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 static int snapshot_is_being_created(struct snapshot *s)
 213 {
 214         return s->creation_time == current_snapshot_creation_time;
 215 }
 216
 217 /*
 218  * return: 0: no redundant snapshots, 1: rm process started, negative: error
 219  */
 220 static int remove_redundant_snapshot(struct snapshot_list *sl)
 221 {
 222         int ret, i, interval;
 223         struct snapshot *s;
 224         unsigned missing = 0;
 225
 226         DSS_DEBUG_LOG("looking for intervals containing too many snapshots\n");
 227         for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
 228                 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
 229                 unsigned num = sl->interval_count[interval];
 230                 struct snapshot *victim = NULL, *prev = NULL;
 231                 int64_t score = LONG_MAX;
 232
 233                 if (keep >= num)
 234                         missing += keep - num;
 235 //              DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
 236 //                      interval, keep, num, missing);
 237                 if (keep + missing >= num)
 238                         continue;
 239                 /* redundant snapshot in this interval, pick snapshot with lowest score */
 240                 FOR_EACH_SNAPSHOT(s, i, sl) {
 241                         int64_t this_score;
 242
 243                         if (snapshot_is_being_created(s))
 244                                 continue;
 245                         //DSS_DEBUG_LOG("checking %s\n", s->name);
 246                         if (s->interval > interval) {
 247                                 prev = s;
 248                                 continue;
 249                         }
 250                         if (s->interval < interval)
 251                                 break;
 252                         if (!victim) {
 253                                 victim = s;
 254                                 prev = s;
 255                                 continue;
 256                         }
 257                         assert(prev);
 258                         /* check if s is a better victim */
 259                         this_score = s->creation_time - prev->creation_time;
 260                         assert(this_score >= 0);
 261                         //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
 262                         if (this_score < score) {
 263                                 score = this_score;
 264                                 victim = s;
 265                         }
 266                         prev = s;
 267                 }
 268                 assert(victim);
 269                 if (conf.dry_run_given) {
 270                         dss_msg("%s would be removed (interval = %i)\n",
 271                                 victim->name, victim->interval);
 272                         continue;
 273                 }
 274                 ret = remove_snapshot(victim);
 275                 return ret < 0? ret : 1;
 276         }
 277         return 0;
 278 }
 279
 280 static int remove_outdated_snapshot(struct snapshot_list *sl)
 281 {
 282         int i, ret;
 283         struct snapshot *s;
 284
 285         DSS_DEBUG_LOG("looking for snapshots belonging to intervals greater than %d\n",
 286                 conf.num_intervals_arg);
 287         FOR_EACH_SNAPSHOT(s, i, sl) {
 288                 if (snapshot_is_being_created(s))
 289                         continue;
 290                 if (s->interval <= conf.num_intervals_arg)
 291                         continue;
 292                 if (conf.dry_run_given) {
 293                         dss_msg("%s would be removed (interval = %i)\n",
 294                                 s->name, s->interval);
 295                         continue;
 296                 }
 297                 ret = remove_snapshot(s);
 298                 if (ret < 0)
 299                         return ret;
 300                 return 1;
 301         }
 302         return 0;
 303 }
 304
 305 static int remove_oldest_snapshot(struct snapshot_list *sl)
 306 {
 307         struct snapshot *s = get_oldest_snapshot(sl);
 308
 309         if (!s) /* no snapshot found */
 310                 return 0;
 311         DSS_INFO_LOG("oldest snapshot: %s\n", s->name);
 312         if (snapshot_is_being_created(s))
 313                 return 0;
 314         return remove_snapshot(s);
 315 }
 316
 317 static int rename_incomplete_snapshot(int64_t start)
 318 {
 319         char *old_name;
 320         int ret;
 321
 322         free(path_to_last_complete_snapshot);
 323         ret = complete_name(start, get_current_time(),
 324                 &path_to_last_complete_snapshot);
 325         if (ret < 0)
 326                 return ret;
 327         old_name = incomplete_name(start);
 328         ret = dss_rename(old_name, path_to_last_complete_snapshot);
 329         if (ret >= 0)
 330                 DSS_NOTICE_LOG("%s -> %s\n", old_name,
 331                         path_to_last_complete_snapshot);
 332         free(old_name);
 333         return ret;
 334 }
 335
 336 static int try_to_free_disk_space(int low_disk_space)
 337 {
 338         int ret;
 339         struct snapshot_list sl;
 340
 341         if (!low_disk_space && conf.keep_redundant_given)
 342                 return 0;
 343         dss_get_snapshot_list(&sl);
 344         ret = remove_outdated_snapshot(&sl);
 345         if (ret) /* error, or we are removing something */
 346                 goto out;
 347         /* no outdated snapshot */
 348         ret = remove_redundant_snapshot(&sl);
 349         if (ret)
 350                 goto out;
 351         ret = 0;
 352         if (!low_disk_space)
 353                 goto out;
 354         DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
 355         ret = remove_oldest_snapshot(&sl);
 356         if (ret)
 357                 goto out;
 358         DSS_CRIT_LOG("uhuhu: not enough disk space for a single snapshot\n");
 359         ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
 360 out:
 361         free_snapshot_list(&sl);
 362         return ret;
 363 }
 364
 365 static int pre_create_hook(void)
 366 {
 367         int ret, fds[3] = {0, 0, 0};
 368
 369         if (!conf.pre_create_hook_given) {
 370                 snapshot_creation_status = SCS_PRE_HOOK_SUCCESS;
 371                 return 0;
 372         }
 373         DSS_NOTICE_LOG("executing %s\n", conf.pre_create_hook_arg);
 374         ret = dss_exec_cmdline_pid(&pre_create_hook_pid,
 375                 conf.pre_create_hook_arg, fds);
 376         if (ret < 0)
 377                 return ret;
 378         snapshot_creation_status = SCS_PRE_HOOK_RUNNING;
 379         return ret;
 380 }
 381
 382 static int post_create_hook(void)
 383 {
 384         int ret, fds[3] = {0, 0, 0};
 385         char *cmd;
 386
 387         if (!conf.post_create_hook_given) {
 388                 snapshot_creation_status = SCS_READY;
 389                 compute_next_snapshot_time();
 390                 return 0;
 391         }
 392         cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
 393                 conf.dest_dir_arg, path_to_last_complete_snapshot);
 394         DSS_NOTICE_LOG("executing %s\n", cmd);
 395         ret = dss_exec_cmdline_pid(&post_create_hook_pid, cmd, fds);
 396         free(cmd);
 397         if (ret < 0)
 398                 return ret;
 399         snapshot_creation_status = SCS_POST_HOOK_RUNNING;
 400         return ret;
 401 }
 402
 403 static void kill_process(pid_t pid)
 404 {
 405         if (!pid)
 406                 return;
 407         DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
 408         kill(pid, SIGTERM);
 409 }
 410
 411 static void stop_rsync_process(void)
 412 {
 413         if (!rsync_pid || rsync_stopped)
 414                 return;
 415         kill(SIGSTOP, rsync_pid);
 416         rsync_stopped = 1;
 417 }
 418
 419 static void restart_rsync_process(void)
 420 {
 421         if (!rsync_pid || !rsync_stopped)
 422                 return;
 423         kill (SIGCONT, rsync_pid);
 424         rsync_stopped = 0;
 425 }
 426
 427
 428 /**
 429  * Print a log message about the exit status of a child.
 430  */
 431 static void log_termination_msg(pid_t pid, int status)
 432 {
 433         if (WIFEXITED(status))
 434                 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
 435                         WEXITSTATUS(status));
 436         else if (WIFSIGNALED(status))
 437                 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
 438                         WTERMSIG(status));
 439         else
 440                 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
 441 }
 442
 443 static int wait_for_process(pid_t pid, int *status)
 444 {
 445         int ret;
 446
 447         DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
 448         for (;;) {
 449                 fd_set rfds;
 450
 451                 FD_ZERO(&rfds);
 452                 FD_SET(signal_pipe, &rfds);
 453                 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
 454                 if (ret < 0)
 455                         break;
 456                 ret = next_signal();
 457                 if (!ret)
 458                         continue;
 459                 if (ret == SIGCHLD) {
 460                         ret = waitpid(pid, status, 0);
 461                         if (ret >= 0)
 462                                 break;
 463                         if (errno != EINTR) { /* error */
 464                                 ret = -ERRNO_TO_DSS_ERROR(errno);
 465                                 break;
 466                         }
 467                 }
 468                 /* SIGINT or SIGTERM */
 469                 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
 470                 kill(pid, SIGTERM);
 471         }
 472         if (ret < 0)
 473                 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
 474         else
 475                 log_termination_msg(pid, *status);
 476         return ret;
 477 }
 478
 479 static int handle_rm_exit(int status)
 480 {
 481         rm_pid = 0;
 482         if (!WIFEXITED(status))
 483                 return -E_INVOLUNTARY_EXIT;
 484         if (WEXITSTATUS(status))
 485                 return -E_BAD_EXIT_CODE;
 486         return 1;
 487 }
 488
 489 static int wait_for_rm_process(void)
 490 {
 491         int status, ret = wait_for_process(rm_pid, &status);
 492
 493         if (ret < 0)
 494                 return ret;
 495         return handle_rm_exit(status);
 496 }
 497
 498 static int handle_rsync_exit(int status)
 499 {
 500         int es, ret;
 501
 502         if (!WIFEXITED(status)) {
 503                 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)rsync_pid);
 504                 ret = -E_INVOLUNTARY_EXIT;
 505                 snapshot_creation_status = SCS_READY;
 506                 compute_next_snapshot_time();
 507                 goto out;
 508         }
 509         es = WEXITSTATUS(status);
 510         if (es == 13) { /* Errors with program diagnostics */
 511                 DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
 512                         (int)rsync_pid, es);
 513                 snapshot_creation_status = SCS_RSYNC_NEEDS_RESTART;
 514                 gettimeofday(&next_snapshot_time, NULL);
 515                 next_snapshot_time.tv_sec += 60;
 516                 ret = 1;
 517                 goto out;
 518         }
 519         if (es != 0 && es != 23 && es != 24) {
 520                 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)rsync_pid, es);
 521                 ret = -E_BAD_EXIT_CODE;
 522                 snapshot_creation_status = SCS_READY;
 523                 compute_next_snapshot_time();
 524                 goto out;
 525         }
 526         ret = rename_incomplete_snapshot(current_snapshot_creation_time);
 527         if (ret < 0)
 528                 goto out;
 529         snapshot_creation_status = SCS_RSYNC_SUCCESS;
 530 out:
 531         rsync_pid = 0;
 532         rsync_stopped = 0;
 533         return ret;
 534 }
 535
 536 static int handle_pre_create_hook_exit(int status)
 537 {
 538         int es, ret;
 539
 540         if (!WIFEXITED(status)) {
 541                 snapshot_creation_status = SCS_READY;
 542                 compute_next_snapshot_time();
 543                 ret = -E_INVOLUNTARY_EXIT;
 544                 goto out;
 545         }
 546         es = WEXITSTATUS(status);
 547         if (es) {
 548                 snapshot_creation_status = SCS_READY;
 549                 compute_next_snapshot_time();
 550                 ret = -E_BAD_EXIT_CODE;
 551                 goto out;
 552         }
 553         snapshot_creation_status = SCS_PRE_HOOK_SUCCESS;
 554         ret = 1;
 555 out:
 556         pre_create_hook_pid = 0;
 557         return ret;
 558 }
 559
 560 static int handle_sigchld(void)
 561 {
 562         pid_t pid;
 563         int status, ret = reap_child(&pid, &status);
 564
 565         if (ret <= 0)
 566                 return ret;
 567         if (pid == rsync_pid)
 568                 return handle_rsync_exit(status);
 569         if (pid == rm_pid)
 570                 return handle_rm_exit(status);
 571         if (pid == pre_create_hook_pid)
 572                 return handle_pre_create_hook_exit(status);
 573         if (pid == post_create_hook_pid) {
 574                 snapshot_creation_status = SCS_READY;
 575                 compute_next_snapshot_time();
 576                 return 1;
 577         }
 578         DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
 579         return -E_BUG;
 580 }
 581
 582 static int check_config(void)
 583 {
 584         if (conf.unit_interval_arg <= 0) {
 585                 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
 586                 return -E_INVALID_NUMBER;
 587         }
 588         DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
 589         if (conf.num_intervals_arg <= 0) {
 590                 DSS_ERROR_LOG("bad number of intervals  %i\n", conf.num_intervals_arg);
 591                 return -E_INVALID_NUMBER;
 592         }
 593         DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
 594         return 1;
 595 }
 596
 597 static int parse_config_file(int override)
 598 {
 599         int ret;
 600         char *config_file;
 601         struct stat statbuf;
 602         char *old_logfile_arg = NULL;
 603         int old_daemon_given = 0;
 604
 605         if (conf.config_file_given)
 606                 config_file = dss_strdup(conf.config_file_arg);
 607         else {
 608                 char *home = get_homedir();
 609                 config_file = make_message("%s/.dssrc", home);
 610                 free(home);
 611         }
 612         if (override) { /* SIGHUP */
 613                 if (conf.logfile_given)
 614                         old_logfile_arg = dss_strdup(conf.logfile_arg);
 615                 old_daemon_given = conf.daemon_given;
 616         }
 617
 618         ret = stat(config_file, &statbuf);
 619         if (ret && conf.config_file_given) {
 620                 ret = -ERRNO_TO_DSS_ERROR(errno);
 621                 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
 622                 goto out;
 623         }
 624         if (!ret) {
 625                 struct cmdline_parser_params params = {
 626                         .override = override,
 627                         .initialize = 0,
 628                         .check_required = 1,
 629                         .check_ambiguity = 0,
 630                         .print_errors = 1
 631                 };
 632                 if (override) { /* invalidate all rsync options */
 633                         int i;
 634
 635                         for (i = 0; i < conf.rsync_option_given; i++) {
 636                                 free(conf.rsync_option_arg[i]);
 637                                 conf.rsync_option_arg[i] = NULL;
 638                         }
 639                         conf.rsync_option_given = 0;
 640                 }
 641                 cmdline_parser_config_file(config_file, &conf, &params);
 642         }
 643         ret = check_config();
 644         if (ret < 0)
 645                 goto out;
 646         if (override) {
 647                 /* don't change daemon mode on SIGHUP */
 648                 conf.daemon_given = old_daemon_given;
 649                 close_log(logfile);
 650                 logfile = NULL;
 651                 if (conf.logfile_given)
 652                         free(old_logfile_arg);
 653                 else if (conf.daemon_given) { /* re-use old logfile */
 654                         conf.logfile_arg = old_logfile_arg;
 655                         conf.logfile_given = 1;
 656                 }
 657         }
 658         if (conf.logfile_given) {
 659                 logfile = open_log(conf.logfile_arg);
 660                 log_welcome(conf.loglevel_arg);
 661         }
 662         DSS_DEBUG_LOG("loglevel: %d\n", conf.loglevel_arg);
 663 //      cmdline_parser_dump(logfile? logfile : stdout, &conf);
 664 out:
 665         free(config_file);
 666         if (ret < 0)
 667                 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
 668         return ret;
 669 }
 670
 671 static int change_to_dest_dir(void)
 672 {
 673         DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
 674         return dss_chdir(conf.dest_dir_arg);
 675 }
 676
 677 static int handle_sighup(void)
 678 {
 679         int ret;
 680
 681         DSS_NOTICE_LOG("SIGHUP\n");
 682         ret = parse_config_file(1);
 683         if (ret < 0)
 684                 return ret;
 685         return change_to_dest_dir();
 686 }
 687
 688 static int handle_signal(void)
 689 {
 690         int sig, ret = next_signal();
 691
 692         if (ret <= 0)
 693                 goto out;
 694         sig = ret;
 695         switch (sig) {
 696         case SIGINT:
 697         case SIGTERM:
 698                 restart_rsync_process();
 699                 kill_process(rsync_pid);
 700                 kill_process(rm_pid);
 701                 ret = -E_SIGNAL;
 702                 break;
 703         case SIGHUP:
 704                 ret = handle_sighup();
 705                 break;
 706         case SIGCHLD:
 707                 ret = handle_sigchld();
 708                 break;
 709         }
 710 out:
 711         if (ret < 0)
 712                 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
 713         return ret;
 714 }
 715
 716 /*
 717  * We can not use rsync locally if the local user is different from the remote
 718  * user or if the src dir is not on the local host (or both).
 719  */
 720 static int use_rsync_locally(char *logname)
 721 {
 722         char *h = conf.remote_host_arg;
 723
 724         if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
 725                 return 0;
 726         if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
 727                 return 0;
 728         return 1;
 729 }
 730
 731 static void create_rsync_argv(char ***argv, int64_t *num)
 732 {
 733         char *logname, *newest;
 734         int i = 0, j;
 735         struct snapshot_list sl;
 736
 737         dss_get_snapshot_list(&sl);
 738         newest = name_of_newest_complete_snapshot(&sl);
 739         free_snapshot_list(&sl);
 740
 741         *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
 742         (*argv)[i++] = dss_strdup("rsync");
 743         (*argv)[i++] = dss_strdup("-aq");
 744         (*argv)[i++] = dss_strdup("--delete");
 745         for (j = 0; j < conf.rsync_option_given; j++)
 746                 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
 747         if (newest) {
 748                 DSS_INFO_LOG("using %s as reference snapshot\n", newest);
 749                 (*argv)[i++] = make_message("--link-dest=../%s", newest);
 750                 free(newest);
 751         } else
 752                 DSS_INFO_LOG("no previous snapshot found\n");
 753         logname = dss_logname();
 754         if (use_rsync_locally(logname))
 755                 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
 756         else
 757                 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
 758                         conf.remote_user_arg : logname,
 759                         conf.remote_host_arg, conf.source_dir_arg);
 760         free(logname);
 761         *num = get_current_time();
 762         (*argv)[i++] = incomplete_name(*num);
 763         (*argv)[i++] = NULL;
 764         for (j = 0; j < i; j++)
 765                 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
 766 }
 767
 768 static void free_rsync_argv(char **argv)
 769 {
 770         int i;
 771
 772         if (!argv)
 773                 return;
 774         for (i = 0; argv[i]; i++)
 775                 free(argv[i]);
 776         free(argv);
 777 }
 778
 779 static int create_snapshot(char **argv)
 780 {
 781         int ret, fds[3] = {0, 0, 0};
 782         char *name;
 783
 784         name = incomplete_name(current_snapshot_creation_time);
 785         DSS_NOTICE_LOG("creating new snapshot %s\n", name);
 786         free(name);
 787         ret = dss_exec(&rsync_pid, argv[0], argv, fds);
 788         if (ret < 0)
 789                 return ret;
 790         snapshot_creation_status = SCS_RSYNC_RUNNING;
 791         return ret;
 792 }
 793
 794 static int select_loop(void)
 795 {
 796         int ret;
 797         /* check every 60 seconds for free disk space */
 798         struct timeval tv;
 799         char **rsync_argv = NULL;
 800
 801         for (;;) {
 802                 fd_set rfds;
 803                 int low_disk_space;
 804                 struct timeval now, *tvp;
 805
 806                 if (rm_pid)
 807                         tvp = NULL; /* sleep until rm process dies */
 808                 else { /* sleep one minute */
 809                         tv.tv_sec = 60;
 810                         tv.tv_usec = 0;
 811                         tvp = &tv;
 812                 }
 813                 FD_ZERO(&rfds);
 814                 FD_SET(signal_pipe, &rfds);
 815                 DSS_DEBUG_LOG("tvp: %p, tv_sec : %lu\n", tvp, (long unsigned) tv.tv_sec);
 816                 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
 817                 if (ret < 0)
 818                         goto out;
 819                 if (FD_ISSET(signal_pipe, &rfds)) {
 820                         ret = handle_signal();
 821                         if (ret < 0)
 822                                 goto out;
 823                 }
 824                 if (rm_pid)
 825                         continue;
 826                 ret = disk_space_low();
 827                 if (ret < 0)
 828                         goto out;
 829                 low_disk_space = ret;
 830                 ret = try_to_free_disk_space(low_disk_space);
 831                 if (ret < 0)
 832                         goto out;
 833                 if (rm_pid) {
 834                         stop_rsync_process();
 835                         continue;
 836                 }
 837                 restart_rsync_process();
 838                 gettimeofday(&now, NULL);
 839                 if (tv_diff(&next_snapshot_time, &now, NULL) > 0)
 840                         continue;
 841                 switch (snapshot_creation_status) {
 842                 case SCS_READY:
 843                         ret = pre_create_hook();
 844                         if (ret < 0)
 845                                 goto out;
 846                         continue;
 847                 case SCS_PRE_HOOK_RUNNING:
 848                         continue;
 849                 case SCS_RSYNC_NEEDS_RESTART:
 850                         ret = create_snapshot(rsync_argv);
 851                         if (ret < 0)
 852                                 goto out;
 853                         continue;
 854                 case SCS_PRE_HOOK_SUCCESS:
 855                         free_rsync_argv(rsync_argv);
 856                         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
 857                         ret = create_snapshot(rsync_argv);
 858                         if (ret < 0)
 859                                 goto out;
 860                         continue;
 861                 case SCS_RSYNC_RUNNING:
 862                         continue;
 863                 case SCS_RSYNC_SUCCESS:
 864                         ret = post_create_hook();
 865                         if (ret < 0)
 866                                 goto out;
 867                         continue;
 868                 case SCS_POST_HOOK_RUNNING:
 869                         continue;
 870                 }
 871         }
 872 out:
 873         return ret;
 874 }
 875
 876 static void exit_hook(int exit_code)
 877 {
 878         int fds[3] = {0, 0, 0};
 879         char *argv[] = {conf.exit_hook_arg, dss_strerror(-exit_code), NULL};
 880         pid_t pid;
 881
 882         if (!conf.exit_hook_given)
 883                 return;
 884         DSS_NOTICE_LOG("executing %s %s\n", argv[0], argv[1]);
 885         dss_exec(&pid, conf.exit_hook_arg, argv, fds);
 886 }
 887
 888 static int com_run(void)
 889 {
 890         int ret;
 891
 892         if (conf.dry_run_given) {
 893                 DSS_ERROR_LOG("dry_run not supported by this command\n");
 894                 return -E_SYNTAX;
 895         }
 896         ret = install_sighandler(SIGHUP);
 897         if (ret < 0)
 898                 return ret;
 899         compute_next_snapshot_time();
 900         ret = select_loop();
 901         if (ret >= 0) /* impossible */
 902                 ret = -E_BUG;
 903         exit_hook(ret);
 904         return ret;
 905 }
 906
 907 static int com_prune(void)
 908 {
 909         int ret;
 910         struct snapshot_list sl;
 911         struct disk_space ds;
 912
 913         ret = get_disk_space(".", &ds);
 914         if (ret < 0)
 915                 return ret;
 916         log_disk_space(&ds);
 917         for (;;) {
 918                 dss_get_snapshot_list(&sl);
 919                 ret = remove_outdated_snapshot(&sl);
 920                 free_snapshot_list(&sl);
 921                 if (ret < 0)
 922                         return ret;
 923                 if (!ret)
 924                         break;
 925                 ret = wait_for_rm_process();
 926                 if (ret < 0)
 927                         goto out;
 928         }
 929         for (;;) {
 930                 dss_get_snapshot_list(&sl);
 931                 ret = remove_redundant_snapshot(&sl);
 932                 free_snapshot_list(&sl);
 933                 if (ret < 0)
 934                         return ret;
 935                 if (!ret)
 936                         break;
 937                 ret = wait_for_rm_process();
 938                 if (ret < 0)
 939                         goto out;
 940         }
 941         return 1;
 942 out:
 943         return ret;
 944 }
 945
 946 static int com_create(void)
 947 {
 948         int ret, status;
 949         char **rsync_argv;
 950
 951         if (conf.dry_run_given) {
 952                 int i;
 953                 char *msg = NULL;
 954                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
 955                 for (i = 0; rsync_argv[i]; i++) {
 956                         char *tmp = msg;
 957                         msg = make_message("%s%s%s", tmp? tmp : "",
 958                                 tmp? " " : "", rsync_argv[i]);
 959                         free(tmp);
 960                 }
 961                 free_rsync_argv(rsync_argv);
 962                 dss_msg("%s\n", msg);
 963                 free(msg);
 964                 return 1;
 965         }
 966         ret = pre_create_hook();
 967         if (ret < 0)
 968                 return ret;
 969         if (pre_create_hook_pid) {
 970                 ret = wait_for_process(pre_create_hook_pid, &status);
 971                 if (ret < 0)
 972                         return ret;
 973                 ret = handle_pre_create_hook_exit(status);
 974                 if (ret < 0)
 975                         return ret;
 976         }
 977         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
 978         ret = create_snapshot(rsync_argv);
 979         if (ret < 0)
 980                 goto out;
 981         ret = wait_for_process(rsync_pid, &status);
 982         if (ret < 0)
 983                 goto out;
 984         ret = handle_rsync_exit(status);
 985         if (ret < 0)
 986                 goto out;
 987         post_create_hook();
 988         if (post_create_hook_pid)
 989                 ret = wait_for_process(post_create_hook_pid, &status);
 990 out:
 991         free_rsync_argv(rsync_argv);
 992         return ret;
 993 }
 994
 995 static int com_ls(void)
 996 {
 997         int i;
 998         struct snapshot_list sl;
 999         struct snapshot *s;
1000
1001         dss_get_snapshot_list(&sl);
1002         FOR_EACH_SNAPSHOT(s, i, &sl) {
1003                 int64_t d = 0;
1004                 if (s->flags & SS_COMPLETE)
1005                         d = (s->completion_time - s->creation_time) / 60;
1006                 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1007         };
1008         free_snapshot_list(&sl);
1009         return 1;
1010 }
1011
1012 static int setup_signal_handling(void)
1013 {
1014         int ret;
1015
1016         DSS_INFO_LOG("setting up signal handlers\n");
1017         signal_pipe = signal_init(); /* always successful */
1018         ret = install_sighandler(SIGINT);
1019         if (ret < 0)
1020                 return ret;
1021         ret = install_sighandler(SIGTERM);
1022         if (ret < 0)
1023                 return ret;
1024         return install_sighandler(SIGCHLD);
1025 }
1026
1027 /**
1028  * The main function of dss.
1029  *
1030  * \param argc Usual argument count.
1031  * \param argv Usual argument vector.
1032  */
1033 int main(int argc, char **argv)
1034 {
1035         int ret;
1036         struct cmdline_parser_params params = {
1037                 .override = 0,
1038                 .initialize = 1,
1039                 .check_required = 0,
1040                 .check_ambiguity = 0,
1041                 .print_errors = 1
1042         };
1043
1044         cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1045         ret = parse_config_file(0);
1046         if (ret < 0)
1047                 goto out;
1048         if (conf.daemon_given)
1049                 daemon_init();
1050         ret = change_to_dest_dir();
1051         if (ret < 0)
1052                 goto out;
1053         ret = setup_signal_handling();
1054         if (ret < 0)
1055                 goto out;
1056         ret = call_command_handler();
1057 out:
1058         if (ret < 0)
1059                 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1060         exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1061 }