1 /* $NetBSD: statd.c,v 1.1 1997/03/10 06:28:31 scottr Exp $ */ 2 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 */ 35 36 37 /* main() function for status monitor daemon. Some of the code in this */ 38 /* file was generated by running rpcgen /usr/include/rpcsvc/sm_inter.x */ 39 /* The actual program logic is in the file procs.c */ 40 41 #include <stdio.h> 42 #include <errno.h> 43 #include <fcntl.h> 44 #include <signal.h> 45 #include <string.h> 46 #include <syslog.h> 47 #include <unistd.h> 48 #include <sys/types.h> 49 #include <sys/mman.h> 50 #include <sys/wait.h> 51 52 #include <rpc/rpc.h> 53 54 #include "statd.h" 55 56 #ifndef lint 57 static char rcsid[] = "$NetBSD: statd.c,v 1.1 1997/03/10 06:28:31 scottr Exp $"; 58 #endif /* not lint */ 59 60 int debug = 0; /* Controls syslog() for debug msgs */ 61 int _rpcsvcdirty = 0; /* XXX ??? */ 62 FileLayout *status_info; /* Pointer to mmap()ed status file */ 63 static int status_fd; /* File descriptor for the open file */ 64 static off_t status_file_len; /* Current on-disc length of file */ 65 66 extern void sm_prog_1(struct svc_req * rqstp, SVCXPRT * transp); 67 static void handle_sigchld(); 68 69 main(argc, argv) 70 int argc; 71 char **argv; 72 { 73 SVCXPRT *transp; 74 struct sigaction sa; 75 int ch; 76 77 while ((ch = getopt(argc, argv, "d")) != (-1)) { 78 switch (ch) { 79 case 'd': 80 debug = 1; 81 break; 82 default: 83 case '?': 84 errx(1, "usage: rpc.statd [-d]"); 85 /* NOTREACHED */ 86 } 87 } 88 (void)pmap_unset(SM_PROG, SM_VERS); 89 90 transp = svcudp_create(RPC_ANYSOCK); 91 if (transp == NULL) { 92 errx(1, "cannot create udp service."); 93 /* NOTREACHED */ 94 } 95 if (!svc_register(transp, SM_PROG, SM_VERS, sm_prog_1, IPPROTO_UDP)) { 96 errx(1, "unable to register (SM_PROG, SM_VERS, udp)."); 97 /* NOTREACHED */ 98 } 99 transp = svctcp_create(RPC_ANYSOCK, 0, 0); 100 if (transp == NULL) { 101 errx(1, "cannot create tcp service."); 102 /* NOTREACHED */ 103 } 104 if (!svc_register(transp, SM_PROG, SM_VERS, sm_prog_1, IPPROTO_TCP)) { 105 errx(1, "unable to register (SM_PROG, SM_VERS, tcp)."); 106 /* NOTREACHED */ 107 } 108 init_file("/var/db/statd.status"); 109 110 /* 111 * Note that it is NOT sensible to run this program from inetd - the 112 * protocol assumes that it will run immediately at boot time. 113 */ 114 daemon(0, 0); 115 openlog("rpc.statd", 0, LOG_DAEMON); 116 if (debug) 117 syslog(LOG_INFO, "Starting - debug enabled"); 118 else 119 syslog(LOG_INFO, "Starting"); 120 121 /* Install signal handler to collect exit status of child processes */ 122 sa.sa_handler = handle_sigchld; 123 sigemptyset(&sa.sa_mask); 124 sigaddset(&sa.sa_mask, SIGCHLD); 125 sa.sa_flags = SA_RESTART; 126 sigaction(SIGCHLD, &sa, NULL); 127 128 /* Initialisation now complete - start operating */ 129 130 /* 131 * notify_hosts() forks a process (if necessary) to do the 132 * SM_NOTIFY calls, which may be slow. 133 */ 134 notify_hosts(); 135 136 svc_run(); /* Should never return */ 137 exit(1); 138 } 139 140 /* handle_sigchld ---------------------------------------------------------- */ 141 /* 142 * Purpose: Catch SIGCHLD and collect process status 143 * Returns: Nothing. 144 * Notes: No special action required, other than to collect the 145 * process status and hence allow the child to die: 146 * we only use child processes for asynchronous transmission 147 * of SM_NOTIFY to other systems, so it is normal for the 148 * children to exit when they have done their work. 149 */ 150 static void 151 handle_sigchld(sig, code, scp) 152 int sig, code; 153 struct sigcontext *scp; 154 { 155 int pid, status; 156 pid = wait4(-1, &status, WNOHANG, (struct rusage *) 0); 157 if (!pid) 158 syslog(LOG_ERR, "Phantom SIGCHLD??"); 159 else if (status) 160 syslog(LOG_ERR, "Child %d failed with status %d", pid, 161 WEXITSTATUS(status)); 162 else if (debug) 163 syslog(LOG_DEBUG, "Child %d exited OK", pid); 164 } 165 166 /* sync_file --------------------------------------------------------------- */ 167 /* 168 * Purpose: Packaged call of msync() to flush changes to mmap()ed file 169 * Returns: Nothing. Errors to syslog. 170 */ 171 void 172 sync_file() 173 { 174 if (msync((void *)status_info, 0) < 0) 175 syslog(LOG_ERR, "msync() failed: %s", strerror(errno)); 176 } 177 178 /* find_host -------------------------------------------------------------- */ 179 /* 180 * Purpose: Find the entry in the status file for a given host 181 * Returns: Pointer to that entry in the mmap() region, or NULL. 182 * Notes: Also creates entries if requested. 183 * Failure to create also returns NULL. 184 */ 185 HostInfo * 186 find_host(hostname, create) 187 char *hostname; 188 int create; 189 { 190 HostInfo *hp; 191 HostInfo *spare_slot = NULL; 192 HostInfo *result = NULL; 193 int i; 194 195 for (i = 0, hp = status_info->hosts; i < status_info->noOfHosts; 196 i++, hp++) { 197 if (!strncasecmp(hostname, hp->hostname, SM_MAXSTRLEN)) { 198 result = hp; 199 break; 200 } 201 if (!spare_slot && !hp->monList && !hp->notifyReqd) 202 spare_slot = hp; 203 } 204 205 /* Return if entry found, or if not asked to create one. */ 206 if (result || !create) 207 return (result); 208 209 /* 210 * Now create an entry, using the spare slot if one was found or 211 * adding to the end of the list otherwise, extending file if req'd 212 */ 213 if (!spare_slot) { 214 off_t desired_size; 215 spare_slot = &status_info->hosts[status_info->noOfHosts]; 216 desired_size = ((char *)spare_slot - (char *)status_info) + 217 sizeof(HostInfo); 218 219 if (desired_size > status_file_len) { 220 /* Extend file by writing 1 byte of junk at the 221 * desired end pos */ 222 lseek(status_fd, desired_size - 1, SEEK_SET); 223 i = write(status_fd, &i, 1); 224 if (i < 1) { 225 syslog(LOG_ERR, "Unable to extend status file"); 226 return (NULL); 227 } 228 status_file_len = desired_size; 229 } 230 status_info->noOfHosts++; 231 } 232 /* 233 * Initialise the spare slot that has been found/created 234 * Note that we do not msync(), since the caller is presumed to be 235 * about to modify the entry further 236 */ 237 memset(spare_slot, 0, sizeof(HostInfo)); 238 strncpy(spare_slot->hostname, hostname, SM_MAXSTRLEN); 239 return (spare_slot); 240 } 241 242 /* init_file -------------------------------------------------------------- */ 243 /* 244 * Purpose: Open file, create if necessary, initialise it. 245 * Returns: Nothing - exits on error 246 * Notes: Called before process becomes daemon, hence logs to 247 * stderr rather than syslog. 248 * Opens the file, then mmap()s it for ease of access. 249 * Also performs initial clean-up of the file, zeroing 250 * monitor list pointers, setting the notifyReqd flag in 251 * all hosts that had a monitor list, and incrementing 252 * the state number to the next even value. 253 */ 254 void 255 init_file(filename) 256 char *filename; 257 { 258 char buf[HEADER_LEN]; 259 int new_file = FALSE; 260 int i; 261 262 /* try to open existing file - if not present, create one */ 263 status_fd = open(filename, O_RDWR); 264 if ((status_fd < 0) && (errno == ENOENT)) { 265 status_fd = open(filename, O_RDWR | O_CREAT, 0644); 266 new_file = TRUE; 267 } 268 if (status_fd < 0) { 269 err(1, "unable to open status file %s", filename); 270 /* NOTREACHED */ 271 } 272 273 /* 274 * File now open. mmap() it, with a generous size to allow for 275 * later growth, where we will extend the file but not re-map it. 276 */ 277 status_info = (FileLayout *)mmap(NULL, 0x10000000, 278 PROT_READ | PROT_WRITE, MAP_SHARED, status_fd, 0); 279 280 if (status_info == (FileLayout *)(-1)) { 281 perror("rpc.statd"); 282 fprintf(stderr, "Unable to mmap() status file\n"); 283 } 284 status_file_len = lseek(status_fd, 0L, SEEK_END); 285 286 /* 287 * If the file was not newly created, validate the contents, and if 288 * defective, re-create from scratch. 289 */ 290 if (!new_file) { 291 if ((status_file_len < HEADER_LEN) || (status_file_len < 292 (HEADER_LEN + sizeof(HostInfo) * status_info->noOfHosts))) { 293 fprintf(stderr, "rpc.statd: status file is corrupt\n"); 294 new_file = TRUE; 295 } 296 } 297 /* Initialisation of a new, empty file. */ 298 if (new_file) { 299 memset(buf, 0, sizeof(buf)); 300 lseek(status_fd, 0L, SEEK_SET); 301 write(status_fd, buf, HEADER_LEN); 302 status_file_len = HEADER_LEN; 303 } else { 304 /* 305 * Clean-up of existing file - monitored hosts will have a 306 * pointer to a list of clients, which refers to memory in 307 * the previous incarnation of the program and so are 308 * meaningless now. These pointers are zeroed and the fact 309 * that the host was previously monitored is recorded by 310 * setting the notifyReqd flag, which will in due course 311 * cause a SM_NOTIFY to be sent. 312 * 313 * Note that if we crash twice in quick succession, some hosts 314 * may already have notifyReqd set, where we didn't manage to 315 * notify them before the second crash occurred. 316 */ 317 for (i = 0; i < status_info->noOfHosts; i++) { 318 HostInfo *this_host = &status_info->hosts[i]; 319 320 if (this_host->monList) { 321 this_host->notifyReqd = TRUE; 322 this_host->monList = NULL; 323 } 324 } 325 /* Select the next higher even number for the state counter */ 326 status_info->ourState = 327 (status_info->ourState + 2) & 0xfffffffe; 328 status_info->ourState++; /* XXX - ??? */ 329 } 330 } 331 332 /* notify_one_host --------------------------------------------------------- */ 333 /* 334 * Purpose: Perform SM_NOTIFY procedure at specified host 335 * Returns: TRUE if success, FALSE if failed. 336 */ 337 static int 338 notify_one_host(hostname) 339 char *hostname; 340 { 341 struct timeval timeout = {20, 0}; /* 20 secs timeout */ 342 CLIENT *cli; 343 char dummy; 344 stat_chge arg; 345 char our_hostname[SM_MAXSTRLEN + 1]; 346 347 gethostname(our_hostname, sizeof(our_hostname)); 348 our_hostname[SM_MAXSTRLEN] = '\0'; 349 arg.mon_name = our_hostname; 350 arg.state = status_info->ourState; 351 352 if (debug) 353 syslog(LOG_DEBUG, "Sending SM_NOTIFY to host %s from %s", 354 hostname, our_hostname); 355 356 cli = clnt_create(hostname, SM_PROG, SM_VERS, "udp"); 357 if (!cli) { 358 syslog(LOG_ERR, "Failed to contact host %s%s", hostname, 359 clnt_spcreateerror("")); 360 return (FALSE); 361 } 362 if (clnt_call(cli, SM_NOTIFY, xdr_stat_chge, &arg, xdr_void, 363 &dummy, timeout) != RPC_SUCCESS) { 364 syslog(LOG_ERR, "Failed to contact rpc.statd at host %s", 365 hostname); 366 clnt_destroy(cli); 367 return (FALSE); 368 } 369 clnt_destroy(cli); 370 return (TRUE); 371 } 372 373 /* notify_hosts ------------------------------------------------------------ */ 374 /* 375 * Purpose: Send SM_NOTIFY to all hosts marked as requiring it 376 * Returns: Nothing, immediately - forks a process to do the work. 377 * Notes: Does nothing if there are no monitored hosts. 378 * Called after all the initialisation has been done - 379 * logs to syslog. 380 */ 381 void 382 notify_hosts(void) 383 { 384 HostInfo *hp; 385 int i, attempts; 386 int work_to_do = FALSE; 387 pid_t pid; 388 389 /* First check if there is in fact any work to do. */ 390 for (i = status_info->noOfHosts, hp = status_info->hosts; i; 391 i--, hp++) { 392 if (hp->notifyReqd) { 393 work_to_do = TRUE; 394 break; 395 } 396 } 397 398 if (!work_to_do) 399 return; /* No work found */ 400 401 pid = fork(); 402 if (pid == -1) { 403 syslog(LOG_ERR, "Unable to fork notify process - %s", 404 strerror(errno)); 405 return; 406 } 407 if (pid) 408 return; 409 410 /* 411 * Here in the child process. We continue until all the hosts marked 412 * as requiring notification have been duly notified. 413 * If one of the initial attempts fails, we sleep for a while and 414 * have another go. This is necessary because when we have crashed, 415 * (eg. a power outage) it is quite possible that we won't be able to 416 * contact all monitored hosts immediately on restart, either because 417 * they crashed too and take longer to come up (in which case the 418 * notification isn't really required), or more importantly if some 419 * router etc. needed to reach the monitored host has not come back 420 * up yet. In this case, we will be a bit late in re-establishing 421 * locks (after the grace period) but that is the best we can do. 422 * We try 10 times at 5 sec intervals, 10 more times at 1 minute 423 * intervals, then 24 more times at hourly intervals, finally 424 * giving up altogether if the host hasn't come back to life after 425 * 24 hours. 426 */ 427 for (attempts = 0; attempts < 44; attempts++) { 428 work_to_do = FALSE; /* Unless anything fails */ 429 for (i = status_info->noOfHosts, hp = status_info->hosts; i > 0; 430 i--, hp++) { 431 if (hp->notifyReqd) { 432 if (notify_one_host(hp->hostname)) { 433 hp->notifyReqd = FALSE; 434 sync_file(); 435 } else 436 work_to_do = TRUE; 437 } 438 } 439 if (!work_to_do) 440 break; 441 if (attempts < 10) 442 sleep(5); 443 else 444 if (attempts < 20) 445 sleep(60); 446 else 447 sleep(60 * 60); 448 } 449 exit(0); 450 } 451