| /* |
| * 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 ? |
| dev->bid_type : "(null)")); |
| |
| fprintf(file, |
| "<device DEVNO=\"0x%04lx\" TIME=\"%ld\"", |
| (unsigned long) dev->bid_devno, (long) 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 = malloc(strlen(filename) + 8); |
| if (tmp) { |
| 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 = malloc(strlen(filename) + 5); |
| if (backup) { |
| sprintf(backup, "%s.old", filename); |
| unlink(backup); |
| if (link(filename, backup)) { |
| DBG(DEBUG_SAVE, |
| printf("can't link %s to %s\n", |
| filename, backup)); |
| } |
| free(backup); |
| } |
| rename(opened, filename); |
| DBG(DEBUG_SAVE, |
| printf("moved temp cache %s\n", opened)); |
| } |
| } |
| |
| errout: |
| free(tmp); |
| return ret; |
| } |
| |
| #ifdef TEST_PROGRAM |
| 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 loading/saving a cache (filename)\n", argv[0]); |
| exit(1); |
| } |
| |
| if ((ret = blkid_get_cache(&cache, "/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 |