/* vi: set sw=4 ts=4: *//* * save.c - write the cache struct to disk * * Copyright (C) 2001 by Andreas Dilger * Copyright (C) 2003 Theodore Ts'o * * %Begin-Header% * This file may be redistributed under the terms of the * GNU Lesser General Public License. * %End-Header% */#include <stdio.h>#include <string.h>#include <stdlib.h>#include <unistd.h>#include <sys/types.h>#ifdef HAVE_SYS_STAT_H#include <sys/stat.h>#endif#ifdef HAVE_SYS_MKDEV_H#include <sys/mkdev.h>#endif#ifdef HAVE_ERRNO_H#include <errno.h>#endif#include "blkidP.h"static int save_dev(blkid_dev dev, FILE *file){	struct list_head *p;	if (!dev || dev->bid_name[0] != '/')		return 0;	DBG(DEBUG_SAVE,	    printf("device %s, type %s\n", dev->bid_name, dev->bid_type));	fprintf(file,		"<device DEVNO=\"0x%04lx\" TIME=\"%lu\"",		(unsigned long) dev->bid_devno, dev->bid_time);	if (dev->bid_pri)		fprintf(file, " PRI=\"%d\"", dev->bid_pri);	list_for_each(p, &dev->bid_tags) {		blkid_tag tag = list_entry(p, struct blkid_struct_tag, bit_tags);		fprintf(file, " %s=\"%s\"", tag->bit_name,tag->bit_val);	}	fprintf(file, ">%s</device>\n", dev->bid_name);	return 0;}/* * Write out the cache struct to the cache file on disk. */int blkid_flush_cache(blkid_cache cache){	struct list_head *p;	char *tmp = NULL;	const char *opened = NULL;	const char *filename;	FILE *file = NULL;	int fd, ret = 0;	struct stat st;	if (!cache)		return -BLKID_ERR_PARAM;	if (list_empty(&cache->bic_devs) ||	    !(cache->bic_flags & BLKID_BIC_FL_CHANGED)) {		DBG(DEBUG_SAVE, printf("skipping cache file write\n"));		return 0;	}	filename = cache->bic_filename ? cache->bic_filename: BLKID_CACHE_FILE;	/* If we can't write to the cache file, then don't even try */	if (((ret = stat(filename, &st)) < 0 && errno != ENOENT) ||	    (ret == 0 && access(filename, W_OK) < 0)) {		DBG(DEBUG_SAVE,		    printf("can't write to cache file %s\n", filename));		return 0;	}	/*	 * Try and create a temporary file in the same directory so	 * that in case of error we don't overwrite the cache file.	 * If the cache file doesn't yet exist, it isn't a regular	 * file (e.g. /dev/null or a socket), or we couldn't create	 * a temporary file then we open it directly.	 */	if (ret == 0 && S_ISREG(st.st_mode)) {		tmp = xmalloc(strlen(filename) + 8);		sprintf(tmp, "%s-XXXXXX", filename);		fd = mkstemp(tmp);		if (fd >= 0) {			file = fdopen(fd, "w");			opened = tmp;		}		fchmod(fd, 0644);	}	if (!file) {		file = fopen(filename, "w");		opened = filename;	}	DBG(DEBUG_SAVE,	    printf("writing cache file %s (really %s)\n",		   filename, opened));	if (!file) {		ret = errno;		goto errout;	}	list_for_each(p, &cache->bic_devs) {		blkid_dev dev = list_entry(p, struct blkid_struct_dev, bid_devs);		if (!dev->bid_type)			continue;		if ((ret = save_dev(dev, file)) < 0)			break;	}	if (ret >= 0) {		cache->bic_flags &= ~BLKID_BIC_FL_CHANGED;		ret = 1;	}	fclose(file);	if (opened != filename) {		if (ret < 0) {			unlink(opened);			DBG(DEBUG_SAVE,			    printf("unlinked temp cache %s\n", opened));		} else {			char *backup;			backup = xmalloc(strlen(filename) + 5);			sprintf(backup, "%s.old", filename);			unlink(backup);			link(filename, backup);			free(backup);			rename(opened, filename);			DBG(DEBUG_SAVE,			    printf("moved temp cache %s\n", opened));		}	}errout:	free(tmp);	return ret;}#ifdef TEST_PROGRAMint 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 loading/saving a cache (filename)\n", argv[0]);		exit(1);	}	if ((ret = blkid_get_cache(&cache, bb_dev_null)) != 0) {		fprintf(stderr, "%s: error creating cache (%d)\n",			argv[0], ret);		exit(1);	}	if ((ret = blkid_probe_all(cache)) < 0) {		fprintf(stderr, "error (%d) probing devices\n", ret);		exit(1);	}	cache->bic_filename = blkid_strdup(argv[1]);	if ((ret = blkid_flush_cache(cache)) < 0) {		fprintf(stderr, "error (%d) saving cache\n", ret);		exit(1);	}	blkid_put_cache(cache);	return ret;}#endif