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 #define COMMAND(x) static int com_ ##x(void);
 176 COMMANDS
 177 #undef COMMAND
 178 #define COMMAND(x) if (conf.x ##_given) return com_ ##x();
 179 static int call_command_handler(void)
 180 {
 181         COMMANDS
 182         DSS_EMERG_LOG("BUG: did not find command handler\n");
 183         return -E_BUG;
 184 }
 185 #undef COMMAND
 186 #undef COMMANDS
 187
 188 /**
 189  * The log function of dss.
 190  *
 191  * \param ll Loglevel.
 192  * \param fml Usual format string.
 193  *
 194  * All DSS_XXX_LOG() macros use this function.
 195  */
 196 __printf_2_3 void dss_log(int ll, const char* fmt,...)
 197 {
 198         va_list argp;
 199         FILE *outfd;
 200         struct tm *tm;
 201         time_t t1;
 202         char str[255] = "";
 203
 204         if (ll < conf.loglevel_arg)
 205                 return;
 206         outfd = logfile? logfile : stderr;
 207         time(&t1);
 208         tm = localtime(&t1);
 209         strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
 210         fprintf(outfd, "%s ", str);
 211         if (conf.loglevel_arg <= INFO)
 212                 fprintf(outfd, "%i: ", ll);
 213         va_start(argp, fmt);
 214         vfprintf(outfd, fmt, argp);
 215         va_end(argp);
 216 }
 217
 218 /**
 219  * Print a message either to stdout or to the log file.
 220  */
 221 static __printf_1_2 void dss_msg(const char* fmt,...)
 222 {
 223         FILE *outfd = conf.daemon_given? logfile : stdout;
 224         va_list argp;
 225         va_start(argp, fmt);
 226         vfprintf(outfd, fmt, argp);
 227         va_end(argp);
 228 }
 229
 230 static char *get_config_file_name(void)
 231 {
 232         char *home, *config_file;
 233
 234         if (conf.config_file_given)
 235                 return dss_strdup(conf.config_file_arg);
 236         home = get_homedir();
 237         config_file = make_message("%s/.dssrc", home);
 238         free(home);
 239         return config_file;
 240 }
 241
 242 static void dss_get_snapshot_list(struct snapshot_list *sl)
 243 {
 244         get_snapshot_list(sl, conf.unit_interval_arg, conf.num_intervals_arg);
 245 }
 246
 247 static int64_t compute_next_snapshot_time(void)
 248 {
 249         int64_t x = 0, now = get_current_time(), unit_interval
 250                 = 24 * 3600 * conf.unit_interval_arg, ret;
 251         unsigned wanted = desired_number_of_snapshots(0, conf.num_intervals_arg),
 252                 num_complete_snapshots = 0;
 253         int i;
 254         struct snapshot *s = NULL;
 255         struct snapshot_list sl;
 256
 257         dss_get_snapshot_list(&sl);
 258         FOR_EACH_SNAPSHOT(s, i, &sl) {
 259                 if (!(s->flags & SS_COMPLETE))
 260                         continue;
 261                 num_complete_snapshots++;
 262                 x += s->completion_time - s->creation_time;
 263         }
 264         assert(x >= 0);
 265
 266         ret = now;
 267         if (num_complete_snapshots == 0)
 268                 goto out;
 269         x /= num_complete_snapshots; /* avg time to create one snapshot */
 270         if (unit_interval < x * wanted) /* oops, no sleep at all */
 271                 goto out;
 272         ret = s->completion_time + unit_interval / wanted - x;
 273 out:
 274         free_snapshot_list(&sl);
 275         return ret;
 276 }
 277
 278 static inline void invalidate_next_snapshot_time(void)
 279 {
 280         next_snapshot_time = 0;
 281 }
 282
 283 static inline int next_snapshot_time_is_valid(void)
 284 {
 285         return next_snapshot_time != 0;
 286 }
 287
 288 static int next_snapshot_is_due(void)
 289 {
 290         int64_t now = get_current_time();
 291
 292         if (!next_snapshot_time_is_valid())
 293                 next_snapshot_time = compute_next_snapshot_time();
 294         if (next_snapshot_time <= now) {
 295                 DSS_DEBUG_LOG("next snapshot: now\n");
 296                 return 1;
 297         }
 298         DSS_DEBUG_LOG("next snapshot due in %" PRId64 " seconds\n",
 299                 next_snapshot_time - now);
 300         return 0;
 301 }
 302
 303 static int pre_create_hook(void)
 304 {
 305         int ret, fds[3] = {0, 0, 0};
 306
 307         assert(snapshot_creation_status == HS_READY);
 308         /* make sure that the next snapshot time will be recomputed */
 309         invalidate_next_snapshot_time();
 310         DSS_DEBUG_LOG("executing %s\n", conf.pre_create_hook_arg);
 311         ret = dss_exec_cmdline_pid(&create_pid,
 312                 conf.pre_create_hook_arg, fds);
 313         if (ret < 0)
 314                 return ret;
 315         snapshot_creation_status = HS_PRE_RUNNING;
 316         return ret;
 317 }
 318
 319 static int pre_remove_hook(struct snapshot *s, const char *why)
 320 {
 321         int ret, fds[3] = {0, 0, 0};
 322         char *cmd;
 323
 324         if (!s)
 325                 return 0;
 326         DSS_DEBUG_LOG("%s snapshot %s\n", why, s->name);
 327         assert(snapshot_removal_status == HS_READY);
 328         assert(remove_pid == 0);
 329         assert(!snapshot_currently_being_removed);
 330
 331         snapshot_currently_being_removed = dss_malloc(sizeof(struct snapshot));
 332         *snapshot_currently_being_removed = *s;
 333         snapshot_currently_being_removed->name = dss_strdup(s->name);
 334
 335         cmd = make_message("%s %s/%s", conf.pre_remove_hook_arg,
 336                 conf.dest_dir_arg, s->name);
 337         DSS_DEBUG_LOG("executing %s\n", cmd);
 338         ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
 339         free(cmd);
 340         if (ret < 0)
 341                 return ret;
 342         snapshot_removal_status = HS_PRE_RUNNING;
 343         return ret;
 344 }
 345
 346 static int exec_rm(void)
 347 {
 348         struct snapshot *s = snapshot_currently_being_removed;
 349         int fds[3] = {0, 0, 0};
 350         char *new_name = being_deleted_name(s);
 351         char *argv[] = {"rm", "-rf", new_name, NULL};
 352         int ret;
 353
 354         assert(snapshot_removal_status == HS_PRE_SUCCESS);
 355         assert(remove_pid == 0);
 356
 357         DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
 358         ret = dss_rename(s->name, new_name);
 359         if (ret < 0)
 360                 goto out;
 361         ret = dss_exec(&remove_pid, argv[0], argv, fds);
 362         if (ret < 0)
 363                 goto out;
 364         snapshot_removal_status = HS_RUNNING;
 365 out:
 366         free(new_name);
 367         return ret;
 368 }
 369
 370 static int snapshot_is_being_created(struct snapshot *s)
 371 {
 372         return s->creation_time == current_snapshot_creation_time;
 373 }
 374
 375 static struct snapshot *find_orphaned_snapshot(struct snapshot_list *sl)
 376 {
 377         struct snapshot *s;
 378         int i;
 379
 380         DSS_DEBUG_LOG("looking for orphaned snapshots\n");
 381         FOR_EACH_SNAPSHOT(s, i, sl) {
 382                 if (snapshot_is_being_created(s))
 383                         continue;
 384                 /*
 385                  * We know that no rm is currently running, so if s is marked
 386                  * as being deleted, a previously started rm must have failed.
 387                  */
 388                 if (s->flags & SS_BEING_DELETED)
 389                         return s;
 390
 391                 if (s->flags & SS_COMPLETE) /* good snapshot */
 392                         continue;
 393                 /*
 394                  * This snapshot is incomplete and it is not the snapshot
 395                  * currently being created. However, we must not remove it if
 396                  * rsync is about to be restarted. As only the newest snapshot
 397                  * can be restarted, this snapshot is orphaned if it is not the
 398                  * newest snapshot or if we are not about to restart rsync.
 399                  */
 400                 if (get_newest_snapshot(sl) != s)
 401                         return s;
 402                 if (snapshot_creation_status != HS_NEEDS_RESTART)
 403                         return s;
 404         }
 405         /* no orphaned snapshots */
 406         return NULL;
 407 }
 408
 409 static int is_reference_snapshot(struct snapshot *s)
 410 {
 411         if (!name_of_reference_snapshot)
 412                 return 0;
 413         return strcmp(s->name, name_of_reference_snapshot)? 0 : 1;
 414 }
 415
 416 /*
 417  * return: 0: no redundant snapshots, 1: rm process started, negative: error
 418  */
 419 static struct snapshot *find_redundant_snapshot(struct snapshot_list *sl)
 420 {
 421         int i, interval;
 422         struct snapshot *s;
 423         unsigned missing = 0;
 424
 425         DSS_DEBUG_LOG("looking for intervals containing too many snapshots\n");
 426         for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
 427                 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
 428                 unsigned num = sl->interval_count[interval];
 429                 struct snapshot *victim = NULL, *prev = NULL;
 430                 int64_t score = LONG_MAX;
 431
 432                 if (keep >= num)
 433                         missing += keep - num;
 434 //              DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
 435 //                      interval, keep, num, missing);
 436                 if (keep + missing >= num)
 437                         continue;
 438                 /* redundant snapshot in this interval, pick snapshot with lowest score */
 439                 FOR_EACH_SNAPSHOT(s, i, sl) {
 440                         int64_t this_score;
 441
 442                         if (snapshot_is_being_created(s))
 443                                 continue;
 444                         if (is_reference_snapshot(s))
 445                                 continue;
 446                         //DSS_DEBUG_LOG("checking %s\n", s->name);
 447                         if (s->interval > interval) {
 448                                 prev = s;
 449                                 continue;
 450                         }
 451                         if (s->interval < interval)
 452                                 break;
 453                         if (!victim) {
 454                                 victim = s;
 455                                 prev = s;
 456                                 continue;
 457                         }
 458                         assert(prev);
 459                         /* check if s is a better victim */
 460                         this_score = s->creation_time - prev->creation_time;
 461                         assert(this_score >= 0);
 462                         //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
 463                         if (this_score < score) {
 464                                 score = this_score;
 465                                 victim = s;
 466                         }
 467                         prev = s;
 468                 }
 469                 assert(victim);
 470                 return victim;
 471         }
 472         return NULL;
 473 }
 474
 475 static struct snapshot *find_outdated_snapshot(struct snapshot_list *sl)
 476 {
 477         int i;
 478         struct snapshot *s;
 479
 480         DSS_DEBUG_LOG("looking for snapshots belonging to intervals >= %d\n",
 481                 conf.num_intervals_arg);
 482         FOR_EACH_SNAPSHOT(s, i, sl) {
 483                 if (snapshot_is_being_created(s))
 484                         continue;
 485                 if (is_reference_snapshot(s))
 486                         continue;
 487                 if (s->interval < conf.num_intervals_arg)
 488                         continue;
 489                 return s;
 490         }
 491         return NULL;
 492 }
 493
 494 struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
 495 {
 496         int i;
 497         struct snapshot *s;
 498         FOR_EACH_SNAPSHOT(s, i, sl) {
 499                 if (snapshot_is_being_created(s))
 500                         continue;
 501                 if (is_reference_snapshot(s))
 502                         continue;
 503                 DSS_INFO_LOG("oldest removable snapshot: %s\n", s->name);
 504                 return s;
 505         }
 506         return NULL;
 507 }
 508
 509 static int rename_incomplete_snapshot(int64_t start)
 510 {
 511         char *old_name;
 512         int ret;
 513
 514         free(path_to_last_complete_snapshot);
 515         ret = complete_name(start, get_current_time(),
 516                 &path_to_last_complete_snapshot);
 517         if (ret < 0)
 518                 return ret;
 519         old_name = incomplete_name(start);
 520         ret = dss_rename(old_name, path_to_last_complete_snapshot);
 521         if (ret >= 0)
 522                 DSS_NOTICE_LOG("%s -> %s\n", old_name,
 523                         path_to_last_complete_snapshot);
 524         free(old_name);
 525         return ret;
 526 }
 527
 528 static int try_to_free_disk_space(void)
 529 {
 530         int ret;
 531         struct snapshot_list sl;
 532         struct snapshot *victim;
 533         struct timeval now;
 534         const char *why;
 535         int low_disk_space;
 536
 537         ret = disk_space_low(NULL);
 538         if (ret < 0)
 539                 return ret;
 540         low_disk_space = ret;
 541         gettimeofday(&now, NULL);
 542         if (tv_diff(&next_removal_check, &now, NULL) > 0)
 543                 return 0;
 544         if (!low_disk_space) {
 545                 if (conf.keep_redundant_given)
 546                         return 0;
 547                 if (snapshot_creation_status != HS_READY)
 548                         return 0;
 549                 if (next_snapshot_is_due())
 550                         return 0;
 551         }
 552         dss_get_snapshot_list(&sl);
 553         ret = 0;
 554         if (!low_disk_space && sl.num_snapshots <= 1)
 555                 goto out;
 556         why = "outdated";
 557         victim = find_outdated_snapshot(&sl);
 558         if (victim)
 559                 goto remove;
 560         why = "redundant";
 561         victim = find_redundant_snapshot(&sl);
 562         if (victim)
 563                 goto remove;
 564         /* try harder only if disk space is low */
 565         if (!low_disk_space)
 566                 goto out;
 567         why = "orphaned";
 568         victim = find_orphaned_snapshot(&sl);
 569         if (victim)
 570                 goto remove;
 571         DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
 572         victim = find_oldest_removable_snapshot(&sl);
 573         if (victim)
 574                 goto remove;
 575         DSS_CRIT_LOG("uhuhu: disk space low and nothing to remove\n");
 576         ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
 577         goto out;
 578 remove:
 579         ret = pre_remove_hook(victim, why);
 580 out:
 581         free_snapshot_list(&sl);
 582         return ret;
 583 }
 584
 585 static int post_create_hook(void)
 586 {
 587         int ret, fds[3] = {0, 0, 0};
 588         char *cmd;
 589
 590         cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
 591                 conf.dest_dir_arg, path_to_last_complete_snapshot);
 592         DSS_NOTICE_LOG("executing %s\n", cmd);
 593         ret = dss_exec_cmdline_pid(&create_pid, cmd, fds);
 594         free(cmd);
 595         if (ret < 0)
 596                 return ret;
 597         snapshot_creation_status = HS_POST_RUNNING;
 598         return ret;
 599 }
 600
 601 static int post_remove_hook(void)
 602 {
 603         int ret, fds[3] = {0, 0, 0};
 604         char *cmd;
 605         struct snapshot *s = snapshot_currently_being_removed;
 606
 607         assert(s);
 608
 609         cmd = make_message("%s %s/%s", conf.post_remove_hook_arg,
 610                 conf.dest_dir_arg, s->name);
 611         DSS_NOTICE_LOG("executing %s\n", cmd);
 612         ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
 613         free(cmd);
 614         if (ret < 0)
 615                 return ret;
 616         snapshot_removal_status = HS_POST_RUNNING;
 617         return ret;
 618 }
 619
 620 static void dss_kill(pid_t pid, int sig, const char *msg)
 621 {
 622         const char *signame, *process_name;
 623
 624         if (pid == 0)
 625                 return;
 626         switch (sig) {
 627         case SIGTERM: signame = "TERM"; break;
 628         case SIGSTOP: signame = "STOP"; break;
 629         case SIGCONT: signame = "CONT"; break;
 630         default: signame = "????";
 631         }
 632
 633         if (pid == create_pid)
 634                 process_name = "create";
 635         else if (pid == remove_pid)
 636                 process_name = "remove";
 637         else process_name = "??????";
 638
 639         if (msg)
 640                 DSS_INFO_LOG("%s\n", msg);
 641         DSS_DEBUG_LOG("sending signal %d (%s) to pid %d (%s process)\n",
 642                 sig, signame, (int)pid, process_name);
 643         if (kill(pid, sig) >= 0)
 644                 return;
 645         DSS_INFO_LOG("failed to send signal %d (%s) to pid %d (%s process)\n",
 646                 sig, signame, (int)pid, process_name);
 647 }
 648
 649 static void stop_create_process(void)
 650 {
 651         if (create_process_stopped)
 652                 return;
 653         dss_kill(create_pid, SIGSTOP, "suspending create process");
 654         create_process_stopped = 1;
 655 }
 656
 657 static void restart_create_process(void)
 658 {
 659         if (!create_process_stopped)
 660                 return;
 661         dss_kill(create_pid, SIGCONT, "resuming create process");
 662         create_process_stopped = 0;
 663 }
 664
 665 /**
 666  * Print a log message about the exit status of a child.
 667  */
 668 static void log_termination_msg(pid_t pid, int status)
 669 {
 670         if (WIFEXITED(status))
 671                 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
 672                         WEXITSTATUS(status));
 673         else if (WIFSIGNALED(status))
 674                 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
 675                         WTERMSIG(status));
 676         else
 677                 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
 678 }
 679
 680 static int wait_for_process(pid_t pid, int *status)
 681 {
 682         int ret;
 683
 684         DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
 685         for (;;) {
 686                 fd_set rfds;
 687
 688                 FD_ZERO(&rfds);
 689                 FD_SET(signal_pipe, &rfds);
 690                 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
 691                 if (ret < 0)
 692                         break;
 693                 ret = next_signal();
 694                 if (!ret)
 695                         continue;
 696                 if (ret == SIGCHLD) {
 697                         ret = waitpid(pid, status, 0);
 698                         if (ret >= 0)
 699                                 break;
 700                         if (errno != EINTR) { /* error */
 701                                 ret = -ERRNO_TO_DSS_ERROR(errno);
 702                                 break;
 703                         }
 704                 }
 705                 /* SIGINT or SIGTERM */
 706                 dss_kill(pid, SIGTERM, "killing child process");
 707         }
 708         if (ret < 0)
 709                 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
 710         else
 711                 log_termination_msg(pid, *status);
 712         return ret;
 713 }
 714
 715 static void handle_pre_remove_exit(int status)
 716 {
 717         if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 718                 snapshot_removal_status = HS_READY;
 719                 gettimeofday(&next_removal_check, NULL);
 720                 next_removal_check.tv_sec += 60;
 721                 return;
 722         }
 723         snapshot_removal_status = HS_PRE_SUCCESS;
 724 }
 725
 726 static int handle_rm_exit(int status)
 727 {
 728         if (!WIFEXITED(status)) {
 729                 snapshot_removal_status = HS_READY;
 730                 return -E_INVOLUNTARY_EXIT;
 731         }
 732         if (WEXITSTATUS(status)) {
 733                 snapshot_removal_status = HS_READY;
 734                 return -E_BAD_EXIT_CODE;
 735         }
 736         snapshot_removal_status = HS_SUCCESS;
 737         return 1;
 738 }
 739
 740 static void handle_post_remove_exit(void)
 741 {
 742         snapshot_removal_status = HS_READY;
 743 }
 744
 745 static int handle_remove_exit(int status)
 746 {
 747         int ret;
 748         struct snapshot *s = snapshot_currently_being_removed;
 749
 750         assert(s);
 751         switch (snapshot_removal_status) {
 752         case HS_PRE_RUNNING:
 753                 handle_pre_remove_exit(status);
 754                 ret = 1;
 755                 break;
 756         case HS_RUNNING:
 757                 ret = handle_rm_exit(status);
 758                 break;
 759         case HS_POST_RUNNING:
 760                 handle_post_remove_exit();
 761                 ret = 1;
 762                 break;
 763         default:
 764                 ret = -E_BUG;
 765         }
 766         if (snapshot_removal_status == HS_READY) {
 767                 free(s->name);
 768                 free(s);
 769                 snapshot_currently_being_removed = NULL;
 770         }
 771         remove_pid = 0;
 772         return ret;
 773 }
 774
 775 static int wait_for_remove_process(void)
 776 {
 777         int status, ret;
 778
 779         assert(remove_pid);
 780         assert(
 781                 snapshot_removal_status == HS_PRE_RUNNING ||
 782                 snapshot_removal_status == HS_RUNNING ||
 783                 snapshot_removal_status == HS_POST_RUNNING
 784         );
 785         ret = wait_for_process(remove_pid, &status);
 786         if (ret < 0)
 787                 return ret;
 788         return handle_remove_exit(status);
 789 }
 790
 791 static int handle_rsync_exit(int status)
 792 {
 793         int es, ret;
 794
 795         if (!WIFEXITED(status)) {
 796                 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)create_pid);
 797                 ret = -E_INVOLUNTARY_EXIT;
 798                 snapshot_creation_status = HS_READY;
 799                 goto out;
 800         }
 801         es = WEXITSTATUS(status);
 802         /*
 803          * Restart rsync on non-fatal errors:
 804          * 12: Error in rsync protocol data stream
 805          * 13: Errors with program diagnostics
 806          */
 807         if (es == 12 || es == 13) {
 808                 DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
 809                         (int)create_pid, es);
 810                 snapshot_creation_status = HS_NEEDS_RESTART;
 811                 next_snapshot_time = get_current_time() + 60;
 812                 ret = 1;
 813                 goto out;
 814         }
 815         if (es != 0 && es != 23 && es != 24) {
 816                 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)create_pid, es);
 817                 ret = -E_BAD_EXIT_CODE;
 818                 snapshot_creation_status = HS_READY;
 819                 goto out;
 820         }
 821         ret = rename_incomplete_snapshot(current_snapshot_creation_time);
 822         if (ret < 0)
 823                 goto out;
 824         snapshot_creation_status = HS_SUCCESS;
 825         free(name_of_reference_snapshot);
 826         name_of_reference_snapshot = NULL;
 827 out:
 828         create_process_stopped = 0;
 829         return ret;
 830 }
 831
 832 static int handle_pre_create_hook_exit(int status)
 833 {
 834         int es, ret;
 835         static int warn_count;
 836
 837         if (!WIFEXITED(status)) {
 838                 snapshot_creation_status = HS_READY;
 839                 ret = -E_INVOLUNTARY_EXIT;
 840                 goto out;
 841         }
 842         es = WEXITSTATUS(status);
 843         if (es) {
 844                 if (!warn_count--) {
 845                         DSS_NOTICE_LOG("pre_create_hook %s returned %d\n",
 846                                 conf.pre_create_hook_arg, es);
 847                         DSS_NOTICE_LOG("deferring snapshot creation...\n");
 848                         warn_count = 60; /* warn only once per hour */
 849                 }
 850                 next_snapshot_time = get_current_time() + 60;
 851                 snapshot_creation_status = HS_READY;
 852                 ret = 0;
 853                 goto out;
 854         }
 855         warn_count = 0;
 856         snapshot_creation_status = HS_PRE_SUCCESS;
 857         ret = 1;
 858 out:
 859         return ret;
 860 }
 861
 862 static int handle_sigchld(void)
 863 {
 864         pid_t pid;
 865         int status, ret = reap_child(&pid, &status);
 866
 867         if (ret <= 0)
 868                 return ret;
 869
 870         if (pid == create_pid) {
 871                 switch (snapshot_creation_status) {
 872                 case HS_PRE_RUNNING:
 873                         ret = handle_pre_create_hook_exit(status);
 874                         break;
 875                 case HS_RUNNING:
 876                         ret = handle_rsync_exit(status);
 877                         break;
 878                 case HS_POST_RUNNING:
 879                         snapshot_creation_status = HS_READY;
 880                         ret = 1;
 881                         break;
 882                 default:
 883                         DSS_EMERG_LOG("BUG: create can't die in status %d\n",
 884                                 snapshot_creation_status);
 885                         return -E_BUG;
 886                 }
 887                 create_pid = 0;
 888                 return ret;
 889         }
 890         if (pid == remove_pid) {
 891                 ret = handle_remove_exit(status);
 892                 if (ret < 0)
 893                         return ret;
 894                 return ret;
 895         }
 896         DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
 897         return -E_BUG;
 898 }
 899
 900 static int check_config(void)
 901 {
 902         if (conf.unit_interval_arg <= 0) {
 903                 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
 904                 return -E_INVALID_NUMBER;
 905         }
 906         DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
 907         if (conf.num_intervals_arg <= 0) {
 908                 DSS_ERROR_LOG("bad number of intervals  %i\n", conf.num_intervals_arg);
 909                 return -E_INVALID_NUMBER;
 910         }
 911         DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
 912         return 1;
 913 }
 914
 915 /*
 916  * Returns < 0 on errors, 0 if no config file is given and > 0 if the config
 917  * file was read successfully.
 918  */
 919 static int parse_config_file(int override)
 920 {
 921         int ret, config_file_exists;
 922         char *config_file = get_config_file_name();
 923         struct stat statbuf;
 924         char *old_logfile_arg = NULL;
 925         int old_daemon_given = 0;
 926
 927         if (override) { /* SIGHUP */
 928                 if (conf.logfile_given)
 929                         old_logfile_arg = dss_strdup(conf.logfile_arg);
 930                 old_daemon_given = conf.daemon_given;
 931         }
 932
 933         config_file_exists = !stat(config_file, &statbuf);
 934         if (!config_file_exists && conf.config_file_given) {
 935                 ret = -ERRNO_TO_DSS_ERROR(errno);
 936                 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
 937                 goto out;
 938         }
 939         if (config_file_exists) {
 940                 struct cmdline_parser_params params = {
 941                         .override = override,
 942                         .initialize = 0,
 943                         .check_required = 1,
 944                         .check_ambiguity = 0,
 945                         .print_errors = 1
 946                 };
 947                 if (override) { /* invalidate all rsync options */
 948                         int i;
 949
 950                         for (i = 0; i < conf.rsync_option_given; i++) {
 951                                 free(conf.rsync_option_arg[i]);
 952                                 conf.rsync_option_arg[i] = NULL;
 953                         }
 954                         conf.rsync_option_given = 0;
 955                 }
 956                 cmdline_parser_config_file(config_file, &conf, &params);
 957         }
 958         ret = check_config();
 959         if (ret < 0)
 960                 goto out;
 961         if (override) {
 962                 /* don't change daemon mode on SIGHUP */
 963                 conf.daemon_given = old_daemon_given;
 964                 close_log(logfile);
 965                 logfile = NULL;
 966                 if (conf.logfile_given)
 967                         free(old_logfile_arg);
 968                 else if (conf.daemon_given) { /* re-use old logfile */
 969                         conf.logfile_arg = old_logfile_arg;
 970                         conf.logfile_given = 1;
 971                 }
 972         }
 973         if (conf.logfile_given && conf.run_given && conf.daemon_given) {
 974                 logfile = open_log(conf.logfile_arg);
 975                 log_welcome(conf.loglevel_arg);
 976         }
 977         DSS_DEBUG_LOG("loglevel: %d\n", conf.loglevel_arg);
 978         ret = config_file_exists;
 979 out:
 980         free(config_file);
 981         if (ret < 0)
 982                 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
 983         return ret;
 984 }
 985
 986 static int change_to_dest_dir(void)
 987 {
 988         DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
 989         return dss_chdir(conf.dest_dir_arg);
 990 }
 991
 992 static int handle_sighup(void)
 993 {
 994         int ret;
 995
 996         DSS_NOTICE_LOG("SIGHUP, re-reading config\n");
 997         dump_dss_config("old");
 998         ret = parse_config_file(1);
 999         if (ret < 0)
1000                 return ret;
1001         dump_dss_config("reloaded");
1002         invalidate_next_snapshot_time();
1003         return change_to_dest_dir();
1004 }
1005
1006 static int handle_signal(void)
1007 {
1008         int sig, ret = next_signal();
1009
1010         if (ret <= 0)
1011                 goto out;
1012         sig = ret;
1013         switch (sig) {
1014         case SIGINT:
1015         case SIGTERM:
1016                 restart_create_process();
1017                 dss_kill(create_pid, SIGTERM, NULL);
1018                 dss_kill(remove_pid, SIGTERM, NULL);
1019                 ret = -E_SIGNAL;
1020                 break;
1021         case SIGHUP:
1022                 ret = handle_sighup();
1023                 break;
1024         case SIGCHLD:
1025                 ret = handle_sigchld();
1026                 break;
1027         }
1028 out:
1029         if (ret < 0)
1030                 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
1031         return ret;
1032 }
1033
1034 /*
1035  * We can not use rsync locally if the local user is different from the remote
1036  * user or if the src dir is not on the local host (or both).
1037  */
1038 static int use_rsync_locally(char *logname)
1039 {
1040         char *h = conf.remote_host_arg;
1041
1042         if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
1043                 return 0;
1044         if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
1045                 return 0;
1046         return 1;
1047 }
1048
1049 static int rename_resume_snap(int64_t creation_time)
1050 {
1051         struct snapshot_list sl = {.num_snapshots = 0};
1052         struct snapshot *s = NULL;
1053         char *new_name = incomplete_name(creation_time);
1054         int ret;
1055         const char *why;
1056
1057         ret = 0;
1058         if (conf.no_resume_given)
1059                 goto out;
1060         dss_get_snapshot_list(&sl);
1061         /*
1062          * Snapshot recycling: We first look at the newest snapshot. If this
1063          * snapshot happens to be incomplete, the last rsync process was
1064          * aborted and we reuse this one. Otherwise we look at snapshots which
1065          * could be removed (outdated and redundant snapshots) as candidates
1066          * for recycling. If no outdated/redundant snapshot exists, we check if
1067          * there is an orphaned snapshot, which likely is useless anyway.
1068          *
1069          * Only if no existing snapshot is suitable for recycling, we bite the
1070          * bullet and create a new one.
1071          */
1072         s = get_newest_snapshot(&sl);
1073         if (!s) /* no snapshots at all */
1074                 goto out;
1075         /* re-use last snapshot if it is incomplete */
1076         why = "aborted";
1077         if ((s->flags & SS_COMPLETE) == 0)
1078                 goto out;
1079         why = "outdated";
1080         s = find_outdated_snapshot(&sl);
1081         if (s)
1082                 goto out;
1083         why = "redundant";
1084         s = find_redundant_snapshot(&sl);
1085         if (s)
1086                 goto out;
1087         why = "orphaned";
1088         s = find_orphaned_snapshot(&sl);
1089 out:
1090         if (s) {
1091                 DSS_INFO_LOG("reusing %s snapshot %s\n", why, s->name);
1092                 ret = dss_rename(s->name, new_name);
1093         }
1094         if (ret >= 0)
1095                 DSS_NOTICE_LOG("creating new snapshot %s\n", new_name);
1096         free(new_name);
1097         free_snapshot_list(&sl);
1098         return ret;
1099 }
1100
1101 static void create_rsync_argv(char ***argv, int64_t *num)
1102 {
1103         char *logname;
1104         int i = 0, j;
1105         struct snapshot_list sl;
1106
1107         dss_get_snapshot_list(&sl);
1108         assert(!name_of_reference_snapshot);
1109         name_of_reference_snapshot = name_of_newest_complete_snapshot(&sl);
1110         free_snapshot_list(&sl);
1111
1112         *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
1113         (*argv)[i++] = dss_strdup("rsync");
1114         (*argv)[i++] = dss_strdup("-aq");
1115         (*argv)[i++] = dss_strdup("--delete");
1116         for (j = 0; j < conf.rsync_option_given; j++)
1117                 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
1118         if (name_of_reference_snapshot) {
1119                 DSS_INFO_LOG("using %s as reference\n", name_of_reference_snapshot);
1120                 (*argv)[i++] = make_message("--link-dest=../%s",
1121                         name_of_reference_snapshot);
1122         } else
1123                 DSS_INFO_LOG("no suitable reference snapshot found\n");
1124         logname = dss_logname();
1125         if (use_rsync_locally(logname))
1126                 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
1127         else
1128                 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
1129                         conf.remote_user_arg : logname,
1130                         conf.remote_host_arg, conf.source_dir_arg);
1131         free(logname);
1132         *num = get_current_time();
1133         (*argv)[i++] = incomplete_name(*num);
1134         (*argv)[i++] = NULL;
1135         for (j = 0; j < i; j++)
1136                 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
1137 }
1138
1139 static void free_rsync_argv(char **argv)
1140 {
1141         int i;
1142
1143         if (!argv)
1144                 return;
1145         for (i = 0; argv[i]; i++)
1146                 free(argv[i]);
1147         free(argv);
1148 }
1149
1150 static int create_snapshot(char **argv)
1151 {
1152         int ret, fds[3] = {0, 0, 0};
1153
1154         ret = rename_resume_snap(current_snapshot_creation_time);
1155         if (ret < 0)
1156                 return ret;
1157         ret = dss_exec(&create_pid, argv[0], argv, fds);
1158         if (ret < 0)
1159                 return ret;
1160         snapshot_creation_status = HS_RUNNING;
1161         return ret;
1162 }
1163
1164 static int select_loop(void)
1165 {
1166         int ret;
1167         /* check every 60 seconds for free disk space */
1168         struct timeval tv;
1169         char **rsync_argv = NULL;
1170
1171         for (;;) {
1172                 fd_set rfds;
1173                 struct timeval *tvp;
1174
1175                 if (remove_pid)
1176                         tvp = NULL; /* sleep until rm hook/process dies */
1177                 else { /* sleep one minute */
1178                         tv.tv_sec = 60;
1179                         tv.tv_usec = 0;
1180                         tvp = &tv;
1181                 }
1182                 FD_ZERO(&rfds);
1183                 FD_SET(signal_pipe, &rfds);
1184                 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
1185                 if (ret < 0)
1186                         goto out;
1187                 if (FD_ISSET(signal_pipe, &rfds)) {
1188                         ret = handle_signal();
1189                         if (ret < 0)
1190                                 goto out;
1191                 }
1192                 if (remove_pid)
1193                         continue;
1194                 if (snapshot_removal_status == HS_PRE_SUCCESS) {
1195                         ret = exec_rm();
1196                         if (ret < 0)
1197                                 goto out;
1198                         continue;
1199                 }
1200                 if (snapshot_removal_status == HS_SUCCESS) {
1201                         ret = post_remove_hook();
1202                         if (ret < 0)
1203                                 goto out;
1204                         continue;
1205                 }
1206                 ret = try_to_free_disk_space();
1207                 if (ret < 0)
1208                         goto out;
1209                 if (snapshot_removal_status != HS_READY) {
1210                         stop_create_process();
1211                         continue;
1212                 }
1213                 restart_create_process();
1214                 switch (snapshot_creation_status) {
1215                 case HS_READY:
1216                         if (!next_snapshot_is_due())
1217                                 continue;
1218                         ret = pre_create_hook();
1219                         if (ret < 0)
1220                                 goto out;
1221                         continue;
1222                 case HS_PRE_RUNNING:
1223                 case HS_RUNNING:
1224                 case HS_POST_RUNNING:
1225                         continue;
1226                 case HS_PRE_SUCCESS:
1227                         if (!name_of_reference_snapshot) {
1228                                 free_rsync_argv(rsync_argv);
1229                                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1230                         }
1231                         ret = create_snapshot(rsync_argv);
1232                         if (ret < 0)
1233                                 goto out;
1234                         continue;
1235                 case HS_NEEDS_RESTART:
1236                         if (!next_snapshot_is_due())
1237                                 continue;
1238                         ret = create_snapshot(rsync_argv);
1239                         if (ret < 0)
1240                                 goto out;
1241                         continue;
1242                 case HS_SUCCESS:
1243                         ret = post_create_hook();
1244                         if (ret < 0)
1245                                 goto out;
1246                         continue;
1247                 }
1248         }
1249 out:
1250         return ret;
1251 }
1252
1253 static void exit_hook(int exit_code)
1254 {
1255         int fds[3] = {0, 0, 0};
1256         char *argv[] = {conf.exit_hook_arg, dss_strerror(-exit_code), NULL};
1257         pid_t pid;
1258
1259         DSS_NOTICE_LOG("executing %s %s\n", argv[0], argv[1]);
1260         dss_exec(&pid, conf.exit_hook_arg, argv, fds);
1261 }
1262
1263 static void lock_dss_or_die(void)
1264 {
1265         char *config_file = get_config_file_name();
1266         int ret = lock_dss(config_file);
1267
1268         free(config_file);
1269         if (ret < 0) {
1270                 DSS_EMERG_LOG("failed to lock: %s\n", dss_strerror(-ret));
1271                 exit(EXIT_FAILURE);
1272         }
1273 }
1274
1275 static int com_run(void)
1276 {
1277         int ret;
1278
1279         lock_dss_or_die();
1280         if (conf.dry_run_given) {
1281                 DSS_ERROR_LOG("dry_run not supported by this command\n");
1282                 return -E_SYNTAX;
1283         }
1284         ret = install_sighandler(SIGHUP);
1285         if (ret < 0)
1286                 return ret;
1287         ret = select_loop();
1288         if (ret >= 0) /* impossible */
1289                 ret = -E_BUG;
1290         exit_hook(ret);
1291         return ret;
1292 }
1293
1294 static int com_prune(void)
1295 {
1296         int ret;
1297         struct snapshot_list sl;
1298         struct snapshot *victim;
1299         struct disk_space ds;
1300         const char *why;
1301
1302         lock_dss_or_die();
1303         ret = get_disk_space(".", &ds);
1304         if (ret < 0)
1305                 return ret;
1306         log_disk_space(&ds);
1307         dss_get_snapshot_list(&sl);
1308         why = "outdated";
1309         victim = find_outdated_snapshot(&sl);
1310         if (victim)
1311                 goto rm;
1312         why = "redundant";
1313         victim = find_redundant_snapshot(&sl);
1314         if (victim)
1315                 goto rm;
1316         ret = 0;
1317         goto out;
1318 rm:
1319         if (conf.dry_run_given) {
1320                 dss_msg("%s snapshot %s (interval = %i)\n",
1321                         why, victim->name, victim->interval);
1322                 ret = 0;
1323                 goto out;
1324         }
1325         ret = pre_remove_hook(victim, why);
1326         if (ret < 0)
1327                 goto out;
1328         if (snapshot_removal_status == HS_PRE_RUNNING) {
1329                 ret = wait_for_remove_process();
1330                 if (ret < 0)
1331                         goto out;
1332                 if (snapshot_removal_status != HS_PRE_SUCCESS)
1333                         goto out;
1334         }
1335         ret = exec_rm();
1336         if (ret < 0)
1337                 goto out;
1338         ret = wait_for_remove_process();
1339         if (ret < 0)
1340                 goto out;
1341         if (snapshot_removal_status != HS_SUCCESS)
1342                 goto out;
1343         ret = post_remove_hook();
1344         if (ret < 0)
1345                 goto out;
1346         if (snapshot_removal_status != HS_POST_RUNNING)
1347                 goto out;
1348         ret = wait_for_remove_process();
1349         if (ret < 0)
1350                 goto out;
1351         ret = 1;
1352 out:
1353         free_snapshot_list(&sl);
1354         return ret;
1355 }
1356
1357 static int com_create(void)
1358 {
1359         int ret, status;
1360         char **rsync_argv;
1361
1362         lock_dss_or_die();
1363         if (conf.dry_run_given) {
1364                 int i;
1365                 char *msg = NULL;
1366                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1367                 for (i = 0; rsync_argv[i]; i++) {
1368                         char *tmp = msg;
1369                         msg = make_message("%s%s%s", tmp? tmp : "",
1370                                 tmp? " " : "", rsync_argv[i]);
1371                         free(tmp);
1372                 }
1373                 free_rsync_argv(rsync_argv);
1374                 dss_msg("%s\n", msg);
1375                 free(msg);
1376                 return 1;
1377         }
1378         ret = pre_create_hook();
1379         if (ret < 0)
1380                 return ret;
1381         if (create_pid) {
1382                 ret = wait_for_process(create_pid, &status);
1383                 if (ret < 0)
1384                         return ret;
1385                 ret = handle_pre_create_hook_exit(status);
1386                 if (ret <= 0) /* error, or pre-create failed */
1387                         return ret;
1388         }
1389         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1390         ret = create_snapshot(rsync_argv);
1391         if (ret < 0)
1392                 goto out;
1393         ret = wait_for_process(create_pid, &status);
1394         if (ret < 0)
1395                 goto out;
1396         ret = handle_rsync_exit(status);
1397         if (ret < 0)
1398                 goto out;
1399         post_create_hook();
1400         if (create_pid)
1401                 ret = wait_for_process(create_pid, &status);
1402 out:
1403         free_rsync_argv(rsync_argv);
1404         return ret;
1405 }
1406
1407 static int com_ls(void)
1408 {
1409         int i;
1410         struct snapshot_list sl;
1411         struct snapshot *s;
1412
1413         dss_get_snapshot_list(&sl);
1414         FOR_EACH_SNAPSHOT(s, i, &sl) {
1415                 int64_t d = 0;
1416                 if (s->flags & SS_COMPLETE)
1417                         d = (s->completion_time - s->creation_time) / 60;
1418                 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1419         };
1420         free_snapshot_list(&sl);
1421         return 1;
1422 }
1423
1424 static int setup_signal_handling(void)
1425 {
1426         int ret;
1427
1428         DSS_INFO_LOG("setting up signal handlers\n");
1429         signal_pipe = signal_init(); /* always successful */
1430         ret = install_sighandler(SIGINT);
1431         if (ret < 0)
1432                 return ret;
1433         ret = install_sighandler(SIGTERM);
1434         if (ret < 0)
1435                 return ret;
1436         return install_sighandler(SIGCHLD);
1437 }
1438
1439 /**
1440  * The main function of dss.
1441  *
1442  * \param argc Usual argument count.
1443  * \param argv Usual argument vector.
1444  */
1445 int main(int argc, char **argv)
1446 {
1447         int ret;
1448         struct cmdline_parser_params params = {
1449                 .override = 0,
1450                 .initialize = 1,
1451                 .check_required = 0,
1452                 .check_ambiguity = 0,
1453                 .print_errors = 1
1454         };
1455
1456         cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1457         ret = parse_config_file(0);
1458         if (ret < 0)
1459                 goto out;
1460         if (ret == 0) { /* no config file given */
1461                 /*
1462                  * Parse the command line options again, but this time check
1463                  * that all required options are given.
1464                  */
1465                 params = (struct cmdline_parser_params) {
1466                         .override = 1,
1467                         .initialize = 1,
1468                         .check_required = 1,
1469                         .check_ambiguity = 1,
1470                         .print_errors = 1
1471                 };
1472                 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1473         }
1474         if (conf.daemon_given)
1475                 daemon_init();
1476         ret = change_to_dest_dir();
1477         if (ret < 0)
1478                 goto out;
1479         dump_dss_config("startup");
1480         ret = setup_signal_handling();
1481         if (ret < 0)
1482                 goto out;
1483         ret = call_command_handler();
1484 out:
1485         if (ret < 0)
1486                 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1487         exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1488 }