hastd.c revision 207345 
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 207345 2010-04-28 22:26:30Z 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		proto_close(res->hr_ctrl);
141		res->hr_workerpid = 0;
142		if (res->hr_role == HAST_ROLE_PRIMARY) {
143			sleep(1);
144			pjdlog_info("Restarting worker process.");
145			hastd_primary(res);
146		}
147		pjdlog_prefix_set("%s", "");
148	}
149}
150
151static void
152hastd_reload(void)
153{
154
155	/* TODO */
156	pjdlog_warning("Configuration reload is not implemented.");
157}
158
159static void
160listen_accept(void)
161{
162	struct hast_resource *res;
163	struct proto_conn *conn;
164	struct nv *nvin, *nvout, *nverr;
165	const char *resname;
166	const unsigned char *token;
167	char laddr[256], raddr[256];
168	size_t size;
169	pid_t pid;
170	int status;
171
172	proto_local_address(cfg->hc_listenconn, laddr, sizeof(laddr));
173	pjdlog_debug(1, "Accepting connection to %s.", laddr);
174
175	if (proto_accept(cfg->hc_listenconn, &conn) < 0) {
176		pjdlog_errno(LOG_ERR, "Unable to accept connection %s", laddr);
177		return;
178	}
179
180	proto_local_address(conn, laddr, sizeof(laddr));
181	proto_remote_address(conn, raddr, sizeof(raddr));
182	pjdlog_info("Connection from %s to %s.", laddr, raddr);
183
184	nvin = nvout = nverr = NULL;
185
186	/*
187	 * Before receiving any data see if remote host have access to any
188	 * resource.
189	 */
190	TAILQ_FOREACH(res, &cfg->hc_resources, hr_next) {
191		if (proto_address_match(conn, res->hr_remoteaddr))
192			break;
193	}
194	if (res == NULL) {
195		pjdlog_error("Client %s isn't known.", raddr);
196		goto close;
197	}
198	/* Ok, remote host can access at least one resource. */
199
200	if (hast_proto_recv_hdr(conn, &nvin) < 0) {
201		pjdlog_errno(LOG_ERR, "Unable to receive header from %s",
202		    raddr);
203		goto close;
204	}
205
206	resname = nv_get_string(nvin, "resource");
207	if (resname == NULL) {
208		pjdlog_error("No 'resource' field in the header received from %s.",
209		    raddr);
210		goto close;
211	}
212	pjdlog_debug(2, "%s: resource=%s", raddr, resname);
213	token = nv_get_uint8_array(nvin, &size, "token");
214	/*
215	 * NULL token means that this is first conection.
216	 */
217	if (token != NULL && size != sizeof(res->hr_token)) {
218		pjdlog_error("Received token of invalid size from %s (expected %zu, got %zu).",
219		    raddr, sizeof(res->hr_token), size);
220		goto close;
221	}
222
223	/*
224	 * From now on we want to send errors to the remote node.
225	 */
226	nverr = nv_alloc();
227
228	/* Find resource related to this connection. */
229	TAILQ_FOREACH(res, &cfg->hc_resources, hr_next) {
230		if (strcmp(resname, res->hr_name) == 0)
231			break;
232	}
233	/* Have we found the resource? */
234	if (res == NULL) {
235		pjdlog_error("No resource '%s' as requested by %s.",
236		    resname, raddr);
237		nv_add_stringf(nverr, "errmsg", "Resource not configured.");
238		goto fail;
239	}
240
241	/* Now that we know resource name setup log prefix. */
242	pjdlog_prefix_set("[%s] (%s) ", res->hr_name, role2str(res->hr_role));
243
244	/* Does the remote host have access to this resource? */
245	if (!proto_address_match(conn, res->hr_remoteaddr)) {
246		pjdlog_error("Client %s has no access to the resource.", raddr);
247		nv_add_stringf(nverr, "errmsg", "No access to the resource.");
248		goto fail;
249	}
250	/* Is the resource marked as secondary? */
251	if (res->hr_role != HAST_ROLE_SECONDARY) {
252		pjdlog_error("We act as %s for the resource and not as %s as requested by %s.",
253		    role2str(res->hr_role), role2str(HAST_ROLE_SECONDARY),
254		    raddr);
255		nv_add_stringf(nverr, "errmsg",
256		    "Remote node acts as %s for the resource and not as %s.",
257		    role2str(res->hr_role), role2str(HAST_ROLE_SECONDARY));
258		goto fail;
259	}
260	/* Does token (if exists) match? */
261	if (token != NULL && memcmp(token, res->hr_token,
262	    sizeof(res->hr_token)) != 0) {
263		pjdlog_error("Token received from %s doesn't match.", raddr);
264		nv_add_stringf(nverr, "errmsg", "Toke doesn't match.");
265		goto fail;
266	}
267	/*
268	 * If there is no token, but we have half-open connection
269	 * (only remotein) or full connection (worker process is running)
270	 * we have to cancel those and accept the new connection.
271	 */
272	if (token == NULL) {
273		assert(res->hr_remoteout == NULL);
274		pjdlog_debug(1, "Initial connection from %s.", raddr);
275		if (res->hr_workerpid != 0) {
276			assert(res->hr_remotein == NULL);
277			pjdlog_debug(1,
278			    "Worker process exists (pid=%u), stopping it.",
279			    (unsigned int)res->hr_workerpid);
280			/* Stop child process. */
281			if (kill(res->hr_workerpid, SIGINT) < 0) {
282				pjdlog_errno(LOG_ERR,
283				    "Unable to stop worker process (pid=%u)",
284				    (unsigned int)res->hr_workerpid);
285				/*
286				 * Other than logging the problem we
287				 * ignore it - nothing smart to do.
288				 */
289			}
290			/* Wait for it to exit. */
291			else if ((pid = waitpid(res->hr_workerpid,
292			    &status, 0)) != res->hr_workerpid) {
293				pjdlog_errno(LOG_ERR,
294				    "Waiting for worker process (pid=%u) failed",
295				    (unsigned int)res->hr_workerpid);
296				/* See above. */
297			} else if (WEXITSTATUS(status) != 0) {
298				pjdlog_error("Worker process (pid=%u) exited ungracefully: status=%d.",
299				    (unsigned int)res->hr_workerpid,
300				    WEXITSTATUS(status));
301				/* See above. */
302			} else {
303				pjdlog_debug(1,
304				    "Worker process (pid=%u) exited gracefully.",
305				    (unsigned int)res->hr_workerpid);
306			}
307			res->hr_workerpid = 0;
308		} else if (res->hr_remotein != NULL) {
309			char oaddr[256];
310
311			proto_remote_address(conn, oaddr, sizeof(oaddr));
312			pjdlog_debug(1,
313			    "Canceling half-open connection from %s on connection from %s.",
314			    oaddr, raddr);
315			proto_close(res->hr_remotein);
316			res->hr_remotein = NULL;
317		}
318	}
319
320	/*
321	 * Checks and cleanups are done.
322	 */
323
324	if (token == NULL) {
325		arc4random_buf(res->hr_token, sizeof(res->hr_token));
326		nvout = nv_alloc();
327		nv_add_uint8_array(nvout, res->hr_token,
328		    sizeof(res->hr_token), "token");
329		if (nv_error(nvout) != 0) {
330			pjdlog_common(LOG_ERR, 0, nv_error(nvout),
331			    "Unable to prepare return header for %s", raddr);
332			nv_add_stringf(nverr, "errmsg",
333			    "Remote node was unable to prepare return header: %s.",
334			    strerror(nv_error(nvout)));
335			goto fail;
336		}
337		if (hast_proto_send(NULL, conn, nvout, NULL, 0) < 0) {
338			int error = errno;
339
340			pjdlog_errno(LOG_ERR, "Unable to send response to %s",
341			    raddr);
342			nv_add_stringf(nverr, "errmsg",
343			    "Remote node was unable to send response: %s.",
344			    strerror(error));
345			goto fail;
346		}
347		res->hr_remotein = conn;
348		pjdlog_debug(1, "Incoming connection from %s configured.",
349		    raddr);
350	} else {
351		res->hr_remoteout = conn;
352		pjdlog_debug(1, "Outgoing connection to %s configured.", raddr);
353		hastd_secondary(res, nvin);
354	}
355	nv_free(nvin);
356	nv_free(nvout);
357	nv_free(nverr);
358	pjdlog_prefix_set("%s", "");
359	return;
360fail:
361	if (nv_error(nverr) != 0) {
362		pjdlog_common(LOG_ERR, 0, nv_error(nverr),
363		    "Unable to prepare error header for %s", raddr);
364		goto close;
365	}
366	if (hast_proto_send(NULL, conn, nverr, NULL, 0) < 0) {
367		pjdlog_errno(LOG_ERR, "Unable to send error to %s", raddr);
368		goto close;
369	}
370close:
371	if (nvin != NULL)
372		nv_free(nvin);
373	if (nvout != NULL)
374		nv_free(nvout);
375	if (nverr != NULL)
376		nv_free(nverr);
377	proto_close(conn);
378	pjdlog_prefix_set("%s", "");
379}
380
381static void
382main_loop(void)
383{
384	fd_set rfds, wfds;
385	int fd, maxfd, ret;
386
387	for (;;) {
388		if (sigchld_received) {
389			sigchld_received = false;
390			child_exit();
391		}
392		if (sighup_received) {
393			sighup_received = false;
394			hastd_reload();
395		}
396
397		maxfd = 0;
398		FD_ZERO(&rfds);
399		FD_ZERO(&wfds);
400
401		/* Setup descriptors for select(2). */
402#define	SETUP_FD(conn)	do {						\
403	fd = proto_descriptor(conn);					\
404	if (fd >= 0) {							\
405		maxfd = fd > maxfd ? fd : maxfd;			\
406		FD_SET(fd, &rfds);					\
407		FD_SET(fd, &wfds);					\
408	}								\
409} while (0)
410		SETUP_FD(cfg->hc_controlconn);
411		SETUP_FD(cfg->hc_listenconn);
412#undef	SETUP_FD
413
414		ret = select(maxfd + 1, &rfds, &wfds, NULL, NULL);
415		if (ret == -1) {
416			if (errno == EINTR)
417				continue;
418			KEEP_ERRNO((void)pidfile_remove(pfh));
419			pjdlog_exit(EX_OSERR, "select() failed");
420		}
421
422#define	ISSET_FD(conn)	\
423	(FD_ISSET((fd = proto_descriptor(conn)), &rfds) || FD_ISSET(fd, &wfds))
424		if (ISSET_FD(cfg->hc_controlconn))
425			control_handle(cfg);
426		if (ISSET_FD(cfg->hc_listenconn))
427			listen_accept();
428#undef	ISSET_FD
429	}
430}
431
432int
433main(int argc, char *argv[])
434{
435	const char *pidfile;
436	pid_t otherpid;
437	bool foreground;
438	int debuglevel;
439
440	g_gate_load();
441
442	foreground = false;
443	debuglevel = 0;
444	pidfile = HASTD_PIDFILE;
445
446	for (;;) {
447		int ch;
448
449		ch = getopt(argc, argv, "c:dFhP:");
450		if (ch == -1)
451			break;
452		switch (ch) {
453		case 'c':
454			cfgpath = optarg;
455			break;
456		case 'd':
457			debuglevel++;
458			break;
459		case 'F':
460			foreground = true;
461			break;
462		case 'P':
463			pidfile = optarg;
464			break;
465		case 'h':
466		default:
467			usage();
468		}
469	}
470	argc -= optind;
471	argv += optind;
472
473	pjdlog_debug_set(debuglevel);
474
475	pfh = pidfile_open(pidfile, 0600, &otherpid);
476	if (pfh == NULL) {
477		if (errno == EEXIST) {
478			pjdlog_exitx(EX_TEMPFAIL,
479			    "Another hastd is already running, pid: %jd.",
480			    (intmax_t)otherpid);
481		}
482		/* If we cannot create pidfile from other reasons, only warn. */
483		pjdlog_errno(LOG_WARNING, "Cannot open or create pidfile");
484	}
485
486	cfg = yy_config_parse(cfgpath);
487	assert(cfg != NULL);
488
489	signal(SIGHUP, sighandler);
490	signal(SIGCHLD, sighandler);
491
492	/* Listen on control address. */
493	if (proto_server(cfg->hc_controladdr, &cfg->hc_controlconn) < 0) {
494		KEEP_ERRNO((void)pidfile_remove(pfh));
495		pjdlog_exit(EX_OSERR, "Unable to listen on control address %s",
496		    cfg->hc_controladdr);
497	}
498	/* Listen for remote connections. */
499	if (proto_server(cfg->hc_listenaddr, &cfg->hc_listenconn) < 0) {
500		KEEP_ERRNO((void)pidfile_remove(pfh));
501		pjdlog_exit(EX_OSERR, "Unable to listen on address %s",
502		    cfg->hc_listenaddr);
503	}
504
505	if (!foreground) {
506		if (daemon(0, 0) < 0) {
507			KEEP_ERRNO((void)pidfile_remove(pfh));
508			pjdlog_exit(EX_OSERR, "Unable to daemonize");
509		}
510
511		/* Start logging to syslog. */
512		pjdlog_mode_set(PJDLOG_MODE_SYSLOG);
513
514		/* Write PID to a file. */
515		if (pidfile_write(pfh) < 0) {
516			pjdlog_errno(LOG_WARNING,
517			    "Unable to write PID to a file");
518		}
519	}
520
521	main_loop();
522
523	exit(0);
524}
525