450 lines
13 KiB
C
450 lines
13 KiB
C
/* $NetBSD: statd.c,v 1.2 1997/05/17 15:52:52 christos Exp $ */
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/*
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* Copyright (c) 1995
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* A.R. Gordon (andrew.gordon@net-tel.co.uk). All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed for the FreeBSD project
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* 4. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY ANDREW GORDON AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*/
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/* main() function for status monitor daemon. Some of the code in this */
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/* file was generated by running rpcgen /usr/include/rpcsvc/sm_inter.x */
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/* The actual program logic is in the file procs.c */
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#include <stdio.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <signal.h>
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#include <string.h>
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#include <syslog.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <sys/wait.h>
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#include <rpc/rpc.h>
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#include "statd.h"
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#ifndef lint
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static char rcsid[] = "$NetBSD: statd.c,v 1.2 1997/05/17 15:52:52 christos Exp $";
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#endif /* not lint */
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int debug = 0; /* Controls syslog() for debug msgs */
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int _rpcsvcdirty = 0; /* XXX ??? */
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FileLayout *status_info; /* Pointer to mmap()ed status file */
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static int status_fd; /* File descriptor for the open file */
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static off_t status_file_len; /* Current on-disc length of file */
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extern void sm_prog_1 __P((struct svc_req *, SVCXPRT *));
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static void handle_sigchld __P((int));
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main(argc, argv)
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int argc;
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char **argv;
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{
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SVCXPRT *transp;
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struct sigaction sa;
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int ch;
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while ((ch = getopt(argc, argv, "d")) != (-1)) {
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switch (ch) {
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case 'd':
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debug = 1;
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break;
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default:
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case '?':
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errx(1, "usage: rpc.statd [-d]");
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/* NOTREACHED */
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}
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}
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(void)pmap_unset(SM_PROG, SM_VERS);
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transp = svcudp_create(RPC_ANYSOCK);
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if (transp == NULL) {
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errx(1, "cannot create udp service.");
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/* NOTREACHED */
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}
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if (!svc_register(transp, SM_PROG, SM_VERS, sm_prog_1, IPPROTO_UDP)) {
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errx(1, "unable to register (SM_PROG, SM_VERS, udp).");
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/* NOTREACHED */
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}
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transp = svctcp_create(RPC_ANYSOCK, 0, 0);
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if (transp == NULL) {
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errx(1, "cannot create tcp service.");
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/* NOTREACHED */
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}
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if (!svc_register(transp, SM_PROG, SM_VERS, sm_prog_1, IPPROTO_TCP)) {
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errx(1, "unable to register (SM_PROG, SM_VERS, tcp).");
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/* NOTREACHED */
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}
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init_file("/var/db/statd.status");
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/*
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* Note that it is NOT sensible to run this program from inetd - the
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* protocol assumes that it will run immediately at boot time.
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*/
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daemon(0, 0);
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openlog("rpc.statd", 0, LOG_DAEMON);
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if (debug)
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syslog(LOG_INFO, "Starting - debug enabled");
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else
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syslog(LOG_INFO, "Starting");
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/* Install signal handler to collect exit status of child processes */
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sa.sa_handler = handle_sigchld;
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sigemptyset(&sa.sa_mask);
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sigaddset(&sa.sa_mask, SIGCHLD);
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sa.sa_flags = SA_RESTART;
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sigaction(SIGCHLD, &sa, NULL);
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/* Initialisation now complete - start operating */
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/*
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* notify_hosts() forks a process (if necessary) to do the
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* SM_NOTIFY calls, which may be slow.
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*/
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notify_hosts();
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svc_run(); /* Should never return */
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exit(1);
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}
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/* handle_sigchld ---------------------------------------------------------- */
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/*
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* Purpose: Catch SIGCHLD and collect process status
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* Returns: Nothing.
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* Notes: No special action required, other than to collect the
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* process status and hence allow the child to die:
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* we only use child processes for asynchronous transmission
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* of SM_NOTIFY to other systems, so it is normal for the
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* children to exit when they have done their work.
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*/
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static void
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handle_sigchld(sig)
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int sig;
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{
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int pid, status;
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pid = wait4(-1, &status, WNOHANG, (struct rusage *) 0);
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if (!pid)
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syslog(LOG_ERR, "Phantom SIGCHLD??");
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else if (status)
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syslog(LOG_ERR, "Child %d failed with status %d", pid,
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WEXITSTATUS(status));
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else if (debug)
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syslog(LOG_DEBUG, "Child %d exited OK", pid);
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}
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/* sync_file --------------------------------------------------------------- */
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/*
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* Purpose: Packaged call of msync() to flush changes to mmap()ed file
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* Returns: Nothing. Errors to syslog.
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*/
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void
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sync_file()
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{
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if (msync((void *)status_info, 0) < 0)
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syslog(LOG_ERR, "msync() failed: %s", strerror(errno));
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}
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/* find_host -------------------------------------------------------------- */
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/*
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* Purpose: Find the entry in the status file for a given host
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* Returns: Pointer to that entry in the mmap() region, or NULL.
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* Notes: Also creates entries if requested.
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* Failure to create also returns NULL.
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*/
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HostInfo *
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find_host(hostname, create)
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char *hostname;
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int create;
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{
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HostInfo *hp;
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HostInfo *spare_slot = NULL;
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HostInfo *result = NULL;
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int i;
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for (i = 0, hp = status_info->hosts; i < status_info->noOfHosts;
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i++, hp++) {
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if (!strncasecmp(hostname, hp->hostname, SM_MAXSTRLEN)) {
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result = hp;
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break;
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}
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if (!spare_slot && !hp->monList && !hp->notifyReqd)
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spare_slot = hp;
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}
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/* Return if entry found, or if not asked to create one. */
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if (result || !create)
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return (result);
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/*
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* Now create an entry, using the spare slot if one was found or
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* adding to the end of the list otherwise, extending file if req'd
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*/
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if (!spare_slot) {
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off_t desired_size;
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spare_slot = &status_info->hosts[status_info->noOfHosts];
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desired_size = ((char *)spare_slot - (char *)status_info) +
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sizeof(HostInfo);
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if (desired_size > status_file_len) {
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/* Extend file by writing 1 byte of junk at the
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* desired end pos */
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lseek(status_fd, desired_size - 1, SEEK_SET);
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i = write(status_fd, &i, 1);
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if (i < 1) {
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syslog(LOG_ERR, "Unable to extend status file");
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return (NULL);
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}
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status_file_len = desired_size;
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}
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status_info->noOfHosts++;
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}
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/*
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* Initialise the spare slot that has been found/created
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* Note that we do not msync(), since the caller is presumed to be
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* about to modify the entry further
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*/
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memset(spare_slot, 0, sizeof(HostInfo));
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strncpy(spare_slot->hostname, hostname, SM_MAXSTRLEN);
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return (spare_slot);
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}
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/* init_file -------------------------------------------------------------- */
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/*
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* Purpose: Open file, create if necessary, initialise it.
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* Returns: Nothing - exits on error
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* Notes: Called before process becomes daemon, hence logs to
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* stderr rather than syslog.
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* Opens the file, then mmap()s it for ease of access.
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* Also performs initial clean-up of the file, zeroing
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* monitor list pointers, setting the notifyReqd flag in
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* all hosts that had a monitor list, and incrementing
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* the state number to the next even value.
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*/
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void
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init_file(filename)
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char *filename;
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{
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char buf[HEADER_LEN];
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int new_file = FALSE;
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int i;
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/* try to open existing file - if not present, create one */
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status_fd = open(filename, O_RDWR);
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if ((status_fd < 0) && (errno == ENOENT)) {
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status_fd = open(filename, O_RDWR | O_CREAT, 0644);
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new_file = TRUE;
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}
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if (status_fd < 0) {
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err(1, "unable to open status file %s", filename);
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/* NOTREACHED */
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}
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/*
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* File now open. mmap() it, with a generous size to allow for
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* later growth, where we will extend the file but not re-map it.
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*/
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status_info = (FileLayout *)mmap(NULL, 0x10000000,
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PROT_READ | PROT_WRITE, MAP_SHARED, status_fd, 0);
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if (status_info == (FileLayout *)(-1)) {
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perror("rpc.statd");
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fprintf(stderr, "Unable to mmap() status file\n");
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}
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status_file_len = lseek(status_fd, 0L, SEEK_END);
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/*
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* If the file was not newly created, validate the contents, and if
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* defective, re-create from scratch.
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*/
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if (!new_file) {
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if ((status_file_len < HEADER_LEN) || (status_file_len <
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(HEADER_LEN + sizeof(HostInfo) * status_info->noOfHosts))) {
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fprintf(stderr, "rpc.statd: status file is corrupt\n");
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new_file = TRUE;
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}
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}
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/* Initialisation of a new, empty file. */
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if (new_file) {
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memset(buf, 0, sizeof(buf));
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lseek(status_fd, 0L, SEEK_SET);
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write(status_fd, buf, HEADER_LEN);
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status_file_len = HEADER_LEN;
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} else {
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/*
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* Clean-up of existing file - monitored hosts will have a
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* pointer to a list of clients, which refers to memory in
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* the previous incarnation of the program and so are
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* meaningless now. These pointers are zeroed and the fact
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* that the host was previously monitored is recorded by
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* setting the notifyReqd flag, which will in due course
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* cause a SM_NOTIFY to be sent.
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*
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* Note that if we crash twice in quick succession, some hosts
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* may already have notifyReqd set, where we didn't manage to
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* notify them before the second crash occurred.
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*/
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for (i = 0; i < status_info->noOfHosts; i++) {
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HostInfo *this_host = &status_info->hosts[i];
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if (this_host->monList) {
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this_host->notifyReqd = TRUE;
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this_host->monList = NULL;
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}
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}
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/* Select the next higher even number for the state counter */
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status_info->ourState =
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(status_info->ourState + 2) & 0xfffffffe;
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status_info->ourState++; /* XXX - ??? */
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}
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}
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/* notify_one_host --------------------------------------------------------- */
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/*
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* Purpose: Perform SM_NOTIFY procedure at specified host
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* Returns: TRUE if success, FALSE if failed.
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*/
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static int
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notify_one_host(hostname)
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char *hostname;
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{
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struct timeval timeout = {20, 0}; /* 20 secs timeout */
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CLIENT *cli;
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char dummy;
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stat_chge arg;
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char our_hostname[SM_MAXSTRLEN + 1];
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gethostname(our_hostname, sizeof(our_hostname));
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our_hostname[SM_MAXSTRLEN] = '\0';
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arg.mon_name = our_hostname;
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arg.state = status_info->ourState;
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if (debug)
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syslog(LOG_DEBUG, "Sending SM_NOTIFY to host %s from %s",
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hostname, our_hostname);
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cli = clnt_create(hostname, SM_PROG, SM_VERS, "udp");
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if (!cli) {
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syslog(LOG_ERR, "Failed to contact host %s%s", hostname,
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clnt_spcreateerror(""));
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return (FALSE);
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}
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if (clnt_call(cli, SM_NOTIFY, xdr_stat_chge, &arg, xdr_void,
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&dummy, timeout) != RPC_SUCCESS) {
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syslog(LOG_ERR, "Failed to contact rpc.statd at host %s",
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hostname);
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clnt_destroy(cli);
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return (FALSE);
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}
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clnt_destroy(cli);
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return (TRUE);
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}
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/* notify_hosts ------------------------------------------------------------ */
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/*
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* Purpose: Send SM_NOTIFY to all hosts marked as requiring it
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* Returns: Nothing, immediately - forks a process to do the work.
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* Notes: Does nothing if there are no monitored hosts.
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* Called after all the initialisation has been done -
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* logs to syslog.
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*/
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void
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notify_hosts(void)
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{
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HostInfo *hp;
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int i, attempts;
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int work_to_do = FALSE;
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pid_t pid;
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/* First check if there is in fact any work to do. */
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for (i = status_info->noOfHosts, hp = status_info->hosts; i;
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i--, hp++) {
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if (hp->notifyReqd) {
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work_to_do = TRUE;
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break;
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}
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}
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if (!work_to_do)
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return; /* No work found */
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pid = fork();
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if (pid == -1) {
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syslog(LOG_ERR, "Unable to fork notify process - %s",
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strerror(errno));
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return;
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}
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if (pid)
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return;
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/*
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* Here in the child process. We continue until all the hosts marked
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* as requiring notification have been duly notified.
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* If one of the initial attempts fails, we sleep for a while and
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* have another go. This is necessary because when we have crashed,
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* (eg. a power outage) it is quite possible that we won't be able to
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* contact all monitored hosts immediately on restart, either because
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* they crashed too and take longer to come up (in which case the
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* notification isn't really required), or more importantly if some
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* router etc. needed to reach the monitored host has not come back
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* up yet. In this case, we will be a bit late in re-establishing
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* locks (after the grace period) but that is the best we can do.
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* We try 10 times at 5 sec intervals, 10 more times at 1 minute
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* intervals, then 24 more times at hourly intervals, finally
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* giving up altogether if the host hasn't come back to life after
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* 24 hours.
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*/
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for (attempts = 0; attempts < 44; attempts++) {
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work_to_do = FALSE; /* Unless anything fails */
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for (i = status_info->noOfHosts, hp = status_info->hosts; i > 0;
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i--, hp++) {
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if (hp->notifyReqd) {
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if (notify_one_host(hp->hostname)) {
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hp->notifyReqd = FALSE;
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sync_file();
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} else
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work_to_do = TRUE;
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}
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}
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if (!work_to_do)
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break;
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if (attempts < 10)
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sleep(5);
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else
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if (attempts < 20)
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sleep(60);
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else
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sleep(60 * 60);
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}
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exit(0);
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}
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