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Re: [PATCH] nss: getent: Print IPv6 scope ID for ahosts/ahostsv6 if available
* Adhemerval Zanella:
>> @@ -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.
“3 digits per byte” is sufficiently universal that I find your longer
version not particularly illuminating. 8-/
I have added a commented about the %. New patch below.
>> + 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.
Right.
>> +
>> + 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?
No, I think the invalid address can only happen (theoretically) for an
unexpected address family from getaddrinfo.
Thanks,
Florian
nss: getent: Print IPv6 scope ID for ahosts/ahostsv6 if available
2019-02-06 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..df73d8fb29 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 +394,31 @@ ahosts_keys_int (int af, int xflags, int number, char *key[])
sockstr = sockbuf;
}
+ /* Three digits per byte, plus '%' and null terminator. */
+ char scope[3 * sizeof (uint32_t) + 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[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;
+
+ printf ("%s%-*s %-6s %s\n",
+ buf, pad, scope, sockstr, runp->ai_canonname ?: "");
runp = runp->ai_next;
}