[src/trunk]: src/sbin/sysctl Instead of using strncat and re-scanning the str...

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

details:   https://anonhg.NetBSD.org/src/rev/8465fcf1d967
branches:  trunk
changeset: 768671:8465fcf1d967
user:      christos <christos%NetBSD.org@localhost>
date:      Wed Aug 24 12:15:44 2011 +0000

description:
Instead of using strncat and re-scanning the strings all the time, use and
append printf function.

diffstat:

 sbin/sysctl/sysctl.c |  49 ++++++++++++++++++++++++++++++-------------------
 1 files changed, 30 insertions(+), 19 deletions(-)

diffs (89 lines):

diff -r 95873cb649fc -r 8465fcf1d967 sbin/sysctl/sysctl.c
--- a/sbin/sysctl/sysctl.c      Wed Aug 24 11:50:28 2011 +0000
+++ b/sbin/sysctl/sysctl.c      Wed Aug 24 12:15:44 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sysctl.c,v 1.136 2011/08/03 01:58:30 christos Exp $ */
+/*     $NetBSD: sysctl.c,v 1.137 2011/08/24 12:15:44 christos Exp $ */
 
 /*-
  * Copyright (c) 2003 The NetBSD Foundation, Inc.
@@ -68,7 +68,7 @@
 #if 0
 static char sccsid[] = "@(#)sysctl.c   8.1 (Berkeley) 6/6/93";
 #else
-__RCSID("$NetBSD: sysctl.c,v 1.136 2011/08/03 01:58:30 christos Exp $");
+__RCSID("$NetBSD: sysctl.c,v 1.137 2011/08/24 12:15:44 christos Exp $");
 #endif
 #endif /* not lint */
 
@@ -554,6 +554,21 @@
        rnode->sysctl_desc = NULL;
 }
 
+static void __attribute__((__format__(__printf__, 3, 4)))
+appendprintf(char **bp, size_t *lbp, const char *fmt, ...)
+{
+       int r;
+       va_list ap;
+
+       va_start(ap, fmt);
+       r = vsnprintf(*bp, *lbp, fmt, ap);
+       va_end(ap);
+       if (r < 0 || (size_t)r > *lbp)
+               r = *lbp;
+       *bp += r;
+       *lbp -= r;
+}
+
 /*
  * ********************************************************************
  * print this node and any others underneath it
@@ -565,35 +580,31 @@
 {
        struct sysctlnode *node;
        int rc;
-       size_t ni, sz;
-       char *sp, *dp, n[20];
+       size_t ni, sz, ldp, lsp;
+       char *sp, *dp, *tsp, *tdp;
        const struct handlespec *p;
 
-       sp = &gsname[strlen(gsname)];
-       dp = &gdname[strlen(gdname)];
+       sp = tsp = &gsname[strlen(gsname)];
+       dp = tdp = &gdname[strlen(gdname)];
+       ldp = sizeof(gdname) - (dp - gdname);
+       lsp = sizeof(gsname) - (sp - gsname);
 
        if (sp != &gsname[0] && dp == &gdname[0]) {
                /*
                 * aw...shucks.  now we must play catch up
                 */
-               for (ni = 0; ni < namelen; ni++) {
-                       (void)snprintf(n, sizeof(n), "%d", name[ni]);
-                       if (ni > 0)
-                               strncat(gdname, ".", sizeof(gdname));
-                       strncat(gdname, n, sizeof(gdname));
-               }
+               for (ni = 0; ni < namelen; ni++)
+                       appendprintf(&tdp, &ldp, "%s%d", ni > 0 ? "." : "",
+                           name[ni]);
        }
 
        if (pnode == NULL)
                pnode = &my_root;
        else if (add) {
-               snprintf(n, sizeof(n), "%d", pnode->sysctl_num);
-               if (namelen > 1) {
-                       strncat(gsname, sep, sizeof(gsname));
-                       strncat(gdname, ".", sizeof(gdname));
-               }
-               strncat(gsname, pnode->sysctl_name, sizeof(gsname));
-               strncat(gdname, n, sizeof(gdname));
+               appendprintf(&tsp, &lsp, "%s%s", namelen > 1 ? sep : "", 
+                       pnode->sysctl_name);
+               appendprintf(&tdp, &ldp, "%s%d", namelen > 1 ? "." : "", 
+                       pnode->sysctl_num);
        }
 
        if (Mflag && pnode != &my_root) {