[stgt] [PATCH 1/3] str_to_val macro, improved conversion and checking of numerical args

[FUJITA Tomonori]

On Thu, 17 Nov 2011 18:31:40 +0200
Alexander Nezhinsky <alexandern at mellanox.com> wrote:

> When a numerical command line param value is out of range or contains
> garbage (both tgtd and tgtadm), this remains unchecked in many cases.
> In some of them 0 value will be used, which may lead to unpredicted or
> "silently" faulty behavior.
> 
> This fix defines a new macro str_to_val() which uses strtoull() and
> detects its errors properly, by checking
> 1) errno (range errors) and 2) comparing endptr to the original argument
> (they remain equal in case of non-numerical garbage);
> created
> 
> Signed-off-by: Alexander Nezhinsky <alexandern at mellanox.com>
> ---
>  usr/util.h |   19 +++++++++++++++++++
>  1 files changed, 19 insertions(+), 0 deletions(-)

The idea sounds good.

> diff --git a/usr/util.h b/usr/util.h
> index d4e9406..d362903 100644
> --- a/usr/util.h
> +++ b/usr/util.h
> @@ -8,6 +8,7 @@
>  #include <signal.h>
>  #include <syscall.h>
>  #include <unistd.h>
> +#include <limits.h>
>  #include <linux/types.h>
>  
>  #include "be_byteshift.h"
> @@ -138,4 +139,22 @@ struct signalfd_siginfo {
>  };
>  #endif
>  
> +#define str_to_val(str, name, val, minv, maxv)		\
> +({							\
> +	char *ptr;					\
> +	int ret = 0;					\
> +	val = (typeof(val)) strtoull(str, &ptr, 0);	\
> +	if (errno || ptr == str) {			\
> +		eprintf("%s value '%s' invalid\n",	\
> +			name ? name : "", str);		\
> +		ret = EINVAL;				\
> +	}						\
> +	else if (val < minv || val > maxv) {		\
> +		eprintf("%s value '%s' out of range\n",	\
> +			name ? name : "", str);		\
> +		ret = ERANGE;				\
> +	}						\
> +	ret;						\
> +})
> +

Can we drop "name" argument? str_to_val just returns an error and let
the callers to do what they want. opt_long_name() looks a bit hacky (I
don't think that it's a good idea to play with the internal of struct
option). Each caller can print an appropriate error message.


Thanks,
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