1 /* 2 * Copyright (c) 1995 3 * A.R. Gordon (andrew.gordon@net-tel.co.uk). All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed for the FreeBSD project 16 * 4. Neither the name of the author nor the names of any co-contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY ANDREW GORDON AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * $FreeBSD$ 33 * 34 */ 35 36 #include <err.h> 37 #include <errno.h> 38 #include <fcntl.h> 39 #include <stdio.h> 40 #include <string.h> 41 #include <unistd.h> 42 #include <sys/types.h> 43 #include <sys/mman.h> /* For mmap() */ 44 #include <rpc/rpc.h> 45 #include <syslog.h> 46 #include <stdlib.h> 47 48 #include "statd.h" 49 50 FileLayout *status_info; /* Pointer to the mmap()ed status file */ 51 static int status_fd; /* File descriptor for the open file */ 52 static off_t status_file_len; /* Current on-disc length of file */ 53 54 /* sync_file --------------------------------------------------------------- */ 55 /* 56 Purpose: Packaged call of msync() to flush changes to mmap()ed file 57 Returns: Nothing. Errors to syslog. 58 */ 59 60 void sync_file(void) 61 { 62 if (msync((void *)status_info, 0, 0) < 0) 63 { 64 syslog(LOG_ERR, "msync() failed: %s", strerror(errno)); 65 } 66 } 67 68 /* find_host -------------------------------------------------------------- */ 69 /* 70 Purpose: Find the entry in the status file for a given host 71 Returns: Pointer to that entry in the mmap() region, or NULL. 72 Notes: Also creates entries if requested. 73 Failure to create also returns NULL. 74 */ 75 76 HostInfo *find_host(char *hostname, int create) 77 { 78 HostInfo *hp; 79 HostInfo *spare_slot = NULL; 80 HostInfo *result = NULL; 81 int i; 82 83 for (i = 0, hp = status_info->hosts; i < status_info->noOfHosts; i++, hp++) 84 { 85 if (!strncasecmp(hostname, hp->hostname, SM_MAXSTRLEN)) 86 { 87 result = hp; 88 break; 89 } 90 if (!spare_slot && !hp->monList && !hp->notifyReqd) 91 spare_slot = hp; 92 } 93 94 /* Return if entry found, or if not asked to create one. */ 95 if (result || !create) return (result); 96 97 /* Now create an entry, using the spare slot if one was found or */ 98 /* adding to the end of the list otherwise, extending file if reqd */ 99 if (!spare_slot) 100 { 101 off_t desired_size; 102 spare_slot = &status_info->hosts[status_info->noOfHosts]; 103 desired_size = ((char*)spare_slot - (char*)status_info) + sizeof(HostInfo); 104 if (desired_size > status_file_len) 105 { 106 /* Extend file by writing 1 byte of junk at the desired end pos */ 107 lseek(status_fd, desired_size - 1, SEEK_SET); 108 i = write(status_fd, &i, 1); 109 if (i < 1) 110 { 111 syslog(LOG_ERR, "Unable to extend status file"); 112 return (NULL); 113 } 114 status_file_len = desired_size; 115 } 116 status_info->noOfHosts++; 117 } 118 119 /* Initialise the spare slot that has been found/created */ 120 /* Note that we do not msync(), since the caller is presumed to be */ 121 /* about to modify the entry further */ 122 memset(spare_slot, 0, sizeof(HostInfo)); 123 strncpy(spare_slot->hostname, hostname, SM_MAXSTRLEN); 124 return (spare_slot); 125 } 126 127 /* init_file -------------------------------------------------------------- */ 128 /* 129 Purpose: Open file, create if necessary, initialise it. 130 Returns: Nothing - exits on error 131 Notes: Called before process becomes daemon, hence logs to 132 stderr rather than syslog. 133 Opens the file, then mmap()s it for ease of access. 134 Also performs initial clean-up of the file, zeroing 135 monitor list pointers, setting the notifyReqd flag in 136 all hosts that had a monitor list, and incrementing 137 the state number to the next even value. 138 */ 139 140 void init_file(const char *filename) 141 { 142 int new_file = FALSE; 143 char buf[HEADER_LEN]; 144 int i; 145 146 /* try to open existing file - if not present, create one */ 147 status_fd = open(filename, O_RDWR); 148 if ((status_fd < 0) && (errno == ENOENT)) 149 { 150 status_fd = open(filename, O_RDWR | O_CREAT, 0644); 151 new_file = TRUE; 152 } 153 if (status_fd < 0) 154 errx(1, "unable to open status file %s", filename); 155 156 /* File now open. mmap() it, with a generous size to allow for */ 157 /* later growth, where we will extend the file but not re-map it. */ 158 status_info = (FileLayout *) 159 mmap(NULL, 0x10000000, PROT_READ | PROT_WRITE, MAP_SHARED, status_fd, 0); 160 161 if (status_info == (FileLayout *) MAP_FAILED) 162 err(1, "unable to mmap() status file"); 163 164 status_file_len = lseek(status_fd, 0L, SEEK_END); 165 166 /* If the file was not newly created, validate the contents, and if */ 167 /* defective, re-create from scratch. */ 168 if (!new_file) 169 { 170 if ((status_file_len < HEADER_LEN) || (status_file_len 171 < (HEADER_LEN + sizeof(HostInfo) * status_info->noOfHosts)) ) 172 { 173 warnx("status file is corrupt"); 174 new_file = TRUE; 175 } 176 } 177 178 /* Initialisation of a new, empty file. */ 179 if (new_file) 180 { 181 memset(buf, 0, sizeof(buf)); 182 lseek(status_fd, 0L, SEEK_SET); 183 write(status_fd, buf, HEADER_LEN); 184 status_file_len = HEADER_LEN; 185 } 186 else 187 { 188 /* Clean-up of existing file - monitored hosts will have a pointer */ 189 /* to a list of clients, which refers to memory in the previous */ 190 /* incarnation of the program and so are meaningless now. These */ 191 /* pointers are zeroed and the fact that the host was previously */ 192 /* monitored is recorded by setting the notifyReqd flag, which will */ 193 /* in due course cause a SM_NOTIFY to be sent. */ 194 /* Note that if we crash twice in quick succession, some hosts may */ 195 /* already have notifyReqd set, where we didn't manage to notify */ 196 /* them before the second crash occurred. */ 197 for (i = 0; i < status_info->noOfHosts; i++) 198 { 199 HostInfo *this_host = &status_info->hosts[i]; 200 201 if (this_host->monList) 202 { 203 this_host->notifyReqd = TRUE; 204 this_host->monList = NULL; 205 } 206 } 207 /* Select the next higher even number for the state counter */ 208 status_info->ourState = (status_info->ourState + 2) & 0xfffffffe; 209 /*???????******/ status_info->ourState++; 210 } 211 } 212 213 /* notify_one_host --------------------------------------------------------- */ 214 /* 215 Purpose: Perform SM_NOTIFY procedure at specified host 216 Returns: TRUE if success, FALSE if failed. 217 */ 218 219 static int notify_one_host(char *hostname) 220 { 221 struct timeval timeout = { 20, 0 }; /* 20 secs timeout */ 222 CLIENT *cli; 223 char dummy; 224 stat_chge arg; 225 char our_hostname[SM_MAXSTRLEN+1]; 226 227 gethostname(our_hostname, sizeof(our_hostname)); 228 our_hostname[SM_MAXSTRLEN] = '\0'; 229 arg.mon_name = our_hostname; 230 arg.state = status_info->ourState; 231 232 if (debug) syslog (LOG_DEBUG, "Sending SM_NOTIFY to host %s from %s", hostname, our_hostname); 233 234 cli = clnt_create(hostname, SM_PROG, SM_VERS, "udp"); 235 if (!cli) 236 { 237 syslog(LOG_ERR, "Failed to contact host %s%s", hostname, 238 clnt_spcreateerror("")); 239 return (FALSE); 240 } 241 242 if (clnt_call(cli, SM_NOTIFY, (xdrproc_t)xdr_stat_chge, &arg, 243 (xdrproc_t)xdr_void, &dummy, timeout) 244 != RPC_SUCCESS) 245 { 246 syslog(LOG_ERR, "Failed to contact rpc.statd at host %s", hostname); 247 clnt_destroy(cli); 248 return (FALSE); 249 } 250 251 clnt_destroy(cli); 252 return (TRUE); 253 } 254 255 /* notify_hosts ------------------------------------------------------------ */ 256 /* 257 Purpose: Send SM_NOTIFY to all hosts marked as requiring it 258 Returns: Nothing, immediately - forks a process to do the work. 259 Notes: Does nothing if there are no monitored hosts. 260 Called after all the initialisation has been done - 261 logs to syslog. 262 */ 263 264 void notify_hosts(void) 265 { 266 int i; 267 int attempts; 268 int work_to_do = FALSE; 269 HostInfo *hp; 270 pid_t pid; 271 272 /* First check if there is in fact any work to do. */ 273 for (i = status_info->noOfHosts, hp = status_info->hosts; i ; i--, hp++) 274 { 275 if (hp->notifyReqd) 276 { 277 work_to_do = TRUE; 278 break; 279 } 280 } 281 282 if (!work_to_do) return; /* No work found */ 283 284 pid = fork(); 285 if (pid == -1) 286 { 287 syslog(LOG_ERR, "Unable to fork notify process - %s", strerror(errno)); 288 return; 289 } 290 if (pid) return; 291 292 /* Here in the child process. We continue until all the hosts marked */ 293 /* as requiring notification have been duly notified. */ 294 /* If one of the initial attempts fails, we sleep for a while and */ 295 /* have another go. This is necessary because when we have crashed, */ 296 /* (eg. a power outage) it is quite possible that we won't be able to */ 297 /* contact all monitored hosts immediately on restart, either because */ 298 /* they crashed too and take longer to come up (in which case the */ 299 /* notification isn't really required), or more importantly if some */ 300 /* router etc. needed to reach the monitored host has not come back */ 301 /* up yet. In this case, we will be a bit late in re-establishing */ 302 /* locks (after the grace period) but that is the best we can do. */ 303 /* We try 10 times at 5 sec intervals, 10 more times at 1 minute */ 304 /* intervals, then 24 more times at hourly intervals, finally */ 305 /* giving up altogether if the host hasn't come back to life after */ 306 /* 24 hours. */ 307 308 for (attempts = 0; attempts < 44; attempts++) 309 { 310 work_to_do = FALSE; /* Unless anything fails */ 311 for (i = status_info->noOfHosts, hp = status_info->hosts; i ; i--, hp++) 312 { 313 if (hp->notifyReqd) 314 { 315 if (notify_one_host(hp->hostname)) 316 { 317 hp->notifyReqd = FALSE; 318 sync_file(); 319 } 320 else work_to_do = TRUE; 321 } 322 } 323 if (!work_to_do) break; 324 if (attempts < 10) sleep(5); 325 else if (attempts < 20) sleep(60); 326 else sleep(60*60); 327 } 328 exit(0); 329 } 330 331 332