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

Author: devnexen

compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp

@@ -292,6 +292,18 @@ 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);
+}
+
+#if SANITIZER_APPLE
+INTERCEPTOR(int, fpurge, FILE *stream) {
+  __rtsan_notify_intercepted_call("fpurge");
+  return REAL(fpurge)(stream);
+}
+#endif
+
 INTERCEPTOR(FILE *, fdopen, int fd, const char *mode) {
   __rtsan_notify_intercepted_call("fdopen");
   return REAL(fdopen)(fd, mode);
@@ -981,6 +993,7 @@ 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;

compiler-rt/lib/rtsan/tests/rtsan_test_interceptors_posix.cpp

@@ -604,6 +604,34 @@ TEST_F(RtsanOpenedFileTest, FputsDiesWhenRealtime) {
   ExpectNonRealtimeSurvival(Func);
 }
 
+TEST_F(RtsanFileTest, FflushDiesWhenRealtime) {
+  FILE *f = fopen(GetTemporaryFilePath(), "w");
+  EXPECT_THAT(f, Ne(nullptr));
+  int written = fwrite("abc", 1, 3, f);
+  EXPECT_THAT(written, Eq(3));
+  auto Func = [&f]() {
+    int res = fflush(f);
+    EXPECT_THAT(res, Eq(0));
+  };
+  ExpectRealtimeDeath(Func, "fflush");
+  ExpectNonRealtimeSurvival(Func);
+}
+
+#if SANITIZER_APPLE
+TEST_F(RtsanFileTest, FpurgeDiesWhenRealtime) {
+  FILE *f = fopen(GetTemporaryFilePath(), "w");
+  EXPECT_THAT(f, Ne(nullptr));
+  int written = fwrite("abc", 1, 3, f);
+  EXPECT_THAT(written, Eq(3));
+  auto Func = [&f]() {
+    int res = fpurge(f);
+    EXPECT_THAT(res, Eq(0));
+  };
+  ExpectRealtimeDeath(Func, "fpurge");
+  ExpectNonRealtimeSurvival(Func);
+}
+#endif
+
 TEST_F(RtsanOpenedFileTest, ReadDiesWhenRealtime) {
   auto Func = [this]() {
     char c{};