pjht/ext2_parser
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Simple cli

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pjht 2018-11-11 14:40:09 -06:00
parent 7e632f51bd
commit 66cb5cf441
2 changed files with 111 additions and 34 deletions
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1
ext2_structs.h
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@ -133,5 +133,6 @@ typedef struct {
uint16_t rec_len;
char name_len;
char file_type;
char file_name[1];
} __attribute__((packed)) dir_entry;
#endif

144
main.c
View File

@ -2,6 +2,7 @@
#include <stdint.h>
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include "ext2_structs.h"
char img[33554432];
ext2_superblock* supblk;
@ -129,6 +130,65 @@ inode read_inode(uint32_t inode_num) {
return inodes[index];
}
char** get_dir_listing(uint32_t inode_num) {
char** names=malloc(sizeof(char*)*100);
int num_entries_used=0;
int max_len=100;
inode dir_inode=read_inode(inode_num);
uint32_t size=dir_inode.i_size;
uint32_t tot_size=0;
dir_entry* dir=read_blk(dir_inode.i_block[0]);
dir_entry* current_entry=dir;
for(int i=0;tot_size<size;i++) {
if (current_entry->file_type==0) {
break;
}
if(num_entries_used==max_len) {
max_len+=100;
names=realloc(names,sizeof(char*)*max_len);
}
names[num_entries_used]=malloc(current_entry->name_len+1);
strcpy(names[num_entries_used],current_entry->file_name);
num_entries_used++;
tot_size+=current_entry->rec_len;
current_entry=(dir_entry*)(((uint64_t)current_entry)+current_entry->rec_len);
}
if(num_entries_used==max_len) {
max_len+=1;
names=realloc(names,sizeof(char*)*max_len);
}
names[num_entries_used]=NULL;
return names;
}
void free_dir_listing(char** names) {
for(int i=0;names[i]!=NULL;i++) {
free(names[i]);
}
free(names);
}
dir_entry* read_dir_entry(uint32_t inode_num,uint32_t dir_entry_num) {
inode dir_inode=read_inode(inode_num);
uint32_t size=dir_inode.i_size;
uint32_t tot_size=0;
uint32_t ent_num=0;
dir_entry* dir=read_blk(dir_inode.i_block[0]);
dir_entry* current_entry=dir;
for(int i=0;tot_size<size;i++) {
if (current_entry->file_type==0) {
break;
}
if(ent_num==dir_entry_num) {
return current_entry;
}
ent_num++;
tot_size+=current_entry->rec_len;
current_entry=(dir_entry*)(((uint64_t)current_entry)+current_entry->rec_len);
}
return NULL;
}
int main() {
FILE* f=fopen("ext2.img","rb");
if (f) {
@ -148,40 +208,56 @@ int main() {
printf("Number of unallocated inodes:%d\n",blk_group->bg_free_inodes_count);
blk_grps[i]=blk_group;
blk_group++;
}
printf("root dir:\n");
inode root_dir_inode=read_inode(2);
show_inode_info(root_dir_inode);
dir_entry* root_dir=read_blk(root_dir_inode.i_block[0]);
dir_entry* current_entry=root_dir;
for(int i=0;;i++) {
if (current_entry->file_type==0) {
break;
};
uint32_t cwi=2;
while(1) {
printf(">");
char cmd[256];
fgets(cmd,256,stdin);
cmd[strlen(cmd)-1]='\0';
if (strcmp(cmd,"ls")==0) {
char** names=get_dir_listing(cwi);
for(int i=0;names[i]!=NULL;i++) {
printf("%s ",names[i]);
}
printf("\n");
free_dir_listing(names);
} else {
uint32_t inode;
char got_inode=0;
char** names=get_dir_listing(cwi);
for(int i=0;names[i]!=NULL;i++) {
if (strcmp(names[i],cmd)==0) {
dir_entry* entry=read_dir_entry(2,i);
inode=entry->inode;
got_inode=1;
break;
}
}
free_dir_listing(names);
if (got_inode) {
printf("Inode for %s:%d\n",cmd,inode);
} else {
printf("No such file or directory %s\n",cmd);
}
}
printf("Directory entry %d:\n",i);
printf("Directory entry inode:%d\n",current_entry->inode);
printf("Length of entry:%d\n",current_entry->rec_len);
printf("Length of name:%d\n",current_entry->name_len);
printf("File type:%d\n",current_entry->file_type);
printf("File name:%s\n",(char*)current_entry+sizeof(dir_entry));
current_entry=(dir_entry*)(((uint64_t)current_entry)+current_entry->rec_len);
}
printf("lost+found:\n");
inode lost_dir_inode=read_inode(11);
show_inode_info(lost_dir_inode);
printf("Block:%d\n",lost_dir_inode.i_block[0]);
dir_entry* lost_dir=read_blk(lost_dir_inode.i_block[0]);
current_entry=lost_dir;
for(int i=0;;i++) {
if (current_entry->file_type==0) {
break;
}
printf("Directory entry %d:\n",i);
printf("Directory entry inode:%d\n",current_entry->inode);
printf("Length of entry:%d\n",current_entry->rec_len);
printf("Length of name:%d\n",current_entry->name_len);
printf("File type:%d\n",current_entry->file_type);
printf("File name:%s\n",(char*)current_entry+sizeof(dir_entry));
current_entry=(dir_entry*)(((uint64_t)current_entry)+current_entry->rec_len);
}
// printf("lost+found:\n");
// inode lost_dir_inode=read_inode(11);
// show_inode_info(lost_dir_inode);
// printf("Block:%d\n",lost_dir_inode.i_block[0]);
// dir_entry* lost_dir=read_blk(lost_dir_inode.i_block[0]);
// current_entry=lost_dir;
// for(int i=0;;i++) {
// if (current_entry->file_type==0) {
// break;
// }
// printf("Directory entry %d:\n",i);
// printf("Directory entry inode:%d\n",current_entry->inode);
// printf("Length of entry:%d\n",current_entry->rec_len);
// printf("Length of name:%d\n",current_entry->name_len);
// printf("File type:%d\n",current_entry->file_type);
// printf("File name:%s\n",(char*)current_entry+sizeof(dir_entry));
// current_entry=(dir_entry*)(((uint64_t)current_entry)+current_entry->rec_len);
// }
}