hastd.c revision 206696 
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 206696 2010-04-16 06:47:29Z 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 (status != 0) {
298				pjdlog_error("Worker process (pid=%u) exited ungracefully: status=%d.",
299				    (unsigned int)res->hr_workerpid, status);
300				/* See above. */
301			} else {
302				pjdlog_debug(1,
303				    "Worker process (pid=%u) exited gracefully.",
304				    (unsigned int)res->hr_workerpid);
305			}
306			res->hr_workerpid = 0;
307		} else if (res->hr_remotein != NULL) {
308			char oaddr[256];
309
310			proto_remote_address(conn, oaddr, sizeof(oaddr));
311			pjdlog_debug(1,
312			    "Canceling half-open connection from %s on connection from %s.",
313			    oaddr, raddr);
314			proto_close(res->hr_remotein);
315			res->hr_remotein = NULL;
316		}
317	}
318
319	/*
320	 * Checks and cleanups are done.
321	 */
322
323	if (token == NULL) {
324		arc4random_buf(res->hr_token, sizeof(res->hr_token));
325		nvout = nv_alloc();
326		nv_add_uint8_array(nvout, res->hr_token,
327		    sizeof(res->hr_token), "token");
328		if (nv_error(nvout) != 0) {
329			pjdlog_common(LOG_ERR, 0, nv_error(nvout),
330			    "Unable to prepare return header for %s", raddr);
331			nv_add_stringf(nverr, "errmsg",
332			    "Remote node was unable to prepare return header: %s.",
333			    strerror(nv_error(nvout)));
334			goto fail;
335		}
336		if (hast_proto_send(NULL, conn, nvout, NULL, 0) < 0) {
337			int error = errno;
338
339			pjdlog_errno(LOG_ERR, "Unable to send response to %s",
340			    raddr);
341			nv_add_stringf(nverr, "errmsg",
342			    "Remote node was unable to send response: %s.",
343			    strerror(error));
344			goto fail;
345		}
346		res->hr_remotein = conn;
347		pjdlog_debug(1, "Incoming connection from %s configured.",
348		    raddr);
349	} else {
350		res->hr_remoteout = conn;
351		pjdlog_debug(1, "Outgoing connection to %s configured.", raddr);
352		hastd_secondary(res, nvin);
353	}
354	nv_free(nvin);
355	nv_free(nvout);
356	nv_free(nverr);
357	pjdlog_prefix_set("%s", "");
358	return;
359fail:
360	if (nv_error(nverr) != 0) {
361		pjdlog_common(LOG_ERR, 0, nv_error(nverr),
362		    "Unable to prepare error header for %s", raddr);
363		goto close;
364	}
365	if (hast_proto_send(NULL, conn, nverr, NULL, 0) < 0) {
366		pjdlog_errno(LOG_ERR, "Unable to send error to %s", raddr);
367		goto close;
368	}
369close:
370	if (nvin != NULL)
371		nv_free(nvin);
372	if (nvout != NULL)
373		nv_free(nvout);
374	if (nverr != NULL)
375		nv_free(nverr);
376	proto_close(conn);
377	pjdlog_prefix_set("%s", "");
378}
379
380static void
381main_loop(void)
382{
383	fd_set rfds, wfds;
384	int fd, maxfd, ret;
385
386	for (;;) {
387		if (sigchld_received) {
388			sigchld_received = false;
389			child_exit();
390		}
391		if (sighup_received) {
392			sighup_received = false;
393			hastd_reload();
394		}
395
396		maxfd = 0;
397		FD_ZERO(&rfds);
398		FD_ZERO(&wfds);
399
400		/* Setup descriptors for select(2). */
401#define	SETUP_FD(conn)	do {						\
402	fd = proto_descriptor(conn);					\
403	if (fd >= 0) {							\
404		maxfd = fd > maxfd ? fd : maxfd;			\
405		FD_SET(fd, &rfds);					\
406		FD_SET(fd, &wfds);					\
407	}								\
408} while (0)
409		SETUP_FD(cfg->hc_controlconn);
410		SETUP_FD(cfg->hc_listenconn);
411#undef	SETUP_FD
412
413		ret = select(maxfd + 1, &rfds, &wfds, NULL, NULL);
414		if (ret == -1) {
415			if (errno == EINTR)
416				continue;
417			KEEP_ERRNO((void)pidfile_remove(pfh));
418			pjdlog_exit(EX_OSERR, "select() failed");
419		}
420
421#define	ISSET_FD(conn)	\
422	(FD_ISSET((fd = proto_descriptor(conn)), &rfds) || FD_ISSET(fd, &wfds))
423		if (ISSET_FD(cfg->hc_controlconn))
424			control_handle(cfg);
425		if (ISSET_FD(cfg->hc_listenconn))
426			listen_accept();
427#undef	ISSET_FD
428	}
429}
430
431int
432main(int argc, char *argv[])
433{
434	const char *pidfile;
435	pid_t otherpid;
436	bool foreground;
437	int debuglevel;
438
439	g_gate_load();
440
441	foreground = false;
442	debuglevel = 0;
443	pidfile = HASTD_PIDFILE;
444
445	for (;;) {
446		int ch;
447
448		ch = getopt(argc, argv, "c:dFhP:");
449		if (ch == -1)
450			break;
451		switch (ch) {
452		case 'c':
453			cfgpath = optarg;
454			break;
455		case 'd':
456			debuglevel++;
457			break;
458		case 'F':
459			foreground = true;
460			break;
461		case 'P':
462			pidfile = optarg;
463			break;
464		case 'h':
465		default:
466			usage();
467		}
468	}
469	argc -= optind;
470	argv += optind;
471
472	pjdlog_debug_set(debuglevel);
473
474	pfh = pidfile_open(pidfile, 0600, &otherpid);
475	if (pfh == NULL) {
476		if (errno == EEXIST) {
477			pjdlog_exitx(EX_TEMPFAIL,
478			    "Another hastd is already running, pid: %jd.",
479			    (intmax_t)otherpid);
480		}
481		/* If we cannot create pidfile from other reasons, only warn. */
482		pjdlog_errno(LOG_WARNING, "Cannot open or create pidfile");
483	}
484
485	cfg = yy_config_parse(cfgpath);
486	assert(cfg != NULL);
487
488	signal(SIGHUP, sighandler);
489	signal(SIGCHLD, sighandler);
490
491	/* Listen on control address. */
492	if (proto_server(cfg->hc_controladdr, &cfg->hc_controlconn) < 0) {
493		KEEP_ERRNO((void)pidfile_remove(pfh));
494		pjdlog_exit(EX_OSERR, "Unable to listen on control address %s",
495		    cfg->hc_controladdr);
496	}
497	/* Listen for remote connections. */
498	if (proto_server(cfg->hc_listenaddr, &cfg->hc_listenconn) < 0) {
499		KEEP_ERRNO((void)pidfile_remove(pfh));
500		pjdlog_exit(EX_OSERR, "Unable to listen on address %s",
501		    cfg->hc_listenaddr);
502	}
503
504	if (!foreground) {
505		if (daemon(0, 0) < 0) {
506			KEEP_ERRNO((void)pidfile_remove(pfh));
507			pjdlog_exit(EX_OSERR, "Unable to daemonize");
508		}
509
510		/* Start logging to syslog. */
511		pjdlog_mode_set(PJDLOG_MODE_SYSLOG);
512
513		/* Write PID to a file. */
514		if (pidfile_write(pfh) < 0) {
515			pjdlog_errno(LOG_WARNING,
516			    "Unable to write PID to a file");
517		}
518	}
519
520	main_loop();
521
522	exit(0);
523}
524