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 #include <fcntl.h>
  19
  20 #define STRINGIFY2(x) #x
  21 #define STRINGIFY(x) STRINGIFY2(x)
  22
  23 static bool quiet = false;
  24
  25 /* Avoid mod by zero */
  26 static unsigned int total_keys = 1;
  27
  28 /* All the wipe_all ops. */
  29 static struct op_desc *wipe_alls = NULL;
  30 static unsigned int num_wipe_alls = 0;
  31
  32 /* #define DEBUG_DEPS 1 */
  33
  34 /* Traversals block transactions in the current implementation. */
  35 #define TRAVERSALS_TAKE_TRANSACTION_LOCK 1
  36
  37 struct pipe {
  38         int fd[2];
  39 };
  40 static struct pipe *pipes;
  41 static int backoff_fd = -1;
  42
  43 static void __attribute__((noreturn)) fail(const char *filename,
  44                                            unsigned int line,
  45                                            const char *fmt, ...)
  46 {
  47         va_list ap;
  48
  49         va_start(ap, fmt);
  50         fprintf(stderr, "%s:%u: FAIL: ", filename, line);
  51         vfprintf(stderr, fmt, ap);
  52         fprintf(stderr, "\n");
  53         va_end(ap);
  54         exit(1);
  55 }
  56
  57 /* Try or die. */
  58 #define try(expr, expect)                                               \
  59         do {                                                            \
  60                 int ret = (expr);                                       \
  61                 if (ret != (expect))                                    \
  62                         fail(filename[file], i+1,                       \
  63                              STRINGIFY(expr) "= %i", ret);              \
  64         } while (0)
  65
  66 /* Try or imitate results. */
  67 #define unreliable(expr, expect, force, undo)                           \
  68         do {                                                            \
  69                 int ret = expr;                                         \
  70                 if (ret != expect) {                                    \
  71                         fprintf(stderr, "%s:%u: %s gave %i not %i",     \
  72                                 filename[file], i+1, STRINGIFY(expr),   \
  73                                 ret, expect);                           \
  74                         if (expect == 0)                                \
  75                                 force;                                  \
  76                         else                                            \
  77                                 undo;                                   \
  78                 }                                                       \
  79         } while (0)
  80
  81 static bool key_eq(TDB_DATA a, TDB_DATA b)
  82 {
  83         if (a.dsize != b.dsize)
  84                 return false;
  85         return memcmp(a.dptr, b.dptr, a.dsize) == 0;
  86 }
  87
  88 /* This is based on the hash algorithm from gdbm */
  89 static unsigned int hash_key(TDB_DATA *key)
  90 {
  91         uint32_t value; /* Used to compute the hash value.  */
  92         uint32_t   i;   /* Used to cycle through random values. */
  93
  94         /* Set the initial value from the key size. */
  95         for (value = 0x238F13AF ^ key->dsize, i=0; i < key->dsize; i++)
  96                 value = (value + (key->dptr[i] << (i*5 % 24)));
  97
  98         return (1103515243 * value + 12345);
  99 }
 100
 101 enum op_type {
 102         OP_TDB_LOCKALL,
 103         OP_TDB_LOCKALL_MARK,
 104         OP_TDB_LOCKALL_UNMARK,
 105         OP_TDB_LOCKALL_NONBLOCK,
 106         OP_TDB_UNLOCKALL,
 107         OP_TDB_LOCKALL_READ,
 108         OP_TDB_LOCKALL_READ_NONBLOCK,
 109         OP_TDB_UNLOCKALL_READ,
 110         OP_TDB_CHAINLOCK,
 111         OP_TDB_CHAINLOCK_NONBLOCK,
 112         OP_TDB_CHAINLOCK_MARK,
 113         OP_TDB_CHAINLOCK_UNMARK,
 114         OP_TDB_CHAINUNLOCK,
 115         OP_TDB_CHAINLOCK_READ,
 116         OP_TDB_CHAINUNLOCK_READ,
 117         OP_TDB_PARSE_RECORD,
 118         OP_TDB_EXISTS,
 119         OP_TDB_STORE,
 120         OP_TDB_APPEND,
 121         OP_TDB_GET_SEQNUM,
 122         OP_TDB_WIPE_ALL,
 123         OP_TDB_TRANSACTION_START,
 124         OP_TDB_TRANSACTION_CANCEL,
 125         OP_TDB_TRANSACTION_PREPARE_COMMIT,
 126         OP_TDB_TRANSACTION_COMMIT,
 127         OP_TDB_TRAVERSE_READ_START,
 128         OP_TDB_TRAVERSE_START,
 129         OP_TDB_TRAVERSE_END,
 130         OP_TDB_TRAVERSE,
 131         OP_TDB_TRAVERSE_END_EARLY,
 132         OP_TDB_FIRSTKEY,
 133         OP_TDB_NEXTKEY,
 134         OP_TDB_FETCH,
 135         OP_TDB_DELETE,
 136         OP_TDB_REPACK,
 137 };
 138
 139 struct op {
 140         unsigned int seqnum;
 141         enum op_type type;
 142         TDB_DATA key;
 143         TDB_DATA data;
 144         int ret;
 145
 146         /* Who is waiting for us? */
 147         struct list_head post;
 148         /* What are we waiting for? */
 149         struct list_head pre;
 150
 151         /* If I'm part of a group (traverse/transaction) where is
 152          * start?  (Otherwise, 0) */
 153         unsigned int group_start;
 154
 155         union {
 156                 int flag; /* open and store */
 157                 struct {  /* append */
 158                         TDB_DATA pre;
 159                         TDB_DATA post;
 160                 } append;
 161                 /* transaction/traverse start/chainlock */
 162                 unsigned int group_len;
 163         };
 164 };
 165
 166 struct op_desc {
 167         unsigned int file;
 168         unsigned int op_num;
 169 };
 170
 171 static unsigned char hex_char(const char *filename, unsigned int line, char c)
 172 {
 173         c = toupper(c);
 174         if (c >= 'A' && c <= 'F')
 175                 return c - 'A' + 10;
 176         if (c >= '0' && c <= '9')
 177                 return c - '0';
 178         fail(filename, line, "invalid hex character '%c'", c);
 179 }
 180
 181 /* TDB data is <size>:<%02x>* */
 182 static TDB_DATA make_tdb_data(const void *ctx,
 183                               const char *filename, unsigned int line,
 184                               const char *word)
 185 {
 186         TDB_DATA data;
 187         unsigned int i;
 188         const char *p;
 189
 190         if (streq(word, "NULL"))
 191                 return tdb_null;
 192
 193         data.dsize = atoi(word);
 194         data.dptr = talloc_array(ctx, unsigned char, data.dsize);
 195         p = strchr(word, ':');
 196         if (!p)
 197                 fail(filename, line, "invalid tdb data '%s'", word);
 198         p++;
 199         for (i = 0; i < data.dsize; i++)
 200                 data.dptr[i] = hex_char(filename, line, p[i*2])*16
 201                         + hex_char(filename, line, p[i*2+1]);
 202
 203         return data;
 204 }
 205
 206 static void add_op(const char *filename, struct op **op, unsigned int i,
 207                    unsigned int seqnum, enum op_type type)
 208 {
 209         struct op *new;
 210         *op = talloc_realloc(NULL, *op, struct op, i+1);
 211         new = (*op) + i;
 212         new->type = type;
 213         new->seqnum = seqnum;
 214         new->ret = 0;
 215         new->group_start = 0;
 216 }
 217
 218 static void op_add_nothing(char *filename[], struct op op[],
 219                            unsigned file, unsigned op_num, char *words[])
 220 {
 221         if (words[2])
 222                 fail(filename[file], op_num+1, "Expected no arguments");
 223         op[op_num].key = tdb_null;
 224 }
 225
 226 static void op_add_key(char *filename[], struct op op[],
 227                        unsigned file, unsigned op_num, char *words[])
 228 {
 229         if (words[2] == NULL || words[3])
 230                 fail(filename[file], op_num+1, "Expected just a key");
 231
 232         op[op_num].key = make_tdb_data(op, filename[file], op_num+1, words[2]);
 233         total_keys++;
 234 }
 235
 236 static void op_add_key_ret(char *filename[], struct op op[],
 237                            unsigned file, unsigned op_num, char *words[])
 238 {
 239         if (!words[2] || !words[3] || !words[4] || words[5]
 240             || !streq(words[3], "="))
 241                 fail(filename[file], op_num+1, "Expected <key> = <ret>");
 242         op[op_num].ret = atoi(words[4]);
 243         op[op_num].key = make_tdb_data(op, filename[file], op_num+1, words[2]);
 244         /* May only be a unique key if it fails */
 245         if (op[op_num].ret != 0)
 246                 total_keys++;
 247 }
 248
 249 static void op_add_key_data(char *filename[], struct op op[],
 250                             unsigned file, unsigned op_num, char *words[])
 251 {
 252         if (!words[2] || !words[3] || !words[4] || words[5]
 253             || !streq(words[3], "="))
 254                 fail(filename[file], op_num+1, "Expected <key> = <data>");
 255         op[op_num].key = make_tdb_data(op, filename[file], op_num+1, words[2]);
 256         op[op_num].data = make_tdb_data(op, filename[file], op_num+1, words[4]);
 257         /* Likely only be a unique key if it fails */
 258         if (!op[op_num].data.dptr)
 259                 total_keys++;
 260         else if (random() % 2)
 261                 total_keys++;
 262 }
 263
 264 /* We don't record the keys or data for a traverse, as we don't use them. */
 265 static void op_add_traverse(char *filename[], struct op op[],
 266                             unsigned file, unsigned op_num, char *words[])
 267 {
 268         if (!words[2] || !words[3] || !words[4] || words[5]
 269             || !streq(words[3], "="))
 270                 fail(filename[file], op_num+1, "Expected <key> = <data>");
 271         op[op_num].key = tdb_null;
 272 }
 273
 274 /* Full traverse info is useful for debugging, but changing it to
 275  * "traversefn" without the data makes the traces *much* smaller! */
 276 static void op_add_traversefn(char *filename[], struct op op[],
 277                             unsigned file, unsigned op_num, char *words[])
 278 {
 279         if (words[2])
 280                 fail(filename[file], op_num+1, "Expected no values");
 281         op[op_num].key = tdb_null;
 282 }
 283
 284 /* <seqnum> tdb_store <rec> <rec> <flag> = <ret> */
 285 static void op_add_store(char *filename[], struct op op[],
 286                          unsigned file, unsigned op_num, char *words[])
 287 {
 288         if (!words[2] || !words[3] || !words[4] || !words[5] || !words[6]
 289             || words[7] || !streq(words[5], "="))
 290                 fail(filename[file], op_num+1, "Expect <key> <data> <flag> = <ret>");
 291
 292         op[op_num].flag = strtoul(words[4], NULL, 0);
 293         op[op_num].ret = atoi(words[6]);
 294         op[op_num].key = make_tdb_data(op, filename[file], op_num+1, words[2]);
 295         op[op_num].data = make_tdb_data(op, filename[file], op_num+1, words[3]);
 296         total_keys++;
 297 }
 298
 299 /* <seqnum> tdb_append <rec> <rec> = <rec> */
 300 static void op_add_append(char *filename[], struct op op[],
 301                           unsigned file, unsigned op_num, char *words[])
 302 {
 303         if (!words[2] || !words[3] || !words[4] || !words[5] || words[6]
 304             || !streq(words[4], "="))
 305                 fail(filename[file], op_num+1, "Expect <key> <data> = <rec>");
 306
 307         op[op_num].key = make_tdb_data(op, filename[file], op_num+1, words[2]);
 308         op[op_num].data = make_tdb_data(op, filename[file], op_num+1, words[3]);
 309
 310         op[op_num].append.post
 311                 = make_tdb_data(op, filename[file], op_num+1, words[5]);
 312
 313         /* By subtraction, figure out what previous data was. */
 314         op[op_num].append.pre.dptr = op[op_num].append.post.dptr;
 315         op[op_num].append.pre.dsize
 316                 = op[op_num].append.post.dsize - op[op_num].data.dsize;
 317         total_keys++;
 318 }
 319
 320 /* <seqnum> tdb_get_seqnum = <ret> */
 321 static void op_add_seqnum(char *filename[], struct op op[],
 322                           unsigned file, unsigned op_num, char *words[])
 323 {
 324         if (!words[2] || !words[3] || words[4] || !streq(words[2], "="))
 325                 fail(filename[file], op_num+1, "Expect = <ret>");
 326
 327         op[op_num].key = tdb_null;
 328         op[op_num].ret = atoi(words[3]);
 329 }
 330
 331 static void op_add_traverse_start(char *filename[], struct op op[],
 332                                   unsigned file, unsigned op_num, char *words[])
 333 {
 334         if (words[2])
 335                 fail(filename[file], op_num+1, "Expect no arguments");
 336
 337         op[op_num].key = tdb_null;
 338         op[op_num].group_len = 0;
 339 }
 340
 341 static void op_add_transaction(char *filename[], struct op op[],
 342                                unsigned file, unsigned op_num, char *words[])
 343 {
 344         if (words[2])
 345                 fail(filename[file], op_num+1, "Expect no arguments");
 346
 347         op[op_num].key = tdb_null;
 348         op[op_num].group_len = 0;
 349 }
 350
 351 static void op_add_chainlock(char *filename[], struct op op[],
 352                              unsigned file, unsigned op_num, char *words[])
 353 {
 354         if (words[2] == NULL || words[3])
 355                 fail(filename[file], op_num+1, "Expected just a key");
 356
 357         /* A chainlock key isn't a key in the normal sense; it doesn't
 358          * have to be in the db at all.  Also, we don't want to hash this op. */
 359         op[op_num].data = make_tdb_data(op, filename[file], op_num+1, words[2]);
 360         op[op_num].key = tdb_null;
 361         op[op_num].group_len = 0;
 362 }
 363
 364 static void op_add_chainlock_ret(char *filename[], struct op op[],
 365                                  unsigned file, unsigned op_num, char *words[])
 366 {
 367         if (!words[2] || !words[3] || !words[4] || words[5]
 368             || !streq(words[3], "="))
 369                 fail(filename[file], op_num+1, "Expected <key> = <ret>");
 370         op[op_num].ret = atoi(words[4]);
 371         op[op_num].data = make_tdb_data(op, filename[file], op_num+1, words[2]);
 372         op[op_num].key = tdb_null;
 373         op[op_num].group_len = 0;
 374         total_keys++;
 375 }
 376
 377 static void op_add_wipe_all(char *filename[], struct op op[],
 378                             unsigned file, unsigned op_num, char *words[])
 379 {
 380         if (words[2])
 381                 fail(filename[file], op_num+1, "Expected no arguments");
 382         op[op_num].key = tdb_null;
 383         wipe_alls = talloc_realloc(NULL, wipe_alls, struct op_desc,
 384                                    num_wipe_alls+1);
 385         wipe_alls[num_wipe_alls].file = file;
 386         wipe_alls[num_wipe_alls].op_num = op_num;
 387         num_wipe_alls++;
 388 }
 389
 390 static int op_find_start(struct op op[], unsigned int op_num, enum op_type type)
 391 {
 392         unsigned int i;
 393
 394         for (i = op_num-1; i > 0; i--) {
 395                 if (op[i].type == type && !op[i].group_len)
 396                         return i;
 397         }
 398         return 0;
 399 }
 400
 401 static void op_analyze_transaction(char *filename[], struct op op[],
 402                                    unsigned file, unsigned op_num,
 403                                    char *words[])
 404 {
 405         unsigned int start, i;
 406
 407         op[op_num].key = tdb_null;
 408
 409         if (words[2])
 410                 fail(filename[file], op_num+1, "Expect no arguments");
 411
 412         start = op_find_start(op, op_num, OP_TDB_TRANSACTION_START);
 413         if (!start)
 414                 fail(filename[file], op_num+1, "no transaction start found");
 415
 416         op[start].group_len = op_num - start;
 417
 418         /* This rolls in nested transactions.  I think that's right. */
 419         for (i = start; i <= op_num; i++)
 420                 op[i].group_start = start;
 421 }
 422
 423 /* We treat chainlocks a lot like transactions, even though that's overkill */
 424 static void op_analyze_chainlock(char *filename[], struct op op[],
 425                                  unsigned file, unsigned op_num, char *words[])
 426 {
 427         unsigned int i, start;
 428
 429         if (words[2] == NULL || words[3])
 430                 fail(filename[file], op_num+1, "Expected just a key");
 431
 432         op[op_num].data = make_tdb_data(op, filename[file], op_num+1, words[2]);
 433         op[op_num].key = tdb_null;
 434         total_keys++;
 435
 436         start = op_find_start(op, op_num, OP_TDB_CHAINLOCK);
 437         if (!start)
 438                 start = op_find_start(op, op_num, OP_TDB_CHAINLOCK_READ);
 439         if (!start)
 440                 fail(filename[file], op_num+1, "no initial chainlock found");
 441
 442         /* FIXME: We'd have to do something clever to make this work
 443          * vs. deadlock. */
 444         if (!key_eq(op[start].data, op[op_num].data))
 445                 fail(filename[file], op_num+1, "nested chainlock calls?");
 446
 447         op[start].group_len = op_num - start;
 448         for (i = start; i <= op_num; i++)
 449                 op[i].group_start = start;
 450 }
 451
 452 static void op_analyze_traverse(char *filename[], struct op op[],
 453                                 unsigned file, unsigned op_num, char *words[])
 454 {
 455         int i, start;
 456
 457         op[op_num].key = tdb_null;
 458
 459         /* = %u means traverse function terminated. */
 460         if (words[2]) {
 461                 if (!streq(words[2], "=") || !words[3] || words[4])
 462                         fail(filename[file], op_num+1, "expect = <num>");
 463                 op[op_num].ret = atoi(words[3]);
 464         } else
 465                 op[op_num].ret = 0;
 466
 467         start = op_find_start(op, op_num, OP_TDB_TRAVERSE_START);
 468         if (!start)
 469                 start = op_find_start(op, op_num, OP_TDB_TRAVERSE_READ_START);
 470         if (!start)
 471                 fail(filename[file], op_num+1, "no traversal start found");
 472
 473         op[start].group_len = op_num - start;
 474
 475         /* Don't roll in nested traverse/chainlock */
 476         for (i = start; i <= op_num; i++)
 477                 if (!op[i].group_start)
 478                         op[i].group_start = start;
 479 }
 480
 481 /* Keep -Wmissing-declarations happy: */
 482 const struct op_table *
 483 find_keyword (register const char *str, register unsigned int len);
 484
 485 #include "keywords.c"
 486
 487 struct depend {
 488         /* We can have more than one */
 489         struct list_node pre_list;
 490         struct list_node post_list;
 491         struct op_desc needs;
 492         struct op_desc prereq;
 493 };
 494
 495 static void check_deps(const char *filename, struct op op[], unsigned int num)
 496 {
 497 #ifdef DEBUG_DEPS
 498         unsigned int i;
 499
 500         for (i = 1; i < num; i++)
 501                 if (!list_empty(&op[i].pre))
 502                         fail(filename, i+1, "Still has dependencies");
 503 #endif
 504 }
 505
 506 static void dump_pre(char *filename[], struct op *op[],
 507                      unsigned int file, unsigned int i)
 508 {
 509         struct depend *dep;
 510
 511         if (!quiet) {
 512                 printf("%s:%u (%u) still waiting for:\n", filename[file], i+1,
 513                        op[file][i].seqnum);
 514                 list_for_each(&op[file][i].pre, dep, pre_list)
 515                         printf("    %s:%u (%u)\n",
 516                                filename[dep->prereq.file], dep->prereq.op_num+1,
 517                                op[dep->prereq.file][dep->prereq.op_num].seqnum);
 518         }
 519         check_deps(filename[file], op[file], i);
 520 }
 521
 522 /* We simply read/write pointers, since we all are children. */
 523 static bool do_pre(struct tdb_context *tdb,
 524                    char *filename[], struct op *op[],
 525                    unsigned int file, int pre_fd, unsigned int i,
 526                    bool backoff)
 527 {
 528         while (!list_empty(&op[file][i].pre)) {
 529                 struct depend *dep;
 530
 531 #if DEBUG_DEPS
 532                 printf("%s:%u:waiting for pre\n", filename[file], i+1);
 533                 fflush(stdout);
 534 #endif
 535                 if (backoff)
 536                         alarm(2);
 537                 else
 538                         alarm(10);
 539                 while (read(pre_fd, &dep, sizeof(dep)) != sizeof(dep)) {
 540                         if (errno == EINTR) {
 541                                 if (backoff) {
 542                                         struct op_desc desc = { file,i };
 543                                         warnx("%s:%u:avoiding deadlock",
 544                                               filename[file], i+1);
 545                                         if (write(backoff_fd, &desc,
 546                                                   sizeof(desc)) != sizeof(desc))
 547                                                 err(1, "writing backoff_fd");
 548                                         return false;
 549                                 }
 550                                 dump_pre(filename, op, file, i);
 551                                 exit(1);
 552                         } else
 553                                 errx(1, "Reading from pipe");
 554                 }
 555                 alarm(0);
 556
 557 #if DEBUG_DEPS
 558                 printf("%s:%u:got pre %u from %s:%u\n", filename[file], i+1,
 559                        dep->needs.op_num+1, filename[dep->prereq.file],
 560                        dep->prereq.op_num+1);
 561                 fflush(stdout);
 562 #endif
 563                 /* This could be any op, not just this one. */
 564                 talloc_free(dep);
 565         }
 566         return true;
 567 }
 568
 569 static void do_post(char *filename[], struct op *op[],
 570                     unsigned int file, unsigned int i)
 571 {
 572         struct depend *dep;
 573
 574         list_for_each(&op[file][i].post, dep, post_list) {
 575 #if DEBUG_DEPS
 576                 printf("%s:%u:sending to file %s:%u\n", filename[file], i+1,
 577                        filename[dep->needs.file], dep->needs.op_num+1);
 578 #endif
 579                 if (write(pipes[dep->needs.file].fd[1], &dep, sizeof(dep))
 580                     != sizeof(dep))
 581                         err(1, "%s:%u failed to tell file %s",
 582                             filename[file], i+1, filename[dep->needs.file]);
 583         }
 584 }
 585
 586 static int get_len(TDB_DATA key, TDB_DATA data, void *private_data)
 587 {
 588         return data.dsize;
 589 }
 590
 591 static unsigned run_ops(struct tdb_context *tdb,
 592                         int pre_fd,
 593                         char *filename[],
 594                         struct op *op[],
 595                         unsigned int file,
 596                         unsigned int start, unsigned int stop,
 597                         bool backoff);
 598
 599 struct traverse_info {
 600         struct op **op;
 601         char **filename;
 602         unsigned file;
 603         int pre_fd;
 604         unsigned int start;
 605         unsigned int i;
 606 };
 607
 608 /* More complex.  Just do whatever's they did at the n'th entry. */
 609 static int nontrivial_traverse(struct tdb_context *tdb,
 610                                TDB_DATA key, TDB_DATA data,
 611                                void *_tinfo)
 612 {
 613         struct traverse_info *tinfo = _tinfo;
 614         unsigned int trav_len = tinfo->op[tinfo->file][tinfo->start].group_len;
 615         bool avoid_deadlock = false;
 616
 617         if (tinfo->i == tinfo->start + trav_len) {
 618                 /* This can happen if traverse expects to be empty. */
 619                 if (trav_len == 1)
 620                         return 1;
 621                 fail(tinfo->filename[tinfo->file], tinfo->start + 1,
 622                      "traverse did not terminate");
 623         }
 624
 625         if (tinfo->op[tinfo->file][tinfo->i].type != OP_TDB_TRAVERSE)
 626                 fail(tinfo->filename[tinfo->file], tinfo->start + 1,
 627                      "%s:%u:traverse terminated early");
 628
 629 #if TRAVERSALS_TAKE_TRANSACTION_LOCK
 630         avoid_deadlock = true;
 631 #endif
 632
 633         /* Run any normal ops. */
 634         tinfo->i = run_ops(tdb, tinfo->pre_fd, tinfo->filename, tinfo->op,
 635                            tinfo->file, tinfo->i+1, tinfo->start + trav_len,
 636                            avoid_deadlock);
 637
 638         /* We backed off, or we hit OP_TDB_TRAVERSE_END/EARLY. */
 639         if (tinfo->op[tinfo->file][tinfo->i].type != OP_TDB_TRAVERSE)
 640                 return 1;
 641
 642         return 0;
 643 }
 644
 645 static unsigned op_traverse(struct tdb_context *tdb,
 646                             int pre_fd,
 647                             char *filename[],
 648                             unsigned int file,
 649                             int (*traversefn)(struct tdb_context *,
 650                                               tdb_traverse_func, void *),
 651                             struct op *op[],
 652                             unsigned int start)
 653 {
 654         struct traverse_info tinfo = { op, filename, file, pre_fd,
 655                                        start, start+1 };
 656
 657         traversefn(tdb, nontrivial_traverse, &tinfo);
 658
 659         /* Traversing in wrong order can have strange effects: eg. if
 660          * original traverse went A (delete A), B, we might do B
 661          * (delete A).  So if we have ops left over, we do it now. */
 662         while (tinfo.i != start + op[file][start].group_len) {
 663                 if (op[file][tinfo.i].type == OP_TDB_TRAVERSE
 664                     || op[file][tinfo.i].type == OP_TDB_TRAVERSE_END_EARLY)
 665                         tinfo.i++;
 666                 else
 667                         tinfo.i = run_ops(tdb, pre_fd, filename, op, file,
 668                                           tinfo.i,
 669                                           start + op[file][start].group_len,
 670                                           false);
 671         }
 672
 673         return tinfo.i;
 674 }
 675
 676 static void break_out(int sig)
 677 {
 678 }
 679
 680 static __attribute__((noinline))
 681 unsigned run_ops(struct tdb_context *tdb,
 682                  int pre_fd,
 683                  char *filename[],
 684                  struct op *op[],
 685                  unsigned int file,
 686                  unsigned int start, unsigned int stop,
 687                  bool backoff)
 688 {
 689         unsigned int i;
 690         struct sigaction sa;
 691
 692         sa.sa_handler = break_out;
 693         sa.sa_flags = 0;
 694
 695         sigaction(SIGALRM, &sa, NULL);
 696         for (i = start; i < stop; i++) {
 697                 if (!do_pre(tdb, filename, op, file, pre_fd, i, backoff))
 698                         return i;
 699
 700                 switch (op[file][i].type) {
 701                 case OP_TDB_LOCKALL:
 702                         try(tdb_lockall(tdb), op[file][i].ret);
 703                         break;
 704                 case OP_TDB_LOCKALL_MARK:
 705                         try(tdb_lockall_mark(tdb), op[file][i].ret);
 706                         break;
 707                 case OP_TDB_LOCKALL_UNMARK:
 708                         try(tdb_lockall_unmark(tdb), op[file][i].ret);
 709                         break;
 710                 case OP_TDB_LOCKALL_NONBLOCK:
 711                         unreliable(tdb_lockall_nonblock(tdb), op[file][i].ret,
 712                                    tdb_lockall(tdb), tdb_unlockall(tdb));
 713                         break;
 714                 case OP_TDB_UNLOCKALL:
 715                         try(tdb_unlockall(tdb), op[file][i].ret);
 716                         break;
 717                 case OP_TDB_LOCKALL_READ:
 718                         try(tdb_lockall_read(tdb), op[file][i].ret);
 719                         break;
 720                 case OP_TDB_LOCKALL_READ_NONBLOCK:
 721                         unreliable(tdb_lockall_read_nonblock(tdb),
 722                                    op[file][i].ret,
 723                                    tdb_lockall_read(tdb),
 724                                    tdb_unlockall_read(tdb));
 725                         break;
 726                 case OP_TDB_UNLOCKALL_READ:
 727                         try(tdb_unlockall_read(tdb), op[file][i].ret);
 728                         break;
 729                 case OP_TDB_CHAINLOCK:
 730                         try(tdb_chainlock(tdb, op[file][i].key),
 731                             op[file][i].ret);
 732                         break;
 733                 case OP_TDB_CHAINLOCK_NONBLOCK:
 734                         unreliable(tdb_chainlock_nonblock(tdb, op[file][i].key),
 735                                    op[file][i].ret,
 736                                    tdb_chainlock(tdb, op[file][i].key),
 737                                    tdb_chainunlock(tdb, op[file][i].key));
 738                         break;
 739                 case OP_TDB_CHAINLOCK_MARK:
 740                         try(tdb_chainlock_mark(tdb, op[file][i].key),
 741                             op[file][i].ret);
 742                         break;
 743                 case OP_TDB_CHAINLOCK_UNMARK:
 744                         try(tdb_chainlock_unmark(tdb, op[file][i].key),
 745                             op[file][i].ret);
 746                         break;
 747                 case OP_TDB_CHAINUNLOCK:
 748                         try(tdb_chainunlock(tdb, op[file][i].key),
 749                             op[file][i].ret);
 750                         break;
 751                 case OP_TDB_CHAINLOCK_READ:
 752                         try(tdb_chainlock_read(tdb, op[file][i].key),
 753                             op[file][i].ret);
 754                         break;
 755                 case OP_TDB_CHAINUNLOCK_READ:
 756                         try(tdb_chainunlock_read(tdb, op[file][i].key),
 757                             op[file][i].ret);
 758                         break;
 759                 case OP_TDB_PARSE_RECORD:
 760                         try(tdb_parse_record(tdb, op[file][i].key, get_len,
 761                                              NULL),
 762                             op[file][i].ret);
 763                         break;
 764                 case OP_TDB_EXISTS:
 765                         try(tdb_exists(tdb, op[file][i].key), op[file][i].ret);
 766                         break;
 767                 case OP_TDB_STORE:
 768                         try(tdb_store(tdb, op[file][i].key, op[file][i].data,
 769                                       op[file][i].flag),
 770                             op[file][i].ret);
 771                         break;
 772                 case OP_TDB_APPEND:
 773                         try(tdb_append(tdb, op[file][i].key, op[file][i].data),
 774                             op[file][i].ret);
 775                         break;
 776                 case OP_TDB_GET_SEQNUM:
 777                         try(tdb_get_seqnum(tdb), op[file][i].ret);
 778                         break;
 779                 case OP_TDB_WIPE_ALL:
 780                         try(tdb_wipe_all(tdb), op[file][i].ret);
 781                         break;
 782                 case OP_TDB_TRANSACTION_START:
 783                         try(tdb_transaction_start(tdb), op[file][i].ret);
 784                         break;
 785                 case OP_TDB_TRANSACTION_CANCEL:
 786                         try(tdb_transaction_cancel(tdb), op[file][i].ret);
 787                         break;
 788                 case OP_TDB_TRANSACTION_PREPARE_COMMIT:
 789                         try(tdb_transaction_prepare_commit(tdb),
 790                             op[file][i].ret);
 791                         break;
 792                 case OP_TDB_TRANSACTION_COMMIT:
 793                         try(tdb_transaction_commit(tdb), op[file][i].ret);
 794                         break;
 795                 case OP_TDB_TRAVERSE_READ_START:
 796                         i = op_traverse(tdb, pre_fd, filename, file,
 797                                         tdb_traverse_read, op, i);
 798                         break;
 799                 case OP_TDB_TRAVERSE_START:
 800                         i = op_traverse(tdb, pre_fd, filename, file,
 801                                         tdb_traverse, op, i);
 802                         break;
 803                 case OP_TDB_TRAVERSE:
 804                 case OP_TDB_TRAVERSE_END_EARLY:
 805                         /* Terminate: we're in a traverse, and we've
 806                          * done our ops. */
 807                         return i;
 808                 case OP_TDB_TRAVERSE_END:
 809                         fail(filename[file], i+1, "unexpected end traverse");
 810                 /* FIXME: These must be treated like traverse. */
 811                 case OP_TDB_FIRSTKEY:
 812                         if (!key_eq(tdb_firstkey(tdb), op[file][i].data))
 813                                 fail(filename[file], i+1, "bad firstkey");
 814                         break;
 815                 case OP_TDB_NEXTKEY:
 816                         if (!key_eq(tdb_nextkey(tdb, op[file][i].key),
 817                                     op[file][i].data))
 818                                 fail(filename[file], i+1, "bad nextkey");
 819                         break;
 820                 case OP_TDB_FETCH: {
 821                         TDB_DATA f = tdb_fetch(tdb, op[file][i].key);
 822                         if (!key_eq(f, op[file][i].data))
 823                                 fail(filename[file], i+1, "bad fetch %u",
 824                                      f.dsize);
 825                         break;
 826                 }
 827                 case OP_TDB_DELETE:
 828                         try(tdb_delete(tdb, op[file][i].key), op[file][i].ret);
 829                         break;
 830                 case OP_TDB_REPACK:
 831                         /* We do nothing here: the transaction and traverse are
 832                          * traced.  It's in the trace to mark it, since it
 833                          * may become unnecessary in future. */
 834                         break;
 835                 }
 836                 do_post(filename, op, file, i);
 837         }
 838         return i;
 839 }
 840
 841 /* tdbtorture, in particular, can do a tdb_close with a transaction in
 842  * progress. */
 843 static struct op *maybe_cancel_transaction(char *filename[], unsigned int file,
 844                                            struct op *op, unsigned int *num)
 845 {
 846         unsigned int start = op_find_start(op, *num, OP_TDB_TRANSACTION_START);
 847
 848         if (start) {
 849                 char *words[] = { "<unknown>", "tdb_close", NULL };
 850                 add_op(filename[file], &op, *num, op[start].seqnum,
 851                        OP_TDB_TRANSACTION_CANCEL);
 852                 op_analyze_transaction(filename, op, file, *num, words);
 853                 (*num)++;
 854         }
 855         return op;
 856 }
 857
 858 static struct op *load_tracefile(char *filename[],
 859                                  unsigned int file,
 860                                  unsigned int *num,
 861                                  unsigned int *hashsize,
 862                                  unsigned int *tdb_flags,
 863                                  unsigned int *open_flags)
 864 {
 865         unsigned int i;
 866         struct op *op = talloc_array(NULL, struct op, 1);
 867         char **words;
 868         char **lines;
 869         char *contents;
 870
 871         contents = grab_file(NULL, filename[file], NULL);
 872         if (!contents)
 873                 err(1, "Reading %s", filename[file]);
 874
 875         lines = strsplit(contents, contents, "\n");
 876         if (!lines[0])
 877                 errx(1, "%s is empty", filename[file]);
 878
 879         words = strsplit(lines, lines[0], " ");
 880         if (!streq(words[1], "tdb_open"))
 881                 fail(filename[file], 1, "does not start with tdb_open");
 882
 883         *hashsize = atoi(words[2]);
 884         *tdb_flags = strtoul(words[3], NULL, 0);
 885         *open_flags = strtoul(words[4], NULL, 0);
 886
 887         for (i = 1; lines[i]; i++) {
 888                 const struct op_table *opt;
 889
 890                 words = strsplit(lines, lines[i], " ");
 891                 if (!words[0] || !words[1])
 892                         fail(filename[file], i+1,
 893                              "Expected seqnum number and op");
 894
 895                 opt = find_keyword(words[1], strlen(words[1]));
 896                 if (!opt) {
 897                         if (streq(words[1], "tdb_close")) {
 898                                 if (lines[i+1])
 899                                         fail(filename[file], i+2,
 900                                              "lines after tdb_close");
 901                                 *num = i;
 902                                 talloc_free(lines);
 903                                 return maybe_cancel_transaction(filename, file,
 904                                                                 op, num);
 905                         }
 906                         fail(filename[file], i+1,
 907                              "Unknown operation '%s'", words[1]);
 908                 }
 909
 910                 add_op(filename[file], &op, i, atoi(words[0]), opt->type);
 911                 opt->enhance_op(filename, op, file, i, words);
 912         }
 913
 914         if (!quiet)
 915                 fprintf(stderr,
 916                         "%s:%u:last operation is not tdb_close: incomplete?",
 917                         filename[file], i);
 918
 919         talloc_free(contents);
 920         *num = i - 1;
 921         return maybe_cancel_transaction(filename, file, op, num);
 922 }
 923
 924 /* We remember all the keys we've ever seen, and who has them. */
 925 struct keyinfo {
 926         TDB_DATA key;
 927         unsigned int num_users;
 928         struct op_desc *user;
 929 };
 930
 931 static bool starts_transaction(const struct op *op)
 932 {
 933         return op->type == OP_TDB_TRANSACTION_START;
 934 }
 935
 936 static bool in_transaction(const struct op op[], unsigned int i)
 937 {
 938         return op[i].group_start && starts_transaction(&op[op[i].group_start]);
 939 }
 940
 941 static bool successful_transaction(const struct op *op)
 942 {
 943         return starts_transaction(op)
 944                 && op[op->group_len].type == OP_TDB_TRANSACTION_COMMIT;
 945 }
 946
 947 static bool starts_traverse(const struct op *op)
 948 {
 949         return op->type == OP_TDB_TRAVERSE_START
 950                 || op->type == OP_TDB_TRAVERSE_READ_START;
 951 }
 952
 953 static bool in_traverse(const struct op op[], unsigned int i)
 954 {
 955         return op[i].group_start && starts_traverse(&op[op[i].group_start]);
 956 }
 957
 958 static bool starts_chainlock(const struct op *op)
 959 {
 960         return op->type == OP_TDB_CHAINLOCK_READ
 961                 || op->type == OP_TDB_CHAINLOCK;
 962 }
 963
 964 static bool in_chainlock(const struct op op[], unsigned int i)
 965 {
 966         return op[i].group_start && starts_chainlock(&op[op[i].group_start]);
 967 }
 968
 969 static const TDB_DATA must_not_exist;
 970 static const TDB_DATA must_exist;
 971 static const TDB_DATA not_exists_or_empty;
 972
 973 /* NULL means doesn't care if it exists or not, &must_exist means
 974  * it must exist but we don't care what, &must_not_exist means it must
 975  * not exist, otherwise the data it needs. */
 976 static const TDB_DATA *needs(const TDB_DATA *key, const struct op *op)
 977 {
 978         /* Look through for an op in this transaction which needs this key. */
 979         if (starts_transaction(op) || starts_chainlock(op)) {
 980                 unsigned int i;
 981                 const TDB_DATA *need = NULL;
 982
 983                 for (i = 1; i < op->group_len; i++) {
 984                         if (key_eq(op[i].key, *key)
 985                             || op[i].type == OP_TDB_WIPE_ALL) {
 986                                 need = needs(key, &op[i]);
 987                                 /* tdb_exists() is special: there might be
 988                                  * something in the transaction with more
 989                                  * specific requirements.  Other ops don't have
 990                                  * specific requirements (eg. store or delete),
 991                                  * but they change the value so we can't get
 992                                  * more information from future ops. */
 993                                 if (op[i].type != OP_TDB_EXISTS)
 994                                         break;
 995                         }
 996                 }
 997
 998                 return need;
 999         }
1000
1001         switch (op->type) {
1002         /* FIXME: Pull forward deps, since we can deadlock */
1003         case OP_TDB_CHAINLOCK:
1004         case OP_TDB_CHAINLOCK_NONBLOCK:
1005         case OP_TDB_CHAINLOCK_MARK:
1006         case OP_TDB_CHAINLOCK_UNMARK:
1007         case OP_TDB_CHAINUNLOCK:
1008         case OP_TDB_CHAINLOCK_READ:
1009         case OP_TDB_CHAINUNLOCK_READ:
1010                 return NULL;
1011
1012         case OP_TDB_APPEND:
1013                 if (op->append.pre.dsize == 0)
1014                         return &not_exists_or_empty;
1015                 return &op->append.pre;
1016
1017         case OP_TDB_STORE:
1018                 if (op->flag == TDB_INSERT) {
1019                         if (op->ret < 0)
1020                                 return &must_exist;
1021                         else
1022                                 return &must_not_exist;
1023                 } else if (op->flag == TDB_MODIFY) {
1024                         if (op->ret < 0)
1025                                 return &must_not_exist;
1026                         else
1027                                 return &must_exist;
1028                 }
1029                 /* No flags?  Don't care */
1030                 return NULL;
1031
1032         case OP_TDB_EXISTS:
1033                 if (op->ret == 1)
1034                         return &must_exist;
1035                 else
1036                         return &must_not_exist;
1037
1038         case OP_TDB_PARSE_RECORD:
1039                 if (op->ret < 0)
1040                         return &must_not_exist;
1041                 return &must_exist;
1042
1043         /* FIXME: handle these. */
1044         case OP_TDB_WIPE_ALL:
1045         case OP_TDB_FIRSTKEY:
1046         case OP_TDB_NEXTKEY:
1047         case OP_TDB_GET_SEQNUM:
1048         case OP_TDB_TRAVERSE:
1049         case OP_TDB_TRANSACTION_COMMIT:
1050         case OP_TDB_TRANSACTION_CANCEL:
1051         case OP_TDB_TRANSACTION_START:
1052                 return NULL;
1053
1054         case OP_TDB_FETCH:
1055                 if (!op->data.dptr)
1056                         return &must_not_exist;
1057                 return &op->data;
1058
1059         case OP_TDB_DELETE:
1060                 if (op->ret < 0)
1061                         return &must_not_exist;
1062                 return &must_exist;
1063
1064         default:
1065                 errx(1, "Unexpected op type %i", op->type);
1066         }
1067
1068 }
1069
1070 /* What's the data after this op?  pre if nothing changed. */
1071 static const TDB_DATA *gives(const TDB_DATA *key, const TDB_DATA *pre,
1072                              const struct op *op)
1073 {
1074         if (starts_transaction(op) || starts_chainlock(op)) {
1075                 unsigned int i;
1076
1077                 /* Cancelled transactions don't change anything. */
1078                 if (op[op->group_len].type == OP_TDB_TRANSACTION_CANCEL)
1079                         return pre;
1080                 assert(op[op->group_len].type == OP_TDB_TRANSACTION_COMMIT
1081                        || op[op->group_len].type == OP_TDB_CHAINUNLOCK_READ
1082                        || op[op->group_len].type == OP_TDB_CHAINUNLOCK);
1083
1084                 for (i = 1; i < op->group_len; i++) {
1085                         /* This skips nested transactions, too */
1086                         if (key_eq(op[i].key, *key)
1087                             || op[i].type == OP_TDB_WIPE_ALL)
1088                                 pre = gives(key, pre, &op[i]);
1089                 }
1090                 return pre;
1091         }
1092
1093         /* Failed ops don't change state of db. */
1094         if (op->ret < 0)
1095                 return pre;
1096
1097         if (op->type == OP_TDB_DELETE || op->type == OP_TDB_WIPE_ALL)
1098                 return &tdb_null;
1099
1100         if (op->type == OP_TDB_APPEND)
1101                 return &op->append.post;
1102
1103         if (op->type == OP_TDB_STORE)
1104                 return &op->data;
1105
1106         return pre;
1107 }
1108
1109 static void add_hash_user(struct keyinfo *hash,
1110                           unsigned int h,
1111                           struct op *op[],
1112                           unsigned int file,
1113                           unsigned int op_num)
1114 {
1115         hash[h].user = talloc_realloc(hash, hash[h].user,
1116                                       struct op_desc, hash[h].num_users+1);
1117
1118         /* If it's in a transaction, it's the transaction which
1119          * matters from an analysis POV. */
1120         if (in_transaction(op[file], op_num)
1121             || in_chainlock(op[file], op_num)) {
1122                 unsigned i;
1123
1124                 op_num = op[file][op_num].group_start;
1125
1126                 /* Don't include twice. */
1127                 for (i = 0; i < hash[h].num_users; i++) {
1128                         if (hash[h].user[i].file == file
1129                             && hash[h].user[i].op_num == op_num)
1130                                 return;
1131                 }
1132         }
1133         hash[h].user[hash[h].num_users].op_num = op_num;
1134         hash[h].user[hash[h].num_users].file = file;
1135         hash[h].num_users++;
1136 }
1137
1138 static struct keyinfo *hash_ops(struct op *op[], unsigned int num_ops[],
1139                                 unsigned int num)
1140 {
1141         unsigned int i, j, h;
1142         struct keyinfo *hash;
1143
1144         hash = talloc_zero_array(op[0], struct keyinfo, total_keys*2);
1145         for (i = 0; i < num; i++) {
1146                 for (j = 1; j < num_ops[i]; j++) {
1147                         /* We can't do this on allocation, due to realloc. */
1148                         list_head_init(&op[i][j].post);
1149                         list_head_init(&op[i][j].pre);
1150
1151                         if (!op[i][j].key.dptr)
1152                                 continue;
1153
1154                         h = hash_key(&op[i][j].key) % (total_keys * 2);
1155                         while (!key_eq(hash[h].key, op[i][j].key)) {
1156                                 if (!hash[h].key.dptr) {
1157                                         hash[h].key = op[i][j].key;
1158                                         break;
1159                                 }
1160                                 h = (h + 1) % (total_keys * 2);
1161                         }
1162                         /* Might as well save some memory if we can. */
1163                         if (op[i][j].key.dptr != hash[h].key.dptr) {
1164                                 talloc_free(op[i][j].key.dptr);
1165                                 op[i][j].key.dptr = hash[h].key.dptr;
1166                         }
1167
1168                         add_hash_user(hash, h, op, i, j);
1169                 }
1170         }
1171
1172         /* Any wipe all entries need adding to all hash entries. */
1173         for (h = 0; h < total_keys*2; h++) {
1174                 if (!hash[h].num_users)
1175                         continue;
1176
1177                 for (i = 0; i < num_wipe_alls; i++)
1178                         add_hash_user(hash, h, op,
1179                                       wipe_alls[i].file, wipe_alls[i].op_num);
1180         }
1181
1182         return hash;
1183 }
1184
1185 static bool satisfies(const TDB_DATA *key, const TDB_DATA *data,
1186                       const struct op *op)
1187 {
1188         const TDB_DATA *need = needs(key, op);
1189
1190         /* Don't need anything?  Cool. */
1191         if (!need)
1192                 return true;
1193
1194         /* This should be tdb_null or a real value. */
1195         assert(data != &must_exist);
1196         assert(data != &must_not_exist);
1197         assert(data != &not_exists_or_empty);
1198
1199         /* Must not exist?  data must not exist. */
1200         if (need == &must_not_exist)
1201                 return data == &tdb_null;
1202
1203         /* Must exist? */
1204         if (need == &must_exist)
1205                 return data != &tdb_null;
1206
1207         /* Either noexist or empty. */
1208         if (need == &not_exists_or_empty)
1209                 return data->dsize == 0;
1210
1211         /* Needs something specific. */
1212         return key_eq(*data, *need);
1213 }
1214
1215 static void move_to_front(struct op_desc res[], unsigned off, unsigned elem)
1216 {
1217         if (elem != off) {
1218                 struct op_desc tmp = res[elem];
1219                 memmove(res + off + 1, res + off, (elem - off)*sizeof(res[0]));
1220                 res[off] = tmp;
1221         }
1222 }
1223
1224 static void restore_to_pos(struct op_desc res[], unsigned off, unsigned elem)
1225 {
1226         if (elem != off) {
1227                 struct op_desc tmp = res[off];
1228                 memmove(res + off, res + off + 1, (elem - off)*sizeof(res[0]));
1229                 res[elem] = tmp;
1230         }
1231 }
1232
1233 static bool sort_deps(char *filename[], struct op *op[],
1234                       struct op_desc res[],
1235                       unsigned off, unsigned num,
1236                       const TDB_DATA *key, const TDB_DATA *data,
1237                       unsigned num_files, unsigned fuzz)
1238 {
1239         unsigned int i, files_done;
1240         struct op *this_op;
1241         bool done[num_files];
1242
1243         /* None left?  We're sorted. */
1244         if (off == num)
1245                 return true;
1246
1247         /* Does this make sequence number go backwards?  Allow a little fuzz. */
1248         if (off > 0) {
1249                 int seqnum1 = op[res[off-1].file][res[off-1].op_num].seqnum;
1250                 int seqnum2 = op[res[off].file][res[off].op_num].seqnum;
1251
1252                 if (seqnum1 - seqnum2 > (int)fuzz) {
1253 #if DEBUG_DEPS
1254                         printf("Seqnum jump too far (%u -> %u)\n",
1255                                seqnum1, seqnum2);
1256 #endif
1257                         return false;
1258                 }
1259         }
1260
1261         memset(done, 0, sizeof(done));
1262
1263         /* Since ops within a trace file are ordered, we just need to figure
1264          * out which file to try next.  Since we don't take into account
1265          * inter-key relationships (which exist by virtue of trace file order),
1266          * we minimize the chance of harm by trying to keep in seqnum order. */
1267         for (files_done = 0, i = off; i < num && files_done < num_files; i++) {
1268                 if (done[res[i].file])
1269                         continue;
1270
1271                 this_op = &op[res[i].file][res[i].op_num];
1272
1273                 /* Is what we have good enough for this op? */
1274                 if (satisfies(key, data, this_op)) {
1275                         move_to_front(res, off, i);
1276                         if (sort_deps(filename, op, res, off+1, num,
1277                                       key, gives(key, data, this_op),
1278                                       num_files, fuzz))
1279                                 return true;
1280                         restore_to_pos(res, off, i);
1281                 }
1282                 done[res[i].file] = true;
1283                 files_done++;
1284         }
1285
1286         /* No combination worked. */
1287         return false;
1288 }
1289
1290 static void check_dep_sorting(struct op_desc user[], unsigned num_users,
1291                               unsigned num_files)
1292 {
1293 #if DEBUG_DEPS
1294         unsigned int i;
1295         unsigned minima[num_files];
1296
1297         memset(minima, 0, sizeof(minima));
1298         for (i = 0; i < num_users; i++) {
1299                 assert(minima[user[i].file] < user[i].op_num);
1300                 minima[user[i].file] = user[i].op_num;
1301         }
1302 #endif
1303 }
1304
1305 /* All these ops happen on the same key.  Which comes first?
1306  *
1307  * This can happen both because read ops or failed write ops don't
1308  * change sequence number, and also due to race since we access the
1309  * number unlocked (the race can cause less detectable ordering problems,
1310  * in which case we'll deadlock and report: fix manually in that case).
1311  */
1312 static bool figure_deps(char *filename[], struct op *op[],
1313                         const TDB_DATA *key, const TDB_DATA *data,
1314                         struct op_desc user[],
1315                         unsigned num_users, unsigned num_files)
1316 {
1317         unsigned int fuzz;
1318
1319         /* We prefer to keep strict seqnum order if possible: it's the
1320          * most likely.  We get more lax if that fails. */
1321         for (fuzz = 0; fuzz < 100; fuzz = (fuzz + 1)*2) {
1322                 if (sort_deps(filename, op, user, 0, num_users, key, data,
1323                               num_files, fuzz))
1324                         break;
1325         }
1326
1327         if (fuzz >= 100)
1328                 return false;
1329
1330         check_dep_sorting(user, num_users, num_files);
1331         return true;
1332 }
1333
1334 /* We're having trouble sorting out dependencies for this key.  Assume that it's
1335  * a pre-existing record in the db, so determine a likely value. */
1336 static const TDB_DATA *preexisting_data(char *filename[], struct op *op[],
1337                                         const TDB_DATA *key,
1338                                         struct op_desc *user,
1339                                         unsigned int num_users)
1340 {
1341         unsigned int i;
1342         const TDB_DATA *data;
1343
1344         for (i = 0; i < num_users; i++) {
1345                 data = needs(key, &op[user->file][user->op_num]);
1346                 if (data && data != &must_not_exist) {
1347                         if (!quiet)
1348                                 printf("%s:%u: needs pre-existing record\n",
1349                                        filename[user->file], user->op_num+1);
1350                         return data;
1351                 }
1352         }
1353         return &tdb_null;
1354 }
1355
1356 static void sort_ops(struct tdb_context *tdb,
1357                      struct keyinfo hash[], char *filename[], struct op *op[],
1358                      unsigned int num)
1359 {
1360         unsigned int h;
1361
1362         /* Gcc nexted function extension.  How cool is this? */
1363         int compare_seqnum(const void *_a, const void *_b)
1364         {
1365                 const struct op_desc *a = _a, *b = _b;
1366
1367                 /* First, maintain order within any trace file. */
1368                 if (a->file == b->file)
1369                         return a->op_num - b->op_num;
1370
1371                 /* Otherwise, arrange by seqnum order. */
1372                 if (op[a->file][a->op_num].seqnum !=
1373                     op[b->file][b->op_num].seqnum)
1374                         return op[a->file][a->op_num].seqnum
1375                                 - op[b->file][b->op_num].seqnum;
1376
1377                 /* Cancelled transactions are assumed to happen first. */
1378                 if (starts_transaction(&op[a->file][a->op_num])
1379                     && !successful_transaction(&op[a->file][a->op_num]))
1380                         return -1;
1381                 if (starts_transaction(&op[b->file][b->op_num])
1382                     && !successful_transaction(&op[b->file][b->op_num]))
1383                         return 1;
1384
1385                 /* No idea. */
1386                 return 0;
1387         }
1388
1389         /* Now sort into seqnum order. */
1390         for (h = 0; h < total_keys * 2; h++) {
1391                 struct op_desc *user = hash[h].user;
1392
1393                 qsort(user, hash[h].num_users, sizeof(user[0]), compare_seqnum);
1394                 if (!figure_deps(filename, op, &hash[h].key, &tdb_null, user,
1395                                  hash[h].num_users, num)) {
1396                         const TDB_DATA *data;
1397
1398                         data = preexisting_data(filename, op, &hash[h].key,
1399                                                 user, hash[h].num_users);
1400                         /* Give the first op what it wants: does that help? */
1401                         if (!figure_deps(filename, op, &hash[h].key, data, user,
1402                                          hash[h].num_users, num))
1403                                 fail(filename[user[0].file], user[0].op_num+1,
1404                                      "Could not resolve inter-dependencies");
1405                         if (tdb_store(tdb, hash[h].key, *data, TDB_INSERT) != 0)
1406                                 errx(1, "Could not store initial value");
1407                 }
1408         }
1409 }
1410
1411 static int destroy_depend(struct depend *dep)
1412 {
1413         list_del(&dep->pre_list);
1414         list_del(&dep->post_list);
1415         return 0;
1416 }
1417
1418 static void add_dependency(void *ctx,
1419                            struct op *op[],
1420                            char *filename[],
1421                            const struct op_desc *needs,
1422                            const struct op_desc *prereq)
1423 {
1424         struct depend *dep;
1425
1426         /* We don't depend on ourselves. */
1427         if (needs->file == prereq->file) {
1428                 assert(prereq->op_num < needs->op_num);
1429                 return;
1430         }
1431
1432 #if DEBUG_DEPS
1433         printf("%s:%u: depends on %s:%u\n",
1434                filename[needs->file], needs->op_num+1,
1435                filename[prereq->file], prereq->op_num+1);
1436 #endif
1437
1438         dep = talloc(ctx, struct depend);
1439         dep->needs = *needs;
1440         dep->prereq = *prereq;
1441
1442 #if TRAVERSALS_TAKE_TRANSACTION_LOCK
1443         /* If something in a traverse depends on something in another
1444          * traverse/transaction, it creates a dependency between the
1445          * two groups. */
1446         if ((in_traverse(op[prereq->file], prereq->op_num)
1447              && (starts_transaction(&op[needs->file][needs->op_num])
1448                  || starts_traverse(&op[needs->file][needs->op_num])))
1449             || (in_traverse(op[needs->file], needs->op_num)
1450                 && (starts_transaction(&op[prereq->file][prereq->op_num])
1451                     || starts_traverse(&op[prereq->file][prereq->op_num])))) {
1452                 unsigned int start;
1453
1454                 /* We are satisfied by end of group. */
1455                 start = op[prereq->file][prereq->op_num].group_start;
1456                 dep->prereq.op_num = start + op[prereq->file][start].group_len;
1457                 /* And we need that done by start of our group. */
1458                 dep->needs.op_num = op[needs->file][needs->op_num].group_start;
1459         }
1460
1461         /* There is also this case:
1462          *  <traverse> <read foo> ...
1463          *  <transaction> ... </transaction> <create foo>
1464          * Where if we start the traverse then wait, we could block
1465          * the transaction and deadlock.
1466          *
1467          * We try to address this by ensuring that where seqnum indicates it's
1468          * possible, we wait for <create foo> before *starting* traverse.
1469          */
1470         else if (in_traverse(op[needs->file], needs->op_num)) {
1471                 struct op *need = &op[needs->file][needs->op_num];
1472                 if (op[needs->file][need->group_start].seqnum >
1473                     op[prereq->file][prereq->op_num].seqnum) {
1474                         dep->needs.op_num = need->group_start;
1475                 }
1476         }
1477 #endif
1478
1479         /* If you depend on a transaction or chainlock, you actually
1480          * depend on it ending. */
1481         if (starts_transaction(&op[prereq->file][dep->prereq.op_num])
1482             || starts_chainlock(&op[prereq->file][dep->prereq.op_num])) {
1483                 dep->prereq.op_num
1484                         += op[dep->prereq.file][dep->prereq.op_num].group_len;
1485 #if DEBUG_DEPS
1486                 printf("-> Actually end of transaction %s:%u\n",
1487                        filename[dep->prereq->file], dep->prereq->op_num+1);
1488 #endif
1489         } else
1490                 /* We should never create a dependency from middle of
1491                  * a transaction. */
1492                 assert(!in_transaction(op[prereq->file], dep->prereq.op_num)
1493                        || op[prereq->file][dep->prereq.op_num].type
1494                        == OP_TDB_TRANSACTION_COMMIT
1495                        || op[prereq->file][dep->prereq.op_num].type
1496                        == OP_TDB_TRANSACTION_CANCEL);
1497
1498         list_add(&op[dep->prereq.file][dep->prereq.op_num].post,
1499                  &dep->post_list);
1500         list_add(&op[dep->needs.file][dep->needs.op_num].pre,
1501                  &dep->pre_list);
1502         talloc_set_destructor(dep, destroy_depend);
1503 }
1504
1505 static bool changes_db(const TDB_DATA *key, const struct op *op)
1506 {
1507         return gives(key, NULL, op) != NULL;
1508 }
1509
1510 static void depend_on_previous(struct op *op[],
1511                                char *filename[],
1512                                unsigned int num,
1513                                struct op_desc user[],
1514                                unsigned int i,
1515                                int prev)
1516 {
1517         bool deps[num];
1518         int j;
1519
1520         if (i == 0)
1521                 return;
1522
1523         if (prev == i - 1) {
1524                 /* Just depend on previous. */
1525                 add_dependency(NULL, op, filename, &user[i], &user[prev]);
1526                 return;
1527         }
1528
1529         /* We have to wait for the readers.  Find last one in *each* file. */
1530         memset(deps, 0, sizeof(deps));
1531         deps[user[i].file] = true;
1532         for (j = i - 1; j > prev; j--) {
1533                 if (!deps[user[j].file]) {
1534                         add_dependency(NULL, op, filename, &user[i], &user[j]);
1535                         deps[user[j].file] = true;
1536                 }
1537         }
1538 }
1539
1540 /* This is simple, but not complete.  We don't take into account
1541  * indirect dependencies. */
1542 static void optimize_dependencies(struct op *op[], unsigned int num_ops[],
1543                                   unsigned int num)
1544 {
1545         unsigned int i, j;
1546
1547         /* There can only be one real dependency on each file */
1548         for (i = 0; i < num; i++) {
1549                 for (j = 1; j < num_ops[i]; j++) {
1550                         struct depend *dep, *next;
1551                         struct depend *prev[num];
1552
1553                         memset(prev, 0, sizeof(prev));
1554
1555                         list_for_each_safe(&op[i][j].pre, dep, next, pre_list) {
1556                                 if (!prev[dep->prereq.file]) {
1557                                         prev[dep->prereq.file] = dep;
1558                                         continue;
1559                                 }
1560                                 if (prev[dep->prereq.file]->prereq.op_num
1561                                     < dep->prereq.op_num) {
1562                                         talloc_free(prev[dep->prereq.file]);
1563                                         prev[dep->prereq.file] = dep;
1564                                 } else
1565                                         talloc_free(dep);
1566                         }
1567                 }
1568         }
1569
1570         for (i = 0; i < num; i++) {
1571                 int deps[num];
1572
1573                 for (j = 0; j < num; j++)
1574                         deps[j] = -1;
1575
1576                 for (j = 1; j < num_ops[i]; j++) {
1577                         struct depend *dep, *next;
1578
1579                         list_for_each_safe(&op[i][j].pre, dep, next, pre_list) {
1580                                 if (deps[dep->prereq.file]
1581                                     >= (int)dep->prereq.op_num)
1582                                         talloc_free(dep);
1583                                 else
1584                                         deps[dep->prereq.file]
1585                                                 = dep->prereq.op_num;
1586                         }
1587                 }
1588         }
1589 }
1590
1591 #if TRAVERSALS_TAKE_TRANSACTION_LOCK
1592 /* Force an order among the traversals, so they don't deadlock (as much) */
1593 static void make_traverse_depends(char *filename[],
1594                                   struct op *op[], unsigned int num_ops[],
1595                                   unsigned int num)
1596 {
1597         unsigned int i, num_traversals = 0;
1598         int j;
1599         struct op_desc *desc;
1600
1601         /* Sort by which one runs first. */
1602         int compare_traverse_desc(const void *_a, const void *_b)
1603         {
1604                 const struct op_desc *da = _a, *db = _b;
1605                 const struct op *a = &op[da->file][da->op_num],
1606                         *b = &op[db->file][db->op_num];
1607
1608                 if (a->seqnum != b->seqnum)
1609                         return a->seqnum - b->seqnum;
1610
1611                 /* If they have same seqnum, it means one didn't make any
1612                  * changes.  Thus sort by end in that case. */
1613                 return a[a->group_len].seqnum - b[b->group_len].seqnum;
1614         }
1615
1616         desc = talloc_array(NULL, struct op_desc, 1);
1617
1618         /* Count them. */
1619         for (i = 0; i < num; i++) {
1620                 for (j = 1; j < num_ops[i]; j++) {
1621                         /* Traverse start (ignore those in
1622                          * transactions; they're already covered by
1623                          * transaction dependencies). */
1624                         if (starts_traverse(&op[i][j])
1625                             && !in_transaction(op[i], j)) {
1626                                 desc = talloc_realloc(NULL, desc,
1627                                                       struct op_desc,
1628                                                       num_traversals+1);
1629                                 desc[num_traversals].file = i;
1630                                 desc[num_traversals].op_num = j;
1631                                 num_traversals++;
1632                         }
1633                 }
1634         }
1635         qsort(desc, num_traversals, sizeof(desc[0]), compare_traverse_desc);
1636
1637         for (i = 1; i < num_traversals; i++) {
1638                 const struct op *prev = &op[desc[i-1].file][desc[i-1].op_num];
1639                 const struct op *curr = &op[desc[i].file][desc[i].op_num];
1640
1641                 /* Read traverses don't depend on each other (read lock). */
1642                 if (prev->type == OP_TDB_TRAVERSE_READ_START
1643                     && curr->type == OP_TDB_TRAVERSE_READ_START)
1644                         continue;
1645
1646                 /* Only make dependency if it's clear. */
1647                 if (compare_traverse_desc(&desc[i], &desc[i-1])) {
1648                         /* i depends on end of traverse i-1. */
1649                         struct op_desc end = desc[i-1];
1650                         end.op_num += prev->group_len;
1651                         add_dependency(NULL, op, filename, &desc[i], &end);
1652                 }
1653         }
1654         talloc_free(desc);
1655 }
1656
1657 static void set_nonblock(int fd)
1658 {
1659         if (fcntl(fd, F_SETFL, fcntl(fd, F_GETFL)|O_NONBLOCK) != 0)
1660                 err(1, "Setting pipe nonblocking");
1661 }
1662
1663 static bool handle_backoff(struct op *op[], int fd)
1664 {
1665         struct op_desc desc;
1666         bool handled = false;
1667
1668         /* Sloppy coding: we assume PIPEBUF never fills. */
1669         while (read(fd, &desc, sizeof(desc)) != -1) {
1670                 unsigned int i;
1671                 handled = true;
1672                 for (i = desc.op_num; i > 0; i--) {
1673                         if (op[desc.file][i].type == OP_TDB_TRAVERSE) {
1674                                 /* We insert a fake end here. */
1675                                 op[desc.file][i].type
1676                                         = OP_TDB_TRAVERSE_END_EARLY;
1677                                 break;
1678                         } else if (starts_traverse(&op[desc.file][i])) {
1679                                 unsigned int start = i;
1680                                 struct op tmp = op[desc.file][i];
1681                                 /* Move the ops outside traverse. */
1682                                 memmove(&op[desc.file][i],
1683                                         &op[desc.file][i+1],
1684                                         (desc.op_num-i-1) * sizeof(op[0][0]));
1685                                 op[desc.file][desc.op_num] = tmp;
1686                                 while (op[desc.file][i].group_start == start) {
1687                                         op[desc.file][i++].group_start
1688                                                 = desc.op_num;
1689                                 }
1690                                 break;
1691                         }
1692                 }
1693         }
1694         return handled;
1695 }
1696
1697 #else /* !TRAVERSALS_TAKE_TRANSACTION_LOCK */
1698 static bool handle_backoff(struct op *op[], int fd)
1699 {
1700         return false;
1701 }
1702 #endif
1703
1704 static void derive_dependencies(struct tdb_context *tdb,
1705                                 char *filename[],
1706                                 struct op *op[], unsigned int num_ops[],
1707                                 unsigned int num)
1708 {
1709         struct keyinfo *hash;
1710         unsigned int h, i;
1711
1712         /* Create hash table for faster key lookup. */
1713         hash = hash_ops(op, num_ops, num);
1714
1715         /* Sort them by sequence number. */
1716         sort_ops(tdb, hash, filename, op, num);
1717
1718         /* Create dependencies back to the last change, rather than
1719          * creating false dependencies by naively making each one
1720          * depend on the previous.  This has two purposes: it makes
1721          * later optimization simpler, and it also avoids deadlock with
1722          * same sequence number ops inside traversals (if one
1723          * traversal doesn't write anything, two ops can have the same
1724          * sequence number yet we can create a traversal dependency
1725          * the other way). */
1726         for (h = 0; h < total_keys * 2; h++) {
1727                 int prev = -1;
1728
1729                 if (hash[h].num_users < 2)
1730                         continue;
1731
1732                 for (i = 0; i < hash[h].num_users; i++) {
1733                         if (changes_db(&hash[h].key, &op[hash[h].user[i].file]
1734                                        [hash[h].user[i].op_num])) {
1735                                 depend_on_previous(op, filename, num,
1736                                                    hash[h].user, i, prev);
1737                                 prev = i;
1738                         } else if (prev >= 0)
1739                                 add_dependency(hash, op, filename,
1740                                                &hash[h].user[i],
1741                                                &hash[h].user[prev]);
1742                 }
1743         }
1744
1745 #if TRAVERSALS_TAKE_TRANSACTION_LOCK
1746         make_traverse_depends(filename, op, num_ops, num);
1747 #endif
1748
1749         optimize_dependencies(op, num_ops, num);
1750 }
1751
1752 static struct timeval run_test(char *argv[],
1753                                unsigned int num_ops[],
1754                                unsigned int hashsize[],
1755                                unsigned int tdb_flags[],
1756                                unsigned int open_flags[],
1757                                struct op *op[],
1758                                int fds[2])
1759 {
1760         unsigned int i;
1761         struct timeval start, end, diff;
1762         bool ok = true;
1763
1764         for (i = 0; argv[i+2]; i++) {
1765                 struct tdb_context *tdb;
1766                 char c;
1767
1768                 switch (fork()) {
1769                 case -1:
1770                         err(1, "fork failed");
1771                 case 0:
1772                         close(fds[1]);
1773                         tdb = tdb_open(argv[1], hashsize[i],
1774                                        tdb_flags[i], open_flags[i], 0600);
1775                         if (!tdb)
1776                                 err(1, "Opening tdb %s", argv[1]);
1777
1778                         /* This catches parent exiting. */
1779                         if (read(fds[0], &c, 1) != 1)
1780                                 exit(1);
1781                         run_ops(tdb, pipes[i].fd[0], argv+2, op, i, 1,
1782                                 num_ops[i], false);
1783                         check_deps(argv[2+i], op[i], num_ops[i]);
1784                         exit(0);
1785                 default:
1786                         break;
1787                 }
1788         }
1789
1790         /* Let everything settle. */
1791         sleep(1);
1792
1793         if (!quiet)
1794                 printf("Starting run...");
1795         fflush(stdout);
1796         gettimeofday(&start, NULL);
1797         /* Tell them all to go!  Any write of sufficient length will do. */
1798         if (write(fds[1], hashsize, i) != i)
1799                 err(1, "Writing to wakeup pipe");
1800
1801         for (i = 0; argv[i + 2]; i++) {
1802                 int status;
1803                 wait(&status);
1804                 if (!WIFEXITED(status)) {
1805                         warnx("Child died with signal %i", WTERMSIG(status));
1806                         ok = false;
1807                 } else if (WEXITSTATUS(status) != 0)
1808                         /* Assume child spat out error. */
1809                         ok = false;
1810         }
1811         if (!ok)
1812                 exit(1);
1813
1814         gettimeofday(&end, NULL);
1815         if (!quiet)
1816                 printf("done\n");
1817
1818         if (end.tv_usec < start.tv_usec) {
1819                 end.tv_usec += 1000000;
1820                 end.tv_sec--;
1821         }
1822         diff.tv_sec = end.tv_sec - start.tv_sec;
1823         diff.tv_usec = end.tv_usec - start.tv_usec;
1824         return diff;
1825 }
1826
1827 static void init_tdb(struct tdb_context *master_tdb,
1828                      const char *name, unsigned int hashsize)
1829 {
1830         TDB_DATA key, data;
1831         struct tdb_context *tdb;
1832
1833         tdb = tdb_open(name, hashsize, TDB_CLEAR_IF_FIRST|TDB_NOSYNC,
1834                        O_CREAT|O_TRUNC|O_RDWR, 0600);
1835         if (!tdb)
1836                 errx(1, "opening tdb %s", name);
1837
1838         for (key = tdb_firstkey(master_tdb);
1839              key.dptr;
1840              key = tdb_nextkey(master_tdb, key)) {
1841                 data = tdb_fetch(master_tdb, key);
1842                 if (tdb_store(tdb, key, data, TDB_INSERT) != 0)
1843                         errx(1, "Failed to store initial key");
1844         }
1845         tdb_close(tdb);
1846 }
1847
1848 int main(int argc, char *argv[])
1849 {
1850         struct timeval diff;
1851         unsigned int i, num_ops[argc], hashsize[argc], tdb_flags[argc], open_flags[argc];
1852         struct op *op[argc];
1853         int fds[2];
1854         struct tdb_context *master;
1855         unsigned int runs = 1;
1856
1857         if (argc < 3)
1858                 errx(1, "Usage: %s [--quiet] [-n <number>] <tdbfile> <tracefile>...", argv[0]);
1859
1860         if (streq(argv[1], "--quiet")) {
1861                 quiet = true;
1862                 argv++;
1863                 argc--;
1864         }
1865         if (streq(argv[1], "-n")) {
1866                 runs = atoi(argv[2]);
1867                 argv += 2;
1868                 argc -= 2;
1869         }
1870
1871         pipes = talloc_array(NULL, struct pipe, argc - 1);
1872         for (i = 0; i < argc - 2; i++) {
1873                 if (!quiet)
1874                         printf("Loading tracefile %s...", argv[2+i]);
1875                 fflush(stdout);
1876                 op[i] = load_tracefile(argv+2, i, &num_ops[i], &hashsize[i],
1877                                        &tdb_flags[i], &open_flags[i]);
1878                 if (pipe(pipes[i].fd) != 0)
1879                         err(1, "creating pipe");
1880                 /* Don't truncate, or clear if first: we do that. */
1881                 open_flags[i] &= ~(O_TRUNC);
1882                 tdb_flags[i] &= ~(TDB_CLEAR_IF_FIRST);
1883                 /* Open NOSYNC, to save time. */
1884                 tdb_flags[i] |= TDB_NOSYNC;
1885                 if (!quiet)
1886                         printf("done\n");
1887         }
1888
1889         /* Dependency may figure we need to create seed records. */
1890         master = tdb_open(NULL, 0, TDB_INTERNAL, O_RDWR, 0);
1891         if (!quiet) {
1892                 printf("Calculating inter-dependencies...");
1893                 fflush(stdout);
1894         }
1895         derive_dependencies(master, argv+2, op, num_ops, i);
1896         if (!quiet)
1897                 printf("done\n");
1898
1899         for (i = 0; i < runs; i++) {
1900                 init_tdb(master, argv[1], hashsize[0]);
1901
1902                 /* Don't fork for single arg case: simple debugging. */
1903                 if (argc == 3) {
1904                         struct timeval start, end;
1905                         struct tdb_context *tdb;
1906
1907                         tdb = tdb_open(argv[1], hashsize[0], tdb_flags[0],
1908                                        open_flags[0], 0600);
1909                         if (!quiet) {
1910                                 printf("Single threaded run...");
1911                                 fflush(stdout);
1912                         }
1913                         gettimeofday(&start, NULL);
1914
1915                         run_ops(tdb, pipes[0].fd[0], argv+2, op, 0, 1,
1916                                 num_ops[0], false);
1917                         gettimeofday(&end, NULL);
1918                         if (!quiet)
1919                                 printf("done\n");
1920                         tdb_close(tdb);
1921
1922                         check_deps(argv[2], op[0], num_ops[0]);
1923                         if (end.tv_usec < start.tv_usec) {
1924                                 end.tv_usec += 1000000;
1925                                 end.tv_sec--;
1926                         }
1927                         diff.tv_sec = end.tv_sec - start.tv_sec;
1928                         diff.tv_usec = end.tv_usec - start.tv_usec;
1929                         goto print_time;
1930                 }
1931
1932                 if (pipe(fds) != 0)
1933                         err(1, "creating pipe");
1934
1935 #if TRAVERSALS_TAKE_TRANSACTION_LOCK
1936                 if (pipe(pipes[argc-2].fd) != 0)
1937                         err(1, "creating pipe");
1938                 backoff_fd = pipes[argc-2].fd[1];
1939                 set_nonblock(pipes[argc-2].fd[1]);
1940                 set_nonblock(pipes[argc-2].fd[0]);
1941 #endif
1942
1943                 do {
1944                         diff = run_test(argv, num_ops, hashsize, tdb_flags,
1945                                         open_flags, op, fds);
1946                 } while (handle_backoff(op, pipes[argc-2].fd[0]));
1947
1948         print_time:
1949                 if (!quiet)
1950                         printf("Time replaying: ");
1951                 printf("%lu usec\n", diff.tv_sec * 1000000UL + diff.tv_usec);
1952         }
1953
1954         exit(0);
1955 }