[Mesa-dev] [PATCH] gallium: fix return value check

[Jan Vesely]

On Wed, 2016-09-07 at 17:34 +0300, Martina Kollarova wrote:
> A possible error (-1) was being lost because it was first converted
> to an
> unsigned int and only then checked.
> ---
>  src/gallium/winsys/sw/kms-dri/kms_dri_sw_winsys.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/src/gallium/winsys/sw/kms-dri/kms_dri_sw_winsys.c
> b/src/gallium/winsys/sw/kms-dri/kms_dri_sw_winsys.c
> index 07eca99..b8326fb 100644
> --- a/src/gallium/winsys/sw/kms-dri/kms_dri_sw_winsys.c
> +++ b/src/gallium/winsys/sw/kms-dri/kms_dri_sw_winsys.c
> @@ -252,18 +252,18 @@ kms_sw_displaytarget_add_from_prime(struct
> kms_sw_winsys *kms_sw, int fd,
>     if (!kms_sw_dt)
>        return NULL;
>  
> +   int lseek_ret = lseek(fd, 0, SEEK_END);

I don't think it's safe to use int here. From the man page:
       lseek(2)  uses  the type off_t.  This is a 32-bit signed type on 32-bit
       architectures, unless one compiles with

           #define _FILE_OFFSET_BITS 64

       in which case it is a 64-bit signed type.

not that I expect the file to be >2GB, but i's better to be safe (mesa uses -D_FILE_OFFSET_BITS=64)

Jan

> +   if (lseek_ret == (off_t)-1) {
> +      FREE(kms_sw_dt);
> +      return NULL;
> +   }
> +   kms_sw_dt->size = lseek_ret;
>     kms_sw_dt->ref_count = 1;
>     kms_sw_dt->handle = handle;
> -   kms_sw_dt->size = lseek(fd, 0, SEEK_END);
>     kms_sw_dt->width = width;
>     kms_sw_dt->height = height;
>     kms_sw_dt->stride = stride;
>  
> -   if (kms_sw_dt->size == (off_t)-1) {
> -      FREE(kms_sw_dt);
> -      return NULL;
> -   }
> -
>     lseek(fd, 0, SEEK_SET);
>  
>     list_add(&kms_sw_dt->link, &kms_sw->bo_list);
-- 
Jan Vesely <jv356 at scarletmail.rutgers.edu>