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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
bab55417 CZ |
2 | /* |
3 | * Copyright (C) 2013 HUAWEI | |
4 | * Author: Cai Zhiyong <caizhiyong@huawei.com> | |
5 | * | |
080506ad PG |
6 | * Read block device partition table from the command line. |
7 | * Typically used for fixed block (eMMC) embedded devices. | |
8 | * It has no MBR, so saves storage space. Bootloader can be easily accessed | |
bab55417 CZ |
9 | * by absolute address of data on the block device. |
10 | * Users can easily change the partition. | |
11 | * | |
12 | * The format for the command line is just like mtdparts. | |
13 | * | |
898bd37a | 14 | * For further information, see "Documentation/block/cmdline-partition.rst" |
bab55417 CZ |
15 | * |
16 | */ | |
2164877c CH |
17 | #include <linux/blkdev.h> |
18 | #include <linux/fs.h> | |
19 | #include <linux/slab.h> | |
20 | #include "check.h" | |
bab55417 | 21 | |
bab55417 | 22 | |
2164877c CH |
23 | /* partition flags */ |
24 | #define PF_RDONLY 0x01 /* Device is read only */ | |
25 | #define PF_POWERUP_LOCK 0x02 /* Always locked after reset */ | |
26 | ||
27 | struct cmdline_subpart { | |
28 | char name[BDEVNAME_SIZE]; /* partition name, such as 'rootfs' */ | |
29 | sector_t from; | |
30 | sector_t size; | |
31 | int flags; | |
32 | struct cmdline_subpart *next_subpart; | |
33 | }; | |
34 | ||
35 | struct cmdline_parts { | |
36 | char name[BDEVNAME_SIZE]; /* block device, such as 'mmcblk0' */ | |
37 | unsigned int nr_subparts; | |
38 | struct cmdline_subpart *subpart; | |
39 | struct cmdline_parts *next_parts; | |
40 | }; | |
41 | ||
42 | static int parse_subpart(struct cmdline_subpart **subpart, char *partdef) | |
43 | { | |
44 | int ret = 0; | |
45 | struct cmdline_subpart *new_subpart; | |
46 | ||
47 | *subpart = NULL; | |
48 | ||
49 | new_subpart = kzalloc(sizeof(struct cmdline_subpart), GFP_KERNEL); | |
50 | if (!new_subpart) | |
51 | return -ENOMEM; | |
52 | ||
53 | if (*partdef == '-') { | |
54 | new_subpart->size = (sector_t)(~0ULL); | |
55 | partdef++; | |
56 | } else { | |
57 | new_subpart->size = (sector_t)memparse(partdef, &partdef); | |
58 | if (new_subpart->size < (sector_t)PAGE_SIZE) { | |
59 | pr_warn("cmdline partition size is invalid."); | |
60 | ret = -EINVAL; | |
61 | goto fail; | |
62 | } | |
63 | } | |
64 | ||
65 | if (*partdef == '@') { | |
66 | partdef++; | |
67 | new_subpart->from = (sector_t)memparse(partdef, &partdef); | |
68 | } else { | |
69 | new_subpart->from = (sector_t)(~0ULL); | |
70 | } | |
71 | ||
72 | if (*partdef == '(') { | |
bc2e07df IH |
73 | partdef++; |
74 | char *next = strsep(&partdef, ")"); | |
2164877c CH |
75 | |
76 | if (!next) { | |
77 | pr_warn("cmdline partition format is invalid."); | |
78 | ret = -EINVAL; | |
79 | goto fail; | |
80 | } | |
81 | ||
bc2e07df | 82 | strscpy(new_subpart->name, next, sizeof(new_subpart->name)); |
2164877c CH |
83 | } else |
84 | new_subpart->name[0] = '\0'; | |
85 | ||
86 | new_subpart->flags = 0; | |
87 | ||
88 | if (!strncmp(partdef, "ro", 2)) { | |
89 | new_subpart->flags |= PF_RDONLY; | |
90 | partdef += 2; | |
91 | } | |
92 | ||
93 | if (!strncmp(partdef, "lk", 2)) { | |
94 | new_subpart->flags |= PF_POWERUP_LOCK; | |
95 | partdef += 2; | |
96 | } | |
97 | ||
98 | *subpart = new_subpart; | |
99 | return 0; | |
100 | fail: | |
101 | kfree(new_subpart); | |
102 | return ret; | |
103 | } | |
104 | ||
105 | static void free_subpart(struct cmdline_parts *parts) | |
106 | { | |
107 | struct cmdline_subpart *subpart; | |
108 | ||
109 | while (parts->subpart) { | |
110 | subpart = parts->subpart; | |
111 | parts->subpart = subpart->next_subpart; | |
112 | kfree(subpart); | |
113 | } | |
114 | } | |
115 | ||
bc2e07df | 116 | static int parse_parts(struct cmdline_parts **parts, char *bdevdef) |
2164877c CH |
117 | { |
118 | int ret = -EINVAL; | |
119 | char *next; | |
2164877c CH |
120 | struct cmdline_subpart **next_subpart; |
121 | struct cmdline_parts *newparts; | |
2164877c CH |
122 | |
123 | *parts = NULL; | |
124 | ||
125 | newparts = kzalloc(sizeof(struct cmdline_parts), GFP_KERNEL); | |
126 | if (!newparts) | |
127 | return -ENOMEM; | |
128 | ||
bc2e07df | 129 | next = strsep(&bdevdef, ":"); |
2164877c CH |
130 | if (!next) { |
131 | pr_warn("cmdline partition has no block device."); | |
132 | goto fail; | |
133 | } | |
134 | ||
bc2e07df | 135 | strscpy(newparts->name, next, sizeof(newparts->name)); |
2164877c CH |
136 | newparts->nr_subparts = 0; |
137 | ||
138 | next_subpart = &newparts->subpart; | |
139 | ||
bc2e07df IH |
140 | while ((next = strsep(&bdevdef, ","))) { |
141 | ret = parse_subpart(next_subpart, next); | |
2164877c CH |
142 | if (ret) |
143 | goto fail; | |
144 | ||
145 | newparts->nr_subparts++; | |
146 | next_subpart = &(*next_subpart)->next_subpart; | |
147 | } | |
148 | ||
149 | if (!newparts->subpart) { | |
150 | pr_warn("cmdline partition has no valid partition."); | |
151 | ret = -EINVAL; | |
152 | goto fail; | |
153 | } | |
154 | ||
155 | *parts = newparts; | |
156 | ||
157 | return 0; | |
158 | fail: | |
159 | free_subpart(newparts); | |
160 | kfree(newparts); | |
161 | return ret; | |
162 | } | |
163 | ||
164 | static void cmdline_parts_free(struct cmdline_parts **parts) | |
165 | { | |
166 | struct cmdline_parts *next_parts; | |
167 | ||
168 | while (*parts) { | |
169 | next_parts = (*parts)->next_parts; | |
170 | free_subpart(*parts); | |
171 | kfree(*parts); | |
172 | *parts = next_parts; | |
173 | } | |
174 | } | |
175 | ||
176 | static int cmdline_parts_parse(struct cmdline_parts **parts, | |
177 | const char *cmdline) | |
178 | { | |
179 | int ret; | |
180 | char *buf; | |
181 | char *pbuf; | |
182 | char *next; | |
183 | struct cmdline_parts **next_parts; | |
184 | ||
185 | *parts = NULL; | |
186 | ||
bc2e07df | 187 | pbuf = buf = kstrdup(cmdline, GFP_KERNEL); |
2164877c CH |
188 | if (!buf) |
189 | return -ENOMEM; | |
190 | ||
191 | next_parts = parts; | |
192 | ||
bc2e07df IH |
193 | while ((next = strsep(&pbuf, ";"))) { |
194 | ret = parse_parts(next_parts, next); | |
2164877c CH |
195 | if (ret) |
196 | goto fail; | |
197 | ||
2164877c CH |
198 | next_parts = &(*next_parts)->next_parts; |
199 | } | |
200 | ||
201 | if (!*parts) { | |
202 | pr_warn("cmdline partition has no valid partition."); | |
203 | ret = -EINVAL; | |
204 | goto fail; | |
205 | } | |
206 | ||
207 | ret = 0; | |
208 | done: | |
209 | kfree(buf); | |
210 | return ret; | |
211 | ||
212 | fail: | |
213 | cmdline_parts_free(parts); | |
214 | goto done; | |
215 | } | |
216 | ||
217 | static struct cmdline_parts *cmdline_parts_find(struct cmdline_parts *parts, | |
218 | const char *bdev) | |
219 | { | |
220 | while (parts && strncmp(bdev, parts->name, sizeof(parts->name))) | |
221 | parts = parts->next_parts; | |
222 | return parts; | |
223 | } | |
bab55417 CZ |
224 | |
225 | static char *cmdline; | |
226 | static struct cmdline_parts *bdev_parts; | |
227 | ||
2164877c CH |
228 | static int add_part(int slot, struct cmdline_subpart *subpart, |
229 | struct parsed_partitions *state) | |
bab55417 | 230 | { |
bab55417 CZ |
231 | struct partition_meta_info *info; |
232 | char tmp[sizeof(info->volname) + 4]; | |
bab55417 CZ |
233 | |
234 | if (slot >= state->limit) | |
235 | return 1; | |
236 | ||
237 | put_partition(state, slot, subpart->from >> 9, | |
238 | subpart->size >> 9); | |
239 | ||
240 | info = &state->parts[slot].info; | |
241 | ||
bc2e07df | 242 | strscpy(info->volname, subpart->name, sizeof(info->volname)); |
bab55417 CZ |
243 | |
244 | snprintf(tmp, sizeof(tmp), "(%s)", info->volname); | |
245 | strlcat(state->pp_buf, tmp, PAGE_SIZE); | |
246 | ||
247 | state->parts[slot].has_info = true; | |
248 | ||
249 | return 0; | |
250 | } | |
251 | ||
2164877c CH |
252 | static int cmdline_parts_set(struct cmdline_parts *parts, sector_t disk_size, |
253 | struct parsed_partitions *state) | |
254 | { | |
255 | sector_t from = 0; | |
256 | struct cmdline_subpart *subpart; | |
257 | int slot = 1; | |
258 | ||
259 | for (subpart = parts->subpart; subpart; | |
260 | subpart = subpart->next_subpart, slot++) { | |
261 | if (subpart->from == (sector_t)(~0ULL)) | |
262 | subpart->from = from; | |
263 | else | |
264 | from = subpart->from; | |
265 | ||
266 | if (from >= disk_size) | |
267 | break; | |
268 | ||
269 | if (subpart->size > (disk_size - from)) | |
270 | subpart->size = disk_size - from; | |
271 | ||
272 | from += subpart->size; | |
273 | ||
274 | if (add_part(slot, subpart, state)) | |
275 | break; | |
276 | } | |
277 | ||
278 | return slot; | |
279 | } | |
280 | ||
bab55417 CZ |
281 | static int __init cmdline_parts_setup(char *s) |
282 | { | |
283 | cmdline = s; | |
284 | return 1; | |
285 | } | |
286 | __setup("blkdevparts=", cmdline_parts_setup); | |
287 | ||
645d4095 WY |
288 | static bool has_overlaps(sector_t from, sector_t size, |
289 | sector_t from2, sector_t size2) | |
290 | { | |
291 | sector_t end = from + size; | |
292 | sector_t end2 = from2 + size2; | |
293 | ||
294 | if (from >= from2 && from < end2) | |
295 | return true; | |
296 | ||
297 | if (end > from2 && end <= end2) | |
298 | return true; | |
299 | ||
300 | if (from2 >= from && from2 < end) | |
301 | return true; | |
302 | ||
303 | if (end2 > from && end2 <= end) | |
304 | return true; | |
305 | ||
306 | return false; | |
307 | } | |
308 | ||
309 | static inline void overlaps_warns_header(void) | |
310 | { | |
311 | pr_warn("Overlapping partitions are used in command line partitions."); | |
312 | pr_warn("Don't use filesystems on overlapping partitions:"); | |
313 | } | |
314 | ||
315 | static void cmdline_parts_verifier(int slot, struct parsed_partitions *state) | |
316 | { | |
317 | int i; | |
318 | bool header = true; | |
319 | ||
320 | for (; slot < state->limit && state->parts[slot].has_info; slot++) { | |
321 | for (i = slot+1; i < state->limit && state->parts[i].has_info; | |
322 | i++) { | |
323 | if (has_overlaps(state->parts[slot].from, | |
324 | state->parts[slot].size, | |
325 | state->parts[i].from, | |
326 | state->parts[i].size)) { | |
327 | if (header) { | |
328 | header = false; | |
329 | overlaps_warns_header(); | |
330 | } | |
331 | pr_warn("%s[%llu,%llu] overlaps with " | |
332 | "%s[%llu,%llu].", | |
333 | state->parts[slot].info.volname, | |
334 | (u64)state->parts[slot].from << 9, | |
335 | (u64)state->parts[slot].size << 9, | |
336 | state->parts[i].info.volname, | |
337 | (u64)state->parts[i].from << 9, | |
338 | (u64)state->parts[i].size << 9); | |
339 | } | |
340 | } | |
341 | } | |
342 | } | |
343 | ||
bab55417 CZ |
344 | /* |
345 | * Purpose: allocate cmdline partitions. | |
346 | * Returns: | |
347 | * -1 if unable to read the partition table | |
348 | * 0 if this isn't our partition table | |
349 | * 1 if successful | |
350 | */ | |
351 | int cmdline_partition(struct parsed_partitions *state) | |
352 | { | |
353 | sector_t disk_size; | |
bab55417 CZ |
354 | struct cmdline_parts *parts; |
355 | ||
356 | if (cmdline) { | |
357 | if (bdev_parts) | |
358 | cmdline_parts_free(&bdev_parts); | |
359 | ||
360 | if (cmdline_parts_parse(&bdev_parts, cmdline)) { | |
361 | cmdline = NULL; | |
362 | return -1; | |
363 | } | |
364 | cmdline = NULL; | |
365 | } | |
366 | ||
367 | if (!bdev_parts) | |
368 | return 0; | |
369 | ||
a08aa9bc | 370 | parts = cmdline_parts_find(bdev_parts, state->disk->disk_name); |
bab55417 CZ |
371 | if (!parts) |
372 | return 0; | |
373 | ||
a08aa9bc | 374 | disk_size = get_capacity(state->disk) << 9; |
bab55417 | 375 | |
2164877c | 376 | cmdline_parts_set(parts, disk_size, state); |
645d4095 | 377 | cmdline_parts_verifier(1, state); |
bab55417 CZ |
378 | |
379 | strlcat(state->pp_buf, "\n", PAGE_SIZE); | |
380 | ||
381 | return 1; | |
382 | } |