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Re: [PATCH 1/2] libio: Multiple fixes for open_{w}memstram (BZ#18241 and BZ#20181)
- From: Andreas Schwab <schwab at linux-m68k dot org>
- To: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- Cc: libc-alpha at sourceware dot org
- Date: Fri, 05 Aug 2016 22:11:24 +0200
- Subject: Re: [PATCH 1/2] libio: Multiple fixes for open_{w}memstram (BZ#18241 and BZ#20181)
- Authentication-results: sourceware.org; auth=none
- References: <1470418850-22175-1-git-send-email-adhemerval.zanella@linaro.org>
On Fr, Aug 05 2016, Adhemerval Zanella <adhemerval.zanella@linaro.org> wrote:
> For invalid position a different return error than EOF is used so
> _IO_seekoff_unlocked can set errno accordingly.
Is that needed? Can't the functions set errno themselves?
> diff --git a/libio/tst-memstream3.c b/libio/tst-memstream3.c
> new file mode 100644
> index 0000000..ce4e60d
> --- /dev/null
> +++ b/libio/tst-memstream3.c
> @@ -0,0 +1,155 @@
> +/* Test for open_memstream implementation.
> + Copyright (C) 2016 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
> + <http://www.gnu.org/licenses/>. */
> +
> +#include <mcheck.h>
> +#include <stdio.h>
> +#include <errno.h>
> +
> +
> +#ifndef CHAR_T
> +# define CHAR_T char
> +# define W(o) o
> +# define OPEN_MEMSTREAM open_memstream
> +# define PRINTF printf
> +# define FWRITE fwrite
> +# define FPUTC fputc
> +# define STRCMP strcmp
> +#endif
> +
> +#define S(s) S1 (s)
> +#define S1(s) #s
> +
> +static void
> +mcheck_abort (enum mcheck_status ev)
> +{
> + printf ("mecheck failed with status %d\n", (int) ev);
> + exit (1);
> +}
> +
> +#define LOC2(l) "error: " __FILE__ ":" #l
> +#define LOC1(l) LOC2(l)
> +#define ERROR_RET1(...) \
> + { printf(LOC1(__LINE__) ": " __VA_ARGS__); return 1; }
Putting __FILE__ into the format string is unsafe, it could contain %.
> @@ -262,25 +279,29 @@ _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
> + base = (fp->_wide_data->_IO_read_ptr
> - fp->_wide_data->_IO_read_base);
Reindent.
> 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;
Space around operator.
> @@ -289,26 +310,30 @@ _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
> + base = (fp->_wide_data->_IO_write_ptr
> - fp->_wide_data->_IO_write_base);
Reindent.
> 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;
Space around operator.
Andreas.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."