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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 FreeBSD goes here. For the POSIX-compatible
      6 // parts, the implementation is in platform-posix.cc.
      7 
      8 #include <pthread.h>
      9 #include <semaphore.h>
     10 #include <signal.h>
     11 #include <stdlib.h>
     12 #include <sys/resource.h>
     13 #include <sys/time.h>
     14 #include <sys/types.h>
     15 #include <sys/ucontext.h>
     16 
     17 #include <sys/fcntl.h>  // open
     18 #include <sys/mman.h>   // mmap & munmap
     19 #include <sys/stat.h>   // open
     20 #include <unistd.h>     // getpagesize
     21 // If you don't have execinfo.h then you need devel/libexecinfo from ports.
     22 #include <errno.h>
     23 #include <limits.h>
     24 #include <stdarg.h>
     25 #include <strings.h>    // index
     26 
     27 #include <cmath>
     28 
     29 #undef MAP_TYPE
     30 
     31 #include "src/base/macros.h"
     32 #include "src/base/platform/platform.h"
     33 
     34 
     35 namespace v8 {
     36 namespace base {
     37 
     38 
     39 const char* OS::LocalTimezone(double time, TimezoneCache* cache) {
     40   if (std::isnan(time)) return "";
     41   time_t tv = static_cast<time_t>(std::floor(time/msPerSecond));
     42   struct tm* t = localtime(&tv);  // NOLINT(runtime/threadsafe_fn)
     43   if (NULL == t) return "";
     44   return t->tm_zone;
     45 }
     46 
     47 
     48 double OS::LocalTimeOffset(TimezoneCache* cache) {
     49   time_t tv = time(NULL);
     50   struct tm* t = localtime(&tv);  // NOLINT(runtime/threadsafe_fn)
     51   // tm_gmtoff includes any daylight savings offset, so subtract it.
     52   return static_cast<double>(t->tm_gmtoff * msPerSecond -
     53                              (t->tm_isdst > 0 ? 3600 * msPerSecond : 0));
     54 }
     55 
     56 
     57 void* OS::Allocate(const size_t requested,
     58                    size_t* allocated,
     59                    bool executable) {
     60   const size_t msize = RoundUp(requested, getpagesize());
     61   int prot = PROT_READ | PROT_WRITE | (executable ? PROT_EXEC : 0);
     62   void* mbase = mmap(NULL, msize, prot, MAP_PRIVATE | MAP_ANON, -1, 0);
     63 
     64   if (mbase == MAP_FAILED) return NULL;
     65   *allocated = msize;
     66   return mbase;
     67 }
     68 
     69 
     70 static unsigned StringToLong(char* buffer) {
     71   return static_cast<unsigned>(strtol(buffer, NULL, 16));  // NOLINT
     72 }
     73 
     74 
     75 std::vector<OS::SharedLibraryAddress> OS::GetSharedLibraryAddresses() {
     76   std::vector<SharedLibraryAddress> result;
     77   static const int MAP_LENGTH = 1024;
     78   int fd = open("/proc/self/maps", O_RDONLY);
     79   if (fd < 0) return result;
     80   while (true) {
     81     char addr_buffer[11];
     82     addr_buffer[0] = '0';
     83     addr_buffer[1] = 'x';
     84     addr_buffer[10] = 0;
     85     ssize_t bytes_read = read(fd, addr_buffer + 2, 8);
     86     if (bytes_read < 8) break;
     87     unsigned start = StringToLong(addr_buffer);
     88     bytes_read = read(fd, addr_buffer + 2, 1);
     89     if (bytes_read < 1) break;
     90     if (addr_buffer[2] != '-') break;
     91     bytes_read = read(fd, addr_buffer + 2, 8);
     92     if (bytes_read < 8) break;
     93     unsigned end = StringToLong(addr_buffer);
     94     char buffer[MAP_LENGTH];
     95     bytes_read = -1;
     96     do {
     97       bytes_read++;
     98       if (bytes_read >= MAP_LENGTH - 1)
     99         break;
    100       bytes_read = read(fd, buffer + bytes_read, 1);
    101       if (bytes_read < 1) break;
    102     } while (buffer[bytes_read] != '\n');
    103     buffer[bytes_read] = 0;
    104     // Ignore mappings that are not executable.
    105     if (buffer[3] != 'x') continue;
    106     char* start_of_path = index(buffer, '/');
    107     // There may be no filename in this line.  Skip to next.
    108     if (start_of_path == NULL) continue;
    109     buffer[bytes_read] = 0;
    110     result.push_back(SharedLibraryAddress(start_of_path, start, end));
    111   }
    112   close(fd);
    113   return result;
    114 }
    115 
    116 
    117 void OS::SignalCodeMovingGC() {
    118 }
    119 
    120 
    121 
    122 // Constants used for mmap.
    123 static const int kMmapFd = -1;
    124 static const int kMmapFdOffset = 0;
    125 
    126 
    127 VirtualMemory::VirtualMemory() : address_(NULL), size_(0) { }
    128 
    129 
    130 VirtualMemory::VirtualMemory(size_t size)
    131     : address_(ReserveRegion(size)), size_(size) { }
    132 
    133 
    134 VirtualMemory::VirtualMemory(size_t size, size_t alignment)
    135     : address_(NULL), size_(0) {
    136   DCHECK((alignment % OS::AllocateAlignment()) == 0);
    137   size_t request_size = RoundUp(size + alignment,
    138                                 static_cast<intptr_t>(OS::AllocateAlignment()));
    139   void* reservation = mmap(OS::GetRandomMmapAddr(),
    140                            request_size,
    141                            PROT_NONE,
    142                            MAP_PRIVATE | MAP_ANON,
    143                            kMmapFd,
    144                            kMmapFdOffset);
    145   if (reservation == MAP_FAILED) return;
    146 
    147   uint8_t* base = static_cast<uint8_t*>(reservation);
    148   uint8_t* aligned_base = RoundUp(base, alignment);
    149   DCHECK_LE(base, aligned_base);
    150 
    151   // Unmap extra memory reserved before and after the desired block.
    152   if (aligned_base != base) {
    153     size_t prefix_size = static_cast<size_t>(aligned_base - base);
    154     OS::Free(base, prefix_size);
    155     request_size -= prefix_size;
    156   }
    157 
    158   size_t aligned_size = RoundUp(size, OS::AllocateAlignment());
    159   DCHECK_LE(aligned_size, request_size);
    160 
    161   if (aligned_size != request_size) {
    162     size_t suffix_size = request_size - aligned_size;
    163     OS::Free(aligned_base + aligned_size, suffix_size);
    164     request_size -= suffix_size;
    165   }
    166 
    167   DCHECK(aligned_size == request_size);
    168 
    169   address_ = static_cast<void*>(aligned_base);
    170   size_ = aligned_size;
    171 }
    172 
    173 
    174 VirtualMemory::~VirtualMemory() {
    175   if (IsReserved()) {
    176     bool result = ReleaseRegion(address(), size());
    177     DCHECK(result);
    178     USE(result);
    179   }
    180 }
    181 
    182 
    183 bool VirtualMemory::IsReserved() {
    184   return address_ != NULL;
    185 }
    186 
    187 
    188 void VirtualMemory::Reset() {
    189   address_ = NULL;
    190   size_ = 0;
    191 }
    192 
    193 
    194 bool VirtualMemory::Commit(void* address, size_t size, bool is_executable) {
    195   return CommitRegion(address, size, is_executable);
    196 }
    197 
    198 
    199 bool VirtualMemory::Uncommit(void* address, size_t size) {
    200   return UncommitRegion(address, size);
    201 }
    202 
    203 
    204 bool VirtualMemory::Guard(void* address) {
    205   OS::Guard(address, OS::CommitPageSize());
    206   return true;
    207 }
    208 
    209 
    210 void* VirtualMemory::ReserveRegion(size_t size) {
    211   void* result = mmap(OS::GetRandomMmapAddr(),
    212                       size,
    213                       PROT_NONE,
    214                       MAP_PRIVATE | MAP_ANON,
    215                       kMmapFd,
    216                       kMmapFdOffset);
    217 
    218   if (result == MAP_FAILED) return NULL;
    219 
    220   return result;
    221 }
    222 
    223 
    224 bool VirtualMemory::CommitRegion(void* base, size_t size, bool is_executable) {
    225   int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0);
    226   if (MAP_FAILED == mmap(base,
    227                          size,
    228                          prot,
    229                          MAP_PRIVATE | MAP_ANON | MAP_FIXED,
    230                          kMmapFd,
    231                          kMmapFdOffset)) {
    232     return false;
    233   }
    234   return true;
    235 }
    236 
    237 
    238 bool VirtualMemory::UncommitRegion(void* base, size_t size) {
    239   return mmap(base,
    240               size,
    241               PROT_NONE,
    242               MAP_PRIVATE | MAP_ANON | MAP_FIXED,
    243               kMmapFd,
    244               kMmapFdOffset) != MAP_FAILED;
    245 }
    246 
    247 
    248 bool VirtualMemory::ReleaseRegion(void* base, size_t size) {
    249   return munmap(base, size) == 0;
    250 }
    251 
    252 
    253 bool VirtualMemory::HasLazyCommits() {
    254   // TODO(alph): implement for the platform.
    255   return false;
    256 }
    257 
    258 }  // namespace base
    259 }  // namespace v8
    260