// Copyright 2012 the V8 project authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. // Platform-specific code for Cygwin goes here. For the POSIX-compatible // parts, the implementation is in platform-posix.cc. #include <errno.h> #include <pthread.h> #include <semaphore.h> #include <stdarg.h> #include <strings.h> // index #include <sys/mman.h> // mmap & munmap #include <sys/time.h> #include <unistd.h> // sysconf #include <cmath> #undef MAP_TYPE #include "src/base/macros.h" #include "src/base/platform/platform.h" #include "src/base/win32-headers.h" namespace v8 { namespace base { const char* OS::LocalTimezone(double time, TimezoneCache* cache) { if (std::isnan(time)) return ""; time_t tv = static_cast<time_t>(std::floor(time/msPerSecond)); struct tm* t = localtime(&tv); // NOLINT(runtime/threadsafe_fn) if (NULL == t) return ""; return tzname[0]; // The location of the timezone string on Cygwin. } double OS::LocalTimeOffset(TimezoneCache* cache) { // On Cygwin, struct tm does not contain a tm_gmtoff field. time_t utc = time(NULL); DCHECK(utc != -1); struct tm* loc = localtime(&utc); // NOLINT(runtime/threadsafe_fn) DCHECK(loc != NULL); // time - localtime includes any daylight savings offset, so subtract it. return static_cast<double>((mktime(loc) - utc) * msPerSecond - (loc->tm_isdst > 0 ? 3600 * msPerSecond : 0)); } void* OS::Allocate(const size_t requested, size_t* allocated, bool is_executable) { const size_t msize = RoundUp(requested, sysconf(_SC_PAGESIZE)); int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0); void* mbase = mmap(NULL, msize, prot, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); if (mbase == MAP_FAILED) return NULL; *allocated = msize; return mbase; } std::vector<OS::SharedLibraryAddress> OS::GetSharedLibraryAddresses() { std::vector<SharedLibraryAddresses> result; // This function assumes that the layout of the file is as follows: // hex_start_addr-hex_end_addr rwxp <unused data> [binary_file_name] // If we encounter an unexpected situation we abort scanning further entries. FILE* fp = fopen("/proc/self/maps", "r"); if (fp == NULL) return result; // Allocate enough room to be able to store a full file name. const int kLibNameLen = FILENAME_MAX + 1; char* lib_name = reinterpret_cast<char*>(malloc(kLibNameLen)); // This loop will terminate once the scanning hits an EOF. while (true) { uintptr_t start, end; char attr_r, attr_w, attr_x, attr_p; // Parse the addresses and permission bits at the beginning of the line. if (fscanf(fp, "%" V8PRIxPTR "-%" V8PRIxPTR, &start, &end) != 2) break; if (fscanf(fp, " %c%c%c%c", &attr_r, &attr_w, &attr_x, &attr_p) != 4) break; int c; if (attr_r == 'r' && attr_w != 'w' && attr_x == 'x') { // Found a read-only executable entry. Skip characters until we reach // the beginning of the filename or the end of the line. do { c = getc(fp); } while ((c != EOF) && (c != '\n') && (c != '/')); if (c == EOF) break; // EOF: Was unexpected, just exit. // Process the filename if found. if (c == '/') { ungetc(c, fp); // Push the '/' back into the stream to be read below. // Read to the end of the line. Exit if the read fails. if (fgets(lib_name, kLibNameLen, fp) == NULL) break; // Drop the newline character read by fgets. We do not need to check // for a zero-length string because we know that we at least read the // '/' character. lib_name[strlen(lib_name) - 1] = '\0'; } else { // No library name found, just record the raw address range. snprintf(lib_name, kLibNameLen, "%08" V8PRIxPTR "-%08" V8PRIxPTR, start, end); } result.push_back(SharedLibraryAddress(lib_name, start, end)); } else { // Entry not describing executable data. Skip to end of line to set up // reading the next entry. do { c = getc(fp); } while ((c != EOF) && (c != '\n')); if (c == EOF) break; } } free(lib_name); fclose(fp); return result; } void OS::SignalCodeMovingGC() { // Nothing to do on Cygwin. } // The VirtualMemory implementation is taken from platform-win32.cc. // The mmap-based virtual memory implementation as it is used on most posix // platforms does not work well because Cygwin does not support MAP_FIXED. // This causes VirtualMemory::Commit to not always commit the memory region // specified. static void* RandomizedVirtualAlloc(size_t size, int action, int protection) { LPVOID base = NULL; if (protection == PAGE_EXECUTE_READWRITE || protection == PAGE_NOACCESS) { // For exectutable pages try and randomize the allocation address for (size_t attempts = 0; base == NULL && attempts < 3; ++attempts) { base = VirtualAlloc(OS::GetRandomMmapAddr(), size, action, protection); } } // After three attempts give up and let the OS find an address to use. if (base == NULL) base = VirtualAlloc(NULL, size, action, protection); return base; } VirtualMemory::VirtualMemory() : address_(NULL), size_(0) { } VirtualMemory::VirtualMemory(size_t size) : address_(ReserveRegion(size)), size_(size) { } VirtualMemory::VirtualMemory(size_t size, size_t alignment) : address_(NULL), size_(0) { DCHECK((alignment % OS::AllocateAlignment()) == 0); size_t request_size = RoundUp(size + alignment, static_cast<intptr_t>(OS::AllocateAlignment())); void* address = ReserveRegion(request_size); if (address == NULL) return; uint8_t* base = RoundUp(static_cast<uint8_t*>(address), alignment); // Try reducing the size by freeing and then reallocating a specific area. bool result = ReleaseRegion(address, request_size); USE(result); DCHECK(result); address = VirtualAlloc(base, size, MEM_RESERVE, PAGE_NOACCESS); if (address != NULL) { request_size = size; DCHECK(base == static_cast<uint8_t*>(address)); } else { // Resizing failed, just go with a bigger area. address = ReserveRegion(request_size); if (address == NULL) return; } address_ = address; size_ = request_size; } VirtualMemory::~VirtualMemory() { if (IsReserved()) { bool result = ReleaseRegion(address_, size_); DCHECK(result); USE(result); } } bool VirtualMemory::IsReserved() { return address_ != NULL; } void VirtualMemory::Reset() { address_ = NULL; size_ = 0; } bool VirtualMemory::Commit(void* address, size_t size, bool is_executable) { return CommitRegion(address, size, is_executable); } bool VirtualMemory::Uncommit(void* address, size_t size) { DCHECK(IsReserved()); return UncommitRegion(address, size); } void* VirtualMemory::ReserveRegion(size_t size) { return RandomizedVirtualAlloc(size, MEM_RESERVE, PAGE_NOACCESS); } bool VirtualMemory::CommitRegion(void* base, size_t size, bool is_executable) { int prot = is_executable ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE; if (NULL == VirtualAlloc(base, size, MEM_COMMIT, prot)) { return false; } return true; } bool VirtualMemory::Guard(void* address) { if (NULL == VirtualAlloc(address, OS::CommitPageSize(), MEM_COMMIT, PAGE_NOACCESS)) { return false; } return true; } bool VirtualMemory::UncommitRegion(void* base, size_t size) { return VirtualFree(base, size, MEM_DECOMMIT) != 0; } bool VirtualMemory::ReleaseRegion(void* base, size_t size) { return VirtualFree(base, 0, MEM_RELEASE) != 0; } bool VirtualMemory::HasLazyCommits() { // TODO(alph): implement for the platform. return false; } } // namespace base } // namespace v8