feat: embed wrappers into ELF binaries

Author: m-hilgendorf

packages/std/Cargo.lock

@@ -26,6 +26,7 @@ pedantic = { level = "warn", priority = -1 }
 result_large_err = "allow"
 
 [workspace.dependencies]
+bytes = { version = "1", features = ["serde"] }
 clap = { version = "4", features = ["derive"] }
 fnv = "1"
 futures = "0.3"
@@ -35,6 +36,7 @@ libc = "0.2"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 tangram_client = { default-features = false, git = "https://github.com/tangramdotdev/tangram", rev = "58527c57de3217c82d0c54e3dacaba6394245fec" }
+tangram_serialize = { default-features = false, git = "https://github.com/tangramdotdev/tangram", rev = "58527c57de3217c82d0c54e3dacaba6394245fec" }
 tempfile = "3"
 tokio = { version = "1", default-features = false, features = [
   "rt",
@@ -77,12 +79,16 @@ path = "packages/std/lib.rs"
 workspace = true
 
 [dependencies]
+bytes = { workspace = true }
 futures = { workspace = true }
 serde = { workspace = true }
 serde_json = { workspace = true }
 tangram_client = { workspace = true }
+tangram_serialize = { workspace = true }
+tempfile = { workspace = true }
 tracing = { workspace = true, optional = true }
 tracing-subscriber = { workspace = true, optional = true }
 
 [features]
 tracing = ["dep:tracing", "dep:tracing-subscriber"]
+default = ["tracing"]

packages/std/Cargo.toml

@@ -23,10 +23,12 @@ export const source = () => {
 
 export type Arg = {
 	host?: string;
+	embedWrapper?: boolean | undefined;
 };
 
 export const build = async (arg?: Arg) => {
 	const host = arg?.host ?? (await std.triple.host());
+	const embedWrapper = arg?.embedWrapper ?? true;
 
 	const configure = {
 		args: ["--disable-dependency-tracking"],
@@ -48,7 +50,14 @@ export const build = async (arg?: Arg) => {
 		install,
 	};
 
-	const env = std.env.arg(sdk(host), { utils: false });
+	let envArgs: Array<tg.Unresolved<std.env.Arg>> = [
+		sdk(host),
+		{ utils: false },
+	];
+	if (embedWrapper) {
+		envArgs.push({ TANGRAM_LINKER_EMBED_WRAPPER: true });
+	}
+	const env = std.env.arg(...envArgs);
 
 	const output = await autotoolsInternal({
 		bootstrap: true,

packages/std/a.out

@@ -0,0 +1,58 @@
+#include <elf.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <sys/mman.h>
+
+#define eprintf(...) fprintf(stderr, __VA_ARGS__)
+
+int main(int argc, const char** argv) {
+   	if (argc != 3) {
+		return 111;
+	}
+	const char* input = argv[0];
+	const char* output = argv[1];
+	int status = 0;
+
+	int in  = open(input, O_RDONLY);
+	int out = open(output, O_RDWR | O_CREAT, 0o755);
+	if (in < 0 || out < 0) {
+		perror("failed to open in/out/files");
+		return 1;
+	}
+	off_t size = lseek(in, 0, SEEK_END);
+	if (size < 0) {
+		perror("failed to seek to the end of the input");
+		status = 1;
+		goto cleanup;
+	}
+
+	uint8_t* elf = (uint8_t*)mmap(
+		NULL,
+		(size_t)size,
+		PROT_READ,
+		MAP_ANONYMOUS | MAP_PRIVATE,
+		in,
+		0
+	);
+
+	Elf64_Ehdr* ehdr = (Elf64_Ehdr*)elf;
+	Elf64_Phdr* phdr = (Elf64_Phr*)(elf + ehdr->e_phoff);
+
+	bool copied = false
+	for (int i = 0; i < ehdr->e_phnum) {
+		if (phdr[i].p_type != PT_LOAD) {
+			continue;
+		}
+		if (copied) {
+			status = 1;
+			eprintf("expected a single loadable segment");
+			goto cleanup;
+		}
+
+	}
+cleanup:
+	munmap(elf, size);
+	close(in);
+	close(out);
+	return status;
+}

packages/std/bootstrap/make.tg.ts

@@ -0,0 +1,7 @@
+SECTIONS
+{
+    . = 0x0;
+    .text : {
+        *(.text.start)
+     }
+}