libio/oldiofdopen.c

   1 /* Copyright (C) 1993,94,97,99,2000,2002,2003,2004,2012
   2    Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library 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 GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.
  18
  19    As a special exception, if you link the code in this file with
  20    files compiled with a GNU compiler to produce an executable,
  21    that does not cause the resulting executable to be covered by
  22    the GNU Lesser General Public License.  This exception does not
  23    however invalidate any other reasons why the executable file
  24    might be covered by the GNU Lesser General Public License.
  25    This exception applies to code released by its copyright holders
  26    in files containing the exception.  */
  27
  28 #include <shlib-compat.h>
  29 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
  30
  31 #define _IO_USE_OLD_IO_FILE
  32 #include <stdlib.h>
  33 #include "libioP.h"
  34 #include <fcntl.h>
  35
  36 #ifndef _IO_fcntl
  37 # define _IO_fcntl __fcntl
  38 #endif
  39
  40 _IO_FILE *
  41 attribute_compat_text_section
  42 _IO_old_fdopen (fd, mode)
  43      int fd;
  44      const char *mode;
  45 {
  46   int read_write;
  47   int posix_mode = 0;
  48   struct locked_FILE
  49   {
  50     struct _IO_FILE_complete_plus fp;
  51 #ifdef _IO_MTSAFE_IO
  52     _IO_lock_t lock;
  53 #endif
  54   } *new_f;
  55   int fd_flags;
  56
  57   switch (*mode++)
  58     {
  59     case 'r':
  60       read_write = _IO_NO_WRITES;
  61       break;
  62     case 'w':
  63       read_write = _IO_NO_READS;
  64       break;
  65     case 'a':
  66       posix_mode = O_APPEND;
  67       read_write = _IO_NO_READS|_IO_IS_APPENDING;
  68       break;
  69     default:
  70       MAYBE_SET_EINVAL;
  71       return NULL;
  72   }
  73   if (mode[0] == '+' || (mode[0] == 'b' && mode[1] == '+'))
  74     read_write &= _IO_IS_APPENDING;
  75 #ifdef F_GETFL
  76   fd_flags = _IO_fcntl (fd, F_GETFL);
  77 #ifndef O_ACCMODE
  78 #define O_ACCMODE (O_RDONLY|O_WRONLY|O_RDWR)
  79 #endif
  80   if (fd_flags == -1
  81       || ((fd_flags & O_ACCMODE) == O_RDONLY && !(read_write & _IO_NO_WRITES))
  82       || ((fd_flags & O_ACCMODE) == O_WRONLY && !(read_write & _IO_NO_READS)))
  83     return NULL;
  84
  85   /* The May 93 draft of P1003.4/D14.1 (redesignated as 1003.1b)
  86      [System Application Program Interface (API) Amendment 1:
  87      Realtime Extensions], Rationale B.8.3.3
  88      Open a Stream on a File Descriptor says:
  89
  90          Although not explicitly required by POSIX.1, a good
  91          implementation of append ("a") mode would cause the
  92          O_APPEND flag to be set.
  93
  94      (Historical implementations [such as Solaris2] do a one-time
  95      seek in fdopen.)
  96
  97      However, we do not turn O_APPEND off if the mode is "w" (even
  98      though that would seem consistent) because that would be more
  99      likely to break historical programs.
 100      */
 101   if ((posix_mode & O_APPEND) && !(fd_flags & O_APPEND))
 102     {
 103 #ifdef F_SETFL
 104       if (_IO_fcntl (fd, F_SETFL, fd_flags | O_APPEND) == -1)
 105 #endif
 106         return NULL;
 107     }
 108 #endif
 109
 110   new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
 111   if (new_f == NULL)
 112     return NULL;
 113 #ifdef _IO_MTSAFE_IO
 114   new_f->fp.file._file._lock = &new_f->lock;
 115 #endif
 116   _IO_old_init (&new_f->fp.file._file, 0);
 117   _IO_JUMPS ((struct _IO_FILE_plus *) &new_f->fp) = &_IO_old_file_jumps;
 118   _IO_old_file_init ((struct _IO_FILE_plus *) &new_f->fp);
 119 #if  !_IO_UNIFIED_JUMPTABLES
 120   new_f->fp.vtable = NULL;
 121 #endif
 122   if (_IO_old_file_attach (&new_f->fp.file._file, fd) == NULL)
 123     {
 124       INTUSE(_IO_un_link) ((struct _IO_FILE_plus *) &new_f->fp);
 125       free (new_f);
 126       return NULL;
 127     }
 128   new_f->fp.file._file._flags &= ~_IO_DELETE_DONT_CLOSE;
 129
 130   _IO_mask_flags (&new_f->fp.file._file, read_write,
 131                   _IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);
 132
 133   return (_IO_FILE *) &new_f->fp;
 134 }
 135
 136 strong_alias (_IO_old_fdopen, __old_fdopen)
 137 compat_symbol (libc, _IO_old_fdopen, _IO_fdopen, GLIBC_2_0);
 138 compat_symbol (libc, __old_fdopen, fdopen, GLIBC_2_0);
 139
 140 #endif