SDB

simple C debugger like gdb

How can I do with SDB ?

support basic debugger usage, like set/delete breakpoint, step by step run instruction, and dump memory content, etc.

Getting started

Compile

# install dependencies
sudo apt-get update
sudo apt-get install libelf-dev
./setup.sh # install capstone from source code

# compile the debugger
make

Run the debugger

# start debugger only
./sdb

# start debugger and load the debug target
./sdb <program_path>

Commands

load path/to/a/program

load a program to the debugger

start

start the program and stop at the first

run

run the program

break address

add a break point at address

delete breakpoint-id

delete a break point by id, which you can get the breakpoint id by list commands

list

list break points and their ids

cont

continue running your program

si

Execute one instruction

disasm address

disassemble instructions in a file or a memory region

dump address length

dump memory content start from address and dump length

vmmap

show memory layout

getregs

get the valus of all registers

all supported register is listed as following

• rax, rbx, rcx, rdx, rbp, rsi, rdi, rip, rsp, eflags
• r8 ~ r15

get reg

get a single value from a register

set reg val

set specific value to a register

help

show the help message

exit

terminate the debugger

Example

$ ./sdb sample/hello64
** program 'sample/hello64' load. entry point: 0x4000b0, vaddr: 0x4000b0, offset: 0xb0, size: 0x23
sdb> disasm 0x4000b0
      4000b0: b8 04 00 00 00                    mov       eax, 4
      4000b5: bb 01 00 00 00                    mov       ebx, 1
      4000ba: b9 d4 00 60 00                    mov       ecx, 0x6000d4
      4000bf: ba 0e 00 00 00                    mov       edx, 0xe
      4000c4: cd 80                             int       0x80
      4000c6: b8 01 00 00 00                    mov       eax, 1
      4000cb: bb 00 00 00 00                    mov       ebx, 0
      4000d0: cd 80                             int       0x80
      4000d2: c3                                ret
sdb> b 0x4000c6
sdb> l
  0:  4000c6
sdb> run
** pid 11796
hello, world!
** breakpoint @       4000c6: b8 01 00 00 00                    mov       eax, 1
sdb> set rip 0x4000b0
sdb> cont
hello, world!
** breakpoint @       4000c6: b8 01 00 00 00                    mov       eax, 1
sdb> delete 0
** breakpoint 0 deleted.
sdb> set rip 0x4000b0
sdb> cont
hello, world!
** child process 11796 terminated normally (code 0)

License

MIT