/* 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);}#ifdef TEST_PROGRAMstatic 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