1 // Copyright (c) 2011, Google Inc. 2 // All rights reserved. 3 // 4 // Redistribution and use in source and binary forms, with or without 5 // modification, are permitted provided that the following conditions are 6 // met: 7 // 8 // * Redistributions of source code must retain the above copyright 9 // notice, this list of conditions and the following disclaimer. 10 // * Redistributions in binary form must reproduce the above 11 // copyright notice, this list of conditions and the following disclaimer 12 // in the documentation and/or other materials provided with the 13 // distribution. 14 // * Neither the name of Google Inc. nor the names of its 15 // contributors may be used to endorse or promote products derived from 16 // this software without specific prior written permission. 17 // 18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 30 // Override mmap/munmap/mremap/sbrk to provide support for calling the 31 // related hooks (in addition, of course, to doing what these 32 // functions normally do). 33 34 #ifndef __FreeBSD__ 35 # error Should only be including malloc_hook_mmap_freebsd.h on FreeBSD systems. 36 #endif 37 38 #include <unistd.h> 39 #include <sys/syscall.h> 40 #include <sys/mman.h> 41 #include <errno.h> 42 43 // Make sure mmap doesn't get #define'd away by <sys/mman.h> 44 #undef mmap 45 46 // According to the FreeBSD documentation, use syscall if you do not 47 // need 64-bit alignment otherwise use __syscall. Indeed, syscall 48 // doesn't work correctly in most situations on 64-bit. It's return 49 // type is 'int' so for things like SYS_mmap, it actually truncates 50 // the returned address to 32-bits. 51 #if defined(__amd64__) || defined(__x86_64__) 52 # define MALLOC_HOOK_SYSCALL __syscall 53 #else 54 # define MALLOC_HOOK_SYSCALL syscall 55 #endif 56 57 58 extern "C" { 59 void* mmap(void *start, size_t length,int prot, int flags, 60 int fd, off_t offset) __THROW 61 ATTRIBUTE_SECTION(malloc_hook); 62 int munmap(void* start, size_t length) __THROW 63 ATTRIBUTE_SECTION(malloc_hook); 64 void* sbrk(intptr_t increment) __THROW 65 ATTRIBUTE_SECTION(malloc_hook); 66 } 67 68 static inline void* do_mmap(void *start, size_t length, 69 int prot, int flags, 70 int fd, off_t offset) __THROW { 71 return (void *)MALLOC_HOOK_SYSCALL(SYS_mmap, 72 start, length, prot, flags, fd, offset); 73 } 74 75 static inline void* do_sbrk(intptr_t increment) { 76 void* curbrk = 0; 77 78 #if defined(__x86_64__) || defined(__amd64__) 79 # ifdef PIC 80 __asm__ __volatile__( 81 "movq .curbrk@GOTPCREL(%%rip), %%rdx;" 82 "movq (%%rdx), %%rax;" 83 "movq %%rax, %0;" 84 : "=r" (curbrk) 85 :: "%rdx", "%rax"); 86 # else 87 __asm__ __volatile__( 88 "movq .curbrk(%%rip), %%rax;" 89 "movq %%rax, %0;" 90 : "=r" (curbrk) 91 :: "%rax"); 92 # endif 93 #else 94 __asm__ __volatile__( 95 "movl .curbrk, %%eax;" 96 "movl %%eax, %0;" 97 : "=r" (curbrk) 98 :: "%eax"); 99 #endif 100 101 if (increment == 0) { 102 return curbrk; 103 } 104 105 char* prevbrk = static_cast<char*>(curbrk); 106 void* newbrk = prevbrk + increment; 107 108 if (brk(newbrk) == -1) { 109 return reinterpret_cast<void*>(static_cast<intptr_t>(-1)); 110 } 111 112 return prevbrk; 113 } 114 115 116 extern "C" void* mmap(void *start, size_t length, int prot, int flags, 117 int fd, off_t offset) __THROW { 118 MallocHook::InvokePreMmapHook(start, length, prot, flags, fd, offset); 119 void *result; 120 if (!MallocHook::InvokeMmapReplacement( 121 start, length, prot, flags, fd, offset, &result)) { 122 result = do_mmap(start, length, prot, flags, fd, 123 static_cast<size_t>(offset)); // avoid sign extension 124 } 125 MallocHook::InvokeMmapHook(result, start, length, prot, flags, fd, offset); 126 return result; 127 } 128 129 extern "C" int munmap(void* start, size_t length) __THROW { 130 MallocHook::InvokeMunmapHook(start, length); 131 int result; 132 if (!MallocHook::InvokeMunmapReplacement(start, length, &result)) { 133 result = MALLOC_HOOK_SYSCALL(SYS_munmap, start, length); 134 } 135 136 return result; 137 } 138 139 extern "C" void* sbrk(intptr_t increment) __THROW { 140 MallocHook::InvokePreSbrkHook(increment); 141 void *result = do_sbrk(increment); 142 MallocHook::InvokeSbrkHook(result, increment); 143 return result; 144 } 145 146 /*static*/void* MallocHook::UnhookedMMap(void *start, size_t length, int prot, 147 int flags, int fd, off_t offset) { 148 void* result; 149 if (!MallocHook::InvokeMmapReplacement( 150 start, length, prot, flags, fd, offset, &result)) { 151 result = do_mmap(start, length, prot, flags, fd, offset); 152 } 153 154 return result; 155 } 156 157 /*static*/int MallocHook::UnhookedMUnmap(void *start, size_t length) { 158 int result; 159 if (!MallocHook::InvokeMunmapReplacement(start, length, &result)) { 160 result = MALLOC_HOOK_SYSCALL(SYS_munmap, start, length); 161 } 162 return result; 163 } 164 165 #undef MALLOC_HOOK_SYSCALL 166
