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 * $DragonFly: src/usr.sbin/rpc.statd/file.c,v 1.3 2007/11/25 01:28:24 swildner Exp $ 33 */ 34 35 #include <err.h> 36 #include <errno.h> 37 #include <fcntl.h> 38 #include <stdio.h> 39 #include <stdlib.h> 40 #include <string.h> 41 #include <unistd.h> 42 #include <sys/types.h> 43 #include <sys/mman.h> /* For mmap() */ 44 #include <rpc/rpc.h> 45 #include <syslog.h> 46 47 #include "statd.h" 48 49 FileLayout *status_info; /* Pointer to the mmap()ed status file */ 50 static int status_fd; /* File descriptor for the open file */ 51 static off_t status_file_len; /* Current on-disc length of file */ 52 53 /* sync_file --------------------------------------------------------------- */ 54 /* 55 Purpose: Packaged call of msync() to flush changes to mmap()ed file 56 Returns: Nothing. Errors to syslog. 57 */ 58 59 void 60 sync_file(void) 61 { 62 if (msync((void *)status_info, 0, 0) < 0) 63 { 64 syslog(LOG_ERR, "msync() failed: %s", strerror(errno)); 65 } 66 } 67 68 /* find_host -------------------------------------------------------------- */ 69 /* 70 Purpose: Find the entry in the status file for a given host 71 Returns: Pointer to that entry in the mmap() region, or NULL. 72 Notes: Also creates entries if requested. 73 Failure to create also returns NULL. 74 */ 75 76 HostInfo * 77 find_host(char *hostname, int create) 78 { 79 HostInfo *hp; 80 HostInfo *spare_slot = NULL; 81 HostInfo *result = NULL; 82 int i; 83 84 for (i = 0, hp = status_info->hosts; i < status_info->noOfHosts; i++, hp++) 85 { 86 if (!strncasecmp(hostname, hp->hostname, SM_MAXSTRLEN)) 87 { 88 result = hp; 89 break; 90 } 91 if (!spare_slot && !hp->monList && !hp->notifyReqd) 92 spare_slot = hp; 93 } 94 95 /* Return if entry found, or if not asked to create one. */ 96 if (result || !create) return (result); 97 98 /* Now create an entry, using the spare slot if one was found or */ 99 /* adding to the end of the list otherwise, extending file if reqd */ 100 if (!spare_slot) 101 { 102 off_t desired_size; 103 spare_slot = &status_info->hosts[status_info->noOfHosts]; 104 desired_size = ((char*)spare_slot - (char*)status_info) + sizeof(HostInfo); 105 if (desired_size > status_file_len) 106 { 107 /* Extend file by writing 1 byte of junk at the desired end pos */ 108 lseek(status_fd, desired_size - 1, SEEK_SET); 109 i = write(status_fd, &i, 1); 110 if (i < 1) 111 { 112 syslog(LOG_ERR, "Unable to extend status file"); 113 return (NULL); 114 } 115 status_file_len = desired_size; 116 } 117 status_info->noOfHosts++; 118 } 119 120 /* Initialise the spare slot that has been found/created */ 121 /* Note that we do not msync(), since the caller is presumed to be */ 122 /* about to modify the entry further */ 123 memset(spare_slot, 0, sizeof(HostInfo)); 124 strncpy(spare_slot->hostname, hostname, SM_MAXSTRLEN); 125 return (spare_slot); 126 } 127 128 /* init_file -------------------------------------------------------------- */ 129 /* 130 Purpose: Open file, create if necessary, initialise it. 131 Returns: Nothing - exits on error 132 Notes: Called before process becomes daemon, hence logs to 133 stderr rather than syslog. 134 Opens the file, then mmap()s it for ease of access. 135 Also performs initial clean-up of the file, zeroing 136 monitor list pointers, setting the notifyReqd flag in 137 all hosts that had a monitor list, and incrementing 138 the state number to the next even value. 139 */ 140 141 void 142 init_file(char *filename) 143 { 144 int new_file = FALSE; 145 char buf[HEADER_LEN]; 146 int i; 147 148 /* try to open existing file - if not present, create one */ 149 status_fd = open(filename, O_RDWR); 150 if ((status_fd < 0) && (errno == ENOENT)) 151 { 152 status_fd = open(filename, O_RDWR | O_CREAT, 0644); 153 new_file = TRUE; 154 } 155 if (status_fd < 0) 156 errx(1, "unable to open status file %s", filename); 157 158 /* File now open. mmap() it, with a generous size to allow for */ 159 /* later growth, where we will extend the file but not re-map it. */ 160 status_info = (FileLayout *) 161 mmap(NULL, 0x10000000, PROT_READ | PROT_WRITE, MAP_SHARED, status_fd, 0); 162 163 if (status_info == (FileLayout *) MAP_FAILED) 164 warn("unable to mmap() status file"); 165 166 status_file_len = lseek(status_fd, 0L, SEEK_END); 167 168 /* If the file was not newly created, validate the contents, and if */ 169 /* defective, re-create from scratch. */ 170 if (!new_file) 171 { 172 if ((status_file_len < HEADER_LEN) || (status_file_len 173 < (HEADER_LEN + sizeof(HostInfo) * status_info->noOfHosts)) ) 174 { 175 warnx("status file is corrupt"); 176 new_file = TRUE; 177 } 178 } 179 180 /* Initialisation of a new, empty file. */ 181 if (new_file) 182 { 183 memset(buf, 0, sizeof(buf)); 184 lseek(status_fd, 0L, SEEK_SET); 185 write(status_fd, buf, HEADER_LEN); 186 status_file_len = HEADER_LEN; 187 } 188 else 189 { 190 /* Clean-up of existing file - monitored hosts will have a pointer */ 191 /* to a list of clients, which refers to memory in the previous */ 192 /* incarnation of the program and so are meaningless now. These */ 193 /* pointers are zeroed and the fact that the host was previously */ 194 /* monitored is recorded by setting the notifyReqd flag, which will */ 195 /* in due course cause a SM_NOTIFY to be sent. */ 196 /* Note that if we crash twice in quick succession, some hosts may */ 197 /* already have notifyReqd set, where we didn't manage to notify */ 198 /* them before the second crash occurred. */ 199 for (i = 0; i < status_info->noOfHosts; i++) 200 { 201 HostInfo *this_host = &status_info->hosts[i]; 202 203 if (this_host->monList) 204 { 205 this_host->notifyReqd = TRUE; 206 this_host->monList = NULL; 207 } 208 } 209 /* Select the next higher even number for the state counter */ 210 status_info->ourState = (status_info->ourState + 2) & 0xfffffffe; 211 /*???????******/ status_info->ourState++; 212 } 213 } 214 215 /* xdr_stat_chge ----------------------------------------------------------- */ 216 /* 217 Purpose: XDR-encode structure of type stat_chge 218 Returns: TRUE if successful 219 Notes: This function is missing from librpcsvc, because the 220 sm_inter.x distributed by Sun omits the SM_NOTIFY 221 procedure used between co-operating statd's 222 */ 223 224 bool_t 225 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 246 notify_one_host(char *hostname) 247 { 248 struct timeval timeout = { 20, 0 }; /* 20 secs timeout */ 249 CLIENT *cli; 250 char dummy; 251 stat_chge arg; 252 char our_hostname[SM_MAXSTRLEN+1]; 253 254 gethostname(our_hostname, sizeof(our_hostname)); 255 our_hostname[SM_MAXSTRLEN] = '\0'; 256 arg.mon_name = our_hostname; 257 arg.state = status_info->ourState; 258 259 if (debug) syslog (LOG_DEBUG, "Sending SM_NOTIFY to host %s from %s", hostname, our_hostname); 260 261 cli = clnt_create(hostname, SM_PROG, SM_VERS, "udp"); 262 if (!cli) 263 { 264 syslog(LOG_ERR, "Failed to contact host %s%s", hostname, 265 clnt_spcreateerror("")); 266 return (FALSE); 267 } 268 269 if (clnt_call(cli, SM_NOTIFY, xdr_stat_chge, &arg, xdr_void, &dummy, timeout) 270 != RPC_SUCCESS) 271 { 272 syslog(LOG_ERR, "Failed to contact rpc.statd at host %s", hostname); 273 clnt_destroy(cli); 274 return (FALSE); 275 } 276 277 clnt_destroy(cli); 278 return (TRUE); 279 } 280 281 /* notify_hosts ------------------------------------------------------------ */ 282 /* 283 Purpose: Send SM_NOTIFY to all hosts marked as requiring it 284 Returns: Nothing, immediately - forks a process to do the work. 285 Notes: Does nothing if there are no monitored hosts. 286 Called after all the initialisation has been done - 287 logs to syslog. 288 */ 289 290 void 291 notify_hosts(void) 292 { 293 int i; 294 int attempts; 295 int work_to_do = FALSE; 296 HostInfo *hp; 297 pid_t pid; 298 299 /* First check if there is in fact any work to do. */ 300 for (i = status_info->noOfHosts, hp = status_info->hosts; i ; i--, hp++) 301 { 302 if (hp->notifyReqd) 303 { 304 work_to_do = TRUE; 305 break; 306 } 307 } 308 309 if (!work_to_do) return; /* No work found */ 310 311 pid = fork(); 312 if (pid == -1) 313 { 314 syslog(LOG_ERR, "Unable to fork notify process - %s", strerror(errno)); 315 return; 316 } 317 if (pid) return; 318 319 /* Here in the child process. We continue until all the hosts marked */ 320 /* as requiring notification have been duly notified. */ 321 /* If one of the initial attempts fails, we sleep for a while and */ 322 /* have another go. This is necessary because when we have crashed, */ 323 /* (eg. a power outage) it is quite possible that we won't be able to */ 324 /* contact all monitored hosts immediately on restart, either because */ 325 /* they crashed too and take longer to come up (in which case the */ 326 /* notification isn't really required), or more importantly if some */ 327 /* router etc. needed to reach the monitored host has not come back */ 328 /* up yet. In this case, we will be a bit late in re-establishing */ 329 /* locks (after the grace period) but that is the best we can do. */ 330 /* We try 10 times at 5 sec intervals, 10 more times at 1 minute */ 331 /* intervals, then 24 more times at hourly intervals, finally */ 332 /* giving up altogether if the host hasn't come back to life after */ 333 /* 24 hours. */ 334 335 for (attempts = 0; attempts < 44; attempts++) 336 { 337 work_to_do = FALSE; /* Unless anything fails */ 338 for (i = status_info->noOfHosts, hp = status_info->hosts; i ; i--, hp++) 339 { 340 if (hp->notifyReqd) 341 { 342 if (notify_one_host(hp->hostname)) 343 { 344 hp->notifyReqd = FALSE; 345 sync_file(); 346 } 347 else work_to_do = TRUE; 348 } 349 } 350 if (!work_to_do) break; 351 if (attempts < 10) sleep(5); 352 else if (attempts < 20) sleep(60); 353 else sleep(60*60); 354 } 355 exit(0); 356 } 357 358 359