[compiler-rt] [compiler-rt][rtsan] truncate/ftruncate interception. (PR #128904)

[David CARLIER via llvm-commits]

https://github.com/devnexen created https://github.com/llvm/llvm-project/pull/128904

None

>From c03d3f05b7481c3101d20e07ee43126260dfd935 Mon Sep 17 00:00:00 2001
From: David Carlier <devnexen at gmail.com>
Date: Wed, 26 Feb 2025 16:29:22 +0000
Subject: [PATCH] [compiler-rt][rtsan] truncate/ftruncate interception.

---
 .../lib/rtsan/rtsan_interceptors_posix.cpp    | 31 +++++++++++++++++++
 .../tests/rtsan_test_interceptors_posix.cpp   | 16 ++++++++--
 2 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp b/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp
index 5b9e992639f55..d41af795db724 100644
--- a/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp
+++ b/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp
@@ -285,6 +285,33 @@ INTERCEPTOR(int, unlinkat, int fd, const char *pathname, int flag) {
   return REAL(unlinkat)(fd, pathname, flag);
 }
 
+INTERCEPTOR(int, truncate, const char *pathname, off_t length) {
+  __rtsan_notify_intercepted_call("truncate");
+  return REAL(truncate)(pathname, length);
+}
+
+INTERCEPTOR(int, ftruncate, int fd, off_t length) {
+  __rtsan_notify_intercepted_call("ftruncate");
+  return REAL(ftruncate)(fd, length);
+}
+
+#if SANITIZER_LINUX
+INTERCEPTOR(int, truncate64, const char *pathname, off64_t length) {
+  __rtsan_notify_intercepted_call("truncate64");
+  return REAL(truncate64)(pathname, length);
+}
+
+INTERCEPTOR(int, ftruncate64, int fd, off64_t length) {
+  __rtsan_notify_intercepted_call("ftruncate64");
+  return REAL(ftruncate64)(fd, length);
+}
+#define RTSAN_MAYBE_INTERCEPT_TRUNCATE64 INTERCEPT_FUNCTION(truncate64)
+#define RTSAN_MAYBE_INTERCEPT_FTRUNCATE64 INTERCEPT_FUNCTION(ftruncate64)
+#else
+#define RTSAN_MAYBE_INTERCEPT_TRUNCATE64
+#define RTSAN_MAYBE_INTERCEPT_FTRUNCATE64
+#endif
+
 // Streams
 
 INTERCEPTOR(FILE *, fopen, const char *path, const char *mode) {
@@ -1437,6 +1464,10 @@ void __rtsan::InitializeInterceptors() {
   RTSAN_MAYBE_INTERCEPT_READLINKAT;
   INTERCEPT_FUNCTION(unlink);
   INTERCEPT_FUNCTION(unlinkat);
+  INTERCEPT_FUNCTION(truncate);
+  INTERCEPT_FUNCTION(ftruncate);
+  RTSAN_MAYBE_INTERCEPT_TRUNCATE64;
+  RTSAN_MAYBE_INTERCEPT_FTRUNCATE64;
   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 d1c5a94c12213..47bcafff51a4d 100644
--- a/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors_posix.cpp
+++ b/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors_posix.cpp
@@ -401,7 +401,7 @@ TEST_F(RtsanFileTest, FcntlFlockDiesWhenRealtime) {
   ASSERT_THAT(fd, Ne(-1));
 
   auto Func = [fd]() {
-    struct flock lock {};
+    struct flock lock{};
     lock.l_type = F_RDLCK;
     lock.l_whence = SEEK_SET;
     lock.l_start = 0;
@@ -735,7 +735,7 @@ TEST(TestRtsanInterceptors, IoctlBehavesWithOutputPointer) {
     GTEST_SKIP();
   }
 
-  struct ifreq ifr {};
+  struct ifreq ifr{};
   strncpy(ifr.ifr_name, ifaddr->ifa_name, IFNAMSIZ - 1);
 
   int retval = ioctl(sock, SIOCGIFADDR, &ifr);
@@ -875,6 +875,18 @@ TEST_F(RtsanOpenedFileTest, UnlinkatDiesWhenRealtime) {
   ExpectNonRealtimeSurvival(Func);
 }
 
+TEST_F(RtsanOpenedFileTest, TruncateDiesWhenRealtime) {
+  auto Func = [&]() { truncate(GetTemporaryFilePath(), 16); };
+  ExpectRealtimeDeath(Func, MAYBE_APPEND_64("truncate"));
+  ExpectNonRealtimeSurvival(Func);
+}
+
+TEST_F(RtsanOpenedFileTest, FtruncateDiesWhenRealtime) {
+  auto Func = [&]() { ftruncate(GetOpenFd(), 16); };
+  ExpectRealtimeDeath(Func, MAYBE_APPEND_64("ftruncate"));
+  ExpectNonRealtimeSurvival(Func);
+}
+
 TEST_F(RtsanFileTest, FcloseDiesWhenRealtime) {
   FILE *f = fopen(GetTemporaryFilePath(), "w");
   EXPECT_THAT(f, Ne(nullptr));