485 lines
15 KiB
C
485 lines
15 KiB
C
#include <stdint.h>
|
|
#include <stddef.h>
|
|
#include <stdbool.h>
|
|
#include <fs/ext2.h>
|
|
#include <drivers/disk.h>
|
|
#include <lib/libc.h>
|
|
#include <lib/blib.h>
|
|
#include <lib/print.h>
|
|
#include <mm/pmm.h>
|
|
|
|
/* Inode types */
|
|
#define S_IFIFO 0x1000
|
|
#define S_IFCHR 0x2000
|
|
#define S_IFDIR 0x4000
|
|
#define S_IFBLK 0x6000
|
|
#define S_IFREG 0x8000
|
|
#define S_IFLNK 0xa000
|
|
#define S_IFSOCK 0xc000
|
|
|
|
#define FMT_MASK 0xf000
|
|
|
|
/* EXT2 Filesystem States */
|
|
#define EXT2_FS_UNRECOVERABLE_ERRORS 3
|
|
|
|
/* Ext2 incompatible features */
|
|
#define EXT2_IF_COMPRESSION 0x01
|
|
#define EXT2_IF_EXTENTS 0x40
|
|
#define EXT2_IF_64BIT 0x80
|
|
#define EXT2_IF_INLINE_DATA 0x8000
|
|
#define EXT2_IF_ENCRYPT 0x10000
|
|
#define EXT2_FEATURE_INCOMPAT_META_BG 0x0010
|
|
|
|
/* Ext4 flags */
|
|
#define EXT4_EXTENTS_FLAG 0x80000
|
|
|
|
#define EXT2_S_MAGIC 0xEF53
|
|
|
|
/* EXT2 Block Group Descriptor */
|
|
struct ext2_bgd {
|
|
uint32_t bg_block_bitmap;
|
|
uint32_t bg_inode_bitmap;
|
|
uint32_t bg_inode_table;
|
|
|
|
uint16_t bg_free_blocks_count;
|
|
uint16_t bg_free_inodes_count;
|
|
uint16_t bg_dirs_count;
|
|
|
|
uint16_t reserved[7];
|
|
} __attribute__((packed));
|
|
|
|
struct ext4_bgd {
|
|
uint32_t bg_block_bitmap;
|
|
uint32_t bg_inode_bitmap;
|
|
uint32_t bg_inode_table;
|
|
|
|
uint16_t bg_free_blocks_count;
|
|
uint16_t bg_free_inodes_count;
|
|
uint16_t bg_dirs_count;
|
|
|
|
uint16_t pad;
|
|
uint32_t reserved[3];
|
|
uint32_t block_id_hi;
|
|
uint32_t inode_id_hi;
|
|
uint32_t inode_table_id_hi;
|
|
uint16_t free_blocks_hi;
|
|
uint16_t free_inodes_hi;
|
|
uint16_t used_dirs_hi;
|
|
uint16_t pad2;
|
|
uint32_t reserved2[3];
|
|
} __attribute__((packed));
|
|
|
|
/* EXT2 Inode Types */
|
|
#define EXT2_INO_DIRECTORY 0x4000
|
|
|
|
/* EXT2 Directory Entry */
|
|
struct ext2_dir_entry {
|
|
uint32_t inode;
|
|
uint16_t rec_len;
|
|
uint8_t name_len;
|
|
uint8_t type;
|
|
} __attribute__((packed));
|
|
|
|
struct ext4_extent_header {
|
|
uint16_t magic;
|
|
uint16_t entries;
|
|
uint16_t max;
|
|
uint16_t depth;
|
|
uint16_t generation;
|
|
} __attribute__((packed));
|
|
|
|
struct ext4_extent {
|
|
uint32_t block;
|
|
uint16_t len;
|
|
uint16_t start_hi;
|
|
uint32_t start;
|
|
} __attribute__((packed));
|
|
|
|
struct ext4_extent_idx {
|
|
uint32_t block;
|
|
uint32_t leaf;
|
|
uint16_t leaf_hi;
|
|
uint16_t empty;
|
|
} __attribute__((packed));
|
|
|
|
static int inode_read(void *buf, uint64_t loc, uint64_t count,
|
|
struct ext2_inode *inode, struct ext2_file_handle *fd,
|
|
uint32_t *alloc_map);
|
|
static bool ext2_parse_dirent(struct ext2_dir_entry *dir, struct ext2_file_handle *fd, const char *path);
|
|
|
|
// parse an inode given the partition base and inode number
|
|
static bool ext2_get_inode(struct ext2_inode *ret,
|
|
struct ext2_file_handle *fd, uint64_t inode) {
|
|
if (inode == 0)
|
|
return false;
|
|
|
|
struct ext2_superblock *sb = &fd->sb;
|
|
|
|
//determine if we need to use 64 bit inode ids
|
|
bool bit64 = false;
|
|
if (sb->s_rev_level != 0
|
|
&& (sb->s_feature_incompat & (EXT2_IF_64BIT))
|
|
&& sb->group_desc_size != 0
|
|
&& ((sb->group_desc_size & (sb->group_desc_size - 1)) == 0)) {
|
|
if(sb->group_desc_size > 32) {
|
|
bit64 = true;
|
|
}
|
|
}
|
|
|
|
const uint64_t ino_blk_grp = (inode - 1) / sb->s_inodes_per_group;
|
|
const uint64_t ino_tbl_idx = (inode - 1) % sb->s_inodes_per_group;
|
|
|
|
const uint64_t block_size = ((uint64_t)1024 << sb->s_log_block_size);
|
|
uint64_t ino_offset;
|
|
const uint64_t bgd_start_offset = block_size >= 2048 ? block_size : block_size * 2;
|
|
const uint64_t ino_size = sb->s_rev_level == 0 ? sizeof(struct ext2_inode) : sb->s_inode_size;
|
|
|
|
if (!bit64) {
|
|
struct ext2_bgd target_descriptor;
|
|
const uint64_t bgd_offset = bgd_start_offset + (sizeof(struct ext2_bgd) * ino_blk_grp);
|
|
|
|
volume_read(fd->part, &target_descriptor, bgd_offset, sizeof(struct ext2_bgd));
|
|
|
|
ino_offset = ((target_descriptor.bg_inode_table) * block_size) +
|
|
(ino_size * ino_tbl_idx);
|
|
} else {
|
|
struct ext4_bgd target_descriptor;
|
|
const uint64_t bgd_offset = bgd_start_offset + (sizeof(struct ext4_bgd) * ino_blk_grp);
|
|
|
|
volume_read(fd->part, &target_descriptor, bgd_offset, sizeof(struct ext4_bgd));
|
|
|
|
ino_offset = ((target_descriptor.bg_inode_table | (bit64 ? ((uint64_t)target_descriptor.inode_id_hi << 32) : 0)) * block_size) +
|
|
(ino_size * ino_tbl_idx);
|
|
}
|
|
|
|
volume_read(fd->part, ret, ino_offset, sizeof(struct ext2_inode));
|
|
|
|
return true;
|
|
}
|
|
|
|
static uint32_t *create_alloc_map(struct ext2_file_handle *fd,
|
|
struct ext2_inode *inode) {
|
|
if (inode->i_flags & EXT4_EXTENTS_FLAG)
|
|
return NULL;
|
|
|
|
size_t entries_per_block = fd->block_size / sizeof(uint32_t);
|
|
|
|
// Cache the map of blocks
|
|
uint32_t *alloc_map = ext_mem_alloc(inode->i_blocks_count * sizeof(uint32_t));
|
|
for (uint32_t i = 0; i < inode->i_blocks_count; i++) {
|
|
uint32_t block = i;
|
|
if (block < 12) {
|
|
// Direct block
|
|
alloc_map[i] = inode->i_blocks[block];
|
|
} else {
|
|
// Indirect block
|
|
block -= 12;
|
|
if (block >= entries_per_block) {
|
|
// Double indirect block
|
|
block -= entries_per_block;
|
|
uint32_t index = block / entries_per_block;
|
|
uint32_t indirect_block;
|
|
if (index >= entries_per_block) {
|
|
uint32_t first_index = index / entries_per_block;
|
|
uint32_t first_indirect_block;
|
|
volume_read(
|
|
fd->part, &first_indirect_block,
|
|
inode->i_blocks[14] * fd->block_size + first_index * sizeof(uint32_t),
|
|
sizeof(uint32_t)
|
|
);
|
|
uint32_t second_index = index % entries_per_block;
|
|
volume_read(
|
|
fd->part, &indirect_block,
|
|
first_indirect_block * fd->block_size + second_index * sizeof(uint32_t),
|
|
sizeof(uint32_t)
|
|
);
|
|
} else {
|
|
volume_read(
|
|
fd->part, &indirect_block,
|
|
inode->i_blocks[13] * fd->block_size + index * sizeof(uint32_t),
|
|
sizeof(uint32_t)
|
|
);
|
|
}
|
|
for (uint32_t j = 0; j < entries_per_block; j++) {
|
|
if (i + j >= inode->i_blocks_count)
|
|
return alloc_map;
|
|
volume_read(
|
|
fd->part, &alloc_map[i + j],
|
|
indirect_block * fd->block_size + j * sizeof(uint32_t),
|
|
sizeof(uint32_t)
|
|
);
|
|
}
|
|
i += entries_per_block - 1;
|
|
} else {
|
|
// Single indirect block
|
|
volume_read(
|
|
fd->part, &alloc_map[i],
|
|
inode->i_blocks[12] * fd->block_size + block * sizeof(uint32_t),
|
|
sizeof(uint32_t)
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
return alloc_map;
|
|
}
|
|
|
|
static bool symlink_to_inode(struct ext2_inode *inode, struct ext2_file_handle *fd) {
|
|
// I cannot find whether this is 0-terminated or not, so I'm gonna take the
|
|
// safe route here and assume it is not.
|
|
if (inode->i_size < 59) {
|
|
struct ext2_dir_entry dir;
|
|
char *symlink = (char *)inode->i_blocks;
|
|
symlink[59] = 0;
|
|
if (!ext2_parse_dirent(&dir, fd, symlink))
|
|
return false;
|
|
ext2_get_inode(inode, fd, dir.inode);
|
|
return true;
|
|
} else {
|
|
print("ext2: Symlinks with destination paths longer than 60 chars unsupported\n");
|
|
return false;
|
|
}
|
|
}
|
|
|
|
static bool ext2_parse_dirent(struct ext2_dir_entry *dir, struct ext2_file_handle *fd, const char *path) {
|
|
if (*path == '/')
|
|
path++;
|
|
|
|
struct ext2_inode current_inode = fd->root_inode;
|
|
|
|
bool escape = false;
|
|
static char token[256];
|
|
|
|
bool ret;
|
|
|
|
next:
|
|
memset(token, 0, 256);
|
|
|
|
for (size_t i = 0; i < 255 && *path != '/' && *path != '\0'; i++, path++)
|
|
token[i] = *path;
|
|
|
|
if (*path == '\0')
|
|
escape = true;
|
|
else
|
|
path++;
|
|
|
|
uint32_t *alloc_map = create_alloc_map(fd, ¤t_inode);
|
|
|
|
for (uint32_t i = 0; i < current_inode.i_size; ) {
|
|
// preliminary read
|
|
inode_read(dir, i, sizeof(struct ext2_dir_entry),
|
|
¤t_inode, fd, alloc_map);
|
|
|
|
// name read
|
|
char name[dir->name_len + 1];
|
|
|
|
memset(name, 0, dir->name_len + 1);
|
|
inode_read(name, i + sizeof(struct ext2_dir_entry), dir->name_len,
|
|
¤t_inode, fd, alloc_map);
|
|
|
|
if (!strcmp(token, name)) {
|
|
if (escape) {
|
|
ret = true;
|
|
goto out;
|
|
} else {
|
|
// update the current inode
|
|
ext2_get_inode(¤t_inode, fd, dir->inode);
|
|
while ((current_inode.i_mode & FMT_MASK) != S_IFDIR) {
|
|
if ((current_inode.i_mode & FMT_MASK) == S_IFLNK) {
|
|
if (!symlink_to_inode(¤t_inode, fd)) {
|
|
ret = false;
|
|
goto out;
|
|
}
|
|
} else {
|
|
print("ext2: Part of path is not directory nor symlink\n");
|
|
ret = false;
|
|
goto out;
|
|
}
|
|
}
|
|
pmm_free(alloc_map, current_inode.i_blocks_count * sizeof(uint32_t));
|
|
goto next;
|
|
}
|
|
}
|
|
|
|
i += dir->rec_len;
|
|
}
|
|
|
|
ret = false;
|
|
|
|
out:
|
|
pmm_free(alloc_map, current_inode.i_blocks_count * sizeof(uint32_t));
|
|
return ret;
|
|
}
|
|
|
|
bool ext2_open(struct ext2_file_handle *ret, struct volume *part, const char *path) {
|
|
ret->part = part;
|
|
|
|
volume_read(ret->part, &ret->sb, 1024, sizeof(struct ext2_superblock));
|
|
|
|
struct ext2_superblock *sb = &ret->sb;
|
|
|
|
if (sb->s_rev_level != 0 &&
|
|
(sb->s_feature_incompat & EXT2_IF_COMPRESSION ||
|
|
sb->s_feature_incompat & EXT2_IF_INLINE_DATA ||
|
|
sb->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG ||
|
|
sb->s_feature_incompat & EXT2_IF_ENCRYPT)) {
|
|
print("ext2: filesystem has unsupported features %x\n", sb->s_feature_incompat);
|
|
return false;
|
|
}
|
|
|
|
if (sb->s_state == EXT2_FS_UNRECOVERABLE_ERRORS) {
|
|
print("ext2: unrecoverable errors found\n");
|
|
return false;
|
|
}
|
|
|
|
ret->block_size = ((uint64_t)1024 << ret->sb.s_log_block_size);
|
|
|
|
ext2_get_inode(&ret->root_inode, ret, 2);
|
|
|
|
struct ext2_dir_entry entry;
|
|
|
|
if (!ext2_parse_dirent(&entry, ret, path))
|
|
return false;
|
|
|
|
ext2_get_inode(&ret->inode, ret, entry.inode);
|
|
|
|
while ((ret->inode.i_mode & FMT_MASK) != S_IFREG) {
|
|
if ((ret->inode.i_mode & FMT_MASK) == S_IFLNK) {
|
|
if (!symlink_to_inode(&ret->inode, ret))
|
|
return false;
|
|
} else {
|
|
print("ext2: Entity is not regular file nor symlink\n");
|
|
return false;
|
|
}
|
|
}
|
|
|
|
ret->size = ret->inode.i_size;
|
|
|
|
ret->alloc_map = create_alloc_map(ret, &ret->inode);
|
|
|
|
return true;
|
|
}
|
|
|
|
void ext2_close(struct ext2_file_handle *file) {
|
|
if (file->alloc_map != NULL) {
|
|
pmm_free(file->alloc_map, file->inode.i_blocks_count * sizeof(uint32_t));
|
|
}
|
|
pmm_free(file, sizeof(struct ext2_file_handle));
|
|
}
|
|
|
|
void ext2_read(struct ext2_file_handle *file, void *buf, uint64_t loc, uint64_t count) {
|
|
inode_read(buf, loc, count, &file->inode, file, file->alloc_map);
|
|
}
|
|
|
|
static struct ext4_extent_header *ext4_find_leaf(struct ext4_extent_header *ext_block, uint32_t read_block, uint64_t block_size, struct volume *part) {
|
|
struct ext4_extent_idx *index;
|
|
|
|
void *buf = ext_mem_alloc(block_size);
|
|
memcpy(buf, ext_block, block_size);
|
|
ext_block = buf;
|
|
|
|
for (;;) {
|
|
index = (struct ext4_extent_idx *)((size_t)ext_block + 12);
|
|
|
|
#define EXT4_EXT_MAGIC 0xf30a
|
|
if (ext_block->magic != EXT4_EXT_MAGIC)
|
|
panic(false, "invalid extent magic");
|
|
|
|
if (ext_block->depth == 0) {
|
|
return ext_block;
|
|
}
|
|
|
|
int i;
|
|
for (i = 0; i < ext_block->entries; i++) {
|
|
if (read_block < index[i].block)
|
|
break;
|
|
}
|
|
|
|
if (--i < 0)
|
|
panic(false, "extent not found");
|
|
|
|
uint64_t block = ((uint64_t)index[i].leaf_hi << 32) | index[i].leaf;
|
|
|
|
volume_read(part, buf, (block * block_size), block_size);
|
|
ext_block = buf;
|
|
}
|
|
}
|
|
|
|
static int inode_read(void *buf, uint64_t loc, uint64_t count,
|
|
struct ext2_inode *inode, struct ext2_file_handle *fd,
|
|
uint32_t *alloc_map) {
|
|
for (uint64_t progress = 0; progress < count;) {
|
|
uint64_t block = (loc + progress) / fd->block_size;
|
|
|
|
uint64_t chunk = count - progress;
|
|
uint64_t offset = (loc + progress) % fd->block_size;
|
|
if (chunk > fd->block_size - offset)
|
|
chunk = fd->block_size - offset;
|
|
|
|
uint32_t block_index;
|
|
|
|
if (inode->i_flags & EXT4_EXTENTS_FLAG) {
|
|
struct ext4_extent_header *leaf;
|
|
struct ext4_extent *ext;
|
|
int i;
|
|
|
|
leaf = ext4_find_leaf((struct ext4_extent_header *)inode->i_blocks, block, fd->block_size, fd->part);
|
|
|
|
if (!leaf)
|
|
panic(false, "invalid extent");
|
|
ext = (struct ext4_extent*)((size_t)leaf + 12);
|
|
|
|
for (i = 0; i < leaf->entries; i++) {
|
|
if (block < ext[i].block) {
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (--i >= 0) {
|
|
block -= ext[i].block;
|
|
if (block >= ext[i].len) {
|
|
panic(false, "block longer than extent");
|
|
} else {
|
|
uint64_t start = ((uint64_t)ext[i].start_hi << 32) + ext[i].start;
|
|
block_index = start + block;
|
|
}
|
|
} else {
|
|
panic(false, "extent for block not found");
|
|
}
|
|
|
|
pmm_free(leaf, fd->block_size);
|
|
} else {
|
|
block_index = alloc_map[block];
|
|
}
|
|
|
|
volume_read(fd->part, buf + progress, (block_index * fd->block_size) + offset, chunk);
|
|
|
|
progress += chunk;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int ext2_check_signature(struct volume *part) {
|
|
struct ext2_superblock sb;
|
|
volume_read(part, &sb, 1024, sizeof(struct ext2_superblock));
|
|
|
|
if (sb.s_magic != EXT2_S_MAGIC)
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
bool ext2_get_guid(struct guid *guid, struct volume *part) {
|
|
struct ext2_superblock sb;
|
|
volume_read(part, &sb, 1024, sizeof(struct ext2_superblock));
|
|
|
|
if (sb.s_magic != EXT2_S_MAGIC)
|
|
return false;
|
|
|
|
((uint64_t *)guid)[0] = sb.s_uuid[0];
|
|
((uint64_t *)guid)[1] = sb.s_uuid[1];
|
|
|
|
return true;
|
|
}
|