1 /* vi: set sw=4 ts=4: */
3 * read.c - read the blkid cache from disk, to avoid scanning all devices
5 * Copyright (C) 2001, 2003 Theodore Y. Ts'o
6 * Copyright (C) 2001 Andreas Dilger
9 * This file may be redistributed under the terms of the
10 * GNU Lesser General Public License.
18 #include <sys/types.h>
25 #include "../uuid/uuid.h"
29 #define STRTOULL strtoull /* defined in stdlib.h if you try hard enough */
31 /* FIXME: need to support real strtoull here */
32 #define STRTOULL strtoul
38 #define blkid_debug_dump_dev(dev) (debug_dump_dev(dev))
39 static void debug_dump_dev(blkid_dev dev
);
45 * <device [<NAME="value"> ...]>device_name</device>
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
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)
57 static char *skip_over_blank(char *cp
)
59 while (*cp
&& isspace(*cp
))
64 static char *skip_over_word(char *cp
)
69 /* If we see a backslash, skip the next character */
77 if (isspace(ch
) || ch
== '<' || ch
== '>')
84 static char *strip_line(char *line
)
88 line
= skip_over_blank(line
);
90 p
= line
+ strlen(line
) - 1;
103 * Start parsing a new line from the cache.
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
109 static int parse_start(char **cp
)
115 /* Skip comment or blank lines. We can't just NUL the first '#' char,
116 * in case it is inside quotes, or escaped.
118 if (*p
== '\0' || *p
== '#')
121 if (!strncmp(p
, "<device", 7)) {
122 DBG(DEBUG_READ
, printf("found device header: %8s\n", p
));
132 return -BLKID_ERR_CACHE
;
135 /* Consume the remaining XML on the line (cosmetic only) */
136 static int parse_end(char **cp
)
138 *cp
= skip_over_blank(*cp
);
140 if (!strncmp(*cp
, "</device>", 9)) {
141 DBG(DEBUG_READ
, printf("found device trailer %9s\n", *cp
));
146 return -BLKID_ERR_CACHE
;
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>
155 static int parse_dev(blkid_cache cache
, blkid_dev
*dev
, char **cp
)
157 char *start
, *tmp
, *end
, *name
;
160 if ((ret
= parse_start(cp
)) <= 0)
163 start
= tmp
= strchr(*cp
, '>');
166 printf("blkid: short line parsing dev: %s\n", *cp
));
167 return -BLKID_ERR_CACHE
;
169 start
= skip_over_blank(start
+ 1);
170 end
= skip_over_word(start
);
172 DBG(DEBUG_READ
, printf("device should be %*s\n", end
- start
, start
));
181 if (!(tmp
= strrchr(end
, '<')) || parse_end(&tmp
) < 0) {
183 printf("blkid: missing </device> ending: %s\n", end
));
187 if (end
- start
<= 1) {
188 DBG(DEBUG_READ
, printf("blkid: empty device name: %s\n", *cp
));
189 return -BLKID_ERR_CACHE
;
192 name
= blkid_strndup(start
, end
-start
);
194 return -BLKID_ERR_MEM
;
196 DBG(DEBUG_READ
, printf("found dev %s\n", name
));
198 if (!(*dev
= blkid_get_dev(cache
, name
, BLKID_DEV_CREATE
)))
199 return -BLKID_ERR_MEM
;
206 * Extract a tag of the form NAME="value" from the line.
208 static int parse_token(char **name
, char **value
, char **cp
)
212 if (!name
|| !value
|| !cp
)
213 return -BLKID_ERR_PARAM
;
215 if (!(*value
= strchr(*cp
, '=')))
219 *name
= strip_line(*cp
);
220 *value
= skip_over_blank(*value
+ 1);
222 if (**value
== '"') {
223 end
= strchr(*value
+ 1, '"');
226 printf("unbalanced quotes at: %s\n", *value
));
228 return -BLKID_ERR_CACHE
;
234 end
= skip_over_word(*value
);
246 * Extract a tag of the form <NAME>value</NAME> from the line.
249 static int parse_xml(char **name, char **value, char **cp)
253 if (!name || !value || !cp)
254 return -BLKID_ERR_PARAM;
256 *name = strip_line(*cp);
258 if ((*name)[0] != '<' || (*name)[1] == '/')
266 * Extract a tag from the line.
268 * Return 1 if a valid tag was found.
269 * Return 0 if no tag found.
270 * Return -ve error code.
272 static int parse_tag(blkid_cache cache
, blkid_dev dev
, char **cp
)
279 return -BLKID_ERR_PARAM
;
281 if ((ret
= parse_token(&name
, &value
, cp
)) <= 0 /* &&
282 (ret = parse_xml(&name, &value, cp)) <= 0 */)
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);
294 ret
= blkid_set_tag(dev
, name
, value
, strlen(value
));
296 DBG(DEBUG_READ
, printf(" tag: %s=\"%s\"\n", name
, value
));
298 return ret
< 0 ? ret
: 1;
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.
305 * Lines are of the form <device [TAG="value" ...]>/dev/foo</device>
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).
312 static int blkid_parse_line(blkid_cache cache
, blkid_dev
*dev_p
, char *cp
)
317 if (!cache
|| !dev_p
)
318 return -BLKID_ERR_PARAM
;
322 DBG(DEBUG_READ
, printf("line: %s\n", cp
));
324 if ((ret
= parse_dev(cache
, dev_p
, &cp
)) <= 0)
329 while ((ret
= parse_tag(cache
, dev
, &cp
)) > 0) {
333 if (dev
->bid_type
== NULL
) {
335 printf("blkid: device %s has no TYPE\n",dev
->bid_name
));
339 DBG(DEBUG_READ
, blkid_debug_dump_dev(dev
));
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.
349 void blkid_read_cache(blkid_cache cache
)
360 * If the file doesn't exist, then we just return an empty
361 * struct so that the cache can be populated.
363 if ((fd
= open(cache
->bic_filename
, O_RDONLY
)) < 0)
365 if (fstat(fd
, &st
) < 0)
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
));
374 DBG(DEBUG_CACHE
, printf("reading cache file %s\n",
375 cache
->bic_filename
));
377 file
= fdopen(fd
, "r");
381 while (fgets(buf
, sizeof(buf
), file
)) {
388 end
= strlen(buf
) - 1;
389 /* Continue reading next line if it ends with a backslash */
390 while (buf
[end
] == '\\' && end
< sizeof(buf
) - 2 &&
391 fgets(buf
+ end
, sizeof(buf
) - end
, file
)) {
392 end
= strlen(buf
) - 1;
396 if (blkid_parse_line(cache
, &dev
, buf
) < 0) {
398 printf("blkid: bad format on line %d\n", lineno
));
405 * Initially we do not need to write out the cache file.
407 cache
->bic_flags
&= ~BLKID_BIC_FL_CHANGED
;
408 cache
->bic_ftime
= st
.st_mtime
;
416 static void debug_dump_dev(blkid_dev dev
)
421 printf(" dev: NULL\n");
425 printf(" dev: name = %s\n", dev
->bid_name
);
426 printf(" dev: DEVNO=\"0x%0llx\"\n", dev
->bid_devno
);
427 printf(" dev: TIME=\"%lu\"\n", dev
->bid_time
);
428 printf(" dev: PRI=\"%d\"\n", dev
->bid_pri
);
429 printf(" dev: flags = 0x%08X\n", dev
->bid_flags
);
431 list_for_each(p
, &dev
->bid_tags
) {
432 blkid_tag tag
= list_entry(p
, struct blkid_struct_tag
, bit_tags
);
434 printf(" tag: %s=\"%s\"\n", tag
->bit_name
,
437 printf(" tag: NULL\n");
442 int main(int argc
, char**argv
)
444 blkid_cache cache
= NULL
;
447 blkid_debug_mask
= DEBUG_ALL
;
449 fprintf(stderr
, "Usage: %s [filename]\n"
450 "Test parsing of the cache (filename)\n", argv
[0]);
453 if ((ret
= blkid_get_cache(&cache
, argv
[1])) < 0)
454 fprintf(stderr
, "error %d reading cache file %s\n", ret
,
455 argv
[1] ? argv
[1] : BLKID_CACHE_FILE
);
457 blkid_put_cache(cache
);