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/* Copyright (C) 1993-2021 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
<https://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>
#include <shlib-compat.h>
FILE *
_IO_new_fdopen (int fd, const char *mode)
{
int read_write;
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 i;
int use_mmap = 0;
/* Decide whether we modify the offset of the file we attach to and seek to
the end of file. We only do this if the mode is 'a' and if the file
descriptor did not have O_APPEND in its flags already. */
bool do_seek = false;
switch (*mode)
{
case 'r':
read_write = _IO_NO_WRITES;
break;
case 'w':
read_write = _IO_NO_READS;
break;
case 'a':
read_write = _IO_NO_READS|_IO_IS_APPENDING;
break;
default:
__set_errno (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;
}
int fd_flags = __fcntl (fd, F_GETFL);
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)))
{
__set_errno (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 ((read_write & _IO_IS_APPENDING) && !(fd_flags & O_APPEND))
{
do_seek = true;
if (__fcntl (fd, F_SETFL, fd_flags | O_APPEND) == -1)
return NULL;
}
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,
#if _G_HAVE_MMAP
(use_mmap && (read_write & _IO_NO_WRITES))
? &_IO_wfile_jumps_maybe_mmap :
#endif
&_IO_wfile_jumps);
_IO_JUMPS (&new_f->fp) =
#if _G_HAVE_MMAP
(use_mmap && (read_write & _IO_NO_WRITES)) ? &_IO_file_jumps_maybe_mmap :
#endif
&_IO_file_jumps;
_IO_new_file_init_internal (&new_f->fp);
/* We only need to record the fd because _IO_file_init_internal 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 if we added
O_APPEND to the file descriptor flags. Don't update the offset cache
though, since the file handle is not active. */
if (do_seek && ((read_write & (_IO_IS_APPENDING | _IO_NO_READS))
== (_IO_IS_APPENDING | _IO_NO_READS)))
{
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);
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