git.ozlabs.org Git - ccan/blob - ccan/tdb/tools/replay_trace.c

   1 #include <ccan/tdb/tdb.h>
   2 #include <ccan/grab_file/grab_file.h>
   3 #include <ccan/hash/hash.h>
   4 #include <ccan/talloc/talloc.h>
   5 #include <ccan/str_talloc/str_talloc.h>
   6 #include <ccan/str/str.h>
   7 #include <ccan/list/list.h>
   8 #include <err.h>
   9 #include <ctype.h>
  10 #include <string.h>
  11 #include <unistd.h>
  12 #include <sys/types.h>
  13 #include <sys/wait.h>
  14 #include <sys/time.h>
  15 #include <errno.h>
  16 #include <signal.h>
  17 #include <assert.h>
  18
  19 #define STRINGIFY2(x) #x
  20 #define STRINGIFY(x) STRINGIFY2(x)
  21
  22 /* Avoid mod by zero */
  23 static unsigned int total_keys = 1;
  24
  25 /* #define DEBUG_DEPS 1 */
  26
  27 /* Traversals block transactions in the current implementation. */
  28 #define TRAVERSALS_TAKE_TRANSACTION_LOCK 1
  29
  30 struct pipe {
  31         int fd[2];
  32 };
  33 static struct pipe *pipes;
  34
  35 static void __attribute__((noreturn)) fail(const char *filename,
  36                                            unsigned int line,
  37                                            const char *fmt, ...)
  38 {
  39         va_list ap;
  40
  41         va_start(ap, fmt);
  42         fprintf(stderr, "%s:%u: FAIL: ", filename, line);
  43         vfprintf(stderr, fmt, ap);
  44         fprintf(stderr, "\n");
  45         va_end(ap);
  46         exit(1);
  47 }
  48
  49 /* Try or die. */
  50 #define try(expr, expect)                                               \
  51         do {                                                            \
  52                 int ret = (expr);                                       \
  53                 if (ret != (expect))                                    \
  54                         fail(filename[file], i+1,                       \
  55                              STRINGIFY(expr) "= %i", ret);              \
  56         } while (0)
  57
  58 /* Try or imitate results. */
  59 #define unreliable(expr, expect, force, undo)                           \
  60         do {                                                            \
  61                 int ret = expr;                                         \
  62                 if (ret != expect) {                                    \
  63                         fprintf(stderr, "%s:%u: %s gave %i not %i",     \
  64                                 filename[file], i+1, STRINGIFY(expr),   \
  65                                 ret, expect);                           \
  66                         if (expect == 0)                                \
  67                                 force;                                  \
  68                         else                                            \
  69                                 undo;                                   \
  70                 }                                                       \
  71         } while (0)
  72
  73 static bool key_eq(TDB_DATA a, TDB_DATA b)
  74 {
  75         if (a.dsize != b.dsize)
  76                 return false;
  77         return memcmp(a.dptr, b.dptr, a.dsize) == 0;
  78 }
  79
  80 /* This is based on the hash algorithm from gdbm */
  81 static unsigned int hash_key(TDB_DATA *key)
  82 {
  83         uint32_t value; /* Used to compute the hash value.  */
  84         uint32_t   i;   /* Used to cycle through random values. */
  85
  86         /* Set the initial value from the key size. */
  87         for (value = 0x238F13AF ^ key->dsize, i=0; i < key->dsize; i++)
  88                 value = (value + (key->dptr[i] << (i*5 % 24)));
  89
  90         return (1103515243 * value + 12345);
  91 }
  92
  93 enum op_type {
  94         OP_TDB_LOCKALL,
  95         OP_TDB_LOCKALL_MARK,
  96         OP_TDB_LOCKALL_UNMARK,
  97         OP_TDB_LOCKALL_NONBLOCK,
  98         OP_TDB_UNLOCKALL,
  99         OP_TDB_LOCKALL_READ,
 100         OP_TDB_LOCKALL_READ_NONBLOCK,
 101         OP_TDB_UNLOCKALL_READ,
 102         OP_TDB_CHAINLOCK,
 103         OP_TDB_CHAINLOCK_NONBLOCK,
 104         OP_TDB_CHAINLOCK_MARK,
 105         OP_TDB_CHAINLOCK_UNMARK,
 106         OP_TDB_CHAINUNLOCK,
 107         OP_TDB_CHAINLOCK_READ,
 108         OP_TDB_CHAINUNLOCK_READ,
 109         OP_TDB_PARSE_RECORD,
 110         OP_TDB_EXISTS,
 111         OP_TDB_STORE,
 112         OP_TDB_APPEND,
 113         OP_TDB_GET_SEQNUM,
 114         OP_TDB_WIPE_ALL,
 115         OP_TDB_TRANSACTION_START,
 116         OP_TDB_TRANSACTION_CANCEL,
 117         OP_TDB_TRANSACTION_COMMIT,
 118         OP_TDB_TRAVERSE_READ_START,
 119         OP_TDB_TRAVERSE_START,
 120         OP_TDB_TRAVERSE_END,
 121         OP_TDB_TRAVERSE,
 122         OP_TDB_FIRSTKEY,
 123         OP_TDB_NEXTKEY,
 124         OP_TDB_FETCH,
 125         OP_TDB_DELETE,
 126 };
 127
 128 struct op {
 129         unsigned int serial;
 130         enum op_type op;
 131         TDB_DATA key;
 132         TDB_DATA data;
 133         int ret;
 134
 135         /* Who is waiting for us? */
 136         struct list_head post;
 137         /* What are we waiting for? */
 138         struct list_head pre;
 139
 140         /* If I'm part of a group (traverse/transaction) where is
 141          * start?  (Otherwise, 0) */
 142         unsigned int group_start;
 143
 144         union {
 145                 int flag; /* open and store */
 146                 struct {  /* append */
 147                         TDB_DATA pre;
 148                         TDB_DATA post;
 149                 } append;
 150                 unsigned int group_len; /* transaction/traverse start */
 151         };
 152 };
 153
 154 static unsigned char hex_char(const char *filename, unsigned int line, char c)
 155 {
 156         c = toupper(c);
 157         if (c >= 'A' && c <= 'F')
 158                 return c - 'A' + 10;
 159         if (c >= '0' && c <= '9')
 160                 return c - '0';
 161         fail(filename, line, "invalid hex character '%c'", c);
 162 }
 163
 164 /* TDB data is <size>:<%02x>* */
 165 static TDB_DATA make_tdb_data(const void *ctx,
 166                               const char *filename, unsigned int line,
 167                               const char *word)
 168 {
 169         TDB_DATA data;
 170         unsigned int i;
 171         const char *p;
 172
 173         if (streq(word, "NULL"))
 174                 return tdb_null;
 175
 176         data.dsize = atoi(word);
 177         data.dptr = talloc_array(ctx, unsigned char, data.dsize);
 178         p = strchr(word, ':');
 179         if (!p)
 180                 fail(filename, line, "invalid tdb data '%s'", word);
 181         p++;
 182         for (i = 0; i < data.dsize; i++)
 183                 data.dptr[i] = hex_char(filename, line, p[i*2])*16
 184                         + hex_char(filename, line, p[i*2+1]);
 185
 186         return data;
 187 }
 188
 189 static void add_op(const char *filename, struct op **op, unsigned int i,
 190                    unsigned int serial, enum op_type type)
 191 {
 192         struct op *new;
 193         *op = talloc_realloc(NULL, *op, struct op, i+1);
 194         new = (*op) + i;
 195         new->op = type;
 196         new->serial = serial;
 197         new->ret = 0;
 198         new->group_start = 0;
 199 }
 200
 201 static void op_add_nothing(const char *filename,
 202                            struct op op[], unsigned int op_num, char *words[])
 203 {
 204         if (words[2])
 205                 fail(filename, op_num+1, "Expected no arguments");
 206         op[op_num].key = tdb_null;
 207 }
 208
 209 static void op_add_key(const char *filename,
 210                        struct op op[], unsigned int op_num, char *words[])
 211 {
 212         if (words[2] == NULL || words[3])
 213                 fail(filename, op_num+1, "Expected just a key");
 214
 215         op[op_num].key = make_tdb_data(op, filename, op_num+1, words[2]);
 216         if (op[op_num].op != OP_TDB_TRAVERSE)
 217                 total_keys++;
 218 }
 219
 220 static void op_add_key_ret(const char *filename,
 221                            struct op op[], unsigned int op_num, char *words[])
 222 {
 223         if (!words[2] || !words[3] || !words[4] || words[5]
 224             || !streq(words[3], "="))
 225                 fail(filename, op_num+1, "Expected <key> = <ret>");
 226         op[op_num].ret = atoi(words[4]);
 227         op[op_num].key = make_tdb_data(op, filename, op_num+1, words[2]);
 228         /* May only be a unique key if it fails */
 229         if (op[op_num].ret != 0)
 230                 total_keys++;
 231 }
 232
 233 static void op_add_key_data(const char *filename,
 234                             struct op op[], unsigned int op_num, char *words[])
 235 {
 236         if (!words[2] || !words[3] || !words[4] || words[5]
 237             || !streq(words[3], "="))
 238                 fail(filename, op_num+1, "Expected <key> = <data>");
 239         op[op_num].key = make_tdb_data(op, filename, op_num+1, words[2]);
 240         op[op_num].data = make_tdb_data(op, filename, op_num+1, words[4]);
 241         /* May only be a unique key if it fails */
 242         if (!op[op_num].data.dptr)
 243                 total_keys++;
 244 }
 245
 246 /* <serial> tdb_store <rec> <rec> <flag> = <ret> */
 247 static void op_add_store(const char *filename,
 248                          struct op op[], unsigned int op_num, char *words[])
 249 {
 250         if (!words[2] || !words[3] || !words[4] || !words[5] || !words[6]
 251             || words[7] || !streq(words[5], "="))
 252                 fail(filename, op_num+1, "Expect <key> <data> <flag> = <ret>");
 253
 254         op[op_num].flag = strtoul(words[4], NULL, 0);
 255         op[op_num].ret = atoi(words[6]);
 256         op[op_num].key = make_tdb_data(op, filename, op_num+1, words[2]);
 257         op[op_num].data = make_tdb_data(op, filename, op_num+1, words[3]);
 258         total_keys++;
 259 }
 260
 261 /* <serial> tdb_append <rec> <rec> = <rec> */
 262 static void op_add_append(const char *filename,
 263                           struct op op[], unsigned int op_num, char *words[])
 264 {
 265         if (!words[2] || !words[3] || !words[4] || !words[5] || words[6]
 266             || !streq(words[4], "="))
 267                 fail(filename, op_num+1, "Expect <key> <data> = <rec>");
 268
 269         op[op_num].key = make_tdb_data(op, filename, op_num+1, words[2]);
 270         op[op_num].data = make_tdb_data(op, filename, op_num+1, words[3]);
 271
 272         op[op_num].append.post
 273                 = make_tdb_data(op, filename, op_num+1, words[5]);
 274
 275         /* By subtraction, figure out what previous data was. */
 276         op[op_num].append.pre.dptr = op[op_num].append.post.dptr;
 277         op[op_num].append.pre.dsize
 278                 = op[op_num].append.post.dsize - op[op_num].data.dsize;
 279         total_keys++;
 280 }
 281
 282 /* <serial> tdb_get_seqnum = <ret> */
 283 static void op_add_seqnum(const char *filename,
 284                           struct op op[], unsigned int op_num, char *words[])
 285 {
 286         if (!words[2] || !words[3] || words[4] || !streq(words[2], "="))
 287                 fail(filename, op_num+1, "Expect = <ret>");
 288
 289         op[op_num].key = tdb_null;
 290         op[op_num].ret = atoi(words[3]);
 291 }
 292
 293 static void op_add_traverse(const char *filename,
 294                             struct op op[], unsigned int op_num, char *words[])
 295 {
 296         if (words[2])
 297                 fail(filename, op_num+1, "Expect no arguments");
 298
 299         op[op_num].key = tdb_null;
 300         op[op_num].group_len = 0;
 301 }
 302
 303 static void op_add_transaction(const char *filename, struct op op[],
 304                                unsigned int op_num, char *words[])
 305 {
 306         if (words[2])
 307                 fail(filename, op_num+1, "Expect no arguments");
 308
 309         op[op_num].key = tdb_null;
 310         op[op_num].group_len = 0;
 311 }
 312
 313 static int op_transaction_start(struct op op[], unsigned int op_num)
 314 {
 315         unsigned int i;
 316
 317         for (i = op_num-1; i > 0; i--) {
 318                 if (op[i].op == OP_TDB_TRANSACTION_START && !op[i].group_len)
 319                         return i;
 320         }
 321         return 0;
 322 }
 323
 324 static void op_analyze_transaction(const char *filename,
 325                                    struct op op[], unsigned int op_num,
 326                                    char *words[])
 327 {
 328         unsigned int start, i;
 329
 330         op[op_num].key = tdb_null;
 331
 332         if (words[2])
 333                 fail(filename, op_num+1, "Expect no arguments");
 334
 335         start = op_transaction_start(op, op_num);
 336         if (!start)
 337                 fail(filename, op_num+1, "no transaction start found");
 338
 339         op[start].group_len = op_num - start;
 340
 341         /* This rolls in nested transactions.  I think that's right. */
 342         for (i = start; i <= op_num; i++)
 343                 op[i].group_start = start;
 344 }
 345
 346 struct traverse_hash {
 347         TDB_DATA key;
 348         unsigned int index;
 349 };
 350
 351 static void op_analyze_traverse(const char *filename,
 352                                 struct op op[], unsigned int op_num,
 353                                 char *words[])
 354 {
 355         int i, start;
 356
 357         op[op_num].key = tdb_null;
 358
 359         /* = %u means traverse function terminated. */
 360         if (words[2]) {
 361                 if (!streq(words[2], "=") || !words[3] || words[4])
 362                         fail(filename, op_num+1, "expect = <num>");
 363                 op[op_num].ret = atoi(words[3]);
 364         } else
 365                 op[op_num].ret = 0;
 366
 367         for (i = op_num-1; i >= 0; i--) {
 368                 if (op[i].op != OP_TDB_TRAVERSE_READ_START
 369                     && op[i].op != OP_TDB_TRAVERSE_START)
 370                         continue;
 371                 if (op[i].group_len)
 372                         continue;
 373                 break;
 374         }
 375
 376         if (i < 0)
 377                 fail(filename, op_num+1, "no traversal start found");
 378
 379         start = i;
 380         op[start].group_len = op_num - start;
 381
 382         for (i = start; i <= op_num; i++)
 383                 op[i].group_start = start;
 384 }
 385
 386 /* Keep -Wmissing-declarations happy: */
 387 const struct op_table *
 388 find_keyword (register const char *str, register unsigned int len);
 389
 390 #include "keywords.c"
 391
 392 struct depend {
 393         /* We can have more than one */
 394         struct list_node pre_list;
 395         struct list_node post_list;
 396         unsigned int needs_file;
 397         unsigned int needs_opnum;
 398         unsigned int satisfies_file;
 399         unsigned int satisfies_opnum;
 400 };
 401
 402 static void check_deps(const char *filename, struct op op[], unsigned int num)
 403 {
 404 #ifdef DEBUG_DEPS
 405         unsigned int i;
 406
 407         for (i = 1; i < num; i++)
 408                 if (!list_empty(&op[i].pre))
 409                         fail(filename, i+1, "Still has dependencies");
 410 #endif
 411 }
 412
 413 static void dump_pre(char *filename[], struct op *op[],
 414                      unsigned int file, unsigned int i)
 415 {
 416         struct depend *dep;
 417
 418         printf("%s:%u (%u) still waiting for:\n", filename[file], i+1,
 419                 op[file][i].serial);
 420         list_for_each(&op[file][i].pre, dep, pre_list)
 421                 printf("    %s:%u (%u)\n",
 422                        filename[dep->satisfies_file], dep->satisfies_opnum+1,
 423                        op[dep->satisfies_file][dep->satisfies_opnum].serial);
 424         check_deps(filename[file], op[file], i);
 425 }
 426
 427 /* We simply read/write pointers, since we all are children. */
 428 static bool do_pre(struct tdb_context *tdb,
 429                    char *filename[], struct op *op[],
 430                    unsigned int file, int pre_fd, unsigned int i,
 431                    bool backoff)
 432 {
 433         while (!list_empty(&op[file][i].pre)) {
 434                 struct depend *dep;
 435
 436 #if DEBUG_DEPS
 437                 printf("%s:%u:waiting for pre\n", filename[file], i+1);
 438                 fflush(stdout);
 439 #endif
 440                 if (backoff)
 441                         alarm(2);
 442                 else
 443                         alarm(10);
 444                 while (read(pre_fd, &dep, sizeof(dep)) != sizeof(dep)) {
 445                         if (errno == EINTR) {
 446                                 if (backoff) {
 447                                         warnx("%s:%u:avoiding deadlock",
 448                                               filename[file], i+1);
 449                                         return false;
 450                                 }
 451                                 dump_pre(filename, op, file, i);
 452                                 exit(1);
 453                         } else
 454                                 errx(1, "Reading from pipe");
 455                 }
 456                 alarm(0);
 457
 458 #if DEBUG_DEPS
 459                 printf("%s:%u:got pre %u from %s:%u\n", filename[file], i+1,
 460                        dep->needs_opnum+1, filename[dep->satisfies_file],
 461                        dep->satisfies_opnum+1);
 462                 fflush(stdout);
 463 #endif
 464                 /* This could be any op, not just this one. */
 465                 talloc_free(dep);
 466         }
 467         return true;
 468 }
 469
 470 static void do_post(char *filename[], struct op *op[],
 471                     unsigned int file, unsigned int i)
 472 {
 473         struct depend *dep;
 474
 475         list_for_each(&op[file][i].post, dep, post_list) {
 476 #if DEBUG_DEPS
 477                 printf("%s:%u:sending to file %s:%u\n", filename[file], i+1,
 478                        filename[dep->needs_file], dep->needs_opnum+1);
 479 #endif
 480                 if (write(pipes[dep->needs_file].fd[1], &dep, sizeof(dep))
 481                     != sizeof(dep))
 482                         err(1, "%s:%u failed to tell file %s",
 483                             filename[file], i+1, filename[dep->needs_file]);
 484         }
 485 }
 486
 487 static int get_len(TDB_DATA key, TDB_DATA data, void *private_data)
 488 {
 489         return data.dsize;
 490 }
 491
 492 static unsigned run_ops(struct tdb_context *tdb,
 493                         int pre_fd,
 494                         char *filename[],
 495                         struct op *op[],
 496                         unsigned int file,
 497                         unsigned int start, unsigned int stop,
 498                         bool backoff);
 499
 500 struct traverse_info {
 501         struct op **op;
 502         char **filename;
 503         unsigned file;
 504         int pre_fd;
 505         unsigned int start;
 506         unsigned int i;
 507 };
 508
 509 /* More complex.  Just do whatever's they did at the n'th entry. */
 510 static int nontrivial_traverse(struct tdb_context *tdb,
 511                                TDB_DATA key, TDB_DATA data,
 512                                void *_tinfo)
 513 {
 514         struct traverse_info *tinfo = _tinfo;
 515         unsigned int trav_len = tinfo->op[tinfo->file][tinfo->start].group_len;
 516         bool avoid_deadlock = false;
 517
 518         if (tinfo->i == tinfo->start + trav_len) {
 519                 /* This can happen if traverse expects to be empty. */
 520                 if (trav_len == 1)
 521                         return 1;
 522                 fail(tinfo->filename[tinfo->file], tinfo->start + 1,
 523                      "traverse did not terminate");
 524         }
 525
 526         if (tinfo->op[tinfo->file][tinfo->i].op != OP_TDB_TRAVERSE)
 527                 fail(tinfo->filename[tinfo->file], tinfo->start + 1,
 528                      "%s:%u:traverse terminated early");
 529
 530 #if TRAVERSALS_TAKE_TRANSACTION_LOCK
 531         avoid_deadlock = true;
 532 #endif
 533
 534         /* Run any normal ops. */
 535         tinfo->i = run_ops(tdb, tinfo->pre_fd, tinfo->filename, tinfo->op,
 536                            tinfo->file, tinfo->i+1, tinfo->start + trav_len,
 537                            avoid_deadlock);
 538
 539         /* We backed off, or we hit OP_TDB_TRAVERSE_END. */
 540         if (tinfo->op[tinfo->file][tinfo->i].op != OP_TDB_TRAVERSE)
 541                 return 1;
 542
 543         return 0;
 544 }
 545
 546 static unsigned op_traverse(struct tdb_context *tdb,
 547                             int pre_fd,
 548                             char *filename[],
 549                             unsigned int file,
 550                             int (*traversefn)(struct tdb_context *,
 551                                               tdb_traverse_func, void *),
 552                             struct op *op[],
 553                             unsigned int start)
 554 {
 555         struct traverse_info tinfo = { op, filename, file, pre_fd,
 556                                        start, start+1 };
 557
 558         traversefn(tdb, nontrivial_traverse, &tinfo);
 559
 560         /* Traversing in wrong order can have strange effects: eg. if
 561          * original traverse went A (delete A), B, we might do B
 562          * (delete A).  So if we have ops left over, we do it now. */
 563         while (tinfo.i != start + op[file][start].group_len) {
 564                 if (op[file][tinfo.i].op == OP_TDB_TRAVERSE)
 565                         tinfo.i++;
 566                 else
 567                         tinfo.i = run_ops(tdb, pre_fd, filename, op, file,
 568                                           tinfo.i,
 569                                           start + op[file][start].group_len,
 570                                           false);
 571         }
 572
 573         return tinfo.i;
 574 }
 575
 576 static void break_out(int sig)
 577 {
 578 }
 579
 580 static __attribute__((noinline))
 581 unsigned run_ops(struct tdb_context *tdb,
 582                  int pre_fd,
 583                  char *filename[],
 584                  struct op *op[],
 585                  unsigned int file,
 586                  unsigned int start, unsigned int stop,
 587                  bool backoff)
 588 {
 589         unsigned int i;
 590         struct sigaction sa;
 591
 592         sa.sa_handler = break_out;
 593         sa.sa_flags = 0;
 594
 595         sigaction(SIGALRM, &sa, NULL);
 596         for (i = start; i < stop; i++) {
 597                 if (!do_pre(tdb, filename, op, file, pre_fd, i, backoff))
 598                         return i;
 599
 600                 switch (op[file][i].op) {
 601                 case OP_TDB_LOCKALL:
 602                         try(tdb_lockall(tdb), op[file][i].ret);
 603                         break;
 604                 case OP_TDB_LOCKALL_MARK:
 605                         try(tdb_lockall_mark(tdb), op[file][i].ret);
 606                         break;
 607                 case OP_TDB_LOCKALL_UNMARK:
 608                         try(tdb_lockall_unmark(tdb), op[file][i].ret);
 609                         break;
 610                 case OP_TDB_LOCKALL_NONBLOCK:
 611                         unreliable(tdb_lockall_nonblock(tdb), op[file][i].ret,
 612                                    tdb_lockall(tdb), tdb_unlockall(tdb));
 613                         break;
 614                 case OP_TDB_UNLOCKALL:
 615                         try(tdb_unlockall(tdb), op[file][i].ret);
 616                         break;
 617                 case OP_TDB_LOCKALL_READ:
 618                         try(tdb_lockall_read(tdb), op[file][i].ret);
 619                         break;
 620                 case OP_TDB_LOCKALL_READ_NONBLOCK:
 621                         unreliable(tdb_lockall_read_nonblock(tdb),
 622                                    op[file][i].ret,
 623                                    tdb_lockall_read(tdb),
 624                                    tdb_unlockall_read(tdb));
 625                         break;
 626                 case OP_TDB_UNLOCKALL_READ:
 627                         try(tdb_unlockall_read(tdb), op[file][i].ret);
 628                         break;
 629                 case OP_TDB_CHAINLOCK:
 630                         try(tdb_chainlock(tdb, op[file][i].key),
 631                             op[file][i].ret);
 632                         break;
 633                 case OP_TDB_CHAINLOCK_NONBLOCK:
 634                         unreliable(tdb_chainlock_nonblock(tdb, op[file][i].key),
 635                                    op[file][i].ret,
 636                                    tdb_chainlock(tdb, op[file][i].key),
 637                                    tdb_chainunlock(tdb, op[file][i].key));
 638                         break;
 639                 case OP_TDB_CHAINLOCK_MARK:
 640                         try(tdb_chainlock_mark(tdb, op[file][i].key),
 641                             op[file][i].ret);
 642                         break;
 643                 case OP_TDB_CHAINLOCK_UNMARK:
 644                         try(tdb_chainlock_unmark(tdb, op[file][i].key),
 645                             op[file][i].ret);
 646                         break;
 647                 case OP_TDB_CHAINUNLOCK:
 648                         try(tdb_chainunlock(tdb, op[file][i].key),
 649                             op[file][i].ret);
 650                         break;
 651                 case OP_TDB_CHAINLOCK_READ:
 652                         try(tdb_chainlock_read(tdb, op[file][i].key),
 653                             op[file][i].ret);
 654                         break;
 655                 case OP_TDB_CHAINUNLOCK_READ:
 656                         try(tdb_chainunlock_read(tdb, op[file][i].key),
 657                             op[file][i].ret);
 658                         break;
 659                 case OP_TDB_PARSE_RECORD:
 660                         try(tdb_parse_record(tdb, op[file][i].key, get_len,
 661                                              NULL),
 662                             op[file][i].ret);
 663                         break;
 664                 case OP_TDB_EXISTS:
 665                         try(tdb_exists(tdb, op[file][i].key), op[file][i].ret);
 666                         break;
 667                 case OP_TDB_STORE:
 668                         try(tdb_store(tdb, op[file][i].key, op[file][i].data,
 669                                       op[file][i].flag),
 670                             op[file][i].ret);
 671                         break;
 672                 case OP_TDB_APPEND:
 673                         try(tdb_append(tdb, op[file][i].key, op[file][i].data),
 674                             op[file][i].ret);
 675                         break;
 676                 case OP_TDB_GET_SEQNUM:
 677                         try(tdb_get_seqnum(tdb), op[file][i].ret);
 678                         break;
 679                 case OP_TDB_WIPE_ALL:
 680                         try(tdb_wipe_all(tdb), op[file][i].ret);
 681                         break;
 682                 case OP_TDB_TRANSACTION_START:
 683                         try(tdb_transaction_start(tdb), op[file][i].ret);
 684                         break;
 685                 case OP_TDB_TRANSACTION_CANCEL:
 686                         try(tdb_transaction_cancel(tdb), op[file][i].ret);
 687                         break;
 688                 case OP_TDB_TRANSACTION_COMMIT:
 689                         try(tdb_transaction_commit(tdb), op[file][i].ret);
 690                         break;
 691                 case OP_TDB_TRAVERSE_READ_START:
 692                         i = op_traverse(tdb, pre_fd, filename, file,
 693                                         tdb_traverse_read, op, i);
 694                         break;
 695                 case OP_TDB_TRAVERSE_START:
 696                         i = op_traverse(tdb, pre_fd, filename, file,
 697                                         tdb_traverse, op, i);
 698                         break;
 699                 case OP_TDB_TRAVERSE:
 700                         /* Terminate: we're in a traverse, and we've
 701                          * done our ops. */
 702                         return i;
 703                 case OP_TDB_TRAVERSE_END:
 704                         fail(filename[file], i+1, "unexpected end traverse");
 705                 /* FIXME: These must be treated like traverse. */
 706                 case OP_TDB_FIRSTKEY:
 707                         if (!key_eq(tdb_firstkey(tdb), op[file][i].data))
 708                                 fail(filename[file], i+1, "bad firstkey");
 709                         break;
 710                 case OP_TDB_NEXTKEY:
 711                         if (!key_eq(tdb_nextkey(tdb, op[file][i].key),
 712                                     op[file][i].data))
 713                                 fail(filename[file], i+1, "bad nextkey");
 714                         break;
 715                 case OP_TDB_FETCH: {
 716                         TDB_DATA f = tdb_fetch(tdb, op[file][i].key);
 717                         if (!key_eq(f, op[file][i].data))
 718                                 fail(filename[file], i+1, "bad fetch %u",
 719                                      f.dsize);
 720                         break;
 721                 }
 722                 case OP_TDB_DELETE:
 723                         try(tdb_delete(tdb, op[file][i].key), op[file][i].ret);
 724                         break;
 725                 }
 726                 do_post(filename, op, file, i);
 727         }
 728         return i;
 729 }
 730
 731 /* tdbtorture, in particular, can do a tdb_close with a transaction in
 732  * progress. */
 733 static struct op *maybe_cancel_transaction(const char *filename,
 734                                            struct op *op, unsigned int *num)
 735 {
 736         unsigned int start = op_transaction_start(op, *num);
 737
 738         if (start) {
 739                 char *words[] = { "<unknown>", "tdb_close", NULL };
 740                 add_op(filename, &op, *num, op[start].serial,
 741                        OP_TDB_TRANSACTION_CANCEL);
 742                 op_analyze_transaction(filename, op, *num, words);
 743                 (*num)++;
 744         }
 745         return op;
 746 }
 747
 748 static struct op *load_tracefile(const char *filename, unsigned int *num,
 749                                  unsigned int *hashsize,
 750                                  unsigned int *tdb_flags,
 751                                  unsigned int *open_flags)
 752 {
 753         unsigned int i;
 754         struct op *op = talloc_array(NULL, struct op, 1);
 755         char **words;
 756         char **lines;
 757         char *file;
 758
 759         file = grab_file(NULL, filename, NULL);
 760         if (!file)
 761                 err(1, "Reading %s", filename);
 762
 763         lines = strsplit(file, file, "\n", NULL);
 764         if (!lines[0])
 765                 errx(1, "%s is empty", filename);
 766
 767         words = strsplit(lines, lines[0], " ", NULL);
 768         if (!streq(words[1], "tdb_open"))
 769                 fail(filename, 1, "does not start with tdb_open");
 770
 771         *hashsize = atoi(words[2]);
 772         *tdb_flags = strtoul(words[3], NULL, 0);
 773         *open_flags = strtoul(words[4], NULL, 0);
 774
 775         for (i = 1; lines[i]; i++) {
 776                 const struct op_table *opt;
 777
 778                 words = strsplit(lines, lines[i], " ", NULL);
 779                 if (!words[0] || !words[1])
 780                         fail(filename, i+1, "Expected serial number and op");
 781
 782                 opt = find_keyword(words[1], strlen(words[1]));
 783                 if (!opt) {
 784                         if (streq(words[1], "tdb_close")) {
 785                                 if (lines[i+1])
 786                                         fail(filename, i+2,
 787                                              "lines after tdb_close");
 788                                 *num = i;
 789                                 talloc_free(lines);
 790                                 return maybe_cancel_transaction(filename,
 791                                                                 op, num);
 792                         }
 793                         fail(filename, i+1, "Unknown operation '%s'", words[1]);
 794                 }
 795
 796                 add_op(filename, &op, i, atoi(words[0]), opt->type);
 797                 opt->enhance_op(filename, op, i, words);
 798         }
 799
 800         fprintf(stderr, "%s:%u:last operation is not tdb_close: incomplete?",
 801               filename, i);
 802         talloc_free(lines);
 803         *num = i - 1;
 804         return maybe_cancel_transaction(filename, op, num);
 805 }
 806
 807 /* We remember all the keys we've ever seen, and who has them. */
 808 struct key_user {
 809         unsigned int file;
 810         unsigned int op_num;
 811 };
 812
 813 struct keyinfo {
 814         TDB_DATA key;
 815         unsigned int num_users;
 816         struct key_user *user;
 817 };
 818
 819 static const TDB_DATA must_not_exist;
 820 static const TDB_DATA must_exist;
 821 static const TDB_DATA not_exists_or_empty;
 822
 823 /* NULL means doesn't care if it exists or not, &must_exist means
 824  * it must exist but we don't care what, &must_not_exist means it must
 825  * not exist, otherwise the data it needs. */
 826 static const TDB_DATA *needs(const struct op *op)
 827 {
 828         switch (op->op) {
 829         /* FIXME: Pull forward deps, since we can deadlock */
 830         case OP_TDB_CHAINLOCK:
 831         case OP_TDB_CHAINLOCK_NONBLOCK:
 832         case OP_TDB_CHAINLOCK_MARK:
 833         case OP_TDB_CHAINLOCK_UNMARK:
 834         case OP_TDB_CHAINUNLOCK:
 835         case OP_TDB_CHAINLOCK_READ:
 836         case OP_TDB_CHAINUNLOCK_READ:
 837                 return NULL;
 838
 839         case OP_TDB_APPEND:
 840                 if (op->append.pre.dsize == 0)
 841                         return &not_exists_or_empty;
 842                 return &op->append.pre;
 843
 844         case OP_TDB_STORE:
 845                 if (op->flag == TDB_INSERT) {
 846                         if (op->ret < 0)
 847                                 return &must_exist;
 848                         else
 849                                 return &must_not_exist;
 850                 } else if (op->flag == TDB_MODIFY) {
 851                         if (op->ret < 0)
 852                                 return &must_not_exist;
 853                         else
 854                                 return &must_exist;
 855                 }
 856                 /* No flags?  Don't care */
 857                 return NULL;
 858
 859         case OP_TDB_EXISTS:
 860                 if (op->ret == 1)
 861                         return &must_exist;
 862                 else
 863                         return &must_not_exist;
 864
 865         case OP_TDB_PARSE_RECORD:
 866                 if (op->ret < 0)
 867                         return &must_not_exist;
 868                 return &must_exist;
 869
 870         /* FIXME: handle these. */
 871         case OP_TDB_WIPE_ALL:
 872         case OP_TDB_FIRSTKEY:
 873         case OP_TDB_NEXTKEY:
 874         case OP_TDB_GET_SEQNUM:
 875         case OP_TDB_TRAVERSE:
 876         case OP_TDB_TRANSACTION_COMMIT:
 877         case OP_TDB_TRANSACTION_CANCEL:
 878         case OP_TDB_TRANSACTION_START:
 879                 return NULL;
 880
 881         case OP_TDB_FETCH:
 882                 if (!op->data.dptr)
 883                         return &must_not_exist;
 884                 return &op->data;
 885
 886         case OP_TDB_DELETE:
 887                 if (op->ret < 0)
 888                         return &must_not_exist;
 889                 return &must_exist;
 890
 891         default:
 892                 errx(1, "Unexpected op %i", op->op);
 893         }
 894
 895 }
 896
 897 static bool is_transaction(const struct op *op)
 898 {
 899         return op->op == OP_TDB_TRANSACTION_START;
 900 }
 901
 902 /* What's the data after this op?  pre if nothing changed. */
 903 static const TDB_DATA *gives(const TDB_DATA *key, const TDB_DATA *pre,
 904                              const struct op *op)
 905 {
 906         if (is_transaction(op)) {
 907                 unsigned int i;
 908
 909                 /* Cancelled transactions don't change anything. */
 910                 if (op[op->group_len].op == OP_TDB_TRANSACTION_CANCEL)
 911                         return pre;
 912                 assert(op[op->group_len].op == OP_TDB_TRANSACTION_COMMIT);
 913
 914                 for (i = 1; i < op->group_len; i++) {
 915                         /* This skips nested transactions, too */
 916                         if (op[i].op != OP_TDB_TRAVERSE
 917                             && key_eq(op[i].key, *key))
 918                                 pre = gives(key, pre, &op[i]);
 919                 }
 920                 return pre;
 921         }
 922
 923         /* Failed ops don't change state of db. */
 924         if (op->ret < 0)
 925                 return pre;
 926
 927         if (op->op == OP_TDB_DELETE || op->op == OP_TDB_WIPE_ALL)
 928                 return &tdb_null;
 929
 930         if (op->op == OP_TDB_APPEND)
 931                 return &op->append.post;
 932
 933         if (op->op == OP_TDB_STORE)
 934                 return &op->data;
 935
 936         return pre;
 937 }
 938
 939 static bool in_transaction(const struct op op[], unsigned int i)
 940 {
 941         return op[i].group_start && is_transaction(&op[op[i].group_start]);
 942 }
 943
 944 static bool is_traverse(const struct op *op)
 945 {
 946         return op->op == OP_TDB_TRAVERSE_START
 947                 || op->op == OP_TDB_TRAVERSE_READ_START;
 948 }
 949
 950 static bool in_traverse(const struct op op[], unsigned int i)
 951 {
 952         return op[i].group_start && is_traverse(&op[op[i].group_start]);
 953 }
 954
 955 static struct keyinfo *hash_ops(struct op *op[], unsigned int num_ops[],
 956                                 unsigned int num)
 957 {
 958         unsigned int i, j, h;
 959         struct keyinfo *hash;
 960
 961         hash = talloc_zero_array(op[0], struct keyinfo, total_keys*2);
 962         for (i = 0; i < num; i++) {
 963                 for (j = 1; j < num_ops[i]; j++) {
 964                         /* We can't do this on allocation, due to realloc. */
 965                         list_head_init(&op[i][j].post);
 966                         list_head_init(&op[i][j].pre);
 967
 968                         if (!op[i][j].key.dptr)
 969                                 continue;
 970
 971                         /* We don't wait for traverse keys */
 972                         /* FIXME: We should, for trivial traversals. */
 973                         if (op[i][j].op == OP_TDB_TRAVERSE)
 974                                 continue;
 975
 976                         h = hash_key(&op[i][j].key) % (total_keys * 2);
 977                         while (!key_eq(hash[h].key, op[i][j].key)) {
 978                                 if (!hash[h].key.dptr) {
 979                                         hash[h].key = op[i][j].key;
 980                                         break;
 981                                 }
 982                                 h = (h + 1) % (total_keys * 2);
 983                         }
 984                         /* Might as well save some memory if we can. */
 985                         if (op[i][j].key.dptr != hash[h].key.dptr) {
 986                                 talloc_free(op[i][j].key.dptr);
 987                                 op[i][j].key.dptr = hash[h].key.dptr;
 988                         }
 989                         hash[h].user = talloc_realloc(hash, hash[h].user,
 990                                                      struct key_user,
 991                                                      hash[h].num_users+1);
 992
 993                         /* If it's in a transaction, it's the transaction which
 994                          * matters from an analysis POV. */
 995                         if (in_transaction(op[i], j)) {
 996                                 unsigned start = op[i][j].group_start;
 997
 998                                 /* Don't include twice. */
 999                                 if (hash[h].num_users
1000                                     && hash[h].user[hash[h].num_users-1].file
1001                                         == i
1002                                     && hash[h].user[hash[h].num_users-1].op_num
1003                                         == start)
1004                                         continue;
1005
1006                                 hash[h].user[hash[h].num_users].op_num = start;
1007                         } else
1008                                 hash[h].user[hash[h].num_users].op_num = j;
1009                         hash[h].user[hash[h].num_users].file = i;
1010                         hash[h].num_users++;
1011                 }
1012         }
1013
1014         return hash;
1015 }
1016
1017 static bool satisfies(const TDB_DATA *key, const TDB_DATA *data,
1018                       const struct op *op)
1019 {
1020         const TDB_DATA *need = NULL;
1021
1022         if (is_transaction(op)) {
1023                 unsigned int i;
1024
1025                 /* Look through for an op in this transaction which
1026                  * needs this key. */
1027                 for (i = 1; i < op->group_len; i++) {
1028                         if (op[i].op != OP_TDB_TRAVERSE
1029                             && key_eq(op[i].key, *key)) {
1030                                 need = needs(&op[i]);
1031                                 /* tdb_exists() is special: there might be
1032                                  * something in the transaction with more
1033                                  * specific requirements.  Other ops don't have
1034                                  * specific requirements (eg. store or delete),
1035                                  * but they change the value so we can't get
1036                                  * more information from future ops. */
1037                                 if (op[i].op != OP_TDB_EXISTS)
1038                                         break;
1039                         }
1040                 }
1041         } else
1042                 need = needs(op);
1043
1044         /* Don't need anything?  Cool. */
1045         if (!need)
1046                 return true;
1047
1048         /* This should be tdb_null or a real value. */
1049         assert(data != &must_exist);
1050         assert(data != &must_not_exist);
1051         assert(data != &not_exists_or_empty);
1052
1053         /* Must not exist?  data must not exist. */
1054         if (need == &must_not_exist)
1055                 return data == &tdb_null;
1056
1057         /* Must exist? */
1058         if (need == &must_exist)
1059                 return data != &tdb_null;
1060
1061         /* Either noexist or empty. */
1062         if (need == &not_exists_or_empty)
1063                 return data->dsize == 0;
1064
1065         /* Needs something specific. */
1066         return key_eq(*data, *need);
1067 }
1068
1069 static void move_to_front(struct key_user res[], unsigned off, unsigned elem)
1070 {
1071         if (elem != off) {
1072                 struct key_user tmp = res[elem];
1073                 memmove(res + off + 1, res + off, (elem - off)*sizeof(res[0]));
1074                 res[off] = tmp;
1075         }
1076 }
1077
1078 static void restore_to_pos(struct key_user res[], unsigned off, unsigned elem)
1079 {
1080         if (elem != off) {
1081                 struct key_user tmp = res[off];
1082                 memmove(res + off, res + off + 1, (elem - off)*sizeof(res[0]));
1083                 res[elem] = tmp;
1084         }
1085 }
1086
1087 static bool sort_deps(char *filename[], struct op *op[],
1088                       struct key_user res[],
1089                       unsigned off, unsigned num,
1090                       const TDB_DATA *key, const TDB_DATA *data,
1091                       unsigned num_files, unsigned fuzz)
1092 {
1093         unsigned int i, files_done;
1094         struct op *this_op;
1095         bool done[num_files];
1096
1097         /* None left?  We're sorted. */
1098         if (off == num)
1099                 return true;
1100
1101         /* Does this make serial numbers go backwards?  Allow a little fuzz. */
1102         if (off > 0) {
1103                 int serial1 = op[res[off-1].file][res[off-1].op_num].serial;
1104                 int serial2 = op[res[off].file][res[off].op_num].serial;
1105
1106                 if (serial1 - serial2 > (int)fuzz) {
1107 #if DEBUG_DEPS
1108                         printf("Serial jump too far (%u -> %u)\n",
1109                                serial1, serial2);
1110 #endif
1111                         return false;
1112                 }
1113         }
1114
1115         memset(done, 0, sizeof(done));
1116
1117         /* Since ops within a trace file are ordered, we just need to figure
1118          * out which file to try next.  Since we don't take into account
1119          * inter-key relationships (which exist by virtue of trace file order),
1120          * we minimize the chance of harm by trying to keep in serial order. */
1121         for (files_done = 0, i = off; i < num && files_done < num_files; i++) {
1122                 if (done[res[i].file])
1123                         continue;
1124
1125                 this_op = &op[res[i].file][res[i].op_num];
1126
1127                 /* Is what we have good enough for this op? */
1128                 if (satisfies(key, data, this_op)) {
1129                         move_to_front(res, off, i);
1130                         if (sort_deps(filename, op, res, off+1, num,
1131                                       key, gives(key, data, this_op),
1132                                       num_files, fuzz))
1133                                 return true;
1134                         restore_to_pos(res, off, i);
1135                 }
1136                 done[res[i].file] = true;
1137                 files_done++;
1138         }
1139
1140         /* No combination worked. */
1141         return false;
1142 }
1143
1144 static void check_dep_sorting(struct key_user user[], unsigned num_users,
1145                               unsigned num_files)
1146 {
1147 #if DEBUG_DEPS
1148         unsigned int i;
1149         unsigned minima[num_files];
1150
1151         memset(minima, 0, sizeof(minima));
1152         for (i = 0; i < num_users; i++) {
1153                 assert(minima[user[i].file] < user[i].op_num);
1154                 minima[user[i].file] = user[i].op_num;
1155         }
1156 #endif
1157 }
1158
1159 /* All these ops happen on the same key.  Which comes first?
1160  *
1161  * This can happen both because read ops or failed write ops don't
1162  * change serial number, and also due to race since we access the
1163  * number unlocked (the race can cause less detectable ordering problems,
1164  * in which case we'll deadlock and report: fix manually in that case).
1165  */
1166 static void figure_deps(char *filename[], struct op *op[],
1167                         const TDB_DATA *key, struct key_user user[],
1168                         unsigned num_users, unsigned num_files)
1169 {
1170         /* We assume database starts empty. */
1171         const struct TDB_DATA *data = &tdb_null;
1172         unsigned int fuzz;
1173
1174         /* We prefer to keep strict serial order if possible: it's the
1175          * most likely.  We get more lax if that fails. */
1176         for (fuzz = 0; fuzz < 100; fuzz = (fuzz + 1)*2) {
1177                 if (sort_deps(filename, op, user, 0, num_users, key, data,
1178                               num_files, fuzz))
1179                         break;
1180         }
1181
1182         if (fuzz >= 100)
1183                 fail(filename[user[0].file], user[0].op_num+1,
1184                      "Could not resolve inter-dependencies");
1185
1186         check_dep_sorting(user, num_users, num_files);
1187 }
1188
1189 static void sort_ops(struct keyinfo hash[], char *filename[], struct op *op[],
1190                      unsigned int num)
1191 {
1192         unsigned int h;
1193
1194         /* Gcc nexted function extension.  How cool is this? */
1195         int compare_serial(const void *_a, const void *_b)
1196         {
1197                 const struct key_user *a = _a, *b = _b;
1198
1199                 /* First, maintain order within any trace file. */
1200                 if (a->file == b->file)
1201                         return a->op_num - b->op_num;
1202
1203                 /* Otherwise, arrange by serial order. */
1204                 return op[a->file][a->op_num].serial
1205                         - op[b->file][b->op_num].serial;
1206         }
1207
1208         /* Now sort into serial order. */
1209         for (h = 0; h < total_keys * 2; h++) {
1210                 struct key_user *user = hash[h].user;
1211
1212                 qsort(user, hash[h].num_users, sizeof(user[0]), compare_serial);
1213                 figure_deps(filename, op, &hash[h].key, user, hash[h].num_users,
1214                             num);
1215         }
1216 }
1217
1218 static int destroy_depend(struct depend *dep)
1219 {
1220         list_del(&dep->pre_list);
1221         list_del(&dep->post_list);
1222         return 0;
1223 }
1224
1225 static void add_dependency(void *ctx,
1226                            struct op *op[],
1227                            char *filename[],
1228                            unsigned int needs_file,
1229                            unsigned int needs_opnum,
1230                            unsigned int satisfies_file,
1231                            unsigned int satisfies_opnum)
1232 {
1233         struct depend *dep;
1234
1235         /* We don't depend on ourselves. */
1236         if (needs_file == satisfies_file) {
1237                 assert(satisfies_opnum < needs_opnum);
1238                 return;
1239         }
1240
1241 #if DEBUG_DEPS
1242         printf("%s:%u: depends on %s:%u\n",
1243                filename[needs_file], needs_opnum+1,
1244                filename[satisfies_file], satisfies_opnum+1);
1245 #endif
1246
1247 #if TRAVERSALS_TAKE_TRANSACTION_LOCK
1248         /* If something in a traverse depends on something in another
1249          * traverse/transaction, it creates a dependency between the
1250          * two groups. */
1251         if ((in_traverse(op[satisfies_file], satisfies_opnum)
1252              && op[needs_file][needs_opnum].group_start)
1253             || (in_traverse(op[needs_file], needs_opnum)
1254                 && op[satisfies_file][satisfies_opnum].group_start)) {
1255                 unsigned int sat;
1256
1257                 /* We are satisfied by end of group. */
1258                 sat = op[satisfies_file][satisfies_opnum].group_start;
1259                 satisfies_opnum = sat + op[satisfies_file][sat].group_len;
1260                 /* And we need that done by start of our group. */
1261                 needs_opnum = op[needs_file][needs_opnum].group_start;
1262         }
1263
1264         /* There is also this case:
1265          *  <traverse> <read foo> ...
1266          *  <transaction> ... </transaction> <create foo>
1267          * Where if we start the traverse then wait, we could block
1268          * the transaction and deadlock.
1269          *
1270          * We try to address this by ensuring that where seqnum indicates it's
1271          * possible, we wait for <create foo> before *starting* traverse.
1272          */
1273         else if (in_traverse(op[needs_file], needs_opnum)) {
1274                 struct op *need = &op[needs_file][needs_opnum];
1275                 if (op[needs_file][need->group_start].serial >
1276                     op[satisfies_file][satisfies_opnum].serial) {
1277                         needs_opnum = need->group_start;
1278                 }
1279         }
1280 #endif
1281
1282         /* If you depend on a transaction, you actually depend on it ending. */
1283         if (is_transaction(&op[satisfies_file][satisfies_opnum])) {
1284                 satisfies_opnum
1285                         += op[satisfies_file][satisfies_opnum].group_len;
1286 #if DEBUG_DEPS
1287                 printf("-> Actually end of transaction %s:%u\n",
1288                        filename[satisfies_file], satisfies_opnum+1);
1289 #endif
1290         } else
1291                 /* We should never create a dependency from middle of
1292                  * a transaction. */
1293                 assert(!in_transaction(op[satisfies_file], satisfies_opnum)
1294                        || op[satisfies_file][satisfies_opnum].op
1295                        == OP_TDB_TRANSACTION_COMMIT
1296                        || op[satisfies_file][satisfies_opnum].op
1297                        == OP_TDB_TRANSACTION_CANCEL);
1298
1299         assert(op[needs_file][needs_opnum].op != OP_TDB_TRAVERSE);
1300         assert(op[satisfies_file][satisfies_opnum].op != OP_TDB_TRAVERSE);
1301
1302         dep = talloc(ctx, struct depend);
1303         dep->needs_file = needs_file;
1304         dep->needs_opnum = needs_opnum;
1305         dep->satisfies_file = satisfies_file;
1306         dep->satisfies_opnum = satisfies_opnum;
1307         list_add(&op[satisfies_file][satisfies_opnum].post, &dep->post_list);
1308         list_add(&op[needs_file][needs_opnum].pre, &dep->pre_list);
1309         talloc_set_destructor(dep, destroy_depend);
1310 }
1311
1312 static bool changes_db(const TDB_DATA *key, const struct op *op)
1313 {
1314         return gives(key, NULL, op) != NULL;
1315 }
1316
1317 static void depend_on_previous(struct op *op[],
1318                                char *filename[],
1319                                unsigned int num,
1320                                struct key_user user[],
1321                                unsigned int i,
1322                                int prev)
1323 {
1324         bool deps[num];
1325         int j;
1326
1327         if (i == 0)
1328                 return;
1329
1330         if (prev == i - 1) {
1331                 /* Just depend on previous. */
1332                 add_dependency(NULL, op, filename,
1333                                user[i].file, user[i].op_num,
1334                                user[prev].file, user[prev].op_num);
1335                 return;
1336         }
1337
1338         /* We have to wait for the readers.  Find last one in *each* file. */
1339         memset(deps, 0, sizeof(deps));
1340         deps[user[i].file] = true;
1341         for (j = i - 1; j > prev; j--) {
1342                 if (!deps[user[j].file]) {
1343                         add_dependency(NULL, op, filename,
1344                                        user[i].file, user[i].op_num,
1345                                        user[j].file, user[j].op_num);
1346                         deps[user[j].file] = true;
1347                 }
1348         }
1349 }
1350
1351 /* This is simple, but not complete.  We don't take into account
1352  * indirect dependencies. */
1353 static void optimize_dependencies(struct op *op[], unsigned int num_ops[],
1354                                   unsigned int num)
1355 {
1356         unsigned int i, j;
1357
1358         /* There can only be one real dependency on each file */
1359         for (i = 0; i < num; i++) {
1360                 for (j = 1; j < num_ops[i]; j++) {
1361                         struct depend *dep, *next;
1362                         struct depend *prev[num];
1363
1364                         memset(prev, 0, sizeof(prev));
1365
1366                         list_for_each_safe(&op[i][j].pre, dep, next, pre_list) {
1367                                 if (!prev[dep->satisfies_file]) {
1368                                         prev[dep->satisfies_file] = dep;
1369                                         continue;
1370                                 }
1371                                 if (prev[dep->satisfies_file]->satisfies_opnum
1372                                     < dep->satisfies_opnum) {
1373                                         talloc_free(prev[dep->satisfies_file]);
1374                                         prev[dep->satisfies_file] = dep;
1375                                 } else
1376                                         talloc_free(dep);
1377                         }
1378                 }
1379         }
1380
1381         for (i = 0; i < num; i++) {
1382                 int deps[num];
1383
1384                 for (j = 0; j < num; j++)
1385                         deps[j] = -1;
1386
1387                 for (j = 1; j < num_ops[i]; j++) {
1388                         struct depend *dep, *next;
1389
1390                         list_for_each_safe(&op[i][j].pre, dep, next, pre_list) {
1391                                 if (deps[dep->satisfies_file]
1392                                     >= (int)dep->satisfies_opnum)
1393                                         talloc_free(dep);
1394                                 else
1395                                         deps[dep->satisfies_file]
1396                                                 = dep->satisfies_opnum;
1397                         }
1398                 }
1399         }
1400 }
1401
1402 #if TRAVERSALS_TAKE_TRANSACTION_LOCK
1403 struct traverse_dep {
1404         unsigned int file;
1405         unsigned int op_num;
1406 };
1407
1408 /* Force an order among the traversals, so they don't deadlock (as much) */
1409 static void make_traverse_depends(char *filename[],
1410                                   struct op *op[], unsigned int num_ops[],
1411                                   unsigned int num)
1412 {
1413         unsigned int i, num_traversals = 0;
1414         int j;
1415         struct traverse_dep *dep;
1416
1417         /* Sort by which one runs first. */
1418         int compare_traverse_dep(const void *_a, const void *_b)
1419         {
1420                 const struct traverse_dep *ta = _a, *tb = _b;
1421                 const struct op *a = &op[ta->file][ta->op_num],
1422                         *b = &op[tb->file][tb->op_num];
1423
1424                 if (a->serial != b->serial)
1425                         return a->serial - b->serial;
1426
1427                 /* If they have same serial, it means one didn't make any
1428                  * changes.  Thus sort by end in that case. */
1429                 return a[a->group_len].serial - b[b->group_len].serial;
1430         }
1431
1432         dep = talloc_array(NULL, struct traverse_dep, 1);
1433
1434         /* Count them. */
1435         for (i = 0; i < num; i++) {
1436                 for (j = 1; j < num_ops[i]; j++) {
1437                         /* Traverse start (ignore those in
1438                          * transactions; they're already covered by
1439                          * transaction dependencies). */
1440                         if (is_traverse(&op[i][j])
1441                             && !in_transaction(op[i], j)) {
1442                                 dep = talloc_realloc(NULL, dep,
1443                                                      struct traverse_dep,
1444                                                      num_traversals+1);
1445                                 dep[num_traversals].file = i;
1446                                 dep[num_traversals].op_num = j;
1447                                 num_traversals++;
1448                         }
1449                 }
1450         }
1451         qsort(dep, num_traversals, sizeof(dep[0]), compare_traverse_dep);
1452
1453         for (i = 1; i < num_traversals; i++) {
1454                 const struct op *prev = &op[dep[i-1].file][dep[i-1].op_num];
1455
1456                 /* Only make dependency if it's clear. */
1457                 if (compare_traverse_dep(&dep[i], &dep[i-1])) {
1458                         /* i depends on end of traverse i-1. */
1459                         add_dependency(NULL, op, filename,
1460                                        dep[i].file, dep[i].op_num,
1461                                        dep[i-1].file, dep[i-1].op_num
1462                                        + prev->group_len);
1463                 }
1464         }
1465         talloc_free(dep);
1466 }
1467 #endif
1468
1469 static void derive_dependencies(char *filename[],
1470                                 struct op *op[], unsigned int num_ops[],
1471                                 unsigned int num)
1472 {
1473         struct keyinfo *hash;
1474         unsigned int h, i;
1475
1476         /* Create hash table for faster key lookup. */
1477         hash = hash_ops(op, num_ops, num);
1478
1479         /* Sort them by serial number. */
1480         sort_ops(hash, filename, op, num);
1481
1482         /* Create dependencies back to the last change, rather than
1483          * creating false dependencies by naively making each one
1484          * depend on the previous.  This has two purposes: it makes
1485          * later optimization simpler, and it also avoids deadlock with
1486          * same sequence number ops inside traversals (if one
1487          * traversal doesn't write anything, two ops can have the same
1488          * sequence number yet we can create a traversal dependency
1489          * the other way). */
1490         for (h = 0; h < total_keys * 2; h++) {
1491                 int prev = -1;
1492
1493                 if (hash[h].num_users < 2)
1494                         continue;
1495
1496                 for (i = 0; i < hash[h].num_users; i++) {
1497                         if (changes_db(&hash[h].key, &op[hash[h].user[i].file]
1498                                        [hash[h].user[i].op_num])) {
1499                                 depend_on_previous(op, filename, num,
1500                                                    hash[h].user, i, prev);
1501                                 prev = i;
1502                         } else if (prev >= 0)
1503                                 add_dependency(hash, op, filename,
1504                                                hash[h].user[i].file,
1505                                                hash[h].user[i].op_num,
1506                                                hash[h].user[prev].file,
1507                                                hash[h].user[prev].op_num);
1508                 }
1509         }
1510
1511 #if TRAVERSALS_TAKE_TRANSACTION_LOCK
1512         make_traverse_depends(filename, op, num_ops, num);
1513 #endif
1514
1515         optimize_dependencies(op, num_ops, num);
1516 }
1517
1518 int main(int argc, char *argv[])
1519 {
1520         struct timeval start, end;
1521         unsigned int i, num_ops[argc], hashsize[argc], tdb_flags[argc], open_flags[argc];
1522         struct op *op[argc];
1523         int fds[2];
1524         char c;
1525         bool ok = true;
1526
1527         if (argc < 3)
1528                 errx(1, "Usage: %s <tdbfile> <tracefile>...", argv[0]);
1529
1530         pipes = talloc_array(NULL, struct pipe, argc - 2);
1531         for (i = 0; i < argc - 2; i++) {
1532                 printf("Loading tracefile %s...", argv[2+i]);
1533                 fflush(stdout);
1534                 op[i] = load_tracefile(argv[2+i], &num_ops[i], &hashsize[i],
1535                                        &tdb_flags[i], &open_flags[i]);
1536                 if (pipe(pipes[i].fd) != 0)
1537                         err(1, "creating pipe");
1538                 printf("done\n");
1539         }
1540
1541         printf("Calculating inter-dependencies...");
1542         fflush(stdout);
1543         derive_dependencies(argv+2, op, num_ops, i);
1544         printf("done\n");
1545
1546         /* Don't fork for single arg case: simple debugging. */
1547         if (argc == 3) {
1548                 struct tdb_context *tdb;
1549                 tdb = tdb_open_ex(argv[1], hashsize[0], tdb_flags[0]|TDB_NOSYNC,
1550                                   open_flags[0], 0600, NULL, hash_key);
1551                 printf("Single threaded run...");
1552                 fflush(stdout);
1553
1554                 run_ops(tdb, pipes[0].fd[0], argv+2, op, 0, 1, num_ops[0],
1555                         false);
1556                 check_deps(argv[2], op[0], num_ops[0]);
1557
1558                 printf("done\n");
1559                 exit(0);
1560         }
1561
1562         if (pipe(fds) != 0)
1563                 err(1, "creating pipe");
1564
1565         for (i = 0; i < argc - 2; i++) {
1566                 struct tdb_context *tdb;
1567
1568                 switch (fork()) {
1569                 case -1:
1570                         err(1, "fork failed");
1571                 case 0:
1572                         close(fds[1]);
1573                         tdb = tdb_open_ex(argv[1], hashsize[i],
1574                                           tdb_flags[i]|TDB_NOSYNC,
1575                                           open_flags[i], 0600, NULL, hash_key);
1576                         if (!tdb)
1577                                 err(1, "Opening tdb %s", argv[1]);
1578
1579                         /* This catches parent exiting. */
1580                         if (read(fds[0], &c, 1) != 1)
1581                                 exit(1);
1582                         run_ops(tdb, pipes[i].fd[0], argv+2, op, i, 1,
1583                                 num_ops[i], false);
1584                         check_deps(argv[2+i], op[i], num_ops[i]);
1585                         exit(0);
1586                 default:
1587                         break;
1588                 }
1589         }
1590
1591         /* Let everything settle. */
1592         sleep(1);
1593
1594         printf("Starting run...");
1595         fflush(stdout);
1596         gettimeofday(&start, NULL);
1597         /* Tell them all to go!  Any write of sufficient length will do. */
1598         if (write(fds[1], hashsize, i) != i)
1599                 err(1, "Writing to wakeup pipe");
1600
1601         for (i = 0; i < argc - 2; i++) {
1602                 int status;
1603                 wait(&status);
1604                 if (!WIFEXITED(status)) {
1605                         warnx("Child died with signal %i", WTERMSIG(status));
1606                         ok = false;
1607                 } else if (WEXITSTATUS(status) != 0)
1608                         /* Assume child spat out error. */
1609                         ok = false;
1610         }
1611         if (!ok)
1612                 exit(1);
1613
1614         gettimeofday(&end, NULL);
1615         printf("done\n");
1616
1617         end.tv_sec -= start.tv_sec;
1618         printf("Time replaying: %lu usec\n",
1619                end.tv_sec * 1000000UL + (end.tv_usec - start.tv_usec));
1620
1621         exit(0);
1622 }