libio/iofdopen.c

   1 /* Copyright (C) 1993,1994,1997-1999,2000,2002 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   int i;
  63   int use_mmap = 0;
  64
  65   switch (*mode)
  66     {
  67     case 'r':
  68       read_write = _IO_NO_WRITES;
  69       break;
  70     case 'w':
  71       read_write = _IO_NO_READS;
  72       break;
  73     case 'a':
  74       posix_mode = O_APPEND;
  75       read_write = _IO_NO_READS|_IO_IS_APPENDING;
  76       break;
  77     default:
  78       MAYBE_SET_EINVAL;
  79       return NULL;
  80   }
  81   for (i = 1; i < 5; ++i)
  82     {
  83       switch (*++mode)
  84         {
  85         case '\0':
  86           break;
  87         case '+':
  88           read_write &= _IO_IS_APPENDING;
  89           break;
  90         case 'm':
  91           use_mmap = 1;
  92           continue;
  93         case 'x':
  94         case 'b':
  95         default:
  96           /* Ignore */
  97           continue;
  98         }
  99       break;
 100     }
 101 #ifdef F_GETFL
 102   fd_flags = _IO_fcntl (fd, F_GETFL);
 103 #ifndef O_ACCMODE
 104 #define O_ACCMODE (O_RDONLY|O_WRONLY|O_RDWR)
 105 #endif
 106   if (fd_flags == -1)
 107     return NULL;
 108
 109   if (((fd_flags & O_ACCMODE) == O_RDONLY && !(read_write & _IO_NO_WRITES))
 110       || ((fd_flags & O_ACCMODE) == O_WRONLY && !(read_write & _IO_NO_READS)))
 111     {
 112       MAYBE_SET_EINVAL;
 113       return NULL;
 114     }
 115
 116   /* The May 93 draft of P1003.4/D14.1 (redesignated as 1003.1b)
 117      [System Application Program Interface (API) Amendment 1:
 118      Realtime Extensions], Rationale B.8.3.3
 119      Open a Stream on a File Descriptor says:
 120
 121          Although not explicitly required by POSIX.1, a good
 122          implementation of append ("a") mode would cause the
 123          O_APPEND flag to be set.
 124
 125      (Historical implementations [such as Solaris2] do a one-time
 126      seek in fdopen.)
 127
 128      However, we do not turn O_APPEND off if the mode is "w" (even
 129      though that would seem consistent) because that would be more
 130      likely to break historical programs.
 131      */
 132   if ((posix_mode & O_APPEND) && !(fd_flags & O_APPEND))
 133     {
 134 #ifdef F_SETFL
 135       if (_IO_fcntl (fd, F_SETFL, fd_flags | O_APPEND) == -1)
 136 #endif
 137         return NULL;
 138     }
 139 #endif
 140
 141   new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
 142   if (new_f == NULL)
 143     return NULL;
 144 #ifdef _IO_MTSAFE_IO
 145   new_f->fp.file._lock = &new_f->lock;
 146 #endif
 147   /* Set up initially to use the `maybe_mmap' jump tables rather than using
 148      __fopen_maybe_mmap to do it, because we need them in place before we
 149      call _IO_file_attach or else it will allocate a buffer immediately.  */
 150   _IO_no_init (&new_f->fp.file, 0, 0, &new_f->wd,
 151 #ifdef _G_HAVE_MMAP
 152                (use_mmap && (read_write & _IO_NO_WRITES))
 153                ? &_IO_wfile_jumps_maybe_mmap :
 154 #endif
 155                &INTUSE(_IO_wfile_jumps));
 156   _IO_JUMPS (&new_f->fp) =
 157 #ifdef _G_HAVE_MMAP
 158     (use_mmap && (read_write & _IO_NO_WRITES)) ? &_IO_file_jumps_maybe_mmap :
 159 #endif
 160       &INTUSE(_IO_file_jumps);
 161   INTUSE(_IO_file_init) (&new_f->fp);
 162 #if  !_IO_UNIFIED_JUMPTABLES
 163   new_f->fp.vtable = NULL;
 164 #endif
 165   if (INTUSE(_IO_file_attach) ((_IO_FILE *) &new_f->fp, fd) == NULL)
 166     {
 167       INTUSE(_IO_setb) (&new_f->fp.file, NULL, NULL, 0);
 168       INTUSE(_IO_un_link) (&new_f->fp);
 169       free (new_f);
 170       return NULL;
 171     }
 172   new_f->fp.file._flags &= ~_IO_DELETE_DONT_CLOSE;
 173
 174   new_f->fp.file._IO_file_flags =
 175     _IO_mask_flags (&new_f->fp.file, read_write,
 176                     _IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);
 177
 178   return &new_f->fp.file;
 179 }
 180 INTDEF2(_IO_new_fdopen, _IO_fdopen)
 181
 182 strong_alias (_IO_new_fdopen, __new_fdopen)
 183 versioned_symbol (libc, _IO_new_fdopen, _IO_fdopen, GLIBC_2_1);
 184 versioned_symbol (libc, __new_fdopen, fdopen, GLIBC_2_1);