summaryrefslogtreecommitdiffstats
path: root/lib/libutil/gr_util.c
blob: 80d9ee674a2258234dea74ac929fcad781d35e7f (plain)
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
/*-
 * Copyright (c) 2008 Sean C. Farley <scf@FreeBSD.org>
 * 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,
 *    without modification, immediately at the beginning of the file.
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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>
__FBSDID("$FreeBSD$");

#include <sys/param.h>
#include <sys/errno.h>
#include <sys/stat.h>

#include <ctype.h>
#include <err.h>
#include <fcntl.h>
#include <grp.h>
#include <inttypes.h>
#include <libutil.h>
#include <paths.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static int lockfd = -1;
static char group_dir[PATH_MAX];
static char group_file[PATH_MAX];
static char tempname[PATH_MAX];
static int initialized;
static size_t grmemlen(const struct group *, const char *, int *);
static struct group *grcopy(const struct group *gr, char *mem, const char *, int ndx);

/*
 * Initialize statics
 */
int
gr_init(const char *dir, const char *group)
{

	if (dir == NULL) {
		strcpy(group_dir, _PATH_ETC);
	} else {
		if (strlen(dir) >= sizeof(group_dir)) {
			errno = ENAMETOOLONG;
			return (-1);
		}
		strcpy(group_dir, dir);
	}

	if (group == NULL) {
		if (dir == NULL) {
			strcpy(group_file, _PATH_GROUP);
		} else if (snprintf(group_file, sizeof(group_file), "%s/group",
			group_dir) > (int)sizeof(group_file)) {
			errno = ENAMETOOLONG;
			return (-1);
		}
	} else {
		if (strlen(group) >= sizeof(group_file)) {
			errno = ENAMETOOLONG;
			return (-1);
		}
		strcpy(group_file, group);
	}

	initialized = 1;
	return (0);
}

/*
 * Lock the group file
 */
int
gr_lock(void)
{
	if (*group_file == '\0')
		return (-1);

	for (;;) {
		struct stat st;

		lockfd = flopen(group_file, O_RDONLY|O_NONBLOCK|O_CLOEXEC, 0);
		if (lockfd == -1) {
			if (errno == EWOULDBLOCK) {
				errx(1, "the group file is busy");
			} else {
				err(1, "could not lock the group file: ");
			}
		}
		if (fstat(lockfd, &st) == -1)
			err(1, "fstat() failed: ");
		if (st.st_nlink != 0)
			break;
		close(lockfd);
		lockfd = -1;
	}
	return (lockfd);
}

/*
 * Create and open a presmuably safe temp file for editing group data
 */
int
gr_tmp(int mfd)
{
	char buf[8192];
	ssize_t nr;
	const char *p;
	int tfd;

	if (*group_file == '\0')
		return (-1);
	if ((p = strrchr(group_file, '/')))
		++p;
	else
		p = group_file;
	if (snprintf(tempname, sizeof(tempname), "%.*sgroup.XXXXXX",
		(int)(p - group_file), group_file) >= (int)sizeof(tempname)) {
		errno = ENAMETOOLONG;
		return (-1);
	}
	if ((tfd = mkostemp(tempname, O_SYNC)) == -1)
		return (-1);
	if (mfd != -1) {
		while ((nr = read(mfd, buf, sizeof(buf))) > 0)
			if (write(tfd, buf, (size_t)nr) != nr)
				break;
		if (nr != 0) {
			unlink(tempname);
			*tempname = '\0';
			close(tfd);
			return (-1);
		}
	}
	return (tfd);
}

/*
 * Copy the group file from one descriptor to another, replacing, deleting
 * or adding a single record on the way.
 */
int
gr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr)
{
	char buf[8192], *end, *line, *p, *q, *r, t;
	struct group *fgr;
	const struct group *sgr;
	size_t len;
	int eof, readlen;

	if (old_gr == NULL && gr == NULL)
		return(-1);

	sgr = old_gr;
	/* deleting a group */
	if (gr == NULL) {
		line = NULL;
	} else {
		if ((line = gr_make(gr)) == NULL)
			return (-1);
	}

	/* adding a group */
	if (sgr == NULL)
		sgr = gr;

	eof = 0;
	len = 0;
	p = q = end = buf;
	for (;;) {
		/* find the end of the current line */
		for (p = q; q < end && *q != '\0'; ++q)
			if (*q == '\n')
				break;

		/* if we don't have a complete line, fill up the buffer */
		if (q >= end) {
			if (eof)
				break;
			if ((size_t)(q - p) >= sizeof(buf)) {
				warnx("group line too long");
				errno = EINVAL; /* hack */
				goto err;
			}
			if (p < end) {
				q = memmove(buf, p, end -p);
				end -= p - buf;
			} else {
				p = q = end = buf;
			}
			readlen = read(ffd, end, sizeof(buf) - (end -buf));
			if (readlen == -1)
				goto err;
			else
				len = (size_t)readlen;
			if (len == 0 && p == buf)
				break;
			end += len;
			len = end - buf;
			if (len < (ssize_t)sizeof(buf)) {
				eof = 1;
				if (len > 0 && buf[len -1] != '\n')
					++len, *end++ = '\n';
			}
			continue;
		}

		/* is it a blank line or a comment? */
		for (r = p; r < q && isspace(*r); ++r)
			/* nothing */;
		if (r == q || *r == '#') {
			/* yep */
			if (write(tfd, p, q -p + 1) != q - p + 1)
				goto err;
			++q;
			continue;
		}

		/* is it the one we're looking for? */

		t = *q;
		*q = '\0';

		fgr = gr_scan(r);

		/* fgr is either a struct group for the current line,
		 * or NULL if the line is malformed.
		 */

		*q = t;
		if (fgr == NULL || fgr->gr_gid != sgr->gr_gid) {
			/* nope */
			if (fgr != NULL)
				free(fgr);
			if (write(tfd, p, q - p + 1) != q - p + 1)
				goto err;
			++q;
			continue;
		}
		if (old_gr && !gr_equal(fgr, old_gr)) {
			warnx("entry inconsistent");
			free(fgr);
			errno = EINVAL; /* hack */
			goto err;
		}
		free(fgr);

		/* it is, replace or remove it */
		if (line != NULL) {
			len = strlen(line);
			if (write(tfd, line, len) != (int) len)
				goto err;
		} else {
			/* when removed, avoid the \n */
			q++;
		}
		/* we're done, just copy the rest over */
		for (;;) {
			if (write(tfd, q, end - q) != end - q)
				goto err;
			q = buf;
			readlen = read(ffd, buf, sizeof(buf));
			if (readlen == 0)
				break;
			else
				len = (size_t)readlen;
			if (readlen == -1)
				goto err;
			end = buf + len;
		}
		goto done;
	}

	/* if we got here, we didn't find the old entry */
	if (line == NULL) {
		errno = ENOENT;
		goto err;
	}
	len = strlen(line);
	if ((size_t)write(tfd, line, len) != len ||
	   write(tfd, "\n", 1) != 1)
		goto err;
 done:
	if (line != NULL)
		free(line);
	return (0);
 err:
	if (line != NULL)
		free(line);
	return (-1);
}

/*
 * Regenerate the group file
 */
int
gr_mkdb(void)
{
	int fd;

	if (chmod(tempname, 0644) != 0)
		return (-1);

	if (rename(tempname, group_file) != 0)
		return (-1);

	/*
	 * Make sure new group file is safe on disk. To improve performance we
	 * will call fsync() to the directory where file lies
	 */
	if ((fd = open(group_dir, O_RDONLY|O_DIRECTORY)) == -1)
		return (-1);

	if (fsync(fd) != 0) {
		close(fd);
		return (-1);
	}

	close(fd);
	return(0);
}

/*
 * Clean up. Preserves errno for the caller's convenience.
 */
void
gr_fini(void)
{
	int serrno;

	if (!initialized)
		return;
	initialized = 0;
	serrno = errno;
	if (*tempname != '\0') {
		unlink(tempname);
		*tempname = '\0';
	}
	if (lockfd != -1)
		close(lockfd);
	errno = serrno;
}

/*
 * Compares two struct group's.
 */
int
gr_equal(const struct group *gr1, const struct group *gr2)
{
	int gr1_ndx;
	int gr2_ndx;

	/* Check that the non-member information is the same. */
	if (gr1->gr_name == NULL || gr2->gr_name == NULL) {
		if (gr1->gr_name != gr2->gr_name)
			return (false);
	} else if (strcmp(gr1->gr_name, gr2->gr_name) != 0)
		return (false);
	if (gr1->gr_passwd == NULL || gr2->gr_passwd == NULL) {
		if (gr1->gr_passwd != gr2->gr_passwd)
			return (false);
	} else if (strcmp(gr1->gr_passwd, gr2->gr_passwd) != 0)
		return (false);
	if (gr1->gr_gid != gr2->gr_gid)
		return (false);

	/* Check all members in both groups.
	 * getgrnam can return gr_mem with a pointer to NULL.
	 * gr_dup and gr_add strip out this superfluous NULL, setting
	 * gr_mem to NULL for no members.
	*/
	if (gr1->gr_mem != NULL && gr2->gr_mem != NULL) {
		int i;

		for (i = 0; gr1->gr_mem[i] != NULL; i++) {
			if (strcmp(gr1->gr_mem[i], gr2->gr_mem[i]) != 0)
				return (false);
		}
	}
	/* Count number of members in both structs */
	gr2_ndx = 0;
	if (gr2->gr_mem != NULL)
		for(; gr2->gr_mem[gr2_ndx] != NULL; gr2_ndx++)
			/* empty */;
	gr1_ndx = 0;
	if (gr1->gr_mem != NULL)
		for(; gr1->gr_mem[gr1_ndx] != NULL; gr1_ndx++)
			/* empty */;
	if (gr1_ndx != gr2_ndx)
		return (false);

	return (true);
}

/*
 * Make a group line out of a struct group.
 */
char *
gr_make(const struct group *gr)
{
	const char *group_line_format = "%s:%s:%ju:";
	const char *sep;
	char *line;
	char *p;
	size_t line_size;
	int ndx;

	/* Calculate the length of the group line. */
	line_size = snprintf(NULL, 0, group_line_format, gr->gr_name,
	    gr->gr_passwd, (uintmax_t)gr->gr_gid) + 1;
	if (gr->gr_mem != NULL) {
		for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++)
			line_size += strlen(gr->gr_mem[ndx]) + 1;
		if (ndx > 0)
			line_size--;
	}

	/* Create the group line and fill it. */
	if ((line = p = malloc(line_size)) == NULL)
		return (NULL);
	p += sprintf(p, group_line_format, gr->gr_name, gr->gr_passwd,
	    (uintmax_t)gr->gr_gid);
	if (gr->gr_mem != NULL) {
		sep = "";
		for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) {
			p = stpcpy(p, sep);
			p = stpcpy(p, gr->gr_mem[ndx]);
			sep = ",";
		}
	}

	return (line);
}

/*
 * Duplicate a struct group.
 */
struct group *
gr_dup(const struct group *gr)
{
	return (gr_add(gr, NULL));
}
/*
 * Add a new member name to a struct group.
 */
struct group *
gr_add(const struct group *gr, const char *newmember)
{
	char *mem;
	size_t len;
	int num_mem;

	num_mem = 0;
	len = grmemlen(gr, newmember, &num_mem);
	/* Create new group and copy old group into it. */
	if ((mem = malloc(len)) == NULL)
		return (NULL);
	return (grcopy(gr, mem, newmember, num_mem));
}

/* It is safer to walk the pointers given at gr_mem since there is no
 * guarantee the gr_mem + strings are contiguous in the given struct group
 * but compactify the new group into the following form.
 *
 * The new struct is laid out like this in memory. The example given is
 * for a group with two members only.
 *
 * {
 * (char *name)
 * (char *passwd)
 * (int gid)
 * (gr_mem * newgrp + sizeof(struct group) + sizeof(**)) points to gr_mem area
 * gr_mem area
 * (member1 *) 
 * (member2 *)
 * (NULL)
 * (name string)
 * (passwd string)
 * (member1 string)
 * (member2 string)
 * }
 */
/*
 * Copy the contents of a group plus given name to a preallocated group struct
 */
static struct group *
grcopy(const struct group *gr, char *dst, const char *name, int ndx)
{
	int i;
	struct group *newgr;

	newgr = (struct group *)(void *)dst;	/* avoid alignment warning */
	dst += sizeof(*newgr);
	if (ndx != 0) {
		newgr->gr_mem = (char **)(void *)(dst);	/* avoid alignment warning */
		dst += (ndx + 1) * sizeof(*newgr->gr_mem);
	} else
		newgr->gr_mem = NULL;
	if (gr->gr_name != NULL) {
		newgr->gr_name = dst;
		dst = stpcpy(dst, gr->gr_name) + 1;
	} else
		newgr->gr_name = NULL;
	if (gr->gr_passwd != NULL) {
		newgr->gr_passwd = dst;
		dst = stpcpy(dst, gr->gr_passwd) + 1;
	} else
		newgr->gr_passwd = NULL;
	newgr->gr_gid = gr->gr_gid;
	i = 0;
	/* Original group struct might have a NULL gr_mem */
	if (gr->gr_mem != NULL) {
		for (; gr->gr_mem[i] != NULL; i++) {
			newgr->gr_mem[i] = dst;
			dst = stpcpy(dst, gr->gr_mem[i]) + 1;
		}
	}
	/* If name is not NULL, newgr->gr_mem is known to be not NULL */
	if (name != NULL) {
		newgr->gr_mem[i++] = dst;
		dst = stpcpy(dst, name) + 1;
	}
	/* if newgr->gr_mem is not NULL add NULL marker */
	if (newgr->gr_mem != NULL)
		newgr->gr_mem[i] = NULL;

	return (newgr);
}

/*
 *  Calculate length of a struct group + given name
 */
static size_t
grmemlen(const struct group *gr, const char *name, int *num_mem)
{
	size_t len;
	int i;

	if (gr == NULL)
		return (0);
	/* Calculate size of the group. */
	len = sizeof(*gr);
	if (gr->gr_name != NULL)
		len += strlen(gr->gr_name) + 1;
	if (gr->gr_passwd != NULL)
		len += strlen(gr->gr_passwd) + 1;
	i = 0;
	if (gr->gr_mem != NULL) {
		for (; gr->gr_mem[i] != NULL; i++) {
			len += strlen(gr->gr_mem[i]) + 1;
			len += sizeof(*gr->gr_mem);
		}
	}
	if (name != NULL) {
		i++;
		len += strlen(name) + 1;
		len += sizeof(*gr->gr_mem);
	}
	/* Allow for NULL pointer */
	if (i != 0)
		len += sizeof(*gr->gr_mem);
	*num_mem = i;
	return(len);
}

/*
 * Scan a line and place it into a group structure.
 */
static bool
__gr_scan(char *line, struct group *gr)
{
	char *loc;
	int ndx;

	/* Assign non-member information to structure. */
	gr->gr_name = line;
	if ((loc = strchr(line, ':')) == NULL)
		return (false);
	*loc = '\0';
	gr->gr_passwd = loc + 1;
	if (*gr->gr_passwd == ':')
		*gr->gr_passwd = '\0';
	else {
		if ((loc = strchr(loc + 1, ':')) == NULL)
			return (false);
		*loc = '\0';
	}
	if (sscanf(loc + 1, "%u", &gr->gr_gid) != 1)
		return (false);

	/* Assign member information to structure. */
	if ((loc = strchr(loc + 1, ':')) == NULL)
		return (false);
	line = loc + 1;
	gr->gr_mem = NULL;
	ndx = 0;
	do {
		gr->gr_mem = reallocf(gr->gr_mem, sizeof(*gr->gr_mem) *
		    (ndx + 1));
		if (gr->gr_mem == NULL)
			return (false);

		/* Skip locations without members (i.e., empty string). */
		do {
			gr->gr_mem[ndx] = strsep(&line, ",");
		} while (gr->gr_mem[ndx] != NULL && *gr->gr_mem[ndx] == '\0');
	} while (gr->gr_mem[ndx++] != NULL);

	return (true);
}

/*
 * Create a struct group from a line.
 */
struct group *
gr_scan(const char *line)
{
	struct group gr;
	char *line_copy;
	struct group *new_gr;

	if ((line_copy = strdup(line)) == NULL)
		return (NULL);
	if (!__gr_scan(line_copy, &gr)) {
		free(line_copy);
		return (NULL);
	}
	new_gr = gr_dup(&gr);
	free(line_copy);
	if (gr.gr_mem != NULL)
		free(gr.gr_mem);

	return (new_gr);
}
OpenPOWER on IntegriCloud