ensure static executable using fspy_shared_unix::is_dynamically_linked_to_lib

Author: wan9chi

crates/fspy/tests/static_executable.rs

@@ -4,36 +4,32 @@ use std::{
     fs::{self, Permissions},
     os::unix::fs::PermissionsExt as _,
     path::{Path, PathBuf},
-    str::from_utf8,
     sync::LazyLock,
 };
 
 use fspy::PathAccessIterable;
+use fspy_shared_unix::is_dynamically_linked_to_libc;
 
 use crate::test_utils::assert_contains;
 
 mod test_utils;
 
-const PRELOAD_CDYLIB_BINARY: &[u8] = include_bytes!(env!("CARGO_BIN_FILE_FSPY_TEST_BIN"));
+const TEST_BIN_CONTENT: &[u8] = include_bytes!(env!("CARGO_BIN_FILE_FSPY_TEST_BIN"));
 
 fn test_bin_path() -> &'static Path {
     static TEST_BIN_PATH: LazyLock<PathBuf> = LazyLock::new(|| {
+        assert_eq!(
+            is_dynamically_linked_to_libc(&TEST_BIN_CONTENT),
+            Ok(false),
+            "Test binary is not a static executable"
+        );
+
         let tmp_dir = env!("CARGO_TARGET_TMPDIR");
         let test_bin_path = PathBuf::from(tmp_dir).join("fspy-test-bin");
-        fs::write(&test_bin_path, PRELOAD_CDYLIB_BINARY).expect("failed to write test binary");
+        fs::write(&test_bin_path, TEST_BIN_CONTENT).expect("failed to write test binary");
         fs::set_permissions(&test_bin_path, Permissions::from_mode(0o755))
             .expect("failed to set permissions on test binary");
 
-        // Verify that the test binary is indeed a static executable
-        let output = std::process::Command::new("ldd").arg(&test_bin_path).output().unwrap();
-        assert_eq!(
-            output.status.code(),
-            Some(1),
-            "ldd should fail on static executables. Stdout: {}. Stderr: {}",
-            from_utf8(&output.stdout).unwrap(),
-            from_utf8(&output.stderr).unwrap()
-        );
-
         test_bin_path
     });
     TEST_BIN_PATH.as_path()

…/fspy_shared_unix/src/spawn/linux/elf.rs crates/fspy_shared_unix/src/elf.rscrates/fspy_shared_unix/src/spawn/linux/elf.rs renamed to crates/fspy_shared_unix/src/elf.rs crates/fspy_shared_unix/src/spawn/linux/elf.rs renamed to crates/fspy_shared_unix/src/elf.rs

@@ -4,3 +4,9 @@ pub mod exec;
 pub(crate) mod open_exec;
 pub mod payload;
 pub mod spawn;
+
+#[cfg(target_os = "linux")]
+mod elf;
+
+#[cfg(target_os = "linux")] // exposed for verifying static executables in fspy tests
+pub use elf::is_dynamically_linked_to_libc;

crates/fspy_shared_unix/src/lib.rs

@@ -1,11 +1,10 @@
-mod elf;
-
 use std::{ffi::OsStr, os::unix::ffi::OsStrExt as _, path::Path};
 
 use fspy_seccomp_unotify::{payload::SeccompPayload, target::install_target};
 use memmap2::Mmap;
 
 use crate::{
+    elf,
     exec::{Exec, ensure_env},
     open_exec::open_executable,
     payload::{EncodedPayload, PAYLOAD_ENV_NAME},