launch-cache/dsc_iterator.cpp

   1 /* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
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   3  * Copyright (c) 2009-2012 Apple Inc. All rights reserved.
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  24
  25 #include <stdlib.h>
  26 #include <stdio.h>
  27 #include <Availability.h>
  28
  29
  30 #include "dsc_iterator.h"
  31 #include "dyld_cache_format.h"
  32 #define NO_ULEB
  33 #include "Architectures.hpp"
  34 #include "MachOFileAbstraction.hpp"
  35 #include "CacheFileAbstraction.hpp"
  36
  37
  38
  39 namespace dyld {
  40
  41
  42         // convert an address in the shared region where the cache would normally be mapped, into an address where the cache is currently mapped
  43         template <typename E>
  44         const uint8_t* mappedAddress(const uint8_t* cache, const uint8_t* cacheEnd, uint64_t addr)
  45         {
  46                 const dyldCacheHeader<E>* header = (dyldCacheHeader<E>*)cache;
  47                 const dyldCacheFileMapping<E>* mappings = (dyldCacheFileMapping<E>*)&cache[header->mappingOffset()];
  48                 for (uint32_t i=0; i < header->mappingCount(); ++i) {
  49                         if ( (mappings[i].address() <= addr) &&  (addr < (mappings[i].address() + mappings[i].size())) ) {
  50                                 uint32_t cacheOffset = mappings[i].file_offset() + addr - mappings[i].address();
  51                                 const uint8_t* result =  &cache[cacheOffset];
  52                                 if ( result < cacheEnd )
  53                                         return result;
  54                                 else
  55                                         return NULL;
  56                         }
  57                 }
  58                 return NULL;
  59         }
  60
  61         // call the callback block on each segment in this image
  62         template <typename A>
  63         int walkSegments(const uint8_t* cache, const uint8_t* cacheEnd, const uint8_t* firstSeg, const char* dylibPath, const uint8_t* machHeader,
  64                                                                                         void (^callback)(const dyld_shared_cache_dylib_info* dylibInfo, const dyld_shared_cache_segment_info* segInfo))
  65         {
  66                 typedef typename A::P           P;
  67                 typedef typename A::P::E        E;
  68                 dyld_shared_cache_dylib_info    dylibInfo;
  69                 dyld_shared_cache_segment_info  segInfo;
  70                 dylibInfo.version = 1;
  71                 dylibInfo.isAlias = (dylibPath < (char*)firstSeg); // paths for aliases are store between cache header and first segment
  72                 dylibInfo.machHeader = machHeader;
  73                 dylibInfo.path = dylibPath;
  74                 const macho_header<P>* mh = (const macho_header<P>*)machHeader;
  75                 const macho_load_command<P>* const cmds = (macho_load_command<P>*)(machHeader + sizeof(macho_header<P>));
  76                 if ( (machHeader+ mh->sizeofcmds()) > cacheEnd )
  77                         return -1;
  78                 const uint32_t cmd_count = mh->ncmds();
  79                 const macho_load_command<P>* cmd = cmds;
  80                 // scan for LC_UUID
  81                 dylibInfo.uuid = NULL;
  82                 for (uint32_t i = 0; i < cmd_count; ++i) {
  83                         if ( cmd->cmd() == LC_UUID ) {
  84                                 const uuid_command* uc = (const uuid_command*)cmd;
  85                                 dylibInfo.uuid = &uc->uuid;
  86                                 break;
  87                         }
  88                         cmd = (const macho_load_command<P>*)(((uint8_t*)cmd)+cmd->cmdsize());
  89                 }
  90                 // callback for each LC_SEGMENT
  91                 cmd = cmds;
  92                 for (uint32_t i = 0; i < cmd_count; ++i) {
  93                         if ( cmd->cmd() == macho_segment_command<P>::CMD ) {
  94                                 macho_segment_command<P>* segCmd = (macho_segment_command<P>*)cmd;
  95                                 uint64_t fileOffset = segCmd->fileoff();
  96                                 // work around until <rdar://problem/7022345> is fixed
  97                                 if ( fileOffset == 0 ) {
  98                                         fileOffset = (machHeader - cache);
  99                                 }
 100                                 uint64_t sizem = segCmd->vmsize();
 101                                 if ( strcmp(segCmd->segname(), "__LINKEDIT") == 0 ) {
 102                                         // clip LINKEDIT size if bigger than cache file
 103                                         if ( (fileOffset+sizem) > (uint64_t)(cacheEnd-cache) )
 104                                                 sizem = (cacheEnd-cache)-fileOffset;
 105                                 }
 106                                 segInfo.version = 1;
 107                                 segInfo.name = segCmd->segname();
 108                                 segInfo.fileOffset = fileOffset;
 109                                 segInfo.fileSize = sizem;
 110                                 segInfo.address = segCmd->vmaddr();
 111                                 callback(&dylibInfo, &segInfo);
 112                         }
 113                         cmd = (const macho_load_command<P>*)(((uint8_t*)cmd)+cmd->cmdsize());
 114                 }
 115                 return 0;
 116         }
 117
 118
 119         // call walkSegments on each image in the cache
 120         template <typename A>
 121         int walkImages(const uint8_t* cache, uint32_t size,     void (^callback)(const dyld_shared_cache_dylib_info* dylibInfo, const dyld_shared_cache_segment_info* segInfo))
 122         {
 123                 // Sanity check there is at least a header
 124                 if ( (size > 0) && (size < 0x7000) )
 125                         return -1;
 126                 typedef typename A::P::E                        E;
 127                 typedef typename A::P                           P;
 128                 const dyldCacheHeader<E>*      header   = (dyldCacheHeader<E>*)cache;
 129                 const dyldCacheImageInfo<E>*   dylibs   = (dyldCacheImageInfo<E>*)&cache[header->imagesOffset()];
 130                 const dyldCacheFileMapping<E>* mappings = (dyldCacheFileMapping<E>*)&cache[header->mappingOffset()];
 131                 uint64_t greatestMappingOffset = 0;
 132                 for (uint32_t i=0; i < header->mappingCount(); ++i) {
 133                         if ( (size != 0) && (mappings[i].file_offset() > size) )
 134                                 return -1;
 135                         uint64_t endOffset = mappings[i].file_offset()+mappings[i].size();
 136                         if ( (size != 0) && (endOffset > size) )
 137                                 return -1;
 138                         if ( endOffset > greatestMappingOffset )
 139                                 greatestMappingOffset = endOffset;
 140                 }
 141                 const uint8_t* cacheEnd = &cache[size];
 142                 if ( size == 0 ) {
 143                         // Zero size means old API is being used, assume all mapped
 144                         cacheEnd = &cache[greatestMappingOffset];
 145                 }
 146                 else {
 147                         // verifiy mappings are not bigger than size
 148                         if ( size < greatestMappingOffset )
 149                                 return -1;
 150                 }
 151                 // verify all image infos are mapped
 152                 if ( (const uint8_t*)&dylibs[header->imagesCount()] > cacheEnd )
 153                         return -1;
 154                 const uint8_t* firstSeg = NULL;
 155                 for (uint32_t i=0; i < header->imagesCount(); ++i) {
 156                         const char* dylibPath  = (char*)cache + dylibs[i].pathFileOffset();
 157                         if ( (const uint8_t*)dylibPath > cacheEnd )
 158                                 return -1;
 159                         const uint8_t* machHeader = mappedAddress<E>(cache, cacheEnd, dylibs[i].address());
 160                         if ( machHeader == NULL )
 161                                 return -1;
 162                         if ( machHeader > cacheEnd )
 163                                 return -1;
 164                         if ( firstSeg == NULL )
 165                                 firstSeg = machHeader;
 166                         int result = walkSegments<A>(cache, cacheEnd, firstSeg, dylibPath, machHeader, callback);
 167                         if ( result != 0 )
 168                                 return result;
 169                 }
 170                 return 0;
 171         }
 172
 173 }
 174
 175
 176 // Given a pointer to an in-memory copy of a dyld shared cache file,
 177 // this routine will call the callback block once for each segment
 178 // in each dylib in the shared cache file.
 179 // Returns -1 if there was an error, otherwise 0.
 180 extern int dyld_shared_cache_iterate(const void* shared_cache_file, uint32_t shared_cache_size,
 181                                                                         void (^callback)(const dyld_shared_cache_dylib_info* dylibInfo, const dyld_shared_cache_segment_info* segInfo)) {
 182         const uint8_t* cache = (uint8_t*)shared_cache_file;
 183                  if ( strcmp((char*)cache, "dyld_v1    i386") == 0 )
 184                         return dyld::walkImages<x86>(cache, shared_cache_size, callback);
 185         else if ( strcmp((char*)cache, "dyld_v1  x86_64") == 0 )
 186                         return dyld::walkImages<x86_64>(cache, shared_cache_size, callback);
 187         else if ( strcmp((char*)cache, "dyld_v1   armv5") == 0 )
 188                         return dyld::walkImages<arm>(cache, shared_cache_size, callback);
 189         else if ( strcmp((char*)cache, "dyld_v1   armv6") == 0 )
 190                         return dyld::walkImages<arm>(cache, shared_cache_size, callback);
 191         else if ( strcmp((char*)cache, "dyld_v1   armv7") == 0 )
 192                         return dyld::walkImages<arm>(cache, shared_cache_size, callback);
 193         else if ( strncmp((char*)cache, "dyld_v1  armv7", 14) == 0 )
 194                         return dyld::walkImages<arm>(cache, shared_cache_size, callback);
 195         else
 196                 return -1;
 197 }
 198
 199
 200 // implement old version by calling new version
 201 int dyld_shared_cache_iterate_segments_with_slide(const void* shared_cache_file, dyld_shared_cache_iterator_slide_t callback)
 202 {
 203         return dyld_shared_cache_iterate(shared_cache_file, 0, ^(const dyld_shared_cache_dylib_info* dylibInfo, const dyld_shared_cache_segment_info* segInfo) {
 204                                                                                                                 callback(dylibInfo->path, segInfo->name, segInfo->fileOffset, segInfo->fileSize, segInfo->address, 0);
 205         });
 206 }
 207
 208 // implement non-block version by calling block version
 209 int dyld_shared_cache_iterate_segments_with_slide_nb(const void* shared_cache_file, dyld_shared_cache_iterator_slide_nb_t func, void* userData)
 210 {
 211         return dyld_shared_cache_iterate_segments_with_slide(shared_cache_file, ^(const char* dylibName, const char* segName,
 212                                                                                                         uint64_t offset, uint64_t size, uint64_t mappedddress, uint64_t slide) {
 213                                                                                                                 (*func)(dylibName, segName, offset, size, mappedddress, slide, userData);
 214         });
 215 }
 216
 217
 218 // implement non-slide version by wrapping slide version in block
 219 int dyld_shared_cache_iterate_segments(const void* shared_cache_file, dyld_shared_cache_iterator_t callback)
 220 {
 221         dyld_shared_cache_iterator_slide_t wrapper_cb = ^(const char* dylibName, const char* segName, uint64_t offset,
 222                                                                                                                 uint64_t size, uint64_t mappedddress, uint64_t slide) {
 223                                                                                                                 callback(dylibName, segName, offset, size, mappedddress);
 224                                                                                                         };
 225         return dyld_shared_cache_iterate_segments_with_slide(shared_cache_file, wrapper_cb);
 226 }
 227
 228 // implement non-slide,non-block version by wrapping slide version in block
 229 int dyld_shared_cache_iterate_segments_nb(const void* shared_cache_file, dyld_shared_cache_iterator_nb_t func, void* userData)
 230 {
 231         return dyld_shared_cache_iterate_segments_with_slide(shared_cache_file, ^(const char* dylibName, const char* segName,
 232                                                                                                                                                           uint64_t offset, uint64_t size, uint64_t mappedddress, uint64_t slide) {
 233                 (*func)(dylibName, segName, offset, size, mappedddress, userData);
 234         });
 235 }
 236