diff options
Diffstat (limited to 'lib/loopdev.c')
| -rw-r--r-- | lib/loopdev.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/lib/loopdev.c b/lib/loopdev.c index 11555b0a84..f83a443a0c 100644 --- a/lib/loopdev.c +++ b/lib/loopdev.c @@ -1076,6 +1076,46 @@ char *loopdev_find_by_backing_file(const char *filename, uint64_t offset, int fl return res; } +/* + * Returns number of loop devices associated with @file, if only one loop + * device is associeted with the given @filename and @loopdev is not NULL then + * @loopdev returns name of the device. + */ +int loopdev_count_by_backing_file(const char *filename, char **loopdev) +{ + struct loopdev_cxt lc; + int count = 0; + + if (!filename) + return -1; + + loopcxt_init(&lc, 0); + if (loopcxt_init_iterator(&lc, LOOPITER_FL_USED)) + return -1; + + while(loopcxt_next(&lc) == 0) { + char *backing = loopcxt_get_backing_file(&lc); + + if (!backing || strcmp(backing, filename)) { + free(backing); + continue; + } + + free(backing); + if (loopdev && count == 0) + *loopdev = loopcxt_strdup_device(&lc); + count++; + } + + loopcxt_deinit(&lc); + + if (loopdev && count > 1) { + free(*loopdev); + *loopdev = NULL; + } + return count; +} + #ifdef TEST_PROGRAM_LOOPDEV #include <errno.h> |