libio/iofgetpos.c

   1 /* Copyright (C) 1993-2021 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.
  17
  18    As a special exception, if you link the code in this file with
  19    files compiled with a GNU compiler to produce an executable,
  20    that does not cause the resulting executable to be covered by
  21    the GNU Lesser General Public License.  This exception does not
  22    however invalidate any other reasons why the executable file
  23    might be covered by the GNU Lesser General Public License.
  24    This exception applies to code released by its copyright holders
  25    in files containing the exception.  */
  26
  27 /* We need to avoid the header declarations of these, because
  28    the types don't match _IO_fgetpos and then the compiler will
  29    complain about the mismatch when we do the alias below.  */
  30 #define _IO_new_fgetpos64 __renamed__IO_new_fgetpos64
  31 #define _IO_fgetpos64 __renamed__IO_fgetpos64
  32 #define fgetpos64 __renamed_fgetpos64
  33
  34 #include "libioP.h"
  35
  36 #undef _IO_new_fgetpos64
  37 #undef _IO_fgetpos64
  38 #undef fgetpos64
  39
  40 #include <errno.h>
  41 #include <stdlib.h>
  42 #include <shlib-compat.h>
  43
  44 int
  45 _IO_new_fgetpos (FILE *fp, __fpos_t *posp)
  46 {
  47   off64_t pos;
  48   int result = 0;
  49   CHECK_FILE (fp, EOF);
  50   _IO_acquire_lock (fp);
  51   pos = _IO_seekoff_unlocked (fp, 0, _IO_seek_cur, 0);
  52   if (_IO_in_backup (fp) && pos != _IO_pos_BAD)
  53     {
  54       if (fp->_mode <= 0)
  55         pos -= fp->_IO_save_end - fp->_IO_save_base;
  56     }
  57   if (pos == _IO_pos_BAD)
  58     {
  59       /* ANSI explicitly requires setting errno to a positive value on
  60          failure.  */
  61       if (errno == 0)
  62         __set_errno (EIO);
  63       result = EOF;
  64     }
  65   else if ((off64_t) (__typeof (posp->__pos)) pos != pos)
  66     {
  67       __set_errno (EOVERFLOW);
  68       result = EOF;
  69     }
  70   else
  71     {
  72       posp->__pos = pos;
  73       if (fp->_mode > 0 && __libio_codecvt_encoding (fp->_codecvt) < 0)
  74         /* This is a stateful encoding, safe the state.  */
  75         posp->__state = fp->_wide_data->_IO_state;
  76     }
  77
  78   _IO_release_lock (fp);
  79   return result;
  80 }
  81
  82 strong_alias (_IO_new_fgetpos, __new_fgetpos)
  83 versioned_symbol (libc, _IO_new_fgetpos, _IO_fgetpos, GLIBC_2_2);
  84 versioned_symbol (libc, __new_fgetpos, fgetpos, GLIBC_2_2);
  85
  86 #ifdef __OFF_T_MATCHES_OFF64_T
  87 strong_alias (_IO_new_fgetpos, _IO_new_fgetpos64)
  88 strong_alias (_IO_new_fgetpos64, __new_fgetpos64)
  89 versioned_symbol (libc, _IO_new_fgetpos64, _IO_fgetpos64, GLIBC_2_2);
  90 versioned_symbol (libc, __new_fgetpos64, fgetpos64, GLIBC_2_2);
  91 #endif