1 /*- 2 * SPDX-License-Identifier: BSD-4-Clause 3 * 4 * Copyright (c) 1995 5 * A.R. Gordon (andrew.gordon@net-tel.co.uk). All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed for the FreeBSD project 18 * 4. Neither the name of the author nor the names of any co-contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY ANDREW GORDON AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * $FreeBSD$ 35 * 36 */ 37 38 #include <err.h> 39 #include <errno.h> 40 #include <fcntl.h> 41 #include <netdb.h> 42 #include <stdio.h> 43 #include <string.h> 44 #include <unistd.h> 45 #include <sys/types.h> 46 #include <sys/mman.h> /* For mmap() */ 47 #include <rpc/rpc.h> 48 #include <syslog.h> 49 #include <stdlib.h> 50 51 #include "statd.h" 52 53 FileLayout *status_info; /* Pointer to the mmap()ed status file */ 54 static int status_fd; /* File descriptor for the open file */ 55 static off_t status_file_len; /* Current on-disc length of file */ 56 57 /* sync_file --------------------------------------------------------------- */ 58 /* 59 Purpose: Packaged call of msync() to flush changes to mmap()ed file 60 Returns: Nothing. Errors to syslog. 61 */ 62 63 void sync_file(void) 64 { 65 if (msync((void *)status_info, 0, 0) < 0) 66 { 67 syslog(LOG_ERR, "msync() failed: %s", strerror(errno)); 68 } 69 } 70 71 /* find_host -------------------------------------------------------------- */ 72 /* 73 Purpose: Find the entry in the status file for a given host 74 Returns: Pointer to that entry in the mmap() region, or NULL. 75 Notes: Also creates entries if requested. 76 Failure to create also returns NULL. 77 */ 78 79 HostInfo *find_host(char *hostname, int create) 80 { 81 HostInfo *hp; 82 HostInfo *spare_slot = NULL; 83 HostInfo *result = NULL; 84 struct addrinfo *ai1, *ai2; 85 int i; 86 87 ai2 = NULL; 88 if (getaddrinfo(hostname, NULL, NULL, &ai1) != 0) 89 ai1 = NULL; 90 for (i = 0, hp = status_info->hosts; i < status_info->noOfHosts; i++, hp++) 91 { 92 if (!strncasecmp(hostname, hp->hostname, SM_MAXSTRLEN)) 93 { 94 result = hp; 95 break; 96 } 97 if (hp->hostname[0] != '\0' && 98 getaddrinfo(hp->hostname, NULL, NULL, &ai2) != 0) 99 ai2 = NULL; 100 if (ai1 && ai2) 101 { 102 struct addrinfo *p1, *p2; 103 for (p1 = ai1; !result && p1; p1 = p1->ai_next) 104 { 105 for (p2 = ai2; !result && p2; p2 = p2->ai_next) 106 { 107 if (p1->ai_family == p2->ai_family 108 && p1->ai_addrlen == p2->ai_addrlen 109 && !memcmp(p1->ai_addr, p2->ai_addr, p1->ai_addrlen)) 110 { 111 result = hp; 112 break; 113 } 114 } 115 } 116 if (result) 117 break; 118 } 119 if (ai2) { 120 freeaddrinfo(ai2); 121 ai2 = NULL; 122 } 123 if (!spare_slot && !hp->monList && !hp->notifyReqd) 124 spare_slot = hp; 125 } 126 if (ai1) 127 freeaddrinfo(ai1); 128 129 /* Return if entry found, or if not asked to create one. */ 130 if (result || !create) return (result); 131 132 /* Now create an entry, using the spare slot if one was found or */ 133 /* adding to the end of the list otherwise, extending file if reqd */ 134 if (!spare_slot) 135 { 136 off_t desired_size; 137 spare_slot = &status_info->hosts[status_info->noOfHosts]; 138 desired_size = ((char*)spare_slot - (char*)status_info) + sizeof(HostInfo); 139 if (desired_size > status_file_len) 140 { 141 /* Extend file by writing 1 byte of junk at the desired end pos */ 142 if (lseek(status_fd, desired_size - 1, SEEK_SET) == -1 || 143 write(status_fd, "\0", 1) < 0) 144 { 145 syslog(LOG_ERR, "Unable to extend status file"); 146 return (NULL); 147 } 148 status_file_len = desired_size; 149 } 150 status_info->noOfHosts++; 151 } 152 153 /* Initialise the spare slot that has been found/created */ 154 /* Note that we do not msync(), since the caller is presumed to be */ 155 /* about to modify the entry further */ 156 memset(spare_slot, 0, sizeof(HostInfo)); 157 strncpy(spare_slot->hostname, hostname, SM_MAXSTRLEN); 158 return (spare_slot); 159 } 160 161 /* init_file -------------------------------------------------------------- */ 162 /* 163 Purpose: Open file, create if necessary, initialise it. 164 Returns: Nothing - exits on error 165 Notes: Called before process becomes daemon, hence logs to 166 stderr rather than syslog. 167 Opens the file, then mmap()s it for ease of access. 168 Also performs initial clean-up of the file, zeroing 169 monitor list pointers, setting the notifyReqd flag in 170 all hosts that had a monitor list, and incrementing 171 the state number to the next even value. 172 */ 173 174 void init_file(const char *filename) 175 { 176 int new_file = FALSE; 177 char buf[HEADER_LEN]; 178 int i; 179 180 /* try to open existing file - if not present, create one */ 181 status_fd = open(filename, O_RDWR); 182 if ((status_fd < 0) && (errno == ENOENT)) 183 { 184 status_fd = open(filename, O_RDWR | O_CREAT, 0644); 185 new_file = TRUE; 186 } 187 if (status_fd < 0) 188 errx(1, "unable to open status file %s", filename); 189 190 /* File now open. mmap() it, with a generous size to allow for */ 191 /* later growth, where we will extend the file but not re-map it. */ 192 status_info = (FileLayout *) 193 mmap(NULL, 0x10000000, PROT_READ | PROT_WRITE, MAP_SHARED, status_fd, 0); 194 195 if (status_info == (FileLayout *) MAP_FAILED) 196 err(1, "unable to mmap() status file"); 197 198 status_file_len = lseek(status_fd, 0L, SEEK_END); 199 200 /* If the file was not newly created, validate the contents, and if */ 201 /* defective, re-create from scratch. */ 202 if (!new_file) 203 { 204 if ((status_file_len < (off_t)HEADER_LEN) || (status_file_len 205 < (off_t)(HEADER_LEN + sizeof(HostInfo) * status_info->noOfHosts)) ) 206 { 207 warnx("status file is corrupt"); 208 new_file = TRUE; 209 } 210 } 211 212 /* Initialisation of a new, empty file. */ 213 if (new_file) 214 { 215 memset(buf, 0, sizeof(buf)); 216 lseek(status_fd, 0L, SEEK_SET); 217 write(status_fd, buf, HEADER_LEN); 218 status_file_len = HEADER_LEN; 219 } 220 else 221 { 222 /* Clean-up of existing file - monitored hosts will have a pointer */ 223 /* to a list of clients, which refers to memory in the previous */ 224 /* incarnation of the program and so are meaningless now. These */ 225 /* pointers are zeroed and the fact that the host was previously */ 226 /* monitored is recorded by setting the notifyReqd flag, which will */ 227 /* in due course cause a SM_NOTIFY to be sent. */ 228 /* Note that if we crash twice in quick succession, some hosts may */ 229 /* already have notifyReqd set, where we didn't manage to notify */ 230 /* them before the second crash occurred. */ 231 for (i = 0; i < status_info->noOfHosts; i++) 232 { 233 HostInfo *this_host = &status_info->hosts[i]; 234 235 if (this_host->monList) 236 { 237 this_host->notifyReqd = TRUE; 238 this_host->monList = NULL; 239 } 240 } 241 /* Select the next higher even number for the state counter */ 242 status_info->ourState = (status_info->ourState + 2) & 0xfffffffe; 243 /*???????******/ status_info->ourState++; 244 } 245 } 246 247 /* notify_one_host --------------------------------------------------------- */ 248 /* 249 Purpose: Perform SM_NOTIFY procedure at specified host 250 Returns: TRUE if success, FALSE if failed. 251 Notes: Only report failure if verbose is non-zero. Caller will 252 only set verbose to non-zero for the first attempt to 253 contact the host. 254 */ 255 256 static int notify_one_host(char *hostname, int verbose) 257 { 258 struct timeval timeout = { 20, 0 }; /* 20 secs timeout */ 259 CLIENT *cli; 260 char dummy; 261 stat_chge arg; 262 char our_hostname[SM_MAXSTRLEN+1]; 263 264 gethostname(our_hostname, sizeof(our_hostname)); 265 our_hostname[SM_MAXSTRLEN] = '\0'; 266 arg.mon_name = our_hostname; 267 arg.state = status_info->ourState; 268 269 if (debug) syslog (LOG_DEBUG, "Sending SM_NOTIFY to host %s from %s", hostname, our_hostname); 270 271 cli = clnt_create(hostname, SM_PROG, SM_VERS, "udp"); 272 if (!cli) 273 { 274 syslog(LOG_ERR, "Failed to contact host %s%s", hostname, 275 clnt_spcreateerror("")); 276 return (FALSE); 277 } 278 279 if (clnt_call(cli, SM_NOTIFY, (xdrproc_t)xdr_stat_chge, &arg, 280 (xdrproc_t)xdr_void, &dummy, timeout) 281 != RPC_SUCCESS) 282 { 283 if (verbose) 284 syslog(LOG_ERR, "Failed to contact rpc.statd at host %s", hostname); 285 clnt_destroy(cli); 286 return (FALSE); 287 } 288 289 clnt_destroy(cli); 290 return (TRUE); 291 } 292 293 /* notify_hosts ------------------------------------------------------------ */ 294 /* 295 Purpose: Send SM_NOTIFY to all hosts marked as requiring it 296 Returns: Nothing, immediately - forks a process to do the work. 297 Notes: Does nothing if there are no monitored hosts. 298 Called after all the initialisation has been done - 299 logs to syslog. 300 */ 301 302 void notify_hosts(void) 303 { 304 int i; 305 int attempts; 306 int work_to_do = FALSE; 307 HostInfo *hp; 308 pid_t pid; 309 310 /* First check if there is in fact any work to do. */ 311 for (i = status_info->noOfHosts, hp = status_info->hosts; i ; i--, hp++) 312 { 313 if (hp->notifyReqd) 314 { 315 work_to_do = TRUE; 316 break; 317 } 318 } 319 320 if (!work_to_do) return; /* No work found */ 321 322 pid = fork(); 323 if (pid == -1) 324 { 325 syslog(LOG_ERR, "Unable to fork notify process - %s", strerror(errno)); 326 return; 327 } 328 if (pid) return; 329 330 /* Here in the child process. We continue until all the hosts marked */ 331 /* as requiring notification have been duly notified. */ 332 /* If one of the initial attempts fails, we sleep for a while and */ 333 /* have another go. This is necessary because when we have crashed, */ 334 /* (eg. a power outage) it is quite possible that we won't be able to */ 335 /* contact all monitored hosts immediately on restart, either because */ 336 /* they crashed too and take longer to come up (in which case the */ 337 /* notification isn't really required), or more importantly if some */ 338 /* router etc. needed to reach the monitored host has not come back */ 339 /* up yet. In this case, we will be a bit late in re-establishing */ 340 /* locks (after the grace period) but that is the best we can do. */ 341 /* We try 10 times at 5 sec intervals, 10 more times at 1 minute */ 342 /* intervals, then 24 more times at hourly intervals, finally */ 343 /* giving up altogether if the host hasn't come back to life after */ 344 /* 24 hours. */ 345 346 for (attempts = 0; attempts < 44; attempts++) 347 { 348 work_to_do = FALSE; /* Unless anything fails */ 349 for (i = status_info->noOfHosts, hp = status_info->hosts; i ; i--, hp++) 350 { 351 if (hp->notifyReqd) 352 { 353 if (notify_one_host(hp->hostname, attempts == 0)) 354 { 355 hp->notifyReqd = FALSE; 356 sync_file(); 357 } 358 else work_to_do = TRUE; 359 } 360 } 361 if (!work_to_do) break; 362 if (attempts < 10) sleep(5); 363 else if (attempts < 20) sleep(60); 364 else sleep(60*60); 365 } 366 exit(0); 367 } 368 369 370