hastd.c revision 204076 
1/*-
2 * Copyright (c) 2009-2010 The FreeBSD Foundation
3 * All rights reserved.
4 *
5 * This software was developed by Pawel Jakub Dawidek under sponsorship from
6 * the FreeBSD Foundation.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31__FBSDID("$FreeBSD: head/sbin/hastd/hastd.c 204076 2010-02-18 23:16:19Z pjd $");
32
33#include <sys/param.h>
34#include <sys/linker.h>
35#include <sys/module.h>
36#include <sys/wait.h>
37
38#include <assert.h>
39#include <err.h>
40#include <errno.h>
41#include <libutil.h>
42#include <signal.h>
43#include <stdbool.h>
44#include <stdio.h>
45#include <stdlib.h>
46#include <string.h>
47#include <sysexits.h>
48#include <unistd.h>
49
50#include <activemap.h>
51#include <pjdlog.h>
52
53#include "control.h"
54#include "hast.h"
55#include "hast_proto.h"
56#include "hastd.h"
57#include "subr.h"
58
59/* Path to configuration file. */
60static const char *cfgpath = HAST_CONFIG;
61/* Hastd configuration. */
62static struct hastd_config *cfg;
63/* Was SIGCHLD signal received? */
64static bool sigchld_received = false;
65/* Was SIGHUP signal received? */
66static bool sighup_received = false;
67/* Was SIGINT or SIGTERM signal received? */
68bool sigexit_received = false;
69/* PID file handle. */
70struct pidfh *pfh;
71
72static void
73usage(void)
74{
75
76	errx(EX_USAGE, "[-dFh] [-c config] [-P pidfile]");
77}
78
79static void
80sighandler(int sig)
81{
82
83	switch (sig) {
84	case SIGCHLD:
85		sigchld_received = true;
86		break;
87	case SIGHUP:
88		sighup_received = true;
89		break;
90	default:
91		assert(!"invalid condition");
92	}
93}
94
95static void
96g_gate_load(void)
97{
98
99	if (modfind("g_gate") == -1) {
100		/* Not present in kernel, try loading it. */
101		if (kldload("geom_gate") == -1 || modfind("g_gate") == -1) {
102			if (errno != EEXIST) {
103				pjdlog_exit(EX_OSERR,
104				    "Unable to load geom_gate module");
105			}
106		}
107	}
108}
109
110static void
111child_exit(void)
112{
113	struct hast_resource *res;
114	int status;
115	pid_t pid;
116
117	while ((pid = wait3(&status, WNOHANG, NULL)) > 0) {
118		/* Find resource related to the process that just exited. */
119		TAILQ_FOREACH(res, &cfg->hc_resources, hr_next) {
120			if (pid == res->hr_workerpid)
121				break;
122		}
123		if (res == NULL) {
124			/*
125			 * This can happen when new connection arrives and we
126			 * cancel child responsible for the old one.
127			 */
128			continue;
129		}
130		pjdlog_prefix_set("[%s] (%s) ", res->hr_name,
131		    role2str(res->hr_role));
132		if (WEXITSTATUS(status) == 0) {
133			pjdlog_debug(1,
134			    "Worker process exited gracefully (pid=%u).",
135			    (unsigned int)pid);
136		} else {
137			pjdlog_error("Worker process failed (pid=%u, status=%d).",
138			    (unsigned int)pid, WEXITSTATUS(status));
139		}
140		res->hr_workerpid = 0;
141		if (res->hr_role == HAST_ROLE_PRIMARY) {
142			sleep(1);
143			pjdlog_info("Restarting worker process.");
144			hastd_primary(res);
145		}
146		pjdlog_prefix_set("%s", "");
147	}
148}
149
150static void
151hastd_reload(void)
152{
153
154	/* TODO */
155	pjdlog_warning("Configuration reload is not implemented.");
156}
157
158static void
159listen_accept(void)
160{
161	struct hast_resource *res;
162	struct proto_conn *conn;
163	struct nv *nvin, *nvout, *nverr;
164	const char *resname;
165	const unsigned char *token;
166	char laddr[256], raddr[256];
167	size_t size;
168	pid_t pid;
169	int status;
170
171	proto_local_address(cfg->hc_listenconn, laddr, sizeof(laddr));
172	pjdlog_debug(1, "Accepting connection to %s.", laddr);
173
174	if (proto_accept(cfg->hc_listenconn, &conn) < 0) {
175		pjdlog_errno(LOG_ERR, "Unable to accept connection %s", laddr);
176		return;
177	}
178
179	proto_local_address(conn, laddr, sizeof(laddr));
180	proto_remote_address(conn, raddr, sizeof(raddr));
181	pjdlog_info("Connection from %s to %s.", laddr, raddr);
182
183	nvin = nvout = nverr = NULL;
184
185	/*
186	 * Before receiving any data see if remote host have access to any
187	 * resource.
188	 */
189	TAILQ_FOREACH(res, &cfg->hc_resources, hr_next) {
190		if (proto_address_match(conn, res->hr_remoteaddr))
191			break;
192	}
193	if (res == NULL) {
194		pjdlog_error("Client %s isn't known.", raddr);
195		goto close;
196	}
197	/* Ok, remote host can access at least one resource. */
198
199	if (hast_proto_recv_hdr(conn, &nvin) < 0) {
200		pjdlog_errno(LOG_ERR, "Unable to receive header from %s",
201		    raddr);
202		goto close;
203	}
204
205	resname = nv_get_string(nvin, "resource");
206	if (resname == NULL) {
207		pjdlog_error("No 'resource' field in the header received from %s.",
208		    raddr);
209		goto close;
210	}
211	pjdlog_debug(2, "%s: resource=%s", raddr, resname);
212	token = nv_get_uint8_array(nvin, &size, "token");
213	/*
214	 * NULL token means that this is first conection.
215	 */
216	if (token != NULL && size != sizeof(res->hr_token)) {
217		pjdlog_error("Received token of invalid size from %s (expected %zu, got %zu).",
218		    raddr, sizeof(res->hr_token), size);
219		goto close;
220	}
221
222	/*
223	 * From now on we want to send errors to the remote node.
224	 */
225	nverr = nv_alloc();
226
227	/* Find resource related to this connection. */
228	TAILQ_FOREACH(res, &cfg->hc_resources, hr_next) {
229		if (strcmp(resname, res->hr_name) == 0)
230			break;
231	}
232	/* Have we found the resource? */
233	if (res == NULL) {
234		pjdlog_error("No resource '%s' as requested by %s.",
235		    resname, raddr);
236		nv_add_stringf(nverr, "errmsg", "Resource not configured.");
237		goto fail;
238	}
239
240	/* Now that we know resource name setup log prefix. */
241	pjdlog_prefix_set("[%s] (%s) ", res->hr_name, role2str(res->hr_role));
242
243	/* Does the remote host have access to this resource? */
244	if (!proto_address_match(conn, res->hr_remoteaddr)) {
245		pjdlog_error("Client %s has no access to the resource.", raddr);
246		nv_add_stringf(nverr, "errmsg", "No access to the resource.");
247		goto fail;
248	}
249	/* Is the resource marked as secondary? */
250	if (res->hr_role != HAST_ROLE_SECONDARY) {
251		pjdlog_error("We act as %s for the resource and not as %s as requested by %s.",
252		    role2str(res->hr_role), role2str(HAST_ROLE_SECONDARY),
253		    raddr);
254		nv_add_stringf(nverr, "errmsg",
255		    "Remote node acts as %s for the resource and not as %s.",
256		    role2str(res->hr_role), role2str(HAST_ROLE_SECONDARY));
257		goto fail;
258	}
259	/* Does token (if exists) match? */
260	if (token != NULL && memcmp(token, res->hr_token,
261	    sizeof(res->hr_token)) != 0) {
262		pjdlog_error("Token received from %s doesn't match.", raddr);
263		nv_add_stringf(nverr, "errmsg", "Toke doesn't match.");
264		goto fail;
265	}
266	/*
267	 * If there is no token, but we have half-open connection
268	 * (only remotein) or full connection (worker process is running)
269	 * we have to cancel those and accept the new connection.
270	 */
271	if (token == NULL) {
272		assert(res->hr_remoteout == NULL);
273		pjdlog_debug(1, "Initial connection from %s.", raddr);
274		if (res->hr_workerpid != 0) {
275			assert(res->hr_remotein == NULL);
276			pjdlog_debug(1,
277			    "Worker process exists (pid=%u), stopping it.",
278			    (unsigned int)res->hr_workerpid);
279			/* Stop child process. */
280			if (kill(res->hr_workerpid, SIGINT) < 0) {
281				pjdlog_errno(LOG_ERR,
282				    "Unable to stop worker process (pid=%u)",
283				    (unsigned int)res->hr_workerpid);
284				/*
285				 * Other than logging the problem we
286				 * ignore it - nothing smart to do.
287				 */
288			}
289			/* Wait for it to exit. */
290			else if ((pid = waitpid(res->hr_workerpid,
291			    &status, 0)) != res->hr_workerpid) {
292				pjdlog_errno(LOG_ERR,
293				    "Waiting for worker process (pid=%u) failed",
294				    (unsigned int)res->hr_workerpid);
295				/* See above. */
296			} else if (status != 0) {
297				pjdlog_error("Worker process (pid=%u) exited ungracefully: status=%d.",
298				    (unsigned int)res->hr_workerpid, status);
299				/* See above. */
300			} else {
301				pjdlog_debug(1,
302				    "Worker process (pid=%u) exited gracefully.",
303				    (unsigned int)res->hr_workerpid);
304			}
305			res->hr_workerpid = 0;
306		} else if (res->hr_remotein != NULL) {
307			char oaddr[256];
308
309			proto_remote_address(conn, oaddr, sizeof(oaddr));
310			pjdlog_debug(1,
311			    "Canceling half-open connection from %s on connection from %s.",
312			    oaddr, raddr);
313			proto_close(res->hr_remotein);
314			res->hr_remotein = NULL;
315		}
316	}
317
318	/*
319	 * Checks and cleanups are done.
320	 */
321
322	if (token == NULL) {
323		arc4random_buf(res->hr_token, sizeof(res->hr_token));
324		nvout = nv_alloc();
325		nv_add_uint8_array(nvout, res->hr_token,
326		    sizeof(res->hr_token), "token");
327		if (nv_error(nvout) != 0) {
328			pjdlog_common(LOG_ERR, 0, nv_error(nvout),
329			    "Unable to prepare return header for %s", raddr);
330			nv_add_stringf(nverr, "errmsg",
331			    "Remote node was unable to prepare return header: %s.",
332			    strerror(nv_error(nvout)));
333			goto fail;
334		}
335		if (hast_proto_send(NULL, conn, nvout, NULL, 0) < 0) {
336			int error = errno;
337
338			pjdlog_errno(LOG_ERR, "Unable to send response to %s",
339			    raddr);
340			nv_add_stringf(nverr, "errmsg",
341			    "Remote node was unable to send response: %s.",
342			    strerror(error));
343			goto fail;
344		}
345		res->hr_remotein = conn;
346		pjdlog_debug(1, "Incoming connection from %s configured.",
347		    raddr);
348	} else {
349		res->hr_remoteout = conn;
350		pjdlog_debug(1, "Outgoing connection to %s configured.", raddr);
351		hastd_secondary(res, nvin);
352	}
353	nv_free(nvin);
354	nv_free(nvout);
355	nv_free(nverr);
356	pjdlog_prefix_set("%s", "");
357	return;
358fail:
359	if (nv_error(nverr) != 0) {
360		pjdlog_common(LOG_ERR, 0, nv_error(nverr),
361		    "Unable to prepare error header for %s", raddr);
362		goto close;
363	}
364	if (hast_proto_send(NULL, conn, nverr, NULL, 0) < 0) {
365		pjdlog_errno(LOG_ERR, "Unable to send error to %s", raddr);
366		goto close;
367	}
368close:
369	if (nvin != NULL)
370		nv_free(nvin);
371	if (nvout != NULL)
372		nv_free(nvout);
373	if (nverr != NULL)
374		nv_free(nverr);
375	proto_close(conn);
376	pjdlog_prefix_set("%s", "");
377}
378
379static void
380main_loop(void)
381{
382	fd_set rfds, wfds;
383	int fd, maxfd, ret;
384
385	for (;;) {
386		if (sigchld_received) {
387			sigchld_received = false;
388			child_exit();
389		}
390		if (sighup_received) {
391			sighup_received = false;
392			hastd_reload();
393		}
394
395		maxfd = 0;
396		FD_ZERO(&rfds);
397		FD_ZERO(&wfds);
398
399		/* Setup descriptors for select(2). */
400#define	SETUP_FD(conn)	do {						\
401	fd = proto_descriptor(conn);					\
402	if (fd >= 0) {							\
403		maxfd = fd > maxfd ? fd : maxfd;			\
404		FD_SET(fd, &rfds);					\
405		FD_SET(fd, &wfds);					\
406	}								\
407} while (0)
408		SETUP_FD(cfg->hc_controlconn);
409		SETUP_FD(cfg->hc_listenconn);
410#undef	SETUP_FD
411
412		ret = select(maxfd + 1, &rfds, &wfds, NULL, NULL);
413		if (ret == -1) {
414			if (errno == EINTR)
415				continue;
416			KEEP_ERRNO((void)pidfile_remove(pfh));
417			pjdlog_exit(EX_OSERR, "select() failed");
418		}
419
420#define	ISSET_FD(conn)	\
421	(FD_ISSET((fd = proto_descriptor(conn)), &rfds) || FD_ISSET(fd, &wfds))
422		if (ISSET_FD(cfg->hc_controlconn))
423			control_handle(cfg);
424		if (ISSET_FD(cfg->hc_listenconn))
425			listen_accept();
426#undef	ISSET_FD
427	}
428}
429
430int
431main(int argc, char *argv[])
432{
433	const char *pidfile;
434	pid_t otherpid;
435	bool foreground;
436	int debuglevel;
437
438	g_gate_load();
439
440	foreground = false;
441	debuglevel = 0;
442	pidfile = HASTD_PIDFILE;
443
444	for (;;) {
445		int ch;
446
447		ch = getopt(argc, argv, "c:dFhP:");
448		if (ch == -1)
449			break;
450		switch (ch) {
451		case 'c':
452			cfgpath = optarg;
453			break;
454		case 'd':
455			debuglevel++;
456			break;
457		case 'F':
458			foreground = true;
459			break;
460		case 'P':
461			pidfile = optarg;
462			break;
463		case 'h':
464		default:
465			usage();
466		}
467	}
468	argc -= optind;
469	argv += optind;
470
471	pjdlog_debug_set(debuglevel);
472
473	pfh = pidfile_open(pidfile, 0600, &otherpid);
474	if (pfh == NULL) {
475		if (errno == EEXIST) {
476			pjdlog_exitx(EX_TEMPFAIL,
477			    "Another hastd is already running, pid: %jd.",
478			    (intmax_t)otherpid);
479		}
480		/* If we cannot create pidfile from other reasons, only warn. */
481		pjdlog_errno(LOG_WARNING, "Cannot open or create pidfile");
482	}
483
484	cfg = yy_config_parse(cfgpath);
485	assert(cfg != NULL);
486
487	signal(SIGHUP, sighandler);
488	signal(SIGCHLD, sighandler);
489
490	/* Listen on control address. */
491	if (proto_server(cfg->hc_controladdr, &cfg->hc_controlconn) < 0) {
492		KEEP_ERRNO((void)pidfile_remove(pfh));
493		pjdlog_exit(EX_OSERR, "Unable to listen on control address %s",
494		    cfg->hc_controladdr);
495	}
496	/* Listen for remote connections. */
497	if (proto_server(cfg->hc_listenaddr, &cfg->hc_listenconn) < 0) {
498		KEEP_ERRNO((void)pidfile_remove(pfh));
499		pjdlog_exit(EX_OSERR, "Unable to listen on address %s",
500		    cfg->hc_listenaddr);
501	}
502
503	if (!foreground) {
504		if (daemon(0, 0) < 0) {
505			KEEP_ERRNO((void)pidfile_remove(pfh));
506			pjdlog_exit(EX_OSERR, "Unable to daemonize");
507		}
508
509		/* Start logging to syslog. */
510		pjdlog_mode_set(PJDLOG_MODE_SYSLOG);
511
512		/* Write PID to a file. */
513		if (pidfile_write(pfh) < 0) {
514			pjdlog_errno(LOG_WARNING,
515			    "Unable to write PID to a file");
516		}
517	}
518
519	main_loop();
520
521	exit(0);
522}
523