| //===-- interception_linux.cpp ----------------------------------*- C++ -*-===// |
| // |
| // 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 |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file is a part of AddressSanitizer, an address sanity checker. |
| // |
| // Linux-specific interception methods. |
| //===----------------------------------------------------------------------===// |
| |
| #include "interception.h" |
| |
| #if SANITIZER_LINUX || SANITIZER_FREEBSD || SANITIZER_NETBSD || \ |
| SANITIZER_SOLARIS |
| |
| #include <dlfcn.h> // for dlsym() and dlvsym() |
| |
| namespace __interception { |
| |
| #if SANITIZER_NETBSD |
| static int StrCmp(const char *s1, const char *s2) { |
| while (true) { |
| if (*s1 != *s2) |
| return false; |
| if (*s1 == 0) |
| return true; |
| s1++; |
| s2++; |
| } |
| } |
| #endif |
| |
| static void *GetFuncAddr(const char *name, uptr trampoline) { |
| #if SANITIZER_NETBSD |
| // FIXME: Find a better way to handle renames |
| if (StrCmp(name, "sigaction")) |
| name = "__sigaction14"; |
| #endif |
| 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. |
| 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 == trampoline) |
| addr = nullptr; |
| } |
| return addr; |
| } |
| |
| bool InterceptFunction(const char *name, uptr *ptr_to_real, uptr func, |
| uptr trampoline) { |
| void *addr = GetFuncAddr(name, trampoline); |
| *ptr_to_real = (uptr)addr; |
| return addr && (func == trampoline); |
| } |
| |
| // dlvsym is a GNU extension supported by some other platforms. |
| #if SANITIZER_GLIBC || SANITIZER_FREEBSD || SANITIZER_NETBSD |
| 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 trampoline) { |
| void *addr = GetFuncAddr(name, ver); |
| *ptr_to_real = (uptr)addr; |
| return addr && (func == trampoline); |
| } |
| # endif // SANITIZER_GLIBC || SANITIZER_FREEBSD || SANITIZER_NETBSD |
| |
| } // namespace __interception |
| |
| #endif // SANITIZER_LINUX || SANITIZER_FREEBSD || SANITIZER_NETBSD || |
| // SANITIZER_SOLARIS |