1 /* $NetBSD: statd.c,v 1.7 1997/10/18 14:11:43 drochner 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 #include <sys/cdefs.h> 37 #ifndef lint 38 __RCSID("$NetBSD: statd.c,v 1.7 1997/10/18 14:11:43 drochner Exp $"); 39 #endif 40 41 42 /* main() function for status monitor daemon. Some of the code in this */ 43 /* file was generated by running rpcgen /usr/include/rpcsvc/sm_inter.x */ 44 /* The actual program logic is in the file procs.c */ 45 46 #include <sys/types.h> 47 #include <sys/mman.h> 48 #include <sys/wait.h> 49 50 #include <err.h> 51 #include <errno.h> 52 #include <fcntl.h> 53 #include <signal.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <string.h> 57 #include <syslog.h> 58 #include <unistd.h> 59 60 #include <rpc/rpc.h> 61 62 #include "statd.h" 63 64 int debug = 0; /* Controls syslog() for debug msgs */ 65 int _rpcsvcdirty = 0; /* XXX ??? */ 66 FileLayout *status_info; /* Pointer to mmap()ed status file */ 67 static int status_fd; /* File descriptor for the open file */ 68 static off_t status_file_len; /* Current on-disc length of file */ 69 70 int main __P((int, char **)); 71 static void handle_sigchld __P((int)); 72 static int notify_one_host __P((char *)); 73 extern void sm_prog_1 __P((struct svc_req *, SVCXPRT *)); 74 75 int 76 main(argc, argv) 77 int argc; 78 char **argv; 79 { 80 SVCXPRT *transp; 81 struct sigaction sa; 82 int ch; 83 84 while ((ch = getopt(argc, argv, "d")) != (-1)) { 85 switch (ch) { 86 case 'd': 87 debug = 1; 88 break; 89 default: 90 case '?': 91 errx(1, "usage: rpc.statd [-d]"); 92 /* NOTREACHED */ 93 } 94 } 95 (void)pmap_unset(SM_PROG, SM_VERS); 96 97 transp = svcudp_create(RPC_ANYSOCK); 98 if (transp == NULL) { 99 errx(1, "cannot create udp service."); 100 /* NOTREACHED */ 101 } 102 if (!svc_register(transp, SM_PROG, SM_VERS, sm_prog_1, IPPROTO_UDP)) { 103 errx(1, "unable to register (SM_PROG, SM_VERS, udp)."); 104 /* NOTREACHED */ 105 } 106 transp = svctcp_create(RPC_ANYSOCK, 0, 0); 107 if (transp == NULL) { 108 errx(1, "cannot create tcp service."); 109 /* NOTREACHED */ 110 } 111 if (!svc_register(transp, SM_PROG, SM_VERS, sm_prog_1, IPPROTO_TCP)) { 112 errx(1, "unable to register (SM_PROG, SM_VERS, tcp)."); 113 /* NOTREACHED */ 114 } 115 init_file("/var/db/statd.status"); 116 117 /* 118 * Note that it is NOT sensible to run this program from inetd - the 119 * protocol assumes that it will run immediately at boot time. 120 */ 121 daemon(0, 0); 122 openlog("rpc.statd", 0, LOG_DAEMON); 123 if (debug) 124 syslog(LOG_INFO, "Starting - debug enabled"); 125 else 126 syslog(LOG_INFO, "Starting"); 127 128 /* Install signal handler to collect exit status of child processes */ 129 sa.sa_handler = handle_sigchld; 130 sigemptyset(&sa.sa_mask); 131 sigaddset(&sa.sa_mask, SIGCHLD); 132 sa.sa_flags = SA_RESTART; 133 sigaction(SIGCHLD, &sa, NULL); 134 135 /* Initialisation now complete - start operating */ 136 137 /* 138 * notify_hosts() forks a process (if necessary) to do the 139 * SM_NOTIFY calls, which may be slow. 140 */ 141 notify_hosts(); 142 143 svc_run(); /* Should never return */ 144 exit(1); 145 } 146 147 /* handle_sigchld ---------------------------------------------------------- */ 148 /* 149 * Purpose: Catch SIGCHLD and collect process status 150 * Returns: Nothing. 151 * Notes: No special action required, other than to collect the 152 * process status and hence allow the child to die: 153 * we only use child processes for asynchronous transmission 154 * of SM_NOTIFY to other systems, so it is normal for the 155 * children to exit when they have done their work. 156 */ 157 static void 158 handle_sigchld(sig) 159 int sig; 160 { 161 int pid, status; 162 pid = wait4(-1, &status, WNOHANG, (struct rusage *) 0); 163 if (!pid) 164 syslog(LOG_ERR, "Phantom SIGCHLD??"); 165 else if (status) 166 syslog(LOG_ERR, "Child %d failed with status %d", pid, 167 WEXITSTATUS(status)); 168 else if (debug) 169 syslog(LOG_DEBUG, "Child %d exited OK", pid); 170 } 171 172 /* sync_file --------------------------------------------------------------- */ 173 /* 174 * Purpose: Packaged call of msync() to flush changes to mmap()ed file 175 * Returns: Nothing. Errors to syslog. 176 */ 177 void 178 sync_file() 179 { 180 if (msync((caddr_t)status_info, 0, 0) < 0) 181 syslog(LOG_ERR, "msync() failed: %s", strerror(errno)); 182 } 183 184 /* find_host -------------------------------------------------------------- */ 185 /* 186 * Purpose: Find the entry in the status file for a given host 187 * Returns: Pointer to that entry in the mmap() region, or NULL. 188 * Notes: Also creates entries if requested. 189 * Failure to create also returns NULL. 190 */ 191 HostInfo * 192 find_host(hostname, create) 193 char *hostname; 194 int create; 195 { 196 HostInfo *hp; 197 HostInfo *spare_slot = NULL; 198 HostInfo *result = NULL; 199 int i; 200 201 for (i = 0, hp = status_info->hosts; i < status_info->noOfHosts; 202 i++, hp++) { 203 if (!strncasecmp(hostname, hp->hostname, SM_MAXSTRLEN)) { 204 result = hp; 205 break; 206 } 207 if (!spare_slot && !hp->monList && !hp->notifyReqd) 208 spare_slot = hp; 209 } 210 211 /* Return if entry found, or if not asked to create one. */ 212 if (result || !create) 213 return (result); 214 215 /* 216 * Now create an entry, using the spare slot if one was found or 217 * adding to the end of the list otherwise, extending file if req'd 218 */ 219 if (!spare_slot) { 220 off_t desired_size; 221 spare_slot = &status_info->hosts[status_info->noOfHosts]; 222 desired_size = ((char *)spare_slot - (char *)status_info) + 223 sizeof(HostInfo); 224 225 if (desired_size > status_file_len) { 226 /* Extend file by writing 1 byte of junk at the 227 * desired end pos */ 228 lseek(status_fd, desired_size - 1, SEEK_SET); 229 i = write(status_fd, &i, 1); 230 if (i < 1) { 231 syslog(LOG_ERR, "Unable to extend status file"); 232 return (NULL); 233 } 234 status_file_len = desired_size; 235 } 236 status_info->noOfHosts++; 237 } 238 /* 239 * Initialise the spare slot that has been found/created 240 * Note that we do not msync(), since the caller is presumed to be 241 * about to modify the entry further 242 */ 243 memset(spare_slot, 0, sizeof(HostInfo)); 244 strncpy(spare_slot->hostname, hostname, SM_MAXSTRLEN); 245 return (spare_slot); 246 } 247 248 /* init_file -------------------------------------------------------------- */ 249 /* 250 * Purpose: Open file, create if necessary, initialise it. 251 * Returns: Nothing - exits on error 252 * Notes: Called before process becomes daemon, hence logs to 253 * stderr rather than syslog. 254 * Opens the file, then mmap()s it for ease of access. 255 * Also performs initial clean-up of the file, zeroing 256 * monitor list pointers, setting the notifyReqd flag in 257 * all hosts that had a monitor list, and incrementing 258 * the state number to the next even value. 259 */ 260 void 261 init_file(filename) 262 char *filename; 263 { 264 char buf[HEADER_LEN]; 265 int new_file = FALSE; 266 int i; 267 268 /* try to open existing file - if not present, create one */ 269 status_fd = open(filename, O_RDWR); 270 if ((status_fd < 0) && (errno == ENOENT)) { 271 status_fd = open(filename, O_RDWR | O_CREAT, 0644); 272 new_file = TRUE; 273 } 274 if (status_fd < 0) { 275 err(1, "unable to open status file %s", filename); 276 /* NOTREACHED */ 277 } 278 279 /* 280 * File now open. mmap() it, with a generous size to allow for 281 * later growth, where we will extend the file but not re-map it. 282 */ 283 status_info = (FileLayout *)mmap(NULL, 0x10000000, 284 PROT_READ | PROT_WRITE, MAP_SHARED, status_fd, 0); 285 286 if (status_info == (FileLayout *)(-1)) { 287 perror("rpc.statd"); 288 fprintf(stderr, "Unable to mmap() status file\n"); 289 } 290 status_file_len = lseek(status_fd, 0L, SEEK_END); 291 292 /* 293 * If the file was not newly created, validate the contents, and if 294 * defective, re-create from scratch. 295 */ 296 if (!new_file) { 297 if ((status_file_len < HEADER_LEN) || (status_file_len < 298 (HEADER_LEN + sizeof(HostInfo) * status_info->noOfHosts))) { 299 fprintf(stderr, "rpc.statd: status file is corrupt\n"); 300 new_file = TRUE; 301 } 302 } 303 /* Initialisation of a new, empty file. */ 304 if (new_file) { 305 memset(buf, 0, sizeof(buf)); 306 lseek(status_fd, 0L, SEEK_SET); 307 write(status_fd, buf, HEADER_LEN); 308 status_file_len = HEADER_LEN; 309 } else { 310 /* 311 * Clean-up of existing file - monitored hosts will have a 312 * pointer to a list of clients, which refers to memory in 313 * the previous incarnation of the program and so are 314 * meaningless now. These pointers are zeroed and the fact 315 * that the host was previously monitored is recorded by 316 * setting the notifyReqd flag, which will in due course 317 * cause a SM_NOTIFY to be sent. 318 * 319 * Note that if we crash twice in quick succession, some hosts 320 * may already have notifyReqd set, where we didn't manage to 321 * notify them before the second crash occurred. 322 */ 323 for (i = 0; i < status_info->noOfHosts; i++) { 324 HostInfo *this_host = &status_info->hosts[i]; 325 326 if (this_host->monList) { 327 this_host->notifyReqd = TRUE; 328 this_host->monList = NULL; 329 } 330 } 331 /* Select the next higher even number for the state counter */ 332 status_info->ourState = 333 (status_info->ourState + 2) & 0xfffffffe; 334 status_info->ourState++; /* XXX - ??? */ 335 } 336 } 337 338 /* notify_one_host --------------------------------------------------------- */ 339 /* 340 * Purpose: Perform SM_NOTIFY procedure at specified host 341 * Returns: TRUE if success, FALSE if failed. 342 */ 343 static int 344 notify_one_host(hostname) 345 char *hostname; 346 { 347 struct timeval timeout = {20, 0}; /* 20 secs timeout */ 348 CLIENT *cli; 349 char dummy; 350 stat_chge arg; 351 char our_hostname[SM_MAXSTRLEN + 1]; 352 353 gethostname(our_hostname, sizeof(our_hostname)); 354 our_hostname[SM_MAXSTRLEN] = '\0'; 355 arg.mon_name = our_hostname; 356 arg.state = status_info->ourState; 357 358 if (debug) 359 syslog(LOG_DEBUG, "Sending SM_NOTIFY to host %s from %s", 360 hostname, our_hostname); 361 362 cli = clnt_create(hostname, SM_PROG, SM_VERS, "udp"); 363 if (!cli) { 364 syslog(LOG_ERR, "Failed to contact host %s%s", hostname, 365 clnt_spcreateerror("")); 366 return (FALSE); 367 } 368 if (clnt_call(cli, SM_NOTIFY, xdr_stat_chge, &arg, xdr_void, 369 &dummy, timeout) != RPC_SUCCESS) { 370 syslog(LOG_ERR, "Failed to contact rpc.statd at host %s", 371 hostname); 372 clnt_destroy(cli); 373 return (FALSE); 374 } 375 clnt_destroy(cli); 376 return (TRUE); 377 } 378 379 /* notify_hosts ------------------------------------------------------------ */ 380 /* 381 * Purpose: Send SM_NOTIFY to all hosts marked as requiring it 382 * Returns: Nothing, immediately - forks a process to do the work. 383 * Notes: Does nothing if there are no monitored hosts. 384 * Called after all the initialisation has been done - 385 * logs to syslog. 386 */ 387 void 388 notify_hosts(void) 389 { 390 HostInfo *hp; 391 int i, attempts; 392 int work_to_do = FALSE; 393 pid_t pid; 394 395 /* First check if there is in fact any work to do. */ 396 for (i = status_info->noOfHosts, hp = status_info->hosts; i; 397 i--, hp++) { 398 if (hp->notifyReqd) { 399 work_to_do = TRUE; 400 break; 401 } 402 } 403 404 if (!work_to_do) 405 return; /* No work found */ 406 407 pid = fork(); 408 if (pid == -1) { 409 syslog(LOG_ERR, "Unable to fork notify process - %s", 410 strerror(errno)); 411 return; 412 } 413 if (pid) 414 return; 415 416 /* 417 * Here in the child process. We continue until all the hosts marked 418 * as requiring notification have been duly notified. 419 * If one of the initial attempts fails, we sleep for a while and 420 * have another go. This is necessary because when we have crashed, 421 * (eg. a power outage) it is quite possible that we won't be able to 422 * contact all monitored hosts immediately on restart, either because 423 * they crashed too and take longer to come up (in which case the 424 * notification isn't really required), or more importantly if some 425 * router etc. needed to reach the monitored host has not come back 426 * up yet. In this case, we will be a bit late in re-establishing 427 * locks (after the grace period) but that is the best we can do. 428 * We try 10 times at 5 sec intervals, 10 more times at 1 minute 429 * intervals, then 24 more times at hourly intervals, finally 430 * giving up altogether if the host hasn't come back to life after 431 * 24 hours. 432 */ 433 for (attempts = 0; attempts < 44; attempts++) { 434 work_to_do = FALSE; /* Unless anything fails */ 435 for (i = status_info->noOfHosts, hp = status_info->hosts; i > 0; 436 i--, hp++) { 437 if (hp->notifyReqd) { 438 if (notify_one_host(hp->hostname)) { 439 hp->notifyReqd = FALSE; 440 sync_file(); 441 } else 442 work_to_do = TRUE; 443 } 444 } 445 if (!work_to_do) 446 break; 447 if (attempts < 10) 448 sleep(5); 449 else 450 if (attempts < 20) 451 sleep(60); 452 else 453 sleep(60 * 60); 454 } 455 exit(0); 456 } 457