fs: add rename infrastructure

The selection for *rename as the name for the rename/move operation
derives from the POSIX specification where they name the function
rename/renameat. [1] This aligns with Linux where the syscalls for
renaming/moving also use the rename/renameat naming.

[1] https://pubs.opengroup.org/onlinepubs/9799919799/functions/rename.html

Signed-off-by: Gabriel Dalimonte <gabriel.dalimonte@gmail.com>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

fs/fs.c

@@ -143,6 +143,12 @@ static inline int fs_mkdir_unsupported(const char *dirname)
 	return -1;
 }
 
+static inline int fs_rename_unsupported(const char *old_path,
+					const char *new_path)
+{
+	return -1;
+}
+
 struct fstype_info {
 	int fstype;
 	char *name;
@@ -183,6 +189,7 @@ struct fstype_info {
 	int (*unlink)(const char *filename);
 	int (*mkdir)(const char *dirname);
 	int (*ln)(const char *filename, const char *target);
+	int (*rename)(const char *old_path, const char *new_path);
 };
 
 static struct fstype_info fstypes[] = {
@@ -206,6 +213,7 @@ static struct fstype_info fstypes[] = {
 		.unlink = fs_unlink_unsupported,
 		.mkdir = fs_mkdir_unsupported,
 #endif
+		.rename = fs_rename_unsupported,
 		.uuid = fat_uuid,
 		.opendir = fat_opendir,
 		.readdir = fat_readdir,
@@ -238,6 +246,7 @@ static struct fstype_info fstypes[] = {
 		.closedir = ext4fs_closedir,
 		.unlink = fs_unlink_unsupported,
 		.mkdir = fs_mkdir_unsupported,
+		.rename = fs_rename_unsupported,
 	},
 #endif
 #if IS_ENABLED(CONFIG_SANDBOX) && !IS_ENABLED(CONFIG_XPL_BUILD)
@@ -257,6 +266,7 @@ static struct fstype_info fstypes[] = {
 		.unlink = fs_unlink_unsupported,
 		.mkdir = fs_mkdir_unsupported,
 		.ln = fs_ln_unsupported,
+		.rename = fs_rename_unsupported,
 	},
 #endif
 #if CONFIG_IS_ENABLED(SEMIHOSTING)
@@ -276,6 +286,7 @@ static struct fstype_info fstypes[] = {
 		.unlink = fs_unlink_unsupported,
 		.mkdir = fs_mkdir_unsupported,
 		.ln = fs_ln_unsupported,
+		.rename = fs_rename_unsupported,
 	},
 #endif
 #ifndef CONFIG_XPL_BUILD
@@ -296,6 +307,7 @@ static struct fstype_info fstypes[] = {
 		.unlink = fs_unlink_unsupported,
 		.mkdir = fs_mkdir_unsupported,
 		.ln = fs_ln_unsupported,
+		.rename = fs_rename_unsupported,
 	},
 #endif
 #endif
@@ -317,6 +329,7 @@ static struct fstype_info fstypes[] = {
 		.unlink = fs_unlink_unsupported,
 		.mkdir = fs_mkdir_unsupported,
 		.ln = fs_ln_unsupported,
+		.rename = fs_rename_unsupported,
 	},
 #endif
 #endif
@@ -339,6 +352,7 @@ static struct fstype_info fstypes[] = {
 		.ln = fs_ln_unsupported,
 		.unlink = fs_unlink_unsupported,
 		.mkdir = fs_mkdir_unsupported,
+		.rename = fs_rename_unsupported,
 	},
 #endif
 #if IS_ENABLED(CONFIG_FS_EROFS)
@@ -360,6 +374,7 @@ static struct fstype_info fstypes[] = {
 		.ln = fs_ln_unsupported,
 		.unlink = fs_unlink_unsupported,
 		.mkdir = fs_mkdir_unsupported,
+		.rename = fs_rename_unsupported,
 	},
 #endif
 	{
@@ -378,6 +393,7 @@ static struct fstype_info fstypes[] = {
 		.unlink = fs_unlink_unsupported,
 		.mkdir = fs_mkdir_unsupported,
 		.ln = fs_ln_unsupported,
+		.rename = fs_rename_unsupported,
 	},
 };
 
@@ -713,6 +729,22 @@ int fs_ln(const char *fname, const char *target)
 	return ret;
 }
 
+int fs_rename(const char *old_path, const char *new_path)
+{
+	struct fstype_info *info = fs_get_info(fs_type);
+	int ret;
+
+	ret = info->rename(old_path, new_path);
+
+	if (ret < 0) {
+		log_debug("Unable to rename %s -> %s\n", old_path, new_path);
+		ret = -1;
+	}
+	fs_close();
+
+	return ret;
+}
+
 int do_size(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[],
 	    int fstype)
 {

include/fs.h

@@ -86,7 +86,7 @@ int fs_set_blk_dev_with_part(struct blk_desc *desc, int part);
  *
  * Many file functions implicitly call fs_close(), e.g. fs_closedir(),
  * fs_exist(), fs_ln(), fs_ls(), fs_mkdir(), fs_read(), fs_size(), fs_write(),
- * fs_unlink().
+ * fs_unlink(), fs_rename().
  */
 void fs_close(void);
 
@@ -270,6 +270,18 @@ int fs_unlink(const char *filename);
  */
 int fs_mkdir(const char *filename);
 
+/**
+ * fs_rename - rename/move a file or directory
+ *
+ * @old_path: existing path of the file/directory to rename
+ * @new_path: new path of the file/directory. If this points to an existing
+ * file or empty directory, the existing file/directory will be unlinked.
+ * If this points to a non-empty directory, the rename will fail.
+ *
+ * Return: 0 on success, -1 on error conditions
+ */
+int fs_rename(const char *old_path, const char *new_path);
+
 /*
  * Common implementation for various filesystem commands, optionally limited
  * to a specific filesystem type via the fstype parameter.