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// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#ifndef PLATFORM_SIGNAL_BLOCKER_H_
#define PLATFORM_SIGNAL_BLOCKER_H_
#include "platform/globals.h"
#include "platform/assert.h"
#if defined(TARGET_OS_WINDOWS)
#error Do not include this file on Windows.
#endif
#include <pthread.h>
#include <signal.h> // NOLINT
namespace dart {
class ThreadSignalBlocker {
public:
explicit ThreadSignalBlocker(int sig) {
sigset_t signal_mask;
sigemptyset(&signal_mask);
sigaddset(&signal_mask, sig);
// Add sig to signal mask.
int r = pthread_sigmask(SIG_BLOCK, &signal_mask, &old);
USE(r);
ASSERT(r == 0);
}
ThreadSignalBlocker(int sigs_count, const int sigs[]) {
sigset_t signal_mask;
sigemptyset(&signal_mask);
for (int i = 0; i < sigs_count; i++) {
sigaddset(&signal_mask, sigs[i]);
}
// Add sig to signal mask.
int r = pthread_sigmask(SIG_BLOCK, &signal_mask, &old);
USE(r);
ASSERT(r == 0);
}
~ThreadSignalBlocker() {
// Restore signal mask.
int r = pthread_sigmask(SIG_SETMASK, &old, NULL);
USE(r);
ASSERT(r == 0);
}
private:
sigset_t old;
};
// The definition below is copied from Linux and adapted to avoid lint
// errors (type long int changed to intptr_t and do/while split on
// separate lines with body in {}s) and to also block signals.
#define TEMP_FAILURE_RETRY(expression) \
({ ThreadSignalBlocker tsb(SIGPROF); \
intptr_t __result; \
do { \
__result = (expression); \
} while ((__result == -1L) && (errno == EINTR)); \
__result; })
// This is a version of TEMP_FAILURE_RETRY which does not use the value
// returned from the expression.
#define VOID_TEMP_FAILURE_RETRY(expression) \
(static_cast<void>(TEMP_FAILURE_RETRY(expression)))
// This macro can be used to insert checks that a call is made, that
// was expected to not return EINTR, but did it anyway.
#define NO_RETRY_EXPECTED(expression) \
({ intptr_t __result = (expression); \
if (__result == -1L && errno == EINTR) { \
FATAL("Unexpected EINTR errno"); \
} \
__result; })
#define VOID_NO_RETRY_EXPECTED(expression) \
(static_cast<void>(NO_RETRY_EXPECTED(expression)))
// Define to check in debug mode, if a signal is currently being blocked.
#define CHECK_IS_BLOCKING(signal) \
({ sigset_t signal_mask; \
int __r = pthread_sigmask(SIG_BLOCK, NULL, &signal_mask); \
USE(__r); \
ASSERT(__r == 0); \
sigismember(&signal_mask, signal); }) \
// Versions of the above, that does not enter a signal blocking scope. Use only
// when a signal blocking scope is entered manually.
#define TEMP_FAILURE_RETRY_NO_SIGNAL_BLOCKER(expression) \
({ intptr_t __result; \
ASSERT(CHECK_IS_BLOCKING(SIGPROF)); \
do { \
__result = (expression); \
} while ((__result == -1L) && (errno == EINTR)); \
__result; })
#define VOID_TEMP_FAILURE_RETRY_NO_SIGNAL_BLOCKER(expression) \
(static_cast<void>(TEMP_FAILURE_RETRY_NO_SIGNAL_BLOCKER(expression)))
} // namespace dart
#endif // PLATFORM_SIGNAL_BLOCKER_H_