fs.h

#ifndef FS_H
#define FS_H

#include <std/common.h>

#define FS_FILE     0x01
#define FS_DIRECTORY    0x02
#define FS_CHARDEVICE   0x03
#define FS_BLOCKDEVICE  0x04
#define FS_PIPE     0x05
#define FS_SYMLINK  0x06
#define FS_MOUNTPOINT   0x08 //use 8 instead of 7 so we can OR with FS_DIRECTORY

#define EOF (-1)

enum {
    SEEK_SET = 0,
    SEEK_CUR,
    SEEK_END,
};

struct fs_node;

typedef uint32_t (*read_type_t)(struct fs_node*, uint32_t, uint32_t, uint8_t*);
typedef uint32_t (*write_type_t)(struct fs_node*, uint32_t, uint32_t, uint8_t*);
typedef void (*open_type_t)(struct fs_node*);
typedef void (*close_type_t)(struct fs_node*);
typedef struct dirent * (*readdir_type_t)(struct fs_node*, uint32_t);
typedef struct fs_node * (*finddir_type_t)(struct fs_node*, char* name);

typedef struct fs_node {
    char name[128];     //filename
    uint32_t mask;      //permission mask
    uint32_t uid;       //owning user
    uint32_t gid;       //owning group
    uint32_t flags;     //includes node type
    uint32_t inode;     //allows fs to identify files
    uint32_t length;    //size of file (bytes)
    uint32_t impl;      
    read_type_t read;
    write_type_t write;
    open_type_t open;
    close_type_t close;
    readdir_type_t readdir;
    finddir_type_t finddir;
    struct fs_node* ptr;    //used by mountpoints and symlinks
    struct fs_node* parent; //parent directory of this node
} fs_node_t;

typedef struct file_t {
    uint32_t fpos;
    fs_node_t* node;
} FILE;

struct dirent {
    char name[128];     //filename
    uint32_t ino;       //inode number
};

extern fs_node_t* fs_root; //filesystem root

//standard read/write/open/close
//note: these are suffixed with _fs to distinguish from the functions
//that deal with file descriptors, not file nodes
uint32_t read_fs(fs_node_t* node, uint32_t offset, uint32_t size, uint8_t* buffer);
uint32_t write_fs(fs_node_t* node, uint32_t offset, uint32_t size, uint8_t* buffer);
void open_fs(fs_node_t* node, uint8_t read, uint8_t write);
void close_fs(fs_node_t* node);
struct dirent* readdir_fs(fs_node_t* node, uint32_t index);
fs_node_t* finddir_fs(fs_node_t* node, char* name);

FILE* fopen(char* filename, char* mode);
void fclose(FILE* stream);

int ftell(FILE* stream);
int fseek(FILE* stream, long offset, int origin);
uint8_t fgetc(FILE* stream);

uint32_t fread(void* buffer, uint32_t size, uint32_t count, FILE* stream);
uint32_t read(int fd, void* buf, uint32_t count);

#endif