687 lines
20 KiB
C
687 lines
20 KiB
C
#include <stdint.h>
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#include <stddef.h>
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#include <stdbool.h>
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#include <fs/ext2.h>
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#include <drivers/disk.h>
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#include <lib/libc.h>
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#include <lib/misc.h>
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#include <lib/print.h>
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#include <mm/pmm.h>
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/* Superblock Fields */
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struct ext2_superblock {
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uint32_t s_inodes_count;
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uint32_t s_blocks_count;
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uint32_t s_r_blocks_count;
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uint32_t s_free_blocks_count;
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uint32_t s_free_inodes_count;
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uint32_t s_first_data_block;
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uint32_t s_log_block_size;
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uint32_t s_log_frag_size;
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uint32_t s_blocks_per_group;
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uint32_t s_frags_per_group;
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uint32_t s_inodes_per_group;
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uint32_t s_mtime;
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uint32_t s_wtime;
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uint16_t s_mnt_count;
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uint16_t s_max_mnt_count;
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uint16_t s_magic;
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uint16_t s_state;
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uint16_t s_errors;
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uint16_t s_minor_rev_level;
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uint32_t s_lastcheck;
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uint32_t s_checkinterval;
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uint32_t s_creator_os;
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uint32_t s_rev_level;
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uint16_t s_def_resuid;
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uint16_t s_def_gid;
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// if version number >= 1, we have to use the ext2 extended superblock as well
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/* Extended Superblock */
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uint32_t s_first_ino;
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uint16_t s_inode_size;
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uint16_t s_block_group_nr;
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uint32_t s_feature_compat;
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uint32_t s_feature_incompat;
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uint32_t s_feature_ro_compat;
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uint64_t s_uuid[2];
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uint8_t s_volume_name[16];
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uint64_t s_last_mounted[8];
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uint32_t compression_info;
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uint8_t prealloc_blocks;
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uint8_t prealloc_dir_blocks;
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uint16_t reserved_gdt_blocks;
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uint8_t journal_uuid[16];
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uint32_t journal_inum;
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uint32_t journal_dev;
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uint32_t last_orphan;
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uint32_t hash_seed[4];
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uint8_t def_hash_version;
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uint8_t jnl_backup_type;
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uint16_t group_desc_size;
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uint32_t default_mount_opts;
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uint32_t first_meta_bg;
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uint32_t mkfs_time;
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uint32_t jnl_blocks[17];
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} __attribute__((packed));
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struct ext2_linux {
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uint8_t frag_num;
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uint8_t frag_size;
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uint16_t reserved_16;
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uint16_t user_id_high;
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uint16_t group_id_high;
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uint32_t reserved_32;
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} __attribute__((packed));
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struct ext2_inode {
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uint16_t i_mode;
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uint16_t i_uid;
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uint32_t i_size;
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uint32_t i_atime;
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uint32_t i_ctime;
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uint32_t i_mtime;
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uint32_t i_dtime;
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uint16_t i_gid;
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uint16_t i_links_count;
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uint32_t i_blocks_count;
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uint32_t i_flags;
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uint32_t i_osd1;
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uint32_t i_blocks[15];
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uint32_t i_generation;
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/* EXT2 v >= 1.0 */
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uint32_t i_eab;
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uint32_t i_maj;
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/* EXT2 vAll */
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uint32_t i_frag_block;
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struct ext2_linux i_osd2;
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} __attribute__((packed));
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struct ext2_file_handle {
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struct volume *part;
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struct ext2_superblock sb;
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int size;
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struct ext2_inode root_inode;
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struct ext2_inode inode;
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uint64_t block_size;
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uint32_t *alloc_map;
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};
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/* Inode types */
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#define S_IFIFO 0x1000
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#define S_IFCHR 0x2000
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#define S_IFDIR 0x4000
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#define S_IFBLK 0x6000
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#define S_IFREG 0x8000
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#define S_IFLNK 0xa000
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#define S_IFSOCK 0xc000
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#define FMT_MASK 0xf000
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/* EXT2 Filesystem States */
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#define EXT2_FS_UNRECOVERABLE_ERRORS 3
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/* Ext2 incompatible features */
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#define EXT2_IF_COMPRESSION 0x01
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#define EXT2_IF_EXTENTS 0x40
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#define EXT2_IF_64BIT 0x80
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#define EXT2_IF_INLINE_DATA 0x8000
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#define EXT2_IF_ENCRYPT 0x10000
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#define EXT2_FEATURE_INCOMPAT_META_BG 0x0010
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/* Ext4 flags */
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#define EXT4_EXTENTS_FLAG 0x80000
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#define EXT2_S_MAGIC 0xEF53
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/* EXT2 Block Group Descriptor */
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struct ext2_bgd {
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uint32_t bg_block_bitmap;
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uint32_t bg_inode_bitmap;
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uint32_t bg_inode_table;
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uint16_t bg_free_blocks_count;
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uint16_t bg_free_inodes_count;
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uint16_t bg_dirs_count;
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uint16_t reserved[7];
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} __attribute__((packed));
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struct ext4_bgd {
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uint32_t bg_block_bitmap;
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uint32_t bg_inode_bitmap;
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uint32_t bg_inode_table;
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uint16_t bg_free_blocks_count;
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uint16_t bg_free_inodes_count;
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uint16_t bg_dirs_count;
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uint16_t pad;
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uint32_t reserved[3];
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uint32_t block_id_hi;
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uint32_t inode_id_hi;
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uint32_t inode_table_id_hi;
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uint16_t free_blocks_hi;
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uint16_t free_inodes_hi;
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uint16_t used_dirs_hi;
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uint16_t pad2;
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uint32_t reserved2[3];
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} __attribute__((packed));
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/* EXT2 Inode Types */
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#define EXT2_INO_DIRECTORY 0x4000
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/* EXT2 Directory Entry */
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struct ext2_dir_entry {
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uint32_t inode;
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uint16_t rec_len;
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uint8_t name_len;
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uint8_t type;
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} __attribute__((packed));
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struct ext4_extent_header {
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uint16_t magic;
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uint16_t entries;
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uint16_t max;
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uint16_t depth;
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uint16_t generation;
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} __attribute__((packed));
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struct ext4_extent {
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uint32_t block;
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uint16_t len;
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uint16_t start_hi;
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uint32_t start;
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} __attribute__((packed));
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struct ext4_extent_idx {
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uint32_t block;
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uint32_t leaf;
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uint16_t leaf_hi;
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uint16_t empty;
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} __attribute__((packed));
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static int inode_read(void *buf, uint64_t loc, uint64_t count,
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struct ext2_inode *inode, struct ext2_file_handle *fd,
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uint32_t *alloc_map);
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static bool ext2_parse_dirent(struct ext2_dir_entry *dir, struct ext2_file_handle *fd, const char *path);
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// parse an inode given the partition base and inode number
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static bool ext2_get_inode(struct ext2_inode *ret,
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struct ext2_file_handle *fd, uint64_t inode) {
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if (inode == 0)
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return false;
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struct ext2_superblock *sb = &fd->sb;
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//determine if we need to use 64 bit inode ids
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bool bit64 = false;
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if (sb->s_rev_level != 0
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&& (sb->s_feature_incompat & (EXT2_IF_64BIT))
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&& sb->group_desc_size != 0
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&& ((sb->group_desc_size & (sb->group_desc_size - 1)) == 0)) {
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if(sb->group_desc_size > 32) {
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bit64 = true;
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}
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}
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const uint64_t ino_blk_grp = (inode - 1) / sb->s_inodes_per_group;
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const uint64_t ino_tbl_idx = (inode - 1) % sb->s_inodes_per_group;
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const uint64_t block_size = ((uint64_t)1024 << sb->s_log_block_size);
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uint64_t ino_offset;
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const uint64_t bgd_start_offset = block_size >= 2048 ? block_size : block_size * 2;
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const uint64_t ino_size = sb->s_rev_level == 0 ? sizeof(struct ext2_inode) : sb->s_inode_size;
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if (!bit64) {
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struct ext2_bgd target_descriptor;
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const uint64_t bgd_offset = bgd_start_offset + (sizeof(struct ext2_bgd) * ino_blk_grp);
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volume_read(fd->part, &target_descriptor, bgd_offset, sizeof(struct ext2_bgd));
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ino_offset = ((target_descriptor.bg_inode_table) * block_size) +
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(ino_size * ino_tbl_idx);
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} else {
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struct ext4_bgd target_descriptor;
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const uint64_t bgd_offset = bgd_start_offset + (sizeof(struct ext4_bgd) * ino_blk_grp);
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volume_read(fd->part, &target_descriptor, bgd_offset, sizeof(struct ext4_bgd));
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ino_offset = ((target_descriptor.bg_inode_table | (bit64 ? ((uint64_t)target_descriptor.inode_id_hi << 32) : 0)) * block_size) +
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(ino_size * ino_tbl_idx);
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}
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volume_read(fd->part, ret, ino_offset, sizeof(struct ext2_inode));
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return true;
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}
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static uint32_t *create_alloc_map(struct ext2_file_handle *fd,
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struct ext2_inode *inode) {
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if (inode->i_flags & EXT4_EXTENTS_FLAG)
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return NULL;
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size_t entries_per_block = fd->block_size / sizeof(uint32_t);
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// Cache the map of blocks
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uint32_t *alloc_map = ext_mem_alloc(inode->i_blocks_count * sizeof(uint32_t));
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for (uint32_t i = 0; i < inode->i_blocks_count; i++) {
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uint32_t block = i;
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if (block < 12) {
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// Direct block
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alloc_map[i] = inode->i_blocks[block];
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} else {
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// Indirect block
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block -= 12;
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if (block >= entries_per_block) {
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// Double indirect block
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block -= entries_per_block;
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uint32_t index = block / entries_per_block;
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uint32_t indirect_block;
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if (index >= entries_per_block) {
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uint32_t first_index = index / entries_per_block;
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uint32_t first_indirect_block;
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volume_read(
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fd->part, &first_indirect_block,
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inode->i_blocks[14] * fd->block_size + first_index * sizeof(uint32_t),
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sizeof(uint32_t)
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);
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uint32_t second_index = index % entries_per_block;
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volume_read(
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fd->part, &indirect_block,
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first_indirect_block * fd->block_size + second_index * sizeof(uint32_t),
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sizeof(uint32_t)
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);
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} else {
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volume_read(
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fd->part, &indirect_block,
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inode->i_blocks[13] * fd->block_size + index * sizeof(uint32_t),
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sizeof(uint32_t)
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);
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}
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for (uint32_t j = 0; j < entries_per_block; j++) {
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if (i + j >= inode->i_blocks_count)
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return alloc_map;
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volume_read(
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fd->part, &alloc_map[i + j],
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indirect_block * fd->block_size + j * sizeof(uint32_t),
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sizeof(uint32_t)
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);
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}
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i += entries_per_block - 1;
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} else {
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// Single indirect block
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volume_read(
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fd->part, &alloc_map[i],
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inode->i_blocks[12] * fd->block_size + block * sizeof(uint32_t),
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sizeof(uint32_t)
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);
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}
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}
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}
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return alloc_map;
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}
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static bool symlink_to_inode(struct ext2_inode *inode, struct ext2_file_handle *fd,
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const char *cwd, size_t cwd_len) {
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// I cannot find whether this is 0-terminated or not, so I'm gonna take the
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// safe route here and assume it is not.
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if (inode->i_size < 59) {
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struct ext2_dir_entry dir;
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char *symlink = (char *)inode->i_blocks;
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symlink[59] = 0;
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char *abs = ext_mem_alloc(4096);
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char *cwd_copy = ext_mem_alloc(cwd_len + 1);
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memcpy(cwd_copy, cwd, cwd_len);
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get_absolute_path(abs, symlink, cwd_copy);
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pmm_free(cwd_copy, cwd_len + 1);
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if (!ext2_parse_dirent(&dir, fd, abs)) {
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pmm_free(abs, 4096);
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return false;
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}
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pmm_free(abs, 4096);
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ext2_get_inode(inode, fd, dir.inode);
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return true;
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} else {
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print("ext2: Symlinks with destination paths longer than 60 chars unsupported\n");
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return false;
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}
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}
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static bool ext2_parse_dirent(struct ext2_dir_entry *dir, struct ext2_file_handle *fd, const char *path) {
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if (*path != '/') {
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panic(true, "ext2: Path does not start in /");
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}
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path++;
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struct ext2_inode current_inode = fd->root_inode;
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bool escape = false;
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static char token[256];
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bool ret;
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const char *cwd = path - 1; // because /
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size_t cwd_len = 1;
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size_t next_cwd_len = cwd_len;
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next:
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memset(token, 0, 256);
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for (size_t i = 0; i < 255 && *path != '/' && *path != '\0'; i++, path++, next_cwd_len++)
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token[i] = *path;
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if (*path == '\0')
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escape = true;
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else
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path++, next_cwd_len++;
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uint32_t *alloc_map = create_alloc_map(fd, ¤t_inode);
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for (uint32_t i = 0; i < current_inode.i_size; ) {
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// preliminary read
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inode_read(dir, i, sizeof(struct ext2_dir_entry),
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¤t_inode, fd, alloc_map);
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// name read
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char *name = ext_mem_alloc(dir->name_len + 1);
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memset(name, 0, dir->name_len + 1);
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inode_read(name, i + sizeof(struct ext2_dir_entry), dir->name_len,
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¤t_inode, fd, alloc_map);
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int (*strcmpfn)(const char *, const char *) = case_insensitive_fopen ? strcasecmp : strcmp;
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int test = strcmpfn(token, name);
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pmm_free(name, dir->name_len + 1);
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if (test == 0) {
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if (escape) {
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ret = true;
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goto out;
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} else {
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// update the current inode
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ext2_get_inode(¤t_inode, fd, dir->inode);
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while ((current_inode.i_mode & FMT_MASK) != S_IFDIR) {
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if ((current_inode.i_mode & FMT_MASK) == S_IFLNK) {
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if (!symlink_to_inode(¤t_inode, fd, cwd, cwd_len)) {
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ret = false;
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goto out;
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}
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} else {
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print("ext2: Part of path is not directory nor symlink\n");
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ret = false;
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goto out;
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}
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}
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pmm_free(alloc_map, current_inode.i_blocks_count * sizeof(uint32_t));
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cwd_len = next_cwd_len;
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goto next;
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}
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}
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i += dir->rec_len;
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}
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ret = false;
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out:
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pmm_free(alloc_map, current_inode.i_blocks_count * sizeof(uint32_t));
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return ret;
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}
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static void ext2_read(struct file_handle *handle, void *buf, uint64_t loc, uint64_t count);
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static void ext2_close(struct file_handle *file);
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struct file_handle *ext2_open(struct volume *part, const char *path) {
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struct ext2_file_handle *ret = ext_mem_alloc(sizeof(struct ext2_file_handle));
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ret->part = part;
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volume_read(ret->part, &ret->sb, 1024, sizeof(struct ext2_superblock));
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struct ext2_superblock *sb = &ret->sb;
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if (sb->s_magic != EXT2_S_MAGIC) {
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pmm_free(ret, sizeof(struct ext2_file_handle));
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return NULL;
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}
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if (sb->s_rev_level != 0 &&
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(sb->s_feature_incompat & EXT2_IF_COMPRESSION ||
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sb->s_feature_incompat & EXT2_IF_INLINE_DATA ||
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sb->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)) {
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print("ext2: filesystem has unsupported features %x\n", sb->s_feature_incompat);
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pmm_free(ret, sizeof(struct ext2_file_handle));
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return NULL;
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}
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if (sb->s_rev_level != 0 && sb->s_feature_incompat & EXT2_IF_ENCRYPT) {
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print("ext2: WARNING: File system has encryption feature on, stuff may misbehave\n");
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}
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if (sb->s_state == EXT2_FS_UNRECOVERABLE_ERRORS) {
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print("ext2: unrecoverable errors found\n");
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pmm_free(ret, sizeof(struct ext2_file_handle));
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return NULL;
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}
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ret->block_size = ((uint64_t)1024 << ret->sb.s_log_block_size);
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ext2_get_inode(&ret->root_inode, ret, 2);
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struct ext2_dir_entry entry;
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size_t cwd_len = 0;
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char *cwd = ext_mem_alloc(4096);
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for (int i = strlen(path) - 1; i > 0; i--) {
|
|
if (path[i] == '/' || path[i] == 0) {
|
|
cwd_len = i;
|
|
break;
|
|
}
|
|
}
|
|
memcpy(cwd, path, cwd_len);
|
|
|
|
if (!ext2_parse_dirent(&entry, ret, path)) {
|
|
pmm_free(cwd, 4096);
|
|
pmm_free(ret, sizeof(struct ext2_file_handle));
|
|
return NULL;
|
|
}
|
|
|
|
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, cwd, cwd_len)) {
|
|
pmm_free(cwd, 4096);
|
|
pmm_free(ret, sizeof(struct ext2_file_handle));
|
|
return NULL;
|
|
}
|
|
} else {
|
|
print("ext2: Entity is not regular file nor symlink\n");
|
|
pmm_free(cwd, 4096);
|
|
pmm_free(ret, sizeof(struct ext2_file_handle));
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
pmm_free(cwd, 4096);
|
|
|
|
ret->size = ret->inode.i_size;
|
|
|
|
ret->alloc_map = create_alloc_map(ret, &ret->inode);
|
|
|
|
struct file_handle *handle = ext_mem_alloc(sizeof(struct file_handle));
|
|
|
|
handle->fd = ret;
|
|
handle->read = (void *)ext2_read;
|
|
handle->close = (void *)ext2_close;
|
|
handle->size = ret->size;
|
|
handle->vol = part;
|
|
#if defined (UEFI)
|
|
handle->efi_part_handle = part->efi_part_handle;
|
|
#endif
|
|
|
|
return handle;
|
|
}
|
|
|
|
static void ext2_close(struct file_handle *file) {
|
|
struct ext2_file_handle *f = file->fd;
|
|
if (f->alloc_map != NULL) {
|
|
pmm_free(f->alloc_map, f->inode.i_blocks_count * sizeof(uint32_t));
|
|
}
|
|
pmm_free(f, sizeof(struct ext2_file_handle));
|
|
pmm_free(file, sizeof(struct file_handle));
|
|
}
|
|
|
|
static void ext2_read(struct file_handle *file, void *buf, uint64_t loc, uint64_t count) {
|
|
struct ext2_file_handle *f = file->fd;
|
|
inode_read(buf, loc, count, &f->inode, f, f->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;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
char *ext2_get_label(struct volume *part) {
|
|
struct ext2_superblock sb;
|
|
volume_read(part, &sb, 1024, sizeof(struct ext2_superblock));
|
|
|
|
if (sb.s_magic != EXT2_S_MAGIC) {
|
|
return NULL;
|
|
}
|
|
|
|
if (sb.s_rev_level < 1) {
|
|
return NULL;
|
|
}
|
|
|
|
size_t label_len = strlen((char *)sb.s_volume_name);
|
|
if (label_len == 0) {
|
|
return NULL;
|
|
}
|
|
char *ret = ext_mem_alloc(label_len + 1);
|
|
strcpy(ret, (char *)sb.s_volume_name);
|
|
|
|
return ret;
|
|
}
|