[compiler-rt] [compiler-rt][rtsan] intercept fflush. (PR #121643)

[David CARLIER via llvm-commits]

https://github.com/devnexen created https://github.com/llvm/llvm-project/pull/121643

None

>From 945d1f75f9160becb50d8655b26fdfde14131d50 Mon Sep 17 00:00:00 2001
From: David Carlier <devnexen at gmail.com>
Date: Sat, 4 Jan 2025 12:00:59 +0000
Subject: [PATCH] [compiler-rt][rtsan] intercept fflush.

---
 compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp  |  6 ++++++
 .../rtsan/tests/rtsan_test_interceptors_posix.cpp   | 13 +++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp b/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp
index 227d077290af71..d1988c3ace04c4 100644
--- a/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp
+++ b/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp
@@ -292,6 +292,11 @@ INTERCEPTOR(int, fputs, const char *s, FILE *stream) {
   return REAL(fputs)(s, stream);
 }
 
+INTERCEPTOR(int, fflush, FILE *stream) {
+  __rtsan_notify_intercepted_call("fflush");
+  return REAL(fflush)(stream);
+}
+
 INTERCEPTOR(FILE *, fdopen, int fd, const char *mode) {
   __rtsan_notify_intercepted_call("fdopen");
   return REAL(fdopen)(fd, mode);
@@ -1012,6 +1017,7 @@ void __rtsan::InitializeInterceptors() {
   RTSAN_MAYBE_INTERCEPT_CREAT64;
   INTERCEPT_FUNCTION(puts);
   INTERCEPT_FUNCTION(fputs);
+  INTERCEPT_FUNCTION(fflush);
   INTERCEPT_FUNCTION(fdopen);
   INTERCEPT_FUNCTION(freopen);
   RTSAN_MAYBE_INTERCEPT_FOPENCOOKIE;
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 2947510b2cfde8..042fa49a638330 100644
--- a/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors_posix.cpp
+++ b/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors_posix.cpp
@@ -654,6 +654,19 @@ TEST_F(RtsanOpenedFileTest, FputsDiesWhenRealtime) {
   ExpectNonRealtimeSurvival(Func);
 }
 
+TEST_F(RtsanFileTest, FflushDiesWhenRealtime) {
+  FILE *f = fopen(GetTemporaryFilePath(), "w");
+  EXPECT_THAT(f, Ne(nullptr));
+  int r = fwrite("abc", 1, 3, f);
+  EXPECT_THAT(r, Eq(3));
+  auto Func = [&f]() {
+    int r = fflush(f);
+    EXPECT_THAT(r, Eq(0));
+  };
+  ExpectRealtimeDeath(Func, "fflush");
+  ExpectNonRealtimeSurvival(Func);
+}
+
 TEST_F(RtsanOpenedFileTest, ReadDiesWhenRealtime) {
   auto Func = [this]() {
     char c{};