Re: [PATCH v4] linux-user: syscall: ioctls: support DRM_IOCTL_VERSION

[Laurent Vivier]

Le 02/06/2020 à 14:00, chengang@emindsoft.com.cn a écrit :
> From: Chen Gang <chengang@emindsoft.com.cn>
> 
> Another DRM_IOCTL_* commands will be done later.
> 
> Signed-off-by: Chen Gang <chengang@emindsoft.com.cn>
> ---
>  configure                  | 10 ++++++
>  linux-user/ioctls.h        |  5 +++
>  linux-user/syscall.c       | 67 ++++++++++++++++++++++++++++++++++++++
>  linux-user/syscall_defs.h  | 15 +++++++++
>  linux-user/syscall_types.h | 11 +++++++
>  5 files changed, 108 insertions(+)
> 
> diff --git a/configure b/configure
> index e225a1e3ff..3cf28a649a 100755
> --- a/configure
> +++ b/configure
> @@ -3140,6 +3140,13 @@ if ! check_include "ifaddrs.h" ; then
>    have_ifaddrs_h=no
>  fi
>  
> +#########################################
> +# libdrm check
> +have_drm_h=no
> +if check_include "libdrm/drm.h" ; then
> +    have_drm_h=yes
> +fi
> +
>  ##########################################
>  # VTE probe
>  
> @@ -7149,6 +7156,9 @@ fi
>  if test "$have_ifaddrs_h" = "yes" ; then
>      echo "HAVE_IFADDRS_H=y" >> $config_host_mak
>  fi
> +if test "$have_drm_h" = "yes" ; then
> +  echo "HAVE_DRM_H=y" >> $config_host_mak
> +fi
>  if test "$have_broken_size_max" = "yes" ; then
>      echo "HAVE_BROKEN_SIZE_MAX=y" >> $config_host_mak
>  fi

The configure and HAVE_DRM_H look good...

> diff --git a/linux-user/ioctls.h b/linux-user/ioctls.h
> index 0defa1d8c1..f2e2fa9c87 100644
> --- a/linux-user/ioctls.h
> +++ b/linux-user/ioctls.h
> @@ -574,6 +574,11 @@
>    IOCTL_SPECIAL(SIOCDELRT, IOC_W, do_ioctl_rt,
>                  MK_PTR(MK_STRUCT(STRUCT_rtentry)))
>  
> +#ifdef HAVE_DRM_H
> +  IOCTL_SPECIAL(DRM_IOCTL_VERSION, IOC_RW, do_ioctl_drm,
> +                MK_PTR(MK_STRUCT(STRUCT_drm_version)))
> +#endif
> +
>  #ifdef TARGET_TIOCSTART
>    IOCTL_IGNORE(TIOCSTART)
>    IOCTL_IGNORE(TIOCSTOP)
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 5af55fca78..006889cea6 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -112,6 +112,9 @@
>  #include <linux/if_alg.h>
>  #include <linux/rtc.h>
>  #include <sound/asound.h>
> +#ifdef HAVE_DRM_H
> +#include <libdrm/drm.h>
> +#endif
>  #include "linux_loop.h"
>  #include "uname.h"
>  
> @@ -5275,6 +5278,70 @@ static abi_long do_ioctl_tiocgptpeer(const IOCTLEntry 
> *ie, uint8_t *buf_temp,
>  }
>  #endif
>  
> +#ifdef HAVE_DRM_H
> +
> +static inline abi_long target_to_host_drmversion(struct drm_version 
> *host_ver,
> +                                                abi_long target_addr)
> +{
> +    struct target_drm_version *target_ver;
> +
> +    if (!lock_user_struct(VERIFY_READ, target_ver, target_addr, 0)) {
> +        return -TARGET_EFAULT;
> +    }
> +    __get_user(host_ver->name_len, &target_ver->name_len);
> +    host_ver->name = host_ver->name_len ? g2h(target_ver->name) : NULL;
> +    __get_user(host_ver->date_len, &target_ver->date_len);
> +    host_ver->date = host_ver->date_len ? g2h(target_ver->date) : NULL;
> +    __get_user(host_ver->desc_len, &target_ver->desc_len);
> +    host_ver->desc = host_ver->desc_len ? g2h(target_ver->desc) : NULL;

but I think the string buffers must be locked and access rights must be
checked.

So I think you should have something like:

host_ver->name = lock_user(VERIFY_WRITE, target_ver->name,
                           target_ver->name_len, 0);
...

> +    unlock_user_struct(target_ver, target_addr, 0);
> +    return 0;
> +}
> +
> +static inline abi_long host_to_target_drmversion(abi_ulong target_addr,
> +                                                 struct drm_version 
> *host_ver)
> +{
> +    struct target_drm_version *target_ver;
> +
> +    if (!lock_user_struct(VERIFY_WRITE, target_ver, target_addr, 0)) {
> +        return -TARGET_EFAULT;
> +    }
> +    __put_user(host_ver->version_major, &target_ver->version_major);
> +    __put_user(host_ver->version_minor, &target_ver->version_minor);
> +    __put_user(host_ver->version_patchlevel, 
> &target_ver->version_patchlevel);
> +    __put_user(host_ver->name_len, &target_ver->name_len);

unlock_user(host_ver->name, target_ver->name, host_ver->name_len);
...

> +    __put_user(host_ver->date_len, &target_ver->date_len);
> +    __put_user(host_ver->desc_len, &target_ver->desc_len);
> +    unlock_user_struct(target_ver, target_addr, 0);
> +    return 0;
> +}
> +

Thanks,
Laurent