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authorbigbiff bigbiff <bigbiff@teamw.in>2013-02-23 02:55:50 +0100
committerbigbiff bigbiff <bigbiff@teamw.in>2013-02-25 15:06:46 +0100
commite60683a0d553b6488c564863f4e48954944fb0f8 (patch)
tree9364f97cb88b7c1359f5f06dfb32150a78168c31 /libblkid/save.c
parentFix building of updater for 4.2 environment (diff)
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Diffstat (limited to 'libblkid/save.c')
-rw-r--r--libblkid/save.c227
1 files changed, 227 insertions, 0 deletions
diff --git a/libblkid/save.c b/libblkid/save.c
new file mode 100644
index 000000000..c94cc2a82
--- /dev/null
+++ b/libblkid/save.c
@@ -0,0 +1,227 @@
+/*
+ * 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 "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.%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);
+ 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;
+ 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(DEBUG_SAVE, printf("skipping cache file write\n"));
+ 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(DEBUG_SAVE,
+ printf("can't create %s directory for cache file\n",
+ 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(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) {
+ if (fchmod(fd, 0644) != 0)
+ DBG(DEBUG_SAVE, printf("%s: fchmod failed\n", filename));
+ else if ((file = fdopen(fd, "w")))
+ opened = tmp;
+ if (!file)
+ close(fd);
+ }
+ }
+ }
+
+ 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 || (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;
+ }
+
+ 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);
+ }
+ if (rename(opened, filename)) {
+ ret = errno;
+ DBG(DEBUG_SAVE,
+ printf("can't rename %s to %s\n",
+ opened, filename));
+ } else {
+ DBG(DEBUG_SAVE,
+ printf("moved temp cache %s\n", 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(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