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      1 // Copyright 2012 the V8 project authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 // Platform-specific code for MacOS goes here. For the POSIX-compatible
      6 // parts, the implementation is in platform-posix.cc.
      7 
      8 #include <dlfcn.h>
      9 #include <mach/mach_init.h>
     10 #include <mach-o/dyld.h>
     11 #include <mach-o/getsect.h>
     12 #include <sys/mman.h>
     13 #include <unistd.h>
     14 
     15 #include <AvailabilityMacros.h>
     16 
     17 #include <errno.h>
     18 #include <libkern/OSAtomic.h>
     19 #include <mach/mach.h>
     20 #include <mach/semaphore.h>
     21 #include <mach/task.h>
     22 #include <mach/vm_statistics.h>
     23 #include <pthread.h>
     24 #include <semaphore.h>
     25 #include <signal.h>
     26 #include <stdarg.h>
     27 #include <stdlib.h>
     28 #include <string.h>
     29 #include <sys/resource.h>
     30 #include <sys/sysctl.h>
     31 #include <sys/time.h>
     32 #include <sys/types.h>
     33 
     34 #include <cmath>
     35 
     36 #undef MAP_TYPE
     37 
     38 #include "src/base/macros.h"
     39 #include "src/base/platform/platform.h"
     40 
     41 
     42 namespace v8 {
     43 namespace base {
     44 
     45 
     46 // Constants used for mmap.
     47 // kMmapFd is used to pass vm_alloc flags to tag the region with the user
     48 // defined tag 255 This helps identify V8-allocated regions in memory analysis
     49 // tools like vmmap(1).
     50 static const int kMmapFd = VM_MAKE_TAG(255);
     51 static const off_t kMmapFdOffset = 0;
     52 
     53 
     54 void* OS::Allocate(const size_t requested,
     55                    size_t* allocated,
     56                    bool is_executable) {
     57   const size_t msize = RoundUp(requested, getpagesize());
     58   int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0);
     59   void* mbase = mmap(OS::GetRandomMmapAddr(),
     60                      msize,
     61                      prot,
     62                      MAP_PRIVATE | MAP_ANON,
     63                      kMmapFd,
     64                      kMmapFdOffset);
     65   if (mbase == MAP_FAILED) return NULL;
     66   *allocated = msize;
     67   return mbase;
     68 }
     69 
     70 
     71 class PosixMemoryMappedFile : public OS::MemoryMappedFile {
     72  public:
     73   PosixMemoryMappedFile(FILE* file, void* memory, int size)
     74     : file_(file), memory_(memory), size_(size) { }
     75   virtual ~PosixMemoryMappedFile();
     76   virtual void* memory() { return memory_; }
     77   virtual int size() { return size_; }
     78  private:
     79   FILE* file_;
     80   void* memory_;
     81   int size_;
     82 };
     83 
     84 
     85 OS::MemoryMappedFile* OS::MemoryMappedFile::open(const char* name) {
     86   FILE* file = fopen(name, "r+");
     87   if (file == NULL) return NULL;
     88 
     89   fseek(file, 0, SEEK_END);
     90   int size = ftell(file);
     91 
     92   void* memory =
     93       mmap(OS::GetRandomMmapAddr(),
     94            size,
     95            PROT_READ | PROT_WRITE,
     96            MAP_SHARED,
     97            fileno(file),
     98            0);
     99   return new PosixMemoryMappedFile(file, memory, size);
    100 }
    101 
    102 
    103 OS::MemoryMappedFile* OS::MemoryMappedFile::create(const char* name, int size,
    104     void* initial) {
    105   FILE* file = fopen(name, "w+");
    106   if (file == NULL) return NULL;
    107   int result = fwrite(initial, size, 1, file);
    108   if (result < 1) {
    109     fclose(file);
    110     return NULL;
    111   }
    112   void* memory =
    113       mmap(OS::GetRandomMmapAddr(),
    114           size,
    115           PROT_READ | PROT_WRITE,
    116           MAP_SHARED,
    117           fileno(file),
    118           0);
    119   return new PosixMemoryMappedFile(file, memory, size);
    120 }
    121 
    122 
    123 PosixMemoryMappedFile::~PosixMemoryMappedFile() {
    124   if (memory_) OS::Free(memory_, size_);
    125   fclose(file_);
    126 }
    127 
    128 
    129 std::vector<OS::SharedLibraryAddress> OS::GetSharedLibraryAddresses() {
    130   std::vector<SharedLibraryAddress> result;
    131   unsigned int images_count = _dyld_image_count();
    132   for (unsigned int i = 0; i < images_count; ++i) {
    133     const mach_header* header = _dyld_get_image_header(i);
    134     if (header == NULL) continue;
    135 #if V8_HOST_ARCH_X64
    136     uint64_t size;
    137     char* code_ptr = getsectdatafromheader_64(
    138         reinterpret_cast<const mach_header_64*>(header),
    139         SEG_TEXT,
    140         SECT_TEXT,
    141         &size);
    142 #else
    143     unsigned int size;
    144     char* code_ptr = getsectdatafromheader(header, SEG_TEXT, SECT_TEXT, &size);
    145 #endif
    146     if (code_ptr == NULL) continue;
    147     const uintptr_t slide = _dyld_get_image_vmaddr_slide(i);
    148     const uintptr_t start = reinterpret_cast<uintptr_t>(code_ptr) + slide;
    149     result.push_back(
    150         SharedLibraryAddress(_dyld_get_image_name(i), start, start + size));
    151   }
    152   return result;
    153 }
    154 
    155 
    156 void OS::SignalCodeMovingGC() {
    157 }
    158 
    159 
    160 const char* OS::LocalTimezone(double time, TimezoneCache* cache) {
    161   if (std::isnan(time)) return "";
    162   time_t tv = static_cast<time_t>(std::floor(time/msPerSecond));
    163   struct tm* t = localtime(&tv);
    164   if (NULL == t) return "";
    165   return t->tm_zone;
    166 }
    167 
    168 
    169 double OS::LocalTimeOffset(TimezoneCache* cache) {
    170   time_t tv = time(NULL);
    171   struct tm* t = localtime(&tv);
    172   // tm_gmtoff includes any daylight savings offset, so subtract it.
    173   return static_cast<double>(t->tm_gmtoff * msPerSecond -
    174                              (t->tm_isdst > 0 ? 3600 * msPerSecond : 0));
    175 }
    176 
    177 
    178 VirtualMemory::VirtualMemory() : address_(NULL), size_(0) { }
    179 
    180 
    181 VirtualMemory::VirtualMemory(size_t size)
    182     : address_(ReserveRegion(size)), size_(size) { }
    183 
    184 
    185 VirtualMemory::VirtualMemory(size_t size, size_t alignment)
    186     : address_(NULL), size_(0) {
    187   DCHECK((alignment % OS::AllocateAlignment()) == 0);
    188   size_t request_size = RoundUp(size + alignment,
    189                                 static_cast<intptr_t>(OS::AllocateAlignment()));
    190   void* reservation = mmap(OS::GetRandomMmapAddr(),
    191                            request_size,
    192                            PROT_NONE,
    193                            MAP_PRIVATE | MAP_ANON | MAP_NORESERVE,
    194                            kMmapFd,
    195                            kMmapFdOffset);
    196   if (reservation == MAP_FAILED) return;
    197 
    198   uint8_t* base = static_cast<uint8_t*>(reservation);
    199   uint8_t* aligned_base = RoundUp(base, alignment);
    200   DCHECK_LE(base, aligned_base);
    201 
    202   // Unmap extra memory reserved before and after the desired block.
    203   if (aligned_base != base) {
    204     size_t prefix_size = static_cast<size_t>(aligned_base - base);
    205     OS::Free(base, prefix_size);
    206     request_size -= prefix_size;
    207   }
    208 
    209   size_t aligned_size = RoundUp(size, OS::AllocateAlignment());
    210   DCHECK_LE(aligned_size, request_size);
    211 
    212   if (aligned_size != request_size) {
    213     size_t suffix_size = request_size - aligned_size;
    214     OS::Free(aligned_base + aligned_size, suffix_size);
    215     request_size -= suffix_size;
    216   }
    217 
    218   DCHECK(aligned_size == request_size);
    219 
    220   address_ = static_cast<void*>(aligned_base);
    221   size_ = aligned_size;
    222 }
    223 
    224 
    225 VirtualMemory::~VirtualMemory() {
    226   if (IsReserved()) {
    227     bool result = ReleaseRegion(address(), size());
    228     DCHECK(result);
    229     USE(result);
    230   }
    231 }
    232 
    233 
    234 bool VirtualMemory::IsReserved() {
    235   return address_ != NULL;
    236 }
    237 
    238 
    239 void VirtualMemory::Reset() {
    240   address_ = NULL;
    241   size_ = 0;
    242 }
    243 
    244 
    245 bool VirtualMemory::Commit(void* address, size_t size, bool is_executable) {
    246   return CommitRegion(address, size, is_executable);
    247 }
    248 
    249 
    250 bool VirtualMemory::Uncommit(void* address, size_t size) {
    251   return UncommitRegion(address, size);
    252 }
    253 
    254 
    255 bool VirtualMemory::Guard(void* address) {
    256   OS::Guard(address, OS::CommitPageSize());
    257   return true;
    258 }
    259 
    260 
    261 void* VirtualMemory::ReserveRegion(size_t size) {
    262   void* result = mmap(OS::GetRandomMmapAddr(),
    263                       size,
    264                       PROT_NONE,
    265                       MAP_PRIVATE | MAP_ANON | MAP_NORESERVE,
    266                       kMmapFd,
    267                       kMmapFdOffset);
    268 
    269   if (result == MAP_FAILED) return NULL;
    270 
    271   return result;
    272 }
    273 
    274 
    275 bool VirtualMemory::CommitRegion(void* address,
    276                                  size_t size,
    277                                  bool is_executable) {
    278   int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0);
    279   if (MAP_FAILED == mmap(address,
    280                          size,
    281                          prot,
    282                          MAP_PRIVATE | MAP_ANON | MAP_FIXED,
    283                          kMmapFd,
    284                          kMmapFdOffset)) {
    285     return false;
    286   }
    287   return true;
    288 }
    289 
    290 
    291 bool VirtualMemory::UncommitRegion(void* address, size_t size) {
    292   return mmap(address,
    293               size,
    294               PROT_NONE,
    295               MAP_PRIVATE | MAP_ANON | MAP_NORESERVE | MAP_FIXED,
    296               kMmapFd,
    297               kMmapFdOffset) != MAP_FAILED;
    298 }
    299 
    300 
    301 bool VirtualMemory::ReleaseRegion(void* address, size_t size) {
    302   return munmap(address, size) == 0;
    303 }
    304 
    305 
    306 bool VirtualMemory::HasLazyCommits() {
    307   return false;
    308 }
    309 
    310 } }  // namespace v8::base
    311