launch-cache/dsc_iterator.cpp

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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 namespace dyld {
  39
  40
  41         // convert an address in the shared region where the cache would normally be mapped, into an address where the cache is currently mapped
  42         template <typename E>
  43         const uint8_t* mappedAddress(const uint8_t* cache, const uint8_t* cacheEnd, uint64_t addr)
  44         {
  45                 const dyldCacheHeader<E>* header = (dyldCacheHeader<E>*)cache;
  46                 const dyldCacheFileMapping<E>* mappings = (dyldCacheFileMapping<E>*)&cache[header->mappingOffset()];
  47                 for (uint32_t i=0; i < header->mappingCount(); ++i) {
  48                         if ( (mappings[i].address() <= addr) &&  (addr < (mappings[i].address() + mappings[i].size())) ) {
  49                                 uint64_t cacheOffset = mappings[i].file_offset() + addr - mappings[i].address();
  50                                 const uint8_t* result =  &cache[cacheOffset];
  51                                 if ( result < cacheEnd )
  52                                         return result;
  53                                 else
  54                                         return NULL;
  55                         }
  56                 }
  57                 return NULL;
  58         }
  59
  60         // call the callback block on each segment in this image
  61         template <typename A>
  62         int walkSegments(const uint8_t* cache, const uint8_t* cacheEnd, const uint8_t* firstSeg, const char* dylibPath, uint64_t inode,uint64_t modTime, const uint8_t* machHeader,
  63                                                                                         void (^callback)(const dyld_shared_cache_dylib_info* dylibInfo, const dyld_shared_cache_segment_info* segInfo))
  64         {
  65                 typedef typename A::P           P;
  66                 typedef typename A::P::E        E;
  67                 dyld_shared_cache_dylib_info    dylibInfo;
  68                 dyld_shared_cache_segment_info  segInfo;
  69                 dylibInfo.version = 2;
  70                 dylibInfo.isAlias = (dylibPath < (char*)firstSeg); // paths for aliases are store between cache header and first segment
  71                 dylibInfo.machHeader = machHeader;
  72                 dylibInfo.path = dylibPath;
  73                 dylibInfo.inode = inode;
  74                 dylibInfo.modTime = modTime;
  75                 const macho_header<P>* mh = (const macho_header<P>*)machHeader;
  76                 const macho_load_command<P>* const cmds = (macho_load_command<P>*)(machHeader + sizeof(macho_header<P>));
  77                 if ( (machHeader+ mh->sizeofcmds()) > cacheEnd )
  78                         return -1;
  79                 const uint32_t cmd_count = mh->ncmds();
  80                 const macho_load_command<P>* cmd = cmds;
  81                 // scan for LC_UUID
  82                 dylibInfo.uuid = NULL;
  83                 for (uint32_t i = 0; i < cmd_count; ++i) {
  84                         if ( cmd->cmd() == LC_UUID ) {
  85                                 const uuid_command* uc = (const uuid_command*)cmd;
  86                                 dylibInfo.uuid = &uc->uuid;
  87                                 break;
  88                         }
  89                         cmd = (const macho_load_command<P>*)(((uint8_t*)cmd)+cmd->cmdsize());
  90                 }
  91                 // callback for each LC_SEGMENT
  92                 cmd = cmds;
  93                 for (uint32_t i = 0; i < cmd_count; ++i) {
  94                         if ( cmd->cmd() == macho_segment_command<P>::CMD ) {
  95                                 macho_segment_command<P>* segCmd = (macho_segment_command<P>*)cmd;
  96                                 uint64_t fileOffset = segCmd->fileoff();
  97                                 // work around until <rdar://problem/7022345> is fixed
  98                                 if ( fileOffset == 0 ) {
  99                                         fileOffset = (machHeader - cache);
 100                                 }
 101                                 uint64_t sizem = segCmd->vmsize();
 102                                 if ( strcmp(segCmd->segname(), "__LINKEDIT") == 0 ) {
 103                                         // clip LINKEDIT size if bigger than cache file
 104                                         if ( (fileOffset+sizem) > (uint64_t)(cacheEnd-cache) )
 105                                                 sizem = (cacheEnd-cache)-fileOffset;
 106                                 }
 107                                 segInfo.version = 1;
 108                                 segInfo.name = segCmd->segname();
 109                                 segInfo.fileOffset = fileOffset;
 110                                 segInfo.fileSize = sizem;
 111                                 if ( segCmd->filesize() > segCmd->vmsize() )
 112                                         return -1;
 113                                 segInfo.address = segCmd->vmaddr();
 114                                 callback(&dylibInfo, &segInfo);
 115                         }
 116                         cmd = (const macho_load_command<P>*)(((uint8_t*)cmd)+cmd->cmdsize());
 117                 }
 118                 return 0;
 119         }
 120
 121
 122         // call walkSegments on each image in the cache
 123         template <typename A>
 124         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))
 125         {
 126                 // Sanity check there is at least a header
 127                 if ( (size > 0) && (size < 0x7000) )
 128                         return -1;
 129                 typedef typename A::P::E                        E;
 130                 typedef typename A::P                           P;
 131                 const dyldCacheHeader<E>*      header   = (dyldCacheHeader<E>*)cache;
 132                 const dyldCacheImageInfo<E>*   dylibs   = (dyldCacheImageInfo<E>*)&cache[header->imagesOffset()];
 133                 const dyldCacheFileMapping<E>* mappings = (dyldCacheFileMapping<E>*)&cache[header->mappingOffset()];
 134                 uint64_t greatestMappingOffset = 0;
 135                 for (uint32_t i=0; i < header->mappingCount(); ++i) {
 136                         if ( (size != 0) && (mappings[i].file_offset() > size) )
 137                                 return -1;
 138                         uint64_t endOffset = mappings[i].file_offset()+mappings[i].size();
 139                         if ( (size != 0) && (endOffset > size) )
 140                                 return -1;
 141                         if ( endOffset > greatestMappingOffset )
 142                                 greatestMappingOffset = endOffset;
 143                 }
 144                 const uint8_t* cacheEnd = &cache[size];
 145                 if ( size == 0 ) {
 146                         // Zero size means old API is being used, assume all mapped
 147                         cacheEnd = &cache[greatestMappingOffset];
 148                 }
 149                 else {
 150                         // verifiy mappings are not bigger than size
 151                         if ( size < greatestMappingOffset )
 152                                 return -1;
 153                 }
 154                 // verify all image infos are mapped
 155                 if ( (const uint8_t*)&dylibs[header->imagesCount()] > cacheEnd )
 156                         return -1;
 157                 const uint8_t* firstSeg = NULL;
 158                 for (uint32_t i=0; i < header->imagesCount(); ++i) {
 159                         const char* dylibPath  = (char*)cache + dylibs[i].pathFileOffset();
 160                         uint64_t inode = dylibs[i].inode();
 161                         uint64_t modTime = dylibs[i].modTime();
 162                         if ( (const uint8_t*)dylibPath > cacheEnd )
 163                                 return -1;
 164                         const uint8_t* machHeader = mappedAddress<E>(cache, cacheEnd, dylibs[i].address());
 165                         if ( machHeader == NULL )
 166                                 return -1;
 167                         if ( machHeader > cacheEnd )
 168                                 return -1;
 169                         if ( firstSeg == NULL )
 170                                 firstSeg = machHeader;
 171                         int result = walkSegments<A>(cache, cacheEnd, firstSeg, dylibPath, inode, modTime, machHeader, callback);
 172                         if ( result != 0 )
 173                                 return result;
 174                 }
 175                 return 0;
 176         }
 177
 178 }
 179
 180
 181 // Given a pointer to an in-memory copy of a dyld shared cache file,
 182 // this routine will call the callback block once for each segment
 183 // in each dylib in the shared cache file.
 184 // Returns -1 if there was an error, otherwise 0.
 185 extern int dyld_shared_cache_iterate(const void* shared_cache_file, uint32_t shared_cache_size,
 186                                                                         void (^callback)(const dyld_shared_cache_dylib_info* dylibInfo, const dyld_shared_cache_segment_info* segInfo)) {
 187         const uint8_t* cache = (uint8_t*)shared_cache_file;
 188                  if ( strcmp((char*)cache, "dyld_v1    i386") == 0 )
 189                         return dyld::walkImages<x86>(cache, shared_cache_size, callback);
 190         else if ( strcmp((char*)cache, "dyld_v1  x86_64") == 0 )
 191                         return dyld::walkImages<x86_64>(cache, shared_cache_size, callback);
 192         else if ( strcmp((char*)cache, "dyld_v1 x86_64h") == 0 )
 193                         return dyld::walkImages<x86_64>(cache, shared_cache_size, callback);
 194         else if ( strcmp((char*)cache, "dyld_v1   armv5") == 0 )
 195                         return dyld::walkImages<arm>(cache, shared_cache_size, callback);
 196         else if ( strcmp((char*)cache, "dyld_v1   armv6") == 0 )
 197                         return dyld::walkImages<arm>(cache, shared_cache_size, callback);
 198         else if ( strcmp((char*)cache, "dyld_v1   armv7") == 0 )
 199                         return dyld::walkImages<arm>(cache, shared_cache_size, callback);
 200         else if ( strncmp((char*)cache, "dyld_v1  armv7", 14) == 0 )
 201                         return dyld::walkImages<arm>(cache, shared_cache_size, callback);
 202         else if ( strcmp((char*)cache, "dyld_v1   arm64") == 0 )
 203                         return dyld::walkImages<arm64>(cache, shared_cache_size, callback);
 204         else
 205                 return -1;
 206 }
 207
 208
 209 // implement old version by calling new version
 210 int dyld_shared_cache_iterate_segments_with_slide(const void* shared_cache_file, dyld_shared_cache_iterator_slide_t callback)
 211 {
 212         return dyld_shared_cache_iterate(shared_cache_file, 0, ^(const dyld_shared_cache_dylib_info* dylibInfo, const dyld_shared_cache_segment_info* segInfo) {
 213                                                                                                                 callback(dylibInfo->path, segInfo->name, segInfo->fileOffset, segInfo->fileSize, segInfo->address, 0);
 214         });
 215 }
 216
 217 // implement non-block version by calling block version
 218 int dyld_shared_cache_iterate_segments_with_slide_nb(const void* shared_cache_file, dyld_shared_cache_iterator_slide_nb_t func, void* userData)
 219 {
 220         return dyld_shared_cache_iterate_segments_with_slide(shared_cache_file, ^(const char* dylibName, const char* segName,
 221                                                                                                         uint64_t offset, uint64_t size, uint64_t mappedddress, uint64_t slide) {
 222                                                                                                                 (*func)(dylibName, segName, offset, size, mappedddress, slide, userData);
 223         });
 224 }
 225
 226
 227 // implement non-slide version by wrapping slide version in block
 228 int dyld_shared_cache_iterate_segments(const void* shared_cache_file, dyld_shared_cache_iterator_t callback)
 229 {
 230         dyld_shared_cache_iterator_slide_t wrapper_cb = ^(const char* dylibName, const char* segName, uint64_t offset,
 231                                                                                                                 uint64_t size, uint64_t mappedddress, uint64_t slide) {
 232                                                                                                                 callback(dylibName, segName, offset, size, mappedddress);
 233                                                                                                         };
 234         return dyld_shared_cache_iterate_segments_with_slide(shared_cache_file, wrapper_cb);
 235 }
 236
 237 // implement non-slide,non-block version by wrapping slide version in block
 238 int dyld_shared_cache_iterate_segments_nb(const void* shared_cache_file, dyld_shared_cache_iterator_nb_t func, void* userData)
 239 {
 240         return dyld_shared_cache_iterate_segments_with_slide(shared_cache_file, ^(const char* dylibName, const char* segName,
 241                                                                                                                                                           uint64_t offset, uint64_t size, uint64_t mappedddress, uint64_t slide) {
 242                 (*func)(dylibName, segName, offset, size, mappedddress, userData);
 243         });
 244 }
 245