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