Upgrade to rustc 1.30-nightly (2018-08-30)

.cargo/config.toml

@@ -0,0 +1,3 @@
+[build]
+rustflags = ["-C", "relocation-model=static"]
+incremental = false

.cirrus.yml

@@ -0,0 +1,20 @@
+task:
+  name: Linux amd64 nightly
+  container:
+    image: rustlang/rust:nightly
+    cpu: 1
+    memory: 1
+  cargo_cache:
+    folder: $HOME/.cargo/registry
+    fingerprint_script: cat Cargo.lock 2> /dev/null || true
+  setup_script:
+    - apt-get update
+    - apt-get install -yqq nasm bsdmainutils
+  build_script:
+    - ./build.sh
+  test_script:
+    - ./tinyrust
+    - test "$(./tinyrust)" == 'Hello!'
+    - test "$(wc -c < tinyrust)" -eq 137
+  before_cache_script:
+    - rm -rf $HOME/.cargo/registry/index

.gitignore

@@ -1,7 +1,16 @@
+# cargo
+/target
+
+# pre-cargo
 /syscall.rs
+/libtinyrust.rlib
+
+# rlib extraction and other intermediate artefacts
+/*.o
+/*.rmeta
 /payload
 /payload.bin
-/tinyrust
 /tinyrust.ll
-/tinyrust.o
-/libtinyrust.rlib
+
+# final executable
+/tinyrust

Cargo.toml

@@ -0,0 +1,30 @@
+[package]
+name = "tiny-rust-executable"
+version = "0.5.1"
+authors = [
+    "Keegan McAllister <mcallister.keegan@gmail.com>",
+    "Melvin Kicchi <melvin@likes.pounc.es>",
+    "Hiroki Noda <kubo39@gmail.com>",
+    "Torbjørn Birch Moltu <t.b.moltu@lyse.net>"
+]
+license = "Apache-2.0 OR MIT"
+edition = "2015"
+
+[lib]
+name = "tinyrust"
+path = "tinyrust.rs"
+
+[profile.dev]
+opt-level = "z"
+overflow-checks = false
+lto = false
+panic = "abort"
+
+[profile.release]
+opt-level = "z"
+overflow-checks = false
+lto = false # enabling LTO breaks objdump and requires other flags to ld
+panic = "abort"
+
+[dependencies]
+sc = "0.2.3"

LICENSE-MIT

@@ -1,5 +1,3 @@
-Copyright (c) 2014 The syscall.rs Project Developers
-
 Permission is hereby granted, free of charge, to any
 person obtaining a copy of this software and associated
 documentation files (the "Software"), to deal in the

README.md

@@ -1,61 +1,98 @@
-# Using Rust to make a 151-byte static AMD64 Linux binary
+# Using Rust to make a 137-byte static AMD64 Linux binary
 
-`elf.s` contains a custom ELF header, but no instructions.  All of the machine
-code comes out of `rustc`.  (Although all of the instructions that survive
-optimization *went in* as inline assembly.)
+[![Build Status](https://api.cirrus-ci.com/github/tormol/tiny-rust-executable.svg)](https://cirrus-ci.com/github/tormol/tiny-rust-executable)
 
-```
-$ ./build.sh
-Tested on rustc 1.0.0-dev (44a287e6e 2015-01-08 17:03:40 -0800)
-You have  rustc 1.0.0-dev (44a287e6e 2015-01-08 17:03:40 -0800)
+`elf.s` contains a custom ELF header, but no instructions.
+All of the machine code comes out of `rustc`.
+(While most of the operations originate from inline assembly, LLVM replaces the instructions with more compact ones!)
 
-Cloning into 'syscall.rs'...
-   Compiling syscall v0.1.0 (file:///home/keegan/tiny-rust-demo/syscall.rs)
+This project is built by running the `./build.sh` script instead of `cargo build`: Making the binary this small requires post-processing steps which cargo doesn't support.  
+Requires nightly Rust because it uses inline assembly (through the `sc` crate) to make direct system calls.
 
-+ rustc tinyrust.rs -O -C no-stack-check -C relocation-model=static -L syscall.rs/target
-+ ar x libtinyrust.rlib tinyrust.o
-+ objdump -dr tinyrust.o
+[Blog post about this demo](http://mainisusuallyafunction.blogspot.com/2015/01/151-byte-static-linux-binary-in-rust.html), by Keegan McAllister who originally created it.
 
-tinyrust.o:     file format elf64-x86-64
+## Example
+
+```sh
+$ ./build.sh
+Tested on rustc 1.85.0 (4d91de4e4 2025-02-17)
+You have  rustc 1.85.0 (4d91de4e4 2025-02-17)
+
++ cargo build --release --verbose
+    Updating crates.io index
+     Locking 1 package to latest compatible version
+  Downloaded sc v0.2.7
+  Downloaded 1 crate (39.6KiB) in 0.88s
+   Compiling sc v0.2.7
+     Running `/home/tbm/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/rustc --crate-name sc --edition=2015 /home/tbm/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/sc-0.2.7/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=137 --crate-type lib --emit=dep-info,metadata,link -C opt-level=z -C panic=abort -C embed-bitcode=no --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values())' -C metadata=de0ba5d176876c9c -C extra-filename=-e50ec66b37f4e2cb --out-dir /home/tbm/p/rust/tiny-rust-demo/target/release/deps -C strip=debuginfo -L dependency=/home/tbm/p/rust/tiny-rust-demo/target/release/deps --cap-lints allow -C relocation-model=static`
+   Compiling tiny-rust-executable v0.5.1 (/home/tbm/p/rust/tiny-rust-demo)
+     Running `/home/tbm/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/rustc --crate-name tinyrust --edition=2015 tinyrust.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=137 --crate-type lib --emit=dep-info,metadata,link -C opt-level=z -C panic=abort -C embed-bitcode=no --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values())' -C metadata=76aa331090f20463 -C extra-filename=-f769982e789cd78c --out-dir /home/tbm/p/rust/tiny-rust-demo/target/release/deps -C strip=debuginfo -L dependency=/home/tbm/p/rust/tiny-rust-demo/target/release/deps --extern sc=/home/tbm/p/rust/tiny-rust-demo/target/release/deps/libsc-e50ec66b37f4e2cb.rmeta -C relocation-model=static`
+    Finished `release` profile [optimized] target(s) in 0.06s
+++ ar t target/release/libtinyrust.rlib
+++ grep '.o$'
++ OBJECT=tinyrust-f769982e789cd78c.tinyrust.35d04aaf99cb8b97-cgu.0.rcgu.o
++ ar x target/release/libtinyrust.rlib tinyrust-f769982e789cd78c.tinyrust.35d04aaf99cb8b97-cgu.0.rcgu.o
++ objdump -dr tinyrust-f769982e789cd78c.tinyrust.35d04aaf99cb8b97-cgu.0.rcgu.o
+
+tinyrust-f769982e789cd78c.tinyrust.35d04aaf99cb8b97-cgu.0.rcgu.o:     file format elf64-x86-64
 
 
 Disassembly of section .text.main:
 
 0000000000000000 <main>:
-   0:	b8 01 00 00 00       	mov    $0x1,%eax
-   5:	bf 01 00 00 00       	mov    $0x1,%edi
-   a:	be 08 00 40 00       	mov    $0x400008,%esi
-   f:	ba 07 00 00 00       	mov    $0x7,%edx
-  14:	0f 05                	syscall
-  16:	b8 3c 00 00 00       	mov    $0x3c,%eax
-  1b:	31 ff                	xor    %edi,%edi
-  1d:	0f 05                	syscall
+   0:   6a 01                   push   $0x1
+   2:   58                      pop    %rax
+   3:   6a 07                   push   $0x7
+   5:   5a                      pop    %rdx
+   6:   be 08 00 40 00          mov    $0x400008,%esi
+   b:   48 89 c7                mov    %rax,%rdi
+   e:   0f 05                   syscall
+  10:   6a 3c                   push   $0x3c
+  12:   58                      pop    %rax
+  13:   31 ff                   xor    %edi,%edi
+  15:   0f 05                   syscall
+  17:   0f 0b                   ud2
 + echo
 
-+ ld --gc-sections -e main -T script.ld -o payload tinyrust.o
++ ld --gc-sections -e main -T script.ld -o payload tinyrust-f769982e789cd78c.tinyrust.35d04aaf99cb8b97-cgu.0.rcgu.o
 + objcopy -j combined -O binary payload payload.bin
-++ nm -f posix payload
+++ nm --format=posix payload
 ++ grep '^main '
 ++ awk '{print $3}'
-+ ENTRY=0000000000400078
-+ set -x
-+ nasm -f bin -o tinyrust -D entry=0x0000000000400078 elf.s
++ ENTRY=400070
++ nasm -f bin -o tinyrust -D entry=0x400070 elf.s
 + chmod +x tinyrust
-+ hd tinyrust
-00000000  7f 45 4c 46 02 01 01 00  48 65 6c 6c 6f 21 0a 00  |.ELF....Hello!..|
-00000010  02 00 3e 00 01 00 00 00  78 00 40 00 00 00 00 00  |..>.....x.@.....|
-00000020  40 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |@...............|
-00000030  00 00 00 00 40 00 38 00  01 00 00 00 00 00 00 00  |....@.8.........|
-00000040  01 00 00 00 07 00 00 00  00 00 00 00 00 00 00 00  |................|
-00000050  00 00 40 00 00 00 00 00  00 00 40 00 00 00 00 00  |..@.......@.....|
-00000060  97 00 00 00 00 00 00 00  97 00 00 00 00 00 00 00  |................|
-00000070  00 10 00 00 00 00 00 00  b8 01 00 00 00 bf 01 00  |................|
-00000080  00 00 be 08 00 40 00 ba  07 00 00 00 0f 05 b8 3c  |.....@.........<|
-00000090  00 00 00 31 ff 0f 05                              |...1...|
-00000097
++ hexdump -C tinyrust
+00000000  7f 45 4c 46 02 01 01 09  48 65 6c 6c 6f 21 0a 00  |.ELF....Hello!..|
+00000010  02 00 3e 00 01 00 00 00  70 00 40 00 00 00 00 00  |..>.....p.@.....|
+00000020  38 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |8...............|
+00000030  00 00 00 00 38 00 38 00  01 00 00 00 07 00 00 00  |....8.8.........|
+00000040  00 00 00 00 00 00 00 00  00 00 40 00 00 00 00 00  |..........@.....|
+00000050  00 00 40 00 00 00 00 00  89 00 00 00 00 00 00 00  |..@.............|
+00000060  89 00 00 00 00 00 00 00  00 10 00 00 00 00 00 00  |................|
+00000070  6a 01 58 6a 07 5a be 08  00 40 00 48 89 c7 0f 05  |j.Xj.Z...@.H....|
+00000080  6a 3c 58 31 ff 0f 05 0f  0b                       |j<X1.....|
+00000089
 + wc -c tinyrust
-151 tinyrust
+137 tinyrust
 
 $ ./tinyrust
 Hello!
 ```
+
+## License
+
+Licensed under either of
+
+* Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
+* MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
+
+at your option.
+
+### Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.
+
+## See Also
+
+* [A 99-byte x86 (32-bit) Go executable](https://github.com/xaionaro-go/tinyhelloworld)

build.sh

@@ -1,38 +1,32 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 set -e
 
-for d in rustc git cargo ar ld objcopy nasm; do
+for d in rustc cargo ar ld objcopy nasm hexdump; do
     which $d >/dev/null || (echo "Can't find $d, needed to build"; exit 1)
 done
 
-printf "Tested on rustc 1.1.0-dev (435622028 2015-05-04)\nYou have  "
+printf "Tested on rustc 1.85.0 (4d91de4e4 2025-02-17)\nYou have  "
 rustc --version
 echo
 
-if [ ! -d syscall.rs ]; then
-    git clone https://github.com/kmcallister/syscall.rs
-    (cd syscall.rs && cargo build --release)
-    echo
-fi
-
 set -x
 
-rustc tinyrust.rs \
-    -O -C no-stack-check -C relocation-model=static \
-    -L syscall.rs/target/release
+cargo build --release --verbose
 
-ar x libtinyrust.rlib tinyrust.o
+# tinyrust.tinyrust.3a1fbbbh-cgu.0.rcgu.o
+OBJECT=$(ar t target/release/libtinyrust.rlib | grep '.o$')
+ar x target/release/libtinyrust.rlib "$OBJECT"
 
-objdump -dr tinyrust.o
+objdump -dr "$OBJECT"
 echo
 
-ld --gc-sections -e main -T script.ld -o payload tinyrust.o
+ld --gc-sections -e main -T script.ld -o payload "$OBJECT"
 objcopy -j combined -O binary payload payload.bin
 
-ENTRY=$(nm -f posix payload | grep '^main ' | awk '{print $3}')
+ENTRY=$(nm --format=posix payload | grep '^main ' | awk '{print $3}')
 nasm -f bin -o tinyrust -D entry=0x$ENTRY elf.s
 
 chmod +x tinyrust
-hd tinyrust
+hexdump -C tinyrust
 wc -c tinyrust

elf.s

@@ -6,7 +6,7 @@
 
 ehdr:
     db  0x7f, "ELF"  ; magic
-    db  2, 1, 1, 0   ; 64-bits, little endian, version 1
+    db  2, 1, 1, 9   ; 64-bits, little endian, version 9(FreeBSD, linux loader ignores this)
 
     ; This padding is a perfect place to put a string constant!
     db "Hello!", 0x0A, 0
@@ -20,13 +20,11 @@ ehdr:
     dd  0            ; e_flags
     dw  ehdrsize     ; e_ehsize
     dw  phdrsize     ; e_phentsize
-    dw  1            ; e_phnum
-    dw  0, 0, 0      ; e_sh*
 
 ehdrsize  equ  $ - ehdr
 
 phdr:
-    dd  1            ; p_type = loadable program segment
+    dd  1            ; p_type = loadable program segment & (e_phnum + e_sh*)
     dd  7            ; p_flags = rwx
     dq  0            ; p_offset
     dq  $$, $$       ; p_vaddr, p_paddr

script.ld

@@ -1,7 +1,7 @@
 SECTIONS {
-    . = 0x400078;
+    . = 0x400070;
 
-    combined . : AT(0x400078) ALIGN(1) SUBALIGN(1) {
+    combined . : AT(0x400070) ALIGN(1) SUBALIGN(1) {
         *(.text*)
         *(.data*)
         *(.rodata*)

tinyrust.rs

@@ -1,14 +1,13 @@
-#![crate_type="rlib"]
-#![feature(core)]
+#![no_std]
 
-#[macro_use] extern crate syscall;
+#[macro_use] extern crate sc;
 
-use std::{mem, raw, intrinsics};
+use core::{hint,slice};
 
 fn exit(n: usize) -> ! {
     unsafe {
         syscall!(EXIT, n);
-        intrinsics::unreachable()
+        hint::unreachable_unchecked()
     }
 }
 
@@ -22,12 +21,7 @@ fn write(fd: usize, buf: &[u8]) {
 pub fn main() {
     // Make a Rust value representing the string constant we stashed
     // in the ELF file header.
-    let message: &'static [u8] = unsafe {
-        mem::transmute(raw::Slice {
-            data: 0x00400008 as *const u8,
-            len: 7,
-        })
-    };
+    let message = unsafe{ slice::from_raw_parts(0x00400008 as *const u8, 7) };
 
     write(1, message);
     exit(0);