source: MondoRescue/branches/stable/mindi-busybox/e2fsprogs/blkid/save.c @ 821

Last change on this file since 821 was 821, checked in by Bruno Cornec, 13 years ago

Addition of busybox 1.2.1 as a mindi-busybox new package
This should avoid delivering binary files in mindi not built there (Fedora and Debian are quite serious about that)

File size: 4.0 KB
Line 
1/*
2 * save.c - write the cache struct to disk
3 *
4 * Copyright (C) 2001 by Andreas Dilger
5 * Copyright (C) 2003 Theodore Ts'o
6 *
7 * %Begin-Header%
8 * This file may be redistributed under the terms of the
9 * GNU Lesser General Public License.
10 * %End-Header%
11 */
12
13#include <stdio.h>
14#include <string.h>
15#include <stdlib.h>
16#include <unistd.h>
17#include <sys/types.h>
18#ifdef HAVE_SYS_STAT_H
19#include <sys/stat.h>
20#endif
21#ifdef HAVE_SYS_MKDEV_H
22#include <sys/mkdev.h>
23#endif
24#ifdef HAVE_ERRNO_H
25#include <errno.h>
26#endif
27#include "blkidP.h"
28
29static int save_dev(blkid_dev dev, FILE *file)
30{
31    struct list_head *p;
32
33    if (!dev || dev->bid_name[0] != '/')
34        return 0;
35
36    DBG(DEBUG_SAVE,
37        printf("device %s, type %s\n", dev->bid_name, dev->bid_type));
38
39    fprintf(file,
40        "<device DEVNO=\"0x%04lx\" TIME=\"%lu\"",
41        (unsigned long) dev->bid_devno, dev->bid_time);
42    if (dev->bid_pri)
43        fprintf(file, " PRI=\"%d\"", dev->bid_pri);
44    list_for_each(p, &dev->bid_tags) {
45        blkid_tag tag = list_entry(p, struct blkid_struct_tag, bit_tags);
46        fprintf(file, " %s=\"%s\"", tag->bit_name,tag->bit_val);
47    }
48    fprintf(file, ">%s</device>\n", dev->bid_name);
49
50    return 0;
51}
52
53/*
54 * Write out the cache struct to the cache file on disk.
55 */
56int blkid_flush_cache(blkid_cache cache)
57{
58    struct list_head *p;
59    char *tmp = NULL;
60    const char *opened = NULL;
61    const char *filename;
62    FILE *file = NULL;
63    int fd, ret = 0;
64    struct stat st;
65
66    if (!cache)
67        return -BLKID_ERR_PARAM;
68
69    if (list_empty(&cache->bic_devs) ||
70        !(cache->bic_flags & BLKID_BIC_FL_CHANGED)) {
71        DBG(DEBUG_SAVE, printf("skipping cache file write\n"));
72        return 0;
73    }
74
75    filename = cache->bic_filename ? cache->bic_filename: BLKID_CACHE_FILE;
76
77    /* If we can't write to the cache file, then don't even try */
78    if (((ret = stat(filename, &st)) < 0 && errno != ENOENT) ||
79        (ret == 0 && access(filename, W_OK) < 0)) {
80        DBG(DEBUG_SAVE,
81            printf("can't write to cache file %s\n", filename));
82        return 0;
83    }
84
85    /*
86     * Try and create a temporary file in the same directory so
87     * that in case of error we don't overwrite the cache file.
88     * If the cache file doesn't yet exist, it isn't a regular
89     * file (e.g. /dev/null or a socket), or we couldn't create
90     * a temporary file then we open it directly.
91     */
92    if (ret == 0 && S_ISREG(st.st_mode)) {
93        tmp = xmalloc(strlen(filename) + 8);
94        sprintf(tmp, "%s-XXXXXX", filename);
95        fd = mkstemp(tmp);
96        if (fd >= 0) {
97            file = fdopen(fd, "w");
98            opened = tmp;
99        }
100        fchmod(fd, 0644);
101    }
102
103    if (!file) {
104        file = fopen(filename, "w");
105        opened = filename;
106    }
107
108    DBG(DEBUG_SAVE,
109        printf("writing cache file %s (really %s)\n",
110           filename, opened));
111
112    if (!file) {
113        ret = errno;
114        goto errout;
115    }
116
117    list_for_each(p, &cache->bic_devs) {
118        blkid_dev dev = list_entry(p, struct blkid_struct_dev, bid_devs);
119        if (!dev->bid_type)
120            continue;
121        if ((ret = save_dev(dev, file)) < 0)
122            break;
123    }
124
125    if (ret >= 0) {
126        cache->bic_flags &= ~BLKID_BIC_FL_CHANGED;
127        ret = 1;
128    }
129
130    fclose(file);
131    if (opened != filename) {
132        if (ret < 0) {
133            unlink(opened);
134            DBG(DEBUG_SAVE,
135                printf("unlinked temp cache %s\n", opened));
136        } else {
137            char *backup;
138
139            backup = xmalloc(strlen(filename) + 5);
140            sprintf(backup, "%s.old", filename);
141            unlink(backup);
142            link(filename, backup);
143            free(backup);
144            rename(opened, filename);
145            DBG(DEBUG_SAVE,
146                printf("moved temp cache %s\n", opened));
147        }
148    }
149
150errout:
151    free(tmp);
152    return ret;
153}
154
155#ifdef TEST_PROGRAM
156int main(int argc, char **argv)
157{
158    blkid_cache cache = NULL;
159    int ret;
160
161    blkid_debug_mask = DEBUG_ALL;
162    if (argc > 2) {
163        fprintf(stderr, "Usage: %s [filename]\n"
164            "Test loading/saving a cache (filename)\n", argv[0]);
165        exit(1);
166    }
167
168    if ((ret = blkid_get_cache(&cache, bb_dev_null)) != 0) {
169        fprintf(stderr, "%s: error creating cache (%d)\n",
170            argv[0], ret);
171        exit(1);
172    }
173    if ((ret = blkid_probe_all(cache)) < 0) {
174        fprintf(stderr, "error (%d) probing devices\n", ret);
175        exit(1);
176    }
177    cache->bic_filename = blkid_strdup(argv[1]);
178
179    if ((ret = blkid_flush_cache(cache)) < 0) {
180        fprintf(stderr, "error (%d) saving cache\n", ret);
181        exit(1);
182    }
183
184    blkid_put_cache(cache);
185
186    return ret;
187}
188#endif
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