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

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