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                 /* transaction/traverse start/chainlock */
 151                 unsigned int group_len;
 152         };
 153 };
 154
 155 static unsigned char hex_char(const char *filename, unsigned int line, char c)
 156 {
 157         c = toupper(c);
 158         if (c >= 'A' && c <= 'F')
 159                 return c - 'A' + 10;
 160         if (c >= '0' && c <= '9')
 161                 return c - '0';
 162         fail(filename, line, "invalid hex character '%c'", c);
 163 }
 164
 165 /* TDB data is <size>:<%02x>* */
 166 static TDB_DATA make_tdb_data(const void *ctx,
 167                               const char *filename, unsigned int line,
 168                               const char *word)
 169 {
 170         TDB_DATA data;
 171         unsigned int i;
 172         const char *p;
 173
 174         if (streq(word, "NULL"))
 175                 return tdb_null;
 176
 177         data.dsize = atoi(word);
 178         data.dptr = talloc_array(ctx, unsigned char, data.dsize);
 179         p = strchr(word, ':');
 180         if (!p)
 181                 fail(filename, line, "invalid tdb data '%s'", word);
 182         p++;
 183         for (i = 0; i < data.dsize; i++)
 184                 data.dptr[i] = hex_char(filename, line, p[i*2])*16
 185                         + hex_char(filename, line, p[i*2+1]);
 186
 187         return data;
 188 }
 189
 190 static void add_op(const char *filename, struct op **op, unsigned int i,
 191                    unsigned int serial, enum op_type type)
 192 {
 193         struct op *new;
 194         *op = talloc_realloc(NULL, *op, struct op, i+1);
 195         new = (*op) + i;
 196         new->op = type;
 197         new->serial = serial;
 198         new->ret = 0;
 199         new->group_start = 0;
 200 }
 201
 202 static void op_add_nothing(const char *filename,
 203                            struct op op[], unsigned int op_num, char *words[])
 204 {
 205         if (words[2])
 206                 fail(filename, op_num+1, "Expected no arguments");
 207         op[op_num].key = tdb_null;
 208 }
 209
 210 static void op_add_key(const char *filename,
 211                        struct op op[], unsigned int op_num, char *words[])
 212 {
 213         if (words[2] == NULL || words[3])
 214                 fail(filename, op_num+1, "Expected just a key");
 215
 216         op[op_num].key = make_tdb_data(op, filename, op_num+1, words[2]);
 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 /* We don't record the keys or data for a traverse, as we don't use them. */
 247 static void op_add_traverse(const char *filename,
 248                             struct op op[], unsigned int op_num, char *words[])
 249 {
 250         if (!words[2] || !words[3] || !words[4] || words[5]
 251             || !streq(words[3], "="))
 252                 fail(filename, op_num+1, "Expected <key> = <data>");
 253         op[op_num].key = tdb_null;
 254 }
 255
 256 /* Full traverse info is useful for debugging, but changing it to
 257  * "traversefn" without the data makes the traces *much* smaller! */
 258 static void op_add_traversefn(const char *filename,
 259                             struct op op[], unsigned int op_num, char *words[])
 260 {
 261         if (words[2])
 262                 fail(filename, op_num+1, "Expected no values");
 263         op[op_num].key = tdb_null;
 264 }
 265
 266 /* <serial> tdb_store <rec> <rec> <flag> = <ret> */
 267 static void op_add_store(const char *filename,
 268                          struct op op[], unsigned int op_num, char *words[])
 269 {
 270         if (!words[2] || !words[3] || !words[4] || !words[5] || !words[6]
 271             || words[7] || !streq(words[5], "="))
 272                 fail(filename, op_num+1, "Expect <key> <data> <flag> = <ret>");
 273
 274         op[op_num].flag = strtoul(words[4], NULL, 0);
 275         op[op_num].ret = atoi(words[6]);
 276         op[op_num].key = make_tdb_data(op, filename, op_num+1, words[2]);
 277         op[op_num].data = make_tdb_data(op, filename, op_num+1, words[3]);
 278         total_keys++;
 279 }
 280
 281 /* <serial> tdb_append <rec> <rec> = <rec> */
 282 static void op_add_append(const char *filename,
 283                           struct op op[], unsigned int op_num, char *words[])
 284 {
 285         if (!words[2] || !words[3] || !words[4] || !words[5] || words[6]
 286             || !streq(words[4], "="))
 287                 fail(filename, op_num+1, "Expect <key> <data> = <rec>");
 288
 289         op[op_num].key = make_tdb_data(op, filename, op_num+1, words[2]);
 290         op[op_num].data = make_tdb_data(op, filename, op_num+1, words[3]);
 291
 292         op[op_num].append.post
 293                 = make_tdb_data(op, filename, op_num+1, words[5]);
 294
 295         /* By subtraction, figure out what previous data was. */
 296         op[op_num].append.pre.dptr = op[op_num].append.post.dptr;
 297         op[op_num].append.pre.dsize
 298                 = op[op_num].append.post.dsize - op[op_num].data.dsize;
 299         total_keys++;
 300 }
 301
 302 /* <serial> tdb_get_seqnum = <ret> */
 303 static void op_add_seqnum(const char *filename,
 304                           struct op op[], unsigned int op_num, char *words[])
 305 {
 306         if (!words[2] || !words[3] || words[4] || !streq(words[2], "="))
 307                 fail(filename, op_num+1, "Expect = <ret>");
 308
 309         op[op_num].key = tdb_null;
 310         op[op_num].ret = atoi(words[3]);
 311 }
 312
 313 static void op_add_traverse_start(const char *filename,
 314                                   struct op op[],
 315                                   unsigned int op_num, char *words[])
 316 {
 317         if (words[2])
 318                 fail(filename, op_num+1, "Expect no arguments");
 319
 320         op[op_num].key = tdb_null;
 321         op[op_num].group_len = 0;
 322 }
 323
 324 static void op_add_transaction(const char *filename, struct op op[],
 325                                unsigned int op_num, char *words[])
 326 {
 327         if (words[2])
 328                 fail(filename, op_num+1, "Expect no arguments");
 329
 330         op[op_num].key = tdb_null;
 331         op[op_num].group_len = 0;
 332 }
 333
 334 static void op_add_chainlock(const char *filename,
 335                              struct op op[], unsigned int op_num, char *words[])
 336 {
 337         if (words[2] == NULL || words[3])
 338                 fail(filename, op_num+1, "Expected just a key");
 339
 340         /* A chainlock key isn't a key in the normal sense; it doesn't
 341          * have to be in the db at all.  Also, we don't want to hash this op. */
 342         op[op_num].data = make_tdb_data(op, filename, op_num+1, words[2]);
 343         op[op_num].key = tdb_null;
 344         op[op_num].group_len = 0;
 345 }
 346
 347 static void op_add_chainlock_ret(const char *filename,
 348                                  struct op op[], unsigned int op_num,
 349                                  char *words[])
 350 {
 351         if (!words[2] || !words[3] || !words[4] || words[5]
 352             || !streq(words[3], "="))
 353                 fail(filename, op_num+1, "Expected <key> = <ret>");
 354         op[op_num].ret = atoi(words[4]);
 355         op[op_num].data = make_tdb_data(op, filename, op_num+1, words[2]);
 356         op[op_num].key = tdb_null;
 357         op[op_num].group_len = 0;
 358         total_keys++;
 359 }
 360
 361 static int op_find_start(struct op op[], unsigned int op_num, enum op_type type)
 362 {
 363         unsigned int i;
 364
 365         for (i = op_num-1; i > 0; i--) {
 366                 if (op[i].op == type && !op[i].group_len)
 367                         return i;
 368         }
 369         return 0;
 370 }
 371
 372 static void op_analyze_transaction(const char *filename,
 373                                    struct op op[], unsigned int op_num,
 374                                    char *words[])
 375 {
 376         unsigned int start, i;
 377
 378         op[op_num].key = tdb_null;
 379
 380         if (words[2])
 381                 fail(filename, op_num+1, "Expect no arguments");
 382
 383         start = op_find_start(op, op_num, OP_TDB_TRANSACTION_START);
 384         if (!start)
 385                 fail(filename, op_num+1, "no transaction start found");
 386
 387         op[start].group_len = op_num - start;
 388
 389         /* This rolls in nested transactions.  I think that's right. */
 390         for (i = start; i <= op_num; i++)
 391                 op[i].group_start = start;
 392 }
 393
 394 /* We treat chainlocks a lot like transactions, even though that's overkill */
 395 static void op_analyze_chainlock(const char *filename,
 396                                  struct op op[], unsigned int op_num,
 397                                  char *words[])
 398 {
 399         unsigned int i, start;
 400
 401         if (words[2] == NULL || words[3])
 402                 fail(filename, op_num+1, "Expected just a key");
 403
 404         op[op_num].data = make_tdb_data(op, filename, op_num+1, words[2]);
 405         op[op_num].key = tdb_null;
 406         total_keys++;
 407
 408         start = op_find_start(op, op_num, OP_TDB_CHAINLOCK);
 409         if (!start)
 410                 start = op_find_start(op, op_num, OP_TDB_CHAINLOCK_READ);
 411         if (!start)
 412                 fail(filename, op_num+1, "no initial chainlock found");
 413
 414         /* FIXME: We'd have to do something clever to make this work
 415          * vs. deadlock. */
 416         if (!key_eq(op[start].data, op[op_num].data))
 417                 fail(filename, op_num+1, "nested chainlock calls?");
 418
 419         op[start].group_len = op_num - start;
 420         for (i = start; i <= op_num; i++)
 421                 op[i].group_start = start;
 422 }
 423
 424 static void op_analyze_traverse(const char *filename,
 425                                 struct op op[], unsigned int op_num,
 426                                 char *words[])
 427 {
 428         int i, start;
 429
 430         op[op_num].key = tdb_null;
 431
 432         /* = %u means traverse function terminated. */
 433         if (words[2]) {
 434                 if (!streq(words[2], "=") || !words[3] || words[4])
 435                         fail(filename, op_num+1, "expect = <num>");
 436                 op[op_num].ret = atoi(words[3]);
 437         } else
 438                 op[op_num].ret = 0;
 439
 440         start = op_find_start(op, op_num, OP_TDB_TRAVERSE_START);
 441         if (!start)
 442                 start = op_find_start(op, op_num, OP_TDB_TRAVERSE_READ_START);
 443         if (!start)
 444                 fail(filename, op_num+1, "no traversal start found");
 445
 446         op[start].group_len = op_num - start;
 447
 448         /* Don't roll in nested traverse/chainlock */
 449         for (i = start; i <= op_num; i++)
 450                 if (!op[i].group_start)
 451                         op[i].group_start = start;
 452 }
 453
 454 /* Keep -Wmissing-declarations happy: */
 455 const struct op_table *
 456 find_keyword (register const char *str, register unsigned int len);
 457
 458 #include "keywords.c"
 459
 460 struct depend {
 461         /* We can have more than one */
 462         struct list_node pre_list;
 463         struct list_node post_list;
 464         unsigned int needs_file;
 465         unsigned int needs_opnum;
 466         unsigned int satisfies_file;
 467         unsigned int satisfies_opnum;
 468 };
 469
 470 static void check_deps(const char *filename, struct op op[], unsigned int num)
 471 {
 472 #ifdef DEBUG_DEPS
 473         unsigned int i;
 474
 475         for (i = 1; i < num; i++)
 476                 if (!list_empty(&op[i].pre))
 477                         fail(filename, i+1, "Still has dependencies");
 478 #endif
 479 }
 480
 481 static void dump_pre(char *filename[], struct op *op[],
 482                      unsigned int file, unsigned int i)
 483 {
 484         struct depend *dep;
 485
 486         printf("%s:%u (%u) still waiting for:\n", filename[file], i+1,
 487                 op[file][i].serial);
 488         list_for_each(&op[file][i].pre, dep, pre_list)
 489                 printf("    %s:%u (%u)\n",
 490                        filename[dep->satisfies_file], dep->satisfies_opnum+1,
 491                        op[dep->satisfies_file][dep->satisfies_opnum].serial);
 492         check_deps(filename[file], op[file], i);
 493 }
 494
 495 /* We simply read/write pointers, since we all are children. */
 496 static bool do_pre(struct tdb_context *tdb,
 497                    char *filename[], struct op *op[],
 498                    unsigned int file, int pre_fd, unsigned int i,
 499                    bool backoff)
 500 {
 501         while (!list_empty(&op[file][i].pre)) {
 502                 struct depend *dep;
 503
 504 #if DEBUG_DEPS
 505                 printf("%s:%u:waiting for pre\n", filename[file], i+1);
 506                 fflush(stdout);
 507 #endif
 508                 if (backoff)
 509                         alarm(2);
 510                 else
 511                         alarm(10);
 512                 while (read(pre_fd, &dep, sizeof(dep)) != sizeof(dep)) {
 513                         if (errno == EINTR) {
 514                                 if (backoff) {
 515                                         warnx("%s:%u:avoiding deadlock",
 516                                               filename[file], i+1);
 517                                         return false;
 518                                 }
 519                                 dump_pre(filename, op, file, i);
 520                                 exit(1);
 521                         } else
 522                                 errx(1, "Reading from pipe");
 523                 }
 524                 alarm(0);
 525
 526 #if DEBUG_DEPS
 527                 printf("%s:%u:got pre %u from %s:%u\n", filename[file], i+1,
 528                        dep->needs_opnum+1, filename[dep->satisfies_file],
 529                        dep->satisfies_opnum+1);
 530                 fflush(stdout);
 531 #endif
 532                 /* This could be any op, not just this one. */
 533                 talloc_free(dep);
 534         }
 535         return true;
 536 }
 537
 538 static void do_post(char *filename[], struct op *op[],
 539                     unsigned int file, unsigned int i)
 540 {
 541         struct depend *dep;
 542
 543         list_for_each(&op[file][i].post, dep, post_list) {
 544 #if DEBUG_DEPS
 545                 printf("%s:%u:sending to file %s:%u\n", filename[file], i+1,
 546                        filename[dep->needs_file], dep->needs_opnum+1);
 547 #endif
 548                 if (write(pipes[dep->needs_file].fd[1], &dep, sizeof(dep))
 549                     != sizeof(dep))
 550                         err(1, "%s:%u failed to tell file %s",
 551                             filename[file], i+1, filename[dep->needs_file]);
 552         }
 553 }
 554
 555 static int get_len(TDB_DATA key, TDB_DATA data, void *private_data)
 556 {
 557         return data.dsize;
 558 }
 559
 560 static unsigned run_ops(struct tdb_context *tdb,
 561                         int pre_fd,
 562                         char *filename[],
 563                         struct op *op[],
 564                         unsigned int file,
 565                         unsigned int start, unsigned int stop,
 566                         bool backoff);
 567
 568 struct traverse_info {
 569         struct op **op;
 570         char **filename;
 571         unsigned file;
 572         int pre_fd;
 573         unsigned int start;
 574         unsigned int i;
 575 };
 576
 577 /* More complex.  Just do whatever's they did at the n'th entry. */
 578 static int nontrivial_traverse(struct tdb_context *tdb,
 579                                TDB_DATA key, TDB_DATA data,
 580                                void *_tinfo)
 581 {
 582         struct traverse_info *tinfo = _tinfo;
 583         unsigned int trav_len = tinfo->op[tinfo->file][tinfo->start].group_len;
 584         bool avoid_deadlock = false;
 585
 586         if (tinfo->i == tinfo->start + trav_len) {
 587                 /* This can happen if traverse expects to be empty. */
 588                 if (trav_len == 1)
 589                         return 1;
 590                 fail(tinfo->filename[tinfo->file], tinfo->start + 1,
 591                      "traverse did not terminate");
 592         }
 593
 594         if (tinfo->op[tinfo->file][tinfo->i].op != OP_TDB_TRAVERSE)
 595                 fail(tinfo->filename[tinfo->file], tinfo->start + 1,
 596                      "%s:%u:traverse terminated early");
 597
 598 #if TRAVERSALS_TAKE_TRANSACTION_LOCK
 599         avoid_deadlock = true;
 600 #endif
 601
 602         /* Run any normal ops. */
 603         tinfo->i = run_ops(tdb, tinfo->pre_fd, tinfo->filename, tinfo->op,
 604                            tinfo->file, tinfo->i+1, tinfo->start + trav_len,
 605                            avoid_deadlock);
 606
 607         /* We backed off, or we hit OP_TDB_TRAVERSE_END. */
 608         if (tinfo->op[tinfo->file][tinfo->i].op != OP_TDB_TRAVERSE)
 609                 return 1;
 610
 611         return 0;
 612 }
 613
 614 static unsigned op_traverse(struct tdb_context *tdb,
 615                             int pre_fd,
 616                             char *filename[],
 617                             unsigned int file,
 618                             int (*traversefn)(struct tdb_context *,
 619                                               tdb_traverse_func, void *),
 620                             struct op *op[],
 621                             unsigned int start)
 622 {
 623         struct traverse_info tinfo = { op, filename, file, pre_fd,
 624                                        start, start+1 };
 625
 626         traversefn(tdb, nontrivial_traverse, &tinfo);
 627
 628         /* Traversing in wrong order can have strange effects: eg. if
 629          * original traverse went A (delete A), B, we might do B
 630          * (delete A).  So if we have ops left over, we do it now. */
 631         while (tinfo.i != start + op[file][start].group_len) {
 632                 if (op[file][tinfo.i].op == OP_TDB_TRAVERSE)
 633                         tinfo.i++;
 634                 else
 635                         tinfo.i = run_ops(tdb, pre_fd, filename, op, file,
 636                                           tinfo.i,
 637                                           start + op[file][start].group_len,
 638                                           false);
 639         }
 640
 641         return tinfo.i;
 642 }
 643
 644 static void break_out(int sig)
 645 {
 646 }
 647
 648 static __attribute__((noinline))
 649 unsigned run_ops(struct tdb_context *tdb,
 650                  int pre_fd,
 651                  char *filename[],
 652                  struct op *op[],
 653                  unsigned int file,
 654                  unsigned int start, unsigned int stop,
 655                  bool backoff)
 656 {
 657         unsigned int i;
 658         struct sigaction sa;
 659
 660         sa.sa_handler = break_out;
 661         sa.sa_flags = 0;
 662
 663         sigaction(SIGALRM, &sa, NULL);
 664         for (i = start; i < stop; i++) {
 665                 if (!do_pre(tdb, filename, op, file, pre_fd, i, backoff))
 666                         return i;
 667
 668                 switch (op[file][i].op) {
 669                 case OP_TDB_LOCKALL:
 670                         try(tdb_lockall(tdb), op[file][i].ret);
 671                         break;
 672                 case OP_TDB_LOCKALL_MARK:
 673                         try(tdb_lockall_mark(tdb), op[file][i].ret);
 674                         break;
 675                 case OP_TDB_LOCKALL_UNMARK:
 676                         try(tdb_lockall_unmark(tdb), op[file][i].ret);
 677                         break;
 678                 case OP_TDB_LOCKALL_NONBLOCK:
 679                         unreliable(tdb_lockall_nonblock(tdb), op[file][i].ret,
 680                                    tdb_lockall(tdb), tdb_unlockall(tdb));
 681                         break;
 682                 case OP_TDB_UNLOCKALL:
 683                         try(tdb_unlockall(tdb), op[file][i].ret);
 684                         break;
 685                 case OP_TDB_LOCKALL_READ:
 686                         try(tdb_lockall_read(tdb), op[file][i].ret);
 687                         break;
 688                 case OP_TDB_LOCKALL_READ_NONBLOCK:
 689                         unreliable(tdb_lockall_read_nonblock(tdb),
 690                                    op[file][i].ret,
 691                                    tdb_lockall_read(tdb),
 692                                    tdb_unlockall_read(tdb));
 693                         break;
 694                 case OP_TDB_UNLOCKALL_READ:
 695                         try(tdb_unlockall_read(tdb), op[file][i].ret);
 696                         break;
 697                 case OP_TDB_CHAINLOCK:
 698                         try(tdb_chainlock(tdb, op[file][i].key),
 699                             op[file][i].ret);
 700                         break;
 701                 case OP_TDB_CHAINLOCK_NONBLOCK:
 702                         unreliable(tdb_chainlock_nonblock(tdb, op[file][i].key),
 703                                    op[file][i].ret,
 704                                    tdb_chainlock(tdb, op[file][i].key),
 705                                    tdb_chainunlock(tdb, op[file][i].key));
 706                         break;
 707                 case OP_TDB_CHAINLOCK_MARK:
 708                         try(tdb_chainlock_mark(tdb, op[file][i].key),
 709                             op[file][i].ret);
 710                         break;
 711                 case OP_TDB_CHAINLOCK_UNMARK:
 712                         try(tdb_chainlock_unmark(tdb, op[file][i].key),
 713                             op[file][i].ret);
 714                         break;
 715                 case OP_TDB_CHAINUNLOCK:
 716                         try(tdb_chainunlock(tdb, op[file][i].key),
 717                             op[file][i].ret);
 718                         break;
 719                 case OP_TDB_CHAINLOCK_READ:
 720                         try(tdb_chainlock_read(tdb, op[file][i].key),
 721                             op[file][i].ret);
 722                         break;
 723                 case OP_TDB_CHAINUNLOCK_READ:
 724                         try(tdb_chainunlock_read(tdb, op[file][i].key),
 725                             op[file][i].ret);
 726                         break;
 727                 case OP_TDB_PARSE_RECORD:
 728                         try(tdb_parse_record(tdb, op[file][i].key, get_len,
 729                                              NULL),
 730                             op[file][i].ret);
 731                         break;
 732                 case OP_TDB_EXISTS:
 733                         try(tdb_exists(tdb, op[file][i].key), op[file][i].ret);
 734                         break;
 735                 case OP_TDB_STORE:
 736                         try(tdb_store(tdb, op[file][i].key, op[file][i].data,
 737                                       op[file][i].flag),
 738                             op[file][i].ret);
 739                         break;
 740                 case OP_TDB_APPEND:
 741                         try(tdb_append(tdb, op[file][i].key, op[file][i].data),
 742                             op[file][i].ret);
 743                         break;
 744                 case OP_TDB_GET_SEQNUM:
 745                         try(tdb_get_seqnum(tdb), op[file][i].ret);
 746                         break;
 747                 case OP_TDB_WIPE_ALL:
 748                         try(tdb_wipe_all(tdb), op[file][i].ret);
 749                         break;
 750                 case OP_TDB_TRANSACTION_START:
 751                         try(tdb_transaction_start(tdb), op[file][i].ret);
 752                         break;
 753                 case OP_TDB_TRANSACTION_CANCEL:
 754                         try(tdb_transaction_cancel(tdb), op[file][i].ret);
 755                         break;
 756                 case OP_TDB_TRANSACTION_COMMIT:
 757                         try(tdb_transaction_commit(tdb), op[file][i].ret);
 758                         break;
 759                 case OP_TDB_TRAVERSE_READ_START:
 760                         i = op_traverse(tdb, pre_fd, filename, file,
 761                                         tdb_traverse_read, op, i);
 762                         break;
 763                 case OP_TDB_TRAVERSE_START:
 764                         i = op_traverse(tdb, pre_fd, filename, file,
 765                                         tdb_traverse, op, i);
 766                         break;
 767                 case OP_TDB_TRAVERSE:
 768                         /* Terminate: we're in a traverse, and we've
 769                          * done our ops. */
 770                         return i;
 771                 case OP_TDB_TRAVERSE_END:
 772                         fail(filename[file], i+1, "unexpected end traverse");
 773                 /* FIXME: These must be treated like traverse. */
 774                 case OP_TDB_FIRSTKEY:
 775                         if (!key_eq(tdb_firstkey(tdb), op[file][i].data))
 776                                 fail(filename[file], i+1, "bad firstkey");
 777                         break;
 778                 case OP_TDB_NEXTKEY:
 779                         if (!key_eq(tdb_nextkey(tdb, op[file][i].key),
 780                                     op[file][i].data))
 781                                 fail(filename[file], i+1, "bad nextkey");
 782                         break;
 783                 case OP_TDB_FETCH: {
 784                         TDB_DATA f = tdb_fetch(tdb, op[file][i].key);
 785                         if (!key_eq(f, op[file][i].data))
 786                                 fail(filename[file], i+1, "bad fetch %u",
 787                                      f.dsize);
 788                         break;
 789                 }
 790                 case OP_TDB_DELETE:
 791                         try(tdb_delete(tdb, op[file][i].key), op[file][i].ret);
 792                         break;
 793                 }
 794                 do_post(filename, op, file, i);
 795         }
 796         return i;
 797 }
 798
 799 /* tdbtorture, in particular, can do a tdb_close with a transaction in
 800  * progress. */
 801 static struct op *maybe_cancel_transaction(const char *filename,
 802                                            struct op *op, unsigned int *num)
 803 {
 804         unsigned int start = op_find_start(op, *num, OP_TDB_TRANSACTION_START);
 805
 806         if (start) {
 807                 char *words[] = { "<unknown>", "tdb_close", NULL };
 808                 add_op(filename, &op, *num, op[start].serial,
 809                        OP_TDB_TRANSACTION_CANCEL);
 810                 op_analyze_transaction(filename, op, *num, words);
 811                 (*num)++;
 812         }
 813         return op;
 814 }
 815
 816 static struct op *load_tracefile(const char *filename, unsigned int *num,
 817                                  unsigned int *hashsize,
 818                                  unsigned int *tdb_flags,
 819                                  unsigned int *open_flags)
 820 {
 821         unsigned int i;
 822         struct op *op = talloc_array(NULL, struct op, 1);
 823         char **words;
 824         char **lines;
 825         char *file;
 826
 827         file = grab_file(NULL, filename, NULL);
 828         if (!file)
 829                 err(1, "Reading %s", filename);
 830
 831         lines = strsplit(file, file, "\n", NULL);
 832         if (!lines[0])
 833                 errx(1, "%s is empty", filename);
 834
 835         words = strsplit(lines, lines[0], " ", NULL);
 836         if (!streq(words[1], "tdb_open"))
 837                 fail(filename, 1, "does not start with tdb_open");
 838
 839         *hashsize = atoi(words[2]);
 840         *tdb_flags = strtoul(words[3], NULL, 0);
 841         *open_flags = strtoul(words[4], NULL, 0);
 842
 843         for (i = 1; lines[i]; i++) {
 844                 const struct op_table *opt;
 845
 846                 words = strsplit(lines, lines[i], " ", NULL);
 847                 if (!words[0] || !words[1])
 848                         fail(filename, i+1, "Expected serial number and op");
 849
 850                 opt = find_keyword(words[1], strlen(words[1]));
 851                 if (!opt) {
 852                         if (streq(words[1], "tdb_close")) {
 853                                 if (lines[i+1])
 854                                         fail(filename, i+2,
 855                                              "lines after tdb_close");
 856                                 *num = i;
 857                                 talloc_free(lines);
 858                                 return maybe_cancel_transaction(filename,
 859                                                                 op, num);
 860                         }
 861                         fail(filename, i+1, "Unknown operation '%s'", words[1]);
 862                 }
 863
 864                 add_op(filename, &op, i, atoi(words[0]), opt->type);
 865                 opt->enhance_op(filename, op, i, words);
 866         }
 867
 868         fprintf(stderr, "%s:%u:last operation is not tdb_close: incomplete?",
 869               filename, i);
 870         talloc_free(lines);
 871         *num = i - 1;
 872         return maybe_cancel_transaction(filename, op, num);
 873 }
 874
 875 /* We remember all the keys we've ever seen, and who has them. */
 876 struct key_user {
 877         unsigned int file;
 878         unsigned int op_num;
 879 };
 880
 881 struct keyinfo {
 882         TDB_DATA key;
 883         unsigned int num_users;
 884         struct key_user *user;
 885 };
 886
 887 static const TDB_DATA must_not_exist;
 888 static const TDB_DATA must_exist;
 889 static const TDB_DATA not_exists_or_empty;
 890
 891 /* NULL means doesn't care if it exists or not, &must_exist means
 892  * it must exist but we don't care what, &must_not_exist means it must
 893  * not exist, otherwise the data it needs. */
 894 static const TDB_DATA *needs(const struct op *op)
 895 {
 896         switch (op->op) {
 897         /* FIXME: Pull forward deps, since we can deadlock */
 898         case OP_TDB_CHAINLOCK:
 899         case OP_TDB_CHAINLOCK_NONBLOCK:
 900         case OP_TDB_CHAINLOCK_MARK:
 901         case OP_TDB_CHAINLOCK_UNMARK:
 902         case OP_TDB_CHAINUNLOCK:
 903         case OP_TDB_CHAINLOCK_READ:
 904         case OP_TDB_CHAINUNLOCK_READ:
 905                 return NULL;
 906
 907         case OP_TDB_APPEND:
 908                 if (op->append.pre.dsize == 0)
 909                         return &not_exists_or_empty;
 910                 return &op->append.pre;
 911
 912         case OP_TDB_STORE:
 913                 if (op->flag == TDB_INSERT) {
 914                         if (op->ret < 0)
 915                                 return &must_exist;
 916                         else
 917                                 return &must_not_exist;
 918                 } else if (op->flag == TDB_MODIFY) {
 919                         if (op->ret < 0)
 920                                 return &must_not_exist;
 921                         else
 922                                 return &must_exist;
 923                 }
 924                 /* No flags?  Don't care */
 925                 return NULL;
 926
 927         case OP_TDB_EXISTS:
 928                 if (op->ret == 1)
 929                         return &must_exist;
 930                 else
 931                         return &must_not_exist;
 932
 933         case OP_TDB_PARSE_RECORD:
 934                 if (op->ret < 0)
 935                         return &must_not_exist;
 936                 return &must_exist;
 937
 938         /* FIXME: handle these. */
 939         case OP_TDB_WIPE_ALL:
 940         case OP_TDB_FIRSTKEY:
 941         case OP_TDB_NEXTKEY:
 942         case OP_TDB_GET_SEQNUM:
 943         case OP_TDB_TRAVERSE:
 944         case OP_TDB_TRANSACTION_COMMIT:
 945         case OP_TDB_TRANSACTION_CANCEL:
 946         case OP_TDB_TRANSACTION_START:
 947                 return NULL;
 948
 949         case OP_TDB_FETCH:
 950                 if (!op->data.dptr)
 951                         return &must_not_exist;
 952                 return &op->data;
 953
 954         case OP_TDB_DELETE:
 955                 if (op->ret < 0)
 956                         return &must_not_exist;
 957                 return &must_exist;
 958
 959         default:
 960                 errx(1, "Unexpected op %i", op->op);
 961         }
 962
 963 }
 964
 965 static bool starts_transaction(const struct op *op)
 966 {
 967         return op->op == OP_TDB_TRANSACTION_START;
 968 }
 969
 970 static bool in_transaction(const struct op op[], unsigned int i)
 971 {
 972         return op[i].group_start && starts_transaction(&op[op[i].group_start]);
 973 }
 974
 975 static bool successful_transaction(const struct op *op)
 976 {
 977         return starts_transaction(op)
 978                 && op[op->group_len].op == OP_TDB_TRANSACTION_COMMIT;
 979 }
 980
 981 static bool starts_traverse(const struct op *op)
 982 {
 983         return op->op == OP_TDB_TRAVERSE_START
 984                 || op->op == OP_TDB_TRAVERSE_READ_START;
 985 }
 986
 987 static bool in_traverse(const struct op op[], unsigned int i)
 988 {
 989         return op[i].group_start && starts_traverse(&op[op[i].group_start]);
 990 }
 991
 992 static bool starts_chainlock(const struct op *op)
 993 {
 994         return op->op == OP_TDB_CHAINLOCK_READ || op->op == OP_TDB_CHAINLOCK;
 995 }
 996
 997 static bool in_chainlock(const struct op op[], unsigned int i)
 998 {
 999         return op[i].group_start && starts_chainlock(&op[op[i].group_start]);
1000 }
1001
1002 /* What's the data after this op?  pre if nothing changed. */
1003 static const TDB_DATA *gives(const TDB_DATA *key, const TDB_DATA *pre,
1004                              const struct op *op)
1005 {
1006         if (starts_transaction(op) || starts_chainlock(op)) {
1007                 unsigned int i;
1008
1009                 /* Cancelled transactions don't change anything. */
1010                 if (op[op->group_len].op == OP_TDB_TRANSACTION_CANCEL)
1011                         return pre;
1012                 assert(op[op->group_len].op == OP_TDB_TRANSACTION_COMMIT
1013                        || op[op->group_len].op == OP_TDB_CHAINUNLOCK_READ
1014                        || op[op->group_len].op == OP_TDB_CHAINUNLOCK);
1015
1016                 for (i = 1; i < op->group_len; i++) {
1017                         /* This skips nested transactions, too */
1018                         if (key_eq(op[i].key, *key))
1019                                 pre = gives(key, pre, &op[i]);
1020                 }
1021                 return pre;
1022         }
1023
1024         /* Failed ops don't change state of db. */
1025         if (op->ret < 0)
1026                 return pre;
1027
1028         if (op->op == OP_TDB_DELETE || op->op == OP_TDB_WIPE_ALL)
1029                 return &tdb_null;
1030
1031         if (op->op == OP_TDB_APPEND)
1032                 return &op->append.post;
1033
1034         if (op->op == OP_TDB_STORE)
1035                 return &op->data;
1036
1037         return pre;
1038 }
1039
1040 static struct keyinfo *hash_ops(struct op *op[], unsigned int num_ops[],
1041                                 unsigned int num)
1042 {
1043         unsigned int i, j, h;
1044         struct keyinfo *hash;
1045
1046         hash = talloc_zero_array(op[0], struct keyinfo, total_keys*2);
1047         for (i = 0; i < num; i++) {
1048                 for (j = 1; j < num_ops[i]; j++) {
1049                         /* We can't do this on allocation, due to realloc. */
1050                         list_head_init(&op[i][j].post);
1051                         list_head_init(&op[i][j].pre);
1052
1053                         if (!op[i][j].key.dptr)
1054                                 continue;
1055
1056                         h = hash_key(&op[i][j].key) % (total_keys * 2);
1057                         while (!key_eq(hash[h].key, op[i][j].key)) {
1058                                 if (!hash[h].key.dptr) {
1059                                         hash[h].key = op[i][j].key;
1060                                         break;
1061                                 }
1062                                 h = (h + 1) % (total_keys * 2);
1063                         }
1064                         /* Might as well save some memory if we can. */
1065                         if (op[i][j].key.dptr != hash[h].key.dptr) {
1066                                 talloc_free(op[i][j].key.dptr);
1067                                 op[i][j].key.dptr = hash[h].key.dptr;
1068                         }
1069                         hash[h].user = talloc_realloc(hash, hash[h].user,
1070                                                      struct key_user,
1071                                                      hash[h].num_users+1);
1072
1073                         /* If it's in a transaction, it's the transaction which
1074                          * matters from an analysis POV. */
1075                         if (in_transaction(op[i], j)
1076                             || in_chainlock(op[i], j)) {
1077                                 unsigned start = op[i][j].group_start;
1078
1079                                 /* Don't include twice. */
1080                                 if (hash[h].num_users
1081                                     && hash[h].user[hash[h].num_users-1].file
1082                                         == i
1083                                     && hash[h].user[hash[h].num_users-1].op_num
1084                                         == start)
1085                                         continue;
1086
1087                                 hash[h].user[hash[h].num_users].op_num = start;
1088                         } else
1089                                 hash[h].user[hash[h].num_users].op_num = j;
1090                         hash[h].user[hash[h].num_users].file = i;
1091                         hash[h].num_users++;
1092                 }
1093         }
1094
1095         return hash;
1096 }
1097
1098 static bool satisfies(const TDB_DATA *key, const TDB_DATA *data,
1099                       const struct op *op)
1100 {
1101         const TDB_DATA *need = NULL;
1102
1103         if (starts_transaction(op) || starts_chainlock(op)) {
1104                 unsigned int i;
1105
1106                 /* Look through for an op in this transaction which
1107                  * needs this key. */
1108                 for (i = 1; i < op->group_len; i++) {
1109                         if (key_eq(op[i].key, *key)) {
1110                                 need = needs(&op[i]);
1111                                 /* tdb_exists() is special: there might be
1112                                  * something in the transaction with more
1113                                  * specific requirements.  Other ops don't have
1114                                  * specific requirements (eg. store or delete),
1115                                  * but they change the value so we can't get
1116                                  * more information from future ops. */
1117                                 if (op[i].op != OP_TDB_EXISTS)
1118                                         break;
1119                         }
1120                 }
1121         } else
1122                 need = needs(op);
1123
1124         /* Don't need anything?  Cool. */
1125         if (!need)
1126                 return true;
1127
1128         /* This should be tdb_null or a real value. */
1129         assert(data != &must_exist);
1130         assert(data != &must_not_exist);
1131         assert(data != &not_exists_or_empty);
1132
1133         /* Must not exist?  data must not exist. */
1134         if (need == &must_not_exist)
1135                 return data == &tdb_null;
1136
1137         /* Must exist? */
1138         if (need == &must_exist)
1139                 return data != &tdb_null;
1140
1141         /* Either noexist or empty. */
1142         if (need == &not_exists_or_empty)
1143                 return data->dsize == 0;
1144
1145         /* Needs something specific. */
1146         return key_eq(*data, *need);
1147 }
1148
1149 static void move_to_front(struct key_user res[], unsigned off, unsigned elem)
1150 {
1151         if (elem != off) {
1152                 struct key_user tmp = res[elem];
1153                 memmove(res + off + 1, res + off, (elem - off)*sizeof(res[0]));
1154                 res[off] = tmp;
1155         }
1156 }
1157
1158 static void restore_to_pos(struct key_user res[], unsigned off, unsigned elem)
1159 {
1160         if (elem != off) {
1161                 struct key_user tmp = res[off];
1162                 memmove(res + off, res + off + 1, (elem - off)*sizeof(res[0]));
1163                 res[elem] = tmp;
1164         }
1165 }
1166
1167 static bool sort_deps(char *filename[], struct op *op[],
1168                       struct key_user res[],
1169                       unsigned off, unsigned num,
1170                       const TDB_DATA *key, const TDB_DATA *data,
1171                       unsigned num_files, unsigned fuzz)
1172 {
1173         unsigned int i, files_done;
1174         struct op *this_op;
1175         bool done[num_files];
1176
1177         /* None left?  We're sorted. */
1178         if (off == num)
1179                 return true;
1180
1181         /* Does this make serial numbers go backwards?  Allow a little fuzz. */
1182         if (off > 0) {
1183                 int serial1 = op[res[off-1].file][res[off-1].op_num].serial;
1184                 int serial2 = op[res[off].file][res[off].op_num].serial;
1185
1186                 if (serial1 - serial2 > (int)fuzz) {
1187 #if DEBUG_DEPS
1188                         printf("Serial jump too far (%u -> %u)\n",
1189                                serial1, serial2);
1190 #endif
1191                         return false;
1192                 }
1193         }
1194
1195         memset(done, 0, sizeof(done));
1196
1197         /* Since ops within a trace file are ordered, we just need to figure
1198          * out which file to try next.  Since we don't take into account
1199          * inter-key relationships (which exist by virtue of trace file order),
1200          * we minimize the chance of harm by trying to keep in serial order. */
1201         for (files_done = 0, i = off; i < num && files_done < num_files; i++) {
1202                 if (done[res[i].file])
1203                         continue;
1204
1205                 this_op = &op[res[i].file][res[i].op_num];
1206
1207                 /* Is what we have good enough for this op? */
1208                 if (satisfies(key, data, this_op)) {
1209                         move_to_front(res, off, i);
1210                         if (sort_deps(filename, op, res, off+1, num,
1211                                       key, gives(key, data, this_op),
1212                                       num_files, fuzz))
1213                                 return true;
1214                         restore_to_pos(res, off, i);
1215                 }
1216                 done[res[i].file] = true;
1217                 files_done++;
1218         }
1219
1220         /* No combination worked. */
1221         return false;
1222 }
1223
1224 static void check_dep_sorting(struct key_user user[], unsigned num_users,
1225                               unsigned num_files)
1226 {
1227 #if DEBUG_DEPS
1228         unsigned int i;
1229         unsigned minima[num_files];
1230
1231         memset(minima, 0, sizeof(minima));
1232         for (i = 0; i < num_users; i++) {
1233                 assert(minima[user[i].file] < user[i].op_num);
1234                 minima[user[i].file] = user[i].op_num;
1235         }
1236 #endif
1237 }
1238
1239 /* All these ops happen on the same key.  Which comes first?
1240  *
1241  * This can happen both because read ops or failed write ops don't
1242  * change serial number, and also due to race since we access the
1243  * number unlocked (the race can cause less detectable ordering problems,
1244  * in which case we'll deadlock and report: fix manually in that case).
1245  */
1246 static void figure_deps(char *filename[], struct op *op[],
1247                         const TDB_DATA *key, struct key_user user[],
1248                         unsigned num_users, unsigned num_files)
1249 {
1250         /* We assume database starts empty. */
1251         const struct TDB_DATA *data = &tdb_null;
1252         unsigned int fuzz;
1253
1254         /* We prefer to keep strict serial order if possible: it's the
1255          * most likely.  We get more lax if that fails. */
1256         for (fuzz = 0; fuzz < 100; fuzz = (fuzz + 1)*2) {
1257                 if (sort_deps(filename, op, user, 0, num_users, key, data,
1258                               num_files, fuzz))
1259                         break;
1260         }
1261
1262         if (fuzz >= 100)
1263                 fail(filename[user[0].file], user[0].op_num+1,
1264                      "Could not resolve inter-dependencies");
1265
1266         check_dep_sorting(user, num_users, num_files);
1267 }
1268
1269 static void sort_ops(struct keyinfo hash[], char *filename[], struct op *op[],
1270                      unsigned int num)
1271 {
1272         unsigned int h;
1273
1274         /* Gcc nexted function extension.  How cool is this? */
1275         int compare_serial(const void *_a, const void *_b)
1276         {
1277                 const struct key_user *a = _a, *b = _b;
1278
1279                 /* First, maintain order within any trace file. */
1280                 if (a->file == b->file)
1281                         return a->op_num - b->op_num;
1282
1283                 /* Otherwise, arrange by serial order. */
1284                 if (op[a->file][a->op_num].serial !=
1285                     op[b->file][b->op_num].serial)
1286                         return op[a->file][a->op_num].serial
1287                                 - op[b->file][b->op_num].serial;
1288
1289                 /* Cancelled transactions are assumed to happen first. */
1290                 if (starts_transaction(&op[a->file][a->op_num])
1291                     && !successful_transaction(&op[a->file][a->op_num]))
1292                         return -1;
1293                 if (starts_transaction(&op[b->file][b->op_num])
1294                     && !successful_transaction(&op[b->file][b->op_num]))
1295                         return 1;
1296
1297                 /* No idea. */
1298                 return 0;
1299         }
1300
1301         /* Now sort into serial order. */
1302         for (h = 0; h < total_keys * 2; h++) {
1303                 struct key_user *user = hash[h].user;
1304
1305                 qsort(user, hash[h].num_users, sizeof(user[0]), compare_serial);
1306                 figure_deps(filename, op, &hash[h].key, user, hash[h].num_users,
1307                             num);
1308         }
1309 }
1310
1311 static int destroy_depend(struct depend *dep)
1312 {
1313         list_del(&dep->pre_list);
1314         list_del(&dep->post_list);
1315         return 0;
1316 }
1317
1318 static void add_dependency(void *ctx,
1319                            struct op *op[],
1320                            char *filename[],
1321                            unsigned int needs_file,
1322                            unsigned int needs_opnum,
1323                            unsigned int satisfies_file,
1324                            unsigned int satisfies_opnum)
1325 {
1326         struct depend *dep;
1327
1328         /* We don't depend on ourselves. */
1329         if (needs_file == satisfies_file) {
1330                 assert(satisfies_opnum < needs_opnum);
1331                 return;
1332         }
1333
1334 #if DEBUG_DEPS
1335         printf("%s:%u: depends on %s:%u\n",
1336                filename[needs_file], needs_opnum+1,
1337                filename[satisfies_file], satisfies_opnum+1);
1338 #endif
1339
1340 #if TRAVERSALS_TAKE_TRANSACTION_LOCK
1341         /* If something in a traverse depends on something in another
1342          * traverse/transaction, it creates a dependency between the
1343          * two groups. */
1344         if ((in_traverse(op[satisfies_file], satisfies_opnum)
1345              && (starts_transaction(&op[needs_file][needs_opnum])
1346                  || starts_traverse(&op[needs_file][needs_opnum])))
1347             || (in_traverse(op[needs_file], needs_opnum)
1348                 && (starts_transaction(&op[satisfies_file][satisfies_opnum])
1349                     || starts_traverse(&op[satisfies_file][satisfies_opnum])))){
1350                 unsigned int sat;
1351
1352                 /* We are satisfied by end of group. */
1353                 sat = op[satisfies_file][satisfies_opnum].group_start;
1354                 satisfies_opnum = sat + op[satisfies_file][sat].group_len;
1355                 /* And we need that done by start of our group. */
1356                 needs_opnum = op[needs_file][needs_opnum].group_start;
1357         }
1358
1359         /* There is also this case:
1360          *  <traverse> <read foo> ...
1361          *  <transaction> ... </transaction> <create foo>
1362          * Where if we start the traverse then wait, we could block
1363          * the transaction and deadlock.
1364          *
1365          * We try to address this by ensuring that where seqnum indicates it's
1366          * possible, we wait for <create foo> before *starting* traverse.
1367          */
1368         else if (in_traverse(op[needs_file], needs_opnum)) {
1369                 struct op *need = &op[needs_file][needs_opnum];
1370                 if (op[needs_file][need->group_start].serial >
1371                     op[satisfies_file][satisfies_opnum].serial) {
1372                         needs_opnum = need->group_start;
1373                 }
1374         }
1375 #endif
1376
1377         /* If you depend on a transaction or chainlock, you actually
1378          * depend on it ending. */
1379         if (starts_transaction(&op[satisfies_file][satisfies_opnum])
1380             || starts_chainlock(&op[satisfies_file][satisfies_opnum])) {
1381                 satisfies_opnum
1382                         += op[satisfies_file][satisfies_opnum].group_len;
1383 #if DEBUG_DEPS
1384                 printf("-> Actually end of transaction %s:%u\n",
1385                        filename[satisfies_file], satisfies_opnum+1);
1386 #endif
1387         } else
1388                 /* We should never create a dependency from middle of
1389                  * a transaction. */
1390                 assert(!in_transaction(op[satisfies_file], satisfies_opnum)
1391                        || op[satisfies_file][satisfies_opnum].op
1392                        == OP_TDB_TRANSACTION_COMMIT
1393                        || op[satisfies_file][satisfies_opnum].op
1394                        == OP_TDB_TRANSACTION_CANCEL);
1395
1396         assert(op[needs_file][needs_opnum].op != OP_TDB_TRAVERSE);
1397         assert(op[satisfies_file][satisfies_opnum].op != OP_TDB_TRAVERSE);
1398
1399         dep = talloc(ctx, struct depend);
1400         dep->needs_file = needs_file;
1401         dep->needs_opnum = needs_opnum;
1402         dep->satisfies_file = satisfies_file;
1403         dep->satisfies_opnum = satisfies_opnum;
1404         list_add(&op[satisfies_file][satisfies_opnum].post, &dep->post_list);
1405         list_add(&op[needs_file][needs_opnum].pre, &dep->pre_list);
1406         talloc_set_destructor(dep, destroy_depend);
1407 }
1408
1409 static bool changes_db(const TDB_DATA *key, const struct op *op)
1410 {
1411         return gives(key, NULL, op) != NULL;
1412 }
1413
1414 static void depend_on_previous(struct op *op[],
1415                                char *filename[],
1416                                unsigned int num,
1417                                struct key_user user[],
1418                                unsigned int i,
1419                                int prev)
1420 {
1421         bool deps[num];
1422         int j;
1423
1424         if (i == 0)
1425                 return;
1426
1427         if (prev == i - 1) {
1428                 /* Just depend on previous. */
1429                 add_dependency(NULL, op, filename,
1430                                user[i].file, user[i].op_num,
1431                                user[prev].file, user[prev].op_num);
1432                 return;
1433         }
1434
1435         /* We have to wait for the readers.  Find last one in *each* file. */
1436         memset(deps, 0, sizeof(deps));
1437         deps[user[i].file] = true;
1438         for (j = i - 1; j > prev; j--) {
1439                 if (!deps[user[j].file]) {
1440                         add_dependency(NULL, op, filename,
1441                                        user[i].file, user[i].op_num,
1442                                        user[j].file, user[j].op_num);
1443                         deps[user[j].file] = true;
1444                 }
1445         }
1446 }
1447
1448 /* This is simple, but not complete.  We don't take into account
1449  * indirect dependencies. */
1450 static void optimize_dependencies(struct op *op[], unsigned int num_ops[],
1451                                   unsigned int num)
1452 {
1453         unsigned int i, j;
1454
1455         /* There can only be one real dependency on each file */
1456         for (i = 0; i < num; i++) {
1457                 for (j = 1; j < num_ops[i]; j++) {
1458                         struct depend *dep, *next;
1459                         struct depend *prev[num];
1460
1461                         memset(prev, 0, sizeof(prev));
1462
1463                         list_for_each_safe(&op[i][j].pre, dep, next, pre_list) {
1464                                 if (!prev[dep->satisfies_file]) {
1465                                         prev[dep->satisfies_file] = dep;
1466                                         continue;
1467                                 }
1468                                 if (prev[dep->satisfies_file]->satisfies_opnum
1469                                     < dep->satisfies_opnum) {
1470                                         talloc_free(prev[dep->satisfies_file]);
1471                                         prev[dep->satisfies_file] = dep;
1472                                 } else
1473                                         talloc_free(dep);
1474                         }
1475                 }
1476         }
1477
1478         for (i = 0; i < num; i++) {
1479                 int deps[num];
1480
1481                 for (j = 0; j < num; j++)
1482                         deps[j] = -1;
1483
1484                 for (j = 1; j < num_ops[i]; j++) {
1485                         struct depend *dep, *next;
1486
1487                         list_for_each_safe(&op[i][j].pre, dep, next, pre_list) {
1488                                 if (deps[dep->satisfies_file]
1489                                     >= (int)dep->satisfies_opnum)
1490                                         talloc_free(dep);
1491                                 else
1492                                         deps[dep->satisfies_file]
1493                                                 = dep->satisfies_opnum;
1494                         }
1495                 }
1496         }
1497 }
1498
1499 #if TRAVERSALS_TAKE_TRANSACTION_LOCK
1500 struct traverse_dep {
1501         unsigned int file;
1502         unsigned int op_num;
1503 };
1504
1505 /* Force an order among the traversals, so they don't deadlock (as much) */
1506 static void make_traverse_depends(char *filename[],
1507                                   struct op *op[], unsigned int num_ops[],
1508                                   unsigned int num)
1509 {
1510         unsigned int i, num_traversals = 0;
1511         int j;
1512         struct traverse_dep *dep;
1513
1514         /* Sort by which one runs first. */
1515         int compare_traverse_dep(const void *_a, const void *_b)
1516         {
1517                 const struct traverse_dep *ta = _a, *tb = _b;
1518                 const struct op *a = &op[ta->file][ta->op_num],
1519                         *b = &op[tb->file][tb->op_num];
1520
1521                 if (a->serial != b->serial)
1522                         return a->serial - b->serial;
1523
1524                 /* If they have same serial, it means one didn't make any
1525                  * changes.  Thus sort by end in that case. */
1526                 return a[a->group_len].serial - b[b->group_len].serial;
1527         }
1528
1529         dep = talloc_array(NULL, struct traverse_dep, 1);
1530
1531         /* Count them. */
1532         for (i = 0; i < num; i++) {
1533                 for (j = 1; j < num_ops[i]; j++) {
1534                         /* Traverse start (ignore those in
1535                          * transactions; they're already covered by
1536                          * transaction dependencies). */
1537                         if (starts_traverse(&op[i][j])
1538                             && !in_transaction(op[i], j)) {
1539                                 dep = talloc_realloc(NULL, dep,
1540                                                      struct traverse_dep,
1541                                                      num_traversals+1);
1542                                 dep[num_traversals].file = i;
1543                                 dep[num_traversals].op_num = j;
1544                                 num_traversals++;
1545                         }
1546                 }
1547         }
1548         qsort(dep, num_traversals, sizeof(dep[0]), compare_traverse_dep);
1549
1550         for (i = 1; i < num_traversals; i++) {
1551                 const struct op *prev = &op[dep[i-1].file][dep[i-1].op_num];
1552                 const struct op *curr = &op[dep[i].file][dep[i].op_num];
1553
1554                 /* Read traverses don't depend on each other (read lock). */
1555                 if (prev->op == OP_TDB_TRAVERSE_READ_START
1556                     && curr->op == OP_TDB_TRAVERSE_READ_START)
1557                         continue;
1558
1559                 /* Only make dependency if it's clear. */
1560                 if (compare_traverse_dep(&dep[i], &dep[i-1])) {
1561                         /* i depends on end of traverse i-1. */
1562                         add_dependency(NULL, op, filename,
1563                                        dep[i].file, dep[i].op_num,
1564                                        dep[i-1].file, dep[i-1].op_num
1565                                        + prev->group_len);
1566                 }
1567         }
1568         talloc_free(dep);
1569 }
1570 #endif
1571
1572 static void derive_dependencies(char *filename[],
1573                                 struct op *op[], unsigned int num_ops[],
1574                                 unsigned int num)
1575 {
1576         struct keyinfo *hash;
1577         unsigned int h, i;
1578
1579         /* Create hash table for faster key lookup. */
1580         hash = hash_ops(op, num_ops, num);
1581
1582         /* Sort them by serial number. */
1583         sort_ops(hash, filename, op, num);
1584
1585         /* Create dependencies back to the last change, rather than
1586          * creating false dependencies by naively making each one
1587          * depend on the previous.  This has two purposes: it makes
1588          * later optimization simpler, and it also avoids deadlock with
1589          * same sequence number ops inside traversals (if one
1590          * traversal doesn't write anything, two ops can have the same
1591          * sequence number yet we can create a traversal dependency
1592          * the other way). */
1593         for (h = 0; h < total_keys * 2; h++) {
1594                 int prev = -1;
1595
1596                 if (hash[h].num_users < 2)
1597                         continue;
1598
1599                 for (i = 0; i < hash[h].num_users; i++) {
1600                         if (changes_db(&hash[h].key, &op[hash[h].user[i].file]
1601                                        [hash[h].user[i].op_num])) {
1602                                 depend_on_previous(op, filename, num,
1603                                                    hash[h].user, i, prev);
1604                                 prev = i;
1605                         } else if (prev >= 0)
1606                                 add_dependency(hash, op, filename,
1607                                                hash[h].user[i].file,
1608                                                hash[h].user[i].op_num,
1609                                                hash[h].user[prev].file,
1610                                                hash[h].user[prev].op_num);
1611                 }
1612         }
1613
1614 #if TRAVERSALS_TAKE_TRANSACTION_LOCK
1615         make_traverse_depends(filename, op, num_ops, num);
1616 #endif
1617
1618         optimize_dependencies(op, num_ops, num);
1619 }
1620
1621 int main(int argc, char *argv[])
1622 {
1623         struct timeval start, end;
1624         unsigned int i, num_ops[argc], hashsize[argc], tdb_flags[argc], open_flags[argc];
1625         struct op *op[argc];
1626         int fds[2];
1627         char c;
1628         bool ok = true;
1629
1630         if (argc < 3)
1631                 errx(1, "Usage: %s <tdbfile> <tracefile>...", argv[0]);
1632
1633         pipes = talloc_array(NULL, struct pipe, argc - 2);
1634         for (i = 0; i < argc - 2; i++) {
1635                 printf("Loading tracefile %s...", argv[2+i]);
1636                 fflush(stdout);
1637                 op[i] = load_tracefile(argv[2+i], &num_ops[i], &hashsize[i],
1638                                        &tdb_flags[i], &open_flags[i]);
1639                 if (pipe(pipes[i].fd) != 0)
1640                         err(1, "creating pipe");
1641                 printf("done\n");
1642         }
1643
1644         printf("Calculating inter-dependencies...");
1645         fflush(stdout);
1646         derive_dependencies(argv+2, op, num_ops, i);
1647         printf("done\n");
1648
1649         /* Don't fork for single arg case: simple debugging. */
1650         if (argc == 3) {
1651                 struct tdb_context *tdb;
1652                 tdb = tdb_open_ex(argv[1], hashsize[0], tdb_flags[0]|TDB_NOSYNC,
1653                                   open_flags[0], 0600, NULL, hash_key);
1654                 printf("Single threaded run...");
1655                 fflush(stdout);
1656
1657                 run_ops(tdb, pipes[0].fd[0], argv+2, op, 0, 1, num_ops[0],
1658                         false);
1659                 check_deps(argv[2], op[0], num_ops[0]);
1660
1661                 printf("done\n");
1662                 exit(0);
1663         }
1664
1665         if (pipe(fds) != 0)
1666                 err(1, "creating pipe");
1667
1668         for (i = 0; i < argc - 2; i++) {
1669                 struct tdb_context *tdb;
1670
1671                 switch (fork()) {
1672                 case -1:
1673                         err(1, "fork failed");
1674                 case 0:
1675                         close(fds[1]);
1676                         tdb = tdb_open_ex(argv[1], hashsize[i],
1677                                           tdb_flags[i]|TDB_NOSYNC,
1678                                           open_flags[i], 0600, NULL, hash_key);
1679                         if (!tdb)
1680                                 err(1, "Opening tdb %s", argv[1]);
1681
1682                         /* This catches parent exiting. */
1683                         if (read(fds[0], &c, 1) != 1)
1684                                 exit(1);
1685                         run_ops(tdb, pipes[i].fd[0], argv+2, op, i, 1,
1686                                 num_ops[i], false);
1687                         check_deps(argv[2+i], op[i], num_ops[i]);
1688                         exit(0);
1689                 default:
1690                         break;
1691                 }
1692         }
1693
1694         /* Let everything settle. */
1695         sleep(1);
1696
1697         printf("Starting run...");
1698         fflush(stdout);
1699         gettimeofday(&start, NULL);
1700         /* Tell them all to go!  Any write of sufficient length will do. */
1701         if (write(fds[1], hashsize, i) != i)
1702                 err(1, "Writing to wakeup pipe");
1703
1704         for (i = 0; i < argc - 2; i++) {
1705                 int status;
1706                 wait(&status);
1707                 if (!WIFEXITED(status)) {
1708                         warnx("Child died with signal %i", WTERMSIG(status));
1709                         ok = false;
1710                 } else if (WEXITSTATUS(status) != 0)
1711                         /* Assume child spat out error. */
1712                         ok = false;
1713         }
1714         if (!ok)
1715                 exit(1);
1716
1717         gettimeofday(&end, NULL);
1718         printf("done\n");
1719
1720         end.tv_sec -= start.tv_sec;
1721         printf("Time replaying: %lu usec\n",
1722                end.tv_sec * 1000000UL + (end.tv_usec - start.tv_usec));
1723
1724         exit(0);
1725 }