Reapply "[compiler-rt] adding preadv2/pwritev2 interceptions." (llvm#99085)

This reverts commit 81704f6.

Author: devnexen

compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc

@@ -10264,6 +10264,38 @@ 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 {
@@ -10583,6 +10615,8 @@ static void InitializeCommonInterceptors() {
   INIT___XUNAME;
   INIT_ARGP_PARSE;
   INIT_CPUSET_GETAFFINITY;
+  INIT_PREADV2;
+  INIT_PWRITEV2;
 
   INIT___PRINTF_CHK;
 }

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

compiler-rt/test/sanitizer_common/TestCases/Linux/preadv2.cpp

@@ -0,0 +1,28 @@
+// RUN: %clangxx -O0 %s -o %t
+
+// REQUIRES: glibc
+
+#include <assert.h>
+#include <fcntl.h>
+#include <sys/uio.h>
+#include <unistd.h>
+
+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);
+  rd = preadv2(fd, vec, 5, -25, 0);
+  assert(rd < 0);
+  close(fd);
+  return 0;
+}