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// Copyright 2014 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 AIX goes here. For the POSIX comaptible parts
// the implementation is in platform-posix.cc.
#include <pthread.h>
#include <semaphore.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/resource.h>
#include <sys/time.h>
#include <sys/ucontext.h>
#include <errno.h>
#include <fcntl.h> // open
#include <limits.h>
#include <stdarg.h>
#include <strings.h> // index
#include <sys/mman.h> // mmap & munmap
#include <sys/stat.h> // open
#include <sys/types.h> // mmap & munmap
#include <unistd.h> // getpagesize
#include <cmath>
#undef MAP_TYPE
#include "src/base/macros.h"
#include "src/base/platform/platform-posix.h"
#include "src/base/platform/platform.h"
namespace v8 {
namespace base {
int64_t get_gmt_offset(const tm& localtm) {
// replacement for tm->tm_gmtoff field in glibc
// returns seconds east of UTC, taking DST into account
struct timeval tv;
struct timezone tz;
int ret_code = gettimeofday(&tv, &tz);
// 0 = success, -1 = failure
DCHECK_NE(ret_code, -1);
if (ret_code == -1) {
return 0;
}
return (-tz.tz_minuteswest * 60) + (localtm.tm_isdst > 0 ? 3600 : 0);
}
class AIXTimezoneCache : public PosixTimezoneCache {
const char* LocalTimezone(double time) override;
double LocalTimeOffset(double time_ms, bool is_utc) override;
~AIXTimezoneCache() override {}
};
const char* AIXTimezoneCache::LocalTimezone(double time_ms) {
if (std::isnan(time_ms)) return "";
time_t tv = static_cast<time_t>(floor(time_ms / msPerSecond));
struct tm tm;
struct tm* t = localtime_r(&tv, &tm);
if (nullptr == t) return "";
return tzname[0]; // The location of the timezone string on AIX.
}
double AIXTimezoneCache::LocalTimeOffset(double time_ms, bool is_utc) {
// On AIX, struct tm does not contain a tm_gmtoff field, use get_gmt_offset
// helper function
time_t utc = time(nullptr);
DCHECK_NE(utc, -1);
struct tm tm;
struct tm* loc = localtime_r(&utc, &tm);
DCHECK_NOT_NULL(loc);
return static_cast<double>(get_gmt_offset(*loc) * msPerSecond -
(loc->tm_isdst > 0 ? 3600 * msPerSecond : 0));
}
TimezoneCache* OS::CreateTimezoneCache() { return new AIXTimezoneCache(); }
static unsigned StringToLong(char* buffer) {
return static_cast<unsigned>(strtol(buffer, nullptr, 16));
}
std::vector<OS::SharedLibraryAddress> OS::GetSharedLibraryAddresses() {
std::vector<SharedLibraryAddress> result;
static const int MAP_LENGTH = 1024;
int fd = open("/proc/self/maps", O_RDONLY);
if (fd < 0) return result;
while (true) {
char addr_buffer[11];
addr_buffer[0] = '0';
addr_buffer[1] = 'x';
addr_buffer[10] = 0;
ssize_t rc = read(fd, addr_buffer + 2, 8);
if (rc < 8) break;
unsigned start = StringToLong(addr_buffer);
rc = read(fd, addr_buffer + 2, 1);
if (rc < 1) break;
if (addr_buffer[2] != '-') break;
rc = read(fd, addr_buffer + 2, 8);
if (rc < 8) break;
unsigned end = StringToLong(addr_buffer);
char buffer[MAP_LENGTH];
int bytes_read = -1;
do {
bytes_read++;
if (bytes_read >= MAP_LENGTH - 1) break;
rc = read(fd, buffer + bytes_read, 1);
if (rc < 1) break;
} while (buffer[bytes_read] != '\n');
buffer[bytes_read] = 0;
// Ignore mappings that are not executable.
if (buffer[3] != 'x') continue;
char* start_of_path = index(buffer, '/');
// There may be no filename in this line. Skip to next.
if (start_of_path == nullptr) continue;
buffer[bytes_read] = 0;
result.push_back(SharedLibraryAddress(start_of_path, start, end));
}
close(fd);
return result;
}
void OS::SignalCodeMovingGC() {}
void OS::AdjustSchedulingParams() {}
std::vector<OS::MemoryRange> OS::GetFreeMemoryRangesWithin(
OS::Address boundary_start, OS::Address boundary_end, size_t minimum_size,
size_t alignment) {
return {};
}
// static
Stack::StackSlot Stack::ObtainCurrentThreadStackStart() {
// pthread_getthrds_np creates 3 values:
// __pi_stackaddr, __pi_stacksize, __pi_stackend
// higher address ----- __pi_stackend, stack base
//
// |
// | __pi_stacksize, stack grows downwards
// |
// V
//
// lower address ----- __pi_stackaddr, current sp
pthread_t tid = pthread_self();
struct __pthrdsinfo buf;
// clear buf
memset(&buf, 0, sizeof(buf));
char regbuf[1];
int regbufsize = sizeof(regbuf);
const int rc = pthread_getthrds_np(&tid, PTHRDSINFO_QUERY_ALL, &buf,
sizeof(buf), regbuf, ®bufsize);
CHECK(!rc);
if (buf.__pi_stackend == NULL || buf.__pi_stackaddr == NULL) {
return nullptr;
}
return reinterpret_cast<void*>(buf.__pi_stackend);
}
// static
bool OS::DecommitPages(void* address, size_t size) {
// The difference between this implementation and the alternative under
// platform-posix.cc is that on AIX, calling mmap on a pre-designated address
// with MAP_FIXED will fail and return -1 unless the application has requested
// SPEC1170 compliant behaviour:
// https://www.ibm.com/docs/en/aix/7.3?topic=m-mmap-mmap64-subroutine
// Therefore in case if failure we need to unmap the address before trying to
// map it again. The downside is another thread could place another mapping at
// the same address after the munmap but before the mmap, therefore a CHECK is
// also added to assure the address is mapped successfully. Refer to the
// comments under https://crrev.com/c/3010195 for more details.
#define MMAP() \
mmap(address, size, PROT_NONE, MAP_FIXED | MAP_ANONYMOUS | MAP_PRIVATE, -1, 0)
DCHECK_EQ(0, reinterpret_cast<uintptr_t>(address) % CommitPageSize());
DCHECK_EQ(0, size % CommitPageSize());
void* ptr;
// Try without mapping first.
ptr = MMAP();
if (ptr != address) {
DCHECK_EQ(ptr, MAP_FAILED);
// Returns 0 when successful.
if (munmap(address, size)) {
return false;
}
// Try again after unmap.
ptr = MMAP();
// If this check fails it's most likely due to a racing condition where
// another thread has mapped the same address right before we do.
// Since this could cause hard-to-debug issues, potentially with security
// impact, and we can't recover from this, the best we can do is abort the
// process.
CHECK_EQ(ptr, address);
}
#undef MMAP
return true;
}
} // namespace base
} // namespace v8
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