dss.c

   1 /*
   2  * Copyright (C) 2008-2010 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 #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 const *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 /**
 192  * The log function of dss.
 193  *
 194  * \param ll Loglevel.
 195  * \param fml Usual format string.
 196  *
 197  * All DSS_XXX_LOG() macros use this function.
 198  */
 199 __printf_2_3 void dss_log(int ll, const char* fmt,...)
 200 {
 201         va_list argp;
 202         FILE *outfd;
 203         struct tm *tm;
 204         time_t t1;
 205         char str[255] = "";
 206
 207         if (ll < conf.loglevel_arg)
 208                 return;
 209         outfd = logfile? logfile : stderr;
 210         time(&t1);
 211         tm = localtime(&t1);
 212         strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
 213         fprintf(outfd, "%s ", str);
 214         if (conf.loglevel_arg <= INFO)
 215                 fprintf(outfd, "%i: ", ll);
 216         va_start(argp, fmt);
 217         vfprintf(outfd, fmt, argp);
 218         va_end(argp);
 219 }
 220
 221 /**
 222  * Print a message either to stdout or to the log file.
 223  */
 224 static __printf_1_2 void dss_msg(const char* fmt,...)
 225 {
 226         FILE *outfd = conf.daemon_given? logfile : stdout;
 227         va_list argp;
 228         va_start(argp, fmt);
 229         vfprintf(outfd, fmt, argp);
 230         va_end(argp);
 231 }
 232
 233 static char *get_config_file_name(void)
 234 {
 235         char *home, *config_file;
 236
 237         if (conf.config_file_given)
 238                 return dss_strdup(conf.config_file_arg);
 239         home = get_homedir();
 240         config_file = make_message("%s/.dssrc", home);
 241         free(home);
 242         return config_file;
 243 }
 244
 245 static int send_signal(int sig)
 246 {
 247         pid_t pid;
 248         char *config_file = get_config_file_name();
 249         int ret = get_dss_pid(config_file, &pid);
 250
 251         free(config_file);
 252         if (ret < 0)
 253                 return ret;
 254         if (conf.dry_run_given) {
 255                 dss_msg("%d\n", (int)pid);
 256                 return 0;
 257         }
 258         ret = kill(pid, sig);
 259         if (ret < 0)
 260                 return -ERRNO_TO_DSS_ERROR(errno);
 261         return 1;
 262 }
 263
 264 static int com_kill(void)
 265 {
 266         return send_signal(SIGTERM);
 267 }
 268
 269 static int com_reload(void)
 270 {
 271         return send_signal(SIGHUP);
 272 }
 273
 274 static void dss_get_snapshot_list(struct snapshot_list *sl)
 275 {
 276         get_snapshot_list(sl, conf.unit_interval_arg, conf.num_intervals_arg);
 277 }
 278
 279 static int64_t compute_next_snapshot_time(void)
 280 {
 281         int64_t x = 0, now = get_current_time(), unit_interval
 282                 = 24 * 3600 * conf.unit_interval_arg, ret;
 283         unsigned wanted = desired_number_of_snapshots(0, conf.num_intervals_arg),
 284                 num_complete_snapshots = 0;
 285         int i;
 286         struct snapshot *s = NULL;
 287         struct snapshot_list sl;
 288
 289         dss_get_snapshot_list(&sl);
 290         FOR_EACH_SNAPSHOT(s, i, &sl) {
 291                 if (!(s->flags & SS_COMPLETE))
 292                         continue;
 293                 num_complete_snapshots++;
 294                 x += s->completion_time - s->creation_time;
 295         }
 296         assert(x >= 0);
 297
 298         ret = now;
 299         if (num_complete_snapshots == 0)
 300                 goto out;
 301         x /= num_complete_snapshots; /* avg time to create one snapshot */
 302         if (unit_interval < x * wanted) /* oops, no sleep at all */
 303                 goto out;
 304         ret = s->completion_time + unit_interval / wanted - x;
 305 out:
 306         free_snapshot_list(&sl);
 307         return ret;
 308 }
 309
 310 static inline void invalidate_next_snapshot_time(void)
 311 {
 312         next_snapshot_time = 0;
 313 }
 314
 315 static inline int next_snapshot_time_is_valid(void)
 316 {
 317         return next_snapshot_time != 0;
 318 }
 319
 320 static int next_snapshot_is_due(void)
 321 {
 322         int64_t now = get_current_time();
 323
 324         if (!next_snapshot_time_is_valid())
 325                 next_snapshot_time = compute_next_snapshot_time();
 326         if (next_snapshot_time <= now) {
 327                 DSS_DEBUG_LOG("next snapshot: now\n");
 328                 return 1;
 329         }
 330         DSS_DEBUG_LOG("next snapshot due in %" PRId64 " seconds\n",
 331                 next_snapshot_time - now);
 332         return 0;
 333 }
 334
 335 static int pre_create_hook(void)
 336 {
 337         int ret, fds[3] = {0, 0, 0};
 338
 339         assert(snapshot_creation_status == HS_READY);
 340         /* make sure that the next snapshot time will be recomputed */
 341         invalidate_next_snapshot_time();
 342         DSS_DEBUG_LOG("executing %s\n", conf.pre_create_hook_arg);
 343         ret = dss_exec_cmdline_pid(&create_pid,
 344                 conf.pre_create_hook_arg, fds);
 345         if (ret < 0)
 346                 return ret;
 347         snapshot_creation_status = HS_PRE_RUNNING;
 348         return ret;
 349 }
 350
 351 static int pre_remove_hook(struct snapshot *s, const char *why)
 352 {
 353         int ret, fds[3] = {0, 0, 0};
 354         char *cmd;
 355
 356         if (!s)
 357                 return 0;
 358         DSS_DEBUG_LOG("%s snapshot %s\n", why, s->name);
 359         assert(snapshot_removal_status == HS_READY);
 360         assert(remove_pid == 0);
 361         assert(!snapshot_currently_being_removed);
 362
 363         snapshot_currently_being_removed = dss_malloc(sizeof(struct snapshot));
 364         *snapshot_currently_being_removed = *s;
 365         snapshot_currently_being_removed->name = dss_strdup(s->name);
 366
 367         cmd = make_message("%s %s/%s", conf.pre_remove_hook_arg,
 368                 conf.dest_dir_arg, s->name);
 369         DSS_DEBUG_LOG("executing %s\n", cmd);
 370         ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
 371         free(cmd);
 372         if (ret < 0)
 373                 return ret;
 374         snapshot_removal_status = HS_PRE_RUNNING;
 375         return ret;
 376 }
 377
 378 static int exec_rm(void)
 379 {
 380         struct snapshot *s = snapshot_currently_being_removed;
 381         int fds[3] = {0, 0, 0};
 382         char *new_name = being_deleted_name(s);
 383         char *argv[] = {"rm", "-rf", new_name, NULL};
 384         int ret;
 385
 386         assert(snapshot_removal_status == HS_PRE_SUCCESS);
 387         assert(remove_pid == 0);
 388
 389         DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
 390         ret = dss_rename(s->name, new_name);
 391         if (ret < 0)
 392                 goto out;
 393         ret = dss_exec(&remove_pid, argv[0], argv, fds);
 394         if (ret < 0)
 395                 goto out;
 396         snapshot_removal_status = HS_RUNNING;
 397 out:
 398         free(new_name);
 399         return ret;
 400 }
 401
 402 static int snapshot_is_being_created(struct snapshot *s)
 403 {
 404         return s->creation_time == current_snapshot_creation_time;
 405 }
 406
 407 static struct snapshot *find_orphaned_snapshot(struct snapshot_list *sl)
 408 {
 409         struct snapshot *s;
 410         int i;
 411
 412         DSS_DEBUG_LOG("looking for orphaned snapshots\n");
 413         FOR_EACH_SNAPSHOT(s, i, sl) {
 414                 if (snapshot_is_being_created(s))
 415                         continue;
 416                 /*
 417                  * We know that no rm is currently running, so if s is marked
 418                  * as being deleted, a previously started rm must have failed.
 419                  */
 420                 if (s->flags & SS_BEING_DELETED)
 421                         return s;
 422
 423                 if (s->flags & SS_COMPLETE) /* good snapshot */
 424                         continue;
 425                 /*
 426                  * This snapshot is incomplete and it is not the snapshot
 427                  * currently being created. However, we must not remove it if
 428                  * rsync is about to be restarted. As only the newest snapshot
 429                  * can be restarted, this snapshot is orphaned if it is not the
 430                  * newest snapshot or if we are not about to restart rsync.
 431                  */
 432                 if (get_newest_snapshot(sl) != s)
 433                         return s;
 434                 if (snapshot_creation_status != HS_NEEDS_RESTART)
 435                         return s;
 436         }
 437         /* no orphaned snapshots */
 438         return NULL;
 439 }
 440
 441 static int is_reference_snapshot(struct snapshot *s)
 442 {
 443         if (!name_of_reference_snapshot)
 444                 return 0;
 445         return strcmp(s->name, name_of_reference_snapshot)? 0 : 1;
 446 }
 447
 448 /*
 449  * return: 0: no redundant snapshots, 1: rm process started, negative: error
 450  */
 451 static struct snapshot *find_redundant_snapshot(struct snapshot_list *sl)
 452 {
 453         int i, interval;
 454         struct snapshot *s;
 455         unsigned missing = 0;
 456
 457         DSS_DEBUG_LOG("looking for intervals containing too many snapshots\n");
 458         for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
 459                 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
 460                 unsigned num = sl->interval_count[interval];
 461                 struct snapshot *victim = NULL, *prev = NULL;
 462                 int64_t score = LONG_MAX;
 463
 464                 if (keep >= num)
 465                         missing += keep - num;
 466 //              DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
 467 //                      interval, keep, num, missing);
 468                 if (keep + missing >= num)
 469                         continue;
 470                 /* redundant snapshot in this interval, pick snapshot with lowest score */
 471                 FOR_EACH_SNAPSHOT(s, i, sl) {
 472                         int64_t this_score;
 473
 474                         if (snapshot_is_being_created(s))
 475                                 continue;
 476                         if (is_reference_snapshot(s))
 477                                 continue;
 478                         //DSS_DEBUG_LOG("checking %s\n", s->name);
 479                         if (s->interval > interval) {
 480                                 prev = s;
 481                                 continue;
 482                         }
 483                         if (s->interval < interval)
 484                                 break;
 485                         if (!victim) {
 486                                 victim = s;
 487                                 prev = s;
 488                                 continue;
 489                         }
 490                         assert(prev);
 491                         /* check if s is a better victim */
 492                         this_score = s->creation_time - prev->creation_time;
 493                         assert(this_score >= 0);
 494                         //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
 495                         if (this_score < score) {
 496                                 score = this_score;
 497                                 victim = s;
 498                         }
 499                         prev = s;
 500                 }
 501                 assert(victim);
 502                 return victim;
 503         }
 504         return NULL;
 505 }
 506
 507 static struct snapshot *find_outdated_snapshot(struct snapshot_list *sl)
 508 {
 509         int i;
 510         struct snapshot *s;
 511
 512         DSS_DEBUG_LOG("looking for snapshots belonging to intervals >= %d\n",
 513                 conf.num_intervals_arg);
 514         FOR_EACH_SNAPSHOT(s, i, sl) {
 515                 if (snapshot_is_being_created(s))
 516                         continue;
 517                 if (is_reference_snapshot(s))
 518                         continue;
 519                 if (s->interval < conf.num_intervals_arg)
 520                         continue;
 521                 return s;
 522         }
 523         return NULL;
 524 }
 525
 526 struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
 527 {
 528         int i;
 529         struct snapshot *s;
 530         FOR_EACH_SNAPSHOT(s, i, sl) {
 531                 if (snapshot_is_being_created(s))
 532                         continue;
 533                 if (is_reference_snapshot(s))
 534                         continue;
 535                 DSS_INFO_LOG("oldest removable snapshot: %s\n", s->name);
 536                 return s;
 537         }
 538         return NULL;
 539 }
 540
 541 static int rename_incomplete_snapshot(int64_t start)
 542 {
 543         char *old_name;
 544         int ret;
 545
 546         free(path_to_last_complete_snapshot);
 547         ret = complete_name(start, get_current_time(),
 548                 &path_to_last_complete_snapshot);
 549         if (ret < 0)
 550                 return ret;
 551         old_name = incomplete_name(start);
 552         ret = dss_rename(old_name, path_to_last_complete_snapshot);
 553         if (ret >= 0)
 554                 DSS_NOTICE_LOG("%s -> %s\n", old_name,
 555                         path_to_last_complete_snapshot);
 556         free(old_name);
 557         return ret;
 558 }
 559
 560 static int try_to_free_disk_space(void)
 561 {
 562         int ret;
 563         struct snapshot_list sl;
 564         struct snapshot *victim;
 565         struct timeval now;
 566         const char *why;
 567         int low_disk_space;
 568
 569         ret = disk_space_low(NULL);
 570         if (ret < 0)
 571                 return ret;
 572         low_disk_space = ret;
 573         gettimeofday(&now, NULL);
 574         if (tv_diff(&next_removal_check, &now, NULL) > 0)
 575                 return 0;
 576         if (!low_disk_space) {
 577                 if (conf.keep_redundant_given)
 578                         return 0;
 579                 if (snapshot_creation_status != HS_READY)
 580                         return 0;
 581                 if (next_snapshot_is_due())
 582                         return 0;
 583         }
 584         dss_get_snapshot_list(&sl);
 585         ret = 0;
 586         if (!low_disk_space && sl.num_snapshots <= 1)
 587                 goto out;
 588         why = "outdated";
 589         victim = find_outdated_snapshot(&sl);
 590         if (victim)
 591                 goto remove;
 592         why = "redundant";
 593         victim = find_redundant_snapshot(&sl);
 594         if (victim)
 595                 goto remove;
 596         /* try harder only if disk space is low */
 597         if (!low_disk_space)
 598                 goto out;
 599         why = "orphaned";
 600         victim = find_orphaned_snapshot(&sl);
 601         if (victim)
 602                 goto remove;
 603         DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
 604         victim = find_oldest_removable_snapshot(&sl);
 605         if (victim)
 606                 goto remove;
 607         DSS_CRIT_LOG("uhuhu: disk space low and nothing to remove\n");
 608         ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
 609         goto out;
 610 remove:
 611         ret = pre_remove_hook(victim, why);
 612 out:
 613         free_snapshot_list(&sl);
 614         return ret;
 615 }
 616
 617 static int post_create_hook(void)
 618 {
 619         int ret, fds[3] = {0, 0, 0};
 620         char *cmd;
 621
 622         cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
 623                 conf.dest_dir_arg, path_to_last_complete_snapshot);
 624         DSS_NOTICE_LOG("executing %s\n", cmd);
 625         ret = dss_exec_cmdline_pid(&create_pid, cmd, fds);
 626         free(cmd);
 627         if (ret < 0)
 628                 return ret;
 629         snapshot_creation_status = HS_POST_RUNNING;
 630         return ret;
 631 }
 632
 633 static int post_remove_hook(void)
 634 {
 635         int ret, fds[3] = {0, 0, 0};
 636         char *cmd;
 637         struct snapshot *s = snapshot_currently_being_removed;
 638
 639         assert(s);
 640
 641         cmd = make_message("%s %s/%s", conf.post_remove_hook_arg,
 642                 conf.dest_dir_arg, s->name);
 643         DSS_NOTICE_LOG("executing %s\n", cmd);
 644         ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
 645         free(cmd);
 646         if (ret < 0)
 647                 return ret;
 648         snapshot_removal_status = HS_POST_RUNNING;
 649         return ret;
 650 }
 651
 652 static void dss_kill(pid_t pid, int sig, const char *msg)
 653 {
 654         const char *signame, *process_name;
 655
 656         if (pid == 0)
 657                 return;
 658         switch (sig) {
 659         case SIGTERM: signame = "TERM"; break;
 660         case SIGSTOP: signame = "STOP"; break;
 661         case SIGCONT: signame = "CONT"; break;
 662         default: signame = "????";
 663         }
 664
 665         if (pid == create_pid)
 666                 process_name = "create";
 667         else if (pid == remove_pid)
 668                 process_name = "remove";
 669         else process_name = "??????";
 670
 671         if (msg)
 672                 DSS_INFO_LOG("%s\n", msg);
 673         DSS_DEBUG_LOG("sending signal %d (%s) to pid %d (%s process)\n",
 674                 sig, signame, (int)pid, process_name);
 675         if (kill(pid, sig) >= 0)
 676                 return;
 677         DSS_INFO_LOG("failed to send signal %d (%s) to pid %d (%s process)\n",
 678                 sig, signame, (int)pid, process_name);
 679 }
 680
 681 static void stop_create_process(void)
 682 {
 683         if (create_process_stopped)
 684                 return;
 685         dss_kill(create_pid, SIGSTOP, "suspending create process");
 686         create_process_stopped = 1;
 687 }
 688
 689 static void restart_create_process(void)
 690 {
 691         if (!create_process_stopped)
 692                 return;
 693         dss_kill(create_pid, SIGCONT, "resuming create process");
 694         create_process_stopped = 0;
 695 }
 696
 697 /**
 698  * Print a log message about the exit status of a child.
 699  */
 700 static void log_termination_msg(pid_t pid, int status)
 701 {
 702         if (WIFEXITED(status))
 703                 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
 704                         WEXITSTATUS(status));
 705         else if (WIFSIGNALED(status))
 706                 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
 707                         WTERMSIG(status));
 708         else
 709                 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
 710 }
 711
 712 static int wait_for_process(pid_t pid, int *status)
 713 {
 714         int ret;
 715
 716         DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
 717         for (;;) {
 718                 fd_set rfds;
 719
 720                 FD_ZERO(&rfds);
 721                 FD_SET(signal_pipe, &rfds);
 722                 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
 723                 if (ret < 0)
 724                         break;
 725                 ret = next_signal();
 726                 if (!ret)
 727                         continue;
 728                 if (ret == SIGCHLD) {
 729                         ret = waitpid(pid, status, 0);
 730                         if (ret >= 0)
 731                                 break;
 732                         if (errno != EINTR) { /* error */
 733                                 ret = -ERRNO_TO_DSS_ERROR(errno);
 734                                 break;
 735                         }
 736                 }
 737                 /* SIGINT or SIGTERM */
 738                 dss_kill(pid, SIGTERM, "killing child process");
 739         }
 740         if (ret < 0)
 741                 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
 742         else
 743                 log_termination_msg(pid, *status);
 744         return ret;
 745 }
 746
 747 static void handle_pre_remove_exit(int status)
 748 {
 749         if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 750                 snapshot_removal_status = HS_READY;
 751                 gettimeofday(&next_removal_check, NULL);
 752                 next_removal_check.tv_sec += 60;
 753                 return;
 754         }
 755         snapshot_removal_status = HS_PRE_SUCCESS;
 756 }
 757
 758 static int handle_rm_exit(int status)
 759 {
 760         if (!WIFEXITED(status)) {
 761                 snapshot_removal_status = HS_READY;
 762                 return -E_INVOLUNTARY_EXIT;
 763         }
 764         if (WEXITSTATUS(status)) {
 765                 snapshot_removal_status = HS_READY;
 766                 return -E_BAD_EXIT_CODE;
 767         }
 768         snapshot_removal_status = HS_SUCCESS;
 769         return 1;
 770 }
 771
 772 static void handle_post_remove_exit(void)
 773 {
 774         snapshot_removal_status = HS_READY;
 775 }
 776
 777 static int handle_remove_exit(int status)
 778 {
 779         int ret;
 780         struct snapshot *s = snapshot_currently_being_removed;
 781
 782         assert(s);
 783         switch (snapshot_removal_status) {
 784         case HS_PRE_RUNNING:
 785                 handle_pre_remove_exit(status);
 786                 ret = 1;
 787                 break;
 788         case HS_RUNNING:
 789                 ret = handle_rm_exit(status);
 790                 break;
 791         case HS_POST_RUNNING:
 792                 handle_post_remove_exit();
 793                 ret = 1;
 794                 break;
 795         default:
 796                 ret = -E_BUG;
 797         }
 798         if (snapshot_removal_status == HS_READY) {
 799                 free(s->name);
 800                 free(s);
 801                 snapshot_currently_being_removed = NULL;
 802         }
 803         remove_pid = 0;
 804         return ret;
 805 }
 806
 807 static int wait_for_remove_process(void)
 808 {
 809         int status, ret;
 810
 811         assert(remove_pid);
 812         assert(
 813                 snapshot_removal_status == HS_PRE_RUNNING ||
 814                 snapshot_removal_status == HS_RUNNING ||
 815                 snapshot_removal_status == HS_POST_RUNNING
 816         );
 817         ret = wait_for_process(remove_pid, &status);
 818         if (ret < 0)
 819                 return ret;
 820         return handle_remove_exit(status);
 821 }
 822
 823 static int handle_rsync_exit(int status)
 824 {
 825         int es, ret;
 826
 827         if (!WIFEXITED(status)) {
 828                 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)create_pid);
 829                 ret = -E_INVOLUNTARY_EXIT;
 830                 snapshot_creation_status = HS_READY;
 831                 goto out;
 832         }
 833         es = WEXITSTATUS(status);
 834         /*
 835          * Restart rsync on non-fatal errors:
 836          * 12: Error in rsync protocol data stream
 837          * 13: Errors with program diagnostics
 838          */
 839         if (es == 12 || es == 13) {
 840                 DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
 841                         (int)create_pid, es);
 842                 snapshot_creation_status = HS_NEEDS_RESTART;
 843                 next_snapshot_time = get_current_time() + 60;
 844                 ret = 1;
 845                 goto out;
 846         }
 847         if (es != 0 && es != 23 && es != 24) {
 848                 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)create_pid, es);
 849                 ret = -E_BAD_EXIT_CODE;
 850                 snapshot_creation_status = HS_READY;
 851                 goto out;
 852         }
 853         ret = rename_incomplete_snapshot(current_snapshot_creation_time);
 854         if (ret < 0)
 855                 goto out;
 856         snapshot_creation_status = HS_SUCCESS;
 857         free(name_of_reference_snapshot);
 858         name_of_reference_snapshot = NULL;
 859 out:
 860         create_process_stopped = 0;
 861         return ret;
 862 }
 863
 864 static int handle_pre_create_hook_exit(int status)
 865 {
 866         int es, ret;
 867         static int warn_count;
 868
 869         if (!WIFEXITED(status)) {
 870                 snapshot_creation_status = HS_READY;
 871                 ret = -E_INVOLUNTARY_EXIT;
 872                 goto out;
 873         }
 874         es = WEXITSTATUS(status);
 875         if (es) {
 876                 if (!warn_count--) {
 877                         DSS_NOTICE_LOG("pre_create_hook %s returned %d\n",
 878                                 conf.pre_create_hook_arg, es);
 879                         DSS_NOTICE_LOG("deferring snapshot creation...\n");
 880                         warn_count = 60; /* warn only once per hour */
 881                 }
 882                 next_snapshot_time = get_current_time() + 60;
 883                 snapshot_creation_status = HS_READY;
 884                 ret = 0;
 885                 goto out;
 886         }
 887         warn_count = 0;
 888         snapshot_creation_status = HS_PRE_SUCCESS;
 889         ret = 1;
 890 out:
 891         return ret;
 892 }
 893
 894 static int handle_sigchld(void)
 895 {
 896         pid_t pid;
 897         int status, ret = reap_child(&pid, &status);
 898
 899         if (ret <= 0)
 900                 return ret;
 901
 902         if (pid == create_pid) {
 903                 switch (snapshot_creation_status) {
 904                 case HS_PRE_RUNNING:
 905                         ret = handle_pre_create_hook_exit(status);
 906                         break;
 907                 case HS_RUNNING:
 908                         ret = handle_rsync_exit(status);
 909                         break;
 910                 case HS_POST_RUNNING:
 911                         snapshot_creation_status = HS_READY;
 912                         ret = 1;
 913                         break;
 914                 default:
 915                         DSS_EMERG_LOG("BUG: create can't die in status %d\n",
 916                                 snapshot_creation_status);
 917                         return -E_BUG;
 918                 }
 919                 create_pid = 0;
 920                 return ret;
 921         }
 922         if (pid == remove_pid) {
 923                 ret = handle_remove_exit(status);
 924                 if (ret < 0)
 925                         return ret;
 926                 return ret;
 927         }
 928         DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
 929         return -E_BUG;
 930 }
 931
 932 static int check_config(void)
 933 {
 934         if (conf.unit_interval_arg <= 0) {
 935                 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
 936                 return -E_INVALID_NUMBER;
 937         }
 938         DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
 939         if (conf.num_intervals_arg <= 0) {
 940                 DSS_ERROR_LOG("bad number of intervals  %i\n", conf.num_intervals_arg);
 941                 return -E_INVALID_NUMBER;
 942         }
 943         DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
 944         return 1;
 945 }
 946
 947 /*
 948  * Returns < 0 on errors, 0 if no config file is given and > 0 if the config
 949  * file was read successfully.
 950  */
 951 static int parse_config_file(int override)
 952 {
 953         int ret, config_file_exists;
 954         char *config_file = get_config_file_name();
 955         struct stat statbuf;
 956         char *old_logfile_arg = NULL;
 957         int old_daemon_given = 0;
 958
 959         if (override) { /* SIGHUP */
 960                 if (conf.logfile_given)
 961                         old_logfile_arg = dss_strdup(conf.logfile_arg);
 962                 old_daemon_given = conf.daemon_given;
 963         }
 964
 965         config_file_exists = !stat(config_file, &statbuf);
 966         if (!config_file_exists && conf.config_file_given) {
 967                 ret = -ERRNO_TO_DSS_ERROR(errno);
 968                 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
 969                 goto out;
 970         }
 971         if (config_file_exists) {
 972                 struct cmdline_parser_params params = {
 973                         .override = override,
 974                         .initialize = 0,
 975                         .check_required = 1,
 976                         .check_ambiguity = 0,
 977                         .print_errors = 1
 978                 };
 979                 if (override) { /* invalidate all rsync options */
 980                         int i;
 981
 982                         for (i = 0; i < conf.rsync_option_given; i++) {
 983                                 free(conf.rsync_option_arg[i]);
 984                                 conf.rsync_option_arg[i] = NULL;
 985                         }
 986                         conf.rsync_option_given = 0;
 987                 }
 988                 cmdline_parser_config_file(config_file, &conf, &params);
 989         }
 990         ret = check_config();
 991         if (ret < 0)
 992                 goto out;
 993         if (override) {
 994                 /* don't change daemon mode on SIGHUP */
 995                 conf.daemon_given = old_daemon_given;
 996                 close_log(logfile);
 997                 logfile = NULL;
 998                 if (conf.logfile_given)
 999                         free(old_logfile_arg);
1000                 else if (conf.daemon_given) { /* re-use old logfile */
1001                         conf.logfile_arg = old_logfile_arg;
1002                         conf.logfile_given = 1;
1003                 }
1004         }
1005         if (conf.logfile_given && conf.run_given && conf.daemon_given) {
1006                 logfile = open_log(conf.logfile_arg);
1007                 log_welcome(conf.loglevel_arg);
1008         }
1009         DSS_DEBUG_LOG("loglevel: %d\n", conf.loglevel_arg);
1010         ret = config_file_exists;
1011 out:
1012         free(config_file);
1013         if (ret < 0)
1014                 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1015         return ret;
1016 }
1017
1018 static int change_to_dest_dir(void)
1019 {
1020         DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
1021         return dss_chdir(conf.dest_dir_arg);
1022 }
1023
1024 static int handle_sighup(void)
1025 {
1026         int ret;
1027
1028         DSS_NOTICE_LOG("SIGHUP, re-reading config\n");
1029         dump_dss_config("old");
1030         ret = parse_config_file(1);
1031         if (ret < 0)
1032                 return ret;
1033         dump_dss_config("reloaded");
1034         invalidate_next_snapshot_time();
1035         return change_to_dest_dir();
1036 }
1037
1038 static int handle_signal(void)
1039 {
1040         int sig, ret = next_signal();
1041
1042         if (ret <= 0)
1043                 goto out;
1044         sig = ret;
1045         switch (sig) {
1046         case SIGINT:
1047         case SIGTERM:
1048                 restart_create_process();
1049                 dss_kill(create_pid, SIGTERM, NULL);
1050                 dss_kill(remove_pid, SIGTERM, NULL);
1051                 ret = -E_SIGNAL;
1052                 break;
1053         case SIGHUP:
1054                 ret = handle_sighup();
1055                 break;
1056         case SIGCHLD:
1057                 ret = handle_sigchld();
1058                 break;
1059         }
1060 out:
1061         if (ret < 0)
1062                 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
1063         return ret;
1064 }
1065
1066 /*
1067  * We can not use rsync locally if the local user is different from the remote
1068  * user or if the src dir is not on the local host (or both).
1069  */
1070 static int use_rsync_locally(char *logname)
1071 {
1072         char *h = conf.remote_host_arg;
1073
1074         if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
1075                 return 0;
1076         if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
1077                 return 0;
1078         return 1;
1079 }
1080
1081 static int rename_resume_snap(int64_t creation_time)
1082 {
1083         struct snapshot_list sl = {.num_snapshots = 0};
1084         struct snapshot *s = NULL;
1085         char *new_name = incomplete_name(creation_time);
1086         int ret;
1087         const char *why;
1088
1089         ret = 0;
1090         if (conf.no_resume_given)
1091                 goto out;
1092         dss_get_snapshot_list(&sl);
1093         /*
1094          * Snapshot recycling: We first look at the newest snapshot. If this
1095          * snapshot happens to be incomplete, the last rsync process was
1096          * aborted and we reuse this one. Otherwise we look at snapshots which
1097          * could be removed (outdated and redundant snapshots) as candidates
1098          * for recycling. If no outdated/redundant snapshot exists, we check if
1099          * there is an orphaned snapshot, which likely is useless anyway.
1100          *
1101          * Only if no existing snapshot is suitable for recycling, we bite the
1102          * bullet and create a new one.
1103          */
1104         s = get_newest_snapshot(&sl);
1105         if (!s) /* no snapshots at all */
1106                 goto out;
1107         /* re-use last snapshot if it is incomplete */
1108         why = "aborted";
1109         if ((s->flags & SS_COMPLETE) == 0)
1110                 goto out;
1111         why = "outdated";
1112         s = find_outdated_snapshot(&sl);
1113         if (s)
1114                 goto out;
1115         why = "redundant";
1116         s = find_redundant_snapshot(&sl);
1117         if (s)
1118                 goto out;
1119         why = "orphaned";
1120         s = find_orphaned_snapshot(&sl);
1121 out:
1122         if (s) {
1123                 DSS_INFO_LOG("reusing %s snapshot %s\n", why, s->name);
1124                 ret = dss_rename(s->name, new_name);
1125         }
1126         if (ret >= 0)
1127                 DSS_NOTICE_LOG("creating new snapshot %s\n", new_name);
1128         free(new_name);
1129         free_snapshot_list(&sl);
1130         return ret;
1131 }
1132
1133 static void create_rsync_argv(char ***argv, int64_t *num)
1134 {
1135         char *logname;
1136         int i = 0, j;
1137         struct snapshot_list sl;
1138
1139         dss_get_snapshot_list(&sl);
1140         assert(!name_of_reference_snapshot);
1141         name_of_reference_snapshot = name_of_newest_complete_snapshot(&sl);
1142         free_snapshot_list(&sl);
1143
1144         *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
1145         (*argv)[i++] = dss_strdup("rsync");
1146         (*argv)[i++] = dss_strdup("-aq");
1147         (*argv)[i++] = dss_strdup("--delete");
1148         for (j = 0; j < conf.rsync_option_given; j++)
1149                 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
1150         if (name_of_reference_snapshot) {
1151                 DSS_INFO_LOG("using %s as reference\n", name_of_reference_snapshot);
1152                 (*argv)[i++] = make_message("--link-dest=../%s",
1153                         name_of_reference_snapshot);
1154         } else
1155                 DSS_INFO_LOG("no suitable reference snapshot found\n");
1156         logname = dss_logname();
1157         if (use_rsync_locally(logname))
1158                 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
1159         else
1160                 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
1161                         conf.remote_user_arg : logname,
1162                         conf.remote_host_arg, conf.source_dir_arg);
1163         free(logname);
1164         *num = get_current_time();
1165         (*argv)[i++] = incomplete_name(*num);
1166         (*argv)[i++] = NULL;
1167         for (j = 0; j < i; j++)
1168                 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
1169 }
1170
1171 static void free_rsync_argv(char **argv)
1172 {
1173         int i;
1174
1175         if (!argv)
1176                 return;
1177         for (i = 0; argv[i]; i++)
1178                 free(argv[i]);
1179         free(argv);
1180 }
1181
1182 static int create_snapshot(char **argv)
1183 {
1184         int ret, fds[3] = {0, 0, 0};
1185
1186         ret = rename_resume_snap(current_snapshot_creation_time);
1187         if (ret < 0)
1188                 return ret;
1189         ret = dss_exec(&create_pid, argv[0], argv, fds);
1190         if (ret < 0)
1191                 return ret;
1192         snapshot_creation_status = HS_RUNNING;
1193         return ret;
1194 }
1195
1196 static int select_loop(void)
1197 {
1198         int ret;
1199         /* check every 60 seconds for free disk space */
1200         struct timeval tv;
1201         char **rsync_argv = NULL;
1202
1203         for (;;) {
1204                 fd_set rfds;
1205                 struct timeval *tvp;
1206
1207                 if (remove_pid)
1208                         tvp = NULL; /* sleep until rm hook/process dies */
1209                 else { /* sleep one minute */
1210                         tv.tv_sec = 60;
1211                         tv.tv_usec = 0;
1212                         tvp = &tv;
1213                 }
1214                 FD_ZERO(&rfds);
1215                 FD_SET(signal_pipe, &rfds);
1216                 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
1217                 if (ret < 0)
1218                         goto out;
1219                 if (FD_ISSET(signal_pipe, &rfds)) {
1220                         ret = handle_signal();
1221                         if (ret < 0)
1222                                 goto out;
1223                 }
1224                 if (remove_pid)
1225                         continue;
1226                 if (snapshot_removal_status == HS_PRE_SUCCESS) {
1227                         ret = exec_rm();
1228                         if (ret < 0)
1229                                 goto out;
1230                         continue;
1231                 }
1232                 if (snapshot_removal_status == HS_SUCCESS) {
1233                         ret = post_remove_hook();
1234                         if (ret < 0)
1235                                 goto out;
1236                         continue;
1237                 }
1238                 ret = try_to_free_disk_space();
1239                 if (ret < 0)
1240                         goto out;
1241                 if (snapshot_removal_status != HS_READY) {
1242                         stop_create_process();
1243                         continue;
1244                 }
1245                 restart_create_process();
1246                 switch (snapshot_creation_status) {
1247                 case HS_READY:
1248                         if (!next_snapshot_is_due())
1249                                 continue;
1250                         ret = pre_create_hook();
1251                         if (ret < 0)
1252                                 goto out;
1253                         continue;
1254                 case HS_PRE_RUNNING:
1255                 case HS_RUNNING:
1256                 case HS_POST_RUNNING:
1257                         continue;
1258                 case HS_PRE_SUCCESS:
1259                         if (!name_of_reference_snapshot) {
1260                                 free_rsync_argv(rsync_argv);
1261                                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1262                         }
1263                         ret = create_snapshot(rsync_argv);
1264                         if (ret < 0)
1265                                 goto out;
1266                         continue;
1267                 case HS_NEEDS_RESTART:
1268                         if (!next_snapshot_is_due())
1269                                 continue;
1270                         ret = create_snapshot(rsync_argv);
1271                         if (ret < 0)
1272                                 goto out;
1273                         continue;
1274                 case HS_SUCCESS:
1275                         ret = post_create_hook();
1276                         if (ret < 0)
1277                                 goto out;
1278                         continue;
1279                 }
1280         }
1281 out:
1282         return ret;
1283 }
1284
1285 static void exit_hook(int exit_code)
1286 {
1287         int fds[3] = {0, 0, 0};
1288         char *argv[] = {conf.exit_hook_arg, dss_strerror(-exit_code), NULL};
1289         pid_t pid;
1290
1291         DSS_NOTICE_LOG("executing %s %s\n", argv[0], argv[1]);
1292         dss_exec(&pid, conf.exit_hook_arg, argv, fds);
1293 }
1294
1295 static void lock_dss_or_die(void)
1296 {
1297         char *config_file = get_config_file_name();
1298         int ret = lock_dss(config_file);
1299
1300         free(config_file);
1301         if (ret < 0) {
1302                 DSS_EMERG_LOG("failed to lock: %s\n", dss_strerror(-ret));
1303                 exit(EXIT_FAILURE);
1304         }
1305 }
1306
1307 static int com_run(void)
1308 {
1309         int ret;
1310
1311         lock_dss_or_die();
1312         if (conf.dry_run_given) {
1313                 DSS_ERROR_LOG("dry_run not supported by this command\n");
1314                 return -E_SYNTAX;
1315         }
1316         ret = install_sighandler(SIGHUP);
1317         if (ret < 0)
1318                 return ret;
1319         ret = select_loop();
1320         if (ret >= 0) /* impossible */
1321                 ret = -E_BUG;
1322         exit_hook(ret);
1323         return ret;
1324 }
1325
1326 static int com_prune(void)
1327 {
1328         int ret;
1329         struct snapshot_list sl;
1330         struct snapshot *victim;
1331         struct disk_space ds;
1332         const char *why;
1333
1334         lock_dss_or_die();
1335         ret = get_disk_space(".", &ds);
1336         if (ret < 0)
1337                 return ret;
1338         log_disk_space(&ds);
1339         dss_get_snapshot_list(&sl);
1340         why = "outdated";
1341         victim = find_outdated_snapshot(&sl);
1342         if (victim)
1343                 goto rm;
1344         why = "redundant";
1345         victim = find_redundant_snapshot(&sl);
1346         if (victim)
1347                 goto rm;
1348         ret = 0;
1349         goto out;
1350 rm:
1351         if (conf.dry_run_given) {
1352                 dss_msg("%s snapshot %s (interval = %i)\n",
1353                         why, victim->name, victim->interval);
1354                 ret = 0;
1355                 goto out;
1356         }
1357         ret = pre_remove_hook(victim, why);
1358         if (ret < 0)
1359                 goto out;
1360         if (snapshot_removal_status == HS_PRE_RUNNING) {
1361                 ret = wait_for_remove_process();
1362                 if (ret < 0)
1363                         goto out;
1364                 if (snapshot_removal_status != HS_PRE_SUCCESS)
1365                         goto out;
1366         }
1367         ret = exec_rm();
1368         if (ret < 0)
1369                 goto out;
1370         ret = wait_for_remove_process();
1371         if (ret < 0)
1372                 goto out;
1373         if (snapshot_removal_status != HS_SUCCESS)
1374                 goto out;
1375         ret = post_remove_hook();
1376         if (ret < 0)
1377                 goto out;
1378         if (snapshot_removal_status != HS_POST_RUNNING)
1379                 goto out;
1380         ret = wait_for_remove_process();
1381         if (ret < 0)
1382                 goto out;
1383         ret = 1;
1384 out:
1385         free_snapshot_list(&sl);
1386         return ret;
1387 }
1388
1389 static int com_create(void)
1390 {
1391         int ret, status;
1392         char **rsync_argv;
1393
1394         lock_dss_or_die();
1395         if (conf.dry_run_given) {
1396                 int i;
1397                 char *msg = NULL;
1398                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1399                 for (i = 0; rsync_argv[i]; i++) {
1400                         char *tmp = msg;
1401                         msg = make_message("%s%s%s", tmp? tmp : "",
1402                                 tmp? " " : "", rsync_argv[i]);
1403                         free(tmp);
1404                 }
1405                 free_rsync_argv(rsync_argv);
1406                 dss_msg("%s\n", msg);
1407                 free(msg);
1408                 return 1;
1409         }
1410         ret = pre_create_hook();
1411         if (ret < 0)
1412                 return ret;
1413         if (create_pid) {
1414                 ret = wait_for_process(create_pid, &status);
1415                 if (ret < 0)
1416                         return ret;
1417                 ret = handle_pre_create_hook_exit(status);
1418                 if (ret <= 0) /* error, or pre-create failed */
1419                         return ret;
1420         }
1421         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1422         ret = create_snapshot(rsync_argv);
1423         if (ret < 0)
1424                 goto out;
1425         ret = wait_for_process(create_pid, &status);
1426         if (ret < 0)
1427                 goto out;
1428         ret = handle_rsync_exit(status);
1429         if (ret < 0)
1430                 goto out;
1431         post_create_hook();
1432         if (create_pid)
1433                 ret = wait_for_process(create_pid, &status);
1434 out:
1435         free_rsync_argv(rsync_argv);
1436         return ret;
1437 }
1438
1439 static int com_ls(void)
1440 {
1441         int i;
1442         struct snapshot_list sl;
1443         struct snapshot *s;
1444
1445         dss_get_snapshot_list(&sl);
1446         FOR_EACH_SNAPSHOT(s, i, &sl) {
1447                 int64_t d = 0;
1448                 if (s->flags & SS_COMPLETE)
1449                         d = (s->completion_time - s->creation_time) / 60;
1450                 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1451         };
1452         free_snapshot_list(&sl);
1453         return 1;
1454 }
1455
1456 static int setup_signal_handling(void)
1457 {
1458         int ret;
1459
1460         DSS_INFO_LOG("setting up signal handlers\n");
1461         signal_pipe = signal_init(); /* always successful */
1462         ret = install_sighandler(SIGINT);
1463         if (ret < 0)
1464                 return ret;
1465         ret = install_sighandler(SIGTERM);
1466         if (ret < 0)
1467                 return ret;
1468         return install_sighandler(SIGCHLD);
1469 }
1470
1471 /**
1472  * The main function of dss.
1473  *
1474  * \param argc Usual argument count.
1475  * \param argv Usual argument vector.
1476  */
1477 int main(int argc, char **argv)
1478 {
1479         int ret;
1480         struct cmdline_parser_params params = {
1481                 .override = 0,
1482                 .initialize = 1,
1483                 .check_required = 0,
1484                 .check_ambiguity = 0,
1485                 .print_errors = 1
1486         };
1487
1488         cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1489         ret = parse_config_file(0);
1490         if (ret < 0)
1491                 goto out;
1492         if (ret == 0) { /* no config file given */
1493                 /*
1494                  * Parse the command line options again, but this time check
1495                  * that all required options are given.
1496                  */
1497                 params = (struct cmdline_parser_params) {
1498                         .override = 1,
1499                         .initialize = 1,
1500                         .check_required = 1,
1501                         .check_ambiguity = 1,
1502                         .print_errors = 1
1503                 };
1504                 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1505         }
1506         if (conf.daemon_given)
1507                 daemon_init();
1508         ret = change_to_dest_dir();
1509         if (ret < 0)
1510                 goto out;
1511         dump_dss_config("startup");
1512         ret = setup_signal_handling();
1513         if (ret < 0)
1514                 goto out;
1515         ret = call_command_handler();
1516 out:
1517         if (ret < 0)
1518                 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1519         exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1520 }