glibc/stdio-common/tst-fmemopen4.c
Adhemerval Zanella f9123b5003 libio: Update internal fmemopen position after write (BZ #20005)
Current GLIBC fmemopen fails with a simple testcase:

  char buffer[500] = "x";
  FILE *stream;
  stream = fmemopen(buffer, 500, "r+");
  fwrite("fish",sizeof(char),5,stream);
  printf("pos-1:%ld\n",ftell(stream));
  fflush(stream);
  printf("pos-2:%ld\n",ftell(stream));

It returns:

  pos-1:5
  pos-2:0

Where it should return:

  pos-1:5
  pos-2:5

This is due the internal write function does not correctly update the internal
object position state and then the seek operation returns a wrong value.  This
patch fixes it.

It fixes both BZ #20005 and BZ #19230 (marked as duplicated). A new test is
added to check for such case.

Tested on x86_64 and i686.

	* libio/fmemopen.c (fmemopen_write): Update internal position after
	write.
	* stdio-common/Makefile (tests): Add tst-fmemopen4.c.
	* stdio-common/tst-fmemopen4.c: New file..
2016-04-26 17:40:25 -03:00

72 lines
1.9 KiB
C

/* fmemopen tests for BZ#1930 and BZ#20005.
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 <assert.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
/* Check if fflush does not reset the file position. */
static int
do_test (void)
{
char buffer[500] = "x";
FILE *stream = fmemopen (buffer, sizeof (buffer), "r+");
if (stream == NULL)
{
printf ("error: fmemopen could not open stream\n");
return 1;
}
const char test[] = "test";
size_t r = fwrite (test, sizeof (char), sizeof (test), stream);
if (r != sizeof (test))
{
printf ("error: fwrite returned %zu, expected %zu\n", r, sizeof(test));
return 1;
}
r = ftell (stream);
if (r != sizeof (test))
{
printf ("error: ftell return %zu, expected %zu\n", r, sizeof(test));
return 1;
}
if (fflush (stream) != 0)
{
printf ("error: fflush failed\n");
return 1;
}
r = ftell (stream);
if (r != sizeof (test))
{
printf ("error: ftell return %zu, expected %zu\n", r, sizeof(test));
return 1;
}
return 0;
}
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"