1 /**************************************************************************
2 *
3 * Copyright (C) 1999-2005 Brian Paul All Rights Reserved.
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9 * and/or sell copies of the Software, and to permit persons to whom the
10 * Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be included
13 * in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
16 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
19 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
20 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
21 * OTHER DEALINGS IN THE SOFTWARE.
22 *
23 **************************************************************************/
24
25
26 /**
27 * \file exemem.c
28 * Functions for allocating executable memory.
29 *
30 * \author Keith Whitwell
31 */
32
33
34 #include "util/compiler.h"
35 #include "util/simple_mtx.h"
36 #include "util/u_debug.h"
37 #include "util/u_thread.h"
38 #include "util/u_memory.h"
39
40 #include "rtasm_execmem.h"
41
42 #ifndef MAP_ANONYMOUS
43 #define MAP_ANONYMOUS MAP_ANON
44 #endif
45
46 #if DETECT_OS_WINDOWS
47 #include <windows.h>
48 #endif
49
50 #if DETECT_OS_POSIX
51
52
53 /*
54 * Allocate a large block of memory which can hold code then dole it out
55 * in pieces by means of the generic memory manager code.
56 */
57
58 #include <unistd.h>
59 #include <sys/mman.h>
60 #include "util/u_mm.h"
61
62 #define EXEC_HEAP_SIZE (10*1024*1024)
63
64 static simple_mtx_t exec_mutex = SIMPLE_MTX_INITIALIZER;
65
66 static struct mem_block *exec_heap = NULL;
67 static unsigned char *exec_mem = NULL;
68
69
70 static int
init_heap(void)71 init_heap(void)
72 {
73 if (!exec_heap)
74 exec_heap = u_mmInit( 0, EXEC_HEAP_SIZE );
75
76 if (!exec_mem)
77 exec_mem = (unsigned char *) mmap(NULL, EXEC_HEAP_SIZE,
78 PROT_EXEC | PROT_READ | PROT_WRITE,
79 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
80
81 return (exec_mem != MAP_FAILED);
82 }
83
84
85 void *
rtasm_exec_malloc(size_t size)86 rtasm_exec_malloc(size_t size)
87 {
88 struct mem_block *block = NULL;
89 void *addr = NULL;
90
91 simple_mtx_lock(&exec_mutex);
92
93 if (!init_heap())
94 goto bail;
95
96 if (exec_heap) {
97 size = (size + 31) & ~31; /* next multiple of 32 bytes */
98 block = u_mmAllocMem( exec_heap, size, 5, 0 ); /* 5 -> 32-byte alignment */
99 }
100
101 if (block)
102 addr = exec_mem + block->ofs;
103 else
104 debug_printf("rtasm_exec_malloc failed\n");
105
106 bail:
107 simple_mtx_unlock(&exec_mutex);
108
109 return addr;
110 }
111
112
113 void
rtasm_exec_free(void * addr)114 rtasm_exec_free(void *addr)
115 {
116 simple_mtx_lock(&exec_mutex);
117
118 if (exec_heap) {
119 struct mem_block *block = u_mmFindBlock(exec_heap, (unsigned char *)addr - exec_mem);
120
121 if (block)
122 u_mmFreeMem(block);
123 }
124
125 simple_mtx_unlock(&exec_mutex);
126 }
127
128
129 #elif DETECT_OS_WINDOWS
130
131
132 /*
133 * Avoid Data Execution Prevention.
134 */
135
136 void *
rtasm_exec_malloc(size_t size)137 rtasm_exec_malloc(size_t size)
138 {
139 return VirtualAlloc(NULL, size, MEM_COMMIT, PAGE_EXECUTE_READWRITE);
140 }
141
142
143 void
rtasm_exec_free(void * addr)144 rtasm_exec_free(void *addr)
145 {
146 VirtualFree(addr, 0, MEM_RELEASE);
147 }
148
149
150 #else
151
152
153 /*
154 * Just use regular memory.
155 */
156
157 void *
rtasm_exec_malloc(size_t size)158 rtasm_exec_malloc(size_t size)
159 {
160 return MALLOC( size );
161 }
162
163
164 void
rtasm_exec_free(void * addr)165 rtasm_exec_free(void *addr)
166 {
167 FREE(addr);
168 }
169
170
171 #endif
172