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 1.2 2005/11/25 00:32:49 swildner Exp $ 33 */ 34 35 #include <err.h> 36 #include <errno.h> 37 #include <fcntl.h> 38 #include <stdio.h> 39 #include <string.h> 40 #include <unistd.h> 41 #include <sys/types.h> 42 #include <sys/mman.h> /* For mmap() */ 43 #include <rpc/rpc.h> 44 #include <syslog.h> 45 46 #include "statd.h" 47 48 FileLayout *status_info; /* Pointer to the mmap()ed status file */ 49 static int status_fd; /* File descriptor for the open file */ 50 static off_t status_file_len; /* Current on-disc length of file */ 51 52 /* sync_file --------------------------------------------------------------- */ 53 /* 54 Purpose: Packaged call of msync() to flush changes to mmap()ed file 55 Returns: Nothing. Errors to syslog. 56 */ 57 58 void 59 sync_file(void) 60 { 61 if (msync((void *)status_info, 0, 0) < 0) 62 { 63 syslog(LOG_ERR, "msync() failed: %s", strerror(errno)); 64 } 65 } 66 67 /* find_host -------------------------------------------------------------- */ 68 /* 69 Purpose: Find the entry in the status file for a given host 70 Returns: Pointer to that entry in the mmap() region, or NULL. 71 Notes: Also creates entries if requested. 72 Failure to create also returns NULL. 73 */ 74 75 HostInfo * 76 find_host(char *hostname, int create) 77 { 78 HostInfo *hp; 79 HostInfo *spare_slot = NULL; 80 HostInfo *result = NULL; 81 int i; 82 83 for (i = 0, hp = status_info->hosts; i < status_info->noOfHosts; i++, hp++) 84 { 85 if (!strncasecmp(hostname, hp->hostname, SM_MAXSTRLEN)) 86 { 87 result = hp; 88 break; 89 } 90 if (!spare_slot && !hp->monList && !hp->notifyReqd) 91 spare_slot = hp; 92 } 93 94 /* Return if entry found, or if not asked to create one. */ 95 if (result || !create) return (result); 96 97 /* Now create an entry, using the spare slot if one was found or */ 98 /* adding to the end of the list otherwise, extending file if reqd */ 99 if (!spare_slot) 100 { 101 off_t desired_size; 102 spare_slot = &status_info->hosts[status_info->noOfHosts]; 103 desired_size = ((char*)spare_slot - (char*)status_info) + sizeof(HostInfo); 104 if (desired_size > status_file_len) 105 { 106 /* Extend file by writing 1 byte of junk at the desired end pos */ 107 lseek(status_fd, desired_size - 1, SEEK_SET); 108 i = write(status_fd, &i, 1); 109 if (i < 1) 110 { 111 syslog(LOG_ERR, "Unable to extend status file"); 112 return (NULL); 113 } 114 status_file_len = desired_size; 115 } 116 status_info->noOfHosts++; 117 } 118 119 /* Initialise the spare slot that has been found/created */ 120 /* Note that we do not msync(), since the caller is presumed to be */ 121 /* about to modify the entry further */ 122 memset(spare_slot, 0, sizeof(HostInfo)); 123 strncpy(spare_slot->hostname, hostname, SM_MAXSTRLEN); 124 return (spare_slot); 125 } 126 127 /* init_file -------------------------------------------------------------- */ 128 /* 129 Purpose: Open file, create if necessary, initialise it. 130 Returns: Nothing - exits on error 131 Notes: Called before process becomes daemon, hence logs to 132 stderr rather than syslog. 133 Opens the file, then mmap()s it for ease of access. 134 Also performs initial clean-up of the file, zeroing 135 monitor list pointers, setting the notifyReqd flag in 136 all hosts that had a monitor list, and incrementing 137 the state number to the next even value. 138 */ 139 140 void 141 init_file(char *filename) 142 { 143 int new_file = FALSE; 144 char buf[HEADER_LEN]; 145 int i; 146 147 /* try to open existing file - if not present, create one */ 148 status_fd = open(filename, O_RDWR); 149 if ((status_fd < 0) && (errno == ENOENT)) 150 { 151 status_fd = open(filename, O_RDWR | O_CREAT, 0644); 152 new_file = TRUE; 153 } 154 if (status_fd < 0) 155 errx(1, "unable to open status file %s", filename); 156 157 /* File now open. mmap() it, with a generous size to allow for */ 158 /* later growth, where we will extend the file but not re-map it. */ 159 status_info = (FileLayout *) 160 mmap(NULL, 0x10000000, PROT_READ | PROT_WRITE, MAP_SHARED, status_fd, 0); 161 162 if (status_info == (FileLayout *) MAP_FAILED) 163 warn("unable to mmap() status file"); 164 165 status_file_len = lseek(status_fd, 0L, SEEK_END); 166 167 /* If the file was not newly created, validate the contents, and if */ 168 /* defective, re-create from scratch. */ 169 if (!new_file) 170 { 171 if ((status_file_len < HEADER_LEN) || (status_file_len 172 < (HEADER_LEN + sizeof(HostInfo) * status_info->noOfHosts)) ) 173 { 174 warnx("status file is corrupt"); 175 new_file = TRUE; 176 } 177 } 178 179 /* Initialisation of a new, empty file. */ 180 if (new_file) 181 { 182 memset(buf, 0, sizeof(buf)); 183 lseek(status_fd, 0L, SEEK_SET); 184 write(status_fd, buf, HEADER_LEN); 185 status_file_len = HEADER_LEN; 186 } 187 else 188 { 189 /* Clean-up of existing file - monitored hosts will have a pointer */ 190 /* to a list of clients, which refers to memory in the previous */ 191 /* incarnation of the program and so are meaningless now. These */ 192 /* pointers are zeroed and the fact that the host was previously */ 193 /* monitored is recorded by setting the notifyReqd flag, which will */ 194 /* in due course cause a SM_NOTIFY to be sent. */ 195 /* Note that if we crash twice in quick succession, some hosts may */ 196 /* already have notifyReqd set, where we didn't manage to notify */ 197 /* them before the second crash occurred. */ 198 for (i = 0; i < status_info->noOfHosts; i++) 199 { 200 HostInfo *this_host = &status_info->hosts[i]; 201 202 if (this_host->monList) 203 { 204 this_host->notifyReqd = TRUE; 205 this_host->monList = NULL; 206 } 207 } 208 /* Select the next higher even number for the state counter */ 209 status_info->ourState = (status_info->ourState + 2) & 0xfffffffe; 210 /*???????******/ status_info->ourState++; 211 } 212 } 213 214 /* xdr_stat_chge ----------------------------------------------------------- */ 215 /* 216 Purpose: XDR-encode structure of type stat_chge 217 Returns: TRUE if successful 218 Notes: This function is missing from librpcsvc, because the 219 sm_inter.x distributed by Sun omits the SM_NOTIFY 220 procedure used between co-operating statd's 221 */ 222 223 bool_t 224 xdr_stat_chge(XDR *xdrs, stat_chge *objp) 225 { 226 if (!xdr_string(xdrs, &objp->mon_name, SM_MAXSTRLEN)) 227 { 228 return (FALSE); 229 } 230 if (!xdr_int(xdrs, &objp->state)) 231 { 232 return (FALSE); 233 } 234 return (TRUE); 235 } 236 237 238 /* notify_one_host --------------------------------------------------------- */ 239 /* 240 Purpose: Perform SM_NOTIFY procedure at specified host 241 Returns: TRUE if success, FALSE if failed. 242 */ 243 244 static int 245 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 290 notify_hosts(void) 291 { 292 int i; 293 int attempts; 294 int work_to_do = FALSE; 295 HostInfo *hp; 296 pid_t pid; 297 298 /* First check if there is in fact any work to do. */ 299 for (i = status_info->noOfHosts, hp = status_info->hosts; i ; i--, hp++) 300 { 301 if (hp->notifyReqd) 302 { 303 work_to_do = TRUE; 304 break; 305 } 306 } 307 308 if (!work_to_do) return; /* No work found */ 309 310 pid = fork(); 311 if (pid == -1) 312 { 313 syslog(LOG_ERR, "Unable to fork notify process - %s", strerror(errno)); 314 return; 315 } 316 if (pid) return; 317 318 /* Here in the child process. We continue until all the hosts marked */ 319 /* as requiring notification have been duly notified. */ 320 /* If one of the initial attempts fails, we sleep for a while and */ 321 /* have another go. This is necessary because when we have crashed, */ 322 /* (eg. a power outage) it is quite possible that we won't be able to */ 323 /* contact all monitored hosts immediately on restart, either because */ 324 /* they crashed too and take longer to come up (in which case the */ 325 /* notification isn't really required), or more importantly if some */ 326 /* router etc. needed to reach the monitored host has not come back */ 327 /* up yet. In this case, we will be a bit late in re-establishing */ 328 /* locks (after the grace period) but that is the best we can do. */ 329 /* We try 10 times at 5 sec intervals, 10 more times at 1 minute */ 330 /* intervals, then 24 more times at hourly intervals, finally */ 331 /* giving up altogether if the host hasn't come back to life after */ 332 /* 24 hours. */ 333 334 for (attempts = 0; attempts < 44; attempts++) 335 { 336 work_to_do = FALSE; /* Unless anything fails */ 337 for (i = status_info->noOfHosts, hp = status_info->hosts; i ; i--, hp++) 338 { 339 if (hp->notifyReqd) 340 { 341 if (notify_one_host(hp->hostname)) 342 { 343 hp->notifyReqd = FALSE; 344 sync_file(); 345 } 346 else work_to_do = TRUE; 347 } 348 } 349 if (!work_to_do) break; 350 if (attempts < 10) sleep(5); 351 else if (attempts < 20) sleep(60); 352 else sleep(60*60); 353 } 354 exit(0); 355 } 356 357 358