| /* |
| * read.c - read the blkid cache from disk, to avoid scanning all devices |
| * |
| * Copyright (C) 2001, 2003 Theodore Y. Ts'o |
| * Copyright (C) 2001 Andreas Dilger |
| * |
| * %Begin-Header% |
| * This file may be redistributed under the terms of the |
| * GNU Lesser General Public License. |
| * %End-Header% |
| */ |
| |
| |
| #include <stdio.h> |
| #include <ctype.h> |
| #include <string.h> |
| #include <time.h> |
| #include <sys/types.h> |
| #include <sys/stat.h> |
| #include <fcntl.h> |
| #include <unistd.h> |
| #ifdef HAVE_ERRNO_H |
| #include <errno.h> |
| #endif |
| |
| #include "blkidP.h" |
| |
| #ifdef HAVE_STDLIB_H |
| # ifndef _XOPEN_SOURCE |
| # define _XOPEN_SOURCE 600 /* for inclusion of strtoull */ |
| # endif |
| # include <stdlib.h> |
| #endif |
| |
| #ifdef HAVE_STRTOULL |
| #define STRTOULL strtoull /* defined in stdlib.h if you try hard enough */ |
| #else |
| /* FIXME: need to support real strtoull here */ |
| #define STRTOULL strtoul |
| #endif |
| |
| #ifdef TEST_PROGRAM |
| #define blkid_debug_dump_dev(dev) (debug_dump_dev(dev)) |
| static void debug_dump_dev(blkid_dev dev); |
| #endif |
| |
| /* |
| * File format: |
| * |
| * <device [<NAME="value"> ...]>device_name</device> |
| * |
| * The following tags are required for each entry: |
| * <ID="id"> unique (within this file) ID number of this device |
| * <TIME="sec.usec"> (time_t and suseconds_t) time this entry was last |
| * read from disk |
| * <TYPE="type"> (detected) type of filesystem/data for this partition |
| * |
| * The following tags may be present, depending on the device contents |
| * <LABEL="label"> (user supplied) label (volume name, etc) |
| * <UUID="uuid"> (generated) universally unique identifier (serial no) |
| */ |
| |
| static char *skip_over_blank(char *cp) |
| { |
| while (*cp && isspace(*cp)) |
| cp++; |
| return cp; |
| } |
| |
| static char *skip_over_word(char *cp) |
| { |
| char ch; |
| |
| while ((ch = *cp)) { |
| /* If we see a backslash, skip the next character */ |
| if (ch == '\\') { |
| cp++; |
| if (*cp == '\0') |
| break; |
| cp++; |
| continue; |
| } |
| if (isspace(ch) || ch == '<' || ch == '>') |
| break; |
| cp++; |
| } |
| return cp; |
| } |
| |
| static char *strip_line(char *line) |
| { |
| char *p; |
| |
| line = skip_over_blank(line); |
| |
| p = line + strlen(line) - 1; |
| |
| while (*line) { |
| if (isspace(*p)) |
| *p-- = '\0'; |
| else |
| break; |
| } |
| |
| return line; |
| } |
| |
| #if 0 |
| static char *parse_word(char **buf) |
| { |
| char *word, *next; |
| |
| word = *buf; |
| if (*word == '\0') |
| return NULL; |
| |
| word = skip_over_blank(word); |
| next = skip_over_word(word); |
| if (*next) { |
| char *end = next - 1; |
| if (*end == '"' || *end == '\'') |
| *end = '\0'; |
| *next++ = '\0'; |
| } |
| *buf = next; |
| |
| if (*word == '"' || *word == '\'') |
| word++; |
| return word; |
| } |
| #endif |
| |
| /* |
| * Start parsing a new line from the cache. |
| * |
| * line starts with "<device" return 1 -> continue parsing line |
| * line starts with "<foo", empty, or # return 0 -> skip line |
| * line starts with other, return -BLKID_ERR_CACHE -> error |
| */ |
| static int parse_start(char **cp) |
| { |
| char *p; |
| |
| p = strip_line(*cp); |
| |
| /* Skip comment or blank lines. We can't just NUL the first '#' char, |
| * in case it is inside quotes, or escaped. |
| */ |
| if (*p == '\0' || *p == '#') |
| return 0; |
| |
| if (!strncmp(p, "<device", 7)) { |
| DBG(DEBUG_READ, printf("found device header: %8s\n", p)); |
| p += 7; |
| |
| *cp = p; |
| return 1; |
| } |
| |
| if (*p == '<') |
| return 0; |
| |
| return -BLKID_ERR_CACHE; |
| } |
| |
| /* Consume the remaining XML on the line (cosmetic only) */ |
| static int parse_end(char **cp) |
| { |
| *cp = skip_over_blank(*cp); |
| |
| if (!strncmp(*cp, "</device>", 9)) { |
| DBG(DEBUG_READ, printf("found device trailer %9s\n", *cp)); |
| *cp += 9; |
| return 0; |
| } |
| |
| return -BLKID_ERR_CACHE; |
| } |
| |
| /* |
| * Allocate a new device struct with device name filled in. Will handle |
| * finding the device on lines of the form: |
| * <device foo=bar>devname</device> |
| * <device>devname<foo>bar</foo></device> |
| */ |
| static int parse_dev(blkid_cache cache, blkid_dev *dev, char **cp) |
| { |
| char *start, *tmp, *end, *name; |
| int ret; |
| |
| if ((ret = parse_start(cp)) <= 0) |
| return ret; |
| |
| start = tmp = strchr(*cp, '>'); |
| if (!start) { |
| DBG(DEBUG_READ, |
| printf("blkid: short line parsing dev: %s\n", *cp)); |
| return -BLKID_ERR_CACHE; |
| } |
| start = skip_over_blank(start + 1); |
| end = skip_over_word(start); |
| |
| DBG(DEBUG_READ, printf("device should be %*s\n", |
| (int)(end - start), start)); |
| |
| if (**cp == '>') |
| *cp = end; |
| else |
| (*cp)++; |
| |
| *tmp = '\0'; |
| |
| if (!(tmp = strrchr(end, '<')) || parse_end(&tmp) < 0) { |
| DBG(DEBUG_READ, |
| printf("blkid: missing </device> ending: %s\n", end)); |
| } else if (tmp) |
| *tmp = '\0'; |
| |
| if (end - start <= 1) { |
| DBG(DEBUG_READ, printf("blkid: empty device name: %s\n", *cp)); |
| return -BLKID_ERR_CACHE; |
| } |
| |
| name = blkid_strndup(start, end-start); |
| if (name == NULL) |
| return -BLKID_ERR_MEM; |
| |
| DBG(DEBUG_READ, printf("found dev %s\n", name)); |
| |
| if (!(*dev = blkid_get_dev(cache, name, BLKID_DEV_CREATE))) { |
| free(name); |
| return -BLKID_ERR_MEM; |
| } |
| |
| free(name); |
| return 1; |
| } |
| |
| /* |
| * Extract a tag of the form NAME="value" from the line. |
| */ |
| static int parse_token(char **name, char **value, char **cp) |
| { |
| char *end; |
| |
| if (!name || !value || !cp) |
| return -BLKID_ERR_PARAM; |
| |
| if (!(*value = strchr(*cp, '='))) |
| return 0; |
| |
| **value = '\0'; |
| *name = strip_line(*cp); |
| *value = skip_over_blank(*value + 1); |
| |
| if (**value == '"') { |
| end = strchr(*value + 1, '"'); |
| if (!end) { |
| DBG(DEBUG_READ, |
| printf("unbalanced quotes at: %s\n", *value)); |
| *cp = *value; |
| return -BLKID_ERR_CACHE; |
| } |
| (*value)++; |
| *end = '\0'; |
| end++; |
| } else { |
| end = skip_over_word(*value); |
| if (*end) { |
| *end = '\0'; |
| end++; |
| } |
| } |
| *cp = end; |
| |
| return 1; |
| } |
| |
| /* |
| * Extract a tag of the form <NAME>value</NAME> from the line. |
| */ |
| /* |
| static int parse_xml(char **name, char **value, char **cp) |
| { |
| char *end; |
| |
| if (!name || !value || !cp) |
| return -BLKID_ERR_PARAM; |
| |
| *name = strip_line(*cp); |
| |
| if ((*name)[0] != '<' || (*name)[1] == '/') |
| return 0; |
| |
| FIXME: finish this. |
| } |
| */ |
| |
| /* |
| * Extract a tag from the line. |
| * |
| * Return 1 if a valid tag was found. |
| * Return 0 if no tag found. |
| * Return -ve error code. |
| */ |
| static int parse_tag(blkid_cache cache, blkid_dev dev, char **cp) |
| { |
| char *name = NULL; |
| char *value = NULL; |
| int ret; |
| |
| if (!cache || !dev) |
| return -BLKID_ERR_PARAM; |
| |
| if ((ret = parse_token(&name, &value, cp)) <= 0 /* && |
| (ret = parse_xml(&name, &value, cp)) <= 0 */) |
| return ret; |
| |
| /* Some tags are stored directly in the device struct */ |
| if (!strcmp(name, "DEVNO")) |
| dev->bid_devno = STRTOULL(value, 0, 0); |
| else if (!strcmp(name, "PRI")) |
| dev->bid_pri = strtol(value, 0, 0); |
| else if (!strcmp(name, "TIME")) { |
| char *end = NULL; |
| dev->bid_time = STRTOULL(value, &end, 0); |
| if (end && *end == '.') |
| dev->bid_utime = STRTOULL(end + 1, 0, 0); |
| } else |
| ret = blkid_set_tag(dev, name, value, strlen(value)); |
| |
| DBG(DEBUG_READ, printf(" tag: %s=\"%s\"\n", name, value)); |
| |
| return ret < 0 ? ret : 1; |
| } |
| |
| /* |
| * Parse a single line of data, and return a newly allocated dev struct. |
| * Add the new device to the cache struct, if one was read. |
| * |
| * Lines are of the form <device [TAG="value" ...]>/dev/foo</device> |
| * |
| * Returns -ve value on error. |
| * Returns 0 otherwise. |
| * If a valid device was read, *dev_p is non-NULL, otherwise it is NULL |
| * (e.g. comment lines, unknown XML content, etc). |
| */ |
| static int blkid_parse_line(blkid_cache cache, blkid_dev *dev_p, char *cp) |
| { |
| blkid_dev dev; |
| int ret; |
| |
| if (!cache || !dev_p) |
| return -BLKID_ERR_PARAM; |
| |
| *dev_p = NULL; |
| |
| DBG(DEBUG_READ, printf("line: %s\n", cp)); |
| |
| if ((ret = parse_dev(cache, dev_p, &cp)) <= 0) |
| return ret; |
| |
| dev = *dev_p; |
| |
| while ((ret = parse_tag(cache, dev, &cp)) > 0) { |
| ; |
| } |
| |
| if (dev->bid_type == NULL) { |
| DBG(DEBUG_READ, |
| printf("blkid: device %s has no TYPE\n",dev->bid_name)); |
| blkid_free_dev(dev); |
| goto done; |
| } |
| |
| DBG(DEBUG_READ, blkid_debug_dump_dev(dev)); |
| |
| done: |
| return ret; |
| } |
| |
| /* |
| * Parse the specified filename, and return the data in the supplied or |
| * a newly allocated cache struct. If the file doesn't exist, return a |
| * new empty cache struct. |
| */ |
| void blkid_read_cache(blkid_cache cache) |
| { |
| FILE *file; |
| char buf[4096]; |
| int fd, lineno = 0; |
| struct stat st; |
| |
| if (!cache) |
| return; |
| |
| /* |
| * If the file doesn't exist, then we just return an empty |
| * struct so that the cache can be populated. |
| */ |
| if ((fd = open(cache->bic_filename, O_RDONLY)) < 0) |
| return; |
| if (fstat(fd, &st) < 0) |
| goto errout; |
| if ((st.st_mtime == cache->bic_ftime) || |
| (cache->bic_flags & BLKID_BIC_FL_CHANGED)) { |
| DBG(DEBUG_CACHE, printf("skipping re-read of %s\n", |
| cache->bic_filename)); |
| goto errout; |
| } |
| |
| DBG(DEBUG_CACHE, printf("reading cache file %s\n", |
| cache->bic_filename)); |
| |
| file = fdopen(fd, "r"); |
| if (!file) |
| goto errout; |
| |
| while (fgets(buf, sizeof(buf), file)) { |
| blkid_dev dev; |
| unsigned int end; |
| |
| lineno++; |
| if (buf[0] == 0) |
| continue; |
| end = strlen(buf) - 1; |
| /* Continue reading next line if it ends with a backslash */ |
| while (end < (sizeof(buf) - 2) && buf[end] == '\\' && |
| fgets(buf + end, sizeof(buf) - end, file)) { |
| end = strlen(buf) - 1; |
| lineno++; |
| } |
| |
| if (blkid_parse_line(cache, &dev, buf) < 0) { |
| DBG(DEBUG_READ, |
| printf("blkid: bad format on line %d\n", lineno)); |
| continue; |
| } |
| } |
| fclose(file); |
| |
| /* |
| * Initially we do not need to write out the cache file. |
| */ |
| cache->bic_flags &= ~BLKID_BIC_FL_CHANGED; |
| cache->bic_ftime = st.st_mtime; |
| |
| return; |
| errout: |
| close(fd); |
| return; |
| } |
| |
| #ifdef TEST_PROGRAM |
| static void debug_dump_dev(blkid_dev dev) |
| { |
| struct list_head *p; |
| |
| if (!dev) { |
| printf(" dev: NULL\n"); |
| return; |
| } |
| |
| printf(" dev: name = %s\n", dev->bid_name); |
| printf(" dev: DEVNO=\"0x%0llx\"\n", (long long)dev->bid_devno); |
| printf(" dev: TIME=\"%ld.%ld\"\n", (long)dev->bid_time, (long)dev->bid_utime); |
| printf(" dev: PRI=\"%d\"\n", dev->bid_pri); |
| printf(" dev: flags = 0x%08X\n", dev->bid_flags); |
| |
| list_for_each(p, &dev->bid_tags) { |
| blkid_tag tag = list_entry(p, struct blkid_struct_tag, bit_tags); |
| if (tag) |
| printf(" tag: %s=\"%s\"\n", tag->bit_name, |
| tag->bit_val); |
| else |
| printf(" tag: NULL\n"); |
| } |
| printf("\n"); |
| } |
| |
| int main(int argc, char**argv) |
| { |
| blkid_cache cache = NULL; |
| int ret; |
| |
| blkid_init_debug(DEBUG_ALL); |
| if (argc > 2) { |
| fprintf(stderr, "Usage: %s [filename]\n" |
| "Test parsing of the cache (filename)\n", argv[0]); |
| exit(1); |
| } |
| if ((ret = blkid_get_cache(&cache, argv[1])) < 0) |
| fprintf(stderr, "error %d reading cache file %s\n", ret, |
| argv[1] ? argv[1] : blkid_get_cache_filename(NULL)); |
| |
| blkid_put_cache(cache); |
| |
| return ret; |
| } |
| #endif |