fs: fat: add rename
The implementation roughly follows the POSIX specification for rename() [1]. The ordering of operations attempting to minimize the chance for data loss in unexpected circumstances. The 'mv' command was implemented as a front end for the rename operation as that is what most users are likely familiar with in terms of behavior. The 'FAT_RENAME' Kconfig option was added to prevent code size increase on size-oriented builds like SPL. [1] https://pubs.opengroup.org/onlinepubs/9799919799/functions/rename.html Signed-off-by: Gabriel Dalimonte <gabriel.dalimonte@gmail.com>
This commit is contained in:
Gabriel Dalimonte
committed by
Tom Rini
Tom Rini
parent
d9c149664f
commit
06159a1465
@@ -13,6 +13,13 @@ config FAT_WRITE
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This provides support for creating and writing new files to an
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existing FAT filesystem partition.
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config FAT_RENAME
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bool "Enable filesystem rename support"
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depends on FAT_WRITE
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help
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This provides support for renaming and moving files within a
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FAT filesystem partition.
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config FS_FAT_MAX_CLUSTSIZE
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int "Set maximum possible clustersize"
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default 65536
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@@ -1215,6 +1215,28 @@ static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
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memcpy(&dentptr->nameext, shortname, SHORT_NAME_SIZE);
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}
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/**
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* fat_itr_parent() - modifies the iterator to the parent directory of the
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* current iterator.
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*
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* @itr: iterator positioned anywhere in a directory
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* @Return: 0 if the iterator is in the parent directory, -errno otherwise
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*/
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static int fat_itr_parent(fat_itr *itr)
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{
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int ret;
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if (itr->is_root)
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return -EIO;
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/* ensure iterator is at the first directory entry */
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ret = fat_move_to_cluster(itr, itr->start_clust);
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if (ret)
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return ret;
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return fat_itr_resolve(itr, "..", TYPE_DIR);
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}
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/**
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* create_link() - inserts a directory entry for a file or directory
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*
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@@ -1822,3 +1844,266 @@ exit:
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free(dotdent);
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return ret;
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}
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/**
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* check_path_prefix() - ensures one path does not contains another path as a
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* prefix.
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*
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* for example: path foo/bar/baz/qux contains the path prefix foo/bar/baz
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*
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* note: the iterator may be pointing to any directory entry in the directory
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*
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* @prefix_clust: start cluster of the final directory in the prefix path
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* (the start cluster of 'baz' in the above example)
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* @path_itr: iterator of the path to check (an iterator pointing to any
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* direntry in 'qux' in the above example)
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* Return: -errno on error, 0 if path_itr does not have the directory
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* at prefix_clust as an ancestor.
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*/
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static int check_path_prefix(loff_t prefix_clust, fat_itr *path_itr)
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{
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fat_itr itr;
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fsdata fsdata = { .fatbuf = NULL, }, *mydata = &fsdata;
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int ret;
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/* duplicate fsdata */
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itr = *path_itr;
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fsdata = *itr.fsdata;
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/* allocate local fat buffer */
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fsdata.fatbuf = malloc_cache_aligned(FATBUFSIZE);
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if (!fsdata.fatbuf) {
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log_debug("Error: allocating memory\n");
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ret = -ENOMEM;
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goto exit;
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}
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fsdata.fatbufnum = -1;
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itr.fsdata = &fsdata;
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/* ensure iterator is at the first directory entry */
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ret = fat_move_to_cluster(&itr, itr.start_clust);
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if (ret)
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goto exit;
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while (1) {
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if (prefix_clust == itr.start_clust) {
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ret = -EINVAL;
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goto exit;
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}
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if (itr.is_root) {
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ret = 0;
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goto exit;
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}
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/* Should not occur in a well-formed FAT filesystem besides the root */
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if (fat_itr_parent(&itr)) {
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log_debug("FAT filesystem corrupt!\n");
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log_debug("dir @ clust %u has no parent direntry\n",
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itr.start_clust);
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ret = -EIO;
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goto exit;
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}
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}
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exit:
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free(fsdata.fatbuf);
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return ret;
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}
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/**
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* fat_rename - rename/move a file or directory
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*
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* @old_path: path to the existing file/directory
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* @new_path: new path/name for the rename/move
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* Return: 0 on success, -errno otherwise
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*/
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int fat_rename(const char *old_path, const char *new_path)
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{
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fat_itr *old_itr = NULL, *new_itr = NULL;
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fsdata old_datablock = { .fatbuf = NULL, };
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fsdata new_datablock = { .fatbuf = NULL, };
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/* used for START macro */
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fsdata *mydata = &old_datablock;
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int ret = -EIO, is_old_dir;
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char *old_path_copy, *old_dirname, *old_basename;
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char *new_path_copy, *new_dirname, *new_basename;
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char l_new_basename[VFAT_MAXLEN_BYTES];
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__u32 old_clust;
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dir_entry *found_existing;
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/* only set if found_existing != NULL */
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__u32 new_clust;
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old_path_copy = strdup(old_path);
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new_path_copy = strdup(new_path);
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old_itr = malloc_cache_aligned(sizeof(fat_itr));
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new_itr = malloc_cache_aligned(sizeof(fat_itr));
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if (!old_path_copy || !new_path_copy || !old_itr || !new_itr) {
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log_debug("Error: out of memory\n");
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ret = -ENOMEM;
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goto exit;
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}
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split_filename(old_path_copy, &old_dirname, &old_basename);
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split_filename(new_path_copy, &new_dirname, &new_basename);
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if (normalize_longname(l_new_basename, new_basename)) {
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log_debug("FAT: illegal filename (%s)\n", new_basename);
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ret = -EINVAL;
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goto exit;
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}
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if (!strcmp(old_basename, ".") || !strcmp(old_basename, "..") ||
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!strcmp(old_basename, "") || !strcmp(l_new_basename, ".") ||
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!strcmp(l_new_basename, "..") || !strcmp(l_new_basename, "")) {
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ret = -EINVAL;
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goto exit;
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}
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/* checking for old_path == new_path is deferred until they're resolved */
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/* resolve old_path */
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ret = fat_itr_root(old_itr, &old_datablock);
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if (ret)
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goto exit;
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ret = fat_itr_resolve(old_itr, old_dirname, TYPE_DIR);
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if (ret) {
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log_debug("%s doesn't exist (%d)\n", old_dirname, ret);
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ret = -ENOENT;
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goto exit;
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}
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if (!find_directory_entry(old_itr, old_basename)) {
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log_debug("%s doesn't exist (%d)\n", old_basename, -ENOENT);
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ret = -ENOENT;
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goto exit;
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}
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/* store clust old_path points to, to relink later */
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total_sector = old_datablock.total_sect;
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old_clust = START(old_itr->dent);
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is_old_dir = fat_itr_isdir(old_itr);
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/* resolve new_path*/
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ret = fat_itr_root(new_itr, &new_datablock);
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if (ret)
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goto exit;
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ret = fat_itr_resolve(new_itr, new_dirname, TYPE_DIR);
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if (ret) {
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log_debug("%s doesn't exist (%d)\n", new_dirname, ret);
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ret = -ENOENT;
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goto exit;
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}
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found_existing = find_directory_entry(new_itr, l_new_basename);
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if (found_existing) {
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/* store cluster of new_path since it may need to be deleted */
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new_clust = START(new_itr->dent);
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/* old_path is new_path, noop */
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if (old_clust == new_clust) {
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ret = 0;
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goto exit;
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}
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if (fat_itr_isdir(new_itr) != is_old_dir) {
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if (is_old_dir)
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ret = -ENOTDIR;
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else
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ret = -EISDIR;
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goto exit;
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}
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}
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if (is_old_dir) {
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ret = check_path_prefix(old_clust, new_itr);
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if (ret)
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goto exit;
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}
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/* create/update dentry to point to old_path's data cluster */
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if (found_existing) {
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struct nameext new_name = new_itr->dent->nameext;
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__u8 lcase = new_itr->dent->lcase;
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if (is_old_dir) {
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int n_entries = fat_dir_entries(new_itr);
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if (n_entries < 0) {
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ret = n_entries;
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goto exit;
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}
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if (n_entries > 2) {
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log_debug("Error: directory is not empty: %d\n",
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n_entries);
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ret = -ENOTEMPTY;
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goto exit;
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}
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}
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*new_itr->dent = *old_itr->dent;
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new_itr->dent->nameext = new_name;
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new_itr->dent->lcase = lcase;
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} else {
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/* reset iterator to the start of the directory */
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ret = fat_move_to_cluster(new_itr, new_itr->start_clust);
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if (ret)
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goto exit;
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ret = create_link(new_itr, l_new_basename, old_clust,
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old_itr->dent->size,
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old_itr->dent->attr | ATTR_ARCH);
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if (ret)
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goto exit;
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}
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ret = flush_dir(new_itr);
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if (ret)
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goto exit;
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/* with new_path data cluster unreferenced, clear it */
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if (found_existing) {
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ret = clear_fatent(&new_datablock, new_clust);
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if (ret)
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goto exit;
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}
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/* update moved directory so the parent is new_path */
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if (is_old_dir) {
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__u32 clust = new_itr->start_clust;
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dir_entry *dent;
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fat_itr_child(new_itr, new_itr);
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dent = find_directory_entry(new_itr, "..");
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if (!dent) {
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log_debug("FAT filesystem corrupt!\n");
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log_debug("dir %s has no parent direntry\n",
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l_new_basename);
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ret = -EIO;
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goto exit;
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}
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set_start_cluster(&new_datablock, dent, clust);
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ret = flush_dir(new_itr);
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if (ret)
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goto exit;
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}
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/* refresh old in case write happened to the same block. */
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ret = fat_move_to_cluster(old_itr, old_itr->dent_clust);
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if (ret)
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goto exit;
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ret = delete_dentry_link(old_itr);
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exit:
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free(new_datablock.fatbuf);
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free(old_datablock.fatbuf);
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free(new_itr);
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free(old_itr);
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free(new_path_copy);
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free(old_path_copy);
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return ret;
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}
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65
fs/fs.c
65
fs/fs.c
@@ -213,12 +213,16 @@ static struct fstype_info fstypes[] = {
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.unlink = fs_unlink_unsupported,
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.mkdir = fs_mkdir_unsupported,
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#endif
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.rename = fs_rename_unsupported,
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.uuid = fat_uuid,
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.opendir = fat_opendir,
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.readdir = fat_readdir,
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.closedir = fat_closedir,
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.ln = fs_ln_unsupported,
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#if CONFIG_IS_ENABLED(FAT_RENAME) && !IS_ENABLED(CONFIG_XPL_BUILD)
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.rename = fat_rename,
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#else
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.rename = fs_rename_unsupported,
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#endif
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},
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#endif
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@@ -1007,6 +1011,65 @@ int do_ln(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[],
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return 0;
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}
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int do_mv(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[],
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int fstype)
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{
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struct fs_dir_stream *dirs;
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char *src = argv[3];
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char *dst = argv[4];
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char *new_dst = NULL;
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int ret = 1;
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if (argc != 5) {
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ret = CMD_RET_USAGE;
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goto exit;
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}
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if (fs_set_blk_dev(argv[1], argv[2], fstype))
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goto exit;
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dirs = fs_opendir(dst);
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/* dirs being valid means dst points to an existing directory.
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* mv should copy the file/dir (keeping the same name) into the
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* directory
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*/
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if (dirs) {
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char *src_name = strrchr(src, '/');
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int dst_len;
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if (src_name)
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src_name += 1;
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else
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src_name = src;
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dst_len = strlen(dst);
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new_dst = calloc(1, dst_len + strlen(src_name) + 2);
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strcpy(new_dst, dst);
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/* If there is already a trailing slash, don't add another */
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if (new_dst[dst_len - 1] != '/') {
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new_dst[dst_len] = '/';
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dst_len += 1;
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}
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strcpy(new_dst + dst_len, src_name);
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dst = new_dst;
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}
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fs_closedir(dirs);
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if (fs_set_blk_dev(argv[1], argv[2], fstype))
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goto exit;
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if (fs_rename(src, dst))
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goto exit;
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ret = 0;
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exit:
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free(new_dst);
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return ret;
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}
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int do_fs_types(struct cmd_tbl *cmdtp, int flag, int argc, char * const argv[])
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{
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struct fstype_info *drv = fstypes;
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