Add a new fwrite test for read-only streams
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Commit Message
From: Tulio Magno Quites Machado Filho <tuliom@redhat.com>
Ensure that fwrite() behaves correctly even when the stream is
read-only.
---
stdio-common/Makefile | 1 +
stdio-common/tst-fwrite-ro.c | 56 ++++++++++++++++++++++++++++++++++++
2 files changed, 57 insertions(+)
create mode 100644 stdio-common/tst-fwrite-ro.c
Comments
On 29/08/24 11:59, Tulio Magno Quites Machado Filho wrote:
> From: Tulio Magno Quites Machado Filho <tuliom@redhat.com>
>
> Ensure that fwrite() behaves correctly even when the stream is
> read-only.
The patch fails to apply, as indicated by CI, but it seems to due
new tests added on stdio-common/Makefile.
> ---
> stdio-common/Makefile | 1 +
> stdio-common/tst-fwrite-ro.c | 56 ++++++++++++++++++++++++++++++++++++
> 2 files changed, 57 insertions(+)
> create mode 100644 stdio-common/tst-fwrite-ro.c
>
> diff --git a/stdio-common/Makefile b/stdio-common/Makefile
> index e4f0146d2c7..315152f30df 100644
> --- a/stdio-common/Makefile
> +++ b/stdio-common/Makefile
> @@ -218,6 +218,7 @@ tests := \
> tst-fphex-wide \
> tst-fseek \
> tst-fwrite \
> + tst-fwrite-ro \
> tst-gets \
> tst-grouping \
> tst-grouping2 \
> diff --git a/stdio-common/tst-fwrite-ro.c b/stdio-common/tst-fwrite-ro.c
> new file mode 100644
> index 00000000000..cd67bf774ee
> --- /dev/null
> +++ b/stdio-common/tst-fwrite-ro.c
> @@ -0,0 +1,56 @@
> +/* 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>
> +
> +static int
> +do_test (void)
> +{
> + int fd;
> + FILE *f;
> +
> + /* Create a temporary file and open it in read-only mode. */
> + TEST_VERIFY_EXIT ((fd = create_temp_file ("tst-fwrite-ro", NULL)));
No implicit checks and this would fail if create_temp_file fails with -1.
> + TEST_VERIFY_EXIT ((f = fdopen (fd, "r")));
No implicit checks.
> +
> + /* 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);
I think you also check check that the file is actually empty.
> +
> + clearerr (f);
> + xfclose (f);
> +
> + return 0;
> +}
> +
> +#include <support/test-driver.c>
@@ -218,6 +218,7 @@ tests := \
tst-fphex-wide \
tst-fseek \
tst-fwrite \
+ tst-fwrite-ro \
tst-gets \
tst-grouping \
tst-grouping2 \
new file mode 100644
@@ -0,0 +1,56 @@
+/* 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>
+
+static int
+do_test (void)
+{
+ int fd;
+ FILE *f;
+
+ /* Create a temporary file and open it in read-only mode. */
+ TEST_VERIFY_EXIT ((fd = create_temp_file ("tst-fwrite-ro", NULL)));
+ TEST_VERIFY_EXIT ((f = fdopen (fd, "r")));
+
+ /* 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);
+ xfclose (f);
+
+ return 0;
+}
+
+#include <support/test-driver.c>