glibc/libio/iofdopen.c

181 lines
4.9 KiB
C

/* 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
/* Set up initially to use the `maybe_mmap' jump tables rather than using
__fopen_maybe_mmap to do it, because we need them in place before we
call _IO_file_attach or else it will allocate a buffer immediately. */
_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
if (_IO_file_attach ((_IO_FILE *) &new_f->fp, fd) == NULL)
{
_IO_setb (&new_f->fp.file, NULL, NULL, 0);
_IO_un_link (&new_f->fp);
free (new_f);
return NULL;
}
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);
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);