src/system/libroot/posix/glibc/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
  29
  30 #include "libioP.h"
  31 #include <stdlib.h>
  32 #include <fcntl.h>
  33
  34 #ifdef _LIBC
  35 # include <shlib-compat.h>
  36 #endif
  37
  38
  39 _IO_FILE *
  40 _IO_new_fdopen (int fd, const char *mode)
  41 {
  42   int read_write;
  43   int posix_mode = 0;
  44   struct locked_FILE
  45   {
  46     struct _IO_FILE_plus fp;
  47 #ifdef _IO_MTSAFE_IO
  48     _IO_lock_t lock;
  49 #endif
  50     struct _IO_wide_data wd;
  51   } *new_f;
  52   int fd_flags;
  53   int i;
  54   int use_mmap = 0;
  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   for (i = 1; i < 5; ++i)
  73     {
  74       switch (*++mode)
  75         {
  76         case '\0':
  77           break;
  78         case '+':
  79           read_write &= _IO_IS_APPENDING;
  80           break;
  81         case 'm':
  82           use_mmap = 1;
  83           continue;
  84         case 'x':
  85         case 'b':
  86         default:
  87           /* Ignore */
  88           continue;
  89         }
  90       break;
  91     }
  92 #ifdef F_GETFL
  93   fd_flags = fcntl(fd, F_GETFL);
  94 #ifndef O_ACCMODE
  95 #define O_ACCMODE (O_RDONLY|O_WRONLY|O_RDWR)
  96 #endif
  97   if (fd_flags == -1)
  98     return NULL;
  99
 100   if (((fd_flags & O_ACCMODE) == O_RDONLY && !(read_write & _IO_NO_WRITES))
 101       || ((fd_flags & O_ACCMODE) == O_WRONLY && !(read_write & _IO_NO_READS)))
 102     {
 103       MAYBE_SET_EINVAL;
 104       return NULL;
 105     }
 106
 107   /* The May 93 draft of P1003.4/D14.1 (redesignated as 1003.1b)
 108      [System Application Program Interface (API) Amendment 1:
 109      Realtime Extensions], Rationale B.8.3.3
 110      Open a Stream on a File Descriptor says:
 111
 112          Although not explicitly required by POSIX.1, a good
 113          implementation of append ("a") mode would cause the
 114          O_APPEND flag to be set.
 115
 116      (Historical implementations [such as Solaris2] do a one-time
 117      seek in fdopen.)
 118
 119      However, we do not turn O_APPEND off if the mode is "w" (even
 120      though that would seem consistent) because that would be more
 121      likely to break historical programs.
 122      */
 123   if ((posix_mode & O_APPEND) && !(fd_flags & O_APPEND))
 124     {
 125 #ifdef F_SETFL
 126       if (fcntl(fd, F_SETFL, fd_flags | O_APPEND) == -1)
 127 #endif
 128         return NULL;
 129     }
 130 #endif
 131
 132   new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
 133   if (new_f == NULL)
 134     return NULL;
 135 #ifdef _IO_MTSAFE_IO
 136   new_f->fp.file._lock = &new_f->lock;
 137 #endif
 138   /* Set up initially to use the `maybe_mmap' jump tables rather than using
 139      __fopen_maybe_mmap to do it, because we need them in place before we
 140      call _IO_file_attach or else it will allocate a buffer immediately.  */
 141   _IO_no_init (&new_f->fp.file, 0, 0, &new_f->wd,
 142 #ifdef _G_HAVE_MMAP
 143                (use_mmap && (read_write & _IO_NO_WRITES))
 144                ? &_IO_wfile_jumps_maybe_mmap :
 145 #endif
 146                &INTUSE(_IO_wfile_jumps));
 147   _IO_JUMPS (&new_f->fp) =
 148 #ifdef _G_HAVE_MMAP
 149     (use_mmap && (read_write & _IO_NO_WRITES)) ? &_IO_file_jumps_maybe_mmap :
 150 #endif
 151       &INTUSE(_IO_file_jumps);
 152   INTUSE(_IO_file_init) (&new_f->fp);
 153 #if  !_IO_UNIFIED_JUMPTABLES
 154   new_f->fp.vtable = NULL;
 155 #endif
 156   if (INTUSE(_IO_file_attach) ((_IO_FILE *) &new_f->fp, fd) == NULL)
 157     {
 158       INTUSE(_IO_setb) (&new_f->fp.file, NULL, NULL, 0);
 159       INTUSE(_IO_un_link) (&new_f->fp);
 160       free (new_f);
 161       return NULL;
 162     }
 163   new_f->fp.file._flags &= ~_IO_DELETE_DONT_CLOSE;
 164
 165   new_f->fp.file._IO_file_flags =
 166     _IO_mask_flags (&new_f->fp.file, read_write,
 167                     _IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);
 168
 169   return &new_f->fp.file;
 170 }
 171 INTDEF2(_IO_new_fdopen, _IO_fdopen)
 172
 173 strong_alias (_IO_new_fdopen, __new_fdopen)
 174 versioned_symbol (libc, _IO_new_fdopen, _IO_fdopen, GLIBC_2_1);
 175 versioned_symbol (libc, __new_fdopen, fdopen, GLIBC_2_1);