dss.c

   1 #include <string.h>
   2 #include <stdlib.h>
   3 #include <stdarg.h>
   4 #include <assert.h>
   5 #include <errno.h>
   6 #include <sys/types.h>
   7 #include <signal.h>
   8 #include <ctype.h>
   9 #include <sys/stat.h>
  10 #include <unistd.h>
  11 #include <inttypes.h>
  12 #include <sys/time.h>
  13 #include <time.h>
  14 #include <sys/wait.h>
  15 #include <fnmatch.h>
  16 #include <limits.h>
  17
  18
  19 #include "gcc-compat.h"
  20 #include "cmdline.h"
  21 #include "log.h"
  22 #include "string.h"
  23 #include "error.h"
  24 #include "fd.h"
  25 #include "exec.h"
  26 #include "daemon.h"
  27 #include "signal.h"
  28 #include "df.h"
  29 #include "time.h"
  30
  31
  32 struct gengetopt_args_info conf;
  33 char *dss_error_txt = NULL;
  34 static FILE *logfile;
  35 static int signal_pipe;
  36
  37 /** Process id of current rsync process. */
  38 static pid_t rsync_pid;
  39 /** Whether the rsync process is currently stopped */
  40 static int rsync_stopped;
  41 /** Process id of current rm process. */
  42 static pid_t rm_pid;
  43 /** When the next snapshot is due. */
  44 struct timeval next_snapshot_time;
  45 /* Creation time of the snapshot currently being created. */
  46 int64_t current_snapshot_creation_time;
  47
  48
  49 DEFINE_DSS_ERRLIST;
  50
  51
  52 /* a litte cpp magic helps to DRY */
  53 #define COMMANDS \
  54         COMMAND(ls) \
  55         COMMAND(create) \
  56         COMMAND(prune) \
  57         COMMAND(run)
  58 #define COMMAND(x) int com_ ##x(void);
  59 COMMANDS
  60 #undef COMMAND
  61 #define COMMAND(x) if (conf.x ##_given) return com_ ##x();
  62 int call_command_handler(void)
  63 {
  64         COMMANDS
  65         DSS_EMERG_LOG("BUG: did not find command handler\n");
  66         exit(EXIT_FAILURE);
  67 }
  68 #undef COMMAND
  69 #undef COMMANDS
  70
  71 /*
  72  * complete, not being deleted: 1204565370-1204565371.Sun_Mar_02_2008_14_33-Sun_Mar_02_2008_14_43
  73  * complete, being deleted: 1204565370-1204565371.being_deleted
  74  * incomplete, not being deleted: 1204565370-incomplete
  75  * incomplete, being deleted: 1204565370-incomplete.being_deleted
  76  */
  77 enum snapshot_status_flags {
  78         /** The rsync process terminated successfully. */
  79         SS_COMPLETE = 1,
  80         /** The rm process is running to remove this snapshot. */
  81         SS_BEING_DELETED = 2,
  82 };
  83
  84 struct snapshot {
  85         char *name;
  86         int64_t creation_time;
  87         int64_t completion_time;
  88         enum snapshot_status_flags flags;
  89         unsigned interval;
  90 };
  91
  92 /*
  93  * An edge snapshot is either the oldest one or the newest one.
  94  *
  95  * We need to find either of them occasionally: The create code
  96  * needs to know the newest snapshot because that is the one
  97  * used as the link destination dir. The pruning code needs to
  98  * find the oldest one in case disk space becomes low.
  99  */
 100 struct edge_snapshot_data {
 101         int64_t now;
 102         struct snapshot snap;
 103 };
 104
 105 __printf_2_3 void dss_log(int ll, const char* fmt,...)
 106 {
 107         va_list argp;
 108         FILE *outfd;
 109         struct tm *tm;
 110         time_t t1;
 111         char str[255] = "";
 112
 113         if (ll < conf.loglevel_arg)
 114                 return;
 115         outfd = logfile? logfile : stderr;
 116         time(&t1);
 117         tm = localtime(&t1);
 118         strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
 119         fprintf(outfd, "%s ", str);
 120         if (conf.loglevel_arg <= INFO)
 121                 fprintf(outfd, "%i: ", ll);
 122         va_start(argp, fmt);
 123         vfprintf(outfd, fmt, argp);
 124         va_end(argp);
 125 }
 126
 127 /**
 128  * Print a message either to stdout or to the log file.
 129  */
 130 __printf_1_2 void dss_msg(const char* fmt,...)
 131 {
 132         FILE *outfd = conf.daemon_given? logfile : stdout;
 133         va_list argp;
 134         va_start(argp, fmt);
 135         vfprintf(outfd, fmt, argp);
 136         va_end(argp);
 137 }
 138
 139 /**
 140  * Return the desired number of snapshots of an interval.
 141  */
 142 unsigned num_snapshots(int interval)
 143 {
 144         unsigned n;
 145
 146         assert(interval >= 0);
 147
 148         if (interval >= conf.num_intervals_arg)
 149                 return 0;
 150         n = conf.num_intervals_arg - interval - 1;
 151         return 1 << n;
 152 }
 153
 154 /* return: Whether dirname is a snapshot directory (0: no, 1: yes) */
 155 int is_snapshot(const char *dirname, int64_t now, struct snapshot *s)
 156 {
 157         int i, ret;
 158         char *dash, *dot, *tmp;
 159         int64_t num;
 160
 161         assert(dirname);
 162         dash = strchr(dirname, '-');
 163         if (!dash || !dash[1] || dash == dirname)
 164                 return 0;
 165         for (i = 0; dirname[i] != '-'; i++)
 166                 if (!isdigit(dirname[i]))
 167                         return 0;
 168         tmp = dss_strdup(dirname);
 169         tmp[i] = '\0';
 170         ret = dss_atoi64(tmp, &num);
 171         free(tmp);
 172         if (ret < 0) {
 173                 free(dss_error_txt);
 174                 return 0;
 175         }
 176         assert(num >= 0);
 177         if (num > now)
 178                 return 0;
 179         s->creation_time = num;
 180         //DSS_DEBUG_LOG("%s start time: %lli\n", dirname, (long long)s->creation_time);
 181         s->interval = (long long) ((now - s->creation_time)
 182                 / conf.unit_interval_arg / 24 / 3600);
 183         if (!strcmp(dash + 1, "incomplete")) {
 184                 s->completion_time = -1;
 185                 s->flags = 0; /* neither complete, nor being deleted */
 186                 goto success;
 187         }
 188         if (!strcmp(dash + 1, "incomplete.being_deleted")) {
 189                 s->completion_time = -1;
 190                 s->flags = SS_BEING_DELETED; /* mot cpmplete, being deleted */
 191                 goto success;
 192         }
 193         tmp = dash + 1;
 194         dot = strchr(tmp, '.');
 195         if (!dot || !dot[1] || dot == tmp)
 196                 return 0;
 197         for (i = 0; tmp[i] != '.'; i++)
 198                 if (!isdigit(tmp[i]))
 199                         return 0;
 200         tmp = dss_strdup(dash + 1);
 201         tmp[i] = '\0';
 202         ret = dss_atoi64(tmp, &num);
 203         free(tmp);
 204         if (ret < 0) {
 205                 free(dss_error_txt);
 206                 return 0;
 207         }
 208         if (num > now)
 209                 return 0;
 210         s->completion_time = num;
 211         s->flags = SS_COMPLETE;
 212         if (!strcmp(dot + 1, "being_deleted"))
 213                 s->flags |= SS_BEING_DELETED;
 214 success:
 215         s->name = dss_strdup(dirname);
 216         return 1;
 217 }
 218
 219 int64_t get_current_time(void)
 220 {
 221         time_t now;
 222         time(&now);
 223         DSS_DEBUG_LOG("now: %lli\n", (long long) now);
 224         return (int64_t)now;
 225 }
 226
 227 char *incomplete_name(int64_t start)
 228 {
 229         return make_message("%lli-incomplete", (long long)start);
 230 }
 231
 232 char *being_deleted_name(struct snapshot *s)
 233 {
 234         if (s->flags & SS_COMPLETE)
 235                 return make_message("%lli-%lli.being_deleted",
 236                         (long long)s->creation_time,
 237                         (long long)s->completion_time);
 238         return make_message("%lli-incomplete.being_deleted",
 239                 (long long)s->creation_time);
 240 }
 241
 242 int complete_name(int64_t start, int64_t end, char **result)
 243 {
 244         struct tm start_tm, end_tm;
 245         time_t *start_seconds = (time_t *) (uint64_t *)&start; /* STFU, gcc */
 246         time_t *end_seconds = (time_t *) (uint64_t *)&end; /* STFU, gcc */
 247         char start_str[200], end_str[200];
 248
 249         if (!localtime_r(start_seconds, &start_tm)) {
 250                 make_err_msg("%lli", (long long)start);
 251                 return -E_LOCALTIME;
 252         }
 253         if (!localtime_r(end_seconds, &end_tm)) {
 254                 make_err_msg("%lli", (long long)end);
 255                 return -E_LOCALTIME;
 256         }
 257         if (!strftime(start_str, sizeof(start_str), "%a_%b_%d_%Y_%H_%M_%S", &start_tm)) {
 258                 make_err_msg("%lli", (long long)start);
 259                 return -E_STRFTIME;
 260         }
 261         if (!strftime(end_str, sizeof(end_str), "%a_%b_%d_%Y_%H_%M_%S", &end_tm)) {
 262                 make_err_msg("%lli", (long long)end);
 263                 return -E_STRFTIME;
 264         }
 265         *result = make_message("%lli-%lli.%s-%s", (long long) start, (long long) end,
 266                 start_str, end_str);
 267         return 1;
 268 }
 269
 270 struct snapshot_list {
 271         int64_t now;
 272         unsigned num_snapshots;
 273         unsigned array_size;
 274         struct snapshot **snapshots;
 275         /**
 276          * Array of size num_intervals + 1
 277          *
 278          * It contains the number of snapshots in each interval. interval_count[num_intervals]
 279          * is the number of snapshots which belong to any interval greater than num_intervals.
 280          */
 281         unsigned *interval_count;
 282 };
 283
 284 #define FOR_EACH_SNAPSHOT(s, i, sl) \
 285         for ((i) = 0; (i) < (sl)->num_snapshots && ((s) = (sl)->snapshots[(i)]); (i)++)
 286
 287
 288
 289 #define NUM_COMPARE(x, y) ((int)((x) < (y)) - (int)((x) > (y)))
 290
 291 static int compare_snapshots(const void *a, const void *b)
 292 {
 293         struct snapshot *s1 = *(struct snapshot **)a;
 294         struct snapshot *s2 = *(struct snapshot **)b;
 295         return NUM_COMPARE(s2->creation_time, s1->creation_time);
 296 }
 297
 298 /** Compute the minimum of \a a and \a b. */
 299 #define DSS_MIN(a,b) ((a) < (b) ? (a) : (b))
 300
 301 int add_snapshot(const char *dirname, void *private)
 302 {
 303         struct snapshot_list *sl = private;
 304         struct snapshot s;
 305         int ret = is_snapshot(dirname, sl->now, &s);
 306
 307         if (!ret)
 308                 return 1;
 309         if (sl->num_snapshots >= sl->array_size) {
 310                 sl->array_size = 2 * sl->array_size + 1;
 311                 sl->snapshots = dss_realloc(sl->snapshots,
 312                         sl->array_size * sizeof(struct snapshot *));
 313         }
 314         sl->snapshots[sl->num_snapshots] = dss_malloc(sizeof(struct snapshot));
 315         *(sl->snapshots[sl->num_snapshots]) = s;
 316         sl->interval_count[DSS_MIN(s.interval, conf.num_intervals_arg)]++;
 317         sl->num_snapshots++;
 318         return 1;
 319 }
 320
 321 void get_snapshot_list(struct snapshot_list *sl)
 322 {
 323         sl->now = get_current_time();
 324         sl->num_snapshots = 0;
 325         sl->array_size = 0;
 326         sl->snapshots = NULL;
 327         sl->interval_count = dss_calloc((conf.num_intervals_arg + 1) * sizeof(unsigned));
 328         for_each_subdir(add_snapshot, sl);
 329         qsort(sl->snapshots, sl->num_snapshots, sizeof(struct snapshot *),
 330                 compare_snapshots);
 331 }
 332
 333 void free_snapshot_list(struct snapshot_list *sl)
 334 {
 335         int i;
 336         struct snapshot *s;
 337
 338         FOR_EACH_SNAPSHOT(s, i, sl) {
 339                 free(s->name);
 340                 free(s);
 341         }
 342         free(sl->interval_count);
 343         free(sl->snapshots);
 344 }
 345
 346 void stop_rsync_process(void)
 347 {
 348         if (!rsync_pid || rsync_stopped)
 349                 return;
 350         kill(SIGSTOP, rsync_pid);
 351         rsync_stopped = 1;
 352 }
 353
 354 void restart_rsync_process(void)
 355 {
 356         if (!rsync_pid || !rsync_stopped)
 357                 return;
 358         kill (SIGCONT, rsync_pid);
 359         rsync_stopped = 0;
 360 }
 361
 362 /**
 363  * Print a log message about the exit status of a child.
 364  */
 365 void log_termination_msg(pid_t pid, int status)
 366 {
 367         if (WIFEXITED(status))
 368                 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
 369                         WEXITSTATUS(status));
 370         else if (WIFSIGNALED(status))
 371                 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
 372                         WTERMSIG(status));
 373         else
 374                 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
 375 }
 376
 377 int wait_for_process(pid_t pid, int *status)
 378 {
 379         int ret;
 380
 381         DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
 382         for (;;) {
 383                 pause();
 384                 ret = next_signal();
 385                 if (ret < 0)
 386                         break;
 387                 if (!ret)
 388                         continue;
 389                 if (ret == SIGCHLD) {
 390                         ret = waitpid(pid, status, 0);
 391                         if (ret >= 0)
 392                                 break;
 393                         if (errno != EINTR) { /* error */
 394                                 ret = -ERRNO_TO_DSS_ERROR(errno);
 395                                 break;
 396                         }
 397                 }
 398                 /* SIGINT or SIGTERM */
 399                 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
 400                 kill(pid, SIGTERM);
 401         }
 402         if (ret < 0)
 403                 make_err_msg("failed to wait for process %d", (int)pid);
 404         else
 405                 log_termination_msg(pid, *status);
 406         return ret;
 407 }
 408
 409 int remove_snapshot(struct snapshot *s)
 410 {
 411         int fds[3] = {0, 0, 0};
 412         assert(!rm_pid);
 413         char *new_name = being_deleted_name(s);
 414         int ret = dss_rename(s->name, new_name);
 415         char *argv[] = {"rm", "-rf", new_name, NULL};
 416
 417         if (ret < 0)
 418                 goto out;
 419         DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
 420         stop_rsync_process();
 421         ret = dss_exec(&rm_pid, argv[0], argv, fds);
 422 out:
 423         free(new_name);
 424         return ret;
 425 }
 426
 427 /*
 428  * return: 0: no redundant snapshots, 1: rm process started, negative: error
 429  */
 430 int remove_redundant_snapshot(struct snapshot_list *sl)
 431 {
 432         int ret, i, interval;
 433         struct snapshot *s;
 434         unsigned missing = 0;
 435
 436         DSS_INFO_LOG("looking for intervals containing too many snapshots\n");
 437         for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
 438                 unsigned keep = num_snapshots(interval);
 439                 unsigned num = sl->interval_count[interval];
 440                 struct snapshot *victim = NULL, *prev = NULL;
 441                 int64_t score = LONG_MAX;
 442
 443                 if (keep >= num)
 444                         missing += keep - num;
 445                 DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
 446                         interval, keep, num, missing);
 447                 if (keep + missing >= num)
 448                         continue;
 449                 /* redundant snapshot in this interval, pick snapshot with lowest score */
 450                 FOR_EACH_SNAPSHOT(s, i, sl) {
 451                         int64_t this_score;
 452
 453                         //DSS_DEBUG_LOG("checking %s\n", s->name);
 454                         if (s->interval > interval) {
 455                                 prev = s;
 456                                 continue;
 457                         }
 458                         if (s->interval < interval)
 459                                 break;
 460                         if (!victim) {
 461                                 victim = s;
 462                                 prev = s;
 463                                 continue;
 464                         }
 465                         assert(prev);
 466                         /* check if s is a better victim */
 467                         this_score = s->creation_time - prev->creation_time;
 468                         assert(this_score >= 0);
 469                         //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
 470                         if (this_score < score) {
 471                                 score = this_score;
 472                                 victim = s;
 473                         }
 474                         prev = s;
 475                 }
 476                 assert(victim);
 477                 if (conf.dry_run_given) {
 478                         dss_msg("%s would be removed (interval = %i)\n",
 479                                 victim->name, victim->interval);
 480                         continue;
 481                 }
 482                 ret = remove_snapshot(victim);
 483                 return ret < 0? ret : 1;
 484         }
 485         return 0;
 486 }
 487
 488 int remove_outdated_snapshot(struct snapshot_list *sl)
 489 {
 490         int i, ret;
 491         struct snapshot *s;
 492
 493         DSS_INFO_LOG("looking for snapshots belonging to intervals greater than %d\n",
 494                 conf.num_intervals_arg);
 495         FOR_EACH_SNAPSHOT(s, i, sl) {
 496                 if (s->interval <= conf.num_intervals_arg)
 497                         continue;
 498                 if (conf.dry_run_given) {
 499                         dss_msg("%s would be removed (interval = %i)\n",
 500                                 s->name, s->interval);
 501                         continue;
 502                 }
 503                 ret = remove_snapshot(s);
 504                 if (ret < 0)
 505                         return ret;
 506                 return 1;
 507         }
 508         return 0;
 509 }
 510
 511 int handle_rm_exit(int status)
 512 {
 513         int es, ret;
 514
 515         if (!WIFEXITED(status)) {
 516                 make_err_msg("rm process %d died involuntary", (int)rm_pid);
 517                 ret = -E_INVOLUNTARY_EXIT;
 518                 goto out;
 519         }
 520         es = WEXITSTATUS(status);
 521         if (es) {
 522                 make_err_msg("rm process %d returned %d", (int)rm_pid, es);
 523                 ret = -E_BAD_EXIT_CODE;
 524                 goto out;
 525         }
 526         ret = 1;
 527         rm_pid = 0;
 528 out:
 529         return ret;
 530 }
 531
 532 int wait_for_rm_process(void)
 533 {
 534         int status, ret = wait_for_process(rm_pid, &status);
 535
 536         if (ret < 0)
 537                 return ret;
 538         return handle_rm_exit(status);
 539 }
 540
 541 void kill_process(pid_t pid)
 542 {
 543         if (!pid)
 544                 return;
 545         DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
 546         kill(pid, SIGTERM);
 547 }
 548
 549 void handle_sighup()
 550 {
 551         DSS_INFO_LOG("FIXME: no sighup handling yet\n");
 552 }
 553
 554 int rename_incomplete_snapshot(int64_t start)
 555 {
 556         char *old_name, *new_name;
 557         int ret;
 558
 559         ret = complete_name(start, get_current_time(), &new_name);
 560         if (ret < 0)
 561                 return ret;
 562         old_name = incomplete_name(start);
 563         ret = dss_rename(old_name, new_name);
 564         if (ret >= 0)
 565                 DSS_NOTICE_LOG("%s -> %s\n", old_name, new_name);
 566         free(old_name);
 567         free(new_name);
 568         return ret;
 569 }
 570
 571 int handle_rsync_exit(int status)
 572 {
 573         int es, ret;
 574
 575         if (!WIFEXITED(status)) {
 576                 make_err_msg("rsync process %d died involuntary", (int)rsync_pid);
 577                 ret = -E_INVOLUNTARY_EXIT;
 578                 goto out;
 579         }
 580         es = WEXITSTATUS(status);
 581         if (es != 0 && es != 23 && es != 24) {
 582                 make_err_msg("rsync process %d returned %d", (int)rsync_pid, es);
 583                 ret = -E_BAD_EXIT_CODE;
 584                 goto out;
 585         }
 586         ret = rename_incomplete_snapshot(current_snapshot_creation_time);
 587 out:
 588         rsync_pid = 0;
 589         current_snapshot_creation_time = 0;
 590         rsync_stopped = 0;
 591         return ret;
 592 }
 593
 594 int get_newest_complete(const char *dirname, void *private)
 595 {
 596         struct edge_snapshot_data *esd = private;
 597         struct snapshot s;
 598         int ret = is_snapshot(dirname, esd->now, &s);
 599
 600         if (ret <= 0)
 601                 return 1;
 602         if (s.flags != SS_COMPLETE) /* incomplete or being deleted */
 603                 return 1;
 604         if (s.creation_time < esd->snap.creation_time)
 605                 return 1;
 606         free(esd->snap.name);
 607         esd->snap = s;
 608         return 1;
 609 }
 610
 611 __malloc char *name_of_newest_complete_snapshot(void)
 612 {
 613         struct edge_snapshot_data esd = {
 614                 .now = get_current_time(),
 615                 .snap = {.creation_time = -1}
 616         };
 617         for_each_subdir(get_newest_complete, &esd);
 618         return esd.snap.name;
 619 }
 620
 621 void create_rsync_argv(char ***argv, int64_t *num)
 622 {
 623         char *logname, *newest = name_of_newest_complete_snapshot();
 624         int i = 0, j;
 625
 626         *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
 627         (*argv)[i++] = dss_strdup("rsync");
 628         (*argv)[i++] = dss_strdup("-aq");
 629         (*argv)[i++] = dss_strdup("--delete");
 630         for (j = 0; j < conf.rsync_option_given; j++)
 631                 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
 632         if (newest) {
 633                 DSS_INFO_LOG("using %s as reference snapshot\n", newest);
 634                 (*argv)[i++] = make_message("--link-dest=../%s", newest);
 635                 free(newest);
 636         } else
 637                 DSS_INFO_LOG("no previous snapshot found\n");
 638         if (conf.exclude_patterns_given) {
 639                 (*argv)[i++] = dss_strdup("--exclude-from");
 640                 (*argv)[i++] = dss_strdup(conf.exclude_patterns_arg);
 641
 642         }
 643         logname = dss_logname();
 644         if (conf.remote_user_given && !strcmp(conf.remote_user_arg, logname))
 645                 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
 646         else
 647                 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
 648                         conf.remote_user_arg : logname,
 649                         conf.remote_host_arg, conf.source_dir_arg);
 650         free(logname);
 651         *num = get_current_time();
 652         (*argv)[i++] = incomplete_name(*num);
 653         (*argv)[i++] = NULL;
 654         for (j = 0; j < i; j++)
 655                 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
 656 }
 657
 658 void free_rsync_argv(char **argv)
 659 {
 660         int i;
 661         for (i = 0; argv[i]; i++)
 662                 free(argv[i]);
 663         free(argv);
 664 }
 665
 666 int create_snapshot(char **argv)
 667 {
 668         int fds[3] = {0, 0, 0};
 669         char *name = incomplete_name(current_snapshot_creation_time);
 670
 671         DSS_NOTICE_LOG("creating new snapshot %s\n", name);
 672         free(name);
 673         return dss_exec(&rsync_pid, argv[0], argv, fds);
 674 }
 675
 676 void compute_next_snapshot_time(struct snapshot_list *sl)
 677 {
 678         struct timeval now, unit_interval = {.tv_sec = 24 * 3600 * conf.unit_interval_arg},
 679                 tmp, diff;
 680         int64_t x = 0;
 681         unsigned wanted = num_snapshots(0), num_complete_snapshots = 0;
 682         int i, ret;
 683         struct snapshot *s;
 684
 685         gettimeofday(&now, NULL);
 686         FOR_EACH_SNAPSHOT(s, i, sl) {
 687                 if (!(s->flags & SS_COMPLETE))
 688                         continue;
 689                 num_complete_snapshots++;
 690                 x += s->completion_time - s->creation_time;
 691         }
 692         assert(x >= 0);
 693         if (num_complete_snapshots)
 694                 x /= num_complete_snapshots; /* avg time to create one snapshot */
 695         x *= wanted; /* time to create all snapshots in interval 0 */
 696         tmp.tv_sec = x;
 697         tmp.tv_usec = 0;
 698         ret = tv_diff(&unit_interval, &tmp, &diff); /* time between creation */
 699         if (ret < 0) {
 700                 next_snapshot_time = now;
 701                 return;
 702         }
 703         tv_divide(wanted, &diff, &tmp);
 704         tv_add(&now, &tmp, &next_snapshot_time);
 705 }
 706
 707 void handle_signal(struct snapshot_list *sl)
 708 {
 709         int sig, ret = next_signal();
 710
 711         if (ret <= 0)
 712                 goto out;
 713         sig = ret;
 714         switch (sig) {
 715                 int status;
 716                 pid_t pid;
 717         case SIGINT:
 718         case SIGTERM:
 719                 restart_rsync_process();
 720                 kill_process(rsync_pid);
 721                 kill_process(rm_pid);
 722                 exit(EXIT_FAILURE);
 723         case SIGHUP:
 724                 handle_sighup();
 725                 break;
 726         case SIGCHLD:
 727                 ret = reap_child(&pid, &status);
 728                 if (ret <= 0)
 729                         break;
 730                 assert(pid == rsync_pid || pid == rm_pid);
 731                 if (pid == rsync_pid)
 732                         ret = handle_rsync_exit(status);
 733                 else
 734                         ret = handle_rm_exit(status);
 735                 free_snapshot_list(sl);
 736                 get_snapshot_list(sl);
 737                 compute_next_snapshot_time(sl);
 738         }
 739 out:
 740         if (ret < 0)
 741                 log_err_msg(ERROR, -ret);
 742 }
 743
 744 int get_oldest(const char *dirname, void *private)
 745 {
 746         struct edge_snapshot_data *esd = private;
 747         struct snapshot s;
 748         int ret = is_snapshot(dirname, esd->now, &s);
 749
 750         if (ret <= 0)
 751                 return 1;
 752         if (s.creation_time > esd->snap.creation_time)
 753                 return 1;
 754         free(esd->snap.name);
 755         esd->snap = s;
 756         return 1;
 757 }
 758
 759 int remove_oldest_snapshot()
 760 {
 761         int ret;
 762         struct edge_snapshot_data esd = {
 763                 .now = get_current_time(),
 764                 .snap = {.creation_time = LLONG_MAX}
 765         };
 766         for_each_subdir(get_oldest, &esd);
 767         if (!esd.snap.name) /* no snapshot found */
 768                 return 0;
 769         DSS_INFO_LOG("oldest snapshot: %s\n", esd.snap.name);
 770         ret = 0;
 771         if (esd.snap.creation_time == current_snapshot_creation_time)
 772                 goto out; /* do not remove the snapshot currently being created */
 773         ret = remove_snapshot(&esd.snap);
 774 out:
 775         free(esd.snap.name);
 776         return ret;
 777 }
 778
 779 /* TODO: Also consider number of inodes. */
 780 int disk_space_low(void)
 781 {
 782         struct disk_space ds;
 783         int ret = get_disk_space(".", &ds);
 784
 785         if (ret < 0)
 786                 return ret;
 787         if (conf.min_free_mb_arg)
 788                 if (ds.free_mb < conf.min_free_mb_arg)
 789                         return 1;
 790         if (conf.min_free_percent_arg)
 791                 if (ds.percent_free < conf.min_free_percent_arg)
 792                         return 1;
 793         return 0;
 794 }
 795
 796 int try_to_free_disk_space(int low_disk_space, struct snapshot_list *sl)
 797 {
 798         int ret;
 799
 800         ret = remove_outdated_snapshot(sl);
 801         if (ret) /* error, or we are removing something */
 802                 return ret;
 803         /* no outdated snapshot */
 804         ret = remove_redundant_snapshot(sl);
 805         if (ret)
 806                 return ret;
 807         if (!low_disk_space)
 808                 return 0;
 809         DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
 810         ret = remove_oldest_snapshot();
 811         if (ret)
 812                 return ret;
 813         make_err_msg("uhuhu: not enough disk space for a single snapshot");
 814         return  -ENOSPC;
 815 }
 816
 817 int select_loop(void)
 818 {
 819         int ret;
 820         struct timeval tv = {.tv_sec = 0, .tv_usec = 0};
 821         struct snapshot_list sl = {.num_snapshots = 0};
 822
 823         get_snapshot_list(&sl);
 824         compute_next_snapshot_time(&sl);
 825         for (;;) {
 826                 struct timeval now, *tvp = &tv;
 827                 fd_set rfds;
 828                 int low_disk_space;
 829                 char **rsync_argv;
 830
 831                 FD_ZERO(&rfds);
 832                 FD_SET(signal_pipe, &rfds);
 833                 if (rsync_pid)
 834                         tv.tv_sec = 60;
 835                 else if (rm_pid)
 836                         tvp = NULL;
 837                 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
 838                 if (ret < 0)
 839                         return ret;
 840                 if (FD_ISSET(signal_pipe, &rfds))
 841                         handle_signal(&sl);
 842                 if (rm_pid)
 843                         continue;
 844                 ret = disk_space_low();
 845                 if (ret < 0)
 846                         break;
 847                 low_disk_space = ret;
 848                 if (low_disk_space)
 849                         stop_rsync_process();
 850                 ret = try_to_free_disk_space(low_disk_space, &sl);
 851                 if (ret < 0)
 852                         break;
 853                 if (rm_pid)
 854                         continue;
 855                 if (rsync_pid) {
 856                         restart_rsync_process();
 857                         continue;
 858                 }
 859                 /* neither rsync nor rm are running. Start rsync? */
 860                 gettimeofday(&now, NULL);
 861                 if (tv_diff(&next_snapshot_time, &now, &tv) > 0)
 862                         continue;
 863                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
 864                 ret = create_snapshot(rsync_argv);
 865                 free_rsync_argv(rsync_argv);
 866                 if (ret < 0)
 867                         break;
 868         }
 869         free_snapshot_list(&sl);
 870         return ret;
 871 }
 872
 873 int com_run(void)
 874 {
 875         int ret;
 876
 877         if (conf.dry_run_given) {
 878                 make_err_msg("dry_run not supported by this command");
 879                 return -E_SYNTAX;
 880         }
 881         ret = install_sighandler(SIGHUP);
 882         if (ret < 0)
 883                 return ret;
 884         return select_loop();
 885 }
 886
 887 void log_disk_space(struct disk_space *ds)
 888 {
 889         DSS_INFO_LOG("free: %uM/%uM (%u%%), %u%% inodes unused\n",
 890                 ds->free_mb, ds->total_mb, ds->percent_free,
 891                 ds->percent_free_inodes);
 892 }
 893
 894 int com_prune(void)
 895 {
 896         int ret;
 897         struct snapshot_list sl;
 898         struct disk_space ds;
 899
 900         ret = get_disk_space(".", &ds);
 901         if (ret < 0)
 902                 return ret;
 903         log_disk_space(&ds);
 904         for (;;) {
 905                 get_snapshot_list(&sl);
 906                 ret = remove_outdated_snapshot(&sl);
 907                 free_snapshot_list(&sl);
 908                 if (ret < 0)
 909                         return ret;
 910                 if (!ret)
 911                         break;
 912                 ret = wait_for_rm_process();
 913                 if (ret < 0)
 914                         goto out;
 915         }
 916         for (;;) {
 917                 get_snapshot_list(&sl);
 918                 ret = remove_redundant_snapshot(&sl);
 919                 free_snapshot_list(&sl);
 920                 if (ret < 0)
 921                         return ret;
 922                 if (!ret)
 923                         break;
 924                 ret = wait_for_rm_process();
 925                 if (ret < 0)
 926                         goto out;
 927         }
 928         return 1;
 929 out:
 930         return ret;
 931 }
 932
 933 int com_create(void)
 934 {
 935         int ret, status;
 936         char **rsync_argv;
 937
 938         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
 939         if (conf.dry_run_given) {
 940                 int i;
 941                 char *msg = NULL;
 942                 for (i = 0; rsync_argv[i]; i++) {
 943                         char *tmp = msg;
 944                         msg = make_message("%s%s%s", tmp? tmp : "",
 945                                 tmp? " " : "", rsync_argv[i]);
 946                         free(tmp);
 947                 }
 948                 dss_msg("%s\n", msg);
 949                 free(msg);
 950                 return 1;
 951         }
 952         ret = create_snapshot(rsync_argv);
 953         if (ret < 0)
 954                 goto out;
 955         ret = wait_for_process(rsync_pid, &status);
 956         if (ret < 0)
 957                 goto out;
 958         ret = handle_rsync_exit(status);
 959 out:
 960         free_rsync_argv(rsync_argv);
 961         return ret;
 962 }
 963
 964 int com_ls(void)
 965 {
 966         int i;
 967         struct snapshot_list sl;
 968         struct snapshot *s;
 969         get_snapshot_list(&sl);
 970         FOR_EACH_SNAPSHOT(s, i, &sl)
 971                 dss_msg("%u\t%s\n", s->interval, s->name);
 972         free_snapshot_list(&sl);
 973         return 1;
 974 }
 975
 976 __noreturn void clean_exit(int status)
 977 {
 978         free(dss_error_txt);
 979         exit(status);
 980 }
 981
 982 int read_config_file(void)
 983 {
 984         int ret;
 985         char *config_file;
 986         struct stat statbuf;
 987
 988         if (conf.config_file_given)
 989                 config_file = dss_strdup(conf.config_file_arg);
 990         else {
 991                 char *home = get_homedir();
 992                 config_file = make_message("%s/.dssrc", home);
 993                 free(home);
 994         }
 995         ret = stat(config_file, &statbuf);
 996         if (ret && conf.config_file_given) {
 997                 ret = -ERRNO_TO_DSS_ERROR(errno);
 998                 make_err_msg("failed to stat config file %s", config_file);
 999                 goto out;
1000         }
1001         if (!ret) {
1002                 struct cmdline_parser_params params = {
1003                         .override = 0,
1004                         .initialize = 0,
1005                         .check_required = 0,
1006                         .check_ambiguity = 0
1007                 };
1008                 cmdline_parser_config_file(config_file, &conf, &params);
1009         }
1010         if (!conf.source_dir_given || !conf.dest_dir_given) {
1011                 ret = -E_SYNTAX;
1012                 make_err_msg("you need to specify both source_dir and dest_dir");
1013                 goto out;
1014         }
1015         ret = 1;
1016 out:
1017         free(config_file);
1018         return ret;
1019 }
1020
1021 int check_config(void)
1022 {
1023         if (conf.unit_interval_arg <= 0) {
1024                 make_err_msg("bad unit interval: %i", conf.unit_interval_arg);
1025                 return -E_INVALID_NUMBER;
1026         }
1027         DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
1028         if (conf.num_intervals_arg <= 0) {
1029                 make_err_msg("bad number of intervals  %i", conf.num_intervals_arg);
1030                 return -E_INVALID_NUMBER;
1031         }
1032         DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
1033         return 1;
1034 }
1035
1036 static void setup_signal_handling(void)
1037 {
1038         int ret;
1039
1040         DSS_INFO_LOG("setting up signal handlers\n");
1041         signal_pipe = signal_init(); /* always successful */
1042         ret = install_sighandler(SIGINT);
1043         if (ret < 0)
1044                 goto err;
1045         ret = install_sighandler(SIGTERM);
1046         if (ret < 0)
1047                 goto err;
1048         ret = install_sighandler(SIGCHLD);
1049         if (ret < 0)
1050                 goto err;
1051         return;
1052 err:
1053         DSS_EMERG_LOG("could not install signal handlers\n");
1054         exit(EXIT_FAILURE);
1055 }
1056
1057 int main(int argc, char **argv)
1058 {
1059         int ret;
1060
1061         cmdline_parser(argc, argv, &conf); /* aborts on errors */
1062         ret = read_config_file();
1063         if (ret < 0)
1064                 goto out;
1065         ret = check_config();
1066         if (ret < 0)
1067                 goto out;
1068         if (conf.logfile_given) {
1069                 logfile = open_log(conf.logfile_arg);
1070                 log_welcome(conf.loglevel_arg);
1071         }
1072         ret = dss_chdir(conf.dest_dir_arg);
1073         if (ret < 0)
1074                 goto out;
1075         if (conf.daemon_given)
1076                 daemon_init();
1077         setup_signal_handling();
1078         ret = call_command_handler();
1079 out:
1080         if (ret < 0)
1081                 log_err_msg(EMERG, -ret);
1082         clean_exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1083 }