1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Copyright (C) 2013 HUAWEI |
4 | * Author: Cai Zhiyong <caizhiyong@huawei.com> |
5 | * |
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 |
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 | * |
14 | * For further information, see "Documentation/block/cmdline-partition.rst" |
15 | * |
16 | */ |
17 | #include <linux/blkdev.h> |
18 | #include <linux/fs.h> |
19 | #include <linux/slab.h> |
20 | #include "check.h" |
21 | |
22 | |
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(size: 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(ptr: partdef, retptr: &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(ptr: partdef, retptr: &partdef); |
68 | } else { |
69 | new_subpart->from = (sector_t)(~0ULL); |
70 | } |
71 | |
72 | if (*partdef == '(') { |
73 | int length; |
74 | char *next = strchr(++partdef, ')'); |
75 | |
76 | if (!next) { |
77 | pr_warn("cmdline partition format is invalid." ); |
78 | ret = -EINVAL; |
79 | goto fail; |
80 | } |
81 | |
82 | length = min_t(int, next - partdef, |
83 | sizeof(new_subpart->name) - 1); |
84 | strscpy(new_subpart->name, partdef, length); |
85 | |
86 | partdef = ++next; |
87 | } else |
88 | new_subpart->name[0] = '\0'; |
89 | |
90 | new_subpart->flags = 0; |
91 | |
92 | if (!strncmp(partdef, "ro" , 2)) { |
93 | new_subpart->flags |= PF_RDONLY; |
94 | partdef += 2; |
95 | } |
96 | |
97 | if (!strncmp(partdef, "lk" , 2)) { |
98 | new_subpart->flags |= PF_POWERUP_LOCK; |
99 | partdef += 2; |
100 | } |
101 | |
102 | *subpart = new_subpart; |
103 | return 0; |
104 | fail: |
105 | kfree(objp: new_subpart); |
106 | return ret; |
107 | } |
108 | |
109 | static void free_subpart(struct cmdline_parts *parts) |
110 | { |
111 | struct cmdline_subpart *subpart; |
112 | |
113 | while (parts->subpart) { |
114 | subpart = parts->subpart; |
115 | parts->subpart = subpart->next_subpart; |
116 | kfree(objp: subpart); |
117 | } |
118 | } |
119 | |
120 | static int parse_parts(struct cmdline_parts **parts, const char *bdevdef) |
121 | { |
122 | int ret = -EINVAL; |
123 | char *next; |
124 | int length; |
125 | struct cmdline_subpart **next_subpart; |
126 | struct cmdline_parts *newparts; |
127 | char buf[BDEVNAME_SIZE + 32 + 4]; |
128 | |
129 | *parts = NULL; |
130 | |
131 | newparts = kzalloc(size: sizeof(struct cmdline_parts), GFP_KERNEL); |
132 | if (!newparts) |
133 | return -ENOMEM; |
134 | |
135 | next = strchr(bdevdef, ':'); |
136 | if (!next) { |
137 | pr_warn("cmdline partition has no block device." ); |
138 | goto fail; |
139 | } |
140 | |
141 | length = min_t(int, next - bdevdef, sizeof(newparts->name) - 1); |
142 | strscpy(newparts->name, bdevdef, length); |
143 | newparts->nr_subparts = 0; |
144 | |
145 | next_subpart = &newparts->subpart; |
146 | |
147 | while (next && *(++next)) { |
148 | bdevdef = next; |
149 | next = strchr(bdevdef, ','); |
150 | |
151 | length = (!next) ? (sizeof(buf) - 1) : |
152 | min_t(int, next - bdevdef, sizeof(buf) - 1); |
153 | |
154 | strscpy(buf, bdevdef, length); |
155 | |
156 | ret = parse_subpart(subpart: next_subpart, partdef: buf); |
157 | if (ret) |
158 | goto fail; |
159 | |
160 | newparts->nr_subparts++; |
161 | next_subpart = &(*next_subpart)->next_subpart; |
162 | } |
163 | |
164 | if (!newparts->subpart) { |
165 | pr_warn("cmdline partition has no valid partition." ); |
166 | ret = -EINVAL; |
167 | goto fail; |
168 | } |
169 | |
170 | *parts = newparts; |
171 | |
172 | return 0; |
173 | fail: |
174 | free_subpart(parts: newparts); |
175 | kfree(objp: newparts); |
176 | return ret; |
177 | } |
178 | |
179 | static void cmdline_parts_free(struct cmdline_parts **parts) |
180 | { |
181 | struct cmdline_parts *next_parts; |
182 | |
183 | while (*parts) { |
184 | next_parts = (*parts)->next_parts; |
185 | free_subpart(parts: *parts); |
186 | kfree(objp: *parts); |
187 | *parts = next_parts; |
188 | } |
189 | } |
190 | |
191 | static int cmdline_parts_parse(struct cmdline_parts **parts, |
192 | const char *cmdline) |
193 | { |
194 | int ret; |
195 | char *buf; |
196 | char *pbuf; |
197 | char *next; |
198 | struct cmdline_parts **next_parts; |
199 | |
200 | *parts = NULL; |
201 | |
202 | next = pbuf = buf = kstrdup(s: cmdline, GFP_KERNEL); |
203 | if (!buf) |
204 | return -ENOMEM; |
205 | |
206 | next_parts = parts; |
207 | |
208 | while (next && *pbuf) { |
209 | next = strchr(pbuf, ';'); |
210 | if (next) |
211 | *next = '\0'; |
212 | |
213 | ret = parse_parts(parts: next_parts, bdevdef: pbuf); |
214 | if (ret) |
215 | goto fail; |
216 | |
217 | if (next) |
218 | pbuf = ++next; |
219 | |
220 | next_parts = &(*next_parts)->next_parts; |
221 | } |
222 | |
223 | if (!*parts) { |
224 | pr_warn("cmdline partition has no valid partition." ); |
225 | ret = -EINVAL; |
226 | goto fail; |
227 | } |
228 | |
229 | ret = 0; |
230 | done: |
231 | kfree(objp: buf); |
232 | return ret; |
233 | |
234 | fail: |
235 | cmdline_parts_free(parts); |
236 | goto done; |
237 | } |
238 | |
239 | static struct cmdline_parts *cmdline_parts_find(struct cmdline_parts *parts, |
240 | const char *bdev) |
241 | { |
242 | while (parts && strncmp(bdev, parts->name, sizeof(parts->name))) |
243 | parts = parts->next_parts; |
244 | return parts; |
245 | } |
246 | |
247 | static char *cmdline; |
248 | static struct cmdline_parts *bdev_parts; |
249 | |
250 | static int add_part(int slot, struct cmdline_subpart *subpart, |
251 | struct parsed_partitions *state) |
252 | { |
253 | int label_min; |
254 | struct partition_meta_info *info; |
255 | char tmp[sizeof(info->volname) + 4]; |
256 | |
257 | if (slot >= state->limit) |
258 | return 1; |
259 | |
260 | put_partition(p: state, n: slot, from: subpart->from >> 9, |
261 | size: subpart->size >> 9); |
262 | |
263 | info = &state->parts[slot].info; |
264 | |
265 | label_min = min_t(int, sizeof(info->volname) - 1, |
266 | sizeof(subpart->name)); |
267 | strscpy(info->volname, subpart->name, label_min); |
268 | |
269 | snprintf(buf: tmp, size: sizeof(tmp), fmt: "(%s)" , info->volname); |
270 | strlcat(p: state->pp_buf, q: tmp, PAGE_SIZE); |
271 | |
272 | state->parts[slot].has_info = true; |
273 | |
274 | return 0; |
275 | } |
276 | |
277 | static int cmdline_parts_set(struct cmdline_parts *parts, sector_t disk_size, |
278 | struct parsed_partitions *state) |
279 | { |
280 | sector_t from = 0; |
281 | struct cmdline_subpart *subpart; |
282 | int slot = 1; |
283 | |
284 | for (subpart = parts->subpart; subpart; |
285 | subpart = subpart->next_subpart, slot++) { |
286 | if (subpart->from == (sector_t)(~0ULL)) |
287 | subpart->from = from; |
288 | else |
289 | from = subpart->from; |
290 | |
291 | if (from >= disk_size) |
292 | break; |
293 | |
294 | if (subpart->size > (disk_size - from)) |
295 | subpart->size = disk_size - from; |
296 | |
297 | from += subpart->size; |
298 | |
299 | if (add_part(slot, subpart, state)) |
300 | break; |
301 | } |
302 | |
303 | return slot; |
304 | } |
305 | |
306 | static int __init cmdline_parts_setup(char *s) |
307 | { |
308 | cmdline = s; |
309 | return 1; |
310 | } |
311 | __setup("blkdevparts=" , cmdline_parts_setup); |
312 | |
313 | static bool has_overlaps(sector_t from, sector_t size, |
314 | sector_t from2, sector_t size2) |
315 | { |
316 | sector_t end = from + size; |
317 | sector_t end2 = from2 + size2; |
318 | |
319 | if (from >= from2 && from < end2) |
320 | return true; |
321 | |
322 | if (end > from2 && end <= end2) |
323 | return true; |
324 | |
325 | if (from2 >= from && from2 < end) |
326 | return true; |
327 | |
328 | if (end2 > from && end2 <= end) |
329 | return true; |
330 | |
331 | return false; |
332 | } |
333 | |
334 | static inline void (void) |
335 | { |
336 | pr_warn("Overlapping partitions are used in command line partitions." ); |
337 | pr_warn("Don't use filesystems on overlapping partitions:" ); |
338 | } |
339 | |
340 | static void cmdline_parts_verifier(int slot, struct parsed_partitions *state) |
341 | { |
342 | int i; |
343 | bool = true; |
344 | |
345 | for (; slot < state->limit && state->parts[slot].has_info; slot++) { |
346 | for (i = slot+1; i < state->limit && state->parts[i].has_info; |
347 | i++) { |
348 | if (has_overlaps(from: state->parts[slot].from, |
349 | size: state->parts[slot].size, |
350 | from2: state->parts[i].from, |
351 | size2: state->parts[i].size)) { |
352 | if (header) { |
353 | header = false; |
354 | overlaps_warns_header(); |
355 | } |
356 | pr_warn("%s[%llu,%llu] overlaps with " |
357 | "%s[%llu,%llu]." , |
358 | state->parts[slot].info.volname, |
359 | (u64)state->parts[slot].from << 9, |
360 | (u64)state->parts[slot].size << 9, |
361 | state->parts[i].info.volname, |
362 | (u64)state->parts[i].from << 9, |
363 | (u64)state->parts[i].size << 9); |
364 | } |
365 | } |
366 | } |
367 | } |
368 | |
369 | /* |
370 | * Purpose: allocate cmdline partitions. |
371 | * Returns: |
372 | * -1 if unable to read the partition table |
373 | * 0 if this isn't our partition table |
374 | * 1 if successful |
375 | */ |
376 | int cmdline_partition(struct parsed_partitions *state) |
377 | { |
378 | sector_t disk_size; |
379 | struct cmdline_parts *parts; |
380 | |
381 | if (cmdline) { |
382 | if (bdev_parts) |
383 | cmdline_parts_free(parts: &bdev_parts); |
384 | |
385 | if (cmdline_parts_parse(parts: &bdev_parts, cmdline)) { |
386 | cmdline = NULL; |
387 | return -1; |
388 | } |
389 | cmdline = NULL; |
390 | } |
391 | |
392 | if (!bdev_parts) |
393 | return 0; |
394 | |
395 | parts = cmdline_parts_find(parts: bdev_parts, bdev: state->disk->disk_name); |
396 | if (!parts) |
397 | return 0; |
398 | |
399 | disk_size = get_capacity(disk: state->disk) << 9; |
400 | |
401 | cmdline_parts_set(parts, disk_size, state); |
402 | cmdline_parts_verifier(slot: 1, state); |
403 | |
404 | strlcat(p: state->pp_buf, q: "\n" , PAGE_SIZE); |
405 | |
406 | return 1; |
407 | } |
408 | |