src/dyldExceptions.c

   1 /* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
   2  *
   3  * Copyright (c) 2004-2005 Apple Computer, Inc. All rights reserved.
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   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,
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  19  * Please see the License for the specific language governing rights and
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  24
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <mach-o/loader.h>
  28 #include <unistd.h>
  29
  30 //
  31 // BEGIN copy of code from libgcc.a source file unwind-dw2-fde-darwin.c
  32 //
  33 #define KEYMGR_API_MAJOR_GCC3           3
  34 /* ... with these keys.  */
  35 #define KEYMGR_GCC3_LIVE_IMAGE_LIST     301     /* loaded images  */
  36 #define KEYMGR_GCC3_DW2_OBJ_LIST        302     /* Dwarf2 object list  */
  37 #define KEYMGR_EH_GLOBALS_KEY           13
  38
  39 /* Node of KEYMGR_GCC3_LIVE_IMAGE_LIST.  Info about each resident image.  */
  40 struct live_images {
  41   unsigned long this_size;                      /* sizeof (live_images)  */
  42   struct mach_header *mh;                       /* the image info  */
  43   unsigned long vm_slide;
  44   void (*destructor)(struct live_images *);     /* destructor for this  */
  45   struct live_images *next;
  46   unsigned int examined_p;
  47   void *fde;
  48   void *object_info;
  49   unsigned long info[2];                        /* Future use.  */
  50 };
  51 //
  52 // END copy of code from libgcc.a source file unwind-dw2-fde-darwin.c
  53 //
  54
  55
  56 //
  57 // dyld is built as stand alone executable with a static copy of libc, libstdc++, and libgcc.
  58 //
  59 // In order for C++ exceptions to work within dyld, the C++ exception handling code
  60 // must be able to find the exception handling frame data inside dyld.  The standard
  61 // exception handling code uses crt and keymgr to keep track of all images and calls
  62 // getsectdatafromheader("__eh_frame") to find the EH data for each image. We implement
  63 // our own copy of those functions below to enable exceptions within dyld.
  64 //
  65 // Note: This exception handling is completely separate from any user code exception .
  66 //               handling which has its own keymgr (in libSystem).
  67 //
  68
  69
  70 static struct live_images   sDyldImage;  // zero filled
  71 static void*                            sObjectList = NULL;
  72 #if defined(__GNUC__) && (((__GNUC__ == 3) && (__GNUC_MINOR__ >= 5)) || (__GNUC__ >= 4))
  73 static void*                            sEHGlobals = NULL;
  74 #endif
  75
  76
  77 // called by dyldStartup.s very early
  78 void dyld_exceptions_init(struct mach_header *mh, uintptr_t slide)
  79 {
  80         sDyldImage.this_size = sizeof(struct live_images);
  81         sDyldImage.mh = mh;
  82         sDyldImage.vm_slide = slide;
  83 }
  84
  85
  86
  87 //  Hack for gcc 3.5's use of keymgr includes accessing __keymgr_global
  88 #if defined(__GNUC__) && (((__GNUC__ == 3) && (__GNUC_MINOR__ >= 5)) || (__GNUC__ >= 4))
  89 typedef struct Sinfo_Node {
  90   uint32_t size;                /* Size of this node.  */
  91   uint16_t major_version; /* API major version.  */
  92   uint16_t minor_version;       /* API minor version.  */
  93 } Tinfo_Node;
  94 static const Tinfo_Node keymgr_info = { sizeof (Tinfo_Node), KEYMGR_API_MAJOR_GCC3, 0 };
  95 const Tinfo_Node* __keymgr_global[3] = { NULL, NULL, &keymgr_info };
  96 #endif
  97
  98 static __attribute__((noreturn))
  99 void dyld_abort()
 100 {
 101         //dyld::log("internal dyld error\n");
 102         _exit(1);
 103 }
 104
 105 void* _keymgr_get_and_lock_processwide_ptr(unsigned int key)
 106 {
 107         // The C++ exception handling code uses two keys. No other keys should be seen
 108         if ( key == KEYMGR_GCC3_LIVE_IMAGE_LIST ) {
 109                 return &sDyldImage;
 110         }
 111         else if ( key == KEYMGR_GCC3_DW2_OBJ_LIST ) {
 112                 return sObjectList;
 113         }
 114         dyld_abort();
 115 }
 116
 117 void _keymgr_set_and_unlock_processwide_ptr(unsigned int key, void* value)
 118 {
 119         // The C++ exception handling code uses just this key. No other keys should be seen
 120         if ( key == KEYMGR_GCC3_DW2_OBJ_LIST ) {
 121                 sObjectList = value;
 122                 return;
 123         }
 124         dyld_abort();
 125 }
 126
 127 void _keymgr_unlock_processwide_ptr(unsigned int key)
 128 {
 129         // The C++ exception handling code uses just this key. No other keys should be seen
 130         if ( key == KEYMGR_GCC3_LIVE_IMAGE_LIST ) {
 131                 return;
 132         }
 133         dyld_abort();
 134 }
 135
 136 void* _keymgr_get_per_thread_data(unsigned int key)
 137 {
 138 #if defined(__GNUC__) && (((__GNUC__ == 3) && (__GNUC_MINOR__ >= 5)) || (__GNUC__ >= 4))
 139         // gcc 3.5 and later use this key
 140         if ( key == KEYMGR_EH_GLOBALS_KEY )
 141                 return sEHGlobals;
 142 #endif
 143
 144         // used by std::termination which dyld does not use
 145         dyld_abort();
 146 }
 147
 148 void _keymgr_set_per_thread_data(unsigned int key, void *keydata)
 149 {
 150 #if defined(__GNUC__) && (((__GNUC__ == 3) && (__GNUC_MINOR__ >= 5)) || (__GNUC__ >= 4))
 151         // gcc 3.5 and later use this key
 152         if ( key == KEYMGR_EH_GLOBALS_KEY ) {
 153                 sEHGlobals = keydata;
 154                 return;
 155         }
 156 #endif
 157         // used by std::termination which dyld does not use
 158         dyld_abort();
 159 }
 160
 161 #if __LP64__
 162         #define LC_SEGMENT_COMMAND              LC_SEGMENT_64
 163         #define macho_header                    mach_header_64
 164         #define macho_segment_command   segment_command_64
 165         #define macho_section                   section_64
 166         #define getsectdatafromheader   getsectdatafromheader_64
 167 #else
 168         #define LC_SEGMENT_COMMAND              LC_SEGMENT
 169         #define macho_header                    mach_header
 170         #define macho_segment_command   segment_command
 171         #define macho_section                   section
 172 #endif
 173
 174 // needed by C++ exception handling code to find __eh_frame section
 175 const void* getsectdatafromheader(struct mach_header* mh, const char* segname, const char* sectname, unsigned long* size)
 176 {
 177         const struct load_command* cmd;
 178         unsigned long i;
 179
 180         cmd = (struct load_command*) ((char *)mh + sizeof(struct macho_header));
 181         for(i = 0; i < mh->ncmds; i++) {
 182             if ( cmd->cmd == LC_SEGMENT_COMMAND ) {
 183                         const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
 184                         if ( strcmp(seg->segname, segname) == 0 ) {
 185                                 const struct macho_section* sect = (struct macho_section*)( (char*)seg + sizeof(struct macho_segment_command) );
 186                                 unsigned long j;
 187                                 for (j = 0; j < seg->nsects; j++) {
 188                                         if ( strcmp(sect[j].sectname, sectname) == 0 ) {
 189                                                 *size = sect[j].size;
 190                                                 return (void*)(sect[j].addr);
 191                                         }
 192                                 }
 193                     }
 194                 }
 195             cmd = (struct load_command*)( (char*)cmd + cmd->cmdsize );
 196         }
 197         return NULL;
 198 }
 199
 200
 201 // Hack for transition of rdar://problem/3933738
 202 // Can be removed later.
 203 // Allow C++ runtime to call getsectdatafromheader or getsectdatafromheader_64
 204 #if __LP64__
 205         #undef getsectdatafromheader
 206         const void* getsectdatafromheader(struct mach_header* mh, const char* segname, const char* sectname, unsigned long* size)
 207         {
 208                 return getsectdatafromheader_64(mh, segname, sectname, size);
 209         }
 210 #endif
 211
 212