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0b727ed4d6
As POSIX states [1] a freopen call should first flush the stream as if by a
call fflush. C99 (n1256) and C11 (n1570) only states the function should
first close any file associated with the specific stream. Although current
implementation only follow C specification, current BSD and other libc
implementation (musl) are in sync with POSIX and fflush the stream.
This patch change freopen{64} to fflush the stream before actually reopening
it (or returning if the stream does not support reopen). It also changes the
Linux implementation to avoid a dynamic allocation on 'fd_to_filename'.
Checked on x86_64-linux-gnu.
[BZ #21037]
* libio/Makefile (tests): Add tst-memstream4 and tst-wmemstream4.
* libio/freopen.c (freopen): Sync stream before reopen and adjust to
new fd_to_filename interface.
* libio/freopen64.c (freopen64): Likewise.
* libio/tst-memstream.h: New file.
* libio/tst-memstream4.c: Likewise.
* libio/tst-wmemstream4.c: Likewise.
* sysdeps/generic/fd_to_filename.h (fd_to_filename): Change signature.
* sysdeps/unix/sysv/linux/fd_to_filename.h (fd_to_filename): Likewise
and remove internal dynamic allocation.
[1] http://pubs.opengroup.org/onlinepubs/9699919799/
96 lines
3.1 KiB
C
96 lines
3.1 KiB
C
/* Copyright (C) 1993-2018 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>.
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As a special exception, if you link the code in this file with
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files compiled with a GNU compiler to produce an executable,
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that does not cause the resulting executable to be covered by
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the GNU Lesser General Public License. This exception does not
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however invalidate any other reasons why the executable file
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might be covered by the GNU Lesser General Public License.
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This exception applies to code released by its copyright holders
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in files containing the exception. */
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#include <stdio.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <libioP.h>
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#include <fd_to_filename.h>
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FILE *
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freopen64 (const char *filename, const char *mode, FILE *fp)
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{
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FILE *result = NULL;
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char fdfilename[FD_TO_FILENAME_SIZE];
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CHECK_FILE (fp, NULL);
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_IO_acquire_lock (fp);
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/* First flush the stream (failure should be ignored). */
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_IO_SYNC (fp);
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if (!(fp->_flags & _IO_IS_FILEBUF))
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goto end;
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int fd = _IO_fileno (fp);
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const char *gfilename
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= filename != NULL ? filename : fd_to_filename (fd, fdfilename);
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fp->_flags2 |= _IO_FLAGS2_NOCLOSE;
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_IO_file_close_it (fp);
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_IO_JUMPS_FILE_plus (fp) = &_IO_file_jumps;
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if (_IO_vtable_offset (fp) == 0 && fp->_wide_data != NULL)
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fp->_wide_data->_wide_vtable = &_IO_wfile_jumps;
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result = _IO_file_fopen (fp, gfilename, mode, 0);
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fp->_flags2 &= ~_IO_FLAGS2_NOCLOSE;
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if (result != NULL)
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result = __fopen_maybe_mmap (result);
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if (result != NULL)
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{
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/* unbound stream orientation */
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result->_mode = 0;
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if (fd != -1 && _IO_fileno (result) != fd)
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{
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/* At this point we have both file descriptors already allocated,
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so __dup3 will not fail with EBADF, EINVAL, or EMFILE. But
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we still need to check for EINVAL and, due Linux internal
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implementation, EBUSY. It is because on how it internally opens
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the file by splitting the buffer allocation operation and VFS
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opening (a dup operation may run when a file is still pending
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'install' on VFS). */
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if (__dup3 (_IO_fileno (result), fd,
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(result->_flags2 & _IO_FLAGS2_CLOEXEC) != 0
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? O_CLOEXEC : 0) == -1)
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{
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_IO_file_close_it (result);
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result = NULL;
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goto end;
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}
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__close (_IO_fileno (result));
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_IO_fileno (result) = fd;
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}
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}
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else if (fd != -1)
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__close (fd);
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end:
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_IO_release_lock (fp);
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return result;
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}
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