NetBSD/usr.sbin/rpc.statd/statd.c

450 lines
13 KiB
C

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