mufs: implement modes for read, write and append in mufs_open()

include/fs/mufs.h

@@ -26,6 +26,10 @@ struct mufs_dirent {
 	uint8_t type;
 };
 
+#define MUFS_READ   BIT(0)
+#define MUFS_WRITE  BIT(1)
+#define MUFS_APPEND BIT(2)
+
 int mufs_mount(struct mufs *fs, struct flash_dev *dev);
 int mufs_format(struct flash_dev *dev);
 
@@ -36,7 +40,7 @@ int mufs_readdir(struct mufs_dir *dir, struct mufs_dirent *dirent);
 int mufs_mkdir(struct mufs *fs, const char *path);
 
 int mufs_create(struct mufs *fs, const char *path);
-struct mufs_file *mufs_open(struct mufs *fs, const char *path);
+struct mufs_file *mufs_open(struct mufs *fs, const char *path, int mode);
 void mufs_close(struct mufs_file *file);
 size_t mufs_read(struct mufs_file *file, void *data, size_t len);
 size_t mufs_write(struct mufs_file *file, const void *data, size_t len);

source/fs/mufs/file.c

@@ -15,6 +15,7 @@
 struct mufs_file {
 	struct mufs *fs;
 	struct mufs_tree *tree;
+	int mode;
 	uint32_t va;
 };
 
@@ -23,7 +24,7 @@ int mufs_create(struct mufs *fs, const char *path)
 	return mufs_mkpath(fs, path, MUFS_FILE);
 }
 
-struct mufs_file *mufs_open(struct mufs *fs, const char *path)
+struct mufs_file *mufs_open(struct mufs *fs, const char *path, int mode)
 {
 	struct mufs_file *file;
 
@@ -35,6 +36,7 @@ struct mufs_file *mufs_open(struct mufs *fs, const char *path)
 	if (!(file->tree = resolve_path(fs, path)))
 		goto err_free_file;
 
+	file->mode = mode;
 	file->va = 0;
 
 	return file;
@@ -59,6 +61,9 @@ size_t mufs_read(struct mufs_file *file, void *data, size_t len)
 	if (!file || !data || !len)
 		return 0;
 
+	if (!(file->mode & MUFS_READ))
+		return 0;
+
 	if (!(ret = mufs_tree_read(file->tree, data, file->va, len)))
 		return 0;
 
@@ -74,6 +79,12 @@ size_t mufs_write(struct mufs_file *file, const void *data, size_t len)
 	if (!file || !data || !len)
 		return 0;
 
+	if (!(file->mode & MUFS_WRITE))
+		return 0;
+
+	if (file->mode & MUFS_APPEND)
+		file->va = file->tree->file_size;
+
 	if (!(ret = mufs_tree_write(file->tree, (void *)data, file->va, len)))
 		return 0;