Re: [PATCH] util/drm: make portable

[Philippe Mathieu-Daudé]

On 7/1/20 8:03 PM, Gerd Hoffmann wrote:
> Given this isn't perforance critical at all lets avoid the non-portable
> d_type and use fstat instead to check whenever the file is a chardev.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

Reported-by: David Carlier <devnexen@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> ---
>  util/drm.c | 17 ++++++++++++-----
>  1 file changed, 12 insertions(+), 5 deletions(-)
> 
> diff --git a/util/drm.c b/util/drm.c
> index a23ff2453826..6ba87f34f4ee 100644
> --- a/util/drm.c
> +++ b/util/drm.c
> @@ -24,7 +24,8 @@ int qemu_drm_rendernode_open(const char *rendernode)
>  {
>      DIR *dir;
>      struct dirent *e;
> -    int r, fd;
> +    struct stat st;
> +    int r, fd, ret;
>      char *p;
>  
>      if (rendernode) {
> @@ -38,10 +39,6 @@ int qemu_drm_rendernode_open(const char *rendernode)
>  
>      fd = -1;
>      while ((e = readdir(dir))) {
> -        if (e->d_type != DT_CHR) {
> -            continue;
> -        }
> -
>          if (strncmp(e->d_name, "renderD", 7)) {
>              continue;
>          }
> @@ -53,6 +50,16 @@ int qemu_drm_rendernode_open(const char *rendernode)
>              g_free(p);
>              continue;
>          }
> +
> +        /* prefer fstat() over checking e->d_type == DT_CHR for
> +         * portability reasons */
> +        ret = fstat(r, &st);
> +        if (ret < 0 || (st.st_mode & S_IFMT) != S_IFCHR) {
> +            close(r);
> +            g_free(p);
> +            continue;
> +        }
> +
>          fd = r;
>          g_free(p);
>          break;
>