332 lines
11 KiB
C
332 lines
11 KiB
C
/*
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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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* $FreeBSD$
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*
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*/
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/mman.h> /* For mmap() */
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#include <rpc/rpc.h>
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#include <syslog.h>
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#include <stdlib.h>
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#include "statd.h"
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FileLayout *status_info; /* Pointer to the 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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/* 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 sync_file(void)
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{
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if (msync((void *)status_info, 0, 0) < 0)
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{
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syslog(LOG_ERR, "msync() failed: %s", strerror(errno));
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}
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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 *find_host(char *hostname, 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; i++, hp++)
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{
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if (!strncasecmp(hostname, hp->hostname, SM_MAXSTRLEN))
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{
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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) return (result);
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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 reqd */
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if (!spare_slot)
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{
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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) + sizeof(HostInfo);
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if (desired_size > status_file_len)
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{
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/* Extend file by writing 1 byte of junk at the 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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{
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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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/* 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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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 init_file(const char *filename)
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{
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int new_file = FALSE;
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char buf[HEADER_LEN];
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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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{
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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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errx(1, "unable to open status file %s", filename);
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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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status_info = (FileLayout *)
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mmap(NULL, 0x10000000, PROT_READ | PROT_WRITE, MAP_SHARED, status_fd, 0);
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if (status_info == (FileLayout *) MAP_FAILED)
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warn("unable to mmap() status file");
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status_file_len = lseek(status_fd, 0L, SEEK_END);
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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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if (!new_file)
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{
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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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{
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warnx("status file is corrupt");
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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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{
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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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}
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else
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{
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/* Clean-up of existing file - monitored hosts will have a pointer */
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/* to a list of clients, which refers to memory in the previous */
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/* incarnation of the program and so are meaningless now. These */
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/* pointers are zeroed and the fact that the host was previously */
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/* monitored is recorded by setting the notifyReqd flag, which will */
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/* in due course cause a SM_NOTIFY to be sent. */
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/* Note that if we crash twice in quick succession, some hosts may */
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/* already have notifyReqd set, where we didn't manage to notify */
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/* them before the second crash occurred. */
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for (i = 0; i < status_info->noOfHosts; i++)
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{
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HostInfo *this_host = &status_info->hosts[i];
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if (this_host->monList)
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{
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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 = (status_info->ourState + 2) & 0xfffffffe;
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/*???????******/ status_info->ourState++;
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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 notify_one_host(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) syslog (LOG_DEBUG, "Sending SM_NOTIFY to host %s from %s", 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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{
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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, (xdrproc_t)xdr_stat_chge, &arg,
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(xdrproc_t)xdr_void, &dummy, timeout)
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!= RPC_SUCCESS)
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{
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syslog(LOG_ERR, "Failed to contact rpc.statd at host %s", 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 notify_hosts(void)
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{
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int i;
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int attempts;
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int work_to_do = FALSE;
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HostInfo *hp;
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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 ; i--, hp++)
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{
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if (hp->notifyReqd)
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{
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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) return; /* No work found */
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pid = fork();
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if (pid == -1)
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{
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syslog(LOG_ERR, "Unable to fork notify process - %s", strerror(errno));
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return;
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}
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if (pid) return;
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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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for (attempts = 0; attempts < 44; attempts++)
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{
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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 ; i--, hp++)
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{
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if (hp->notifyReqd)
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{
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if (notify_one_host(hp->hostname))
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{
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hp->notifyReqd = FALSE;
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sync_file();
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}
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else work_to_do = TRUE;
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}
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}
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if (!work_to_do) break;
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if (attempts < 10) sleep(5);
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else if (attempts < 20) sleep(60);
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else sleep(60*60);
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}
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exit(0);
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}
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