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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 "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>
#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,
®ion_base,
®ion_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,
®ion_base2,
®ion_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
//
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 section mach_section_type;
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 section_64 mach_section_type;
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;
typedef typename MachBits::mach_section_type mach_section_type;
const mach_header_type* header =
reinterpret_cast<const mach_header_type*>(&image.header_[0]);
if(header->magic != MachBits::magic) {
return false;
}
bool is_in_shared_cache = ((header->flags & MH_SHAREDCACHE) != 0);
if (is_in_shared_cache) {
image.slide_ = image.shared_cache_slide_;
}
const struct load_command *cmd =
reinterpret_cast<const struct load_command *>(header + 1);
bool retval = false;
uint32_t num_data_sections = 0;
const mach_section_type *data_sections = NULL;
uint32_t num_data_dirty_sections = 0;
const mach_section_type *data_dirty_sections = NULL;
bool found_text_section = false;
bool found_dylib_id_command = false;
for (unsigned int i = 0; cmd && (i < header->ncmds); ++i) {
if (!data_sections) {
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, "__DATA")) {
num_data_sections = seg->nsects;
data_sections = reinterpret_cast<const mach_section_type *>(seg + 1);
}
}
}
if (!data_dirty_sections) {
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, "__DATA_DIRTY")) {
num_data_dirty_sections = seg->nsects;
data_dirty_sections =
reinterpret_cast<const mach_section_type *>(seg + 1);
}
}
}
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 (!is_in_shared_cache) {
if (seg->fileoff == 0 && seg->filesize != 0) {
image.slide_ =
(uintptr_t)image.GetLoadAddress() - (uintptr_t)seg->vmaddr;
}
}
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);
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 &&
data_sections && data_dirty_sections) {
break;
}
cmd = reinterpret_cast<const struct load_command *>
(reinterpret_cast<const char *>(cmd) + cmd->cmdsize);
}
if (found_dylib_id_command && found_text_section) {
retval = true;
}
// The __DYLD,__crash_info section may not be accessible in child process
// modules that aren't dyld or in the dyld shared cache.
if (image.GetIsDyld() || is_in_shared_cache) {
for (unsigned int i = 0; i < num_data_sections; ++i) {
if (!strcmp(data_sections[i].sectname, "__crash_info")) {
ReadTaskMemory(image.task_,
data_sections[i].addr + image.slide_,
data_sections[i].size,
image.crash_info_);
return retval;
}
}
// __crash_info might be in the __DATA_DIRTY segment.
for (unsigned int i = 0; i < num_data_dirty_sections; ++i) {
if (!strcmp(data_dirty_sections[i].sectname, "__crash_info")) {
ReadTaskMemory(image.task_,
data_dirty_sections[i].addr + image.slide_,
data_dirty_sections[i].size,
image.crash_info_);
return retval;
}
}
}
return retval;
}
//==============================================================================
// 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;
}
uint64_t DynamicImages::GetDyldAllImageInfosPointer() {
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;
}
//==============================================================================
// This code was written using dyld_debug.c (from Darwin) as a guide.
template<typename MachBits>
void ReadOneImageInfo(DynamicImages& images, uint64_t image_address,
uint64_t file_path_address, uint64_t file_mod_date,
uint64_t shared_cache_slide, bool is_dyld) {
typedef typename MachBits::mach_header_type mach_header_type;
// First read just the mach_header from the image in the task.
vector<uint8_t> mach_header_bytes;
if (ReadTaskMemory(images.task_,
image_address,
sizeof(mach_header_type),
mach_header_bytes) != KERN_SUCCESS) {
return; // bail on this dynamic image
}
mach_header_type *header =
reinterpret_cast<mach_header_type*>(&mach_header_bytes[0]);
if (header->magic != MachBits::magic) {
return;
}
cpu_subtype_t cpusubtype = (header->cpusubtype & ~CPU_SUBTYPE_MASK);
// 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_,
image_address,
header_size,
mach_header_bytes) != KERN_SUCCESS) {
return;
}
// Read the file name from the task's memory space.
string file_path;
if (file_path_address) {
// 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_, file_path_address);
}
// 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,
image_address,
file_path,
static_cast<uintptr_t>(file_mod_date),
images.task_,
images.cpu_type_,
cpusubtype,
shared_cache_slide,
is_dyld);
if (new_image->IsValid()) {
images.image_list_.push_back(DynamicImageRef(new_image));
} else {
delete new_image;
}
}
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;
// 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]);
// Add room for dyld at the end
images.image_list_.reserve(count + 1);
for (int i = 0; i < count; ++i) {
dyld_image_info &info = infoArray[i];
ReadOneImageInfo<MachBits>(images, info.load_address_,
info.file_path_, info.file_mod_date_,
dyldInfo->sharedCacheSlide,
/* is_dyld */ false);
}
// Add an image for dyld itself. It doesn't appear in the standard list of
// modules.
uint64_t dyld_address = (uint64_t) dyldInfo->dyldImageLoadAddress;
if (dyld_address) {
ReadOneImageInfo<MachBits>(images, dyld_address,
(uint64_t) dyldInfo->dyldPath,
/* file_mod_date */ 0,
dyldInfo->sharedCacheSlide,
/* is_dyld */ true);
}
// 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, static_cast<u_int>(mibLen), &cpu_type, &cpuTypeSize, 0, 0);
return cpu_type;
}
return GetNativeCPUType();
}
} // namespace google_breakpad