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+---
+title: 'Fast x86 Debugging: Using GDB On Apple Silicon with Rosetta emulation'
+date: "12-04-2023"
+---
+# Using GDB On Apple Silicon with Rosetta emulation
+
+This blog post will outline how to setup x86 GDB on M1. This isn't your run-of-the mill x86 emulation -
+this is *FAST* -- using the Rosetta translation engine, instead of QEMU. Thanks to [sporks.space](https://sporks.space/2023/04/12/debugging-an-x86-application-in-rosetta-for-linux/) for the initial writeup of the `ROSETTA_DEBUGSERVER` feature!
+
+![](./demo_gdb.mp4)
+
+
+## System Requirements
+
+I am running on a M1 Chip, running MacOS Sonoma 14.0 (Build 23A339). I have had issues with Rosetta crashing on previous versions of MacOS, so I would reccomend using a later, more stable version (and still occasionally have stability issues).
+
+![](./uname.png)
+
+## UTM / VM Setup
+
+Download a ARMv8 / aarch64 iso like Ubuntu Desktop 22.04.3 LTS. This can be downloaded [here](https://cdimage.ubuntu.com/jammy/daily-live/current/).
+
+Download the UTM DMG from their [Github Releases](https://github.com/utmapp/UTM/releases). At the time of writing, this is UTM 4.4.4. If you run into issues, I would reccomend using `8GB` RAM.
+
+Then, setup your UTM VM.
+
+First, create a New UTM VM.
+![](./step00.png)
+
+Then, select Virtualize.
+![](./step01.png)
+
+Then, select Linux.
+![](./step02.png)
+
+Then, turn on Apple Virtualization, Enable Rosetta, and select your arm64 iso.
+![](./step03.png)
+
+Follow the rest of the steps, changing your disk and RAM as you see fit.
+![](./step04.png)
+
+Then, boot up into Ubuntu server. Skip/continue past all prompts that require the internet, as it will not have internet access. Additionally, check 'Install OpenSSH server'.
+![](./step05.png)
+
+After you finish and reboot, go back to UTM and remove the ISO Drive so you can boot up into Ubuntu.
+![](./step06.png)
+
+## Enabling Network Access
+
+Edit the network configuration so that you can access the internet.
+
+```bash
+sudo vim /etc/netplan/00-installer-config.yaml
+```
+
+to the following contents (your network interface may be slightly different):
+
+```yaml
+network:
+  ethernets:
+    enp0s1:
+      dhcp4: true
+      nameservers:
+        addresses: [8.8.8.8, 1.1.1.1]
+  version: 2
+```
+
+and finally, we can download ifconfig and quickly check our host IP.
+
+```bash
+sudo netplan apply
+sudo apt update && sudo apt install net-tools
+ifconfig
+```
+
+## Setting up Ubuntu
+
+You should now be able to ssh into your VM from your host with
+
+```bash
+ssh <user>@<ip>
+```
+
+And then once connected, upgrade your system and add amd64 (x86) package repositories.
+
+```bash
+sudo apt upgrade
+dpkg --add-architecture 'amd64'
+sudo apt install gdb-multiarch
+sudo apt install libc:amd64
+sudo apt install gcc:amd64
+```
+
+
+## Rosetta Passthrough
+
+Then follow the steps to register Rosetta passthrough (well described in the [UTM Docs](https://docs.getutm.app/advanced/rosetta/))
+
+```bash
+sudo mkdir /media/rosetta
+sudo mount -t virtiofs rosetta /media/rosetta
+sudo echo 'rosetta\t/media/rosetta\tvirtiofs\tro,nofail\t0\t0' >> /etc/fstab
+sudo /usr/sbin/update-binfmts --install rosetta /media/rosetta/rosetta \
+     --magic "\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x3e\x00" \
+     --mask "\xff\xff\xff\xff\xff\xfe\xfe\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff" \
+     --credentials yes --preserve no --fix-binary yes
+```
+
+## Your First Test
+
+You can ensure everything is working by writing a simple `main.c` binary:
+
+```c
+#include <stdio.h>
+
+int main() {
+  puts("Hello x86!");
+}
+```
+
+and compiling/running it
+
+```bash
+gcc main.c -o main && ./main
+```
+
+## Using GDB
+
+First, make sure that ptrace trap is enabled. The reason we need to do this is explained [here](https://stackoverflow.com/a/77480313/8761914).
+
+```
+sudo sh << END
+echo 0 > /proc/sys/kernel/yama/ptrace_scope
+END
+```
+
+Finally, we can use GDB! In one terminal, run the target program with
+
+```bash
+ROSETTA_DEBUGSERVER_PORT=1234 ./program
+```
+
+and in a seperate terminal,
+
+```
+gdb
+$ set architecture i386:x86-64
+$ file ./program
+$ target remote localhost:1234
+```