From 645f97ced4d4b35deda3f8bde0927f898b163f5d Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Mon, 25 Jul 2016 14:54:29 -0300 Subject: 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. --- libio/wstrops.c | 89 ++++++++++++++++++++++++++++++++++++++------------------- 1 file changed, 60 insertions(+), 29 deletions(-) (limited to 'libio/wstrops.c') diff --git a/libio/wstrops.c b/libio/wstrops.c index 09fa543..0b2bec3 100644 --- a/libio/wstrops.c +++ b/libio/wstrops.c @@ -169,7 +169,7 @@ _IO_wstr_count (_IO_FILE *fp) static int enlarge_userbuf (_IO_FILE *fp, _IO_off64_t offset, int reading) { - if ((_IO_ssize_t) offset <= _IO_blen (fp)) + if ((_IO_ssize_t) offset <= _IO_wblen (fp)) return 0; struct _IO_wide_data *wd = fp->_wide_data; @@ -235,6 +235,22 @@ enlarge_userbuf (_IO_FILE *fp, _IO_off64_t offset, int reading) return 0; } +static void +_IO_wstr_switch_to_get_mode (_IO_FILE *fp) +{ + if (_IO_in_backup (fp)) + fp->_wide_data->_IO_read_base = fp->_wide_data->_IO_backup_base; + else + { + fp->_wide_data->_IO_read_base = fp->_wide_data->_IO_buf_base; + if (fp->_wide_data->_IO_write_ptr > fp->_wide_data->_IO_read_end) + fp->_wide_data->_IO_read_end = fp->_wide_data->_IO_write_ptr; + } + fp->_wide_data->_IO_read_ptr = fp->_wide_data->_IO_write_ptr; + fp->_wide_data->_IO_read_end = fp->_wide_data->_IO_write_ptr; + + fp->_flags &= ~_IO_CURRENTLY_PUTTING; +} _IO_off64_t _IO_wstr_seekoff (_IO_FILE *fp, _IO_off64_t offset, int dir, int mode) @@ -244,15 +260,16 @@ _IO_wstr_seekoff (_IO_FILE *fp, _IO_off64_t offset, int dir, int mode) if (mode == 0 && (fp->_flags & _IO_TIED_PUT_GET)) mode = (fp->_flags & _IO_CURRENTLY_PUTTING ? _IOS_OUTPUT : _IOS_INPUT); + bool was_writing = (fp->_wide_data->_IO_write_ptr > + fp->_wide_data->_IO_write_base + || _IO_in_put_mode (fp)); + if (was_writing) + _IO_wstr_switch_to_get_mode (fp); + if (mode == 0) { - /* Don't move any pointers. But there is no clear indication what - mode FP is in. Let's guess. */ - if (fp->_IO_file_flags & _IO_NO_WRITES) - new_pos = fp->_wide_data->_IO_read_ptr - fp->_wide_data->_IO_read_base; - else - new_pos = (fp->_wide_data->_IO_write_ptr - - fp->_wide_data->_IO_write_base); + new_pos = (fp->_wide_data->_IO_write_ptr + - fp->_wide_data->_IO_write_base); } else { @@ -262,25 +279,32 @@ _IO_wstr_seekoff (_IO_FILE *fp, _IO_off64_t offset, int dir, int mode) /* Move the get pointer, if requested. */ if (mode & _IOS_INPUT) { + _IO_ssize_t base; switch (dir) { - case _IO_seek_end: - offset += cur_size; + case _IO_seek_set: + base = 0; break; case _IO_seek_cur: - offset += (fp->_wide_data->_IO_read_ptr - - fp->_wide_data->_IO_read_base); + base = (fp->_wide_data->_IO_read_ptr + - fp->_wide_data->_IO_read_base); break; - default: /* case _IO_seek_set: */ + default: /* case _IO_seek_end: */ + base = cur_size; break; } - if (offset < 0) - return EOF; - if ((_IO_ssize_t) offset > cur_size - && enlarge_userbuf (fp, offset, 1) != 0) + _IO_ssize_t maxval = SSIZE_MAX/sizeof (wchar_t) - base; + if (offset < -base || offset > maxval) + { + __set_errno (EINVAL); + return EOF; + } + base += offset; + if (base > cur_size + && enlarge_userbuf (fp, base, 1) != 0) return EOF; fp->_wide_data->_IO_read_ptr = (fp->_wide_data->_IO_read_base - + offset); + + base); fp->_wide_data->_IO_read_end = (fp->_wide_data->_IO_read_base + cur_size); new_pos = offset; @@ -289,26 +313,33 @@ _IO_wstr_seekoff (_IO_FILE *fp, _IO_off64_t offset, int dir, int mode) /* Move the put pointer, if requested. */ if (mode & _IOS_OUTPUT) { + _IO_ssize_t base; switch (dir) { - case _IO_seek_end: - offset += cur_size; + case _IO_seek_set: + base = 0; break; case _IO_seek_cur: - offset += (fp->_wide_data->_IO_write_ptr - - fp->_wide_data->_IO_write_base); + base = (fp->_wide_data->_IO_write_ptr + - fp->_wide_data->_IO_write_base); break; - default: /* case _IO_seek_set: */ + default: /* case _IO_seek_end: */ + base = cur_size; break; } - if (offset < 0) - return EOF; - if ((_IO_ssize_t) offset > cur_size - && enlarge_userbuf (fp, offset, 0) != 0) + _IO_ssize_t maxval = SSIZE_MAX/sizeof (wchar_t) - base; + if (offset < -base || offset > maxval) + { + __set_errno (EINVAL); + return EOF; + } + base += offset; + if (base > cur_size + && enlarge_userbuf (fp, base, 0) != 0) return EOF; fp->_wide_data->_IO_write_ptr = (fp->_wide_data->_IO_write_base - + offset); - new_pos = offset; + + base); + new_pos = base; } } return new_pos; -- cgit v1.1