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
  46 pid_t pre_create_hook_pid;
  47 pid_t post_create_hook_pid;
  48
  49 /* Creation time of the snapshot currently being created. */
  50 int64_t current_snapshot_creation_time;
  51
  52 static char *path_to_last_complete_snapshot;
  53
  54 enum {
  55         SCS_READY,
  56         SCS_PRE_HOOK_RUNNING,
  57         SCS_PRE_HOOK_SUCCESS,
  58         SCS_RSYNC_RUNNING,
  59         SCS_RSYNC_SUCCESS,
  60         SCS_POST_HOOK_RUNNING,
  61 };
  62
  63 static unsigned snapshot_creation_status;
  64
  65
  66 DEFINE_DSS_ERRLIST;
  67
  68
  69 /* a litte cpp magic helps to DRY */
  70 #define COMMANDS \
  71         COMMAND(ls) \
  72         COMMAND(create) \
  73         COMMAND(prune) \
  74         COMMAND(run)
  75 #define COMMAND(x) int com_ ##x(void);
  76 COMMANDS
  77 #undef COMMAND
  78 #define COMMAND(x) if (conf.x ##_given) return com_ ##x();
  79 int call_command_handler(void)
  80 {
  81         COMMANDS
  82         DSS_EMERG_LOG("BUG: did not find command handler\n");
  83         exit(EXIT_FAILURE);
  84 }
  85 #undef COMMAND
  86 #undef COMMANDS
  87
  88 /*
  89  * complete, not being deleted: 1204565370-1204565371.Sun_Mar_02_2008_14_33-Sun_Mar_02_2008_14_43
  90  * complete, being deleted: 1204565370-1204565371.being_deleted
  91  * incomplete, not being deleted: 1204565370-incomplete
  92  * incomplete, being deleted: 1204565370-incomplete.being_deleted
  93  */
  94 enum snapshot_status_flags {
  95         /** The rsync process terminated successfully. */
  96         SS_COMPLETE = 1,
  97         /** The rm process is running to remove this snapshot. */
  98         SS_BEING_DELETED = 2,
  99 };
 100
 101 struct snapshot {
 102         char *name;
 103         int64_t creation_time;
 104         int64_t completion_time;
 105         enum snapshot_status_flags flags;
 106         unsigned interval;
 107 };
 108
 109 /*
 110  * An edge snapshot is either the oldest one or the newest one.
 111  *
 112  * We need to find either of them occasionally: The create code
 113  * needs to know the newest snapshot because that is the one
 114  * used as the link destination dir. The pruning code needs to
 115  * find the oldest one in case disk space becomes low.
 116  */
 117 struct edge_snapshot_data {
 118         int64_t now;
 119         struct snapshot snap;
 120 };
 121
 122 __printf_2_3 void dss_log(int ll, const char* fmt,...)
 123 {
 124         va_list argp;
 125         FILE *outfd;
 126         struct tm *tm;
 127         time_t t1;
 128         char str[255] = "";
 129
 130         if (ll < conf.loglevel_arg)
 131                 return;
 132         outfd = logfile? logfile : stderr;
 133         time(&t1);
 134         tm = localtime(&t1);
 135         strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
 136         fprintf(outfd, "%s ", str);
 137         if (conf.loglevel_arg <= INFO)
 138                 fprintf(outfd, "%i: ", ll);
 139         va_start(argp, fmt);
 140         vfprintf(outfd, fmt, argp);
 141         va_end(argp);
 142 }
 143
 144 /**
 145  * Print a message either to stdout or to the log file.
 146  */
 147 __printf_1_2 void dss_msg(const char* fmt,...)
 148 {
 149         FILE *outfd = conf.daemon_given? logfile : stdout;
 150         va_list argp;
 151         va_start(argp, fmt);
 152         vfprintf(outfd, fmt, argp);
 153         va_end(argp);
 154 }
 155
 156 /**
 157  * Return the desired number of snapshots of an interval.
 158  */
 159 unsigned num_snapshots(int interval)
 160 {
 161         unsigned n;
 162
 163         assert(interval >= 0);
 164
 165         if (interval >= conf.num_intervals_arg)
 166                 return 0;
 167         n = conf.num_intervals_arg - interval - 1;
 168         return 1 << n;
 169 }
 170
 171 /* return: Whether dirname is a snapshot directory (0: no, 1: yes) */
 172 int is_snapshot(const char *dirname, int64_t now, struct snapshot *s)
 173 {
 174         int i, ret;
 175         char *dash, *dot, *tmp;
 176         int64_t num;
 177
 178         assert(dirname);
 179         dash = strchr(dirname, '-');
 180         if (!dash || !dash[1] || dash == dirname)
 181                 return 0;
 182         for (i = 0; dirname[i] != '-'; i++)
 183                 if (!isdigit(dirname[i]))
 184                         return 0;
 185         tmp = dss_strdup(dirname);
 186         tmp[i] = '\0';
 187         ret = dss_atoi64(tmp, &num);
 188         free(tmp);
 189         if (ret < 0) {
 190                 free(dss_error_txt);
 191                 return 0;
 192         }
 193         assert(num >= 0);
 194         if (num > now)
 195                 return 0;
 196         s->creation_time = num;
 197         //DSS_DEBUG_LOG("%s start time: %lli\n", dirname, (long long)s->creation_time);
 198         s->interval = (long long) ((now - s->creation_time)
 199                 / conf.unit_interval_arg / 24 / 3600);
 200         if (!strcmp(dash + 1, "incomplete")) {
 201                 s->completion_time = -1;
 202                 s->flags = 0; /* neither complete, nor being deleted */
 203                 goto success;
 204         }
 205         if (!strcmp(dash + 1, "incomplete.being_deleted")) {
 206                 s->completion_time = -1;
 207                 s->flags = SS_BEING_DELETED; /* mot cpmplete, being deleted */
 208                 goto success;
 209         }
 210         tmp = dash + 1;
 211         dot = strchr(tmp, '.');
 212         if (!dot || !dot[1] || dot == tmp)
 213                 return 0;
 214         for (i = 0; tmp[i] != '.'; i++)
 215                 if (!isdigit(tmp[i]))
 216                         return 0;
 217         tmp = dss_strdup(dash + 1);
 218         tmp[i] = '\0';
 219         ret = dss_atoi64(tmp, &num);
 220         free(tmp);
 221         if (ret < 0) {
 222                 free(dss_error_txt);
 223                 return 0;
 224         }
 225         if (num > now)
 226                 return 0;
 227         s->completion_time = num;
 228         s->flags = SS_COMPLETE;
 229         if (!strcmp(dot + 1, "being_deleted"))
 230                 s->flags |= SS_BEING_DELETED;
 231 success:
 232         s->name = dss_strdup(dirname);
 233         return 1;
 234 }
 235
 236 int64_t get_current_time(void)
 237 {
 238         time_t now;
 239         time(&now);
 240         DSS_DEBUG_LOG("now: %lli\n", (long long) now);
 241         return (int64_t)now;
 242 }
 243
 244 char *incomplete_name(int64_t start)
 245 {
 246         return make_message("%lli-incomplete", (long long)start);
 247 }
 248
 249 char *being_deleted_name(struct snapshot *s)
 250 {
 251         if (s->flags & SS_COMPLETE)
 252                 return make_message("%lli-%lli.being_deleted",
 253                         (long long)s->creation_time,
 254                         (long long)s->completion_time);
 255         return make_message("%lli-incomplete.being_deleted",
 256                 (long long)s->creation_time);
 257 }
 258
 259 int complete_name(int64_t start, int64_t end, char **result)
 260 {
 261         struct tm start_tm, end_tm;
 262         time_t *start_seconds = (time_t *) (uint64_t *)&start; /* STFU, gcc */
 263         time_t *end_seconds = (time_t *) (uint64_t *)&end; /* STFU, gcc */
 264         char start_str[200], end_str[200];
 265
 266         if (!localtime_r(start_seconds, &start_tm)) {
 267                 make_err_msg("%lli", (long long)start);
 268                 return -E_LOCALTIME;
 269         }
 270         if (!localtime_r(end_seconds, &end_tm)) {
 271                 make_err_msg("%lli", (long long)end);
 272                 return -E_LOCALTIME;
 273         }
 274         if (!strftime(start_str, sizeof(start_str), "%a_%b_%d_%Y_%H_%M_%S", &start_tm)) {
 275                 make_err_msg("%lli", (long long)start);
 276                 return -E_STRFTIME;
 277         }
 278         if (!strftime(end_str, sizeof(end_str), "%a_%b_%d_%Y_%H_%M_%S", &end_tm)) {
 279                 make_err_msg("%lli", (long long)end);
 280                 return -E_STRFTIME;
 281         }
 282         *result = make_message("%lli-%lli.%s-%s", (long long) start, (long long) end,
 283                 start_str, end_str);
 284         return 1;
 285 }
 286
 287 struct snapshot_list {
 288         int64_t now;
 289         unsigned num_snapshots;
 290         unsigned array_size;
 291         struct snapshot **snapshots;
 292         /**
 293          * Array of size num_intervals + 1
 294          *
 295          * It contains the number of snapshots in each interval. interval_count[num_intervals]
 296          * is the number of snapshots which belong to any interval greater than num_intervals.
 297          */
 298         unsigned *interval_count;
 299 };
 300
 301 #define FOR_EACH_SNAPSHOT(s, i, sl) \
 302         for ((i) = 0; (i) < (sl)->num_snapshots && ((s) = (sl)->snapshots[(i)]); (i)++)
 303
 304
 305
 306 #define NUM_COMPARE(x, y) ((int)((x) < (y)) - (int)((x) > (y)))
 307
 308 static int compare_snapshots(const void *a, const void *b)
 309 {
 310         struct snapshot *s1 = *(struct snapshot **)a;
 311         struct snapshot *s2 = *(struct snapshot **)b;
 312         return NUM_COMPARE(s2->creation_time, s1->creation_time);
 313 }
 314
 315 /** Compute the minimum of \a a and \a b. */
 316 #define DSS_MIN(a,b) ((a) < (b) ? (a) : (b))
 317
 318 int add_snapshot(const char *dirname, void *private)
 319 {
 320         struct snapshot_list *sl = private;
 321         struct snapshot s;
 322         int ret = is_snapshot(dirname, sl->now, &s);
 323
 324         if (!ret)
 325                 return 1;
 326         if (sl->num_snapshots >= sl->array_size) {
 327                 sl->array_size = 2 * sl->array_size + 1;
 328                 sl->snapshots = dss_realloc(sl->snapshots,
 329                         sl->array_size * sizeof(struct snapshot *));
 330         }
 331         sl->snapshots[sl->num_snapshots] = dss_malloc(sizeof(struct snapshot));
 332         *(sl->snapshots[sl->num_snapshots]) = s;
 333         sl->interval_count[DSS_MIN(s.interval, conf.num_intervals_arg)]++;
 334         sl->num_snapshots++;
 335         return 1;
 336 }
 337
 338 void get_snapshot_list(struct snapshot_list *sl)
 339 {
 340         sl->now = get_current_time();
 341         sl->num_snapshots = 0;
 342         sl->array_size = 0;
 343         sl->snapshots = NULL;
 344         sl->interval_count = dss_calloc((conf.num_intervals_arg + 1) * sizeof(unsigned));
 345         for_each_subdir(add_snapshot, sl);
 346         qsort(sl->snapshots, sl->num_snapshots, sizeof(struct snapshot *),
 347                 compare_snapshots);
 348 }
 349
 350 void free_snapshot_list(struct snapshot_list *sl)
 351 {
 352         int i;
 353         struct snapshot *s;
 354
 355         FOR_EACH_SNAPSHOT(s, i, sl) {
 356                 free(s->name);
 357                 free(s);
 358         }
 359         free(sl->interval_count);
 360         sl->interval_count = NULL;
 361         free(sl->snapshots);
 362         sl->snapshots = NULL;
 363         sl->num_snapshots = 0;
 364 }
 365
 366 void stop_rsync_process(void)
 367 {
 368         if (!rsync_pid || rsync_stopped)
 369                 return;
 370         kill(SIGSTOP, rsync_pid);
 371         rsync_stopped = 1;
 372 }
 373
 374 void restart_rsync_process(void)
 375 {
 376         if (!rsync_pid || !rsync_stopped)
 377                 return;
 378         kill (SIGCONT, rsync_pid);
 379         rsync_stopped = 0;
 380 }
 381
 382 /**
 383  * Print a log message about the exit status of a child.
 384  */
 385 void log_termination_msg(pid_t pid, int status)
 386 {
 387         if (WIFEXITED(status))
 388                 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
 389                         WEXITSTATUS(status));
 390         else if (WIFSIGNALED(status))
 391                 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
 392                         WTERMSIG(status));
 393         else
 394                 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
 395 }
 396
 397 int wait_for_process(pid_t pid, int *status)
 398 {
 399         int ret;
 400
 401         DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
 402         for (;;) {
 403                 fd_set rfds;
 404
 405                 FD_ZERO(&rfds);
 406                 FD_SET(signal_pipe, &rfds);
 407                 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
 408                 if (ret < 0)
 409                         break;
 410                 ret = next_signal();
 411                 if (!ret)
 412                         continue;
 413                 if (ret == SIGCHLD) {
 414                         ret = waitpid(pid, status, 0);
 415                         if (ret >= 0)
 416                                 break;
 417                         if (errno != EINTR) { /* error */
 418                                 ret = -ERRNO_TO_DSS_ERROR(errno);
 419                                 break;
 420                         }
 421                 }
 422                 /* SIGINT or SIGTERM */
 423                 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
 424                 kill(pid, SIGTERM);
 425         }
 426         if (ret < 0)
 427                 make_err_msg("failed to wait for process %d", (int)pid);
 428         else
 429                 log_termination_msg(pid, *status);
 430         return ret;
 431 }
 432
 433 int remove_snapshot(struct snapshot *s)
 434 {
 435         int fds[3] = {0, 0, 0};
 436         assert(!rm_pid);
 437         char *new_name = being_deleted_name(s);
 438         int ret = dss_rename(s->name, new_name);
 439         char *argv[] = {"rm", "-rf", new_name, NULL};
 440
 441         if (ret < 0)
 442                 goto out;
 443         DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
 444         stop_rsync_process();
 445         ret = dss_exec(&rm_pid, argv[0], argv, fds);
 446 out:
 447         free(new_name);
 448         return ret;
 449 }
 450
 451 /*
 452  * return: 0: no redundant snapshots, 1: rm process started, negative: error
 453  */
 454 int remove_redundant_snapshot(struct snapshot_list *sl)
 455 {
 456         int ret, i, interval;
 457         struct snapshot *s;
 458         unsigned missing = 0;
 459
 460         DSS_INFO_LOG("looking for intervals containing too many snapshots\n");
 461         for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
 462                 unsigned keep = num_snapshots(interval);
 463                 unsigned num = sl->interval_count[interval];
 464                 struct snapshot *victim = NULL, *prev = NULL;
 465                 int64_t score = LONG_MAX;
 466
 467                 if (keep >= num)
 468                         missing += keep - num;
 469 //              DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
 470 //                      interval, keep, num, missing);
 471                 if (keep + missing >= num)
 472                         continue;
 473                 /* redundant snapshot in this interval, pick snapshot with lowest score */
 474                 FOR_EACH_SNAPSHOT(s, i, sl) {
 475                         int64_t this_score;
 476
 477                         //DSS_DEBUG_LOG("checking %s\n", s->name);
 478                         if (s->interval > interval) {
 479                                 prev = s;
 480                                 continue;
 481                         }
 482                         if (s->interval < interval)
 483                                 break;
 484                         if (!victim) {
 485                                 victim = s;
 486                                 prev = s;
 487                                 continue;
 488                         }
 489                         assert(prev);
 490                         /* check if s is a better victim */
 491                         this_score = s->creation_time - prev->creation_time;
 492                         assert(this_score >= 0);
 493                         //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
 494                         if (this_score < score) {
 495                                 score = this_score;
 496                                 victim = s;
 497                         }
 498                         prev = s;
 499                 }
 500                 assert(victim);
 501                 if (conf.dry_run_given) {
 502                         dss_msg("%s would be removed (interval = %i)\n",
 503                                 victim->name, victim->interval);
 504                         continue;
 505                 }
 506                 ret = remove_snapshot(victim);
 507                 return ret < 0? ret : 1;
 508         }
 509         return 0;
 510 }
 511
 512 int remove_outdated_snapshot(struct snapshot_list *sl)
 513 {
 514         int i, ret;
 515         struct snapshot *s;
 516
 517         DSS_INFO_LOG("looking for snapshots belonging to intervals greater than %d\n",
 518                 conf.num_intervals_arg);
 519         FOR_EACH_SNAPSHOT(s, i, sl) {
 520                 if (s->interval <= conf.num_intervals_arg)
 521                         continue;
 522                 if (conf.dry_run_given) {
 523                         dss_msg("%s would be removed (interval = %i)\n",
 524                                 s->name, s->interval);
 525                         continue;
 526                 }
 527                 ret = remove_snapshot(s);
 528                 if (ret < 0)
 529                         return ret;
 530                 return 1;
 531         }
 532         return 0;
 533 }
 534
 535 int handle_rm_exit(int status)
 536 {
 537         int es, ret;
 538
 539         if (!WIFEXITED(status)) {
 540                 make_err_msg("rm process %d died involuntary", (int)rm_pid);
 541                 ret = -E_INVOLUNTARY_EXIT;
 542                 goto out;
 543         }
 544         es = WEXITSTATUS(status);
 545         if (es) {
 546                 make_err_msg("rm process %d returned %d", (int)rm_pid, es);
 547                 ret = -E_BAD_EXIT_CODE;
 548                 goto out;
 549         }
 550         ret = 1;
 551         rm_pid = 0;
 552 out:
 553         return ret;
 554 }
 555
 556 int wait_for_rm_process(void)
 557 {
 558         int status, ret = wait_for_process(rm_pid, &status);
 559
 560         if (ret < 0)
 561                 return ret;
 562         return handle_rm_exit(status);
 563 }
 564
 565 void kill_process(pid_t pid)
 566 {
 567         if (!pid)
 568                 return;
 569         DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
 570         kill(pid, SIGTERM);
 571 }
 572
 573 int check_config(void)
 574 {
 575         if (conf.unit_interval_arg <= 0) {
 576                 make_err_msg("bad unit interval: %i", conf.unit_interval_arg);
 577                 return -E_INVALID_NUMBER;
 578         }
 579         DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
 580         if (conf.num_intervals_arg <= 0) {
 581                 make_err_msg("bad number of intervals  %i", conf.num_intervals_arg);
 582                 return -E_INVALID_NUMBER;
 583         }
 584         DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
 585         return 1;
 586 }
 587
 588 /* exits on errors */
 589 void parse_config_file(int override)
 590 {
 591         int ret;
 592         char *config_file;
 593         struct stat statbuf;
 594         char *old_logfile_arg = NULL;
 595         int old_daemon_given = 0;
 596
 597         if (conf.config_file_given)
 598                 config_file = dss_strdup(conf.config_file_arg);
 599         else {
 600                 char *home = get_homedir();
 601                 config_file = make_message("%s/.dssrc", home);
 602                 free(home);
 603         }
 604         if (override) { /* SIGHUP */
 605                 if (conf.logfile_given)
 606                         old_logfile_arg = dss_strdup(conf.logfile_arg);
 607                 old_daemon_given = conf.daemon_given;
 608         }
 609
 610         ret = stat(config_file, &statbuf);
 611         if (ret && conf.config_file_given) {
 612                 ret = -ERRNO_TO_DSS_ERROR(errno);
 613                 make_err_msg("failed to stat config file %s", config_file);
 614                 goto out;
 615         }
 616         if (!ret) {
 617                 struct cmdline_parser_params params = {
 618                         .override = override,
 619                         .initialize = 0,
 620                         .check_required = 1,
 621                         .check_ambiguity = 0
 622                 };
 623                 cmdline_parser_config_file(config_file, &conf, &params);
 624         }
 625         ret = check_config();
 626         if (ret < 0)
 627                 goto out;
 628         if (override) {
 629                 /* don't change daemon mode on SIGHUP */
 630                 conf.daemon_given = old_daemon_given;
 631                 close_log(logfile);
 632                 logfile = NULL;
 633                 if (conf.logfile_given)
 634                         free(old_logfile_arg);
 635                 else if (conf.daemon_given) { /* re-use old logfile */
 636                         conf.logfile_arg = old_logfile_arg;
 637                         conf.logfile_given = 1;
 638                 }
 639         }
 640         if (conf.logfile_given) {
 641                 logfile = open_log(conf.logfile_arg);
 642                 log_welcome(conf.loglevel_arg);
 643         }
 644         DSS_EMERG_LOG("loglevel: %d\n", conf.loglevel_arg);
 645 //      cmdline_parser_dump(logfile? logfile : stdout, &conf);
 646         ret = dss_chdir(conf.dest_dir_arg);
 647 out:
 648         free(config_file);
 649         if (ret >= 0)
 650                 return;
 651         log_err_msg(EMERG, -ret);
 652         exit(EXIT_FAILURE);
 653 }
 654
 655 void handle_sighup(void)
 656 {
 657         DSS_NOTICE_LOG("SIGHUP\n");
 658         parse_config_file(1);
 659 }
 660
 661 int rename_incomplete_snapshot(int64_t start)
 662 {
 663         char *old_name;
 664         int ret;
 665
 666         free(path_to_last_complete_snapshot);
 667         ret = complete_name(start, get_current_time(),
 668                 &path_to_last_complete_snapshot);
 669         if (ret < 0)
 670                 return ret;
 671         old_name = incomplete_name(start);
 672         ret = dss_rename(old_name, path_to_last_complete_snapshot);
 673         if (ret >= 0)
 674                 DSS_NOTICE_LOG("%s -> %s\n", old_name,
 675                         path_to_last_complete_snapshot);
 676         free(old_name);
 677         return ret;
 678 }
 679
 680 void compute_next_snapshot_time(void)
 681 {
 682         struct timeval now, unit_interval = {.tv_sec = 24 * 3600 * conf.unit_interval_arg},
 683                 tmp, diff;
 684         int64_t x = 0;
 685         unsigned wanted = num_snapshots(0), num_complete_snapshots = 0;
 686         int i, ret;
 687         struct snapshot *s = NULL;
 688         struct snapshot_list sl;
 689
 690         assert(snapshot_creation_status == SCS_READY);
 691         current_snapshot_creation_time = 0;
 692         get_snapshot_list(&sl);
 693         FOR_EACH_SNAPSHOT(s, i, &sl) {
 694                 if (!(s->flags & SS_COMPLETE))
 695                         continue;
 696                 num_complete_snapshots++;
 697                 x += s->completion_time - s->creation_time;
 698         }
 699         assert(x >= 0);
 700         if (num_complete_snapshots)
 701                 x /= num_complete_snapshots; /* avg time to create one snapshot */
 702         x *= wanted; /* time to create all snapshots in interval 0 */
 703         tmp.tv_sec = x;
 704         tmp.tv_usec = 0;
 705         ret = tv_diff(&unit_interval, &tmp, &diff); /* total sleep time per unit interval */
 706         gettimeofday(&now, NULL);
 707         if (ret < 0 || !s)
 708                 goto min_sleep;
 709         tv_divide(wanted, &diff, &tmp); /* sleep time betweeen two snapshots */
 710         diff.tv_sec = s->completion_time;
 711         diff.tv_usec = 0;
 712         tv_add(&diff, &tmp, &next_snapshot_time);
 713         if (tv_diff(&now, &next_snapshot_time, NULL) < 0)
 714                 goto out;
 715 min_sleep:
 716         next_snapshot_time = now;
 717         next_snapshot_time.tv_sec += 60;
 718 out:
 719         free_snapshot_list(&sl);
 720 }
 721
 722 int handle_rsync_exit(int status)
 723 {
 724         int es, ret;
 725
 726         if (!WIFEXITED(status)) {
 727                 make_err_msg("rsync process %d died involuntary", (int)rsync_pid);
 728                 ret = -E_INVOLUNTARY_EXIT;
 729                 snapshot_creation_status = SCS_READY;
 730                 compute_next_snapshot_time();
 731                 goto out;
 732         }
 733         es = WEXITSTATUS(status);
 734         if (es != 0 && es != 23 && es != 24) {
 735                 make_err_msg("rsync process %d returned %d", (int)rsync_pid, es);
 736                 ret = -E_BAD_EXIT_CODE;
 737                 snapshot_creation_status = SCS_READY;
 738                 compute_next_snapshot_time();
 739                 goto out;
 740         }
 741         ret = rename_incomplete_snapshot(current_snapshot_creation_time);
 742         if (ret < 0)
 743                 goto out;
 744         snapshot_creation_status = SCS_RSYNC_SUCCESS;
 745 out:
 746         rsync_pid = 0;
 747         rsync_stopped = 0;
 748         return ret;
 749 }
 750
 751 int get_newest_complete(const char *dirname, void *private)
 752 {
 753         struct edge_snapshot_data *esd = private;
 754         struct snapshot s;
 755         int ret = is_snapshot(dirname, esd->now, &s);
 756
 757         if (ret <= 0)
 758                 return 1;
 759         if (s.flags != SS_COMPLETE) /* incomplete or being deleted */
 760                 return 1;
 761         if (s.creation_time < esd->snap.creation_time)
 762                 return 1;
 763         free(esd->snap.name);
 764         esd->snap = s;
 765         return 1;
 766 }
 767
 768 __malloc char *name_of_newest_complete_snapshot(void)
 769 {
 770         struct edge_snapshot_data esd = {
 771                 .now = get_current_time(),
 772                 .snap = {.creation_time = -1}
 773         };
 774         for_each_subdir(get_newest_complete, &esd);
 775         return esd.snap.name;
 776 }
 777
 778 void create_rsync_argv(char ***argv, int64_t *num)
 779 {
 780         char *logname, *newest = name_of_newest_complete_snapshot();
 781         int i = 0, j;
 782
 783         *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
 784         (*argv)[i++] = dss_strdup("rsync");
 785         (*argv)[i++] = dss_strdup("-aq");
 786         (*argv)[i++] = dss_strdup("--delete");
 787         for (j = 0; j < conf.rsync_option_given; j++)
 788                 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
 789         if (newest) {
 790                 DSS_INFO_LOG("using %s as reference snapshot\n", newest);
 791                 (*argv)[i++] = make_message("--link-dest=../%s", newest);
 792                 free(newest);
 793         } else
 794                 DSS_INFO_LOG("no previous snapshot found\n");
 795         if (conf.exclude_patterns_given) {
 796                 (*argv)[i++] = dss_strdup("--exclude-from");
 797                 (*argv)[i++] = dss_strdup(conf.exclude_patterns_arg);
 798
 799         }
 800         logname = dss_logname();
 801         if (conf.remote_user_given && !strcmp(conf.remote_user_arg, logname))
 802                 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
 803         else
 804                 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
 805                         conf.remote_user_arg : logname,
 806                         conf.remote_host_arg, conf.source_dir_arg);
 807         free(logname);
 808         *num = get_current_time();
 809         (*argv)[i++] = incomplete_name(*num);
 810         (*argv)[i++] = NULL;
 811         for (j = 0; j < i; j++)
 812                 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
 813 }
 814
 815 void free_rsync_argv(char **argv)
 816 {
 817         int i;
 818         for (i = 0; argv[i]; i++)
 819                 free(argv[i]);
 820         free(argv);
 821 }
 822
 823 int pre_create_hook(void)
 824 {
 825         int ret, fds[3] = {0, 0, 0};
 826
 827         if (!conf.pre_create_hook_given) {
 828                 snapshot_creation_status = SCS_PRE_HOOK_SUCCESS;
 829                 return 0;
 830         }
 831         DSS_NOTICE_LOG("executing %s\n", conf.pre_create_hook_arg);
 832         ret = dss_exec_cmdline_pid(&pre_create_hook_pid,
 833                 conf.pre_create_hook_arg, fds);
 834         if (ret < 0)
 835                 return ret;
 836         snapshot_creation_status = SCS_PRE_HOOK_RUNNING;
 837         return ret;
 838 }
 839
 840 int post_create_hook(void)
 841 {
 842         int ret, fds[3] = {0, 0, 0};
 843         char *cmd;
 844
 845         if (!conf.post_create_hook_given) {
 846                 snapshot_creation_status = SCS_READY;
 847                 compute_next_snapshot_time();
 848                 return 0;
 849         }
 850         cmd = make_message("%s %s", conf.post_create_hook_arg,
 851                 path_to_last_complete_snapshot);
 852         DSS_NOTICE_LOG("executing %s\n", cmd);
 853         ret = dss_exec_cmdline_pid(&post_create_hook_pid, cmd, fds);
 854         free(cmd);
 855         if (ret < 0)
 856                 return ret;
 857         snapshot_creation_status = SCS_POST_HOOK_RUNNING;
 858         return ret;
 859 }
 860
 861 int create_snapshot(char **argv)
 862 {
 863         int ret, fds[3] = {0, 0, 0};
 864         char *name;
 865
 866         name = incomplete_name(current_snapshot_creation_time);
 867         DSS_NOTICE_LOG("creating new snapshot %s\n", name);
 868         free(name);
 869         ret = dss_exec(&rsync_pid, argv[0], argv, fds);
 870         if (ret < 0)
 871                 return ret;
 872         snapshot_creation_status = SCS_RSYNC_RUNNING;
 873         return ret;
 874 }
 875
 876 int handle_pre_create_hook_exit(int status)
 877 {
 878         int es, ret;
 879
 880         if (!WIFEXITED(status)) {
 881                 make_err_msg("pre-create-hook %d died involuntary",
 882                         (int)pre_create_hook_pid);
 883                 snapshot_creation_status = SCS_READY;
 884                 compute_next_snapshot_time();
 885                 ret = -E_INVOLUNTARY_EXIT;
 886                 goto out;
 887         }
 888         es = WEXITSTATUS(status);
 889         if (es) {
 890                 make_err_msg("pre-create-hook %d returned %d",
 891                         (int)pre_create_hook_pid, es);
 892                 snapshot_creation_status = SCS_READY;
 893                 compute_next_snapshot_time();
 894                 ret = -E_BAD_EXIT_CODE;
 895                 goto out;
 896         }
 897         snapshot_creation_status = SCS_PRE_HOOK_SUCCESS;
 898         ret = 1;
 899 out:
 900         pre_create_hook_pid = 0;
 901         return ret;
 902 }
 903
 904 int handle_sigchld()
 905 {
 906         pid_t pid;
 907         int status, ret = reap_child(&pid, &status);
 908
 909         if (ret <= 0)
 910                 return ret;
 911         if (pid == rsync_pid)
 912                 return handle_rsync_exit(status);
 913         if (pid == rm_pid)
 914                 return handle_rm_exit(status);
 915         if (pid == pre_create_hook_pid)
 916                 return handle_pre_create_hook_exit(status);
 917         if (pid == post_create_hook_pid) {
 918                 snapshot_creation_status = SCS_READY;
 919                 compute_next_snapshot_time();
 920                 return 1;
 921         }
 922         DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
 923         exit(EXIT_FAILURE);
 924 }
 925
 926 void handle_signal(void)
 927 {
 928         int sig, ret = next_signal();
 929
 930         if (ret <= 0)
 931                 goto out;
 932         sig = ret;
 933         switch (sig) {
 934         case SIGINT:
 935         case SIGTERM:
 936                 restart_rsync_process();
 937                 kill_process(rsync_pid);
 938                 kill_process(rm_pid);
 939                 exit(EXIT_FAILURE);
 940         case SIGHUP:
 941                 handle_sighup();
 942                 ret = 1;
 943                 break;
 944         case SIGCHLD:
 945                 ret = handle_sigchld();
 946                 break;
 947         }
 948 out:
 949         if (ret < 0)
 950                 log_err_msg(ERROR, -ret);
 951 }
 952
 953 int get_oldest(const char *dirname, void *private)
 954 {
 955         struct edge_snapshot_data *esd = private;
 956         struct snapshot s;
 957         int ret = is_snapshot(dirname, esd->now, &s);
 958
 959         if (ret <= 0)
 960                 return 1;
 961         if (s.creation_time > esd->snap.creation_time)
 962                 return 1;
 963         free(esd->snap.name);
 964         esd->snap = s;
 965         return 1;
 966 }
 967
 968 int remove_oldest_snapshot()
 969 {
 970         int ret;
 971         struct edge_snapshot_data esd = {
 972                 .now = get_current_time(),
 973                 .snap = {.creation_time = LLONG_MAX}
 974         };
 975         for_each_subdir(get_oldest, &esd);
 976         if (!esd.snap.name) /* no snapshot found */
 977                 return 0;
 978         DSS_INFO_LOG("oldest snapshot: %s\n", esd.snap.name);
 979         ret = 0;
 980         if (esd.snap.creation_time == current_snapshot_creation_time)
 981                 goto out; /* do not remove the snapshot currently being created */
 982         ret = remove_snapshot(&esd.snap);
 983 out:
 984         free(esd.snap.name);
 985         return ret;
 986 }
 987
 988 /* TODO: Also consider number of inodes. */
 989 int disk_space_low(void)
 990 {
 991         struct disk_space ds;
 992         int ret = get_disk_space(".", &ds);
 993
 994         if (ret < 0)
 995                 return ret;
 996         if (conf.min_free_mb_arg)
 997                 if (ds.free_mb < conf.min_free_mb_arg)
 998                         return 1;
 999         if (conf.min_free_percent_arg)
1000                 if (ds.percent_free < conf.min_free_percent_arg)
1001                         return 1;
1002         return 0;
1003 }
1004
1005 int try_to_free_disk_space(int low_disk_space)
1006 {
1007         int ret;
1008         struct snapshot_list sl;
1009
1010         get_snapshot_list(&sl);
1011         ret = remove_outdated_snapshot(&sl);
1012         if (ret) /* error, or we are removing something */
1013                 goto out;
1014         /* no outdated snapshot */
1015         ret = remove_redundant_snapshot(&sl);
1016         if (ret)
1017                 goto out;
1018         ret = 0;
1019         if (!low_disk_space)
1020                 goto out;
1021         DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
1022         ret = remove_oldest_snapshot();
1023         if (ret)
1024                 goto out;
1025         make_err_msg("uhuhu: not enough disk space for a single snapshot");
1026         ret= -ENOSPC;
1027 out:
1028         free_snapshot_list(&sl);
1029         return ret;
1030 }
1031
1032 int select_loop(void)
1033 {
1034         int ret;
1035         struct timeval tv = {.tv_sec = 0, .tv_usec = 0};
1036
1037         for (;;) {
1038                 fd_set rfds;
1039                 int low_disk_space;
1040                 char **rsync_argv;
1041                 struct timeval now, *tvp = &tv;
1042
1043                 if (rsync_pid)
1044                         tv.tv_sec = 60; /* check every 60 seconds for free disk space */
1045                 else if (rm_pid)
1046                         tvp = NULL; /* sleep until rm process dies */
1047                 FD_ZERO(&rfds);
1048                 FD_SET(signal_pipe, &rfds);
1049                 DSS_DEBUG_LOG("tvp: %p, tv_sec: %lu\n", tvp, (long unsigned) tv.tv_sec);
1050                 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
1051                 if (ret < 0)
1052                         return ret;
1053                 if (FD_ISSET(signal_pipe, &rfds))
1054                         handle_signal();
1055                 if (rm_pid)
1056                         continue;
1057                 ret = disk_space_low();
1058                 if (ret < 0)
1059                         break;
1060                 low_disk_space = ret;
1061                 if (low_disk_space)
1062                         stop_rsync_process();
1063                 ret = try_to_free_disk_space(low_disk_space);
1064                 if (ret < 0)
1065                         break;
1066                 if (rm_pid)
1067                         continue;
1068                 restart_rsync_process();
1069                 gettimeofday(&now, NULL);
1070                 if (tv_diff(&next_snapshot_time, &now, &tv) > 0)
1071                         continue;
1072                 switch (snapshot_creation_status) {
1073                 case SCS_READY:
1074                         ret = pre_create_hook();
1075                         if (ret < 0)
1076                                 goto out;
1077                         continue;
1078                 case SCS_PRE_HOOK_RUNNING:
1079                         continue;
1080                 case SCS_PRE_HOOK_SUCCESS:
1081                         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1082                         ret = create_snapshot(rsync_argv);
1083                         free_rsync_argv(rsync_argv);
1084                         if (ret < 0)
1085                                 goto out;
1086                         continue;
1087                 case SCS_RSYNC_RUNNING:
1088                         continue;
1089                 case SCS_RSYNC_SUCCESS:
1090                         ret = post_create_hook();
1091                         if (ret < 0)
1092                                 goto out;
1093                         continue;
1094                 case SCS_POST_HOOK_RUNNING:
1095                         continue;
1096                 }
1097         }
1098 out:
1099         return ret;
1100 }
1101
1102 int com_run(void)
1103 {
1104         int ret;
1105
1106         if (conf.dry_run_given) {
1107                 make_err_msg("dry_run not supported by this command");
1108                 return -E_SYNTAX;
1109         }
1110         ret = install_sighandler(SIGHUP);
1111         if (ret < 0)
1112                 return ret;
1113         compute_next_snapshot_time();
1114         return select_loop();
1115 }
1116
1117 void log_disk_space(struct disk_space *ds)
1118 {
1119         DSS_INFO_LOG("free: %uM/%uM (%u%%), %u%% inodes unused\n",
1120                 ds->free_mb, ds->total_mb, ds->percent_free,
1121                 ds->percent_free_inodes);
1122 }
1123
1124 int com_prune(void)
1125 {
1126         int ret;
1127         struct snapshot_list sl;
1128         struct disk_space ds;
1129
1130         ret = get_disk_space(".", &ds);
1131         if (ret < 0)
1132                 return ret;
1133         log_disk_space(&ds);
1134         for (;;) {
1135                 get_snapshot_list(&sl);
1136                 ret = remove_outdated_snapshot(&sl);
1137                 free_snapshot_list(&sl);
1138                 if (ret < 0)
1139                         return ret;
1140                 if (!ret)
1141                         break;
1142                 ret = wait_for_rm_process();
1143                 if (ret < 0)
1144                         goto out;
1145         }
1146         for (;;) {
1147                 get_snapshot_list(&sl);
1148                 ret = remove_redundant_snapshot(&sl);
1149                 free_snapshot_list(&sl);
1150                 if (ret < 0)
1151                         return ret;
1152                 if (!ret)
1153                         break;
1154                 ret = wait_for_rm_process();
1155                 if (ret < 0)
1156                         goto out;
1157         }
1158         return 1;
1159 out:
1160         return ret;
1161 }
1162
1163 int com_create(void)
1164 {
1165         int ret, status;
1166         char **rsync_argv;
1167
1168         if (conf.dry_run_given) {
1169                 int i;
1170                 char *msg = NULL;
1171                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1172                 for (i = 0; rsync_argv[i]; i++) {
1173                         char *tmp = msg;
1174                         msg = make_message("%s%s%s", tmp? tmp : "",
1175                                 tmp? " " : "", rsync_argv[i]);
1176                         free(tmp);
1177                 }
1178                 free_rsync_argv(rsync_argv);
1179                 dss_msg("%s\n", msg);
1180                 free(msg);
1181                 return 1;
1182         }
1183         ret = pre_create_hook();
1184         if (ret < 0)
1185                 return ret;
1186         if (pre_create_hook_pid) {
1187                 ret = wait_for_process(pre_create_hook_pid, &status);
1188                 if (ret < 0)
1189                         return ret;
1190                 ret = handle_pre_create_hook_exit(status);
1191                 if (ret < 0)
1192                         return ret;
1193         }
1194         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1195         ret = create_snapshot(rsync_argv);
1196         if (ret < 0)
1197                 goto out;
1198         ret = wait_for_process(rsync_pid, &status);
1199         if (ret < 0)
1200                 goto out;
1201         ret = handle_rsync_exit(status);
1202         if (ret < 0)
1203                 goto out;
1204         post_create_hook();
1205         if (post_create_hook_pid)
1206                 ret = wait_for_process(post_create_hook_pid, &status);
1207 out:
1208         free_rsync_argv(rsync_argv);
1209         return ret;
1210 }
1211
1212 int com_ls(void)
1213 {
1214         int i;
1215         struct snapshot_list sl;
1216         struct snapshot *s;
1217         get_snapshot_list(&sl);
1218         FOR_EACH_SNAPSHOT(s, i, &sl)
1219                 dss_msg("%u\t%s\n", s->interval, s->name);
1220         free_snapshot_list(&sl);
1221         return 1;
1222 }
1223
1224 __noreturn void clean_exit(int status)
1225 {
1226         free(dss_error_txt);
1227         exit(status);
1228 }
1229 static void setup_signal_handling(void)
1230 {
1231         int ret;
1232
1233         DSS_INFO_LOG("setting up signal handlers\n");
1234         signal_pipe = signal_init(); /* always successful */
1235         ret = install_sighandler(SIGINT);
1236         if (ret < 0)
1237                 goto err;
1238         ret = install_sighandler(SIGTERM);
1239         if (ret < 0)
1240                 goto err;
1241         ret = install_sighandler(SIGCHLD);
1242         if (ret < 0)
1243                 goto err;
1244         return;
1245 err:
1246         DSS_EMERG_LOG("could not install signal handlers\n");
1247         exit(EXIT_FAILURE);
1248 }
1249
1250 int main(int argc, char **argv)
1251 {
1252         int ret;
1253         struct cmdline_parser_params params = {
1254                 .override = 0,
1255                 .initialize = 1,
1256                 .check_required = 0,
1257                 .check_ambiguity = 0
1258         };
1259
1260         cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1261         parse_config_file(0);
1262
1263         if (conf.daemon_given)
1264                 daemon_init();
1265         setup_signal_handling();
1266         ret = call_command_handler();
1267         if (ret < 0)
1268                 log_err_msg(EMERG, -ret);
1269         clean_exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1270 }