fs: add unlink interface

"unlink" interface is added to file operations.
This is a preparatory change as unlink support for FAT file system
will be added in next patch.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

fs/fs.c

@@ -105,6 +105,11 @@ static inline int fs_opendir_unsupported(const char *filename,
 	return -EACCES;
 }
 
+static inline int fs_unlink_unsupported(const char *filename)
+{
+	return -1;
+}
+
 static inline int fs_mkdir_unsupported(const char *dirname)
 {
 	return -1;
@@ -147,6 +152,7 @@ struct fstype_info {
 	int (*readdir)(struct fs_dir_stream *dirs, struct fs_dirent **dentp);
 	/* see fs_closedir() */
 	void (*closedir)(struct fs_dir_stream *dirs);
+	int (*unlink)(const char *filename);
 	int (*mkdir)(const char *dirname);
 };
 
@@ -173,6 +179,7 @@ static struct fstype_info fstypes[] = {
 		.opendir = fat_opendir,
 		.readdir = fat_readdir,
 		.closedir = fat_closedir,
+		.unlink = fs_unlink_unsupported,
 	},
 #endif
 #ifdef CONFIG_FS_EXT4
@@ -193,6 +200,7 @@ static struct fstype_info fstypes[] = {
 #endif
 		.uuid = ext4fs_uuid,
 		.opendir = fs_opendir_unsupported,
+		.unlink = fs_unlink_unsupported,
 		.mkdir = fs_mkdir_unsupported,
 	},
 #endif
@@ -210,6 +218,7 @@ static struct fstype_info fstypes[] = {
 		.write = fs_write_sandbox,
 		.uuid = fs_uuid_unsupported,
 		.opendir = fs_opendir_unsupported,
+		.unlink = fs_unlink_unsupported,
 		.mkdir = fs_mkdir_unsupported,
 	},
 #endif
@@ -227,6 +236,7 @@ static struct fstype_info fstypes[] = {
 		.write = fs_write_unsupported,
 		.uuid = fs_uuid_unsupported,
 		.opendir = fs_opendir_unsupported,
+		.unlink = fs_unlink_unsupported,
 		.mkdir = fs_mkdir_unsupported,
 	},
 #endif
@@ -244,6 +254,7 @@ static struct fstype_info fstypes[] = {
 		.write = fs_write_unsupported,
 		.uuid = btrfs_uuid,
 		.opendir = fs_opendir_unsupported,
+		.unlink = fs_unlink_unsupported,
 		.mkdir = fs_mkdir_unsupported,
 	},
 #endif
@@ -260,6 +271,7 @@ static struct fstype_info fstypes[] = {
 		.write = fs_write_unsupported,
 		.uuid = fs_uuid_unsupported,
 		.opendir = fs_opendir_unsupported,
+		.unlink = fs_unlink_unsupported,
 		.mkdir = fs_mkdir_unsupported,
 	},
 };
@@ -510,6 +522,19 @@ void fs_closedir(struct fs_dir_stream *dirs)
 	fs_close();
 }
 
+int fs_unlink(const char *filename)
+{
+	int ret;
+
+	struct fstype_info *info = fs_get_info(fs_type);
+
+	ret = info->unlink(filename);
+
+	fs_type = FS_TYPE_ANY;
+	fs_close();
+
+	return ret;
+}
 
 int fs_mkdir(const char *dirname)
 {
@@ -727,6 +752,21 @@ int do_fs_type(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 	return CMD_RET_SUCCESS;
 }
 
+int do_rm(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
+	  int fstype)
+{
+	if (argc != 4)
+		return CMD_RET_USAGE;
+
+	if (fs_set_blk_dev(argv[1], argv[2], fstype))
+		return 1;
+
+	if (fs_unlink(argv[3]))
+		return 1;
+
+	return 0;
+}
+
 int do_mkdir(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
 	     int fstype)
 {

include/fs.h

@@ -155,6 +155,16 @@ struct fs_dirent *fs_readdir(struct fs_dir_stream *dirs);
  */
 void fs_closedir(struct fs_dir_stream *dirs);
 
+/*
+ * fs_unlink - delete a file or directory
+ *
+ * If a given name is a directory, it will be deleted only if it's empty
+ *
+ * @filename: Name of file or directory to delete
+ * @return 0 on success, -1 on error conditions
+ */
+int fs_unlink(const char *filename);
+
 /*
  * fs_mkdir - Create a directory
  *
@@ -177,6 +187,8 @@ int file_exists(const char *dev_type, const char *dev_part, const char *file,
 		int fstype);
 int do_save(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
 		int fstype);
+int do_rm(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
+		int fstype);
 int do_mkdir(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
 		int fstype);