1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42
   43
   44
   45
   46
   47
   48
   49
   50
   51
   52
   53
   54
   55
   56
   57
   58
   59
   60
   61
   62
   63
   64
   65
   66
   67
   68


base / posix / eintr_wrapper.h [blame]

// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// This provides a wrapper around system calls which may be interrupted by a
// signal and return EINTR. See man 7 signal.
// To prevent long-lasting loops (which would likely be a bug, such as a signal
// that should be masked) to go unnoticed, there is a limit after which the
// caller will nonetheless see an EINTR in Debug builds.
//
// On Windows and Fuchsia, this wrapper macro does nothing because there are no
// signals.
//
// Don't wrap close calls in HANDLE_EINTR. Use IGNORE_EINTR if the return
// value of close is significant. See http://crbug.com/269623.

#ifndef BASE_POSIX_EINTR_WRAPPER_H_
#define BASE_POSIX_EINTR_WRAPPER_H_

#include "build/build_config.h"

#if BUILDFLAG(IS_POSIX)

#include <errno.h>

#if defined(NDEBUG)

#define HANDLE_EINTR(x) ({ \
  decltype(x) eintr_wrapper_result; \
  do { \
    eintr_wrapper_result = (x); \
  } while (eintr_wrapper_result == -1 && errno == EINTR); \
  eintr_wrapper_result; \
})

#else

#define HANDLE_EINTR(x) ({ \
  int eintr_wrapper_counter = 0; \
  decltype(x) eintr_wrapper_result; \
  do { \
    eintr_wrapper_result = (x); \
  } while (eintr_wrapper_result == -1 && errno == EINTR && \
           eintr_wrapper_counter++ < 100); \
  eintr_wrapper_result; \
})

#endif  // NDEBUG

#define IGNORE_EINTR(x) ({ \
  decltype(x) eintr_wrapper_result; \
  do { \
    eintr_wrapper_result = (x); \
    if (eintr_wrapper_result == -1 && errno == EINTR) { \
      eintr_wrapper_result = 0; \
    } \
  } while (0); \
  eintr_wrapper_result; \
})

#else  // !BUILDFLAG(IS_POSIX)

#define HANDLE_EINTR(x) (x)
#define IGNORE_EINTR(x) (x)

#endif  // !BUILDFLAG(IS_POSIX)

#endif  // BASE_POSIX_EINTR_WRAPPER_H_