File: popen.c

package info (click to toggle)
heirloom-mailx 12.4-2
  • links: PTS
  • area: main
  • in suites: squeeze
  • size: 1,524 kB
  • ctags: 1,960
  • sloc: ansic: 29,443; sh: 333; makefile: 126
file content (695 lines) | stat: -rw-r--r-- 15,555 bytes parent folder | download | duplicates (6)
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
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
/*
 * Heirloom mailx - a mail user agent derived from Berkeley Mail.
 *
 * Copyright (c) 2000-2004 Gunnar Ritter, Freiburg i. Br., Germany.
 */
/*
 * Copyright (c) 1980, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * 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
#ifdef	DOSCCS
static char sccsid[] = "@(#)popen.c	2.20 (gritter) 3/4/06";
#endif
#endif /* not lint */

#include "rcv.h"
#include "extern.h"
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/wait.h>
#include <errno.h>

#ifndef	NSIG
#define	NSIG	32
#endif

#define READ 0
#define WRITE 1

struct fp {
	FILE *fp;
	struct fp *link;
	char *realfile;
	long offset;
	int omode;
	int pipe;
	int pid;
	enum {
		FP_UNCOMPRESSED	= 00,
		FP_GZIPPED	= 01,
		FP_BZIP2ED	= 02,
		FP_IMAP		= 03,
		FP_MAILDIR	= 04,
		FP_MASK		= 0177,
		FP_READONLY	= 0200
	} compressed;
};
static struct fp *fp_head;

struct child {
	int pid;
	char done;
	char free;
	int status;
	struct child *link;
};
static struct child	*child;

static int scan_mode(const char *mode, int *omode);
static void register_file(FILE *fp, int omode, int pipe, int pid,
		int compressed, const char *realfile, long offset);
static enum okay compress(struct fp *fpp);
static int decompress(int compression, int input, int output);
static enum okay unregister_file(FILE *fp);
static int file_pid(FILE *fp);
static int wait_command(int pid);
static struct child *findchild(int pid);
static void delchild(struct child *cp);

/*
 * Provide BSD-like signal() on all systems.
 */
sighandler_type
safe_signal(int signum, sighandler_type handler)
{
	struct sigaction nact, oact;

	nact.sa_handler = handler;
	sigemptyset(&nact.sa_mask);
	nact.sa_flags = 0;
#ifdef	SA_RESTART
	nact.sa_flags |= SA_RESTART;
#endif
	if (sigaction(signum, &nact, &oact) != 0)
		return SIG_ERR;
	return oact.sa_handler;
}

static int 
scan_mode(const char *mode, int *omode)
{

	if (!strcmp(mode, "r")) {
		*omode = O_RDONLY;
	} else if (!strcmp(mode, "w")) {
		*omode = O_WRONLY | O_CREAT | O_TRUNC;
	} else if (!strcmp(mode, "wx")) {
		*omode = O_WRONLY | O_CREAT | O_EXCL;
	} else if (!strcmp(mode, "a")) {
		*omode = O_WRONLY | O_APPEND | O_CREAT;
	} else if (!strcmp(mode, "a+")) {
		*omode = O_RDWR | O_APPEND;
	} else if (!strcmp(mode, "r+")) {
		*omode = O_RDWR;
	} else if (!strcmp(mode, "w+")) {
		*omode = O_RDWR   | O_CREAT | O_EXCL;
	} else {
		fprintf(stderr, catgets(catd, CATSET, 152,
			"Internal error: bad stdio open mode %s\n"), mode);
		errno = EINVAL;
		return -1;
	}
	return 0;
}

FILE *
safe_fopen(const char *file, const char *mode, int *omode)
{
	int  fd;

	if (scan_mode(mode, omode) < 0) 
		return NULL;
	if ((fd = open(file, *omode, 0666)) < 0)
		return NULL;
	return fdopen(fd, mode);
}

FILE *
Fopen(const char *file, const char *mode)
{
	FILE *fp;
	int omode;

	if ((fp = safe_fopen(file, mode, &omode)) != NULL) {
		register_file(fp, omode, 0, 0, FP_UNCOMPRESSED, NULL, 0L);
		fcntl(fileno(fp), F_SETFD, FD_CLOEXEC);
	}
	return fp;
}

FILE *
Fdopen(int fd, const char *mode)
{
	FILE *fp;
	int	omode;

	scan_mode(mode, &omode);
	if ((fp = fdopen(fd, mode)) != NULL) {
		register_file(fp, omode, 0, 0, FP_UNCOMPRESSED, NULL, 0L);
		fcntl(fileno(fp), F_SETFD, FD_CLOEXEC);
	}
	return fp;
}

int
Fclose(FILE *fp)
{
	int	i = 0;
	if (unregister_file(fp) == OKAY)
		i |= 1;
	if (fclose(fp) == 0)
		i |= 2;
	return i == 3 ? 0 : EOF;
}

FILE *
Zopen(const char *file, const char *mode, int *compression)
{
	int	input;
	FILE	*output;
	const char	*rp;
	int	omode;
	char	*tempfn;
	int	bits;
	int	_compression;
	long	offset;
	char	*extension;
	enum protocol	p;

	if (scan_mode(mode, &omode) < 0)
		return NULL;
	if (compression == NULL)
		compression = &_compression;
	bits = R_OK | (omode == O_RDONLY ? 0 : W_OK);
	if (omode & O_APPEND && ((p = which_protocol(file)) == PROTO_IMAP ||
			p == PROTO_MAILDIR)) {
		*compression = p == PROTO_IMAP ? FP_IMAP : FP_MAILDIR;
		omode = O_RDWR | O_APPEND | O_CREAT;
		rp = file;
		input = -1;
		goto open;
	}
	if ((extension = strrchr(file, '.')) != NULL) {
		rp = file;
		if (strcmp(extension, ".gz") == 0)
			goto gzip;
		if (strcmp(extension, ".bz2") == 0)
			goto bz2;
	}
	if (access(file, F_OK) == 0) {
		*compression = FP_UNCOMPRESSED;
		return Fopen(file, mode);
	} else if (access(rp=savecat(file, ".gz"), bits) == 0) {
	gzip:	*compression = FP_GZIPPED;
	} else if (access(rp=savecat(file, ".bz2"), bits) == 0) {
	bz2:	*compression = FP_BZIP2ED;
	} else {
		*compression = FP_UNCOMPRESSED;
		return Fopen(file, mode);
	}
	if (access(rp, W_OK) < 0)
		*compression |= FP_READONLY;
	if ((input = open(rp, bits & W_OK ? O_RDWR : O_RDONLY)) < 0
			&& ((omode&O_CREAT) == 0 || errno != ENOENT))
		return NULL;
open:	if ((output = Ftemp(&tempfn, "Rz", "w+", 0600, 0)) == NULL) {
		perror(catgets(catd, CATSET, 167, "tmpfile"));
		close(input);
		return NULL;
	}
	unlink(tempfn);
	if (input >= 0 || (*compression&FP_MASK) == FP_IMAP ||
			(*compression&FP_MASK) == FP_MAILDIR) {
		if (decompress(*compression, input, fileno(output)) < 0) {
			close(input);
			Fclose(output);
			return NULL;
		}
	} else {
		if ((input = creat(rp, 0666)) < 0) {
			Fclose(output);
			return NULL;
		}
	}
	close(input);
	fflush(output);
	if (omode & O_APPEND) {
		int	flags;

		if ((flags = fcntl(fileno(output), F_GETFL)) != -1)
			fcntl(fileno(output), F_SETFL, flags | O_APPEND);
		offset = ftell(output);
	} else {
		rewind(output);
		offset = 0;
	}
	register_file(output, omode, 0, 0, *compression, rp, offset);
	return output;
}

FILE *
Popen(const char *cmd, const char *mode, const char *shell, int newfd1)
{
	int p[2];
	int myside, hisside, fd0, fd1;
	int pid;
	char mod[2] = { '0', '\0' };
	sigset_t nset;
	FILE *fp;

	if (pipe(p) < 0)
		return NULL;
	fcntl(p[READ], F_SETFD, FD_CLOEXEC);
	fcntl(p[WRITE], F_SETFD, FD_CLOEXEC);
	if (*mode == 'r') {
		myside = p[READ];
		fd0 = -1;
		hisside = fd1 = p[WRITE];
		mod[0] = *mode;
	} else if (*mode == 'W') {
		myside = p[WRITE];
		hisside = fd0 = p[READ];
		fd1 = newfd1;
		mod[0] = 'w';
	} else {
		myside = p[WRITE];
		hisside = fd0 = p[READ];
		fd1 = -1;
		mod[0] = 'w';
	}
	sigemptyset(&nset);
	if (shell == NULL) {
		pid = start_command(cmd, &nset, fd0, fd1, NULL, NULL, NULL);
	} else {
		pid = start_command(shell, &nset, fd0, fd1, "-c", cmd, NULL);
	}
	if (pid < 0) {
		close(p[READ]);
		close(p[WRITE]);
		return NULL;
	}
	close(hisside);
	if ((fp = fdopen(myside, mod)) != NULL)
		register_file(fp, 0, 1, pid, FP_UNCOMPRESSED, NULL, 0L);
	return fp;
}

int
Pclose(FILE *ptr)
{
	int i;
	sigset_t nset, oset;

	i = file_pid(ptr);
	if (i < 0)
		return 0;
	unregister_file(ptr);
	fclose(ptr);
	sigemptyset(&nset);
	sigaddset(&nset, SIGINT);
	sigaddset(&nset, SIGHUP);
	sigprocmask(SIG_BLOCK, &nset, &oset);
	i = wait_child(i);
	sigprocmask(SIG_SETMASK, &oset, (sigset_t *)NULL);
	return i;
}

void 
close_all_files(void)
{

	while (fp_head)
		if (fp_head->pipe)
			Pclose(fp_head->fp);
		else
			Fclose(fp_head->fp);
}

static void
register_file(FILE *fp, int omode, int pipe, int pid, int compressed,
		const char *realfile, long offset)
{
	struct fp *fpp;

	fpp = (struct fp*)smalloc(sizeof *fpp);
	fpp->fp = fp;
	fpp->omode = omode;
	fpp->pipe = pipe;
	fpp->pid = pid;
	fpp->link = fp_head;
	fpp->compressed = compressed;
	fpp->realfile = realfile ? sstrdup(realfile) : NULL;
	fpp->offset = offset;
	fp_head = fpp;
}

static enum okay
compress(struct fp *fpp)
{
	int	output;
	char	*command[2];
	enum okay	ok;

	if (fpp->omode == O_RDONLY)
		return OKAY;
	fflush(fpp->fp);
	clearerr(fpp->fp);
	fseek(fpp->fp, fpp->offset, SEEK_SET);
	if ((fpp->compressed&FP_MASK) == FP_IMAP) {
		return imap_append(fpp->realfile, fpp->fp);
	}
	if ((fpp->compressed&FP_MASK) == FP_MAILDIR) {
		return maildir_append(fpp->realfile, fpp->fp);
	}
	if ((output = open(fpp->realfile,
			(fpp->omode|O_CREAT)&~O_EXCL,
			0666)) < 0) {
		fprintf(stderr, "Fatal: cannot create ");
		perror(fpp->realfile);
		return STOP;
	}
	if ((fpp->omode & O_APPEND) == 0)
		ftruncate(output, 0);
	switch (fpp->compressed & FP_MASK) {
	case FP_GZIPPED:
		command[0] = "gzip"; command[1] = "-c"; break;
	case FP_BZIP2ED:
		command[0] = "bzip2"; command[1] = "-c"; break;
	default:
		command[0] = "cat"; command[1] = NULL; break;
	}
	if (run_command(command[0], 0, fileno(fpp->fp), output,
				command[1], NULL, NULL) < 0)
		ok = STOP;
	else
		ok = OKAY;
	close(output);
	return ok;
}

static int
decompress(int compression, int input, int output)
{
	char	*command[2];

	/*
	 * Note that it is not possible to handle 'pack' or 'compress'
	 * formats because appending data does not work with them.
	 */
	switch (compression & FP_MASK) {
	case FP_GZIPPED:	command[0] = "gzip"; command[1] = "-cd"; break;
	case FP_BZIP2ED:	command[0] = "bzip2"; command[1] = "-cd"; break;
	case FP_IMAP:		return 0;
	case FP_MAILDIR:	return 0;
	default:		command[0] = "cat"; command[1] = NULL;
	}
	return run_command(command[0], 0, input, output,
			command[1], NULL, NULL);
}

static enum okay
unregister_file(FILE *fp)
{
	struct fp **pp, *p;
	enum okay	ok = OKAY;

	for (pp = &fp_head; (p = *pp) != (struct fp *)NULL; pp = &p->link)
		if (p->fp == fp) {
			if ((p->compressed&FP_MASK) != FP_UNCOMPRESSED)
				ok = compress(p);
			*pp = p->link;
			free(p);
			return ok;
		}
	panic(catgets(catd, CATSET, 153, "Invalid file pointer"));
	/*NOTREACHED*/
	return STOP;
}

static int
file_pid(FILE *fp)
{
	struct fp *p;

	for (p = fp_head; p; p = p->link)
		if (p->fp == fp)
			return (p->pid);
	return -1;
}

/*
 * Run a command without a shell, with optional arguments and splicing
 * of stdin and stdout.  The command name can be a sequence of words.
 * Signals must be handled by the caller.
 * "Mask" contains the signals to ignore in the new process.
 * SIGINT is enabled unless it's in the mask.
 */
/*VARARGS4*/
int
run_command(char *cmd, sigset_t *mask, int infd, int outfd,
		char *a0, char *a1, char *a2)
{
	int pid;

	if ((pid = start_command(cmd, mask, infd, outfd, a0, a1, a2)) < 0)
		return -1;
	return wait_command(pid);
}

/*VARARGS4*/
int
start_command(const char *cmd, sigset_t *mask, int infd, int outfd,
		const char *a0, const char *a1, const char *a2)
{
	int pid;

	if ((pid = fork()) < 0) {
		perror("fork");
		return -1;
	}
	if (pid == 0) {
		char *argv[100];
		int i = getrawlist(cmd, strlen(cmd),
				argv, sizeof argv / sizeof *argv, 0);

		if ((argv[i++] = (char *)a0) != NULL &&
		    (argv[i++] = (char *)a1) != NULL &&
		    (argv[i++] = (char *)a2) != NULL)
			argv[i] = NULL;
		prepare_child(mask, infd, outfd);
		execvp(argv[0], argv);
		perror(argv[0]);
		_exit(1);
	}
	return pid;
}

void
prepare_child(sigset_t *nset, int infd, int outfd)
{
	int i;
	sigset_t fset;

	/*
	 * All file descriptors other than 0, 1, and 2 are supposed to be
	 * close-on-exec.
	 */
	if (infd >= 0)
		dup2(infd, 0);
	if (outfd >= 0)
		dup2(outfd, 1);
	if (nset) {
		for (i = 1; i < NSIG; i++)
			if (sigismember(nset, i))
				safe_signal(i, SIG_IGN);
		if (!sigismember(nset, SIGINT))
			safe_signal(SIGINT, SIG_DFL);
	}
	sigfillset(&fset);
	sigprocmask(SIG_UNBLOCK, &fset, (sigset_t *)NULL);
}

static int 
wait_command(int pid)
{

	if (wait_child(pid) < 0 && (value("bsdcompat") || value("bsdmsgs"))) {
		printf(catgets(catd, CATSET, 154, "Fatal error in process.\n"));
		return -1;
	}
	return 0;
}

static struct child *
findchild(int pid)
{
	struct child **cpp;

	for (cpp = &child; *cpp != (struct child *)NULL && (*cpp)->pid != pid;
	     cpp = &(*cpp)->link)
			;
	if (*cpp == (struct child *)NULL) {
		*cpp = (struct child *) smalloc(sizeof (struct child));
		(*cpp)->pid = pid;
		(*cpp)->done = (*cpp)->free = 0;
		(*cpp)->link = (struct child *)NULL;
	}
	return *cpp;
}

static void 
delchild(struct child *cp)
{
	struct child **cpp;

	for (cpp = &child; *cpp != cp; cpp = &(*cpp)->link)
		;
	*cpp = cp->link;
	free(cp);
}

/*ARGSUSED*/
void 
sigchild(int signo)
{
	int pid;
	int status;
	struct child *cp;

again:
	while ((pid = waitpid(-1, (int*)&status, WNOHANG)) > 0) {
		cp = findchild(pid);
		if (cp->free)
			delchild(cp);
		else {
			cp->done = 1;
			cp->status = status;
		}
	}
	if (pid == -1 && errno == EINTR)
		goto again;
}

int wait_status;

/*
 * Mark a child as don't care.
 */
void 
free_child(int pid)
{
	sigset_t nset, oset;
	struct child *cp = findchild(pid);
	sigemptyset(&nset);
	sigaddset(&nset, SIGCHLD);
	sigprocmask(SIG_BLOCK, &nset, &oset);

	if (cp->done)
		delchild(cp);
	else
		cp->free = 1;
	sigprocmask(SIG_SETMASK, &oset, (sigset_t *)NULL);
}

/*
 * Wait for a specific child to die.
 */
#if 0
/*
 * This version is correct code, but causes harm on some loosing
 * systems. So we use the second one instead.
 */
int 
wait_child(int pid)
{
	sigset_t nset, oset;
	struct child *cp = findchild(pid);
	sigemptyset(&nset);
	sigaddset(&nset, SIGCHLD);
	sigprocmask(SIG_BLOCK, &nset, &oset);

	while (!cp->done)
		sigsuspend(&oset);
	wait_status = cp->status;
	delchild(cp);
	sigprocmask(SIG_SETMASK, &oset, (sigset_t *)NULL);

	if (WIFEXITED(wait_status) && (WEXITSTATUS(wait_status) == 0))
		return 0;
	return -1;
}
#endif
int 
wait_child(int pid)
{
	pid_t term;
	struct child *cp;
	struct sigaction nact, oact;
	
	nact.sa_handler = SIG_DFL;
	sigemptyset(&nact.sa_mask);
	nact.sa_flags = SA_NOCLDSTOP;
	sigaction(SIGCHLD, &nact, &oact);
	
	cp = findchild(pid);
	if (!cp->done) {
		do {
			term = wait(&wait_status);
			if (term == -1 && errno == EINTR)
				continue;
			if (term == 0 || term == -1)
				break;
			cp = findchild(term);
			if (cp->free || term == pid) {
				delchild(cp);
			} else {
				cp->done = 1;
				cp->status = wait_status;
			}
		} while (term != pid);
	} else {
		wait_status = cp->status;
		delchild(cp);
	}
	
	sigaction(SIGCHLD, &oact, NULL);
	/*
	 * Make sure no zombies are left.
	 */
	sigchild(SIGCHLD);
	
	if (WIFEXITED(wait_status) && (WEXITSTATUS(wait_status) == 0))
		return 0;
	return -1;
}