[src/trunk]: src/usr.bin/netstat re-do the previous to avoid malloc/free on t...

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

details:   https://anonhg.NetBSD.org/src/rev/7ffc00db2810
branches:  trunk
changeset: 350798:7ffc00db2810
user:      mrg <mrg%NetBSD.org@localhost>
date:      Sun Jan 22 04:52:04 2017 +0000

description:
re-do the previous to avoid malloc/free on the same size every iteration.

with this, or the previous, 'netstat -b 1' no longer leaks memory in
-current (or any older release using sysctl for this.)

diffstat:

 usr.bin/netstat/if.c |  30 ++++++++++++++++++++----------
 1 files changed, 20 insertions(+), 10 deletions(-)

diffs (82 lines):

diff -r 9e89e2ea3eff -r 7ffc00db2810 usr.bin/netstat/if.c
--- a/usr.bin/netstat/if.c      Sun Jan 22 04:26:31 2017 +0000
+++ b/usr.bin/netstat/if.c      Sun Jan 22 04:52:04 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if.c,v 1.92 2017/01/22 04:26:31 christos Exp $ */
+/*     $NetBSD: if.c,v 1.93 2017/01/22 04:52:04 mrg Exp $      */
 
 /*
  * Copyright (c) 1983, 1988, 1993
@@ -34,7 +34,7 @@
 #if 0
 static char sccsid[] = "from: @(#)if.c 8.2 (Berkeley) 2/21/94";
 #else
-__RCSID("$NetBSD: if.c,v 1.92 2017/01/22 04:26:31 christos Exp $");
+__RCSID("$NetBSD: if.c,v 1.93 2017/01/22 04:52:04 mrg Exp $");
 #endif
 #endif /* not lint */
 
@@ -169,7 +169,9 @@
 {
        struct if_msghdr *ifm;
        int mib[6] = { CTL_NET, AF_ROUTE, 0, 0, NET_RT_IFLIST, 0 };
-       char *buf = NULL, *next, *lim, *cp;
+       static char *buf = NULL;
+       static size_t olen;
+       char *next, *lim, *cp;
        struct rt_msghdr *rtm;
        struct ifa_msghdr *ifam;
        struct if_data *ifd = NULL;
@@ -183,8 +185,12 @@
 
        if (prog_sysctl(mib, 6, NULL, &len, NULL, 0) == -1)
                err(1, "sysctl");
-       if ((buf = malloc(len)) == NULL)
-               err(1, NULL);
+       if (len > olen) {
+               free(buf);
+               if ((buf = malloc(len)) == NULL)
+                       err(1, NULL);
+               olen = len;
+       }
        if (prog_sysctl(mib, 6, buf, &len, NULL, 0) == -1)
                err(1, "sysctl");
 
@@ -269,7 +275,6 @@
                printf("%-*.*s %-5" PRIu64 " ", n, n, name, ifd->ifi_mtu);
                print_addr(ifindex, rti_info[rtax], rti_info, ifd, NULL);
        }
-       free(buf);
 }
 
 union ifaddr_u {
@@ -1058,14 +1063,20 @@
        struct if_data *ifd = NULL;
        struct sockaddr *sa, *rti_info[RTAX_MAX];
        struct sockaddr_dl *sdl;
-       char *buf, *next, *lim;
+       static char *buf = NULL;
+       static size_t olen;
+       char *next, *lim;
        char name[IFNAMSIZ];
        size_t len;
 
        if (prog_sysctl(mib, 6, NULL, &len, NULL, 0) == -1)
                err(1, "sysctl");
-       if ((buf = malloc(len)) == NULL)
-               err(1, NULL);
+       if (len > olen) {
+               free(buf);
+               if ((buf = malloc(len)) == NULL)
+                       err(1, NULL);
+               olen = len;
+       }
        if (prog_sysctl(mib, 6, buf, &len, NULL, 0) == -1)
                err(1, "sysctl");
 
@@ -1127,5 +1138,4 @@
                ip_cur.ift_co = ifd->ifi_collisions;
                ip_cur.ift_dr = ifd->ifi_iqdrops;
        }
-       free(buf);
 }