summaryrefslogtreecommitdiffstats
path: root/mdopen.c
blob: d3022a548b4b75b11d73eacab16aae2120dcaa6a (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
/*
 * mdadm - manage Linux "md" devices aka RAID arrays.
 *
 * Copyright (C) 2001-2013 Neil Brown <neilb@suse.de>
 *
 *
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *    Author: Neil Brown
 *    Email: <neilb@suse.de>
 */

#include "mdadm.h"
#include "md_p.h"
#include <ctype.h>

void make_parts(char *dev, int cnt)
{
	/* make 'cnt' partition devices for 'dev'
	 * If dev is a device name we use the
	 *  major/minor from dev and add 1..cnt
	 * If it is a symlink, we make similar symlinks.
	 * If dev ends with a digit, we add "p%d" else "%d"
	 * If the name exists, we use it's owner/mode,
	 * else that of dev
	 */
	struct stat stb;
	int major_num;
	int minor_num;
	int odig;
	int i;
	int nlen = strlen(dev) + 20;
	char *name;
	int dig = isdigit(dev[strlen(dev)-1]);
	char orig[1001];
	char sym[1024];
	int err;

	if (cnt == 0)
		cnt = 4;
	if (lstat(dev, &stb)!= 0)
		return;

	if (S_ISBLK(stb.st_mode)) {
		major_num = major(stb.st_rdev);
		minor_num = minor(stb.st_rdev);
		odig = -1;
	} else if (S_ISLNK(stb.st_mode)) {
		int len;

		len = readlink(dev, orig, sizeof(orig));
		if (len < 0 || len >= (int)sizeof(orig))
			return;
		orig[len] = 0;
		odig = isdigit(orig[len-1]);
		major_num = -1;
		minor_num = -1;
	} else
		return;
	name = xmalloc(nlen);
	for (i = 1; i <= cnt ; i++) {
		struct stat stb2;
		snprintf(name, nlen, "%s%s%d", dev, dig?"p":"", i);
		if (stat(name, &stb2) == 0) {
			if (!S_ISBLK(stb2.st_mode) || !S_ISBLK(stb.st_mode))
				continue;
			if (stb2.st_rdev == makedev(major_num, minor_num+i))
				continue;
			unlink(name);
		} else {
			stb2 = stb;
		}
		if (S_ISBLK(stb.st_mode)) {
			if (mknod(name, S_IFBLK | 0600,
				  makedev(major_num, minor_num+i)))
				perror("mknod");
			if (chown(name, stb2.st_uid, stb2.st_gid))
				perror("chown");
			if (chmod(name, stb2.st_mode & 07777))
				perror("chmod");
			err = 0;
		} else {
			snprintf(sym, sizeof(sym), "%s%s%d", orig, odig?"p":"", i);
			err = symlink(sym, name);
		}

		if (err == 0 && stat(name, &stb2) == 0)
			add_dev(name, &stb2, 0, NULL);
	}
	free(name);
}

int create_named_array(char *devnm)
{
	int fd;
	int n = -1;
	static const char new_array_file[] = {
		"/sys/module/md_mod/parameters/new_array"
	};

	fd = open(new_array_file, O_WRONLY);
	if (fd < 0 && errno == ENOENT) {
		if (system("modprobe md_mod") == 0)
			fd = open(new_array_file, O_WRONLY);
	}
	if (fd >= 0) {
		n = write(fd, devnm, strlen(devnm));
		close(fd);
	}
	if (fd < 0 || n != (int)strlen(devnm)) {
		pr_err("Fail to create %s when using %s, fallback to creation via node\n",
			devnm, new_array_file);
		return 0;
	}

	return 1;
}

/*
 * We need a new md device to assemble/build/create an array.
 * 'dev' is a name given us by the user (command line or mdadm.conf)
 * It might start with /dev or /dev/md any might end with a digit
 * string.
 * If it starts with just /dev, it must be /dev/mdX or /dev/md_dX
 * If it ends with a digit string, then it must be as above, or
 * 'trustworthy' must be 'METADATA' and the 'dev' must be
 *  /dev/md/'name'NN or 'name'NN
 * If it doesn't end with a digit string, it must be /dev/md/'name'
 * or 'name' or must be NULL.
 * If the digit string is present, it gives the minor number to use
 * If not, we choose a high, unused minor number.
 * If the 'dev' is a standard name, it devices whether 'md' or 'mdp'.
 * else if the name is 'd[0-9]+' then we use mdp
 * else if trustworthy is 'METADATA' we use md
 * else the choice depends on 'autof'.
 * If name is NULL it is assumed to match whatever dev provides.
 * If both name and dev are NULL, we choose a name 'mdXX' or 'mdpXX'
 *
 * If 'name' is given, and 'trustworthy' is 'foreign' and name is not
 * supported by 'dev', we add a "_%d" suffix based on the minor number
 * use that.
 *
 * If udev is configured, we create a temporary device, open it, and
 * unlink it.
 * If not, we create the /dev/mdXX device, and if name is usable,
 * /dev/md/name
 * In any case we return /dev/md/name or (if that isn't available)
 * /dev/mdXX in 'chosen'.
 *
 * When we create devices, we use uid/gid/umask from config file.
 */

int create_mddev(char *dev, char *name, int autof, int trustworthy,
		 char *chosen, int block_udev)
{
	int mdfd;
	struct stat stb;
	int num = -1;
	int use_mdp = -1;
	struct createinfo *ci = conf_get_create_info();
	int parts;
	char *cname;
	char devname[37];
	char devnm[32];
	char cbuf[400];

	if (!use_udev())
		block_udev = 0;

	if (chosen == NULL)
		chosen = cbuf;

	if (autof == 0)
		autof = ci->autof;

	parts = autof >> 3;
	autof &= 7;

	strcpy(chosen, DEV_MD_DIR);
	cname = chosen + strlen(chosen);

	if (dev) {
		if (strncmp(dev, DEV_MD_DIR, DEV_MD_DIR_LEN) == 0) {
			strcpy(cname, dev + DEV_MD_DIR_LEN);
		} else if (strncmp(dev, "/dev/", 5) == 0) {
			char *e = dev + strlen(dev);
			while (e > dev && isdigit(e[-1]))
				e--;
			if (e[0])
				num = strtoul(e, NULL, 10);
			strcpy(cname, dev+5);
			cname[e-(dev+5)] = 0;
			/* name *must* be mdXX or md_dXX in this context */
			if (num < 0 ||
			    (strcmp(cname, "md") != 0 && strcmp(cname, "md_d") != 0)) {
				pr_err("%s is an invalid name for an md device.  Try /dev/md/%s\n",
					dev, dev+5);
				return -1;
			}
			if (strcmp(cname, "md") == 0)
				use_mdp = 0;
			else
				use_mdp = 1;
			/* recreate name: /dev/md/0 or /dev/md/d0 */
			sprintf(cname, "%s%d", use_mdp?"d":"", num);
		} else
			strcpy(cname, dev);

		/* 'cname' must not contain a slash, and may not be
		 * empty.
		 */
		if (strchr(cname, '/') != NULL) {
			pr_err("%s is an invalid name for an md device.\n", dev);
			return -1;
		}
		if (cname[0] == 0) {
			pr_err("%s is an invalid name for an md device (empty!).\n", dev);
			return -1;
		}
		if (num < 0) {
			/* If cname  is 'N' or 'dN', we get dev number
			 * from there.
			 */
			char *sp = cname;
			char *ep;
			if (cname[0] == 'd')
				sp++;
			if (isdigit(sp[0]))
				num = strtoul(sp, &ep, 10);
			else
				ep = sp;
			if (ep == sp || *ep || num < 0)
				num = -1;
			else if (cname[0] == 'd')
				use_mdp = 1;
			else
				use_mdp = 0;
		}
	}

	/* Now determine device number */
	/* named 'METADATA' cannot use 'mdp'. */
	if (name && name[0] == 0)
		name = NULL;
	if (name && trustworthy == METADATA && use_mdp == 1) {
		pr_err("%s is not allowed for a %s container. Consider /dev/md%d.\n", dev, name, num);
		return -1;
	}
	if (name && trustworthy == METADATA)
		use_mdp = 0;
	if (use_mdp == -1) {
		if (autof == 4 || autof == 6)
			use_mdp = 1;
		else
			use_mdp = 0;
	}
	if (num < 0 && trustworthy == LOCAL && name) {
		/* if name is numeric, possibly prefixed by
		 * 'md' or '/dev/md', use that for num
		 * if it is not already in use */
		char *ep;
		char *n2 = name;
		if (strncmp(n2, "/dev/", 5) == 0)
			n2 += 5;
		if (strncmp(n2, "md", 2) == 0)
			n2 += 2;
		if (*n2 == '/')
			n2++;
		num = strtoul(n2, &ep, 10);
		if (ep == n2 || *ep)
			num = -1;
		else {
			sprintf(devnm, "md%s%d", use_mdp ? "_d":"", num);
			if (mddev_busy(devnm))
				num = -1;
		}
	}

	if (cname[0] == 0 && name) {
		/* Need to find a name if we can
		 * We don't completely trust 'name'.  Truncate to
		 * reasonable length and remove '/'
		 */
		char *cp;
		struct map_ent *map = NULL;
		int conflict = 1;
		int unum = 0;
		int cnlen;
		strncpy(cname, name, 200);
		cname[200] = 0;
		for (cp = cname; *cp ; cp++)
			switch (*cp) {
			case '/':
				*cp = '-';
				break;
			case ' ':
			case '\t':
				*cp = '_';
				break;
			}

		if (trustworthy == LOCAL ||
		    (trustworthy == FOREIGN && strchr(cname, ':') != NULL)) {
			/* Only need suffix if there is a conflict */
			if (map_by_name(&map, cname) == NULL)
				conflict = 0;
		}
		cnlen = strlen(cname);
		while (conflict) {
			if (trustworthy == METADATA && !isdigit(cname[cnlen-1]))
				sprintf(cname+cnlen, "%d", unum);
			else
				/* add _%d to FOREIGN array that don't
				 * a 'host:' prefix
				 */
				sprintf(cname+cnlen, "_%d", unum);
			unum++;
			if (map_by_name(&map, cname) == NULL)
				conflict = 0;
		}
	}

	devnm[0] = 0;
	if (num < 0 && cname && ci->names) {
		sprintf(devnm, "md_%s", cname);
		if (block_udev)
			udev_block(devnm);
		if (!create_named_array(devnm)) {
			devnm[0] = 0;
			udev_unblock();
		}
	}
	if (num >= 0) {
		sprintf(devnm, "md%d", num);
		if (block_udev)
			udev_block(devnm);
		if (!create_named_array(devnm)) {
			devnm[0] = 0;
			udev_unblock();
		}
	}
	if (devnm[0] == 0) {
		if (num < 0) {
			/* need to choose a free number. */
			char *_devnm = find_free_devnm(use_mdp);
			if (_devnm == NULL) {
				pr_err("No avail md devices - aborting\n");
				return -1;
			}
			strcpy(devnm, _devnm);
		} else {
			sprintf(devnm, "%s%d", use_mdp?"md_d":"md", num);
			if (mddev_busy(devnm)) {
				pr_err("%s is already in use.\n",
				       dev);
				return -1;
			}
		}
		if (block_udev)
			udev_block(devnm);
		create_named_array(devnm);
	}

	sprintf(devname, "/dev/%s", devnm);

	if (dev && dev[0] == '/')
		strcpy(chosen, dev);
	else if (cname[0] == 0)
		strcpy(chosen, devname);

	/* We have a device number and name.
	 * If we cannot detect udev, we need to make
	 * devices and links ourselves.
	 */
	if (!use_udev()) {
		/* Make sure 'devname' exists and 'chosen' is a symlink to it */
		if (lstat(devname, &stb) == 0) {
			/* Must be the correct device, else error */
			if ((stb.st_mode&S_IFMT) != S_IFBLK ||
			    stb.st_rdev != devnm2devid(devnm)) {
				pr_err("%s exists but looks wrong, please fix\n",
					devname);
				return -1;
			}
		} else {
			if (mknod(devname, S_IFBLK|0600,
				  devnm2devid(devnm)) != 0) {
				pr_err("failed to create %s\n",
					devname);
				return -1;
			}
			if (chown(devname, ci->uid, ci->gid))
				perror("chown");
			if (chmod(devname, ci->mode))
				perror("chmod");
			stat(devname, &stb);
			add_dev(devname, &stb, 0, NULL);
		}
		if (use_mdp == 1)
			make_parts(devname, parts);

		if (strcmp(chosen, devname) != 0) {
			if (mkdir(DEV_NUM_PREF, 0700) == 0) {
				if (chown(DEV_NUM_PREF, ci->uid, ci->gid))
					perror("chown " DEV_NUM_PREF);
				if (chmod(DEV_NUM_PREF, ci->mode | ((ci->mode >> 2) & 0111)))
					perror("chmod " DEV_NUM_PREF);
			}

			if (dev && strcmp(chosen, dev) == 0)
				/* We know we are allowed to use this name */
				unlink(chosen);

			if (lstat(chosen, &stb) == 0) {
				char buf[300];
				ssize_t link_len = readlink(chosen, buf, sizeof(buf)-1);
				if (link_len >= 0)
					buf[link_len] = '\0';

				if ((stb.st_mode & S_IFMT) != S_IFLNK ||
				    link_len < 0 ||
				    strcmp(buf, devname) != 0) {
					pr_err("%s exists - ignoring\n",
						chosen);
					strcpy(chosen, devname);
				}
			} else if (symlink(devname, chosen) != 0)
				pr_err("failed to create %s: %s\n",
					chosen, strerror(errno));
			if (use_mdp && strcmp(chosen, devname) != 0)
				make_parts(chosen, parts);
		}
	}
	mdfd = open_dev_excl(devnm);
	if (mdfd < 0)
		pr_err("unexpected failure opening %s\n",
			devname);
	return mdfd;
}

/* Open this and check that it is an md device.
 * On success, return filedescriptor.
 * On failure, return -1 if it doesn't exist,
 * or -2 if it exists but is not an md device.
 */
int open_mddev(char *dev, int report_errors)
{
	int mdfd = open(dev, O_RDONLY);

	if (mdfd < 0) {
		if (report_errors)
			pr_err("error opening %s: %s\n",
				dev, strerror(errno));
		return -1;
	}

	if (md_array_valid(mdfd) == 0) {
		close(mdfd);
		if (report_errors)
			pr_err("%s does not appear to be an md device\n", dev);
		return -2;
	}

	return mdfd;
}

/**
 * is_mddev() - check that file name passed is an md device.
 * @dev: file name that has to be checked.
 * Return: 1 if file passed is an md device, 0 if not.
 */
int is_mddev(char *dev)
{
	int fd = open_mddev(dev, 1);

	if (fd >= 0) {
		close(fd);
		return 1;
	}

	return 0;
}

char *find_free_devnm(int use_partitions)
{
	static char devnm[32];
	int devnum;
	for (devnum = 127; devnum != 128;
	     devnum = devnum ? devnum-1 : (1<<9)-1) {

		if (use_partitions)
			sprintf(devnm, "md_d%d", devnum);
		else
			sprintf(devnm, "md%d", devnum);
		if (mddev_busy(devnm))
			continue;
		if (!conf_name_is_free(devnm))
			continue;
		if (!use_udev()) {
			/* make sure it is new to /dev too, at least as a
			 * non-standard */
			dev_t devid = devnm2devid(devnm);
			if (devid) {
				char *dn = map_dev(major(devid),
						   minor(devid), 0);
				if (dn && ! is_standard(dn, NULL))
					continue;
			}
		}
		break;
	}
	if (devnum == 128)
		return NULL;
	return devnm;
}