1 | // -*- C++ -*- |
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2 | |
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3 | /* |
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4 | |
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5 | Heap Layers: An Extensible Memory Allocation Infrastructure |
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6 | |
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7 | Copyright (C) 2000-2005 by Emery Berger |
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8 | http://www.cs.umass.edu/~emery |
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9 | emery@cs.umass.edu |
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10 | |
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11 | This program is free software; you can redistribute it and/or modify |
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12 | it under the terms of the GNU General Public License as published by |
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13 | the Free Software Foundation; either version 2 of the License, or |
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14 | (at your option) any later version. |
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15 | |
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16 | This program is distributed in the hope that it will be useful, |
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17 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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18 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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19 | GNU General Public License for more details. |
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20 | |
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21 | You should have received a copy of the GNU General Public License |
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22 | along with this program; if not, write to the Free Software |
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23 | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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24 | |
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25 | */ |
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26 | |
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27 | #ifndef _MMAPWRAPPER_H_ |
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28 | #define _MMAPWRAPPER_H_ |
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29 | |
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30 | #if defined(_WIN32) |
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31 | #include <windows.h> |
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32 | #else |
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33 | // UNIX |
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34 | #include <sys/types.h> |
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35 | #include <sys/stat.h> |
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36 | #include <fcntl.h> |
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37 | #include <unistd.h> |
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38 | #include <sys/mman.h> |
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39 | #include <map> |
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40 | #endif |
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41 | |
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42 | #if HL_EXECUTABLE_HEAP |
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43 | #define HL_MMAP_PROTECTION_MASK (PROT_READ | PROT_WRITE | PROT_EXEC) |
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44 | #else |
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45 | #define HL_MMAP_PROTECTION_MASK (PROT_READ | PROT_WRITE) |
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46 | #endif |
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47 | |
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48 | #if !defined(MAP_ANONYMOUS) && defined(MAP_ANON) |
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49 | #define MAP_ANONYMOUS MAP_ANON |
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50 | #endif |
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51 | |
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52 | namespace HL { |
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53 | |
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54 | class MmapWrapper { |
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55 | public: |
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56 | |
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57 | #if defined(_WIN32) |
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58 | |
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59 | // Microsoft Windows has 4K pages aligned to a 64K boundary. |
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60 | enum { Size = 4 * 1024 }; |
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61 | enum { Alignment = 64 * 1024 }; |
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62 | |
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63 | static void * map (size_t sz) { |
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64 | void * ptr; |
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65 | #if HL_EXECUTABLE_HEAP |
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66 | const int permflags = PAGE_EXECUTE_READWRITE; |
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67 | #else |
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68 | const int permflags = PAGE_READWRITE; |
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69 | #endif |
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70 | ptr = VirtualAlloc (NULL, sz, MEM_RESERVE | MEM_COMMIT | MEM_TOP_DOWN, permflags); |
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71 | return ptr; |
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72 | } |
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73 | |
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74 | static void unmap (void * ptr, size_t) { |
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75 | VirtualFree (ptr, 0, MEM_RELEASE); |
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76 | } |
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77 | |
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78 | #else |
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79 | |
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80 | #if defined(__SVR4) |
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81 | // Solaris aligns 8K pages to a 64K boundary. |
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82 | enum { Size = 8 * 1024 }; |
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83 | enum { Alignment = 64 * 1024 }; |
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84 | #else |
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85 | // Linux and most other operating systems align memory to a 4K boundary. |
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86 | enum { Size = 4 * 1024 }; |
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87 | enum { Alignment = 4 * 1024 }; |
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88 | #endif |
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89 | |
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90 | static void * map (size_t sz) { |
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91 | |
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92 | if (sz == 0) { |
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93 | return NULL; |
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94 | } |
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95 | |
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96 | void * ptr; |
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97 | |
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98 | #if defined(MAP_ALIGN) && defined(MAP_ANON) |
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99 | // Request memory aligned to the Alignment value above. |
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100 | ptr = mmap ((char *) Alignment, sz, HL_MMAP_PROTECTION_MASK, MAP_PRIVATE | MAP_ALIGN | MAP_ANON, -1, 0); |
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101 | #elif !defined(MAP_ANONYMOUS) |
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102 | static int fd = ::open ("/dev/zero", O_RDWR); |
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103 | ptr = mmap (NULL, sz, HL_MMAP_PROTECTION_MASK, MAP_PRIVATE, fd, 0); |
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104 | #else |
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105 | ptr = mmap (0, sz, HL_MMAP_PROTECTION_MASK, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); |
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106 | #endif |
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107 | |
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108 | if (ptr == MAP_FAILED) { |
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109 | return NULL; |
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110 | } else { |
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111 | return ptr; |
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112 | } |
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113 | } |
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114 | |
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115 | static void unmap (void * ptr, size_t sz) { |
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116 | munmap (reinterpret_cast<char *>(ptr), sz); |
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117 | } |
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118 | |
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119 | #endif |
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120 | |
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121 | }; |
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122 | |
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123 | } |
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124 | |
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125 | #endif |
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