dss.c

   1 /*
   2  * Copyright (C) 2008-2010 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6 #include <string.h>
   7 #include <stdlib.h>
   8 #include <stdarg.h>
   9 #include <assert.h>
  10 #include <errno.h>
  11 #include <sys/types.h>
  12 #include <signal.h>
  13 #include <ctype.h>
  14 #include <sys/stat.h>
  15 #include <unistd.h>
  16 #include <inttypes.h>
  17 #include <sys/time.h>
  18 #include <time.h>
  19 #include <sys/wait.h>
  20 #include <fnmatch.h>
  21 #include <limits.h>
  22
  23
  24 #include "gcc-compat.h"
  25 #include "cmdline.h"
  26 #include "log.h"
  27 #include "string.h"
  28 #include "error.h"
  29 #include "fd.h"
  30 #include "exec.h"
  31 #include "daemon.h"
  32 #include "signal.h"
  33 #include "df.h"
  34 #include "time.h"
  35 #include "snap.h"
  36 #include "ipc.h"
  37
  38 /** Command line and config file options. */
  39 static struct gengetopt_args_info conf;
  40 /** Non-NULL if we log to a file. */
  41 static FILE *logfile;
  42 /** The read end of the signal pipe */
  43 static int signal_pipe;
  44 /** Process id of current pre-create-hook/rsync/post-create-hook process. */
  45 static pid_t create_pid;
  46 /** Whether the pre-create-hook/rsync/post-create-hook is currently stopped. */
  47 static int create_process_stopped;
  48 /** Process id of current pre-remove/rm/post-remove process. */
  49 static pid_t remove_pid;
  50 /** When the next snapshot is due. */
  51 static int64_t next_snapshot_time;
  52 /** When to try to remove something. */
  53 static struct timeval next_removal_check;
  54 /** Creation time of the snapshot currently being created. */
  55 static int64_t current_snapshot_creation_time;
  56 /** The snapshot currently being removed. */
  57 struct snapshot *snapshot_currently_being_removed;
  58 /** Needed by the post-create hook. */
  59 static char *path_to_last_complete_snapshot;
  60 static char *name_of_reference_snapshot;
  61 /** \sa \ref snap.h for details. */
  62 enum hook_status snapshot_creation_status;
  63 /** \sa \ref snap.h for details. */
  64 enum hook_status snapshot_removal_status;
  65
  66
  67 DEFINE_DSS_ERRLIST;
  68 static const char const *hook_status_description[] = {HOOK_STATUS_ARRAY};
  69
  70 /* may be called with ds == NULL. */
  71 static int disk_space_low(struct disk_space *ds)
  72 {
  73         struct disk_space ds_struct;
  74
  75         if (!ds) {
  76                 int ret = get_disk_space(".", &ds_struct);
  77                 if (ret < 0)
  78                         return ret;
  79                 ds = &ds_struct;
  80         }
  81         if (conf.min_free_mb_arg)
  82                 if (ds->free_mb < conf.min_free_mb_arg)
  83                         return 1;
  84         if (conf.min_free_percent_arg)
  85                 if (ds->percent_free < conf.min_free_percent_arg)
  86                         return 1;
  87         if (conf.min_free_percent_inodes_arg)
  88                 if (ds->percent_free_inodes < conf.min_free_percent_inodes_arg)
  89                         return 1;
  90         return 0;
  91 }
  92
  93 static void dump_dss_config(const char *msg)
  94 {
  95         const char dash[] = "-----------------------------";
  96         int ret;
  97         FILE *log = logfile? logfile : stderr;
  98         struct disk_space ds;
  99         int64_t now = get_current_time();
 100
 101         if (conf.loglevel_arg > INFO)
 102                 return;
 103
 104         fprintf(log, "%s <%s config> %s\n", dash, msg, dash);
 105         fprintf(log, "\n*** disk space ***\n\n");
 106         ret = get_disk_space(".", &ds);
 107         if (ret >= 0) {
 108                 DSS_INFO_LOG("disk space low: %s\n", disk_space_low(&ds)?
 109                         "yes" : "no");
 110                 log_disk_space(&ds);
 111         } else
 112                 DSS_ERROR_LOG("can not get free disk space: %s\n",
 113                         dss_strerror(-ret));
 114
 115         /* we continue on errors from get_disk_space */
 116
 117         fprintf(log, "\n*** command line and config file options ***\n\n");
 118         cmdline_parser_dump(log, &conf);
 119         fprintf(log, "\n*** internal state ***\n\n");
 120         fprintf(log,
 121                 "pid: %d\n"
 122                 "logile: %s\n"
 123                 "snapshot_currently_being_removed: %s\n"
 124                 "path_to_last_complete_snapshot: %s\n"
 125                 "reference_snapshot: %s\n"
 126                 "snapshot_creation_status: %s\n"
 127                 "snapshot_removal_status: %s\n"
 128                 ,
 129                 (int) getpid(),
 130                 logfile? conf.logfile_arg : "stderr",
 131                 snapshot_currently_being_removed?
 132                         snapshot_currently_being_removed->name : "(none)",
 133                 path_to_last_complete_snapshot?
 134                         path_to_last_complete_snapshot : "(none)",
 135                 name_of_reference_snapshot?
 136                         name_of_reference_snapshot : "(none)",
 137                 hook_status_description[snapshot_creation_status],
 138                 hook_status_description[snapshot_removal_status]
 139         );
 140         if (create_pid != 0)
 141                 fprintf(log,
 142                         "create_pid: %" PRId32 "\n"
 143                         "create process is %sstopped\n"
 144                         ,
 145                         create_pid,
 146                         create_process_stopped? "" : "not "
 147                 );
 148         if (remove_pid != 0)
 149                 fprintf(log, "remove_pid: %" PRId32 "\n", remove_pid);
 150         if (next_snapshot_time != 0)
 151                 fprintf(log, "next snapshot due in %" PRId64 " seconds\n",
 152                         next_snapshot_time - now);
 153         if (current_snapshot_creation_time != 0)
 154                 fprintf(log, "current_snapshot_creation_time: %"
 155                         PRId64 " (%" PRId64 " seconds ago)\n",
 156                         current_snapshot_creation_time,
 157                         now - current_snapshot_creation_time
 158                 );
 159         if (next_removal_check.tv_sec != 0) {
 160                 fprintf(log, "next removal check: %llu (%llu seconds ago)\n",
 161                         (long long unsigned)next_removal_check.tv_sec,
 162                         now - (long long unsigned)next_removal_check.tv_sec
 163                 );
 164
 165         }
 166         fprintf(log, "%s </%s config> %s\n", dash, msg, dash);
 167 }
 168
 169 /* a litte cpp magic helps to DRY */
 170 #define COMMANDS \
 171         COMMAND(ls) \
 172         COMMAND(create) \
 173         COMMAND(prune) \
 174         COMMAND(run) \
 175         COMMAND(kill)
 176 #define COMMAND(x) static int com_ ##x(void);
 177 COMMANDS
 178 #undef COMMAND
 179 #define COMMAND(x) if (conf.x ##_given) return com_ ##x();
 180 static int call_command_handler(void)
 181 {
 182         COMMANDS
 183         DSS_EMERG_LOG("BUG: did not find command handler\n");
 184         return -E_BUG;
 185 }
 186 #undef COMMAND
 187 #undef COMMANDS
 188
 189 /**
 190  * The log function of dss.
 191  *
 192  * \param ll Loglevel.
 193  * \param fml Usual format string.
 194  *
 195  * All DSS_XXX_LOG() macros use this function.
 196  */
 197 __printf_2_3 void dss_log(int ll, const char* fmt,...)
 198 {
 199         va_list argp;
 200         FILE *outfd;
 201         struct tm *tm;
 202         time_t t1;
 203         char str[255] = "";
 204
 205         if (ll < conf.loglevel_arg)
 206                 return;
 207         outfd = logfile? logfile : stderr;
 208         time(&t1);
 209         tm = localtime(&t1);
 210         strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
 211         fprintf(outfd, "%s ", str);
 212         if (conf.loglevel_arg <= INFO)
 213                 fprintf(outfd, "%i: ", ll);
 214         va_start(argp, fmt);
 215         vfprintf(outfd, fmt, argp);
 216         va_end(argp);
 217 }
 218
 219 /**
 220  * Print a message either to stdout or to the log file.
 221  */
 222 static __printf_1_2 void dss_msg(const char* fmt,...)
 223 {
 224         FILE *outfd = conf.daemon_given? logfile : stdout;
 225         va_list argp;
 226         va_start(argp, fmt);
 227         vfprintf(outfd, fmt, argp);
 228         va_end(argp);
 229 }
 230
 231 static char *get_config_file_name(void)
 232 {
 233         char *home, *config_file;
 234
 235         if (conf.config_file_given)
 236                 return dss_strdup(conf.config_file_arg);
 237         home = get_homedir();
 238         config_file = make_message("%s/.dssrc", home);
 239         free(home);
 240         return config_file;
 241 }
 242
 243 static int com_kill(void)
 244 {
 245         pid_t pid;
 246         char *config_file = get_config_file_name();
 247         int ret = get_dss_pid(config_file, &pid);
 248
 249         free(config_file);
 250         if (ret < 0)
 251                 return ret;
 252         if (conf.dry_run_given) {
 253                 dss_msg("%d\n", (int)pid);
 254                 return 0;
 255         }
 256         ret = kill(pid, SIGTERM);
 257         if (ret < 0)
 258                 return -ERRNO_TO_DSS_ERROR(errno);
 259         return 1;
 260 }
 261
 262 static void dss_get_snapshot_list(struct snapshot_list *sl)
 263 {
 264         get_snapshot_list(sl, conf.unit_interval_arg, conf.num_intervals_arg);
 265 }
 266
 267 static int64_t compute_next_snapshot_time(void)
 268 {
 269         int64_t x = 0, now = get_current_time(), unit_interval
 270                 = 24 * 3600 * conf.unit_interval_arg, ret;
 271         unsigned wanted = desired_number_of_snapshots(0, conf.num_intervals_arg),
 272                 num_complete_snapshots = 0;
 273         int i;
 274         struct snapshot *s = NULL;
 275         struct snapshot_list sl;
 276
 277         dss_get_snapshot_list(&sl);
 278         FOR_EACH_SNAPSHOT(s, i, &sl) {
 279                 if (!(s->flags & SS_COMPLETE))
 280                         continue;
 281                 num_complete_snapshots++;
 282                 x += s->completion_time - s->creation_time;
 283         }
 284         assert(x >= 0);
 285
 286         ret = now;
 287         if (num_complete_snapshots == 0)
 288                 goto out;
 289         x /= num_complete_snapshots; /* avg time to create one snapshot */
 290         if (unit_interval < x * wanted) /* oops, no sleep at all */
 291                 goto out;
 292         ret = s->completion_time + unit_interval / wanted - x;
 293 out:
 294         free_snapshot_list(&sl);
 295         return ret;
 296 }
 297
 298 static inline void invalidate_next_snapshot_time(void)
 299 {
 300         next_snapshot_time = 0;
 301 }
 302
 303 static inline int next_snapshot_time_is_valid(void)
 304 {
 305         return next_snapshot_time != 0;
 306 }
 307
 308 static int next_snapshot_is_due(void)
 309 {
 310         int64_t now = get_current_time();
 311
 312         if (!next_snapshot_time_is_valid())
 313                 next_snapshot_time = compute_next_snapshot_time();
 314         if (next_snapshot_time <= now) {
 315                 DSS_DEBUG_LOG("next snapshot: now\n");
 316                 return 1;
 317         }
 318         DSS_DEBUG_LOG("next snapshot due in %" PRId64 " seconds\n",
 319                 next_snapshot_time - now);
 320         return 0;
 321 }
 322
 323 static int pre_create_hook(void)
 324 {
 325         int ret, fds[3] = {0, 0, 0};
 326
 327         assert(snapshot_creation_status == HS_READY);
 328         /* make sure that the next snapshot time will be recomputed */
 329         invalidate_next_snapshot_time();
 330         DSS_DEBUG_LOG("executing %s\n", conf.pre_create_hook_arg);
 331         ret = dss_exec_cmdline_pid(&create_pid,
 332                 conf.pre_create_hook_arg, fds);
 333         if (ret < 0)
 334                 return ret;
 335         snapshot_creation_status = HS_PRE_RUNNING;
 336         return ret;
 337 }
 338
 339 static int pre_remove_hook(struct snapshot *s, const char *why)
 340 {
 341         int ret, fds[3] = {0, 0, 0};
 342         char *cmd;
 343
 344         if (!s)
 345                 return 0;
 346         DSS_DEBUG_LOG("%s snapshot %s\n", why, s->name);
 347         assert(snapshot_removal_status == HS_READY);
 348         assert(remove_pid == 0);
 349         assert(!snapshot_currently_being_removed);
 350
 351         snapshot_currently_being_removed = dss_malloc(sizeof(struct snapshot));
 352         *snapshot_currently_being_removed = *s;
 353         snapshot_currently_being_removed->name = dss_strdup(s->name);
 354
 355         cmd = make_message("%s %s/%s", conf.pre_remove_hook_arg,
 356                 conf.dest_dir_arg, s->name);
 357         DSS_DEBUG_LOG("executing %s\n", cmd);
 358         ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
 359         free(cmd);
 360         if (ret < 0)
 361                 return ret;
 362         snapshot_removal_status = HS_PRE_RUNNING;
 363         return ret;
 364 }
 365
 366 static int exec_rm(void)
 367 {
 368         struct snapshot *s = snapshot_currently_being_removed;
 369         int fds[3] = {0, 0, 0};
 370         char *new_name = being_deleted_name(s);
 371         char *argv[] = {"rm", "-rf", new_name, NULL};
 372         int ret;
 373
 374         assert(snapshot_removal_status == HS_PRE_SUCCESS);
 375         assert(remove_pid == 0);
 376
 377         DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
 378         ret = dss_rename(s->name, new_name);
 379         if (ret < 0)
 380                 goto out;
 381         ret = dss_exec(&remove_pid, argv[0], argv, fds);
 382         if (ret < 0)
 383                 goto out;
 384         snapshot_removal_status = HS_RUNNING;
 385 out:
 386         free(new_name);
 387         return ret;
 388 }
 389
 390 static int snapshot_is_being_created(struct snapshot *s)
 391 {
 392         return s->creation_time == current_snapshot_creation_time;
 393 }
 394
 395 static struct snapshot *find_orphaned_snapshot(struct snapshot_list *sl)
 396 {
 397         struct snapshot *s;
 398         int i;
 399
 400         DSS_DEBUG_LOG("looking for orphaned snapshots\n");
 401         FOR_EACH_SNAPSHOT(s, i, sl) {
 402                 if (snapshot_is_being_created(s))
 403                         continue;
 404                 /*
 405                  * We know that no rm is currently running, so if s is marked
 406                  * as being deleted, a previously started rm must have failed.
 407                  */
 408                 if (s->flags & SS_BEING_DELETED)
 409                         return s;
 410
 411                 if (s->flags & SS_COMPLETE) /* good snapshot */
 412                         continue;
 413                 /*
 414                  * This snapshot is incomplete and it is not the snapshot
 415                  * currently being created. However, we must not remove it if
 416                  * rsync is about to be restarted. As only the newest snapshot
 417                  * can be restarted, this snapshot is orphaned if it is not the
 418                  * newest snapshot or if we are not about to restart rsync.
 419                  */
 420                 if (get_newest_snapshot(sl) != s)
 421                         return s;
 422                 if (snapshot_creation_status != HS_NEEDS_RESTART)
 423                         return s;
 424         }
 425         /* no orphaned snapshots */
 426         return NULL;
 427 }
 428
 429 static int is_reference_snapshot(struct snapshot *s)
 430 {
 431         if (!name_of_reference_snapshot)
 432                 return 0;
 433         return strcmp(s->name, name_of_reference_snapshot)? 0 : 1;
 434 }
 435
 436 /*
 437  * return: 0: no redundant snapshots, 1: rm process started, negative: error
 438  */
 439 static struct snapshot *find_redundant_snapshot(struct snapshot_list *sl)
 440 {
 441         int i, interval;
 442         struct snapshot *s;
 443         unsigned missing = 0;
 444
 445         DSS_DEBUG_LOG("looking for intervals containing too many snapshots\n");
 446         for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
 447                 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
 448                 unsigned num = sl->interval_count[interval];
 449                 struct snapshot *victim = NULL, *prev = NULL;
 450                 int64_t score = LONG_MAX;
 451
 452                 if (keep >= num)
 453                         missing += keep - num;
 454 //              DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
 455 //                      interval, keep, num, missing);
 456                 if (keep + missing >= num)
 457                         continue;
 458                 /* redundant snapshot in this interval, pick snapshot with lowest score */
 459                 FOR_EACH_SNAPSHOT(s, i, sl) {
 460                         int64_t this_score;
 461
 462                         if (snapshot_is_being_created(s))
 463                                 continue;
 464                         if (is_reference_snapshot(s))
 465                                 continue;
 466                         //DSS_DEBUG_LOG("checking %s\n", s->name);
 467                         if (s->interval > interval) {
 468                                 prev = s;
 469                                 continue;
 470                         }
 471                         if (s->interval < interval)
 472                                 break;
 473                         if (!victim) {
 474                                 victim = s;
 475                                 prev = s;
 476                                 continue;
 477                         }
 478                         assert(prev);
 479                         /* check if s is a better victim */
 480                         this_score = s->creation_time - prev->creation_time;
 481                         assert(this_score >= 0);
 482                         //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
 483                         if (this_score < score) {
 484                                 score = this_score;
 485                                 victim = s;
 486                         }
 487                         prev = s;
 488                 }
 489                 assert(victim);
 490                 return victim;
 491         }
 492         return NULL;
 493 }
 494
 495 static struct snapshot *find_outdated_snapshot(struct snapshot_list *sl)
 496 {
 497         int i;
 498         struct snapshot *s;
 499
 500         DSS_DEBUG_LOG("looking for snapshots belonging to intervals >= %d\n",
 501                 conf.num_intervals_arg);
 502         FOR_EACH_SNAPSHOT(s, i, sl) {
 503                 if (snapshot_is_being_created(s))
 504                         continue;
 505                 if (is_reference_snapshot(s))
 506                         continue;
 507                 if (s->interval < conf.num_intervals_arg)
 508                         continue;
 509                 return s;
 510         }
 511         return NULL;
 512 }
 513
 514 struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
 515 {
 516         int i;
 517         struct snapshot *s;
 518         FOR_EACH_SNAPSHOT(s, i, sl) {
 519                 if (snapshot_is_being_created(s))
 520                         continue;
 521                 if (is_reference_snapshot(s))
 522                         continue;
 523                 DSS_INFO_LOG("oldest removable snapshot: %s\n", s->name);
 524                 return s;
 525         }
 526         return NULL;
 527 }
 528
 529 static int rename_incomplete_snapshot(int64_t start)
 530 {
 531         char *old_name;
 532         int ret;
 533
 534         free(path_to_last_complete_snapshot);
 535         ret = complete_name(start, get_current_time(),
 536                 &path_to_last_complete_snapshot);
 537         if (ret < 0)
 538                 return ret;
 539         old_name = incomplete_name(start);
 540         ret = dss_rename(old_name, path_to_last_complete_snapshot);
 541         if (ret >= 0)
 542                 DSS_NOTICE_LOG("%s -> %s\n", old_name,
 543                         path_to_last_complete_snapshot);
 544         free(old_name);
 545         return ret;
 546 }
 547
 548 static int try_to_free_disk_space(void)
 549 {
 550         int ret;
 551         struct snapshot_list sl;
 552         struct snapshot *victim;
 553         struct timeval now;
 554         const char *why;
 555         int low_disk_space;
 556
 557         ret = disk_space_low(NULL);
 558         if (ret < 0)
 559                 return ret;
 560         low_disk_space = ret;
 561         gettimeofday(&now, NULL);
 562         if (tv_diff(&next_removal_check, &now, NULL) > 0)
 563                 return 0;
 564         if (!low_disk_space) {
 565                 if (conf.keep_redundant_given)
 566                         return 0;
 567                 if (snapshot_creation_status != HS_READY)
 568                         return 0;
 569                 if (next_snapshot_is_due())
 570                         return 0;
 571         }
 572         dss_get_snapshot_list(&sl);
 573         ret = 0;
 574         if (!low_disk_space && sl.num_snapshots <= 1)
 575                 goto out;
 576         why = "outdated";
 577         victim = find_outdated_snapshot(&sl);
 578         if (victim)
 579                 goto remove;
 580         why = "redundant";
 581         victim = find_redundant_snapshot(&sl);
 582         if (victim)
 583                 goto remove;
 584         /* try harder only if disk space is low */
 585         if (!low_disk_space)
 586                 goto out;
 587         why = "orphaned";
 588         victim = find_orphaned_snapshot(&sl);
 589         if (victim)
 590                 goto remove;
 591         DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
 592         victim = find_oldest_removable_snapshot(&sl);
 593         if (victim)
 594                 goto remove;
 595         DSS_CRIT_LOG("uhuhu: disk space low and nothing to remove\n");
 596         ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
 597         goto out;
 598 remove:
 599         ret = pre_remove_hook(victim, why);
 600 out:
 601         free_snapshot_list(&sl);
 602         return ret;
 603 }
 604
 605 static int post_create_hook(void)
 606 {
 607         int ret, fds[3] = {0, 0, 0};
 608         char *cmd;
 609
 610         cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
 611                 conf.dest_dir_arg, path_to_last_complete_snapshot);
 612         DSS_NOTICE_LOG("executing %s\n", cmd);
 613         ret = dss_exec_cmdline_pid(&create_pid, cmd, fds);
 614         free(cmd);
 615         if (ret < 0)
 616                 return ret;
 617         snapshot_creation_status = HS_POST_RUNNING;
 618         return ret;
 619 }
 620
 621 static int post_remove_hook(void)
 622 {
 623         int ret, fds[3] = {0, 0, 0};
 624         char *cmd;
 625         struct snapshot *s = snapshot_currently_being_removed;
 626
 627         assert(s);
 628
 629         cmd = make_message("%s %s/%s", conf.post_remove_hook_arg,
 630                 conf.dest_dir_arg, s->name);
 631         DSS_NOTICE_LOG("executing %s\n", cmd);
 632         ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
 633         free(cmd);
 634         if (ret < 0)
 635                 return ret;
 636         snapshot_removal_status = HS_POST_RUNNING;
 637         return ret;
 638 }
 639
 640 static void dss_kill(pid_t pid, int sig, const char *msg)
 641 {
 642         const char *signame, *process_name;
 643
 644         if (pid == 0)
 645                 return;
 646         switch (sig) {
 647         case SIGTERM: signame = "TERM"; break;
 648         case SIGSTOP: signame = "STOP"; break;
 649         case SIGCONT: signame = "CONT"; break;
 650         default: signame = "????";
 651         }
 652
 653         if (pid == create_pid)
 654                 process_name = "create";
 655         else if (pid == remove_pid)
 656                 process_name = "remove";
 657         else process_name = "??????";
 658
 659         if (msg)
 660                 DSS_INFO_LOG("%s\n", msg);
 661         DSS_DEBUG_LOG("sending signal %d (%s) to pid %d (%s process)\n",
 662                 sig, signame, (int)pid, process_name);
 663         if (kill(pid, sig) >= 0)
 664                 return;
 665         DSS_INFO_LOG("failed to send signal %d (%s) to pid %d (%s process)\n",
 666                 sig, signame, (int)pid, process_name);
 667 }
 668
 669 static void stop_create_process(void)
 670 {
 671         if (create_process_stopped)
 672                 return;
 673         dss_kill(create_pid, SIGSTOP, "suspending create process");
 674         create_process_stopped = 1;
 675 }
 676
 677 static void restart_create_process(void)
 678 {
 679         if (!create_process_stopped)
 680                 return;
 681         dss_kill(create_pid, SIGCONT, "resuming create process");
 682         create_process_stopped = 0;
 683 }
 684
 685 /**
 686  * Print a log message about the exit status of a child.
 687  */
 688 static void log_termination_msg(pid_t pid, int status)
 689 {
 690         if (WIFEXITED(status))
 691                 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
 692                         WEXITSTATUS(status));
 693         else if (WIFSIGNALED(status))
 694                 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
 695                         WTERMSIG(status));
 696         else
 697                 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
 698 }
 699
 700 static int wait_for_process(pid_t pid, int *status)
 701 {
 702         int ret;
 703
 704         DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
 705         for (;;) {
 706                 fd_set rfds;
 707
 708                 FD_ZERO(&rfds);
 709                 FD_SET(signal_pipe, &rfds);
 710                 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
 711                 if (ret < 0)
 712                         break;
 713                 ret = next_signal();
 714                 if (!ret)
 715                         continue;
 716                 if (ret == SIGCHLD) {
 717                         ret = waitpid(pid, status, 0);
 718                         if (ret >= 0)
 719                                 break;
 720                         if (errno != EINTR) { /* error */
 721                                 ret = -ERRNO_TO_DSS_ERROR(errno);
 722                                 break;
 723                         }
 724                 }
 725                 /* SIGINT or SIGTERM */
 726                 dss_kill(pid, SIGTERM, "killing child process");
 727         }
 728         if (ret < 0)
 729                 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
 730         else
 731                 log_termination_msg(pid, *status);
 732         return ret;
 733 }
 734
 735 static void handle_pre_remove_exit(int status)
 736 {
 737         if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 738                 snapshot_removal_status = HS_READY;
 739                 gettimeofday(&next_removal_check, NULL);
 740                 next_removal_check.tv_sec += 60;
 741                 return;
 742         }
 743         snapshot_removal_status = HS_PRE_SUCCESS;
 744 }
 745
 746 static int handle_rm_exit(int status)
 747 {
 748         if (!WIFEXITED(status)) {
 749                 snapshot_removal_status = HS_READY;
 750                 return -E_INVOLUNTARY_EXIT;
 751         }
 752         if (WEXITSTATUS(status)) {
 753                 snapshot_removal_status = HS_READY;
 754                 return -E_BAD_EXIT_CODE;
 755         }
 756         snapshot_removal_status = HS_SUCCESS;
 757         return 1;
 758 }
 759
 760 static void handle_post_remove_exit(void)
 761 {
 762         snapshot_removal_status = HS_READY;
 763 }
 764
 765 static int handle_remove_exit(int status)
 766 {
 767         int ret;
 768         struct snapshot *s = snapshot_currently_being_removed;
 769
 770         assert(s);
 771         switch (snapshot_removal_status) {
 772         case HS_PRE_RUNNING:
 773                 handle_pre_remove_exit(status);
 774                 ret = 1;
 775                 break;
 776         case HS_RUNNING:
 777                 ret = handle_rm_exit(status);
 778                 break;
 779         case HS_POST_RUNNING:
 780                 handle_post_remove_exit();
 781                 ret = 1;
 782                 break;
 783         default:
 784                 ret = -E_BUG;
 785         }
 786         if (snapshot_removal_status == HS_READY) {
 787                 free(s->name);
 788                 free(s);
 789                 snapshot_currently_being_removed = NULL;
 790         }
 791         remove_pid = 0;
 792         return ret;
 793 }
 794
 795 static int wait_for_remove_process(void)
 796 {
 797         int status, ret;
 798
 799         assert(remove_pid);
 800         assert(
 801                 snapshot_removal_status == HS_PRE_RUNNING ||
 802                 snapshot_removal_status == HS_RUNNING ||
 803                 snapshot_removal_status == HS_POST_RUNNING
 804         );
 805         ret = wait_for_process(remove_pid, &status);
 806         if (ret < 0)
 807                 return ret;
 808         return handle_remove_exit(status);
 809 }
 810
 811 static int handle_rsync_exit(int status)
 812 {
 813         int es, ret;
 814
 815         if (!WIFEXITED(status)) {
 816                 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)create_pid);
 817                 ret = -E_INVOLUNTARY_EXIT;
 818                 snapshot_creation_status = HS_READY;
 819                 goto out;
 820         }
 821         es = WEXITSTATUS(status);
 822         /*
 823          * Restart rsync on non-fatal errors:
 824          * 12: Error in rsync protocol data stream
 825          * 13: Errors with program diagnostics
 826          */
 827         if (es == 12 || es == 13) {
 828                 DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
 829                         (int)create_pid, es);
 830                 snapshot_creation_status = HS_NEEDS_RESTART;
 831                 next_snapshot_time = get_current_time() + 60;
 832                 ret = 1;
 833                 goto out;
 834         }
 835         if (es != 0 && es != 23 && es != 24) {
 836                 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)create_pid, es);
 837                 ret = -E_BAD_EXIT_CODE;
 838                 snapshot_creation_status = HS_READY;
 839                 goto out;
 840         }
 841         ret = rename_incomplete_snapshot(current_snapshot_creation_time);
 842         if (ret < 0)
 843                 goto out;
 844         snapshot_creation_status = HS_SUCCESS;
 845         free(name_of_reference_snapshot);
 846         name_of_reference_snapshot = NULL;
 847 out:
 848         create_process_stopped = 0;
 849         return ret;
 850 }
 851
 852 static int handle_pre_create_hook_exit(int status)
 853 {
 854         int es, ret;
 855         static int warn_count;
 856
 857         if (!WIFEXITED(status)) {
 858                 snapshot_creation_status = HS_READY;
 859                 ret = -E_INVOLUNTARY_EXIT;
 860                 goto out;
 861         }
 862         es = WEXITSTATUS(status);
 863         if (es) {
 864                 if (!warn_count--) {
 865                         DSS_NOTICE_LOG("pre_create_hook %s returned %d\n",
 866                                 conf.pre_create_hook_arg, es);
 867                         DSS_NOTICE_LOG("deferring snapshot creation...\n");
 868                         warn_count = 60; /* warn only once per hour */
 869                 }
 870                 next_snapshot_time = get_current_time() + 60;
 871                 snapshot_creation_status = HS_READY;
 872                 ret = 0;
 873                 goto out;
 874         }
 875         warn_count = 0;
 876         snapshot_creation_status = HS_PRE_SUCCESS;
 877         ret = 1;
 878 out:
 879         return ret;
 880 }
 881
 882 static int handle_sigchld(void)
 883 {
 884         pid_t pid;
 885         int status, ret = reap_child(&pid, &status);
 886
 887         if (ret <= 0)
 888                 return ret;
 889
 890         if (pid == create_pid) {
 891                 switch (snapshot_creation_status) {
 892                 case HS_PRE_RUNNING:
 893                         ret = handle_pre_create_hook_exit(status);
 894                         break;
 895                 case HS_RUNNING:
 896                         ret = handle_rsync_exit(status);
 897                         break;
 898                 case HS_POST_RUNNING:
 899                         snapshot_creation_status = HS_READY;
 900                         ret = 1;
 901                         break;
 902                 default:
 903                         DSS_EMERG_LOG("BUG: create can't die in status %d\n",
 904                                 snapshot_creation_status);
 905                         return -E_BUG;
 906                 }
 907                 create_pid = 0;
 908                 return ret;
 909         }
 910         if (pid == remove_pid) {
 911                 ret = handle_remove_exit(status);
 912                 if (ret < 0)
 913                         return ret;
 914                 return ret;
 915         }
 916         DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
 917         return -E_BUG;
 918 }
 919
 920 static int check_config(void)
 921 {
 922         if (conf.unit_interval_arg <= 0) {
 923                 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
 924                 return -E_INVALID_NUMBER;
 925         }
 926         DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
 927         if (conf.num_intervals_arg <= 0) {
 928                 DSS_ERROR_LOG("bad number of intervals  %i\n", conf.num_intervals_arg);
 929                 return -E_INVALID_NUMBER;
 930         }
 931         DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
 932         return 1;
 933 }
 934
 935 /*
 936  * Returns < 0 on errors, 0 if no config file is given and > 0 if the config
 937  * file was read successfully.
 938  */
 939 static int parse_config_file(int override)
 940 {
 941         int ret, config_file_exists;
 942         char *config_file = get_config_file_name();
 943         struct stat statbuf;
 944         char *old_logfile_arg = NULL;
 945         int old_daemon_given = 0;
 946
 947         if (override) { /* SIGHUP */
 948                 if (conf.logfile_given)
 949                         old_logfile_arg = dss_strdup(conf.logfile_arg);
 950                 old_daemon_given = conf.daemon_given;
 951         }
 952
 953         config_file_exists = !stat(config_file, &statbuf);
 954         if (!config_file_exists && conf.config_file_given) {
 955                 ret = -ERRNO_TO_DSS_ERROR(errno);
 956                 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
 957                 goto out;
 958         }
 959         if (config_file_exists) {
 960                 struct cmdline_parser_params params = {
 961                         .override = override,
 962                         .initialize = 0,
 963                         .check_required = 1,
 964                         .check_ambiguity = 0,
 965                         .print_errors = 1
 966                 };
 967                 if (override) { /* invalidate all rsync options */
 968                         int i;
 969
 970                         for (i = 0; i < conf.rsync_option_given; i++) {
 971                                 free(conf.rsync_option_arg[i]);
 972                                 conf.rsync_option_arg[i] = NULL;
 973                         }
 974                         conf.rsync_option_given = 0;
 975                 }
 976                 cmdline_parser_config_file(config_file, &conf, &params);
 977         }
 978         ret = check_config();
 979         if (ret < 0)
 980                 goto out;
 981         if (override) {
 982                 /* don't change daemon mode on SIGHUP */
 983                 conf.daemon_given = old_daemon_given;
 984                 close_log(logfile);
 985                 logfile = NULL;
 986                 if (conf.logfile_given)
 987                         free(old_logfile_arg);
 988                 else if (conf.daemon_given) { /* re-use old logfile */
 989                         conf.logfile_arg = old_logfile_arg;
 990                         conf.logfile_given = 1;
 991                 }
 992         }
 993         if (conf.logfile_given && conf.run_given && conf.daemon_given) {
 994                 logfile = open_log(conf.logfile_arg);
 995                 log_welcome(conf.loglevel_arg);
 996         }
 997         DSS_DEBUG_LOG("loglevel: %d\n", conf.loglevel_arg);
 998         ret = config_file_exists;
 999 out:
1000         free(config_file);
1001         if (ret < 0)
1002                 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1003         return ret;
1004 }
1005
1006 static int change_to_dest_dir(void)
1007 {
1008         DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
1009         return dss_chdir(conf.dest_dir_arg);
1010 }
1011
1012 static int handle_sighup(void)
1013 {
1014         int ret;
1015
1016         DSS_NOTICE_LOG("SIGHUP, re-reading config\n");
1017         dump_dss_config("old");
1018         ret = parse_config_file(1);
1019         if (ret < 0)
1020                 return ret;
1021         dump_dss_config("reloaded");
1022         invalidate_next_snapshot_time();
1023         return change_to_dest_dir();
1024 }
1025
1026 static int handle_signal(void)
1027 {
1028         int sig, ret = next_signal();
1029
1030         if (ret <= 0)
1031                 goto out;
1032         sig = ret;
1033         switch (sig) {
1034         case SIGINT:
1035         case SIGTERM:
1036                 restart_create_process();
1037                 dss_kill(create_pid, SIGTERM, NULL);
1038                 dss_kill(remove_pid, SIGTERM, NULL);
1039                 ret = -E_SIGNAL;
1040                 break;
1041         case SIGHUP:
1042                 ret = handle_sighup();
1043                 break;
1044         case SIGCHLD:
1045                 ret = handle_sigchld();
1046                 break;
1047         }
1048 out:
1049         if (ret < 0)
1050                 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
1051         return ret;
1052 }
1053
1054 /*
1055  * We can not use rsync locally if the local user is different from the remote
1056  * user or if the src dir is not on the local host (or both).
1057  */
1058 static int use_rsync_locally(char *logname)
1059 {
1060         char *h = conf.remote_host_arg;
1061
1062         if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
1063                 return 0;
1064         if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
1065                 return 0;
1066         return 1;
1067 }
1068
1069 static int rename_resume_snap(int64_t creation_time)
1070 {
1071         struct snapshot_list sl = {.num_snapshots = 0};
1072         struct snapshot *s = NULL;
1073         char *new_name = incomplete_name(creation_time);
1074         int ret;
1075         const char *why;
1076
1077         ret = 0;
1078         if (conf.no_resume_given)
1079                 goto out;
1080         dss_get_snapshot_list(&sl);
1081         /*
1082          * Snapshot recycling: We first look at the newest snapshot. If this
1083          * snapshot happens to be incomplete, the last rsync process was
1084          * aborted and we reuse this one. Otherwise we look at snapshots which
1085          * could be removed (outdated and redundant snapshots) as candidates
1086          * for recycling. If no outdated/redundant snapshot exists, we check if
1087          * there is an orphaned snapshot, which likely is useless anyway.
1088          *
1089          * Only if no existing snapshot is suitable for recycling, we bite the
1090          * bullet and create a new one.
1091          */
1092         s = get_newest_snapshot(&sl);
1093         if (!s) /* no snapshots at all */
1094                 goto out;
1095         /* re-use last snapshot if it is incomplete */
1096         why = "aborted";
1097         if ((s->flags & SS_COMPLETE) == 0)
1098                 goto out;
1099         why = "outdated";
1100         s = find_outdated_snapshot(&sl);
1101         if (s)
1102                 goto out;
1103         why = "redundant";
1104         s = find_redundant_snapshot(&sl);
1105         if (s)
1106                 goto out;
1107         why = "orphaned";
1108         s = find_orphaned_snapshot(&sl);
1109 out:
1110         if (s) {
1111                 DSS_INFO_LOG("reusing %s snapshot %s\n", why, s->name);
1112                 ret = dss_rename(s->name, new_name);
1113         }
1114         if (ret >= 0)
1115                 DSS_NOTICE_LOG("creating new snapshot %s\n", new_name);
1116         free(new_name);
1117         free_snapshot_list(&sl);
1118         return ret;
1119 }
1120
1121 static void create_rsync_argv(char ***argv, int64_t *num)
1122 {
1123         char *logname;
1124         int i = 0, j;
1125         struct snapshot_list sl;
1126
1127         dss_get_snapshot_list(&sl);
1128         assert(!name_of_reference_snapshot);
1129         name_of_reference_snapshot = name_of_newest_complete_snapshot(&sl);
1130         free_snapshot_list(&sl);
1131
1132         *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
1133         (*argv)[i++] = dss_strdup("rsync");
1134         (*argv)[i++] = dss_strdup("-aq");
1135         (*argv)[i++] = dss_strdup("--delete");
1136         for (j = 0; j < conf.rsync_option_given; j++)
1137                 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
1138         if (name_of_reference_snapshot) {
1139                 DSS_INFO_LOG("using %s as reference\n", name_of_reference_snapshot);
1140                 (*argv)[i++] = make_message("--link-dest=../%s",
1141                         name_of_reference_snapshot);
1142         } else
1143                 DSS_INFO_LOG("no suitable reference snapshot found\n");
1144         logname = dss_logname();
1145         if (use_rsync_locally(logname))
1146                 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
1147         else
1148                 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
1149                         conf.remote_user_arg : logname,
1150                         conf.remote_host_arg, conf.source_dir_arg);
1151         free(logname);
1152         *num = get_current_time();
1153         (*argv)[i++] = incomplete_name(*num);
1154         (*argv)[i++] = NULL;
1155         for (j = 0; j < i; j++)
1156                 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
1157 }
1158
1159 static void free_rsync_argv(char **argv)
1160 {
1161         int i;
1162
1163         if (!argv)
1164                 return;
1165         for (i = 0; argv[i]; i++)
1166                 free(argv[i]);
1167         free(argv);
1168 }
1169
1170 static int create_snapshot(char **argv)
1171 {
1172         int ret, fds[3] = {0, 0, 0};
1173
1174         ret = rename_resume_snap(current_snapshot_creation_time);
1175         if (ret < 0)
1176                 return ret;
1177         ret = dss_exec(&create_pid, argv[0], argv, fds);
1178         if (ret < 0)
1179                 return ret;
1180         snapshot_creation_status = HS_RUNNING;
1181         return ret;
1182 }
1183
1184 static int select_loop(void)
1185 {
1186         int ret;
1187         /* check every 60 seconds for free disk space */
1188         struct timeval tv;
1189         char **rsync_argv = NULL;
1190
1191         for (;;) {
1192                 fd_set rfds;
1193                 struct timeval *tvp;
1194
1195                 if (remove_pid)
1196                         tvp = NULL; /* sleep until rm hook/process dies */
1197                 else { /* sleep one minute */
1198                         tv.tv_sec = 60;
1199                         tv.tv_usec = 0;
1200                         tvp = &tv;
1201                 }
1202                 FD_ZERO(&rfds);
1203                 FD_SET(signal_pipe, &rfds);
1204                 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
1205                 if (ret < 0)
1206                         goto out;
1207                 if (FD_ISSET(signal_pipe, &rfds)) {
1208                         ret = handle_signal();
1209                         if (ret < 0)
1210                                 goto out;
1211                 }
1212                 if (remove_pid)
1213                         continue;
1214                 if (snapshot_removal_status == HS_PRE_SUCCESS) {
1215                         ret = exec_rm();
1216                         if (ret < 0)
1217                                 goto out;
1218                         continue;
1219                 }
1220                 if (snapshot_removal_status == HS_SUCCESS) {
1221                         ret = post_remove_hook();
1222                         if (ret < 0)
1223                                 goto out;
1224                         continue;
1225                 }
1226                 ret = try_to_free_disk_space();
1227                 if (ret < 0)
1228                         goto out;
1229                 if (snapshot_removal_status != HS_READY) {
1230                         stop_create_process();
1231                         continue;
1232                 }
1233                 restart_create_process();
1234                 switch (snapshot_creation_status) {
1235                 case HS_READY:
1236                         if (!next_snapshot_is_due())
1237                                 continue;
1238                         ret = pre_create_hook();
1239                         if (ret < 0)
1240                                 goto out;
1241                         continue;
1242                 case HS_PRE_RUNNING:
1243                 case HS_RUNNING:
1244                 case HS_POST_RUNNING:
1245                         continue;
1246                 case HS_PRE_SUCCESS:
1247                         if (!name_of_reference_snapshot) {
1248                                 free_rsync_argv(rsync_argv);
1249                                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1250                         }
1251                         ret = create_snapshot(rsync_argv);
1252                         if (ret < 0)
1253                                 goto out;
1254                         continue;
1255                 case HS_NEEDS_RESTART:
1256                         if (!next_snapshot_is_due())
1257                                 continue;
1258                         ret = create_snapshot(rsync_argv);
1259                         if (ret < 0)
1260                                 goto out;
1261                         continue;
1262                 case HS_SUCCESS:
1263                         ret = post_create_hook();
1264                         if (ret < 0)
1265                                 goto out;
1266                         continue;
1267                 }
1268         }
1269 out:
1270         return ret;
1271 }
1272
1273 static void exit_hook(int exit_code)
1274 {
1275         int fds[3] = {0, 0, 0};
1276         char *argv[] = {conf.exit_hook_arg, dss_strerror(-exit_code), NULL};
1277         pid_t pid;
1278
1279         DSS_NOTICE_LOG("executing %s %s\n", argv[0], argv[1]);
1280         dss_exec(&pid, conf.exit_hook_arg, argv, fds);
1281 }
1282
1283 static void lock_dss_or_die(void)
1284 {
1285         char *config_file = get_config_file_name();
1286         int ret = lock_dss(config_file);
1287
1288         free(config_file);
1289         if (ret < 0) {
1290                 DSS_EMERG_LOG("failed to lock: %s\n", dss_strerror(-ret));
1291                 exit(EXIT_FAILURE);
1292         }
1293 }
1294
1295 static int com_run(void)
1296 {
1297         int ret;
1298
1299         lock_dss_or_die();
1300         if (conf.dry_run_given) {
1301                 DSS_ERROR_LOG("dry_run not supported by this command\n");
1302                 return -E_SYNTAX;
1303         }
1304         ret = install_sighandler(SIGHUP);
1305         if (ret < 0)
1306                 return ret;
1307         ret = select_loop();
1308         if (ret >= 0) /* impossible */
1309                 ret = -E_BUG;
1310         exit_hook(ret);
1311         return ret;
1312 }
1313
1314 static int com_prune(void)
1315 {
1316         int ret;
1317         struct snapshot_list sl;
1318         struct snapshot *victim;
1319         struct disk_space ds;
1320         const char *why;
1321
1322         lock_dss_or_die();
1323         ret = get_disk_space(".", &ds);
1324         if (ret < 0)
1325                 return ret;
1326         log_disk_space(&ds);
1327         dss_get_snapshot_list(&sl);
1328         why = "outdated";
1329         victim = find_outdated_snapshot(&sl);
1330         if (victim)
1331                 goto rm;
1332         why = "redundant";
1333         victim = find_redundant_snapshot(&sl);
1334         if (victim)
1335                 goto rm;
1336         ret = 0;
1337         goto out;
1338 rm:
1339         if (conf.dry_run_given) {
1340                 dss_msg("%s snapshot %s (interval = %i)\n",
1341                         why, victim->name, victim->interval);
1342                 ret = 0;
1343                 goto out;
1344         }
1345         ret = pre_remove_hook(victim, why);
1346         if (ret < 0)
1347                 goto out;
1348         if (snapshot_removal_status == HS_PRE_RUNNING) {
1349                 ret = wait_for_remove_process();
1350                 if (ret < 0)
1351                         goto out;
1352                 if (snapshot_removal_status != HS_PRE_SUCCESS)
1353                         goto out;
1354         }
1355         ret = exec_rm();
1356         if (ret < 0)
1357                 goto out;
1358         ret = wait_for_remove_process();
1359         if (ret < 0)
1360                 goto out;
1361         if (snapshot_removal_status != HS_SUCCESS)
1362                 goto out;
1363         ret = post_remove_hook();
1364         if (ret < 0)
1365                 goto out;
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         ret = pre_create_hook();
1399         if (ret < 0)
1400                 return ret;
1401         if (create_pid) {
1402                 ret = wait_for_process(create_pid, &status);
1403                 if (ret < 0)
1404                         return ret;
1405                 ret = handle_pre_create_hook_exit(status);
1406                 if (ret <= 0) /* error, or pre-create failed */
1407                         return ret;
1408         }
1409         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1410         ret = create_snapshot(rsync_argv);
1411         if (ret < 0)
1412                 goto out;
1413         ret = wait_for_process(create_pid, &status);
1414         if (ret < 0)
1415                 goto out;
1416         ret = handle_rsync_exit(status);
1417         if (ret < 0)
1418                 goto out;
1419         post_create_hook();
1420         if (create_pid)
1421                 ret = wait_for_process(create_pid, &status);
1422 out:
1423         free_rsync_argv(rsync_argv);
1424         return ret;
1425 }
1426
1427 static int com_ls(void)
1428 {
1429         int i;
1430         struct snapshot_list sl;
1431         struct snapshot *s;
1432
1433         dss_get_snapshot_list(&sl);
1434         FOR_EACH_SNAPSHOT(s, i, &sl) {
1435                 int64_t d = 0;
1436                 if (s->flags & SS_COMPLETE)
1437                         d = (s->completion_time - s->creation_time) / 60;
1438                 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1439         };
1440         free_snapshot_list(&sl);
1441         return 1;
1442 }
1443
1444 static int setup_signal_handling(void)
1445 {
1446         int ret;
1447
1448         DSS_INFO_LOG("setting up signal handlers\n");
1449         signal_pipe = signal_init(); /* always successful */
1450         ret = install_sighandler(SIGINT);
1451         if (ret < 0)
1452                 return ret;
1453         ret = install_sighandler(SIGTERM);
1454         if (ret < 0)
1455                 return ret;
1456         return install_sighandler(SIGCHLD);
1457 }
1458
1459 /**
1460  * The main function of dss.
1461  *
1462  * \param argc Usual argument count.
1463  * \param argv Usual argument vector.
1464  */
1465 int main(int argc, char **argv)
1466 {
1467         int ret;
1468         struct cmdline_parser_params params = {
1469                 .override = 0,
1470                 .initialize = 1,
1471                 .check_required = 0,
1472                 .check_ambiguity = 0,
1473                 .print_errors = 1
1474         };
1475
1476         cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1477         ret = parse_config_file(0);
1478         if (ret < 0)
1479                 goto out;
1480         if (ret == 0) { /* no config file given */
1481                 /*
1482                  * Parse the command line options again, but this time check
1483                  * that all required options are given.
1484                  */
1485                 params = (struct cmdline_parser_params) {
1486                         .override = 1,
1487                         .initialize = 1,
1488                         .check_required = 1,
1489                         .check_ambiguity = 1,
1490                         .print_errors = 1
1491                 };
1492                 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1493         }
1494         if (conf.daemon_given)
1495                 daemon_init();
1496         ret = change_to_dest_dir();
1497         if (ret < 0)
1498                 goto out;
1499         dump_dss_config("startup");
1500         ret = setup_signal_handling();
1501         if (ret < 0)
1502                 goto out;
1503         ret = call_command_handler();
1504 out:
1505         if (ret < 0)
1506                 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1507         exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1508 }