glibc/libio/wfileops.c
Florian Weimer ecc7c3deb9 libio: Check remaining buffer size in _IO_wdo_write (bug 31183)
The multibyte character needs to fit into the remaining buffer space,
not the already-written buffer space.  Without the fix, we were never
moving the write pointer from the start of the buffer, always using
the single-character fallback buffer.

Fixes commit 04b76b5aa8 ("Don't error out writing
a multibyte character to an unbuffered stream (bug 17522)").
2024-01-02 14:36:17 +01:00

1020 lines
30 KiB
C

/* Copyright (C) 1993-2024 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 <assert.h>
#include <libioP.h>
#include <wchar.h>
#include <gconv.h>
#include <stdlib.h>
#include <string.h>
/* Convert TO_DO wide character from DATA to FP.
Then mark FP as having empty buffers. */
int
_IO_wdo_write (FILE *fp, const wchar_t *data, size_t to_do)
{
struct _IO_codecvt *cc = fp->_codecvt;
if (to_do > 0)
{
if (fp->_IO_write_end == fp->_IO_write_ptr
&& fp->_IO_write_end != fp->_IO_write_base)
{
if (_IO_new_do_write (fp, fp->_IO_write_base,
fp->_IO_write_ptr - fp->_IO_write_base) == EOF)
return WEOF;
}
do
{
enum __codecvt_result result;
const wchar_t *new_data;
char mb_buf[MB_LEN_MAX];
char *write_base, *write_ptr, *buf_end;
if (fp->_IO_buf_end - fp->_IO_write_ptr < sizeof (mb_buf))
{
/* Make sure we have room for at least one multibyte
character. */
write_ptr = write_base = mb_buf;
buf_end = mb_buf + sizeof (mb_buf);
}
else
{
write_ptr = fp->_IO_write_ptr;
write_base = fp->_IO_write_base;
buf_end = fp->_IO_buf_end;
}
/* Now convert from the internal format into the external buffer. */
result = __libio_codecvt_out (cc, &fp->_wide_data->_IO_state,
data, data + to_do, &new_data,
write_ptr,
buf_end,
&write_ptr);
/* Write out what we produced so far. */
if (_IO_new_do_write (fp, write_base, write_ptr - write_base) == EOF)
/* Something went wrong. */
return WEOF;
to_do -= new_data - data;
/* Next see whether we had problems during the conversion. If yes,
we cannot go on. */
if (result != __codecvt_ok
&& (result != __codecvt_partial || new_data - data == 0))
break;
data = new_data;
}
while (to_do > 0);
}
_IO_wsetg (fp, fp->_wide_data->_IO_buf_base, fp->_wide_data->_IO_buf_base,
fp->_wide_data->_IO_buf_base);
fp->_wide_data->_IO_write_base = fp->_wide_data->_IO_write_ptr
= fp->_wide_data->_IO_buf_base;
fp->_wide_data->_IO_write_end = ((fp->_flags & (_IO_LINE_BUF | _IO_UNBUFFERED))
? fp->_wide_data->_IO_buf_base
: fp->_wide_data->_IO_buf_end);
return to_do == 0 ? 0 : WEOF;
}
libc_hidden_def (_IO_wdo_write)
wint_t
_IO_wfile_underflow (FILE *fp)
{
struct _IO_codecvt *cd;
enum __codecvt_result status;
ssize_t count;
/* C99 requires EOF to be "sticky". */
if (fp->_flags & _IO_EOF_SEEN)
return WEOF;
if (__glibc_unlikely (fp->_flags & _IO_NO_READS))
{
fp->_flags |= _IO_ERR_SEEN;
__set_errno (EBADF);
return WEOF;
}
if (fp->_wide_data->_IO_read_ptr < fp->_wide_data->_IO_read_end)
return *fp->_wide_data->_IO_read_ptr;
cd = fp->_codecvt;
/* Maybe there is something left in the external buffer. */
if (fp->_IO_read_ptr < fp->_IO_read_end)
{
/* There is more in the external. Convert it. */
const char *read_stop = (const char *) fp->_IO_read_ptr;
fp->_wide_data->_IO_last_state = fp->_wide_data->_IO_state;
fp->_wide_data->_IO_read_base = fp->_wide_data->_IO_read_ptr =
fp->_wide_data->_IO_buf_base;
status = __libio_codecvt_in (cd, &fp->_wide_data->_IO_state,
fp->_IO_read_ptr, fp->_IO_read_end,
&read_stop,
fp->_wide_data->_IO_read_ptr,
fp->_wide_data->_IO_buf_end,
&fp->_wide_data->_IO_read_end);
fp->_IO_read_base = fp->_IO_read_ptr;
fp->_IO_read_ptr = (char *) read_stop;
/* If we managed to generate some text return the next character. */
if (fp->_wide_data->_IO_read_ptr < fp->_wide_data->_IO_read_end)
return *fp->_wide_data->_IO_read_ptr;
if (status == __codecvt_error)
{
__set_errno (EILSEQ);
fp->_flags |= _IO_ERR_SEEN;
return WEOF;
}
/* Move the remaining content of the read buffer to the beginning. */
memmove (fp->_IO_buf_base, fp->_IO_read_ptr,
fp->_IO_read_end - fp->_IO_read_ptr);
fp->_IO_read_end = (fp->_IO_buf_base
+ (fp->_IO_read_end - fp->_IO_read_ptr));
fp->_IO_read_base = fp->_IO_read_ptr = fp->_IO_buf_base;
}
else
fp->_IO_read_base = fp->_IO_read_ptr = fp->_IO_read_end =
fp->_IO_buf_base;
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);
fp->_IO_read_base = fp->_IO_read_ptr = fp->_IO_read_end =
fp->_IO_buf_base;
}
fp->_IO_write_base = fp->_IO_write_ptr = fp->_IO_write_end =
fp->_IO_buf_base;
if (fp->_wide_data->_IO_buf_base == NULL)
{
/* Maybe we already have a push back pointer. */
if (fp->_wide_data->_IO_save_base != NULL)
{
free (fp->_wide_data->_IO_save_base);
fp->_flags &= ~_IO_IN_BACKUP;
}
_IO_wdoallocbuf (fp);
}
/* FIXME This can/should be moved to genops ?? */
if (fp->_flags & (_IO_LINE_BUF | _IO_UNBUFFERED))
{
/* We used to flush all line-buffered stream. This really isn't
required by any standard. My recollection is that
traditional Unix systems did this for stdout. stderr better
not be line buffered. So we do just that here
explicitly. --drepper */
_IO_acquire_lock (stdout);
if ((stdout->_flags & (_IO_LINKED | _IO_NO_WRITES | _IO_LINE_BUF))
== (_IO_LINKED | _IO_LINE_BUF))
_IO_OVERFLOW (stdout, EOF);
_IO_release_lock (stdout);
}
_IO_switch_to_get_mode (fp);
fp->_wide_data->_IO_read_base = fp->_wide_data->_IO_read_ptr =
fp->_wide_data->_IO_buf_base;
fp->_wide_data->_IO_read_end = fp->_wide_data->_IO_buf_base;
fp->_wide_data->_IO_write_base = fp->_wide_data->_IO_write_ptr =
fp->_wide_data->_IO_write_end = fp->_wide_data->_IO_buf_base;
const char *read_ptr_copy;
char accbuf[MB_LEN_MAX];
size_t naccbuf = 0;
again:
count = _IO_SYSREAD (fp, fp->_IO_read_end,
fp->_IO_buf_end - fp->_IO_read_end);
if (count <= 0)
{
if (count == 0 && naccbuf == 0)
{
fp->_flags |= _IO_EOF_SEEN;
fp->_offset = _IO_pos_BAD;
}
else
fp->_flags |= _IO_ERR_SEEN, count = 0;
}
fp->_IO_read_end += count;
if (count == 0)
{
if (naccbuf != 0)
/* There are some bytes in the external buffer but they don't
convert to anything. */
__set_errno (EILSEQ);
return WEOF;
}
if (fp->_offset != _IO_pos_BAD)
_IO_pos_adjust (fp->_offset, count);
/* Now convert the read input. */
fp->_wide_data->_IO_last_state = fp->_wide_data->_IO_state;
fp->_IO_read_base = fp->_IO_read_ptr;
const char *from = fp->_IO_read_ptr;
const char *to = fp->_IO_read_end;
size_t to_copy = count;
if (__glibc_unlikely (naccbuf != 0))
{
to_copy = MIN (sizeof (accbuf) - naccbuf, count);
to = __mempcpy (&accbuf[naccbuf], from, to_copy);
naccbuf += to_copy;
from = accbuf;
}
status = __libio_codecvt_in (cd, &fp->_wide_data->_IO_state,
from, to, &read_ptr_copy,
fp->_wide_data->_IO_read_end,
fp->_wide_data->_IO_buf_end,
&fp->_wide_data->_IO_read_end);
if (__glibc_unlikely (naccbuf != 0))
fp->_IO_read_ptr += MAX (0, read_ptr_copy - &accbuf[naccbuf - to_copy]);
else
fp->_IO_read_ptr = (char *) read_ptr_copy;
if (fp->_wide_data->_IO_read_end == fp->_wide_data->_IO_buf_base)
{
if (status == __codecvt_error)
{
out_eilseq:
__set_errno (EILSEQ);
fp->_flags |= _IO_ERR_SEEN;
return WEOF;
}
/* The read bytes make no complete character. Try reading again. */
assert (status == __codecvt_partial);
if (naccbuf == 0)
{
if (fp->_IO_read_base < fp->_IO_read_ptr)
{
/* Partially used the buffer for some input data that
produces no output. */
size_t avail = fp->_IO_read_end - fp->_IO_read_ptr;
memmove (fp->_IO_read_base, fp->_IO_read_ptr, avail);
fp->_IO_read_ptr = fp->_IO_read_base;
fp->_IO_read_end -= avail;
goto again;
}
naccbuf = fp->_IO_read_end - fp->_IO_read_ptr;
if (naccbuf >= sizeof (accbuf))
goto out_eilseq;
memcpy (accbuf, fp->_IO_read_ptr, naccbuf);
}
else
{
size_t used = read_ptr_copy - accbuf;
if (used > 0)
{
memmove (accbuf, read_ptr_copy, naccbuf - used);
naccbuf -= used;
}
if (naccbuf == sizeof (accbuf))
goto out_eilseq;
}
fp->_IO_read_ptr = fp->_IO_read_end = fp->_IO_read_base;
goto again;
}
return *fp->_wide_data->_IO_read_ptr;
}
libc_hidden_def (_IO_wfile_underflow)
wint_t
_IO_wfile_underflow_mmap (FILE *fp)
{
struct _IO_codecvt *cd;
const char *read_stop;
if (__glibc_unlikely (fp->_flags & _IO_NO_READS))
{
fp->_flags |= _IO_ERR_SEEN;
__set_errno (EBADF);
return WEOF;
}
if (fp->_wide_data->_IO_read_ptr < fp->_wide_data->_IO_read_end)
return *fp->_wide_data->_IO_read_ptr;
cd = fp->_codecvt;
/* Maybe there is something left in the external buffer. */
if (fp->_IO_read_ptr >= fp->_IO_read_end
/* No. But maybe the read buffer is not fully set up. */
&& _IO_file_underflow_mmap (fp) == EOF)
/* Nothing available. _IO_file_underflow_mmap has set the EOF or error
flags as appropriate. */
return WEOF;
/* There is more in the external. Convert it. */
read_stop = (const char *) fp->_IO_read_ptr;
if (fp->_wide_data->_IO_buf_base == NULL)
{
/* Maybe we already have a push back pointer. */
if (fp->_wide_data->_IO_save_base != NULL)
{
free (fp->_wide_data->_IO_save_base);
fp->_flags &= ~_IO_IN_BACKUP;
}
_IO_wdoallocbuf (fp);
}
fp->_wide_data->_IO_last_state = fp->_wide_data->_IO_state;
fp->_wide_data->_IO_read_base = fp->_wide_data->_IO_read_ptr =
fp->_wide_data->_IO_buf_base;
__libio_codecvt_in (cd, &fp->_wide_data->_IO_state,
fp->_IO_read_ptr, fp->_IO_read_end,
&read_stop,
fp->_wide_data->_IO_read_ptr,
fp->_wide_data->_IO_buf_end,
&fp->_wide_data->_IO_read_end);
fp->_IO_read_ptr = (char *) read_stop;
/* If we managed to generate some text return the next character. */
if (fp->_wide_data->_IO_read_ptr < fp->_wide_data->_IO_read_end)
return *fp->_wide_data->_IO_read_ptr;
/* There is some garbage at the end of the file. */
__set_errno (EILSEQ);
fp->_flags |= _IO_ERR_SEEN;
return WEOF;
}
wint_t
_IO_wfile_underflow_maybe_mmap (FILE *fp)
{
/* This is the first read attempt. Doing the underflow will choose mmap
or vanilla operations and then punt to the chosen underflow routine.
Then we can punt to ours. */
if (_IO_file_underflow_maybe_mmap (fp) == EOF)
return WEOF;
return _IO_WUNDERFLOW (fp);
}
wint_t
_IO_wfile_overflow (FILE *f, wint_t wch)
{
if (f->_flags & _IO_NO_WRITES) /* SET ERROR */
{
f->_flags |= _IO_ERR_SEEN;
__set_errno (EBADF);
return WEOF;
}
/* If currently reading or no buffer allocated. */
if ((f->_flags & _IO_CURRENTLY_PUTTING) == 0
|| f->_wide_data->_IO_write_base == NULL)
{
/* Allocate a buffer if needed. */
if (f->_wide_data->_IO_write_base == 0)
{
_IO_wdoallocbuf (f);
_IO_free_wbackup_area (f);
_IO_wsetg (f, f->_wide_data->_IO_buf_base,
f->_wide_data->_IO_buf_base, f->_wide_data->_IO_buf_base);
if (f->_IO_write_base == NULL)
{
_IO_doallocbuf (f);
_IO_setg (f, f->_IO_buf_base, f->_IO_buf_base, f->_IO_buf_base);
}
}
else
{
/* 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->_wide_data->_IO_read_ptr == f->_wide_data->_IO_buf_end)
{
f->_IO_read_end = f->_IO_read_ptr = f->_IO_buf_base;
f->_wide_data->_IO_read_end = f->_wide_data->_IO_read_ptr =
f->_wide_data->_IO_buf_base;
}
}
f->_wide_data->_IO_write_ptr = f->_wide_data->_IO_read_ptr;
f->_wide_data->_IO_write_base = f->_wide_data->_IO_write_ptr;
f->_wide_data->_IO_write_end = f->_wide_data->_IO_buf_end;
f->_wide_data->_IO_read_base = f->_wide_data->_IO_read_ptr =
f->_wide_data->_IO_read_end;
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;
f->_flags |= _IO_CURRENTLY_PUTTING;
if (f->_flags & (_IO_LINE_BUF | _IO_UNBUFFERED))
f->_wide_data->_IO_write_end = f->_wide_data->_IO_write_ptr;
}
if (wch == WEOF)
return _IO_do_flush (f);
if (f->_wide_data->_IO_write_ptr == f->_wide_data->_IO_buf_end)
/* Buffer is really full */
if (_IO_do_flush (f) == EOF)
return WEOF;
*f->_wide_data->_IO_write_ptr++ = wch;
if ((f->_flags & _IO_UNBUFFERED)
|| ((f->_flags & _IO_LINE_BUF) && wch == L'\n'))
if (_IO_do_flush (f) == EOF)
return WEOF;
return wch;
}
libc_hidden_def (_IO_wfile_overflow)
wint_t
_IO_wfile_sync (FILE *fp)
{
ssize_t delta;
wint_t retval = 0;
/* char* ptr = cur_ptr(); */
if (fp->_wide_data->_IO_write_ptr > fp->_wide_data->_IO_write_base)
if (_IO_do_flush (fp))
return WEOF;
delta = fp->_wide_data->_IO_read_ptr - fp->_wide_data->_IO_read_end;
if (delta != 0)
{
/* We have to find out how many bytes we have to go back in the
external buffer. */
struct _IO_codecvt *cv = fp->_codecvt;
off64_t new_pos;
int clen = __libio_codecvt_encoding (cv);
if (clen > 0)
/* It is easy, a fixed number of input bytes are used for each
wide character. */
delta *= clen;
else
{
/* We have to find out the hard way how much to back off.
To do this we determine how much input we needed to
generate the wide characters up to the current reading
position. */
int nread;
size_t wnread = (fp->_wide_data->_IO_read_ptr
- fp->_wide_data->_IO_read_base);
fp->_wide_data->_IO_state = fp->_wide_data->_IO_last_state;
nread = __libio_codecvt_length (cv, &fp->_wide_data->_IO_state,
fp->_IO_read_base,
fp->_IO_read_end, wnread);
fp->_IO_read_ptr = fp->_IO_read_base + nread;
delta = -(fp->_IO_read_end - fp->_IO_read_base - nread);
}
new_pos = _IO_SYSSEEK (fp, delta, 1);
if (new_pos != (off64_t) EOF)
{
fp->_wide_data->_IO_read_end = fp->_wide_data->_IO_read_ptr;
fp->_IO_read_end = fp->_IO_read_ptr;
}
else if (errno == ESPIPE)
; /* Ignore error from unseekable devices. */
else
retval = WEOF;
}
if (retval != WEOF)
fp->_offset = _IO_pos_BAD;
/* FIXME: Cleanup - can this be shared? */
/* setg(base(), ptr, ptr); */
return retval;
}
libc_hidden_def (_IO_wfile_sync)
/* Adjust the internal buffer pointers to reflect the state in the external
buffer. The content between fp->_IO_read_base and fp->_IO_read_ptr is
assumed to be converted and available in the range
fp->_wide_data->_IO_read_base and fp->_wide_data->_IO_read_end.
Returns 0 on success and -1 on error with the _IO_ERR_SEEN flag set. */
static int
adjust_wide_data (FILE *fp, bool do_convert)
{
struct _IO_codecvt *cv = fp->_codecvt;
int clen = __libio_codecvt_encoding (cv);
/* Take the easy way out for constant length encodings if we don't need to
convert. */
if (!do_convert && clen > 0)
{
fp->_wide_data->_IO_read_end += ((fp->_IO_read_ptr - fp->_IO_read_base)
/ clen);
goto done;
}
enum __codecvt_result status;
const char *read_stop = (const char *) fp->_IO_read_base;
do
{
fp->_wide_data->_IO_last_state = fp->_wide_data->_IO_state;
status = __libio_codecvt_in (cv, &fp->_wide_data->_IO_state,
fp->_IO_read_base, fp->_IO_read_ptr,
&read_stop,
fp->_wide_data->_IO_read_base,
fp->_wide_data->_IO_buf_end,
&fp->_wide_data->_IO_read_end);
/* Should we return EILSEQ? */
if (__glibc_unlikely (status == __codecvt_error))
{
fp->_flags |= _IO_ERR_SEEN;
return -1;
}
}
while (__builtin_expect (status == __codecvt_partial, 0));
done:
/* Now seek to _IO_read_end to behave as if we have read it all in. */
fp->_wide_data->_IO_read_ptr = fp->_wide_data->_IO_read_end;
return 0;
}
/* ftell{,o} implementation for wide mode. Don't modify any state of the file
pointer while we try to get the current state of the stream except in one
case, which is when we have unflushed writes in append mode. */
static off64_t
do_ftell_wide (FILE *fp)
{
off64_t result, offset = 0;
/* No point looking for offsets in the buffer if it hasn't even been
allocated. */
if (fp->_wide_data->_IO_buf_base != NULL)
{
const wchar_t *wide_read_base;
const wchar_t *wide_read_ptr;
const wchar_t *wide_read_end;
bool unflushed_writes = (fp->_wide_data->_IO_write_ptr
> fp->_wide_data->_IO_write_base);
bool append_mode = (fp->_flags & _IO_IS_APPENDING) == _IO_IS_APPENDING;
/* When we have unflushed writes in append mode, seek to the end of the
file and record that offset. This is the only time we change the file
stream state and it is safe since the file handle is active. */
if (unflushed_writes && append_mode)
{
result = _IO_SYSSEEK (fp, 0, _IO_seek_end);
if (result == _IO_pos_BAD)
return EOF;
else
fp->_offset = result;
}
/* XXX For wide stream with backup store it is not very
reasonable to determine the offset. The pushed-back
character might require a state change and we need not be
able to compute the initial state by reverse transformation
since there is no guarantee of symmetry. So we don't even
try and return an error. */
if (_IO_in_backup (fp))
{
if (fp->_wide_data->_IO_read_ptr < fp->_wide_data->_IO_read_end)
{
__set_errno (EINVAL);
return -1;
}
/* Nothing in the backup store, so note the backed up pointers
without changing the state. */
wide_read_base = fp->_wide_data->_IO_save_base;
wide_read_ptr = wide_read_base;
wide_read_end = fp->_wide_data->_IO_save_end;
}
else
{
wide_read_base = fp->_wide_data->_IO_read_base;
wide_read_ptr = fp->_wide_data->_IO_read_ptr;
wide_read_end = fp->_wide_data->_IO_read_end;
}
struct _IO_codecvt *cv = fp->_codecvt;
int clen = __libio_codecvt_encoding (cv);
if (!unflushed_writes)
{
if (clen > 0)
{
offset -= (wide_read_end - wide_read_ptr) * clen;
offset -= fp->_IO_read_end - fp->_IO_read_ptr;
}
else
{
int nread;
size_t delta = wide_read_ptr - wide_read_base;
__mbstate_t state = fp->_wide_data->_IO_last_state;
nread = __libio_codecvt_length (cv, &state,
fp->_IO_read_base,
fp->_IO_read_end, delta);
offset -= fp->_IO_read_end - fp->_IO_read_base - nread;
}
}
else
{
if (clen > 0)
offset += (fp->_wide_data->_IO_write_ptr
- fp->_wide_data->_IO_write_base) * clen;
else
{
size_t delta = (fp->_wide_data->_IO_write_ptr
- fp->_wide_data->_IO_write_base);
/* Allocate enough space for the conversion. */
size_t outsize = delta * sizeof (wchar_t);
char *out = malloc (outsize);
char *outstop = out;
const wchar_t *in = fp->_wide_data->_IO_write_base;
enum __codecvt_result status;
__mbstate_t state = fp->_wide_data->_IO_last_state;
status = __libio_codecvt_out (cv, &state, in, in + delta, &in,
out, out + outsize, &outstop);
/* We don't check for __codecvt_partial because it can be
returned on one of two conditions: either the output
buffer is full or the input sequence is incomplete. We
take care to allocate enough buffer and our input
sequences must be complete since they are accepted as
wchar_t; if not, then that is an error. */
if (__glibc_unlikely (status != __codecvt_ok))
{
free (out);
return WEOF;
}
offset += outstop - out;
free (out);
}
/* We don't trust _IO_read_end to represent the current file offset
when writing in append mode because the value would have to be
shifted to the end of the file during a flush. Use the write base
instead, along with the new offset we got above when we did a seek
to the end of the file. */
if (append_mode)
offset += fp->_IO_write_ptr - fp->_IO_write_base;
/* For all other modes, _IO_read_end represents the file offset. */
else
offset += fp->_IO_write_ptr - fp->_IO_read_end;
}
}
if (fp->_offset != _IO_pos_BAD)
result = fp->_offset;
else
result = _IO_SYSSEEK (fp, 0, _IO_seek_cur);
if (result == EOF)
return result;
result += offset;
if (result < 0)
{
__set_errno (EINVAL);
return EOF;
}
return result;
}
off64_t
_IO_wfile_seekoff (FILE *fp, off64_t offset, int dir, int mode)
{
off64_t result;
off64_t delta, new_offset;
long int count;
/* Short-circuit into a separate function. We don't want to mix any
functionality and we don't want to touch anything inside the FILE
object. */
if (mode == 0)
return do_ftell_wide (fp);
/* 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->_wide_data->_IO_read_base
== fp->_wide_data->_IO_read_end)
&& (fp->_wide_data->_IO_write_base
== fp->_wide_data->_IO_write_ptr));
bool was_writing = ((fp->_wide_data->_IO_write_ptr
> fp->_wide_data->_IO_write_base)
|| _IO_in_put_mode (fp));
/* 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 (was_writing && _IO_switch_to_wget_mode (fp))
return WEOF;
if (fp->_wide_data->_IO_buf_base == NULL)
{
/* It could be that we already have a pushback buffer. */
if (fp->_wide_data->_IO_read_base != NULL)
{
free (fp->_wide_data->_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);
_IO_wsetp (fp, fp->_wide_data->_IO_buf_base,
fp->_wide_data->_IO_buf_base);
_IO_wsetg (fp, fp->_wide_data->_IO_buf_base,
fp->_wide_data->_IO_buf_base, fp->_wide_data->_IO_buf_base);
}
switch (dir)
{
struct _IO_codecvt *cv;
int clen;
case _IO_seek_cur:
/* Adjust for read-ahead (bytes is buffer). To do this we must
find out which position in the external buffer corresponds to
the current position in the internal buffer. */
cv = fp->_codecvt;
clen = __libio_codecvt_encoding (cv);
if (mode != 0 || !was_writing)
{
if (clen > 0)
{
offset -= (fp->_wide_data->_IO_read_end
- fp->_wide_data->_IO_read_ptr) * clen;
/* Adjust by readahead in external buffer. */
offset -= fp->_IO_read_end - fp->_IO_read_ptr;
}
else
{
int nread;
delta = (fp->_wide_data->_IO_read_ptr
- fp->_wide_data->_IO_read_base);
fp->_wide_data->_IO_state = fp->_wide_data->_IO_last_state;
nread = __libio_codecvt_length (cv,
&fp->_wide_data->_IO_state,
fp->_IO_read_base,
fp->_IO_read_end, delta);
fp->_IO_read_ptr = fp->_IO_read_base + nread;
fp->_wide_data->_IO_read_end = fp->_wide_data->_IO_read_ptr;
offset -= fp->_IO_read_end - fp->_IO_read_base - nread;
}
}
if (fp->_offset == _IO_pos_BAD)
goto dumb;
/* Make offset absolute, assuming current pointer is file_ptr(). */
offset += fp->_offset;
dir = _IO_seek_set;
break;
case _IO_seek_set:
break;
case _IO_seek_end:
{
struct __stat64_t64 st;
if (_IO_SYSSTAT (fp, &st) == 0 && S_ISREG (st.st_mode))
{
offset += st.st_size;
dir = _IO_seek_set;
}
else
goto dumb;
}
}
_IO_free_wbackup_area (fp);
/* At this point, dir==_IO_seek_set. */
/* If destination is within current buffer, optimize: */
if (fp->_offset != _IO_pos_BAD && fp->_IO_read_base != NULL
&& !_IO_in_backup (fp))
{
off64_t start_offset = (fp->_offset
- (fp->_IO_read_end - fp->_IO_buf_base));
if (offset >= start_offset && offset < fp->_offset)
{
_IO_setg (fp, fp->_IO_buf_base,
fp->_IO_buf_base + (offset - start_offset),
fp->_IO_read_end);
_IO_setp (fp, fp->_IO_buf_base, fp->_IO_buf_base);
_IO_wsetg (fp, fp->_wide_data->_IO_buf_base,
fp->_wide_data->_IO_buf_base,
fp->_wide_data->_IO_buf_base);
_IO_wsetp (fp, fp->_wide_data->_IO_buf_base,
fp->_wide_data->_IO_buf_base);
if (adjust_wide_data (fp, false))
goto dumb;
_IO_mask_flags (fp, 0, _IO_EOF_SEEN);
goto resync;
}
}
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);
_IO_wsetg (fp, fp->_wide_data->_IO_buf_base,
fp->_wide_data->_IO_buf_base, fp->_wide_data->_IO_buf_base);
_IO_wsetp (fp, fp->_wide_data->_IO_buf_base, fp->_wide_data->_IO_buf_base);
if (adjust_wide_data (fp, true))
goto dumb;
fp->_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->_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);
_IO_wsetg (fp, fp->_wide_data->_IO_buf_base,
fp->_wide_data->_IO_buf_base, fp->_wide_data->_IO_buf_base);
_IO_wsetp (fp, fp->_wide_data->_IO_buf_base,
fp->_wide_data->_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->_offset >= 0)
_IO_SYSSEEK (fp, fp->_offset, 0);
return offset;
}
libc_hidden_def (_IO_wfile_seekoff)
size_t
_IO_wfile_xsputn (FILE *f, const void *data, size_t n)
{
const wchar_t *s = (const wchar_t *) data;
size_t to_do = n;
int must_flush = 0;
size_t count;
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. */
count = f->_wide_data->_IO_write_end - f->_wide_data->_IO_write_ptr;
if ((f->_flags & _IO_LINE_BUF) && (f->_flags & _IO_CURRENTLY_PUTTING))
{
count = f->_wide_data->_IO_buf_end - f->_wide_data->_IO_write_ptr;
if (count >= n)
{
const wchar_t *p;
for (p = s + n; p > s; )
{
if (*--p == L'\n')
{
count = p - s + 1;
must_flush = 1;
break;
}
}
}
}
/* Then fill the buffer. */
if (count > 0)
{
if (count > to_do)
count = to_do;
if (count > 20)
{
f->_wide_data->_IO_write_ptr =
__wmempcpy (f->_wide_data->_IO_write_ptr, s, count);
s += count;
}
else
{
wchar_t *p = f->_wide_data->_IO_write_ptr;
int i = (int) count;
while (--i >= 0)
*p++ = *s++;
f->_wide_data->_IO_write_ptr = p;
}
to_do -= count;
}
if (to_do > 0)
to_do -= _IO_wdefault_xsputn (f, s, to_do);
if (must_flush
&& f->_wide_data->_IO_write_ptr != f->_wide_data->_IO_write_base)
_IO_wdo_write (f, f->_wide_data->_IO_write_base,
f->_wide_data->_IO_write_ptr
- f->_wide_data->_IO_write_base);
return n - to_do;
}
libc_hidden_def (_IO_wfile_xsputn)