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