[compiler-rt] [compiler-rt][rtsan] copy_file_range interception for Linux. (PR #129026)

[David CARLIER via llvm-commits]

https://github.com/devnexen updated https://github.com/llvm/llvm-project/pull/129026

>From 0c72036bf7ec39925dd42c9c2448614cb82cdf17 Mon Sep 17 00:00:00 2001
From: David Carlier <devnexen at gmail.com>
Date: Thu, 27 Feb 2025 09:34:07 +0000
Subject: [PATCH 1/2] [compiler-rt][rtsan] copy_file_range interception for
 Linux.

glibc had the wrapper for years and musl since 5yrs+, hopefully should
not need to address the latter.
---
 compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp  | 13 +++++++++++++
 .../rtsan/tests/rtsan_test_interceptors_posix.cpp   | 11 +++++++++++
 2 files changed, 24 insertions(+)

diff --git a/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp b/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp
index d41af795db724..ae85b1d3150e2 100644
--- a/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp
+++ b/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp
@@ -312,6 +312,18 @@ INTERCEPTOR(int, ftruncate64, int fd, off64_t length) {
 #define RTSAN_MAYBE_INTERCEPT_FTRUNCATE64
 #endif
 
+#if SANITIZER_LINUX
+INTERCEPTOR(ssize_t, copy_file_range, int fdin, off_t *off_int, int fdout,
+            off_t *off_out, size_t len, unsigned int flags) {
+  __rtsan_notify_intercepted_call("copy_file_range");
+  return REAL(copy_file_range)(fdin, off_int, fdout, off_out, len, flags);
+}
+#define RTSAN_MAYBE_INTERCEPT_COPY_FILE_RANGE                                  \
+  INTERCEPT_FUNCTION(copy_file_range)
+#else
+#define RTSAN_MAYBE_INTERCEPT_COPY_FILE_RANGE
+#endif
+
 // Streams
 
 INTERCEPTOR(FILE *, fopen, const char *path, const char *mode) {
@@ -1468,6 +1480,7 @@ void __rtsan::InitializeInterceptors() {
   INTERCEPT_FUNCTION(ftruncate);
   RTSAN_MAYBE_INTERCEPT_TRUNCATE64;
   RTSAN_MAYBE_INTERCEPT_FTRUNCATE64;
+  RTSAN_MAYBE_INTERCEPT_COPY_FILE_RANGE;
   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 47bcafff51a4d..d1fc24113db6c 100644
--- a/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors_posix.cpp
+++ b/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors_posix.cpp
@@ -887,6 +887,17 @@ TEST_F(RtsanOpenedFileTest, FtruncateDiesWhenRealtime) {
   ExpectNonRealtimeSurvival(Func);
 }
 
+#if _FILE_OFFSET_BITS == 64 && SANITIZER_LINUX
+TEST_F(RtsanOpenedFileTest, CopyfilerangeDiesWhenRealtime) {
+  off_t in = 0, out = 1;
+  auto Func = [this, &in, &out]() {
+    copy_file_range(GetOpenFd(), &in, GetOpenFd(), &out, 1, 0);
+  };
+  ExpectRealtimeDeath(Func, "copy_file_range");
+  ExpectNonRealtimeSurvival(Func);
+}
+#endif
+
 TEST_F(RtsanFileTest, FcloseDiesWhenRealtime) {
   FILE *f = fopen(GetTemporaryFilePath(), "w");
   EXPECT_THAT(f, Ne(nullptr));

>From 72f75c4c0bcfd89a5eb40231d8cfc15a279e0b8f Mon Sep 17 00:00:00 2001
From: David Carlier <devnexen at gmail.com>
Date: Thu, 27 Feb 2025 11:59:22 +0000
Subject: [PATCH 2/2] enable LFS for Linux so copy_file_range can be properly
 intercepted.

---
 compiler-rt/lib/rtsan/CMakeLists.txt               | 3 +++
 compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/compiler-rt/lib/rtsan/CMakeLists.txt b/compiler-rt/lib/rtsan/CMakeLists.txt
index a4413d9992b62..c08cfd41aa4e6 100644
--- a/compiler-rt/lib/rtsan/CMakeLists.txt
+++ b/compiler-rt/lib/rtsan/CMakeLists.txt
@@ -31,6 +31,9 @@ set(RTSAN_CFLAGS
   ${COMPILER_RT_COMMON_CFLAGS}
   ${COMPILER_RT_CXX_CFLAGS}
   -DSANITIZER_COMMON_NO_REDEFINE_BUILTINS)
+if (OS_NAME MATCHES "Linux")
+	set(RTSAN_CFLAGS ${RTSAN_CFLAGS} -D_FILE_OFFSET_BITS=64)
+endif()
 set(RTSAN_LINK_FLAGS ${COMPILER_RT_COMMON_LINK_FLAGS})
 set(RTSAN_DYNAMIC_LIBS
   ${COMPILER_RT_UNWINDER_LINK_LIBS}
diff --git a/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp b/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp
index ae85b1d3150e2..ace7df6568879 100644
--- a/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp
+++ b/compiler-rt/lib/rtsan/rtsan_interceptors_posix.cpp
@@ -312,7 +312,7 @@ INTERCEPTOR(int, ftruncate64, int fd, off64_t length) {
 #define RTSAN_MAYBE_INTERCEPT_FTRUNCATE64
 #endif
 
-#if SANITIZER_LINUX
+#if _FILE_OFFSET_BITS == 64 && SANITIZER_LINUX
 INTERCEPTOR(ssize_t, copy_file_range, int fdin, off_t *off_int, int fdout,
             off_t *off_out, size_t len, unsigned int flags) {
   __rtsan_notify_intercepted_call("copy_file_range");