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Re: [PATCH] nss: getent: Print IPv6 scope ID for ahosts/ahostsv6 if available



On 01/02/2019 14:38, Florian Weimer wrote:
> * Adhemerval Zanella:
> 
>> On 31/01/2019 16:00, Florian Weimer wrote:
>>> 2019-01-31  Florian Weimer  <fweimer@redhat.com>
>>>
>>> 	* nss/getent.c (ahosts_keys_int): Include IPv6 scope ID in output.
>>>
>>> diff --git a/nss/getent.c b/nss/getent.c
>>> index f25de8f1fc..1159ba2636 100644
>>> --- a/nss/getent.c
>>> +++ b/nss/getent.c
>>> @@ -393,14 +393,24 @@ ahosts_keys_int (int af, int xflags, int number, char *key[])
>>>  		  sockstr = sockbuf;
>>>  		}
>>>  
>>> +	      char scope_buf[3 * sizeof (unsigned long long int) + 2];
>>> +	      struct sockaddr_in6 *addr6
>>> +		= (struct sockaddr_in6 *) runp->ai_addr;
>>> +	      if (runp->ai_family != AF_INET6 || addr6->sin6_scope_id == 0)
>>> +		/* No scope ID present.  */
>>> +		scope_buf[0] = '\0';
>>> +	      else
>>> +		snprintf (scope_buf, sizeof (scope_buf), "%%%llu",
>>> +			  (unsigned long long int) addr6->sin6_scope_id);
>>
>> sin6_scope_id is defines as uint32_t regardless, why not use PRIu32?
> 
> Fair enough.  I also had to change the way the padding is produced.
> 
> Thanks,
> Florian
> 
> nss: getent: Print IPv6 scope ID for ahosts/ahostsv6 if available
> 
> 2019-02-01  Florian Weimer  <fweimer@redhat.com>
> 
> 	* nss/getent.c (ahosts_keys_int): Include IPv6 scope ID in output.
> 
> diff --git a/nss/getent.c b/nss/getent.c
> index f25de8f1fc..892748656b 100644
> --- a/nss/getent.c
> +++ b/nss/getent.c
> @@ -40,6 +40,7 @@
>  #include <netinet/in.h>
>  #include <sys/socket.h>
>  #include <scratch_buffer.h>
> +#include <inttypes.h>
>  
>  /* Get libc version number.  */
>  #include <version.h>
> @@ -393,15 +394,30 @@ ahosts_keys_int (int af, int xflags, int number, char *key[])
>  		  sockstr = sockbuf;
>  		}
>  
> +	      char scope[3 * sizeof (uint32_t) + 2];

I would prefer something more explicit as:

  /* It requires to hold a uint32_t plus a '%'.  */
  cat scope[((CHAR_BIT * sizeof(uint32_t) / 3) + 3) + 1];

But I don't have a strong opinion here.

> +	      struct sockaddr_in6 *addr6
> +		= (struct sockaddr_in6 *) runp->ai_addr;
> +	      if (runp->ai_family != AF_INET6 || addr6->sin6_scope_id == 0)
> +		/* No scope ID present.  */
> +		scope[0] = '\0';
> +	      else
> +		snprintf (scope, sizeof (scope), "%%%" PRIu32,
> +			  addr6->sin6_scope_id);
> +
>  	      char buf[INET6_ADDRSTRLEN];
> -	      printf ("%-15s %-6s %s\n",
> -		      inet_ntop (runp->ai_family,
> -				 runp->ai_family == AF_INET
> -				 ? (void *) &((struct sockaddr_in *) runp->ai_addr)->sin_addr
> -				 : (void *) &((struct sockaddr_in6 *) runp->ai_addr)->sin6_addr,
> -				 buf, sizeof (buf)),
> -		      sockstr,
> -		      runp->ai_canonname ?: "");
> +	      if (inet_ntop (runp->ai_family,
> +			     runp->ai_family == AF_INET
> +			     ? (void *) &((struct sockaddr_in *) runp->ai_addr)->sin_addr
> +			     : &addr6->sin6_addr,
> +			     buf, sizeof (buf)) == NULL)
> +		strcpy (buf, "<invalid>");
> +
> +	      int pad = 15 - strlen (buf) - strlen (scope);
> +	      if (pad < 0)
> +		pad = 0;

Not fun of the magic constant, but it came from original code anyway.

> +
> +	      printf ("%s%-*s %-6s %s\n",
> +		      buf, pad, scope, sockstr, runp->ai_canonname ?: "");

Do we need to print the scope for invalid address as well?

>  
>  	      runp = runp->ai_next;
>  	    }
> 


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