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
  37 /** Command line and config file options. */
  38 static struct gengetopt_args_info conf;
  39 /** Non-NULL if we log to a file. */
  40 static FILE *logfile;
  41 /** The read end of the signal pipe */
  42 static int signal_pipe;
  43 /** Process id of current pre-create-hook/rsync/post-create-hook process. */
  44 static pid_t create_pid;
  45 /** Whether the pre-create-hook/rsync/post-create-hook is currently stopped. */
  46 static int create_process_stopped;
  47 /** Process id of current pre-remove/rm/post-remove process. */
  48 static pid_t remove_pid;
  49 /** When the next snapshot is due. */
  50 static int64_t next_snapshot_time;
  51 /** When to try to remove something. */
  52 static struct timeval next_removal_check;
  53 /** Creation time of the snapshot currently being created. */
  54 static int64_t current_snapshot_creation_time;
  55 /** The snapshot currently being removed. */
  56 struct snapshot *snapshot_currently_being_removed;
  57 /** Needed by the post-create hook. */
  58 static char *path_to_last_complete_snapshot;
  59 static char *name_of_reference_snapshot;
  60 /** \sa \ref snap.h for details. */
  61 enum hook_status snapshot_creation_status;
  62 /** \sa \ref snap.h for details. */
  63 enum hook_status snapshot_removal_status;
  64
  65
  66 DEFINE_DSS_ERRLIST;
  67 static const char const *hook_status_description[] = {HOOK_STATUS_ARRAY};
  68
  69 /* may be called with ds == NULL. */
  70 static int disk_space_low(struct disk_space *ds)
  71 {
  72         struct disk_space ds_struct;
  73
  74         if (!ds) {
  75                 int ret = get_disk_space(".", &ds_struct);
  76                 if (ret < 0)
  77                         return ret;
  78                 ds = &ds_struct;
  79         }
  80         if (conf.min_free_mb_arg)
  81                 if (ds->free_mb < conf.min_free_mb_arg)
  82                         return 1;
  83         if (conf.min_free_percent_arg)
  84                 if (ds->percent_free < conf.min_free_percent_arg)
  85                         return 1;
  86         if (conf.min_free_percent_inodes_arg)
  87                 if (ds->percent_free_inodes < conf.min_free_percent_inodes_arg)
  88                         return 1;
  89         return 0;
  90 }
  91
  92 static void dump_dss_config(const char *msg)
  93 {
  94         const char dash[] = "-----------------------------";
  95         int ret;
  96         FILE *log = logfile? logfile : stderr;
  97         struct disk_space ds;
  98         int64_t now = get_current_time();
  99
 100         if (conf.loglevel_arg > INFO)
 101                 return;
 102
 103         fprintf(log, "%s <%s config> %s\n", dash, msg, dash);
 104         fprintf(log, "\n*** disk space ***\n\n");
 105         ret = get_disk_space(".", &ds);
 106         if (ret >= 0) {
 107                 DSS_INFO_LOG("disk space low: %s\n", disk_space_low(&ds)?
 108                         "yes" : "no");
 109                 log_disk_space(&ds);
 110         } else
 111                 DSS_ERROR_LOG("can not get free disk space: %s\n",
 112                         dss_strerror(-ret));
 113
 114         /* we continue on errors from get_disk_space */
 115
 116         fprintf(log, "\n*** command line and config file options ***\n\n");
 117         cmdline_parser_dump(log, &conf);
 118         fprintf(log, "\n*** internal state ***\n\n");
 119         fprintf(log,
 120                 "pid: %d\n"
 121                 "logile: %s\n"
 122                 "snapshot_currently_being_removed: %s\n"
 123                 "path_to_last_complete_snapshot: %s\n"
 124                 "reference_snapshot: %s\n"
 125                 "snapshot_creation_status: %s\n"
 126                 "snapshot_removal_status: %s\n"
 127                 ,
 128                 (int) getpid(),
 129                 logfile? conf.logfile_arg : "stderr",
 130                 snapshot_currently_being_removed?
 131                         snapshot_currently_being_removed->name : "(none)",
 132                 path_to_last_complete_snapshot?
 133                         path_to_last_complete_snapshot : "(none)",
 134                 name_of_reference_snapshot?
 135                         name_of_reference_snapshot : "(none)",
 136                 hook_status_description[snapshot_creation_status],
 137                 hook_status_description[snapshot_removal_status]
 138         );
 139         if (create_pid != 0)
 140                 fprintf(log,
 141                         "create_pid: %" PRId32 "\n"
 142                         "create process is %sstopped\n"
 143                         ,
 144                         create_pid,
 145                         create_process_stopped? "" : "not "
 146                 );
 147         if (remove_pid != 0)
 148                 fprintf(log, "remove_pid: %" PRId32 "\n", remove_pid);
 149         if (next_snapshot_time != 0)
 150                 fprintf(log, "next snapshot due in %" PRId64 " seconds\n",
 151                         next_snapshot_time - now);
 152         if (current_snapshot_creation_time != 0)
 153                 fprintf(log, "current_snapshot_creation_time: %"
 154                         PRId64 " (%" PRId64 " seconds ago)\n",
 155                         current_snapshot_creation_time,
 156                         now - current_snapshot_creation_time
 157                 );
 158         if (next_removal_check.tv_sec != 0) {
 159                 fprintf(log, "next removal check: %llu (%llu seconds ago)\n",
 160                         (long long unsigned)next_removal_check.tv_sec,
 161                         now - (long long unsigned)next_removal_check.tv_sec
 162                 );
 163
 164         }
 165         fprintf(log, "%s </%s config> %s\n", dash, msg, dash);
 166 }
 167
 168 /* a litte cpp magic helps to DRY */
 169 #define COMMANDS \
 170         COMMAND(ls) \
 171         COMMAND(create) \
 172         COMMAND(prune) \
 173         COMMAND(run)
 174 #define COMMAND(x) static int com_ ##x(void);
 175 COMMANDS
 176 #undef COMMAND
 177 #define COMMAND(x) if (conf.x ##_given) return com_ ##x();
 178 static int call_command_handler(void)
 179 {
 180         COMMANDS
 181         DSS_EMERG_LOG("BUG: did not find command handler\n");
 182         return -E_BUG;
 183 }
 184 #undef COMMAND
 185 #undef COMMANDS
 186
 187 /**
 188  * The log function of dss.
 189  *
 190  * \param ll Loglevel.
 191  * \param fml Usual format string.
 192  *
 193  * All DSS_XXX_LOG() macros use this function.
 194  */
 195 __printf_2_3 void dss_log(int ll, const char* fmt,...)
 196 {
 197         va_list argp;
 198         FILE *outfd;
 199         struct tm *tm;
 200         time_t t1;
 201         char str[255] = "";
 202
 203         if (ll < conf.loglevel_arg)
 204                 return;
 205         outfd = logfile? logfile : stderr;
 206         time(&t1);
 207         tm = localtime(&t1);
 208         strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
 209         fprintf(outfd, "%s ", str);
 210         if (conf.loglevel_arg <= INFO)
 211                 fprintf(outfd, "%i: ", ll);
 212         va_start(argp, fmt);
 213         vfprintf(outfd, fmt, argp);
 214         va_end(argp);
 215 }
 216
 217 /**
 218  * Print a message either to stdout or to the log file.
 219  */
 220 static __printf_1_2 void dss_msg(const char* fmt,...)
 221 {
 222         FILE *outfd = conf.daemon_given? logfile : stdout;
 223         va_list argp;
 224         va_start(argp, fmt);
 225         vfprintf(outfd, fmt, argp);
 226         va_end(argp);
 227 }
 228
 229 static void dss_get_snapshot_list(struct snapshot_list *sl)
 230 {
 231         get_snapshot_list(sl, conf.unit_interval_arg, conf.num_intervals_arg);
 232 }
 233
 234 static int64_t compute_next_snapshot_time(void)
 235 {
 236         int64_t x = 0, now = get_current_time(), unit_interval
 237                 = 24 * 3600 * conf.unit_interval_arg, ret;
 238         unsigned wanted = desired_number_of_snapshots(0, conf.num_intervals_arg),
 239                 num_complete_snapshots = 0;
 240         int i;
 241         struct snapshot *s = NULL;
 242         struct snapshot_list sl;
 243
 244         dss_get_snapshot_list(&sl);
 245         FOR_EACH_SNAPSHOT(s, i, &sl) {
 246                 if (!(s->flags & SS_COMPLETE))
 247                         continue;
 248                 num_complete_snapshots++;
 249                 x += s->completion_time - s->creation_time;
 250         }
 251         assert(x >= 0);
 252
 253         ret = now;
 254         if (num_complete_snapshots == 0)
 255                 goto out;
 256         x /= num_complete_snapshots; /* avg time to create one snapshot */
 257         if (unit_interval < x * wanted) /* oops, no sleep at all */
 258                 goto out;
 259         ret = s->completion_time + unit_interval / wanted - x;
 260 out:
 261         free_snapshot_list(&sl);
 262         return ret;
 263 }
 264
 265 static inline void invalidate_next_snapshot_time(void)
 266 {
 267         next_snapshot_time = 0;
 268 }
 269
 270 static inline int next_snapshot_time_is_valid(void)
 271 {
 272         return next_snapshot_time != 0;
 273 }
 274
 275 static int next_snapshot_is_due(void)
 276 {
 277         int64_t now = get_current_time();
 278
 279         if (!next_snapshot_time_is_valid())
 280                 next_snapshot_time = compute_next_snapshot_time();
 281         if (next_snapshot_time <= now) {
 282                 DSS_DEBUG_LOG("next snapshot: now\n");
 283                 return 1;
 284         }
 285         DSS_DEBUG_LOG("next snapshot due in %" PRId64 " seconds\n",
 286                 next_snapshot_time - now);
 287         return 0;
 288 }
 289
 290 static int pre_create_hook(void)
 291 {
 292         int ret, fds[3] = {0, 0, 0};
 293
 294         assert(snapshot_creation_status == HS_READY);
 295         /* make sure that the next snapshot time will be recomputed */
 296         invalidate_next_snapshot_time();
 297         DSS_DEBUG_LOG("executing %s\n", conf.pre_create_hook_arg);
 298         ret = dss_exec_cmdline_pid(&create_pid,
 299                 conf.pre_create_hook_arg, fds);
 300         if (ret < 0)
 301                 return ret;
 302         snapshot_creation_status = HS_PRE_RUNNING;
 303         return ret;
 304 }
 305
 306 static int pre_remove_hook(struct snapshot *s, const char *why)
 307 {
 308         int ret, fds[3] = {0, 0, 0};
 309         char *cmd;
 310
 311         if (!s)
 312                 return 0;
 313         DSS_DEBUG_LOG("%s snapshot %s\n", why, s->name);
 314         assert(snapshot_removal_status == HS_READY);
 315         assert(remove_pid == 0);
 316         assert(!snapshot_currently_being_removed);
 317
 318         snapshot_currently_being_removed = dss_malloc(sizeof(struct snapshot));
 319         *snapshot_currently_being_removed = *s;
 320         snapshot_currently_being_removed->name = dss_strdup(s->name);
 321
 322         cmd = make_message("%s %s/%s", conf.pre_remove_hook_arg,
 323                 conf.dest_dir_arg, s->name);
 324         DSS_DEBUG_LOG("executing %s\n", cmd);
 325         ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
 326         free(cmd);
 327         if (ret < 0)
 328                 return ret;
 329         snapshot_removal_status = HS_PRE_RUNNING;
 330         return ret;
 331 }
 332
 333 static int exec_rm(void)
 334 {
 335         struct snapshot *s = snapshot_currently_being_removed;
 336         int fds[3] = {0, 0, 0};
 337         char *new_name = being_deleted_name(s);
 338         char *argv[] = {"rm", "-rf", new_name, NULL};
 339         int ret;
 340
 341         assert(snapshot_removal_status == HS_PRE_SUCCESS);
 342         assert(remove_pid == 0);
 343
 344         DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
 345         ret = dss_rename(s->name, new_name);
 346         if (ret < 0)
 347                 goto out;
 348         ret = dss_exec(&remove_pid, argv[0], argv, fds);
 349         if (ret < 0)
 350                 goto out;
 351         snapshot_removal_status = HS_RUNNING;
 352 out:
 353         free(new_name);
 354         return ret;
 355 }
 356
 357 static int snapshot_is_being_created(struct snapshot *s)
 358 {
 359         return s->creation_time == current_snapshot_creation_time;
 360 }
 361
 362 static struct snapshot *find_orphaned_snapshot(struct snapshot_list *sl)
 363 {
 364         struct snapshot *s;
 365         int i;
 366
 367         DSS_DEBUG_LOG("looking for orphaned snapshots\n");
 368         FOR_EACH_SNAPSHOT(s, i, sl) {
 369                 if (snapshot_is_being_created(s))
 370                         continue;
 371                 /*
 372                  * We know that no rm is currently running, so if s is marked
 373                  * as being deleted, a previously started rm must have failed.
 374                  */
 375                 if (s->flags & SS_BEING_DELETED)
 376                         return s;
 377
 378                 if (s->flags & SS_COMPLETE) /* good snapshot */
 379                         continue;
 380                 /*
 381                  * This snapshot is incomplete and it is not the snapshot
 382                  * currently being created. However, we must not remove it if
 383                  * rsync is about to be restarted. As only the newest snapshot
 384                  * can be restarted, this snapshot is orphaned if it is not the
 385                  * newest snapshot or if we are not about to restart rsync.
 386                  */
 387                 if (get_newest_snapshot(sl) != s)
 388                         return s;
 389                 if (snapshot_creation_status != HS_NEEDS_RESTART)
 390                         return s;
 391         }
 392         /* no orphaned snapshots */
 393         return NULL;
 394 }
 395
 396 static int is_reference_snapshot(struct snapshot *s)
 397 {
 398         if (!name_of_reference_snapshot)
 399                 return 0;
 400         return strcmp(s->name, name_of_reference_snapshot)? 0 : 1;
 401 }
 402
 403 /*
 404  * return: 0: no redundant snapshots, 1: rm process started, negative: error
 405  */
 406 static struct snapshot *find_redundant_snapshot(struct snapshot_list *sl)
 407 {
 408         int i, interval;
 409         struct snapshot *s;
 410         unsigned missing = 0;
 411
 412         DSS_DEBUG_LOG("looking for intervals containing too many snapshots\n");
 413         for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
 414                 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
 415                 unsigned num = sl->interval_count[interval];
 416                 struct snapshot *victim = NULL, *prev = NULL;
 417                 int64_t score = LONG_MAX;
 418
 419                 if (keep >= num)
 420                         missing += keep - num;
 421 //              DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
 422 //                      interval, keep, num, missing);
 423                 if (keep + missing >= num)
 424                         continue;
 425                 /* redundant snapshot in this interval, pick snapshot with lowest score */
 426                 FOR_EACH_SNAPSHOT(s, i, sl) {
 427                         int64_t this_score;
 428
 429                         if (snapshot_is_being_created(s))
 430                                 continue;
 431                         if (is_reference_snapshot(s))
 432                                 continue;
 433                         //DSS_DEBUG_LOG("checking %s\n", s->name);
 434                         if (s->interval > interval) {
 435                                 prev = s;
 436                                 continue;
 437                         }
 438                         if (s->interval < interval)
 439                                 break;
 440                         if (!victim) {
 441                                 victim = s;
 442                                 prev = s;
 443                                 continue;
 444                         }
 445                         assert(prev);
 446                         /* check if s is a better victim */
 447                         this_score = s->creation_time - prev->creation_time;
 448                         assert(this_score >= 0);
 449                         //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
 450                         if (this_score < score) {
 451                                 score = this_score;
 452                                 victim = s;
 453                         }
 454                         prev = s;
 455                 }
 456                 assert(victim);
 457                 return victim;
 458         }
 459         return NULL;
 460 }
 461
 462 static struct snapshot *find_outdated_snapshot(struct snapshot_list *sl)
 463 {
 464         int i;
 465         struct snapshot *s;
 466
 467         DSS_DEBUG_LOG("looking for snapshots belonging to intervals >= %d\n",
 468                 conf.num_intervals_arg);
 469         FOR_EACH_SNAPSHOT(s, i, sl) {
 470                 if (snapshot_is_being_created(s))
 471                         continue;
 472                 if (is_reference_snapshot(s))
 473                         continue;
 474                 if (s->interval < conf.num_intervals_arg)
 475                         continue;
 476                 return s;
 477         }
 478         return NULL;
 479 }
 480
 481 struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
 482 {
 483         int i;
 484         struct snapshot *s;
 485         FOR_EACH_SNAPSHOT(s, i, sl) {
 486                 if (snapshot_is_being_created(s))
 487                         continue;
 488                 if (is_reference_snapshot(s))
 489                         continue;
 490                 DSS_INFO_LOG("oldest removable snapshot: %s\n", s->name);
 491                 return s;
 492         }
 493         return NULL;
 494 }
 495
 496 static int rename_incomplete_snapshot(int64_t start)
 497 {
 498         char *old_name;
 499         int ret;
 500
 501         free(path_to_last_complete_snapshot);
 502         ret = complete_name(start, get_current_time(),
 503                 &path_to_last_complete_snapshot);
 504         if (ret < 0)
 505                 return ret;
 506         old_name = incomplete_name(start);
 507         ret = dss_rename(old_name, path_to_last_complete_snapshot);
 508         if (ret >= 0)
 509                 DSS_NOTICE_LOG("%s -> %s\n", old_name,
 510                         path_to_last_complete_snapshot);
 511         free(old_name);
 512         return ret;
 513 }
 514
 515 static int try_to_free_disk_space(void)
 516 {
 517         int ret;
 518         struct snapshot_list sl;
 519         struct snapshot *victim;
 520         struct timeval now;
 521         const char *why;
 522         int low_disk_space;
 523
 524         ret = disk_space_low(NULL);
 525         if (ret < 0)
 526                 return ret;
 527         low_disk_space = ret;
 528         gettimeofday(&now, NULL);
 529         if (tv_diff(&next_removal_check, &now, NULL) > 0)
 530                 return 0;
 531         if (!low_disk_space) {
 532                 if (conf.keep_redundant_given)
 533                         return 0;
 534                 if (snapshot_creation_status != HS_READY)
 535                         return 0;
 536                 if (next_snapshot_is_due())
 537                         return 0;
 538         }
 539         dss_get_snapshot_list(&sl);
 540         ret = 0;
 541         if (!low_disk_space && sl.num_snapshots <= 1)
 542                 goto out;
 543         why = "outdated";
 544         victim = find_outdated_snapshot(&sl);
 545         if (victim)
 546                 goto remove;
 547         why = "redundant";
 548         victim = find_redundant_snapshot(&sl);
 549         if (victim)
 550                 goto remove;
 551         /* try harder only if disk space is low */
 552         if (!low_disk_space)
 553                 goto out;
 554         why = "orphaned";
 555         victim = find_orphaned_snapshot(&sl);
 556         if (victim)
 557                 goto remove;
 558         DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
 559         victim = find_oldest_removable_snapshot(&sl);
 560         if (victim)
 561                 goto remove;
 562         DSS_CRIT_LOG("uhuhu: disk space low and nothing to remove\n");
 563         ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
 564         goto out;
 565 remove:
 566         ret = pre_remove_hook(victim, why);
 567 out:
 568         free_snapshot_list(&sl);
 569         return ret;
 570 }
 571
 572 static int post_create_hook(void)
 573 {
 574         int ret, fds[3] = {0, 0, 0};
 575         char *cmd;
 576
 577         cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
 578                 conf.dest_dir_arg, path_to_last_complete_snapshot);
 579         DSS_NOTICE_LOG("executing %s\n", cmd);
 580         ret = dss_exec_cmdline_pid(&create_pid, cmd, fds);
 581         free(cmd);
 582         if (ret < 0)
 583                 return ret;
 584         snapshot_creation_status = HS_POST_RUNNING;
 585         return ret;
 586 }
 587
 588 static int post_remove_hook(void)
 589 {
 590         int ret, fds[3] = {0, 0, 0};
 591         char *cmd;
 592         struct snapshot *s = snapshot_currently_being_removed;
 593
 594         assert(s);
 595
 596         cmd = make_message("%s %s/%s", conf.post_remove_hook_arg,
 597                 conf.dest_dir_arg, s->name);
 598         DSS_NOTICE_LOG("executing %s\n", cmd);
 599         ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
 600         free(cmd);
 601         if (ret < 0)
 602                 return ret;
 603         snapshot_removal_status = HS_POST_RUNNING;
 604         return ret;
 605 }
 606
 607 static void dss_kill(pid_t pid, int sig, const char *msg)
 608 {
 609         const char *signame, *process_name;
 610
 611         if (pid == 0)
 612                 return;
 613         switch (sig) {
 614         case SIGTERM: signame = "TERM"; break;
 615         case SIGSTOP: signame = "STOP"; break;
 616         case SIGCONT: signame = "CONT"; break;
 617         default: signame = "????";
 618         }
 619
 620         if (pid == create_pid)
 621                 process_name = "create";
 622         else if (pid == remove_pid)
 623                 process_name = "remove";
 624         else process_name = "??????";
 625
 626         if (msg)
 627                 DSS_INFO_LOG("%s\n", msg);
 628         DSS_DEBUG_LOG("sending signal %d (%s) to pid %d (%s process)\n",
 629                 sig, signame, (int)pid, process_name);
 630         if (kill(pid, sig) >= 0)
 631                 return;
 632         DSS_INFO_LOG("failed to send signal %d (%s) to pid %d (%s process)\n",
 633                 sig, signame, (int)pid, process_name);
 634 }
 635
 636 static void stop_create_process(void)
 637 {
 638         if (create_process_stopped)
 639                 return;
 640         dss_kill(create_pid, SIGSTOP, "suspending create process");
 641         create_process_stopped = 1;
 642 }
 643
 644 static void restart_create_process(void)
 645 {
 646         if (!create_process_stopped)
 647                 return;
 648         dss_kill(create_pid, SIGCONT, "resuming create process");
 649         create_process_stopped = 0;
 650 }
 651
 652 /**
 653  * Print a log message about the exit status of a child.
 654  */
 655 static void log_termination_msg(pid_t pid, int status)
 656 {
 657         if (WIFEXITED(status))
 658                 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
 659                         WEXITSTATUS(status));
 660         else if (WIFSIGNALED(status))
 661                 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
 662                         WTERMSIG(status));
 663         else
 664                 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
 665 }
 666
 667 static int wait_for_process(pid_t pid, int *status)
 668 {
 669         int ret;
 670
 671         DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
 672         for (;;) {
 673                 fd_set rfds;
 674
 675                 FD_ZERO(&rfds);
 676                 FD_SET(signal_pipe, &rfds);
 677                 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
 678                 if (ret < 0)
 679                         break;
 680                 ret = next_signal();
 681                 if (!ret)
 682                         continue;
 683                 if (ret == SIGCHLD) {
 684                         ret = waitpid(pid, status, 0);
 685                         if (ret >= 0)
 686                                 break;
 687                         if (errno != EINTR) { /* error */
 688                                 ret = -ERRNO_TO_DSS_ERROR(errno);
 689                                 break;
 690                         }
 691                 }
 692                 /* SIGINT or SIGTERM */
 693                 dss_kill(pid, SIGTERM, "killing child process");
 694         }
 695         if (ret < 0)
 696                 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
 697         else
 698                 log_termination_msg(pid, *status);
 699         return ret;
 700 }
 701
 702 static void handle_pre_remove_exit(int status)
 703 {
 704         if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 705                 snapshot_removal_status = HS_READY;
 706                 gettimeofday(&next_removal_check, NULL);
 707                 next_removal_check.tv_sec += 60;
 708                 return;
 709         }
 710         snapshot_removal_status = HS_PRE_SUCCESS;
 711 }
 712
 713 static int handle_rm_exit(int status)
 714 {
 715         if (!WIFEXITED(status)) {
 716                 snapshot_removal_status = HS_READY;
 717                 return -E_INVOLUNTARY_EXIT;
 718         }
 719         if (WEXITSTATUS(status)) {
 720                 snapshot_removal_status = HS_READY;
 721                 return -E_BAD_EXIT_CODE;
 722         }
 723         snapshot_removal_status = HS_SUCCESS;
 724         return 1;
 725 }
 726
 727 static void handle_post_remove_exit(void)
 728 {
 729         snapshot_removal_status = HS_READY;
 730 }
 731
 732 static int handle_remove_exit(int status)
 733 {
 734         int ret;
 735         struct snapshot *s = snapshot_currently_being_removed;
 736
 737         assert(s);
 738         switch (snapshot_removal_status) {
 739         case HS_PRE_RUNNING:
 740                 handle_pre_remove_exit(status);
 741                 ret = 1;
 742                 break;
 743         case HS_RUNNING:
 744                 ret = handle_rm_exit(status);
 745                 break;
 746         case HS_POST_RUNNING:
 747                 handle_post_remove_exit();
 748                 ret = 1;
 749                 break;
 750         default:
 751                 ret = -E_BUG;
 752         }
 753         if (snapshot_removal_status == HS_READY) {
 754                 free(s->name);
 755                 free(s);
 756                 snapshot_currently_being_removed = NULL;
 757         }
 758         remove_pid = 0;
 759         return ret;
 760 }
 761
 762 static int wait_for_remove_process(void)
 763 {
 764         int status, ret;
 765
 766         assert(remove_pid);
 767         assert(
 768                 snapshot_removal_status == HS_PRE_RUNNING ||
 769                 snapshot_removal_status == HS_RUNNING ||
 770                 snapshot_removal_status == HS_POST_RUNNING
 771         );
 772         ret = wait_for_process(remove_pid, &status);
 773         if (ret < 0)
 774                 return ret;
 775         return handle_remove_exit(status);
 776 }
 777
 778 static int handle_rsync_exit(int status)
 779 {
 780         int es, ret;
 781
 782         if (!WIFEXITED(status)) {
 783                 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)create_pid);
 784                 ret = -E_INVOLUNTARY_EXIT;
 785                 snapshot_creation_status = HS_READY;
 786                 goto out;
 787         }
 788         es = WEXITSTATUS(status);
 789         /*
 790          * Restart rsync on non-fatal errors:
 791          * 12: Error in rsync protocol data stream
 792          * 13: Errors with program diagnostics
 793          */
 794         if (es == 12 || es == 13) {
 795                 DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
 796                         (int)create_pid, es);
 797                 snapshot_creation_status = HS_NEEDS_RESTART;
 798                 next_snapshot_time = get_current_time() + 60;
 799                 ret = 1;
 800                 goto out;
 801         }
 802         if (es != 0 && es != 23 && es != 24) {
 803                 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)create_pid, es);
 804                 ret = -E_BAD_EXIT_CODE;
 805                 snapshot_creation_status = HS_READY;
 806                 goto out;
 807         }
 808         ret = rename_incomplete_snapshot(current_snapshot_creation_time);
 809         if (ret < 0)
 810                 goto out;
 811         snapshot_creation_status = HS_SUCCESS;
 812         free(name_of_reference_snapshot);
 813         name_of_reference_snapshot = NULL;
 814 out:
 815         create_process_stopped = 0;
 816         return ret;
 817 }
 818
 819 static int handle_pre_create_hook_exit(int status)
 820 {
 821         int es, ret;
 822         static int warn_count;
 823
 824         if (!WIFEXITED(status)) {
 825                 snapshot_creation_status = HS_READY;
 826                 ret = -E_INVOLUNTARY_EXIT;
 827                 goto out;
 828         }
 829         es = WEXITSTATUS(status);
 830         if (es) {
 831                 if (!warn_count--) {
 832                         DSS_NOTICE_LOG("pre_create_hook %s returned %d\n",
 833                                 conf.pre_create_hook_arg, es);
 834                         DSS_NOTICE_LOG("deferring snapshot creation...\n");
 835                         warn_count = 60; /* warn only once per hour */
 836                 }
 837                 next_snapshot_time = get_current_time() + 60;
 838                 snapshot_creation_status = HS_READY;
 839                 ret = 0;
 840                 goto out;
 841         }
 842         warn_count = 0;
 843         snapshot_creation_status = HS_PRE_SUCCESS;
 844         ret = 1;
 845 out:
 846         return ret;
 847 }
 848
 849 static int handle_sigchld(void)
 850 {
 851         pid_t pid;
 852         int status, ret = reap_child(&pid, &status);
 853
 854         if (ret <= 0)
 855                 return ret;
 856
 857         if (pid == create_pid) {
 858                 switch (snapshot_creation_status) {
 859                 case HS_PRE_RUNNING:
 860                         ret = handle_pre_create_hook_exit(status);
 861                         break;
 862                 case HS_RUNNING:
 863                         ret = handle_rsync_exit(status);
 864                         break;
 865                 case HS_POST_RUNNING:
 866                         snapshot_creation_status = HS_READY;
 867                         ret = 1;
 868                         break;
 869                 default:
 870                         DSS_EMERG_LOG("BUG: create can't die in status %d\n",
 871                                 snapshot_creation_status);
 872                         return -E_BUG;
 873                 }
 874                 create_pid = 0;
 875                 return ret;
 876         }
 877         if (pid == remove_pid) {
 878                 ret = handle_remove_exit(status);
 879                 if (ret < 0)
 880                         return ret;
 881                 return ret;
 882         }
 883         DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
 884         return -E_BUG;
 885 }
 886
 887 static int check_config(void)
 888 {
 889         if (conf.unit_interval_arg <= 0) {
 890                 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
 891                 return -E_INVALID_NUMBER;
 892         }
 893         DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
 894         if (conf.num_intervals_arg <= 0) {
 895                 DSS_ERROR_LOG("bad number of intervals  %i\n", conf.num_intervals_arg);
 896                 return -E_INVALID_NUMBER;
 897         }
 898         DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
 899         return 1;
 900 }
 901
 902 /*
 903  * Returns < 0 on errors, 0 if no config file is given and > 0 if the config
 904  * file was read successfully.
 905  */
 906 static int parse_config_file(int override)
 907 {
 908         int ret, config_file_exists;
 909         char *config_file;
 910         struct stat statbuf;
 911         char *old_logfile_arg = NULL;
 912         int old_daemon_given = 0;
 913
 914         if (conf.config_file_given)
 915                 config_file = dss_strdup(conf.config_file_arg);
 916         else {
 917                 char *home = get_homedir();
 918                 config_file = make_message("%s/.dssrc", home);
 919                 free(home);
 920         }
 921         if (override) { /* SIGHUP */
 922                 if (conf.logfile_given)
 923                         old_logfile_arg = dss_strdup(conf.logfile_arg);
 924                 old_daemon_given = conf.daemon_given;
 925         }
 926
 927         config_file_exists = !stat(config_file, &statbuf);
 928         if (!config_file_exists && conf.config_file_given) {
 929                 ret = -ERRNO_TO_DSS_ERROR(errno);
 930                 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
 931                 goto out;
 932         }
 933         if (config_file_exists) {
 934                 struct cmdline_parser_params params = {
 935                         .override = override,
 936                         .initialize = 0,
 937                         .check_required = 1,
 938                         .check_ambiguity = 0,
 939                         .print_errors = 1
 940                 };
 941                 if (override) { /* invalidate all rsync options */
 942                         int i;
 943
 944                         for (i = 0; i < conf.rsync_option_given; i++) {
 945                                 free(conf.rsync_option_arg[i]);
 946                                 conf.rsync_option_arg[i] = NULL;
 947                         }
 948                         conf.rsync_option_given = 0;
 949                 }
 950                 cmdline_parser_config_file(config_file, &conf, &params);
 951         }
 952         ret = check_config();
 953         if (ret < 0)
 954                 goto out;
 955         if (override) {
 956                 /* don't change daemon mode on SIGHUP */
 957                 conf.daemon_given = old_daemon_given;
 958                 close_log(logfile);
 959                 logfile = NULL;
 960                 if (conf.logfile_given)
 961                         free(old_logfile_arg);
 962                 else if (conf.daemon_given) { /* re-use old logfile */
 963                         conf.logfile_arg = old_logfile_arg;
 964                         conf.logfile_given = 1;
 965                 }
 966         }
 967         if (conf.logfile_given && conf.run_given && conf.daemon_given) {
 968                 logfile = open_log(conf.logfile_arg);
 969                 log_welcome(conf.loglevel_arg);
 970         }
 971         DSS_DEBUG_LOG("loglevel: %d\n", conf.loglevel_arg);
 972         ret = config_file_exists;
 973 out:
 974         free(config_file);
 975         if (ret < 0)
 976                 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
 977         return ret;
 978 }
 979
 980 static int change_to_dest_dir(void)
 981 {
 982         DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
 983         return dss_chdir(conf.dest_dir_arg);
 984 }
 985
 986 static int handle_sighup(void)
 987 {
 988         int ret;
 989
 990         DSS_NOTICE_LOG("SIGHUP, re-reading config\n");
 991         dump_dss_config("old");
 992         ret = parse_config_file(1);
 993         if (ret < 0)
 994                 return ret;
 995         dump_dss_config("reloaded");
 996         invalidate_next_snapshot_time();
 997         return change_to_dest_dir();
 998 }
 999
1000 static int handle_signal(void)
1001 {
1002         int sig, ret = next_signal();
1003
1004         if (ret <= 0)
1005                 goto out;
1006         sig = ret;
1007         switch (sig) {
1008         case SIGINT:
1009         case SIGTERM:
1010                 restart_create_process();
1011                 dss_kill(create_pid, SIGTERM, NULL);
1012                 dss_kill(remove_pid, SIGTERM, NULL);
1013                 ret = -E_SIGNAL;
1014                 break;
1015         case SIGHUP:
1016                 ret = handle_sighup();
1017                 break;
1018         case SIGCHLD:
1019                 ret = handle_sigchld();
1020                 break;
1021         }
1022 out:
1023         if (ret < 0)
1024                 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
1025         return ret;
1026 }
1027
1028 /*
1029  * We can not use rsync locally if the local user is different from the remote
1030  * user or if the src dir is not on the local host (or both).
1031  */
1032 static int use_rsync_locally(char *logname)
1033 {
1034         char *h = conf.remote_host_arg;
1035
1036         if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
1037                 return 0;
1038         if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
1039                 return 0;
1040         return 1;
1041 }
1042
1043 static int rename_resume_snap(int64_t creation_time)
1044 {
1045         struct snapshot_list sl = {.num_snapshots = 0};
1046         struct snapshot *s;
1047         char *new_name = incomplete_name(creation_time);
1048         int ret;
1049
1050         ret = 0;
1051         if (conf.no_resume_given)
1052                 goto out;
1053         dss_get_snapshot_list(&sl);
1054         s = get_newest_snapshot(&sl);
1055         if (!s)
1056                 goto out;
1057         if ((s->flags & SS_COMPLETE) != 0) /* complete */
1058                 goto out;
1059         DSS_INFO_LOG("resuming: reusing %s as destination dir\n", s->name);
1060         ret = dss_rename(s->name, new_name);
1061 out:
1062         if (ret >= 0)
1063                 DSS_NOTICE_LOG("creating new snapshot %s\n", new_name);
1064         free(new_name);
1065         free_snapshot_list(&sl);
1066         return ret;
1067 }
1068
1069 static void create_rsync_argv(char ***argv, int64_t *num)
1070 {
1071         char *logname;
1072         int i = 0, j;
1073         struct snapshot_list sl;
1074
1075         dss_get_snapshot_list(&sl);
1076         assert(!name_of_reference_snapshot);
1077         name_of_reference_snapshot = name_of_newest_complete_snapshot(&sl);
1078         free_snapshot_list(&sl);
1079
1080         *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
1081         (*argv)[i++] = dss_strdup("rsync");
1082         (*argv)[i++] = dss_strdup("-aq");
1083         (*argv)[i++] = dss_strdup("--delete");
1084         for (j = 0; j < conf.rsync_option_given; j++)
1085                 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
1086         if (name_of_reference_snapshot) {
1087                 DSS_INFO_LOG("using %s as reference\n", name_of_reference_snapshot);
1088                 (*argv)[i++] = make_message("--link-dest=../%s",
1089                         name_of_reference_snapshot);
1090         } else
1091                 DSS_INFO_LOG("no suitable reference snapshot found\n");
1092         logname = dss_logname();
1093         if (use_rsync_locally(logname))
1094                 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
1095         else
1096                 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
1097                         conf.remote_user_arg : logname,
1098                         conf.remote_host_arg, conf.source_dir_arg);
1099         free(logname);
1100         *num = get_current_time();
1101         (*argv)[i++] = incomplete_name(*num);
1102         (*argv)[i++] = NULL;
1103         for (j = 0; j < i; j++)
1104                 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
1105 }
1106
1107 static void free_rsync_argv(char **argv)
1108 {
1109         int i;
1110
1111         if (!argv)
1112                 return;
1113         for (i = 0; argv[i]; i++)
1114                 free(argv[i]);
1115         free(argv);
1116 }
1117
1118 static int create_snapshot(char **argv)
1119 {
1120         int ret, fds[3] = {0, 0, 0};
1121
1122         ret = rename_resume_snap(current_snapshot_creation_time);
1123         if (ret < 0)
1124                 return ret;
1125         ret = dss_exec(&create_pid, argv[0], argv, fds);
1126         if (ret < 0)
1127                 return ret;
1128         snapshot_creation_status = HS_RUNNING;
1129         return ret;
1130 }
1131
1132 static int select_loop(void)
1133 {
1134         int ret;
1135         /* check every 60 seconds for free disk space */
1136         struct timeval tv;
1137         char **rsync_argv = NULL;
1138
1139         for (;;) {
1140                 fd_set rfds;
1141                 struct timeval *tvp;
1142
1143                 if (remove_pid)
1144                         tvp = NULL; /* sleep until rm hook/process dies */
1145                 else { /* sleep one minute */
1146                         tv.tv_sec = 60;
1147                         tv.tv_usec = 0;
1148                         tvp = &tv;
1149                 }
1150                 FD_ZERO(&rfds);
1151                 FD_SET(signal_pipe, &rfds);
1152                 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
1153                 if (ret < 0)
1154                         goto out;
1155                 if (FD_ISSET(signal_pipe, &rfds)) {
1156                         ret = handle_signal();
1157                         if (ret < 0)
1158                                 goto out;
1159                 }
1160                 if (remove_pid)
1161                         continue;
1162                 if (snapshot_removal_status == HS_PRE_SUCCESS) {
1163                         ret = exec_rm();
1164                         if (ret < 0)
1165                                 goto out;
1166                         continue;
1167                 }
1168                 if (snapshot_removal_status == HS_SUCCESS) {
1169                         ret = post_remove_hook();
1170                         if (ret < 0)
1171                                 goto out;
1172                         continue;
1173                 }
1174                 ret = try_to_free_disk_space();
1175                 if (ret < 0)
1176                         goto out;
1177                 if (snapshot_removal_status != HS_READY) {
1178                         stop_create_process();
1179                         continue;
1180                 }
1181                 restart_create_process();
1182                 switch (snapshot_creation_status) {
1183                 case HS_READY:
1184                         if (!next_snapshot_is_due())
1185                                 continue;
1186                         ret = pre_create_hook();
1187                         if (ret < 0)
1188                                 goto out;
1189                         continue;
1190                 case HS_PRE_RUNNING:
1191                 case HS_RUNNING:
1192                 case HS_POST_RUNNING:
1193                         continue;
1194                 case HS_PRE_SUCCESS:
1195                         if (!name_of_reference_snapshot) {
1196                                 free_rsync_argv(rsync_argv);
1197                                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1198                         }
1199                         ret = create_snapshot(rsync_argv);
1200                         if (ret < 0)
1201                                 goto out;
1202                         continue;
1203                 case HS_NEEDS_RESTART:
1204                         if (!next_snapshot_is_due())
1205                                 continue;
1206                         ret = create_snapshot(rsync_argv);
1207                         if (ret < 0)
1208                                 goto out;
1209                         continue;
1210                 case HS_SUCCESS:
1211                         ret = post_create_hook();
1212                         if (ret < 0)
1213                                 goto out;
1214                         continue;
1215                 }
1216         }
1217 out:
1218         return ret;
1219 }
1220
1221 static void exit_hook(int exit_code)
1222 {
1223         int fds[3] = {0, 0, 0};
1224         char *argv[] = {conf.exit_hook_arg, dss_strerror(-exit_code), NULL};
1225         pid_t pid;
1226
1227         DSS_NOTICE_LOG("executing %s %s\n", argv[0], argv[1]);
1228         dss_exec(&pid, conf.exit_hook_arg, argv, fds);
1229 }
1230
1231 static int com_run(void)
1232 {
1233         int ret;
1234
1235         if (conf.dry_run_given) {
1236                 DSS_ERROR_LOG("dry_run not supported by this command\n");
1237                 return -E_SYNTAX;
1238         }
1239         ret = install_sighandler(SIGHUP);
1240         if (ret < 0)
1241                 return ret;
1242         ret = select_loop();
1243         if (ret >= 0) /* impossible */
1244                 ret = -E_BUG;
1245         exit_hook(ret);
1246         return ret;
1247 }
1248
1249 static int com_prune(void)
1250 {
1251         int ret;
1252         struct snapshot_list sl;
1253         struct snapshot *victim;
1254         struct disk_space ds;
1255         const char *why;
1256
1257         ret = get_disk_space(".", &ds);
1258         if (ret < 0)
1259                 return ret;
1260         log_disk_space(&ds);
1261         dss_get_snapshot_list(&sl);
1262         why = "outdated";
1263         victim = find_outdated_snapshot(&sl);
1264         if (victim)
1265                 goto rm;
1266         why = "redundant";
1267         victim = find_redundant_snapshot(&sl);
1268         if (victim)
1269                 goto rm;
1270         ret = 0;
1271         goto out;
1272 rm:
1273         if (conf.dry_run_given) {
1274                 dss_msg("%s snapshot %s (interval = %i)\n",
1275                         why, victim->name, victim->interval);
1276                 ret = 0;
1277                 goto out;
1278         }
1279         ret = pre_remove_hook(victim, why);
1280         if (ret < 0)
1281                 goto out;
1282         if (snapshot_removal_status == HS_PRE_RUNNING) {
1283                 ret = wait_for_remove_process();
1284                 if (ret < 0)
1285                         goto out;
1286                 if (snapshot_removal_status != HS_PRE_SUCCESS)
1287                         goto out;
1288         }
1289         ret = exec_rm();
1290         if (ret < 0)
1291                 goto out;
1292         ret = wait_for_remove_process();
1293         if (ret < 0)
1294                 goto out;
1295         if (snapshot_removal_status != HS_SUCCESS)
1296                 goto out;
1297         ret = post_remove_hook();
1298         if (ret < 0)
1299                 goto out;
1300         if (snapshot_removal_status != HS_POST_RUNNING)
1301                 goto out;
1302         ret = wait_for_remove_process();
1303         if (ret < 0)
1304                 goto out;
1305         ret = 1;
1306 out:
1307         free_snapshot_list(&sl);
1308         return ret;
1309 }
1310
1311 static int com_create(void)
1312 {
1313         int ret, status;
1314         char **rsync_argv;
1315
1316         if (conf.dry_run_given) {
1317                 int i;
1318                 char *msg = NULL;
1319                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1320                 for (i = 0; rsync_argv[i]; i++) {
1321                         char *tmp = msg;
1322                         msg = make_message("%s%s%s", tmp? tmp : "",
1323                                 tmp? " " : "", rsync_argv[i]);
1324                         free(tmp);
1325                 }
1326                 free_rsync_argv(rsync_argv);
1327                 dss_msg("%s\n", msg);
1328                 free(msg);
1329                 return 1;
1330         }
1331         ret = pre_create_hook();
1332         if (ret < 0)
1333                 return ret;
1334         if (create_pid) {
1335                 ret = wait_for_process(create_pid, &status);
1336                 if (ret < 0)
1337                         return ret;
1338                 ret = handle_pre_create_hook_exit(status);
1339                 if (ret <= 0) /* error, or pre-create failed */
1340                         return ret;
1341         }
1342         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1343         ret = create_snapshot(rsync_argv);
1344         if (ret < 0)
1345                 goto out;
1346         ret = wait_for_process(create_pid, &status);
1347         if (ret < 0)
1348                 goto out;
1349         ret = handle_rsync_exit(status);
1350         if (ret < 0)
1351                 goto out;
1352         post_create_hook();
1353         if (create_pid)
1354                 ret = wait_for_process(create_pid, &status);
1355 out:
1356         free_rsync_argv(rsync_argv);
1357         return ret;
1358 }
1359
1360 static int com_ls(void)
1361 {
1362         int i;
1363         struct snapshot_list sl;
1364         struct snapshot *s;
1365
1366         dss_get_snapshot_list(&sl);
1367         FOR_EACH_SNAPSHOT(s, i, &sl) {
1368                 int64_t d = 0;
1369                 if (s->flags & SS_COMPLETE)
1370                         d = (s->completion_time - s->creation_time) / 60;
1371                 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1372         };
1373         free_snapshot_list(&sl);
1374         return 1;
1375 }
1376
1377 static int setup_signal_handling(void)
1378 {
1379         int ret;
1380
1381         DSS_INFO_LOG("setting up signal handlers\n");
1382         signal_pipe = signal_init(); /* always successful */
1383         ret = install_sighandler(SIGINT);
1384         if (ret < 0)
1385                 return ret;
1386         ret = install_sighandler(SIGTERM);
1387         if (ret < 0)
1388                 return ret;
1389         return install_sighandler(SIGCHLD);
1390 }
1391
1392 /**
1393  * The main function of dss.
1394  *
1395  * \param argc Usual argument count.
1396  * \param argv Usual argument vector.
1397  */
1398 int main(int argc, char **argv)
1399 {
1400         int ret;
1401         struct cmdline_parser_params params = {
1402                 .override = 0,
1403                 .initialize = 1,
1404                 .check_required = 0,
1405                 .check_ambiguity = 0,
1406                 .print_errors = 1
1407         };
1408
1409         cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1410         ret = parse_config_file(0);
1411         if (ret < 0)
1412                 goto out;
1413         if (ret == 0) { /* no config file given */
1414                 /*
1415                  * Parse the command line options again, but this time check
1416                  * that all required options are given.
1417                  */
1418                 params = (struct cmdline_parser_params) {
1419                         .override = 1,
1420                         .initialize = 1,
1421                         .check_required = 1,
1422                         .check_ambiguity = 1,
1423                         .print_errors = 1
1424                 };
1425                 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1426         }
1427         if (conf.daemon_given)
1428                 daemon_init();
1429         ret = change_to_dest_dir();
1430         if (ret < 0)
1431                 goto out;
1432         dump_dss_config("startup");
1433         ret = setup_signal_handling();
1434         if (ret < 0)
1435                 goto out;
1436         ret = call_command_handler();
1437 out:
1438         if (ret < 0)
1439                 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1440         exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1441 }