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//===-- sanitizer_procmaps_mac.cc -----------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Information about the process mappings (Mac-specific parts).
//===----------------------------------------------------------------------===//
#include "sanitizer_platform.h"
#if SANITIZER_MAC
#include "sanitizer_common.h"
#include "sanitizer_placement_new.h"
#include "sanitizer_procmaps.h"
#include <mach-o/dyld.h>
#include <mach-o/loader.h>
namespace __sanitizer {
MemoryMappingLayout::MemoryMappingLayout(bool cache_enabled) {
Reset();
}
MemoryMappingLayout::~MemoryMappingLayout() {
}
// More information about Mach-O headers can be found in mach-o/loader.h
// Each Mach-O image has a header (mach_header or mach_header_64) starting with
// a magic number, and a list of linker load commands directly following the
// header.
// A load command is at least two 32-bit words: the command type and the
// command size in bytes. We're interested only in segment load commands
// (LC_SEGMENT and LC_SEGMENT_64), which tell that a part of the file is mapped
// into the task's address space.
// The |vmaddr|, |vmsize| and |fileoff| fields of segment_command or
// segment_command_64 correspond to the memory address, memory size and the
// file offset of the current memory segment.
// Because these fields are taken from the images as is, one needs to add
// _dyld_get_image_vmaddr_slide() to get the actual addresses at runtime.
void MemoryMappingLayout::Reset() {
// Count down from the top.
// TODO(glider): as per man 3 dyld, iterating over the headers with
// _dyld_image_count is thread-unsafe. We need to register callbacks for
// adding and removing images which will invalidate the MemoryMappingLayout
// state.
current_image_ = _dyld_image_count();
current_load_cmd_count_ = -1;
current_load_cmd_addr_ = 0;
current_magic_ = 0;
current_filetype_ = 0;
}
// static
void MemoryMappingLayout::CacheMemoryMappings() {
// No-op on Mac for now.
}
void MemoryMappingLayout::LoadFromCache() {
// No-op on Mac for now.
}
// Next and NextSegmentLoad were inspired by base/sysinfo.cc in
// Google Perftools, https://github.com/gperftools/gperftools.
// NextSegmentLoad scans the current image for the next segment load command
// and returns the start and end addresses and file offset of the corresponding
// segment.
// Note that the segment addresses are not necessarily sorted.
template<u32 kLCSegment, typename SegmentCommand>
bool MemoryMappingLayout::NextSegmentLoad(
uptr *start, uptr *end, uptr *offset,
char filename[], uptr filename_size, uptr *protection) {
const char* lc = current_load_cmd_addr_;
current_load_cmd_addr_ += ((const load_command *)lc)->cmdsize;
if (((const load_command *)lc)->cmd == kLCSegment) {
const sptr dlloff = _dyld_get_image_vmaddr_slide(current_image_);
const SegmentCommand* sc = (const SegmentCommand *)lc;
if (start) *start = sc->vmaddr + dlloff;
if (protection) {
// Return the initial protection.
*protection = sc->initprot;
}
if (end) *end = sc->vmaddr + sc->vmsize + dlloff;
if (offset) {
if (current_filetype_ == /*MH_EXECUTE*/ 0x2) {
*offset = sc->vmaddr;
} else {
*offset = sc->fileoff;
}
}
if (filename) {
internal_strncpy(filename, _dyld_get_image_name(current_image_),
filename_size);
}
return true;
}
return false;
}
bool MemoryMappingLayout::Next(uptr *start, uptr *end, uptr *offset,
char filename[], uptr filename_size,
uptr *protection) {
for (; current_image_ >= 0; current_image_--) {
const mach_header* hdr = _dyld_get_image_header(current_image_);
if (!hdr) continue;
if (current_load_cmd_count_ < 0) {
// Set up for this image;
current_load_cmd_count_ = hdr->ncmds;
current_magic_ = hdr->magic;
current_filetype_ = hdr->filetype;
switch (current_magic_) {
#ifdef MH_MAGIC_64
case MH_MAGIC_64: {
current_load_cmd_addr_ = (char*)hdr + sizeof(mach_header_64);
break;
}
#endif
case MH_MAGIC: {
current_load_cmd_addr_ = (char*)hdr + sizeof(mach_header);
break;
}
default: {
continue;
}
}
}
for (; current_load_cmd_count_ >= 0; current_load_cmd_count_--) {
switch (current_magic_) {
// current_magic_ may be only one of MH_MAGIC, MH_MAGIC_64.
#ifdef MH_MAGIC_64
case MH_MAGIC_64: {
if (NextSegmentLoad<LC_SEGMENT_64, struct segment_command_64>(
start, end, offset, filename, filename_size, protection))
return true;
break;
}
#endif
case MH_MAGIC: {
if (NextSegmentLoad<LC_SEGMENT, struct segment_command>(
start, end, offset, filename, filename_size, protection))
return true;
break;
}
}
}
// If we get here, no more load_cmd's in this image talk about
// segments. Go on to the next image.
}
return false;
}
uptr MemoryMappingLayout::DumpListOfModules(LoadedModule *modules,
uptr max_modules,
string_predicate_t filter) {
Reset();
uptr cur_beg, cur_end, prot;
InternalScopedString module_name(kMaxPathLength);
uptr n_modules = 0;
for (uptr i = 0; n_modules < max_modules &&
Next(&cur_beg, &cur_end, 0, module_name.data(),
module_name.size(), &prot);
i++) {
const char *cur_name = module_name.data();
if (cur_name[0] == '\0')
continue;
if (filter && !filter(cur_name))
continue;
LoadedModule *cur_module = nullptr;
if (n_modules > 0 &&
0 == internal_strcmp(cur_name, modules[n_modules - 1].full_name())) {
cur_module = &modules[n_modules - 1];
} else {
cur_module = &modules[n_modules];
cur_module->set(cur_name, cur_beg);
n_modules++;
}
cur_module->addAddressRange(cur_beg, cur_end, prot & kProtectionExecute);
}
return n_modules;
}
} // namespace __sanitizer
#endif // SANITIZER_MAC
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