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1//===-- safestack_platform.h ----------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9// This file implements platform specific parts of SafeStack runtime.10// Don't use equivalent functionality from sanitizer_common to avoid dragging11// a large codebase into security sensitive code.12//13//===----------------------------------------------------------------------===//14 15#ifndef SAFESTACK_PLATFORM_H16#define SAFESTACK_PLATFORM_H17 18#include "safestack_util.h"19#include "sanitizer_common/sanitizer_platform.h"20 21#include <dlfcn.h>22#include <errno.h>23#include <stdint.h>24#include <stdio.h>25#include <stdlib.h>26#include <sys/mman.h>27#include <sys/syscall.h>28#include <sys/types.h>29#include <unistd.h>30 31#if !(SANITIZER_NETBSD || SANITIZER_FREEBSD || SANITIZER_LINUX || \32 SANITIZER_SOLARIS)33# error "Support for your platform has not been implemented"34#endif35 36#if SANITIZER_NETBSD37#include <lwp.h>38 39extern "C" void *__mmap(void *, size_t, int, int, int, int, off_t);40#endif41 42#if SANITIZER_FREEBSD43#include <sys/thr.h>44#endif45 46#if SANITIZER_SOLARIS47# include <thread.h>48#endif49 50// Keep in sync with sanitizer_linux.cpp.51//52// Are we using 32-bit or 64-bit Linux syscalls?53// x32 (which defines __x86_64__) has SANITIZER_WORDSIZE == 3254// but it still needs to use 64-bit syscalls.55#if SANITIZER_LINUX && \56 (defined(__x86_64__) || defined(__powerpc64__) || \57 SANITIZER_WORDSIZE == 64 || \58 (defined(__mips__) && defined(_ABIN32) && _MIPS_SIM == _ABIN32))59# define SANITIZER_LINUX_USES_64BIT_SYSCALLS 160#else61# define SANITIZER_LINUX_USES_64BIT_SYSCALLS 062#endif63 64namespace safestack {65 66#if SANITIZER_NETBSD67static void *GetRealLibcAddress(const char *symbol) {68 void *real = dlsym(RTLD_NEXT, symbol);69 if (!real)70 real = dlsym(RTLD_DEFAULT, symbol);71 if (!real) {72 fprintf(stderr, "safestack GetRealLibcAddress failed for symbol=%s",73 symbol);74 abort();75 }76 return real;77}78 79#define _REAL(func, ...) real##_##func(__VA_ARGS__)80#define DEFINE__REAL(ret_type, func, ...) \81 static ret_type (*real_##func)(__VA_ARGS__) = NULL; \82 if (!real_##func) { \83 real_##func = (ret_type(*)(__VA_ARGS__))GetRealLibcAddress(#func); \84 } \85 SFS_CHECK(real_##func);86#endif87 88#if SANITIZER_SOLARIS89# define _REAL(func) _##func90# define DEFINE__REAL(ret_type, func, ...) \91 extern "C" ret_type _REAL(func)(__VA_ARGS__)92 93# if !defined(_LP64) && _FILE_OFFSET_BITS == 6494# define _REAL64(func) _##func##6495# else96# define _REAL64(func) _REAL(func)97# endif98# define DEFINE__REAL64(ret_type, func, ...) \99 extern "C" ret_type _REAL64(func)(__VA_ARGS__)100 101DEFINE__REAL64(void *, mmap, void *a, size_t b, int c, int d, int e, off_t f);102DEFINE__REAL(int, munmap, void *a, size_t b);103DEFINE__REAL(int, mprotect, void *a, size_t b, int c);104#endif105 106using ThreadId = uint64_t;107 108inline ThreadId GetTid() {109#if SANITIZER_NETBSD110 DEFINE__REAL(int, _lwp_self);111 return _REAL(_lwp_self);112#elif SANITIZER_FREEBSD113 long Tid;114 thr_self(&Tid);115 return Tid;116#elif SANITIZER_SOLARIS117 return thr_self();118#else119 return syscall(SYS_gettid);120#endif121}122 123inline int TgKill(pid_t pid, ThreadId tid, int sig) {124#if SANITIZER_NETBSD125 DEFINE__REAL(int, _lwp_kill, int a, int b);126 (void)pid;127 return _REAL(_lwp_kill, tid, sig);128#elif SANITIZER_SOLARIS129 (void)pid;130 errno = thr_kill(tid, sig);131 // TgKill is expected to return -1 on error, not an errno.132 return errno != 0 ? -1 : 0;133#elif SANITIZER_FREEBSD134 return syscall(SYS_thr_kill2, pid, tid, sig);135#else136 // tid is pid_t (int), not ThreadId (uint64_t).137 return syscall(SYS_tgkill, pid, (pid_t)tid, sig);138#endif139}140 141inline void *Mmap(void *addr, size_t length, int prot, int flags, int fd,142 off_t offset) {143#if SANITIZER_NETBSD144 return __mmap(addr, length, prot, flags, fd, 0, offset);145#elif SANITIZER_FREEBSD && (defined(__aarch64__) || defined(__x86_64__))146 return (void *)__syscall(SYS_mmap, addr, length, prot, flags, fd, offset);147#elif SANITIZER_FREEBSD && (defined(__i386__))148 return (void *)syscall(SYS_mmap, addr, length, prot, flags, fd, offset);149#elif SANITIZER_SOLARIS150 return _REAL64(mmap)(addr, length, prot, flags, fd, offset);151#elif SANITIZER_LINUX_USES_64BIT_SYSCALLS152 return (void *)syscall(SYS_mmap, addr, length, prot, flags, fd, offset);153#else154 // mmap2 specifies file offset in 4096-byte units.155 SFS_CHECK(IsAligned(offset, 4096));156 return (void *)syscall(SYS_mmap2, addr, length, prot, flags, fd,157 offset / 4096);158#endif159}160 161inline int Munmap(void *addr, size_t length) {162#if SANITIZER_NETBSD163 DEFINE__REAL(int, munmap, void *a, size_t b);164 return _REAL(munmap, addr, length);165#elif SANITIZER_SOLARIS166 return _REAL(munmap)(addr, length);167#else168 return syscall(SYS_munmap, addr, length);169#endif170}171 172inline int Mprotect(void *addr, size_t length, int prot) {173#if SANITIZER_NETBSD174 DEFINE__REAL(int, mprotect, void *a, size_t b, int c);175 return _REAL(mprotect, addr, length, prot);176#elif SANITIZER_SOLARIS177 return _REAL(mprotect)(addr, length, prot);178#else179 return syscall(SYS_mprotect, addr, length, prot);180#endif181}182 183} // namespace safestack184 185#endif // SAFESTACK_PLATFORM_H186