On Wed, Jan 22, 2020 at 10:51:45AM +0100, Martijn van Duren wrote:
> Trying to wrap my head around some of the snmpd code I found this pearl
> that appears to do nothing more than warm up the room.
Do you really want to get rid of the init of snmpd_env->sc_cpustates ?
-Otto
>
> OK?
>
> martijn@
>
> Index: Makefile
> ===================================================================
> RCS file: /cvs/src/usr.sbin/snmpd/Makefile,v
> retrieving revision 1.16
> diff -u -p -r1.16 Makefile
> --- Makefile 11 May 2019 17:46:02 -0000 1.16
> +++ Makefile 22 Jan 2020 09:50:51 -0000
> @@ -3,7 +3,7 @@
> PROG= snmpd
> MAN= snmpd.8 snmpd.conf.5
> SRCS= parse.y log.c control.c snmpe.c \
> - mps.c trap.c mib.c smi.c kroute.c snmpd.c timer.c \
> + mps.c trap.c mib.c smi.c kroute.c snmpd.c \
> pf.c proc.c usm.c agentx.c traphandler.c util.c
>
> LDADD= -levent -lutil -lkvm -lcrypto
> Index: snmpd.h
> ===================================================================
> RCS file: /cvs/src/usr.sbin/snmpd/snmpd.h,v
> retrieving revision 1.86
> diff -u -p -r1.86 snmpd.h
> --- snmpd.h 2 Jan 2020 10:55:53 -0000 1.86
> +++ snmpd.h 22 Jan 2020 09:50:51 -0000
> @@ -745,9 +745,6 @@ unsigned int smi_application(struct ber
> void smi_debug_elements(struct ber_element *);
> char *smi_print_element(struct ber_element *);
>
> -/* timer.c */
> -void timer_init(void);
> -
> /* snmpd.c */
> int snmpd_socket_af(struct sockaddr_storage *, in_port_t, int);
> u_long snmpd_engine_time(void);
> Index: snmpe.c
> ===================================================================
> RCS file: /cvs/src/usr.sbin/snmpd/snmpe.c,v
> retrieving revision 1.60
> diff -u -p -r1.60 snmpe.c
> --- snmpe.c 24 Oct 2019 12:39:27 -0000 1.60
> +++ snmpe.c 22 Jan 2020 09:50:51 -0000
> @@ -103,7 +103,6 @@ snmpe_init(struct privsep *ps, struct pr
>
> kr_init();
> trap_init();
> - timer_init();
> usm_generate_keys();
>
> /* listen for incoming SNMP UDP/TCP messages */
> Index: timer.c
> ===================================================================
> RCS file: timer.c
> diff -N timer.c
> --- timer.c 28 Oct 2016 08:01:53 -0000 1.7
> +++ /dev/null 1 Jan 1970 00:00:00 -0000
> @@ -1,169 +0,0 @@
> -/* $OpenBSD: timer.c,v 1.7 2016/10/28 08:01:53 rzalamena Exp $ */
> -
> -/*
> - * Copyright (c) 2008 Reyk Floeter <[email protected]>
> - *
> - * Permission to use, copy, modify, and distribute this software for any
> - * purpose with or without fee is hereby granted, provided that the above
> - * copyright notice and this permission notice appear in all copies.
> - *
> - * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
> - * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
> - * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
> - * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
> - * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
> - * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
> - * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
> - */
> -
> -#include <sys/queue.h>
> -#include <sys/types.h>
> -#include <sys/time.h>
> -#include <sys/sched.h>
> -#include <sys/socket.h>
> -#include <sys/sysctl.h>
> -
> -#include <net/if.h>
> -#include <net/if_types.h>
> -#include <netinet/in.h>
> -#include <netinet/ip.h>
> -#include <netinet/ip_var.h>
> -#include <arpa/inet.h>
> -
> -#include <stdlib.h>
> -#include <stdio.h>
> -#include <errno.h>
> -#include <event.h>
> -#include <fcntl.h>
> -#include <string.h>
> -#include <unistd.h>
> -#include <pwd.h>
> -
> -#include "snmpd.h"
> -#include "mib.h"
> -
> -void timer_cpu(int, short, void *);
> -int percentages(int, int64_t *, int64_t *, int64_t *, int64_t *);
> -
> -static int64_t **cp_time;
> -static int64_t **cp_old;
> -static int64_t **cp_diff;
> -struct event cpu_ev;
> -
> -void
> -timer_cpu(int fd, short event, void *arg)
> -{
> - struct event *ev = (struct event *)arg;
> - struct timeval tv = { 60, 0 }; /* every 60 seconds */
> - int mib[3] = { CTL_KERN, KERN_CPTIME2, 0 }, n;
> - size_t len;
> - int64_t *cptime2;
> -
> - len = CPUSTATES * sizeof(int64_t);
> - for (n = 0; n < snmpd_env->sc_ncpu; n++) {
> - mib[2] = n;
> - cptime2 = snmpd_env->sc_cpustates + (CPUSTATES * n);
> - if (sysctl(mib, 3, cp_time[n], &len, NULL, 0) == -1)
> - continue;
> - (void)percentages(CPUSTATES, cptime2, cp_time[n],
> - cp_old[n], cp_diff[n]);
> -#ifdef DEBUG
> - log_debug("timer_cpu: cpu%d %lld%% idle in %llds", n,
> - (cptime2[CP_IDLE] > 1000 ?
> - 1000 : (cptime2[CP_IDLE] / 10)), (long long) tv.tv_sec);
> -#endif
> - }
> -
> - evtimer_add(ev, &tv);
> -}
> -
> -void
> -timer_init(void)
> -{
> - int mib[] = { CTL_HW, HW_NCPU }, i;
> - size_t len;
> -
> - len = sizeof(snmpd_env->sc_ncpu);
> - if (sysctl(mib, 2, &snmpd_env->sc_ncpu, &len, NULL, 0) == -1)
> - fatal("sysctl");
> -
> - snmpd_env->sc_cpustates = calloc(snmpd_env->sc_ncpu,
> - CPUSTATES * sizeof(int64_t));
> - cp_time = calloc(snmpd_env->sc_ncpu, sizeof(int64_t *));
> - cp_old = calloc(snmpd_env->sc_ncpu, sizeof(int64_t *));
> - cp_diff = calloc(snmpd_env->sc_ncpu, sizeof(int64_t *));
> - if (snmpd_env->sc_cpustates == NULL ||
> - cp_time == NULL || cp_old == NULL || cp_diff == NULL)
> - fatal("calloc");
> - for (i = 0; i < snmpd_env->sc_ncpu; i++) {
> - cp_time[i] = calloc(CPUSTATES, sizeof(int64_t));
> - cp_old[i] = calloc(CPUSTATES, sizeof(int64_t));
> - cp_diff[i] = calloc(CPUSTATES, sizeof(int64_t));
> - if (cp_time[i] == NULL || cp_old[i] == NULL ||
> - cp_diff[i] == NULL)
> - fatal("calloc");
> - }
> -
> - evtimer_set(&cpu_ev, timer_cpu, &cpu_ev);
> - timer_cpu(0, EV_TIMEOUT, &cpu_ev);
> -}
> -
> -/*
> - * percentages() function to calculate CPU utilization.
> - * Source code derived from the top(1) utility:
> - *
> - * Copyright (c) 1984, 1989, William LeFebvre, Rice University
> - * Copyright (c) 1989, 1990, 1992, William LeFebvre, Northwestern University
> - *
> - * Redistribution and use in source and binary forms, with or without
> - * modification, are permitted provided that the following conditions
> - * are met:
> - * 1. Redistributions of source code must retain the above copyright
> - * notice, this list of conditions and the following disclaimer.
> - * 2. Redistributions in binary form must reproduce the above copyright
> - * notice, this list of conditions and the following disclaimer in the
> - * documentation and/or other materials provided with the distribution.
> - *
> - * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
> - * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
> - * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
> - * IN NO EVENT SHALL THE AUTHOR OR HIS EMPLOYER BE LIABLE FOR ANY DIRECT,
> INDIRECT,
> - * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
> - * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
> - * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
> - * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
> - * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
> - * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> - */
> -int
> -percentages(int cnt, int64_t *out, int64_t *new, int64_t *old, int64_t
> *diffs)
> -{
> - int64_t change, total_change, *dp, half_total;
> - int i;
> -
> - /* initialization */
> - total_change = 0;
> - dp = diffs;
> -
> - /* calculate changes for each state and the overall change */
> - for (i = 0; i < cnt; i++) {
> - if ((change = *new - *old) < 0) {
> - /* this only happens when the counter wraps */
> - change = (*new - *old);
> - }
> - total_change += (*dp++ = change);
> - *old++ = *new++;
> - }
> -
> - /* avoid divide by zero potential */
> - if (total_change == 0)
> - total_change = 1;
> -
> - /* calculate percentages based on overall change, rounding up */
> - half_total = total_change / 2l;
> - for (i = 0; i < cnt; i++)
> - *out++ = ((*diffs++ * 1000 + half_total) / total_change);
> -
> - /* return the total in case the caller wants to use it */
> - return (total_change);
> -}
>
