dss.c

   1 /*
   2  * Copyright (C) 2008-2009 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 pre-create-hook/rsync/post-create-hook process. */
  44 static pid_t create_pid;
  45 /** Whether the pre-create-hook/rsync/post-create-hook is currently stopped. */
  46 static int create_process_stopped;
  47 /** Process id of current pre-remove/rm/post-remove process. */
  48 static pid_t remove_pid;
  49 /** When the next snapshot is due. */
  50 static int64_t next_snapshot_time;
  51 /** When to try to remove something. */
  52 static struct timeval next_removal_check;
  53 /** Creation time of the snapshot currently being created. */
  54 static int64_t current_snapshot_creation_time;
  55 /** The snapshot currently being removed. */
  56 struct snapshot *snapshot_currently_being_removed;
  57 /** Needed by the post-create hook. */
  58 static char *path_to_last_complete_snapshot;
  59 static char *name_of_reference_snapshot;
  60 /** \sa \ref snap.h for details. */
  61 enum hook_status snapshot_creation_status;
  62 /** \sa \ref snap.h for details. */
  63 enum hook_status snapshot_removal_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) static int com_ ##x(void);
  76 COMMANDS
  77 #undef COMMAND
  78 #define COMMAND(x) if (conf.x ##_given) return com_ ##x();
  79 static int call_command_handler(void)
  80 {
  81         COMMANDS
  82         DSS_EMERG_LOG("BUG: did not find command handler\n");
  83         return -E_BUG;
  84 }
  85 #undef COMMAND
  86 #undef COMMANDS
  87
  88 /**
  89  * The log function of dss.
  90  *
  91  * \param ll Loglevel.
  92  * \param fml Usual format string.
  93  *
  94  * All DSS_XXX_LOG() macros use this function.
  95  */
  96 __printf_2_3 void dss_log(int ll, const char* fmt,...)
  97 {
  98         va_list argp;
  99         FILE *outfd;
 100         struct tm *tm;
 101         time_t t1;
 102         char str[255] = "";
 103
 104         if (ll < conf.loglevel_arg)
 105                 return;
 106         outfd = logfile? logfile : stderr;
 107         time(&t1);
 108         tm = localtime(&t1);
 109         strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
 110         fprintf(outfd, "%s ", str);
 111         if (conf.loglevel_arg <= INFO)
 112                 fprintf(outfd, "%i: ", ll);
 113         va_start(argp, fmt);
 114         vfprintf(outfd, fmt, argp);
 115         va_end(argp);
 116 }
 117
 118 /**
 119  * Print a message either to stdout or to the log file.
 120  */
 121 static __printf_1_2 void dss_msg(const char* fmt,...)
 122 {
 123         FILE *outfd = conf.daemon_given? logfile : stdout;
 124         va_list argp;
 125         va_start(argp, fmt);
 126         vfprintf(outfd, fmt, argp);
 127         va_end(argp);
 128 }
 129
 130 static int disk_space_low(void)
 131 {
 132         struct disk_space ds;
 133         int ret = get_disk_space(".", &ds);
 134
 135         if (ret < 0)
 136                 return ret;
 137         if (conf.min_free_mb_arg)
 138                 if (ds.free_mb < conf.min_free_mb_arg)
 139                         return 1;
 140         if (conf.min_free_percent_arg)
 141                 if (ds.percent_free < conf.min_free_percent_arg)
 142                         return 1;
 143         if (conf.min_free_percent_inodes_arg)
 144                 if (ds.percent_free_inodes < conf.min_free_percent_inodes_arg)
 145                         return 1;
 146         return 0;
 147 }
 148
 149 static void dss_get_snapshot_list(struct snapshot_list *sl)
 150 {
 151         get_snapshot_list(sl, conf.unit_interval_arg, conf.num_intervals_arg);
 152 }
 153
 154 static int64_t compute_next_snapshot_time(void)
 155 {
 156         int64_t x = 0, now = get_current_time(), unit_interval
 157                 = 24 * 3600 * conf.unit_interval_arg, ret;
 158         unsigned wanted = desired_number_of_snapshots(0, conf.num_intervals_arg),
 159                 num_complete_snapshots = 0;
 160         int i;
 161         struct snapshot *s = NULL;
 162         struct snapshot_list sl;
 163
 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
 174         ret = now;
 175         if (num_complete_snapshots == 0)
 176                 goto out;
 177         x /= num_complete_snapshots; /* avg time to create one snapshot */
 178         if (unit_interval < x * wanted) /* oops, no sleep at all */
 179                 goto out;
 180         ret = s->completion_time + unit_interval / wanted - x;
 181 out:
 182         free_snapshot_list(&sl);
 183         return ret;
 184 }
 185
 186 static inline void invalidate_next_snapshot_time(void)
 187 {
 188         next_snapshot_time = 0;
 189 }
 190
 191 static inline int next_snapshot_time_is_valid(void)
 192 {
 193         return next_snapshot_time != 0;
 194 }
 195
 196 static int next_snapshot_is_due(void)
 197 {
 198         int64_t now = get_current_time();
 199
 200         assert(snapshot_creation_status == HS_READY);
 201         if (!next_snapshot_time_is_valid())
 202                 next_snapshot_time = compute_next_snapshot_time();
 203         if (next_snapshot_time <= now) {
 204                 DSS_DEBUG_LOG("next snapshot: now\n");
 205                 return 1;
 206         }
 207         DSS_DEBUG_LOG("next snapshot due in %" PRId64 " seconds\n",
 208                 next_snapshot_time - now);
 209         return 0;
 210 }
 211
 212 static int pre_create_hook(void)
 213 {
 214         int ret, fds[3] = {0, 0, 0};
 215
 216         assert(snapshot_creation_status == HS_READY);
 217         /* make sure that the next snapshot time will be recomputed */
 218         invalidate_next_snapshot_time();
 219         if (!conf.pre_create_hook_given) {
 220                 snapshot_creation_status = HS_PRE_SUCCESS;
 221                 return 0;
 222         }
 223         DSS_DEBUG_LOG("executing %s\n", conf.pre_create_hook_arg);
 224         ret = dss_exec_cmdline_pid(&create_pid,
 225                 conf.pre_create_hook_arg, fds);
 226         if (ret < 0)
 227                 return ret;
 228         snapshot_creation_status = HS_PRE_RUNNING;
 229         return ret;
 230 }
 231
 232 static int pre_remove_hook(struct snapshot *s, const char *why)
 233 {
 234         int ret, fds[3] = {0, 0, 0};
 235         char *cmd;
 236
 237         if (!s)
 238                 return 0;
 239         DSS_DEBUG_LOG("%s snapshot %s\n", why, s->name);
 240         assert(snapshot_removal_status == HS_READY);
 241         assert(remove_pid == 0);
 242         assert(!snapshot_currently_being_removed);
 243
 244         snapshot_currently_being_removed = dss_malloc(sizeof(struct snapshot));
 245         *snapshot_currently_being_removed = *s;
 246         snapshot_currently_being_removed->name = dss_strdup(s->name);
 247
 248         if (!conf.pre_remove_hook_given) {
 249                 snapshot_removal_status = HS_PRE_SUCCESS;
 250                 return 0;
 251         }
 252         cmd = make_message("%s %s/%s", conf.pre_remove_hook_arg,
 253                 conf.dest_dir_arg, s->name);
 254         DSS_DEBUG_LOG("executing %s\n", cmd);
 255         ret = dss_exec_cmdline_pid(&remove_pid,
 256                 conf.pre_remove_hook_arg, fds);
 257         free(cmd);
 258         if (ret < 0)
 259                 return ret;
 260         snapshot_removal_status = HS_PRE_RUNNING;
 261         return ret;
 262 }
 263
 264 static int exec_rm(void)
 265 {
 266         struct snapshot *s = snapshot_currently_being_removed;
 267         int fds[3] = {0, 0, 0};
 268         char *new_name = being_deleted_name(s);
 269         char *argv[] = {"rm", "-rf", new_name, NULL};
 270         int ret;
 271
 272         assert(snapshot_removal_status == HS_PRE_SUCCESS);
 273         assert(remove_pid == 0);
 274
 275         DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
 276         ret = dss_rename(s->name, new_name);
 277         if (ret < 0)
 278                 goto out;
 279         ret = dss_exec(&remove_pid, argv[0], argv, fds);
 280         if (ret < 0)
 281                 goto out;
 282         snapshot_removal_status = HS_RUNNING;
 283 out:
 284         free(new_name);
 285         return ret;
 286 }
 287
 288 static int snapshot_is_being_created(struct snapshot *s)
 289 {
 290         return s->creation_time == current_snapshot_creation_time;
 291 }
 292
 293 static struct snapshot *find_orphaned_snapshot(struct snapshot_list *sl)
 294 {
 295         struct snapshot *s;
 296         int i;
 297
 298         DSS_DEBUG_LOG("looking for orphaned snapshots\n");
 299         FOR_EACH_SNAPSHOT(s, i, sl) {
 300                 if (snapshot_is_being_created(s))
 301                         continue;
 302                 /*
 303                  * We know that no rm is currently running, so if s is marked
 304                  * as being deleted, a previously started rm must have failed.
 305                  */
 306                 if (s->flags & SS_BEING_DELETED)
 307                         return s;
 308
 309                 if (s->flags & SS_COMPLETE) /* good snapshot */
 310                         continue;
 311                 /*
 312                  * This snapshot is incomplete and it is not the snapshot
 313                  * currently being created. However, we must not remove it if
 314                  * rsync is about to be restarted. As only the newest snapshot
 315                  * can be restarted, this snapshot is orphaned if it is not the
 316                  * newest snapshot or if we are not about to restart rsync.
 317                  */
 318                 if (get_newest_snapshot(sl) != s)
 319                         return s;
 320                 if (snapshot_creation_status != HS_NEEDS_RESTART)
 321                         return s;
 322         }
 323         /* no orphaned snapshots */
 324         return NULL;
 325 }
 326
 327 static int is_reference_snapshot(struct snapshot *s)
 328 {
 329         if (!name_of_reference_snapshot)
 330                 return 0;
 331         return strcmp(s->name, name_of_reference_snapshot)? 0 : 1;
 332 }
 333
 334 /*
 335  * return: 0: no redundant snapshots, 1: rm process started, negative: error
 336  */
 337 static struct snapshot *find_redundant_snapshot(struct snapshot_list *sl)
 338 {
 339         int i, interval;
 340         struct snapshot *s;
 341         unsigned missing = 0;
 342
 343         DSS_DEBUG_LOG("looking for intervals containing too many snapshots\n");
 344         for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
 345                 unsigned keep = desired_number_of_snapshots(interval, conf.num_intervals_arg);
 346                 unsigned num = sl->interval_count[interval];
 347                 struct snapshot *victim = NULL, *prev = NULL;
 348                 int64_t score = LONG_MAX;
 349
 350                 if (keep >= num)
 351                         missing += keep - num;
 352 //              DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
 353 //                      interval, keep, num, missing);
 354                 if (keep + missing >= num)
 355                         continue;
 356                 /* redundant snapshot in this interval, pick snapshot with lowest score */
 357                 FOR_EACH_SNAPSHOT(s, i, sl) {
 358                         int64_t this_score;
 359
 360                         if (snapshot_is_being_created(s))
 361                                 continue;
 362                         if (is_reference_snapshot(s))
 363                                 continue;
 364                         //DSS_DEBUG_LOG("checking %s\n", s->name);
 365                         if (s->interval > interval) {
 366                                 prev = s;
 367                                 continue;
 368                         }
 369                         if (s->interval < interval)
 370                                 break;
 371                         if (!victim) {
 372                                 victim = s;
 373                                 prev = s;
 374                                 continue;
 375                         }
 376                         assert(prev);
 377                         /* check if s is a better victim */
 378                         this_score = s->creation_time - prev->creation_time;
 379                         assert(this_score >= 0);
 380                         //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
 381                         if (this_score < score) {
 382                                 score = this_score;
 383                                 victim = s;
 384                         }
 385                         prev = s;
 386                 }
 387                 assert(victim);
 388                 return victim;
 389         }
 390         return NULL;
 391 }
 392
 393 static struct snapshot *find_outdated_snapshot(struct snapshot_list *sl)
 394 {
 395         int i;
 396         struct snapshot *s;
 397
 398         DSS_DEBUG_LOG("looking for snapshots belonging to intervals >= %d\n",
 399                 conf.num_intervals_arg);
 400         FOR_EACH_SNAPSHOT(s, i, sl) {
 401                 if (snapshot_is_being_created(s))
 402                         continue;
 403                 if (is_reference_snapshot(s))
 404                         continue;
 405                 if (s->interval < conf.num_intervals_arg)
 406                         continue;
 407                 return s;
 408         }
 409         return NULL;
 410 }
 411
 412 struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
 413 {
 414         int i;
 415         struct snapshot *s;
 416         FOR_EACH_SNAPSHOT(s, i, sl) {
 417                 if (snapshot_is_being_created(s))
 418                         continue;
 419                 if (is_reference_snapshot(s))
 420                         continue;
 421                 DSS_INFO_LOG("oldest removable snapshot: %s\n", s->name);
 422                 return s;
 423         }
 424         return NULL;
 425 }
 426
 427 static int rename_incomplete_snapshot(int64_t start)
 428 {
 429         char *old_name;
 430         int ret;
 431
 432         free(path_to_last_complete_snapshot);
 433         ret = complete_name(start, get_current_time(),
 434                 &path_to_last_complete_snapshot);
 435         if (ret < 0)
 436                 return ret;
 437         old_name = incomplete_name(start);
 438         ret = dss_rename(old_name, path_to_last_complete_snapshot);
 439         if (ret >= 0)
 440                 DSS_NOTICE_LOG("%s -> %s\n", old_name,
 441                         path_to_last_complete_snapshot);
 442         free(old_name);
 443         return ret;
 444 }
 445
 446 static int try_to_free_disk_space(void)
 447 {
 448         int ret;
 449         struct snapshot_list sl;
 450         struct snapshot *victim;
 451         struct timeval now;
 452         const char *why;
 453         int low_disk_space;
 454
 455         ret = disk_space_low();
 456         if (ret < 0)
 457                 return ret;
 458         low_disk_space = ret;
 459         gettimeofday(&now, NULL);
 460         if (tv_diff(&next_removal_check, &now, NULL) > 0)
 461                 return 0;
 462         if (!low_disk_space) {
 463                 if (conf.keep_redundant_given)
 464                         return 0;
 465                 if (snapshot_creation_status != HS_READY)
 466                         return 0;
 467                 if (next_snapshot_is_due())
 468                         return 0;
 469         }
 470         dss_get_snapshot_list(&sl);
 471         ret = 0;
 472         if (!low_disk_space && sl.num_snapshots <= 1)
 473                 goto out;
 474         why = "outdated";
 475         victim = find_outdated_snapshot(&sl);
 476         if (victim)
 477                 goto remove;
 478         why = "redundant";
 479         victim = find_redundant_snapshot(&sl);
 480         if (victim)
 481                 goto remove;
 482         /* try harder only if disk space is low */
 483         if (!low_disk_space)
 484                 goto out;
 485         why = "orphaned";
 486         victim = find_orphaned_snapshot(&sl);
 487         if (victim)
 488                 goto remove;
 489         DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
 490         victim = find_oldest_removable_snapshot(&sl);
 491         if (victim)
 492                 goto remove;
 493         DSS_CRIT_LOG("uhuhu: disk space low and nothing to remove\n");
 494         ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
 495         goto out;
 496 remove:
 497         ret = pre_remove_hook(victim, why);
 498 out:
 499         free_snapshot_list(&sl);
 500         return ret;
 501 }
 502
 503 static int post_create_hook(void)
 504 {
 505         int ret, fds[3] = {0, 0, 0};
 506         char *cmd;
 507
 508         if (!conf.post_create_hook_given) {
 509                 create_pid = 0;
 510                 snapshot_creation_status = HS_READY;
 511                 return 0;
 512         }
 513         cmd = make_message("%s %s/%s", conf.post_create_hook_arg,
 514                 conf.dest_dir_arg, path_to_last_complete_snapshot);
 515         DSS_NOTICE_LOG("executing %s\n", cmd);
 516         ret = dss_exec_cmdline_pid(&create_pid, cmd, fds);
 517         free(cmd);
 518         if (ret < 0)
 519                 return ret;
 520         snapshot_creation_status = HS_POST_RUNNING;
 521         return ret;
 522 }
 523
 524 static int post_remove_hook(void)
 525 {
 526         int ret, fds[3] = {0, 0, 0};
 527         char *cmd;
 528         struct snapshot *s = snapshot_currently_being_removed;
 529
 530         assert(s);
 531
 532         if (!conf.post_remove_hook_given) {
 533                 snapshot_removal_status = HS_READY;
 534                 return 0;
 535         }
 536         cmd = make_message("%s %s/%s", conf.post_remove_hook_arg,
 537                 conf.dest_dir_arg, s->name);
 538         DSS_NOTICE_LOG("executing %s\n", cmd);
 539         ret = dss_exec_cmdline_pid(&remove_pid, cmd, fds);
 540         free(cmd);
 541         if (ret < 0)
 542                 return ret;
 543         snapshot_removal_status = HS_POST_RUNNING;
 544         return ret;
 545 }
 546
 547 static void kill_process(pid_t pid)
 548 {
 549         if (!pid)
 550                 return;
 551         DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
 552         kill(pid, SIGTERM);
 553 }
 554
 555 static void stop_create_process(void)
 556 {
 557         if (!create_pid || create_process_stopped)
 558                 return;
 559         kill(SIGSTOP, create_pid);
 560         create_process_stopped = 1;
 561 }
 562
 563 static void restart_create_process(void)
 564 {
 565         if (!create_pid || !create_process_stopped)
 566                 return;
 567         kill (SIGCONT, create_pid);
 568         create_process_stopped = 0;
 569 }
 570
 571 /**
 572  * Print a log message about the exit status of a child.
 573  */
 574 static void log_termination_msg(pid_t pid, int status)
 575 {
 576         if (WIFEXITED(status))
 577                 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
 578                         WEXITSTATUS(status));
 579         else if (WIFSIGNALED(status))
 580                 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
 581                         WTERMSIG(status));
 582         else
 583                 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
 584 }
 585
 586 static int wait_for_process(pid_t pid, int *status)
 587 {
 588         int ret;
 589
 590         DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
 591         for (;;) {
 592                 fd_set rfds;
 593
 594                 FD_ZERO(&rfds);
 595                 FD_SET(signal_pipe, &rfds);
 596                 ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
 597                 if (ret < 0)
 598                         break;
 599                 ret = next_signal();
 600                 if (!ret)
 601                         continue;
 602                 if (ret == SIGCHLD) {
 603                         ret = waitpid(pid, status, 0);
 604                         if (ret >= 0)
 605                                 break;
 606                         if (errno != EINTR) { /* error */
 607                                 ret = -ERRNO_TO_DSS_ERROR(errno);
 608                                 break;
 609                         }
 610                 }
 611                 /* SIGINT or SIGTERM */
 612                 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
 613                 kill(pid, SIGTERM);
 614         }
 615         if (ret < 0)
 616                 DSS_ERROR_LOG("failed to wait for process %d\n", (int)pid);
 617         else
 618                 log_termination_msg(pid, *status);
 619         return ret;
 620 }
 621
 622 static void handle_pre_remove_exit(int status)
 623 {
 624         if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 625                 snapshot_removal_status = HS_READY;
 626                 gettimeofday(&next_removal_check, NULL);
 627                 next_removal_check.tv_sec += 60;
 628                 return;
 629         }
 630         snapshot_removal_status = HS_PRE_SUCCESS;
 631 }
 632
 633 static int handle_rm_exit(int status)
 634 {
 635         if (!WIFEXITED(status)) {
 636                 snapshot_removal_status = HS_READY;
 637                 return -E_INVOLUNTARY_EXIT;
 638         }
 639         if (WEXITSTATUS(status)) {
 640                 snapshot_removal_status = HS_READY;
 641                 return -E_BAD_EXIT_CODE;
 642         }
 643         if (conf.post_remove_hook_given)
 644                 snapshot_removal_status = HS_SUCCESS;
 645         else
 646                 snapshot_removal_status = HS_READY;
 647         return 1;
 648 }
 649
 650 static void handle_post_remove_exit(void)
 651 {
 652         snapshot_removal_status = HS_READY;
 653 }
 654
 655 static int handle_remove_exit(int status)
 656 {
 657         int ret;
 658         struct snapshot *s = snapshot_currently_being_removed;
 659
 660         assert(s);
 661         switch (snapshot_removal_status) {
 662         case HS_PRE_RUNNING:
 663                 handle_pre_remove_exit(status);
 664                 ret = 1;
 665                 break;
 666         case HS_RUNNING:
 667                 ret = handle_rm_exit(status);
 668                 break;
 669         case HS_POST_RUNNING:
 670                 handle_post_remove_exit();
 671                 ret = 1;
 672                 break;
 673         default:
 674                 ret = -E_BUG;
 675         }
 676         if (snapshot_removal_status == HS_READY) {
 677                 free(s->name);
 678                 free(s);
 679                 snapshot_currently_being_removed = NULL;
 680         }
 681         remove_pid = 0;
 682         return ret;
 683 }
 684
 685 static int wait_for_remove_process(void)
 686 {
 687         int status, ret;
 688
 689         assert(remove_pid);
 690         assert(
 691                 snapshot_removal_status == HS_PRE_RUNNING ||
 692                 snapshot_removal_status == HS_RUNNING ||
 693                 snapshot_removal_status == HS_POST_RUNNING
 694         );
 695         ret = wait_for_process(remove_pid, &status);
 696         if (ret < 0)
 697                 return ret;
 698         return handle_remove_exit(status);
 699 }
 700
 701 static int handle_rsync_exit(int status)
 702 {
 703         int es, ret;
 704
 705         if (!WIFEXITED(status)) {
 706                 DSS_ERROR_LOG("rsync process %d died involuntary\n", (int)create_pid);
 707                 ret = -E_INVOLUNTARY_EXIT;
 708                 snapshot_creation_status = HS_READY;
 709                 goto out;
 710         }
 711         es = WEXITSTATUS(status);
 712         /*
 713          * Restart rsync on non-fatal errors:
 714          * 12: Error in rsync protocol data stream
 715          * 13: Errors with program diagnostics
 716          */
 717         if (es == 12 || es == 13) {
 718                 DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
 719                         (int)create_pid, es);
 720                 snapshot_creation_status = HS_NEEDS_RESTART;
 721                 next_snapshot_time = get_current_time() + 60;
 722                 ret = 1;
 723                 goto out;
 724         }
 725         if (es != 0 && es != 23 && es != 24) {
 726                 DSS_ERROR_LOG("rsync process %d returned %d\n", (int)create_pid, es);
 727                 ret = -E_BAD_EXIT_CODE;
 728                 snapshot_creation_status = HS_READY;
 729                 goto out;
 730         }
 731         ret = rename_incomplete_snapshot(current_snapshot_creation_time);
 732         if (ret < 0)
 733                 goto out;
 734         snapshot_creation_status = HS_SUCCESS;
 735         free(name_of_reference_snapshot);
 736         name_of_reference_snapshot = NULL;
 737 out:
 738         create_process_stopped = 0;
 739         return ret;
 740 }
 741
 742 static int handle_pre_create_hook_exit(int status)
 743 {
 744         int es, ret;
 745         static int warn_count;
 746
 747         if (!WIFEXITED(status)) {
 748                 snapshot_creation_status = HS_READY;
 749                 ret = -E_INVOLUNTARY_EXIT;
 750                 goto out;
 751         }
 752         es = WEXITSTATUS(status);
 753         if (es) {
 754                 if (!warn_count--) {
 755                         DSS_NOTICE_LOG("pre_create_hook %s returned %d\n",
 756                                 conf.pre_create_hook_arg, es);
 757                         DSS_NOTICE_LOG("deferring snapshot creation...\n");
 758                         warn_count = 60; /* warn only once per hour */
 759                 }
 760                 next_snapshot_time = get_current_time() + 60;
 761                 snapshot_creation_status = HS_READY;
 762                 ret = 0;
 763                 goto out;
 764         }
 765         warn_count = 0;
 766         snapshot_creation_status = HS_PRE_SUCCESS;
 767         ret = 1;
 768 out:
 769         return ret;
 770 }
 771
 772 static int handle_sigchld(void)
 773 {
 774         pid_t pid;
 775         int status, ret = reap_child(&pid, &status);
 776
 777         if (ret <= 0)
 778                 return ret;
 779
 780         if (pid == create_pid) {
 781                 switch (snapshot_creation_status) {
 782                 case HS_PRE_RUNNING:
 783                         return handle_pre_create_hook_exit(status);
 784                 case HS_RUNNING:
 785                         return handle_rsync_exit(status);
 786                 case HS_POST_RUNNING:
 787                         snapshot_creation_status = HS_READY;
 788                         return 1;
 789                 default:
 790                         DSS_EMERG_LOG("BUG: create can't die in status %d\n",
 791                                 snapshot_creation_status);
 792                         return -E_BUG;
 793                 }
 794                 create_pid = 0;
 795         }
 796         if (pid == remove_pid) {
 797                 ret = handle_remove_exit(status);
 798                 if (ret < 0)
 799                         return ret;
 800                 return ret;
 801         }
 802         DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
 803         return -E_BUG;
 804 }
 805
 806 static int check_config(void)
 807 {
 808         if (conf.unit_interval_arg <= 0) {
 809                 DSS_ERROR_LOG("bad unit interval: %i\n", conf.unit_interval_arg);
 810                 return -E_INVALID_NUMBER;
 811         }
 812         DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
 813         if (conf.num_intervals_arg <= 0) {
 814                 DSS_ERROR_LOG("bad number of intervals  %i\n", conf.num_intervals_arg);
 815                 return -E_INVALID_NUMBER;
 816         }
 817         DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
 818         return 1;
 819 }
 820
 821 /*
 822  * Returns < 0 on errors, 0 if no config file is given and > 0 if the config
 823  * file was read successfully.
 824  */
 825 static int parse_config_file(int override)
 826 {
 827         int ret, config_file_exists;
 828         char *config_file;
 829         struct stat statbuf;
 830         char *old_logfile_arg = NULL;
 831         int old_daemon_given = 0;
 832
 833         if (conf.config_file_given)
 834                 config_file = dss_strdup(conf.config_file_arg);
 835         else {
 836                 char *home = get_homedir();
 837                 config_file = make_message("%s/.dssrc", home);
 838                 free(home);
 839         }
 840         if (override) { /* SIGHUP */
 841                 if (conf.logfile_given)
 842                         old_logfile_arg = dss_strdup(conf.logfile_arg);
 843                 old_daemon_given = conf.daemon_given;
 844         }
 845
 846         config_file_exists = !stat(config_file, &statbuf);
 847         if (!config_file_exists && conf.config_file_given) {
 848                 ret = -ERRNO_TO_DSS_ERROR(errno);
 849                 DSS_ERROR_LOG("failed to stat config file %s\n", config_file);
 850                 goto out;
 851         }
 852         if (config_file_exists) {
 853                 struct cmdline_parser_params params = {
 854                         .override = override,
 855                         .initialize = 0,
 856                         .check_required = 1,
 857                         .check_ambiguity = 0,
 858                         .print_errors = 1
 859                 };
 860                 if (override) { /* invalidate all rsync options */
 861                         int i;
 862
 863                         for (i = 0; i < conf.rsync_option_given; i++) {
 864                                 free(conf.rsync_option_arg[i]);
 865                                 conf.rsync_option_arg[i] = NULL;
 866                         }
 867                         conf.rsync_option_given = 0;
 868                 }
 869                 cmdline_parser_config_file(config_file, &conf, &params);
 870         }
 871         ret = check_config();
 872         if (ret < 0)
 873                 goto out;
 874         if (override) {
 875                 /* don't change daemon mode on SIGHUP */
 876                 conf.daemon_given = old_daemon_given;
 877                 close_log(logfile);
 878                 logfile = NULL;
 879                 if (conf.logfile_given)
 880                         free(old_logfile_arg);
 881                 else if (conf.daemon_given) { /* re-use old logfile */
 882                         conf.logfile_arg = old_logfile_arg;
 883                         conf.logfile_given = 1;
 884                 }
 885         }
 886         if (conf.logfile_given) {
 887                 logfile = open_log(conf.logfile_arg);
 888                 log_welcome(conf.loglevel_arg);
 889         }
 890         DSS_DEBUG_LOG("loglevel: %d\n", conf.loglevel_arg);
 891         ret = config_file_exists;
 892 out:
 893         free(config_file);
 894         if (ret < 0)
 895                 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
 896         return ret;
 897 }
 898
 899 static int change_to_dest_dir(void)
 900 {
 901         DSS_INFO_LOG("changing cwd to %s\n", conf.dest_dir_arg);
 902         return dss_chdir(conf.dest_dir_arg);
 903 }
 904
 905 static void dump_dss_config(const char *msg)
 906 {
 907         if (conf.loglevel_arg > INFO)
 908                 return;
 909         DSS_INFO_LOG("%s\n", msg);
 910         cmdline_parser_dump(logfile? logfile : stderr, &conf);
 911 }
 912
 913 static int handle_sighup(void)
 914 {
 915         int ret;
 916
 917         DSS_NOTICE_LOG("SIGHUP, re-reading config\n");
 918         dump_dss_config("current config");
 919         ret = parse_config_file(1);
 920         if (ret < 0)
 921                 return ret;
 922         dump_dss_config("new config");
 923         invalidate_next_snapshot_time();
 924         return change_to_dest_dir();
 925 }
 926
 927 static int handle_signal(void)
 928 {
 929         int sig, ret = next_signal();
 930
 931         if (ret <= 0)
 932                 goto out;
 933         sig = ret;
 934         switch (sig) {
 935         case SIGINT:
 936         case SIGTERM:
 937                 restart_create_process();
 938                 kill_process(create_pid);
 939                 kill_process(remove_pid);
 940                 ret = -E_SIGNAL;
 941                 break;
 942         case SIGHUP:
 943                 ret = handle_sighup();
 944                 break;
 945         case SIGCHLD:
 946                 ret = handle_sigchld();
 947                 break;
 948         }
 949 out:
 950         if (ret < 0)
 951                 DSS_ERROR_LOG("%s\n", dss_strerror(-ret));
 952         return ret;
 953 }
 954
 955 /*
 956  * We can not use rsync locally if the local user is different from the remote
 957  * user or if the src dir is not on the local host (or both).
 958  */
 959 static int use_rsync_locally(char *logname)
 960 {
 961         char *h = conf.remote_host_arg;
 962
 963         if (strcmp(h, "localhost") && strcmp(h, "127.0.0.1"))
 964                 return 0;
 965         if (conf.remote_user_given && strcmp(conf.remote_user_arg, logname))
 966                 return 0;
 967         return 1;
 968 }
 969
 970 static int rename_resume_snap(int64_t creation_time)
 971 {
 972         struct snapshot_list sl = {.num_snapshots = 0};
 973         struct snapshot *s;
 974         char *new_name = incomplete_name(creation_time);
 975         int ret;
 976
 977         ret = 0;
 978         if (conf.no_resume_given)
 979                 goto out;
 980         dss_get_snapshot_list(&sl);
 981         s = get_newest_snapshot(&sl);
 982         if (!s)
 983                 goto out;
 984         if ((s->flags & SS_COMPLETE) != 0) /* complete */
 985                 goto out;
 986         DSS_INFO_LOG("resuming: reusing %s as destination dir\n", s->name);
 987         ret = dss_rename(s->name, new_name);
 988 out:
 989         if (ret >= 0)
 990                 DSS_NOTICE_LOG("creating new snapshot %s\n", new_name);
 991         free(new_name);
 992         free_snapshot_list(&sl);
 993         return ret;
 994 }
 995
 996 static void create_rsync_argv(char ***argv, int64_t *num)
 997 {
 998         char *logname;
 999         int i = 0, j;
1000         struct snapshot_list sl;
1001
1002         dss_get_snapshot_list(&sl);
1003         assert(!name_of_reference_snapshot);
1004         name_of_reference_snapshot = name_of_newest_complete_snapshot(&sl);
1005         free_snapshot_list(&sl);
1006
1007         *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
1008         (*argv)[i++] = dss_strdup("rsync");
1009         (*argv)[i++] = dss_strdup("-aq");
1010         (*argv)[i++] = dss_strdup("--delete");
1011         for (j = 0; j < conf.rsync_option_given; j++)
1012                 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
1013         if (name_of_reference_snapshot) {
1014                 DSS_INFO_LOG("using %s as reference\n", name_of_reference_snapshot);
1015                 (*argv)[i++] = make_message("--link-dest=../%s",
1016                         name_of_reference_snapshot);
1017         } else
1018                 DSS_INFO_LOG("no suitable reference snapshot found\n");
1019         logname = dss_logname();
1020         if (use_rsync_locally(logname))
1021                 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
1022         else
1023                 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
1024                         conf.remote_user_arg : logname,
1025                         conf.remote_host_arg, conf.source_dir_arg);
1026         free(logname);
1027         *num = get_current_time();
1028         (*argv)[i++] = incomplete_name(*num);
1029         (*argv)[i++] = NULL;
1030         for (j = 0; j < i; j++)
1031                 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
1032 }
1033
1034 static void free_rsync_argv(char **argv)
1035 {
1036         int i;
1037
1038         if (!argv)
1039                 return;
1040         for (i = 0; argv[i]; i++)
1041                 free(argv[i]);
1042         free(argv);
1043 }
1044
1045 static int create_snapshot(char **argv)
1046 {
1047         int ret, fds[3] = {0, 0, 0};
1048
1049         ret = rename_resume_snap(current_snapshot_creation_time);
1050         if (ret < 0)
1051                 return ret;
1052         ret = dss_exec(&create_pid, argv[0], argv, fds);
1053         if (ret < 0)
1054                 return ret;
1055         snapshot_creation_status = HS_RUNNING;
1056         return ret;
1057 }
1058
1059 static int select_loop(void)
1060 {
1061         int ret;
1062         /* check every 60 seconds for free disk space */
1063         struct timeval tv;
1064         char **rsync_argv = NULL;
1065
1066         for (;;) {
1067                 fd_set rfds;
1068                 struct timeval *tvp;
1069
1070                 if (remove_pid)
1071                         tvp = NULL; /* sleep until rm hook/process dies */
1072                 else { /* sleep one minute */
1073                         tv.tv_sec = 60;
1074                         tv.tv_usec = 0;
1075                         tvp = &tv;
1076                 }
1077                 FD_ZERO(&rfds);
1078                 FD_SET(signal_pipe, &rfds);
1079                 DSS_DEBUG_LOG("tvp: %p, tv_sec : %lu\n", tvp, (long unsigned) tv.tv_sec);
1080                 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
1081                 if (ret < 0)
1082                         goto out;
1083                 if (FD_ISSET(signal_pipe, &rfds)) {
1084                         ret = handle_signal();
1085                         if (ret < 0)
1086                                 goto out;
1087                 }
1088                 if (remove_pid)
1089                         continue;
1090                 if (snapshot_removal_status == HS_PRE_SUCCESS) {
1091                         ret = exec_rm();
1092                         if (ret < 0)
1093                                 goto out;
1094                         continue;
1095                 }
1096                 if (snapshot_removal_status == HS_SUCCESS) {
1097                         ret = post_remove_hook();
1098                         if (ret < 0)
1099                                 goto out;
1100                         continue;
1101                 }
1102                 ret = try_to_free_disk_space();
1103                 if (ret < 0)
1104                         goto out;
1105                 if (snapshot_removal_status != HS_READY) {
1106                         stop_create_process();
1107                         continue;
1108                 }
1109                 restart_create_process();
1110                 switch (snapshot_creation_status) {
1111                 case HS_READY:
1112                         if (!next_snapshot_is_due())
1113                                 continue;
1114                         ret = pre_create_hook();
1115                         if (ret < 0)
1116                                 goto out;
1117                         continue;
1118                 case HS_PRE_RUNNING:
1119                 case HS_RUNNING:
1120                 case HS_POST_RUNNING:
1121                         continue;
1122                 case HS_PRE_SUCCESS:
1123                         free_rsync_argv(rsync_argv);
1124                         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1125                         /* fall through */
1126                 case HS_NEEDS_RESTART:
1127                         ret = create_snapshot(rsync_argv);
1128                         if (ret < 0)
1129                                 goto out;
1130                         continue;
1131                 case HS_SUCCESS:
1132                         ret = post_create_hook();
1133                         if (ret < 0)
1134                                 goto out;
1135                         continue;
1136                 }
1137         }
1138 out:
1139         return ret;
1140 }
1141
1142 static void exit_hook(int exit_code)
1143 {
1144         int fds[3] = {0, 0, 0};
1145         char *argv[] = {conf.exit_hook_arg, dss_strerror(-exit_code), NULL};
1146         pid_t pid;
1147
1148         if (!conf.exit_hook_given)
1149                 return;
1150         DSS_NOTICE_LOG("executing %s %s\n", argv[0], argv[1]);
1151         dss_exec(&pid, conf.exit_hook_arg, argv, fds);
1152 }
1153
1154 static int com_run(void)
1155 {
1156         int ret;
1157
1158         if (conf.dry_run_given) {
1159                 DSS_ERROR_LOG("dry_run not supported by this command\n");
1160                 return -E_SYNTAX;
1161         }
1162         ret = install_sighandler(SIGHUP);
1163         if (ret < 0)
1164                 return ret;
1165         ret = select_loop();
1166         if (ret >= 0) /* impossible */
1167                 ret = -E_BUG;
1168         exit_hook(ret);
1169         return ret;
1170 }
1171
1172 static int com_prune(void)
1173 {
1174         int ret;
1175         struct snapshot_list sl;
1176         struct snapshot *victim;
1177         struct disk_space ds;
1178         const char *why;
1179
1180         ret = get_disk_space(".", &ds);
1181         if (ret < 0)
1182                 return ret;
1183         log_disk_space(&ds);
1184         dss_get_snapshot_list(&sl);
1185         why = "outdated";
1186         victim = find_outdated_snapshot(&sl);
1187         if (victim)
1188                 goto rm;
1189         why = "redundant";
1190         victim = find_redundant_snapshot(&sl);
1191         if (victim)
1192                 goto rm;
1193         ret = 0;
1194         goto out;
1195 rm:
1196         if (conf.dry_run_given) {
1197                 dss_msg("%s snapshot %s (interval = %i)\n",
1198                         why, victim->name, victim->interval);
1199                 ret = 0;
1200                 goto out;
1201         }
1202         ret = pre_remove_hook(victim, why);
1203         if (ret < 0)
1204                 goto out;
1205         if (snapshot_removal_status == HS_PRE_RUNNING) {
1206                 ret = wait_for_remove_process();
1207                 if (ret < 0)
1208                         goto out;
1209                 if (snapshot_removal_status != HS_PRE_SUCCESS)
1210                         goto out;
1211         }
1212         ret = exec_rm();
1213         if (ret < 0)
1214                 goto out;
1215         ret = wait_for_remove_process();
1216         if (ret < 0)
1217                 goto out;
1218         if (snapshot_removal_status != HS_SUCCESS)
1219                 goto out;
1220         ret = post_remove_hook();
1221         if (ret < 0)
1222                 goto out;
1223         if (snapshot_removal_status != HS_POST_RUNNING)
1224                 goto out;
1225         ret = wait_for_remove_process();
1226         if (ret < 0)
1227                 goto out;
1228         ret = 1;
1229 out:
1230         free_snapshot_list(&sl);
1231         return ret;
1232 }
1233
1234 static int com_create(void)
1235 {
1236         int ret, status;
1237         char **rsync_argv;
1238
1239         if (conf.dry_run_given) {
1240                 int i;
1241                 char *msg = NULL;
1242                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1243                 for (i = 0; rsync_argv[i]; i++) {
1244                         char *tmp = msg;
1245                         msg = make_message("%s%s%s", tmp? tmp : "",
1246                                 tmp? " " : "", rsync_argv[i]);
1247                         free(tmp);
1248                 }
1249                 free_rsync_argv(rsync_argv);
1250                 dss_msg("%s\n", msg);
1251                 free(msg);
1252                 return 1;
1253         }
1254         ret = pre_create_hook();
1255         if (ret < 0)
1256                 return ret;
1257         if (create_pid) {
1258                 ret = wait_for_process(create_pid, &status);
1259                 if (ret < 0)
1260                         return ret;
1261                 ret = handle_pre_create_hook_exit(status);
1262                 if (ret <= 0) /* error, or pre-create failed */
1263                         return ret;
1264         }
1265         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1266         ret = create_snapshot(rsync_argv);
1267         if (ret < 0)
1268                 goto out;
1269         ret = wait_for_process(create_pid, &status);
1270         if (ret < 0)
1271                 goto out;
1272         ret = handle_rsync_exit(status);
1273         if (ret < 0)
1274                 goto out;
1275         post_create_hook();
1276         if (create_pid)
1277                 ret = wait_for_process(create_pid, &status);
1278 out:
1279         free_rsync_argv(rsync_argv);
1280         return ret;
1281 }
1282
1283 static int com_ls(void)
1284 {
1285         int i;
1286         struct snapshot_list sl;
1287         struct snapshot *s;
1288
1289         dss_get_snapshot_list(&sl);
1290         FOR_EACH_SNAPSHOT(s, i, &sl) {
1291                 int64_t d = 0;
1292                 if (s->flags & SS_COMPLETE)
1293                         d = (s->completion_time - s->creation_time) / 60;
1294                 dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
1295         };
1296         free_snapshot_list(&sl);
1297         return 1;
1298 }
1299
1300 static int setup_signal_handling(void)
1301 {
1302         int ret;
1303
1304         DSS_INFO_LOG("setting up signal handlers\n");
1305         signal_pipe = signal_init(); /* always successful */
1306         ret = install_sighandler(SIGINT);
1307         if (ret < 0)
1308                 return ret;
1309         ret = install_sighandler(SIGTERM);
1310         if (ret < 0)
1311                 return ret;
1312         return install_sighandler(SIGCHLD);
1313 }
1314
1315 /**
1316  * The main function of dss.
1317  *
1318  * \param argc Usual argument count.
1319  * \param argv Usual argument vector.
1320  */
1321 int main(int argc, char **argv)
1322 {
1323         int ret;
1324         struct cmdline_parser_params params = {
1325                 .override = 0,
1326                 .initialize = 1,
1327                 .check_required = 0,
1328                 .check_ambiguity = 0,
1329                 .print_errors = 1
1330         };
1331
1332         cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1333         ret = parse_config_file(0);
1334         if (ret < 0)
1335                 goto out;
1336         if (ret == 0) { /* no config file given */
1337                 /*
1338                  * Parse the command line options again, but this time check
1339                  * that all required options are given.
1340                  */
1341                 params = (struct cmdline_parser_params) {
1342                         .override = 1,
1343                         .initialize = 1,
1344                         .check_required = 1,
1345                         .check_ambiguity = 1,
1346                         .print_errors = 1
1347                 };
1348                 cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1349         }
1350         if (conf.daemon_given)
1351                 daemon_init();
1352         dump_dss_config("dss configuration");
1353         ret = change_to_dest_dir();
1354         if (ret < 0)
1355                 goto out;
1356         ret = setup_signal_handling();
1357         if (ret < 0)
1358                 goto out;
1359         ret = call_command_handler();
1360 out:
1361         if (ret < 0)
1362                 DSS_EMERG_LOG("%s\n", dss_strerror(-ret));
1363         exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1364 }