lib/dup.c

   1 /* Duplicate an open file descriptor.
   2
   3    Copyright (C) 2011-2018 Free Software Foundation, Inc.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 #include <config.h>
  19
  20 /* Specification.  */
  21 #include <unistd.h>
  22
  23 #include <errno.h>
  24
  25 #if HAVE_MSVC_INVALID_PARAMETER_HANDLER
  26 # include "msvc-inval.h"
  27 #endif
  28
  29 #undef dup
  30
  31 #if HAVE_MSVC_INVALID_PARAMETER_HANDLER
  32 static int
  33 dup_nothrow (int fd)
  34 {
  35   int result;
  36
  37   TRY_MSVC_INVAL
  38     {
  39       result = dup (fd);
  40     }
  41   CATCH_MSVC_INVAL
  42     {
  43       result = -1;
  44       errno = EBADF;
  45     }
  46   DONE_MSVC_INVAL;
  47
  48   return result;
  49 }
  50 #elif defined __KLIBC__
  51 # include <fcntl.h>
  52 # include <sys/stat.h>
  53
  54 # include <InnoTekLIBC/backend.h>
  55
  56 static int
  57 dup_nothrow (int fd)
  58 {
  59   int dupfd;
  60   struct stat sbuf;
  61
  62   dupfd = dup (fd);
  63   if (dupfd == -1 && errno == ENOTSUP \
  64       && !fstat (fd, &sbuf) && S_ISDIR (sbuf.st_mode))
  65     {
  66       char path[_MAX_PATH];
  67
  68       /* Get a path from fd */
  69       if (!__libc_Back_ioFHToPath (fd, path, sizeof (path)))
  70         dupfd = open (path, O_RDONLY);
  71     }
  72
  73   return dupfd;
  74 }
  75 #else
  76 # define dup_nothrow dup
  77 #endif
  78
  79 int
  80 rpl_dup (int fd)
  81 {
  82   int result = dup_nothrow (fd);
  83 #if REPLACE_FCHDIR
  84   if (result >= 0)
  85     result = _gl_register_dup (fd, result);
  86 #endif
  87   return result;
  88 }