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