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 <netdb.h> 40 #include <stdio.h> 41 #include <string.h> 42 #include <unistd.h> 43 #include <sys/types.h> 44 #include <sys/mman.h> /* For mmap() */ 45 #include <rpc/rpc.h> 46 #include <syslog.h> 47 #include <stdlib.h> 48 49 #include "statd.h" 50 51 FileLayout *status_info; /* Pointer to the mmap()ed status file */ 52 static int status_fd; /* File descriptor for the open file */ 53 static off_t status_file_len; /* Current on-disc length of file */ 54 55 /* sync_file --------------------------------------------------------------- */ 56 /* 57 Purpose: Packaged call of msync() to flush changes to mmap()ed file 58 Returns: Nothing. Errors to syslog. 59 */ 60 61 void sync_file(void) 62 { 63 if (msync((void *)status_info, 0, 0) < 0) 64 { 65 syslog(LOG_ERR, "msync() failed: %s", strerror(errno)); 66 } 67 } 68 69 /* find_host -------------------------------------------------------------- */ 70 /* 71 Purpose: Find the entry in the status file for a given host 72 Returns: Pointer to that entry in the mmap() region, or NULL. 73 Notes: Also creates entries if requested. 74 Failure to create also returns NULL. 75 */ 76 77 HostInfo *find_host(char *hostname, int create) 78 { 79 HostInfo *hp; 80 HostInfo *spare_slot = NULL; 81 HostInfo *result = NULL; 82 struct addrinfo *ai1, *ai2; 83 int i; 84 85 ai2 = NULL; 86 if (getaddrinfo(hostname, NULL, NULL, &ai1) != 0) 87 ai1 = NULL; 88 for (i = 0, hp = status_info->hosts; i < status_info->noOfHosts; i++, hp++) 89 { 90 if (!strncasecmp(hostname, hp->hostname, SM_MAXSTRLEN)) 91 { 92 result = hp; 93 break; 94 } 95 if (hp->hostname[0] != '\0' && 96 getaddrinfo(hp->hostname, NULL, NULL, &ai2) != 0) 97 ai2 = NULL; 98 if (ai1 && ai2) 99 { 100 struct addrinfo *p1, *p2; 101 for (p1 = ai1; !result && p1; p1 = p1->ai_next) 102 { 103 for (p2 = ai2; !result && p2; p2 = p2->ai_next) 104 { 105 if (p1->ai_family == p2->ai_family 106 && p1->ai_addrlen == p2->ai_addrlen 107 && !memcmp(p1->ai_addr, p2->ai_addr, p1->ai_addrlen)) 108 { 109 result = hp; 110 break; 111 } 112 } 113 } 114 if (result) 115 break; 116 } 117 if (ai2) { 118 freeaddrinfo(ai2); 119 ai2 = NULL; 120 } 121 if (!spare_slot && !hp->monList && !hp->notifyReqd) 122 spare_slot = hp; 123 } 124 if (ai1) 125 freeaddrinfo(ai1); 126 127 /* Return if entry found, or if not asked to create one. */ 128 if (result || !create) return (result); 129 130 /* Now create an entry, using the spare slot if one was found or */ 131 /* adding to the end of the list otherwise, extending file if reqd */ 132 if (!spare_slot) 133 { 134 off_t desired_size; 135 spare_slot = &status_info->hosts[status_info->noOfHosts]; 136 desired_size = ((char*)spare_slot - (char*)status_info) + sizeof(HostInfo); 137 if (desired_size > status_file_len) 138 { 139 /* Extend file by writing 1 byte of junk at the desired end pos */ 140 if (lseek(status_fd, desired_size - 1, SEEK_SET) == -1 || 141 write(status_fd, "\0", 1) < 0) 142 { 143 syslog(LOG_ERR, "Unable to extend status file"); 144 return (NULL); 145 } 146 status_file_len = desired_size; 147 } 148 status_info->noOfHosts++; 149 } 150 151 /* Initialise the spare slot that has been found/created */ 152 /* Note that we do not msync(), since the caller is presumed to be */ 153 /* about to modify the entry further */ 154 memset(spare_slot, 0, sizeof(HostInfo)); 155 strncpy(spare_slot->hostname, hostname, SM_MAXSTRLEN); 156 return (spare_slot); 157 } 158 159 /* init_file -------------------------------------------------------------- */ 160 /* 161 Purpose: Open file, create if necessary, initialise it. 162 Returns: Nothing - exits on error 163 Notes: Called before process becomes daemon, hence logs to 164 stderr rather than syslog. 165 Opens the file, then mmap()s it for ease of access. 166 Also performs initial clean-up of the file, zeroing 167 monitor list pointers, setting the notifyReqd flag in 168 all hosts that had a monitor list, and incrementing 169 the state number to the next even value. 170 */ 171 172 void init_file(const char *filename) 173 { 174 int new_file = FALSE; 175 char buf[HEADER_LEN]; 176 int i; 177 178 /* try to open existing file - if not present, create one */ 179 status_fd = open(filename, O_RDWR); 180 if ((status_fd < 0) && (errno == ENOENT)) 181 { 182 status_fd = open(filename, O_RDWR | O_CREAT, 0644); 183 new_file = TRUE; 184 } 185 if (status_fd < 0) 186 errx(1, "unable to open status file %s", filename); 187 188 /* File now open. mmap() it, with a generous size to allow for */ 189 /* later growth, where we will extend the file but not re-map it. */ 190 status_info = (FileLayout *) 191 mmap(NULL, 0x10000000, PROT_READ | PROT_WRITE, MAP_SHARED, status_fd, 0); 192 193 if (status_info == (FileLayout *) MAP_FAILED) 194 err(1, "unable to mmap() status file"); 195 196 status_file_len = lseek(status_fd, 0L, SEEK_END); 197 198 /* If the file was not newly created, validate the contents, and if */ 199 /* defective, re-create from scratch. */ 200 if (!new_file) 201 { 202 if ((status_file_len < HEADER_LEN) || (status_file_len 203 < (HEADER_LEN + sizeof(HostInfo) * status_info->noOfHosts)) ) 204 { 205 warnx("status file is corrupt"); 206 new_file = TRUE; 207 } 208 } 209 210 /* Initialisation of a new, empty file. */ 211 if (new_file) 212 { 213 memset(buf, 0, sizeof(buf)); 214 lseek(status_fd, 0L, SEEK_SET); 215 write(status_fd, buf, HEADER_LEN); 216 status_file_len = HEADER_LEN; 217 } 218 else 219 { 220 /* Clean-up of existing file - monitored hosts will have a pointer */ 221 /* to a list of clients, which refers to memory in the previous */ 222 /* incarnation of the program and so are meaningless now. These */ 223 /* pointers are zeroed and the fact that the host was previously */ 224 /* monitored is recorded by setting the notifyReqd flag, which will */ 225 /* in due course cause a SM_NOTIFY to be sent. */ 226 /* Note that if we crash twice in quick succession, some hosts may */ 227 /* already have notifyReqd set, where we didn't manage to notify */ 228 /* them before the second crash occurred. */ 229 for (i = 0; i < status_info->noOfHosts; i++) 230 { 231 HostInfo *this_host = &status_info->hosts[i]; 232 233 if (this_host->monList) 234 { 235 this_host->notifyReqd = TRUE; 236 this_host->monList = NULL; 237 } 238 } 239 /* Select the next higher even number for the state counter */ 240 status_info->ourState = (status_info->ourState + 2) & 0xfffffffe; 241 /*???????******/ status_info->ourState++; 242 } 243 } 244 245 /* notify_one_host --------------------------------------------------------- */ 246 /* 247 Purpose: Perform SM_NOTIFY procedure at specified host 248 Returns: TRUE if success, FALSE if failed. 249 */ 250 251 static int notify_one_host(char *hostname) 252 { 253 struct timeval timeout = { 20, 0 }; /* 20 secs timeout */ 254 CLIENT *cli; 255 char dummy; 256 stat_chge arg; 257 char our_hostname[SM_MAXSTRLEN+1]; 258 259 gethostname(our_hostname, sizeof(our_hostname)); 260 our_hostname[SM_MAXSTRLEN] = '\0'; 261 arg.mon_name = our_hostname; 262 arg.state = status_info->ourState; 263 264 if (debug) syslog (LOG_DEBUG, "Sending SM_NOTIFY to host %s from %s", hostname, our_hostname); 265 266 cli = clnt_create(hostname, SM_PROG, SM_VERS, "udp"); 267 if (!cli) 268 { 269 syslog(LOG_ERR, "Failed to contact host %s%s", hostname, 270 clnt_spcreateerror("")); 271 return (FALSE); 272 } 273 274 if (clnt_call(cli, SM_NOTIFY, (xdrproc_t)xdr_stat_chge, &arg, 275 (xdrproc_t)xdr_void, &dummy, timeout) 276 != RPC_SUCCESS) 277 { 278 syslog(LOG_ERR, "Failed to contact rpc.statd at host %s", hostname); 279 clnt_destroy(cli); 280 return (FALSE); 281 } 282 283 clnt_destroy(cli); 284 return (TRUE); 285 } 286 287 /* notify_hosts ------------------------------------------------------------ */ 288 /* 289 Purpose: Send SM_NOTIFY to all hosts marked as requiring it 290 Returns: Nothing, immediately - forks a process to do the work. 291 Notes: Does nothing if there are no monitored hosts. 292 Called after all the initialisation has been done - 293 logs to syslog. 294 */ 295 296 void notify_hosts(void) 297 { 298 int i; 299 int attempts; 300 int work_to_do = FALSE; 301 HostInfo *hp; 302 pid_t pid; 303 304 /* First check if there is in fact any work to do. */ 305 for (i = status_info->noOfHosts, hp = status_info->hosts; i ; i--, hp++) 306 { 307 if (hp->notifyReqd) 308 { 309 work_to_do = TRUE; 310 break; 311 } 312 } 313 314 if (!work_to_do) return; /* No work found */ 315 316 pid = fork(); 317 if (pid == -1) 318 { 319 syslog(LOG_ERR, "Unable to fork notify process - %s", strerror(errno)); 320 return; 321 } 322 if (pid) return; 323 324 /* Here in the child process. We continue until all the hosts marked */ 325 /* as requiring notification have been duly notified. */ 326 /* If one of the initial attempts fails, we sleep for a while and */ 327 /* have another go. This is necessary because when we have crashed, */ 328 /* (eg. a power outage) it is quite possible that we won't be able to */ 329 /* contact all monitored hosts immediately on restart, either because */ 330 /* they crashed too and take longer to come up (in which case the */ 331 /* notification isn't really required), or more importantly if some */ 332 /* router etc. needed to reach the monitored host has not come back */ 333 /* up yet. In this case, we will be a bit late in re-establishing */ 334 /* locks (after the grace period) but that is the best we can do. */ 335 /* We try 10 times at 5 sec intervals, 10 more times at 1 minute */ 336 /* intervals, then 24 more times at hourly intervals, finally */ 337 /* giving up altogether if the host hasn't come back to life after */ 338 /* 24 hours. */ 339 340 for (attempts = 0; attempts < 44; attempts++) 341 { 342 work_to_do = FALSE; /* Unless anything fails */ 343 for (i = status_info->noOfHosts, hp = status_info->hosts; i ; i--, hp++) 344 { 345 if (hp->notifyReqd) 346 { 347 if (notify_one_host(hp->hostname)) 348 { 349 hp->notifyReqd = FALSE; 350 sync_file(); 351 } 352 else work_to_do = TRUE; 353 } 354 } 355 if (!work_to_do) break; 356 if (attempts < 10) sleep(5); 357 else if (attempts < 20) sleep(60); 358 else sleep(60*60); 359 } 360 exit(0); 361 } 362 363 364