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                         .print_errors = 1
 608                 };
 609                 cmdline_parser_config_file(config_file, &conf, &params);
 610         }
 611         ret = check_config();
 612         if (ret < 0)
 613                 goto out;
 614         if (override) {
 615                 /* don't change daemon mode on SIGHUP */
 616                 conf.daemon_given = old_daemon_given;
 617                 close_log(logfile);
 618                 logfile = NULL;
 619                 if (conf.logfile_given)
 620                         free(old_logfile_arg);
 621                 else if (conf.daemon_given) { /* re-use old logfile */
 622                         conf.logfile_arg = old_logfile_arg;
 623                         conf.logfile_given = 1;
 624                 }
 625         }
 626         if (conf.logfile_given) {
 627                 logfile = open_log(conf.logfile_arg);
 628                 log_welcome(conf.loglevel_arg);
 629         }
 630         DSS_EMERG_LOG("loglevel: %d\n", conf.loglevel_arg);
 631 //      cmdline_parser_dump(logfile? logfile : stdout, &conf);
 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 change_to_dest_dir(void)
 641 {
 642         int ret;
 643
 644         DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
 645         ret = dss_chdir(conf.dest_dir_arg);
 646         if (ret >= 0)
 647                 return;
 648         DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
 649         exit(EXIT_FAILURE);
 650 }
 651
 652 static void handle_sighup(void)
 653 {
 654         DSS_NOTICE_LOG("SIGHUP\n");
 655         parse_config_file(1);
 656         change_to_dest_dir();
 657 }
 658
 659 static void handle_signal(void)
 660 {
 661         int sig, ret = next_signal();
 662
 663         if (ret <= 0)
 664                 goto out;
 665         sig = ret;
 666         switch (sig) {
 667         case SIGINT:
 668         case SIGTERM:
 669                 restart_rsync_process();
 670                 kill_process(rsync_pid);
 671                 kill_process(rm_pid);
 672                 exit(EXIT_FAILURE);
 673         case SIGHUP:
 674                 handle_sighup();
 675                 ret = 1;
 676                 break;
 677         case SIGCHLD:
 678                 ret = handle_sigchld();
 679                 break;
 680         }
 681 out:
 682         if (ret < 0)
 683                 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
 684 }
 685
 686 static void create_rsync_argv(char ***argv, int64_t *num)
 687 {
 688         char *logname, *newest;
 689         int i = 0, j;
 690         struct snapshot_list sl;
 691
 692         dss_get_snapshot_list(&sl);
 693         newest = name_of_newest_complete_snapshot(&sl);
 694         free_snapshot_list(&sl);
 695
 696         *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
 697         (*argv)[i++] = dss_strdup("rsync");
 698         (*argv)[i++] = dss_strdup("-aq");
 699         (*argv)[i++] = dss_strdup("--delete");
 700         for (j = 0; j < conf.rsync_option_given; j++)
 701                 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
 702         if (newest) {
 703                 DSS_INFO_LOG("using %s as reference snapshot\n", newest);
 704                 (*argv)[i++] = make_message("--link-dest=../%s", newest);
 705                 free(newest);
 706         } else
 707                 DSS_INFO_LOG("no previous snapshot found\n");
 708         logname = dss_logname();
 709         if (conf.remote_user_given && !strcmp(conf.remote_user_arg, logname))
 710                 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
 711         else
 712                 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
 713                         conf.remote_user_arg : logname,
 714                         conf.remote_host_arg, conf.source_dir_arg);
 715         free(logname);
 716         *num = get_current_time();
 717         (*argv)[i++] = incomplete_name(*num);
 718         (*argv)[i++] = NULL;
 719         for (j = 0; j < i; j++)
 720                 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
 721 }
 722
 723 static void free_rsync_argv(char **argv)
 724 {
 725         int i;
 726         for (i = 0; argv[i]; i++)
 727                 free(argv[i]);
 728         free(argv);
 729 }
 730
 731 static int create_snapshot(char **argv)
 732 {
 733         int ret, fds[3] = {0, 0, 0};
 734         char *name;
 735
 736         name = incomplete_name(current_snapshot_creation_time);
 737         DSS_NOTICE_LOG("creating new snapshot %s\n", name);
 738         free(name);
 739         ret = dss_exec(&rsync_pid, argv[0], argv, fds);
 740         if (ret < 0)
 741                 return ret;
 742         snapshot_creation_status = SCS_RSYNC_RUNNING;
 743         return ret;
 744 }
 745
 746 static int select_loop(void)
 747 {
 748         int ret;
 749         /* check every 60 seconds for free disk space */
 750         struct timeval tv = {.tv_sec = 60, .tv_usec = 0};
 751
 752         for (;;) {
 753                 fd_set rfds;
 754                 int low_disk_space;
 755                 char **rsync_argv;
 756                 struct timeval now, *tvp = &tv;
 757
 758                 if (rm_pid)
 759                         tvp = NULL; /* sleep until rm process dies */
 760                 FD_ZERO(&rfds);
 761                 FD_SET(signal_pipe, &rfds);
 762                 DSS_DEBUG_LOG("tvp: %p, tv_sec: %lu\n", tvp, (long unsigned) tv.tv_sec);
 763                 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
 764                 if (ret < 0)
 765                         return ret;
 766                 if (FD_ISSET(signal_pipe, &rfds))
 767                         handle_signal();
 768                 if (rm_pid)
 769                         continue;
 770                 ret = disk_space_low();
 771                 if (ret < 0)
 772                         break;
 773                 low_disk_space = ret;
 774                 ret = try_to_free_disk_space(low_disk_space);
 775                 if (ret < 0)
 776                         break;
 777                 if (rm_pid) {
 778                         stop_rsync_process();
 779                         continue;
 780                 }
 781                 restart_rsync_process();
 782                 gettimeofday(&now, NULL);
 783                 if (tv_diff(&next_snapshot_time, &now, NULL) > 0)
 784                         continue;
 785                 switch (snapshot_creation_status) {
 786                 case SCS_READY:
 787                         ret = pre_create_hook();
 788                         if (ret < 0)
 789                                 goto out;
 790                         continue;
 791                 case SCS_PRE_HOOK_RUNNING:
 792                         continue;
 793                 case SCS_PRE_HOOK_SUCCESS:
 794                         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
 795                         ret = create_snapshot(rsync_argv);
 796                         free_rsync_argv(rsync_argv);
 797                         if (ret < 0)
 798                                 goto out;
 799                         continue;
 800                 case SCS_RSYNC_RUNNING:
 801                         continue;
 802                 case SCS_RSYNC_SUCCESS:
 803                         ret = post_create_hook();
 804                         if (ret < 0)
 805                                 goto out;
 806                         continue;
 807                 case SCS_POST_HOOK_RUNNING:
 808                         continue;
 809                 }
 810         }
 811 out:
 812         return ret;
 813 }
 814
 815 static int com_run(void)
 816 {
 817         int ret;
 818
 819         if (conf.dry_run_given) {
 820                 DSS_ERROR_LOG("dry_run not supported by this command\n");
 821                 return -E_SYNTAX;
 822         }
 823         ret = install_sighandler(SIGHUP);
 824         if (ret < 0)
 825                 return ret;
 826         compute_next_snapshot_time();
 827         return select_loop();
 828 }
 829
 830 static int com_prune(void)
 831 {
 832         int ret;
 833         struct snapshot_list sl;
 834         struct disk_space ds;
 835
 836         ret = get_disk_space(".", &ds);
 837         if (ret < 0)
 838                 return ret;
 839         log_disk_space(&ds);
 840         for (;;) {
 841                 dss_get_snapshot_list(&sl);
 842                 ret = remove_outdated_snapshot(&sl);
 843                 free_snapshot_list(&sl);
 844                 if (ret < 0)
 845                         return ret;
 846                 if (!ret)
 847                         break;
 848                 ret = wait_for_rm_process();
 849                 if (ret < 0)
 850                         goto out;
 851         }
 852         for (;;) {
 853                 dss_get_snapshot_list(&sl);
 854                 ret = remove_redundant_snapshot(&sl);
 855                 free_snapshot_list(&sl);
 856                 if (ret < 0)
 857                         return ret;
 858                 if (!ret)
 859                         break;
 860                 ret = wait_for_rm_process();
 861                 if (ret < 0)
 862                         goto out;
 863         }
 864         return 1;
 865 out:
 866         return ret;
 867 }
 868
 869 static int com_create(void)
 870 {
 871         int ret, status;
 872         char **rsync_argv;
 873
 874         if (conf.dry_run_given) {
 875                 int i;
 876                 char *msg = NULL;
 877                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
 878                 for (i = 0; rsync_argv[i]; i++) {
 879                         char *tmp = msg;
 880                         msg = make_message("%s%s%s", tmp? tmp : "",
 881                                 tmp? " " : "", rsync_argv[i]);
 882                         free(tmp);
 883                 }
 884                 free_rsync_argv(rsync_argv);
 885                 dss_msg("%s\n", msg);
 886                 free(msg);
 887                 return 1;
 888         }
 889         ret = pre_create_hook();
 890         if (ret < 0)
 891                 return ret;
 892         if (pre_create_hook_pid) {
 893                 ret = wait_for_process(pre_create_hook_pid, &status);
 894                 if (ret < 0)
 895                         return ret;
 896                 ret = handle_pre_create_hook_exit(status);
 897                 if (ret < 0)
 898                         return ret;
 899         }
 900         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
 901         ret = create_snapshot(rsync_argv);
 902         if (ret < 0)
 903                 goto out;
 904         ret = wait_for_process(rsync_pid, &status);
 905         if (ret < 0)
 906                 goto out;
 907         ret = handle_rsync_exit(status);
 908         if (ret < 0)
 909                 goto out;
 910         post_create_hook();
 911         if (post_create_hook_pid)
 912                 ret = wait_for_process(post_create_hook_pid, &status);
 913 out:
 914         free_rsync_argv(rsync_argv);
 915         return ret;
 916 }
 917
 918 static int com_ls(void)
 919 {
 920         int i;
 921         struct snapshot_list sl;
 922         struct snapshot *s;
 923
 924         dss_get_snapshot_list(&sl);
 925         FOR_EACH_SNAPSHOT(s, i, &sl)
 926                 dss_msg("%u\t%s\n", s->interval, s->name);
 927         free_snapshot_list(&sl);
 928         return 1;
 929 }
 930
 931 static void setup_signal_handling(void)
 932 {
 933         int ret;
 934
 935         DSS_INFO_LOG("setting up signal handlers\n");
 936         signal_pipe = signal_init(); /* always successful */
 937         ret = install_sighandler(SIGINT);
 938         if (ret < 0)
 939                 goto err;
 940         ret = install_sighandler(SIGTERM);
 941         if (ret < 0)
 942                 goto err;
 943         ret = install_sighandler(SIGCHLD);
 944         if (ret < 0)
 945                 goto err;
 946         return;
 947 err:
 948         DSS_EMERG_LOG("could not install signal handlers\n");
 949         exit(EXIT_FAILURE);
 950 }
 951
 952 /**
 953  * The main function of dss.
 954  *
 955  * \param argc Usual argument count.
 956  * \param argv Usual argument vector.
 957  */
 958 int main(int argc, char **argv)
 959 {
 960         int ret;
 961         struct cmdline_parser_params params = {
 962                 .override = 0,
 963                 .initialize = 1,
 964                 .check_required = 0,
 965                 .check_ambiguity = 0,
 966                 .print_errors = 1
 967         };
 968
 969         cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
 970         parse_config_file(0);
 971
 972         if (conf.daemon_given)
 973                 daemon_init();
 974         change_to_dest_dir();
 975         setup_signal_handling();
 976         ret = call_command_handler();
 977         if (ret < 0)
 978                 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
 979         exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
 980 }