glibc/libio/oldfileops.c
Zack Weinberg 2cc7bad0ae [BZ 1190] Make EOF sticky in stdio.
C99 specifies that the EOF condition on a file is "sticky": once EOF
has been encountered, all subsequent reads should continue to return
EOF until the file is closed or something clears the "end-of-file
indicator" (e.g. fseek, clearerr).  This is arguably a change from
C89, where the wording was ambiguous; the BSDs always had sticky EOF,
but the System V lineage would attempt to read from the underlying fd
again.  GNU libc has followed System V for as long as we've been
using libio, but nowadays C99 conformance and BSD compatibility are
more important than System V compatibility.

You might wonder if changing the _underflow impls is sufficient to
apply the C99 semantics to all of the many stdio functions that
perform input.  It should be enough to cover all paths to _IO_SYSREAD,
and the only other functions that call _IO_SYSREAD are the _seekoff
impls, which is OK because seeking clears EOF, and the _xsgetn impls,
which, as far as I can tell, are unused within glibc.

The test programs in this patch use a pseudoterminal to set up the
necessary conditions.  To facilitate this I added a new test-support
function that sets up a pair of pty file descriptors for you; it's
almost the same as BSD openpty, the only differences are that it
allocates the optionally-returned tty pathname with malloc, and that
it crashes if anything goes wrong.

	[BZ #1190]
        [BZ #19476]
	* libio/fileops.c (_IO_new_file_underflow): Return EOF immediately
	if the _IO_EOF_SEEN bit is already set; update commentary.
	* libio/oldfileops.c (_IO_old_file_underflow): Likewise.
	* libio/wfileops.c (_IO_wfile_underflow): Likewise.

	* support/support_openpty.c, support/tty.h: New files.
	* support/Makefile (libsupport-routines): Add support_openpty.

	* libio/tst-fgetc-after-eof.c, wcsmbs/test-fgetwc-after-eof.c:
	New test cases.
	* libio/Makefile (tests): Add tst-fgetc-after-eof.
	* wcsmbs/Makefile (tests): Add tst-fgetwc-after-eof.
2018-03-13 08:31:56 -04:00

761 lines
23 KiB
C

/* Copyright (C) 1993-2018 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Written by Per Bothner <bothner@cygnus.com>.
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. */
/* This is a compatibility file. If we don't build the libc with
versioning don't compile this file. */
#include <shlib-compat.h>
#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
#define _IO_USE_OLD_IO_FILE
#include "libioP.h"
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
/* An fstream can be in at most one of put mode, get mode, or putback mode.
Putback mode is a variant of get mode.
In a filebuf, there is only one current position, instead of two
separate get and put pointers. In get mode, the current position
is that of gptr(); in put mode that of pptr().
The position in the buffer that corresponds to the position
in external file system is normally _IO_read_end, except in putback
mode, when it is _IO_save_end.
If the field _fb._offset is >= 0, it gives the offset in
the file as a whole corresponding to eGptr(). (?)
PUT MODE:
If a filebuf is in put mode, then all of _IO_read_ptr, _IO_read_end,
and _IO_read_base are equal to each other. These are usually equal
to _IO_buf_base, though not necessarily if we have switched from
get mode to put mode. (The reason is to maintain the invariant
that _IO_read_end corresponds to the external file position.)
_IO_write_base is non-NULL and usually equal to _IO_buf_base.
We also have _IO_write_end == _IO_buf_end, but only in fully buffered mode.
The un-flushed character are those between _IO_write_base and _IO_write_ptr.
GET MODE:
If a filebuf is in get or putback mode, eback() != egptr().
In get mode, the unread characters are between gptr() and egptr().
The OS file position corresponds to that of egptr().
PUTBACK MODE:
Putback mode is used to remember "excess" characters that have
been sputbackc'd in a separate putback buffer.
In putback mode, the get buffer points to the special putback buffer.
The unread characters are the characters between gptr() and egptr()
in the putback buffer, as well as the area between save_gptr()
and save_egptr(), which point into the original reserve buffer.
(The pointers save_gptr() and save_egptr() are the values
of gptr() and egptr() at the time putback mode was entered.)
The OS position corresponds to that of save_egptr().
LINE BUFFERED OUTPUT:
During line buffered output, _IO_write_base==base() && epptr()==base().
However, ptr() may be anywhere between base() and ebuf().
This forces a call to filebuf::overflow(int C) on every put.
If there is more space in the buffer, and C is not a '\n',
then C is inserted, and pptr() incremented.
UNBUFFERED STREAMS:
If a filebuf is unbuffered(), the _shortbuf[1] is used as the buffer.
*/
#define CLOSED_FILEBUF_FLAGS \
(_IO_IS_FILEBUF+_IO_NO_READS+_IO_NO_WRITES+_IO_TIED_PUT_GET)
void
attribute_compat_text_section
_IO_old_file_init_internal (struct _IO_FILE_plus *fp)
{
/* POSIX.1 allows another file handle to be used to change the position
of our file descriptor. Hence we actually don't know the actual
position before we do the first fseek (and until a following fflush). */
fp->file._old_offset = _IO_pos_BAD;
fp->file._flags |= CLOSED_FILEBUF_FLAGS;
_IO_link_in (fp);
fp->file._vtable_offset = ((int) sizeof (struct _IO_FILE)
- (int) sizeof (struct _IO_FILE_complete));
fp->file._fileno = -1;
if (__builtin_expect (&_IO_stdin_used != NULL, 1)
|| (fp != (struct _IO_FILE_plus *) _IO_stdin
&& fp != (struct _IO_FILE_plus *) _IO_stdout
&& fp != (struct _IO_FILE_plus *) _IO_stderr))
/* The object is dynamically allocated and large enough. Initialize
the _mode element as well. */
((struct _IO_FILE_complete *) fp)->_mode = -1;
}
void
attribute_compat_text_section
_IO_old_file_init (struct _IO_FILE_plus *fp)
{
IO_set_accept_foreign_vtables (&_IO_vtable_check);
_IO_old_file_init_internal (fp);
}
int
attribute_compat_text_section
_IO_old_file_close_it (FILE *fp)
{
int write_status, close_status;
if (!_IO_file_is_open (fp))
return EOF;
write_status = _IO_old_do_flush (fp);
_IO_unsave_markers (fp);
close_status = ((fp->_flags2 & _IO_FLAGS2_NOCLOSE) == 0
? _IO_SYSCLOSE (fp) : 0);
/* Free buffer. */
_IO_setb (fp, NULL, NULL, 0);
_IO_setg (fp, NULL, NULL, NULL);
_IO_setp (fp, NULL, NULL);
_IO_un_link ((struct _IO_FILE_plus *) fp);
fp->_flags = _IO_MAGIC|CLOSED_FILEBUF_FLAGS;
fp->_fileno = -1;
fp->_old_offset = _IO_pos_BAD;
return close_status ? close_status : write_status;
}
void
attribute_compat_text_section
_IO_old_file_finish (FILE *fp, int dummy)
{
if (_IO_file_is_open (fp))
{
_IO_old_do_flush (fp);
if (!(fp->_flags & _IO_DELETE_DONT_CLOSE))
_IO_SYSCLOSE (fp);
}
_IO_default_finish (fp, 0);
}
FILE *
attribute_compat_text_section
_IO_old_file_fopen (FILE *fp, const char *filename, const char *mode)
{
int oflags = 0, omode;
int read_write, fdesc;
int oprot = 0666;
if (_IO_file_is_open (fp))
return 0;
switch (*mode++)
{
case 'r':
omode = O_RDONLY;
read_write = _IO_NO_WRITES;
break;
case 'w':
omode = O_WRONLY;
oflags = O_CREAT|O_TRUNC;
read_write = _IO_NO_READS;
break;
case 'a':
omode = O_WRONLY;
oflags = O_CREAT|O_APPEND;
read_write = _IO_NO_READS|_IO_IS_APPENDING;
break;
default:
__set_errno (EINVAL);
return NULL;
}
if (mode[0] == '+' || (mode[0] == 'b' && mode[1] == '+'))
{
omode = O_RDWR;
read_write &= _IO_IS_APPENDING;
}
fdesc = __open (filename, omode|oflags, oprot);
if (fdesc < 0)
return NULL;
fp->_fileno = fdesc;
_IO_mask_flags (fp, read_write,_IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);
if (read_write & _IO_IS_APPENDING)
if (_IO_SEEKOFF (fp, (off_t)0, _IO_seek_end, _IOS_INPUT|_IOS_OUTPUT)
== _IO_pos_BAD && errno != ESPIPE)
return NULL;
_IO_link_in ((struct _IO_FILE_plus *) fp);
return fp;
}
FILE *
attribute_compat_text_section
_IO_old_file_attach (FILE *fp, int fd)
{
if (_IO_file_is_open (fp))
return NULL;
fp->_fileno = fd;
fp->_flags &= ~(_IO_NO_READS+_IO_NO_WRITES);
fp->_flags |= _IO_DELETE_DONT_CLOSE;
/* Get the current position of the file. */
/* We have to do that since that may be junk. */
fp->_old_offset = _IO_pos_BAD;
if (_IO_SEEKOFF (fp, (off_t)0, _IO_seek_cur, _IOS_INPUT|_IOS_OUTPUT)
== _IO_pos_BAD && errno != ESPIPE)
return NULL;
return fp;
}
FILE *
attribute_compat_text_section
_IO_old_file_setbuf (FILE *fp, char *p, ssize_t len)
{
if (_IO_default_setbuf (fp, p, len) == NULL)
return NULL;
fp->_IO_write_base = fp->_IO_write_ptr = fp->_IO_write_end
= fp->_IO_buf_base;
_IO_setg (fp, fp->_IO_buf_base, fp->_IO_buf_base, fp->_IO_buf_base);
return fp;
}
static int old_do_write (FILE *, const char *, size_t);
/* Write TO_DO bytes from DATA to FP.
Then mark FP as having empty buffers. */
int
attribute_compat_text_section
_IO_old_do_write (FILE *fp, const char *data, size_t to_do)
{
return (to_do == 0 || (size_t) old_do_write (fp, data, to_do) == to_do)
? 0 : EOF;
}
static int
attribute_compat_text_section
old_do_write (FILE *fp, const char *data, size_t to_do)
{
size_t count;
if (fp->_flags & _IO_IS_APPENDING)
/* On a system without a proper O_APPEND implementation,
you would need to sys_seek(0, SEEK_END) here, but is
not needed nor desirable for Unix- or Posix-like systems.
Instead, just indicate that offset (before and after) is
unpredictable. */
fp->_old_offset = _IO_pos_BAD;
else if (fp->_IO_read_end != fp->_IO_write_base)
{
off_t new_pos
= _IO_SYSSEEK (fp, fp->_IO_write_base - fp->_IO_read_end, 1);
if (new_pos == _IO_pos_BAD)
return 0;
fp->_old_offset = new_pos;
}
count = _IO_SYSWRITE (fp, data, to_do);
if (fp->_cur_column && count)
fp->_cur_column = _IO_adjust_column (fp->_cur_column - 1, data, count) + 1;
_IO_setg (fp, fp->_IO_buf_base, fp->_IO_buf_base, fp->_IO_buf_base);
fp->_IO_write_base = fp->_IO_write_ptr = fp->_IO_buf_base;
fp->_IO_write_end = ((fp->_flags & (_IO_LINE_BUF | _IO_UNBUFFERED))
? fp->_IO_buf_base : fp->_IO_buf_end);
return count;
}
int
attribute_compat_text_section
_IO_old_file_underflow (FILE *fp)
{
ssize_t count;
/* C99 requires EOF to be "sticky". */
if (fp->_flags & _IO_EOF_SEEN)
return EOF;
if (fp->_flags & _IO_NO_READS)
{
fp->_flags |= _IO_ERR_SEEN;
__set_errno (EBADF);
return EOF;
}
if (fp->_IO_read_ptr < fp->_IO_read_end)
return *(unsigned char *) fp->_IO_read_ptr;
if (fp->_IO_buf_base == NULL)
{
/* Maybe we already have a push back pointer. */
if (fp->_IO_save_base != NULL)
{
free (fp->_IO_save_base);
fp->_flags &= ~_IO_IN_BACKUP;
}
_IO_doallocbuf (fp);
}
/* Flush all line buffered files before reading. */
/* FIXME This can/should be moved to genops ?? */
if (fp->_flags & (_IO_LINE_BUF|_IO_UNBUFFERED))
_IO_flush_all_linebuffered ();
_IO_switch_to_get_mode (fp);
/* This is very tricky. We have to adjust those
pointers before we call _IO_SYSREAD () since
we may longjump () out while waiting for
input. Those pointers may be screwed up. H.J. */
fp->_IO_read_base = fp->_IO_read_ptr = fp->_IO_buf_base;
fp->_IO_read_end = fp->_IO_buf_base;
fp->_IO_write_base = fp->_IO_write_ptr = fp->_IO_write_end
= fp->_IO_buf_base;
count = _IO_SYSREAD (fp, fp->_IO_buf_base,
fp->_IO_buf_end - fp->_IO_buf_base);
if (count <= 0)
{
if (count == 0)
fp->_flags |= _IO_EOF_SEEN;
else
fp->_flags |= _IO_ERR_SEEN, count = 0;
}
fp->_IO_read_end += count;
if (count == 0)
return EOF;
if (fp->_old_offset != _IO_pos_BAD)
_IO_pos_adjust (fp->_old_offset, count);
return *(unsigned char *) fp->_IO_read_ptr;
}
int
attribute_compat_text_section
_IO_old_file_overflow (FILE *f, int ch)
{
if (f->_flags & _IO_NO_WRITES) /* SET ERROR */
{
f->_flags |= _IO_ERR_SEEN;
__set_errno (EBADF);
return EOF;
}
/* If currently reading or no buffer allocated. */
if ((f->_flags & _IO_CURRENTLY_PUTTING) == 0)
{
/* Allocate a buffer if needed. */
if (f->_IO_write_base == 0)
{
_IO_doallocbuf (f);
_IO_setg (f, f->_IO_buf_base, f->_IO_buf_base, f->_IO_buf_base);
}
/* Otherwise must be currently reading.
If _IO_read_ptr (and hence also _IO_read_end) is at the buffer end,
logically slide the buffer forwards one block (by setting the
read pointers to all point at the beginning of the block). This
makes room for subsequent output.
Otherwise, set the read pointers to _IO_read_end (leaving that
alone, so it can continue to correspond to the external position). */
if (f->_IO_read_ptr == f->_IO_buf_end)
f->_IO_read_end = f->_IO_read_ptr = f->_IO_buf_base;
f->_IO_write_ptr = f->_IO_read_ptr;
f->_IO_write_base = f->_IO_write_ptr;
f->_IO_write_end = f->_IO_buf_end;
f->_IO_read_base = f->_IO_read_ptr = f->_IO_read_end;
if (f->_flags & (_IO_LINE_BUF | _IO_UNBUFFERED))
f->_IO_write_end = f->_IO_write_ptr;
f->_flags |= _IO_CURRENTLY_PUTTING;
}
if (ch == EOF)
return _IO_old_do_flush (f);
if (f->_IO_write_ptr == f->_IO_buf_end ) /* Buffer is really full */
if (_IO_old_do_flush (f) == EOF)
return EOF;
*f->_IO_write_ptr++ = ch;
if ((f->_flags & _IO_UNBUFFERED)
|| ((f->_flags & _IO_LINE_BUF) && ch == '\n'))
if (_IO_old_do_flush (f) == EOF)
return EOF;
return (unsigned char) ch;
}
int
attribute_compat_text_section
_IO_old_file_sync (FILE *fp)
{
ssize_t delta;
int retval = 0;
/* char* ptr = cur_ptr(); */
if (fp->_IO_write_ptr > fp->_IO_write_base)
if (_IO_old_do_flush(fp)) return EOF;
delta = fp->_IO_read_ptr - fp->_IO_read_end;
if (delta != 0)
{
#ifdef TODO
if (_IO_in_backup (fp))
delta -= eGptr () - Gbase ();
#endif
off_t new_pos = _IO_SYSSEEK (fp, delta, 1);
if (new_pos != (off_t) EOF)
fp->_IO_read_end = fp->_IO_read_ptr;
else if (errno == ESPIPE)
; /* Ignore error from unseekable devices. */
else
retval = EOF;
}
if (retval != EOF)
fp->_old_offset = _IO_pos_BAD;
/* FIXME: Cleanup - can this be shared? */
/* setg(base(), ptr, ptr); */
return retval;
}
off64_t
attribute_compat_text_section
_IO_old_file_seekoff (FILE *fp, off64_t offset, int dir, int mode)
{
off_t result;
off64_t delta, new_offset;
long count;
/* POSIX.1 8.2.3.7 says that after a call the fflush() the file
offset of the underlying file must be exact. */
int must_be_exact = (fp->_IO_read_base == fp->_IO_read_end
&& fp->_IO_write_base == fp->_IO_write_ptr);
if (mode == 0)
dir = _IO_seek_cur, offset = 0; /* Don't move any pointers. */
/* Flush unwritten characters.
(This may do an unneeded write if we seek within the buffer.
But to be able to switch to reading, we would need to set
egptr to pptr. That can't be done in the current design,
which assumes file_ptr() is eGptr. Anyway, since we probably
end up flushing when we close(), it doesn't make much difference.)
FIXME: simulate mem-mapped files. */
if (fp->_IO_write_ptr > fp->_IO_write_base || _IO_in_put_mode (fp))
if (_IO_switch_to_get_mode (fp))
return EOF;
if (fp->_IO_buf_base == NULL)
{
/* It could be that we already have a pushback buffer. */
if (fp->_IO_read_base != NULL)
{
free (fp->_IO_read_base);
fp->_flags &= ~_IO_IN_BACKUP;
}
_IO_doallocbuf (fp);
_IO_setp (fp, fp->_IO_buf_base, fp->_IO_buf_base);
_IO_setg (fp, fp->_IO_buf_base, fp->_IO_buf_base, fp->_IO_buf_base);
}
switch (dir)
{
case _IO_seek_cur:
/* Adjust for read-ahead (bytes is buffer). */
offset -= fp->_IO_read_end - fp->_IO_read_ptr;
if (fp->_old_offset == _IO_pos_BAD)
goto dumb;
/* Make offset absolute, assuming current pointer is file_ptr(). */
offset += fp->_old_offset;
dir = _IO_seek_set;
break;
case _IO_seek_set:
break;
case _IO_seek_end:
{
struct stat64 st;
if (_IO_SYSSTAT (fp, &st) == 0 && S_ISREG (st.st_mode))
{
offset += st.st_size;
dir = _IO_seek_set;
}
else
goto dumb;
}
}
/* At this point, dir==_IO_seek_set. */
/* If we are only interested in the current position we've found it now. */
if (mode == 0)
return offset;
/* If destination is within current buffer, optimize: */
if (fp->_old_offset != _IO_pos_BAD && fp->_IO_read_base != NULL
&& !_IO_in_backup (fp))
{
/* Offset relative to start of main get area. */
off_t rel_offset = (offset - fp->_old_offset
+ (fp->_IO_read_end - fp->_IO_read_base));
if (rel_offset >= 0)
{
if (rel_offset <= fp->_IO_read_end - fp->_IO_read_base)
{
_IO_setg (fp, fp->_IO_buf_base, fp->_IO_buf_base + rel_offset,
fp->_IO_read_end);
_IO_setp (fp, fp->_IO_buf_base, fp->_IO_buf_base);
{
_IO_mask_flags (fp, 0, _IO_EOF_SEEN);
goto resync;
}
}
#ifdef TODO
/* If we have streammarkers, seek forward by reading ahead. */
if (_IO_have_markers (fp))
{
int to_skip = rel_offset
- (fp->_IO_read_ptr - fp->_IO_read_base);
if (ignore (to_skip) != to_skip)
goto dumb;
_IO_mask_flags (fp, 0, _IO_EOF_SEEN);
goto resync;
}
#endif
}
#ifdef TODO
if (rel_offset < 0 && rel_offset >= Bbase () - Bptr ())
{
if (!_IO_in_backup (fp))
_IO_switch_to_backup_area (fp);
gbump (fp->_IO_read_end + rel_offset - fp->_IO_read_ptr);
_IO_mask_flags (fp, 0, _IO_EOF_SEEN);
goto resync;
}
#endif
}
#ifdef TODO
_IO_unsave_markers (fp);
#endif
if (fp->_flags & _IO_NO_READS)
goto dumb;
/* Try to seek to a block boundary, to improve kernel page management. */
new_offset = offset & ~(fp->_IO_buf_end - fp->_IO_buf_base - 1);
delta = offset - new_offset;
if (delta > fp->_IO_buf_end - fp->_IO_buf_base)
{
new_offset = offset;
delta = 0;
}
result = _IO_SYSSEEK (fp, new_offset, 0);
if (result < 0)
return EOF;
if (delta == 0)
count = 0;
else
{
count = _IO_SYSREAD (fp, fp->_IO_buf_base,
(must_be_exact
? delta : fp->_IO_buf_end - fp->_IO_buf_base));
if (count < delta)
{
/* We weren't allowed to read, but try to seek the remainder. */
offset = count == EOF ? delta : delta-count;
dir = _IO_seek_cur;
goto dumb;
}
}
_IO_setg (fp, fp->_IO_buf_base, fp->_IO_buf_base + delta,
fp->_IO_buf_base + count);
_IO_setp (fp, fp->_IO_buf_base, fp->_IO_buf_base);
fp->_old_offset = result + count;
_IO_mask_flags (fp, 0, _IO_EOF_SEEN);
return offset;
dumb:
_IO_unsave_markers (fp);
result = _IO_SYSSEEK (fp, offset, dir);
if (result != EOF)
{
_IO_mask_flags (fp, 0, _IO_EOF_SEEN);
fp->_old_offset = result;
_IO_setg (fp, fp->_IO_buf_base, fp->_IO_buf_base, fp->_IO_buf_base);
_IO_setp (fp, fp->_IO_buf_base, fp->_IO_buf_base);
}
return result;
resync:
/* We need to do it since it is possible that the file offset in
the kernel may be changed behind our back. It may happen when
we fopen a file and then do a fork. One process may access the
file and the kernel file offset will be changed. */
if (fp->_old_offset >= 0)
_IO_SYSSEEK (fp, fp->_old_offset, 0);
return offset;
}
ssize_t
attribute_compat_text_section
_IO_old_file_write (FILE *f, const void *data, ssize_t n)
{
ssize_t to_do = n;
while (to_do > 0)
{
ssize_t count = __write (f->_fileno, data, to_do);
if (count == EOF)
{
f->_flags |= _IO_ERR_SEEN;
break;
}
to_do -= count;
data = (void *) ((char *) data + count);
}
n -= to_do;
if (f->_old_offset >= 0)
f->_old_offset += n;
return n;
}
size_t
attribute_compat_text_section
_IO_old_file_xsputn (FILE *f, const void *data, size_t n)
{
const char *s = (char *) data;
size_t to_do = n;
int must_flush = 0;
size_t count = 0;
if (n <= 0)
return 0;
/* This is an optimized implementation.
If the amount to be written straddles a block boundary
(or the filebuf is unbuffered), use sys_write directly. */
/* First figure out how much space is available in the buffer. */
if ((f->_flags & _IO_LINE_BUF) && (f->_flags & _IO_CURRENTLY_PUTTING))
{
count = f->_IO_buf_end - f->_IO_write_ptr;
if (count >= n)
{
const char *p;
for (p = s + n; p > s; )
{
if (*--p == '\n')
{
count = p - s + 1;
must_flush = 1;
break;
}
}
}
}
else if (f->_IO_write_end > f->_IO_write_ptr)
count = f->_IO_write_end - f->_IO_write_ptr; /* Space available. */
/* Then fill the buffer. */
if (count > 0)
{
if (count > to_do)
count = to_do;
if (count > 20)
{
f->_IO_write_ptr = __mempcpy (f->_IO_write_ptr, s, count);
s += count;
}
else
{
char *p = f->_IO_write_ptr;
int i = (int) count;
while (--i >= 0)
*p++ = *s++;
f->_IO_write_ptr = p;
}
to_do -= count;
}
if (to_do + must_flush > 0)
{
size_t block_size, do_write;
/* Next flush the (full) buffer. */
if (__overflow (f, EOF) == EOF)
return to_do == 0 ? EOF : n - to_do;
/* Try to maintain alignment: write a whole number of blocks.
dont_write is what gets left over. */
block_size = f->_IO_buf_end - f->_IO_buf_base;
do_write = to_do - (block_size >= 128 ? to_do % block_size : 0);
if (do_write)
{
count = old_do_write (f, s, do_write);
to_do -= count;
if (count < do_write)
return n - to_do;
}
/* Now write out the remainder. Normally, this will fit in the
buffer, but it's somewhat messier for line-buffered files,
so we let _IO_default_xsputn handle the general case. */
if (to_do)
to_do -= _IO_default_xsputn (f, s+do_write, to_do);
}
return n - to_do;
}
const struct _IO_jump_t _IO_old_file_jumps libio_vtable =
{
JUMP_INIT_DUMMY,
JUMP_INIT(finish, _IO_old_file_finish),
JUMP_INIT(overflow, _IO_old_file_overflow),
JUMP_INIT(underflow, _IO_old_file_underflow),
JUMP_INIT(uflow, _IO_default_uflow),
JUMP_INIT(pbackfail, _IO_default_pbackfail),
JUMP_INIT(xsputn, _IO_old_file_xsputn),
JUMP_INIT(xsgetn, _IO_default_xsgetn),
JUMP_INIT(seekoff, _IO_old_file_seekoff),
JUMP_INIT(seekpos, _IO_default_seekpos),
JUMP_INIT(setbuf, _IO_old_file_setbuf),
JUMP_INIT(sync, _IO_old_file_sync),
JUMP_INIT(doallocate, _IO_file_doallocate),
JUMP_INIT(read, _IO_file_read),
JUMP_INIT(write, _IO_old_file_write),
JUMP_INIT(seek, _IO_file_seek),
JUMP_INIT(close, _IO_file_close),
JUMP_INIT(stat, _IO_file_stat)
};
compat_symbol (libc, _IO_old_do_write, _IO_do_write, GLIBC_2_0);
compat_symbol (libc, _IO_old_file_attach, _IO_file_attach, GLIBC_2_0);
compat_symbol (libc, _IO_old_file_close_it, _IO_file_close_it, GLIBC_2_0);
compat_symbol (libc, _IO_old_file_finish, _IO_file_finish, GLIBC_2_0);
compat_symbol (libc, _IO_old_file_fopen, _IO_file_fopen, GLIBC_2_0);
compat_symbol (libc, _IO_old_file_init, _IO_file_init, GLIBC_2_0);
compat_symbol (libc, _IO_old_file_setbuf, _IO_file_setbuf, GLIBC_2_0);
compat_symbol (libc, _IO_old_file_sync, _IO_file_sync, GLIBC_2_0);
compat_symbol (libc, _IO_old_file_overflow, _IO_file_overflow, GLIBC_2_0);
compat_symbol (libc, _IO_old_file_seekoff, _IO_file_seekoff, GLIBC_2_0);
compat_symbol (libc, _IO_old_file_underflow, _IO_file_underflow, GLIBC_2_0);
compat_symbol (libc, _IO_old_file_write, _IO_file_write, GLIBC_2_0);
compat_symbol (libc, _IO_old_file_xsputn, _IO_file_xsputn, GLIBC_2_0);
#endif