base/posix/eintr_wrapper.h

   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 #ifndef BASE_POSIX_EINTR_WRAPPER_H_
  14 #define BASE_POSIX_EINTR_WRAPPER_H_
  15
  16 #include "build/build_config.h"
  17
  18 #if defined(OS_POSIX)
  19
  20 #include <errno.h>
  21
  22 #if defined(NDEBUG)
  23 #define HANDLE_EINTR(x) ({ \
  24   typeof(x) eintr_wrapper_result; \
  25   do { \
  26     eintr_wrapper_result = (x); \
  27   } while (eintr_wrapper_result == -1 && errno == EINTR); \
  28   eintr_wrapper_result; \
  29 })
  30
  31 #else
  32
  33 #define HANDLE_EINTR(x) ({ \
  34   int eintr_wrapper_counter = 0; \
  35   typeof(x) eintr_wrapper_result; \
  36   do { \
  37     eintr_wrapper_result = (x); \
  38   } while (eintr_wrapper_result == -1 && errno == EINTR && \
  39            eintr_wrapper_counter++ < 100); \
  40   eintr_wrapper_result; \
  41 })
  42
  43 #endif  // NDEBUG
  44
  45 #else
  46
  47 #define HANDLE_EINTR(x) (x)
  48
  49 #endif  // OS_POSIX
  50
  51 #endif  // BASE_POSIX_EINTR_WRAPPER_H_