[src/trunk]: src/lib/libc/rpc Do proper accounting for the extra -1 slot. Per...

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

details:   https://anonhg.NetBSD.org/src/rev/ef708f2704c5
branches:  trunk
changeset: 811749:ef708f2704c5
user:      christos <christos%NetBSD.org@localhost>
date:      Fri Nov 13 15:22:12 2015 +0000

description:
Do proper accounting for the extra -1 slot. Perhaps this is too confusing
and it would be better to just access the array with [fd + 1] instead?

diffstat:

 lib/libc/rpc/svc.c |  33 ++++++++++++++++++++-------------
 1 files changed, 20 insertions(+), 13 deletions(-)

diffs (71 lines):

diff -r 8a63ab010d21 -r ef708f2704c5 lib/libc/rpc/svc.c
--- a/lib/libc/rpc/svc.c        Fri Nov 13 13:36:54 2015 +0000
+++ b/lib/libc/rpc/svc.c        Fri Nov 13 15:22:12 2015 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: svc.c,v 1.38 2015/11/13 11:43:26 tron Exp $    */
+/*     $NetBSD: svc.c,v 1.39 2015/11/13 15:22:12 christos Exp $        */
 
 /*
  * Copyright (c) 2010, Oracle America, Inc.
@@ -37,7 +37,7 @@
 static char *sccsid = "@(#)svc.c 1.44 88/02/08 Copyr 1984 Sun Micro";
 static char *sccsid = "@(#)svc.c       2.4 88/08/11 4.0 RPCSRC";
 #else
-__RCSID("$NetBSD: svc.c,v 1.38 2015/11/13 11:43:26 tron Exp $");
+__RCSID("$NetBSD: svc.c,v 1.39 2015/11/13 15:22:12 christos Exp $");
 #endif
 #endif
 
@@ -130,34 +130,41 @@
 static bool_t
 xprt_alloc(int sock)
 {
-       int maxset;
+       int oldmaxxports, newmaxxports;
        SVCXPRT **oldxports, **newxports;
 
        if (++sock < 0)
                return FALSE;
 
-       maxset = svc_fdset_getsize(sock);
-       if (maxset == -1)
+       newmaxxports = svc_fdset_getsize(sock);
+       if (newmaxxports == -1)
                return FALSE;
 
-       if (__svc_xports != NULL && maxset <= __svc_maxxports)
+       if (__svc_xports != NULL && newmaxxports < __svc_maxxports)
                return TRUE;
 
        oldxports = __svc_xports;
-       if (oldxports != NULL)
+       oldmaxxports = __svc_maxxports;
+       if (oldxports != NULL) {
+               /* revert saving [-1] slot */
                --oldxports;
-       newxports = realloc(oldxports, maxset * sizeof(SVCXPRT *));
+               ++oldmaxxports;
+       }
+
+       /* reserve an extra slot for [-1] */
+       newmaxxports++;
+       newxports = realloc(oldxports, newmaxxports * sizeof(SVCXPRT *));
        if (newxports == NULL) {
                warn("%s: out of memory", __func__);
                return FALSE;
        }
 
-       memset(&newxports[__svc_maxxports], 0,
-           (maxset - __svc_maxxports) * sizeof(SVCXPRT *));
+       memset(&newxports[oldmaxxports], 0,
+           (newmaxxports - oldmaxxports) * sizeof(SVCXPRT *));
 
-       __svc_xports = newxports;
-       __svc_xports++;
-       __svc_maxxports = maxset;
+       /* save one slot for [-1] */
+       __svc_xports = newxports + 1;
+       __svc_maxxports = newmaxxports - 1;
 
        return TRUE;
 }