Re: [PATCH v5] selftests/landlock: Skip overlayfs tests not supported

[Mickaël Salaün <mic@xxxxxxxxxxx>]

On 26/09/2022 16:23, Jeff Xu wrote:
> On Thu, Aug 25, 2022 at 1:23 AM Mickaël Salaün <mic@xxxxxxxxxxx> wrote:
> > As discussed for the v4, the next version of this patch needs a
> > TEST_F_FORK() fix.
> I can make TEST_F_FORK() to be skipped when SKIP() is called
> in FIXTURE_SETUP(), but this makes FIXTURE_TEARDOWN()
> complicated, because SKIP() can be called after any resource
> creation failure in the FIXTURE_SETUP().
>
> Another (better) option:  add generic FIXTURE_CONFIG_CHECK()
> FIXTURE_CONFIG_CHECK() checks the runtime configuration for
> current FIXTURE, if the configuration is not met, the whole test will be
> skipped, including FIXTURE_SETUP()/TEARDOWN(), TEST_F_FORK(),
> so there is no resource clear up issue after test.

This looks like a good idea. What do you think Shuah?


> > Please add a link to the previous patch (lore.kernel.org) for each new
> > version.
> >
> >
> > On 24/08/2022 03:58, jeffxu@xxxxxxxxxxxx wrote:
> > > From: Jeff Xu <jeffxu@xxxxxxxxxxxx>
> > >
> > > overlayfs can be disabled in the kernel configuration (which is the case
> > > for chromeOS), causing related tests to fail.  Skip such tests when an
> > > overlayfs mount operation failed because the running kernel doesn't
> > > support this file system.
> > >
> > > Signed-off-by: Jeff Xu <jeffxu@xxxxxxxxxxxx>
> > > Reviewed-by: Guenter Roeck <groeck@xxxxxxxxxxxx>
> > > ---
> > >    tools/testing/selftests/landlock/fs_test.c | 54 ++++++++++++++++++++--
> > >    1 file changed, 51 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c
> > > index 21a2ce8fa739..645304d9fe98 100644
> > > --- a/tools/testing/selftests/landlock/fs_test.c
> > > +++ b/tools/testing/selftests/landlock/fs_test.c
> > > @@ -11,6 +11,7 @@
> > >    #include <fcntl.h>
> > >    #include <linux/landlock.h>
> > >    #include <sched.h>
> > > +#include <stdio.h>
> > >    #include <string.h>
> > >    #include <sys/capability.h>
> > >    #include <sys/mount.h>
> > > @@ -169,6 +170,42 @@ static int remove_path(const char *const path)
> > >        return err;
> > >    }
> > >
> > > +static bool fgrep(FILE *file, const char *str)
> > > +{
> > > +     char line[32];
> > > +     int str_len = strlen(str);
> > > +
> > > +     while (!feof(file)) {
> > > +             if (!fgets(line, sizeof(line), file))
> > > +                     break;
> > > +             if (strncmp(line, str, str_len))
> > > +                     continue;
> > > +
> > > +             return true;
> > > +     }
> > > +
> > > +     return false;
> > > +}
> > > +
> > > +static bool supports_overlayfs(void)
> > > +{
> > > +     bool ret;
> > > +     FILE *file = fopen("/proc/filesystems", "r");
> > > +
> > > +     /*
> > > +      * A failed attempt to open /proc/filesystems
> > > +      * implies that the file system is supported (default
> > > +      * behavior). This can help detect such unattended issue
> > > +      * (which should not happen)."
> > > +      */
> > > +     if (!file)
> > > +             return true;
> > > +
> > > +     ret = fgrep(file, "nodev\toverlay\n");
> > > +     fclose(file);
> > > +     return ret;
> > > +}
> > > +
> > >    static void prepare_layout(struct __test_metadata *const _metadata)
> > >    {
> > >        disable_caps(_metadata);
> > > @@ -3404,6 +3441,8 @@ FIXTURE(layout2_overlay) {};
> > >
> > >    FIXTURE_SETUP(layout2_overlay)
> > >    {
> > > +     int ret, err;
> > > +
> > >        prepare_layout(_metadata);
> > >
> > >        create_directory(_metadata, LOWER_BASE);
> > > @@ -3431,11 +3470,20 @@ FIXTURE_SETUP(layout2_overlay)
> > >        create_directory(_metadata, MERGE_DATA);
> > >        set_cap(_metadata, CAP_SYS_ADMIN);
> > >        set_cap(_metadata, CAP_DAC_OVERRIDE);
> > > -     ASSERT_EQ(0, mount("overlay", MERGE_DATA, "overlay", 0,
> > > -                        "lowerdir=" LOWER_DATA ",upperdir=" UPPER_DATA
> > > -                        ",workdir=" UPPER_WORK));
> > > +
> > > +     ret = mount("overlay", MERGE_DATA, "overlay", 0,
> > > +                "lowerdir=" LOWER_DATA ",upperdir=" UPPER_DATA
> > > +                ",workdir=" UPPER_WORK);
> > > +     err = errno;
> > >        clear_cap(_metadata, CAP_DAC_OVERRIDE);
> > >        clear_cap(_metadata, CAP_SYS_ADMIN);
> > > +
> > > +     if (ret == -1) {
> > > +             ASSERT_EQ(ENODEV, err);
> > > +             ASSERT_FALSE(supports_overlayfs());
> > > +             SKIP(return, "overlayfs is not supported");
> > > +     }
> > > +     ASSERT_EQ(0, ret);
> > >    }
> > >
> > >    FIXTURE_TEARDOWN(layout2_overlay)
> > >
> > > base-commit: 50cd95ac46548429e5bba7ca75cc97d11a697947