[PATCH v2 1/2] libio: Multiple fixes for open_{w}memstram (BZ#18241 and BZ#20181)
Adhemerval Zanella
adhemerval.zanella@linaro.org
Fri Sep 30 00:06:00 GMT 2016
Ping.
On 25/08/2016 12:53, Adhemerval Zanella wrote:
> Ping.
>
> On 08/08/2016 17:43, Adhemerval Zanella wrote:
>> Changes from previous version:
>>
>> * Set EINVAL on _IO_{w}str_seekoff and remove INVALPOS
>> * Rewrite how to print error messages in tests to avoid put __FILE__ in
>> format string.
>> * Indentation and style fixes.
>>
>> --
>>
>> 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.
>> ---
>> ChangeLog | 20 ++++++
>> libio/Makefile | 4 +-
>> libio/memstream.c | 2 -
>> libio/strops.c | 81 +++++++++++++++--------
>> libio/tst-memstream3.c | 165 ++++++++++++++++++++++++++++++++++++++++++++++
>> libio/tst-wmemstream3.c | 44 +++++++++++++
>> libio/wmemstream.c | 2 -
>> libio/wstrops.c | 89 +++++++++++++++++--------
>> manual/examples/memstrm.c | 4 +-
>> 9 files changed, 348 insertions(+), 63 deletions(-)
>> create mode 100644 libio/tst-memstream3.c
>> create mode 100644 libio/tst-wmemstream3.c
>>
>> diff --git a/ChangeLog b/ChangeLog
>> index 205da06..28d9012 100644
>> --- a/ChangeLog
>> +++ b/ChangeLog
>> @@ -1,3 +1,23 @@
>> +2016-08-05 Adhemerval Zanella <adhemerval.zanella@linaro.org>
>> +
>> + [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.
>> +
>> 2016-08-05 Torvald Riegel <triegel@redhat.com>
>>
>> * include/atomic.h (atomic_exchange_relaxed): New.
>> diff --git a/libio/Makefile b/libio/Makefile
>> index 12589f2..0c7751c 100644
>> --- a/libio/Makefile
>> +++ b/libio/Makefile
>> @@ -56,8 +56,8 @@ tests = tst_swprintf tst_wprintf tst_swscanf tst_wscanf tst_getwc tst_putwc \
>> tst-mmap-eofsync tst-mmap-fflushsync bug-mmap-fflush \
>> tst-mmap2-eofsync tst-mmap-offend bug-fopena+ bug-wfflush \
>> bug-ungetc2 bug-ftell bug-ungetc3 bug-ungetc4 tst-fopenloc2 \
>> - tst-memstream1 tst-memstream2 \
>> - tst-wmemstream1 tst-wmemstream2 \
>> + tst-memstream1 tst-memstream2 tst-memstream3 \
>> + tst-wmemstream1 tst-wmemstream2 tst-wmemstream3 \
>> bug-memstream1 bug-wmemstream1 \
>> tst-setvbuf1 tst-popen1 tst-fgetwc bug-wsetpos tst-fseek \
>> tst-fwrite-error tst-ftell-partial-wide tst-ftell-active-handler \
>> diff --git a/libio/memstream.c b/libio/memstream.c
>> index e20b9c2..f1e8d58 100644
>> --- a/libio/memstream.c
>> +++ b/libio/memstream.c
>> @@ -112,8 +112,6 @@ _IO_mem_sync (_IO_FILE *fp)
>> _IO_str_overflow (fp, '\0');
>> --fp->_IO_write_ptr;
>> }
>> - else
>> - *fp->_IO_write_ptr = '\0';
>>
>> *mp->bufloc = fp->_IO_write_base;
>> *mp->sizeloc = fp->_IO_write_ptr - fp->_IO_write_base;
>> diff --git a/libio/strops.c b/libio/strops.c
>> index 2ba3704..1bb8a77 100644
>> --- a/libio/strops.c
>> +++ b/libio/strops.c
>> @@ -230,6 +230,21 @@ enlarge_userbuf (_IO_FILE *fp, _IO_off64_t offset, int reading)
>> return 0;
>> }
>>
>> +static void
>> +_IO_str_switch_to_get_mode (_IO_FILE *fp)
>> +{
>> + if (_IO_in_backup (fp))
>> + fp->_IO_read_base = fp->_IO_backup_base;
>> + else
>> + {
>> + fp->_IO_read_base = fp->_IO_buf_base;
>> + if (fp->_IO_write_ptr > fp->_IO_read_end)
>> + fp->_IO_read_end = fp->_IO_write_ptr;
>> + }
>> + fp->_IO_read_ptr = fp->_IO_read_end = fp->_IO_write_ptr;
>> +
>> + fp->_flags &= ~_IO_CURRENTLY_PUTTING;
>> +}
>>
>> _IO_off64_t
>> _IO_str_seekoff (_IO_FILE *fp, _IO_off64_t offset, int dir, int mode)
>> @@ -239,14 +254,14 @@ _IO_str_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->_IO_write_ptr > fp->_IO_write_base
>> + || _IO_in_put_mode (fp));
>> + if (was_writing)
>> + _IO_str_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->_IO_read_ptr - fp->_IO_read_base;
>> - else
>> - new_pos = fp->_IO_write_ptr - fp->_IO_write_base;
>> + new_pos = fp->_IO_read_ptr - fp->_IO_read_base;
>> }
>> else
>> {
>> @@ -256,48 +271,62 @@ _IO_str_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->_IO_read_ptr - fp->_IO_read_base;
>> + base = fp->_IO_read_ptr - fp->_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 - 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->_IO_read_ptr = fp->_IO_read_base + offset;
>> + fp->_IO_read_ptr = fp->_IO_read_base + base;
>> fp->_IO_read_end = fp->_IO_read_base + cur_size;
>> - new_pos = offset;
>> + new_pos = base;
>> }
>>
>> /* 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->_IO_write_ptr - fp->_IO_write_base;
>> + base = fp->_IO_write_ptr - fp->_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 - 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->_IO_write_ptr = fp->_IO_write_base + offset;
>> - new_pos = offset;
>> + fp->_IO_write_ptr = fp->_IO_write_base + base;
>> + new_pos = base;
>> }
>> }
>> return new_pos;
>> diff --git a/libio/tst-memstream3.c b/libio/tst-memstream3.c
>> new file mode 100644
>> index 0000000..34b04e5
>> --- /dev/null
>> +++ b/libio/tst-memstream3.c
>> @@ -0,0 +1,165 @@
>> +/* 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 <stdarg.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);
>> +}
>> +
>> +static void
>> +error_printf (int line, const char *fmt, ...)
>> +{
>> + va_list ap;
>> +
>> + printf ("error: %s:%i: ", __FILE__, line);
>> + va_start (ap, fmt);
>> + vprintf (fmt, ap);
>> + va_end (ap);
>> +}
>> +
>> +#define ERROR_RET1(...) \
>> + { error_printf(__LINE__, __VA_ARGS__); return 1; }
>> +
>> +static int
>> +do_test_bz18241 (void)
>> +{
>> + CHAR_T *buf;
>> + size_t size;
>> +
>> + FILE *fp = OPEN_MEMSTREAM (&buf, &size);
>> + if (fp == NULL)
>> + ERROR_RET1 ("%s failed\n", S(OPEN_MEMSTREAM));
>> +
>> + if (FPUTC (W('a'), fp) != W('a'))
>> + ERROR_RET1 ("%s failed (errno = %d)\n", S(FPUTC), errno);
>> + if (fflush (fp) != 0)
>> + ERROR_RET1 ("fflush failed (errno = %d)\n", errno);
>> + if (fseek (fp, -2, SEEK_SET) != -1)
>> + ERROR_RET1 ("fseek failed (errno = %d)\n", errno);
>> + if (errno != EINVAL)
>> + ERROR_RET1 ("errno != EINVAL\n");
>> + if (ftell (fp) != 1)
>> + ERROR_RET1 ("ftell failed (errno = %d)\n", errno);
>> + if (ferror (fp) != 0)
>> + ERROR_RET1 ("ferror != 0\n");
>> +
>> + if (fseek (fp, -1, SEEK_CUR) == -1)
>> + ERROR_RET1 ("fseek failed (errno = %d)\n", errno);
>> + if (ftell (fp) != 0)
>> + ERROR_RET1 ("ftell failed (errno = %d)\n", errno);
>> + if (ferror (fp) != 0)
>> + ERROR_RET1 ("ferror != 0\n");
>> + if (FPUTC (W('b'), fp) != W('b'))
>> + ERROR_RET1 ("%s failed (errno = %d)\n", S(FPUTC), errno);
>> + if (fflush (fp) != 0)
>> + ERROR_RET1 ("fflush failed (errno = %d)\n", errno);
>> +
>> + if (fclose (fp) != 0)
>> + ERROR_RET1 ("fclose failed (errno = %d\n", errno);
>> +
>> + if (STRCMP (buf, W("b")) != 0)
>> + ERROR_RET1 ("%s failed\n", S(STRCMP));
>> +
>> + free (buf);
>> +
>> + return 0;
>> +}
>> +
>> +static int
>> +do_test_bz20181 (void)
>> +{
>> + CHAR_T *buf;
>> + size_t size;
>> + size_t ret;
>> +
>> + FILE *fp = OPEN_MEMSTREAM (&buf, &size);
>> + if (fp == NULL)
>> + ERROR_RET1 ("%s failed\n", S(OPEN_MEMSTREAM));
>> +
>> + if ((ret = FWRITE (W("abc"), 1, 3, fp)) != 3)
>> + ERROR_RET1 ("%s failed (errno = %d)\n", S(FWRITE), errno);
>> +
>> + if (fseek (fp, 0, SEEK_SET) != 0)
>> + ERROR_RET1 ("fseek failed (errno = %d)\n", errno);
>> +
>> + if (FWRITE (W("z"), 1, 1, fp) != 1)
>> + ERROR_RET1 ("%s failed (errno = %d)\n", S(FWRITE), errno);
>> +
>> + if (fflush (fp) != 0)
>> + ERROR_RET1 ("fflush failed (errno = %d)\n", errno);
>> +
>> + /* Avoid truncating the buffer on close. */
>> + if (fseek (fp, 3, SEEK_SET) != 0)
>> + ERROR_RET1 ("fseek failed (errno = %d)\n", errno);
>> +
>> + if (fclose (fp) != 0)
>> + ERROR_RET1 ("fclose failed (errno = %d\n", errno);
>> +
>> + if (size != 3)
>> + ERROR_RET1 ("size != 3\n");
>> +
>> + if (buf[0] != W('z')
>> + || buf[1] != W('b')
>> + || buf[2] != W('c'))
>> + {
>> + PRINTF (W("error: buf {%c,%c,%c} != {z,b,c}\n"),
>> + buf[0], buf[1], buf[2]);
>> + return 1;
>> + }
>> +
>> + free (buf);
>> +
>> + return 0;
>> +}
>> +
>> +static int
>> +do_test (void)
>> +{
>> + int ret = 0;
>> +
>> + mcheck_pedantic (mcheck_abort);
>> +
>> + ret += do_test_bz18241 ();
>> + ret += do_test_bz20181 ();
>> +
>> + return ret;
>> +}
>> +
>> +#define TEST_FUNCTION do_test ()
>> +#include "../test-skeleton.c"
>> diff --git a/libio/tst-wmemstream3.c b/libio/tst-wmemstream3.c
>> new file mode 100644
>> index 0000000..190283a
>> --- /dev/null
>> +++ b/libio/tst-wmemstream3.c
>> @@ -0,0 +1,44 @@
>> +/* 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 <wchar.h>
>> +
>> +/* Straighforward implementation so tst-memstream3 could use check
>> + fwrite on open_memstream. */
>> +static size_t
>> +fwwrite (const void *ptr, size_t size, size_t nmemb, FILE *arq)
>> +{
>> + const wchar_t *wcs = (const wchar_t*) (ptr);
>> + for (size_t s = 0; s < size; s++)
>> + {
>> + for (size_t n = 0; n < nmemb; n++)
>> + if (fputwc (wcs[n], arq) == WEOF)
>> + return n;
>> + }
>> + return size * nmemb;
>> +}
>> +
>> +#define CHAR_T wchar_t
>> +#define W(o) L##o
>> +#define OPEN_MEMSTREAM open_wmemstream
>> +#define PRINTF wprintf
>> +#define FWRITE fwwrite
>> +#define FPUTC fputwc
>> +#define STRCMP wcscmp
>> +
>> +#include "tst-memstream3.c"
>> diff --git a/libio/wmemstream.c b/libio/wmemstream.c
>> index bf2a50b..fd01be0 100644
>> --- a/libio/wmemstream.c
>> +++ b/libio/wmemstream.c
>> @@ -112,8 +112,6 @@ _IO_wmem_sync (_IO_FILE *fp)
>> _IO_wstr_overflow (fp, '\0');
>> --fp->_wide_data->_IO_write_ptr;
>> }
>> - else
>> - *fp->_wide_data->_IO_write_ptr = '\0';
>>
>> *mp->bufloc = fp->_wide_data->_IO_write_base;
>> *mp->sizeloc = (fp->_wide_data->_IO_write_ptr
>> 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;
>> diff --git a/manual/examples/memstrm.c b/manual/examples/memstrm.c
>> index 0d443b1..5701ba1 100644
>> --- a/manual/examples/memstrm.c
>> +++ b/manual/examples/memstrm.c
>> @@ -27,10 +27,10 @@ main (void)
>> stream = open_memstream (&bp, &size);
>> fprintf (stream, "hello");
>> fflush (stream);
>> - printf ("buf = `%s', size = %d\n", bp, size);
>> + printf ("buf = `%s', size = %zu\n", bp, size);
>> fprintf (stream, ", world");
>> fclose (stream);
>> - printf ("buf = `%s', size = %d\n", bp, size);
>> + printf ("buf = `%s', size = %zu\n", bp, size);
>>
>> return 0;
>> }
>>
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