[compiler-rt] [compiler-rt] adding preadv2/pwritev2 interceptions. (PR #97216)

[David CARLIER via llvm-commits]

https://github.com/devnexen updated https://github.com/llvm/llvm-project/pull/97216

>From e4606ed2d03d4bab20eca2a95ed73b622fdf54ab Mon Sep 17 00:00:00 2001
From: David Carlier <devnexen at gmail.com>
Date: Sun, 30 Jun 2024 15:29:17 +0100
Subject: [PATCH 1/2] [compiler-rt] adding preadv2/pwritev2 interceptions.

---
 .../sanitizer_common_interceptors.inc         | 34 +++++++++++++++++++
 .../sanitizer_platform_interceptors.h         |  3 ++
 2 files changed, 37 insertions(+)

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
index 1df61e79f7d84..eae0e8ebba1f7 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -10259,6 +10259,38 @@ INTERCEPTOR(int, cpuset_getaffinity, int level, int which, __int64_t id, SIZE_T
 #define INIT_CPUSET_GETAFFINITY
 #endif
 
+#if SANITIZER_INTERCEPT_PREADV2
+INTERCEPTOR(SSIZE_T, preadv2, int fd, __sanitizer_iovec *iov, int iovcnt,
+            OFF_T offset, int flags) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, preadv2, fd, iov, iovcnt, offset, flags);
+  COMMON_INTERCEPTOR_FD_ACCESS(ctx, fd);
+  SSIZE_T res = REAL(preadv2)(fd, iov, iovcnt, offset, flags);
+  if (res > 0) write_iovec(ctx, iov, iovcnt, res);
+  if (res >= 0 && fd >= 0) COMMON_INTERCEPTOR_FD_ACQUIRE(ctx, fd);
+  return res;
+}
+#define INIT_PREADV2 COMMON_INTERCEPT_FUNCTION(preadv2)
+#else
+#define INIT_PREADV2
+#endif
+
+#if SANITIZER_INTERCEPT_PWRITEV2
+INTERCEPTOR(SSIZE_T, pwritev2, int fd, __sanitizer_iovec *iov, int iovcnt,
+            OFF_T offset, int flags) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, pwritev2, fd, iov, iovcnt, offset, flags);
+  COMMON_INTERCEPTOR_FD_ACCESS(ctx, fd);
+  if (fd >= 0) COMMON_INTERCEPTOR_FD_RELEASE(ctx, fd);
+  SSIZE_T res = REAL(pwritev2)(fd, iov, iovcnt, offset, flags);
+  if (res > 0) read_iovec(ctx, iov, iovcnt, res);
+  return res;
+}
+#define INIT_PWRITEV2 COMMON_INTERCEPT_FUNCTION(pwritev2)
+#else
+#define INIT_PWRITEV2
+#endif
+
 #include "sanitizer_common_interceptors_netbsd_compat.inc"
 
 namespace __sanitizer {
@@ -10578,6 +10610,8 @@ static void InitializeCommonInterceptors() {
   INIT___XUNAME;
   INIT_ARGP_PARSE;
   INIT_CPUSET_GETAFFINITY;
+  INIT_PREADV2;
+  INIT_PWRITEV2;
 
   INIT___PRINTF_CHK;
 }
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
index de55c736d0e14..c94368b6b0ebb 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
@@ -598,6 +598,9 @@
 #define SANITIZER_INTERCEPT_PROCCTL SI_FREEBSD
 #define SANITIZER_INTERCEPT_ARGP_PARSE SI_GLIBC
 #define SANITIZER_INTERCEPT_CPUSET_GETAFFINITY SI_FREEBSD
+// FIXME: also available from musl 1.2.5
+#define SANITIZER_INTERCEPT_PREADV2 SI_GLIBC
+#define SANITIZER_INTERCEPT_PWRITEV2 SI_GLIBC
 
 // This macro gives a way for downstream users to override the above
 // interceptor macros irrespective of the platform they are on. They have

>From 3187014eb9804acffc94eca064c620cc96c8294a Mon Sep 17 00:00:00 2001
From: David Carlier <devnexen at gmail.com>
Date: Thu, 11 Jul 2024 23:05:01 +0100
Subject: [PATCH 2/2] add tests

---
 .../TestCases/Linux/preadv2.cpp               | 32 +++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 compiler-rt/test/sanitizer_common/TestCases/Linux/preadv2.cpp

diff --git a/compiler-rt/test/sanitizer_common/TestCases/Linux/preadv2.cpp b/compiler-rt/test/sanitizer_common/TestCases/Linux/preadv2.cpp
new file mode 100644
index 0000000000000..df2c5f8fc24fa
--- /dev/null
+++ b/compiler-rt/test/sanitizer_common/TestCases/Linux/preadv2.cpp
@@ -0,0 +1,32 @@
+// RUN: %clangxx -O0 %s -o %t && %run %t
+// RUN: %env_tool_opts=handle_segv=2 not %run %t 3 2>&1 | FileCheck --check-prefixes=CHECK1,CHECK
+
+// UNSUPPORTED: android
+
+#include <assert.h>
+#include <fcntl.h>
+#include <sys/uio.h>
+#include <unistd.h>
+
+// CHECK: [[SAN:.*Sanitizer]]:DEADLYSIGNAL
+// CHECK: ERROR: [[SAN]]: SEGV on unknown address {{0x[^ ]*}} (pc
+int main(void) {
+  int fd = open("/proc/self/stat", O_RDONLY);
+  char bufa[7];
+  char bufb[7];
+  struct iovec vec[2];
+  vec[0].iov_base = bufa + 4;
+  vec[0].iov_len = 1;
+  vec[1].iov_base = bufb;
+  vec[1].iov_len = sizeof(bufb);
+  ssize_t rd = preadv2(fd, vec, 2, 0, 0);
+  assert(rd > 0);
+  vec[0].iov_base = bufa;
+  rd = preadv2(fd, vec, 2, 0, 0);
+  assert(rd > 0);
+  vec[1].iov_len = 1024;
+  preadv2(fd, vec, 2, 0, 0);
+  // CHECK1: #{{[0-9]+ .*}}main {{.*}}preadv2.cpp:[[@LINE-1]]:[[TAB:[0-9]+]]
+  // CHECK1: SUMMARY: [[SAN]]: SEGV {{.*}}preadv2.cpp:[[@LINE-2]]:[[TAB]] in main
+  return 0;
+}