Re: [PATCH v2 01/11] 9p: linux: Fix a couple Linux assumptions

[Christian Schoenebeck <qemu_oss@crudebyte.com>]

On Montag, 22. November 2021 01:49:03 CET Will Cohen wrote:
> From: Keno Fischer <keno@alumni.harvard.edu>
> 
>  - Guard Linux only headers.
>  - Add qemu/statfs.h header to abstract over the which
>    headers are needed for struct statfs
>  - Define `ENOATTR` only if not only defined
>    (it's defined in system headers on Darwin).
> 
> Signed-off-by: Keno Fischer <keno@juliacomputing.com>
> [Michael Roitzsch: - Rebase for NixOS]
> Signed-off-by: Michael Roitzsch <reactorcontrol@icloud.com>
> [Will Cohen: - Fix headers for Alpine]
> Signed-off-by: Will Cohen <wwcohen@gmail.com>
> ---
>  fsdev/file-op-9p.h    |  2 +-
>  hw/9pfs/9p-local.c    |  2 ++
>  hw/9pfs/9p.c          |  4 ++++
>  include/qemu/statfs.h | 19 +++++++++++++++++++
>  include/qemu/xattr.h  |  4 +++-
>  5 files changed, 29 insertions(+), 2 deletions(-)
>  create mode 100644 include/qemu/statfs.h
> 
> diff --git a/fsdev/file-op-9p.h b/fsdev/file-op-9p.h
> index 8fd89f0447..16c1a9d9fe 100644
> --- a/fsdev/file-op-9p.h
> +++ b/fsdev/file-op-9p.h
> @@ -16,7 +16,7 @@
> 
>  #include <dirent.h>
>  #include <utime.h>
> -#include <sys/vfs.h>
> +#include "qemu/statfs.h"
>  #include "qemu-fsdev-throttle.h"
>  #include "p9array.h"
> 
> diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
> index 210d9e7705..1a5e3eed73 100644
> --- a/hw/9pfs/9p-local.c
> +++ b/hw/9pfs/9p-local.c
> @@ -32,10 +32,12 @@
>  #include "qemu/error-report.h"
>  #include "qemu/option.h"
>  #include <libgen.h>
> +#ifdef CONFIG_LINUX
>  #include <linux/fs.h>
>  #ifdef CONFIG_LINUX_MAGIC_H
>  #include <linux/magic.h>
>  #endif
> +#endif
>  #include <sys/ioctl.h>
> 
>  #ifndef XFS_SUPER_MAGIC
> diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> index 15b3f4d385..9c63e14b28 100644
> --- a/hw/9pfs/9p.c
> +++ b/hw/9pfs/9p.c
> @@ -32,7 +32,11 @@
>  #include "migration/blocker.h"
>  #include "qemu/xxhash.h"
>  #include <math.h>
> +#ifdef CONFIG_LINUX
>  #include <linux/limits.h>
> +#else
> +#include <limits.h>
> +#endif
> 
>  int open_fd_hw;
>  int total_open_fd;
> diff --git a/include/qemu/statfs.h b/include/qemu/statfs.h
> new file mode 100644
> index 0000000000..dde289f9bb
> --- /dev/null
> +++ b/include/qemu/statfs.h
> @@ -0,0 +1,19 @@
> +/*
> + * Host statfs header abstraction
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2, or any
> + * later version.  See the COPYING file in the top-level directory.
> + *
> + */
> +#ifndef QEMU_STATFS_H
> +#define QEMU_STATFS_H
> +
> +#ifdef CONFIG_LINUX
> +# include <sys/vfs.h>
> +#endif
> +#ifdef CONFIG_DARWIN
> +# include <sys/param.h>
> +# include <sys/mount.h>
> +#endif
> +
> +#endif

I wonder whether adding a separate header file statfs.h just for this isn't 
overkill, as this is only included once. OTOH there is already xattr.h in 
QEMU:

> diff --git a/include/qemu/xattr.h b/include/qemu/xattr.h
> index a83fe8e749..f1d0f7be74 100644
> --- a/include/qemu/xattr.h
> +++ b/include/qemu/xattr.h
> @@ -22,7 +22,9 @@
>  #ifdef CONFIG_LIBATTR
>  #  include <attr/xattr.h>
>  #else
> -#  define ENOATTR ENODATA
> +#  if !defined(ENOATTR)
> +#    define ENOATTR ENODATA
> +#  endif
>  #  include <sys/xattr.h>
>  #endif