libio/iofdopen.c

   1 /* Copyright (C) 1993, 1994, 1997-1999, 2000 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, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.
  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 #ifdef __STDC__
  29 # include <stdlib.h>
  30 #endif
  31 #include "libioP.h"
  32 #include <fcntl.h>
  33
  34 #ifdef _LIBC
  35 # include <shlib-compat.h>
  36 #endif
  37
  38 #ifndef _IO_fcntl
  39 #ifdef _LIBC
  40 #define _IO_fcntl __fcntl
  41 #else
  42 #define _IO_fcntl fcntl
  43 #endif
  44 #endif
  45
  46 _IO_FILE *
  47 _IO_new_fdopen (fd, mode)
  48      int fd;
  49      const char *mode;
  50 {
  51   int read_write;
  52   int posix_mode = 0;
  53   struct locked_FILE
  54   {
  55     struct _IO_FILE_plus fp;
  56 #ifdef _IO_MTSAFE_IO
  57     _IO_lock_t lock;
  58 #endif
  59     struct _IO_wide_data wd;
  60   } *new_f;
  61   int fd_flags;
  62
  63   switch (*mode++)
  64     {
  65     case 'r':
  66       read_write = _IO_NO_WRITES;
  67       break;
  68     case 'w':
  69       read_write = _IO_NO_READS;
  70       break;
  71     case 'a':
  72       posix_mode = O_APPEND;
  73       read_write = _IO_NO_READS|_IO_IS_APPENDING;
  74       break;
  75     default:
  76       MAYBE_SET_EINVAL;
  77       return NULL;
  78   }
  79   if (mode[0] == '+' || (mode[0] == 'b' && mode[1] == '+'))
  80     read_write &= _IO_IS_APPENDING;
  81 #ifdef F_GETFL
  82   fd_flags = _IO_fcntl (fd, F_GETFL);
  83 #ifndef O_ACCMODE
  84 #define O_ACCMODE (O_RDONLY|O_WRONLY|O_RDWR)
  85 #endif
  86   if (fd_flags == -1)
  87     return NULL;
  88
  89   if (((fd_flags & O_ACCMODE) == O_RDONLY && !(read_write & _IO_NO_WRITES))
  90       || ((fd_flags & O_ACCMODE) == O_WRONLY && !(read_write & _IO_NO_READS)))
  91     {
  92       MAYBE_SET_EINVAL;
  93       return NULL;
  94     }
  95
  96   /* The May 93 draft of P1003.4/D14.1 (redesignated as 1003.1b)
  97      [System Application Program Interface (API) Amendment 1:
  98      Realtime Extensions], Rationale B.8.3.3
  99      Open a Stream on a File Descriptor says:
 100
 101          Although not explicitly required by POSIX.1, a good
 102          implementation of append ("a") mode would cause the
 103          O_APPEND flag to be set.
 104
 105      (Historical implementations [such as Solaris2] do a one-time
 106      seek in fdopen.)
 107
 108      However, we do not turn O_APPEND off if the mode is "w" (even
 109      though that would seem consistent) because that would be more
 110      likely to break historical programs.
 111      */
 112   if ((posix_mode & O_APPEND) && !(fd_flags & O_APPEND))
 113     {
 114 #ifdef F_SETFL
 115       if (_IO_fcntl (fd, F_SETFL, fd_flags | O_APPEND) == -1)
 116 #endif
 117         return NULL;
 118     }
 119 #endif
 120
 121   new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
 122   if (new_f == NULL)
 123     return NULL;
 124 #ifdef _IO_MTSAFE_IO
 125   new_f->fp.file._lock = &new_f->lock;
 126 #endif
 127   _IO_no_init (&new_f->fp.file, 0, 0, &new_f->wd, &_IO_wfile_jumps);
 128   _IO_JUMPS (&new_f->fp) = &_IO_file_jumps;
 129   _IO_file_init (&new_f->fp);
 130 #if  !_IO_UNIFIED_JUMPTABLES
 131   new_f->fp.vtable = NULL;
 132 #endif
 133   if (_IO_file_attach ((_IO_FILE *) &new_f->fp, fd) == NULL)
 134     {
 135       _IO_un_link (&new_f->fp);
 136       free (new_f);
 137       return NULL;
 138     }
 139   new_f->fp.file._flags &= ~_IO_DELETE_DONT_CLOSE;
 140
 141   new_f->fp.file._IO_file_flags =
 142     _IO_mask_flags (&new_f->fp.file, read_write,
 143                     _IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);
 144
 145   return (_IO_FILE *) &new_f->fp;
 146 }
 147
 148 strong_alias (_IO_new_fdopen, __new_fdopen)
 149 versioned_symbol (libc, _IO_new_fdopen, _IO_fdopen, GLIBC_2_1);
 150 versioned_symbol (libc, __new_fdopen, fdopen, GLIBC_2_1);