Use build id to lookup debug symbols for libc >= 2.31

Cargo.toml

@@ -31,6 +31,8 @@ strfmt = "0.1.6"
 maplit = "1.0.2"
 flate2 = "1.0.22"
 zstd = "0.10.0"
+version-compare = "0.1.0"
+hex = "0.4.3"
 
 [dependencies.reqwest]
 version = "0.11.9"

src/elf/build_id.rs

@@ -0,0 +1,22 @@
+use crate::elf;
+
+use std::path::Path;
+
+use ex::fs;
+use snafu::ResultExt;
+
+/// Get the build id of the given elf file
+pub fn get_build_id(path: &Path) -> elf::parse::Result<String> {
+    let bytes = fs::read(path).context(elf::parse::ReadSnafu)?;
+    let elf = elf::parse(path, &bytes)?;
+
+    let mut iter = elf
+        .iter_note_sections(&bytes, Some(".note.gnu.build-id"))
+        .unwrap();
+    let section = iter
+        .next()
+        .unwrap()
+        .context(elf::parse::GoblinSnafu { path })?;
+
+    Ok(hex::encode(section.desc))
+}

src/elf/mod.rs

@@ -1,6 +1,8 @@
+mod build_id;
 pub mod detect;
 mod has_debug_syms;
 pub mod parse;
 
+pub use build_id::get_build_id;
 pub use has_debug_syms::has_debug_syms;
 pub use parse::parse;

src/fetch_ld.rs

@@ -1,9 +1,11 @@
+use crate::cpu_arch::CpuArch;
 use crate::libc_deb;
 use crate::libc_version::LibcVersion;
 
 use colored::Colorize;
 use snafu::ResultExt;
 use snafu::Snafu;
+use version_compare::Cmp;
 
 #[derive(Debug, Snafu)]
 pub enum Error {
@@ -22,7 +24,18 @@ pub fn fetch_ld(ver: &LibcVersion) -> Result {
     println!("{}", "fetching linker".green().bold());
 
     let deb_file_name = format!("libc6_{}.deb", ver);
-    let ld_name = format!("ld-{}.so", ver.string_short);
-    libc_deb::write_ubuntu_pkg_file(&deb_file_name, &ld_name, &ld_name).context(DebSnafu)?;
+
+    let ld_name = if version_compare::compare_to(&ver.string_short, "2.34", Cmp::Lt).unwrap() {
+        format!("ld-{}.so", ver.string_short)
+    } else {
+        match ver.arch {
+            CpuArch::I386 => "ld-linux.so.2",
+            CpuArch::Amd64 => "ld-linux-x86-64.so.2",
+        }
+        .to_string()
+    };
+    let out_name = format!("ld-{}.so", ver.string_short);
+
+    libc_deb::write_ubuntu_pkg_file(&deb_file_name, &ld_name, &out_name).context(DebSnafu)?;
     Ok(())
 }

src/solvepy.rs

@@ -50,7 +50,7 @@ fn make_bindings(opts: &Opts) -> String {
             &opts.template_bin_name,
             patch_bin::bin_patched_path(opts)
                 .as_ref()
-                .or_else(|| opts.bin.as_ref()),
+                .or(opts.bin.as_ref()),
         ),
         bind_line(&opts.template_libc_name, opts.libc.as_ref()),
         bind_line(&opts.template_ld_name, opts.ld.as_ref()),

src/unstrip_libc.rs

@@ -16,6 +16,7 @@ use ex::io;
 use snafu::ResultExt;
 use snafu::Snafu;
 use tempfile::TempDir;
+use version_compare::Cmp;
 
 #[derive(Debug, Snafu)]
 #[allow(clippy::enum_variant_names)]
@@ -57,7 +58,12 @@ fn do_unstrip_libc(libc: &Path, ver: &LibcVersion) -> Result {
 
     let sym_path = tmp_dir.path().join("libc-syms");
 
-    let name = format!("libc-{}.so", ver.string_short);
+    let name = if version_compare::compare_to(&ver.string_short, "2.23", Cmp::Lt).unwrap() {
+        format!("libc-{}.so", ver.string_short)
+    } else {
+        let build_id = elf::get_build_id(libc).context(ElfParseSnafu)?;
+        build_id.chars().skip(2).collect::<String>() + ".debug"
+    };
 
     libc_deb::write_ubuntu_pkg_file(&deb_file_name, &name, &sym_path).context(DebSnafu)?;