xref: /freebsd/sys/contrib/openzfs/cmd/zed/zed_conf.c (revision 180f822596ecc49d3074dcc9dfea9628aae1d48d)
1 /*
2  * This file is part of the ZFS Event Daemon (ZED).
3  *
4  * Developed at Lawrence Livermore National Laboratory (LLNL-CODE-403049).
5  * Copyright (C) 2013-2014 Lawrence Livermore National Security, LLC.
6  * Refer to the ZoL git commit log for authoritative copyright attribution.
7  *
8  * The contents of this file are subject to the terms of the
9  * Common Development and Distribution License Version 1.0 (CDDL-1.0).
10  * You can obtain a copy of the license from the top-level file
11  * "OPENSOLARIS.LICENSE" or at <http://opensource.org/licenses/CDDL-1.0>.
12  * You may not use this file except in compliance with the license.
13  */
14 
15 #include <assert.h>
16 #include <ctype.h>
17 #include <dirent.h>
18 #include <errno.h>
19 #include <fcntl.h>
20 #include <libgen.h>
21 #include <limits.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <sys/stat.h>
26 #include <sys/uio.h>
27 #include <unistd.h>
28 #include "zed.h"
29 #include "zed_conf.h"
30 #include "zed_file.h"
31 #include "zed_log.h"
32 #include "zed_strings.h"
33 
34 /*
35  * Return a new configuration with default values.
36  */
37 struct zed_conf *
38 zed_conf_create(void)
39 {
40 	struct zed_conf *zcp;
41 
42 	zcp = calloc(1, sizeof (*zcp));
43 	if (!zcp)
44 		goto nomem;
45 
46 	zcp->syslog_facility = LOG_DAEMON;
47 	zcp->min_events = ZED_MIN_EVENTS;
48 	zcp->max_events = ZED_MAX_EVENTS;
49 	zcp->pid_fd = -1;
50 	zcp->zedlets = NULL;		/* created via zed_conf_scan_dir() */
51 	zcp->state_fd = -1;		/* opened via zed_conf_open_state() */
52 	zcp->zfs_hdl = NULL;		/* opened via zed_event_init() */
53 	zcp->zevent_fd = -1;		/* opened via zed_event_init() */
54 
55 	if (!(zcp->conf_file = strdup(ZED_CONF_FILE)))
56 		goto nomem;
57 
58 	if (!(zcp->pid_file = strdup(ZED_PID_FILE)))
59 		goto nomem;
60 
61 	if (!(zcp->zedlet_dir = strdup(ZED_ZEDLET_DIR)))
62 		goto nomem;
63 
64 	if (!(zcp->state_file = strdup(ZED_STATE_FILE)))
65 		goto nomem;
66 
67 	return (zcp);
68 
69 nomem:
70 	zed_log_die("Failed to create conf: %s", strerror(errno));
71 	return (NULL);
72 }
73 
74 /*
75  * Destroy the configuration [zcp].
76  *
77  * Note: zfs_hdl & zevent_fd are destroyed via zed_event_fini().
78  */
79 void
80 zed_conf_destroy(struct zed_conf *zcp)
81 {
82 	if (!zcp)
83 		return;
84 
85 	if (zcp->state_fd >= 0) {
86 		if (close(zcp->state_fd) < 0)
87 			zed_log_msg(LOG_WARNING,
88 			    "Failed to close state file \"%s\": %s",
89 			    zcp->state_file, strerror(errno));
90 		zcp->state_fd = -1;
91 	}
92 	if (zcp->pid_file) {
93 		if ((unlink(zcp->pid_file) < 0) && (errno != ENOENT))
94 			zed_log_msg(LOG_WARNING,
95 			    "Failed to remove PID file \"%s\": %s",
96 			    zcp->pid_file, strerror(errno));
97 	}
98 	if (zcp->pid_fd >= 0) {
99 		if (close(zcp->pid_fd) < 0)
100 			zed_log_msg(LOG_WARNING,
101 			    "Failed to close PID file \"%s\": %s",
102 			    zcp->pid_file, strerror(errno));
103 		zcp->pid_fd = -1;
104 	}
105 	if (zcp->conf_file) {
106 		free(zcp->conf_file);
107 		zcp->conf_file = NULL;
108 	}
109 	if (zcp->pid_file) {
110 		free(zcp->pid_file);
111 		zcp->pid_file = NULL;
112 	}
113 	if (zcp->zedlet_dir) {
114 		free(zcp->zedlet_dir);
115 		zcp->zedlet_dir = NULL;
116 	}
117 	if (zcp->state_file) {
118 		free(zcp->state_file);
119 		zcp->state_file = NULL;
120 	}
121 	if (zcp->zedlets) {
122 		zed_strings_destroy(zcp->zedlets);
123 		zcp->zedlets = NULL;
124 	}
125 	free(zcp);
126 }
127 
128 /*
129  * Display command-line help and exit.
130  *
131  * If [got_err] is 0, output to stdout and exit normally;
132  * otherwise, output to stderr and exit with a failure status.
133  */
134 static void
135 _zed_conf_display_help(const char *prog, int got_err)
136 {
137 	FILE *fp = got_err ? stderr : stdout;
138 	int w1 = 4;			/* width of leading whitespace */
139 	int w2 = 8;			/* width of L-justified option field */
140 
141 	fprintf(fp, "Usage: %s [OPTION]...\n", (prog ? prog : "zed"));
142 	fprintf(fp, "\n");
143 	fprintf(fp, "%*c%*s %s\n", w1, 0x20, -w2, "-h",
144 	    "Display help.");
145 	fprintf(fp, "%*c%*s %s\n", w1, 0x20, -w2, "-L",
146 	    "Display license information.");
147 	fprintf(fp, "%*c%*s %s\n", w1, 0x20, -w2, "-V",
148 	    "Display version information.");
149 	fprintf(fp, "\n");
150 	fprintf(fp, "%*c%*s %s\n", w1, 0x20, -w2, "-v",
151 	    "Be verbose.");
152 	fprintf(fp, "%*c%*s %s\n", w1, 0x20, -w2, "-f",
153 	    "Force daemon to run.");
154 	fprintf(fp, "%*c%*s %s\n", w1, 0x20, -w2, "-F",
155 	    "Run daemon in the foreground.");
156 	fprintf(fp, "%*c%*s %s\n", w1, 0x20, -w2, "-I",
157 	    "Idle daemon until kernel module is (re)loaded.");
158 	fprintf(fp, "%*c%*s %s\n", w1, 0x20, -w2, "-M",
159 	    "Lock all pages in memory.");
160 	fprintf(fp, "%*c%*s %s\n", w1, 0x20, -w2, "-P",
161 	    "$PATH for ZED to use (only used by ZTS).");
162 	fprintf(fp, "%*c%*s %s\n", w1, 0x20, -w2, "-Z",
163 	    "Zero state file.");
164 	fprintf(fp, "\n");
165 #if 0
166 	fprintf(fp, "%*c%*s %s [%s]\n", w1, 0x20, -w2, "-c FILE",
167 	    "Read configuration from FILE.", ZED_CONF_FILE);
168 #endif
169 	fprintf(fp, "%*c%*s %s [%s]\n", w1, 0x20, -w2, "-d DIR",
170 	    "Read enabled ZEDLETs from DIR.", ZED_ZEDLET_DIR);
171 	fprintf(fp, "%*c%*s %s [%s]\n", w1, 0x20, -w2, "-p FILE",
172 	    "Write daemon's PID to FILE.", ZED_PID_FILE);
173 	fprintf(fp, "%*c%*s %s [%s]\n", w1, 0x20, -w2, "-s FILE",
174 	    "Write daemon's state to FILE.", ZED_STATE_FILE);
175 	fprintf(fp, "\n");
176 
177 	exit(got_err ? EXIT_FAILURE : EXIT_SUCCESS);
178 }
179 
180 /*
181  * Display license information to stdout and exit.
182  */
183 static void
184 _zed_conf_display_license(void)
185 {
186 	const char **pp;
187 	const char *text[] = {
188 	    "The ZFS Event Daemon (ZED) is distributed under the terms of the",
189 	    "  Common Development and Distribution License (CDDL-1.0)",
190 	    "  <http://opensource.org/licenses/CDDL-1.0>.",
191 	    "",
192 	    "Developed at Lawrence Livermore National Laboratory"
193 	    " (LLNL-CODE-403049).",
194 	    "",
195 	    NULL
196 	};
197 
198 	for (pp = text; *pp; pp++)
199 		printf("%s\n", *pp);
200 
201 	exit(EXIT_SUCCESS);
202 }
203 
204 /*
205  * Display version information to stdout and exit.
206  */
207 static void
208 _zed_conf_display_version(void)
209 {
210 	printf("%s-%s-%s\n",
211 	    ZFS_META_NAME, ZFS_META_VERSION, ZFS_META_RELEASE);
212 
213 	exit(EXIT_SUCCESS);
214 }
215 
216 /*
217  * Copy the [path] string to the [resultp] ptr.
218  * If [path] is not an absolute path, prefix it with the current working dir.
219  * If [resultp] is non-null, free its existing string before assignment.
220  */
221 static void
222 _zed_conf_parse_path(char **resultp, const char *path)
223 {
224 	char buf[PATH_MAX];
225 
226 	assert(resultp != NULL);
227 	assert(path != NULL);
228 
229 	if (*resultp)
230 		free(*resultp);
231 
232 	if (path[0] == '/') {
233 		*resultp = strdup(path);
234 	} else if (!getcwd(buf, sizeof (buf))) {
235 		zed_log_die("Failed to get current working dir: %s",
236 		    strerror(errno));
237 	} else if (strlcat(buf, "/", sizeof (buf)) >= sizeof (buf)) {
238 		zed_log_die("Failed to copy path: %s", strerror(ENAMETOOLONG));
239 	} else if (strlcat(buf, path, sizeof (buf)) >= sizeof (buf)) {
240 		zed_log_die("Failed to copy path: %s", strerror(ENAMETOOLONG));
241 	} else {
242 		*resultp = strdup(buf);
243 	}
244 	if (!*resultp)
245 		zed_log_die("Failed to copy path: %s", strerror(ENOMEM));
246 }
247 
248 /*
249  * Parse the command-line options into the configuration [zcp].
250  */
251 void
252 zed_conf_parse_opts(struct zed_conf *zcp, int argc, char **argv)
253 {
254 	const char * const opts = ":hLVc:d:p:P:s:vfFMZI";
255 	int opt;
256 
257 	if (!zcp || !argv || !argv[0])
258 		zed_log_die("Failed to parse options: Internal error");
259 
260 	opterr = 0;			/* suppress default getopt err msgs */
261 
262 	while ((opt = getopt(argc, argv, opts)) != -1) {
263 		switch (opt) {
264 		case 'h':
265 			_zed_conf_display_help(argv[0], EXIT_SUCCESS);
266 			break;
267 		case 'L':
268 			_zed_conf_display_license();
269 			break;
270 		case 'V':
271 			_zed_conf_display_version();
272 			break;
273 		case 'c':
274 			_zed_conf_parse_path(&zcp->conf_file, optarg);
275 			break;
276 		case 'd':
277 			_zed_conf_parse_path(&zcp->zedlet_dir, optarg);
278 			break;
279 		case 'I':
280 			zcp->do_idle = 1;
281 			break;
282 		case 'p':
283 			_zed_conf_parse_path(&zcp->pid_file, optarg);
284 			break;
285 		case 'P':
286 			_zed_conf_parse_path(&zcp->path, optarg);
287 			break;
288 		case 's':
289 			_zed_conf_parse_path(&zcp->state_file, optarg);
290 			break;
291 		case 'v':
292 			zcp->do_verbose = 1;
293 			break;
294 		case 'f':
295 			zcp->do_force = 1;
296 			break;
297 		case 'F':
298 			zcp->do_foreground = 1;
299 			break;
300 		case 'M':
301 			zcp->do_memlock = 1;
302 			break;
303 		case 'Z':
304 			zcp->do_zero = 1;
305 			break;
306 		case '?':
307 		default:
308 			if (optopt == '?')
309 				_zed_conf_display_help(argv[0], EXIT_SUCCESS);
310 
311 			fprintf(stderr, "%s: %s '-%c'\n\n", argv[0],
312 			    "Invalid option", optopt);
313 			_zed_conf_display_help(argv[0], EXIT_FAILURE);
314 			break;
315 		}
316 	}
317 }
318 
319 /*
320  * Parse the configuration file into the configuration [zcp].
321  *
322  * FIXME: Not yet implemented.
323  */
324 void
325 zed_conf_parse_file(struct zed_conf *zcp)
326 {
327 	if (!zcp)
328 		zed_log_die("Failed to parse config: %s", strerror(EINVAL));
329 }
330 
331 /*
332  * Scan the [zcp] zedlet_dir for files to exec based on the event class.
333  * Files must be executable by user, but not writable by group or other.
334  * Dotfiles are ignored.
335  *
336  * Return 0 on success with an updated set of zedlets,
337  * or -1 on error with errno set.
338  *
339  * FIXME: Check if zedlet_dir and all parent dirs are secure.
340  */
341 int
342 zed_conf_scan_dir(struct zed_conf *zcp)
343 {
344 	zed_strings_t *zedlets;
345 	DIR *dirp;
346 	struct dirent *direntp;
347 	char pathname[PATH_MAX];
348 	struct stat st;
349 	int n;
350 
351 	if (!zcp) {
352 		errno = EINVAL;
353 		zed_log_msg(LOG_ERR, "Failed to scan zedlet dir: %s",
354 		    strerror(errno));
355 		return (-1);
356 	}
357 	zedlets = zed_strings_create();
358 	if (!zedlets) {
359 		errno = ENOMEM;
360 		zed_log_msg(LOG_WARNING, "Failed to scan dir \"%s\": %s",
361 		    zcp->zedlet_dir, strerror(errno));
362 		return (-1);
363 	}
364 	dirp = opendir(zcp->zedlet_dir);
365 	if (!dirp) {
366 		int errno_bak = errno;
367 		zed_log_msg(LOG_WARNING, "Failed to open dir \"%s\": %s",
368 		    zcp->zedlet_dir, strerror(errno));
369 		zed_strings_destroy(zedlets);
370 		errno = errno_bak;
371 		return (-1);
372 	}
373 	while ((direntp = readdir(dirp))) {
374 		if (direntp->d_name[0] == '.')
375 			continue;
376 
377 		n = snprintf(pathname, sizeof (pathname),
378 		    "%s/%s", zcp->zedlet_dir, direntp->d_name);
379 		if ((n < 0) || (n >= sizeof (pathname))) {
380 			zed_log_msg(LOG_WARNING, "Failed to stat \"%s\": %s",
381 			    direntp->d_name, strerror(ENAMETOOLONG));
382 			continue;
383 		}
384 		if (stat(pathname, &st) < 0) {
385 			zed_log_msg(LOG_WARNING, "Failed to stat \"%s\": %s",
386 			    pathname, strerror(errno));
387 			continue;
388 		}
389 		if (!S_ISREG(st.st_mode)) {
390 			zed_log_msg(LOG_INFO,
391 			    "Ignoring \"%s\": not a regular file",
392 			    direntp->d_name);
393 			continue;
394 		}
395 		if ((st.st_uid != 0) && !zcp->do_force) {
396 			zed_log_msg(LOG_NOTICE,
397 			    "Ignoring \"%s\": not owned by root",
398 			    direntp->d_name);
399 			continue;
400 		}
401 		if (!(st.st_mode & S_IXUSR)) {
402 			zed_log_msg(LOG_INFO,
403 			    "Ignoring \"%s\": not executable by user",
404 			    direntp->d_name);
405 			continue;
406 		}
407 		if ((st.st_mode & S_IWGRP) && !zcp->do_force) {
408 			zed_log_msg(LOG_NOTICE,
409 			    "Ignoring \"%s\": writable by group",
410 			    direntp->d_name);
411 			continue;
412 		}
413 		if ((st.st_mode & S_IWOTH) && !zcp->do_force) {
414 			zed_log_msg(LOG_NOTICE,
415 			    "Ignoring \"%s\": writable by other",
416 			    direntp->d_name);
417 			continue;
418 		}
419 		if (zed_strings_add(zedlets, NULL, direntp->d_name) < 0) {
420 			zed_log_msg(LOG_WARNING,
421 			    "Failed to register \"%s\": %s",
422 			    direntp->d_name, strerror(errno));
423 			continue;
424 		}
425 		if (zcp->do_verbose)
426 			zed_log_msg(LOG_INFO,
427 			    "Registered zedlet \"%s\"", direntp->d_name);
428 	}
429 	if (closedir(dirp) < 0) {
430 		int errno_bak = errno;
431 		zed_log_msg(LOG_WARNING, "Failed to close dir \"%s\": %s",
432 		    zcp->zedlet_dir, strerror(errno));
433 		zed_strings_destroy(zedlets);
434 		errno = errno_bak;
435 		return (-1);
436 	}
437 	if (zcp->zedlets)
438 		zed_strings_destroy(zcp->zedlets);
439 
440 	zcp->zedlets = zedlets;
441 	return (0);
442 }
443 
444 /*
445  * Write the PID file specified in [zcp].
446  * Return 0 on success, -1 on error.
447  *
448  * This must be called after fork()ing to become a daemon (so the correct PID
449  * is recorded), but before daemonization is complete and the parent process
450  * exits (for synchronization with systemd).
451  */
452 int
453 zed_conf_write_pid(struct zed_conf *zcp)
454 {
455 	const mode_t dirmode = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
456 	const mode_t filemode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
457 	char buf[PATH_MAX];
458 	int n;
459 	char *p;
460 	mode_t mask;
461 	int rv;
462 
463 	if (!zcp || !zcp->pid_file) {
464 		errno = EINVAL;
465 		zed_log_msg(LOG_ERR, "Failed to create PID file: %s",
466 		    strerror(errno));
467 		return (-1);
468 	}
469 	assert(zcp->pid_fd == -1);
470 	/*
471 	 * Create PID file directory if needed.
472 	 */
473 	n = strlcpy(buf, zcp->pid_file, sizeof (buf));
474 	if (n >= sizeof (buf)) {
475 		errno = ENAMETOOLONG;
476 		zed_log_msg(LOG_ERR, "Failed to create PID file: %s",
477 		    strerror(errno));
478 		goto err;
479 	}
480 	p = strrchr(buf, '/');
481 	if (p)
482 		*p = '\0';
483 
484 	if ((mkdirp(buf, dirmode) < 0) && (errno != EEXIST)) {
485 		zed_log_msg(LOG_ERR, "Failed to create directory \"%s\": %s",
486 		    buf, strerror(errno));
487 		goto err;
488 	}
489 	/*
490 	 * Obtain PID file lock.
491 	 */
492 	mask = umask(0);
493 	umask(mask | 022);
494 	zcp->pid_fd = open(zcp->pid_file, (O_RDWR | O_CREAT), filemode);
495 	umask(mask);
496 	if (zcp->pid_fd < 0) {
497 		zed_log_msg(LOG_ERR, "Failed to open PID file \"%s\": %s",
498 		    zcp->pid_file, strerror(errno));
499 		goto err;
500 	}
501 	rv = zed_file_lock(zcp->pid_fd);
502 	if (rv < 0) {
503 		zed_log_msg(LOG_ERR, "Failed to lock PID file \"%s\": %s",
504 		    zcp->pid_file, strerror(errno));
505 		goto err;
506 	} else if (rv > 0) {
507 		pid_t pid = zed_file_is_locked(zcp->pid_fd);
508 		if (pid < 0) {
509 			zed_log_msg(LOG_ERR,
510 			    "Failed to test lock on PID file \"%s\"",
511 			    zcp->pid_file);
512 		} else if (pid > 0) {
513 			zed_log_msg(LOG_ERR,
514 			    "Found PID %d bound to PID file \"%s\"",
515 			    pid, zcp->pid_file);
516 		} else {
517 			zed_log_msg(LOG_ERR,
518 			    "Inconsistent lock state on PID file \"%s\"",
519 			    zcp->pid_file);
520 		}
521 		goto err;
522 	}
523 	/*
524 	 * Write PID file.
525 	 */
526 	n = snprintf(buf, sizeof (buf), "%d\n", (int)getpid());
527 	if ((n < 0) || (n >= sizeof (buf))) {
528 		errno = ERANGE;
529 		zed_log_msg(LOG_ERR, "Failed to write PID file \"%s\": %s",
530 		    zcp->pid_file, strerror(errno));
531 	} else if (zed_file_write_n(zcp->pid_fd, buf, n) != n) {
532 		zed_log_msg(LOG_ERR, "Failed to write PID file \"%s\": %s",
533 		    zcp->pid_file, strerror(errno));
534 	} else if (fdatasync(zcp->pid_fd) < 0) {
535 		zed_log_msg(LOG_ERR, "Failed to sync PID file \"%s\": %s",
536 		    zcp->pid_file, strerror(errno));
537 	} else {
538 		return (0);
539 	}
540 
541 err:
542 	if (zcp->pid_fd >= 0) {
543 		(void) close(zcp->pid_fd);
544 		zcp->pid_fd = -1;
545 	}
546 	return (-1);
547 }
548 
549 /*
550  * Open and lock the [zcp] state_file.
551  * Return 0 on success, -1 on error.
552  *
553  * FIXME: Move state information into kernel.
554  */
555 int
556 zed_conf_open_state(struct zed_conf *zcp)
557 {
558 	char dirbuf[PATH_MAX];
559 	mode_t dirmode = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
560 	int n;
561 	char *p;
562 	int rv;
563 
564 	if (!zcp || !zcp->state_file) {
565 		errno = EINVAL;
566 		zed_log_msg(LOG_ERR, "Failed to open state file: %s",
567 		    strerror(errno));
568 		return (-1);
569 	}
570 	n = strlcpy(dirbuf, zcp->state_file, sizeof (dirbuf));
571 	if (n >= sizeof (dirbuf)) {
572 		errno = ENAMETOOLONG;
573 		zed_log_msg(LOG_WARNING, "Failed to open state file: %s",
574 		    strerror(errno));
575 		return (-1);
576 	}
577 	p = strrchr(dirbuf, '/');
578 	if (p)
579 		*p = '\0';
580 
581 	if ((mkdirp(dirbuf, dirmode) < 0) && (errno != EEXIST)) {
582 		zed_log_msg(LOG_WARNING,
583 		    "Failed to create directory \"%s\": %s",
584 		    dirbuf, strerror(errno));
585 		return (-1);
586 	}
587 	if (zcp->state_fd >= 0) {
588 		if (close(zcp->state_fd) < 0) {
589 			zed_log_msg(LOG_WARNING,
590 			    "Failed to close state file \"%s\": %s",
591 			    zcp->state_file, strerror(errno));
592 			return (-1);
593 		}
594 	}
595 	if (zcp->do_zero)
596 		(void) unlink(zcp->state_file);
597 
598 	zcp->state_fd = open(zcp->state_file,
599 	    (O_RDWR | O_CREAT), (S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH));
600 	if (zcp->state_fd < 0) {
601 		zed_log_msg(LOG_WARNING, "Failed to open state file \"%s\": %s",
602 		    zcp->state_file, strerror(errno));
603 		return (-1);
604 	}
605 	rv = zed_file_lock(zcp->state_fd);
606 	if (rv < 0) {
607 		zed_log_msg(LOG_WARNING, "Failed to lock state file \"%s\": %s",
608 		    zcp->state_file, strerror(errno));
609 		return (-1);
610 	}
611 	if (rv > 0) {
612 		pid_t pid = zed_file_is_locked(zcp->state_fd);
613 		if (pid < 0) {
614 			zed_log_msg(LOG_WARNING,
615 			    "Failed to test lock on state file \"%s\"",
616 			    zcp->state_file);
617 		} else if (pid > 0) {
618 			zed_log_msg(LOG_WARNING,
619 			    "Found PID %d bound to state file \"%s\"",
620 			    pid, zcp->state_file);
621 		} else {
622 			zed_log_msg(LOG_WARNING,
623 			    "Inconsistent lock state on state file \"%s\"",
624 			    zcp->state_file);
625 		}
626 		return (-1);
627 	}
628 	return (0);
629 }
630 
631 /*
632  * Read the opened [zcp] state_file to obtain the eid & etime of the last event
633  * processed.  Write the state from the last event to the [eidp] & [etime] args
634  * passed by reference.  Note that etime[] is an array of size 2.
635  * Return 0 on success, -1 on error.
636  */
637 int
638 zed_conf_read_state(struct zed_conf *zcp, uint64_t *eidp, int64_t etime[])
639 {
640 	ssize_t len;
641 	struct iovec iov[3];
642 	ssize_t n;
643 
644 	if (!zcp || !eidp || !etime) {
645 		errno = EINVAL;
646 		zed_log_msg(LOG_ERR,
647 		    "Failed to read state file: %s", strerror(errno));
648 		return (-1);
649 	}
650 	if (lseek(zcp->state_fd, 0, SEEK_SET) == (off_t)-1) {
651 		zed_log_msg(LOG_WARNING,
652 		    "Failed to reposition state file offset: %s",
653 		    strerror(errno));
654 		return (-1);
655 	}
656 	len = 0;
657 	iov[0].iov_base = eidp;
658 	len += iov[0].iov_len = sizeof (*eidp);
659 	iov[1].iov_base = &etime[0];
660 	len += iov[1].iov_len = sizeof (etime[0]);
661 	iov[2].iov_base = &etime[1];
662 	len += iov[2].iov_len = sizeof (etime[1]);
663 
664 	n = readv(zcp->state_fd, iov, 3);
665 	if (n == 0) {
666 		*eidp = 0;
667 	} else if (n < 0) {
668 		zed_log_msg(LOG_WARNING,
669 		    "Failed to read state file \"%s\": %s",
670 		    zcp->state_file, strerror(errno));
671 		return (-1);
672 	} else if (n != len) {
673 		errno = EIO;
674 		zed_log_msg(LOG_WARNING,
675 		    "Failed to read state file \"%s\": Read %d of %d bytes",
676 		    zcp->state_file, n, len);
677 		return (-1);
678 	}
679 	return (0);
680 }
681 
682 /*
683  * Write the [eid] & [etime] of the last processed event to the opened
684  * [zcp] state_file.  Note that etime[] is an array of size 2.
685  * Return 0 on success, -1 on error.
686  */
687 int
688 zed_conf_write_state(struct zed_conf *zcp, uint64_t eid, int64_t etime[])
689 {
690 	ssize_t len;
691 	struct iovec iov[3];
692 	ssize_t n;
693 
694 	if (!zcp) {
695 		errno = EINVAL;
696 		zed_log_msg(LOG_ERR,
697 		    "Failed to write state file: %s", strerror(errno));
698 		return (-1);
699 	}
700 	if (lseek(zcp->state_fd, 0, SEEK_SET) == (off_t)-1) {
701 		zed_log_msg(LOG_WARNING,
702 		    "Failed to reposition state file offset: %s",
703 		    strerror(errno));
704 		return (-1);
705 	}
706 	len = 0;
707 	iov[0].iov_base = &eid;
708 	len += iov[0].iov_len = sizeof (eid);
709 	iov[1].iov_base = &etime[0];
710 	len += iov[1].iov_len = sizeof (etime[0]);
711 	iov[2].iov_base = &etime[1];
712 	len += iov[2].iov_len = sizeof (etime[1]);
713 
714 	n = writev(zcp->state_fd, iov, 3);
715 	if (n < 0) {
716 		zed_log_msg(LOG_WARNING,
717 		    "Failed to write state file \"%s\": %s",
718 		    zcp->state_file, strerror(errno));
719 		return (-1);
720 	}
721 	if (n != len) {
722 		errno = EIO;
723 		zed_log_msg(LOG_WARNING,
724 		    "Failed to write state file \"%s\": Wrote %d of %d bytes",
725 		    zcp->state_file, n, len);
726 		return (-1);
727 	}
728 	if (fdatasync(zcp->state_fd) < 0) {
729 		zed_log_msg(LOG_WARNING,
730 		    "Failed to sync state file \"%s\": %s",
731 		    zcp->state_file, strerror(errno));
732 		return (-1);
733 	}
734 	return (0);
735 }
736