Add a new fwrite test for read-only streams

Ensure that fwrite() behaves correctly even when the stream is
read-only.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This commit is contained in:
Tulio Magno Quites Machado Filho 2024-09-05 15:34:29 -03:00
parent cec3aef324
commit 5d4ab106d4
2 changed files with 66 additions and 0 deletions

View File

@ -223,6 +223,7 @@ tests := \
tst-freopen64-3 \
tst-fseek \
tst-fwrite \
tst-fwrite-ro \
tst-getline \
tst-getline-enomem \
tst-gets \

View File

@ -0,0 +1,65 @@
/* Test fwrite on a read-only stream.
Copyright (C) 2024 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
<https://www.gnu.org/licenses/>. */
#include <stdio.h>
#include <support/check.h>
#include <support/temp_file.h>
#include <support/xstdio.h>
#include <support/xunistd.h>
/* A small buffer size is enough to run this test. */
#define BUFSIZE 4
static int
do_test (void)
{
int fd;
FILE *f;
struct stat64 st;
/* Create a temporary file and open it in read-only mode. */
fd = create_temp_file ("tst-fwrite-ro", NULL);
TEST_VERIFY_EXIT (fd != -1);
f = fdopen (fd, "r");
TEST_VERIFY_EXIT (f != NULL);
/* Try to write to the temporary file with nmemb = 0, then check that
fwrite returns 0. No errors are expected from this. */
TEST_COMPARE (fwrite ("a", 1, 0, f), 0);
TEST_COMPARE (ferror (f), 0);
/* Try to write to the temporary file with size = 0, then check that
fwrite returns 0. No errors are expected from this. */
TEST_COMPARE (fwrite ("a", 0, 1, f), 0);
TEST_COMPARE (ferror (f), 0);
/* Try to write a single byte to the temporary file, then check that
fwrite returns 0. Check if an error was reported. */
TEST_COMPARE (fwrite ("a", 1, 1, f), 0);
TEST_COMPARE (ferror (f), 1);
clearerr (f);
xfstat64 (fd, &st);
TEST_COMPARE (st.st_size, 0);
xfclose (f);
return 0;
}
#include <support/test-driver.c>