dss.c

   1 /*
   2  * Copyright (C) 2008-2011 Andre Noll <maan@tuebingen.mpg.de>
   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 "str.h"
  28 #include "err.h"
  29 #include "file.h"
  30 #include "exec.h"
  31 #include "daemon.h"
  32 #include "sig.h"
  33 #include "df.h"
  34 #include "tv.h"
  35 #include "snap.h"
  36 #include "ipc.h"
  37
  38 /** Command line and config file options. */
  39 static struct gengetopt_args_info conf;
  40 /** Non-NULL if we log to a file. */
  41 static FILE *logfile;
  42 /** The read end of the signal pipe */
  43 static int signal_pipe;
  44 /** Process id of current pre-create-hook/rsync/post-create-hook process. */
  45 static pid_t create_pid;
  46 /** Whether the pre-create-hook/rsync/post-create-hook is currently stopped. */
  47 static int create_process_stopped;
  48 /** Process id of current pre-remove/rm/post-remove process. */
  49 static pid_t remove_pid;
  50 /** When the next snapshot is due. */
  51 static int64_t next_snapshot_time;
  52 /** When to try to remove something. */
  53 static struct timeval next_removal_check;
  54 /** Creation time of the snapshot currently being created. */
  55 static int64_t current_snapshot_creation_time;
  56 /** The snapshot currently being removed. */
  57 struct snapshot *snapshot_currently_being_removed;
  58 /** Needed by the post-create hook. */
  59 static char *path_to_last_complete_snapshot;
  60 static char *name_of_reference_snapshot;
  61 /** \sa \ref snap.h for details. */
  62 enum hook_status snapshot_creation_status;
  63 /** \sa \ref snap.h for details. */
  64 enum hook_status snapshot_removal_status;
  65
  66
  67 DEFINE_DSS_ERRLIST;
  68 static const char *hook_status_description[] = {HOOK_STATUS_ARRAY};
  69
  70 /* may be called with ds == NULL. */
  71 static int disk_space_low(struct disk_space *ds)
  72 {
  73         struct disk_space ds_struct;
  74
  75         if (!ds) {
  76                 int ret = get_disk_space(".", &ds_struct);
  77                 if (ret < 0)
  78                         return ret;
  79                 ds = &ds_struct;
  80         }
  81         if (conf.min_free_mb_arg)
  82                 if (ds->free_mb < conf.min_free_mb_arg)
  83                         return 1;
  84         if (conf.min_free_percent_arg)
  85                 if (ds->percent_free < conf.min_free_percent_arg)
  86                         return 1;
  87         if (conf.min_free_percent_inodes_arg)
  88                 if (ds->percent_free_inodes < conf.min_free_percent_inodes_arg)
  89                         return 1;
  90         return 0;
  91 }
  92
  93 static void dump_dss_config(const char *msg)
  94 {
  95         const char dash[] = "-----------------------------";
  96         int ret;
  97         FILE *log = logfile? logfile : stderr;
  98         struct disk_space ds;
  99         int64_t now = get_current_time();
 100
 101         if (conf.loglevel_arg > INFO)
 102                 return;
 103
 104         fprintf(log, "%s <%s config> %s\n", dash, msg, dash);
 105         fprintf(log, "\n*** disk space ***\n\n");
 106         ret = get_disk_space(".", &ds);
 107         if (ret >= 0) {
 108                 DSS_INFO_LOG(("disk space low: %s\n", disk_space_low(&ds)?
 109                         "yes" : "no"));
 110                 log_disk_space(&ds);
 111         } else
 112                 DSS_ERROR_LOG(("can not get free disk space: %s\n",
 113                         dss_strerror(-ret)));
 114
 115         /* we continue on errors from get_disk_space */
 116
 117         fprintf(log, "\n*** command line and config file options ***\n\n");
 118         cmdline_parser_dump(log, &conf);
 119         fprintf(log, "\n*** internal state ***\n\n");
 120         fprintf(log,
 121                 "pid: %d\n"
 122                 "logile: %s\n"
 123                 "snapshot_currently_being_removed: %s\n"
 124                 "path_to_last_complete_snapshot: %s\n"
 125                 "reference_snapshot: %s\n"
 126                 "snapshot_creation_status: %s\n"
 127                 "snapshot_removal_status: %s\n"
 128                 ,
 129                 (int) getpid(),
 130                 logfile? conf.logfile_arg : "stderr",
 131                 snapshot_currently_being_removed?
 132                         snapshot_currently_being_removed->name : "(none)",
 133                 path_to_last_complete_snapshot?
 134                         path_to_last_complete_snapshot : "(none)",
 135                 name_of_reference_snapshot?
 136                         name_of_reference_snapshot : "(none)",
 137                 hook_status_description[snapshot_creation_status],
 138                 hook_status_description[snapshot_removal_status]
 139         );
 140         if (create_pid != 0)
 141                 fprintf(log,
 142                         "create_pid: %" PRId32 "\n"
 143                         "create process is %sstopped\n"
 144                         ,
 145                         create_pid,
 146                         create_process_stopped? "" : "not "
 147                 );
 148         if (remove_pid != 0)
 149                 fprintf(log, "remove_pid: %" PRId32 "\n", remove_pid);
 150         if (next_snapshot_time != 0)
 151                 fprintf(log, "next snapshot due in %" PRId64 " seconds\n",
 152                         next_snapshot_time - now);
 153         if (current_snapshot_creation_time != 0)
 154                 fprintf(log, "current_snapshot_creation_time: %"
 155                         PRId64 " (%" PRId64 " seconds ago)\n",
 156                         current_snapshot_creation_time,
 157                         now - current_snapshot_creation_time
 158                 );
 159         if (next_removal_check.tv_sec != 0) {
 160                 fprintf(log, "next removal check: %llu (%llu seconds ago)\n",
 161                         (long long unsigned)next_removal_check.tv_sec,
 162                         now - (long long unsigned)next_removal_check.tv_sec
 163                 );
 164
 165         }
 166         fprintf(log, "%s </%s config> %s\n", dash, msg, dash);
 167 }
 168
 169 /* a litte cpp magic helps to DRY */
 170 #define COMMANDS \
 171         COMMAND(ls) \
 172         COMMAND(create) \
 173         COMMAND(prune) \
 174         COMMAND(run) \
 175         COMMAND(kill) \
 176         COMMAND(reload) \
 177
 178 #define COMMAND(x) static int com_ ##x(void);
 179 COMMANDS
 180 #undef COMMAND
 181 #define COMMAND(x) if (conf.x ##_given) return com_ ##x();
 182 static int call_command_handler(void)
 183 {
 184         COMMANDS
 185         DSS_EMERG_LOG(("BUG: did not find command handler\n"));
 186         return -E_BUG;
 187 }
 188 #undef COMMAND
 189 #undef COMMANDS
 190
 191 static int loglevel = -1;
 192 static const char *location_file = NULL;
 193 static int         location_line = -1;
 194 static const char *location_func = NULL;
 195
 196 void dss_log_set_params(int ll, const char *file, int line, const char *func)
 197 {
 198         loglevel = ll;
 199         location_file = file;
 200         location_line = line;
 201         location_func = func;
 202 }
 203
 204 /**
 205  * The log function of dss.
 206  *
 207  * \param ll Loglevel.
 208  * \param fml Usual format string.
 209  *
 210  * All DSS_XXX_LOG() macros use this function.
 211  */
 212 __printf_1_2 void dss_log(const char* fmt,...)
 213 {
 214         va_list argp;
 215         FILE *outfd;
 216         struct tm *tm;
 217         time_t t1;
 218         char str[255] = "";
 219
 220         if (loglevel < conf.loglevel_arg)
 221                 return;
 222         outfd = logfile? logfile : stderr;
 223         time(&t1);
 224         tm = localtime(&t1);
 225         strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
 226         fprintf(outfd, "%s ", str);
 227         if (conf.loglevel_arg <= INFO)
 228                 fprintf(outfd, "%i: ", loglevel);
 229 #ifdef DSS_NO_FUNC_NAMES
 230         fprintf(outfd, "%s:%d: ", location_file, location_line);
 231 #else
 232         fprintf(outfd, "%s: ", location_func);
 233 #endif
 234         va_start(argp, fmt);
 235         vfprintf(outfd, fmt, argp);
 236         va_end(argp);
 237 }
 238
 239 /**
 240  * Print a message either to stdout or to the log file.
 241  */
 242 static __printf_1_2 void dss_msg(const char* fmt,...)
 243 {
 244         FILE *outfd = conf.daemon_given? logfile : stdout;
 245         va_list argp;
 246         va_start(argp, fmt);
 247         vfprintf(outfd, fmt, argp);
 248         va_end(argp);
 249 }
 250
 251 static char *get_config_file_name(void)
 252 {
 253         char *home, *config_file;
 254
 255         if (conf.config_file_given)
 256                 return dss_strdup(conf.config_file_arg);
 257         home = get_homedir();
 258         config_file = make_message("%s/.dssrc", home);
 259         free(home);
 260         return config_file;
 261 }
 262
 263 static int send_signal(int sig)
 264 {
 265         pid_t pid;
 266         char *config_file = get_config_file_name();
 267         int ret = get_dss_pid(config_file, &pid);
 268
 269         free(config_file);
 270         if (ret < 0)
 271                 return ret;
 272         if (conf.dry_run_given) {
 273                 dss_msg("%d\n", (int)pid);
 274                 return 0;
 275         }
 276         ret = kill(pid, sig);
 277         if (ret < 0)
 278                 return -ERRNO_TO_DSS_ERROR(errno);
 279         return 1;
 280 }
 281
 282 static int com_kill(void)
 283 {
 284         return send_signal(SIGTERM);
 285 }
 286
 287 static int com_reload(void)
 288 {
 289         return send_signal(SIGHUP);
 290 }
 291
 292 static void dss_get_snapshot_list(struct snapshot_list *sl)
 293 {
 294         get_snapshot_list(sl, conf.unit_interval_arg, conf.num_intervals_arg);
 295 }
 296
 297 static int64_t compute_next_snapshot_time(void)
 298 {
 299         int64_t x = 0, now = get_current_time(), unit_interval
 300                 = 24 * 3600 * conf.unit_interval_arg, ret;
 301         unsigned wanted = desired_number_of_snapshots(0, conf.num_intervals_arg),
 302                 num_complete_snapshots = 0;
 303         int i;
 304         struct snapshot *s = NULL;
 305         struct snapshot_list sl;
 306
 307         dss_get_snapshot_list(&sl);
 308         FOR_EACH_SNAPSHOT(s, i, &sl) {
 309                 if (!(s->flags & SS_COMPLETE))
 310                         continue;
 311                 num_complete_snapshots++;
 312                 x += s->completion_time - s->creation_time;
 313         }
 314         assert(x >= 0);
 315
 316         ret = now;
 317         if (num_complete_snapshots == 0)
 318                 goto out;
 319         x /= num_complete_snapshots; /* avg time to create one snapshot */
 320         if (unit_interval < x * wanted) /* oops, no sleep at all */
 321                 goto out;
 322         ret = s->completion_time + unit_interval / wanted - x;
 323 out:
 324         free_snapshot_list(&sl);
 325         return ret;
 326 }
 327
 328 static inline void invalidate_next_snapshot_time(void)
 329 {
 330         next_snapshot_time = 0;
 331 }
 332
 333 static inline int next_snapshot_time_is_valid(void)
 334 {
 335         return next_snapshot_time != 0;
 336 }
 337
 338 static int next_snapshot_is_due(void)
 339 {
 340         int64_t now = get_current_time();
 341
 342         if (!next_snapshot_time_is_valid())
 343                 next_snapshot_time = compute_next_snapshot_time();
 344         if (next_snapshot_time <= now) {
 345                 DSS_DEBUG_LOG(("next snapshot: now\n"));
 346                 return 1;
 347         }
 348         DSS_DEBUG_LOG(("next snapshot due in %" PRId64 " seconds\n",
 349                 next_snapshot_time - now));
 350         return 0;
 351 }
 352
 353 static void pre_create_hook(void)
 354 {
 355         assert(snapshot_creation_status == HS_READY);
 356         /* make sure that the next snapshot time will be recomputed */
 357         invalidate_next_snapshot_time();
 358         DSS_DEBUG_LOG(("executing %s\n", conf.pre_create_hook_arg));
 359         dss_exec_cmdline_pid(&create_pid, conf.pre_create_hook_arg);
 360         snapshot_creation_status = HS_PRE_RUNNING;
 361 }
 362
 363 static void pre_remove_hook(struct snapshot *s, const char *why)
 364 {
 365         char *cmd;
 366
 367         if (!s)
 368                 return;
 369         DSS_DEBUG_LOG(("%s snapshot %s\n", why, s->name));
 370         assert(snapshot_removal_status == HS_READY);
 371         assert(remove_pid == 0);
 372         assert(!snapshot_currently_being_removed);
 373
 374         snapshot_currently_being_removed = dss_malloc(sizeof(struct snapshot));
 375         *snapshot_currently_being_removed = *s;
 376         snapshot_currently_being_removed->name = dss_strdup(s->name);
 377
 378         cmd = make_message("%s %s/%s", conf.pre_remove_hook_arg,
 379                 conf.dest_dir_arg, s->name);
 380         DSS_DEBUG_LOG(("executing %s\n", cmd));
 381         dss_exec_cmdline_pid(&remove_pid, cmd);
 382         free(cmd);
 383         snapshot_removal_status = HS_PRE_RUNNING;
 384 }
 385
 386 static int exec_rm(void)
 387 {
 388         struct snapshot *s = snapshot_currently_being_removed;
 389         char *new_name = being_deleted_name(s);
 390         char *argv[4];
 391         int ret;
 392
 393         argv[0] = "rm";
 394         argv[1] = "-rf";
 395         argv[2] = new_name;
 396         argv[3] = NULL;
 397
 398         assert(snapshot_removal_status == HS_PRE_SUCCESS);
 399         assert(remove_pid == 0);
 400
 401         DSS_NOTICE_LOG(("removing %s (interval = %i)\n", s->name, s->interval));
 402         ret = dss_rename(s->name, new_name);
 403         if (ret < 0)
 404                 goto out;
 405         dss_exec(&remove_pid, argv[0], argv);
 406         snapshot_removal_status = HS_RUNNING;
 407 out:
 408         free(new_name);
 409         return ret;
 410 }
 411
 412 static int snapshot_is_being_created(struct snapshot *s)
 413 {
 414         return s->creation_time == current_snapshot_creation_time;
 415 }
 416
 417 static struct snapshot *find_orphaned_snapshot(struct snapshot_list *sl)
 418 {
 419         struct snapshot *s;
 420         int i;
 421
 422         DSS_DEBUG_LOG(("looking for orphaned snapshots\n"));
 423         FOR_EACH_SNAPSHOT(s, i, sl) {
 424                 if (snapshot_is_being_created(s))
 425                         continue;
 426                 /*
 427                  * We know that no rm is currently running, so if s is marked
 428                  * as being deleted, a previously started rm must have failed.
 429                  */
 430                 if (s->flags & SS_BEING_DELETED)
 431                         return s;
 432
 433                 if (s->flags & SS_COMPLETE) /* good snapshot */
 434                         continue;
 435                 /*
 436                  * This snapshot is incomplete and it is not the snapshot
 437                  * currently being created. However, we must not remove it if
 438                  * rsync is about to be restarted. As only the newest snapshot
 439                  * can be restarted, this snapshot is orphaned if it is not the
 440                  * newest snapshot or if we are not about to restart rsync.
 441                  */
 442                 if (get_newest_snapshot(sl) != s)
 443                         return s;
 444                 if (snapshot_creation_status != HS_NEEDS_RESTART)
 445                         return s;
 446         }
 447         /* no orphaned snapshots */
 448         return NULL;
 449 }
 450
 451 static int is_reference_snapshot(struct snapshot *s)
 452 {
 453         if (!name_of_reference_snapshot)
 454                 return 0;
 455         return strcmp(s->name, name_of_reference_snapshot)? 0 : 1;
 456 }
 457
 458 /*
 459  * return: 0: no redundant snapshots, 1: rm process started, negative: error
 460  */
 461 static struct snapshot *find_redundant_snapshot(struct snapshot_list *sl)
 462 {
 463         int i, interval;
 464         struct snapshot *s;
 465         unsigned missing = 0;
 466
 467         DSS_DEBUG_LOG(("looking for intervals containing too many snapshots\n"));
 468         for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
 469                 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
 470                 unsigned num = sl->interval_count[interval];
 471                 struct snapshot *victim = NULL, *prev = NULL;
 472                 int64_t score = LONG_MAX;
 473
 474                 if (keep >= num)
 475                         missing += keep - num;
 476                 if (keep + missing >= num)
 477                         continue;
 478                 /* redundant snapshot in this interval, pick snapshot with lowest score */
 479                 FOR_EACH_SNAPSHOT(s, i, sl) {
 480                         int64_t this_score;
 481
 482                         if (snapshot_is_being_created(s))
 483                                 continue;
 484                         if (is_reference_snapshot(s))
 485                                 continue;
 486                         if (s->interval > interval) {
 487                                 prev = s;
 488                                 continue;
 489                         }
 490                         if (s->interval < interval)
 491                                 break;
 492                         if (!victim) {
 493                                 victim = s;
 494                                 prev = s;
 495                                 continue;
 496                         }
 497                         assert(prev);
 498                         /* check if s is a better victim */
 499                         this_score = s->creation_time - prev->creation_time;
 500                         assert(this_score >= 0);
 501                         if (this_score < score) {
 502                                 score = this_score;
 503                                 victim = s;
 504                         }
 505                         prev = s;
 506                 }
 507                 assert(victim);
 508                 return victim;
 509         }
 510         return NULL;
 511 }
 512
 513 static struct snapshot *find_outdated_snapshot(struct snapshot_list *sl)
 514 {
 515         int i;
 516         struct snapshot *s;
 517
 518         DSS_DEBUG_LOG(("looking for snapshots belonging to intervals >= %d\n",
 519                 conf.num_intervals_arg));
 520         FOR_EACH_SNAPSHOT(s, i, sl) {
 521                 if (snapshot_is_being_created(s))
 522                         continue;
 523                 if (is_reference_snapshot(s))
 524                         continue;
 525                 if (s->interval < conf.num_intervals_arg)
 526                         continue;
 527                 return s;
 528         }
 529         return NULL;
 530 }
 531
 532 static struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
 533 {
 534         int i, num_complete;
 535         struct snapshot *s, *ref = NULL;
 536
 537         num_complete = num_complete_snapshots(sl);
 538         if (num_complete <= conf.min_complete_arg)
 539                 return NULL;
 540         FOR_EACH_SNAPSHOT(s, i, sl) {
 541                 if (snapshot_is_being_created(s))
 542                         continue;
 543                 if (is_reference_snapshot(s)) { /* avoid this one */
 544                         ref = s;
 545                         continue;
 546                 }
 547                 DSS_INFO_LOG(("oldest removable snapshot: %s\n", s->name));
 548                 return s;
 549         }
 550         assert(ref);
 551         DSS_WARNING_LOG(("removing reference snapshot %s\n", ref->name));
 552         return ref;
 553 }
 554
 555 static int rename_incomplete_snapshot(int64_t start)
 556 {
 557         char *old_name;
 558         int ret;
 559         int64_t now;
 560
 561         /*
 562          * We don't want the dss_rename() below to fail with EEXIST because the
 563          * last complete snapshot was created (and completed) in the same
 564          * second as this one.
 565          */
 566         while ((now = get_current_time()) == start)
 567                 sleep(1);
 568         free(path_to_last_complete_snapshot);
 569         ret = complete_name(start, now, &path_to_last_complete_snapshot);
 570         if (ret < 0)
 571                 return ret;
 572         old_name = incomplete_name(start);
 573         ret = dss_rename(old_name, path_to_last_complete_snapshot);
 574         if (ret >= 0)
 575                 DSS_NOTICE_LOG(("%s -> %s\n", old_name,
 576                         path_to_last_complete_snapshot));
 577         free(old_name);
 578         return ret;
 579 }
 580
 581 static int try_to_free_disk_space(void)
 582 {
 583         int ret;
 584         struct snapshot_list sl;
 585         struct snapshot *victim;
 586         struct timeval now;
 587         const char *why;
 588         int low_disk_space;
 589
 590         ret = disk_space_low(NULL);
 591         if (ret < 0)
 592                 return ret;
 593         low_disk_space = ret;
 594         gettimeofday(&now, NULL);
 595         if (tv_diff(&next_removal_check, &now, NULL) > 0)
 596                 return 0;
 597         if (!low_disk_space) {
 598                 if (conf.keep_redundant_given)
 599                         return 0;
 600                 if (snapshot_creation_status != HS_READY)
 601                         return 0;
 602                 if (next_snapshot_is_due())
 603                         return 0;
 604         }
 605         dss_get_snapshot_list(&sl);
 606         ret = 0;
 607         if (!low_disk_space && sl.num_snapshots <= 1)
 608                 goto out;
 609         why = "outdated";
 610         victim = find_outdated_snapshot(&sl);
 611         if (victim)
 612                 goto remove;
 613         why = "redundant";
 614         victim = find_redundant_snapshot(&sl);
 615         if (victim)
 616                 goto remove;
 617         /* try harder only if disk space is low */
 618         if (!low_disk_space)
 619                 goto out;
 620         why = "orphaned";
 621         victim = find_orphaned_snapshot(&sl);
 622         if (victim)
 623                 goto remove;
 624         DSS_WARNING_LOG(("disk space low and nothing obvious to remove\n"));
 625         victim = find_oldest_removable_snapshot(&sl);
 626         if (victim)
 627                 goto remove;
 628         DSS_CRIT_LOG(("uhuhu: disk space low and nothing to remove\n"));
 629         ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
 630         goto out;
 631 remove:
 632         pre_remove_hook(victim, why);
 633 out:
 634         free_snapshot_list(&sl);
 635         return ret;
 636 }
 637
 638 static void post_create_hook(void)
 639 {
 640         char *cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
 641                 conf.dest_dir_arg, path_to_last_complete_snapshot);
 642         DSS_NOTICE_LOG(("executing %s\n", cmd));
 643         dss_exec_cmdline_pid(&create_pid, cmd);
 644         free(cmd);
 645         snapshot_creation_status = HS_POST_RUNNING;
 646 }
 647
 648 static void post_remove_hook(void)
 649 {
 650         char *cmd;
 651         struct snapshot *s = snapshot_currently_being_removed;
 652
 653         assert(s);
 654
 655         cmd = make_message("%s %s/%s", conf.post_remove_hook_arg,
 656                 conf.dest_dir_arg, s->name);
 657         DSS_NOTICE_LOG(("executing %s\n", cmd));
 658         dss_exec_cmdline_pid(&remove_pid, cmd);
 659         free(cmd);
 660         snapshot_removal_status = HS_POST_RUNNING;
 661 }
 662
 663 static void dss_kill(pid_t pid, int sig, const char *msg)
 664 {
 665         const char *signame, *process_name;
 666
 667         if (pid == 0)
 668                 return;
 669         switch (sig) {
 670         case SIGTERM: signame = "TERM"; break;
 671         case SIGSTOP: signame = "STOP"; break;
 672         case SIGCONT: signame = "CONT"; break;
 673         default: signame = "????";
 674         }
 675
 676         if (pid == create_pid)
 677                 process_name = "create";
 678         else if (pid == remove_pid)
 679                 process_name = "remove";
 680         else process_name = "??????";
 681
 682         if (msg)
 683                 DSS_INFO_LOG(("%s\n", msg));
 684         DSS_DEBUG_LOG(("sending signal %d (%s) to pid %d (%s process)\n",
 685                 sig, signame, (int)pid, process_name));
 686         if (kill(pid, sig) >= 0)
 687                 return;
 688         DSS_INFO_LOG(("failed to send signal %d (%s) to pid %d (%s process)\n",
 689                 sig, signame, (int)pid, process_name));
 690 }
 691
 692 static void stop_create_process(void)
 693 {
 694         if (create_process_stopped)
 695                 return;
 696         dss_kill(create_pid, SIGSTOP, "suspending create process");
 697         create_process_stopped = 1;
 698 }
 699
 700 static void restart_create_process(void)
 701 {
 702         if (!create_process_stopped)
 703                 return;
 704         dss_kill(create_pid, SIGCONT, "resuming create process");
 705         create_process_stopped = 0;
 706 }
 707
 708 /**
 709  * Print a log message about the exit status of a child.
 710  */
 711 static void log_termination_msg(pid_t pid, int status)
 712 {
 713         if (WIFEXITED(status))
 714                 DSS_INFO_LOG(("child %i exited. Exit status: %i\n", (int)pid,
 715                         WEXITSTATUS(status)));
 716         else if (WIFSIGNALED(status))
 717                 DSS_NOTICE_LOG(("child %i was killed by signal %i\n", (int)pid,
 718                         WTERMSIG(status)));
 719         else
 720                 DSS_WARNING_LOG(("child %i terminated abormally\n", (int)pid));
 721 }
 722
 723 static int wait_for_process(pid_t pid, int *status)
 724 {
 725         int ret;
 726
 727         DSS_DEBUG_LOG(("Waiting for process %d to terminate\n", (int)pid));
 728         for (;;) {
 729                 fd_set rfds;
 730
 731                 FD_ZERO(&rfds);
 732                 FD_SET(signal_pipe, &rfds);
 733                 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
 734                 if (ret < 0)
 735                         break;
 736                 ret = next_signal();
 737                 if (!ret)
 738                         continue;
 739                 if (ret == SIGCHLD) {
 740                         ret = waitpid(pid, status, 0);
 741                         if (ret >= 0)
 742                                 break;
 743                         if (errno != EINTR) { /* error */
 744                                 ret = -ERRNO_TO_DSS_ERROR(errno);
 745                                 break;
 746                         }
 747                 }
 748                 /* SIGINT or SIGTERM */
 749                 dss_kill(pid, SIGTERM, "killing child process");
 750         }
 751         if (ret < 0)
 752                 DSS_ERROR_LOG(("failed to wait for process %d\n", (int)pid));
 753         else
 754                 log_termination_msg(pid, *status);
 755         return ret;
 756 }
 757
 758 static void handle_pre_remove_exit(int status)
 759 {
 760         if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 761                 snapshot_removal_status = HS_READY;
 762                 gettimeofday(&next_removal_check, NULL);
 763                 next_removal_check.tv_sec += 60;
 764                 return;
 765         }
 766         snapshot_removal_status = HS_PRE_SUCCESS;
 767 }
 768
 769 static int handle_rm_exit(int status)
 770 {
 771         if (!WIFEXITED(status)) {
 772                 snapshot_removal_status = HS_READY;
 773                 return -E_INVOLUNTARY_EXIT;
 774         }
 775         if (WEXITSTATUS(status)) {
 776                 snapshot_removal_status = HS_READY;
 777                 return -E_BAD_EXIT_CODE;
 778         }
 779         snapshot_removal_status = HS_SUCCESS;
 780         return 1;
 781 }
 782
 783 static void handle_post_remove_exit(void)
 784 {
 785         snapshot_removal_status = HS_READY;
 786 }
 787
 788 static int handle_remove_exit(int status)
 789 {
 790         int ret;
 791         struct snapshot *s = snapshot_currently_being_removed;
 792
 793         assert(s);
 794         switch (snapshot_removal_status) {
 795         case HS_PRE_RUNNING:
 796                 handle_pre_remove_exit(status);
 797                 ret = 1;
 798                 break;
 799         case HS_RUNNING:
 800                 ret = handle_rm_exit(status);
 801                 break;
 802         case HS_POST_RUNNING:
 803                 handle_post_remove_exit();
 804                 ret = 1;
 805                 break;
 806         default:
 807                 ret = -E_BUG;
 808         }
 809         if (snapshot_removal_status == HS_READY) {
 810                 free(s->name);
 811                 free(s);
 812                 snapshot_currently_being_removed = NULL;
 813         }
 814         remove_pid = 0;
 815         return ret;
 816 }
 817
 818 static int wait_for_remove_process(void)
 819 {
 820         int status, ret;
 821
 822         assert(remove_pid);
 823         assert(
 824                 snapshot_removal_status == HS_PRE_RUNNING ||
 825                 snapshot_removal_status == HS_RUNNING ||
 826                 snapshot_removal_status == HS_POST_RUNNING
 827         );
 828         ret = wait_for_process(remove_pid, &status);
 829         if (ret < 0)
 830                 return ret;
 831         return handle_remove_exit(status);
 832 }
 833
 834 static int handle_rsync_exit(int status)
 835 {
 836         int es, ret;
 837
 838         if (!WIFEXITED(status)) {
 839                 DSS_ERROR_LOG(("rsync process %d died involuntary\n", (int)create_pid));
 840                 ret = -E_INVOLUNTARY_EXIT;
 841                 snapshot_creation_status = HS_READY;
 842                 goto out;
 843         }
 844         es = WEXITSTATUS(status);
 845         /*
 846          * Restart rsync on non-fatal errors:
 847          * 12: Error in rsync protocol data stream
 848          * 13: Errors with program diagnostics
 849          */
 850         if (es == 12 || es == 13) {
 851                 DSS_WARNING_LOG(("rsync process %d returned %d -- restarting\n",
 852                         (int)create_pid, es));
 853                 snapshot_creation_status = HS_NEEDS_RESTART;
 854                 next_snapshot_time = get_current_time() + 60;
 855                 ret = 1;
 856                 goto out;
 857         }
 858         if (es != 0 && es != 23 && es != 24) {
 859                 DSS_ERROR_LOG(("rsync process %d returned %d\n", (int)create_pid, es));
 860                 ret = -E_BAD_EXIT_CODE;
 861                 snapshot_creation_status = HS_READY;
 862                 goto out;
 863         }
 864         ret = rename_incomplete_snapshot(current_snapshot_creation_time);
 865         if (ret < 0)
 866                 goto out;
 867         snapshot_creation_status = HS_SUCCESS;
 868         free(name_of_reference_snapshot);
 869         name_of_reference_snapshot = NULL;
 870 out:
 871         create_process_stopped = 0;
 872         return ret;
 873 }
 874
 875 static int handle_pre_create_hook_exit(int status)
 876 {
 877         int es, ret;
 878         static int warn_count;
 879
 880         if (!WIFEXITED(status)) {
 881                 snapshot_creation_status = HS_READY;
 882                 ret = -E_INVOLUNTARY_EXIT;
 883                 goto out;
 884         }
 885         es = WEXITSTATUS(status);
 886         if (es) {
 887                 if (!warn_count--) {
 888                         DSS_NOTICE_LOG(("pre_create_hook %s returned %d\n",
 889                                 conf.pre_create_hook_arg, es));
 890                         DSS_NOTICE_LOG(("deferring snapshot creation...\n"));
 891                         warn_count = 60; /* warn only once per hour */
 892                 }
 893                 next_snapshot_time = get_current_time() + 60;
 894                 snapshot_creation_status = HS_READY;
 895                 ret = 0;
 896                 goto out;
 897         }
 898         warn_count = 0;
 899         snapshot_creation_status = HS_PRE_SUCCESS;
 900         ret = 1;
 901 out:
 902         return ret;
 903 }
 904
 905 static int handle_sigchld(void)
 906 {
 907         pid_t pid;
 908         int status, ret = reap_child(&pid, &status);
 909
 910         if (ret <= 0)
 911                 return ret;
 912
 913         if (pid == create_pid) {
 914                 switch (snapshot_creation_status) {
 915                 case HS_PRE_RUNNING:
 916                         ret = handle_pre_create_hook_exit(status);
 917                         break;
 918                 case HS_RUNNING:
 919                         ret = handle_rsync_exit(status);
 920                         break;
 921                 case HS_POST_RUNNING:
 922                         snapshot_creation_status = HS_READY;
 923                         ret = 1;
 924                         break;
 925                 default:
 926                         DSS_EMERG_LOG(("BUG: create can't die in status %d\n",
 927                                 snapshot_creation_status));
 928                         return -E_BUG;
 929                 }
 930                 create_pid = 0;
 931                 return ret;
 932         }
 933         if (pid == remove_pid) {
 934                 ret = handle_remove_exit(status);
 935                 if (ret < 0)
 936                         return ret;
 937                 return ret;
 938         }
 939         DSS_EMERG_LOG(("BUG: unknown process %d died\n", (int)pid));
 940         return -E_BUG;
 941 }
 942
 943 static int check_config(void)
 944 {
 945         if (conf.unit_interval_arg <= 0) {
 946                 DSS_ERROR_LOG(("bad unit interval: %i\n", conf.unit_interval_arg));
 947                 return -E_INVALID_NUMBER;
 948         }
 949         DSS_DEBUG_LOG(("unit interval: %i day(s)\n", conf.unit_interval_arg));
 950         if (conf.num_intervals_arg <= 0 || conf.num_intervals_arg > 30) {
 951                 DSS_ERROR_LOG(("bad number of intervals: %i\n",
 952                         conf.num_intervals_arg));
 953                 return -E_INVALID_NUMBER;
 954         }
 955         DSS_DEBUG_LOG(("number of intervals: %i\n", conf.num_intervals_arg));
 956         return 1;
 957 }
 958
 959 /*
 960  * Returns < 0 on errors, 0 if no config file is given and > 0 if the config
 961  * file was read successfully.
 962  */
 963 static int parse_config_file(int override)
 964 {
 965         int ret, config_file_exists;
 966         char *config_file = get_config_file_name();
 967         struct stat statbuf;
 968         char *old_logfile_arg = NULL;
 969         int old_daemon_given = 0;
 970
 971         if (override) { /* SIGHUP */
 972                 if (conf.logfile_given)
 973                         old_logfile_arg = dss_strdup(conf.logfile_arg);
 974                 old_daemon_given = conf.daemon_given;
 975         }
 976
 977         config_file_exists = !stat(config_file, &statbuf);
 978         if (!config_file_exists && conf.config_file_given) {
 979                 ret = -ERRNO_TO_DSS_ERROR(errno);
 980                 DSS_ERROR_LOG(("failed to stat config file %s\n", config_file));
 981                 goto out;
 982         }
 983         if (config_file_exists) {
 984                 struct cmdline_parser_params params;
 985                 params.override = override;
 986                 params.initialize = 0;
 987                 params.check_required = 1;
 988                 params.check_ambiguity = 0;
 989                 params.print_errors = 1;
 990                 if (override) { /* invalidate all rsync options */
 991                         int i;
 992
 993                         for (i = 0; i < conf.rsync_option_given; i++) {
 994                                 free(conf.rsync_option_arg[i]);
 995                                 conf.rsync_option_arg[i] = NULL;
 996                         }
 997                         conf.rsync_option_given = 0;
 998                 }
 999                 cmdline_parser_config_file(config_file, &conf, &params);
1000         }
1001         ret = check_config();
1002         if (ret < 0)
1003                 goto out;
1004         if (override) {
1005                 /* don't change daemon mode on SIGHUP */
1006                 conf.daemon_given = old_daemon_given;
1007                 close_log(logfile);
1008                 logfile = NULL;
1009                 if (conf.logfile_given)
1010                         free(old_logfile_arg);
1011                 else if (conf.daemon_given) { /* re-use old logfile */
1012                         conf.logfile_arg = old_logfile_arg;
1013                         conf.logfile_given = 1;
1014                 }
1015         }
1016         if (conf.logfile_given && conf.run_given && conf.daemon_given) {
1017                 logfile = open_log(conf.logfile_arg);
1018                 log_welcome(conf.loglevel_arg);
1019         }
1020         DSS_DEBUG_LOG(("loglevel: %d\n", conf.loglevel_arg));
1021         ret = config_file_exists;
1022 out:
1023         free(config_file);
1024         if (ret < 0)
1025                 DSS_EMERG_LOG(("%s\n", dss_strerror(-ret)));
1026         return ret;
1027 }
1028
1029 static int change_to_dest_dir(void)
1030 {
1031         DSS_INFO_LOG(("changing cwd to %s\n", conf.dest_dir_arg));
1032         return dss_chdir(conf.dest_dir_arg);
1033 }
1034
1035 static int handle_sighup(void)
1036 {
1037         int ret;
1038
1039         DSS_NOTICE_LOG(("SIGHUP, re-reading config\n"));
1040         dump_dss_config("old");
1041         ret = parse_config_file(1);
1042         if (ret < 0)
1043                 return ret;
1044         dump_dss_config("reloaded");
1045         invalidate_next_snapshot_time();
1046         return change_to_dest_dir();
1047 }
1048
1049 static void kill_children(void)
1050 {
1051         restart_create_process();
1052         dss_kill(create_pid, SIGTERM, NULL);
1053         dss_kill(remove_pid, SIGTERM, NULL);
1054 }
1055
1056 static int handle_signal(void)
1057 {
1058         int sig, ret = next_signal();
1059
1060         if (ret <= 0)
1061                 goto out;
1062         sig = ret;
1063         switch (sig) {
1064         case SIGINT:
1065         case SIGTERM:
1066                 kill_children();
1067                 ret = -E_SIGNAL;
1068                 break;
1069         case SIGHUP:
1070                 ret = handle_sighup();
1071                 break;
1072         case SIGCHLD:
1073                 ret = handle_sigchld();
1074                 break;
1075         }
1076 out:
1077         if (ret < 0)
1078                 DSS_ERROR_LOG(("%s\n", dss_strerror(-ret)));
1079         return ret;
1080 }
1081
1082 /*
1083  * We can not use rsync locally if the local user is different from the remote
1084  * user or if the src dir is not on the local host (or both).
1085  */
1086 static int use_rsync_locally(char *logname)
1087 {
1088         char *h = conf.remote_host_arg;
1089
1090         if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
1091                 return 0;
1092         if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
1093                 return 0;
1094         return 1;
1095 }
1096
1097 static int rename_resume_snap(int64_t creation_time)
1098 {
1099         struct snapshot_list sl;
1100         struct snapshot *s = NULL;
1101         char *new_name = incomplete_name(creation_time);
1102         int ret;
1103         const char *why;
1104
1105         sl.num_snapshots = 0;
1106
1107         ret = 0;
1108         if (conf.no_resume_given)
1109                 goto out;
1110         dss_get_snapshot_list(&sl);
1111         /*
1112          * Snapshot recycling: We first look at the newest snapshot. If this
1113          * snapshot happens to be incomplete, the last rsync process was
1114          * aborted and we reuse this one. Otherwise we look at snapshots which
1115          * could be removed (outdated and redundant snapshots) as candidates
1116          * for recycling. If no outdated/redundant snapshot exists, we check if
1117          * there is an orphaned snapshot, which likely is useless anyway.
1118          *
1119          * Only if no existing snapshot is suitable for recycling, we bite the
1120          * bullet and create a new one.
1121          */
1122         s = get_newest_snapshot(&sl);
1123         if (!s) /* no snapshots at all */
1124                 goto out;
1125         /* re-use last snapshot if it is incomplete */
1126         why = "aborted";
1127         if ((s->flags & SS_COMPLETE) == 0)
1128                 goto out;
1129         why = "outdated";
1130         s = find_outdated_snapshot(&sl);
1131         if (s)
1132                 goto out;
1133         why = "redundant";
1134         s = find_redundant_snapshot(&sl);
1135         if (s)
1136                 goto out;
1137         why = "orphaned";
1138         s = find_orphaned_snapshot(&sl);
1139 out:
1140         if (s) {
1141                 DSS_INFO_LOG(("reusing %s snapshot %s\n", why, s->name));
1142                 ret = dss_rename(s->name, new_name);
1143         }
1144         if (ret >= 0)
1145                 DSS_NOTICE_LOG(("creating new snapshot %s\n", new_name));
1146         free(new_name);
1147         free_snapshot_list(&sl);
1148         return ret;
1149 }
1150
1151 static void create_rsync_argv(char ***argv, int64_t *num)
1152 {
1153         char *logname;
1154         int i = 0, j;
1155         struct snapshot_list sl;
1156
1157         dss_get_snapshot_list(&sl);
1158         assert(!name_of_reference_snapshot);
1159         name_of_reference_snapshot = name_of_newest_complete_snapshot(&sl);
1160         free_snapshot_list(&sl);
1161
1162         *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
1163         (*argv)[i++] = dss_strdup("rsync");
1164         (*argv)[i++] = dss_strdup("-a");
1165         (*argv)[i++] = dss_strdup("--delete");
1166         for (j = 0; j < conf.rsync_option_given; j++)
1167                 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
1168         if (name_of_reference_snapshot) {
1169                 DSS_INFO_LOG(("using %s as reference\n", name_of_reference_snapshot));
1170                 (*argv)[i++] = make_message("--link-dest=../%s",
1171                         name_of_reference_snapshot);
1172         } else
1173                 DSS_INFO_LOG(("no suitable reference snapshot found\n"));
1174         logname = dss_logname();
1175         if (use_rsync_locally(logname))
1176                 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
1177         else
1178                 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
1179                         conf.remote_user_arg : logname,
1180                         conf.remote_host_arg, conf.source_dir_arg);
1181         free(logname);
1182         *num = get_current_time();
1183         (*argv)[i++] = incomplete_name(*num);
1184         (*argv)[i++] = NULL;
1185         for (j = 0; j < i; j++)
1186                 DSS_DEBUG_LOG(("argv[%d] = %s\n", j, (*argv)[j]));
1187 }
1188
1189 static void free_rsync_argv(char **argv)
1190 {
1191         int i;
1192
1193         if (!argv)
1194                 return;
1195         for (i = 0; argv[i]; i++)
1196                 free(argv[i]);
1197         free(argv);
1198 }
1199
1200 static int create_snapshot(char **argv)
1201 {
1202         int ret;
1203
1204         ret = rename_resume_snap(current_snapshot_creation_time);
1205         if (ret < 0)
1206                 return ret;
1207         dss_exec(&create_pid, argv[0], argv);
1208         snapshot_creation_status = HS_RUNNING;
1209         return ret;
1210 }
1211
1212 static int select_loop(void)
1213 {
1214         int ret;
1215         /* check every 60 seconds for free disk space */
1216         struct timeval tv;
1217         char **rsync_argv = NULL;
1218
1219         for (;;) {
1220                 fd_set rfds;
1221                 struct timeval *tvp;
1222
1223                 if (remove_pid)
1224                         tvp = NULL; /* sleep until rm hook/process dies */
1225                 else { /* sleep one minute */
1226                         tv.tv_sec = 60;
1227                         tv.tv_usec = 0;
1228                         tvp = &tv;
1229                 }
1230                 FD_ZERO(&rfds);
1231                 FD_SET(signal_pipe, &rfds);
1232                 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
1233                 if (ret < 0)
1234                         goto out;
1235                 if (FD_ISSET(signal_pipe, &rfds)) {
1236                         ret = handle_signal();
1237                         if (ret < 0)
1238                                 goto out;
1239                 }
1240                 if (remove_pid)
1241                         continue;
1242                 if (snapshot_removal_status == HS_PRE_SUCCESS) {
1243                         ret = exec_rm();
1244                         if (ret < 0)
1245                                 goto out;
1246                         continue;
1247                 }
1248                 if (snapshot_removal_status == HS_SUCCESS) {
1249                         post_remove_hook();
1250                         continue;
1251                 }
1252                 ret = try_to_free_disk_space();
1253                 if (ret < 0)
1254                         goto out;
1255                 if (snapshot_removal_status != HS_READY) {
1256                         stop_create_process();
1257                         continue;
1258                 }
1259                 restart_create_process();
1260                 switch (snapshot_creation_status) {
1261                 case HS_READY:
1262                         if (!next_snapshot_is_due())
1263                                 continue;
1264                         pre_create_hook();
1265                         continue;
1266                 case HS_PRE_RUNNING:
1267                 case HS_RUNNING:
1268                 case HS_POST_RUNNING:
1269                         continue;
1270                 case HS_PRE_SUCCESS:
1271                         if (!name_of_reference_snapshot) {
1272                                 free_rsync_argv(rsync_argv);
1273                                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1274                         }
1275                         ret = create_snapshot(rsync_argv);
1276                         if (ret < 0)
1277                                 goto out;
1278                         continue;
1279                 case HS_NEEDS_RESTART:
1280                         if (!next_snapshot_is_due())
1281                                 continue;
1282                         ret = create_snapshot(rsync_argv);
1283                         if (ret < 0)
1284                                 goto out;
1285                         continue;
1286                 case HS_SUCCESS:
1287                         post_create_hook();
1288                         continue;
1289                 }
1290         }
1291 out:
1292         return ret;
1293 }
1294
1295 static void exit_hook(int exit_code)
1296 {
1297         char *argv[3];
1298         pid_t pid;
1299
1300         argv[0] = conf.exit_hook_arg;
1301         argv[1] = dss_strerror(-exit_code);
1302         argv[2] = NULL;
1303
1304         DSS_NOTICE_LOG(("executing %s %s\n", argv[0], argv[1]));
1305         dss_exec(&pid, conf.exit_hook_arg, argv);
1306 }
1307
1308 static void lock_dss_or_die(void)
1309 {
1310         char *config_file = get_config_file_name();
1311         int ret = lock_dss(config_file);
1312
1313         free(config_file);
1314         if (ret < 0) {
1315                 DSS_EMERG_LOG(("failed to lock: %s\n", dss_strerror(-ret)));
1316                 exit(EXIT_FAILURE);
1317         }
1318 }
1319
1320 static int com_run(void)
1321 {
1322         int ret;
1323
1324         lock_dss_or_die();
1325         if (conf.dry_run_given) {
1326                 DSS_ERROR_LOG(("dry_run not supported by this command\n"));
1327                 return -E_SYNTAX;
1328         }
1329         ret = install_sighandler(SIGHUP);
1330         if (ret < 0)
1331                 return ret;
1332         ret = select_loop();
1333         if (ret >= 0) /* impossible */
1334                 ret = -E_BUG;
1335         kill_children();
1336         exit_hook(ret);
1337         return ret;
1338 }
1339
1340 static int com_prune(void)
1341 {
1342         int ret;
1343         struct snapshot_list sl;
1344         struct snapshot *victim;
1345         struct disk_space ds;
1346         const char *why;
1347
1348         lock_dss_or_die();
1349         ret = get_disk_space(".", &ds);
1350         if (ret < 0)
1351                 return ret;
1352         log_disk_space(&ds);
1353         dss_get_snapshot_list(&sl);
1354         why = "outdated";
1355         victim = find_outdated_snapshot(&sl);
1356         if (victim)
1357                 goto rm;
1358         why = "redundant";
1359         victim = find_redundant_snapshot(&sl);
1360         if (victim)
1361                 goto rm;
1362         ret = 0;
1363         goto out;
1364 rm:
1365         if (conf.dry_run_given) {
1366                 dss_msg("%s snapshot %s (interval = %i)\n",
1367                         why, victim->name, victim->interval);
1368                 ret = 0;
1369                 goto out;
1370         }
1371         pre_remove_hook(victim, why);
1372         if (snapshot_removal_status == HS_PRE_RUNNING) {
1373                 ret = wait_for_remove_process();
1374                 if (ret < 0)
1375                         goto out;
1376                 if (snapshot_removal_status != HS_PRE_SUCCESS)
1377                         goto out;
1378         }
1379         ret = exec_rm();
1380         if (ret < 0)
1381                 goto out;
1382         ret = wait_for_remove_process();
1383         if (ret < 0)
1384                 goto out;
1385         if (snapshot_removal_status != HS_SUCCESS)
1386                 goto out;
1387         post_remove_hook();
1388         if (snapshot_removal_status != HS_POST_RUNNING)
1389                 goto out;
1390         ret = wait_for_remove_process();
1391         if (ret < 0)
1392                 goto out;
1393         ret = 1;
1394 out:
1395         free_snapshot_list(&sl);
1396         return ret;
1397 }
1398
1399 static int com_create(void)
1400 {
1401         int ret, status;
1402         char **rsync_argv;
1403
1404         lock_dss_or_die();
1405         if (conf.dry_run_given) {
1406                 int i;
1407                 char *msg = NULL;
1408                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1409                 for (i = 0; rsync_argv[i]; i++) {
1410                         char *tmp = msg;
1411                         msg = make_message("%s%s%s", tmp? tmp : "",
1412                                 tmp? " " : "", rsync_argv[i]);
1413                         free(tmp);
1414                 }
1415                 free_rsync_argv(rsync_argv);
1416                 dss_msg("%s\n", msg);
1417                 free(msg);
1418                 return 1;
1419         }
1420         pre_create_hook();
1421         if (create_pid) {
1422                 ret = wait_for_process(create_pid, &status);
1423                 if (ret < 0)
1424                         return ret;
1425                 ret = handle_pre_create_hook_exit(status);
1426                 if (ret <= 0) /* error, or pre-create failed */
1427                         return ret;
1428         }
1429         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1430         ret = create_snapshot(rsync_argv);
1431         if (ret < 0)
1432                 goto out;
1433         ret = wait_for_process(create_pid, &status);
1434         if (ret < 0)
1435                 goto out;
1436         ret = handle_rsync_exit(status);
1437         if (ret < 0)
1438                 goto out;
1439         post_create_hook();
1440         if (create_pid)
1441                 ret = wait_for_process(create_pid, &status);
1442 out:
1443         free_rsync_argv(rsync_argv);
1444         return ret;
1445 }
1446
1447 static int com_ls(void)
1448 {
1449         int i;
1450         struct snapshot_list sl;
1451         struct snapshot *s;
1452
1453         dss_get_snapshot_list(&sl);
1454         FOR_EACH_SNAPSHOT(s, i, &sl) {
1455                 int64_t d = 0;
1456                 if (s->flags & SS_COMPLETE)
1457                         d = (s->completion_time - s->creation_time) / 60;
1458                 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1459         }
1460         free_snapshot_list(&sl);
1461         return 1;
1462 }
1463
1464 static int setup_signal_handling(void)
1465 {
1466         int ret;
1467
1468         DSS_INFO_LOG(("setting up signal handlers\n"));
1469         signal_pipe = signal_init(); /* always successful */
1470         ret = install_sighandler(SIGINT);
1471         if (ret < 0)
1472                 return ret;
1473         ret = install_sighandler(SIGTERM);
1474         if (ret < 0)
1475                 return ret;
1476         return install_sighandler(SIGCHLD);
1477 }
1478
1479 /**
1480  * The main function of dss.
1481  *
1482  * \param argc Usual argument count.
1483  * \param argv Usual argument vector.
1484  */
1485 int main(int argc, char **argv)
1486 {
1487         int ret;
1488         struct cmdline_parser_params params;
1489
1490         params.override = 0;
1491         params.initialize = 1;
1492         params.check_required = 0;
1493         params.check_ambiguity = 0;
1494         params.print_errors = 1;
1495
1496         cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1497         ret = parse_config_file(0);
1498         if (ret < 0)
1499                 goto out;
1500         if (ret == 0) { /* no config file given */
1501                 /*
1502                  * Parse the command line options again, but this time check
1503                  * that all required options are given.
1504                  */
1505                 struct cmdline_parser_params params;
1506                 params.override = 1;
1507                 params.initialize = 1;
1508                 params.check_required = 1;
1509                 params.check_ambiguity = 1;
1510                 params.print_errors = 1;
1511                 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1512         }
1513         if (conf.daemon_given)
1514                 daemon_init();
1515         ret = change_to_dest_dir();
1516         if (ret < 0)
1517                 goto out;
1518         dump_dss_config("startup");
1519         ret = setup_signal_handling();
1520         if (ret < 0)
1521                 goto out;
1522         ret = call_command_handler();
1523 out:
1524         if (ret < 0)
1525                 DSS_EMERG_LOG(("%s\n", dss_strerror(-ret)));
1526         exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1527 }