1 /* do_mounts_dm.c
2 * Copyright (C) 2010 The Chromium OS Authors <chromium-os-dev@chromium.org>
3 * All Rights Reserved.
4 * Based on do_mounts_md.c
5 *
6 * This file is released under the GPL.
7 */
8 #include <linux/async.h>
9 #include <linux/ctype.h>
10 #include <linux/device-mapper.h>
11 #include <linux/fs.h>
12 #include <linux/string.h>
13 #include <linux/delay.h>
14
15 #include "do_mounts.h"
16
17 #define DM_MAX_DEVICES 256
18 #define DM_MAX_TARGETS 256
19 #define DM_MAX_NAME 32
20 #define DM_MAX_UUID 129
21 #define DM_NO_UUID "none"
22
23 #define DM_MSG_PREFIX "init"
24
25 /* Separators used for parsing the dm= argument. */
26 #define DM_FIELD_SEP " "
27 #define DM_LINE_SEP ","
28 #define DM_ANY_SEP DM_FIELD_SEP DM_LINE_SEP
29
30 /*
31 * When the device-mapper and any targets are compiled into the kernel
32 * (not a module), one or more device-mappers may be created and used
33 * as the root device at boot time with the parameters given with the
34 * boot line dm=...
35 *
36 * Multiple device-mappers can be stacked specifing the number of
37 * devices. A device can have multiple targets if the the number of
38 * targets is specified.
39 *
40 * TODO(taysom:defect 32847)
41 * In the future, the <num> field will be mandatory.
42 *
43 * <device> ::= [<num>] <device-mapper>+
44 * <device-mapper> ::= <head> "," <target>+
45 * <head> ::= <name> <uuid> <mode> [<num>]
46 * <target> ::= <start> <length> <type> <options> ","
47 * <mode> ::= "ro" | "rw"
48 * <uuid> ::= xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx | "none"
49 * <type> ::= "verity" | "bootcache" | ...
50 *
51 * Example:
52 * 2 vboot none ro 1,
53 * 0 1768000 bootcache
54 * device=aa55b119-2a47-8c45-946a-5ac57765011f+1
55 * signature=76e9be054b15884a9fa85973e9cb274c93afadb6
56 * cache_start=1768000 max_blocks=100000 size_limit=23 max_trace=20000,
57 * vroot none ro 1,
58 * 0 1740800 verity payload=254:0 hashtree=254:0 hashstart=1740800 alg=sha1
59 * root_hexdigest=76e9be054b15884a9fa85973e9cb274c93afadb6
60 * salt=5b3549d54d6c7a3837b9b81ed72e49463a64c03680c47835bef94d768e5646fe
61 *
62 * Notes:
63 * 1. uuid is a label for the device and we set it to "none".
64 * 2. The <num> field will be optional initially and assumed to be 1.
65 * Once all the scripts that set these fields have been set, it will
66 * be made mandatory.
67 */
68
69 struct dm_setup_target {
70 sector_t begin;
71 sector_t length;
72 char *type;
73 char *params;
74 /* simple singly linked list */
75 struct dm_setup_target *next;
76 };
77
78 struct dm_device {
79 int minor;
80 int ro;
81 char name[DM_MAX_NAME];
82 char uuid[DM_MAX_UUID];
83 unsigned long num_targets;
84 struct dm_setup_target *target;
85 int target_count;
86 struct dm_device *next;
87 };
88
89 struct dm_option {
90 char *start;
91 char *next;
92 size_t len;
93 char delim;
94 };
95
96 static struct {
97 unsigned long num_devices;
98 char *str;
99 } dm_setup_args __initdata;
100
101 static __initdata int dm_early_setup;
102
get_dm_option(struct dm_option * opt,const char * accept)103 static int __init get_dm_option(struct dm_option *opt, const char *accept)
104 {
105 char *str = opt->next;
106 char *endp;
107
108 if (!str)
109 return 0;
110
111 str = skip_spaces(str);
112 opt->start = str;
113 endp = strpbrk(str, accept);
114 if (!endp) { /* act like strchrnul */
115 opt->len = strlen(str);
116 endp = str + opt->len;
117 } else {
118 opt->len = endp - str;
119 }
120 opt->delim = *endp;
121 if (*endp == 0) {
122 /* Don't advance past the nul. */
123 opt->next = endp;
124 } else {
125 opt->next = endp + 1;
126 }
127 return opt->len != 0;
128 }
129
dm_setup_cleanup(struct dm_device * devices)130 static int __init dm_setup_cleanup(struct dm_device *devices)
131 {
132 struct dm_device *dev = devices;
133
134 while (dev) {
135 struct dm_device *old_dev = dev;
136 struct dm_setup_target *target = dev->target;
137 while (target) {
138 struct dm_setup_target *old_target = target;
139 kfree(target->type);
140 kfree(target->params);
141 target = target->next;
142 kfree(old_target);
143 dev->target_count--;
144 }
145 BUG_ON(dev->target_count);
146 dev = dev->next;
147 kfree(old_dev);
148 }
149 return 0;
150 }
151
dm_parse_device(struct dm_device * dev,char * str)152 static char * __init dm_parse_device(struct dm_device *dev, char *str)
153 {
154 struct dm_option opt;
155 size_t len;
156
157 /* Grab the logical name of the device to be exported to udev */
158 opt.next = str;
159 if (!get_dm_option(&opt, DM_FIELD_SEP)) {
160 DMERR("failed to parse device name");
161 goto parse_fail;
162 }
163 len = min(opt.len + 1, sizeof(dev->name));
164 strlcpy(dev->name, opt.start, len); /* includes nul */
165
166 /* Grab the UUID value or "none" */
167 if (!get_dm_option(&opt, DM_FIELD_SEP)) {
168 DMERR("failed to parse device uuid");
169 goto parse_fail;
170 }
171 len = min(opt.len + 1, sizeof(dev->uuid));
172 strlcpy(dev->uuid, opt.start, len);
173
174 /* Determine if the table/device will be read only or read-write */
175 get_dm_option(&opt, DM_ANY_SEP);
176 if (!strncmp("ro", opt.start, opt.len)) {
177 dev->ro = 1;
178 } else if (!strncmp("rw", opt.start, opt.len)) {
179 dev->ro = 0;
180 } else {
181 DMERR("failed to parse table mode");
182 goto parse_fail;
183 }
184
185 /* Optional number field */
186 /* XXX: The <num> field will be mandatory in the next round */
187 if (opt.delim == DM_FIELD_SEP[0]) {
188 if (!get_dm_option(&opt, DM_LINE_SEP))
189 return NULL;
190 dev->num_targets = simple_strtoul(opt.start, NULL, 10);
191 } else {
192 dev->num_targets = 1;
193 }
194 if (dev->num_targets > DM_MAX_TARGETS) {
195 DMERR("too many targets %lu > %d",
196 dev->num_targets, DM_MAX_TARGETS);
197 }
198 return opt.next;
199
200 parse_fail:
201 return NULL;
202 }
203
dm_parse_targets(struct dm_device * dev,char * str)204 static char * __init dm_parse_targets(struct dm_device *dev, char *str)
205 {
206 struct dm_option opt;
207 struct dm_setup_target **target = &dev->target;
208 unsigned long num_targets = dev->num_targets;
209 unsigned long i;
210
211 /* Targets are defined as per the table format but with a
212 * comma as a newline separator. */
213 opt.next = str;
214 for (i = 0; i < num_targets; i++) {
215 *target = kzalloc(sizeof(struct dm_setup_target), GFP_KERNEL);
216 if (!*target) {
217 DMERR("failed to allocate memory for target %s<%ld>",
218 dev->name, i);
219 goto parse_fail;
220 }
221 dev->target_count++;
222
223 if (!get_dm_option(&opt, DM_FIELD_SEP)) {
224 DMERR("failed to parse starting sector"
225 " for target %s<%ld>", dev->name, i);
226 goto parse_fail;
227 }
228 (*target)->begin = simple_strtoull(opt.start, NULL, 10);
229
230 if (!get_dm_option(&opt, DM_FIELD_SEP)) {
231 DMERR("failed to parse length for target %s<%ld>",
232 dev->name, i);
233 goto parse_fail;
234 }
235 (*target)->length = simple_strtoull(opt.start, NULL, 10);
236
237 if (get_dm_option(&opt, DM_FIELD_SEP))
238 (*target)->type = kstrndup(opt.start, opt.len,
239 GFP_KERNEL);
240 if (!((*target)->type)) {
241 DMERR("failed to parse type for target %s<%ld>",
242 dev->name, i);
243 goto parse_fail;
244 }
245 if (get_dm_option(&opt, DM_LINE_SEP))
246 (*target)->params = kstrndup(opt.start, opt.len,
247 GFP_KERNEL);
248 if (!((*target)->params)) {
249 DMERR("failed to parse params for target %s<%ld>",
250 dev->name, i);
251 goto parse_fail;
252 }
253 target = &((*target)->next);
254 }
255 DMDEBUG("parsed %d targets", dev->target_count);
256
257 return opt.next;
258
259 parse_fail:
260 return NULL;
261 }
262
dm_parse_args(void)263 static struct dm_device * __init dm_parse_args(void)
264 {
265 struct dm_device *devices = NULL;
266 struct dm_device **tail = &devices;
267 struct dm_device *dev;
268 char *str = dm_setup_args.str;
269 unsigned long num_devices = dm_setup_args.num_devices;
270 unsigned long i;
271
272 if (!str)
273 return NULL;
274 for (i = 0; i < num_devices; i++) {
275 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
276 if (!dev) {
277 DMERR("failed to allocated memory for dev");
278 goto error;
279 }
280 *tail = dev;
281 tail = &dev->next;
282 /*
283 * devices are given minor numbers 0 - n-1
284 * in the order they are found in the arg
285 * string.
286 */
287 dev->minor = i;
288 str = dm_parse_device(dev, str);
289 if (!str) /* NULL indicates error in parsing, bail */
290 goto error;
291
292 str = dm_parse_targets(dev, str);
293 if (!str)
294 goto error;
295 }
296 return devices;
297 error:
298 dm_setup_cleanup(devices);
299 return NULL;
300 }
301
302 /*
303 * Parse the command-line parameters given our kernel, but do not
304 * actually try to invoke the DM device now; that is handled by
305 * dm_setup_drives after the low-level disk drivers have initialised.
306 * dm format is described at the top of the file.
307 *
308 * Because dm minor numbers are assigned in assending order starting with 0,
309 * You can assume the first device is /dev/dm-0, the next device is /dev/dm-1,
310 * and so forth.
311 */
dm_setup(char * str)312 static int __init dm_setup(char *str)
313 {
314 struct dm_option opt;
315 unsigned long num_devices;
316
317 if (!str) {
318 DMDEBUG("str is NULL");
319 goto parse_fail;
320 }
321 opt.next = str;
322 if (!get_dm_option(&opt, DM_FIELD_SEP))
323 goto parse_fail;
324 if (isdigit(opt.start[0])) { /* XXX: Optional number field */
325 num_devices = simple_strtoul(opt.start, NULL, 10);
326 str = opt.next;
327 } else {
328 num_devices = 1;
329 /* Don't advance str */
330 }
331 if (num_devices > DM_MAX_DEVICES) {
332 DMDEBUG("too many devices %lu > %d",
333 num_devices, DM_MAX_DEVICES);
334 }
335 dm_setup_args.str = str;
336 dm_setup_args.num_devices = num_devices;
337 DMINFO("will configure %lu devices", num_devices);
338 dm_early_setup = 1;
339 return 1;
340
341 parse_fail:
342 DMWARN("Invalid arguments supplied to dm=.");
343 return 0;
344 }
345
dm_setup_drives(void)346 static void __init dm_setup_drives(void)
347 {
348 struct mapped_device *md = NULL;
349 struct dm_table *table = NULL;
350 struct dm_setup_target *target;
351 struct dm_device *dev;
352 char *uuid;
353 fmode_t fmode = FMODE_READ;
354 struct dm_device *devices;
355
356 devices = dm_parse_args();
357
358 for (dev = devices; dev; dev = dev->next) {
359 if (dm_create(dev->minor, &md)) {
360 DMDEBUG("failed to create the device");
361 goto dm_create_fail;
362 }
363 DMDEBUG("created device '%s'", dm_device_name(md));
364
365 /*
366 * In addition to flagging the table below, the disk must be
367 * set explicitly ro/rw.
368 */
369 set_disk_ro(dm_disk(md), dev->ro);
370
371 if (!dev->ro)
372 fmode |= FMODE_WRITE;
373 if (dm_table_create(&table, fmode, dev->target_count, md)) {
374 DMDEBUG("failed to create the table");
375 goto dm_table_create_fail;
376 }
377
378 dm_lock_md_type(md);
379
380 for (target = dev->target; target; target = target->next) {
381 DMINFO("adding target '%llu %llu %s %s'",
382 (unsigned long long) target->begin,
383 (unsigned long long) target->length,
384 target->type, target->params);
385 if (dm_table_add_target(table, target->type,
386 target->begin,
387 target->length,
388 target->params)) {
389 DMDEBUG("failed to add the target"
390 " to the table");
391 goto add_target_fail;
392 }
393 }
394 if (dm_table_complete(table)) {
395 DMDEBUG("failed to complete the table");
396 goto table_complete_fail;
397 }
398
399 /* Suspend the device so that we can bind it to the table. */
400 if (dm_suspend(md, 0)) {
401 DMDEBUG("failed to suspend the device pre-bind");
402 goto suspend_fail;
403 }
404
405 /* Initial table load: acquire type of table. */
406 dm_set_md_type(md, dm_table_get_type(table));
407
408 /* Setup md->queue to reflect md's type. */
409 if (dm_setup_md_queue(md)) {
410 DMWARN("unable to set up device queue for new table.");
411 goto setup_md_queue_fail;
412 }
413
414 /*
415 * Bind the table to the device. This is the only way
416 * to associate md->map with the table and set the disk
417 * capacity directly.
418 */
419 if (dm_swap_table(md, table)) { /* should return NULL. */
420 DMDEBUG("failed to bind the device to the table");
421 goto table_bind_fail;
422 }
423
424 /* Finally, resume and the device should be ready. */
425 if (dm_resume(md)) {
426 DMDEBUG("failed to resume the device");
427 goto resume_fail;
428 }
429
430 /* Export the dm device via the ioctl interface */
431 if (!strcmp(DM_NO_UUID, dev->uuid))
432 uuid = NULL;
433 if (dm_ioctl_export(md, dev->name, uuid)) {
434 DMDEBUG("failed to export device with given"
435 " name and uuid");
436 goto export_fail;
437 }
438
439 dm_unlock_md_type(md);
440
441 DMINFO("dm-%d is ready", dev->minor);
442 }
443 dm_setup_cleanup(devices);
444 return;
445
446 export_fail:
447 resume_fail:
448 table_bind_fail:
449 setup_md_queue_fail:
450 suspend_fail:
451 table_complete_fail:
452 add_target_fail:
453 dm_unlock_md_type(md);
454 dm_table_create_fail:
455 dm_put(md);
456 dm_create_fail:
457 DMWARN("starting dm-%d (%s) failed",
458 dev->minor, dev->name);
459 dm_setup_cleanup(devices);
460 }
461
462 __setup("dm=", dm_setup);
463
dm_run_setup(void)464 void __init dm_run_setup(void)
465 {
466 if (!dm_early_setup)
467 return;
468 DMINFO("attempting early device configuration.");
469 dm_setup_drives();
470 }
471