From 73c8f83a08161273aeb4c71917a0e8cf6ba59db8 Mon Sep 17 00:00:00 2001
From: sanana <umutinanerdogan@pm.me>
Date: Sat, 1 Feb 2025 17:36:40 +0300
Subject: [PATCH] tests/rtld: Add test for breadth-first search order

---
 tests/rtld/meson.build              |  1 +
 tests/rtld/search-order/libbar.c    | 19 +++++++++++++++
 tests/rtld/search-order/libfoo.c    |  3 +++
 tests/rtld/search-order/meson.build | 37 +++++++++++++++++++++++++++++
 tests/rtld/search-order/test.c      | 21 ++++++++++++++++
 5 files changed, 81 insertions(+)
 create mode 100644 tests/rtld/search-order/libbar.c
 create mode 100644 tests/rtld/search-order/libfoo.c
 create mode 100644 tests/rtld/search-order/meson.build
 create mode 100644 tests/rtld/search-order/test.c

diff --git a/tests/rtld/meson.build b/tests/rtld/meson.build
index 638e50b32..d32939dad 100644
--- a/tests/rtld/meson.build
+++ b/tests/rtld/meson.build
@@ -13,6 +13,7 @@ rtld_test_cases = [
 	'scope3',
 	'scope4',
 	'scope5',
+	'search-order',
 	'tls_align',
 	'relr',
 	'symver',
diff --git a/tests/rtld/search-order/libbar.c b/tests/rtld/search-order/libbar.c
new file mode 100644
index 000000000..22f09b0fb
--- /dev/null
+++ b/tests/rtld/search-order/libbar.c
@@ -0,0 +1,19 @@
+#include <assert.h>
+#include <dlfcn.h>
+
+#ifdef USE_HOST_LIBC
+#define LIBFOO "libnative-foo.so"
+#else
+#define LIBFOO "libfoo.so"
+#endif
+
+int foo(void);
+
+int bar(void) {
+	return foo() + 0xBABE;
+}
+
+[[constructor]] void init(void) {
+	void *libfoo = dlopen(LIBFOO, RTLD_LOCAL | RTLD_NOW);
+	assert(libfoo);
+}
diff --git a/tests/rtld/search-order/libfoo.c b/tests/rtld/search-order/libfoo.c
new file mode 100644
index 000000000..d62656d0e
--- /dev/null
+++ b/tests/rtld/search-order/libfoo.c
@@ -0,0 +1,3 @@
+int foo(void) {
+	return 0xCAFE0000;
+}
diff --git a/tests/rtld/search-order/meson.build b/tests/rtld/search-order/meson.build
new file mode 100644
index 000000000..dcb5d5847
--- /dev/null
+++ b/tests/rtld/search-order/meson.build
@@ -0,0 +1,37 @@
+patchelf = find_program('patchelf', required: false)
+
+if patchelf.found()
+	# Overwrite LD_LIBRARY_PATH to make meson not fix our shenanigans
+	# Otherwise, meson's LD_LIBRARY_PATH makes this test useless because libfoo
+	# will be found through it instead of failing when libfoo is not found
+	test_env += ['LD_LIBRARY_PATH=']
+	test_native_env += ['LD_LIBRARY_PATH=']
+
+	libfoo = shared_library('foo', 'libfoo.c')
+	libbar_unpatched = shared_library('bar-unpatched', 'libbar.c',
+		dependencies: libc_dep, link_with: libfoo)
+	libbar = custom_target('patch-libbar',
+		command: [patchelf,
+			'--remove-rpath',
+			'--set-soname', 'libbar.so',
+			libbar_unpatched,
+			'--output', '@OUTPUT0@'],
+		output: ['libbar.so'],
+	)
+	test_link_with = [libbar, libfoo]
+
+	libfoo_native = shared_library('native-foo', 'libfoo.c', native: true)
+	libbar_native_unpatched = shared_library('native-bar-unpatched', 'libbar.c',
+		dependencies: rtlib_deps, link_with: libfoo_native, native: true)
+	libbar_native = custom_target('patch-libnative-bar',
+		command: [patchelf,
+			'--remove-rpath',
+			'--set-soname', 'libnative-bar.so',
+			libbar_native_unpatched,
+			'--output', '@OUTPUT0@'],
+		output: ['libnative-bar.so'],
+	)
+	test_native_link_with = [libbar_native, libfoo_native]
+else
+	test_skipped = true
+endif
diff --git a/tests/rtld/search-order/test.c b/tests/rtld/search-order/test.c
new file mode 100644
index 000000000..986311e0c
--- /dev/null
+++ b/tests/rtld/search-order/test.c
@@ -0,0 +1,21 @@
+#include <assert.h>
+#include <dlfcn.h>
+
+#ifdef USE_HOST_LIBC
+#define LIBBAR "libnative-bar.so"
+#else
+#define LIBBAR "libbar.so"
+#endif
+
+int foo();
+int bar();
+
+int main() {
+	void *libbar = dlopen(LIBBAR, RTLD_LOCAL | RTLD_NOW);
+	assert(libbar);
+
+	assert(foo() == (int) 0xCAFE0000);
+	assert(bar() == (int) 0xCAFEBABE);
+
+	return 0;
+}