dss.c

   1 /*
   2  * Copyright (C) 2008-2011 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6 #include <string.h>
   7 #include <stdlib.h>
   8 #include <stdarg.h>
   9 #include <assert.h>
  10 #include <errno.h>
  11 #include <sys/types.h>
  12 #include <signal.h>
  13 #include <ctype.h>
  14 #include <sys/stat.h>
  15 #include <unistd.h>
  16 #include <inttypes.h>
  17 #include <sys/time.h>
  18 #include <time.h>
  19 #include <sys/wait.h>
  20 #include <fnmatch.h>
  21 #include <limits.h>
  22
  23
  24 #include "gcc-compat.h"
  25 #include "cmdline.h"
  26 #include "log.h"
  27 #include "string.h"
  28 #include "error.h"
  29 #include "fd.h"
  30 #include "exec.h"
  31 #include "daemon.h"
  32 #include "signal.h"
  33 #include "df.h"
  34 #include "time.h"
  35 #include "snap.h"
  36 #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;
 535         struct snapshot *s;
 536         FOR_EACH_SNAPSHOT(s, i, sl) {
 537                 if (snapshot_is_being_created(s))
 538                         continue;
 539                 if (is_reference_snapshot(s))
 540                         continue;
 541                 DSS_INFO_LOG(("oldest removable snapshot: %s\n", s->name));
 542                 return s;
 543         }
 544         return NULL;
 545 }
 546
 547 static int rename_incomplete_snapshot(int64_t start)
 548 {
 549         char *old_name;
 550         int ret;
 551
 552         free(path_to_last_complete_snapshot);
 553         ret = complete_name(start, get_current_time(),
 554                 &path_to_last_complete_snapshot);
 555         if (ret < 0)
 556                 return ret;
 557         old_name = incomplete_name(start);
 558         ret = dss_rename(old_name, path_to_last_complete_snapshot);
 559         if (ret >= 0)
 560                 DSS_NOTICE_LOG(("%s -> %s\n", old_name,
 561                         path_to_last_complete_snapshot));
 562         free(old_name);
 563         return ret;
 564 }
 565
 566 static int try_to_free_disk_space(void)
 567 {
 568         int ret;
 569         struct snapshot_list sl;
 570         struct snapshot *victim;
 571         struct timeval now;
 572         const char *why;
 573         int low_disk_space;
 574
 575         ret = disk_space_low(NULL);
 576         if (ret < 0)
 577                 return ret;
 578         low_disk_space = ret;
 579         gettimeofday(&now, NULL);
 580         if (tv_diff(&next_removal_check, &now, NULL) > 0)
 581                 return 0;
 582         if (!low_disk_space) {
 583                 if (conf.keep_redundant_given)
 584                         return 0;
 585                 if (snapshot_creation_status != HS_READY)
 586                         return 0;
 587                 if (next_snapshot_is_due())
 588                         return 0;
 589         }
 590         dss_get_snapshot_list(&sl);
 591         ret = 0;
 592         if (!low_disk_space && sl.num_snapshots <= 1)
 593                 goto out;
 594         why = "outdated";
 595         victim = find_outdated_snapshot(&sl);
 596         if (victim)
 597                 goto remove;
 598         why = "redundant";
 599         victim = find_redundant_snapshot(&sl);
 600         if (victim)
 601                 goto remove;
 602         /* try harder only if disk space is low */
 603         if (!low_disk_space)
 604                 goto out;
 605         why = "orphaned";
 606         victim = find_orphaned_snapshot(&sl);
 607         if (victim)
 608                 goto remove;
 609         DSS_WARNING_LOG(("disk space low and nothing obvious to remove\n"));
 610         victim = find_oldest_removable_snapshot(&sl);
 611         if (victim)
 612                 goto remove;
 613         DSS_CRIT_LOG(("uhuhu: disk space low and nothing to remove\n"));
 614         ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
 615         goto out;
 616 remove:
 617         pre_remove_hook(victim, why);
 618 out:
 619         free_snapshot_list(&sl);
 620         return ret;
 621 }
 622
 623 static void post_create_hook(void)
 624 {
 625         char *cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
 626                 conf.dest_dir_arg, path_to_last_complete_snapshot);
 627         DSS_NOTICE_LOG(("executing %s\n", cmd));
 628         dss_exec_cmdline_pid(&create_pid, cmd);
 629         free(cmd);
 630         snapshot_creation_status = HS_POST_RUNNING;
 631 }
 632
 633 static void post_remove_hook(void)
 634 {
 635         char *cmd;
 636         struct snapshot *s = snapshot_currently_being_removed;
 637
 638         assert(s);
 639
 640         cmd = make_message("%s %s/%s", conf.post_remove_hook_arg,
 641                 conf.dest_dir_arg, s->name);
 642         DSS_NOTICE_LOG(("executing %s\n", cmd));
 643         dss_exec_cmdline_pid(&remove_pid, cmd);
 644         free(cmd);
 645         snapshot_removal_status = HS_POST_RUNNING;
 646 }
 647
 648 static void dss_kill(pid_t pid, int sig, const char *msg)
 649 {
 650         const char *signame, *process_name;
 651
 652         if (pid == 0)
 653                 return;
 654         switch (sig) {
 655         case SIGTERM: signame = "TERM"; break;
 656         case SIGSTOP: signame = "STOP"; break;
 657         case SIGCONT: signame = "CONT"; break;
 658         default: signame = "????";
 659         }
 660
 661         if (pid == create_pid)
 662                 process_name = "create";
 663         else if (pid == remove_pid)
 664                 process_name = "remove";
 665         else process_name = "??????";
 666
 667         if (msg)
 668                 DSS_INFO_LOG(("%s\n", msg));
 669         DSS_DEBUG_LOG(("sending signal %d (%s) to pid %d (%s process)\n",
 670                 sig, signame, (int)pid, process_name));
 671         if (kill(pid, sig) >= 0)
 672                 return;
 673         DSS_INFO_LOG(("failed to send signal %d (%s) to pid %d (%s process)\n",
 674                 sig, signame, (int)pid, process_name));
 675 }
 676
 677 static void stop_create_process(void)
 678 {
 679         if (create_process_stopped)
 680                 return;
 681         dss_kill(create_pid, SIGSTOP, "suspending create process");
 682         create_process_stopped = 1;
 683 }
 684
 685 static void restart_create_process(void)
 686 {
 687         if (!create_process_stopped)
 688                 return;
 689         dss_kill(create_pid, SIGCONT, "resuming create process");
 690         create_process_stopped = 0;
 691 }
 692
 693 /**
 694  * Print a log message about the exit status of a child.
 695  */
 696 static void log_termination_msg(pid_t pid, int status)
 697 {
 698         if (WIFEXITED(status))
 699                 DSS_INFO_LOG(("child %i exited. Exit status: %i\n", (int)pid,
 700                         WEXITSTATUS(status)));
 701         else if (WIFSIGNALED(status))
 702                 DSS_NOTICE_LOG(("child %i was killed by signal %i\n", (int)pid,
 703                         WTERMSIG(status)));
 704         else
 705                 DSS_WARNING_LOG(("child %i terminated abormally\n", (int)pid));
 706 }
 707
 708 static int wait_for_process(pid_t pid, int *status)
 709 {
 710         int ret;
 711
 712         DSS_DEBUG_LOG(("Waiting for process %d to terminate\n", (int)pid));
 713         for (;;) {
 714                 fd_set rfds;
 715
 716                 FD_ZERO(&rfds);
 717                 FD_SET(signal_pipe, &rfds);
 718                 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
 719                 if (ret < 0)
 720                         break;
 721                 ret = next_signal();
 722                 if (!ret)
 723                         continue;
 724                 if (ret == SIGCHLD) {
 725                         ret = waitpid(pid, status, 0);
 726                         if (ret >= 0)
 727                                 break;
 728                         if (errno != EINTR) { /* error */
 729                                 ret = -ERRNO_TO_DSS_ERROR(errno);
 730                                 break;
 731                         }
 732                 }
 733                 /* SIGINT or SIGTERM */
 734                 dss_kill(pid, SIGTERM, "killing child process");
 735         }
 736         if (ret < 0)
 737                 DSS_ERROR_LOG(("failed to wait for process %d\n", (int)pid));
 738         else
 739                 log_termination_msg(pid, *status);
 740         return ret;
 741 }
 742
 743 static void handle_pre_remove_exit(int status)
 744 {
 745         if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 746                 snapshot_removal_status = HS_READY;
 747                 gettimeofday(&next_removal_check, NULL);
 748                 next_removal_check.tv_sec += 60;
 749                 return;
 750         }
 751         snapshot_removal_status = HS_PRE_SUCCESS;
 752 }
 753
 754 static int handle_rm_exit(int status)
 755 {
 756         if (!WIFEXITED(status)) {
 757                 snapshot_removal_status = HS_READY;
 758                 return -E_INVOLUNTARY_EXIT;
 759         }
 760         if (WEXITSTATUS(status)) {
 761                 snapshot_removal_status = HS_READY;
 762                 return -E_BAD_EXIT_CODE;
 763         }
 764         snapshot_removal_status = HS_SUCCESS;
 765         return 1;
 766 }
 767
 768 static void handle_post_remove_exit(void)
 769 {
 770         snapshot_removal_status = HS_READY;
 771 }
 772
 773 static int handle_remove_exit(int status)
 774 {
 775         int ret;
 776         struct snapshot *s = snapshot_currently_being_removed;
 777
 778         assert(s);
 779         switch (snapshot_removal_status) {
 780         case HS_PRE_RUNNING:
 781                 handle_pre_remove_exit(status);
 782                 ret = 1;
 783                 break;
 784         case HS_RUNNING:
 785                 ret = handle_rm_exit(status);
 786                 break;
 787         case HS_POST_RUNNING:
 788                 handle_post_remove_exit();
 789                 ret = 1;
 790                 break;
 791         default:
 792                 ret = -E_BUG;
 793         }
 794         if (snapshot_removal_status == HS_READY) {
 795                 free(s->name);
 796                 free(s);
 797                 snapshot_currently_being_removed = NULL;
 798         }
 799         remove_pid = 0;
 800         return ret;
 801 }
 802
 803 static int wait_for_remove_process(void)
 804 {
 805         int status, ret;
 806
 807         assert(remove_pid);
 808         assert(
 809                 snapshot_removal_status == HS_PRE_RUNNING ||
 810                 snapshot_removal_status == HS_RUNNING ||
 811                 snapshot_removal_status == HS_POST_RUNNING
 812         );
 813         ret = wait_for_process(remove_pid, &status);
 814         if (ret < 0)
 815                 return ret;
 816         return handle_remove_exit(status);
 817 }
 818
 819 static int handle_rsync_exit(int status)
 820 {
 821         int es, ret;
 822
 823         if (!WIFEXITED(status)) {
 824                 DSS_ERROR_LOG(("rsync process %d died involuntary\n", (int)create_pid));
 825                 ret = -E_INVOLUNTARY_EXIT;
 826                 snapshot_creation_status = HS_READY;
 827                 goto out;
 828         }
 829         es = WEXITSTATUS(status);
 830         /*
 831          * Restart rsync on non-fatal errors:
 832          * 12: Error in rsync protocol data stream
 833          * 13: Errors with program diagnostics
 834          */
 835         if (es == 12 || es == 13) {
 836                 DSS_WARNING_LOG(("rsync process %d returned %d -- restarting\n",
 837                         (int)create_pid, es));
 838                 snapshot_creation_status = HS_NEEDS_RESTART;
 839                 next_snapshot_time = get_current_time() + 60;
 840                 ret = 1;
 841                 goto out;
 842         }
 843         if (es != 0 && es != 23 && es != 24) {
 844                 DSS_ERROR_LOG(("rsync process %d returned %d\n", (int)create_pid, es));
 845                 ret = -E_BAD_EXIT_CODE;
 846                 snapshot_creation_status = HS_READY;
 847                 goto out;
 848         }
 849         ret = rename_incomplete_snapshot(current_snapshot_creation_time);
 850         if (ret < 0)
 851                 goto out;
 852         snapshot_creation_status = HS_SUCCESS;
 853         free(name_of_reference_snapshot);
 854         name_of_reference_snapshot = NULL;
 855 out:
 856         create_process_stopped = 0;
 857         return ret;
 858 }
 859
 860 static int handle_pre_create_hook_exit(int status)
 861 {
 862         int es, ret;
 863         static int warn_count;
 864
 865         if (!WIFEXITED(status)) {
 866                 snapshot_creation_status = HS_READY;
 867                 ret = -E_INVOLUNTARY_EXIT;
 868                 goto out;
 869         }
 870         es = WEXITSTATUS(status);
 871         if (es) {
 872                 if (!warn_count--) {
 873                         DSS_NOTICE_LOG(("pre_create_hook %s returned %d\n",
 874                                 conf.pre_create_hook_arg, es));
 875                         DSS_NOTICE_LOG(("deferring snapshot creation...\n"));
 876                         warn_count = 60; /* warn only once per hour */
 877                 }
 878                 next_snapshot_time = get_current_time() + 60;
 879                 snapshot_creation_status = HS_READY;
 880                 ret = 0;
 881                 goto out;
 882         }
 883         warn_count = 0;
 884         snapshot_creation_status = HS_PRE_SUCCESS;
 885         ret = 1;
 886 out:
 887         return ret;
 888 }
 889
 890 static int handle_sigchld(void)
 891 {
 892         pid_t pid;
 893         int status, ret = reap_child(&pid, &status);
 894
 895         if (ret <= 0)
 896                 return ret;
 897
 898         if (pid == create_pid) {
 899                 switch (snapshot_creation_status) {
 900                 case HS_PRE_RUNNING:
 901                         ret = handle_pre_create_hook_exit(status);
 902                         break;
 903                 case HS_RUNNING:
 904                         ret = handle_rsync_exit(status);
 905                         break;
 906                 case HS_POST_RUNNING:
 907                         snapshot_creation_status = HS_READY;
 908                         ret = 1;
 909                         break;
 910                 default:
 911                         DSS_EMERG_LOG(("BUG: create can't die in status %d\n",
 912                                 snapshot_creation_status));
 913                         return -E_BUG;
 914                 }
 915                 create_pid = 0;
 916                 return ret;
 917         }
 918         if (pid == remove_pid) {
 919                 ret = handle_remove_exit(status);
 920                 if (ret < 0)
 921                         return ret;
 922                 return ret;
 923         }
 924         DSS_EMERG_LOG(("BUG: unknown process %d died\n", (int)pid));
 925         return -E_BUG;
 926 }
 927
 928 static int check_config(void)
 929 {
 930         if (conf.unit_interval_arg <= 0) {
 931                 DSS_ERROR_LOG(("bad unit interval: %i\n", conf.unit_interval_arg));
 932                 return -E_INVALID_NUMBER;
 933         }
 934         DSS_DEBUG_LOG(("unit interval: %i day(s)\n", conf.unit_interval_arg));
 935         if (conf.num_intervals_arg <= 0) {
 936                 DSS_ERROR_LOG(("bad number of intervals  %i\n", conf.num_intervals_arg));
 937                 return -E_INVALID_NUMBER;
 938         }
 939         DSS_DEBUG_LOG(("number of intervals: %i\n", conf.num_intervals_arg));
 940         return 1;
 941 }
 942
 943 /*
 944  * Returns < 0 on errors, 0 if no config file is given and > 0 if the config
 945  * file was read successfully.
 946  */
 947 static int parse_config_file(int override)
 948 {
 949         int ret, config_file_exists;
 950         char *config_file = get_config_file_name();
 951         struct stat statbuf;
 952         char *old_logfile_arg = NULL;
 953         int old_daemon_given = 0;
 954
 955         if (override) { /* SIGHUP */
 956                 if (conf.logfile_given)
 957                         old_logfile_arg = dss_strdup(conf.logfile_arg);
 958                 old_daemon_given = conf.daemon_given;
 959         }
 960
 961         config_file_exists = !stat(config_file, &statbuf);
 962         if (!config_file_exists && conf.config_file_given) {
 963                 ret = -ERRNO_TO_DSS_ERROR(errno);
 964                 DSS_ERROR_LOG(("failed to stat config file %s\n", config_file));
 965                 goto out;
 966         }
 967         if (config_file_exists) {
 968                 struct cmdline_parser_params params;
 969                 params.override = override;
 970                 params.initialize = 0;
 971                 params.check_required = 1;
 972                 params.check_ambiguity = 0;
 973                 params.print_errors = 1;
 974                 if (override) { /* invalidate all rsync options */
 975                         int i;
 976
 977                         for (i = 0; i < conf.rsync_option_given; i++) {
 978                                 free(conf.rsync_option_arg[i]);
 979                                 conf.rsync_option_arg[i] = NULL;
 980                         }
 981                         conf.rsync_option_given = 0;
 982                 }
 983                 cmdline_parser_config_file(config_file, &conf, &params);
 984         }
 985         ret = check_config();
 986         if (ret < 0)
 987                 goto out;
 988         if (override) {
 989                 /* don't change daemon mode on SIGHUP */
 990                 conf.daemon_given = old_daemon_given;
 991                 close_log(logfile);
 992                 logfile = NULL;
 993                 if (conf.logfile_given)
 994                         free(old_logfile_arg);
 995                 else if (conf.daemon_given) { /* re-use old logfile */
 996                         conf.logfile_arg = old_logfile_arg;
 997                         conf.logfile_given = 1;
 998                 }
 999         }
1000         if (conf.logfile_given && conf.run_given && conf.daemon_given) {
1001                 logfile = open_log(conf.logfile_arg);
1002                 log_welcome(conf.loglevel_arg);
1003         }
1004         DSS_DEBUG_LOG(("loglevel: %d\n", conf.loglevel_arg));
1005         ret = config_file_exists;
1006 out:
1007         free(config_file);
1008         if (ret < 0)
1009                 DSS_EMERG_LOG(("%s\n", dss_strerror(-ret)));
1010         return ret;
1011 }
1012
1013 static int change_to_dest_dir(void)
1014 {
1015         DSS_INFO_LOG(("changing cwd to %s\n", conf.dest_dir_arg));
1016         return dss_chdir(conf.dest_dir_arg);
1017 }
1018
1019 static int handle_sighup(void)
1020 {
1021         int ret;
1022
1023         DSS_NOTICE_LOG(("SIGHUP, re-reading config\n"));
1024         dump_dss_config("old");
1025         ret = parse_config_file(1);
1026         if (ret < 0)
1027                 return ret;
1028         dump_dss_config("reloaded");
1029         invalidate_next_snapshot_time();
1030         return change_to_dest_dir();
1031 }
1032
1033 static int handle_signal(void)
1034 {
1035         int sig, ret = next_signal();
1036
1037         if (ret <= 0)
1038                 goto out;
1039         sig = ret;
1040         switch (sig) {
1041         case SIGINT:
1042         case SIGTERM:
1043                 restart_create_process();
1044                 dss_kill(create_pid, SIGTERM, NULL);
1045                 dss_kill(remove_pid, SIGTERM, NULL);
1046                 ret = -E_SIGNAL;
1047                 break;
1048         case SIGHUP:
1049                 ret = handle_sighup();
1050                 break;
1051         case SIGCHLD:
1052                 ret = handle_sigchld();
1053                 break;
1054         }
1055 out:
1056         if (ret < 0)
1057                 DSS_ERROR_LOG(("%s\n", dss_strerror(-ret)));
1058         return ret;
1059 }
1060
1061 /*
1062  * We can not use rsync locally if the local user is different from the remote
1063  * user or if the src dir is not on the local host (or both).
1064  */
1065 static int use_rsync_locally(char *logname)
1066 {
1067         char *h = conf.remote_host_arg;
1068
1069         if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
1070                 return 0;
1071         if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
1072                 return 0;
1073         return 1;
1074 }
1075
1076 static int rename_resume_snap(int64_t creation_time)
1077 {
1078         struct snapshot_list sl;
1079         struct snapshot *s = NULL;
1080         char *new_name = incomplete_name(creation_time);
1081         int ret;
1082         const char *why;
1083
1084         sl.num_snapshots = 0;
1085
1086         ret = 0;
1087         if (conf.no_resume_given)
1088                 goto out;
1089         dss_get_snapshot_list(&sl);
1090         /*
1091          * Snapshot recycling: We first look at the newest snapshot. If this
1092          * snapshot happens to be incomplete, the last rsync process was
1093          * aborted and we reuse this one. Otherwise we look at snapshots which
1094          * could be removed (outdated and redundant snapshots) as candidates
1095          * for recycling. If no outdated/redundant snapshot exists, we check if
1096          * there is an orphaned snapshot, which likely is useless anyway.
1097          *
1098          * Only if no existing snapshot is suitable for recycling, we bite the
1099          * bullet and create a new one.
1100          */
1101         s = get_newest_snapshot(&sl);
1102         if (!s) /* no snapshots at all */
1103                 goto out;
1104         /* re-use last snapshot if it is incomplete */
1105         why = "aborted";
1106         if ((s->flags & SS_COMPLETE) == 0)
1107                 goto out;
1108         why = "outdated";
1109         s = find_outdated_snapshot(&sl);
1110         if (s)
1111                 goto out;
1112         why = "redundant";
1113         s = find_redundant_snapshot(&sl);
1114         if (s)
1115                 goto out;
1116         why = "orphaned";
1117         s = find_orphaned_snapshot(&sl);
1118 out:
1119         if (s) {
1120                 DSS_INFO_LOG(("reusing %s snapshot %s\n", why, s->name));
1121                 ret = dss_rename(s->name, new_name);
1122         }
1123         if (ret >= 0)
1124                 DSS_NOTICE_LOG(("creating new snapshot %s\n", new_name));
1125         free(new_name);
1126         free_snapshot_list(&sl);
1127         return ret;
1128 }
1129
1130 static void create_rsync_argv(char ***argv, int64_t *num)
1131 {
1132         char *logname;
1133         int i = 0, j;
1134         struct snapshot_list sl;
1135
1136         dss_get_snapshot_list(&sl);
1137         assert(!name_of_reference_snapshot);
1138         name_of_reference_snapshot = name_of_newest_complete_snapshot(&sl);
1139         free_snapshot_list(&sl);
1140
1141         *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
1142         (*argv)[i++] = dss_strdup("rsync");
1143         (*argv)[i++] = dss_strdup("-aq");
1144         (*argv)[i++] = dss_strdup("--delete");
1145         for (j = 0; j < conf.rsync_option_given; j++)
1146                 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
1147         if (name_of_reference_snapshot) {
1148                 DSS_INFO_LOG(("using %s as reference\n", name_of_reference_snapshot));
1149                 (*argv)[i++] = make_message("--link-dest=../%s",
1150                         name_of_reference_snapshot);
1151         } else
1152                 DSS_INFO_LOG(("no suitable reference snapshot found\n"));
1153         logname = dss_logname();
1154         if (use_rsync_locally(logname))
1155                 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
1156         else
1157                 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
1158                         conf.remote_user_arg : logname,
1159                         conf.remote_host_arg, conf.source_dir_arg);
1160         free(logname);
1161         *num = get_current_time();
1162         (*argv)[i++] = incomplete_name(*num);
1163         (*argv)[i++] = NULL;
1164         for (j = 0; j < i; j++)
1165                 DSS_DEBUG_LOG(("argv[%d] = %s\n", j, (*argv)[j]));
1166 }
1167
1168 static void free_rsync_argv(char **argv)
1169 {
1170         int i;
1171
1172         if (!argv)
1173                 return;
1174         for (i = 0; argv[i]; i++)
1175                 free(argv[i]);
1176         free(argv);
1177 }
1178
1179 static int create_snapshot(char **argv)
1180 {
1181         int ret;
1182
1183         ret = rename_resume_snap(current_snapshot_creation_time);
1184         if (ret < 0)
1185                 return ret;
1186         dss_exec(&create_pid, argv[0], argv);
1187         snapshot_creation_status = HS_RUNNING;
1188         return ret;
1189 }
1190
1191 static int select_loop(void)
1192 {
1193         int ret;
1194         /* check every 60 seconds for free disk space */
1195         struct timeval tv;
1196         char **rsync_argv = NULL;
1197
1198         for (;;) {
1199                 fd_set rfds;
1200                 struct timeval *tvp;
1201
1202                 if (remove_pid)
1203                         tvp = NULL; /* sleep until rm hook/process dies */
1204                 else { /* sleep one minute */
1205                         tv.tv_sec = 60;
1206                         tv.tv_usec = 0;
1207                         tvp = &tv;
1208                 }
1209                 FD_ZERO(&rfds);
1210                 FD_SET(signal_pipe, &rfds);
1211                 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
1212                 if (ret < 0)
1213                         goto out;
1214                 if (FD_ISSET(signal_pipe, &rfds)) {
1215                         ret = handle_signal();
1216                         if (ret < 0)
1217                                 goto out;
1218                 }
1219                 if (remove_pid)
1220                         continue;
1221                 if (snapshot_removal_status == HS_PRE_SUCCESS) {
1222                         ret = exec_rm();
1223                         if (ret < 0)
1224                                 goto out;
1225                         continue;
1226                 }
1227                 if (snapshot_removal_status == HS_SUCCESS) {
1228                         post_remove_hook();
1229                         continue;
1230                 }
1231                 ret = try_to_free_disk_space();
1232                 if (ret < 0)
1233                         goto out;
1234                 if (snapshot_removal_status != HS_READY) {
1235                         stop_create_process();
1236                         continue;
1237                 }
1238                 restart_create_process();
1239                 switch (snapshot_creation_status) {
1240                 case HS_READY:
1241                         if (!next_snapshot_is_due())
1242                                 continue;
1243                         pre_create_hook();
1244                         continue;
1245                 case HS_PRE_RUNNING:
1246                 case HS_RUNNING:
1247                 case HS_POST_RUNNING:
1248                         continue;
1249                 case HS_PRE_SUCCESS:
1250                         if (!name_of_reference_snapshot) {
1251                                 free_rsync_argv(rsync_argv);
1252                                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1253                         }
1254                         ret = create_snapshot(rsync_argv);
1255                         if (ret < 0)
1256                                 goto out;
1257                         continue;
1258                 case HS_NEEDS_RESTART:
1259                         if (!next_snapshot_is_due())
1260                                 continue;
1261                         ret = create_snapshot(rsync_argv);
1262                         if (ret < 0)
1263                                 goto out;
1264                         continue;
1265                 case HS_SUCCESS:
1266                         post_create_hook();
1267                         continue;
1268                 }
1269         }
1270 out:
1271         return ret;
1272 }
1273
1274 static void exit_hook(int exit_code)
1275 {
1276         char *argv[3];
1277         pid_t pid;
1278
1279         argv[0] = conf.exit_hook_arg;
1280         argv[1] = dss_strerror(-exit_code);
1281         argv[2] = NULL;
1282
1283         DSS_NOTICE_LOG(("executing %s %s\n", argv[0], argv[1]));
1284         dss_exec(&pid, conf.exit_hook_arg, argv);
1285 }
1286
1287 static void lock_dss_or_die(void)
1288 {
1289         char *config_file = get_config_file_name();
1290         int ret = lock_dss(config_file);
1291
1292         free(config_file);
1293         if (ret < 0) {
1294                 DSS_EMERG_LOG(("failed to lock: %s\n", dss_strerror(-ret)));
1295                 exit(EXIT_FAILURE);
1296         }
1297 }
1298
1299 static int com_run(void)
1300 {
1301         int ret;
1302
1303         lock_dss_or_die();
1304         if (conf.dry_run_given) {
1305                 DSS_ERROR_LOG(("dry_run not supported by this command\n"));
1306                 return -E_SYNTAX;
1307         }
1308         ret = install_sighandler(SIGHUP);
1309         if (ret < 0)
1310                 return ret;
1311         ret = select_loop();
1312         if (ret >= 0) /* impossible */
1313                 ret = -E_BUG;
1314         exit_hook(ret);
1315         return ret;
1316 }
1317
1318 static int com_prune(void)
1319 {
1320         int ret;
1321         struct snapshot_list sl;
1322         struct snapshot *victim;
1323         struct disk_space ds;
1324         const char *why;
1325
1326         lock_dss_or_die();
1327         ret = get_disk_space(".", &ds);
1328         if (ret < 0)
1329                 return ret;
1330         log_disk_space(&ds);
1331         dss_get_snapshot_list(&sl);
1332         why = "outdated";
1333         victim = find_outdated_snapshot(&sl);
1334         if (victim)
1335                 goto rm;
1336         why = "redundant";
1337         victim = find_redundant_snapshot(&sl);
1338         if (victim)
1339                 goto rm;
1340         ret = 0;
1341         goto out;
1342 rm:
1343         if (conf.dry_run_given) {
1344                 dss_msg("%s snapshot %s (interval = %i)\n",
1345                         why, victim->name, victim->interval);
1346                 ret = 0;
1347                 goto out;
1348         }
1349         pre_remove_hook(victim, why);
1350         if (snapshot_removal_status == HS_PRE_RUNNING) {
1351                 ret = wait_for_remove_process();
1352                 if (ret < 0)
1353                         goto out;
1354                 if (snapshot_removal_status != HS_PRE_SUCCESS)
1355                         goto out;
1356         }
1357         ret = exec_rm();
1358         if (ret < 0)
1359                 goto out;
1360         ret = wait_for_remove_process();
1361         if (ret < 0)
1362                 goto out;
1363         if (snapshot_removal_status != HS_SUCCESS)
1364                 goto out;
1365         post_remove_hook();
1366         if (snapshot_removal_status != HS_POST_RUNNING)
1367                 goto out;
1368         ret = wait_for_remove_process();
1369         if (ret < 0)
1370                 goto out;
1371         ret = 1;
1372 out:
1373         free_snapshot_list(&sl);
1374         return ret;
1375 }
1376
1377 static int com_create(void)
1378 {
1379         int ret, status;
1380         char **rsync_argv;
1381
1382         lock_dss_or_die();
1383         if (conf.dry_run_given) {
1384                 int i;
1385                 char *msg = NULL;
1386                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1387                 for (i = 0; rsync_argv[i]; i++) {
1388                         char *tmp = msg;
1389                         msg = make_message("%s%s%s", tmp? tmp : "",
1390                                 tmp? " " : "", rsync_argv[i]);
1391                         free(tmp);
1392                 }
1393                 free_rsync_argv(rsync_argv);
1394                 dss_msg("%s\n", msg);
1395                 free(msg);
1396                 return 1;
1397         }
1398         pre_create_hook();
1399         if (create_pid) {
1400                 ret = wait_for_process(create_pid, &status);
1401                 if (ret < 0)
1402                         return ret;
1403                 ret = handle_pre_create_hook_exit(status);
1404                 if (ret <= 0) /* error, or pre-create failed */
1405                         return ret;
1406         }
1407         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1408         ret = create_snapshot(rsync_argv);
1409         if (ret < 0)
1410                 goto out;
1411         ret = wait_for_process(create_pid, &status);
1412         if (ret < 0)
1413                 goto out;
1414         ret = handle_rsync_exit(status);
1415         if (ret < 0)
1416                 goto out;
1417         post_create_hook();
1418         if (create_pid)
1419                 ret = wait_for_process(create_pid, &status);
1420 out:
1421         free_rsync_argv(rsync_argv);
1422         return ret;
1423 }
1424
1425 static int com_ls(void)
1426 {
1427         int i;
1428         struct snapshot_list sl;
1429         struct snapshot *s;
1430
1431         dss_get_snapshot_list(&sl);
1432         FOR_EACH_SNAPSHOT(s, i, &sl) {
1433                 int64_t d = 0;
1434                 if (s->flags & SS_COMPLETE)
1435                         d = (s->completion_time - s->creation_time) / 60;
1436                 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1437         };
1438         free_snapshot_list(&sl);
1439         return 1;
1440 }
1441
1442 static int setup_signal_handling(void)
1443 {
1444         int ret;
1445
1446         DSS_INFO_LOG(("setting up signal handlers\n"));
1447         signal_pipe = signal_init(); /* always successful */
1448         ret = install_sighandler(SIGINT);
1449         if (ret < 0)
1450                 return ret;
1451         ret = install_sighandler(SIGTERM);
1452         if (ret < 0)
1453                 return ret;
1454         return install_sighandler(SIGCHLD);
1455 }
1456
1457 /**
1458  * The main function of dss.
1459  *
1460  * \param argc Usual argument count.
1461  * \param argv Usual argument vector.
1462  */
1463 int main(int argc, char **argv)
1464 {
1465         int ret;
1466         struct cmdline_parser_params params;
1467
1468         params.override = 0;
1469         params.initialize = 1;
1470         params.check_required = 0;
1471         params.check_ambiguity = 0;
1472         params.print_errors = 1;
1473
1474         cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1475         ret = parse_config_file(0);
1476         if (ret < 0)
1477                 goto out;
1478         if (ret == 0) { /* no config file given */
1479                 /*
1480                  * Parse the command line options again, but this time check
1481                  * that all required options are given.
1482                  */
1483                 struct cmdline_parser_params params;
1484                 params.override = 1;
1485                 params.initialize = 1;
1486                 params.check_required = 1;
1487                 params.check_ambiguity = 1;
1488                 params.print_errors = 1;
1489                 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1490         }
1491         if (conf.daemon_given)
1492                 daemon_init();
1493         ret = change_to_dest_dir();
1494         if (ret < 0)
1495                 goto out;
1496         dump_dss_config("startup");
1497         ret = setup_signal_handling();
1498         if (ret < 0)
1499                 goto out;
1500         ret = call_command_handler();
1501 out:
1502         if (ret < 0)
1503                 DSS_EMERG_LOG(("%s\n", dss_strerror(-ret)));
1504         exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1505 }