dss.c

   1 #include <string.h>
   2 #include <stdlib.h>
   3 #include <stdarg.h>
   4 #include <assert.h>
   5 #include <errno.h>
   6 #include <sys/types.h>
   7 #include <signal.h>
   8 #include <ctype.h>
   9 #include <sys/stat.h>
  10 #include <unistd.h>
  11 #include <inttypes.h>
  12 #include <sys/time.h>
  13 #include <time.h>
  14 #include <sys/wait.h>
  15 #include <fnmatch.h>
  16 #include <limits.h>
  17
  18
  19 #include "gcc-compat.h"
  20 #include "cmdline.h"
  21 #include "log.h"
  22 #include "string.h"
  23 #include "error.h"
  24 #include "fd.h"
  25 #include "exec.h"
  26 #include "daemon.h"
  27 #include "signal.h"
  28 #include "df.h"
  29 #include "time.h"
  30 #include "snap.h"
  31
  32 /** Command line and config file options. */
  33 static struct gengetopt_args_info conf;
  34 /** Non-NULL if we log to a file. */
  35 static FILE *logfile;
  36 /** The read end of the signal pipe */
  37 static int signal_pipe;
  38 /** Process id of current rsync process. */
  39 static pid_t rsync_pid;
  40 /** Whether the rsync process is currently stopped */
  41 static int rsync_stopped;
  42 /** Process id of current rm process. */
  43 static pid_t rm_pid;
  44 /** When the next snapshot is due. */
  45 static struct timeval next_snapshot_time;
  46 /** The pid of the pre-create hook. */
  47 static pid_t pre_create_hook_pid;
  48 /** The pid of the post-create hook. */
  49 static pid_t post_create_hook_pid;
  50 /** Creation time of the snapshot currently being created. */
  51 static int64_t current_snapshot_creation_time;
  52 /** Needed by the post-create hook. */
  53 static char *path_to_last_complete_snapshot;
  54 /** \sa \ref snap.h for details. */
  55 static unsigned snapshot_creation_status;
  56
  57
  58 DEFINE_DSS_ERRLIST;
  59
  60
  61 /* a litte cpp magic helps to DRY */
  62 #define COMMANDS \
  63         COMMAND(ls) \
  64         COMMAND(create) \
  65         COMMAND(prune) \
  66         COMMAND(run)
  67 #define COMMAND(x) static int com_ ##x(void);
  68 COMMANDS
  69 #undef COMMAND
  70 #define COMMAND(x) if (conf.x ##_given) return com_ ##x();
  71 static int call_command_handler(void)
  72 {
  73         COMMANDS
  74         DSS_EMERG_LOG("BUG: did not find command handler\n");
  75         exit(EXIT_FAILURE);
  76 }
  77 #undef COMMAND
  78 #undef COMMANDS
  79
  80 /**
  81  * The log function of dss.
  82  *
  83  * \param ll Loglevel.
  84  * \param fml Usual format string.
  85  *
  86  * All DSS_XXX_LOG() macros use this function.
  87  */
  88 __printf_2_3 void dss_log(int ll, const char* fmt,...)
  89 {
  90         va_list argp;
  91         FILE *outfd;
  92         struct tm *tm;
  93         time_t t1;
  94         char str[255] = "";
  95
  96         if (ll < conf.loglevel_arg)
  97                 return;
  98         outfd = logfile? logfile : stderr;
  99         time(&t1);
 100         tm = localtime(&t1);
 101         strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
 102         fprintf(outfd, "%s ", str);
 103         if (conf.loglevel_arg <= INFO)
 104                 fprintf(outfd, "%i: ", ll);
 105         va_start(argp, fmt);
 106         vfprintf(outfd, fmt, argp);
 107         va_end(argp);
 108 }
 109
 110 /**
 111  * Print a message either to stdout or to the log file.
 112  */
 113 static __printf_1_2 void dss_msg(const char* fmt,...)
 114 {
 115         FILE *outfd = conf.daemon_given? logfile : stdout;
 116         va_list argp;
 117         va_start(argp, fmt);
 118         vfprintf(outfd, fmt, argp);
 119         va_end(argp);
 120 }
 121
 122 /* TODO: Also consider number of inodes. */
 123 static int disk_space_low(void)
 124 {
 125         struct disk_space ds;
 126         int ret = get_disk_space(".", &ds);
 127
 128         if (ret < 0)
 129                 return ret;
 130         if (conf.min_free_mb_arg)
 131                 if (ds.free_mb < conf.min_free_mb_arg)
 132                         return 1;
 133         if (conf.min_free_percent_arg)
 134                 if (ds.percent_free < conf.min_free_percent_arg)
 135                         return 1;
 136         if (conf.min_free_percent_inodes_arg)
 137                 if (ds.percent_free_inodes < conf.min_free_percent_inodes_arg)
 138                         return 1;
 139         return 0;
 140 }
 141
 142 static void dss_get_snapshot_list(struct snapshot_list *sl)
 143 {
 144         get_snapshot_list(sl, conf.unit_interval_arg, conf.num_intervals_arg);
 145 }
 146
 147 static void compute_next_snapshot_time(void)
 148 {
 149         struct timeval now, unit_interval = {.tv_sec = 24 * 3600 * conf.unit_interval_arg},
 150                 tmp, diff;
 151         int64_t x = 0;
 152         unsigned wanted = desired_number_of_snapshots(0, conf.num_intervals_arg),
 153                 num_complete_snapshots = 0;
 154         int i, ret;
 155         struct snapshot *s = NULL;
 156         struct snapshot_list sl;
 157
 158         assert(snapshot_creation_status == SCS_READY);
 159         current_snapshot_creation_time = 0;
 160         dss_get_snapshot_list(&sl);
 161         FOR_EACH_SNAPSHOT(s, i, &sl) {
 162                 if (!(s->flags & SS_COMPLETE))
 163                         continue;
 164                 num_complete_snapshots++;
 165                 x += s->completion_time - s->creation_time;
 166         }
 167         assert(x >= 0);
 168         if (num_complete_snapshots)
 169                 x /= num_complete_snapshots; /* avg time to create one snapshot */
 170         x *= wanted; /* time to create all snapshots in interval 0 */
 171         tmp.tv_sec = x;
 172         tmp.tv_usec = 0;
 173         ret = tv_diff(&unit_interval, &tmp, &diff); /* total sleep time per unit interval */
 174         gettimeofday(&now, NULL);
 175         if (ret < 0 || !s)
 176                 goto min_sleep;
 177         tv_divide(wanted, &diff, &tmp); /* sleep time betweeen two snapshots */
 178         diff.tv_sec = s->completion_time;
 179         diff.tv_usec = 0;
 180         tv_add(&diff, &tmp, &next_snapshot_time);
 181         if (tv_diff(&now, &next_snapshot_time, NULL) < 0)
 182                 goto out;
 183 min_sleep:
 184         next_snapshot_time = now;
 185         next_snapshot_time.tv_sec += 60;
 186 out:
 187         free_snapshot_list(&sl);
 188 }
 189
 190
 191 static int remove_snapshot(struct snapshot *s)
 192 {
 193         int fds[3] = {0, 0, 0};
 194         assert(!rm_pid);
 195         char *new_name = being_deleted_name(s);
 196         int ret = dss_rename(s->name, new_name);
 197         char *argv[] = {"rm", "-rf", new_name, NULL};
 198
 199         if (ret < 0)
 200                 goto out;
 201         DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
 202         ret = dss_exec(&rm_pid, argv[0], argv, fds);
 203 out:
 204         free(new_name);
 205         return ret;
 206 }
 207
 208 /*
 209  * return: 0: no redundant snapshots, 1: rm process started, negative: error
 210  */
 211 static int remove_redundant_snapshot(struct snapshot_list *sl)
 212 {
 213         int ret, i, interval;
 214         struct snapshot *s;
 215         unsigned missing = 0;
 216
 217         DSS_INFO_LOG("looking for intervals containing too many snapshots\n");
 218         for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
 219                 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
 220                 unsigned num = sl->interval_count[interval];
 221                 struct snapshot *victim = NULL, *prev = NULL;
 222                 int64_t score = LONG_MAX;
 223
 224                 if (keep >= num)
 225                         missing += keep - num;
 226 //              DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
 227 //                      interval, keep, num, missing);
 228                 if (keep + missing >= num)
 229                         continue;
 230                 /* redundant snapshot in this interval, pick snapshot with lowest score */
 231                 FOR_EACH_SNAPSHOT(s, i, sl) {
 232                         int64_t this_score;
 233
 234                         //DSS_DEBUG_LOG("checking %s\n", s->name);
 235                         if (s->interval > interval) {
 236                                 prev = s;
 237                                 continue;
 238                         }
 239                         if (s->interval < interval)
 240                                 break;
 241                         if (!victim) {
 242                                 victim = s;
 243                                 prev = s;
 244                                 continue;
 245                         }
 246                         assert(prev);
 247                         /* check if s is a better victim */
 248                         this_score = s->creation_time - prev->creation_time;
 249                         assert(this_score >= 0);
 250                         //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
 251                         if (this_score < score) {
 252                                 score = this_score;
 253                                 victim = s;
 254                         }
 255                         prev = s;
 256                 }
 257                 assert(victim);
 258                 if (conf.dry_run_given) {
 259                         dss_msg("%s would be removed (interval = %i)\n",
 260                                 victim->name, victim->interval);
 261                         continue;
 262                 }
 263                 ret = remove_snapshot(victim);
 264                 return ret < 0? ret : 1;
 265         }
 266         return 0;
 267 }
 268
 269 static int remove_outdated_snapshot(struct snapshot_list *sl)
 270 {
 271         int i, ret;
 272         struct snapshot *s;
 273
 274         DSS_INFO_LOG("looking for snapshots belonging to intervals greater than %d\n",
 275                 conf.num_intervals_arg);
 276         FOR_EACH_SNAPSHOT(s, i, sl) {
 277                 if (s->interval <= conf.num_intervals_arg)
 278                         continue;
 279                 if (conf.dry_run_given) {
 280                         dss_msg("%s would be removed (interval = %i)\n",
 281                                 s->name, s->interval);
 282                         continue;
 283                 }
 284                 ret = remove_snapshot(s);
 285                 if (ret < 0)
 286                         return ret;
 287                 return 1;
 288         }
 289         return 0;
 290 }
 291
 292 static int remove_oldest_snapshot(struct snapshot_list *sl)
 293 {
 294         struct snapshot *s = get_oldest_snapshot(sl);
 295
 296         if (!s) /* no snapshot found */
 297                 return 0;
 298         DSS_INFO_LOG("oldest snapshot: %s\n", s->name);
 299         if (s->creation_time == current_snapshot_creation_time)
 300                 return 0; /* do not remove the snapshot currently being created */
 301         return remove_snapshot(s);
 302 }
 303
 304 static int rename_incomplete_snapshot(int64_t start)
 305 {
 306         char *old_name;
 307         int ret;
 308
 309         free(path_to_last_complete_snapshot);
 310         ret = complete_name(start, get_current_time(),
 311                 &path_to_last_complete_snapshot);
 312         if (ret < 0)
 313                 return ret;
 314         old_name = incomplete_name(start);
 315         ret = dss_rename(old_name, path_to_last_complete_snapshot);
 316         if (ret >= 0)
 317                 DSS_NOTICE_LOG("%s -> %s\n", old_name,
 318                         path_to_last_complete_snapshot);
 319         free(old_name);
 320         return ret;
 321 }
 322
 323 static int try_to_free_disk_space(int low_disk_space)
 324 {
 325         int ret;
 326         struct snapshot_list sl;
 327
 328         dss_get_snapshot_list(&sl);
 329         ret = remove_outdated_snapshot(&sl);
 330         if (ret) /* error, or we are removing something */
 331                 goto out;
 332         /* no outdated snapshot */
 333         ret = remove_redundant_snapshot(&sl);
 334         if (ret)
 335                 goto out;
 336         ret = 0;
 337         if (!low_disk_space)
 338                 goto out;
 339         DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
 340         ret = remove_oldest_snapshot(&sl);
 341         if (ret)
 342                 goto out;
 343         DSS_CRIT_LOG("uhuhu: not enough disk space for a single snapshot\n");
 344         ret= -ENOSPC;
 345 out:
 346         free_snapshot_list(&sl);
 347         return ret;
 348 }
 349
 350 static int pre_create_hook(void)
 351 {
 352         int ret, fds[3] = {0, 0, 0};
 353
 354         if (!conf.pre_create_hook_given) {
 355                 snapshot_creation_status = SCS_PRE_HOOK_SUCCESS;
 356                 return 0;
 357         }
 358         DSS_NOTICE_LOG("executing %s\n", conf.pre_create_hook_arg);
 359         ret = dss_exec_cmdline_pid(&pre_create_hook_pid,
 360                 conf.pre_create_hook_arg, fds);
 361         if (ret < 0)
 362                 return ret;
 363         snapshot_creation_status = SCS_PRE_HOOK_RUNNING;
 364         return ret;
 365 }
 366
 367 static int post_create_hook(void)
 368 {
 369         int ret, fds[3] = {0, 0, 0};
 370         char *cmd;
 371
 372         if (!conf.post_create_hook_given) {
 373                 snapshot_creation_status = SCS_READY;
 374                 compute_next_snapshot_time();
 375                 return 0;
 376         }
 377         cmd = make_message("%s %s", conf.post_create_hook_arg,
 378                 path_to_last_complete_snapshot);
 379         DSS_NOTICE_LOG("executing %s\n", cmd);
 380         ret = dss_exec_cmdline_pid(&post_create_hook_pid, cmd, fds);
 381         free(cmd);
 382         if (ret < 0)
 383                 return ret;
 384         snapshot_creation_status = SCS_POST_HOOK_RUNNING;
 385         return ret;
 386 }
 387
 388 static void kill_process(pid_t pid)
 389 {
 390         if (!pid)
 391                 return;
 392         DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
 393         kill(pid, SIGTERM);
 394 }
 395
 396 static void stop_rsync_process(void)
 397 {
 398         if (!rsync_pid || rsync_stopped)
 399                 return;
 400         kill(SIGSTOP, rsync_pid);
 401         rsync_stopped = 1;
 402 }
 403
 404 static void restart_rsync_process(void)
 405 {
 406         if (!rsync_pid || !rsync_stopped)
 407                 return;
 408         kill (SIGCONT, rsync_pid);
 409         rsync_stopped = 0;
 410 }
 411
 412
 413 /**
 414  * Print a log message about the exit status of a child.
 415  */
 416 static void log_termination_msg(pid_t pid, int status)
 417 {
 418         if (WIFEXITED(status))
 419                 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
 420                         WEXITSTATUS(status));
 421         else if (WIFSIGNALED(status))
 422                 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
 423                         WTERMSIG(status));
 424         else
 425                 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
 426 }
 427
 428 static int wait_for_process(pid_t pid, int *status)
 429 {
 430         int ret;
 431
 432         DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
 433         for (;;) {
 434                 fd_set rfds;
 435
 436                 FD_ZERO(&rfds);
 437                 FD_SET(signal_pipe, &rfds);
 438                 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
 439                 if (ret < 0)
 440                         break;
 441                 ret = next_signal();
 442                 if (!ret)
 443                         continue;
 444                 if (ret == SIGCHLD) {
 445                         ret = waitpid(pid, status, 0);
 446                         if (ret >= 0)
 447                                 break;
 448                         if (errno != EINTR) { /* error */
 449                                 ret = -ERRNO_TO_DSS_ERROR(errno);
 450                                 break;
 451                         }
 452                 }
 453                 /* SIGINT or SIGTERM */
 454                 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
 455                 kill(pid, SIGTERM);
 456         }
 457         if (ret < 0)
 458                 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
 459         else
 460                 log_termination_msg(pid, *status);
 461         return ret;
 462 }
 463
 464 static int handle_rm_exit(int status)
 465 {
 466         rm_pid = 0;
 467         if (!WIFEXITED(status))
 468                 return -E_INVOLUNTARY_EXIT;
 469         if (WEXITSTATUS(status))
 470                 return -E_BAD_EXIT_CODE;
 471         return 1;
 472 }
 473
 474 static int wait_for_rm_process(void)
 475 {
 476         int status, ret = wait_for_process(rm_pid, &status);
 477
 478         if (ret < 0)
 479                 return ret;
 480         return handle_rm_exit(status);
 481 }
 482
 483 static int handle_rsync_exit(int status)
 484 {
 485         int es, ret;
 486
 487         if (!WIFEXITED(status)) {
 488                 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)rsync_pid);
 489                 ret = -E_INVOLUNTARY_EXIT;
 490                 snapshot_creation_status = SCS_READY;
 491                 compute_next_snapshot_time();
 492                 goto out;
 493         }
 494         es = WEXITSTATUS(status);
 495         if (es != 0 && es != 23 && es != 24) {
 496                 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)rsync_pid, es);
 497                 ret = -E_BAD_EXIT_CODE;
 498                 snapshot_creation_status = SCS_READY;
 499                 compute_next_snapshot_time();
 500                 goto out;
 501         }
 502         ret = rename_incomplete_snapshot(current_snapshot_creation_time);
 503         if (ret < 0)
 504                 goto out;
 505         snapshot_creation_status = SCS_RSYNC_SUCCESS;
 506 out:
 507         rsync_pid = 0;
 508         rsync_stopped = 0;
 509         return ret;
 510 }
 511
 512 static int handle_pre_create_hook_exit(int status)
 513 {
 514         int es, ret;
 515
 516         if (!WIFEXITED(status)) {
 517                 snapshot_creation_status = SCS_READY;
 518                 compute_next_snapshot_time();
 519                 ret = -E_INVOLUNTARY_EXIT;
 520                 goto out;
 521         }
 522         es = WEXITSTATUS(status);
 523         if (es) {
 524                 snapshot_creation_status = SCS_READY;
 525                 compute_next_snapshot_time();
 526                 ret = -E_BAD_EXIT_CODE;
 527                 goto out;
 528         }
 529         snapshot_creation_status = SCS_PRE_HOOK_SUCCESS;
 530         ret = 1;
 531 out:
 532         pre_create_hook_pid = 0;
 533         return ret;
 534 }
 535
 536 static int handle_sigchld(void)
 537 {
 538         pid_t pid;
 539         int status, ret = reap_child(&pid, &status);
 540
 541         if (ret <= 0)
 542                 return ret;
 543         if (pid == rsync_pid)
 544                 return handle_rsync_exit(status);
 545         if (pid == rm_pid)
 546                 return handle_rm_exit(status);
 547         if (pid == pre_create_hook_pid)
 548                 return handle_pre_create_hook_exit(status);
 549         if (pid == post_create_hook_pid) {
 550                 snapshot_creation_status = SCS_READY;
 551                 compute_next_snapshot_time();
 552                 return 1;
 553         }
 554         DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
 555         exit(EXIT_FAILURE);
 556 }
 557
 558 static int check_config(void)
 559 {
 560         if (conf.unit_interval_arg <= 0) {
 561                 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
 562                 return -E_INVALID_NUMBER;
 563         }
 564         DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
 565         if (conf.num_intervals_arg <= 0) {
 566                 DSS_ERROR_LOG("bad number of intervals  %i\n", conf.num_intervals_arg);
 567                 return -E_INVALID_NUMBER;
 568         }
 569         DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
 570         return 1;
 571 }
 572
 573 /* exits on errors */
 574 static void parse_config_file(int override)
 575 {
 576         int ret;
 577         char *config_file;
 578         struct stat statbuf;
 579         char *old_logfile_arg = NULL;
 580         int old_daemon_given = 0;
 581
 582         if (conf.config_file_given)
 583                 config_file = dss_strdup(conf.config_file_arg);
 584         else {
 585                 char *home = get_homedir();
 586                 config_file = make_message("%s/.dssrc", home);
 587                 free(home);
 588         }
 589         if (override) { /* SIGHUP */
 590                 if (conf.logfile_given)
 591                         old_logfile_arg = dss_strdup(conf.logfile_arg);
 592                 old_daemon_given = conf.daemon_given;
 593         }
 594
 595         ret = stat(config_file, &statbuf);
 596         if (ret && conf.config_file_given) {
 597                 ret = -ERRNO_TO_DSS_ERROR(errno);
 598                 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
 599                 goto out;
 600         }
 601         if (!ret) {
 602                 struct cmdline_parser_params params = {
 603                         .override = override,
 604                         .initialize = 0,
 605                         .check_required = 1,
 606                         .check_ambiguity = 0
 607                 };
 608                 cmdline_parser_config_file(config_file, &conf, &params);
 609         }
 610         ret = check_config();
 611         if (ret < 0)
 612                 goto out;
 613         if (override) {
 614                 /* don't change daemon mode on SIGHUP */
 615                 conf.daemon_given = old_daemon_given;
 616                 close_log(logfile);
 617                 logfile = NULL;
 618                 if (conf.logfile_given)
 619                         free(old_logfile_arg);
 620                 else if (conf.daemon_given) { /* re-use old logfile */
 621                         conf.logfile_arg = old_logfile_arg;
 622                         conf.logfile_given = 1;
 623                 }
 624         }
 625         if (conf.logfile_given) {
 626                 logfile = open_log(conf.logfile_arg);
 627                 log_welcome(conf.loglevel_arg);
 628         }
 629         DSS_EMERG_LOG("loglevel: %d\n", conf.loglevel_arg);
 630 //      cmdline_parser_dump(logfile? logfile : stdout, &conf);
 631         ret = dss_chdir(conf.dest_dir_arg);
 632 out:
 633         free(config_file);
 634         if (ret >= 0)
 635                 return;
 636         DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
 637         exit(EXIT_FAILURE);
 638 }
 639
 640 static void handle_sighup(void)
 641 {
 642         DSS_NOTICE_LOG("SIGHUP\n");
 643         parse_config_file(1);
 644 }
 645
 646 static void handle_signal(void)
 647 {
 648         int sig, ret = next_signal();
 649
 650         if (ret <= 0)
 651                 goto out;
 652         sig = ret;
 653         switch (sig) {
 654         case SIGINT:
 655         case SIGTERM:
 656                 restart_rsync_process();
 657                 kill_process(rsync_pid);
 658                 kill_process(rm_pid);
 659                 exit(EXIT_FAILURE);
 660         case SIGHUP:
 661                 handle_sighup();
 662                 ret = 1;
 663                 break;
 664         case SIGCHLD:
 665                 ret = handle_sigchld();
 666                 break;
 667         }
 668 out:
 669         if (ret < 0)
 670                 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
 671 }
 672
 673 static void create_rsync_argv(char ***argv, int64_t *num)
 674 {
 675         char *logname, *newest;
 676         int i = 0, j;
 677         struct snapshot_list sl;
 678
 679         dss_get_snapshot_list(&sl);
 680         newest = name_of_newest_complete_snapshot(&sl);
 681         free_snapshot_list(&sl);
 682
 683         *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
 684         (*argv)[i++] = dss_strdup("rsync");
 685         (*argv)[i++] = dss_strdup("-aq");
 686         (*argv)[i++] = dss_strdup("--delete");
 687         for (j = 0; j < conf.rsync_option_given; j++)
 688                 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
 689         if (newest) {
 690                 DSS_INFO_LOG("using %s as reference snapshot\n", newest);
 691                 (*argv)[i++] = make_message("--link-dest=../%s", newest);
 692                 free(newest);
 693         } else
 694                 DSS_INFO_LOG("no previous snapshot found\n");
 695         if (conf.exclude_patterns_given) {
 696                 (*argv)[i++] = dss_strdup("--exclude-from");
 697                 (*argv)[i++] = dss_strdup(conf.exclude_patterns_arg);
 698
 699         }
 700         logname = dss_logname();
 701         if (conf.remote_user_given && !strcmp(conf.remote_user_arg, logname))
 702                 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
 703         else
 704                 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
 705                         conf.remote_user_arg : logname,
 706                         conf.remote_host_arg, conf.source_dir_arg);
 707         free(logname);
 708         *num = get_current_time();
 709         (*argv)[i++] = incomplete_name(*num);
 710         (*argv)[i++] = NULL;
 711         for (j = 0; j < i; j++)
 712                 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
 713 }
 714
 715 static void free_rsync_argv(char **argv)
 716 {
 717         int i;
 718         for (i = 0; argv[i]; i++)
 719                 free(argv[i]);
 720         free(argv);
 721 }
 722
 723 static int create_snapshot(char **argv)
 724 {
 725         int ret, fds[3] = {0, 0, 0};
 726         char *name;
 727
 728         name = incomplete_name(current_snapshot_creation_time);
 729         DSS_NOTICE_LOG("creating new snapshot %s\n", name);
 730         free(name);
 731         ret = dss_exec(&rsync_pid, argv[0], argv, fds);
 732         if (ret < 0)
 733                 return ret;
 734         snapshot_creation_status = SCS_RSYNC_RUNNING;
 735         return ret;
 736 }
 737
 738 static int select_loop(void)
 739 {
 740         int ret;
 741         struct timeval tv = {.tv_sec = 0, .tv_usec = 0};
 742
 743         for (;;) {
 744                 fd_set rfds;
 745                 int low_disk_space;
 746                 char **rsync_argv;
 747                 struct timeval now, *tvp = &tv;
 748
 749                 if (rsync_pid)
 750                         tv.tv_sec = 60; /* check every 60 seconds for free disk space */
 751                 else if (rm_pid)
 752                         tvp = NULL; /* sleep until rm process dies */
 753                 FD_ZERO(&rfds);
 754                 FD_SET(signal_pipe, &rfds);
 755                 DSS_DEBUG_LOG("tvp: %p, tv_sec: %lu\n", tvp, (long unsigned) tv.tv_sec);
 756                 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
 757                 if (ret < 0)
 758                         return ret;
 759                 if (FD_ISSET(signal_pipe, &rfds))
 760                         handle_signal();
 761                 if (rm_pid)
 762                         continue;
 763                 ret = disk_space_low();
 764                 if (ret < 0)
 765                         break;
 766                 low_disk_space = ret;
 767                 ret = try_to_free_disk_space(low_disk_space);
 768                 if (ret < 0)
 769                         break;
 770                 if (rm_pid) {
 771                         stop_rsync_process();
 772                         continue;
 773                 }
 774                 restart_rsync_process();
 775                 gettimeofday(&now, NULL);
 776                 if (tv_diff(&next_snapshot_time, &now, &tv) > 0)
 777                         continue;
 778                 switch (snapshot_creation_status) {
 779                 case SCS_READY:
 780                         ret = pre_create_hook();
 781                         if (ret < 0)
 782                                 goto out;
 783                         continue;
 784                 case SCS_PRE_HOOK_RUNNING:
 785                         continue;
 786                 case SCS_PRE_HOOK_SUCCESS:
 787                         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
 788                         ret = create_snapshot(rsync_argv);
 789                         free_rsync_argv(rsync_argv);
 790                         if (ret < 0)
 791                                 goto out;
 792                         continue;
 793                 case SCS_RSYNC_RUNNING:
 794                         continue;
 795                 case SCS_RSYNC_SUCCESS:
 796                         ret = post_create_hook();
 797                         if (ret < 0)
 798                                 goto out;
 799                         continue;
 800                 case SCS_POST_HOOK_RUNNING:
 801                         continue;
 802                 }
 803         }
 804 out:
 805         return ret;
 806 }
 807
 808 static int com_run(void)
 809 {
 810         int ret;
 811
 812         if (conf.dry_run_given) {
 813                 DSS_ERROR_LOG("dry_run not supported by this command\n");
 814                 return -E_SYNTAX;
 815         }
 816         ret = install_sighandler(SIGHUP);
 817         if (ret < 0)
 818                 return ret;
 819         compute_next_snapshot_time();
 820         return select_loop();
 821 }
 822
 823 static int com_prune(void)
 824 {
 825         int ret;
 826         struct snapshot_list sl;
 827         struct disk_space ds;
 828
 829         ret = get_disk_space(".", &ds);
 830         if (ret < 0)
 831                 return ret;
 832         log_disk_space(&ds);
 833         for (;;) {
 834                 dss_get_snapshot_list(&sl);
 835                 ret = remove_outdated_snapshot(&sl);
 836                 free_snapshot_list(&sl);
 837                 if (ret < 0)
 838                         return ret;
 839                 if (!ret)
 840                         break;
 841                 ret = wait_for_rm_process();
 842                 if (ret < 0)
 843                         goto out;
 844         }
 845         for (;;) {
 846                 dss_get_snapshot_list(&sl);
 847                 ret = remove_redundant_snapshot(&sl);
 848                 free_snapshot_list(&sl);
 849                 if (ret < 0)
 850                         return ret;
 851                 if (!ret)
 852                         break;
 853                 ret = wait_for_rm_process();
 854                 if (ret < 0)
 855                         goto out;
 856         }
 857         return 1;
 858 out:
 859         return ret;
 860 }
 861
 862 static int com_create(void)
 863 {
 864         int ret, status;
 865         char **rsync_argv;
 866
 867         if (conf.dry_run_given) {
 868                 int i;
 869                 char *msg = NULL;
 870                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
 871                 for (i = 0; rsync_argv[i]; i++) {
 872                         char *tmp = msg;
 873                         msg = make_message("%s%s%s", tmp? tmp : "",
 874                                 tmp? " " : "", rsync_argv[i]);
 875                         free(tmp);
 876                 }
 877                 free_rsync_argv(rsync_argv);
 878                 dss_msg("%s\n", msg);
 879                 free(msg);
 880                 return 1;
 881         }
 882         ret = pre_create_hook();
 883         if (ret < 0)
 884                 return ret;
 885         if (pre_create_hook_pid) {
 886                 ret = wait_for_process(pre_create_hook_pid, &status);
 887                 if (ret < 0)
 888                         return ret;
 889                 ret = handle_pre_create_hook_exit(status);
 890                 if (ret < 0)
 891                         return ret;
 892         }
 893         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
 894         ret = create_snapshot(rsync_argv);
 895         if (ret < 0)
 896                 goto out;
 897         ret = wait_for_process(rsync_pid, &status);
 898         if (ret < 0)
 899                 goto out;
 900         ret = handle_rsync_exit(status);
 901         if (ret < 0)
 902                 goto out;
 903         post_create_hook();
 904         if (post_create_hook_pid)
 905                 ret = wait_for_process(post_create_hook_pid, &status);
 906 out:
 907         free_rsync_argv(rsync_argv);
 908         return ret;
 909 }
 910
 911 static int com_ls(void)
 912 {
 913         int i;
 914         struct snapshot_list sl;
 915         struct snapshot *s;
 916
 917         dss_get_snapshot_list(&sl);
 918         FOR_EACH_SNAPSHOT(s, i, &sl)
 919                 dss_msg("%u\t%s\n", s->interval, s->name);
 920         free_snapshot_list(&sl);
 921         return 1;
 922 }
 923
 924 static void setup_signal_handling(void)
 925 {
 926         int ret;
 927
 928         DSS_INFO_LOG("setting up signal handlers\n");
 929         signal_pipe = signal_init(); /* always successful */
 930         ret = install_sighandler(SIGINT);
 931         if (ret < 0)
 932                 goto err;
 933         ret = install_sighandler(SIGTERM);
 934         if (ret < 0)
 935                 goto err;
 936         ret = install_sighandler(SIGCHLD);
 937         if (ret < 0)
 938                 goto err;
 939         return;
 940 err:
 941         DSS_EMERG_LOG("could not install signal handlers\n");
 942         exit(EXIT_FAILURE);
 943 }
 944
 945 /**
 946  * The main function of dss.
 947  *
 948  * \param argc Usual argument count.
 949  * \param argv Usual argument vector.
 950  */
 951 int main(int argc, char **argv)
 952 {
 953         int ret;
 954         struct cmdline_parser_params params = {
 955                 .override = 0,
 956                 .initialize = 1,
 957                 .check_required = 0,
 958                 .check_ambiguity = 0
 959         };
 960
 961         cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
 962         parse_config_file(0);
 963
 964         if (conf.daemon_given)
 965                 daemon_init();
 966         setup_signal_handling();
 967         ret = call_command_handler();
 968         if (ret < 0)
 969                 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
 970         exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
 971 }