1 files changed, 44 insertions, 16 deletions

diff --git a/lib/interception/interception_linux.cc b/lib/interception/interception_linux.cc
index 26bfcd8f6794d..4b27102a159c8 100644
--- a/lib/interception/interception_linux.cc
+++ b/lib/interception/interception_linux.cc
@@ -1,9 +1,8 @@
 //===-- interception_linux.cc -----------------------------------*- C++ -*-===//
 //
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
@@ -19,33 +18,62 @@
 
 #include <dlfcn.h>   // for dlsym() and dlvsym()
 
+namespace __interception {
+
 #if SANITIZER_NETBSD
-#include "sanitizer_common/sanitizer_libc.h"
+static int StrCmp(const char *s1, const char *s2) {
+  while (true) {
+    if (*s1 != *s2)
+      return false;
+    if (*s1 == 0)
+      return true;
+    s1++;
+    s2++;
+  }
+}
 #endif
 
-namespace __interception {
-bool GetRealFunctionAddress(const char *func_name, uptr *func_addr,
-    uptr real, uptr wrapper) {
+static void *GetFuncAddr(const char *name, uptr wrapper_addr) {
 #if SANITIZER_NETBSD
-  // XXX: Find a better way to handle renames
-  if (internal_strcmp(func_name, "sigaction") == 0) func_name = "__sigaction14";
+  // FIXME: Find a better way to handle renames
+  if (StrCmp(name, "sigaction"))
+    name = "__sigaction14";
 #endif
-  *func_addr = (uptr)dlsym(RTLD_NEXT, func_name);
-  if (!*func_addr) {
+  void *addr = dlsym(RTLD_NEXT, name);
+  if (!addr) {
     // If the lookup using RTLD_NEXT failed, the sanitizer runtime library is
     // later in the library search order than the DSO that we are trying to
     // intercept, which means that we cannot intercept this function. We still
     // want the address of the real definition, though, so look it up using
     // RTLD_DEFAULT.
-    *func_addr = (uptr)dlsym(RTLD_DEFAULT, func_name);
+    addr = dlsym(RTLD_DEFAULT, name);
+
+    // In case `name' is not loaded, dlsym ends up finding the actual wrapper.
+    // We don't want to intercept the wrapper and have it point to itself.
+    if ((uptr)addr == wrapper_addr)
+      addr = nullptr;
   }
-  return real == wrapper;
+  return addr;
+}
+
+bool InterceptFunction(const char *name, uptr *ptr_to_real, uptr func,
+                       uptr wrapper) {
+  void *addr = GetFuncAddr(name, wrapper);
+  *ptr_to_real = (uptr)addr;
+  return addr && (func == wrapper);
 }
 
 // Android and Solaris do not have dlvsym
 #if !SANITIZER_ANDROID && !SANITIZER_SOLARIS && !SANITIZER_OPENBSD
-void *GetFuncAddrVer(const char *func_name, const char *ver) {
-  return dlvsym(RTLD_NEXT, func_name, ver);
+static void *GetFuncAddr(const char *name, const char *ver) {
+  return dlvsym(RTLD_NEXT, name, ver);
+}
+
+bool InterceptFunction(const char *name, const char *ver, uptr *ptr_to_real,
+                       uptr func, uptr wrapper) {
+  void *addr = GetFuncAddr(name, ver);
+  *ptr_to_real = (uptr)addr;
+  return addr && (func == wrapper);
 }
 #endif  // !SANITIZER_ANDROID