Update brioche-packed-userland-exec to use #![no_main]

This skips some Rust runtime setup code and further reduces the binary size
brioche-dev · Dec 31, 2023 · ffac788 · ffac788
1 parent 7e7f8d8
commit ffac788
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Showing 3 changed files with 9 additions and 7 deletions.
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/crates/brioche-packed-userland-exec/Cargo.toml b/crates/brioche-packed-userland-exec/Cargo.toml
@@ -7,5 +7,6 @@ edition = "2021"
 bincode = "2.0.0-rc.3"
 brioche-pack = { path = "../brioche-pack", default-features = false }
 bstr = "1.8.0"
+libc = "0.2.151"
 thiserror = "1.0.51"
 userland-execve = { git = "https://github.com/brioche-dev/userland-execve-rust.git" }
diff --git a/crates/brioche-packed-userland-exec/src/main.rs b/crates/brioche-packed-userland-exec/src/main.rs
@@ -1,19 +1,19 @@
-use std::{
-    ffi::{CStr, CString},
-    process::ExitCode,
-};
+#![no_main]
+
+use std::ffi::{CStr, CString};
 
 use bstr::ByteSlice as _;
 
 const BRIOCHE_PACKED_ERROR: u8 = 121;
 
-fn main() -> ExitCode {
+#[no_mangle]
+pub extern "C" fn main(_argc: libc::c_int, _argv: *const *const libc::c_char) -> libc::c_int {
     let result = run();
     match result {
-        Ok(()) => ExitCode::SUCCESS,
+        Ok(()) => 0,
         Err(err) => {
             eprintln!("brioche-packed error: {err}");
-            ExitCode::from(BRIOCHE_PACKED_ERROR)
+            BRIOCHE_PACKED_ERROR.into()
         }
     }
 }