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 */ 33 34 #include <stdio.h> 35 #include <unistd.h> 36 #include <fcntl.h> 37 #include <errno.h> 38 #include <string.h> 39 #include <sys/types.h> 40 #include <sys/mman.h> /* For mmap() */ 41 #include <rpc/rpc.h> 42 #include <syslog.h> 43 44 #include "statd.h" 45 46 FileLayout *status_info; /* Pointer to the mmap()ed status file */ 47 static int status_fd; /* File descriptor for the open file */ 48 static off_t status_file_len; /* Current on-disc length of file */ 49 50 /* sync_file --------------------------------------------------------------- */ 51 /* 52 Purpose: Packaged call of msync() to flush changes to mmap()ed file 53 Returns: Nothing. Errors to syslog. 54 */ 55 56 void sync_file(void) 57 { 58 if (msync((void *)status_info, 0, 0) < 0) 59 { 60 syslog(LOG_ERR, "msync() failed: %s", strerror(errno)); 61 } 62 } 63 64 /* find_host -------------------------------------------------------------- */ 65 /* 66 Purpose: Find the entry in the status file for a given host 67 Returns: Pointer to that entry in the mmap() region, or NULL. 68 Notes: Also creates entries if requested. 69 Failure to create also returns NULL. 70 */ 71 72 HostInfo *find_host(char *hostname, int create) 73 { 74 HostInfo *hp; 75 HostInfo *spare_slot = NULL; 76 HostInfo *result = NULL; 77 int i; 78 79 for (i = 0, hp = status_info->hosts; i < status_info->noOfHosts; i++, hp++) 80 { 81 if (!strncasecmp(hostname, hp->hostname, SM_MAXSTRLEN)) 82 { 83 result = hp; 84 break; 85 } 86 if (!spare_slot && !hp->monList && !hp->notifyReqd) 87 spare_slot = hp; 88 } 89 90 /* Return if entry found, or if not asked to create one. */ 91 if (result || !create) return (result); 92 93 /* Now create an entry, using the spare slot if one was found or */ 94 /* adding to the end of the list otherwise, extending file if reqd */ 95 if (!spare_slot) 96 { 97 off_t desired_size; 98 spare_slot = &status_info->hosts[status_info->noOfHosts]; 99 desired_size = ((char*)spare_slot - (char*)status_info) + sizeof(HostInfo); 100 if (desired_size > status_file_len) 101 { 102 /* Extend file by writing 1 byte of junk at the desired end pos */ 103 lseek(status_fd, desired_size - 1, SEEK_SET); 104 i = write(status_fd, &i, 1); 105 if (i < 1) 106 { 107 syslog(LOG_ERR, "Unable to extend status file"); 108 return (NULL); 109 } 110 status_file_len = desired_size; 111 } 112 status_info->noOfHosts++; 113 } 114 115 /* Initialise the spare slot that has been found/created */ 116 /* Note that we do not msync(), since the caller is presumed to be */ 117 /* about to modify the entry further */ 118 memset(spare_slot, 0, sizeof(HostInfo)); 119 strncpy(spare_slot->hostname, hostname, SM_MAXSTRLEN); 120 return (spare_slot); 121 } 122 123 /* init_file -------------------------------------------------------------- */ 124 /* 125 Purpose: Open file, create if necessary, initialise it. 126 Returns: Nothing - exits on error 127 Notes: Called before process becomes daemon, hence logs to 128 stderr rather than syslog. 129 Opens the file, then mmap()s it for ease of access. 130 Also performs initial clean-up of the file, zeroing 131 monitor list pointers, setting the notifyReqd flag in 132 all hosts that had a monitor list, and incrementing 133 the state number to the next even value. 134 */ 135 136 void init_file(char *filename) 137 { 138 int new_file = FALSE; 139 char buf[HEADER_LEN]; 140 int i; 141 142 /* try to open existing file - if not present, create one */ 143 status_fd = open(filename, O_RDWR); 144 if ((status_fd < 0) && (errno == ENOENT)) 145 { 146 status_fd = open(filename, O_RDWR | O_CREAT, 0644); 147 new_file = TRUE; 148 } 149 if (status_fd < 0) 150 { 151 perror("rpc.statd"); 152 fprintf(stderr, "Unable to open status file %s\n", filename); 153 exit(1); 154 } 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 { 163 perror("rpc.statd"); 164 fprintf(stderr, "Unable to mmap() status file\n"); 165 } 166 167 status_file_len = lseek(status_fd, 0L, SEEK_END); 168 169 /* If the file was not newly created, validate the contents, and if */ 170 /* defective, re-create from scratch. */ 171 if (!new_file) 172 { 173 if ((status_file_len < HEADER_LEN) || (status_file_len 174 < (HEADER_LEN + sizeof(HostInfo) * status_info->noOfHosts)) ) 175 { 176 fprintf(stderr, "rpc.statd: status file is corrupt\n"); 177 new_file = TRUE; 178 } 179 } 180 181 /* Initialisation of a new, empty file. */ 182 if (new_file) 183 { 184 memset(buf, 0, sizeof(buf)); 185 lseek(status_fd, 0L, SEEK_SET); 186 write(status_fd, buf, HEADER_LEN); 187 status_file_len = HEADER_LEN; 188 } 189 else 190 { 191 /* Clean-up of existing file - monitored hosts will have a pointer */ 192 /* to a list of clients, which refers to memory in the previous */ 193 /* incarnation of the program and so are meaningless now. These */ 194 /* pointers are zeroed and the fact that the host was previously */ 195 /* monitored is recorded by setting the notifyReqd flag, which will */ 196 /* in due course cause a SM_NOTIFY to be sent. */ 197 /* Note that if we crash twice in quick succession, some hosts may */ 198 /* already have notifyReqd set, where we didn't manage to notify */ 199 /* them before the second crash occurred. */ 200 for (i = 0; i < status_info->noOfHosts; i++) 201 { 202 HostInfo *this_host = &status_info->hosts[i]; 203 204 if (this_host->monList) 205 { 206 this_host->notifyReqd = TRUE; 207 this_host->monList = NULL; 208 } 209 } 210 /* Select the next higher even number for the state counter */ 211 status_info->ourState = (status_info->ourState + 2) & 0xfffffffe; 212 /*???????******/ status_info->ourState++; 213 } 214 } 215 216 /* xdr_stat_chge ----------------------------------------------------------- */ 217 /* 218 Purpose: XDR-encode structure of type stat_chge 219 Returns: TRUE if successful 220 Notes: This function is missing from librpcsvc, because the 221 sm_inter.x distributed by Sun omits the SM_NOTIFY 222 procedure used between co-operating statd's 223 */ 224 225 bool_t xdr_stat_chge(XDR *xdrs, stat_chge *objp) 226 { 227 if (!xdr_string(xdrs, &objp->mon_name, SM_MAXSTRLEN)) 228 { 229 return (FALSE); 230 } 231 if (!xdr_int(xdrs, &objp->state)) 232 { 233 return (FALSE); 234 } 235 return (TRUE); 236 } 237 238 239 /* notify_one_host --------------------------------------------------------- */ 240 /* 241 Purpose: Perform SM_NOTIFY procedure at specified host 242 Returns: TRUE if success, FALSE if failed. 243 */ 244 245 static int notify_one_host(char *hostname) 246 { 247 struct timeval timeout = { 20, 0 }; /* 20 secs timeout */ 248 CLIENT *cli; 249 char dummy; 250 stat_chge arg; 251 char our_hostname[SM_MAXSTRLEN+1]; 252 253 gethostname(our_hostname, sizeof(our_hostname)); 254 our_hostname[SM_MAXSTRLEN] = '\0'; 255 arg.mon_name = our_hostname; 256 arg.state = status_info->ourState; 257 258 if (debug) syslog (LOG_DEBUG, "Sending SM_NOTIFY to host %s from %s", hostname, our_hostname); 259 260 cli = clnt_create(hostname, SM_PROG, SM_VERS, "udp"); 261 if (!cli) 262 { 263 syslog(LOG_ERR, "Failed to contact host %s%s", hostname, 264 clnt_spcreateerror("")); 265 return (FALSE); 266 } 267 268 if (clnt_call(cli, SM_NOTIFY, xdr_stat_chge, &arg, xdr_void, &dummy, timeout) 269 != RPC_SUCCESS) 270 { 271 syslog(LOG_ERR, "Failed to contact rpc.statd at host %s", hostname); 272 clnt_destroy(cli); 273 return (FALSE); 274 } 275 276 clnt_destroy(cli); 277 return (TRUE); 278 } 279 280 /* notify_hosts ------------------------------------------------------------ */ 281 /* 282 Purpose: Send SM_NOTIFY to all hosts marked as requiring it 283 Returns: Nothing, immediately - forks a process to do the work. 284 Notes: Does nothing if there are no monitored hosts. 285 Called after all the initialisation has been done - 286 logs to syslog. 287 */ 288 289 void notify_hosts(void) 290 { 291 int i; 292 int attempts; 293 int work_to_do = FALSE; 294 HostInfo *hp; 295 pid_t pid; 296 297 /* First check if there is in fact any work to do. */ 298 for (i = status_info->noOfHosts, hp = status_info->hosts; i ; i--, hp++) 299 { 300 if (hp->notifyReqd) 301 { 302 work_to_do = TRUE; 303 break; 304 } 305 } 306 307 if (!work_to_do) return; /* No work found */ 308 309 pid = fork(); 310 if (pid == -1) 311 { 312 syslog(LOG_ERR, "Unable to fork notify process - %s", strerror(errno)); 313 return; 314 } 315 if (pid) return; 316 317 /* Here in the child process. We continue until all the hosts marked */ 318 /* as requiring notification have been duly notified. */ 319 /* If one of the initial attempts fails, we sleep for a while and */ 320 /* have another go. This is necessary because when we have crashed, */ 321 /* (eg. a power outage) it is quite possible that we won't be able to */ 322 /* contact all monitored hosts immediately on restart, either because */ 323 /* they crashed too and take longer to come up (in which case the */ 324 /* notification isn't really required), or more importantly if some */ 325 /* router etc. needed to reach the monitored host has not come back */ 326 /* up yet. In this case, we will be a bit late in re-establishing */ 327 /* locks (after the grace period) but that is the best we can do. */ 328 /* We try 10 times at 5 sec intervals, 10 more times at 1 minute */ 329 /* intervals, then 24 more times at hourly intervals, finally */ 330 /* giving up altogether if the host hasn't come back to life after */ 331 /* 24 hours. */ 332 333 for (attempts = 0; attempts < 44; attempts++) 334 { 335 work_to_do = FALSE; /* Unless anything fails */ 336 for (i = status_info->noOfHosts, hp = status_info->hosts; i ; i--, hp++) 337 { 338 if (hp->notifyReqd) 339 { 340 if (notify_one_host(hp->hostname)) 341 { 342 hp->notifyReqd = FALSE; 343 sync_file(); 344 } 345 else work_to_do = TRUE; 346 } 347 } 348 if (!work_to_do) break; 349 if (attempts < 10) sleep(5); 350 else if (attempts < 20) sleep(60); 351 else sleep(60*60); 352 } 353 exit(0); 354 } 355 356 357