File: save.c

package info (click to toggle)
util-linux 2.25.2-6
  • links: PTS, VCS
  • area: main
  • in suites: jessie, jessie-kfreebsd
  • size: 60,764 kB
  • ctags: 11,189
  • sloc: ansic: 103,273; sh: 18,345; makefile: 322; python: 316; xml: 232; csh: 37; sed: 16
file content (244 lines) | stat: -rw-r--r-- 5,655 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
/*
 * 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_ERRNO_H
#include <errno.h>
#endif

#include "closestream.h"

#include "blkidP.h"


static void save_quoted(const char *data, FILE *file)
{
	const char *p;

	fputc('"', file);
	for (p = data; p && *p; p++) {
		if ((unsigned char) *p == 0x22 ||		/* " */
		    (unsigned char) *p == 0x5c)			/* \ */
			fputc('\\', file);

		fputc(*p, file);
	}
	fputc('"', file);
}
static int save_dev(blkid_dev dev, FILE *file)
{
	struct list_head *p;

	if (!dev || dev->bid_name[0] != '/')
		return 0;

	DBG(SAVE, ul_debug("device %s, type %s", dev->bid_name, dev->bid_type ?
		   dev->bid_type : "(null)"));

	fprintf(file, "<device DEVNO=\"0x%04lx\" TIME=\"%ld.%ld\"",
			(unsigned long) dev->bid_devno,
			(long) dev->bid_time,
			(long) dev->bid_utime);

	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);

		fputc(' ', file);			/* space between tags */
		fputs(tag->bit_name, file);		/* tag NAME */
		fputc('=', file);			/* separator between NAME and VALUE */
		save_quoted(tag->bit_val, file);	/* tag "VALUE" */
	}
	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;
	char *opened = NULL;
	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(SAVE, ul_debug("skipping cache file write"));
		return 0;
	}

	filename = cache->bic_filename ? cache->bic_filename :
					 blkid_get_cache_filename(NULL);
	if (!filename)
		return -BLKID_ERR_PARAM;

	if (strncmp(filename,
	    BLKID_RUNTIME_DIR "/", sizeof(BLKID_RUNTIME_DIR)) == 0) {

		/* default destination, create the directory if necessary */
		if (stat(BLKID_RUNTIME_DIR, &st)
		    && errno == ENOENT
		    && mkdir(BLKID_RUNTIME_DIR, S_IWUSR|
						S_IRUSR|S_IRGRP|S_IROTH|
						S_IXUSR|S_IXGRP|S_IXOTH) != 0
		    && errno != EEXIST) {
			DBG(SAVE, ul_debug("can't create %s directory for cache file",
					BLKID_RUNTIME_DIR));
			return 0;
		}
	}

	/* 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(SAVE, ul_debug("can't write to cache file %s", 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 = mkostemp(tmp, O_RDWR|O_CREAT|O_EXCL|O_CLOEXEC);
			if (fd >= 0) {
				if (fchmod(fd, 0644) != 0)
					DBG(SAVE, ul_debug("%s: fchmod failed", filename));
				else if ((file = fdopen(fd, "w" UL_CLOEXECSTR)))
					opened = tmp;
				if (!file)
					close(fd);
			}
		}
	}

	if (!file) {
		file = fopen(filename, "w" UL_CLOEXECSTR);
		opened = filename;
	}

	DBG(SAVE, ul_debug("writing cache file %s (really %s)",
		   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 || (dev->bid_flags & BLKID_BID_FL_REMOVABLE))
			continue;
		if ((ret = save_dev(dev, file)) < 0)
			break;
	}

	if (ret >= 0) {
		cache->bic_flags &= ~BLKID_BIC_FL_CHANGED;
		ret = 1;
	}

	if (close_stream(file) != 0)
		DBG(SAVE, ul_debug("write failed: %s", filename));

	if (opened != filename) {
		if (ret < 0) {
			unlink(opened);
			DBG(SAVE, ul_debug("unlinked temp cache %s", opened));
		} else {
			char *backup;

			backup = malloc(strlen(filename) + 5);
			if (backup) {
				sprintf(backup, "%s.old", filename);
				unlink(backup);
				if (link(filename, backup)) {
					DBG(SAVE, ul_debug("can't link %s to %s",
							filename, backup));
				}
				free(backup);
			}
			if (rename(opened, filename)) {
				ret = errno;
				DBG(SAVE, ul_debug("can't rename %s to %s",
						opened, filename));
			} else {
				DBG(SAVE, ul_debug("moved temp cache %s", opened));
			}
		}
	}

errout:
	free(tmp);
	if (filename != cache->bic_filename)
		free(filename);
	return ret;
}

#ifdef TEST_PROGRAM
int main(int argc, char **argv)
{
	blkid_cache cache = NULL;
	int ret;

	blkid_init_debug(BLKID_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 = 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