[src/trunk]: src/usr.bin/w Don't overwrite host_buf as x might be pointing to...

[kim <kim%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/3f44fc7619b6
branches:  trunk
changeset: 973592:3f44fc7619b6
user:      kim <kim%NetBSD.org@localhost>
date:      Sat Jul 04 23:30:31 2020 +0000

description:
Don't overwrite host_buf as x might be pointing to wanted data in it

diffstat:

 usr.bin/w/w.c |  22 ++++++++++++----------
 1 files changed, 12 insertions(+), 10 deletions(-)

diffs (63 lines):

diff -r 9017f10a353d -r 3f44fc7619b6 usr.bin/w/w.c
--- a/usr.bin/w/w.c     Sat Jul 04 23:24:10 2020 +0000
+++ b/usr.bin/w/w.c     Sat Jul 04 23:30:31 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: w.c,v 1.86 2020/06/30 15:02:55 kim Exp $       */
+/*     $NetBSD: w.c,v 1.87 2020/07/04 23:30:31 kim Exp $       */
 
 /*-
  * Copyright (c) 1980, 1991, 1993, 1994
@@ -39,7 +39,7 @@
 #if 0
 static char sccsid[] = "@(#)w.c        8.6 (Berkeley) 6/30/94";
 #else
-__RCSID("$NetBSD: w.c,v 1.86 2020/06/30 15:02:55 kim Exp $");
+__RCSID("$NetBSD: w.c,v 1.87 2020/07/04 23:30:31 kim Exp $");
 #endif
 #endif /* not lint */
 
@@ -621,7 +621,7 @@
 fixhost(struct entry *ep)
 {
        char host_buf[sizeof(ep->host)];
-       char *p, *x, *m;
+       char *p, *r, *x, *m;
        struct hostent *hp;
        union {
                struct in_addr l4;
@@ -649,26 +649,28 @@
                } else
                        x = NULL;
        }
+
        int af = m ? AF_INET6 : AF_INET;
        size_t alen = m ? sizeof(l.l6) : sizeof(l.l4);
        if (!nflag && inet_pton(af, p, &l) &&
            (hp = gethostbyaddr((char *)&l, alen, af)))
-               strlcpy(host_buf, hp->h_name, sizeof(host_buf));
+               r = hp->h_name;
+       else
+               r = host_buf;
 
        if (domain[0] != '\0') {
-               p = host_buf;
-               p += strlen(host_buf);
+               p = r;
+               p += strlen(r);
                p -= strlen(domain);
-               if (p > host_buf &&
+               if (p > r &&
                    strcasecmp(p, domain) == 0)
                        *p = '\0';
        }
 
        if (x)
-               (void)snprintf(ep->host, sizeof(ep->host), "%s:%s", host_buf,
-                   x);
+               (void)snprintf(ep->host, sizeof(ep->host), "%s:%s", r, x);
        else
-               strlcpy(ep->host, host_buf, sizeof(ep->host));
+               strlcpy(ep->host, r, sizeof(ep->host));
 }
 
 static void