include/kernel/vfs.h

#pragma once

#include "kint.h"

struct fs_vtable;

#define FS_MAX_NAME_LEN 128

struct fs_node
{
	/** length of file name */
	uint name_len;
	/** file name */
	char name[128];
	/** identifier */
	uint inode;
	/** type of node */
	uint flags;
	/** permissions */
	uint mask;
	/** group id */
	uint gid;
	/** user id */
	uint uid;
	/** size in bytes */
	size_t size;
	/** reserved for driver */
	union
	{
		uint dri_res_i;
		void *dri_res_p;
	};

	struct fs_vtable *vtable;

	/** used for mounts */
	struct fs_node *mount;
};

struct fs_dirent
{
	// EXT2 supports up to 256 byte file names, so we will do the same
	char name[256];
	uint name_len;
	uint inode;
};

typedef uint (*fs_read_t)(struct fs_node *node, size_t offset, size_t size, uchar *buffer);
typedef uint (*fs_write_t)(struct fs_node *node, size_t offset, size_t size, uchar *buffer);
typedef void (*fs_open_t)(struct fs_node *node);
typedef void (*fs_close_t)(struct fs_node *node);

typedef bool (*fs_readdir_t)(struct fs_node *node, uint index, struct fs_dirent *dirent);
typedef struct fs_node *(*fs_finddir_t)(struct fs_node *node, char *name, uint name_len);

struct fs_vtable
{
	fs_read_t read;
	fs_write_t write;
	fs_open_t open;
	fs_close_t close;
	fs_readdir_t readdir;
	fs_finddir_t finddir;
};

enum fs_flags
{
	FS_FILE = 1,
	FS_DIRECTORY,
	FS_CHARDEVICE,
	FS_BLOCKDEVICE,
	FS_PIPE,
	FS_SYMLINK,

	FS_MOUNT = 8, /* Can be or'd with others */
};

extern struct fs_node root, dev, initrd;

/* Not to be confused normal open, close, etc functions, these operate
 * on the VFS directly
 * read and write return the number of bytes written/read,  */

uint fs_read(struct fs_node *node, size_t offset, size_t size, uchar *buffer);
uint fs_write(struct fs_node *node, size_t offset, size_t size, uchar *buffer);
void fs_open(struct fs_node *node);
void fs_close(struct fs_node *node);

bool fs_readdir(struct fs_node *node, uint index, struct fs_dirent *out);
struct fs_node *fs_finddir(struct fs_node *node, char *name, uint name_len);

/* Returns the following error codes:
 * 0: success
 * 1: target is not a directory
 * 2: target is already a mount point
 * 3: source is not a directory */
uint fs_mount(struct fs_node *target, struct fs_node *source);

void init_vfs();