[v4,07/13] io: Add FUSE-based test for fchmod

  Test all mode arguments, and that extra bits are ignored
as required by POSIX.
---
 io/Makefile          |   1 +
 io/tst-fchmod-fuse.c | 114 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 115 insertions(+)
 create mode 100644 io/tst-fchmod-fuse.c
  

Ok aside from questions about atomic accessess...
Reviewed-by: DJ Delorie <dj@redhat.com>

Florian Weimer <fweimer@redhat.com> writes:
> Test all mode arguments, and that extra bits are ignored
> as required by POSIX.
> ---
>  io/Makefile          |   1 +
>  io/tst-fchmod-fuse.c | 114 +++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 115 insertions(+)
>  create mode 100644 io/tst-fchmod-fuse.c
>
> diff --git a/io/Makefile b/io/Makefile
> +  tst-fchmod-fuse \

Ok.

> diff --git a/io/tst-fchmod-fuse.c b/io/tst-fchmod-fuse.c
> +/* FUSE-based test for fchmod.
> +   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 <support/fuse.h>
> +
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <stdio.h>
> +#include <support/check.h>
> +#include <support/support.h>
> +#include <support/xunistd.h>

Ok.

> +/* Set from do_test to indicate the expected incoming mode change request.  */
> +static _Atomic int expected_mode;

Ok.

> +static void
> +fuse_thread (struct support_fuse *f, void *closure)
> +{
> +  struct fuse_in_header *inh;
> +  while ((inh = support_fuse_next (f)) != NULL)
> +    {
> +      if (support_fuse_handle_mountpoint (f)
> +          || (inh->nodeid == 1 && support_fuse_handle_directory (f)))
> +        continue;
> +      switch (inh->opcode)
> +        {
> +        case FUSE_LOOKUP:
> +          {
> +            char *name = support_fuse_cast (LOOKUP, inh);
> +            TEST_COMPARE_STRING (name, "file");
> +            struct fuse_entry_out *out
> +              = support_fuse_prepare_entry (f, 2);
> +            out->attr.mode = S_IFREG | 0600;
> +            support_fuse_reply_prepared (f);
> +          }
> +          break;

Ok.

> +        case FUSE_OPEN:
> +          {
> +            TEST_COMPARE (inh->nodeid, 2);
> +            struct fuse_open_in *p = support_fuse_cast (OPEN, inh);
> +            TEST_COMPARE (p->flags & O_ACCMODE, O_RDWR);
> +            struct fuse_open_out out = { 0, };
> +            support_fuse_reply (f, &out, sizeof (out));
> +          }
> +          break;

Ok.

> +        case FUSE_SETATTR:
> +          {
> +            TEST_COMPARE (inh->nodeid, 2);
> +            struct fuse_setattr_in *p = support_fuse_cast (SETATTR, inh);
> +            TEST_COMPARE (p->valid , FATTR_MODE);
> +            TEST_COMPARE (p->mode, S_IFREG | expected_mode);

Atomic read?

> +            struct fuse_attr_out *out = support_fuse_prepare_attr (f);
> +            out->attr.mode = S_IFREG | p->mode;
> +            support_fuse_reply_prepared (f);
> +          }

Ok.

> +          break;
> +        case FUSE_FLUSH:
> +          support_fuse_reply_empty (f);
> +          break;
> +        default:
> +          support_fuse_reply_error (f, EIO);
> +        }
> +    }
> +}

Ok.

> +/* Test all mode values with the specified extra bits.  */
> +static void
> +test_with_bits (int fd, unsigned int extra_bits)
> +{
> +  for (int do_mode = 0; do_mode <= 07777; ++do_mode)
> +    {
> +      expected_mode = do_mode;

Atomic write?

> +      TEST_COMPARE (fchmod (fd, extra_bits | do_mode), 0);
> +    }
> +}

Ok.

> +static int
> +do_test (void)
> +{
> +  support_fuse_init ();
> +
> +  struct support_fuse *f = support_fuse_mount (fuse_thread, NULL);
> +  char *path = xasprintf ("%s/file", support_fuse_mountpoint (f));
> +  int fd = xopen (path, O_RDWR, 0600);
> +  free (path);
> +
> +  test_with_bits (fd, 0);
> +  /* POSIX requires that the extra bits are ignored.  */
> +  test_with_bits (fd, S_IFREG);
> +  test_with_bits (fd, S_IFDIR);
> +  test_with_bits (fd, ~07777);
> +
> +  xclose (fd);
> +  support_fuse_unmount (f);
> +
> +  return 0;
> +}
> +
> +#include <support/test-driver.c>

Ok.
  

* DJ Delorie:

> Ok aside from questions about atomic accessess...
> Reviewed-by: DJ Delorie <dj@redhat.com>

>> +        case FUSE_SETATTR:
>> +          {
>> +            TEST_COMPARE (inh->nodeid, 2);
>> +            struct fuse_setattr_in *p = support_fuse_cast (SETATTR, inh);
>> +            TEST_COMPARE (p->valid , FATTR_MODE);
>> +            TEST_COMPARE (p->mode, S_IFREG | expected_mode);
>
> Atomic read?

Memory is implicitly seq-cst for _Atomic object if not specified
explicitly.

Thanks,
Florian