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 // Copyright (c) 2007, Google Inc.

 // All rights reserved.

 //

 // Redistribution and use in source and binary forms, with or without

 // modification, are permitted provided that the following conditions are

 // met:

 //

 //     * Redistributions of source code must retain the above copyright

 // notice, this list of conditions and the following disclaimer.

 //     * Redistributions in binary form must reproduce the above

 // copyright notice, this list of conditions and the following disclaimer

 // in the documentation and/or other materials provided with the

 // distribution.

 //     * Neither the name of Google Inc. nor the names of its

 // contributors may be used to endorse or promote products derived from

 // this software without specific prior written permission.

 //

 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 #include "client/mac/handler/dynamic_images.h"

 extern "C" { // needed to compile on Leopard

   #include <mach-o/nlist.h>

   #include <stdlib.h>

   #include <stdio.h>

 }

 #include <assert.h>

 #include <AvailabilityMacros.h>

 #include <dlfcn.h>

 #include <mach/task_info.h>

 #include <sys/sysctl.h>

 #include <TargetConditionals.h>

 #include <unistd.h>

 #include <algorithm>

 #include <string>

 #include <vector>

 #include "breakpad_nlist_64.h"

 #if !TARGET_OS_IPHONE

 #include <CoreServices/CoreServices.h>

 #ifndef MAC_OS_X_VERSION_10_6

 #define MAC_OS_X_VERSION_10_6 1060

 #endif

 #if MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_6

 // Fallback declarations for TASK_DYLD_INFO and friends, introduced in

 // <mach/task_info.h> in the Mac OS X 10.6 SDK.

 #define TASK_DYLD_INFO 17

 struct task_dyld_info {

   mach_vm_address_t all_image_info_addr;

   mach_vm_size_t all_image_info_size;

 };

 typedef struct task_dyld_info task_dyld_info_data_t;

 typedef struct task_dyld_info *task_dyld_info_t;

 #define TASK_DYLD_INFO_COUNT (sizeof(task_dyld_info_data_t) / sizeof(natural_t))

 #endif

 #endif  // !TARGET_OS_IPHONE

 namespace google_breakpad {

 using std::string;

 using std::vector;

 //==============================================================================

 // Returns the size of the memory region containing |address| and the

 // number of bytes from |address| to the end of the region.

 // We potentially, will extend the size of the original

 // region by the size of the following region if it's contiguous with the

 // first in order to handle cases when we're reading strings and they

 // straddle two vm regions.

 //

 static mach_vm_size_t GetMemoryRegionSize(task_port_t target_task,

                                           const uint64_t address,

                                           mach_vm_size_t *size_to_end) {

   mach_vm_address_t region_base = (mach_vm_address_t)address;

   mach_vm_size_t region_size;

   natural_t nesting_level = 0;

   vm_region_submap_info_64 submap_info;

   mach_msg_type_number_t info_count = VM_REGION_SUBMAP_INFO_COUNT_64;

   // Get information about the vm region containing |address|

   vm_region_recurse_info_t region_info;

   region_info = reinterpret_cast<vm_region_recurse_info_t>(&submap_info);

   kern_return_t result =

     mach_vm_region_recurse(target_task,

                            &region_base,

                            &region_size,

                            &nesting_level,

                            region_info,

                            &info_count);

   if (result == KERN_SUCCESS) {

     // Get distance from |address| to the end of this region

     *size_to_end = region_base + region_size -(mach_vm_address_t)address;

     // If we want to handle strings as long as 4096 characters we may need

     // to check if there's a vm region immediately following the first one.

     // If so, we need to extend |*size_to_end| to go all the way to the end

     // of the second region.

     if (*size_to_end < 4096) {

       // Second region starts where the first one ends

       mach_vm_address_t region_base2 =

         (mach_vm_address_t)(region_base + region_size);

       mach_vm_size_t region_size2;

       // Get information about the following vm region

       result =

         mach_vm_region_recurse(target_task,

                                &region_base2,

                                &region_size2,

                                &nesting_level,

                                region_info,

                                &info_count);

       // Extend region_size to go all the way to the end of the 2nd region

       if (result == KERN_SUCCESS

           && region_base2 == region_base + region_size) {

         region_size += region_size2;

       }

     }

     *size_to_end = region_base + region_size -(mach_vm_address_t)address;

   } else {

     region_size = 0;

     *size_to_end = 0;

   }

   return region_size;

 }

 #define kMaxStringLength 8192

 //==============================================================================

 // Reads a NULL-terminated string from another task.

 //

 // Warning!  This will not read any strings longer than kMaxStringLength-1

 //

 static string ReadTaskString(task_port_t target_task,

                              const uint64_t address) {

   // The problem is we don't know how much to read until we know how long

   // the string is. And we don't know how long the string is, until we've read

   // the memory!  So, we'll try to read kMaxStringLength bytes

   // (or as many bytes as we can until we reach the end of the vm region).

   mach_vm_size_t size_to_end;

   GetMemoryRegionSize(target_task, address, &size_to_end);

   if (size_to_end > 0) {

     mach_vm_size_t size_to_read =

       size_to_end > kMaxStringLength ? kMaxStringLength : size_to_end;

     vector<uint8_t> bytes;

     if (ReadTaskMemory(target_task, address, (size_t)size_to_read, bytes) !=

         KERN_SUCCESS)

       return string();

     return string(reinterpret_cast<const char*>(&bytes[0]));

   }

   return string();

 }

 //==============================================================================

 // Reads an address range from another task. The bytes read will be returned

 // in bytes, which will be resized as necessary.

 kern_return_t ReadTaskMemory(task_port_t target_task,

                              const uint64_t address,

                              size_t length,

                              vector<uint8_t> &bytes) {

   int systemPageSize = getpagesize();

   // use the negative of the page size for the mask to find the page address

   mach_vm_address_t page_address = address & (-systemPageSize);

   mach_vm_address_t last_page_address =

       (address + length + (systemPageSize - 1)) & (-systemPageSize);

   mach_vm_size_t page_size = last_page_address - page_address;

   uint8_t* local_start;

   uint32_t local_length;

   kern_return_t r = mach_vm_read(target_task,

                                  page_address,

                                  page_size,

                                  reinterpret_cast<vm_offset_t*>(&local_start),

                                  &local_length);

   if (r != KERN_SUCCESS)

     return r;

   bytes.resize(length);

   memcpy(&bytes[0],

          &local_start[(mach_vm_address_t)address - page_address],

          length);

   mach_vm_deallocate(mach_task_self(), (uintptr_t)local_start, local_length);

   return KERN_SUCCESS;

 }

 #pragma mark -

 //==============================================================================

 // Traits structs for specializing function templates to handle

 // 32-bit/64-bit Mach-O files.

 struct MachO32 {

   typedef mach_header mach_header_type;

   typedef segment_command mach_segment_command_type;

   typedef dyld_image_info32 dyld_image_info;

   typedef dyld_all_image_infos32 dyld_all_image_infos;

   typedef struct nlist nlist_type;

   static const uint32_t magic = MH_MAGIC;

   static const uint32_t segment_load_command = LC_SEGMENT;

 };

 struct MachO64 {

   typedef mach_header_64 mach_header_type;

   typedef segment_command_64 mach_segment_command_type;

   typedef dyld_image_info64 dyld_image_info;

   typedef dyld_all_image_infos64 dyld_all_image_infos;

   typedef struct nlist_64 nlist_type;

   static const uint32_t magic = MH_MAGIC_64;

   static const uint32_t segment_load_command = LC_SEGMENT_64;

 };

 template<typename MachBits>

 bool FindTextSection(DynamicImage& image) {

   typedef typename MachBits::mach_header_type mach_header_type;

   typedef typename MachBits::mach_segment_command_type

       mach_segment_command_type;

   const mach_header_type* header =

       reinterpret_cast<const mach_header_type*>(&image.header_[0]);

   if(header->magic != MachBits::magic) {

     return false;

   }

   const struct load_command *cmd =

       reinterpret_cast<const struct load_command *>(header + 1);

   bool found_text_section = false;

   bool found_dylib_id_command = false;

   for (unsigned int i = 0; cmd && (i < header->ncmds); ++i) {

     if (!found_text_section) {

       if (cmd->cmd == MachBits::segment_load_command) {

         const mach_segment_command_type *seg =

             reinterpret_cast<const mach_segment_command_type *>(cmd);

         if (!strcmp(seg->segname, "__TEXT")) {

           image.vmaddr_ = static_cast<mach_vm_address_t>(seg->vmaddr);

           image.vmsize_ = static_cast<mach_vm_size_t>(seg->vmsize);

           image.slide_ = 0;

           if (seg->fileoff == 0 && seg->filesize != 0) {

             image.slide_ =

                 (uintptr_t)image.GetLoadAddress() - (uintptr_t)seg->vmaddr;

           }

           found_text_section = true;

         }

       }

     }

     if (!found_dylib_id_command) {

       if (cmd->cmd == LC_ID_DYLIB) {

         const struct dylib_command *dc =

             reinterpret_cast<const struct dylib_command *>(cmd);

         image.version_ = dc->dylib.current_version;

         found_dylib_id_command = true;

       }

     }

     if (found_dylib_id_command && found_text_section) {

       return true;

     }

     cmd = reinterpret_cast<const struct load_command *>

         (reinterpret_cast<const char *>(cmd) + cmd->cmdsize);

   }

   return false;

 }

 //==============================================================================

 // Initializes vmaddr_, vmsize_, and slide_

 void DynamicImage::CalculateMemoryAndVersionInfo() {

   // unless we can process the header, ensure that calls to

   // IsValid() will return false

   vmaddr_ = 0;

   vmsize_ = 0;

   slide_ = 0;

   version_ = 0;

   // The function template above does all the real work.

   if (Is64Bit())

     FindTextSection<MachO64>(*this);

   else

     FindTextSection<MachO32>(*this);

 }

 //==============================================================================

 // The helper function template abstracts the 32/64-bit differences.

 template<typename MachBits>

 uint32_t GetFileTypeFromHeader(DynamicImage& image) {

   typedef typename MachBits::mach_header_type mach_header_type;

   const mach_header_type* header =

       reinterpret_cast<const mach_header_type*>(&image.header_[0]);

   return header->filetype;

 }

 uint32_t DynamicImage::GetFileType() {

   if (Is64Bit())

     return GetFileTypeFromHeader<MachO64>(*this);

   return GetFileTypeFromHeader<MachO32>(*this);

 }

 #pragma mark -

 //==============================================================================

 // Loads information about dynamically loaded code in the given task.

 DynamicImages::DynamicImages(mach_port_t task)

     : task_(task),

       cpu_type_(DetermineTaskCPUType(task)),

       image_list_() {

   ReadImageInfoForTask();

 }

 template<typename MachBits>

 static uint64_t LookupSymbol(const char* symbol_name,

                              const char* filename,

                              cpu_type_t cpu_type) {

   typedef typename MachBits::nlist_type nlist_type;

   nlist_type symbol_info[8] = {};

   const char *symbolNames[2] = { symbol_name, "\0" };

   nlist_type &list = symbol_info[0];

   int invalidEntriesCount = breakpad_nlist(filename,

                                            &list,

                                            symbolNames,

                                            cpu_type);

   if(invalidEntriesCount != 0) {

     return 0;

   }

   assert(list.n_value);

   return list.n_value;

 }

 #if TARGET_OS_IPHONE

 static bool HasTaskDyldInfo() {

   return true;

 }

 #else

 static SInt32 GetOSVersionInternal() {

   SInt32 os_version = 0;

   Gestalt(gestaltSystemVersion, &os_version);

   return os_version;

 }

 static SInt32 GetOSVersion() {

   static SInt32 os_version = GetOSVersionInternal();

   return os_version;

 }

 static bool HasTaskDyldInfo() {

 #if MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_6

   return true;

 #else

   return GetOSVersion() >= 0x1060;

 #endif

 }

 #endif  // TARGET_OS_IPHONE

 uint64_t DynamicImages::GetDyldAllImageInfosPointer() {

   if (HasTaskDyldInfo()) {

     task_dyld_info_data_t task_dyld_info;

     mach_msg_type_number_t count = TASK_DYLD_INFO_COUNT;

     if (task_info(task_, TASK_DYLD_INFO, (task_info_t)&task_dyld_info,

                   &count) != KERN_SUCCESS) {

       return 0;

     }

     return (uint64_t)task_dyld_info.all_image_info_addr;

   } else {

     const char *imageSymbolName = "_dyld_all_image_infos";

     const char *dyldPath = "/usr/lib/dyld";

     if (Is64Bit())

       return LookupSymbol<MachO64>(imageSymbolName, dyldPath, cpu_type_);

     return LookupSymbol<MachO32>(imageSymbolName, dyldPath, cpu_type_);

   }

 }

 //==============================================================================

 // This code was written using dyld_debug.c (from Darwin) as a guide.

 template<typename MachBits>

 void ReadImageInfo(DynamicImages& images,

                    uint64_t image_list_address) {

   typedef typename MachBits::dyld_image_info dyld_image_info;

   typedef typename MachBits::dyld_all_image_infos dyld_all_image_infos;

   typedef typename MachBits::mach_header_type mach_header_type;

   // Read the structure inside of dyld that contains information about

   // loaded images.  We're reading from the desired task's address space.

   // Here we make the assumption that dyld loaded at the same address in

   // the crashed process vs. this one.  This is an assumption made in

   // "dyld_debug.c" and is said to be nearly always valid.

   vector<uint8_t> dyld_all_info_bytes;

   if (ReadTaskMemory(images.task_,

                      image_list_address,

                      sizeof(dyld_all_image_infos),

                      dyld_all_info_bytes) != KERN_SUCCESS)

     return;

   dyld_all_image_infos *dyldInfo =

     reinterpret_cast<dyld_all_image_infos*>(&dyld_all_info_bytes[0]);

   // number of loaded images

   int count = dyldInfo->infoArrayCount;

   // Read an array of dyld_image_info structures each containing

   // information about a loaded image.

   vector<uint8_t> dyld_info_array_bytes;

     if (ReadTaskMemory(images.task_,

                        dyldInfo->infoArray,

                        count * sizeof(dyld_image_info),

                        dyld_info_array_bytes) != KERN_SUCCESS)

       return;

     dyld_image_info *infoArray =

         reinterpret_cast<dyld_image_info*>(&dyld_info_array_bytes[0]);

     images.image_list_.reserve(count);

     for (int i = 0; i < count; ++i) {

       dyld_image_info &info = infoArray[i];

       // First read just the mach_header from the image in the task.

       vector<uint8_t> mach_header_bytes;

       if (ReadTaskMemory(images.task_,

                          info.load_address_,

                          sizeof(mach_header_type),

                          mach_header_bytes) != KERN_SUCCESS)

         continue;  // bail on this dynamic image

       mach_header_type *header =

           reinterpret_cast<mach_header_type*>(&mach_header_bytes[0]);

       // Now determine the total amount necessary to read the header

       // plus all of the load commands.

       size_t header_size =

           sizeof(mach_header_type) + header->sizeofcmds;

       if (ReadTaskMemory(images.task_,

                          info.load_address_,

                          header_size,

                          mach_header_bytes) != KERN_SUCCESS)

         continue;

       // Read the file name from the task's memory space.

       string file_path;

       if (info.file_path_) {

         // Although we're reading kMaxStringLength bytes, it's copied in the

         // the DynamicImage constructor below with the correct string length,

         // so it's not really wasting memory.

         file_path = ReadTaskString(images.task_, info.file_path_);

       }

       // Create an object representing this image and add it to our list.

       DynamicImage *new_image;

       new_image = new DynamicImage(&mach_header_bytes[0],

                                    header_size,

                                    info.load_address_,

                                    file_path,

                                    static_cast<uintptr_t>(info.file_mod_date_),

                                    images.task_,

                                    images.cpu_type_);

       if (new_image->IsValid()) {

         images.image_list_.push_back(DynamicImageRef(new_image));

       } else {

         delete new_image;

       }

     }

     // sorts based on loading address

     sort(images.image_list_.begin(), images.image_list_.end());

     // remove duplicates - this happens in certain strange cases

     // You can see it in DashboardClient when Google Gadgets plugin

     // is installed.  Apple's crash reporter log and gdb "info shared"

     // both show the same library multiple times at the same address

     vector<DynamicImageRef>::iterator it = unique(images.image_list_.begin(),

                                                   images.image_list_.end());

     images.image_list_.erase(it, images.image_list_.end());

 }

 void DynamicImages::ReadImageInfoForTask() {

   uint64_t imageList = GetDyldAllImageInfosPointer();

   if (imageList) {

     if (Is64Bit())

       ReadImageInfo<MachO64>(*this, imageList);

     else

       ReadImageInfo<MachO32>(*this, imageList);

   }

 }

 //==============================================================================

 DynamicImage  *DynamicImages::GetExecutableImage() {

   int executable_index = GetExecutableImageIndex();

   if (executable_index >= 0) {

     return GetImage(executable_index);

   }

   return NULL;

 }

 //==============================================================================

 // returns -1 if failure to find executable

 int DynamicImages::GetExecutableImageIndex() {

   int image_count = GetImageCount();

   for (int i = 0; i < image_count; ++i) {

     DynamicImage  *image = GetImage(i);

     if (image->GetFileType() == MH_EXECUTE) {

       return i;

     }

   }

   return -1;

 }

 //==============================================================================

 // static

 cpu_type_t DynamicImages::DetermineTaskCPUType(task_t task) {

   if (task == mach_task_self())

     return GetNativeCPUType();

   int mib[CTL_MAXNAME];

   size_t mibLen = CTL_MAXNAME;

   int err = sysctlnametomib("sysctl.proc_cputype", mib, &mibLen);

   if (err == 0) {

     assert(mibLen < CTL_MAXNAME);

     pid_for_task(task, &mib[mibLen]);

     mibLen += 1;

     cpu_type_t cpu_type;

     size_t cpuTypeSize = sizeof(cpu_type);

     sysctl(mib, mibLen, &cpu_type, &cpuTypeSize, 0, 0);

     return cpu_type;

   }

   return GetNativeCPUType();

 }

 }  // namespace google_breakpad