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  1. /* Implement fopen_unlocked and related functions.
  2.    Copyright (C) 2005, 2011 Free Software Foundation, Inc.
  3.    Written by Kaveh R. Ghazi <ghazi@caip.rutgers.edu>.
  4.  
  5. This file is part of the libiberty library.
  6. Libiberty is free software; you can redistribute it and/or
  7. modify it under the terms of the GNU Library General Public
  8. License as published by the Free Software Foundation; either
  9. version 2 of the License, or (at your option) any later version.
  10.  
  11. Libiberty is distributed in the hope that it will be useful,
  12. but WITHOUT ANY WARRANTY; without even the implied warranty of
  13. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14. Library General Public License for more details.
  15.  
  16. You should have received a copy of the GNU Library General Public
  17. License along with libiberty; see the file COPYING.LIB.  If
  18. not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
  19. Boston, MA 02110-1301, USA.  */
  20.  
  21. /*
  22.  
  23. @deftypefn Extension void unlock_stream (FILE * @var{stream})
  24.  
  25. If the OS supports it, ensure that the supplied stream is setup to
  26. avoid any multi-threaded locking.  Otherwise leave the @code{FILE}
  27. pointer unchanged.  If the @var{stream} is @code{NULL} do nothing.
  28.  
  29. @end deftypefn
  30.  
  31. @deftypefn Extension void unlock_std_streams (void)
  32.  
  33. If the OS supports it, ensure that the standard I/O streams,
  34. @code{stdin}, @code{stdout} and @code{stderr} are setup to avoid any
  35. multi-threaded locking.  Otherwise do nothing.
  36.  
  37. @end deftypefn
  38.  
  39. @deftypefn Extension {FILE *} fopen_unlocked (const char *@var{path}, @
  40.   const char * @var{mode})
  41.  
  42. Opens and returns a @code{FILE} pointer via @code{fopen}.  If the
  43. operating system supports it, ensure that the stream is setup to avoid
  44. any multi-threaded locking.  Otherwise return the @code{FILE} pointer
  45. unchanged.
  46.  
  47. @end deftypefn
  48.  
  49. @deftypefn Extension {FILE *} fdopen_unlocked (int @var{fildes}, @
  50.   const char * @var{mode})
  51.  
  52. Opens and returns a @code{FILE} pointer via @code{fdopen}.  If the
  53. operating system supports it, ensure that the stream is setup to avoid
  54. any multi-threaded locking.  Otherwise return the @code{FILE} pointer
  55. unchanged.
  56.  
  57. @end deftypefn
  58.  
  59. @deftypefn Extension {FILE *} freopen_unlocked (const char * @var{path}, @
  60.   const char * @var{mode}, FILE * @var{stream})
  61.  
  62. Opens and returns a @code{FILE} pointer via @code{freopen}.  If the
  63. operating system supports it, ensure that the stream is setup to avoid
  64. any multi-threaded locking.  Otherwise return the @code{FILE} pointer
  65. unchanged.
  66.  
  67. @end deftypefn
  68.  
  69. */
  70.  
  71. #ifdef HAVE_CONFIG_H
  72. #include "config.h"
  73. #endif
  74. #include <stdio.h>
  75. #ifdef HAVE_STDIO_EXT_H
  76. #include <stdio_ext.h>
  77. #endif
  78.  
  79. #include "libiberty.h"
  80.  
  81. /* This is an inline helper function to consolidate attempts to unlock
  82.    a stream.  */
  83.  
  84. static inline void
  85. unlock_1 (FILE *const fp ATTRIBUTE_UNUSED)
  86. {
  87. #if defined(HAVE___FSETLOCKING) && defined(FSETLOCKING_BYCALLER)
  88.   if (fp)
  89.     __fsetlocking (fp, FSETLOCKING_BYCALLER);
  90. #endif
  91. }
  92.  
  93. void
  94. unlock_stream (FILE *fp)
  95. {
  96.   unlock_1 (fp);
  97. }
  98.  
  99. void
  100. unlock_std_streams (void)
  101. {
  102.   unlock_1 (stdin);
  103.   unlock_1 (stdout);
  104.   unlock_1 (stderr);
  105. }
  106.  
  107. FILE *
  108. fopen_unlocked (const char *path, const char *mode)            
  109. {
  110.   FILE *const fp = fopen (path, mode);
  111.   unlock_1 (fp);
  112.   return fp;
  113. }
  114.  
  115. FILE *
  116. fdopen_unlocked (int fildes, const char *mode)
  117. {
  118.   FILE *const fp = fdopen (fildes, mode);
  119.   unlock_1 (fp);
  120.   return fp;
  121. }
  122.  
  123. FILE *
  124. freopen_unlocked (const char *path, const char *mode, FILE *stream)
  125. {
  126.   FILE *const fp = freopen (path, mode, stream);
  127.   unlock_1 (fp);
  128.   return fp;
  129. }
  130.