1 /*-
2 * SPDX-License-Identifier: BSD-4-Clause
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 <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
sync_file(void)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
find_host(char * hostname,int create)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
init_file(const char * filename)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 < (off_t)HEADER_LEN) || (status_file_len
203 < (off_t)(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 Notes: Only report failure if verbose is non-zero. Caller will
250 only set verbose to non-zero for the first attempt to
251 contact the host.
252 */
253
notify_one_host(char * hostname,int verbose)254 static int notify_one_host(char *hostname, int verbose)
255 {
256 struct timeval timeout = { 20, 0 }; /* 20 secs timeout */
257 CLIENT *cli;
258 char dummy;
259 stat_chge arg;
260 char our_hostname[SM_MAXSTRLEN+1];
261
262 gethostname(our_hostname, sizeof(our_hostname));
263 our_hostname[SM_MAXSTRLEN] = '\0';
264 arg.mon_name = our_hostname;
265 arg.state = status_info->ourState;
266
267 if (debug) syslog (LOG_DEBUG, "Sending SM_NOTIFY to host %s from %s", hostname, our_hostname);
268
269 cli = clnt_create(hostname, SM_PROG, SM_VERS, "udp");
270 if (!cli)
271 {
272 syslog(LOG_ERR, "Failed to contact host %s%s", hostname,
273 clnt_spcreateerror(""));
274 return (FALSE);
275 }
276
277 if (clnt_call(cli, SM_NOTIFY, (xdrproc_t)xdr_stat_chge, &arg,
278 (xdrproc_t)xdr_void, &dummy, timeout)
279 != RPC_SUCCESS)
280 {
281 if (verbose)
282 syslog(LOG_ERR, "Failed to contact rpc.statd at host %s", hostname);
283 clnt_destroy(cli);
284 return (FALSE);
285 }
286
287 clnt_destroy(cli);
288 return (TRUE);
289 }
290
291 /* notify_hosts ------------------------------------------------------------ */
292 /*
293 Purpose: Send SM_NOTIFY to all hosts marked as requiring it
294 Returns: Nothing, immediately - forks a process to do the work.
295 Notes: Does nothing if there are no monitored hosts.
296 Called after all the initialisation has been done -
297 logs to syslog.
298 */
299
notify_hosts(void)300 void notify_hosts(void)
301 {
302 int i;
303 int attempts;
304 int work_to_do = FALSE;
305 HostInfo *hp;
306 pid_t pid;
307
308 /* First check if there is in fact any work to do. */
309 for (i = status_info->noOfHosts, hp = status_info->hosts; i ; i--, hp++)
310 {
311 if (hp->notifyReqd)
312 {
313 work_to_do = TRUE;
314 break;
315 }
316 }
317
318 if (!work_to_do) return; /* No work found */
319
320 pid = fork();
321 if (pid == -1)
322 {
323 syslog(LOG_ERR, "Unable to fork notify process - %s", strerror(errno));
324 return;
325 }
326 if (pid) return;
327
328 /* Here in the child process. We continue until all the hosts marked */
329 /* as requiring notification have been duly notified. */
330 /* If one of the initial attempts fails, we sleep for a while and */
331 /* have another go. This is necessary because when we have crashed, */
332 /* (eg. a power outage) it is quite possible that we won't be able to */
333 /* contact all monitored hosts immediately on restart, either because */
334 /* they crashed too and take longer to come up (in which case the */
335 /* notification isn't really required), or more importantly if some */
336 /* router etc. needed to reach the monitored host has not come back */
337 /* up yet. In this case, we will be a bit late in re-establishing */
338 /* locks (after the grace period) but that is the best we can do. */
339 /* We try 10 times at 5 sec intervals, 10 more times at 1 minute */
340 /* intervals, then 24 more times at hourly intervals, finally */
341 /* giving up altogether if the host hasn't come back to life after */
342 /* 24 hours. */
343
344 for (attempts = 0; attempts < 44; attempts++)
345 {
346 work_to_do = FALSE; /* Unless anything fails */
347 for (i = status_info->noOfHosts, hp = status_info->hosts; i ; i--, hp++)
348 {
349 if (hp->notifyReqd)
350 {
351 if (notify_one_host(hp->hostname, attempts == 0))
352 {
353 hp->notifyReqd = FALSE;
354 sync_file();
355 }
356 else work_to_do = TRUE;
357 }
358 }
359 if (!work_to_do) break;
360 if (attempts < 10) sleep(5);
361 else if (attempts < 20) sleep(60);
362 else sleep(60*60);
363 }
364 exit(0);
365 }
366
367
368