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KimisOS
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KimisOS/src/kernel/system/vfs.c

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#include "vfs.h"
#include "../shared/kstdlib.h"
#include "../shared/memory.h"
#include "../shared/string.h"
#define MODULE_NAME "KVFS"
vfile_t root_dir = {"/", VFILE_DIRECTORY};
struct mount_handler{
int (*callback)(vfile_t *device, MOUNT_OPERATION op, ...);
uint32_t key;
}mount_handlers[32];
void vfs_add_mount_handler(int (*mount_handler)(vfile_t *device, MOUNT_OPERATION op, ...), uint32_t key){
if(mount_handler == 0){
return;
}
for(uint32_t i = 0; i < 32; i++){
if(mount_handlers[i].callback == 0){
mount_handlers[i].callback = mount_handler;
mount_handlers[i].key = key;
}
}
}
void vfs_del_mount_handler(uint32_t key){
for(uint32_t i = 0; i < 32; i++){
if(mount_handlers[i].key == key){
mount_handlers[i].callback = 0;
mount_handlers[i].key = 0;
}
}
}
void vfs_init(){
mlog(MODULE_NAME, "Initializing VFS\n", MLOG_PRINT);
root_dir.access.data.ptr = kmalloc(1);
root_dir.access.data.size_pgs = 1;
}
void add_file(vfile_t *vfile, vfile_t *current_dir){
vfile_t **dir_data = current_dir->access.data.ptr;
int i = 0;
while(dir_data[i] && (i * sizeof(vfile_t *))/4096 < current_dir->access.data.size_pgs){
i++;
}
dir_data[i] = vfile;
dir_data[i + 1] = 0;
}
/*
Long comment cause this one's a complicated one.
Create a file of the specified path in name
if the path leads to a mounted filesystem then
use the mounted filesystem's specified create() function to create the file.
else, create a pointer in the virtual path that points to a file entry for the new file.
If this new file is a Directory or Pointer, specify a pointer to be used as a buffer to store data for this file, as well as the size of the buffer, in pages.
If this new file is a Mounted filesystem, this pointer must be an array of functions as defined below:
int fwrite(vfile_t *file, void *data, uint32_t offset, uint32_t count);
//must write count bytes from data to file offset by offset bytes.
int fread(vfile_t *file, void *data, uint32_t offset, uint32_t count);
//must read count bytes from data to file offset by offset bytes.
int fopen(char *filename, vfile_t *file);
//must return a vfile_t struct written to the address specified in file, to represent a file named name (from the mount's filename)
(eg. /mount/root/test is passed as /root/test)
fcreate(char *filename, FS_FILE_FLAGS flags);
FS_FILE_FLAGS is in the same format as FAT's file attribute byte of dirents.
filenames are truncated, as with the previous example.
fdelete(vfile_t *file);
//the file specified in the file pointer must be deleted.
else, if the file is a virtual representation of a device, of of a file (any miscellaneous file object that does not fit the other types) then
specify a pointer to be used as the read function, as defined below:
void read(struct virtual_file *file, void *data, uint32_t offset, uint32_t count);
specify a pointer to be used as the write function, with the same function prototype as the function above
void write(struct virtual_file *file, void *data, uint32_t offset, uint32_t count);
*/
vfile_t *fcreate(char *name, VFILE_TYPE type, ...){
name += name[0]== '/';
char *last = strtok(name, '/');
char *tmp = last;
uint32_t filename_offset = 0;
vfile_t *current_dir = &root_dir;
vfile_t *tmpfile;
va_list args;
va_start(args, type);
while(tmp != 0){
// dir = tmp;
tmpfile = search_dir(tmp, *current_dir);
// printf("%s\n", name + filename_offset);
if(!tmpfile){
//create file in folder;
vfile_t *vfile = kmalloc(1);
vfile->type = type;
vfile->parent = current_dir;
uint32_t tmpnsize = strlen(tmp);
if(tmp[tmpnsize - 1] == '/'){
tmp[tmpnsize - 1] = 0;
}
strcpy(tmp, vfile->name);
switch(type){
case VFILE_POINTER:
case VFILE_DIRECTORY:
case VFILE_MOUNT:
case VFILE_SYMLINK:
void *ptr = va_arg(args, void*);
vfile->access.data.ptr = ptr;
vfile->access.data.size_pgs = va_arg(args, uint32_t);
// *(uint32_t *)(ptr + (vfile->access.data.size_pgs * 4096)) = 0;
// what was the above line even for
add_file(vfile, current_dir);
break;
case VFILE_FILE:
case VFILE_DEVICE:
void *write = va_arg(args, void *);
void *read = va_arg(args, void *);
vfile->access.funcs.write = write;
vfile->access.funcs.read = read;
// strcpy
add_file(vfile, current_dir);
break;
}
return vfile; //allow drivers to make last minute changes before it's sent to the user
}
if(tmpfile->type == VFILE_SYMLINK){
tmpfile = (vfile_t *)tmpfile->access.data.ptr;
}
switch(tmpfile->type){
case VFILE_DIRECTORY:
current_dir = tmpfile;
break;
case VFILE_MOUNT:
((mount_t*)(tmpfile->access.data.ptr))->create(name + filename_offset, type == VFILE_DIRECTORY ? FS_FILE_IS_DIR : 0);
return (void *)-1;
default:
// mlog(MODULE_NAME, "Error: Cannot create file with same name as another file! %d\n", MLOG_ERR, tmpfile->type);
return 0;
break;
}
filename_offset += strlen(tmp) + 1;
tmp = strtok(0, '/');
}
return 0;
}
//who needs a way to delete things?
//TODO: Write a function to delete files
void fdelete();
// navya was here https://github.com/novabansal
int fwrite(vfile_t *file_entry, void *byte_array, uint32_t offset, uint32_t count){
//sorry navya, I deleted the comment and it's not coming back :(
switch(file_entry->type){
case VFILE_DIRECTORY:
case VFILE_POINTER:
memcpy(byte_array, file_entry->access.data.ptr + offset, count);
return 0; //always successful. If it's not, there's been a page fault. Yk, quantum sort style.
break;
case VFILE_MOUNT:
mount_t *funcs = file_entry->access.data.ptr;
return funcs->write(file_entry, byte_array, offset, count);
case VFILE_PDIR:
case VFILE_FILE:
case VFILE_DEVICE:
return file_entry->access.funcs.write(file_entry, byte_array, offset, count);
break;
case VFILE_SYMLINK:
return fwrite(file_entry->access.data.ptr, byte_array, offset, count);
}
return INT32_MIN;//how did we get here?
}
int fread(vfile_t *file_entry, void *byte_array, uint32_t offset, uint32_t count){
switch(file_entry->type){
case VFILE_DIRECTORY:
case VFILE_POINTER:
memcpy(file_entry->access.data.ptr + offset, byte_array, count);
return 0; //always successful. If it's not, there's been a page fault. Yk, quantum sort style.
break;
case VFILE_MOUNT:
mount_t *funcs = file_entry->access.data.ptr;
return funcs->read(file_entry, byte_array, offset, count);
case VFILE_PDIR:
case VFILE_FILE:
case VFILE_DEVICE:
return file_entry->access.funcs.read(file_entry, byte_array, offset, count);
break;
case VFILE_SYMLINK:
return fread(file_entry->access.data.ptr, byte_array, offset, count);
}
return INT32_MIN; //Okay, alright, funny joke guys but we really shouldn't be able to get here
}
vfile_t *search_dir(char *name, vfile_t dir){
vfile_t **dir_data = (vfile_t **)dir.access.data.ptr;
uint32_t i = 0;
while(dir_data[i]){
if(!strcmp(dir_data[i]->name, name)){
return dir_data[i];
}
i++;
}
return 0;
}
vfile_t *fopen(char *name){
if(name[0] == '/'){
if(strlen(name) == 1){
return &root_dir;
}
name++;
}
if(name[strlen(name) - 1] == '/'){
name[strlen(name) - 1] = 0;
}
// printf("%s\n", name);
char *dir = strtok(name, '/');
// printf("%s", name);
char *tmp = dir;
uint32_t filename_offset = 0;
vfile_t *current_dir = &root_dir;
vfile_t *tmpfile;
while(tmp != 0){
dir = tmp;
tmpfile = search_dir(tmp, *current_dir);
if(!tmpfile){
// printf("not found\n");
return 0;
}
if(tmpfile->type == VFILE_SYMLINK){
tmpfile = (vfile_t *)tmpfile->access.data.ptr;
}
switch(tmpfile->type){
case VFILE_DIRECTORY:
// printf("found directory in %s: %s\n", current_dir->name, tmpfile->name);
current_dir = tmpfile;
break;
case VFILE_MOUNT:
vfile_t *file = kmalloc(1);
((mount_t*)(tmpfile->access.data.ptr))->open(name + filename_offset, file);
return file;
default:
return tmpfile;
}
filename_offset += strlen(tmp) + 1;
tmp = strtok(0, '/');
}
return tmpfile;
}
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