summary refs log tree commit diff
path: root/src/redir.c
blob: e7bcd500e428143790e02f950a5bf1cc1d94716a (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
/*	$NetBSD: redir.c,v 1.27 2002/11/24 22:35:42 christos Exp $	*/

/*-
 * 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. 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.
 */

#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)redir.c	8.2 (Berkeley) 5/4/95";
#else
__RCSID("$NetBSD: redir.c,v 1.27 2002/11/24 22:35:42 christos Exp $");
#endif
#endif /* not lint */

#include <sys/stat.h>
#include <sys/types.h>
#include <sys/param.h>	/* PIPE_BUF */
#include <signal.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>

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

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


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


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


MKINIT struct redirtab *redirlist;
MKINIT int nullredirs;

STATIC int openredirect(union node *);
#ifdef notyet
STATIC void dupredirect(union node *, int, char[10]);
#else
STATIC void dupredirect(union node *, int);
#endif
STATIC int openhere(union node *);
STATIC int noclobberopen(const char *);


/*
 * 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(union node *redir, int flags)
{
	union node *n;
	struct redirtab *sv;
	int i;
	int fd;
	int newfd;
	int *p;
#if notyet
	char memory[10];	/* file descriptors to write to memory */

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

		newfd = openredirect(n);
		if (fd == newfd)
			continue;
		if (sv && *(p = &sv->renamed[fd]) == EMPTY) {
			int i = fcntl(fd, F_DUPFD, 10);
			if (i == -1) {
				i = errno;
				if (i != EBADF) {
					const char *m = strerror(i);
					close(newfd);
					sh_error("%d: %s", fd, m);
					/* NOTREACHED */
				}
			} else {
				*p = i;
				close(fd);
			}
		} else {
			close(fd);
		}
#ifdef notyet
		dupredirect(n, newfd, memory);
#else
		dupredirect(n, newfd);
#endif
	} while ((n = n->nfile.next));
	INTON;
#ifdef notyet
	if (memory[1])
		out1 = &memout;
	if (memory[2])
		out2 = &memout;
#endif
	if (flags & REDIR_SAVEFD2 && sv && sv->renamed[2] >= 0)
		preverrout.fd = sv->renamed[2];
}


STATIC int
openredirect(union node *redir)
{
	char *fname;
	int f;

	switch (redir->nfile.type) {
	case NFROM:
		fname = redir->nfile.expfname;
		if ((f = open64(fname, O_RDONLY)) < 0)
			goto eopen;
		break;
	case NFROMTO:
		fname = redir->nfile.expfname;
		if ((f = open64(fname, O_RDWR|O_CREAT|O_TRUNC, 0666)) < 0)
			goto ecreate;
		break;
	case NTO:
		/* Take care of noclobber mode. */
		if (Cflag) {
			fname = redir->nfile.expfname;
			if ((f = noclobberopen(fname)) < 0)
				goto ecreate;
			break;
		}
		/* FALLTHROUGH */
	case NCLOBBER:
		fname = redir->nfile.expfname;
		if ((f = open64(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0)
			goto ecreate;
		break;
	case NAPPEND:
		fname = redir->nfile.expfname;
		if ((f = open64(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0)
			goto ecreate;
		break;
	default:
#ifdef DEBUG
		abort();
#endif
		/* Fall through to eliminate warning. */
	case NTOFD:
	case NFROMFD:
		f = -1;
		break;
	case NHERE:
	case NXHERE:
		f = openhere(redir);
		break;
	}

	return f;
ecreate:
	sh_error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
eopen:
	sh_error("cannot open %s: %s", fname, errmsg(errno, E_OPEN));
}


STATIC void
#ifdef notyet
dupredirect(redir, f, memory)
#else
dupredirect(redir, f)
#endif
	union node *redir;
	int f;
#ifdef notyet
	char memory[10];
#endif
	{
	int fd = redir->nfile.fd;

#ifdef notyet
	memory[fd] = 0;
#endif
	if (redir->nfile.type == NTOFD || redir->nfile.type == NFROMFD) {
		if (redir->ndup.dupfd >= 0) {	/* if not ">&-" */
#ifdef notyet
			if (memory[redir->ndup.dupfd])
				memory[fd] = 1;
			else
#endif
				copyfd(redir->ndup.dupfd, fd);
		}
		return;
	}

	if (f != fd) {
		copyfd(f, fd);
		close(f);
	}
	return;
}


/*
 * 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)
{
	int pip[2];
	size_t len = 0;

	if (pipe(pip) < 0)
		sh_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(int drop)
{
	struct redirtab *rp;
	int i;

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

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

#ifdef mkinit

INCLUDE "redir.h"

RESET {
	clearredir(0);
}

#endif

/*
 * Discard all saved file descriptors.
 */

void
clearredir(int drop)
{
	for (;;) {
		nullredirs = 0;
		if (!redirlist)
			break;
		popredir(drop);
	}
}



/*
 * Copy a file descriptor to be >= to.  Returns -1
 * if the source file descriptor is closed, EMPTY if there are no unused
 * file descriptors left.
 */

int
copyfd(int from, int to)
{
	int newfd;

	newfd = fcntl(from, F_DUPFD, to);
	if (newfd < 0) {
		int errno2 = errno;
		if (errno2 == EMFILE)
			return EMPTY;
		else
			sh_error("%d: %s", from, strerror(errno2));
	}
	return newfd;
}


/*
 * Open a file in noclobber mode.
 * The code was copied from bash.
 */
int
noclobberopen(fname)
	const char *fname;
{
	int r, fd;
	struct stat64 finfo, finfo2;

	/*
	 * If the file exists and is a regular file, return an error
	 * immediately.
	 */
	r = stat64(fname, &finfo);
	if (r == 0 && S_ISREG(finfo.st_mode)) {
		errno = EEXIST;
		return -1;
	}

	/*
	 * If the file was not present (r != 0), make sure we open it
	 * exclusively so that if it is created before we open it, our open
	 * will fail.  Make sure that we do not truncate an existing file.
	 * Note that we don't turn on O_EXCL unless the stat failed -- if the
	 * file was not a regular file, we leave O_EXCL off.
	 */
	if (r != 0)
		return open64(fname, O_WRONLY|O_CREAT|O_EXCL, 0666);
	fd = open64(fname, O_WRONLY|O_CREAT, 0666);

	/* If the open failed, return the file descriptor right away. */
	if (fd < 0)
		return fd;

	/*
	 * OK, the open succeeded, but the file may have been changed from a
	 * non-regular file to a regular file between the stat and the open.
	 * We are assuming that the O_EXCL open handles the case where FILENAME
	 * did not exist and is symlinked to an existing file between the stat
	 * and open.
	 */

	/*
	 * If we can open it and fstat the file descriptor, and neither check
	 * revealed that it was a regular file, and the file has not been
	 * replaced, return the file descriptor.
	 */
	 if (fstat64(fd, &finfo2) == 0 && !S_ISREG(finfo2.st_mode) &&
	     finfo.st_dev == finfo2.st_dev && finfo.st_ino == finfo2.st_ino)
	 	return fd;

	/* The file has been replaced.  badness. */
	close(fd);
	errno = EEXIST;
	return -1;
}


int
redirectsafe(union node *redir, int flags)
{
	int err;
	volatile int saveint;
	struct jmploc *volatile savehandler = handler;
	struct jmploc jmploc;

	SAVEINT(saveint);
	if (!(err = setjmp(jmploc.loc) * 2)) {
		handler = &jmploc;
		redirect(redir, flags);
	}
	handler = savehandler;
	if (err && exception != EXERROR)
		longjmp(handler->loc, 1);
	RESTOREINT(saveint);
	return err;
}