u-tools/apps/tar/gnu/dup2.c

   1 /* -*- buffer-read-only: t -*- vi: set ro: */
   2 /* DO NOT EDIT! GENERATED AUTOMATICALLY! */
   3 /* Duplicate an open file descriptor to a specified file descriptor.
   4
   5    Copyright (C) 1999, 2004-2007, 2009-2011 Free Software Foundation, Inc.
   6
   7    This program is free software: you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 /* written by Paul Eggert */
  21
  22 #include <config.h>
  23
  24 /* Specification.  */
  25 #include <unistd.h>
  26
  27 #include <errno.h>
  28 #include <fcntl.h>
  29
  30 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
  31 /* Get declarations of the Win32 API functions.  */
  32 # define WIN32_LEAN_AND_MEAN
  33 # include <windows.h>
  34 #endif
  35
  36 #if HAVE_DUP2
  37
  38 # undef dup2
  39
  40 int
  41 rpl_dup2 (int fd, int desired_fd)
  42 {
  43   int result;
  44 # if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
  45   /* If fd is closed, mingw hangs on dup2 (fd, fd).  If fd is open,
  46      dup2 (fd, fd) returns 0, but all further attempts to use fd in
  47      future dup2 calls will hang.  */
  48   if (fd == desired_fd)
  49     {
  50       if ((HANDLE) _get_osfhandle (fd) == INVALID_HANDLE_VALUE)
  51         {
  52           errno = EBADF;
  53           return -1;
  54         }
  55       return fd;
  56     }
  57   /* Wine 1.0.1 return 0 when desired_fd is negative but not -1:
  58      http://bugs.winehq.org/show_bug.cgi?id=21289 */
  59   if (desired_fd < 0)
  60     {
  61       errno = EBADF;
  62       return -1;
  63     }
  64 # elif !defined __linux__
  65   /* On Haiku, dup2 (fd, fd) mistakenly clears FD_CLOEXEC.  */
  66   if (fd == desired_fd)
  67     return fcntl (fd, F_GETFL) == -1 ? -1 : fd;
  68 # endif
  69   result = dup2 (fd, desired_fd);
  70 # ifdef __linux__
  71   /* Correct a Linux return value.
  72      <http://git.kernel.org/?p=linux/kernel/git/stable/linux-2.6.30.y.git;a=commitdiff;h=2b79bc4f7ebbd5af3c8b867968f9f15602d5f802>
  73    */
  74   if (fd == desired_fd && result == (unsigned int) -EBADF)
  75     {
  76       errno = EBADF;
  77       result = -1;
  78     }
  79 # endif
  80   if (result == 0)
  81     result = desired_fd;
  82   /* Correct a cygwin 1.5.x errno value.  */
  83   else if (result == -1 && errno == EMFILE)
  84     errno = EBADF;
  85 # if REPLACE_FCHDIR
  86   if (fd != desired_fd && result != -1)
  87     result = _gl_register_dup (fd, result);
  88 # endif
  89   return result;
  90 }
  91
  92 #else /* !HAVE_DUP2 */
  93
  94 /* On older platforms, dup2 did not exist.  */
  95
  96 # ifndef F_DUPFD
  97 static int
  98 dupfd (int fd, int desired_fd)
  99 {
 100   int duplicated_fd = dup (fd);
 101   if (duplicated_fd < 0 || duplicated_fd == desired_fd)
 102     return duplicated_fd;
 103   else
 104     {
 105       int r = dupfd (fd, desired_fd);
 106       int e = errno;
 107       close (duplicated_fd);
 108       errno = e;
 109       return r;
 110     }
 111 }
 112 # endif
 113
 114 int
 115 dup2 (int fd, int desired_fd)
 116 {
 117   int result = fcntl (fd, F_GETFL) < 0 ? -1 : fd;
 118   if (result == -1 || fd == desired_fd)
 119     return result;
 120   close (desired_fd);
 121 # ifdef F_DUPFD
 122   result = fcntl (fd, F_DUPFD, desired_fd);
 123 #  if REPLACE_FCHDIR
 124   if (0 <= result)
 125     result = _gl_register_dup (fd, result);
 126 #  endif
 127 # else
 128   result = dupfd (fd, desired_fd);
 129 # endif
 130   if (result == -1 && (errno == EMFILE || errno == EINVAL))
 131     errno = EBADF;
 132   return result;
 133 }
 134 #endif /* !HAVE_DUP2 */