git.ozlabs.org Git - ccan/blob - ccan/failtest/failtest.c

   1 #include <stdarg.h>
   2 #include <string.h>
   3 #include <stdio.h>
   4 #include <stdarg.h>
   5 #include <ctype.h>
   6 #include <err.h>
   7 #include <unistd.h>
   8 #include <poll.h>
   9 #include <errno.h>
  10 #include <sys/types.h>
  11 #include <sys/wait.h>
  12 #include <sys/stat.h>
  13 #include <sys/time.h>
  14 #include <assert.h>
  15 #include <ccan/read_write_all/read_write_all.h>
  16 #include <ccan/failtest/failtest_proto.h>
  17 #include <ccan/failtest/failtest.h>
  18 #include <ccan/build_assert/build_assert.h>
  19
  20 enum failtest_result (*failtest_hook)(struct failtest_call *, unsigned);
  21
  22 static int tracefd = -1;
  23
  24 unsigned int failtest_timeout_ms = 20000;
  25
  26 const char *failpath;
  27 const char *debugpath;
  28
  29 enum info_type {
  30         WRITE,
  31         RELEASE_LOCKS,
  32         FAILURE,
  33         SUCCESS,
  34         UNEXPECTED
  35 };
  36
  37 struct lock_info {
  38         int fd;
  39         /* end is inclusive: you can't have a 0-byte lock. */
  40         off_t start, end;
  41         int type;
  42 };
  43
  44 bool (*failtest_exit_check)(struct failtest_call *history, unsigned num);
  45
  46 static struct failtest_call *history = NULL;
  47 static unsigned int history_num = 0;
  48 static int control_fd = -1;
  49 static struct timeval start;
  50 static unsigned int probe_count = 0;
  51
  52 static struct write_call *child_writes = NULL;
  53 static unsigned int child_writes_num = 0;
  54
  55 static pid_t lock_owner;
  56 static struct lock_info *locks = NULL;
  57 static unsigned int lock_num = 0;
  58
  59 static const char info_to_arg[] = "mceoxprwf";
  60
  61 /* Dummy call used for failtest_undo wrappers. */
  62 static struct failtest_call unrecorded_call;
  63
  64 static struct failtest_call *add_history_(enum failtest_call_type type,
  65                                           const char *file,
  66                                           unsigned int line,
  67                                           const void *elem,
  68                                           size_t elem_size)
  69 {
  70         /* NULL file is how we suppress failure. */
  71         if (!file)
  72                 return &unrecorded_call;
  73
  74         history = realloc(history, (history_num + 1) * sizeof(*history));
  75         history[history_num].type = type;
  76         history[history_num].file = file;
  77         history[history_num].line = line;
  78         history[history_num].cleanup = NULL;
  79         memcpy(&history[history_num].u, elem, elem_size);
  80         return &history[history_num++];
  81 }
  82
  83 #define add_history(type, file, line, elem) \
  84         add_history_((type), (file), (line), (elem), sizeof(*(elem)))
  85
  86 #define set_cleanup(call, clean, type)                  \
  87         (call)->cleanup = (void *)((void)sizeof(clean((type *)NULL)), (clean))
  88
  89 static bool read_write_info(int fd)
  90 {
  91         struct write_call *w;
  92         char *buf;
  93
  94         /* We don't need all of this, but it's simple. */
  95         child_writes = realloc(child_writes,
  96                                (child_writes_num+1) * sizeof(child_writes[0]));
  97         w = &child_writes[child_writes_num];
  98         if (!read_all(fd, w, sizeof(*w)))
  99                 return false;
 100
 101         w->buf = buf = malloc(w->count);
 102         if (!read_all(fd, buf, w->count))
 103                 return false;
 104
 105         child_writes_num++;
 106         return true;
 107 }
 108
 109 static char *failpath_string(void)
 110 {
 111         unsigned int i;
 112         char *ret = malloc(history_num + 1);
 113
 114         for (i = 0; i < history_num; i++) {
 115                 ret[i] = info_to_arg[history[i].type];
 116                 if (history[i].fail)
 117                         ret[i] = toupper(ret[i]);
 118         }
 119         ret[i] = '\0';
 120         return ret;
 121 }
 122
 123 static void tell_parent(enum info_type type)
 124 {
 125         if (control_fd != -1)
 126                 write_all(control_fd, &type, sizeof(type));
 127 }
 128
 129 static void child_fail(const char *out, size_t outlen, const char *fmt, ...)
 130 {
 131         va_list ap;
 132         char *path = failpath_string();
 133
 134         va_start(ap, fmt);
 135         vfprintf(stderr, fmt, ap);
 136         va_end(ap);
 137
 138         fprintf(stderr, "%.*s", (int)outlen, out);
 139         printf("To reproduce: --failpath=%s\n", path);
 140         free(path);
 141         tell_parent(FAILURE);
 142         exit(1);
 143 }
 144
 145 static pid_t child;
 146
 147 static void hand_down(int signal)
 148 {
 149         kill(child, signal);
 150 }
 151
 152 static void release_locks(void)
 153 {
 154         /* Locks were never acquired/reacquired? */
 155         if (lock_owner == 0)
 156                 return;
 157
 158         /* We own them?  Release them all. */
 159         if (lock_owner == getpid()) {
 160                 unsigned int i;
 161                 struct flock fl;
 162                 fl.l_type = F_UNLCK;
 163                 fl.l_whence = SEEK_SET;
 164                 fl.l_start = 0;
 165                 fl.l_len = 0;
 166
 167                 for (i = 0; i < lock_num; i++)
 168                         fcntl(locks[i].fd, F_SETLK, &fl);
 169         } else {
 170                 /* Our parent must have them; pass request up. */
 171                 enum info_type type = RELEASE_LOCKS;
 172                 assert(control_fd != -1);
 173                 write_all(control_fd, &type, sizeof(type));
 174         }
 175         lock_owner = 0;
 176 }
 177
 178 /* off_t is a signed type.  Getting its max is non-trivial. */
 179 static off_t off_max(void)
 180 {
 181         BUILD_ASSERT(sizeof(off_t) == 4 || sizeof(off_t) == 8);
 182         if (sizeof(off_t) == 4)
 183                 return (off_t)0x7FFFFFF;
 184         else
 185                 return (off_t)0x7FFFFFFFFFFFFFFULL;
 186 }
 187
 188 static void get_locks(void)
 189 {
 190         unsigned int i;
 191         struct flock fl;
 192
 193         if (lock_owner == getpid())
 194                 return;
 195
 196         if (lock_owner != 0) {
 197                 enum info_type type = RELEASE_LOCKS;
 198                 assert(control_fd != -1);
 199                 write_all(control_fd, &type, sizeof(type));
 200         }
 201
 202         fl.l_whence = SEEK_SET;
 203
 204         for (i = 0; i < lock_num; i++) {
 205                 fl.l_type = locks[i].type;
 206                 fl.l_start = locks[i].start;
 207                 if (locks[i].end == off_max())
 208                         fl.l_len = 0;
 209                 else
 210                         fl.l_len = locks[i].end - locks[i].start + 1;
 211
 212                 if (fcntl(locks[i].fd, F_SETLKW, &fl) != 0)
 213                         abort();
 214         }
 215         lock_owner = getpid();
 216 }
 217
 218 static void trace_str(const char *str)
 219 {
 220         ssize_t ret;
 221
 222         while ((ret = write(tracefd, str, strlen(str))) <= 0) {
 223                 str += ret;
 224                 if (!*str)
 225                         return;
 226         }
 227         err(1, "Writing trace.");
 228 }
 229
 230 struct saved_file {
 231         struct saved_file *next;
 232         int fd;
 233         void *contents;
 234         off_t off, len;
 235 };
 236
 237 static struct saved_file *save_file(struct saved_file *next, int fd)
 238 {
 239         struct saved_file *s = malloc(sizeof(*s));
 240
 241         s->next = next;
 242         s->fd = fd;
 243         s->off = lseek(fd, 0, SEEK_CUR);
 244         /* Special file?  Erk... */
 245         assert(s->off != -1);
 246         s->len = lseek(fd, 0, SEEK_END);
 247         lseek(fd, 0, SEEK_SET);
 248         s->contents = malloc(s->len);
 249         read(fd, s->contents, s->len);
 250         lseek(fd, s->off, SEEK_SET);
 251         return s;
 252 }
 253
 254 /* We have little choice but to save and restore open files: mmap means we
 255  * can really intercept changes in the child.
 256  *
 257  * We could do non-mmap'ed files on demand, however. */
 258 static struct saved_file *save_files(void)
 259 {
 260         struct saved_file *files = NULL;
 261         int i;
 262
 263         /* Figure out the set of live fds. */
 264         for (i = history_num - 2; i >= 0; i--) {
 265                 if (history[i].type == FAILTEST_OPEN) {
 266                         int fd = history[i].u.open.ret;
 267                         /* Only do successful, writable fds. */
 268                         if (fd < 0)
 269                                 continue;
 270
 271                         /* If it was closed, cleanup == NULL. */
 272                         if (!history[i].cleanup)
 273                                 continue;
 274
 275                         if ((history[i].u.open.flags & O_RDWR) == O_RDWR) {
 276                                 files = save_file(files, fd);
 277                         } else if ((history[i].u.open.flags & O_WRONLY)
 278                                    == O_WRONLY) {
 279                                 /* FIXME: Handle O_WRONLY.  Open with O_RDWR? */
 280                                 abort();
 281                         }
 282                 }
 283         }
 284
 285         return files;
 286 }
 287
 288 static void restore_files(struct saved_file *s)
 289 {
 290         while (s) {
 291                 struct saved_file *next = s->next;
 292
 293                 lseek(s->fd, 0, SEEK_SET);
 294                 write(s->fd, s->contents, s->len);
 295                 ftruncate(s->fd, s->len);
 296                 free(s->contents);
 297                 lseek(s->fd, s->off, SEEK_SET);
 298                 free(s);
 299                 s = next;
 300         }
 301 }
 302
 303 /* Free up memory, so valgrind doesn't report leaks. */
 304 static void free_everything(void)
 305 {
 306         unsigned int i;
 307
 308         /* We don't do this in cleanup: needed even for failed opens. */
 309         for (i = 0; i < history_num; i++) {
 310                 if (history[i].type == FAILTEST_OPEN)
 311                         free((char *)history[i].u.open.pathname);
 312         }
 313         free(history);
 314 }
 315
 316 static NORETURN void failtest_cleanup(bool forced_cleanup, int status)
 317 {
 318         int i;
 319
 320         /* For children, we don't care if they "failed" the testing. */
 321         if (control_fd != -1)
 322                 status = 0;
 323
 324         if (forced_cleanup)
 325                 history_num--;
 326
 327         /* Cleanup everything, in reverse order. */
 328         for (i = history_num - 1; i >= 0; i--) {
 329                 if (!history[i].cleanup)
 330                         continue;
 331                 if (!forced_cleanup) {
 332                         printf("Leak at %s:%u\n",
 333                                history[i].file, history[i].line);
 334                         status = 1;
 335                 }
 336                 history[i].cleanup(&history[i].u);
 337         }
 338
 339         free_everything();
 340         tell_parent(SUCCESS);
 341         exit(status);
 342 }
 343
 344 static bool should_fail(struct failtest_call *call)
 345 {
 346         int status;
 347         int control[2], output[2];
 348         enum info_type type = UNEXPECTED;
 349         char *out = NULL;
 350         size_t outlen = 0;
 351         struct saved_file *files;
 352
 353         /* Are we probing? */
 354         if (probe_count && --probe_count == 0)
 355                 failtest_cleanup(true, 0);
 356
 357         if (call == &unrecorded_call)
 358                 return false;
 359
 360         if (failpath) {
 361                 /* + means continue after end, like normal. */
 362                 if (*failpath == '+')
 363                         failpath = NULL;
 364                 else {
 365                         if (tolower(*failpath) != info_to_arg[call->type])
 366                                 errx(1, "Failpath expected '%c' got '%c'\n",
 367                                      info_to_arg[call->type], *failpath);
 368                         call->fail = isupper(*(failpath++));
 369                         return call->fail;
 370                 }
 371         }
 372
 373         /* Attach debugger if they asked for it. */
 374         if (debugpath && history_num == strlen(debugpath)) {
 375                 unsigned int i;
 376
 377                 for (i = 0; i < history_num; i++) {
 378                         char c = info_to_arg[history[i].type];
 379                         if (history[i].fail)
 380                                 c = toupper(c);
 381                         if (c != debugpath[i])
 382                                 break;
 383                 }
 384                 if (i == history_num) {
 385                         char str[80];
 386
 387                         /* Don't timeout. */
 388                         signal(SIGUSR1, SIG_IGN);
 389                         sprintf(str, "xterm -e gdb /proc/%d/exe %d &",
 390                                 getpid(), getpid());
 391                         system(str);
 392                         sleep(5);
 393                 }
 394         }
 395
 396         if (failtest_hook) {
 397                 switch (failtest_hook(history, history_num)) {
 398                 case FAIL_OK:
 399                         break;
 400                 case FAIL_DONT_FAIL:
 401                         call->fail = false;
 402                         return false;
 403                 case FAIL_PROBE:
 404                         /* Already down probe path?  Stop now. */
 405                         if (probe_count)
 406                                 failtest_cleanup(true, 0);
 407                         /* FIXME: We should run *parent* and run probe until
 408                          * calls match up again. */
 409                         probe_count = 3;
 410                         break;
 411                 default:
 412                         abort();
 413                 }
 414         }
 415
 416         files = save_files();
 417
 418         /* We're going to fail in the child. */
 419         call->fail = true;
 420         if (pipe(control) != 0 || pipe(output) != 0)
 421                 err(1, "opening pipe");
 422
 423         /* Prevent double-printing (in child and parent) */
 424         fflush(stdout);
 425         child = fork();
 426         if (child == -1)
 427                 err(1, "forking failed");
 428
 429         if (child == 0) {
 430                 if (tracefd != -1) {
 431                         struct timeval now;
 432                         char str[50], *p;
 433                         gettimeofday(&now, NULL);
 434                         if (now.tv_usec < start.tv_usec) {
 435                                 now.tv_sec--;
 436                                 now.tv_usec += 1000000;
 437                         }
 438                         now.tv_usec -= start.tv_usec;
 439                         now.tv_sec -= start.tv_sec;
 440                         sprintf(str, "%u (%u.%02u): ", getpid(),
 441                                 (int)now.tv_sec, (int)now.tv_usec / 10000);
 442                         trace_str(str);
 443                         p = failpath_string();
 444                         trace_str(p);
 445                         free(p);
 446                         trace_str("(");
 447                         p = strchr(history[history_num-1].file, '/');
 448                         if (p)
 449                                 trace_str(p+1);
 450                         else
 451                                 trace_str(history[history_num-1].file);
 452                         sprintf(str, ":%u)\n", history[history_num-1].line);
 453                         trace_str(str);
 454                 }
 455                 close(control[0]);
 456                 close(output[0]);
 457                 dup2(output[1], STDOUT_FILENO);
 458                 dup2(output[1], STDERR_FILENO);
 459                 if (output[1] != STDOUT_FILENO && output[1] != STDERR_FILENO)
 460                         close(output[1]);
 461                 control_fd = control[1];
 462                 return true;
 463         }
 464
 465         signal(SIGUSR1, hand_down);
 466
 467         close(control[1]);
 468         close(output[1]);
 469
 470         /* We grab output so we can display it; we grab writes so we
 471          * can compare. */
 472         do {
 473                 struct pollfd pfd[2];
 474                 int ret;
 475
 476                 pfd[0].fd = output[0];
 477                 pfd[0].events = POLLIN|POLLHUP;
 478                 pfd[1].fd = control[0];
 479                 pfd[1].events = POLLIN|POLLHUP;
 480
 481                 if (type == SUCCESS)
 482                         ret = poll(pfd, 1, failtest_timeout_ms);
 483                 else
 484                         ret = poll(pfd, 2, failtest_timeout_ms);
 485
 486                 if (ret <= 0)
 487                         hand_down(SIGUSR1);
 488
 489                 if (pfd[0].revents & POLLIN) {
 490                         ssize_t len;
 491
 492                         out = realloc(out, outlen + 8192);
 493                         len = read(output[0], out + outlen, 8192);
 494                         outlen += len;
 495                 } else if (type != SUCCESS && (pfd[1].revents & POLLIN)) {
 496                         if (read_all(control[0], &type, sizeof(type))) {
 497                                 if (type == WRITE) {
 498                                         if (!read_write_info(control[0]))
 499                                                 break;
 500                                 } else if (type == RELEASE_LOCKS) {
 501                                         release_locks();
 502                                         /* FIXME: Tell them we're done... */
 503                                 }
 504                         }
 505                 } else if (pfd[0].revents & POLLHUP) {
 506                         break;
 507                 }
 508         } while (type != FAILURE);
 509
 510         close(output[0]);
 511         close(control[0]);
 512         waitpid(child, &status, 0);
 513         if (!WIFEXITED(status)) {
 514                 if (WTERMSIG(status) == SIGUSR1)
 515                         child_fail(out, outlen, "Timed out");
 516                 else
 517                         child_fail(out, outlen, "Killed by signal %u: ",
 518                                    WTERMSIG(status));
 519         }
 520         /* Child printed failure already, just pass up exit code. */
 521         if (type == FAILURE) {
 522                 fprintf(stderr, "%.*s", (int)outlen, out);
 523                 tell_parent(type);
 524                 exit(WEXITSTATUS(status) ? WEXITSTATUS(status) : 1);
 525         }
 526         if (WEXITSTATUS(status) != 0)
 527                 child_fail(out, outlen, "Exited with status %i: ",
 528                            WEXITSTATUS(status));
 529
 530         free(out);
 531         signal(SIGUSR1, SIG_DFL);
 532
 533         restore_files(files);
 534
 535         /* We continue onwards without failing. */
 536         call->fail = false;
 537         return false;
 538 }
 539
 540 static void cleanup_calloc(struct calloc_call *call)
 541 {
 542         free(call->ret);
 543 }
 544
 545 void *failtest_calloc(size_t nmemb, size_t size,
 546                       const char *file, unsigned line)
 547 {
 548         struct failtest_call *p;
 549         struct calloc_call call;
 550         call.nmemb = nmemb;
 551         call.size = size;
 552         p = add_history(FAILTEST_CALLOC, file, line, &call);
 553
 554         if (should_fail(p)) {
 555                 p->u.calloc.ret = NULL;
 556                 p->error = ENOMEM;
 557         } else {
 558                 p->u.calloc.ret = calloc(nmemb, size);
 559                 set_cleanup(p, cleanup_calloc, struct calloc_call);
 560         }
 561         errno = p->error;
 562         return p->u.calloc.ret;
 563 }
 564
 565 static void cleanup_malloc(struct malloc_call *call)
 566 {
 567         free(call->ret);
 568 }
 569
 570 void *failtest_malloc(size_t size, const char *file, unsigned line)
 571 {
 572         struct failtest_call *p;
 573         struct malloc_call call;
 574         call.size = size;
 575
 576         p = add_history(FAILTEST_MALLOC, file, line, &call);
 577         if (should_fail(p)) {
 578                 p->u.calloc.ret = NULL;
 579                 p->error = ENOMEM;
 580         } else {
 581                 p->u.calloc.ret = malloc(size);
 582                 set_cleanup(p, cleanup_malloc, struct malloc_call);
 583         }
 584         errno = p->error;
 585         return p->u.calloc.ret;
 586 }
 587
 588 static void cleanup_realloc(struct realloc_call *call)
 589 {
 590         free(call->ret);
 591 }
 592
 593 /* Walk back and find out if we got this ptr from a previous routine. */
 594 static void fixup_ptr_history(void *ptr, unsigned int last)
 595 {
 596         int i;
 597
 598         /* Start at end of history, work back. */
 599         for (i = last - 1; i >= 0; i--) {
 600                 switch (history[i].type) {
 601                 case FAILTEST_REALLOC:
 602                         if (history[i].u.realloc.ret == ptr) {
 603                                 history[i].cleanup = NULL;
 604                                 return;
 605                         }
 606                         break;
 607                 case FAILTEST_MALLOC:
 608                         if (history[i].u.malloc.ret == ptr) {
 609                                 history[i].cleanup = NULL;
 610                                 return;
 611                         }
 612                         break;
 613                 case FAILTEST_CALLOC:
 614                         if (history[i].u.calloc.ret == ptr) {
 615                                 history[i].cleanup = NULL;
 616                                 return;
 617                         }
 618                         break;
 619                 default:
 620                         break;
 621                 }
 622         }
 623 }
 624
 625 void *failtest_realloc(void *ptr, size_t size, const char *file, unsigned line)
 626 {
 627         struct failtest_call *p;
 628         struct realloc_call call;
 629         call.size = size;
 630         p = add_history(FAILTEST_REALLOC, file, line, &call);
 631
 632         /* FIXME: Try one child moving allocation, one not. */
 633         if (should_fail(p)) {
 634                 p->u.realloc.ret = NULL;
 635                 p->error = ENOMEM;
 636         } else {
 637                 fixup_ptr_history(ptr, history_num-1);
 638                 p->u.realloc.ret = realloc(ptr, size);
 639                 set_cleanup(p, cleanup_realloc, struct realloc_call);
 640         }
 641         errno = p->error;
 642         return p->u.realloc.ret;
 643 }
 644
 645 void failtest_free(void *ptr)
 646 {
 647         fixup_ptr_history(ptr, history_num);
 648         free(ptr);
 649 }
 650
 651 static void cleanup_open(struct open_call *call)
 652 {
 653         close(call->ret);
 654 }
 655
 656 int failtest_open(const char *pathname,
 657                   const char *file, unsigned line, ...)
 658 {
 659         struct failtest_call *p;
 660         struct open_call call;
 661         va_list ap;
 662
 663         call.pathname = strdup(pathname);
 664         va_start(ap, line);
 665         call.flags = va_arg(ap, int);
 666         if (call.flags & O_CREAT) {
 667                 call.mode = va_arg(ap, mode_t);
 668                 va_end(ap);
 669         }
 670         p = add_history(FAILTEST_OPEN, file, line, &call);
 671         /* Avoid memory leak! */
 672         if (p == &unrecorded_call)
 673                 free((char *)call.pathname);
 674         p->u.open.ret = open(pathname, call.flags, call.mode);
 675
 676         if (!failpath && p->u.open.ret == -1) {
 677                 p->fail = false;
 678                 p->error = errno;
 679         } else if (should_fail(p)) {
 680                 close(p->u.open.ret);
 681                 p->u.open.ret = -1;
 682                 /* FIXME: Play with error codes? */
 683                 p->error = EACCES;
 684         } else {
 685                 set_cleanup(p, cleanup_open, struct open_call);
 686         }
 687         errno = p->error;
 688         return p->u.open.ret;
 689 }
 690
 691 static void cleanup_pipe(struct pipe_call *call)
 692 {
 693         if (!call->closed[0])
 694                 close(call->fds[0]);
 695         if (!call->closed[1])
 696                 close(call->fds[1]);
 697 }
 698
 699 int failtest_pipe(int pipefd[2], const char *file, unsigned line)
 700 {
 701         struct failtest_call *p;
 702         struct pipe_call call;
 703
 704         p = add_history(FAILTEST_PIPE, file, line, &call);
 705         if (should_fail(p)) {
 706                 p->u.open.ret = -1;
 707                 /* FIXME: Play with error codes? */
 708                 p->error = EMFILE;
 709         } else {
 710                 p->u.pipe.ret = pipe(p->u.pipe.fds);
 711                 p->u.pipe.closed[0] = p->u.pipe.closed[1] = false;
 712                 set_cleanup(p, cleanup_pipe, struct pipe_call);
 713         }
 714         /* This causes valgrind to notice if they use pipefd[] after failure */
 715         memcpy(pipefd, p->u.pipe.fds, sizeof(p->u.pipe.fds));
 716         errno = p->error;
 717         return p->u.pipe.ret;
 718 }
 719
 720 ssize_t failtest_pread(int fd, void *buf, size_t count, off_t off,
 721                        const char *file, unsigned line)
 722 {
 723         struct failtest_call *p;
 724         struct read_call call;
 725         call.fd = fd;
 726         call.buf = buf;
 727         call.count = count;
 728         call.off = off;
 729         p = add_history(FAILTEST_READ, file, line, &call);
 730
 731         /* FIXME: Try partial read returns. */
 732         if (should_fail(p)) {
 733                 p->u.read.ret = -1;
 734                 p->error = EIO;
 735         } else {
 736                 p->u.read.ret = pread(fd, buf, count, off);
 737         }
 738         errno = p->error;
 739         return p->u.read.ret;
 740 }
 741
 742 ssize_t failtest_pwrite(int fd, const void *buf, size_t count, off_t off,
 743                         const char *file, unsigned line)
 744 {
 745         struct failtest_call *p;
 746         struct write_call call;
 747
 748         call.fd = fd;
 749         call.buf = buf;
 750         call.count = count;
 751         call.off = off;
 752         p = add_history(FAILTEST_WRITE, file, line, &call);
 753
 754         /* If we're a child, we need to make sure we write the same thing
 755          * to non-files as the parent does, so tell it. */
 756         if (control_fd != -1 && off == (off_t)-1) {
 757                 enum info_type type = WRITE;
 758
 759                 write_all(control_fd, &type, sizeof(type));
 760                 write_all(control_fd, &p->u.write, sizeof(p->u.write));
 761                 write_all(control_fd, buf, count);
 762         }
 763
 764         /* FIXME: Try partial write returns. */
 765         if (should_fail(p)) {
 766                 p->u.write.ret = -1;
 767                 p->error = EIO;
 768         } else {
 769                 /* FIXME: We assume same write order in parent and child */
 770                 if (off == (off_t)-1 && child_writes_num != 0) {
 771                         if (child_writes[0].fd != fd)
 772                                 errx(1, "Child wrote to fd %u, not %u?",
 773                                      child_writes[0].fd, fd);
 774                         if (child_writes[0].off != p->u.write.off)
 775                                 errx(1, "Child wrote to offset %zu, not %zu?",
 776                                      (size_t)child_writes[0].off,
 777                                      (size_t)p->u.write.off);
 778                         if (child_writes[0].count != count)
 779                                 errx(1, "Child wrote length %zu, not %zu?",
 780                                      child_writes[0].count, count);
 781                         if (memcmp(child_writes[0].buf, buf, count)) {
 782                                 child_fail(NULL, 0,
 783                                            "Child wrote differently to"
 784                                            " fd %u than we did!\n", fd);
 785                         }
 786                         free((char *)child_writes[0].buf);
 787                         child_writes_num--;
 788                         memmove(&child_writes[0], &child_writes[1],
 789                                 sizeof(child_writes[0]) * child_writes_num);
 790
 791                         /* Is this is a socket or pipe, child wrote it
 792                            already. */
 793                         if (p->u.write.off == (off_t)-1) {
 794                                 p->u.write.ret = count;
 795                                 errno = p->error;
 796                                 return p->u.write.ret;
 797                         }
 798                 }
 799                 p->u.write.ret = pwrite(fd, buf, count, off);
 800         }
 801         errno = p->error;
 802         return p->u.write.ret;
 803 }
 804
 805 ssize_t failtest_read(int fd, void *buf, size_t count,
 806                       const char *file, unsigned line)
 807 {
 808         return failtest_pread(fd, buf, count, lseek(fd, 0, SEEK_CUR),
 809                               file, line);
 810 }
 811
 812 ssize_t failtest_write(int fd, const void *buf, size_t count,
 813                        const char *file, unsigned line)
 814 {
 815         return failtest_pwrite(fd, buf, count, lseek(fd, 0, SEEK_CUR),
 816                                file, line);
 817 }
 818
 819 static struct lock_info *WARN_UNUSED_RESULT
 820 add_lock(struct lock_info *locks, int fd, off_t start, off_t end, int type)
 821 {
 822         unsigned int i;
 823         struct lock_info *l;
 824
 825         for (i = 0; i < lock_num; i++) {
 826                 l = &locks[i];
 827
 828                 if (l->fd != fd)
 829                         continue;
 830                 /* Four cases we care about:
 831                  * Start overlap:
 832                  *      l =    |      |
 833                  *      new = |   |
 834                  * Mid overlap:
 835                  *      l =    |      |
 836                  *      new =    |  |
 837                  * End overlap:
 838                  *      l =    |      |
 839                  *      new =      |    |
 840                  * Total overlap:
 841                  *      l =    |      |
 842                  *      new = |         |
 843                  */
 844                 if (start > l->start && end < l->end) {
 845                         /* Mid overlap: trim entry, add new one. */
 846                         off_t new_start, new_end;
 847                         new_start = end + 1;
 848                         new_end = l->end;
 849                         l->end = start - 1;
 850                         locks = add_lock(locks,
 851                                          fd, new_start, new_end, l->type);
 852                         l = &locks[i];
 853                 } else if (start <= l->start && end >= l->end) {
 854                         /* Total overlap: eliminate entry. */
 855                         l->end = 0;
 856                         l->start = 1;
 857                 } else if (end >= l->start && end < l->end) {
 858                         /* Start overlap: trim entry. */
 859                         l->start = end + 1;
 860                 } else if (start > l->start && start <= l->end) {
 861                         /* End overlap: trim entry. */
 862                         l->end = start-1;
 863                 }
 864                 /* Nothing left?  Remove it. */
 865                 if (l->end < l->start) {
 866                         memmove(l, l + 1, (--lock_num - i) * sizeof(l[0]));
 867                         i--;
 868                 }
 869         }
 870
 871         if (type != F_UNLCK) {
 872                 locks = realloc(locks, (lock_num + 1) * sizeof(*locks));
 873                 l = &locks[lock_num++];
 874                 l->fd = fd;
 875                 l->start = start;
 876                 l->end = end;
 877                 l->type = type;
 878         }
 879         return locks;
 880 }
 881
 882 /* We trap this so we can record it: we don't fail it. */
 883 int failtest_close(int fd, const char *file, unsigned line)
 884 {
 885         int i;
 886         struct close_call call;
 887         struct failtest_call *p;
 888
 889         call.fd = fd;
 890         p = add_history(FAILTEST_CLOSE, file, line, &call);
 891         p->fail = false;
 892
 893         /* Consume close from failpath. */
 894         if (failpath)
 895                 if (should_fail(p))
 896                         abort();
 897
 898         if (fd < 0)
 899                 return close(fd);
 900
 901         /* Trace history to find source of fd. */
 902         for (i = history_num-1; i >= 0; i--) {
 903                 switch (history[i].type) {
 904                 case FAILTEST_PIPE:
 905                         /* From a pipe? */
 906                         if (history[i].u.pipe.fds[0] == fd) {
 907                                 assert(!history[i].u.pipe.closed[0]);
 908                                 history[i].u.pipe.closed[0] = true;
 909                                 if (history[i].u.pipe.closed[1])
 910                                         history[i].cleanup = NULL;
 911                                 goto out;
 912                         }
 913                         if (history[i].u.pipe.fds[1] == fd) {
 914                                 assert(!history[i].u.pipe.closed[1]);
 915                                 history[i].u.pipe.closed[1] = true;
 916                                 if (history[i].u.pipe.closed[0])
 917                                         history[i].cleanup = NULL;
 918                                 goto out;
 919                         }
 920                         break;
 921                 case FAILTEST_OPEN:
 922                         if (history[i].u.open.ret == fd) {
 923                                 assert((void *)history[i].cleanup
 924                                        == (void *)cleanup_open);
 925                                 history[i].cleanup = NULL;
 926                                 goto out;
 927                         }
 928                         break;
 929                 default:
 930                         break;
 931                 }
 932         }
 933
 934 out:
 935         locks = add_lock(locks, fd, 0, off_max(), F_UNLCK);
 936         return close(fd);
 937 }
 938
 939 /* Zero length means "to end of file" */
 940 static off_t end_of(off_t start, off_t len)
 941 {
 942         if (len == 0)
 943                 return off_max();
 944         return start + len - 1;
 945 }
 946
 947 /* FIXME: This only handles locks, really. */
 948 int failtest_fcntl(int fd, const char *file, unsigned line, int cmd, ...)
 949 {
 950         struct failtest_call *p;
 951         struct fcntl_call call;
 952         va_list ap;
 953
 954         call.fd = fd;
 955         call.cmd = cmd;
 956
 957         /* Argument extraction. */
 958         switch (cmd) {
 959         case F_SETFL:
 960         case F_SETFD:
 961                 va_start(ap, cmd);
 962                 call.arg.l = va_arg(ap, long);
 963                 va_end(ap);
 964                 return fcntl(fd, cmd, call.arg.l);
 965         case F_GETFD:
 966         case F_GETFL:
 967                 return fcntl(fd, cmd);
 968         case F_GETLK:
 969                 get_locks();
 970                 va_start(ap, cmd);
 971                 call.arg.fl = *va_arg(ap, struct flock *);
 972                 va_end(ap);
 973                 return fcntl(fd, cmd, &call.arg.fl);
 974         case F_SETLK:
 975         case F_SETLKW:
 976                 va_start(ap, cmd);
 977                 call.arg.fl = *va_arg(ap, struct flock *);
 978                 va_end(ap);
 979                 break;
 980         default:
 981                 /* This means you need to implement it here. */
 982                 err(1, "failtest: unknown fcntl %u", cmd);
 983         }
 984
 985         p = add_history(FAILTEST_FCNTL, file, line, &call);
 986         get_locks();
 987
 988         if (should_fail(p)) {
 989                 p->u.fcntl.ret = -1;
 990                 if (p->u.fcntl.cmd == F_SETLK)
 991                         p->error = EAGAIN;
 992                 else
 993                         p->error = EDEADLK;
 994         } else {
 995                 p->u.fcntl.ret = fcntl(p->u.fcntl.fd, p->u.fcntl.cmd,
 996                                        &p->u.fcntl.arg.fl);
 997                 if (p->u.fcntl.ret == -1)
 998                         p->error = errno;
 999                 else {
1000                         /* We don't handle anything else yet. */
1001                         assert(p->u.fcntl.arg.fl.l_whence == SEEK_SET);
1002                         locks = add_lock(locks,
1003                                          p->u.fcntl.fd,
1004                                          p->u.fcntl.arg.fl.l_start,
1005                                          end_of(p->u.fcntl.arg.fl.l_start,
1006                                                 p->u.fcntl.arg.fl.l_len),
1007                                          p->u.fcntl.arg.fl.l_type);
1008                 }
1009         }
1010         errno = p->error;
1011         return p->u.fcntl.ret;
1012 }
1013
1014 void failtest_init(int argc, char *argv[])
1015 {
1016         unsigned int i;
1017
1018         for (i = 1; i < argc; i++) {
1019                 if (!strncmp(argv[i], "--failpath=", strlen("--failpath="))) {
1020                         failpath = argv[i] + strlen("--failpath=");
1021                 } else if (strcmp(argv[i], "--tracepath") == 0) {
1022                         tracefd = dup(STDERR_FILENO);
1023                         failtest_timeout_ms = -1;
1024                 } else if (!strncmp(argv[i], "--debugpath=",
1025                                     strlen("--debugpath="))) {
1026                         debugpath = argv[i] + strlen("--debugpath=");
1027                 }
1028         }
1029         gettimeofday(&start, NULL);
1030 }
1031
1032 void failtest_exit(int status)
1033 {
1034         if (failtest_exit_check) {
1035                 if (!failtest_exit_check(history, history_num))
1036                         child_fail(NULL, 0, "failtest_exit_check failed\n");
1037         }
1038
1039         failtest_cleanup(false, status);
1040 }