link musl libc statically

In the context of musl, users are typically expecting statically-linked tools,
as this is one of musl's strong suits and one of the biggest reasons to use it
instead of glibc (that is not static-link-friendly for reasons).

- remove the build-flag which was causing musl libc to be linked dynamically
- re-add which feat_os_unix_musl which was removed in 21d5cef
- exclude stdbuf from feat_os_unix_musl, since libstdbuf.so can't be built with a statically linked musl libc
- add test_musl_no_dynamic_deps so that this does not regress in the future

Fixes #8572

Signed-off-by: Etienne Cordonnier <[email protected]>

Author: Ecordonnier

.cargo/config.toml

@@ -8,8 +8,3 @@ linker = "x86_64-unknown-redox-gcc"
 [env]
 # See feat_external_libstdbuf in src/uu/stdbuf/Cargo.toml
 LIBSTDBUF_DIR = "/usr/local/libexec/coreutils"
-
-# libstdbuf must be a shared library, so musl libc can't be linked statically
-# https://github.com/rust-lang/rust/issues/82193
-[build]
-rustflags = ["-C", "target-feature=-crt-static"]

.github/workflows/CICD.yml

@@ -531,13 +531,13 @@ jobs:
           # - { os , target , cargo-options , default-features,  features , use-cross , toolchain, skip-tests, workspace-tests, skip-package, skip-publish }
           - { os: ubuntu-latest  , target: arm-unknown-linux-gnueabihf , features: feat_os_unix_gnueabihf , use-cross: use-cross , skip-tests: true }
           - { os: ubuntu-24.04-arm  , target: aarch64-unknown-linux-gnu   , features: feat_os_unix_gnueabihf }
-          - { os: ubuntu-latest  , target: aarch64-unknown-linux-musl  , features: feat_os_unix      , use-cross: use-cross , skip-tests: true }
+          - { os: ubuntu-latest  , target: aarch64-unknown-linux-musl  , features: feat_os_unix_musl , use-cross: use-cross , skip-tests: true }
           # - { os: ubuntu-latest  , target: x86_64-unknown-linux-gnu    , features: feat_selinux           , use-cross: use-cross }
           - { os: ubuntu-latest  , target: i686-unknown-linux-gnu      , features: "feat_os_unix,test_risky_names", use-cross: use-cross }
-          - { os: ubuntu-latest  , target: i686-unknown-linux-musl     , features: feat_os_unix      , use-cross: use-cross }
+          - { os: ubuntu-latest  , target: i686-unknown-linux-musl     , features: feat_os_unix_musl , use-cross: use-cross }
           - { os: ubuntu-latest  , target: x86_64-unknown-linux-gnu    , features: "feat_os_unix,test_risky_names", use-cross: use-cross }
           - { os: ubuntu-latest  , target: x86_64-unknown-linux-gnu    , features: "feat_os_unix,uudoc"   , use-cross: no, workspace-tests: true }
-          - { os: ubuntu-latest  , target: x86_64-unknown-linux-musl   , features: feat_os_unix      , use-cross: use-cross }
+          - { os: ubuntu-latest  , target: x86_64-unknown-linux-musl   , features: feat_os_unix_musl , use-cross: use-cross }
           - { os: ubuntu-latest  , target: x86_64-unknown-redox        , features: feat_os_unix_redox     , use-cross: redoxer , skip-tests: true }
           - { os: ubuntu-latest  , target: wasm32-unknown-unknown      , default-features: false, features: uucore/format, skip-tests: true, skip-package: true, skip-publish: true }
           - { os: macos-latest   , target: aarch64-apple-darwin        , features: feat_os_macos, workspace-tests: true } # M1 CPU

Cargo.toml

@@ -163,14 +163,22 @@ feat_os_macos = [
   "feat_require_unix_hostid",
 ]
 # "feat_os_unix" == set of utilities which can be built/run on modern/usual *nix platforms.
-# Also used for targets binding to the "musl" library (ref: <https://musl.libc.org/about.html>)
 feat_os_unix = [
   "feat_Tier1",
   #
   "feat_require_unix",
   "feat_require_unix_hostid",
   "feat_require_unix_utmpx",
 ]
+# "feat_os_unix_musl" == set of utilities which can be built/run on targets binding to the "musl" library (ref: <https://musl.libc.org/about.html>)
+# It excludes stdbuf due to cdylib limitations (https://github.com/rust-lang/rust/issues/82193)
+feat_os_unix_musl = [
+  "feat_Tier1",
+  #
+  "feat_require_unix_musl",
+  "feat_require_unix_hostid",
+  "feat_require_unix_utmpx",
+]
 # "feat_os_windows" == set of utilities which can be built/run on modern/usual windows platforms
 feat_os_windows = [
   "feat_Tier1", ## == "feat_os_windows_legacy" + "hostname"
@@ -194,7 +202,11 @@ feat_os_unix_android = [
 # ** NOTE: these `feat_require_...` sets should be minimized as much as possible to encourage cross-platform availability of utilities
 #
 # "feat_require_unix" == set of utilities requiring support which is only available on unix platforms
-feat_require_unix = [
+feat_require_unix = ["feat_require_unix_core", "stdbuf"]
+# "feat_require_unix_musl" == set of utilities requiring unix support, excluding stdbuf (cdylib not supported on musl)
+feat_require_unix_musl = ["feat_require_unix_core"]
+# "feat_require_unix_core" == core unix utilities (shared between regular unix and musl)
+feat_require_unix_core = [
   "chgrp",
   "chmod",
   "chown",
@@ -210,7 +222,6 @@ feat_require_unix = [
   "nohup",
   "pathchk",
   "stat",
-  "stdbuf",
   "stty",
   "timeout",
   "tty",

tests/test_util_name.rs

@@ -280,3 +280,38 @@ fn util_version() {
         assert_eq!(format!("coreutils {ver} (multi-call binary)\n"), output_str);
     }
 }
+
+#[test]
+#[cfg(target_env = "musl")]
+fn test_musl_no_dynamic_deps() {
+    use std::process::Command;
+
+    let binary_path = if cfg!(debug_assertions) {
+        "target/x86_64-unknown-linux-musl/debug/coreutils"
+    } else {
+        "target/x86_64-unknown-linux-musl/release/coreutils"
+    };
+
+    let output = Command::new("/lib/ld-musl-x86_64.so.1")
+        .arg("--list")
+        .arg(binary_path)
+        .output()
+        .expect("Failed to run musl loader");
+
+    let stdout = String::from_utf8_lossy(&output.stdout);
+    let lines: Vec<&str> = stdout.trim().lines().collect();
+
+    // Should only show the musl loader itself (statically linked binary)
+    assert_eq!(
+        lines.len(),
+        1,
+        "Expected only musl loader, but found dynamic dependencies: {:?}",
+        lines
+    );
+
+    assert!(
+        lines[0].contains("ld-musl"),
+        "Expected musl loader path, got: {}",
+        lines[0]
+    );
+}