ; n ; n = n->nfile.next) {
		fd = n->nfile.fd;
		if (fd == 0)
			fd0_redirected = 1;
		if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) &&
		    n->ndup.dupfd == fd)
			continue; /* redirect from/to same file descriptor */

		if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) {
			INTOFF;
			if ((i = fcntl(fd, F_DUPFD_CLOEXEC, 10)) == -1) {
				switch (errno) {
				case EBADF:
					i = CLOSED;
					break;
				default:
					INTON;
					error("%d: %s", fd, strerror(errno));
					break;
				}
			}
			sv->renamed[fd] = i;
			INTON;
		}
		openredirect(n, memory);
		INTON;
		INTOFF;
	}
	if (memory[1])
		out1 = &memout;
	if (memory[2])
		out2 = &memout;
	INTON;
}


static void
openredirect(union node *redir, char memory[10])
{
	struct stat sb;
	int fd = redir->nfile.fd;
	const char *fname;
	int f;
	int e;

	memory[fd] = 0;
	switch (redir->nfile.type) {
	case NFROM:
		fname = redir->nfile.expfname;
		if ((f = open(fname, O_RDONLY)) < 0)
			error("cannot open %s: %s", fname, strerror(errno));
		break;
	case NFROMTO:
		fname = redir->nfile.expfname;
		if ((f = open(fname, O_RDWR|O_CREAT, 0666)) < 0)
			error("cannot create %s: %s", fname, strerror(errno));
		break;
	case NTO:
		if (Cflag) {
			fname = redir->nfile.expfname;
			if (stat(fname, &sb) == -1) {
				if ((f = open(fname, O_WRONLY|O_CREAT|O_EXCL, 0666)) < 0)
					error("cannot create %s: %s", fname, strerror(errno));
			} else if (!S_ISREG(sb.st_mode)) {
				if ((f = open(fname, O_WRONLY, 0666)) < 0)
					error("cannot create %s: %s", fname, strerror(errno));
				if (fstat(f, &sb) != -1 && S_ISREG(sb.st_mode)) {
					close(f);
					error("cannot create %s: %s", fname,
					    strerror(EEXIST));
				}
			} else
				error("cannot create %s: %s", fname,
				    strerror(EEXIST));
			break;
		}
		/* FALLTHROUGH */
	case NCLOBBER:
		fname = redir->nfile.expfname;
		if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0)
			error("cannot create %s: %s", fname, strerror(errno));
		break;
	case NAPPEND:
		fname = redir->nfile.expfname;
		if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0)
			error("cannot create %s: %s", fname, strerror(errno));
		break;
	case NTOFD:
	case NFROMFD:
		if (redir->ndup.dupfd >= 0) {	/* if not ">&-" */
			if (memory[redir->ndup.dupfd])
				memory[fd] = 1;
			else {
				if (dup2(redir->ndup.dupfd, fd) < 0)
					error("%d: %s", redir->ndup.dupfd,
							strerror(errno));
			}
		} else {
			close(fd);
		}
		return;
	case NHERE:
	case NXHERE:
		f = openhere(redir);
		break;
	default:
		abort();
	}
	if (f != fd) {
		if (dup2(f, fd) == -1) {
			e = errno;
			close(f);
			error("%d: %s", fd, strerror(e));
		}
		close(f);
	}
}


/*
 * Handle here documents.  Normally we fork off a process to write the
 * data to a pipe.  If the document is short, we can stuff the data in
 * the pipe without forking.
 */

static int
openhere(union node *redir)
{
	const char *p;
	int pip[2];
	size_t len = 0;
	int flags;
	ssize_t written = 0;

	if (pipe(pip) < 0)
		error("Pipe call failed: %s", strerror(errno));

	if (redir->type == NXHERE)
		p = redir->nhere.expdoc;
	else
		p = redir->nhere.doc->narg.text;
	len = strlen(p);
	if (len == 0)
		goto out;
	flags = fcntl(pip[1], F_GETFL, 0);
	if (flags != -1 && fcntl(pip[1], F_SETFL, flags | O_NONBLOCK) != -1) {
		written = write(pip[1], p, len);
		if (written < 0)
			written = 0;
		if ((size_t)written == len)
			goto out;
		fcntl(pip[1], F_SETFL, flags);
	}

	if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) {
		close(pip[0]);
		signal(SIGINT, SIG_IGN);
		signal(SIGQUIT, SIG_IGN);
		signal(SIGHUP, SIG_IGN);
		signal(SIGTSTP, SIG_IGN);
		signal(SIGPIPE, SIG_DFL);
		xwrite(pip[1], p + written, len - written);
		_exit(0);
	}
out:
	close(pip[1]);
	return pip[0];
}


/*
 * Undo the effects of the last redirection.
 */

void
popredir(void)
{
	struct redirtab *rp = redirlist;
	int i;

	INTOFF;
	if (empty_redirs > 0) {
		empty_redirs--;
		INTON;
		return;
	}
	for (i = 0 ; i < 10 ; i++) {
		if (rp->renamed[i] != EMPTY) {
			if (rp->renamed[i] >= 0) {
				dup2(rp->renamed[i], i);
				close(rp->renamed[i]);
			} else {
				close(i);
			}
		}
	}
	fd0_redirected = rp->fd0_redirected;
	empty_redirs = rp->empty_redirs;
	redirlist = rp->next;
	ckfree(rp);
	INTON;
}

/* Return true if fd 0 has already been redirected at least once.  */
int
fd0_redirected_p(void)
{
        return fd0_redirected != 0;
}

/*
 * Discard all saved file descriptors.
 */

void
clearredir(void)
{
	struct redirtab *rp;
	int i;

	for (rp = redirlist ; rp ; rp = rp->next) {
		for (i = 0 ; i < 10 ; i++) {
			if (rp->renamed[i] >= 0) {
				close(rp->renamed[i]);
			}
			rp->renamed[i] = EMPTY;
		}
	}
}
Commit	Line	Data
71aad674 A	1	/*-
	2	* Copyright (c) 1991, 1993
	3	* The Regents of the University of California. All rights reserved.
	4	*
	5	* This code is derived from software contributed to Berkeley by
	6	* Kenneth Almquist.
	7	*
	8	* Redistribution and use in source and binary forms, with or without
	9	* modification, are permitted provided that the following conditions
	10	* are met:
	11	* 1. Redistributions of source code must retain the above copyright
	12	* notice, this list of conditions and the following disclaimer.
	13	* 2. Redistributions in binary form must reproduce the above copyright
	14	* notice, this list of conditions and the following disclaimer in the
	15	* documentation and/or other materials provided with the distribution.
	16	* 4. Neither the name of the University nor the names of its contributors
	17	* may be used to endorse or promote products derived from this software
	18	* without specific prior written permission.
	19	*
	20	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	21	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	22	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	23	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	24	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	25	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	26	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	27	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	28	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	29	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	30	* SUCH DAMAGE.
	31	*/
	32
	33	#ifndef lint
	34	#if 0
	35	static char sccsid[] = "@(#)redir.c 8.2 (Berkeley) 5/4/95";
	36	#endif
	37	#endif /* not lint */
	38	#include <sys/cdefs.h>
deb63bfb	39	__FBSDID("$FreeBSD: head/bin/sh/redir.c 295085 2016-01-30 21:21:25Z jilles $");
71aad674 A	40
	41	#include <sys/types.h>
	42	#include <sys/stat.h>
	43	#include <signal.h>
	44	#include <string.h>
	45	#include <fcntl.h>
	46	#include <errno.h>
	47	#include <unistd.h>
	48	#include <stdlib.h>
	49
	50	/*
	51	* Code for dealing with input/output redirection.
	52	*/
	53
	54	#include "shell.h"
	55	#include "nodes.h"
	56	#include "jobs.h"
	57	#include "expand.h"
	58	#include "redir.h"
	59	#include "output.h"
	60	#include "memalloc.h"
	61	#include "error.h"
	62	#include "options.h"
	63
	64
	65	#define EMPTY -2 /* marks an unused slot in redirtab */
	66	#define CLOSED -1 /* fd was not open before redir */
	67
	68
	69	struct redirtab {
	70	struct redirtab *next;
	71	int renamed[10];
	72	int fd0_redirected;
deb63bfb	73	unsigned int empty_redirs;
71aad674 A	74	};
	75
	76
	77	static struct redirtab *redirlist;
	78
	79	/*
	80	* We keep track of whether or not fd0 has been redirected. This is for
	81	* background commands, where we want to redirect fd0 to /dev/null only
	82	* if it hasn't already been redirected.
	83	*/
	84	static int fd0_redirected = 0;
	85
deb63bfb A	86	/* Number of redirtabs that have not been allocated. */
	87	static unsigned int empty_redirs = 0;
	88
71aad674 A	89	static void openredirect(union node *, char[10 ]);
	90	static int openhere(union node *);
	91
	92
	93	/*
	94	* Process a list of redirection commands. If the REDIR_PUSH flag is set,
	95	* old file descriptors are stashed away so that the redirection can be
	96	* undone by calling popredir. If the REDIR_BACKQ flag is set, then the
	97	* standard output, and the standard error if it becomes a duplicate of
	98	* stdout, is saved in memory.
	99	*
	100	* We suppress interrupts so that we won't leave open file
	101	* descriptors around. Because the signal handler remains
	102	* installed and we do not use system call restart, interrupts
	103	* will still abort blocking opens such as fifos (they will fail
	104	* with EINTR). There is, however, a race condition if an interrupt
	105	* arrives after INTOFF and before open blocks.
	106	*/
	107
	108	void
	109	redirect(union node *redir, int flags)
	110	{
	111	union node *n;
	112	struct redirtab *sv = NULL;
	113	int i;
	114	int fd;
	115	char memory[10]; /* file descriptors to write to memory */
	116
	117	INTOFF;
	118	for (i = 10 ; --i >= 0 ; )
	119	memory[i] = 0;
	120	memory[1] = flags & REDIR_BACKQ;
	121	if (flags & REDIR_PUSH) {
deb63bfb A	122	empty_redirs++;
	123	if (redir != NULL) {
	124	sv = ckmalloc(sizeof (struct redirtab));
	125	for (i = 0 ; i < 10 ; i++)
	126	sv->renamed[i] = EMPTY;
	127	sv->fd0_redirected = fd0_redirected;
	128	sv->empty_redirs = empty_redirs - 1;
	129	sv->next = redirlist;
	130	redirlist = sv;
	131	empty_redirs = 0;
	132	}
71aad674 A	133	}
	134	for (n = redir ; n ; n = n->nfile.next) {
	135	fd = n->nfile.fd;
	136	if (fd == 0)
	137	fd0_redirected = 1;
	138	if ((n->nfile.type == NTOFD \|\| n->nfile.type == NFROMFD) &&
	139	n->ndup.dupfd == fd)
	140	continue; /* redirect from/to same file descriptor */
	141
	142	if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) {
	143	INTOFF;
	144	if ((i = fcntl(fd, F_DUPFD_CLOEXEC, 10)) == -1) {
	145	switch (errno) {
	146	case EBADF:
	147	i = CLOSED;
	148	break;
	149	default:
	150	INTON;
	151	error("%d: %s", fd, strerror(errno));
	152	break;
	153	}
	154	}
	155	sv->renamed[fd] = i;
	156	INTON;
	157	}
	158	openredirect(n, memory);
	159	INTON;
	160	INTOFF;
	161	}
	162	if (memory[1])
	163	out1 = &memout;
	164	if (memory[2])
	165	out2 = &memout;
	166	INTON;
	167	}
	168
	169
	170	static void
	171	openredirect(union node *redir, char memory[10])
	172	{
	173	struct stat sb;
	174	int fd = redir->nfile.fd;
	175	const char *fname;
	176	int f;
	177	int e;
	178
	179	memory[fd] = 0;
	180	switch (redir->nfile.type) {
	181	case NFROM:
	182	fname = redir->nfile.expfname;
	183	if ((f = open(fname, O_RDONLY)) < 0)
	184	error("cannot open %s: %s", fname, strerror(errno));
	185	break;
	186	case NFROMTO:
	187	fname = redir->nfile.expfname;
	188	if ((f = open(fname, O_RDWR\|O_CREAT, 0666)) < 0)
	189	error("cannot create %s: %s", fname, strerror(errno));
	190	break;
	191	case NTO:
	192	if (Cflag) {
	193	fname = redir->nfile.expfname;
	194	if (stat(fname, &sb) == -1) {
	195	if ((f = open(fname, O_WRONLY\|O_CREAT\|O_EXCL, 0666)) < 0)
	196	error("cannot create %s: %s", fname, strerror(errno));
197	} else if (!S_ISREG(sb.st_mode)) {
198	if ((f = open(fname, O_WRONLY, 0666)) < 0)
199	error("cannot create %s: %s", fname, strerror(errno));
200	if (fstat(f, &sb) != -1 && S_ISREG(sb.st_mode)) {
201	close(f);
202	error("cannot create %s: %s", fname,
203	strerror(EEXIST));
204	}
205	} else
206	error("cannot create %s: %s", fname,
207	strerror(EEXIST));
208	break;
209	}
210	/* FALLTHROUGH */
211	case NCLOBBER:
212	fname = redir->nfile.expfname;
213	if ((f = open(fname, O_WRONLY\|O_CREAT\|O_TRUNC, 0666)) < 0)
214	error("cannot create %s: %s", fname, strerror(errno));
215	break;
216	case NAPPEND:
217	fname = redir->nfile.expfname;
218	if ((f = open(fname, O_WRONLY\|O_CREAT\|O_APPEND, 0666)) < 0)
219	error("cannot create %s: %s", fname, strerror(errno));
220	break;
221	case NTOFD:
222	case NFROMFD:
223	if (redir->ndup.dupfd >= 0) { /* if not ">&-" */
224	if (memory[redir->ndup.dupfd])
225	memory[fd] = 1;
226	else {
227	if (dup2(redir->ndup.dupfd, fd) < 0)
228	error("%d: %s", redir->ndup.dupfd,
229	strerror(errno));
230	}
231	} else {
232	close(fd);
233	}
234	return;
235	case NHERE:
236	case NXHERE:
237	f = openhere(redir);
238	break;
239	default:
240	abort();
241	}
242	if (f != fd) {
243	if (dup2(f, fd) == -1) {
244	e = errno;
245	close(f);
246	error("%d: %s", fd, strerror(e));
247	}
248	close(f);
249	}
250	}
251
252
253	/*
254	* Handle here documents. Normally we fork off a process to write the
255	* data to a pipe. If the document is short, we can stuff the data in
256	* the pipe without forking.
257	*/
258
259	static int
260	openhere(union node *redir)
261	{
262	const char *p;
263	int pip[2];
264	size_t len = 0;
265	int flags;
266	ssize_t written = 0;
267
268	if (pipe(pip) < 0)
269	error("Pipe call failed: %s", strerror(errno));
270
271	if (redir->type == NXHERE)
272	p = redir->nhere.expdoc;
273	else
274	p = redir->nhere.doc->narg.text;
275	len = strlen(p);
276	if (len == 0)
277	goto out;
278	flags = fcntl(pip[1], F_GETFL, 0);
279	if (flags != -1 && fcntl(pip[1], F_SETFL, flags \| O_NONBLOCK) != -1) {
280	written = write(pip[1], p, len);
281	if (written < 0)
282	written = 0;
283	if ((size_t)written == len)
284	goto out;
285	fcntl(pip[1], F_SETFL, flags);
286	}
287
288	if (forkshell((struct job )NULL, (union node )NULL, FORK_NOJOB) == 0) {
289	close(pip[0]);
290	signal(SIGINT, SIG_IGN);
291	signal(SIGQUIT, SIG_IGN);
292	signal(SIGHUP, SIG_IGN);
293	signal(SIGTSTP, SIG_IGN);
294	signal(SIGPIPE, SIG_DFL);
295	xwrite(pip[1], p + written, len - written);
296	_exit(0);
297	}
298	out:
299	close(pip[1]);
300	return pip[0];
301	}
302
303
304
305	/*
306	* Undo the effects of the last redirection.
307	*/
308
309	void
310	popredir(void)
311	{
312	struct redirtab *rp = redirlist;
313	int i;
314
deb63bfb A	315	INTOFF;
	316	if (empty_redirs > 0) {
	317	empty_redirs--;
	318	INTON;
	319	return;
	320	}
71aad674 A	321	for (i = 0 ; i < 10 ; i++) {
	322	if (rp->renamed[i] != EMPTY) {
	323	if (rp->renamed[i] >= 0) {
	324	dup2(rp->renamed[i], i);
	325	close(rp->renamed[i]);
	326	} else {
	327	close(i);
	328	}
	329	}
	330	}
71aad674	331	fd0_redirected = rp->fd0_redirected;
deb63bfb	332	empty_redirs = rp->empty_redirs;
71aad674 A	333	redirlist = rp->next;
	334	ckfree(rp);
	335	INTON;
	336	}
	337
	338	/* Return true if fd 0 has already been redirected at least once. */
	339	int
	340	fd0_redirected_p(void)
	341	{
	342	return fd0_redirected != 0;
	343	}
	344
	345	/*
	346	* Discard all saved file descriptors.
	347	*/
	348
	349	void
	350	clearredir(void)
	351	{
	352	struct redirtab *rp;
	353	int i;
	354
	355	for (rp = redirlist ; rp ; rp = rp->next) {
	356	for (i = 0 ; i < 10 ; i++) {
	357	if (rp->renamed[i] >= 0) {
	358	close(rp->renamed[i]);
	359	}
	360	rp->renamed[i] = EMPTY;
	361	}
	362	}
	363	}