libio/oldiofdopen.c

   1 /* Copyright (C) 1993-2015 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    <http://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 #ifndef _IO_fcntl
  36 # define _IO_fcntl __fcntl
  37 #endif
  38
  39 _IO_FILE *
  40 attribute_compat_text_section
  41 _IO_old_fdopen (fd, mode)
  42      int fd;
  43      const char *mode;
  44 {
  45   int read_write;
  46   int posix_mode = 0;
  47   struct locked_FILE
  48   {
  49     struct _IO_FILE_complete_plus fp;
  50 #ifdef _IO_MTSAFE_IO
  51     _IO_lock_t lock;
  52 #endif
  53   } *new_f;
  54   int fd_flags;
  55
  56   switch (*mode++)
  57     {
  58     case 'r':
  59       read_write = _IO_NO_WRITES;
  60       break;
  61     case 'w':
  62       read_write = _IO_NO_READS;
  63       break;
  64     case 'a':
  65       posix_mode = O_APPEND;
  66       read_write = _IO_NO_READS|_IO_IS_APPENDING;
  67       break;
  68     default:
  69       MAYBE_SET_EINVAL;
  70       return NULL;
  71   }
  72   if (mode[0] == '+' || (mode[0] == 'b' && mode[1] == '+'))
  73     read_write &= _IO_IS_APPENDING;
  74 #ifdef F_GETFL
  75   fd_flags = _IO_fcntl (fd, F_GETFL);
  76 #ifndef O_ACCMODE
  77 #define O_ACCMODE (O_RDONLY|O_WRONLY|O_RDWR)
  78 #endif
  79   if (fd_flags == -1
  80       || ((fd_flags & O_ACCMODE) == O_RDONLY && !(read_write & _IO_NO_WRITES))
  81       || ((fd_flags & O_ACCMODE) == O_WRONLY && !(read_write & _IO_NO_READS)))
  82     return NULL;
  83
  84   /* The May 93 draft of P1003.4/D14.1 (redesignated as 1003.1b)
  85      [System Application Program Interface (API) Amendment 1:
  86      Realtime Extensions], Rationale B.8.3.3
  87      Open a Stream on a File Descriptor says:
  88
  89          Although not explicitly required by POSIX.1, a good
  90          implementation of append ("a") mode would cause the
  91          O_APPEND flag to be set.
  92
  93      (Historical implementations [such as Solaris2] do a one-time
  94      seek in fdopen.)
  95
  96      However, we do not turn O_APPEND off if the mode is "w" (even
  97      though that would seem consistent) because that would be more
  98      likely to break historical programs.
  99      */
 100   if ((posix_mode & O_APPEND) && !(fd_flags & O_APPEND))
 101     {
 102 #ifdef F_SETFL
 103       if (_IO_fcntl (fd, F_SETFL, fd_flags | O_APPEND) == -1)
 104 #endif
 105         return NULL;
 106     }
 107 #endif
 108
 109   new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
 110   if (new_f == NULL)
 111     return NULL;
 112 #ifdef _IO_MTSAFE_IO
 113   new_f->fp.file._file._lock = &new_f->lock;
 114 #endif
 115   _IO_old_init (&new_f->fp.file._file, 0);
 116   _IO_JUMPS_FILE_plus (&new_f->fp) = &_IO_old_file_jumps;
 117   _IO_old_file_init ((struct _IO_FILE_plus *) &new_f->fp);
 118 #if  !_IO_UNIFIED_JUMPTABLES
 119   new_f->fp.vtable = NULL;
 120 #endif
 121   if (_IO_old_file_attach (&new_f->fp.file._file, fd) == NULL)
 122     {
 123       _IO_un_link ((struct _IO_FILE_plus *) &new_f->fp);
 124       free (new_f);
 125       return NULL;
 126     }
 127   new_f->fp.file._file._flags &= ~_IO_DELETE_DONT_CLOSE;
 128
 129   _IO_mask_flags (&new_f->fp.file._file, read_write,
 130                   _IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);
 131
 132   return (_IO_FILE *) &new_f->fp;
 133 }
 134
 135 strong_alias (_IO_old_fdopen, __old_fdopen)
 136 compat_symbol (libc, _IO_old_fdopen, _IO_fdopen, GLIBC_2_0);
 137 compat_symbol (libc, __old_fdopen, fdopen, GLIBC_2_0);
 138
 139 #endif