[compiler-rt] [compiler-rt][rtsan] adding readlink(a) interception (PR #126262)

[David CARLIER via llvm-commits]

https://github.com/devnexen created https://github.com/llvm/llvm-project/pull/126262

None

>From 5a6d9fec054d5b32522d2a22fa0c1c6531906ec6 Mon Sep 17 00:00:00 2001
From: David Carlier <devnexen at gmail.com>
Date: Fri, 7 Feb 2025 16:41:04 +0000
Subject: [PATCH] [compiler-rt][rtsan] adding readlink(a) interception

---
 .../lib/rtsan/rtsan_interceptors_posix.cpp    | 23 +++++++++++++++++++
 .../tests/rtsan_test_interceptors_posix.cpp   | 18 +++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp b/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp
index 83e6cdd4a009410..410da0748b43348 100644
--- a/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp
+++ b/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp
@@ -254,6 +254,27 @@ INTERCEPTOR(int, fchdir, int fd) {
   return REAL(fchdir)(fd);
 }
 
+#if SANITIZER_INTERCEPT_READLINK
+INTERCEPTOR(ssize_t, readlink, const char *pathname, char *buf, size_t size) {
+  __rtsan_notify_intercepted_call("readlink");
+  return REAL(readlink)(pathname, buf, size);
+}
+#define RTSAN_MAYBE_INTERCEPT_READLINK INTERCEPT_FUNCTION(readlink)
+#else
+#define RTSAN_MAYBE_INTERCEPT_READLINK
+#endif
+
+#if SANITIZER_INTERCEPT_READLINKAT
+INTERCEPTOR(ssize_t, readlinkat, int dirfd, const char *pathname, char *buf,
+            size_t size) {
+  __rtsan_notify_intercepted_call("readlinkat");
+  return REAL(readlinkat)(dirfd, pathname, buf, size);
+}
+#define RTSAN_MAYBE_INTERCEPT_READLINKAT INTERCEPT_FUNCTION(readlinkat)
+#else
+#define RTSAN_MAYBE_INTERCEPT_READLINKAT
+#endif
+
 // Streams
 
 INTERCEPTOR(FILE *, fopen, const char *path, const char *mode) {
@@ -1402,6 +1423,8 @@ void __rtsan::InitializeInterceptors() {
   INTERCEPT_FUNCTION(close);
   INTERCEPT_FUNCTION(chdir);
   INTERCEPT_FUNCTION(fchdir);
+  RTSAN_MAYBE_INTERCEPT_READLINK;
+  RTSAN_MAYBE_INTERCEPT_READLINKAT;
   INTERCEPT_FUNCTION(fopen);
   RTSAN_MAYBE_INTERCEPT_FOPEN64;
   RTSAN_MAYBE_INTERCEPT_FREOPEN64;
diff --git a/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors_posix.cpp b/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors_posix.cpp
index 075f5974b7562a8..98d27caae94b81e 100644
--- a/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors_posix.cpp
+++ b/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors_posix.cpp
@@ -457,6 +457,24 @@ TEST(TestRtsanInterceptors, FchdirDiesWhenRealtime) {
   ExpectNonRealtimeSurvival(Func);
 }
 
+#if SANITIZER_INTERCEPT_READLINK
+TEST(TestRtsanInterceptors, ReadlinkDiesWhenRealtime) {
+  char buf[1024];
+  auto Func = [&buf]() { readlink("/proc/self", buf, sizeof(buf)); };
+  ExpectRealtimeDeath(Func, "readlink");
+  ExpectNonRealtimeSurvival(Func);
+}
+#endif
+
+#if SANITIZER_INTERCEPT_READLINKAT
+TEST(TestRtsanInterceptors, ReadlinkatDiesWhenRealtime) {
+  char buf[1024];
+  auto Func = [&buf]() { readlinkat(0, "/proc/self", buf, sizeof(buf)); };
+  ExpectRealtimeDeath(Func, "readlinkat");
+  ExpectNonRealtimeSurvival(Func);
+}
+#endif
+
 TEST_F(RtsanFileTest, FopenDiesWhenRealtime) {
   auto Func = [this]() {
     FILE *f = fopen(GetTemporaryFilePath(), "w");