Re: [fsverity-utils PATCH 1/2] Remove unneeded includes

[Eric Biggers <ebiggers@kernel.org>]

On Wed, Dec 16, 2020 at 05:27:18PM +0000, luca.boccassi@gmail.com wrote:
> From: Luca Boccassi <luca.boccassi@microsoft.com>
> 
> Signed-off-by: Luca Boccassi <luca.boccassi@microsoft.com>
> ---
>  common/fsverity_uapi.h | 1 -
>  programs/cmd_enable.c  | 1 -
>  2 files changed, 2 deletions(-)
> 
> diff --git a/common/fsverity_uapi.h b/common/fsverity_uapi.h
> index 33f4415..0006c35 100644
> --- a/common/fsverity_uapi.h
> +++ b/common/fsverity_uapi.h
> @@ -10,7 +10,6 @@
>  #ifndef _UAPI_LINUX_FSVERITY_H
>  #define _UAPI_LINUX_FSVERITY_H
>  
> -#include <linux/ioctl.h>
>  #include <linux/types.h>

fsverity_uapi.h is supposed to be kept in sync with
include/uapi/linux/fsverity.h in the kernel source tree.

There's a reason why it includes <linux/ioctl.h>.  <linux/ioctl.h> provides the
_IOW() and _IOWR() macros to expand the values of FS_IOC_ENABLE_VERITY and
FS_IOC_MEASURE_VERITY.  Usually people referring to FS_IOC_* will include
<sys/ioctl.h> in order to actually call ioctl() too.  However it's not
guaranteed, so technically the header needs to include <linux/ioctl.h>.

Wrapping this include with '#ifdef _WIN32' would be better than removing it, as
then it would be clear that it's a Windows-specific modification.

However I think an even better approach would be to add empty files
win32-headers/linux/{types,ioctl.h} and add -Iwin32-headers to CPPFLAGS, so that
these headers can still be included in the Windows build without having to
modify the source files.

> diff --git a/programs/cmd_enable.c b/programs/cmd_enable.c
> index fdf26c7..14c3c17 100644
> --- a/programs/cmd_enable.c
> +++ b/programs/cmd_enable.c
> @@ -14,7 +14,6 @@
>  #include <fcntl.h>
>  #include <getopt.h>
>  #include <limits.h>
> -#include <sys/ioctl.h>
>  

This part looks fine though, as cmd_enable.c no longer directly uses an ioctl.

- Eric