1// Copyright (c) 2012 The Chromium 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// This provides a wrapper around system calls which may be interrupted by a
6// signal and return EINTR. See man 7 signal.
7// To prevent long-lasting loops (which would likely be a bug, such as a signal
8// that should be masked) to go unnoticed, there is a limit after which the
9// caller will nonetheless see an EINTR in Debug builds.
10//
11// On Windows, this wrapper macro does nothing.
12//
13// Don't wrap close calls in HANDLE_EINTR. Use IGNORE_EINTR if the return
14// value of close is significant. See http://crbug.com/269623.
15
16#ifndef BASE_POSIX_EINTR_WRAPPER_H_
17#define BASE_POSIX_EINTR_WRAPPER_H_
18
19#include "build/build_config.h"
20
21#if defined(OS_POSIX)
22
23#include <errno.h>
24
25#if defined(NDEBUG)
26
27#define HANDLE_EINTR(x) ({ \
28  typeof(x) eintr_wrapper_result; \
29  do { \
30    eintr_wrapper_result = (x); \
31  } while (eintr_wrapper_result == -1 && errno == EINTR); \
32  eintr_wrapper_result; \
33})
34
35#else
36
37#define HANDLE_EINTR(x) ({ \
38  int eintr_wrapper_counter = 0; \
39  typeof(x) eintr_wrapper_result; \
40  do { \
41    eintr_wrapper_result = (x); \
42  } while (eintr_wrapper_result == -1 && errno == EINTR && \
43           eintr_wrapper_counter++ < 100); \
44  eintr_wrapper_result; \
45})
46
47#endif  // NDEBUG
48
49#define IGNORE_EINTR(x) ({ \
50  typeof(x) eintr_wrapper_result; \
51  do { \
52    eintr_wrapper_result = (x); \
53    if (eintr_wrapper_result == -1 && errno == EINTR) { \
54      eintr_wrapper_result = 0; \
55    } \
56  } while (0); \
57  eintr_wrapper_result; \
58})
59
60#else
61
62#define HANDLE_EINTR(x) (x)
63#define IGNORE_EINTR(x) (x)
64
65#endif  // OS_POSIX
66
67#endif  // BASE_POSIX_EINTR_WRAPPER_H_
68