dss.c

   1 /*
   2  * Copyright (C) 2008 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 rsync process. */
  44 static pid_t rsync_pid;
  45 /** Whether the rsync process is currently stopped */
  46 static int rsync_stopped;
  47 /** Process id of current rm process. */
  48 static pid_t rm_pid;
  49 /** When the next snapshot is due. */
  50 static struct timeval next_snapshot_time;
  51 /** The pid of the pre-create hook. */
  52 static pid_t pre_create_hook_pid;
  53 /** The pid of the post-create hook. */
  54 static pid_t post_create_hook_pid;
  55 /** Creation time of the snapshot currently being created. */
  56 static int64_t current_snapshot_creation_time;
  57 /** Needed by the post-create hook. */
  58 static char *path_to_last_complete_snapshot;
  59 /** \sa \ref snap.h for details. */
  60 static unsigned snapshot_creation_status;
  61
  62
  63 DEFINE_DSS_ERRLIST;
  64
  65
  66 /* a litte cpp magic helps to DRY */
  67 #define COMMANDS \
  68         COMMAND(ls) \
  69         COMMAND(create) \
  70         COMMAND(prune) \
  71         COMMAND(run)
  72 #define COMMAND(x) static int com_ ##x(void);
  73 COMMANDS
  74 #undef COMMAND
  75 #define COMMAND(x) if (conf.x ##_given) return com_ ##x();
  76 static int call_command_handler(void)
  77 {
  78         COMMANDS
  79         DSS_EMERG_LOG("BUG: did not find command handler\n");
  80         return -E_BUG;
  81 }
  82 #undef COMMAND
  83 #undef COMMANDS
  84
  85 /**
  86  * The log function of dss.
  87  *
  88  * \param ll Loglevel.
  89  * \param fml Usual format string.
  90  *
  91  * All DSS_XXX_LOG() macros use this function.
  92  */
  93 __printf_2_3 void dss_log(int ll, const char* fmt,...)
  94 {
  95         va_list argp;
  96         FILE *outfd;
  97         struct tm *tm;
  98         time_t t1;
  99         char str[255] = "";
 100
 101         if (ll < conf.loglevel_arg)
 102                 return;
 103         outfd = logfile? logfile : stderr;
 104         time(&t1);
 105         tm = localtime(&t1);
 106         strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
 107         fprintf(outfd, "%s ", str);
 108         if (conf.loglevel_arg <= INFO)
 109                 fprintf(outfd, "%i: ", ll);
 110         va_start(argp, fmt);
 111         vfprintf(outfd, fmt, argp);
 112         va_end(argp);
 113 }
 114
 115 /**
 116  * Print a message either to stdout or to the log file.
 117  */
 118 static __printf_1_2 void dss_msg(const char* fmt,...)
 119 {
 120         FILE *outfd = conf.daemon_given? logfile : stdout;
 121         va_list argp;
 122         va_start(argp, fmt);
 123         vfprintf(outfd, fmt, argp);
 124         va_end(argp);
 125 }
 126
 127 static int disk_space_low(void)
 128 {
 129         struct disk_space ds;
 130         int ret = get_disk_space(".", &ds);
 131
 132         if (ret < 0)
 133                 return ret;
 134         if (conf.min_free_mb_arg)
 135                 if (ds.free_mb < conf.min_free_mb_arg)
 136                         return 1;
 137         if (conf.min_free_percent_arg)
 138                 if (ds.percent_free < conf.min_free_percent_arg)
 139                         return 1;
 140         if (conf.min_free_percent_inodes_arg)
 141                 if (ds.percent_free_inodes < conf.min_free_percent_inodes_arg)
 142                         return 1;
 143         return 0;
 144 }
 145
 146 static void dss_get_snapshot_list(struct snapshot_list *sl)
 147 {
 148         get_snapshot_list(sl, conf.unit_interval_arg, conf.num_intervals_arg);
 149 }
 150
 151 static void compute_next_snapshot_time(void)
 152 {
 153         struct timeval now, unit_interval = {.tv_sec = 24 * 3600 * conf.unit_interval_arg},
 154                 tmp, diff;
 155         int64_t x = 0;
 156         unsigned wanted = desired_number_of_snapshots(0, conf.num_intervals_arg),
 157                 num_complete_snapshots = 0;
 158         int i, ret;
 159         struct snapshot *s = NULL;
 160         struct snapshot_list sl;
 161
 162         assert(snapshot_creation_status == SCS_READY);
 163         current_snapshot_creation_time = 0;
 164         dss_get_snapshot_list(&sl);
 165         FOR_EACH_SNAPSHOT(s, i, &sl) {
 166                 if (!(s->flags & SS_COMPLETE))
 167                         continue;
 168                 num_complete_snapshots++;
 169                 x += s->completion_time - s->creation_time;
 170         }
 171         assert(x >= 0);
 172         if (num_complete_snapshots)
 173                 x /= num_complete_snapshots; /* avg time to create one snapshot */
 174         x *= wanted; /* time to create all snapshots in interval 0 */
 175         tmp.tv_sec = x;
 176         tmp.tv_usec = 0;
 177         ret = tv_diff(&unit_interval, &tmp, &diff); /* total sleep time per unit interval */
 178         if (ret < 0 || !s) /* unit_interval < tmp or no snapshot */
 179                 goto min_sleep;
 180         tv_divide(wanted, &diff, &tmp); /* sleep time betweeen two snapshots */
 181         diff.tv_sec = s->completion_time; /* completion time of the the latest snaphot */
 182         diff.tv_usec = 0;
 183         tv_add(&diff, &tmp, &next_snapshot_time);
 184         gettimeofday(&now, NULL);
 185         if (tv_diff(&now, &next_snapshot_time, NULL) < 0)
 186                 goto out;
 187 min_sleep:
 188         next_snapshot_time = now;
 189         next_snapshot_time.tv_sec += 60;
 190 out:
 191         free_snapshot_list(&sl);
 192 }
 193
 194
 195 static int remove_snapshot(struct snapshot *s)
 196 {
 197         int fds[3] = {0, 0, 0};
 198         assert(!rm_pid);
 199         char *new_name = being_deleted_name(s);
 200         int ret = dss_rename(s->name, new_name);
 201         char *argv[] = {"rm", "-rf", new_name, NULL};
 202
 203         if (ret < 0)
 204                 goto out;
 205         DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
 206         ret = dss_exec(&rm_pid, argv[0], argv, fds);
 207 out:
 208         free(new_name);
 209         return ret;
 210 }
 211
 212 /*
 213  * return: 0: no redundant snapshots, 1: rm process started, negative: error
 214  */
 215 static int remove_redundant_snapshot(struct snapshot_list *sl)
 216 {
 217         int ret, i, interval;
 218         struct snapshot *s;
 219         unsigned missing = 0;
 220
 221         DSS_DEBUG_LOG("looking for intervals containing too many snapshots\n");
 222         for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
 223                 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
 224                 unsigned num = sl->interval_count[interval];
 225                 struct snapshot *victim = NULL, *prev = NULL;
 226                 int64_t score = LONG_MAX;
 227
 228                 if (keep >= num)
 229                         missing += keep - num;
 230 //              DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
 231 //                      interval, keep, num, missing);
 232                 if (keep + missing >= num)
 233                         continue;
 234                 /* redundant snapshot in this interval, pick snapshot with lowest score */
 235                 FOR_EACH_SNAPSHOT(s, i, sl) {
 236                         int64_t this_score;
 237
 238                         //DSS_DEBUG_LOG("checking %s\n", s->name);
 239                         if (s->interval > interval) {
 240                                 prev = s;
 241                                 continue;
 242                         }
 243                         if (s->interval < interval)
 244                                 break;
 245                         if (!victim) {
 246                                 victim = s;
 247                                 prev = s;
 248                                 continue;
 249                         }
 250                         assert(prev);
 251                         /* check if s is a better victim */
 252                         this_score = s->creation_time - prev->creation_time;
 253                         assert(this_score >= 0);
 254                         //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
 255                         if (this_score < score) {
 256                                 score = this_score;
 257                                 victim = s;
 258                         }
 259                         prev = s;
 260                 }
 261                 assert(victim);
 262                 if (conf.dry_run_given) {
 263                         dss_msg("%s would be removed (interval = %i)\n",
 264                                 victim->name, victim->interval);
 265                         continue;
 266                 }
 267                 ret = remove_snapshot(victim);
 268                 return ret < 0? ret : 1;
 269         }
 270         return 0;
 271 }
 272
 273 static int remove_outdated_snapshot(struct snapshot_list *sl)
 274 {
 275         int i, ret;
 276         struct snapshot *s;
 277
 278         DSS_DEBUG_LOG("looking for snapshots belonging to intervals greater than %d\n",
 279                 conf.num_intervals_arg);
 280         FOR_EACH_SNAPSHOT(s, i, sl) {
 281                 if (s->interval <= conf.num_intervals_arg)
 282                         continue;
 283                 if (conf.dry_run_given) {
 284                         dss_msg("%s would be removed (interval = %i)\n",
 285                                 s->name, s->interval);
 286                         continue;
 287                 }
 288                 ret = remove_snapshot(s);
 289                 if (ret < 0)
 290                         return ret;
 291                 return 1;
 292         }
 293         return 0;
 294 }
 295
 296 static int remove_oldest_snapshot(struct snapshot_list *sl)
 297 {
 298         struct snapshot *s = get_oldest_snapshot(sl);
 299
 300         if (!s) /* no snapshot found */
 301                 return 0;
 302         DSS_INFO_LOG("oldest snapshot: %s\n", s->name);
 303         if (s->creation_time == current_snapshot_creation_time)
 304                 return 0; /* do not remove the snapshot currently being created */
 305         return remove_snapshot(s);
 306 }
 307
 308 static int rename_incomplete_snapshot(int64_t start)
 309 {
 310         char *old_name;
 311         int ret;
 312
 313         free(path_to_last_complete_snapshot);
 314         ret = complete_name(start, get_current_time(),
 315                 &path_to_last_complete_snapshot);
 316         if (ret < 0)
 317                 return ret;
 318         old_name = incomplete_name(start);
 319         ret = dss_rename(old_name, path_to_last_complete_snapshot);
 320         if (ret >= 0)
 321                 DSS_NOTICE_LOG("%s -> %s\n", old_name,
 322                         path_to_last_complete_snapshot);
 323         free(old_name);
 324         return ret;
 325 }
 326
 327 static int try_to_free_disk_space(int low_disk_space)
 328 {
 329         int ret;
 330         struct snapshot_list sl;
 331
 332         if (!low_disk_space && conf.keep_redundant_given)
 333                 return 0;
 334         dss_get_snapshot_list(&sl);
 335         ret = remove_outdated_snapshot(&sl);
 336         if (ret) /* error, or we are removing something */
 337                 goto out;
 338         /* no outdated snapshot */
 339         ret = remove_redundant_snapshot(&sl);
 340         if (ret)
 341                 goto out;
 342         ret = 0;
 343         if (!low_disk_space)
 344                 goto out;
 345         DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
 346         ret = remove_oldest_snapshot(&sl);
 347         if (ret)
 348                 goto out;
 349         DSS_CRIT_LOG("uhuhu: not enough disk space for a single snapshot\n");
 350         ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
 351 out:
 352         free_snapshot_list(&sl);
 353         return ret;
 354 }
 355
 356 static int pre_create_hook(void)
 357 {
 358         int ret, fds[3] = {0, 0, 0};
 359
 360         if (!conf.pre_create_hook_given) {
 361                 snapshot_creation_status = SCS_PRE_HOOK_SUCCESS;
 362                 return 0;
 363         }
 364         DSS_NOTICE_LOG("executing %s\n", conf.pre_create_hook_arg);
 365         ret = dss_exec_cmdline_pid(&pre_create_hook_pid,
 366                 conf.pre_create_hook_arg, fds);
 367         if (ret < 0)
 368                 return ret;
 369         snapshot_creation_status = SCS_PRE_HOOK_RUNNING;
 370         return ret;
 371 }
 372
 373 static int post_create_hook(void)
 374 {
 375         int ret, fds[3] = {0, 0, 0};
 376         char *cmd;
 377
 378         if (!conf.post_create_hook_given) {
 379                 snapshot_creation_status = SCS_READY;
 380                 compute_next_snapshot_time();
 381                 return 0;
 382         }
 383         cmd = make_message("%s %s", conf.post_create_hook_arg,
 384                 path_to_last_complete_snapshot);
 385         DSS_NOTICE_LOG("executing %s\n", cmd);
 386         ret = dss_exec_cmdline_pid(&post_create_hook_pid, cmd, fds);
 387         free(cmd);
 388         if (ret < 0)
 389                 return ret;
 390         snapshot_creation_status = SCS_POST_HOOK_RUNNING;
 391         return ret;
 392 }
 393
 394 static void kill_process(pid_t pid)
 395 {
 396         if (!pid)
 397                 return;
 398         DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
 399         kill(pid, SIGTERM);
 400 }
 401
 402 static void stop_rsync_process(void)
 403 {
 404         if (!rsync_pid || rsync_stopped)
 405                 return;
 406         kill(SIGSTOP, rsync_pid);
 407         rsync_stopped = 1;
 408 }
 409
 410 static void restart_rsync_process(void)
 411 {
 412         if (!rsync_pid || !rsync_stopped)
 413                 return;
 414         kill (SIGCONT, rsync_pid);
 415         rsync_stopped = 0;
 416 }
 417
 418
 419 /**
 420  * Print a log message about the exit status of a child.
 421  */
 422 static void log_termination_msg(pid_t pid, int status)
 423 {
 424         if (WIFEXITED(status))
 425                 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
 426                         WEXITSTATUS(status));
 427         else if (WIFSIGNALED(status))
 428                 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
 429                         WTERMSIG(status));
 430         else
 431                 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
 432 }
 433
 434 static int wait_for_process(pid_t pid, int *status)
 435 {
 436         int ret;
 437
 438         DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
 439         for (;;) {
 440                 fd_set rfds;
 441
 442                 FD_ZERO(&rfds);
 443                 FD_SET(signal_pipe, &rfds);
 444                 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
 445                 if (ret < 0)
 446                         break;
 447                 ret = next_signal();
 448                 if (!ret)
 449                         continue;
 450                 if (ret == SIGCHLD) {
 451                         ret = waitpid(pid, status, 0);
 452                         if (ret >= 0)
 453                                 break;
 454                         if (errno != EINTR) { /* error */
 455                                 ret = -ERRNO_TO_DSS_ERROR(errno);
 456                                 break;
 457                         }
 458                 }
 459                 /* SIGINT or SIGTERM */
 460                 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
 461                 kill(pid, SIGTERM);
 462         }
 463         if (ret < 0)
 464                 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
 465         else
 466                 log_termination_msg(pid, *status);
 467         return ret;
 468 }
 469
 470 static int handle_rm_exit(int status)
 471 {
 472         rm_pid = 0;
 473         if (!WIFEXITED(status))
 474                 return -E_INVOLUNTARY_EXIT;
 475         if (WEXITSTATUS(status))
 476                 return -E_BAD_EXIT_CODE;
 477         return 1;
 478 }
 479
 480 static int wait_for_rm_process(void)
 481 {
 482         int status, ret = wait_for_process(rm_pid, &status);
 483
 484         if (ret < 0)
 485                 return ret;
 486         return handle_rm_exit(status);
 487 }
 488
 489 static int handle_rsync_exit(int status)
 490 {
 491         int es, ret;
 492
 493         if (!WIFEXITED(status)) {
 494                 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)rsync_pid);
 495                 ret = -E_INVOLUNTARY_EXIT;
 496                 snapshot_creation_status = SCS_READY;
 497                 compute_next_snapshot_time();
 498                 goto out;
 499         }
 500         es = WEXITSTATUS(status);
 501         if (es == 13) { /* Errors with program diagnostics */
 502                 DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
 503                         (int)rsync_pid, es);
 504                 snapshot_creation_status = SCS_RSYNC_NEEDS_RESTART;
 505                 gettimeofday(&next_snapshot_time, NULL);
 506                 next_snapshot_time.tv_sec += 60;
 507                 ret = 1;
 508                 goto out;
 509         }
 510         if (es != 0 && es != 23 && es != 24) {
 511                 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)rsync_pid, es);
 512                 ret = -E_BAD_EXIT_CODE;
 513                 snapshot_creation_status = SCS_READY;
 514                 compute_next_snapshot_time();
 515                 goto out;
 516         }
 517         ret = rename_incomplete_snapshot(current_snapshot_creation_time);
 518         if (ret < 0)
 519                 goto out;
 520         snapshot_creation_status = SCS_RSYNC_SUCCESS;
 521 out:
 522         rsync_pid = 0;
 523         rsync_stopped = 0;
 524         return ret;
 525 }
 526
 527 static int handle_pre_create_hook_exit(int status)
 528 {
 529         int es, ret;
 530
 531         if (!WIFEXITED(status)) {
 532                 snapshot_creation_status = SCS_READY;
 533                 compute_next_snapshot_time();
 534                 ret = -E_INVOLUNTARY_EXIT;
 535                 goto out;
 536         }
 537         es = WEXITSTATUS(status);
 538         if (es) {
 539                 snapshot_creation_status = SCS_READY;
 540                 compute_next_snapshot_time();
 541                 ret = -E_BAD_EXIT_CODE;
 542                 goto out;
 543         }
 544         snapshot_creation_status = SCS_PRE_HOOK_SUCCESS;
 545         ret = 1;
 546 out:
 547         pre_create_hook_pid = 0;
 548         return ret;
 549 }
 550
 551 static int handle_sigchld(void)
 552 {
 553         pid_t pid;
 554         int status, ret = reap_child(&pid, &status);
 555
 556         if (ret <= 0)
 557                 return ret;
 558         if (pid == rsync_pid)
 559                 return handle_rsync_exit(status);
 560         if (pid == rm_pid)
 561                 return handle_rm_exit(status);
 562         if (pid == pre_create_hook_pid)
 563                 return handle_pre_create_hook_exit(status);
 564         if (pid == post_create_hook_pid) {
 565                 snapshot_creation_status = SCS_READY;
 566                 compute_next_snapshot_time();
 567                 return 1;
 568         }
 569         DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
 570         return -E_BUG;
 571 }
 572
 573 static int check_config(void)
 574 {
 575         if (conf.unit_interval_arg <= 0) {
 576                 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
 577                 return -E_INVALID_NUMBER;
 578         }
 579         DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
 580         if (conf.num_intervals_arg <= 0) {
 581                 DSS_ERROR_LOG("bad number of intervals  %i\n", conf.num_intervals_arg);
 582                 return -E_INVALID_NUMBER;
 583         }
 584         DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
 585         return 1;
 586 }
 587
 588 static int parse_config_file(int override)
 589 {
 590         int ret;
 591         char *config_file;
 592         struct stat statbuf;
 593         char *old_logfile_arg = NULL;
 594         int old_daemon_given = 0;
 595
 596         if (conf.config_file_given)
 597                 config_file = dss_strdup(conf.config_file_arg);
 598         else {
 599                 char *home = get_homedir();
 600                 config_file = make_message("%s/.dssrc", home);
 601                 free(home);
 602         }
 603         if (override) { /* SIGHUP */
 604                 if (conf.logfile_given)
 605                         old_logfile_arg = dss_strdup(conf.logfile_arg);
 606                 old_daemon_given = conf.daemon_given;
 607         }
 608
 609         ret = stat(config_file, &statbuf);
 610         if (ret && conf.config_file_given) {
 611                 ret = -ERRNO_TO_DSS_ERROR(errno);
 612                 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
 613                 goto out;
 614         }
 615         if (!ret) {
 616                 struct cmdline_parser_params params = {
 617                         .override = override,
 618                         .initialize = 0,
 619                         .check_required = 1,
 620                         .check_ambiguity = 0,
 621                         .print_errors = 1
 622                 };
 623                 if (override) { /* invalidate all rsync options */
 624                         int i;
 625
 626                         for (i = 0; i < conf.rsync_option_given; i++) {
 627                                 free(conf.rsync_option_arg[i]);
 628                                 conf.rsync_option_arg[i] = NULL;
 629                         }
 630                         conf.rsync_option_given = 0;
 631                 }
 632                 cmdline_parser_config_file(config_file, &conf, &params);
 633         }
 634         ret = check_config();
 635         if (ret < 0)
 636                 goto out;
 637         if (override) {
 638                 /* don't change daemon mode on SIGHUP */
 639                 conf.daemon_given = old_daemon_given;
 640                 close_log(logfile);
 641                 logfile = NULL;
 642                 if (conf.logfile_given)
 643                         free(old_logfile_arg);
 644                 else if (conf.daemon_given) { /* re-use old logfile */
 645                         conf.logfile_arg = old_logfile_arg;
 646                         conf.logfile_given = 1;
 647                 }
 648         }
 649         if (conf.logfile_given) {
 650                 logfile = open_log(conf.logfile_arg);
 651                 log_welcome(conf.loglevel_arg);
 652         }
 653         DSS_DEBUG_LOG("loglevel: %d\n", conf.loglevel_arg);
 654 //      cmdline_parser_dump(logfile? logfile : stdout, &conf);
 655 out:
 656         free(config_file);
 657         if (ret < 0)
 658                 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
 659         return ret;
 660 }
 661
 662 static int change_to_dest_dir(void)
 663 {
 664         DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
 665         return dss_chdir(conf.dest_dir_arg);
 666 }
 667
 668 static int handle_sighup(void)
 669 {
 670         int ret;
 671
 672         DSS_NOTICE_LOG("SIGHUP\n");
 673         ret = parse_config_file(1);
 674         if (ret < 0)
 675                 return ret;
 676         return change_to_dest_dir();
 677 }
 678
 679 static int handle_signal(void)
 680 {
 681         int sig, ret = next_signal();
 682
 683         if (ret <= 0)
 684                 goto out;
 685         sig = ret;
 686         switch (sig) {
 687         case SIGINT:
 688         case SIGTERM:
 689                 restart_rsync_process();
 690                 kill_process(rsync_pid);
 691                 kill_process(rm_pid);
 692                 ret = -E_SIGNAL;
 693                 break;
 694         case SIGHUP:
 695                 ret = handle_sighup();
 696                 break;
 697         case SIGCHLD:
 698                 ret = handle_sigchld();
 699                 break;
 700         }
 701 out:
 702         if (ret < 0)
 703                 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
 704         return ret;
 705 }
 706
 707 /*
 708  * We can not use rsync locally if the local user is different from the remote
 709  * user or if the src dir is not on the local host (or both).
 710  */
 711 static int use_rsync_locally(char *logname)
 712 {
 713         char *h = conf.remote_host_arg;
 714
 715         if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
 716                 return 0;
 717         if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
 718                 return 0;
 719         return 1;
 720 }
 721
 722 static void create_rsync_argv(char ***argv, int64_t *num)
 723 {
 724         char *logname, *newest;
 725         int i = 0, j;
 726         struct snapshot_list sl;
 727
 728         dss_get_snapshot_list(&sl);
 729         newest = name_of_newest_complete_snapshot(&sl);
 730         free_snapshot_list(&sl);
 731
 732         *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
 733         (*argv)[i++] = dss_strdup("rsync");
 734         (*argv)[i++] = dss_strdup("-aq");
 735         (*argv)[i++] = dss_strdup("--delete");
 736         for (j = 0; j < conf.rsync_option_given; j++)
 737                 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
 738         if (newest) {
 739                 DSS_INFO_LOG("using %s as reference snapshot\n", newest);
 740                 (*argv)[i++] = make_message("--link-dest=../%s", newest);
 741                 free(newest);
 742         } else
 743                 DSS_INFO_LOG("no previous snapshot found\n");
 744         logname = dss_logname();
 745         if (use_rsync_locally(logname))
 746                 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
 747         else
 748                 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
 749                         conf.remote_user_arg : logname,
 750                         conf.remote_host_arg, conf.source_dir_arg);
 751         free(logname);
 752         *num = get_current_time();
 753         (*argv)[i++] = incomplete_name(*num);
 754         (*argv)[i++] = NULL;
 755         for (j = 0; j < i; j++)
 756                 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
 757 }
 758
 759 static void free_rsync_argv(char **argv)
 760 {
 761         int i;
 762
 763         if (!argv)
 764                 return;
 765         for (i = 0; argv[i]; i++)
 766                 free(argv[i]);
 767         free(argv);
 768 }
 769
 770 static int create_snapshot(char **argv)
 771 {
 772         int ret, fds[3] = {0, 0, 0};
 773         char *name;
 774
 775         name = incomplete_name(current_snapshot_creation_time);
 776         DSS_NOTICE_LOG("creating new snapshot %s\n", name);
 777         free(name);
 778         ret = dss_exec(&rsync_pid, argv[0], argv, fds);
 779         if (ret < 0)
 780                 return ret;
 781         snapshot_creation_status = SCS_RSYNC_RUNNING;
 782         return ret;
 783 }
 784
 785 static int select_loop(void)
 786 {
 787         int ret;
 788         /* check every 60 seconds for free disk space */
 789         struct timeval tv;
 790         char **rsync_argv = NULL;
 791
 792         for (;;) {
 793                 fd_set rfds;
 794                 int low_disk_space;
 795                 struct timeval now, *tvp;
 796
 797                 if (rm_pid)
 798                         tvp = NULL; /* sleep until rm process dies */
 799                 else { /* sleep one minute */
 800                         tv.tv_sec = 60;
 801                         tv.tv_usec = 0;
 802                         tvp = &tv;
 803                 }
 804                 FD_ZERO(&rfds);
 805                 FD_SET(signal_pipe, &rfds);
 806                 DSS_DEBUG_LOG("tvp: %p, tv_sec : %lu\n", tvp, (long unsigned) tv.tv_sec);
 807                 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
 808                 if (ret < 0)
 809                         goto out;
 810                 if (FD_ISSET(signal_pipe, &rfds)) {
 811                         ret = handle_signal();
 812                         if (ret < 0)
 813                                 goto out;
 814                 }
 815                 if (rm_pid)
 816                         continue;
 817                 ret = disk_space_low();
 818                 if (ret < 0)
 819                         goto out;
 820                 low_disk_space = ret;
 821                 ret = try_to_free_disk_space(low_disk_space);
 822                 if (ret < 0)
 823                         goto out;
 824                 if (rm_pid) {
 825                         stop_rsync_process();
 826                         continue;
 827                 }
 828                 restart_rsync_process();
 829                 gettimeofday(&now, NULL);
 830                 if (tv_diff(&next_snapshot_time, &now, NULL) > 0)
 831                         continue;
 832                 switch (snapshot_creation_status) {
 833                 case SCS_READY:
 834                         ret = pre_create_hook();
 835                         if (ret < 0)
 836                                 goto out;
 837                         continue;
 838                 case SCS_PRE_HOOK_RUNNING:
 839                         continue;
 840                 case SCS_RSYNC_NEEDS_RESTART:
 841                         ret = create_snapshot(rsync_argv);
 842                         if (ret < 0)
 843                                 goto out;
 844                         continue;
 845                 case SCS_PRE_HOOK_SUCCESS:
 846                         free_rsync_argv(rsync_argv);
 847                         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
 848                         ret = create_snapshot(rsync_argv);
 849                         if (ret < 0)
 850                                 goto out;
 851                         continue;
 852                 case SCS_RSYNC_RUNNING:
 853                         continue;
 854                 case SCS_RSYNC_SUCCESS:
 855                         ret = post_create_hook();
 856                         if (ret < 0)
 857                                 goto out;
 858                         continue;
 859                 case SCS_POST_HOOK_RUNNING:
 860                         continue;
 861                 }
 862         }
 863 out:
 864         return ret;
 865 }
 866
 867 static void exit_hook(int exit_code)
 868 {
 869         int fds[3] = {0, 0, 0};
 870         char *argv[] = {conf.exit_hook_arg, dss_strerror(-exit_code), NULL};
 871         pid_t pid;
 872
 873         if (!conf.exit_hook_given)
 874                 return;
 875         DSS_NOTICE_LOG("executing %s %s\n", argv[0], argv[1]);
 876         dss_exec(&pid, conf.exit_hook_arg, argv, fds);
 877 }
 878
 879 static int com_run(void)
 880 {
 881         int ret;
 882
 883         if (conf.dry_run_given) {
 884                 DSS_ERROR_LOG("dry_run not supported by this command\n");
 885                 return -E_SYNTAX;
 886         }
 887         ret = install_sighandler(SIGHUP);
 888         if (ret < 0)
 889                 return ret;
 890         compute_next_snapshot_time();
 891         ret = select_loop();
 892         if (ret >= 0) /* impossible */
 893                 ret = -E_BUG;
 894         exit_hook(ret);
 895         return ret;
 896 }
 897
 898 static int com_prune(void)
 899 {
 900         int ret;
 901         struct snapshot_list sl;
 902         struct disk_space ds;
 903
 904         ret = get_disk_space(".", &ds);
 905         if (ret < 0)
 906                 return ret;
 907         log_disk_space(&ds);
 908         for (;;) {
 909                 dss_get_snapshot_list(&sl);
 910                 ret = remove_outdated_snapshot(&sl);
 911                 free_snapshot_list(&sl);
 912                 if (ret < 0)
 913                         return ret;
 914                 if (!ret)
 915                         break;
 916                 ret = wait_for_rm_process();
 917                 if (ret < 0)
 918                         goto out;
 919         }
 920         for (;;) {
 921                 dss_get_snapshot_list(&sl);
 922                 ret = remove_redundant_snapshot(&sl);
 923                 free_snapshot_list(&sl);
 924                 if (ret < 0)
 925                         return ret;
 926                 if (!ret)
 927                         break;
 928                 ret = wait_for_rm_process();
 929                 if (ret < 0)
 930                         goto out;
 931         }
 932         return 1;
 933 out:
 934         return ret;
 935 }
 936
 937 static int com_create(void)
 938 {
 939         int ret, status;
 940         char **rsync_argv;
 941
 942         if (conf.dry_run_given) {
 943                 int i;
 944                 char *msg = NULL;
 945                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
 946                 for (i = 0; rsync_argv[i]; i++) {
 947                         char *tmp = msg;
 948                         msg = make_message("%s%s%s", tmp? tmp : "",
 949                                 tmp? " " : "", rsync_argv[i]);
 950                         free(tmp);
 951                 }
 952                 free_rsync_argv(rsync_argv);
 953                 dss_msg("%s\n", msg);
 954                 free(msg);
 955                 return 1;
 956         }
 957         ret = pre_create_hook();
 958         if (ret < 0)
 959                 return ret;
 960         if (pre_create_hook_pid) {
 961                 ret = wait_for_process(pre_create_hook_pid, &status);
 962                 if (ret < 0)
 963                         return ret;
 964                 ret = handle_pre_create_hook_exit(status);
 965                 if (ret < 0)
 966                         return ret;
 967         }
 968         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
 969         ret = create_snapshot(rsync_argv);
 970         if (ret < 0)
 971                 goto out;
 972         ret = wait_for_process(rsync_pid, &status);
 973         if (ret < 0)
 974                 goto out;
 975         ret = handle_rsync_exit(status);
 976         if (ret < 0)
 977                 goto out;
 978         post_create_hook();
 979         if (post_create_hook_pid)
 980                 ret = wait_for_process(post_create_hook_pid, &status);
 981 out:
 982         free_rsync_argv(rsync_argv);
 983         return ret;
 984 }
 985
 986 static int com_ls(void)
 987 {
 988         int i;
 989         struct snapshot_list sl;
 990         struct snapshot *s;
 991
 992         dss_get_snapshot_list(&sl);
 993         FOR_EACH_SNAPSHOT(s, i, &sl) {
 994                 int64_t d = 0;
 995                 if (s->flags & SS_COMPLETE)
 996                         d = (s->completion_time - s->creation_time) / 60;
 997                 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
 998         };
 999         free_snapshot_list(&sl);
1000         return 1;
1001 }
1002
1003 static int setup_signal_handling(void)
1004 {
1005         int ret;
1006
1007         DSS_INFO_LOG("setting up signal handlers\n");
1008         signal_pipe = signal_init(); /* always successful */
1009         ret = install_sighandler(SIGINT);
1010         if (ret < 0)
1011                 return ret;
1012         ret = install_sighandler(SIGTERM);
1013         if (ret < 0)
1014                 return ret;
1015         return install_sighandler(SIGCHLD);
1016 }
1017
1018 /**
1019  * The main function of dss.
1020  *
1021  * \param argc Usual argument count.
1022  * \param argv Usual argument vector.
1023  */
1024 int main(int argc, char **argv)
1025 {
1026         int ret;
1027         struct cmdline_parser_params params = {
1028                 .override = 0,
1029                 .initialize = 1,
1030                 .check_required = 0,
1031                 .check_ambiguity = 0,
1032                 .print_errors = 1
1033         };
1034
1035         cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1036         ret = parse_config_file(0);
1037         if (ret < 0)
1038                 goto out;
1039         if (conf.daemon_given)
1040                 daemon_init();
1041         ret = change_to_dest_dir();
1042         if (ret < 0)
1043                 goto out;
1044         ret = setup_signal_handling();
1045         if (ret < 0)
1046                 goto out;
1047         ret = call_command_handler();
1048 out:
1049         if (ret < 0)
1050                 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1051         exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1052 }