[unix-history] / usr / src / bin / sh / redir.c

/*-
 * Copyright (c) 1991 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 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
static char sccsid[] = "@(#)redir.c	5.1 (Berkeley) 3/7/91";
#endif /* not lint */

/*
 * 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 <signal.h>
#include <fcntl.h>
#include <errno.h>


#define EMPTY -2		/* marks an unused slot in redirtab */
#define PIPESIZE 4096		/* amount of buffering in a pipe */


MKINIT
struct redirtab {
	struct redirtab *next;
	short renamed[10];
};


MKINIT struct redirtab *redirlist;


#ifdef __STDC__
STATIC void openredirect(union node *, char *);
STATIC int openhere(union node *);
#else
STATIC void openredirect();
STATIC int openhere();
#endif


/*
 * 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.
 */

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

	for (i = 10 ; --i >= 0 ; )
		memory[i] = 0;
	memory[1] = flags & REDIR_BACKQ;
	if (flags & REDIR_PUSH) {
		sv = ckmalloc(sizeof (struct redirtab));
		for (i = 0 ; i < 10 ; i++)
			sv->renamed[i] = EMPTY;
		sv->next = redirlist;
		redirlist = sv;
	}
	for (n = redir ; n ; n = n->nfile.next) {
		fd = n->nfile.fd;
		if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) {
			INTOFF;
			if ((i = copyfd(fd, 10)) != EMPTY) {
				sv->renamed[fd] = i;
				close(fd);
			}
			INTON;
			if (i == EMPTY)
				error("Out of file descriptors");
		} else {
			close(fd);
		}
		openredirect(n, memory);
	}
	if (memory[1])
		out1 = &memout;
	if (memory[2])
		out2 = &memout;
}


STATIC void
openredirect(redir, memory)
	union node *redir;
	char memory[10];
	{
	int fd = redir->nfile.fd;
	char *fname;
	int f;

	/*
	 * We suppress interrupts so that we won't leave open file
	 * descriptors around.  This may not be such a good idea because
	 * an open of a device or a fifo can block indefinitely.
	 */
	INTOFF;
	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, errmsg(errno, E_OPEN));
movefd:
		if (f != fd) {
			copyfd(f, fd);
			close(f);
		}
		break;
	case NTO:
		fname = redir->nfile.expfname;
#ifdef O_CREAT
		if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0)
			error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
#else
		if ((f = creat(fname, 0666)) < 0)
			error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
#endif
		goto movefd;
	case NAPPEND:
		fname = redir->nfile.expfname;
#ifdef O_APPEND
		if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0)
			error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
#else
		if ((f = open(fname, O_WRONLY)) < 0
		 && (f = creat(fname, 0666)) < 0)
			error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
		lseek(f, 0L, 2);
#endif
		goto movefd;
	case NTOFD:
	case NFROMFD:
		if (redir->ndup.dupfd >= 0) {	/* if not ">&-" */
			if (memory[redir->ndup.dupfd])
				memory[fd] = 1;
			else
				copyfd(redir->ndup.dupfd, fd);
		}
		break;
	case NHERE:
	case NXHERE:
		f = openhere(redir);
		goto movefd;
	default:
		abort();
	}
	INTON;
}


/*
 * 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(redir)
	union node *redir;
	{
	int pip[2];
	int len;

	if (pipe(pip) < 0)
		error("Pipe call failed");
	if (redir->type == NHERE) {
		len = strlen(redir->nhere.doc->narg.text);
		if (len <= PIPESIZE) {
			xwrite(pip[1], redir->nhere.doc->narg.text, len);
			goto out;
		}
	}
	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);
#ifdef SIGTSTP
		signal(SIGTSTP, SIG_IGN);
#endif
		signal(SIGPIPE, SIG_DFL);
		if (redir->type == NHERE)
			xwrite(pip[1], redir->nhere.doc->narg.text, len);
		else
			expandhere(redir->nhere.doc, pip[1]);
		_exit(0);
	}
out:
	close(pip[1]);
	return pip[0];
}


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

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

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


/*
 * Undo all redirections.  Called on error or interrupt.
 */

#ifdef mkinit

INCLUDE "redir.h"

RESET {
	while (redirlist)
		popredir();
}

SHELLPROC {
	clearredir();
}

#endif


/*
 * Discard all saved file descriptors.
 */

void
clearredir() {
	register 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;
		}
	}
}


/*
 * Copy a file descriptor, like the F_DUPFD option of fcntl.  Returns -1
 * if the source file descriptor is closed, EMPTY if there are no unused
 * file descriptors left.
 */

int
copyfd(from, to) {
#ifdef F_DUPFD
	int newfd;

	newfd = fcntl(from, F_DUPFD, to);
	if (newfd < 0 && errno == EMFILE)
		return EMPTY;
	return newfd;
#else
	char toclose[32];
	int i;
	int newfd;
	int e;

	for (i = 0 ; i < to ; i++)
		toclose[i] = 0;
	INTOFF;
	while ((newfd = dup(from)) >= 0 && newfd < to)
		toclose[newfd] = 1;
	e = errno;
	for (i = 0 ; i < to ; i++) {
		if (toclose[i])
			close(i);
	}
	INTON;
	if (newfd < 0 && e == EMFILE)
		return EMPTY;
	return newfd;
#endif
}
Commit	Line	Data
af3e82f7 WJ	1	/*-
	2	* Copyright (c) 1991 The Regents of the University of California.
	3	* 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	* 3. All advertising materials mentioning features or use of this software
	17	* must display the following acknowledgement:
	18	* This product includes software developed by the University of
	19	* California, Berkeley and its contributors.
	20	* 4. Neither the name of the University nor the names of its contributors
	21	* may be used to endorse or promote products derived from this software
	22	* without specific prior written permission.
	23	*
	24	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	25	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	26	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	27	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	28	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	29	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	30	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	31	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	32	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	33	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	34	* SUCH DAMAGE.
	35	*/
	36
	37	#ifndef lint
	38	static char sccsid[] = "@(#)redir.c 5.1 (Berkeley) 3/7/91";
	39	#endif /* not lint */
	40
	41	/*
	42	* Code for dealing with input/output redirection.
	43	*/
	44
	45	#include "shell.h"
	46	#include "nodes.h"
	47	#include "jobs.h"
	48	#include "expand.h"
	49	#include "redir.h"
	50	#include "output.h"
	51	#include "memalloc.h"
	52	#include "error.h"
	53	#include <signal.h>
	54	#include <fcntl.h>
	55	#include <errno.h>
	56
	57
	58	#define EMPTY -2 /* marks an unused slot in redirtab */
	59	#define PIPESIZE 4096 /* amount of buffering in a pipe */
	60
	61
	62	MKINIT
	63	struct redirtab {
	64	struct redirtab *next;
65	short renamed[10];
66	};
67
68
69	MKINIT struct redirtab *redirlist;
70
71
72	#ifdef __STDC__
73	STATIC void openredirect(union node , char );
74	STATIC int openhere(union node *);
75	#else
76	STATIC void openredirect();
77	STATIC int openhere();
78	#endif
79
80
81
82	/*
83	* Process a list of redirection commands. If the REDIR_PUSH flag is set,
84	* old file descriptors are stashed away so that the redirection can be
85	* undone by calling popredir. If the REDIR_BACKQ flag is set, then the
86	* standard output, and the standard error if it becomes a duplicate of
87	* stdout, is saved in memory.
88	*/
89
90	void
91	redirect(redir, flags)
92	union node *redir;
93	int flags;
94	{
95	union node *n;
96	struct redirtab *sv;
97	int i;
98	int fd;
99	char memory[10]; /* file descriptors to write to memory */
100
101	for (i = 10 ; --i >= 0 ; )
102	memory[i] = 0;
103	memory[1] = flags & REDIR_BACKQ;
104	if (flags & REDIR_PUSH) {
105	sv = ckmalloc(sizeof (struct redirtab));
106	for (i = 0 ; i < 10 ; i++)
107	sv->renamed[i] = EMPTY;
108	sv->next = redirlist;
109	redirlist = sv;
110	}
111	for (n = redir ; n ; n = n->nfile.next) {
112	fd = n->nfile.fd;
113	if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) {
114	INTOFF;
115	if ((i = copyfd(fd, 10)) != EMPTY) {
116	sv->renamed[fd] = i;
117	close(fd);
118	}
119	INTON;
120	if (i == EMPTY)
121	error("Out of file descriptors");
122	} else {
123	close(fd);
124	}
125	openredirect(n, memory);
126	}
127	if (memory[1])
128	out1 = &memout;
129	if (memory[2])
130	out2 = &memout;
131	}
132
133
134	STATIC void
135	openredirect(redir, memory)
136	union node *redir;
137	char memory[10];
138	{
139	int fd = redir->nfile.fd;
140	char *fname;
141	int f;
142
143	/*
144	* We suppress interrupts so that we won't leave open file
145	* descriptors around. This may not be such a good idea because
146	* an open of a device or a fifo can block indefinitely.
147	*/
148	INTOFF;
149	memory[fd] = 0;
150	switch (redir->nfile.type) {
151	case NFROM:
152	fname = redir->nfile.expfname;
153	if ((f = open(fname, O_RDONLY)) < 0)
154	error("cannot open %s: %s", fname, errmsg(errno, E_OPEN));
155	movefd:
156	if (f != fd) {
157	copyfd(f, fd);
158	close(f);
159	}
160	break;
161	case NTO:
162	fname = redir->nfile.expfname;
163	#ifdef O_CREAT
164	if ((f = open(fname, O_WRONLY\|O_CREAT\|O_TRUNC, 0666)) < 0)
165	error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
166	#else
167	if ((f = creat(fname, 0666)) < 0)
168	error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
169	#endif
170	goto movefd;
171	case NAPPEND:
172	fname = redir->nfile.expfname;
173	#ifdef O_APPEND
174	if ((f = open(fname, O_WRONLY\|O_CREAT\|O_APPEND, 0666)) < 0)
175	error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
176	#else
177	if ((f = open(fname, O_WRONLY)) < 0
178	&& (f = creat(fname, 0666)) < 0)
179	error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
180	lseek(f, 0L, 2);
181	#endif
182	goto movefd;
183	case NTOFD:
184	case NFROMFD:
185	if (redir->ndup.dupfd >= 0) { /* if not ">&-" */
186	if (memory[redir->ndup.dupfd])
187	memory[fd] = 1;
188	else
189	copyfd(redir->ndup.dupfd, fd);
190	}
191	break;
192	case NHERE:
193	case NXHERE:
194	f = openhere(redir);
195	goto movefd;
196	default:
197	abort();
198	}
199	INTON;
200	}
201
202
203	/*
204	* Handle here documents. Normally we fork off a process to write the
205	* data to a pipe. If the document is short, we can stuff the data in
206	* the pipe without forking.
207	*/
208
209	STATIC int
210	openhere(redir)
211	union node *redir;
212	{
213	int pip[2];
214	int len;
215
216	if (pipe(pip) < 0)
217	error("Pipe call failed");
218	if (redir->type == NHERE) {
219	len = strlen(redir->nhere.doc->narg.text);
220	if (len <= PIPESIZE) {
221	xwrite(pip[1], redir->nhere.doc->narg.text, len);
222	goto out;
223	}
224	}
225	if (forkshell((struct job )NULL, (union node )NULL, FORK_NOJOB) == 0) {
226	close(pip[0]);
227	signal(SIGINT, SIG_IGN);
228	signal(SIGQUIT, SIG_IGN);
229	signal(SIGHUP, SIG_IGN);
230	#ifdef SIGTSTP
231	signal(SIGTSTP, SIG_IGN);
232	#endif
233	signal(SIGPIPE, SIG_DFL);
234	if (redir->type == NHERE)
235	xwrite(pip[1], redir->nhere.doc->narg.text, len);
236	else
237	expandhere(redir->nhere.doc, pip[1]);
238	_exit(0);
239	}
240	out:
241	close(pip[1]);
242	return pip[0];
243	}
244
245
246
247	/*
248	* Undo the effects of the last redirection.
249	*/
250
251	void
252	popredir() {
253	register struct redirtab *rp = redirlist;
254	int i;
255
256	for (i = 0 ; i < 10 ; i++) {
257	if (rp->renamed[i] != EMPTY) {
258	close(i);
259	if (rp->renamed[i] >= 0) {
260	copyfd(rp->renamed[i], i);
261	close(rp->renamed[i]);
262	}
263	}
264	}
265	INTOFF;
266	redirlist = rp->next;
267	ckfree(rp);
268	INTON;
269	}
270
271
272
273	/*
274	* Undo all redirections. Called on error or interrupt.
275	*/
276
277	#ifdef mkinit
278
279	INCLUDE "redir.h"
280
281	RESET {
282	while (redirlist)
283	popredir();
284	}
285
286	SHELLPROC {
287	clearredir();
288	}
289
290	#endif
291
292
293	/*
294	* Discard all saved file descriptors.
295	*/
296
297	void
298	clearredir() {
299	register struct redirtab *rp;
300	int i;
301
302	for (rp = redirlist ; rp ; rp = rp->next) {
303	for (i = 0 ; i < 10 ; i++) {
304	if (rp->renamed[i] >= 0) {
305	close(rp->renamed[i]);
306	}
307	rp->renamed[i] = EMPTY;
308	}
309	}
310	}
311
312
313
314	/*
315	* Copy a file descriptor, like the F_DUPFD option of fcntl. Returns -1
316	* if the source file descriptor is closed, EMPTY if there are no unused
317	* file descriptors left.
318	*/
319
320	int
321	copyfd(from, to) {
322	#ifdef F_DUPFD
323	int newfd;
324
325	newfd = fcntl(from, F_DUPFD, to);
326	if (newfd < 0 && errno == EMFILE)
327	return EMPTY;
328	return newfd;
329	#else
330	char toclose[32];
331	int i;
332	int newfd;
333	int e;
334
335	for (i = 0 ; i < to ; i++)
336	toclose[i] = 0;
337	INTOFF;
338	while ((newfd = dup(from)) >= 0 && newfd < to)
339	toclose[newfd] = 1;
340	e = errno;
341	for (i = 0 ; i < to ; i++) {
342	if (toclose[i])
343	close(i);
344	}
345	INTON;
346	if (newfd < 0 && e == EMFILE)
347	return EMPTY;
348	return newfd;
349	#endif
350	}