Using nolibc on nommu 68000, something I'm trying to build[0] wanted fread() and fseek()
so I added them, they seem to work so I'm sharing them. Not sure if I need to add
tests or something? Maybe there is a reason these weren't implemented in the first place...

0 - https://github.com/FrenkelS/Doom8088ST/issues/21

Daniel Palmer (2):
  tools/nolibc: Add fread() to stdio.h
  tools/nolibc: Add fseek() to stdio.h

 tools/include/nolibc/stdio.h | 54 +++++++++++++++++++++++++++++++++++-
 1 file changed, 53 insertions(+), 1 deletion(-)

-- 
2.51.0

On 2026-01-04 17:38:35+0900, Daniel Palmer wrote:
> Using nolibc on nommu 68000, something I'm trying to build[0] wanted fread() and fseek()
> so I added them, they seem to work so I'm sharing them. Not sure if I need to add
> tests or something? Maybe there is a reason these weren't implemented in the first place...

Thanks! These look good in general, I'll reply inline with some comments.
Please also do add some tests.

> 0 - https://github.com/FrenkelS/Doom8088ST/issues/21
> 
> Daniel Palmer (2):
>   tools/nolibc: Add fread() to stdio.h
>   tools/nolibc: Add fseek() to stdio.h
> 
>  tools/include/nolibc/stdio.h | 54 +++++++++++++++++++++++++++++++++++-
>  1 file changed, 53 insertions(+), 1 deletion(-)
> 
> -- 
> 2.51.0
>

Hi Thomas,

On Sun, 4 Jan 2026 at 18:11, Thomas Weißschuh <linux@weissschuh.net> wrote:
> Please also do add some tests.

Would a single function test that exercises the new functions be
enough? Something like this:

--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -877,6 +877,45 @@ int test_file_stream(void)
       return 0;
}

+int test_file_stream_wsr(void)
+{
+       const char dataout[] = "foo";
+       const size_t datasz = sizeof(dataout);
+       char datain[datasz];
+       FILE *f;
+       int r;
+
+       f = fopen("/tmp/file_stream_test", "w+");
+       if (!f)
+               return -1;
+
+       r = fwrite(dataout, 1, datasz, f);
+       if (r != datasz)
+               goto fail;
+
+       r = fseek(f, 0, SEEK_SET);
+       if (r)
+               goto fail;
+
+       r = fread(datain, 1, datasz, f);
+       if (r != datasz)
+               goto fail;
+
+       if (memcmp(datain, dataout, datasz) != 0)
+               goto fail;
+
+       r = fclose(f);
+       if (r == EOF)
+               return -1;
+
+       return 0;
+
+fail:
+       fclose(f);
+       return -1;
+}
+

Cheers,

Daniel

On 2026-01-04 20:12:11+0900, Daniel Palmer wrote:
> Hi Thomas,
> 
> On Sun, 4 Jan 2026 at 18:11, Thomas Weißschuh <linux@weissschuh.net> wrote:
> > Please also do add some tests.
> 
> Would a single function test that exercises the new functions be
> enough? Something like this:

That example looks good. But please use O_TMPFILE for the test file, to
make the test more robust and also test fdopen().
You can also return different error numbers depending on the failure to
make debugging easier.

> --- a/tools/testing/selftests/nolibc/nolibc-test.c
> +++ b/tools/testing/selftests/nolibc/nolibc-test.c
> @@ -877,6 +877,45 @@ int test_file_stream(void)
>        return 0;
> }
> 
> +int test_file_stream_wsr(void)
> +{
> +       const char dataout[] = "foo";
> +       const size_t datasz = sizeof(dataout);
> +       char datain[datasz];
> +       FILE *f;
> +       int r;
> +
> +       f = fopen("/tmp/file_stream_test", "w+");
> +       if (!f)
> +               return -1;
> +
> +       r = fwrite(dataout, 1, datasz, f);
> +       if (r != datasz)
> +               goto fail;
> +
> +       r = fseek(f, 0, SEEK_SET);
> +       if (r)
> +               goto fail;
> +
> +       r = fread(datain, 1, datasz, f);
> +       if (r != datasz)
> +               goto fail;
> +
> +       if (memcmp(datain, dataout, datasz) != 0)
> +               goto fail;
> +
> +       r = fclose(f);
> +       if (r == EOF)
> +               return -1;
> +
> +       return 0;
> +
> +fail:
> +       fclose(f);
> +       return -1;
> +}
> +
> 
> Cheers,
> 
> Daniel

Hi Daniel,

On Sun, Jan 04, 2026 at 08:12:11PM +0900, Daniel Palmer wrote:
> Hi Thomas,
> 
> On Sun, 4 Jan 2026 at 18:11, Thomas Weißschuh <linux@weissschuh.net> wrote:
> > Please also do add some tests.
> 
> Would a single function test that exercises the new functions be
> enough? Something like this:
> 
> --- a/tools/testing/selftests/nolibc/nolibc-test.c
> +++ b/tools/testing/selftests/nolibc/nolibc-test.c
> @@ -877,6 +877,45 @@ int test_file_stream(void)
>        return 0;
> }
> 
> +int test_file_stream_wsr(void)
> +{
> +       const char dataout[] = "foo";
> +       const size_t datasz = sizeof(dataout);
> +       char datain[datasz];
> +       FILE *f;
> +       int r;
> +
> +       f = fopen("/tmp/file_stream_test", "w+");
> +       if (!f)
> +               return -1;
> +
> +       r = fwrite(dataout, 1, datasz, f);
> +       if (r != datasz)
> +               goto fail;
> +
> +       r = fseek(f, 0, SEEK_SET);
> +       if (r)
> +               goto fail;
> +
> +       r = fread(datain, 1, datasz, f);
> +       if (r != datasz)
> +               goto fail;
> +
> +       if (memcmp(datain, dataout, datasz) != 0)
> +               goto fail;
> +
> +       r = fclose(f);
> +       if (r == EOF)
> +               return -1;
> +
> +       return 0;
> +
> +fail:
> +       fclose(f);
> +       return -1;
> +}
> +

In general it's preferable when tests focus on a specific syscall or
function, so that when a failure is reported, it's easier to figure
what we broke. But I agree it's not always easy, especially when
resources are allocated and released, like here. I can hardly propose
better. Please also keep in mind that sometimes we also want to validate
certain error cases (e.g. if opening a file in read-only mode, writing
to it should fail).

Hoping this helps,
Willy