update

Author: tgross35

crates/symbol-check/build.rs

@@ -1,11 +1,21 @@
 fn main() {
-    let intermediates = cc::Build::new()
-        .file("has_wx.c")
-        .try_compile_intermediates();
-    if let Ok(list) = intermediates {
-        let [obj] = list.as_slice() else {
-            panic!(">1 output")
-        };
-        println!("cargo::rustc-env=HAS_WX_OBJ={}", obj.display());
+    let objs = cc::Build::new()
+        .file("tests/no_gnu_stack.S")
+        .compile_intermediates();
+    let [obj] = objs.as_slice() else {
+        panic!(">1 output")
+    };
+    println!("cargo::rustc-env=NO_GNU_STACK_OBJ={}", obj.display());
+
+    let mut b = cc::Build::new();
+    if !b.get_compiler().is_like_gnu() {
+        println!("cargo::warning=Can't run execstack test; non-GNU compiler");
+        return;
     }
+
+    let objs = b.file("tests/has_exe_stack.c").compile_intermediates();
+    let [obj] = objs.as_slice() else {
+        panic!(">1 output")
+    };
+    println!("cargo::rustc-env=HAS_EXE_STACK_OBJ={}", obj.display());
 }

crates/symbol-check/src/main.rs

@@ -10,8 +10,8 @@ use std::process::{Command, Stdio};
 use object::elf::SHF_EXECINSTR;
 use object::read::archive::{ArchiveFile, ArchiveMember};
 use object::{
-    File as ObjFile, Object, ObjectSection, ObjectSymbol, SectionFlags, Symbol, SymbolKind,
-    SymbolScope,
+    BinaryFormat, File as ObjFile, Object, ObjectSection, ObjectSymbol, SectionFlags, Symbol,
+    SymbolKind, SymbolScope,
 };
 use serde_json::Value;
 
@@ -309,6 +309,9 @@ fn verify_core_symbols(archive: &Archive) {
 /// - A `.note.GNU-stack` section without the exe flag means there is no executable stack needed
 /// - Without the section, behavior is target-specific and on some targets means an executable
 ///   stack is required.
+///
+/// Now says
+/// deprecated <https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=0d38576a34ec64a1b4500c9277a8e9d0f07e6774>.
 fn verify_no_exec_stack(archive: &Archive) {
     let mut problem_objfiles = Vec::new();
 
@@ -327,7 +330,7 @@ fn verify_no_exec_stack(archive: &Archive) {
 
 fn obj_requires_exe_stack(obj: &ObjFile) -> bool {
     // Files other than elf likely do not use the same convention.
-    if !matches!(obj, ObjFile::Elf32(_) | ObjFile::Elf64(_)) {
+    if obj.format() != BinaryFormat::Elf {
         return false;
     }
 
@@ -395,9 +398,18 @@ impl Archive {
     }
 }
 
+#[test]
+fn check_no_gnu_stack_obj() {
+    // Should be supported on all Unix platforms
+    let p = env!("NO_GNU_STACK_OBJ");
+    let f = fs::read(p).unwrap();
+    let obj = ObjFile::parse(f.as_slice()).unwrap();
+    assert!(obj_requires_exe_stack(&obj));
+}
+
 #[test]
 fn check_obj() {
-    let p = option_env!("HAS_WX_OBJ").expect("this platform should support the wx test build");
+    let p = option_env!("HAS_EXE_STACK_OBJ").expect("has_exe_stack.o not present");
     let f = fs::read(p).unwrap();
     let obj = ObjFile::parse(f.as_slice()).unwrap();
     assert!(obj_requires_exe_stack(&obj));

crates/symbol-check/has_wx.c renamed to crates/symbol-check/tests/has_exe_stack.c

@@ -1,3 +1,6 @@
+/* GNU nested functions are the only way I could fine to force an executable
+ * stack. Supported by GCC only, not Clang. */
+
 void intermediate(void (*)(int, int), int);
 
 int hack(int *array, int size) {

crates/symbol-check/tests/no_gnu_stack.S

@@ -0,0 +1,3 @@
+; Assembly files do not get a `.note.GNU-stack` section, meaning executable
+; by default.
+nop