blob: af84b01ccfbc7022266e3ac2b2aa8885a0182f9e
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 | |
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 | |
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 | |
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 | |
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 | |
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 | */ |
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 | |
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, table)) { |
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 | |
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 |