deps/v8/src/base/platform/platform-cygwin.cc
// 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);
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);
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;
}
class PosixMemoryMappedFile : public OS::MemoryMappedFile {
public:
PosixMemoryMappedFile(FILE* file, void* memory, int size)
: file_(file), memory_(memory), size_(size) { }
virtual ~PosixMemoryMappedFile();
virtual void* memory() { return memory_; }
virtual int size() { return size_; }
private:
FILE* file_;
void* memory_;
int size_;
};
OS::MemoryMappedFile* OS::MemoryMappedFile::open(const char* name) {
FILE* file = fopen(name, "r+");
if (file == NULL) return NULL;
fseek(file, 0, SEEK_END);
int size = ftell(file);
void* memory =
mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fileno(file), 0);
return new PosixMemoryMappedFile(file, memory, size);
}
OS::MemoryMappedFile* OS::MemoryMappedFile::create(const char* name, int size,
void* initial) {
FILE* file = fopen(name, "w+");
if (file == NULL) return NULL;
int result = fwrite(initial, size, 1, file);
if (result < 1) {
fclose(file);
return NULL;
}
void* memory =
mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fileno(file), 0);
return new PosixMemoryMappedFile(file, memory, size);
}
PosixMemoryMappedFile::~PosixMemoryMappedFile() {
if (memory_) munmap(memory_, size_);
fclose(file_);
}
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(IsAligned(alignment, static_cast<intptr_t>(OS::AllocateAlignment())));
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 v8::base