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1/* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
2 *
3 * Copyright (c) 2004-2011 Apple Inc. All rights reserved.
4 *
5 * @APPLE_LICENSE_HEADER_START@
6 *
7 * This file contains Original Code and/or Modifications of Original Code
8 * as defined in and that are subject to the Apple Public Source License
9 * Version 2.0 (the 'License'). You may not use this file except in
10 * compliance with the License. Please obtain a copy of the License at
11 * http://www.opensource.apple.com/apsl/ and read it before using this
12 * file.
13 *
14 * The Original Code and all software distributed under the License are
15 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
16 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
17 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
19 * Please see the License for the specific language governing rights and
20 * limitations under the License.
21 *
22 * @APPLE_LICENSE_HEADER_END@
23 */
24
25#include <stdlib.h>
26#include <string.h>
27#include <mach-o/loader.h>
28#include <unistd.h>
29#include <stdio.h>
30#include <stdbool.h>
31#include <stdarg.h>
32#include <pthread.h>
33#include <Availability.h>
34#include <mach-o/dyld_priv.h>
35
36#include "dyldLibSystemInterface.h"
37
38
39extern void _ZN4dyld3logEPKcz(const char*, ...);
40extern struct LibSystemHelpers* _ZN4dyld17gLibSystemHelpersE;
41
42
43#if __LP64__
44 #define LC_SEGMENT_COMMAND LC_SEGMENT_64
45 #define macho_header mach_header_64
46 #define macho_segment_command segment_command_64
47 #define macho_section section_64
48 #define getsectdatafromheader getsectdatafromheader_64
49#else
50 #define LC_SEGMENT_COMMAND LC_SEGMENT
51 #define macho_header mach_header
52 #define macho_segment_command segment_command
53 #define macho_section section
54#endif
55
56
57//
58// The standard versions of __cxa_get_globals*() from libstdc++-static.a cannot be used.
59// On Mac OS X, they use keymgr which dyld does not implement.
60// On iPhoneOS, they use pthread_key_create which dyld cannot use.
61//
62// Implement these ourselves to make upcalls into libSystem to malloc and create a pthread key
63//
64static pthread_key_t sCxaKey = 0;
65static char sPreMainCxaGlobals[2*sizeof(long)];
66
67// called by libstdc++.a
68char* __cxa_get_globals()
69{
70 // if libSystem.dylib not yet initialized, or is old libSystem, use shared global
71 if ( (_ZN4dyld17gLibSystemHelpersE == NULL) || (_ZN4dyld17gLibSystemHelpersE->version < 7) )
72 return sPreMainCxaGlobals;
73
74 if ( sCxaKey == 0 ) {
75 // create key
76 // we don't need a lock because only one thread can be in dyld at a time
77 _ZN4dyld17gLibSystemHelpersE->pthread_key_create(&sCxaKey, &free);
78 }
79 char* data = (char*)_ZN4dyld17gLibSystemHelpersE->pthread_getspecific(sCxaKey);
80 if ( data == NULL ) {
81 long* t = (long*)calloc(2,sizeof(long));
82 data = (char*)t;
83 _ZN4dyld17gLibSystemHelpersE->pthread_setspecific(sCxaKey, data);
84 }
85 return data;
86}
87
88// called by libstdc++.a
89char* __cxa_get_globals_fast()
90{
91 // if libSystem.dylib not yet initialized, or is old libSystem, use shared global
92 if ( (_ZN4dyld17gLibSystemHelpersE == NULL) || (_ZN4dyld17gLibSystemHelpersE->version < 7) )
93 return sPreMainCxaGlobals;
94
95 return _ZN4dyld17gLibSystemHelpersE->pthread_getspecific(sCxaKey);
96}
97
98
99
100#if !__USING_SJLJ_EXCEPTIONS__
101//
102// When dyld uses zero-cost exceptions it just needs to implement
103// _dyld_find_unwind_sections to return sections inside dyld proper.
104//
105
106extern void* ehStart __asm("section$start$__TEXT$__eh_frame");
107extern void* ehEnd __asm("section$end$__TEXT$__eh_frame");
108extern void* uwStart __asm("section$start$__TEXT$__unwind_info");
109extern void* uwEnd __asm("section$end$__TEXT$__unwind_info");
110
111extern void* textStart __asm("section$start$__TEXT$__text");
112extern void* textEnd __asm("section$end$__TEXT$__text");
113
114extern void* __dso_handle;
115
116// called by libuwind code to find unwind information sections in dyld
117bool _dyld_find_unwind_sections(void* addr, struct dyld_unwind_sections* info)
118{
119 if ( ((void*)&textStart < addr) && (addr < (void*)&textEnd) ) {
120 info->mh = (struct mach_header*)&__dso_handle;
121 info->dwarf_section = &ehStart;
122 info->dwarf_section_length = ((char*)&ehEnd - (char*)&ehStart);
123 info->compact_unwind_section = &uwStart;
124 info->compact_unwind_section_length = ((char*)&uwEnd - (char*)&uwStart);
125 return true;
126 }
127 else {
128 return false;
129 }
130}
131
132#else
133//
134// When dyld uses setjump-longjump exceptions it needs to implement
135// routines to push and pop a stack of _Unwind_FunctionContext.
136//
137
138struct _Unwind_FunctionContext
139{
140 // next function in stack of handlers
141 struct _Unwind_FunctionContext* prev;
142
143};
144
145
146static pthread_key_t sThreadChainKey = 0;
147static struct _Unwind_FunctionContext* sStaticThreadChain = NULL;
148
149//
150// When libSystem's initializers are run, they call back into dyld's
151// registerThreadHelpers which creates a pthread key and calls
152// __Unwind_SjLj_SetThreadKey().
153//
154void __Unwind_SjLj_SetThreadKey(pthread_key_t key)
155{
156 sThreadChainKey = key;
157 //_ZN4dyld3logEPKcz("__Unwind_SjLj_SetThreadKey(key=%d), sStaticThreadChain=%p\n", key, sStaticThreadChain);
158 // switch static chain to be per thread
159 _ZN4dyld17gLibSystemHelpersE->pthread_setspecific(sThreadChainKey, sStaticThreadChain);
160 sStaticThreadChain = NULL;
161 //_ZN4dyld3logEPKcz("__Unwind_SjLj_SetThreadKey(key=%d), result=%d, new top=%p\n", key, result, pthread_getspecific(sThreadChainKey));
162}
163
164
165//static void printChain()
166//{
167// _ZN4dyld3logEPKcz("chain: ");
168// struct _Unwind_FunctionContext* start = sStaticThreadChain;
169// if ( sThreadChainKey != 0 ) {
170// start = (struct _Unwind_FunctionContext*)pthread_getspecific(sThreadChainKey);
171// }
172// for (struct _Unwind_FunctionContext* p = start; p != NULL; p = p->prev) {
173// _ZN4dyld3logEPKcz("%p -> ", p);
174// }
175// _ZN4dyld3logEPKcz("\n");
176//}
177
178
179struct _Unwind_FunctionContext* __Unwind_SjLj_GetTopOfFunctionStack()
180{
181 //_ZN4dyld3logEPKcz("__Unwind_SjLj_GetTopOfFunctionStack(), key=%d, ", sThreadChainKey);
182 //printChain();
183 if ( sThreadChainKey != 0 ) {
184 return (struct _Unwind_FunctionContext*)pthread_getspecific(sThreadChainKey);
185 }
186 else {
187 return sStaticThreadChain;
188 }
189}
190
191void __Unwind_SjLj_SetTopOfFunctionStack(struct _Unwind_FunctionContext* fc)
192{
193 //_ZN4dyld3logEPKcz("__Unwind_SjLj_SetTopOfFunctionStack(%p), key=%d, prev=%p\n",
194 // fc, sThreadChainKey, (fc != NULL) ? fc->prev : NULL);
195 if ( sThreadChainKey != 0 )
196 _ZN4dyld17gLibSystemHelpersE->pthread_setspecific(sThreadChainKey, fc);
197 else
198 sStaticThreadChain = fc;
199 //_ZN4dyld3logEPKcz("__Unwind_SjLj_SetTopOfFunctionStack(%p), key=%d, ", fc, sThreadChainKey);
200 //printChain();
201}
202
203#endif
204
205
206