264 lines
7.5 KiB
C
264 lines
7.5 KiB
C
#include <stdio.h>
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#include <stdint.h>
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#include <math.h>
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#include <stdlib.h>
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#include <string.h>
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#include "ext2_structs.h"
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char img[33554432];
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ext2_superblock* supblk;
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uint32_t blk_size;
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blk_grp** blk_grps;
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void show_supblk_info(int num_blk_grps) {
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printf("Num block groups:%d\n",num_blk_grps);
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printf("Number of blocks per group:%d\n",supblk->s_blocks_per_group);
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printf("Number of inodes per group:%d\n",supblk->s_inodes_per_group);
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printf("Number of unallocated blocks:%d\n",supblk->s_free_blocks_count);
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printf("Number of unallocated inodes:%d\n",supblk->s_free_inodes_count);
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printf("Optional features:");
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if ((supblk->s_feature_compat&EXT2_FEATURE_COMPAT_DIR_PREALLOC)!=0) {
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printf("DIR_PREALLOC ");
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}
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if ((supblk->s_feature_compat&EXT2_FEATURE_COMPAT_IMAGIC_INODES)!=0) {
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printf("IMAGIC_INODES ");
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}
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if ((supblk->s_feature_compat&EXT2_FEATURE_COMPAT_HAS_JOURNAL)!=0) {
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printf("HAS_JOURNAL ");
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}
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if ((supblk->s_feature_compat&EXT2_FEATURE_COMPAT_EXT_ATTR)!=0) {
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printf("EXT_ATTR ");
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}
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if ((supblk->s_feature_compat&EXT2_FEATURE_COMPAT_RESIZE_INO)!=0) {
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printf("RESIZE_INO ");
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}
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if ((supblk->s_feature_compat&EXT2_FEATURE_COMPAT_DIR_INDEX)!=0) {
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printf("DIR_INDEX ");
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}
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printf("\n");
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printf("Required features:");
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if ((supblk->s_feature_incompat&EXT2_FEATURE_INCOMPAT_COMPRESSION)!=0) {
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printf("COMPRESSION ");
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}
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if ((supblk->s_feature_incompat&EXT2_FEATURE_INCOMPAT_FILETYPE)!=0) {
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printf("FILETYPE ");
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}
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if ((supblk->s_feature_incompat&EXT2_FEATURE_INCOMPAT_RECOVER)!=0) {
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printf("RECOVER ");
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}
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if ((supblk->s_feature_incompat&EXT2_FEATURE_INCOMPAT_JOURNAL_DEV)!=0) {
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printf("JOURNAL_DEV ");
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}
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printf("\n");
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printf("Readonly features:");
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if ((supblk->s_feature_ro_compat&EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)!=0) {
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printf("SPARSE_SUPER ");
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}
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if ((supblk->s_feature_ro_compat&EXT2_FEATURE_RO_COMPAT_LARGE_FILE)!=0) {
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printf("LARGE_FILE ");
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}
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if ((supblk->s_feature_ro_compat&EXT2_FEATURE_RO_COMPAT_BTREE_DIR)!=0) {
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printf("BTREE_DIR ");
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}
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printf("\n");
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}
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void show_inode_info(inode inod) {
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printf("Flags:");
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if ((inod.i_flags&EXT2_SECRM_FL)!=0) {
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printf("SECRM_FL");
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}
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if ((inod.i_flags&EXT2_UNRM_FL)!=0) {
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printf("UNRM_FL");
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}
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if ((inod.i_flags&EXT2_COMPR_FL)!=0) {
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printf("COMPR_FL");
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}
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if ((inod.i_flags&EXT2_SYNC_FL)!=0) {
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printf("SYNC_FL");
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}
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if ((inod.i_flags&EXT2_IMMUTABLE_FL)!=0) {
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printf("IMMUTABLE_FL");
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}
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if ((inod.i_flags&EXT2_APPEND_FL)!=0) {
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printf("APPEND_FL");
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}
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if ((inod.i_flags&EXT2_NODUMP_FL)!=0) {
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printf("NODUMP_FL");
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}
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if ((inod.i_flags&EXT2_NOATIME_FL)!=0) {
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printf("NOATIME_FL");
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}
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if ((inod.i_flags&EXT2_DIRTY_FL)!=0) {
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printf("DIRTY_FL");
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}
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if ((inod.i_flags&EXT2_COMPRBLK_FL)!=0) {
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printf("COMPRBLK_FL");
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}
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if ((inod.i_flags&EXT2_NOCOMPR_FL)!=0) {
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printf("NOCOMPR_FL");
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}
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if ((inod.i_flags&EXT2_ECOMPR_FL)!=0) {
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printf("ECOMPR_FL");
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}
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if ((inod.i_flags&EXT2_BTREE_FL)!=0) {
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printf("BTREE_FL");
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}
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if ((inod.i_flags&EXT2_INDEX_FL)!=0) {
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printf("INDEX_FL");
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}
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if ((inod.i_flags&EXT2_IMAGIC_FL)!=0) {
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printf("IMAGIC_FL");
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}
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if ((inod.i_flags&EXT2_JOURNAL_DATA_FL)!=0) {
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printf("JOURNAL_DATA_FL");
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}
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if ((inod.i_flags&EXT2_RESERVED_FL)!=0) {
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printf("RESERVED_FL");
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}
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printf("\n");
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}
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void* read_blk(blknum) {
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return (void*)(&img[blknum*1024]);
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}
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inode read_inode(uint32_t inode_num) {
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uint32_t grp=(inode_num-1)/supblk->s_inodes_per_group;
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uint32_t index=(inode_num-1)%supblk->s_inodes_per_group;
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uint32_t starting_blk=blk_grps[grp]->bg_inode_table;
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inode* inodes=read_blk(starting_blk);
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return inodes[index];
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}
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char** get_dir_listing(uint32_t inode_num) {
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char** names=malloc(sizeof(char*)*100);
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int num_entries_used=0;
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int max_len=100;
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inode dir_inode=read_inode(inode_num);
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uint32_t size=dir_inode.i_size;
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uint32_t tot_size=0;
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dir_entry* dir=read_blk(dir_inode.i_block[0]);
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dir_entry* current_entry=dir;
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for(int i=0;tot_size<size;i++) {
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if (current_entry->file_type==0) {
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break;
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}
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if(num_entries_used==max_len) {
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max_len+=100;
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names=realloc(names,sizeof(char*)*max_len);
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}
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names[num_entries_used]=malloc(current_entry->name_len+1);
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strcpy(names[num_entries_used],current_entry->file_name);
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num_entries_used++;
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tot_size+=current_entry->rec_len;
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current_entry=(dir_entry*)(((uint64_t)current_entry)+current_entry->rec_len);
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}
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if(num_entries_used==max_len) {
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max_len+=1;
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names=realloc(names,sizeof(char*)*max_len);
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}
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names[num_entries_used]=NULL;
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return names;
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}
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void free_dir_listing(char** names) {
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for(int i=0;names[i]!=NULL;i++) {
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free(names[i]);
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}
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free(names);
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}
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dir_entry* read_dir_entry(uint32_t inode_num,uint32_t dir_entry_num) {
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inode dir_inode=read_inode(inode_num);
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uint32_t size=dir_inode.i_size;
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uint32_t tot_size=0;
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uint32_t ent_num=0;
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dir_entry* dir=read_blk(dir_inode.i_block[0]);
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dir_entry* current_entry=dir;
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for(int i=0;tot_size<size;i++) {
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if (current_entry->file_type==0) {
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break;
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}
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if(ent_num==dir_entry_num) {
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return current_entry;
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}
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ent_num++;
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tot_size+=current_entry->rec_len;
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current_entry=(dir_entry*)(((uint64_t)current_entry)+current_entry->rec_len);
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}
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return NULL;
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}
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int main() {
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FILE* f=fopen("ext2.img","rb");
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if (f) {
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fread(img,1,32*1024*1024,f);
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fclose(f);
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}
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supblk=read_blk(1);
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blk_size=1024<<(supblk->s_log_blk_size);
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double num_blk_grps_dbl=supblk->s_blocks_count/(double)supblk->s_blocks_per_group;
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uint32_t num_blk_grps=ceil(num_blk_grps_dbl);
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show_supblk_info(num_blk_grps);
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blk_grps=malloc(sizeof(blk_grp*)*num_blk_grps);
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blk_grp* blk_group=read_blk(2);
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for (int i=0;i<num_blk_grps;i++) {
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printf("Block group %d:\n",i);
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printf("Number of unallocated blocks:%d\n",blk_group->bg_free_blocks_count);
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printf("Number of unallocated inodes:%d\n",blk_group->bg_free_inodes_count);
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blk_grps[i]=blk_group;
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blk_group++;
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};
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uint32_t cwi=2;
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while(1) {
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printf(">");
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char cmd[256];
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fgets(cmd,256,stdin);
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cmd[strlen(cmd)-1]='\0';
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if (strcmp(cmd,"ls")==0) {
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char** names=get_dir_listing(cwi);
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for(int i=0;names[i]!=NULL;i++) {
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printf("%s ",names[i]);
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}
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printf("\n");
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free_dir_listing(names);
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} else {
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uint32_t inode;
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char got_inode=0;
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char** names=get_dir_listing(cwi);
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for(int i=0;names[i]!=NULL;i++) {
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if (strcmp(names[i],cmd)==0) {
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dir_entry* entry=read_dir_entry(2,i);
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inode=entry->inode;
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got_inode=1;
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break;
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}
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}
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free_dir_listing(names);
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if (got_inode) {
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printf("Inode for %s:%d\n",cmd,inode);
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} else {
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printf("No such file or directory %s\n",cmd);
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}
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}
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}
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// printf("lost+found:\n");
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// inode lost_dir_inode=read_inode(11);
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// show_inode_info(lost_dir_inode);
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// printf("Block:%d\n",lost_dir_inode.i_block[0]);
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// dir_entry* lost_dir=read_blk(lost_dir_inode.i_block[0]);
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// current_entry=lost_dir;
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// for(int i=0;;i++) {
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// if (current_entry->file_type==0) {
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// break;
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// }
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// printf("Directory entry %d:\n",i);
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// printf("Directory entry inode:%d\n",current_entry->inode);
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// printf("Length of entry:%d\n",current_entry->rec_len);
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// printf("Length of name:%d\n",current_entry->name_len);
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// printf("File type:%d\n",current_entry->file_type);
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// printf("File name:%s\n",(char*)current_entry+sizeof(dir_entry));
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// current_entry=(dir_entry*)(((uint64_t)current_entry)+current_entry->rec_len);
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// }
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}
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