Don't require objdump

Cargo.toml

@@ -10,11 +10,12 @@ repository = "https://github.com/trailofbits/anchor-coverage"
 [dependencies]
 addr2line = "0.24"
 anyhow = "1.0"
-assert_cmd = "2.0"
 byteorder = "1.5"
 cargo_metadata = "0.19"
 
 [dev-dependencies]
+assert_cmd = "2.0"
+ctor = "0.4"
 lcov = "0.8"
 regex = "1.11"
 tempfile = "3.19"

src/bin/anchor-coverage.rs

@@ -1,9 +1,8 @@
 use anyhow::{Result, bail, ensure};
 use std::{
     env::{args, current_dir},
-    ffi::OsStr,
-    fs::{create_dir_all, read_dir, remove_dir_all},
-    path::{Path, PathBuf},
+    fs::{create_dir_all, remove_dir_all},
+    path::Path,
     process::Command,
 };
 
@@ -45,7 +44,7 @@ Usage: {0} [ANCHOR_TEST_ARGS]...
 
     anchor_test(&options.args, &sbf_trace_dir)?;
 
-    let pcs_paths = collect_pcs_paths(&sbf_trace_dir)?;
+    let pcs_paths = anchor_coverage::util::files_with_extension(&sbf_trace_dir, "pcs")?;
 
     if pcs_paths.is_empty() {
         bail!(
@@ -94,15 +93,3 @@ fn anchor_test(args: &[String], sbf_trace_dir: &Path) -> Result<()> {
     ensure!(status.success(), "command failed: {:?}", command);
     Ok(())
 }
-
-fn collect_pcs_paths(path: &Path) -> Result<Vec<PathBuf>> {
-    let mut pcs_paths = Vec::new();
-    for result in read_dir(path)? {
-        let entry = result?;
-        let path = entry.path();
-        if entry.path().extension() == Some(OsStr::new("pcs")) {
-            pcs_paths.push(path);
-        }
-    }
-    Ok(pcs_paths)
-}

src/lib.rs

@@ -16,7 +16,7 @@ use insn::Insn;
 mod start_address;
 use start_address::start_address;
 
-mod util;
+pub mod util;
 use util::{StripCurrentDir, files_with_extension};
 
 mod vaddr;

src/start_address.rs

@@ -1,39 +1,35 @@
-//! A hack to get an ELF's start address by calling `objdump` on the command line.
-//!
-//! A proper solution would use [`gimli`] or something similar.
-//!
-//! [`gimli`]: https://crates.io/crates/gimli
+//! Gets an ELF's start address by reading its `Elf64Hdr`.
 
-use anyhow::{Result, bail, ensure};
-use assert_cmd::output::OutputError;
-use std::{path::Path, process::Command};
+use anyhow::Result;
+use std::{fs::File, io::Read, path::Path, slice::from_raw_parts_mut};
+
+const EI_NIDENT: usize = 16;
+
+#[allow(clippy::struct_field_names)]
+#[derive(Default)]
+#[repr(C)]
+pub struct Elf64Hdr {
+    pub e_ident: [u8; EI_NIDENT],
+    pub e_type: u16,
+    pub e_machine: u16,
+    pub e_version: u32,
+    pub e_entry: u64,
+    pub e_phoff: u64,
+    pub e_shoff: u64,
+    pub e_flags: u32,
+    pub e_ehsize: u16,
+    pub e_phentsize: u16,
+    pub e_phnum: u16,
+    pub e_shentsize: u16,
+    pub e_shnum: u16,
+    pub e_shstrndx: u16,
+}
 
 pub fn start_address(path: impl AsRef<Path>) -> Result<u64> {
-    let mut command = Command::new("objdump");
-    command.arg("-f");
-    command.arg(path.as_ref());
-    let output = command.output()?;
-    ensure!(
-        output.status.success(),
-        "command failed `{command:?}`: {}",
-        OutputError::new(output)
-    );
-    let stdout = std::str::from_utf8(&output.stdout)?;
-    for line in stdout.lines() {
-        // smoelius: "start address" may (LLVM `objdump`) or may not (GNU `objdump`) be followed by
-        // a colon (':'). Hence, we cannot simply use `strip_prefix`.
-        if !line.starts_with("start address") {
-            continue;
-        }
-        let Some(position) = line.rfind("0x") else {
-            continue;
-        };
-        if let Ok(address) = u64::from_str_radix(&line[position + 2..], 16) {
-            return Ok(address);
-        }
-    }
-    bail!(
-        "failed to determine start address for `{}`",
-        path.as_ref().display()
-    );
+    let mut file = File::open(path)?;
+    let mut elf64_hdr = Elf64Hdr::default();
+    let buf: &mut [u8] =
+        unsafe { from_raw_parts_mut((&raw mut elf64_hdr).cast::<u8>(), size_of::<Elf64Hdr>()) };
+    file.read_exact(buf)?;
+    Ok(elf64_hdr.e_entry)
 }

tests/ci.rs

@@ -1,6 +1,13 @@
 use assert_cmd::Command;
 use regex::Regex;
-use std::{fs::read_to_string, path::Path};
+use std::{env::remove_var, fs::read_to_string, path::Path};
+
+#[ctor::ctor]
+fn initialize() {
+    unsafe {
+        remove_var("CARGO_TERM_COLOR");
+    }
+}
 
 #[test]
 fn clippy() {