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: --failpath=%s\n",
 334                                history[i].file, history[i].line,
 335                                failpath_string());
 336                         status = 1;
 337                 }
 338                 history[i].cleanup(&history[i].u);
 339         }
 340
 341         free_everything();
 342         tell_parent(SUCCESS);
 343         exit(status);
 344 }
 345
 346 static bool should_fail(struct failtest_call *call)
 347 {
 348         int status;
 349         int control[2], output[2];
 350         enum info_type type = UNEXPECTED;
 351         char *out = NULL;
 352         size_t outlen = 0;
 353         struct saved_file *files;
 354
 355         /* Are we probing? */
 356         if (probe_count && --probe_count == 0)
 357                 failtest_cleanup(true, 0);
 358
 359         if (call == &unrecorded_call)
 360                 return false;
 361
 362         if (failpath) {
 363                 /* + means continue after end, like normal. */
 364                 if (*failpath == '+')
 365                         failpath = NULL;
 366                 else {
 367                         if (tolower((unsigned char)*failpath)
 368                             != info_to_arg[call->type])
 369                                 errx(1, "Failpath expected '%c' got '%c'\n",
 370                                      info_to_arg[call->type], *failpath);
 371                         call->fail = isupper((unsigned char)*(failpath++));
 372                         return call->fail;
 373                 }
 374         }
 375
 376         /* Attach debugger if they asked for it. */
 377         if (debugpath && history_num == strlen(debugpath)) {
 378                 unsigned int i;
 379
 380                 for (i = 0; i < history_num; i++) {
 381                         unsigned char c = info_to_arg[history[i].type];
 382                         if (history[i].fail)
 383                                 c = toupper(c);
 384                         if (c != debugpath[i])
 385                                 break;
 386                 }
 387                 if (i == history_num) {
 388                         char str[80];
 389
 390                         /* Don't timeout. */
 391                         signal(SIGUSR1, SIG_IGN);
 392                         sprintf(str, "xterm -e gdb /proc/%d/exe %d &",
 393                                 getpid(), getpid());
 394                         system(str);
 395                         sleep(5);
 396                 }
 397         }
 398
 399         if (failtest_hook) {
 400                 switch (failtest_hook(history, history_num)) {
 401                 case FAIL_OK:
 402                         break;
 403                 case FAIL_DONT_FAIL:
 404                         call->fail = false;
 405                         return false;
 406                 case FAIL_PROBE:
 407                         /* Already down probe path?  Stop now. */
 408                         if (probe_count)
 409                                 failtest_cleanup(true, 0);
 410                         /* FIXME: We should run *parent* and run probe until
 411                          * calls match up again. */
 412                         probe_count = 3;
 413                         break;
 414                 default:
 415                         abort();
 416                 }
 417         }
 418
 419         files = save_files();
 420
 421         /* We're going to fail in the child. */
 422         call->fail = true;
 423         if (pipe(control) != 0 || pipe(output) != 0)
 424                 err(1, "opening pipe");
 425
 426         /* Prevent double-printing (in child and parent) */
 427         fflush(stdout);
 428         child = fork();
 429         if (child == -1)
 430                 err(1, "forking failed");
 431
 432         if (child == 0) {
 433                 if (tracefd != -1) {
 434                         struct timeval now;
 435                         const char *p;
 436                         gettimeofday(&now, NULL);
 437                         if (now.tv_usec < start.tv_usec) {
 438                                 now.tv_sec--;
 439                                 now.tv_usec += 1000000;
 440                         }
 441                         now.tv_usec -= start.tv_usec;
 442                         now.tv_sec -= start.tv_sec;
 443                         p = failpath_string();
 444                         trace("%u->%u (%u.%02u): %s (", getppid(), getpid(),
 445                               (int)now.tv_sec, (int)now.tv_usec / 10000, p);
 446                         free((char *)p);
 447                         p = strrchr(history[history_num-1].file, '/');
 448                         if (p)
 449                                 trace("%s", p+1);
 450                         else
 451                                 trace("%s", history[history_num-1].file);
 452                         trace(":%u)\n", history[history_num-1].line);
 453                 }
 454                 close(control[0]);
 455                 close(output[0]);
 456                 dup2(output[1], STDOUT_FILENO);
 457                 dup2(output[1], STDERR_FILENO);
 458                 if (output[1] != STDOUT_FILENO && output[1] != STDERR_FILENO)
 459                         close(output[1]);
 460                 control_fd = control[1];
 461                 return true;
 462         }
 463
 464         signal(SIGUSR1, hand_down);
 465
 466         close(control[1]);
 467         close(output[1]);
 468
 469         /* We grab output so we can display it; we grab writes so we
 470          * can compare. */
 471         do {
 472                 struct pollfd pfd[2];
 473                 int ret;
 474
 475                 pfd[0].fd = output[0];
 476                 pfd[0].events = POLLIN|POLLHUP;
 477                 pfd[1].fd = control[0];
 478                 pfd[1].events = POLLIN|POLLHUP;
 479
 480                 if (type == SUCCESS)
 481                         ret = poll(pfd, 1, failtest_timeout_ms);
 482                 else
 483                         ret = poll(pfd, 2, failtest_timeout_ms);
 484
 485                 if (ret <= 0)
 486                         hand_down(SIGUSR1);
 487
 488                 if (pfd[0].revents & POLLIN) {
 489                         ssize_t len;
 490
 491                         out = realloc(out, outlen + 8192);
 492                         len = read(output[0], out + outlen, 8192);
 493                         outlen += len;
 494                 } else if (type != SUCCESS && (pfd[1].revents & POLLIN)) {
 495                         if (read_all(control[0], &type, sizeof(type))) {
 496                                 if (type == WRITE) {
 497                                         if (!read_write_info(control[0]))
 498                                                 break;
 499                                 } else if (type == RELEASE_LOCKS) {
 500                                         release_locks();
 501                                         /* FIXME: Tell them we're done... */
 502                                 }
 503                         }
 504                 } else if (pfd[0].revents & POLLHUP) {
 505                         break;
 506                 }
 507         } while (type != FAILURE);
 508
 509         close(output[0]);
 510         close(control[0]);
 511         waitpid(child, &status, 0);
 512         if (!WIFEXITED(status)) {
 513                 if (WTERMSIG(status) == SIGUSR1)
 514                         child_fail(out, outlen, "Timed out");
 515                 else
 516                         child_fail(out, outlen, "Killed by signal %u: ",
 517                                    WTERMSIG(status));
 518         }
 519         /* Child printed failure already, just pass up exit code. */
 520         if (type == FAILURE) {
 521                 fprintf(stderr, "%.*s", (int)outlen, out);
 522                 tell_parent(type);
 523                 exit(WEXITSTATUS(status) ? WEXITSTATUS(status) : 1);
 524         }
 525         if (WEXITSTATUS(status) != 0)
 526                 child_fail(out, outlen, "Exited with status %i: ",
 527                            WEXITSTATUS(status));
 528
 529         free(out);
 530         signal(SIGUSR1, SIG_DFL);
 531
 532         restore_files(files);
 533
 534         /* We continue onwards without failing. */
 535         call->fail = false;
 536         return false;
 537 }
 538
 539 static void cleanup_calloc(struct calloc_call *call)
 540 {
 541         free(call->ret);
 542 }
 543
 544 void *failtest_calloc(size_t nmemb, size_t size,
 545                       const char *file, unsigned line)
 546 {
 547         struct failtest_call *p;
 548         struct calloc_call call;
 549         call.nmemb = nmemb;
 550         call.size = size;
 551         p = add_history(FAILTEST_CALLOC, file, line, &call);
 552
 553         if (should_fail(p)) {
 554                 p->u.calloc.ret = NULL;
 555                 p->error = ENOMEM;
 556         } else {
 557                 p->u.calloc.ret = calloc(nmemb, size);
 558                 set_cleanup(p, cleanup_calloc, struct calloc_call);
 559         }
 560         errno = p->error;
 561         return p->u.calloc.ret;
 562 }
 563
 564 static void cleanup_malloc(struct malloc_call *call)
 565 {
 566         free(call->ret);
 567 }
 568
 569 void *failtest_malloc(size_t size, const char *file, unsigned line)
 570 {
 571         struct failtest_call *p;
 572         struct malloc_call call;
 573         call.size = size;
 574
 575         p = add_history(FAILTEST_MALLOC, file, line, &call);
 576         if (should_fail(p)) {
 577                 p->u.calloc.ret = NULL;
 578                 p->error = ENOMEM;
 579         } else {
 580                 p->u.calloc.ret = malloc(size);
 581                 set_cleanup(p, cleanup_malloc, struct malloc_call);
 582         }
 583         errno = p->error;
 584         return p->u.calloc.ret;
 585 }
 586
 587 static void cleanup_realloc(struct realloc_call *call)
 588 {
 589         free(call->ret);
 590 }
 591
 592 /* Walk back and find out if we got this ptr from a previous routine. */
 593 static void fixup_ptr_history(void *ptr, unsigned int last)
 594 {
 595         int i;
 596
 597         /* Start at end of history, work back. */
 598         for (i = last - 1; i >= 0; i--) {
 599                 switch (history[i].type) {
 600                 case FAILTEST_REALLOC:
 601                         if (history[i].u.realloc.ret == ptr) {
 602                                 history[i].cleanup = NULL;
 603                                 return;
 604                         }
 605                         break;
 606                 case FAILTEST_MALLOC:
 607                         if (history[i].u.malloc.ret == ptr) {
 608                                 history[i].cleanup = NULL;
 609                                 return;
 610                         }
 611                         break;
 612                 case FAILTEST_CALLOC:
 613                         if (history[i].u.calloc.ret == ptr) {
 614                                 history[i].cleanup = NULL;
 615                                 return;
 616                         }
 617                         break;
 618                 default:
 619                         break;
 620                 }
 621         }
 622 }
 623
 624 void *failtest_realloc(void *ptr, size_t size, const char *file, unsigned line)
 625 {
 626         struct failtest_call *p;
 627         struct realloc_call call;
 628         call.size = size;
 629         p = add_history(FAILTEST_REALLOC, file, line, &call);
 630
 631         /* FIXME: Try one child moving allocation, one not. */
 632         if (should_fail(p)) {
 633                 p->u.realloc.ret = NULL;
 634                 p->error = ENOMEM;
 635         } else {
 636                 fixup_ptr_history(ptr, history_num-1);
 637                 p->u.realloc.ret = realloc(ptr, size);
 638                 set_cleanup(p, cleanup_realloc, struct realloc_call);
 639         }
 640         errno = p->error;
 641         return p->u.realloc.ret;
 642 }
 643
 644 void failtest_free(void *ptr)
 645 {
 646         fixup_ptr_history(ptr, history_num);
 647         free(ptr);
 648 }
 649
 650 static void cleanup_open(struct open_call *call)
 651 {
 652         close(call->ret);
 653 }
 654
 655 int failtest_open(const char *pathname,
 656                   const char *file, unsigned line, ...)
 657 {
 658         struct failtest_call *p;
 659         struct open_call call;
 660         va_list ap;
 661
 662         call.pathname = strdup(pathname);
 663         va_start(ap, line);
 664         call.flags = va_arg(ap, int);
 665         if (call.flags & O_CREAT) {
 666                 call.mode = va_arg(ap, mode_t);
 667                 va_end(ap);
 668         }
 669         p = add_history(FAILTEST_OPEN, file, line, &call);
 670         /* Avoid memory leak! */
 671         if (p == &unrecorded_call)
 672                 free((char *)call.pathname);
 673         p->u.open.ret = open(pathname, call.flags, call.mode);
 674
 675         if (!failpath && p->u.open.ret == -1) {
 676                 p->fail = false;
 677                 p->error = errno;
 678         } else if (should_fail(p)) {
 679                 close(p->u.open.ret);
 680                 p->u.open.ret = -1;
 681                 /* FIXME: Play with error codes? */
 682                 p->error = EACCES;
 683         } else {
 684                 set_cleanup(p, cleanup_open, struct open_call);
 685         }
 686         errno = p->error;
 687         return p->u.open.ret;
 688 }
 689
 690 static void cleanup_pipe(struct pipe_call *call)
 691 {
 692         if (!call->closed[0])
 693                 close(call->fds[0]);
 694         if (!call->closed[1])
 695                 close(call->fds[1]);
 696 }
 697
 698 int failtest_pipe(int pipefd[2], const char *file, unsigned line)
 699 {
 700         struct failtest_call *p;
 701         struct pipe_call call;
 702
 703         p = add_history(FAILTEST_PIPE, file, line, &call);
 704         if (should_fail(p)) {
 705                 p->u.open.ret = -1;
 706                 /* FIXME: Play with error codes? */
 707                 p->error = EMFILE;
 708         } else {
 709                 p->u.pipe.ret = pipe(p->u.pipe.fds);
 710                 p->u.pipe.closed[0] = p->u.pipe.closed[1] = false;
 711                 set_cleanup(p, cleanup_pipe, struct pipe_call);
 712         }
 713         /* This causes valgrind to notice if they use pipefd[] after failure */
 714         memcpy(pipefd, p->u.pipe.fds, sizeof(p->u.pipe.fds));
 715         errno = p->error;
 716         return p->u.pipe.ret;
 717 }
 718
 719 ssize_t failtest_pread(int fd, void *buf, size_t count, off_t off,
 720                        const char *file, unsigned line)
 721 {
 722         struct failtest_call *p;
 723         struct read_call call;
 724         call.fd = fd;
 725         call.buf = buf;
 726         call.count = count;
 727         call.off = off;
 728         p = add_history(FAILTEST_READ, file, line, &call);
 729
 730         /* FIXME: Try partial read returns. */
 731         if (should_fail(p)) {
 732                 p->u.read.ret = -1;
 733                 p->error = EIO;
 734         } else {
 735                 p->u.read.ret = pread(fd, buf, count, off);
 736         }
 737         errno = p->error;
 738         return p->u.read.ret;
 739 }
 740
 741 ssize_t failtest_pwrite(int fd, const void *buf, size_t count, off_t off,
 742                         const char *file, unsigned line)
 743 {
 744         struct failtest_call *p;
 745         struct write_call call;
 746
 747         call.fd = fd;
 748         call.buf = buf;
 749         call.count = count;
 750         call.off = off;
 751         p = add_history(FAILTEST_WRITE, file, line, &call);
 752
 753         /* If we're a child, we need to make sure we write the same thing
 754          * to non-files as the parent does, so tell it. */
 755         if (control_fd != -1 && off == (off_t)-1) {
 756                 enum info_type type = WRITE;
 757
 758                 write_all(control_fd, &type, sizeof(type));
 759                 write_all(control_fd, &p->u.write, sizeof(p->u.write));
 760                 write_all(control_fd, buf, count);
 761         }
 762
 763         /* FIXME: Try partial write returns. */
 764         if (should_fail(p)) {
 765                 p->u.write.ret = -1;
 766                 p->error = EIO;
 767         } else {
 768                 /* FIXME: We assume same write order in parent and child */
 769                 if (off == (off_t)-1 && child_writes_num != 0) {
 770                         if (child_writes[0].fd != fd)
 771                                 errx(1, "Child wrote to fd %u, not %u?",
 772                                      child_writes[0].fd, fd);
 773                         if (child_writes[0].off != p->u.write.off)
 774                                 errx(1, "Child wrote to offset %zu, not %zu?",
 775                                      (size_t)child_writes[0].off,
 776                                      (size_t)p->u.write.off);
 777                         if (child_writes[0].count != count)
 778                                 errx(1, "Child wrote length %zu, not %zu?",
 779                                      child_writes[0].count, count);
 780                         if (memcmp(child_writes[0].buf, buf, count)) {
 781                                 child_fail(NULL, 0,
 782                                            "Child wrote differently to"
 783                                            " fd %u than we did!\n", fd);
 784                         }
 785                         free((char *)child_writes[0].buf);
 786                         child_writes_num--;
 787                         memmove(&child_writes[0], &child_writes[1],
 788                                 sizeof(child_writes[0]) * child_writes_num);
 789
 790                         /* Is this is a socket or pipe, child wrote it
 791                            already. */
 792                         if (p->u.write.off == (off_t)-1) {
 793                                 p->u.write.ret = count;
 794                                 errno = p->error;
 795                                 return p->u.write.ret;
 796                         }
 797                 }
 798                 p->u.write.ret = pwrite(fd, buf, count, off);
 799         }
 800         errno = p->error;
 801         return p->u.write.ret;
 802 }
 803
 804 ssize_t failtest_read(int fd, void *buf, size_t count,
 805                       const char *file, unsigned line)
 806 {
 807         return failtest_pread(fd, buf, count, lseek(fd, 0, SEEK_CUR),
 808                               file, line);
 809 }
 810
 811 ssize_t failtest_write(int fd, const void *buf, size_t count,
 812                        const char *file, unsigned line)
 813 {
 814         return failtest_pwrite(fd, buf, count, lseek(fd, 0, SEEK_CUR),
 815                                file, line);
 816 }
 817
 818 static struct lock_info *WARN_UNUSED_RESULT
 819 add_lock(struct lock_info *locks, int fd, off_t start, off_t end, int type)
 820 {
 821         unsigned int i;
 822         struct lock_info *l;
 823
 824         for (i = 0; i < lock_num; i++) {
 825                 l = &locks[i];
 826
 827                 if (l->fd != fd)
 828                         continue;
 829                 /* Four cases we care about:
 830                  * Start overlap:
 831                  *      l =    |      |
 832                  *      new = |   |
 833                  * Mid overlap:
 834                  *      l =    |      |
 835                  *      new =    |  |
 836                  * End overlap:
 837                  *      l =    |      |
 838                  *      new =      |    |
 839                  * Total overlap:
 840                  *      l =    |      |
 841                  *      new = |         |
 842                  */
 843                 if (start > l->start && end < l->end) {
 844                         /* Mid overlap: trim entry, add new one. */
 845                         off_t new_start, new_end;
 846                         new_start = end + 1;
 847                         new_end = l->end;
 848                         l->end = start - 1;
 849                         locks = add_lock(locks,
 850                                          fd, new_start, new_end, l->type);
 851                         l = &locks[i];
 852                 } else if (start <= l->start && end >= l->end) {
 853                         /* Total overlap: eliminate entry. */
 854                         l->end = 0;
 855                         l->start = 1;
 856                 } else if (end >= l->start && end < l->end) {
 857                         /* Start overlap: trim entry. */
 858                         l->start = end + 1;
 859                 } else if (start > l->start && start <= l->end) {
 860                         /* End overlap: trim entry. */
 861                         l->end = start-1;
 862                 }
 863                 /* Nothing left?  Remove it. */
 864                 if (l->end < l->start) {
 865                         memmove(l, l + 1, (--lock_num - i) * sizeof(l[0]));
 866                         i--;
 867                 }
 868         }
 869
 870         if (type != F_UNLCK) {
 871                 locks = realloc(locks, (lock_num + 1) * sizeof(*locks));
 872                 l = &locks[lock_num++];
 873                 l->fd = fd;
 874                 l->start = start;
 875                 l->end = end;
 876                 l->type = type;
 877         }
 878         return locks;
 879 }
 880
 881 /* We trap this so we can record it: we don't fail it. */
 882 int failtest_close(int fd, const char *file, unsigned line)
 883 {
 884         int i;
 885         struct close_call call;
 886         struct failtest_call *p;
 887
 888         call.fd = fd;
 889         p = add_history(FAILTEST_CLOSE, file, line, &call);
 890         p->fail = false;
 891
 892         /* Consume close from failpath. */
 893         if (failpath)
 894                 if (should_fail(p))
 895                         abort();
 896
 897         if (fd < 0)
 898                 return close(fd);
 899
 900         /* Trace history to find source of fd. */
 901         for (i = history_num-1; i >= 0; i--) {
 902                 switch (history[i].type) {
 903                 case FAILTEST_PIPE:
 904                         /* From a pipe? */
 905                         if (history[i].u.pipe.fds[0] == fd) {
 906                                 assert(!history[i].u.pipe.closed[0]);
 907                                 history[i].u.pipe.closed[0] = true;
 908                                 if (history[i].u.pipe.closed[1])
 909                                         history[i].cleanup = NULL;
 910                                 goto out;
 911                         }
 912                         if (history[i].u.pipe.fds[1] == fd) {
 913                                 assert(!history[i].u.pipe.closed[1]);
 914                                 history[i].u.pipe.closed[1] = true;
 915                                 if (history[i].u.pipe.closed[0])
 916                                         history[i].cleanup = NULL;
 917                                 goto out;
 918                         }
 919                         break;
 920                 case FAILTEST_OPEN:
 921                         if (history[i].u.open.ret == fd) {
 922                                 assert((void *)history[i].cleanup
 923                                        == (void *)cleanup_open);
 924                                 history[i].cleanup = NULL;
 925                                 goto out;
 926                         }
 927                         break;
 928                 default:
 929                         break;
 930                 }
 931         }
 932
 933 out:
 934         locks = add_lock(locks, fd, 0, off_max(), F_UNLCK);
 935         return close(fd);
 936 }
 937
 938 /* Zero length means "to end of file" */
 939 static off_t end_of(off_t start, off_t len)
 940 {
 941         if (len == 0)
 942                 return off_max();
 943         return start + len - 1;
 944 }
 945
 946 /* FIXME: This only handles locks, really. */
 947 int failtest_fcntl(int fd, const char *file, unsigned line, int cmd, ...)
 948 {
 949         struct failtest_call *p;
 950         struct fcntl_call call;
 951         va_list ap;
 952
 953         call.fd = fd;
 954         call.cmd = cmd;
 955
 956         /* Argument extraction. */
 957         switch (cmd) {
 958         case F_SETFL:
 959         case F_SETFD:
 960                 va_start(ap, cmd);
 961                 call.arg.l = va_arg(ap, long);
 962                 va_end(ap);
 963                 return fcntl(fd, cmd, call.arg.l);
 964         case F_GETFD:
 965         case F_GETFL:
 966                 return fcntl(fd, cmd);
 967         case F_GETLK:
 968                 get_locks();
 969                 va_start(ap, cmd);
 970                 call.arg.fl = *va_arg(ap, struct flock *);
 971                 va_end(ap);
 972                 return fcntl(fd, cmd, &call.arg.fl);
 973         case F_SETLK:
 974         case F_SETLKW:
 975                 va_start(ap, cmd);
 976                 call.arg.fl = *va_arg(ap, struct flock *);
 977                 va_end(ap);
 978                 break;
 979         default:
 980                 /* This means you need to implement it here. */
 981                 err(1, "failtest: unknown fcntl %u", cmd);
 982         }
 983
 984         p = add_history(FAILTEST_FCNTL, file, line, &call);
 985
 986         if (should_fail(p)) {
 987                 p->u.fcntl.ret = -1;
 988                 if (p->u.fcntl.cmd == F_SETLK)
 989                         p->error = EAGAIN;
 990                 else
 991                         p->error = EDEADLK;
 992         } else {
 993                 get_locks();
 994                 p->u.fcntl.ret = fcntl(p->u.fcntl.fd, p->u.fcntl.cmd,
 995                                        &p->u.fcntl.arg.fl);
 996                 if (p->u.fcntl.ret == -1)
 997                         p->error = errno;
 998                 else {
 999                         /* We don't handle anything else yet. */
1000                         assert(p->u.fcntl.arg.fl.l_whence == SEEK_SET);
1001                         locks = add_lock(locks,
1002                                          p->u.fcntl.fd,
1003                                          p->u.fcntl.arg.fl.l_start,
1004                                          end_of(p->u.fcntl.arg.fl.l_start,
1005                                                 p->u.fcntl.arg.fl.l_len),
1006                                          p->u.fcntl.arg.fl.l_type);
1007                 }
1008         }
1009         errno = p->error;
1010         return p->u.fcntl.ret;
1011 }
1012
1013 void failtest_init(int argc, char *argv[])
1014 {
1015         unsigned int i;
1016
1017         for (i = 1; i < argc; i++) {
1018                 if (!strncmp(argv[i], "--failpath=", strlen("--failpath="))) {
1019                         failpath = argv[i] + strlen("--failpath=");
1020                 } else if (strcmp(argv[i], "--tracepath") == 0) {
1021                         tracefd = dup(STDERR_FILENO);
1022                         failtest_timeout_ms = -1;
1023                 } else if (!strncmp(argv[i], "--debugpath=",
1024                                     strlen("--debugpath="))) {
1025                         debugpath = argv[i] + strlen("--debugpath=");
1026                 }
1027         }
1028         gettimeofday(&start, NULL);
1029 }
1030
1031 void failtest_exit(int status)
1032 {
1033         if (failtest_exit_check) {
1034                 if (!failtest_exit_check(history, history_num))
1035                         child_fail(NULL, 0, "failtest_exit_check failed\n");
1036         }
1037
1038         failtest_cleanup(false, status);
1039 }