From cd8ae69d7ff434b1d06fbf327d3d9b9f0059eba6 Mon Sep 17 00:00:00 2001
From: Elnath <elnathbeta@gmail.com>
Date: Fri, 18 Apr 2025 19:27:55 +0200
Subject: [PATCH] Changing a register value

---
 src/main.rs | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 8baa1d7..2a9061f 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,10 +1,10 @@
 mod child;
 
+use nix::libc::user_regs_struct;
 use nix::sys::ptrace::*;
 use nix::sys::wait::waitpid;
-use nix::unistd::{ForkResult, fork};
+use nix::unistd::{fork, ForkResult};
 use std::ffi::CString;
-use std::io;
 use std::process::ExitCode;
 
 fn main() -> ExitCode {
@@ -38,8 +38,17 @@ fn main() -> ExitCode {
                         },
                         Stopped(_pid, _signal) => {
                             let regs = getregs(child_pid).unwrap();
-                            println!("🔎 [{}] rip= 0x{:016X}, rax = 0x{rax:X} ({rax})", before_instruction, regs.rip, rax = regs.rax);
-                            io::stdin().read_line(&mut String::new()).unwrap();
+                            println!(
+                                "🔎 [{}] rip= 0x{:016X}, rax = 0x{rax:X} ({rax})",
+                                before_instruction,
+                                regs.rip,
+                                rax = regs.rax
+                            );
+                            if regs.rax == 60 {
+                                println!("Let's change a register!");
+                                let new_regs = user_regs_struct { rdi: 54, ..regs };
+                                setregs(child_pid, new_regs).unwrap();
+                            }
                             before_instruction += 1;
                             step(child_pid, None).unwrap();
                         }