diff options
Diffstat (limited to 'e2fsprogs/old_e2fsprogs/blkid/read.c')
-rw-r--r-- | e2fsprogs/old_e2fsprogs/blkid/read.c | 462 |
1 files changed, 462 insertions, 0 deletions
diff --git a/e2fsprogs/old_e2fsprogs/blkid/read.c b/e2fsprogs/old_e2fsprogs/blkid/read.c new file mode 100644 index 0000000..bb02a2e --- /dev/null +++ b/e2fsprogs/old_e2fsprogs/blkid/read.c @@ -0,0 +1,462 @@ +/* vi: set sw=4 ts=4: */ +/* + * 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> +#include <errno.h> + +#include "blkidP.h" +#include "../uuid/uuid.h" + +#ifdef HAVE_STRTOULL +#define __USE_ISOC9X +#define STRTOULL strtoull /* defined in stdlib.h if you try hard enough */ +#else +/* FIXME: need to support real strtoull here */ +#define STRTOULL strtoul +#endif + +#include <stdlib.h> + +#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="time"> (ascii time_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; +} + +/* + * 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", 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))) + 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; + char *value; + 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")) + /* FIXME: need to parse a long long eventually */ + dev->bid_time = strtol(value, 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); + } + + DBG(DEBUG_READ, blkid_debug_dump_dev(dev)); + + 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 (buf[end] == '\\' && end < sizeof(buf) - 2 && + 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", dev->bid_devno); + printf(" dev: TIME=\"%lu\"\n", dev->bid_time); + 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"); + } + puts(""); +} + +int main(int argc, char**argv) +{ + blkid_cache cache = NULL; + int ret; + + blkid_debug_mask = 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_CACHE_FILE); + + blkid_put_cache(cache); + + return ret; +} +#endif |