Aren/rulimine
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

got directory reading and more specifically root directory reading

Browse Source
This commit is contained in:
Itay Almog 2021-09-28 22:07:43 +03:00
parent 66564de7e0
commit 3f37d82cdd
2 changed files with 152 additions and 47 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
stage23/fs/ntfs.h
View File

@ -33,16 +33,22 @@ struct ntfs_file_handle {
struct volume *part;
struct ntfs_bpb bpb;
uint8_t mft_run_list[256];
uint8_t root_run_list[128];
uint8_t resident_index[256];
uint8_t attribute_list[256];
uint64_t mft_offset;
// file record sizes
uint64_t file_record_size;
uint64_t sectors_per_file_record;
// MFT info, the offset and its runlist
uint64_t mft_offset;
uint8_t mft_run_list[256];
// the runlist, resident index and attribute list of the
// current open file/directory
uint8_t run_list[128];
uint8_t resident_index[256];
uint8_t attribute_list[256];
// info about the current file
uint32_t size_bytes;
};

181
stage23/fs/ntfs.s2.c
View File

@ -1,5 +1,5 @@
#include <fs/ntfs.h>
#include <mm/pmm.h>
#include <lib/print.h>
#include <stdbool.h>
@ -102,6 +102,45 @@ int ntfs_check_signature(struct volume *part) {
return 1;
}
// the temp buffer is used for storing dirs and alike
// in memory, because limine only has allocate without
// free we are going to allocate it once globally and just
// make sure to only use it in the ntfs_open function...
static uint8_t *temp_buffer = NULL;
static size_t temp_buffer_size = 0;
/**
* Get an attribute from the given file record
*/
static bool ntfs_get_file_record_attr(uint8_t* file_record, uint32_t attr_type, uint8_t **out_attr) {
struct mft_file_record *fr = (struct mft_file_record *)file_record;
// get the offset to the first attribute
uint8_t *cur_attr_ptr = file_record + fr->attribute_offset;
while (true) {
// TODO: don't check for the min size, but for the actual size...
if (cur_attr_ptr + sizeof(struct file_record_attr_header) > file_record + MIN_FILE_RECORD_SIZE)
panic("NTFS: File record attribute is outside of file record");
struct file_record_attr_header *cur_attr = (struct file_record_attr_header *)cur_attr_ptr;
if (cur_attr->type == attr_type) {
*out_attr = cur_attr_ptr;
return true;
}
// we either found an attr with higher type or the end type
if (cur_attr->type > attr_type || cur_attr->type == 0xFF)
return false;
if (cur_attr->length == 0)
panic("NTFS: File record attribute has zero length");
cur_attr_ptr += cur_attr->length;
}
}
/**
* Gets a count and cluster from the runlist, if next is true then it updates the list intenrally
* so the next call will return the next element
@ -201,7 +240,7 @@ static bool ntfs_get_file_record(struct ntfs_file_handle *handle, uint64_t mft_r
panic("NTFS: Failed to read file record from mft");
// make sure this is a valid file record
struct mft_file_record* fr = (struct mft_file_record*)file_record_buffer;
struct mft_file_record *fr = (struct mft_file_record *)file_record_buffer;
if (strncmp(fr->name, "FILE", SIZEOF_ARRAY(fr->name)))
panic("NTFS: File record has invalid signature (got %c%c%c%c, should be FILE)!",
fr->name[0], fr->name[1], fr->name[2], fr->name[3]);
@ -213,44 +252,57 @@ static bool ntfs_get_file_record(struct ntfs_file_handle *handle, uint64_t mft_r
/**
* Read the the directory's file record from the mft
*/
static bool ntfs_read_directory(struct ntfs_file_handle *handle, uint64_t mft_record, uint8_t *file_record) {
static int ntfs_read_directory(struct ntfs_file_handle *handle, uint64_t mft_record, uint8_t *file_record) {
// get the record of the directory
if (!ntfs_get_file_record(handle, mft_record, file_record))
return false;
return 0;
return true;
}
//
// get the runlist of the directory
//
/**
* Get an attribute from the given file record
*/
static bool ntfs_get_file_record_attr(uint8_t* file_record, uint32_t attr_type, uint8_t **out_attr) {
struct mft_file_record *fr = (struct mft_file_record *)file_record;
// get the index alloc attribute, it should have the runlist offset
// copy the runlist from it to our handle for easier access
uint8_t *index_alloc_ptr;
if (!ntfs_get_file_record_attr(file_record, FR_ATTRIBUTE_INDEX_ALLOC, &index_alloc_ptr))
panic("NTFS: Directory has no runlist?!");
struct file_record_attr_header_non_res *index_alloc = (struct file_record_attr_header_non_res *)index_alloc_ptr;
uint8_t *runlist_ptr = index_alloc_ptr + index_alloc->run_offset;
if (runlist_ptr - file_record + 128u > handle->file_record_size)
panic("NTFS: runlist is outside of file record!");
memcpy(handle->run_list, runlist_ptr, sizeof(handle->run_list));
// get the offset to the first attribute
uint8_t* cur_attr_ptr = file_record + fr->attribute_offset;
// calculate the directory size by just going through the runlist
uint8_t *runlist = handle->run_list;
uint64_t dir_size = 0;
uint64_t cluster = 0;
uint64_t cluster_count = 0;
bool status = false;
do {
status = ntfs_get_next_run_list_element(&runlist, &cluster_count, &cluster, true);
if (status)
dir_size += cluster_count;
} while(status);
dir_size *= handle->bpb.sectors_per_cluster * handle->bpb.bytes_per_sector;
while (true) {
// TODO: don't check for the min size, but for the actual size...
if (cur_attr_ptr + sizeof(struct file_record_attr_header) > file_record + MIN_FILE_RECORD_SIZE)
panic("NTFS: File record attribute is outside of file record");
struct file_record_attr_header *cur_attr = (struct file_record_attr_header *)cur_attr_ptr;
if (cur_attr->type == attr_type) {
*out_attr = cur_attr_ptr;
return true;
// allocate a buffer for the directory data
if (temp_buffer == NULL) {
// allocate enough just in case, idk how much is good
temp_buffer_size = dir_size > 64 * 1024 ? dir_size : 64 * 1024;
temp_buffer = ext_mem_alloc(temp_buffer_size);
} else {
// we must truncate it...
if (dir_size > temp_buffer_size) {
dir_size = temp_buffer_size;
}
// we either found an attr with higher type or the end type
if (cur_attr->type > attr_type || cur_attr->type == 0xFF)
return false;
if (cur_attr->length == 0)
panic("NTFS: File record attribute has zero length");
cur_attr_ptr += cur_attr->length;
}
// read the directory
if (ntfs_read(handle, temp_buffer, 0, dir_size) != (int)dir_size)
panic("NTFS: EOF before reading directory fully...");
// return the size of the directory
return dir_size;
}
/**
@ -261,14 +313,15 @@ static void ntfs_read_root(struct ntfs_file_handle *handle) {
handle->mft_offset = (uint64_t)handle->bpb.mft_cluster * (uint64_t)handle->bpb.sectors_per_cluster * (uint64_t)handle->bpb.bytes_per_sector;
// read the mft file record, this should be the size of a sector
uint8_t file_record_buffer[handle->file_record_size];
uint8_t file_record_buffer[MIN_FILE_RECORD_SIZE];
if (!volume_read(handle->part, file_record_buffer, handle->mft_offset, sizeof(file_record_buffer)))
panic("NTFS: Failed to read MFT file record");
// get the file attribute
struct file_record_attr_header_non_res *attr;
if (!ntfs_get_file_record_attr(file_record_buffer, FR_ATTRIBUTE_DATA, (uint8_t **)&attr))
uint8_t *attr_ptr = NULL;
if (!ntfs_get_file_record_attr(file_record_buffer, FR_ATTRIBUTE_DATA, &attr_ptr))
panic("NTFS: MFT file record missing DATA attribute");
struct file_record_attr_header_non_res *attr = (struct file_record_attr_header_non_res *)attr_ptr;
// verify the attr and run list are in the buffer
if ((uint8_t *)attr + sizeof(*attr) > file_record_buffer + sizeof(file_record_buffer))
@ -304,7 +357,7 @@ int ntfs_open(struct ntfs_file_handle *ret, struct volume *part, const char *pat
ret->sectors_per_file_record = 1;
ret->file_record_size = ret->bpb.bytes_per_sector;
}
// now prepare the root directory so we can search for
// the rest of the stuff
ntfs_read_root(ret);
@ -316,9 +369,55 @@ int ntfs_open(struct ntfs_file_handle *ret, struct volume *part, const char *pat
}
int ntfs_read(struct ntfs_file_handle *file, void *buf, uint64_t loc, uint64_t count) {
(void)file;
(void)buf;
(void)loc;
(void)count;
return 1;
// get the runlist
uint8_t *runlist = file->run_list;
// we are going to go over the runlist until we get to the offset
// once we get to the offset we are going to continue going over
// the runlist while copying bytes
uint64_t wanted_to_read = count;
uint64_t bytes_per_cluster = file->bpb.sectors_per_cluster * file->bpb.bytes_per_sector;
do {
// get the next element from the runlist
uint64_t cluster_count;
uint64_t cluster;
if (!ntfs_get_next_run_list_element(&runlist, &cluster_count, &cluster, true))
break;
// calculate the cont size and offset on disk
uint64_t total_cont_bytes = cluster_count * bytes_per_cluster;
uint64_t abs_byte = cluster * bytes_per_cluster;
// check if we arrived at the wanted offset
if (loc != 0) {
if (loc >= total_cont_bytes) {
// we need to go more...
loc -= total_cont_bytes;
} else {
// we got to the offset, adjust base and size
// and set the loc to 0
total_cont_bytes -= loc;
abs_byte += loc;
loc = 0;
}
}
if (loc == 0) {
// get how much we wanna read now and
// subtract that from the total we need
// to read
size_t read_now = total_cont_bytes;
if (read_now > count) {
read_now = count;
}
count -= read_now;
// read it!
if (!volume_read(file->part, buf, abs_byte, read_now))
panic("NTFS: Runlist points to outside the volume (%x)", abs_byte);
}
} while(count);
// return how much we read...
return wanted_to_read - count;
}