Executing a target assembly program with execv

Cargo.lock

@@ -5,3 +5,42 @@ version = 4
 [[package]]
 name = "bdb"
 version = "0.0.0"
+dependencies = [
+ "nix",
+]
+
+[[package]]
+name = "bitflags"
+version = "2.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c8214115b7bf84099f1309324e63141d4c5d7cc26862f97a0a857dbefe165bd"
+
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[package]]
+name = "cfg_aliases"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "613afe47fcd5fac7ccf1db93babcb082c5994d996f20b8b159f2ad1658eb5724"
+
+[[package]]
+name = "libc"
+version = "0.2.172"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d750af042f7ef4f724306de029d18836c26c1765a54a6a3f094cbd23a7267ffa"
+
+[[package]]
+name = "nix"
+version = "0.29.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "71e2746dc3a24dd78b3cfcb7be93368c6de9963d30f43a6a73998a9cf4b17b46"
+dependencies = [
+ "bitflags",
+ "cfg-if",
+ "cfg_aliases",
+ "libc",
+]

Cargo.toml

@@ -5,3 +5,4 @@ edition = "2024"
 publish = false
 
 [dependencies]
+nix = { version = "0.29.0", features = ["process", "ptrace"] }

build.rs

@@ -0,0 +1,14 @@
+use std::process::Command;
+
+fn main() {
+    let test_prog_exe_path = &format!("{}/prog", std::env::var("OUT_DIR").unwrap());
+    let test_prog_obj_path = &format!("{}.o", test_prog_exe_path);
+    Command::new("nasm")
+        .args(&["-f", "elf64", "src/prog.nasm", "-o", test_prog_obj_path])
+        .spawn().expect("nasm build failed");
+    Command::new("ld")
+        .args(&[test_prog_obj_path, "-o", test_prog_exe_path])
+        .spawn().expect("linking failed");
+    println!("cargo:rerun-if-changed=src/prog.nasm");
+    println!("cargo:rustc-env=TEST_PROG_PATH={}", test_prog_exe_path);
+}

src/main.rs

@@ -1,3 +1,9 @@
+use nix::unistd::execv;
+use std::ffi::CString;
+
 fn main() {
-    println!("Hello, world!");
+    println!("I am executing {}!", env!("TEST_PROG_PATH"));
+
+    let path = CString::new(env!("TEST_PROG_PATH")).unwrap();
+    execv(&path, &[&path]).unwrap();
 }

src/prog.nasm

@@ -0,0 +1,16 @@
+global _start
+section .text
+_start:
+	mov rax,1
+	mov rdi, 1
+	mov rsi, msg
+	mov rdx, msglen
+	syscall
+
+	mov rdi,0
+	mov rax,60
+	syscall
+
+section .data
+	msg: db `Hello world\n`
+	msglen equ $-msg