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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 | |
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