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libio: Multiple fixes for open_{w}memstram (BZ#18241 and BZ#20181)
This patches fixes multiples issues on open_{w}memstream reported on both
BZ#18241 and BZ#20181:
- failed fseek does not set errno.
- negative offset in fseek fails even when resulting position is
a valid one.
- a flush after write if the current write position is not at the
end of the stream currupt data.
The main fix is on seek operation for memstream (_IO_{w}str_seekoff), where
both _IO_read_ptr and _IO_read_end pointer are updated if a write operation
has occured (similar to default file operations). Also, to calculate the
offset on both read and write pointers, a temporary value is instead of
updating the argument supplied value. Negative offset are valid if resulting
internal pointer is within the range of _IO_{read,write}_base and
_IO_{read,write}_end.
Also POSIX states that a null or wide null shall be appended to the current
buffer iff a write moves the position to a value larger than the current
lenght. Current implementation appends a null or wide null regardless
of this condition. This patch fixes it by removing the 'else' condition
on _IO_{w}mem_sync.
Checked on x86_64.
[BZ #18241]
[BZ #20181]
* libio/Makefile (test): Add tst-memstream3 and tst-wmemstream3.
* libio/memstream.c (_IO_mem_sync): Only append a null byte if
write position is at the end the buffer.
* libio/wmemstream.c (_IO_wmem_sync): Likewise.
* libio/strops.c (_IO_str_switch_to_get_mode): New function.
(_IO_str_seekoff): Set correct offset from negative displacement and
set EINVAL for invalid ones.
* libio/wstrops.c (enlarge_userbuf): Use correct function to calculate
buffer length.
(_IO_wstr_switch_to_get_mode): New function.
(_IO_wstr_seekoff): Set correct offset from negative displacement and
set EINVAL for invalid ones.
* libio/tst-memstream3.c: New file.
* libio/tst-wmemstream3.c: Likewise.
* manual/examples/memstrm.c: Remove warning when priting size_t.
This commit is contained in:
Adhemerval Zanella
committed by
Adhemerval Zanella
Adhemerval Zanella
parent
f280fa6d17
commit
645f97ced4
@ -169,7 +169,7 @@ _IO_wstr_count (_IO_FILE *fp)
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static int
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enlarge_userbuf (_IO_FILE *fp, _IO_off64_t offset, int reading)
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{
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if ((_IO_ssize_t) offset <= _IO_blen (fp))
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if ((_IO_ssize_t) offset <= _IO_wblen (fp))
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return 0;
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struct _IO_wide_data *wd = fp->_wide_data;
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@ -235,6 +235,22 @@ enlarge_userbuf (_IO_FILE *fp, _IO_off64_t offset, int reading)
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return 0;
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}
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static void
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_IO_wstr_switch_to_get_mode (_IO_FILE *fp)
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{
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if (_IO_in_backup (fp))
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fp->_wide_data->_IO_read_base = fp->_wide_data->_IO_backup_base;
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else
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{
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fp->_wide_data->_IO_read_base = fp->_wide_data->_IO_buf_base;
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if (fp->_wide_data->_IO_write_ptr > fp->_wide_data->_IO_read_end)
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fp->_wide_data->_IO_read_end = fp->_wide_data->_IO_write_ptr;
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}
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fp->_wide_data->_IO_read_ptr = fp->_wide_data->_IO_write_ptr;
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fp->_wide_data->_IO_read_end = fp->_wide_data->_IO_write_ptr;
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fp->_flags &= ~_IO_CURRENTLY_PUTTING;
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}
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_IO_off64_t
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_IO_wstr_seekoff (_IO_FILE *fp, _IO_off64_t offset, int dir, int mode)
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@ -244,15 +260,16 @@ _IO_wstr_seekoff (_IO_FILE *fp, _IO_off64_t offset, int dir, int mode)
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if (mode == 0 && (fp->_flags & _IO_TIED_PUT_GET))
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mode = (fp->_flags & _IO_CURRENTLY_PUTTING ? _IOS_OUTPUT : _IOS_INPUT);
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bool was_writing = (fp->_wide_data->_IO_write_ptr >
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fp->_wide_data->_IO_write_base
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|| _IO_in_put_mode (fp));
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if (was_writing)
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_IO_wstr_switch_to_get_mode (fp);
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if (mode == 0)
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{
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/* Don't move any pointers. But there is no clear indication what
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mode FP is in. Let's guess. */
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if (fp->_IO_file_flags & _IO_NO_WRITES)
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new_pos = fp->_wide_data->_IO_read_ptr - fp->_wide_data->_IO_read_base;
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else
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new_pos = (fp->_wide_data->_IO_write_ptr
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- fp->_wide_data->_IO_write_base);
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new_pos = (fp->_wide_data->_IO_write_ptr
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- fp->_wide_data->_IO_write_base);
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}
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else
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{
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@ -262,25 +279,32 @@ _IO_wstr_seekoff (_IO_FILE *fp, _IO_off64_t offset, int dir, int mode)
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/* Move the get pointer, if requested. */
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if (mode & _IOS_INPUT)
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{
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_IO_ssize_t base;
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switch (dir)
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{
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case _IO_seek_end:
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offset += cur_size;
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case _IO_seek_set:
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base = 0;
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break;
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case _IO_seek_cur:
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offset += (fp->_wide_data->_IO_read_ptr
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- fp->_wide_data->_IO_read_base);
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base = (fp->_wide_data->_IO_read_ptr
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- fp->_wide_data->_IO_read_base);
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break;
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default: /* case _IO_seek_set: */
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default: /* case _IO_seek_end: */
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base = cur_size;
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break;
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}
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if (offset < 0)
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return EOF;
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if ((_IO_ssize_t) offset > cur_size
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&& enlarge_userbuf (fp, offset, 1) != 0)
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_IO_ssize_t maxval = SSIZE_MAX/sizeof (wchar_t) - base;
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if (offset < -base || offset > maxval)
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{
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__set_errno (EINVAL);
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return EOF;
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}
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base += offset;
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if (base > cur_size
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&& enlarge_userbuf (fp, base, 1) != 0)
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return EOF;
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fp->_wide_data->_IO_read_ptr = (fp->_wide_data->_IO_read_base
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+ offset);
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+ base);
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fp->_wide_data->_IO_read_end = (fp->_wide_data->_IO_read_base
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+ cur_size);
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new_pos = offset;
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@ -289,26 +313,33 @@ _IO_wstr_seekoff (_IO_FILE *fp, _IO_off64_t offset, int dir, int mode)
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/* Move the put pointer, if requested. */
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if (mode & _IOS_OUTPUT)
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{
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_IO_ssize_t base;
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switch (dir)
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{
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case _IO_seek_end:
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offset += cur_size;
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case _IO_seek_set:
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base = 0;
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break;
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case _IO_seek_cur:
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offset += (fp->_wide_data->_IO_write_ptr
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- fp->_wide_data->_IO_write_base);
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base = (fp->_wide_data->_IO_write_ptr
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- fp->_wide_data->_IO_write_base);
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break;
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default: /* case _IO_seek_set: */
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default: /* case _IO_seek_end: */
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base = cur_size;
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break;
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}
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if (offset < 0)
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return EOF;
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if ((_IO_ssize_t) offset > cur_size
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&& enlarge_userbuf (fp, offset, 0) != 0)
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_IO_ssize_t maxval = SSIZE_MAX/sizeof (wchar_t) - base;
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if (offset < -base || offset > maxval)
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{
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__set_errno (EINVAL);
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return EOF;
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}
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base += offset;
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if (base > cur_size
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&& enlarge_userbuf (fp, base, 0) != 0)
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return EOF;
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fp->_wide_data->_IO_write_ptr = (fp->_wide_data->_IO_write_base
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+ offset);
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new_pos = offset;
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+ base);
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new_pos = base;
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}
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}
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return new_pos;
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