whois: remove pointless realloc()

[Todd C. Miller]

There's no need to realloc() a chunk of memory when you don't care
about the old contents, we don't want have to memcpy() the old
contents to the new chunk only to throw it away.
While here, use asprintf() to simplify things.

 - todd

Index: usr.bin/whois/whois.c
===================================================================
RCS file: /cvs/src/usr.bin/whois/whois.c,v
retrieving revision 1.53
diff -u -p -u -r1.53 whois.c
--- usr.bin/whois/whois.c       9 Dec 2015 19:29:49 -0000       1.53
+++ usr.bin/whois/whois.c       15 Mar 2017 15:51:58 -0000
@@ -279,11 +279,9 @@ whois(const char *query, const char *ser
 char *
 choose_server(const char *name, const char *country)
 {
-       static char *server;
+       char *server;
        const char *qhead;
-       char *nserver;
        char *ep;
-       size_t len;
        struct addrinfo hints, *res;
 
        memset(&hints, 0, sizeof(hints));
@@ -307,16 +305,13 @@ choose_server(const char *name, const ch
                        return (NICHOST);
        } else if (isdigit((unsigned char)*(++qhead)))
                return (ANICHOST);
-       len = strlen(qhead) + sizeof(QNICHOST_TAIL);
-       if ((nserver = realloc(server, len)) == NULL)
-               err(1, "realloc");
-       server = nserver;
 
        /*
         * Post-2003 ("new") gTLDs are all supposed to have "whois.nic.domain"
         * (per registry agreement), some older gTLDs also support this...
         */
-       snprintf(server, len, "whois.nic.%s", qhead);
+       if (asprintf(&server, "whois.nic.%s", qhead) == -1)
+               err(1, NULL);
 
        /* most ccTLDs don't do this, but QNICHOST/whois-servers mostly works */
        if ((strlen(qhead) == 2 ||
@@ -333,8 +328,9 @@ choose_server(const char *name, const ch
            strcasecmp(qhead, "museum") == 0 ||
             /* for others, if whois.nic.TLD doesn't exist, try whois-servers */
            getaddrinfo(server, NULL, &hints, &res) != 0)) {
-               strlcpy(server, qhead, len);
-               strlcat(server, QNICHOST_TAIL, len);
+               free(server);
+               if (asprintf(&server, "%s%s", qhead, QNICHOST_TAIL) == -1)
+                       err(1, NULL);
        }
 
        return (server);