Re: [dpdk-dev] [PATCH] test: fix sprintf with snprintf

[Stephen Hemminger <stephen@networkplumber.org>]

On Fri,  8 Feb 2019 13:27:37 +0000
Pallantla Poornima <pallantlax.poornima@intel.com> wrote:

> diff --git a/test/test/commands.c b/test/test/commands.c
> index 94fbc310e..5aeb35498 100644
> --- a/test/test/commands.c
> +++ b/test/test/commands.c
> @@ -367,6 +367,8 @@ int commands_init(void)
>  	struct test_command *t;
>  	char *commands, *ptr;
>  	int commands_len = 0;
> +	int total_written = 0;
> +	int count = 0;
>  
>  	TAILQ_FOREACH(t, &commands_list, next) {
>  		commands_len += strlen(t->command) + 1;
> @@ -378,7 +380,10 @@ int commands_init(void)
>  
>  	ptr = commands;
>  	TAILQ_FOREACH(t, &commands_list, next) {
> -		ptr += sprintf(ptr, "%s#", t->command);
> +		count = snprintf(ptr, commands_len - total_written - 1, "%s#",
> +				t->command);
> +		ptr += count;
> +		total_written += count;

You know snprintf is dangerous in this case as well.
It returns the number of bytes that would have been written.

That is why the linux kernel introduced scnprintf.