[PATCH 6/6] Do not ignore return values of scanf/asprintf

[Peter Hutterer]

On Wed, Sep 27, 2017 at 10:58:31AM -0700, Dmitry Torokhov wrote:
> The functions are often declared as "warn unused result", which causes
> compiler time warnings. Invalid user input may also lead to not entirely
> correct utility behavior.
> 
> Signed-off-by: Dmitry Torokhov <dtor at chromium.org>

thanks, pushed all but patch 5

Cheers,
   Peter

> ---
>  evtest.c | 17 +++++++++--------
>  1 file changed, 9 insertions(+), 8 deletions(-)
> 
> diff --git a/evtest.c b/evtest.c
> index 60714c6..ffcff78 100644
> --- a/evtest.c
> +++ b/evtest.c
> @@ -714,7 +714,7 @@ static int is_event_device(const struct dirent *dir) {
>  static char* scan_devices(void)
>  {
>  	struct dirent **namelist;
> -	int i, ndev, devnum;
> +	int i, ndev, devnum, match;
>  	char *filename;
>  	int max_device = 0;
>  
> @@ -740,22 +740,23 @@ static char* scan_devices(void)
>  		fprintf(stderr, "%s:	%s\n", fname, name);
>  		close(fd);
>  
> -		sscanf(namelist[i]->d_name, "event%d", &devnum);
> -		if (devnum > max_device)
> +		match = sscanf(namelist[i]->d_name, "event%d", &devnum);
> +		if (match >= 1 && devnum > max_device)
>  			max_device = devnum;
>  
>  		free(namelist[i]);
>  	}
>  
>  	fprintf(stderr, "Select the device event number [0-%d]: ", max_device);
> -	scanf("%d", &devnum);
>  
> -	if (devnum > max_device || devnum < 0)
> +	match = scanf("%d", &devnum);
> +	if (match < 1 || devnum > max_device || devnum < 0)
>  		return NULL;
>  
> -	asprintf(&filename, "%s/%s%d",
> -		 DEV_INPUT_EVENT, EVENT_DEV_NAME,
> -		 devnum);
> +	if (asprintf(&filename, "%s/%s%d",
> +		     DEV_INPUT_EVENT, EVENT_DEV_NAME,
> +		     devnum) < 0)
> +		return NULL;
>  
>  	return filename;
>  }
> -- 
> 2.14.2.822.g60be5d43e6-goog