/* * 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. * * $FreeBSD$ * */ #include <err.h> #include <errno.h> #include <fcntl.h> #include <stdio.h> #include <string.h> #include <unistd.h> #include <sys/types.h> #include <sys/mman.h> /* For mmap() */ #include <rpc/rpc.h> #include <syslog.h> #include <stdlib.h> #include "statd.h" FileLayout *status_info; /* Pointer to the 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 */ /* sync_file --------------------------------------------------------------- */ /* Purpose: Packaged call of msync() to flush changes to mmap()ed file Returns: Nothing. Errors to syslog. */ void sync_file(void) { if (msync((void *)status_info, status_file_len, MS_SYNC) < 0 && msync((void *)status_info, status_file_len, MS_SYNC) < 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(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 reqd */ 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(const char *filename) { int new_file = FALSE; char buf[HEADER_LEN]; 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) errx(1, "unable to open status file %s", filename); /* 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 *) MAP_FAILED) warn("unable to mmap() status file"); 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)) ) { warnx("status file is corrupt"); 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++; } sync_file(); } /* notify_one_host --------------------------------------------------------- */ /* Purpose: Perform SM_NOTIFY procedure at specified host Returns: TRUE if success, FALSE if failed. */ static int notify_one_host(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) { int i; int attempts; int work_to_do = FALSE; HostInfo *hp; 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; if (claim_pid_file("/var/run/statd.notify.pid", 1) < 0) errx(1, "unable to claim notify pid file"); /* 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 ; 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); }