1  /* Copyright (C) 1993-2023 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  #include <shlib-compat.h>
      28  #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
      29  
      30  #define _IO_USE_OLD_IO_FILE
      31  #include <stdlib.h>
      32  #include "libioP.h"
      33  #include <fcntl.h>
      34  
      35  FILE *
      36  attribute_compat_text_section
      37  _IO_old_fdopen (int fd, const char *mode)
      38  {
      39    int read_write;
      40    int posix_mode = 0;
      41    struct locked_FILE
      42    {
      43      struct _IO_FILE_complete_plus fp;
      44  #ifdef _IO_MTSAFE_IO
      45      _IO_lock_t lock;
      46  #endif
      47    } *new_f;
      48    int fd_flags;
      49  
      50    switch (*mode++)
      51      {
      52      case 'r':
      53        read_write = _IO_NO_WRITES;
      54        break;
      55      case 'w':
      56        read_write = _IO_NO_READS;
      57        break;
      58      case 'a':
      59        posix_mode = O_APPEND;
      60        read_write = _IO_NO_READS|_IO_IS_APPENDING;
      61        break;
      62      default:
      63        __set_errno (EINVAL);
      64        return NULL;
      65    }
      66    if (mode[0] == '+' || (mode[0] == 'b' && mode[1] == '+'))
      67      read_write &= _IO_IS_APPENDING;
      68    fd_flags = __fcntl (fd, F_GETFL);
      69    if (fd_flags == -1
      70        || ((fd_flags & O_ACCMODE) == O_RDONLY && !(read_write & _IO_NO_WRITES))
      71        || ((fd_flags & O_ACCMODE) == O_WRONLY && !(read_write & _IO_NO_READS)))
      72      return NULL;
      73  
      74    /* The May 93 draft of P1003.4/D14.1 (redesignated as 1003.1b)
      75       [System Application Program Interface (API) Amendment 1:
      76       Realtime Extensions], Rationale B.8.3.3
      77       Open a Stream on a File Descriptor says:
      78  
      79           Although not explicitly required by POSIX.1, a good
      80           implementation of append ("a") mode would cause the
      81           O_APPEND flag to be set.
      82  
      83       (Historical implementations [such as Solaris2] do a one-time
      84       seek in fdopen.)
      85  
      86       However, we do not turn O_APPEND off if the mode is "w" (even
      87       though that would seem consistent) because that would be more
      88       likely to break historical programs.
      89       */
      90    if ((posix_mode & O_APPEND) && !(fd_flags & O_APPEND))
      91      {
      92        if (__fcntl (fd, F_SETFL, fd_flags | O_APPEND) == -1)
      93  	return NULL;
      94      }
      95  
      96    new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
      97    if (new_f == NULL)
      98      return NULL;
      99  #ifdef _IO_MTSAFE_IO
     100    new_f->fp.file._file._lock = &new_f->lock;
     101  #endif
     102    _IO_old_init (&new_f->fp.file._file, 0);
     103    _IO_JUMPS_FILE_plus (&new_f->fp) = &_IO_old_file_jumps;
     104    _IO_old_file_init_internal ((struct _IO_FILE_plus *) &new_f->fp);
     105    if (_IO_old_file_attach (&new_f->fp.file._file, fd) == NULL)
     106      {
     107        _IO_un_link ((struct _IO_FILE_plus *) &new_f->fp);
     108        free (new_f);
     109        return NULL;
     110      }
     111    new_f->fp.file._file._flags &= ~_IO_DELETE_DONT_CLOSE;
     112  
     113    _IO_mask_flags (&new_f->fp.file._file, read_write,
     114  		  _IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);
     115  
     116    return (FILE *) &new_f->fp;
     117  }
     118  
     119  strong_alias (_IO_old_fdopen, __old_fdopen)
     120  compat_symbol (libc, _IO_old_fdopen, _IO_fdopen, GLIBC_2_0);
     121  compat_symbol (libc, __old_fdopen, fdopen, GLIBC_2_0);
     122  
     123  #endif