Contents of /trunk/mkinitrd-magellan/busybox/e2fsprogs/old_e2fsprogs/blkid/read.c
Parent Directory | Revision Log
Revision 984 -
(show annotations)
(download)
Sun May 30 11:32:42 2010 UTC (14 years ago) by niro
File MIME type: text/plain
File size: 9693 byte(s)
Sun May 30 11:32:42 2010 UTC (14 years ago) by niro
File MIME type: text/plain
File size: 9693 byte(s)
-updated to busybox-1.16.1 and enabled blkid/uuid support in default config
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * read.c - read the blkid cache from disk, to avoid scanning all devices |
4 | * |
5 | * Copyright (C) 2001, 2003 Theodore Y. Ts'o |
6 | * Copyright (C) 2001 Andreas Dilger |
7 | * |
8 | * %Begin-Header% |
9 | * This file may be redistributed under the terms of the |
10 | * GNU Lesser General Public License. |
11 | * %End-Header% |
12 | */ |
13 | |
14 | #include <stdio.h> |
15 | #include <ctype.h> |
16 | #include <string.h> |
17 | #include <time.h> |
18 | #include <sys/types.h> |
19 | #include <sys/stat.h> |
20 | #include <fcntl.h> |
21 | #include <unistd.h> |
22 | #include <errno.h> |
23 | |
24 | #include "blkidP.h" |
25 | #include "../uuid/uuid.h" |
26 | |
27 | #ifdef HAVE_STRTOULL |
28 | #define __USE_ISOC9X |
29 | #define STRTOULL strtoull /* defined in stdlib.h if you try hard enough */ |
30 | #else |
31 | /* FIXME: need to support real strtoull here */ |
32 | #define STRTOULL strtoul |
33 | #endif |
34 | |
35 | #include <stdlib.h> |
36 | |
37 | #ifdef TEST_PROGRAM |
38 | #define blkid_debug_dump_dev(dev) (debug_dump_dev(dev)) |
39 | static void debug_dump_dev(blkid_dev dev); |
40 | #endif |
41 | |
42 | /* |
43 | * File format: |
44 | * |
45 | * <device [<NAME="value"> ...]>device_name</device> |
46 | * |
47 | * The following tags are required for each entry: |
48 | * <ID="id"> unique (within this file) ID number of this device |
49 | * <TIME="time"> (ascii time_t) time this entry was last read from disk |
50 | * <TYPE="type"> (detected) type of filesystem/data for this partition |
51 | * |
52 | * The following tags may be present, depending on the device contents |
53 | * <LABEL="label"> (user supplied) label (volume name, etc) |
54 | * <UUID="uuid"> (generated) universally unique identifier (serial no) |
55 | */ |
56 | |
57 | static char *skip_over_blank(char *cp) |
58 | { |
59 | while (*cp && isspace(*cp)) |
60 | cp++; |
61 | return cp; |
62 | } |
63 | |
64 | static char *skip_over_word(char *cp) |
65 | { |
66 | char ch; |
67 | |
68 | while ((ch = *cp)) { |
69 | /* If we see a backslash, skip the next character */ |
70 | if (ch == '\\') { |
71 | cp++; |
72 | if (*cp == '\0') |
73 | break; |
74 | cp++; |
75 | continue; |
76 | } |
77 | if (isspace(ch) || ch == '<' || ch == '>') |
78 | break; |
79 | cp++; |
80 | } |
81 | return cp; |
82 | } |
83 | |
84 | static char *strip_line(char *line) |
85 | { |
86 | char *p; |
87 | |
88 | line = skip_over_blank(line); |
89 | |
90 | p = line + strlen(line) - 1; |
91 | |
92 | while (*line) { |
93 | if (isspace(*p)) |
94 | *p-- = '\0'; |
95 | else |
96 | break; |
97 | } |
98 | |
99 | return line; |
100 | } |
101 | |
102 | /* |
103 | * Start parsing a new line from the cache. |
104 | * |
105 | * line starts with "<device" return 1 -> continue parsing line |
106 | * line starts with "<foo", empty, or # return 0 -> skip line |
107 | * line starts with other, return -BLKID_ERR_CACHE -> error |
108 | */ |
109 | static int parse_start(char **cp) |
110 | { |
111 | char *p; |
112 | |
113 | p = strip_line(*cp); |
114 | |
115 | /* Skip comment or blank lines. We can't just NUL the first '#' char, |
116 | * in case it is inside quotes, or escaped. |
117 | */ |
118 | if (*p == '\0' || *p == '#') |
119 | return 0; |
120 | |
121 | if (!strncmp(p, "<device", 7)) { |
122 | DBG(DEBUG_READ, printf("found device header: %8s\n", p)); |
123 | p += 7; |
124 | |
125 | *cp = p; |
126 | return 1; |
127 | } |
128 | |
129 | if (*p == '<') |
130 | return 0; |
131 | |
132 | return -BLKID_ERR_CACHE; |
133 | } |
134 | |
135 | /* Consume the remaining XML on the line (cosmetic only) */ |
136 | static int parse_end(char **cp) |
137 | { |
138 | *cp = skip_over_blank(*cp); |
139 | |
140 | if (!strncmp(*cp, "</device>", 9)) { |
141 | DBG(DEBUG_READ, printf("found device trailer %9s\n", *cp)); |
142 | *cp += 9; |
143 | return 0; |
144 | } |
145 | |
146 | return -BLKID_ERR_CACHE; |
147 | } |
148 | |
149 | /* |
150 | * Allocate a new device struct with device name filled in. Will handle |
151 | * finding the device on lines of the form: |
152 | * <device foo=bar>devname</device> |
153 | * <device>devname<foo>bar</foo></device> |
154 | */ |
155 | static int parse_dev(blkid_cache cache, blkid_dev *dev, char **cp) |
156 | { |
157 | char *start, *tmp, *end, *name; |
158 | int ret; |
159 | |
160 | if ((ret = parse_start(cp)) <= 0) |
161 | return ret; |
162 | |
163 | start = tmp = strchr(*cp, '>'); |
164 | if (!start) { |
165 | DBG(DEBUG_READ, |
166 | printf("blkid: short line parsing dev: %s\n", *cp)); |
167 | return -BLKID_ERR_CACHE; |
168 | } |
169 | start = skip_over_blank(start + 1); |
170 | end = skip_over_word(start); |
171 | |
172 | DBG(DEBUG_READ, printf("device should be %*s\n", end - start, start)); |
173 | |
174 | if (**cp == '>') |
175 | *cp = end; |
176 | else |
177 | (*cp)++; |
178 | |
179 | *tmp = '\0'; |
180 | |
181 | if (!(tmp = strrchr(end, '<')) || parse_end(&tmp) < 0) { |
182 | DBG(DEBUG_READ, |
183 | printf("blkid: missing </device> ending: %s\n", end)); |
184 | } else if (tmp) |
185 | *tmp = '\0'; |
186 | |
187 | if (end - start <= 1) { |
188 | DBG(DEBUG_READ, printf("blkid: empty device name: %s\n", *cp)); |
189 | return -BLKID_ERR_CACHE; |
190 | } |
191 | |
192 | name = blkid_strndup(start, end-start); |
193 | if (name == NULL) |
194 | return -BLKID_ERR_MEM; |
195 | |
196 | DBG(DEBUG_READ, printf("found dev %s\n", name)); |
197 | |
198 | if (!(*dev = blkid_get_dev(cache, name, BLKID_DEV_CREATE))) |
199 | return -BLKID_ERR_MEM; |
200 | |
201 | free(name); |
202 | return 1; |
203 | } |
204 | |
205 | /* |
206 | * Extract a tag of the form NAME="value" from the line. |
207 | */ |
208 | static int parse_token(char **name, char **value, char **cp) |
209 | { |
210 | char *end; |
211 | |
212 | if (!name || !value || !cp) |
213 | return -BLKID_ERR_PARAM; |
214 | |
215 | if (!(*value = strchr(*cp, '='))) |
216 | return 0; |
217 | |
218 | **value = '\0'; |
219 | *name = strip_line(*cp); |
220 | *value = skip_over_blank(*value + 1); |
221 | |
222 | if (**value == '"') { |
223 | end = strchr(*value + 1, '"'); |
224 | if (!end) { |
225 | DBG(DEBUG_READ, |
226 | printf("unbalanced quotes at: %s\n", *value)); |
227 | *cp = *value; |
228 | return -BLKID_ERR_CACHE; |
229 | } |
230 | (*value)++; |
231 | *end = '\0'; |
232 | end++; |
233 | } else { |
234 | end = skip_over_word(*value); |
235 | if (*end) { |
236 | *end = '\0'; |
237 | end++; |
238 | } |
239 | } |
240 | *cp = end; |
241 | |
242 | return 1; |
243 | } |
244 | |
245 | /* |
246 | * Extract a tag of the form <NAME>value</NAME> from the line. |
247 | */ |
248 | /* |
249 | static int parse_xml(char **name, char **value, char **cp) |
250 | { |
251 | char *end; |
252 | |
253 | if (!name || !value || !cp) |
254 | return -BLKID_ERR_PARAM; |
255 | |
256 | *name = strip_line(*cp); |
257 | |
258 | if ((*name)[0] != '<' || (*name)[1] == '/') |
259 | return 0; |
260 | |
261 | FIXME: finish this. |
262 | } |
263 | */ |
264 | |
265 | /* |
266 | * Extract a tag from the line. |
267 | * |
268 | * Return 1 if a valid tag was found. |
269 | * Return 0 if no tag found. |
270 | * Return -ve error code. |
271 | */ |
272 | static int parse_tag(blkid_cache cache, blkid_dev dev, char **cp) |
273 | { |
274 | char *name; |
275 | char *value; |
276 | int ret; |
277 | |
278 | if (!cache || !dev) |
279 | return -BLKID_ERR_PARAM; |
280 | |
281 | if ((ret = parse_token(&name, &value, cp)) <= 0 /* && |
282 | (ret = parse_xml(&name, &value, cp)) <= 0 */) |
283 | return ret; |
284 | |
285 | /* Some tags are stored directly in the device struct */ |
286 | if (!strcmp(name, "DEVNO")) |
287 | dev->bid_devno = STRTOULL(value, 0, 0); |
288 | else if (!strcmp(name, "PRI")) |
289 | dev->bid_pri = strtol(value, 0, 0); |
290 | else if (!strcmp(name, "TIME")) |
291 | /* FIXME: need to parse a long long eventually */ |
292 | dev->bid_time = strtol(value, 0, 0); |
293 | else |
294 | ret = blkid_set_tag(dev, name, value, strlen(value)); |
295 | |
296 | DBG(DEBUG_READ, printf(" tag: %s=\"%s\"\n", name, value)); |
297 | |
298 | return ret < 0 ? ret : 1; |
299 | } |
300 | |
301 | /* |
302 | * Parse a single line of data, and return a newly allocated dev struct. |
303 | * Add the new device to the cache struct, if one was read. |
304 | * |
305 | * Lines are of the form <device [TAG="value" ...]>/dev/foo</device> |
306 | * |
307 | * Returns -ve value on error. |
308 | * Returns 0 otherwise. |
309 | * If a valid device was read, *dev_p is non-NULL, otherwise it is NULL |
310 | * (e.g. comment lines, unknown XML content, etc). |
311 | */ |
312 | static int blkid_parse_line(blkid_cache cache, blkid_dev *dev_p, char *cp) |
313 | { |
314 | blkid_dev dev; |
315 | int ret; |
316 | |
317 | if (!cache || !dev_p) |
318 | return -BLKID_ERR_PARAM; |
319 | |
320 | *dev_p = NULL; |
321 | |
322 | DBG(DEBUG_READ, printf("line: %s\n", cp)); |
323 | |
324 | if ((ret = parse_dev(cache, dev_p, &cp)) <= 0) |
325 | return ret; |
326 | |
327 | dev = *dev_p; |
328 | |
329 | while ((ret = parse_tag(cache, dev, &cp)) > 0) { |
330 | ; |
331 | } |
332 | |
333 | if (dev->bid_type == NULL) { |
334 | DBG(DEBUG_READ, |
335 | printf("blkid: device %s has no TYPE\n",dev->bid_name)); |
336 | blkid_free_dev(dev); |
337 | } |
338 | |
339 | DBG(DEBUG_READ, blkid_debug_dump_dev(dev)); |
340 | |
341 | return ret; |
342 | } |
343 | |
344 | /* |
345 | * Parse the specified filename, and return the data in the supplied or |
346 | * a newly allocated cache struct. If the file doesn't exist, return a |
347 | * new empty cache struct. |
348 | */ |
349 | void blkid_read_cache(blkid_cache cache) |
350 | { |
351 | FILE *file; |
352 | char buf[4096]; |
353 | int fd, lineno = 0; |
354 | struct stat st; |
355 | |
356 | if (!cache) |
357 | return; |
358 | |
359 | /* |
360 | * If the file doesn't exist, then we just return an empty |
361 | * struct so that the cache can be populated. |
362 | */ |
363 | if ((fd = open(cache->bic_filename, O_RDONLY)) < 0) |
364 | return; |
365 | if (fstat(fd, &st) < 0) |
366 | goto errout; |
367 | if ((st.st_mtime == cache->bic_ftime) || |
368 | (cache->bic_flags & BLKID_BIC_FL_CHANGED)) { |
369 | DBG(DEBUG_CACHE, printf("skipping re-read of %s\n", |
370 | cache->bic_filename)); |
371 | goto errout; |
372 | } |
373 | |
374 | DBG(DEBUG_CACHE, printf("reading cache file %s\n", |
375 | cache->bic_filename)); |
376 | |
377 | file = xfdopen_for_read(fd); |
378 | |
379 | while (fgets(buf, sizeof(buf), file)) { |
380 | blkid_dev dev; |
381 | unsigned int end; |
382 | |
383 | lineno++; |
384 | if (buf[0] == 0) |
385 | continue; |
386 | end = strlen(buf) - 1; |
387 | /* Continue reading next line if it ends with a backslash */ |
388 | while (buf[end] == '\\' && end < sizeof(buf) - 2 && |
389 | fgets(buf + end, sizeof(buf) - end, file)) { |
390 | end = strlen(buf) - 1; |
391 | lineno++; |
392 | } |
393 | |
394 | if (blkid_parse_line(cache, &dev, buf) < 0) { |
395 | DBG(DEBUG_READ, |
396 | printf("blkid: bad format on line %d\n", lineno)); |
397 | continue; |
398 | } |
399 | } |
400 | fclose(file); |
401 | |
402 | /* |
403 | * Initially we do not need to write out the cache file. |
404 | */ |
405 | cache->bic_flags &= ~BLKID_BIC_FL_CHANGED; |
406 | cache->bic_ftime = st.st_mtime; |
407 | |
408 | return; |
409 | errout: |
410 | close(fd); |
411 | } |
412 | |
413 | #ifdef TEST_PROGRAM |
414 | static void debug_dump_dev(blkid_dev dev) |
415 | { |
416 | struct list_head *p; |
417 | |
418 | if (!dev) { |
419 | printf(" dev: NULL\n"); |
420 | return; |
421 | } |
422 | |
423 | printf(" dev: name = %s\n", dev->bid_name); |
424 | printf(" dev: DEVNO=\"0x%0llx\"\n", dev->bid_devno); |
425 | printf(" dev: TIME=\"%lu\"\n", dev->bid_time); |
426 | printf(" dev: PRI=\"%d\"\n", dev->bid_pri); |
427 | printf(" dev: flags = 0x%08X\n", dev->bid_flags); |
428 | |
429 | list_for_each(p, &dev->bid_tags) { |
430 | blkid_tag tag = list_entry(p, struct blkid_struct_tag, bit_tags); |
431 | if (tag) |
432 | printf(" tag: %s=\"%s\"\n", tag->bit_name, |
433 | tag->bit_val); |
434 | else |
435 | printf(" tag: NULL\n"); |
436 | } |
437 | bb_putchar('\n'); |
438 | } |
439 | |
440 | int main(int argc, char**argv) |
441 | { |
442 | blkid_cache cache = NULL; |
443 | int ret; |
444 | |
445 | blkid_debug_mask = DEBUG_ALL; |
446 | if (argc > 2) { |
447 | fprintf(stderr, "Usage: %s [filename]\n" |
448 | "Test parsing of the cache (filename)\n", argv[0]); |
449 | exit(1); |
450 | } |
451 | if ((ret = blkid_get_cache(&cache, argv[1])) < 0) |
452 | fprintf(stderr, "error %d reading cache file %s\n", ret, |
453 | argv[1] ? argv[1] : BLKID_CACHE_FILE); |
454 | |
455 | blkid_put_cache(cache); |
456 | |
457 | return ret; |
458 | } |
459 | #endif |