Simplify exec functions.
[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 const *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[] = {"rm", "-rf", new_name, NULL};
328 int ret;
329
330 assert(snapshot_removal_status == HS_PRE_SUCCESS);
331 assert(remove_pid == 0);
332
333 DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
334 ret = dss_rename(s->name, new_name);
335 if (ret < 0)
336 goto out;
337 dss_exec(&remove_pid, argv[0], argv);
338 snapshot_removal_status = HS_RUNNING;
339 out:
340 free(new_name);
341 return ret;
342 }
343
344 static int snapshot_is_being_created(struct snapshot *s)
345 {
346 return s->creation_time == current_snapshot_creation_time;
347 }
348
349 static struct snapshot *find_orphaned_snapshot(struct snapshot_list *sl)
350 {
351 struct snapshot *s;
352 int i;
353
354 DSS_DEBUG_LOG("looking for orphaned snapshots\n");
355 FOR_EACH_SNAPSHOT(s, i, sl) {
356 if (snapshot_is_being_created(s))
357 continue;
358 /*
359 * We know that no rm is currently running, so if s is marked
360 * as being deleted, a previously started rm must have failed.
361 */
362 if (s->flags & SS_BEING_DELETED)
363 return s;
364
365 if (s->flags & SS_COMPLETE) /* good snapshot */
366 continue;
367 /*
368 * This snapshot is incomplete and it is not the snapshot
369 * currently being created. However, we must not remove it if
370 * rsync is about to be restarted. As only the newest snapshot
371 * can be restarted, this snapshot is orphaned if it is not the
372 * newest snapshot or if we are not about to restart rsync.
373 */
374 if (get_newest_snapshot(sl) != s)
375 return s;
376 if (snapshot_creation_status != HS_NEEDS_RESTART)
377 return s;
378 }
379 /* no orphaned snapshots */
380 return NULL;
381 }
382
383 static int is_reference_snapshot(struct snapshot *s)
384 {
385 if (!name_of_reference_snapshot)
386 return 0;
387 return strcmp(s->name, name_of_reference_snapshot)? 0 : 1;
388 }
389
390 /*
391 * return: 0: no redundant snapshots, 1: rm process started, negative: error
392 */
393 static struct snapshot *find_redundant_snapshot(struct snapshot_list *sl)
394 {
395 int i, interval;
396 struct snapshot *s;
397 unsigned missing = 0;
398
399 DSS_DEBUG_LOG("looking for intervals containing too many snapshots\n");
400 for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
401 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
402 unsigned num = sl->interval_count[interval];
403 struct snapshot *victim = NULL, *prev = NULL;
404 int64_t score = LONG_MAX;
405
406 if (keep >= num)
407 missing += keep - num;
408 // DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
409 // interval, keep, num, missing);
410 if (keep + missing >= num)
411 continue;
412 /* redundant snapshot in this interval, pick snapshot with lowest score */
413 FOR_EACH_SNAPSHOT(s, i, sl) {
414 int64_t this_score;
415
416 if (snapshot_is_being_created(s))
417 continue;
418 if (is_reference_snapshot(s))
419 continue;
420 //DSS_DEBUG_LOG("checking %s\n", s->name);
421 if (s->interval > interval) {
422 prev = s;
423 continue;
424 }
425 if (s->interval < interval)
426 break;
427 if (!victim) {
428 victim = s;
429 prev = s;
430 continue;
431 }
432 assert(prev);
433 /* check if s is a better victim */
434 this_score = s->creation_time - prev->creation_time;
435 assert(this_score >= 0);
436 //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
437 if (this_score < score) {
438 score = this_score;
439 victim = s;
440 }
441 prev = s;
442 }
443 assert(victim);
444 return victim;
445 }
446 return NULL;
447 }
448
449 static struct snapshot *find_outdated_snapshot(struct snapshot_list *sl)
450 {
451 int i;
452 struct snapshot *s;
453
454 DSS_DEBUG_LOG("looking for snapshots belonging to intervals >= %d\n",
455 conf.num_intervals_arg);
456 FOR_EACH_SNAPSHOT(s, i, sl) {
457 if (snapshot_is_being_created(s))
458 continue;
459 if (is_reference_snapshot(s))
460 continue;
461 if (s->interval < conf.num_intervals_arg)
462 continue;
463 return s;
464 }
465 return NULL;
466 }
467
468 struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
469 {
470 int i;
471 struct snapshot *s;
472 FOR_EACH_SNAPSHOT(s, i, sl) {
473 if (snapshot_is_being_created(s))
474 continue;
475 if (is_reference_snapshot(s))
476 continue;
477 DSS_INFO_LOG("oldest removable snapshot: %s\n", s->name);
478 return s;
479 }
480 return NULL;
481 }
482
483 static int rename_incomplete_snapshot(int64_t start)
484 {
485 char *old_name;
486 int ret;
487
488 free(path_to_last_complete_snapshot);
489 ret = complete_name(start, get_current_time(),
490 &path_to_last_complete_snapshot);
491 if (ret < 0)
492 return ret;
493 old_name = incomplete_name(start);
494 ret = dss_rename(old_name, path_to_last_complete_snapshot);
495 if (ret >= 0)
496 DSS_NOTICE_LOG("%s -> %s\n", old_name,
497 path_to_last_complete_snapshot);
498 free(old_name);
499 return ret;
500 }
501
502 static int try_to_free_disk_space(void)
503 {
504 int ret;
505 struct snapshot_list sl;
506 struct snapshot *victim;
507 struct timeval now;
508 const char *why;
509 int low_disk_space;
510
511 ret = disk_space_low(NULL);
512 if (ret < 0)
513 return ret;
514 low_disk_space = ret;
515 gettimeofday(&now, NULL);
516 if (tv_diff(&next_removal_check, &now, NULL) > 0)
517 return 0;
518 if (!low_disk_space) {
519 if (conf.keep_redundant_given)
520 return 0;
521 if (snapshot_creation_status != HS_READY)
522 return 0;
523 if (next_snapshot_is_due())
524 return 0;
525 }
526 dss_get_snapshot_list(&sl);
527 ret = 0;
528 if (!low_disk_space && sl.num_snapshots <= 1)
529 goto out;
530 why = "outdated";
531 victim = find_outdated_snapshot(&sl);
532 if (victim)
533 goto remove;
534 why = "redundant";
535 victim = find_redundant_snapshot(&sl);
536 if (victim)
537 goto remove;
538 /* try harder only if disk space is low */
539 if (!low_disk_space)
540 goto out;
541 why = "orphaned";
542 victim = find_orphaned_snapshot(&sl);
543 if (victim)
544 goto remove;
545 DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
546 victim = find_oldest_removable_snapshot(&sl);
547 if (victim)
548 goto remove;
549 DSS_CRIT_LOG("uhuhu: disk space low and nothing to remove\n");
550 ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
551 goto out;
552 remove:
553 pre_remove_hook(victim, why);
554 out:
555 free_snapshot_list(&sl);
556 return ret;
557 }
558
559 static void post_create_hook(void)
560 {
561 char *cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
562 conf.dest_dir_arg, path_to_last_complete_snapshot);
563 DSS_NOTICE_LOG("executing %s\n", cmd);
564 dss_exec_cmdline_pid(&create_pid, cmd);
565 free(cmd);
566 snapshot_creation_status = HS_POST_RUNNING;
567 }
568
569 static void post_remove_hook(void)
570 {
571 char *cmd;
572 struct snapshot *s = snapshot_currently_being_removed;
573
574 assert(s);
575
576 cmd = make_message("%s %s/%s", conf.post_remove_hook_arg,
577 conf.dest_dir_arg, s->name);
578 DSS_NOTICE_LOG("executing %s\n", cmd);
579 dss_exec_cmdline_pid(&remove_pid, cmd);
580 free(cmd);
581 snapshot_removal_status = HS_POST_RUNNING;
582 }
583
584 static void dss_kill(pid_t pid, int sig, const char *msg)
585 {
586 const char *signame, *process_name;
587
588 if (pid == 0)
589 return;
590 switch (sig) {
591 case SIGTERM: signame = "TERM"; break;
592 case SIGSTOP: signame = "STOP"; break;
593 case SIGCONT: signame = "CONT"; break;
594 default: signame = "????";
595 }
596
597 if (pid == create_pid)
598 process_name = "create";
599 else if (pid == remove_pid)
600 process_name = "remove";
601 else process_name = "??????";
602
603 if (msg)
604 DSS_INFO_LOG("%s\n", msg);
605 DSS_DEBUG_LOG("sending signal %d (%s) to pid %d (%s process)\n",
606 sig, signame, (int)pid, process_name);
607 if (kill(pid, sig) >= 0)
608 return;
609 DSS_INFO_LOG("failed to send signal %d (%s) to pid %d (%s process)\n",
610 sig, signame, (int)pid, process_name);
611 }
612
613 static void stop_create_process(void)
614 {
615 if (create_process_stopped)
616 return;
617 dss_kill(create_pid, SIGSTOP, "suspending create process");
618 create_process_stopped = 1;
619 }
620
621 static void restart_create_process(void)
622 {
623 if (!create_process_stopped)
624 return;
625 dss_kill(create_pid, SIGCONT, "resuming create process");
626 create_process_stopped = 0;
627 }
628
629 /**
630 * Print a log message about the exit status of a child.
631 */
632 static void log_termination_msg(pid_t pid, int status)
633 {
634 if (WIFEXITED(status))
635 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
636 WEXITSTATUS(status));
637 else if (WIFSIGNALED(status))
638 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
639 WTERMSIG(status));
640 else
641 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
642 }
643
644 static int wait_for_process(pid_t pid, int *status)
645 {
646 int ret;
647
648 DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
649 for (;;) {
650 fd_set rfds;
651
652 FD_ZERO(&rfds);
653 FD_SET(signal_pipe, &rfds);
654 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
655 if (ret < 0)
656 break;
657 ret = next_signal();
658 if (!ret)
659 continue;
660 if (ret == SIGCHLD) {
661 ret = waitpid(pid, status, 0);
662 if (ret >= 0)
663 break;
664 if (errno != EINTR) { /* error */
665 ret = -ERRNO_TO_DSS_ERROR(errno);
666 break;
667 }
668 }
669 /* SIGINT or SIGTERM */
670 dss_kill(pid, SIGTERM, "killing child process");
671 }
672 if (ret < 0)
673 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
674 else
675 log_termination_msg(pid, *status);
676 return ret;
677 }
678
679 static void handle_pre_remove_exit(int status)
680 {
681 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
682 snapshot_removal_status = HS_READY;
683 gettimeofday(&next_removal_check, NULL);
684 next_removal_check.tv_sec += 60;
685 return;
686 }
687 snapshot_removal_status = HS_PRE_SUCCESS;
688 }
689
690 static int handle_rm_exit(int status)
691 {
692 if (!WIFEXITED(status)) {
693 snapshot_removal_status = HS_READY;
694 return -E_INVOLUNTARY_EXIT;
695 }
696 if (WEXITSTATUS(status)) {
697 snapshot_removal_status = HS_READY;
698 return -E_BAD_EXIT_CODE;
699 }
700 snapshot_removal_status = HS_SUCCESS;
701 return 1;
702 }
703
704 static void handle_post_remove_exit(void)
705 {
706 snapshot_removal_status = HS_READY;
707 }
708
709 static int handle_remove_exit(int status)
710 {
711 int ret;
712 struct snapshot *s = snapshot_currently_being_removed;
713
714 assert(s);
715 switch (snapshot_removal_status) {
716 case HS_PRE_RUNNING:
717 handle_pre_remove_exit(status);
718 ret = 1;
719 break;
720 case HS_RUNNING:
721 ret = handle_rm_exit(status);
722 break;
723 case HS_POST_RUNNING:
724 handle_post_remove_exit();
725 ret = 1;
726 break;
727 default:
728 ret = -E_BUG;
729 }
730 if (snapshot_removal_status == HS_READY) {
731 free(s->name);
732 free(s);
733 snapshot_currently_being_removed = NULL;
734 }
735 remove_pid = 0;
736 return ret;
737 }
738
739 static int wait_for_remove_process(void)
740 {
741 int status, ret;
742
743 assert(remove_pid);
744 assert(
745 snapshot_removal_status == HS_PRE_RUNNING ||
746 snapshot_removal_status == HS_RUNNING ||
747 snapshot_removal_status == HS_POST_RUNNING
748 );
749 ret = wait_for_process(remove_pid, &status);
750 if (ret < 0)
751 return ret;
752 return handle_remove_exit(status);
753 }
754
755 static int handle_rsync_exit(int status)
756 {
757 int es, ret;
758
759 if (!WIFEXITED(status)) {
760 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)create_pid);
761 ret = -E_INVOLUNTARY_EXIT;
762 snapshot_creation_status = HS_READY;
763 goto out;
764 }
765 es = WEXITSTATUS(status);
766 /*
767 * Restart rsync on non-fatal errors:
768 * 12: Error in rsync protocol data stream
769 * 13: Errors with program diagnostics
770 */
771 if (es == 12 || es == 13) {
772 DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
773 (int)create_pid, es);
774 snapshot_creation_status = HS_NEEDS_RESTART;
775 next_snapshot_time = get_current_time() + 60;
776 ret = 1;
777 goto out;
778 }
779 if (es != 0 && es != 23 && es != 24) {
780 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)create_pid, es);
781 ret = -E_BAD_EXIT_CODE;
782 snapshot_creation_status = HS_READY;
783 goto out;
784 }
785 ret = rename_incomplete_snapshot(current_snapshot_creation_time);
786 if (ret < 0)
787 goto out;
788 snapshot_creation_status = HS_SUCCESS;
789 free(name_of_reference_snapshot);
790 name_of_reference_snapshot = NULL;
791 out:
792 create_process_stopped = 0;
793 return ret;
794 }
795
796 static int handle_pre_create_hook_exit(int status)
797 {
798 int es, ret;
799 static int warn_count;
800
801 if (!WIFEXITED(status)) {
802 snapshot_creation_status = HS_READY;
803 ret = -E_INVOLUNTARY_EXIT;
804 goto out;
805 }
806 es = WEXITSTATUS(status);
807 if (es) {
808 if (!warn_count--) {
809 DSS_NOTICE_LOG("pre_create_hook %s returned %d\n",
810 conf.pre_create_hook_arg, es);
811 DSS_NOTICE_LOG("deferring snapshot creation...\n");
812 warn_count = 60; /* warn only once per hour */
813 }
814 next_snapshot_time = get_current_time() + 60;
815 snapshot_creation_status = HS_READY;
816 ret = 0;
817 goto out;
818 }
819 warn_count = 0;
820 snapshot_creation_status = HS_PRE_SUCCESS;
821 ret = 1;
822 out:
823 return ret;
824 }
825
826 static int handle_sigchld(void)
827 {
828 pid_t pid;
829 int status, ret = reap_child(&pid, &status);
830
831 if (ret <= 0)
832 return ret;
833
834 if (pid == create_pid) {
835 switch (snapshot_creation_status) {
836 case HS_PRE_RUNNING:
837 ret = handle_pre_create_hook_exit(status);
838 break;
839 case HS_RUNNING:
840 ret = handle_rsync_exit(status);
841 break;
842 case HS_POST_RUNNING:
843 snapshot_creation_status = HS_READY;
844 ret = 1;
845 break;
846 default:
847 DSS_EMERG_LOG("BUG: create can't die in status %d\n",
848 snapshot_creation_status);
849 return -E_BUG;
850 }
851 create_pid = 0;
852 return ret;
853 }
854 if (pid == remove_pid) {
855 ret = handle_remove_exit(status);
856 if (ret < 0)
857 return ret;
858 return ret;
859 }
860 DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
861 return -E_BUG;
862 }
863
864 static int check_config(void)
865 {
866 if (conf.unit_interval_arg <= 0) {
867 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
868 return -E_INVALID_NUMBER;
869 }
870 DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
871 if (conf.num_intervals_arg <= 0) {
872 DSS_ERROR_LOG("bad number of intervals %i\n", conf.num_intervals_arg);
873 return -E_INVALID_NUMBER;
874 }
875 DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
876 return 1;
877 }
878
879 /*
880 * Returns < 0 on errors, 0 if no config file is given and > 0 if the config
881 * file was read successfully.
882 */
883 static int parse_config_file(int override)
884 {
885 int ret, config_file_exists;
886 char *config_file;
887 struct stat statbuf;
888 char *old_logfile_arg = NULL;
889 int old_daemon_given = 0;
890
891 if (conf.config_file_given)
892 config_file = dss_strdup(conf.config_file_arg);
893 else {
894 char *home = get_homedir();
895 config_file = make_message("%s/.dssrc", home);
896 free(home);
897 }
898 if (override) { /* SIGHUP */
899 if (conf.logfile_given)
900 old_logfile_arg = dss_strdup(conf.logfile_arg);
901 old_daemon_given = conf.daemon_given;
902 }
903
904 config_file_exists = !stat(config_file, &statbuf);
905 if (!config_file_exists && conf.config_file_given) {
906 ret = -ERRNO_TO_DSS_ERROR(errno);
907 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
908 goto out;
909 }
910 if (config_file_exists) {
911 struct cmdline_parser_params params = {
912 .override = override,
913 .initialize = 0,
914 .check_required = 1,
915 .check_ambiguity = 0,
916 .print_errors = 1
917 };
918 if (override) { /* invalidate all rsync options */
919 int i;
920
921 for (i = 0; i < conf.rsync_option_given; i++) {
922 free(conf.rsync_option_arg[i]);
923 conf.rsync_option_arg[i] = NULL;
924 }
925 conf.rsync_option_given = 0;
926 }
927 cmdline_parser_config_file(config_file, &conf, &params);
928 }
929 ret = check_config();
930 if (ret < 0)
931 goto out;
932 if (override) {
933 /* don't change daemon mode on SIGHUP */
934 conf.daemon_given = old_daemon_given;
935 close_log(logfile);
936 logfile = NULL;
937 if (conf.logfile_given)
938 free(old_logfile_arg);
939 else if (conf.daemon_given) { /* re-use old logfile */
940 conf.logfile_arg = old_logfile_arg;
941 conf.logfile_given = 1;
942 }
943 }
944 if (conf.logfile_given && conf.run_given && conf.daemon_given) {
945 logfile = open_log(conf.logfile_arg);
946 log_welcome(conf.loglevel_arg);
947 }
948 DSS_DEBUG_LOG("loglevel: %d\n", conf.loglevel_arg);
949 ret = config_file_exists;
950 out:
951 free(config_file);
952 if (ret < 0)
953 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
954 return ret;
955 }
956
957 static int change_to_dest_dir(void)
958 {
959 DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
960 return dss_chdir(conf.dest_dir_arg);
961 }
962
963 static int handle_sighup(void)
964 {
965 int ret;
966
967 DSS_NOTICE_LOG("SIGHUP, re-reading config\n");
968 dump_dss_config("old");
969 ret = parse_config_file(1);
970 if (ret < 0)
971 return ret;
972 dump_dss_config("reloaded");
973 invalidate_next_snapshot_time();
974 return change_to_dest_dir();
975 }
976
977 static int handle_signal(void)
978 {
979 int sig, ret = next_signal();
980
981 if (ret <= 0)
982 goto out;
983 sig = ret;
984 switch (sig) {
985 case SIGINT:
986 case SIGTERM:
987 restart_create_process();
988 dss_kill(create_pid, SIGTERM, NULL);
989 dss_kill(remove_pid, SIGTERM, NULL);
990 ret = -E_SIGNAL;
991 break;
992 case SIGHUP:
993 ret = handle_sighup();
994 break;
995 case SIGCHLD:
996 ret = handle_sigchld();
997 break;
998 }
999 out:
1000 if (ret < 0)
1001 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
1002 return ret;
1003 }
1004
1005 /*
1006 * We can not use rsync locally if the local user is different from the remote
1007 * user or if the src dir is not on the local host (or both).
1008 */
1009 static int use_rsync_locally(char *logname)
1010 {
1011 char *h = conf.remote_host_arg;
1012
1013 if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
1014 return 0;
1015 if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
1016 return 0;
1017 return 1;
1018 }
1019
1020 static int rename_resume_snap(int64_t creation_time)
1021 {
1022 struct snapshot_list sl = {.num_snapshots = 0};
1023 struct snapshot *s = NULL;
1024 char *new_name = incomplete_name(creation_time);
1025 int ret;
1026 const char *why;
1027
1028 ret = 0;
1029 if (conf.no_resume_given)
1030 goto out;
1031 dss_get_snapshot_list(&sl);
1032 /*
1033 * Snapshot recycling: We first look at the newest snapshot. If this
1034 * snapshot happens to be incomplete, the last rsync process was
1035 * aborted and we reuse this one. Otherwise we look at snapshots which
1036 * could be removed (outdated and redundant snapshots) as candidates
1037 * for recycling. If no outdated/redundant snapshot exists, we check if
1038 * there is an orphaned snapshot, which likely is useless anyway.
1039 *
1040 * Only if no existing snapshot is suitable for recycling, we bite the
1041 * bullet and create a new one.
1042 */
1043 s = get_newest_snapshot(&sl);
1044 if (!s) /* no snapshots at all */
1045 goto out;
1046 /* re-use last snapshot if it is incomplete */
1047 why = "aborted";
1048 if ((s->flags & SS_COMPLETE) == 0)
1049 goto out;
1050 why = "outdated";
1051 s = find_outdated_snapshot(&sl);
1052 if (s)
1053 goto out;
1054 why = "redundant";
1055 s = find_redundant_snapshot(&sl);
1056 if (s)
1057 goto out;
1058 why = "orphaned";
1059 s = find_orphaned_snapshot(&sl);
1060 out:
1061 if (s) {
1062 DSS_INFO_LOG("reusing %s snapshot %s\n", why, s->name);
1063 ret = dss_rename(s->name, new_name);
1064 }
1065 if (ret >= 0)
1066 DSS_NOTICE_LOG("creating new snapshot %s\n", new_name);
1067 free(new_name);
1068 free_snapshot_list(&sl);
1069 return ret;
1070 }
1071
1072 static void create_rsync_argv(char ***argv, int64_t *num)
1073 {
1074 char *logname;
1075 int i = 0, j;
1076 struct snapshot_list sl;
1077
1078 dss_get_snapshot_list(&sl);
1079 assert(!name_of_reference_snapshot);
1080 name_of_reference_snapshot = name_of_newest_complete_snapshot(&sl);
1081 free_snapshot_list(&sl);
1082
1083 *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
1084 (*argv)[i++] = dss_strdup("rsync");
1085 (*argv)[i++] = dss_strdup("-aq");
1086 (*argv)[i++] = dss_strdup("--delete");
1087 for (j = 0; j < conf.rsync_option_given; j++)
1088 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
1089 if (name_of_reference_snapshot) {
1090 DSS_INFO_LOG("using %s as reference\n", name_of_reference_snapshot);
1091 (*argv)[i++] = make_message("--link-dest=../%s",
1092 name_of_reference_snapshot);
1093 } else
1094 DSS_INFO_LOG("no suitable reference snapshot found\n");
1095 logname = dss_logname();
1096 if (use_rsync_locally(logname))
1097 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
1098 else
1099 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
1100 conf.remote_user_arg : logname,
1101 conf.remote_host_arg, conf.source_dir_arg);
1102 free(logname);
1103 *num = get_current_time();
1104 (*argv)[i++] = incomplete_name(*num);
1105 (*argv)[i++] = NULL;
1106 for (j = 0; j < i; j++)
1107 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
1108 }
1109
1110 static void free_rsync_argv(char **argv)
1111 {
1112 int i;
1113
1114 if (!argv)
1115 return;
1116 for (i = 0; argv[i]; i++)
1117 free(argv[i]);
1118 free(argv);
1119 }
1120
1121 static int create_snapshot(char **argv)
1122 {
1123 int ret;
1124
1125 ret = rename_resume_snap(current_snapshot_creation_time);
1126 if (ret < 0)
1127 return ret;
1128 dss_exec(&create_pid, argv[0], argv);
1129 snapshot_creation_status = HS_RUNNING;
1130 return ret;
1131 }
1132
1133 static int select_loop(void)
1134 {
1135 int ret;
1136 /* check every 60 seconds for free disk space */
1137 struct timeval tv;
1138 char **rsync_argv = NULL;
1139
1140 for (;;) {
1141 fd_set rfds;
1142 struct timeval *tvp;
1143
1144 if (remove_pid)
1145 tvp = NULL; /* sleep until rm hook/process dies */
1146 else { /* sleep one minute */
1147 tv.tv_sec = 60;
1148 tv.tv_usec = 0;
1149 tvp = &tv;
1150 }
1151 FD_ZERO(&rfds);
1152 FD_SET(signal_pipe, &rfds);
1153 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
1154 if (ret < 0)
1155 goto out;
1156 if (FD_ISSET(signal_pipe, &rfds)) {
1157 ret = handle_signal();
1158 if (ret < 0)
1159 goto out;
1160 }
1161 if (remove_pid)
1162 continue;
1163 if (snapshot_removal_status == HS_PRE_SUCCESS) {
1164 ret = exec_rm();
1165 if (ret < 0)
1166 goto out;
1167 continue;
1168 }
1169 if (snapshot_removal_status == HS_SUCCESS) {
1170 post_remove_hook();
1171 continue;
1172 }
1173 ret = try_to_free_disk_space();
1174 if (ret < 0)
1175 goto out;
1176 if (snapshot_removal_status != HS_READY) {
1177 stop_create_process();
1178 continue;
1179 }
1180 restart_create_process();
1181 switch (snapshot_creation_status) {
1182 case HS_READY:
1183 if (!next_snapshot_is_due())
1184 continue;
1185 pre_create_hook();
1186 continue;
1187 case HS_PRE_RUNNING:
1188 case HS_RUNNING:
1189 case HS_POST_RUNNING:
1190 continue;
1191 case HS_PRE_SUCCESS:
1192 if (!name_of_reference_snapshot) {
1193 free_rsync_argv(rsync_argv);
1194 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1195 }
1196 ret = create_snapshot(rsync_argv);
1197 if (ret < 0)
1198 goto out;
1199 continue;
1200 case HS_NEEDS_RESTART:
1201 if (!next_snapshot_is_due())
1202 continue;
1203 ret = create_snapshot(rsync_argv);
1204 if (ret < 0)
1205 goto out;
1206 continue;
1207 case HS_SUCCESS:
1208 post_create_hook();
1209 continue;
1210 }
1211 }
1212 out:
1213 return ret;
1214 }
1215
1216 static void exit_hook(int exit_code)
1217 {
1218 char *argv[] = {conf.exit_hook_arg, dss_strerror(-exit_code), NULL};
1219 pid_t pid;
1220
1221 DSS_NOTICE_LOG("executing %s %s\n", argv[0], argv[1]);
1222 dss_exec(&pid, conf.exit_hook_arg, argv);
1223 }
1224
1225 static int com_run(void)
1226 {
1227 int ret;
1228
1229 if (conf.dry_run_given) {
1230 DSS_ERROR_LOG("dry_run not supported by this command\n");
1231 return -E_SYNTAX;
1232 }
1233 ret = install_sighandler(SIGHUP);
1234 if (ret < 0)
1235 return ret;
1236 ret = select_loop();
1237 if (ret >= 0) /* impossible */
1238 ret = -E_BUG;
1239 exit_hook(ret);
1240 return ret;
1241 }
1242
1243 static int com_prune(void)
1244 {
1245 int ret;
1246 struct snapshot_list sl;
1247 struct snapshot *victim;
1248 struct disk_space ds;
1249 const char *why;
1250
1251 ret = get_disk_space(".", &ds);
1252 if (ret < 0)
1253 return ret;
1254 log_disk_space(&ds);
1255 dss_get_snapshot_list(&sl);
1256 why = "outdated";
1257 victim = find_outdated_snapshot(&sl);
1258 if (victim)
1259 goto rm;
1260 why = "redundant";
1261 victim = find_redundant_snapshot(&sl);
1262 if (victim)
1263 goto rm;
1264 ret = 0;
1265 goto out;
1266 rm:
1267 if (conf.dry_run_given) {
1268 dss_msg("%s snapshot %s (interval = %i)\n",
1269 why, victim->name, victim->interval);
1270 ret = 0;
1271 goto out;
1272 }
1273 pre_remove_hook(victim, why);
1274 if (snapshot_removal_status == HS_PRE_RUNNING) {
1275 ret = wait_for_remove_process();
1276 if (ret < 0)
1277 goto out;
1278 if (snapshot_removal_status != HS_PRE_SUCCESS)
1279 goto out;
1280 }
1281 ret = exec_rm();
1282 if (ret < 0)
1283 goto out;
1284 ret = wait_for_remove_process();
1285 if (ret < 0)
1286 goto out;
1287 if (snapshot_removal_status != HS_SUCCESS)
1288 goto out;
1289 post_remove_hook();
1290 if (snapshot_removal_status != HS_POST_RUNNING)
1291 goto out;
1292 ret = wait_for_remove_process();
1293 if (ret < 0)
1294 goto out;
1295 ret = 1;
1296 out:
1297 free_snapshot_list(&sl);
1298 return ret;
1299 }
1300
1301 static int com_create(void)
1302 {
1303 int ret, status;
1304 char **rsync_argv;
1305
1306 if (conf.dry_run_given) {
1307 int i;
1308 char *msg = NULL;
1309 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1310 for (i = 0; rsync_argv[i]; i++) {
1311 char *tmp = msg;
1312 msg = make_message("%s%s%s", tmp? tmp : "",
1313 tmp? " " : "", rsync_argv[i]);
1314 free(tmp);
1315 }
1316 free_rsync_argv(rsync_argv);
1317 dss_msg("%s\n", msg);
1318 free(msg);
1319 return 1;
1320 }
1321 pre_create_hook();
1322 if (create_pid) {
1323 ret = wait_for_process(create_pid, &status);
1324 if (ret < 0)
1325 return ret;
1326 ret = handle_pre_create_hook_exit(status);
1327 if (ret <= 0) /* error, or pre-create failed */
1328 return ret;
1329 }
1330 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1331 ret = create_snapshot(rsync_argv);
1332 if (ret < 0)
1333 goto out;
1334 ret = wait_for_process(create_pid, &status);
1335 if (ret < 0)
1336 goto out;
1337 ret = handle_rsync_exit(status);
1338 if (ret < 0)
1339 goto out;
1340 post_create_hook();
1341 if (create_pid)
1342 ret = wait_for_process(create_pid, &status);
1343 out:
1344 free_rsync_argv(rsync_argv);
1345 return ret;
1346 }
1347
1348 static int com_ls(void)
1349 {
1350 int i;
1351 struct snapshot_list sl;
1352 struct snapshot *s;
1353
1354 dss_get_snapshot_list(&sl);
1355 FOR_EACH_SNAPSHOT(s, i, &sl) {
1356 int64_t d = 0;
1357 if (s->flags & SS_COMPLETE)
1358 d = (s->completion_time - s->creation_time) / 60;
1359 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1360 };
1361 free_snapshot_list(&sl);
1362 return 1;
1363 }
1364
1365 static int setup_signal_handling(void)
1366 {
1367 int ret;
1368
1369 DSS_INFO_LOG("setting up signal handlers\n");
1370 signal_pipe = signal_init(); /* always successful */
1371 ret = install_sighandler(SIGINT);
1372 if (ret < 0)
1373 return ret;
1374 ret = install_sighandler(SIGTERM);
1375 if (ret < 0)
1376 return ret;
1377 return install_sighandler(SIGCHLD);
1378 }
1379
1380 /**
1381 * The main function of dss.
1382 *
1383 * \param argc Usual argument count.
1384 * \param argv Usual argument vector.
1385 */
1386 int main(int argc, char **argv)
1387 {
1388 int ret;
1389 struct cmdline_parser_params params = {
1390 .override = 0,
1391 .initialize = 1,
1392 .check_required = 0,
1393 .check_ambiguity = 0,
1394 .print_errors = 1
1395 };
1396
1397 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1398 ret = parse_config_file(0);
1399 if (ret < 0)
1400 goto out;
1401 if (ret == 0) { /* no config file given */
1402 /*
1403 * Parse the command line options again, but this time check
1404 * that all required options are given.
1405 */
1406 params = (struct cmdline_parser_params) {
1407 .override = 1,
1408 .initialize = 1,
1409 .check_required = 1,
1410 .check_ambiguity = 1,
1411 .print_errors = 1
1412 };
1413 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1414 }
1415 if (conf.daemon_given)
1416 daemon_init();
1417 ret = change_to_dest_dir();
1418 if (ret < 0)
1419 goto out;
1420 dump_dss_config("startup");
1421 ret = setup_signal_handling();
1422 if (ret < 0)
1423 goto out;
1424 ret = call_command_handler();
1425 out:
1426 if (ret < 0)
1427 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1428 exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1429 }