Avoid per-element initializers.
[dss.git] / dss.c
1 /*
2 * Copyright (C) 2008-2011 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6 #include <string.h>
7 #include <stdlib.h>
8 #include <stdarg.h>
9 #include <assert.h>
10 #include <errno.h>
11 #include <sys/types.h>
12 #include <signal.h>
13 #include <ctype.h>
14 #include <sys/stat.h>
15 #include <unistd.h>
16 #include <inttypes.h>
17 #include <sys/time.h>
18 #include <time.h>
19 #include <sys/wait.h>
20 #include <fnmatch.h>
21 #include <limits.h>
22
23
24 #include "gcc-compat.h"
25 #include "cmdline.h"
26 #include "log.h"
27 #include "string.h"
28 #include "error.h"
29 #include "fd.h"
30 #include "exec.h"
31 #include "daemon.h"
32 #include "signal.h"
33 #include "df.h"
34 #include "time.h"
35 #include "snap.h"
36
37 /** Command line and config file options. */
38 static struct gengetopt_args_info conf;
39 /** Non-NULL if we log to a file. */
40 static FILE *logfile;
41 /** The read end of the signal pipe */
42 static int signal_pipe;
43 /** Process id of current pre-create-hook/rsync/post-create-hook process. */
44 static pid_t create_pid;
45 /** Whether the pre-create-hook/rsync/post-create-hook is currently stopped. */
46 static int create_process_stopped;
47 /** Process id of current pre-remove/rm/post-remove process. */
48 static pid_t remove_pid;
49 /** When the next snapshot is due. */
50 static int64_t next_snapshot_time;
51 /** When to try to remove something. */
52 static struct timeval next_removal_check;
53 /** Creation time of the snapshot currently being created. */
54 static int64_t current_snapshot_creation_time;
55 /** The snapshot currently being removed. */
56 struct snapshot *snapshot_currently_being_removed;
57 /** Needed by the post-create hook. */
58 static char *path_to_last_complete_snapshot;
59 static char *name_of_reference_snapshot;
60 /** \sa \ref snap.h for details. */
61 enum hook_status snapshot_creation_status;
62 /** \sa \ref snap.h for details. */
63 enum hook_status snapshot_removal_status;
64
65
66 DEFINE_DSS_ERRLIST;
67 static const char *hook_status_description[] = {HOOK_STATUS_ARRAY};
68
69 /* may be called with ds == NULL. */
70 static int disk_space_low(struct disk_space *ds)
71 {
72 struct disk_space ds_struct;
73
74 if (!ds) {
75 int ret = get_disk_space(".", &ds_struct);
76 if (ret < 0)
77 return ret;
78 ds = &ds_struct;
79 }
80 if (conf.min_free_mb_arg)
81 if (ds->free_mb < conf.min_free_mb_arg)
82 return 1;
83 if (conf.min_free_percent_arg)
84 if (ds->percent_free < conf.min_free_percent_arg)
85 return 1;
86 if (conf.min_free_percent_inodes_arg)
87 if (ds->percent_free_inodes < conf.min_free_percent_inodes_arg)
88 return 1;
89 return 0;
90 }
91
92 static void dump_dss_config(const char *msg)
93 {
94 const char dash[] = "-----------------------------";
95 int ret;
96 FILE *log = logfile? logfile : stderr;
97 struct disk_space ds;
98 int64_t now = get_current_time();
99
100 if (conf.loglevel_arg > INFO)
101 return;
102
103 fprintf(log, "%s <%s config> %s\n", dash, msg, dash);
104 fprintf(log, "\n*** disk space ***\n\n");
105 ret = get_disk_space(".", &ds);
106 if (ret >= 0) {
107 DSS_INFO_LOG("disk space low: %s\n", disk_space_low(&ds)?
108 "yes" : "no");
109 log_disk_space(&ds);
110 } else
111 DSS_ERROR_LOG("can not get free disk space: %s\n",
112 dss_strerror(-ret));
113
114 /* we continue on errors from get_disk_space */
115
116 fprintf(log, "\n*** command line and config file options ***\n\n");
117 cmdline_parser_dump(log, &conf);
118 fprintf(log, "\n*** internal state ***\n\n");
119 fprintf(log,
120 "pid: %d\n"
121 "logile: %s\n"
122 "snapshot_currently_being_removed: %s\n"
123 "path_to_last_complete_snapshot: %s\n"
124 "reference_snapshot: %s\n"
125 "snapshot_creation_status: %s\n"
126 "snapshot_removal_status: %s\n"
127 ,
128 (int) getpid(),
129 logfile? conf.logfile_arg : "stderr",
130 snapshot_currently_being_removed?
131 snapshot_currently_being_removed->name : "(none)",
132 path_to_last_complete_snapshot?
133 path_to_last_complete_snapshot : "(none)",
134 name_of_reference_snapshot?
135 name_of_reference_snapshot : "(none)",
136 hook_status_description[snapshot_creation_status],
137 hook_status_description[snapshot_removal_status]
138 );
139 if (create_pid != 0)
140 fprintf(log,
141 "create_pid: %" PRId32 "\n"
142 "create process is %sstopped\n"
143 ,
144 create_pid,
145 create_process_stopped? "" : "not "
146 );
147 if (remove_pid != 0)
148 fprintf(log, "remove_pid: %" PRId32 "\n", remove_pid);
149 if (next_snapshot_time != 0)
150 fprintf(log, "next snapshot due in %" PRId64 " seconds\n",
151 next_snapshot_time - now);
152 if (current_snapshot_creation_time != 0)
153 fprintf(log, "current_snapshot_creation_time: %"
154 PRId64 " (%" PRId64 " seconds ago)\n",
155 current_snapshot_creation_time,
156 now - current_snapshot_creation_time
157 );
158 if (next_removal_check.tv_sec != 0) {
159 fprintf(log, "next removal check: %llu (%llu seconds ago)\n",
160 (long long unsigned)next_removal_check.tv_sec,
161 now - (long long unsigned)next_removal_check.tv_sec
162 );
163
164 }
165 fprintf(log, "%s </%s config> %s\n", dash, msg, dash);
166 }
167
168 /* a litte cpp magic helps to DRY */
169 #define COMMANDS \
170 COMMAND(ls) \
171 COMMAND(create) \
172 COMMAND(prune) \
173 COMMAND(run)
174 #define COMMAND(x) static int com_ ##x(void);
175 COMMANDS
176 #undef COMMAND
177 #define COMMAND(x) if (conf.x ##_given) return com_ ##x();
178 static int call_command_handler(void)
179 {
180 COMMANDS
181 DSS_EMERG_LOG("BUG: did not find command handler\n");
182 return -E_BUG;
183 }
184 #undef COMMAND
185 #undef COMMANDS
186
187 /**
188 * The log function of dss.
189 *
190 * \param ll Loglevel.
191 * \param fml Usual format string.
192 *
193 * All DSS_XXX_LOG() macros use this function.
194 */
195 __printf_2_3 void dss_log(int ll, const char* fmt,...)
196 {
197 va_list argp;
198 FILE *outfd;
199 struct tm *tm;
200 time_t t1;
201 char str[255] = "";
202
203 if (ll < conf.loglevel_arg)
204 return;
205 outfd = logfile? logfile : stderr;
206 time(&t1);
207 tm = localtime(&t1);
208 strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
209 fprintf(outfd, "%s ", str);
210 if (conf.loglevel_arg <= INFO)
211 fprintf(outfd, "%i: ", ll);
212 va_start(argp, fmt);
213 vfprintf(outfd, fmt, argp);
214 va_end(argp);
215 }
216
217 /**
218 * Print a message either to stdout or to the log file.
219 */
220 static __printf_1_2 void dss_msg(const char* fmt,...)
221 {
222 FILE *outfd = conf.daemon_given? logfile : stdout;
223 va_list argp;
224 va_start(argp, fmt);
225 vfprintf(outfd, fmt, argp);
226 va_end(argp);
227 }
228
229 static void dss_get_snapshot_list(struct snapshot_list *sl)
230 {
231 get_snapshot_list(sl, conf.unit_interval_arg, conf.num_intervals_arg);
232 }
233
234 static int64_t compute_next_snapshot_time(void)
235 {
236 int64_t x = 0, now = get_current_time(), unit_interval
237 = 24 * 3600 * conf.unit_interval_arg, ret;
238 unsigned wanted = desired_number_of_snapshots(0, conf.num_intervals_arg),
239 num_complete_snapshots = 0;
240 int i;
241 struct snapshot *s = NULL;
242 struct snapshot_list sl;
243
244 dss_get_snapshot_list(&sl);
245 FOR_EACH_SNAPSHOT(s, i, &sl) {
246 if (!(s->flags & SS_COMPLETE))
247 continue;
248 num_complete_snapshots++;
249 x += s->completion_time - s->creation_time;
250 }
251 assert(x >= 0);
252
253 ret = now;
254 if (num_complete_snapshots == 0)
255 goto out;
256 x /= num_complete_snapshots; /* avg time to create one snapshot */
257 if (unit_interval < x * wanted) /* oops, no sleep at all */
258 goto out;
259 ret = s->completion_time + unit_interval / wanted - x;
260 out:
261 free_snapshot_list(&sl);
262 return ret;
263 }
264
265 static inline void invalidate_next_snapshot_time(void)
266 {
267 next_snapshot_time = 0;
268 }
269
270 static inline int next_snapshot_time_is_valid(void)
271 {
272 return next_snapshot_time != 0;
273 }
274
275 static int next_snapshot_is_due(void)
276 {
277 int64_t now = get_current_time();
278
279 if (!next_snapshot_time_is_valid())
280 next_snapshot_time = compute_next_snapshot_time();
281 if (next_snapshot_time <= now) {
282 DSS_DEBUG_LOG("next snapshot: now\n");
283 return 1;
284 }
285 DSS_DEBUG_LOG("next snapshot due in %" PRId64 " seconds\n",
286 next_snapshot_time - now);
287 return 0;
288 }
289
290 static void pre_create_hook(void)
291 {
292 assert(snapshot_creation_status == HS_READY);
293 /* make sure that the next snapshot time will be recomputed */
294 invalidate_next_snapshot_time();
295 DSS_DEBUG_LOG("executing %s\n", conf.pre_create_hook_arg);
296 dss_exec_cmdline_pid(&create_pid, conf.pre_create_hook_arg);
297 snapshot_creation_status = HS_PRE_RUNNING;
298 }
299
300 static void pre_remove_hook(struct snapshot *s, const char *why)
301 {
302 char *cmd;
303
304 if (!s)
305 return;
306 DSS_DEBUG_LOG("%s snapshot %s\n", why, s->name);
307 assert(snapshot_removal_status == HS_READY);
308 assert(remove_pid == 0);
309 assert(!snapshot_currently_being_removed);
310
311 snapshot_currently_being_removed = dss_malloc(sizeof(struct snapshot));
312 *snapshot_currently_being_removed = *s;
313 snapshot_currently_being_removed->name = dss_strdup(s->name);
314
315 cmd = make_message("%s %s/%s", conf.pre_remove_hook_arg,
316 conf.dest_dir_arg, s->name);
317 DSS_DEBUG_LOG("executing %s\n", cmd);
318 dss_exec_cmdline_pid(&remove_pid, cmd);
319 free(cmd);
320 snapshot_removal_status = HS_PRE_RUNNING;
321 }
322
323 static int exec_rm(void)
324 {
325 struct snapshot *s = snapshot_currently_being_removed;
326 char *new_name = being_deleted_name(s);
327 char *argv[4];
328 int ret;
329
330 argv[0] = "rm";
331 argv[1] = "-rf";
332 argv[2] = new_name;
333 argv[3] = NULL;
334
335 assert(snapshot_removal_status == HS_PRE_SUCCESS);
336 assert(remove_pid == 0);
337
338 DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
339 ret = dss_rename(s->name, new_name);
340 if (ret < 0)
341 goto out;
342 dss_exec(&remove_pid, argv[0], argv);
343 snapshot_removal_status = HS_RUNNING;
344 out:
345 free(new_name);
346 return ret;
347 }
348
349 static int snapshot_is_being_created(struct snapshot *s)
350 {
351 return s->creation_time == current_snapshot_creation_time;
352 }
353
354 static struct snapshot *find_orphaned_snapshot(struct snapshot_list *sl)
355 {
356 struct snapshot *s;
357 int i;
358
359 DSS_DEBUG_LOG("looking for orphaned snapshots\n");
360 FOR_EACH_SNAPSHOT(s, i, sl) {
361 if (snapshot_is_being_created(s))
362 continue;
363 /*
364 * We know that no rm is currently running, so if s is marked
365 * as being deleted, a previously started rm must have failed.
366 */
367 if (s->flags & SS_BEING_DELETED)
368 return s;
369
370 if (s->flags & SS_COMPLETE) /* good snapshot */
371 continue;
372 /*
373 * This snapshot is incomplete and it is not the snapshot
374 * currently being created. However, we must not remove it if
375 * rsync is about to be restarted. As only the newest snapshot
376 * can be restarted, this snapshot is orphaned if it is not the
377 * newest snapshot or if we are not about to restart rsync.
378 */
379 if (get_newest_snapshot(sl) != s)
380 return s;
381 if (snapshot_creation_status != HS_NEEDS_RESTART)
382 return s;
383 }
384 /* no orphaned snapshots */
385 return NULL;
386 }
387
388 static int is_reference_snapshot(struct snapshot *s)
389 {
390 if (!name_of_reference_snapshot)
391 return 0;
392 return strcmp(s->name, name_of_reference_snapshot)? 0 : 1;
393 }
394
395 /*
396 * return: 0: no redundant snapshots, 1: rm process started, negative: error
397 */
398 static struct snapshot *find_redundant_snapshot(struct snapshot_list *sl)
399 {
400 int i, interval;
401 struct snapshot *s;
402 unsigned missing = 0;
403
404 DSS_DEBUG_LOG("looking for intervals containing too many snapshots\n");
405 for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
406 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
407 unsigned num = sl->interval_count[interval];
408 struct snapshot *victim = NULL, *prev = NULL;
409 int64_t score = LONG_MAX;
410
411 if (keep >= num)
412 missing += keep - num;
413 // DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
414 // interval, keep, num, missing);
415 if (keep + missing >= num)
416 continue;
417 /* redundant snapshot in this interval, pick snapshot with lowest score */
418 FOR_EACH_SNAPSHOT(s, i, sl) {
419 int64_t this_score;
420
421 if (snapshot_is_being_created(s))
422 continue;
423 if (is_reference_snapshot(s))
424 continue;
425 //DSS_DEBUG_LOG("checking %s\n", s->name);
426 if (s->interval > interval) {
427 prev = s;
428 continue;
429 }
430 if (s->interval < interval)
431 break;
432 if (!victim) {
433 victim = s;
434 prev = s;
435 continue;
436 }
437 assert(prev);
438 /* check if s is a better victim */
439 this_score = s->creation_time - prev->creation_time;
440 assert(this_score >= 0);
441 //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
442 if (this_score < score) {
443 score = this_score;
444 victim = s;
445 }
446 prev = s;
447 }
448 assert(victim);
449 return victim;
450 }
451 return NULL;
452 }
453
454 static struct snapshot *find_outdated_snapshot(struct snapshot_list *sl)
455 {
456 int i;
457 struct snapshot *s;
458
459 DSS_DEBUG_LOG("looking for snapshots belonging to intervals >= %d\n",
460 conf.num_intervals_arg);
461 FOR_EACH_SNAPSHOT(s, i, sl) {
462 if (snapshot_is_being_created(s))
463 continue;
464 if (is_reference_snapshot(s))
465 continue;
466 if (s->interval < conf.num_intervals_arg)
467 continue;
468 return s;
469 }
470 return NULL;
471 }
472
473 struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
474 {
475 int i;
476 struct snapshot *s;
477 FOR_EACH_SNAPSHOT(s, i, sl) {
478 if (snapshot_is_being_created(s))
479 continue;
480 if (is_reference_snapshot(s))
481 continue;
482 DSS_INFO_LOG("oldest removable snapshot: %s\n", s->name);
483 return s;
484 }
485 return NULL;
486 }
487
488 static int rename_incomplete_snapshot(int64_t start)
489 {
490 char *old_name;
491 int ret;
492
493 free(path_to_last_complete_snapshot);
494 ret = complete_name(start, get_current_time(),
495 &path_to_last_complete_snapshot);
496 if (ret < 0)
497 return ret;
498 old_name = incomplete_name(start);
499 ret = dss_rename(old_name, path_to_last_complete_snapshot);
500 if (ret >= 0)
501 DSS_NOTICE_LOG("%s -> %s\n", old_name,
502 path_to_last_complete_snapshot);
503 free(old_name);
504 return ret;
505 }
506
507 static int try_to_free_disk_space(void)
508 {
509 int ret;
510 struct snapshot_list sl;
511 struct snapshot *victim;
512 struct timeval now;
513 const char *why;
514 int low_disk_space;
515
516 ret = disk_space_low(NULL);
517 if (ret < 0)
518 return ret;
519 low_disk_space = ret;
520 gettimeofday(&now, NULL);
521 if (tv_diff(&next_removal_check, &now, NULL) > 0)
522 return 0;
523 if (!low_disk_space) {
524 if (conf.keep_redundant_given)
525 return 0;
526 if (snapshot_creation_status != HS_READY)
527 return 0;
528 if (next_snapshot_is_due())
529 return 0;
530 }
531 dss_get_snapshot_list(&sl);
532 ret = 0;
533 if (!low_disk_space && sl.num_snapshots <= 1)
534 goto out;
535 why = "outdated";
536 victim = find_outdated_snapshot(&sl);
537 if (victim)
538 goto remove;
539 why = "redundant";
540 victim = find_redundant_snapshot(&sl);
541 if (victim)
542 goto remove;
543 /* try harder only if disk space is low */
544 if (!low_disk_space)
545 goto out;
546 why = "orphaned";
547 victim = find_orphaned_snapshot(&sl);
548 if (victim)
549 goto remove;
550 DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
551 victim = find_oldest_removable_snapshot(&sl);
552 if (victim)
553 goto remove;
554 DSS_CRIT_LOG("uhuhu: disk space low and nothing to remove\n");
555 ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
556 goto out;
557 remove:
558 pre_remove_hook(victim, why);
559 out:
560 free_snapshot_list(&sl);
561 return ret;
562 }
563
564 static void post_create_hook(void)
565 {
566 char *cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
567 conf.dest_dir_arg, path_to_last_complete_snapshot);
568 DSS_NOTICE_LOG("executing %s\n", cmd);
569 dss_exec_cmdline_pid(&create_pid, cmd);
570 free(cmd);
571 snapshot_creation_status = HS_POST_RUNNING;
572 }
573
574 static void post_remove_hook(void)
575 {
576 char *cmd;
577 struct snapshot *s = snapshot_currently_being_removed;
578
579 assert(s);
580
581 cmd = make_message("%s %s/%s", conf.post_remove_hook_arg,
582 conf.dest_dir_arg, s->name);
583 DSS_NOTICE_LOG("executing %s\n", cmd);
584 dss_exec_cmdline_pid(&remove_pid, cmd);
585 free(cmd);
586 snapshot_removal_status = HS_POST_RUNNING;
587 }
588
589 static void dss_kill(pid_t pid, int sig, const char *msg)
590 {
591 const char *signame, *process_name;
592
593 if (pid == 0)
594 return;
595 switch (sig) {
596 case SIGTERM: signame = "TERM"; break;
597 case SIGSTOP: signame = "STOP"; break;
598 case SIGCONT: signame = "CONT"; break;
599 default: signame = "????";
600 }
601
602 if (pid == create_pid)
603 process_name = "create";
604 else if (pid == remove_pid)
605 process_name = "remove";
606 else process_name = "??????";
607
608 if (msg)
609 DSS_INFO_LOG("%s\n", msg);
610 DSS_DEBUG_LOG("sending signal %d (%s) to pid %d (%s process)\n",
611 sig, signame, (int)pid, process_name);
612 if (kill(pid, sig) >= 0)
613 return;
614 DSS_INFO_LOG("failed to send signal %d (%s) to pid %d (%s process)\n",
615 sig, signame, (int)pid, process_name);
616 }
617
618 static void stop_create_process(void)
619 {
620 if (create_process_stopped)
621 return;
622 dss_kill(create_pid, SIGSTOP, "suspending create process");
623 create_process_stopped = 1;
624 }
625
626 static void restart_create_process(void)
627 {
628 if (!create_process_stopped)
629 return;
630 dss_kill(create_pid, SIGCONT, "resuming create process");
631 create_process_stopped = 0;
632 }
633
634 /**
635 * Print a log message about the exit status of a child.
636 */
637 static void log_termination_msg(pid_t pid, int status)
638 {
639 if (WIFEXITED(status))
640 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
641 WEXITSTATUS(status));
642 else if (WIFSIGNALED(status))
643 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
644 WTERMSIG(status));
645 else
646 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
647 }
648
649 static int wait_for_process(pid_t pid, int *status)
650 {
651 int ret;
652
653 DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
654 for (;;) {
655 fd_set rfds;
656
657 FD_ZERO(&rfds);
658 FD_SET(signal_pipe, &rfds);
659 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
660 if (ret < 0)
661 break;
662 ret = next_signal();
663 if (!ret)
664 continue;
665 if (ret == SIGCHLD) {
666 ret = waitpid(pid, status, 0);
667 if (ret >= 0)
668 break;
669 if (errno != EINTR) { /* error */
670 ret = -ERRNO_TO_DSS_ERROR(errno);
671 break;
672 }
673 }
674 /* SIGINT or SIGTERM */
675 dss_kill(pid, SIGTERM, "killing child process");
676 }
677 if (ret < 0)
678 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
679 else
680 log_termination_msg(pid, *status);
681 return ret;
682 }
683
684 static void handle_pre_remove_exit(int status)
685 {
686 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
687 snapshot_removal_status = HS_READY;
688 gettimeofday(&next_removal_check, NULL);
689 next_removal_check.tv_sec += 60;
690 return;
691 }
692 snapshot_removal_status = HS_PRE_SUCCESS;
693 }
694
695 static int handle_rm_exit(int status)
696 {
697 if (!WIFEXITED(status)) {
698 snapshot_removal_status = HS_READY;
699 return -E_INVOLUNTARY_EXIT;
700 }
701 if (WEXITSTATUS(status)) {
702 snapshot_removal_status = HS_READY;
703 return -E_BAD_EXIT_CODE;
704 }
705 snapshot_removal_status = HS_SUCCESS;
706 return 1;
707 }
708
709 static void handle_post_remove_exit(void)
710 {
711 snapshot_removal_status = HS_READY;
712 }
713
714 static int handle_remove_exit(int status)
715 {
716 int ret;
717 struct snapshot *s = snapshot_currently_being_removed;
718
719 assert(s);
720 switch (snapshot_removal_status) {
721 case HS_PRE_RUNNING:
722 handle_pre_remove_exit(status);
723 ret = 1;
724 break;
725 case HS_RUNNING:
726 ret = handle_rm_exit(status);
727 break;
728 case HS_POST_RUNNING:
729 handle_post_remove_exit();
730 ret = 1;
731 break;
732 default:
733 ret = -E_BUG;
734 }
735 if (snapshot_removal_status == HS_READY) {
736 free(s->name);
737 free(s);
738 snapshot_currently_being_removed = NULL;
739 }
740 remove_pid = 0;
741 return ret;
742 }
743
744 static int wait_for_remove_process(void)
745 {
746 int status, ret;
747
748 assert(remove_pid);
749 assert(
750 snapshot_removal_status == HS_PRE_RUNNING ||
751 snapshot_removal_status == HS_RUNNING ||
752 snapshot_removal_status == HS_POST_RUNNING
753 );
754 ret = wait_for_process(remove_pid, &status);
755 if (ret < 0)
756 return ret;
757 return handle_remove_exit(status);
758 }
759
760 static int handle_rsync_exit(int status)
761 {
762 int es, ret;
763
764 if (!WIFEXITED(status)) {
765 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)create_pid);
766 ret = -E_INVOLUNTARY_EXIT;
767 snapshot_creation_status = HS_READY;
768 goto out;
769 }
770 es = WEXITSTATUS(status);
771 /*
772 * Restart rsync on non-fatal errors:
773 * 12: Error in rsync protocol data stream
774 * 13: Errors with program diagnostics
775 */
776 if (es == 12 || es == 13) {
777 DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
778 (int)create_pid, es);
779 snapshot_creation_status = HS_NEEDS_RESTART;
780 next_snapshot_time = get_current_time() + 60;
781 ret = 1;
782 goto out;
783 }
784 if (es != 0 && es != 23 && es != 24) {
785 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)create_pid, es);
786 ret = -E_BAD_EXIT_CODE;
787 snapshot_creation_status = HS_READY;
788 goto out;
789 }
790 ret = rename_incomplete_snapshot(current_snapshot_creation_time);
791 if (ret < 0)
792 goto out;
793 snapshot_creation_status = HS_SUCCESS;
794 free(name_of_reference_snapshot);
795 name_of_reference_snapshot = NULL;
796 out:
797 create_process_stopped = 0;
798 return ret;
799 }
800
801 static int handle_pre_create_hook_exit(int status)
802 {
803 int es, ret;
804 static int warn_count;
805
806 if (!WIFEXITED(status)) {
807 snapshot_creation_status = HS_READY;
808 ret = -E_INVOLUNTARY_EXIT;
809 goto out;
810 }
811 es = WEXITSTATUS(status);
812 if (es) {
813 if (!warn_count--) {
814 DSS_NOTICE_LOG("pre_create_hook %s returned %d\n",
815 conf.pre_create_hook_arg, es);
816 DSS_NOTICE_LOG("deferring snapshot creation...\n");
817 warn_count = 60; /* warn only once per hour */
818 }
819 next_snapshot_time = get_current_time() + 60;
820 snapshot_creation_status = HS_READY;
821 ret = 0;
822 goto out;
823 }
824 warn_count = 0;
825 snapshot_creation_status = HS_PRE_SUCCESS;
826 ret = 1;
827 out:
828 return ret;
829 }
830
831 static int handle_sigchld(void)
832 {
833 pid_t pid;
834 int status, ret = reap_child(&pid, &status);
835
836 if (ret <= 0)
837 return ret;
838
839 if (pid == create_pid) {
840 switch (snapshot_creation_status) {
841 case HS_PRE_RUNNING:
842 ret = handle_pre_create_hook_exit(status);
843 break;
844 case HS_RUNNING:
845 ret = handle_rsync_exit(status);
846 break;
847 case HS_POST_RUNNING:
848 snapshot_creation_status = HS_READY;
849 ret = 1;
850 break;
851 default:
852 DSS_EMERG_LOG("BUG: create can't die in status %d\n",
853 snapshot_creation_status);
854 return -E_BUG;
855 }
856 create_pid = 0;
857 return ret;
858 }
859 if (pid == remove_pid) {
860 ret = handle_remove_exit(status);
861 if (ret < 0)
862 return ret;
863 return ret;
864 }
865 DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
866 return -E_BUG;
867 }
868
869 static int check_config(void)
870 {
871 if (conf.unit_interval_arg <= 0) {
872 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
873 return -E_INVALID_NUMBER;
874 }
875 DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
876 if (conf.num_intervals_arg <= 0) {
877 DSS_ERROR_LOG("bad number of intervals %i\n", conf.num_intervals_arg);
878 return -E_INVALID_NUMBER;
879 }
880 DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
881 return 1;
882 }
883
884 /*
885 * Returns < 0 on errors, 0 if no config file is given and > 0 if the config
886 * file was read successfully.
887 */
888 static int parse_config_file(int override)
889 {
890 int ret, config_file_exists;
891 char *config_file;
892 struct stat statbuf;
893 char *old_logfile_arg = NULL;
894 int old_daemon_given = 0;
895
896 if (conf.config_file_given)
897 config_file = dss_strdup(conf.config_file_arg);
898 else {
899 char *home = get_homedir();
900 config_file = make_message("%s/.dssrc", home);
901 free(home);
902 }
903 if (override) { /* SIGHUP */
904 if (conf.logfile_given)
905 old_logfile_arg = dss_strdup(conf.logfile_arg);
906 old_daemon_given = conf.daemon_given;
907 }
908
909 config_file_exists = !stat(config_file, &statbuf);
910 if (!config_file_exists && conf.config_file_given) {
911 ret = -ERRNO_TO_DSS_ERROR(errno);
912 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
913 goto out;
914 }
915 if (config_file_exists) {
916 struct cmdline_parser_params params;
917 params.override = override;
918 params.initialize = 0;
919 params.check_required = 1;
920 params.check_ambiguity = 0;
921 params.print_errors = 1;
922 if (override) { /* invalidate all rsync options */
923 int i;
924
925 for (i = 0; i < conf.rsync_option_given; i++) {
926 free(conf.rsync_option_arg[i]);
927 conf.rsync_option_arg[i] = NULL;
928 }
929 conf.rsync_option_given = 0;
930 }
931 cmdline_parser_config_file(config_file, &conf, &params);
932 }
933 ret = check_config();
934 if (ret < 0)
935 goto out;
936 if (override) {
937 /* don't change daemon mode on SIGHUP */
938 conf.daemon_given = old_daemon_given;
939 close_log(logfile);
940 logfile = NULL;
941 if (conf.logfile_given)
942 free(old_logfile_arg);
943 else if (conf.daemon_given) { /* re-use old logfile */
944 conf.logfile_arg = old_logfile_arg;
945 conf.logfile_given = 1;
946 }
947 }
948 if (conf.logfile_given && conf.run_given && conf.daemon_given) {
949 logfile = open_log(conf.logfile_arg);
950 log_welcome(conf.loglevel_arg);
951 }
952 DSS_DEBUG_LOG("loglevel: %d\n", conf.loglevel_arg);
953 ret = config_file_exists;
954 out:
955 free(config_file);
956 if (ret < 0)
957 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
958 return ret;
959 }
960
961 static int change_to_dest_dir(void)
962 {
963 DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
964 return dss_chdir(conf.dest_dir_arg);
965 }
966
967 static int handle_sighup(void)
968 {
969 int ret;
970
971 DSS_NOTICE_LOG("SIGHUP, re-reading config\n");
972 dump_dss_config("old");
973 ret = parse_config_file(1);
974 if (ret < 0)
975 return ret;
976 dump_dss_config("reloaded");
977 invalidate_next_snapshot_time();
978 return change_to_dest_dir();
979 }
980
981 static int handle_signal(void)
982 {
983 int sig, ret = next_signal();
984
985 if (ret <= 0)
986 goto out;
987 sig = ret;
988 switch (sig) {
989 case SIGINT:
990 case SIGTERM:
991 restart_create_process();
992 dss_kill(create_pid, SIGTERM, NULL);
993 dss_kill(remove_pid, SIGTERM, NULL);
994 ret = -E_SIGNAL;
995 break;
996 case SIGHUP:
997 ret = handle_sighup();
998 break;
999 case SIGCHLD:
1000 ret = handle_sigchld();
1001 break;
1002 }
1003 out:
1004 if (ret < 0)
1005 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
1006 return ret;
1007 }
1008
1009 /*
1010 * We can not use rsync locally if the local user is different from the remote
1011 * user or if the src dir is not on the local host (or both).
1012 */
1013 static int use_rsync_locally(char *logname)
1014 {
1015 char *h = conf.remote_host_arg;
1016
1017 if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
1018 return 0;
1019 if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
1020 return 0;
1021 return 1;
1022 }
1023
1024 static int rename_resume_snap(int64_t creation_time)
1025 {
1026 struct snapshot_list sl;
1027 struct snapshot *s = NULL;
1028 char *new_name = incomplete_name(creation_time);
1029 int ret;
1030 const char *why;
1031
1032 sl.num_snapshots = 0;
1033
1034 ret = 0;
1035 if (conf.no_resume_given)
1036 goto out;
1037 dss_get_snapshot_list(&sl);
1038 /*
1039 * Snapshot recycling: We first look at the newest snapshot. If this
1040 * snapshot happens to be incomplete, the last rsync process was
1041 * aborted and we reuse this one. Otherwise we look at snapshots which
1042 * could be removed (outdated and redundant snapshots) as candidates
1043 * for recycling. If no outdated/redundant snapshot exists, we check if
1044 * there is an orphaned snapshot, which likely is useless anyway.
1045 *
1046 * Only if no existing snapshot is suitable for recycling, we bite the
1047 * bullet and create a new one.
1048 */
1049 s = get_newest_snapshot(&sl);
1050 if (!s) /* no snapshots at all */
1051 goto out;
1052 /* re-use last snapshot if it is incomplete */
1053 why = "aborted";
1054 if ((s->flags & SS_COMPLETE) == 0)
1055 goto out;
1056 why = "outdated";
1057 s = find_outdated_snapshot(&sl);
1058 if (s)
1059 goto out;
1060 why = "redundant";
1061 s = find_redundant_snapshot(&sl);
1062 if (s)
1063 goto out;
1064 why = "orphaned";
1065 s = find_orphaned_snapshot(&sl);
1066 out:
1067 if (s) {
1068 DSS_INFO_LOG("reusing %s snapshot %s\n", why, s->name);
1069 ret = dss_rename(s->name, new_name);
1070 }
1071 if (ret >= 0)
1072 DSS_NOTICE_LOG("creating new snapshot %s\n", new_name);
1073 free(new_name);
1074 free_snapshot_list(&sl);
1075 return ret;
1076 }
1077
1078 static void create_rsync_argv(char ***argv, int64_t *num)
1079 {
1080 char *logname;
1081 int i = 0, j;
1082 struct snapshot_list sl;
1083
1084 dss_get_snapshot_list(&sl);
1085 assert(!name_of_reference_snapshot);
1086 name_of_reference_snapshot = name_of_newest_complete_snapshot(&sl);
1087 free_snapshot_list(&sl);
1088
1089 *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
1090 (*argv)[i++] = dss_strdup("rsync");
1091 (*argv)[i++] = dss_strdup("-aq");
1092 (*argv)[i++] = dss_strdup("--delete");
1093 for (j = 0; j < conf.rsync_option_given; j++)
1094 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
1095 if (name_of_reference_snapshot) {
1096 DSS_INFO_LOG("using %s as reference\n", name_of_reference_snapshot);
1097 (*argv)[i++] = make_message("--link-dest=../%s",
1098 name_of_reference_snapshot);
1099 } else
1100 DSS_INFO_LOG("no suitable reference snapshot found\n");
1101 logname = dss_logname();
1102 if (use_rsync_locally(logname))
1103 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
1104 else
1105 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
1106 conf.remote_user_arg : logname,
1107 conf.remote_host_arg, conf.source_dir_arg);
1108 free(logname);
1109 *num = get_current_time();
1110 (*argv)[i++] = incomplete_name(*num);
1111 (*argv)[i++] = NULL;
1112 for (j = 0; j < i; j++)
1113 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
1114 }
1115
1116 static void free_rsync_argv(char **argv)
1117 {
1118 int i;
1119
1120 if (!argv)
1121 return;
1122 for (i = 0; argv[i]; i++)
1123 free(argv[i]);
1124 free(argv);
1125 }
1126
1127 static int create_snapshot(char **argv)
1128 {
1129 int ret;
1130
1131 ret = rename_resume_snap(current_snapshot_creation_time);
1132 if (ret < 0)
1133 return ret;
1134 dss_exec(&create_pid, argv[0], argv);
1135 snapshot_creation_status = HS_RUNNING;
1136 return ret;
1137 }
1138
1139 static int select_loop(void)
1140 {
1141 int ret;
1142 /* check every 60 seconds for free disk space */
1143 struct timeval tv;
1144 char **rsync_argv = NULL;
1145
1146 for (;;) {
1147 fd_set rfds;
1148 struct timeval *tvp;
1149
1150 if (remove_pid)
1151 tvp = NULL; /* sleep until rm hook/process dies */
1152 else { /* sleep one minute */
1153 tv.tv_sec = 60;
1154 tv.tv_usec = 0;
1155 tvp = &tv;
1156 }
1157 FD_ZERO(&rfds);
1158 FD_SET(signal_pipe, &rfds);
1159 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
1160 if (ret < 0)
1161 goto out;
1162 if (FD_ISSET(signal_pipe, &rfds)) {
1163 ret = handle_signal();
1164 if (ret < 0)
1165 goto out;
1166 }
1167 if (remove_pid)
1168 continue;
1169 if (snapshot_removal_status == HS_PRE_SUCCESS) {
1170 ret = exec_rm();
1171 if (ret < 0)
1172 goto out;
1173 continue;
1174 }
1175 if (snapshot_removal_status == HS_SUCCESS) {
1176 post_remove_hook();
1177 continue;
1178 }
1179 ret = try_to_free_disk_space();
1180 if (ret < 0)
1181 goto out;
1182 if (snapshot_removal_status != HS_READY) {
1183 stop_create_process();
1184 continue;
1185 }
1186 restart_create_process();
1187 switch (snapshot_creation_status) {
1188 case HS_READY:
1189 if (!next_snapshot_is_due())
1190 continue;
1191 pre_create_hook();
1192 continue;
1193 case HS_PRE_RUNNING:
1194 case HS_RUNNING:
1195 case HS_POST_RUNNING:
1196 continue;
1197 case HS_PRE_SUCCESS:
1198 if (!name_of_reference_snapshot) {
1199 free_rsync_argv(rsync_argv);
1200 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1201 }
1202 ret = create_snapshot(rsync_argv);
1203 if (ret < 0)
1204 goto out;
1205 continue;
1206 case HS_NEEDS_RESTART:
1207 if (!next_snapshot_is_due())
1208 continue;
1209 ret = create_snapshot(rsync_argv);
1210 if (ret < 0)
1211 goto out;
1212 continue;
1213 case HS_SUCCESS:
1214 post_create_hook();
1215 continue;
1216 }
1217 }
1218 out:
1219 return ret;
1220 }
1221
1222 static void exit_hook(int exit_code)
1223 {
1224 char *argv[3];
1225 pid_t pid;
1226
1227 argv[0] = conf.exit_hook_arg;
1228 argv[1] = dss_strerror(-exit_code);
1229 argv[2] = NULL;
1230
1231 DSS_NOTICE_LOG("executing %s %s\n", argv[0], argv[1]);
1232 dss_exec(&pid, conf.exit_hook_arg, argv);
1233 }
1234
1235 static int com_run(void)
1236 {
1237 int ret;
1238
1239 if (conf.dry_run_given) {
1240 DSS_ERROR_LOG("dry_run not supported by this command\n");
1241 return -E_SYNTAX;
1242 }
1243 ret = install_sighandler(SIGHUP);
1244 if (ret < 0)
1245 return ret;
1246 ret = select_loop();
1247 if (ret >= 0) /* impossible */
1248 ret = -E_BUG;
1249 exit_hook(ret);
1250 return ret;
1251 }
1252
1253 static int com_prune(void)
1254 {
1255 int ret;
1256 struct snapshot_list sl;
1257 struct snapshot *victim;
1258 struct disk_space ds;
1259 const char *why;
1260
1261 ret = get_disk_space(".", &ds);
1262 if (ret < 0)
1263 return ret;
1264 log_disk_space(&ds);
1265 dss_get_snapshot_list(&sl);
1266 why = "outdated";
1267 victim = find_outdated_snapshot(&sl);
1268 if (victim)
1269 goto rm;
1270 why = "redundant";
1271 victim = find_redundant_snapshot(&sl);
1272 if (victim)
1273 goto rm;
1274 ret = 0;
1275 goto out;
1276 rm:
1277 if (conf.dry_run_given) {
1278 dss_msg("%s snapshot %s (interval = %i)\n",
1279 why, victim->name, victim->interval);
1280 ret = 0;
1281 goto out;
1282 }
1283 pre_remove_hook(victim, why);
1284 if (snapshot_removal_status == HS_PRE_RUNNING) {
1285 ret = wait_for_remove_process();
1286 if (ret < 0)
1287 goto out;
1288 if (snapshot_removal_status != HS_PRE_SUCCESS)
1289 goto out;
1290 }
1291 ret = exec_rm();
1292 if (ret < 0)
1293 goto out;
1294 ret = wait_for_remove_process();
1295 if (ret < 0)
1296 goto out;
1297 if (snapshot_removal_status != HS_SUCCESS)
1298 goto out;
1299 post_remove_hook();
1300 if (snapshot_removal_status != HS_POST_RUNNING)
1301 goto out;
1302 ret = wait_for_remove_process();
1303 if (ret < 0)
1304 goto out;
1305 ret = 1;
1306 out:
1307 free_snapshot_list(&sl);
1308 return ret;
1309 }
1310
1311 static int com_create(void)
1312 {
1313 int ret, status;
1314 char **rsync_argv;
1315
1316 if (conf.dry_run_given) {
1317 int i;
1318 char *msg = NULL;
1319 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1320 for (i = 0; rsync_argv[i]; i++) {
1321 char *tmp = msg;
1322 msg = make_message("%s%s%s", tmp? tmp : "",
1323 tmp? " " : "", rsync_argv[i]);
1324 free(tmp);
1325 }
1326 free_rsync_argv(rsync_argv);
1327 dss_msg("%s\n", msg);
1328 free(msg);
1329 return 1;
1330 }
1331 pre_create_hook();
1332 if (create_pid) {
1333 ret = wait_for_process(create_pid, &status);
1334 if (ret < 0)
1335 return ret;
1336 ret = handle_pre_create_hook_exit(status);
1337 if (ret <= 0) /* error, or pre-create failed */
1338 return ret;
1339 }
1340 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1341 ret = create_snapshot(rsync_argv);
1342 if (ret < 0)
1343 goto out;
1344 ret = wait_for_process(create_pid, &status);
1345 if (ret < 0)
1346 goto out;
1347 ret = handle_rsync_exit(status);
1348 if (ret < 0)
1349 goto out;
1350 post_create_hook();
1351 if (create_pid)
1352 ret = wait_for_process(create_pid, &status);
1353 out:
1354 free_rsync_argv(rsync_argv);
1355 return ret;
1356 }
1357
1358 static int com_ls(void)
1359 {
1360 int i;
1361 struct snapshot_list sl;
1362 struct snapshot *s;
1363
1364 dss_get_snapshot_list(&sl);
1365 FOR_EACH_SNAPSHOT(s, i, &sl) {
1366 int64_t d = 0;
1367 if (s->flags & SS_COMPLETE)
1368 d = (s->completion_time - s->creation_time) / 60;
1369 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1370 };
1371 free_snapshot_list(&sl);
1372 return 1;
1373 }
1374
1375 static int setup_signal_handling(void)
1376 {
1377 int ret;
1378
1379 DSS_INFO_LOG("setting up signal handlers\n");
1380 signal_pipe = signal_init(); /* always successful */
1381 ret = install_sighandler(SIGINT);
1382 if (ret < 0)
1383 return ret;
1384 ret = install_sighandler(SIGTERM);
1385 if (ret < 0)
1386 return ret;
1387 return install_sighandler(SIGCHLD);
1388 }
1389
1390 /**
1391 * The main function of dss.
1392 *
1393 * \param argc Usual argument count.
1394 * \param argv Usual argument vector.
1395 */
1396 int main(int argc, char **argv)
1397 {
1398 int ret;
1399 struct cmdline_parser_params params;
1400
1401 params.override = 0;
1402 params.initialize = 1;
1403 params.check_required = 0;
1404 params.check_ambiguity = 0;
1405 params.print_errors = 1;
1406
1407 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1408 ret = parse_config_file(0);
1409 if (ret < 0)
1410 goto out;
1411 if (ret == 0) { /* no config file given */
1412 /*
1413 * Parse the command line options again, but this time check
1414 * that all required options are given.
1415 */
1416 struct cmdline_parser_params params;
1417 params.override = 1;
1418 params.initialize = 1;
1419 params.check_required = 1;
1420 params.check_ambiguity = 1;
1421 params.print_errors = 1;
1422 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1423 }
1424 if (conf.daemon_given)
1425 daemon_init();
1426 ret = change_to_dest_dir();
1427 if (ret < 0)
1428 goto out;
1429 dump_dss_config("startup");
1430 ret = setup_signal_handling();
1431 if (ret < 0)
1432 goto out;
1433 ret = call_command_handler();
1434 out:
1435 if (ret < 0)
1436 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1437 exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1438 }