about summary refs log tree commit diff
path: root/libio/iofdopen.c
blob: 843a4fa65c773b21e079900093c68c611eb1b066 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
/* Copyright (C) 1993-2014 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.

   As a special exception, if you link the code in this file with
   files compiled with a GNU compiler to produce an executable,
   that does not cause the resulting executable to be covered by
   the GNU Lesser General Public License.  This exception does not
   however invalidate any other reasons why the executable file
   might be covered by the GNU Lesser General Public License.
   This exception applies to code released by its copyright holders
   in files containing the exception.  */

#include <stdlib.h>
#include "libioP.h"
#include <fcntl.h>

#ifdef _LIBC
# include <shlib-compat.h>
#endif

#ifndef _IO_fcntl
#ifdef _LIBC
#define _IO_fcntl __fcntl
#else
#define _IO_fcntl fcntl
#endif
#endif

_IO_FILE *
_IO_new_fdopen (fd, mode)
     int fd;
     const char *mode;
{
  int read_write;
  int posix_mode = 0;
  struct locked_FILE
  {
    struct _IO_FILE_plus fp;
#ifdef _IO_MTSAFE_IO
    _IO_lock_t lock;
#endif
    struct _IO_wide_data wd;
  } *new_f;
  int fd_flags;
  int i;
  int use_mmap = 0;

  switch (*mode)
    {
    case 'r':
      read_write = _IO_NO_WRITES;
      break;
    case 'w':
      read_write = _IO_NO_READS;
      break;
    case 'a':
      posix_mode = O_APPEND;
      read_write = _IO_NO_READS|_IO_IS_APPENDING;
      break;
    default:
      MAYBE_SET_EINVAL;
      return NULL;
  }
  for (i = 1; i < 5; ++i)
    {
      switch (*++mode)
	{
	case '\0':
	  break;
	case '+':
	  read_write &= _IO_IS_APPENDING;
	  break;
	case 'm':
	  use_mmap = 1;
	  continue;
	case 'x':
	case 'b':
	default:
	  /* Ignore */
	  continue;
	}
      break;
    }
#ifdef F_GETFL
  fd_flags = _IO_fcntl (fd, F_GETFL);
#ifndef O_ACCMODE
#define O_ACCMODE (O_RDONLY|O_WRONLY|O_RDWR)
#endif
  if (fd_flags == -1)
    return NULL;

  if (((fd_flags & O_ACCMODE) == O_RDONLY && !(read_write & _IO_NO_WRITES))
      || ((fd_flags & O_ACCMODE) == O_WRONLY && !(read_write & _IO_NO_READS)))
    {
      MAYBE_SET_EINVAL;
      return NULL;
    }

  /* The May 93 draft of P1003.4/D14.1 (redesignated as 1003.1b)
     [System Application Program Interface (API) Amendment 1:
     Realtime Extensions], Rationale B.8.3.3
     Open a Stream on a File Descriptor says:

         Although not explicitly required by POSIX.1, a good
         implementation of append ("a") mode would cause the
         O_APPEND flag to be set.

     (Historical implementations [such as Solaris2] do a one-time
     seek in fdopen.)

     However, we do not turn O_APPEND off if the mode is "w" (even
     though that would seem consistent) because that would be more
     likely to break historical programs.
     */
  if ((posix_mode & O_APPEND) && !(fd_flags & O_APPEND))
    {
#ifdef F_SETFL
      if (_IO_fcntl (fd, F_SETFL, fd_flags | O_APPEND) == -1)
#endif
	return NULL;
    }
#endif

  new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
  if (new_f == NULL)
    return NULL;
#ifdef _IO_MTSAFE_IO
  new_f->fp.file._lock = &new_f->lock;
#endif
  _IO_no_init (&new_f->fp.file, 0, 0, &new_f->wd,
#ifdef _G_HAVE_MMAP
	       (use_mmap && (read_write & _IO_NO_WRITES))
	       ? &_IO_wfile_jumps_maybe_mmap :
#endif
	       &_IO_wfile_jumps);
  _IO_JUMPS (&new_f->fp) =
#ifdef _G_HAVE_MMAP
    (use_mmap && (read_write & _IO_NO_WRITES)) ? &_IO_file_jumps_maybe_mmap :
#endif
      &_IO_file_jumps;
  _IO_file_init (&new_f->fp);
#if  !_IO_UNIFIED_JUMPTABLES
  new_f->fp.vtable = NULL;
#endif
  /* We only need to record the fd because _IO_file_init will have unset the
     offset.  It is important to unset the cached offset because the real
     offset in the file could change between now and when the handle is
     activated and we would then mislead ftell into believing that we have a
     valid offset.  */
  new_f->fp.file._fileno = fd;
  new_f->fp.file._flags &= ~_IO_DELETE_DONT_CLOSE;

  _IO_mask_flags (&new_f->fp.file, read_write,
		  _IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);

  /* For append mode, set the file offset to the end of the file.  Don't
     update the offset cache though, since the file handle is not active.  */
  if ((read_write & (_IO_IS_APPENDING | _IO_NO_READS))
      == (_IO_IS_APPENDING | _IO_NO_READS))
    {
      _IO_off64_t new_pos = _IO_SYSSEEK (&new_f->fp.file, 0, _IO_seek_end);
      if (new_pos == _IO_pos_BAD && errno != ESPIPE)
	return NULL;
    }
  return &new_f->fp.file;
}
libc_hidden_ver (_IO_new_fdopen, _IO_fdopen)

strong_alias (_IO_new_fdopen, __new_fdopen)
versioned_symbol (libc, _IO_new_fdopen, _IO_fdopen, GLIBC_2_1);
versioned_symbol (libc, __new_fdopen, fdopen, GLIBC_2_1);