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, char *why)
 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 snapshot %s (interval = %i)\n",
 206                 why, s->name, s->interval);
 207         ret = dss_exec(&rm_pid, argv[0], argv, fds);
 208 out:
 209         free(new_name);
 210         return ret;
 211 }
 212
 213 static int snapshot_is_being_created(struct snapshot *s)
 214 {
 215         return s->creation_time == current_snapshot_creation_time;
 216 }
 217
 218 /*
 219  * return: 0: no redundant snapshots, 1: rm process started, negative: error
 220  */
 221 static int remove_redundant_snapshot(struct snapshot_list *sl)
 222 {
 223         int ret, i, interval;
 224         struct snapshot *s;
 225         unsigned missing = 0;
 226
 227         DSS_DEBUG_LOG("looking for intervals containing too many snapshots\n");
 228         for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
 229                 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
 230                 unsigned num = sl->interval_count[interval];
 231                 struct snapshot *victim = NULL, *prev = NULL;
 232                 int64_t score = LONG_MAX;
 233
 234                 if (keep >= num)
 235                         missing += keep - num;
 236 //              DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
 237 //                      interval, keep, num, missing);
 238                 if (keep + missing >= num)
 239                         continue;
 240                 /* redundant snapshot in this interval, pick snapshot with lowest score */
 241                 FOR_EACH_SNAPSHOT(s, i, sl) {
 242                         int64_t this_score;
 243
 244                         if (snapshot_is_being_created(s))
 245                                 continue;
 246                         //DSS_DEBUG_LOG("checking %s\n", s->name);
 247                         if (s->interval > interval) {
 248                                 prev = s;
 249                                 continue;
 250                         }
 251                         if (s->interval < interval)
 252                                 break;
 253                         if (!victim) {
 254                                 victim = s;
 255                                 prev = s;
 256                                 continue;
 257                         }
 258                         assert(prev);
 259                         /* check if s is a better victim */
 260                         this_score = s->creation_time - prev->creation_time;
 261                         assert(this_score >= 0);
 262                         //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
 263                         if (this_score < score) {
 264                                 score = this_score;
 265                                 victim = s;
 266                         }
 267                         prev = s;
 268                 }
 269                 assert(victim);
 270                 if (conf.dry_run_given) {
 271                         dss_msg("%s would be removed (interval = %i)\n",
 272                                 victim->name, victim->interval);
 273                         continue;
 274                 }
 275                 ret = remove_snapshot(victim, "redundant");
 276                 return ret < 0? ret : 1;
 277         }
 278         return 0;
 279 }
 280
 281 static int remove_outdated_snapshot(struct snapshot_list *sl)
 282 {
 283         int i, ret;
 284         struct snapshot *s;
 285
 286         DSS_DEBUG_LOG("looking for snapshots belonging to intervals greater than %d\n",
 287                 conf.num_intervals_arg);
 288         FOR_EACH_SNAPSHOT(s, i, sl) {
 289                 if (snapshot_is_being_created(s))
 290                         continue;
 291                 if (s->interval <= conf.num_intervals_arg)
 292                         continue;
 293                 if (conf.dry_run_given) {
 294                         dss_msg("%s would be removed (interval = %i)\n",
 295                                 s->name, s->interval);
 296                         continue;
 297                 }
 298                 ret = remove_snapshot(s, "outdated");
 299                 if (ret < 0)
 300                         return ret;
 301                 return 1;
 302         }
 303         return 0;
 304 }
 305
 306 static int remove_oldest_snapshot(struct snapshot_list *sl)
 307 {
 308         struct snapshot *s = get_oldest_snapshot(sl);
 309
 310         if (!s) /* no snapshot found */
 311                 return 0;
 312         DSS_INFO_LOG("oldest snapshot: %s\n", s->name);
 313         if (snapshot_is_being_created(s))
 314                 return 0;
 315         return remove_snapshot(s, "oldest");
 316 }
 317
 318 static int rename_incomplete_snapshot(int64_t start)
 319 {
 320         char *old_name;
 321         int ret;
 322
 323         free(path_to_last_complete_snapshot);
 324         ret = complete_name(start, get_current_time(),
 325                 &path_to_last_complete_snapshot);
 326         if (ret < 0)
 327                 return ret;
 328         old_name = incomplete_name(start);
 329         ret = dss_rename(old_name, path_to_last_complete_snapshot);
 330         if (ret >= 0)
 331                 DSS_NOTICE_LOG("%s -> %s\n", old_name,
 332                         path_to_last_complete_snapshot);
 333         free(old_name);
 334         return ret;
 335 }
 336
 337 static int try_to_free_disk_space(int low_disk_space)
 338 {
 339         int ret;
 340         struct snapshot_list sl;
 341
 342         if (!low_disk_space && conf.keep_redundant_given)
 343                 return 0;
 344         dss_get_snapshot_list(&sl);
 345         ret = remove_outdated_snapshot(&sl);
 346         if (ret) /* error, or we are removing something */
 347                 goto out;
 348         /* no outdated snapshot */
 349         ret = remove_redundant_snapshot(&sl);
 350         if (ret)
 351                 goto out;
 352         ret = 0;
 353         if (!low_disk_space)
 354                 goto out;
 355         DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
 356         ret = remove_oldest_snapshot(&sl);
 357         if (ret)
 358                 goto out;
 359         DSS_CRIT_LOG("uhuhu: not enough disk space for a single snapshot\n");
 360         ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
 361 out:
 362         free_snapshot_list(&sl);
 363         return ret;
 364 }
 365
 366 static int pre_create_hook(void)
 367 {
 368         int ret, fds[3] = {0, 0, 0};
 369
 370         if (!conf.pre_create_hook_given) {
 371                 snapshot_creation_status = SCS_PRE_HOOK_SUCCESS;
 372                 return 0;
 373         }
 374         DSS_NOTICE_LOG("executing %s\n", conf.pre_create_hook_arg);
 375         ret = dss_exec_cmdline_pid(&pre_create_hook_pid,
 376                 conf.pre_create_hook_arg, fds);
 377         if (ret < 0)
 378                 return ret;
 379         snapshot_creation_status = SCS_PRE_HOOK_RUNNING;
 380         return ret;
 381 }
 382
 383 static int post_create_hook(void)
 384 {
 385         int ret, fds[3] = {0, 0, 0};
 386         char *cmd;
 387
 388         if (!conf.post_create_hook_given) {
 389                 snapshot_creation_status = SCS_READY;
 390                 compute_next_snapshot_time();
 391                 return 0;
 392         }
 393         cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
 394                 conf.dest_dir_arg, path_to_last_complete_snapshot);
 395         DSS_NOTICE_LOG("executing %s\n", cmd);
 396         ret = dss_exec_cmdline_pid(&post_create_hook_pid, cmd, fds);
 397         free(cmd);
 398         if (ret < 0)
 399                 return ret;
 400         snapshot_creation_status = SCS_POST_HOOK_RUNNING;
 401         return ret;
 402 }
 403
 404 static void kill_process(pid_t pid)
 405 {
 406         if (!pid)
 407                 return;
 408         DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
 409         kill(pid, SIGTERM);
 410 }
 411
 412 static void stop_rsync_process(void)
 413 {
 414         if (!rsync_pid || rsync_stopped)
 415                 return;
 416         kill(SIGSTOP, rsync_pid);
 417         rsync_stopped = 1;
 418 }
 419
 420 static void restart_rsync_process(void)
 421 {
 422         if (!rsync_pid || !rsync_stopped)
 423                 return;
 424         kill (SIGCONT, rsync_pid);
 425         rsync_stopped = 0;
 426 }
 427
 428
 429 /**
 430  * Print a log message about the exit status of a child.
 431  */
 432 static void log_termination_msg(pid_t pid, int status)
 433 {
 434         if (WIFEXITED(status))
 435                 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
 436                         WEXITSTATUS(status));
 437         else if (WIFSIGNALED(status))
 438                 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
 439                         WTERMSIG(status));
 440         else
 441                 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
 442 }
 443
 444 static int wait_for_process(pid_t pid, int *status)
 445 {
 446         int ret;
 447
 448         DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
 449         for (;;) {
 450                 fd_set rfds;
 451
 452                 FD_ZERO(&rfds);
 453                 FD_SET(signal_pipe, &rfds);
 454                 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
 455                 if (ret < 0)
 456                         break;
 457                 ret = next_signal();
 458                 if (!ret)
 459                         continue;
 460                 if (ret == SIGCHLD) {
 461                         ret = waitpid(pid, status, 0);
 462                         if (ret >= 0)
 463                                 break;
 464                         if (errno != EINTR) { /* error */
 465                                 ret = -ERRNO_TO_DSS_ERROR(errno);
 466                                 break;
 467                         }
 468                 }
 469                 /* SIGINT or SIGTERM */
 470                 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
 471                 kill(pid, SIGTERM);
 472         }
 473         if (ret < 0)
 474                 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
 475         else
 476                 log_termination_msg(pid, *status);
 477         return ret;
 478 }
 479
 480 static int handle_rm_exit(int status)
 481 {
 482         rm_pid = 0;
 483         if (!WIFEXITED(status))
 484                 return -E_INVOLUNTARY_EXIT;
 485         if (WEXITSTATUS(status))
 486                 return -E_BAD_EXIT_CODE;
 487         return 1;
 488 }
 489
 490 static int wait_for_rm_process(void)
 491 {
 492         int status, ret = wait_for_process(rm_pid, &status);
 493
 494         if (ret < 0)
 495                 return ret;
 496         return handle_rm_exit(status);
 497 }
 498
 499 static int handle_rsync_exit(int status)
 500 {
 501         int es, ret;
 502
 503         if (!WIFEXITED(status)) {
 504                 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)rsync_pid);
 505                 ret = -E_INVOLUNTARY_EXIT;
 506                 snapshot_creation_status = SCS_READY;
 507                 compute_next_snapshot_time();
 508                 goto out;
 509         }
 510         es = WEXITSTATUS(status);
 511         if (es == 13) { /* Errors with program diagnostics */
 512                 DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
 513                         (int)rsync_pid, es);
 514                 snapshot_creation_status = SCS_RSYNC_NEEDS_RESTART;
 515                 gettimeofday(&next_snapshot_time, NULL);
 516                 next_snapshot_time.tv_sec += 60;
 517                 ret = 1;
 518                 goto out;
 519         }
 520         if (es != 0 && es != 23 && es != 24) {
 521                 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)rsync_pid, es);
 522                 ret = -E_BAD_EXIT_CODE;
 523                 snapshot_creation_status = SCS_READY;
 524                 compute_next_snapshot_time();
 525                 goto out;
 526         }
 527         ret = rename_incomplete_snapshot(current_snapshot_creation_time);
 528         if (ret < 0)
 529                 goto out;
 530         snapshot_creation_status = SCS_RSYNC_SUCCESS;
 531 out:
 532         rsync_pid = 0;
 533         rsync_stopped = 0;
 534         return ret;
 535 }
 536
 537 static int handle_pre_create_hook_exit(int status)
 538 {
 539         int es, ret;
 540
 541         if (!WIFEXITED(status)) {
 542                 snapshot_creation_status = SCS_READY;
 543                 compute_next_snapshot_time();
 544                 ret = -E_INVOLUNTARY_EXIT;
 545                 goto out;
 546         }
 547         es = WEXITSTATUS(status);
 548         if (es) {
 549                 snapshot_creation_status = SCS_READY;
 550                 compute_next_snapshot_time();
 551                 ret = -E_BAD_EXIT_CODE;
 552                 goto out;
 553         }
 554         snapshot_creation_status = SCS_PRE_HOOK_SUCCESS;
 555         ret = 1;
 556 out:
 557         pre_create_hook_pid = 0;
 558         return ret;
 559 }
 560
 561 static int handle_sigchld(void)
 562 {
 563         pid_t pid;
 564         int status, ret = reap_child(&pid, &status);
 565
 566         if (ret <= 0)
 567                 return ret;
 568         if (pid == rsync_pid)
 569                 return handle_rsync_exit(status);
 570         if (pid == rm_pid)
 571                 return handle_rm_exit(status);
 572         if (pid == pre_create_hook_pid)
 573                 return handle_pre_create_hook_exit(status);
 574         if (pid == post_create_hook_pid) {
 575                 snapshot_creation_status = SCS_READY;
 576                 compute_next_snapshot_time();
 577                 return 1;
 578         }
 579         DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
 580         return -E_BUG;
 581 }
 582
 583 static int check_config(void)
 584 {
 585         if (conf.unit_interval_arg <= 0) {
 586                 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
 587                 return -E_INVALID_NUMBER;
 588         }
 589         DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
 590         if (conf.num_intervals_arg <= 0) {
 591                 DSS_ERROR_LOG("bad number of intervals  %i\n", conf.num_intervals_arg);
 592                 return -E_INVALID_NUMBER;
 593         }
 594         DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
 595         return 1;
 596 }
 597
 598 static int parse_config_file(int override)
 599 {
 600         int ret;
 601         char *config_file;
 602         struct stat statbuf;
 603         char *old_logfile_arg = NULL;
 604         int old_daemon_given = 0;
 605
 606         if (conf.config_file_given)
 607                 config_file = dss_strdup(conf.config_file_arg);
 608         else {
 609                 char *home = get_homedir();
 610                 config_file = make_message("%s/.dssrc", home);
 611                 free(home);
 612         }
 613         if (override) { /* SIGHUP */
 614                 if (conf.logfile_given)
 615                         old_logfile_arg = dss_strdup(conf.logfile_arg);
 616                 old_daemon_given = conf.daemon_given;
 617         }
 618
 619         ret = stat(config_file, &statbuf);
 620         if (ret && conf.config_file_given) {
 621                 ret = -ERRNO_TO_DSS_ERROR(errno);
 622                 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
 623                 goto out;
 624         }
 625         if (!ret) {
 626                 struct cmdline_parser_params params = {
 627                         .override = override,
 628                         .initialize = 0,
 629                         .check_required = 1,
 630                         .check_ambiguity = 0,
 631                         .print_errors = 1
 632                 };
 633                 if (override) { /* invalidate all rsync options */
 634                         int i;
 635
 636                         for (i = 0; i < conf.rsync_option_given; i++) {
 637                                 free(conf.rsync_option_arg[i]);
 638                                 conf.rsync_option_arg[i] = NULL;
 639                         }
 640                         conf.rsync_option_given = 0;
 641                 }
 642                 cmdline_parser_config_file(config_file, &conf, &params);
 643         }
 644         ret = check_config();
 645         if (ret < 0)
 646                 goto out;
 647         if (override) {
 648                 /* don't change daemon mode on SIGHUP */
 649                 conf.daemon_given = old_daemon_given;
 650                 close_log(logfile);
 651                 logfile = NULL;
 652                 if (conf.logfile_given)
 653                         free(old_logfile_arg);
 654                 else if (conf.daemon_given) { /* re-use old logfile */
 655                         conf.logfile_arg = old_logfile_arg;
 656                         conf.logfile_given = 1;
 657                 }
 658         }
 659         if (conf.logfile_given) {
 660                 logfile = open_log(conf.logfile_arg);
 661                 log_welcome(conf.loglevel_arg);
 662         }
 663         DSS_DEBUG_LOG("loglevel: %d\n", conf.loglevel_arg);
 664 //      cmdline_parser_dump(logfile? logfile : stdout, &conf);
 665 out:
 666         free(config_file);
 667         if (ret < 0)
 668                 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
 669         return ret;
 670 }
 671
 672 static int change_to_dest_dir(void)
 673 {
 674         DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
 675         return dss_chdir(conf.dest_dir_arg);
 676 }
 677
 678 static int handle_sighup(void)
 679 {
 680         int ret;
 681
 682         DSS_NOTICE_LOG("SIGHUP\n");
 683         ret = parse_config_file(1);
 684         if (ret < 0)
 685                 return ret;
 686         return change_to_dest_dir();
 687 }
 688
 689 static int handle_signal(void)
 690 {
 691         int sig, ret = next_signal();
 692
 693         if (ret <= 0)
 694                 goto out;
 695         sig = ret;
 696         switch (sig) {
 697         case SIGINT:
 698         case SIGTERM:
 699                 restart_rsync_process();
 700                 kill_process(rsync_pid);
 701                 kill_process(rm_pid);
 702                 ret = -E_SIGNAL;
 703                 break;
 704         case SIGHUP:
 705                 ret = handle_sighup();
 706                 break;
 707         case SIGCHLD:
 708                 ret = handle_sigchld();
 709                 break;
 710         }
 711 out:
 712         if (ret < 0)
 713                 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
 714         return ret;
 715 }
 716
 717 /*
 718  * We can not use rsync locally if the local user is different from the remote
 719  * user or if the src dir is not on the local host (or both).
 720  */
 721 static int use_rsync_locally(char *logname)
 722 {
 723         char *h = conf.remote_host_arg;
 724
 725         if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
 726                 return 0;
 727         if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
 728                 return 0;
 729         return 1;
 730 }
 731
 732 static void create_rsync_argv(char ***argv, int64_t *num)
 733 {
 734         char *logname, *newest;
 735         int i = 0, j;
 736         struct snapshot_list sl;
 737
 738         dss_get_snapshot_list(&sl);
 739         newest = name_of_newest_complete_snapshot(&sl);
 740         free_snapshot_list(&sl);
 741
 742         *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
 743         (*argv)[i++] = dss_strdup("rsync");
 744         (*argv)[i++] = dss_strdup("-aq");
 745         (*argv)[i++] = dss_strdup("--delete");
 746         for (j = 0; j < conf.rsync_option_given; j++)
 747                 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
 748         if (newest) {
 749                 DSS_INFO_LOG("using %s as reference snapshot\n", newest);
 750                 (*argv)[i++] = make_message("--link-dest=../%s", newest);
 751                 free(newest);
 752         } else
 753                 DSS_INFO_LOG("no previous snapshot found\n");
 754         logname = dss_logname();
 755         if (use_rsync_locally(logname))
 756                 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
 757         else
 758                 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
 759                         conf.remote_user_arg : logname,
 760                         conf.remote_host_arg, conf.source_dir_arg);
 761         free(logname);
 762         *num = get_current_time();
 763         (*argv)[i++] = incomplete_name(*num);
 764         (*argv)[i++] = NULL;
 765         for (j = 0; j < i; j++)
 766                 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
 767 }
 768
 769 static void free_rsync_argv(char **argv)
 770 {
 771         int i;
 772
 773         if (!argv)
 774                 return;
 775         for (i = 0; argv[i]; i++)
 776                 free(argv[i]);
 777         free(argv);
 778 }
 779
 780 static int create_snapshot(char **argv)
 781 {
 782         int ret, fds[3] = {0, 0, 0};
 783         char *name;
 784
 785         name = incomplete_name(current_snapshot_creation_time);
 786         DSS_NOTICE_LOG("creating new snapshot %s\n", name);
 787         free(name);
 788         ret = dss_exec(&rsync_pid, argv[0], argv, fds);
 789         if (ret < 0)
 790                 return ret;
 791         snapshot_creation_status = SCS_RSYNC_RUNNING;
 792         return ret;
 793 }
 794
 795 static int select_loop(void)
 796 {
 797         int ret;
 798         /* check every 60 seconds for free disk space */
 799         struct timeval tv;
 800         char **rsync_argv = NULL;
 801
 802         for (;;) {
 803                 fd_set rfds;
 804                 int low_disk_space;
 805                 struct timeval now, *tvp;
 806
 807                 if (rm_pid)
 808                         tvp = NULL; /* sleep until rm process dies */
 809                 else { /* sleep one minute */
 810                         tv.tv_sec = 60;
 811                         tv.tv_usec = 0;
 812                         tvp = &tv;
 813                 }
 814                 FD_ZERO(&rfds);
 815                 FD_SET(signal_pipe, &rfds);
 816                 DSS_DEBUG_LOG("tvp: %p, tv_sec : %lu\n", tvp, (long unsigned) tv.tv_sec);
 817                 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
 818                 if (ret < 0)
 819                         goto out;
 820                 if (FD_ISSET(signal_pipe, &rfds)) {
 821                         ret = handle_signal();
 822                         if (ret < 0)
 823                                 goto out;
 824                 }
 825                 if (rm_pid)
 826                         continue;
 827                 ret = disk_space_low();
 828                 if (ret < 0)
 829                         goto out;
 830                 low_disk_space = ret;
 831                 ret = try_to_free_disk_space(low_disk_space);
 832                 if (ret < 0)
 833                         goto out;
 834                 if (rm_pid) {
 835                         stop_rsync_process();
 836                         continue;
 837                 }
 838                 restart_rsync_process();
 839                 gettimeofday(&now, NULL);
 840                 if (tv_diff(&next_snapshot_time, &now, NULL) > 0)
 841                         continue;
 842                 switch (snapshot_creation_status) {
 843                 case SCS_READY:
 844                         ret = pre_create_hook();
 845                         if (ret < 0)
 846                                 goto out;
 847                         continue;
 848                 case SCS_PRE_HOOK_RUNNING:
 849                         continue;
 850                 case SCS_RSYNC_NEEDS_RESTART:
 851                         ret = create_snapshot(rsync_argv);
 852                         if (ret < 0)
 853                                 goto out;
 854                         continue;
 855                 case SCS_PRE_HOOK_SUCCESS:
 856                         free_rsync_argv(rsync_argv);
 857                         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
 858                         ret = create_snapshot(rsync_argv);
 859                         if (ret < 0)
 860                                 goto out;
 861                         continue;
 862                 case SCS_RSYNC_RUNNING:
 863                         continue;
 864                 case SCS_RSYNC_SUCCESS:
 865                         ret = post_create_hook();
 866                         if (ret < 0)
 867                                 goto out;
 868                         continue;
 869                 case SCS_POST_HOOK_RUNNING:
 870                         continue;
 871                 }
 872         }
 873 out:
 874         return ret;
 875 }
 876
 877 static void exit_hook(int exit_code)
 878 {
 879         int fds[3] = {0, 0, 0};
 880         char *argv[] = {conf.exit_hook_arg, dss_strerror(-exit_code), NULL};
 881         pid_t pid;
 882
 883         if (!conf.exit_hook_given)
 884                 return;
 885         DSS_NOTICE_LOG("executing %s %s\n", argv[0], argv[1]);
 886         dss_exec(&pid, conf.exit_hook_arg, argv, fds);
 887 }
 888
 889 static int com_run(void)
 890 {
 891         int ret;
 892
 893         if (conf.dry_run_given) {
 894                 DSS_ERROR_LOG("dry_run not supported by this command\n");
 895                 return -E_SYNTAX;
 896         }
 897         ret = install_sighandler(SIGHUP);
 898         if (ret < 0)
 899                 return ret;
 900         compute_next_snapshot_time();
 901         ret = select_loop();
 902         if (ret >= 0) /* impossible */
 903                 ret = -E_BUG;
 904         exit_hook(ret);
 905         return ret;
 906 }
 907
 908 static int com_prune(void)
 909 {
 910         int ret;
 911         struct snapshot_list sl;
 912         struct disk_space ds;
 913
 914         ret = get_disk_space(".", &ds);
 915         if (ret < 0)
 916                 return ret;
 917         log_disk_space(&ds);
 918         for (;;) {
 919                 dss_get_snapshot_list(&sl);
 920                 ret = remove_outdated_snapshot(&sl);
 921                 free_snapshot_list(&sl);
 922                 if (ret < 0)
 923                         return ret;
 924                 if (!ret)
 925                         break;
 926                 ret = wait_for_rm_process();
 927                 if (ret < 0)
 928                         goto out;
 929         }
 930         for (;;) {
 931                 dss_get_snapshot_list(&sl);
 932                 ret = remove_redundant_snapshot(&sl);
 933                 free_snapshot_list(&sl);
 934                 if (ret < 0)
 935                         return ret;
 936                 if (!ret)
 937                         break;
 938                 ret = wait_for_rm_process();
 939                 if (ret < 0)
 940                         goto out;
 941         }
 942         return 1;
 943 out:
 944         return ret;
 945 }
 946
 947 static int com_create(void)
 948 {
 949         int ret, status;
 950         char **rsync_argv;
 951
 952         if (conf.dry_run_given) {
 953                 int i;
 954                 char *msg = NULL;
 955                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
 956                 for (i = 0; rsync_argv[i]; i++) {
 957                         char *tmp = msg;
 958                         msg = make_message("%s%s%s", tmp? tmp : "",
 959                                 tmp? " " : "", rsync_argv[i]);
 960                         free(tmp);
 961                 }
 962                 free_rsync_argv(rsync_argv);
 963                 dss_msg("%s\n", msg);
 964                 free(msg);
 965                 return 1;
 966         }
 967         ret = pre_create_hook();
 968         if (ret < 0)
 969                 return ret;
 970         if (pre_create_hook_pid) {
 971                 ret = wait_for_process(pre_create_hook_pid, &status);
 972                 if (ret < 0)
 973                         return ret;
 974                 ret = handle_pre_create_hook_exit(status);
 975                 if (ret < 0)
 976                         return ret;
 977         }
 978         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
 979         ret = create_snapshot(rsync_argv);
 980         if (ret < 0)
 981                 goto out;
 982         ret = wait_for_process(rsync_pid, &status);
 983         if (ret < 0)
 984                 goto out;
 985         ret = handle_rsync_exit(status);
 986         if (ret < 0)
 987                 goto out;
 988         post_create_hook();
 989         if (post_create_hook_pid)
 990                 ret = wait_for_process(post_create_hook_pid, &status);
 991 out:
 992         free_rsync_argv(rsync_argv);
 993         return ret;
 994 }
 995
 996 static int com_ls(void)
 997 {
 998         int i;
 999         struct snapshot_list sl;
1000         struct snapshot *s;
1001
1002         dss_get_snapshot_list(&sl);
1003         FOR_EACH_SNAPSHOT(s, i, &sl) {
1004                 int64_t d = 0;
1005                 if (s->flags & SS_COMPLETE)
1006                         d = (s->completion_time - s->creation_time) / 60;
1007                 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1008         };
1009         free_snapshot_list(&sl);
1010         return 1;
1011 }
1012
1013 static int setup_signal_handling(void)
1014 {
1015         int ret;
1016
1017         DSS_INFO_LOG("setting up signal handlers\n");
1018         signal_pipe = signal_init(); /* always successful */
1019         ret = install_sighandler(SIGINT);
1020         if (ret < 0)
1021                 return ret;
1022         ret = install_sighandler(SIGTERM);
1023         if (ret < 0)
1024                 return ret;
1025         return install_sighandler(SIGCHLD);
1026 }
1027
1028 /**
1029  * The main function of dss.
1030  *
1031  * \param argc Usual argument count.
1032  * \param argv Usual argument vector.
1033  */
1034 int main(int argc, char **argv)
1035 {
1036         int ret;
1037         struct cmdline_parser_params params = {
1038                 .override = 0,
1039                 .initialize = 1,
1040                 .check_required = 0,
1041                 .check_ambiguity = 0,
1042                 .print_errors = 1
1043         };
1044
1045         cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1046         ret = parse_config_file(0);
1047         if (ret < 0)
1048                 goto out;
1049         if (conf.daemon_given)
1050                 daemon_init();
1051         ret = change_to_dest_dir();
1052         if (ret < 0)
1053                 goto out;
1054         ret = setup_signal_handling();
1055         if (ret < 0)
1056                 goto out;
1057         ret = call_command_handler();
1058 out:
1059         if (ret < 0)
1060                 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1061         exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1062 }