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

   1 /* Licensed under LGPL - see LICENSE file for details */
   2 #include <ccan/failtest/failtest.h>
   3 #include <stdarg.h>
   4 #include <string.h>
   5 #include <stdio.h>
   6 #include <stdarg.h>
   7 #include <ctype.h>
   8 #include <err.h>
   9 #include <unistd.h>
  10 #include <poll.h>
  11 #include <errno.h>
  12 #include <sys/types.h>
  13 #include <sys/wait.h>
  14 #include <sys/stat.h>
  15 #include <sys/time.h>
  16 #include <signal.h>
  17 #include <assert.h>
  18 #include <ccan/read_write_all/read_write_all.h>
  19 #include <ccan/failtest/failtest_proto.h>
  20 #include <ccan/build_assert/build_assert.h>
  21
  22 enum failtest_result (*failtest_hook)(struct failtest_call *, unsigned);
  23
  24 static int tracefd = -1;
  25
  26 unsigned int failtest_timeout_ms = 20000;
  27
  28 const char *failpath;
  29 const char *debugpath;
  30
  31 enum info_type {
  32         WRITE,
  33         RELEASE_LOCKS,
  34         FAILURE,
  35         SUCCESS,
  36         UNEXPECTED
  37 };
  38
  39 struct lock_info {
  40         int fd;
  41         /* end is inclusive: you can't have a 0-byte lock. */
  42         off_t start, end;
  43         int type;
  44 };
  45
  46 bool (*failtest_exit_check)(struct failtest_call *history, unsigned num);
  47
  48 static struct failtest_call *history = NULL;
  49 static unsigned int history_num = 0;
  50 static int control_fd = -1;
  51 static struct timeval start;
  52 static unsigned int probe_count = 0;
  53
  54 static struct write_call *child_writes = NULL;
  55 static unsigned int child_writes_num = 0;
  56
  57 static pid_t lock_owner;
  58 static struct lock_info *locks = NULL;
  59 static unsigned int lock_num = 0;
  60
  61 static pid_t orig_pid;
  62
  63 static const char info_to_arg[] = "mceoxprwf";
  64
  65 /* Dummy call used for failtest_undo wrappers. */
  66 static struct failtest_call unrecorded_call;
  67
  68 static struct failtest_call *add_history_(enum failtest_call_type type,
  69                                           const char *file,
  70                                           unsigned int line,
  71                                           const void *elem,
  72                                           size_t elem_size)
  73 {
  74         /* NULL file is how we suppress failure. */
  75         if (!file)
  76                 return &unrecorded_call;
  77
  78         history = realloc(history, (history_num + 1) * sizeof(*history));
  79         history[history_num].type = type;
  80         history[history_num].file = file;
  81         history[history_num].line = line;
  82         history[history_num].cleanup = NULL;
  83         memcpy(&history[history_num].u, elem, elem_size);
  84         return &history[history_num++];
  85 }
  86
  87 #define add_history(type, file, line, elem) \
  88         add_history_((type), (file), (line), (elem), sizeof(*(elem)))
  89
  90 /* We do a fake call inside a sizeof(), to check types. */
  91 #define set_cleanup(call, clean, type)                  \
  92         (call)->cleanup = (void *)((void)sizeof(clean((type *)NULL),1), (clean))
  93
  94 static bool read_write_info(int fd)
  95 {
  96         struct write_call *w;
  97         char *buf;
  98
  99         /* We don't need all of this, but it's simple. */
 100         child_writes = realloc(child_writes,
 101                                (child_writes_num+1) * sizeof(child_writes[0]));
 102         w = &child_writes[child_writes_num];
 103         if (!read_all(fd, w, sizeof(*w)))
 104                 return false;
 105
 106         w->buf = buf = malloc(w->count);
 107         if (!read_all(fd, buf, w->count))
 108                 return false;
 109
 110         child_writes_num++;
 111         return true;
 112 }
 113
 114 static char *failpath_string(void)
 115 {
 116         unsigned int i;
 117         char *ret = malloc(history_num + 1);
 118
 119         for (i = 0; i < history_num; i++) {
 120                 ret[i] = info_to_arg[history[i].type];
 121                 if (history[i].fail)
 122                         ret[i] = toupper(ret[i]);
 123         }
 124         ret[i] = '\0';
 125         return ret;
 126 }
 127
 128 static void tell_parent(enum info_type type)
 129 {
 130         if (control_fd != -1)
 131                 write_all(control_fd, &type, sizeof(type));
 132 }
 133
 134 static void child_fail(const char *out, size_t outlen, const char *fmt, ...)
 135 {
 136         va_list ap;
 137         char *path = failpath_string();
 138
 139         va_start(ap, fmt);
 140         vfprintf(stderr, fmt, ap);
 141         va_end(ap);
 142
 143         fprintf(stderr, "%.*s", (int)outlen, out);
 144         printf("To reproduce: --failpath=%s\n", path);
 145         free(path);
 146         tell_parent(FAILURE);
 147         exit(1);
 148 }
 149
 150 static void trace(const char *fmt, ...)
 151 {
 152         va_list ap;
 153
 154         if (tracefd == -1)
 155                 return;
 156
 157         va_start(ap, fmt);
 158         vdprintf(tracefd, fmt, ap);
 159         va_end(ap);
 160 }
 161
 162 static pid_t child;
 163
 164 static void hand_down(int signum)
 165 {
 166         kill(child, signum);
 167 }
 168
 169 static void release_locks(void)
 170 {
 171         /* Locks were never acquired/reacquired? */
 172         if (lock_owner == 0)
 173                 return;
 174
 175         /* We own them?  Release them all. */
 176         if (lock_owner == getpid()) {
 177                 unsigned int i;
 178                 struct flock fl;
 179                 fl.l_type = F_UNLCK;
 180                 fl.l_whence = SEEK_SET;
 181                 fl.l_start = 0;
 182                 fl.l_len = 0;
 183
 184                 for (i = 0; i < lock_num; i++)
 185                         fcntl(locks[i].fd, F_SETLK, &fl);
 186         } else {
 187                 /* Our parent must have them; pass request up. */
 188                 enum info_type type = RELEASE_LOCKS;
 189                 assert(control_fd != -1);
 190                 write_all(control_fd, &type, sizeof(type));
 191         }
 192         lock_owner = 0;
 193 }
 194
 195 /* off_t is a signed type.  Getting its max is non-trivial. */
 196 static off_t off_max(void)
 197 {
 198         BUILD_ASSERT(sizeof(off_t) == 4 || sizeof(off_t) == 8);
 199         if (sizeof(off_t) == 4)
 200                 return (off_t)0x7FFFFFF;
 201         else
 202                 return (off_t)0x7FFFFFFFFFFFFFFULL;
 203 }
 204
 205 static void get_locks(void)
 206 {
 207         unsigned int i;
 208         struct flock fl;
 209
 210         if (lock_owner == getpid())
 211                 return;
 212
 213         if (lock_owner != 0) {
 214                 enum info_type type = RELEASE_LOCKS;
 215                 assert(control_fd != -1);
 216                 write_all(control_fd, &type, sizeof(type));
 217         }
 218
 219         fl.l_whence = SEEK_SET;
 220
 221         for (i = 0; i < lock_num; i++) {
 222                 fl.l_type = locks[i].type;
 223                 fl.l_start = locks[i].start;
 224                 if (locks[i].end == off_max())
 225                         fl.l_len = 0;
 226                 else
 227                         fl.l_len = locks[i].end - locks[i].start + 1;
 228
 229                 if (fcntl(locks[i].fd, F_SETLKW, &fl) != 0)
 230                         abort();
 231         }
 232         lock_owner = getpid();
 233 }
 234
 235 struct saved_file {
 236         struct saved_file *next;
 237         int fd;
 238         void *contents;
 239         off_t off, len;
 240 };
 241
 242 static struct saved_file *save_file(struct saved_file *next, int fd)
 243 {
 244         struct saved_file *s = malloc(sizeof(*s));
 245
 246         s->next = next;
 247         s->fd = fd;
 248         s->off = lseek(fd, 0, SEEK_CUR);
 249         /* Special file?  Erk... */
 250         assert(s->off != -1);
 251         s->len = lseek(fd, 0, SEEK_END);
 252         lseek(fd, 0, SEEK_SET);
 253         s->contents = malloc(s->len);
 254         if (read(fd, s->contents, s->len) != s->len)
 255                 err(1, "Failed to save %zu bytes", (size_t)s->len);
 256         lseek(fd, s->off, SEEK_SET);
 257         return s;
 258 }
 259
 260 /* We have little choice but to save and restore open files: mmap means we
 261  * can really intercept changes in the child.
 262  *
 263  * We could do non-mmap'ed files on demand, however. */
 264 static struct saved_file *save_files(void)
 265 {
 266         struct saved_file *files = NULL;
 267         int i;
 268
 269         /* Figure out the set of live fds. */
 270         for (i = history_num - 2; i >= 0; i--) {
 271                 if (history[i].type == FAILTEST_OPEN) {
 272                         int fd = history[i].u.open.ret;
 273                         /* Only do successful, writable fds. */
 274                         if (fd < 0)
 275                                 continue;
 276
 277                         /* If it was closed, cleanup == NULL. */
 278                         if (!history[i].cleanup)
 279                                 continue;
 280
 281                         if ((history[i].u.open.flags & O_RDWR) == O_RDWR) {
 282                                 files = save_file(files, fd);
 283                         } else if ((history[i].u.open.flags & O_WRONLY)
 284                                    == O_WRONLY) {
 285                                 /* FIXME: Handle O_WRONLY.  Open with O_RDWR? */
 286                                 abort();
 287                         }
 288                 }
 289         }
 290
 291         return files;
 292 }
 293
 294 static void restore_files(struct saved_file *s)
 295 {
 296         while (s) {
 297                 struct saved_file *next = s->next;
 298
 299                 lseek(s->fd, 0, SEEK_SET);
 300                 if (write(s->fd, s->contents, s->len) != s->len)
 301                         err(1, "Failed to restore %zu bytes", (size_t)s->len);
 302                 if (ftruncate(s->fd, s->len) != 0)
 303                         err(1, "Failed to trim file to length %zu",
 304                             (size_t)s->len);
 305                 free(s->contents);
 306                 lseek(s->fd, s->off, SEEK_SET);
 307                 free(s);
 308                 s = next;
 309         }
 310 }
 311
 312 static void free_files(struct saved_file *s)
 313 {
 314         while (s) {
 315                 struct saved_file *next = s->next;
 316                 free(s->contents);
 317                 free(s);
 318                 s = next;
 319         }
 320 }
 321
 322 /* Free up memory, so valgrind doesn't report leaks. */
 323 static void free_everything(void)
 324 {
 325         unsigned int i;
 326
 327         /* We don't do this in cleanup: needed even for failed opens. */
 328         for (i = 0; i < history_num; i++) {
 329                 if (history[i].type == FAILTEST_OPEN)
 330                         free((char *)history[i].u.open.pathname);
 331         }
 332         free(history);
 333 }
 334
 335 static NORETURN void failtest_cleanup(bool forced_cleanup, int status)
 336 {
 337         int i;
 338
 339         /* For children, we don't care if they "failed" the testing. */
 340         if (control_fd != -1)
 341                 status = 0;
 342
 343         if (forced_cleanup)
 344                 history_num--;
 345
 346         /* Cleanup everything, in reverse order. */
 347         for (i = history_num - 1; i >= 0; i--) {
 348                 if (!history[i].cleanup)
 349                         continue;
 350                 if (!forced_cleanup) {
 351                         printf("Leak at %s:%u: --failpath=%s\n",
 352                                history[i].file, history[i].line,
 353                                failpath_string());
 354                         status = 1;
 355                 }
 356                 history[i].cleanup(&history[i].u);
 357         }
 358
 359         free_everything();
 360         tell_parent(SUCCESS);
 361         exit(status);
 362 }
 363
 364 static bool should_fail(struct failtest_call *call)
 365 {
 366         int status;
 367         int control[2], output[2];
 368         enum info_type type = UNEXPECTED;
 369         char *out = NULL;
 370         size_t outlen = 0;
 371         struct saved_file *files;
 372
 373         /* Are we probing? */
 374         if (probe_count && --probe_count == 0 && control_fd != -1)
 375                 failtest_cleanup(true, 0);
 376
 377         if (call == &unrecorded_call)
 378                 return false;
 379
 380         if (failpath) {
 381                 /* + means continue after end, like normal. */
 382                 if (*failpath == '+')
 383                         failpath = NULL;
 384                 else if (*failpath == '\0') {
 385                         /* Continue, but don't inject errors. */
 386                         return call->fail = false;
 387                 } else {
 388                         if (tolower((unsigned char)*failpath)
 389                             != info_to_arg[call->type])
 390                                 errx(1, "Failpath expected '%c' got '%c'\n",
 391                                      info_to_arg[call->type], *failpath);
 392                         call->fail = isupper((unsigned char)*(failpath++));
 393                         return call->fail;
 394                 }
 395         }
 396
 397         /* Attach debugger if they asked for it. */
 398         if (debugpath && history_num == strlen(debugpath)) {
 399                 unsigned int i;
 400
 401                 for (i = 0; i < history_num; i++) {
 402                         unsigned char c = info_to_arg[history[i].type];
 403                         if (history[i].fail)
 404                                 c = toupper(c);
 405                         if (c != debugpath[i])
 406                                 break;
 407                 }
 408                 if (i == history_num) {
 409                         char str[80];
 410
 411                         /* Don't timeout. */
 412                         signal(SIGUSR1, SIG_IGN);
 413                         sprintf(str, "xterm -e gdb /proc/%d/exe %d &",
 414                                 getpid(), getpid());
 415                         if (system(str) == 0)
 416                                 sleep(5);
 417                 }
 418         }
 419
 420         if (failtest_hook) {
 421                 switch (failtest_hook(history, history_num)) {
 422                 case FAIL_OK:
 423                         break;
 424                 case FAIL_PROBE:
 425                         /* Already down probe path?  Stop now. */
 426                         if (!probe_count) {
 427                                 /* FIXME: We should run *parent* and
 428                                  * run probe until calls match up again. */
 429                                 probe_count = 3;
 430                                 break;
 431                         } else {
 432                                 /* Child should give up now. */
 433                                 if (control_fd != -1)
 434                                         failtest_cleanup(true, 0);
 435                                 /* Parent, don't fail again. */
 436                         }
 437                 case FAIL_DONT_FAIL:
 438                         call->fail = false;
 439                         return false;
 440                 default:
 441                         abort();
 442                 }
 443         }
 444
 445         files = save_files();
 446
 447         /* We're going to fail in the child. */
 448         call->fail = true;
 449         if (pipe(control) != 0 || pipe(output) != 0)
 450                 err(1, "opening pipe");
 451
 452         /* Prevent double-printing (in child and parent) */
 453         fflush(stdout);
 454         child = fork();
 455         if (child == -1)
 456                 err(1, "forking failed");
 457
 458         if (child == 0) {
 459                 if (tracefd != -1) {
 460                         struct timeval now;
 461                         const char *p;
 462                         gettimeofday(&now, NULL);
 463                         if (now.tv_usec < start.tv_usec) {
 464                                 now.tv_sec--;
 465                                 now.tv_usec += 1000000;
 466                         }
 467                         now.tv_usec -= start.tv_usec;
 468                         now.tv_sec -= start.tv_sec;
 469                         p = failpath_string();
 470                         trace("%u->%u (%u.%02u): %s (", getppid(), getpid(),
 471                               (int)now.tv_sec, (int)now.tv_usec / 10000, p);
 472                         free((char *)p);
 473                         p = strrchr(history[history_num-1].file, '/');
 474                         if (p)
 475                                 trace("%s", p+1);
 476                         else
 477                                 trace("%s", history[history_num-1].file);
 478                         trace(":%u)\n", history[history_num-1].line);
 479                 }
 480                 close(control[0]);
 481                 close(output[0]);
 482                 dup2(output[1], STDOUT_FILENO);
 483                 dup2(output[1], STDERR_FILENO);
 484                 if (output[1] != STDOUT_FILENO && output[1] != STDERR_FILENO)
 485                         close(output[1]);
 486                 control_fd = control[1];
 487                 /* Valgrind spots the leak if we don't free these. */
 488                 free_files(files);
 489                 return true;
 490         }
 491
 492         signal(SIGUSR1, hand_down);
 493
 494         close(control[1]);
 495         close(output[1]);
 496
 497         /* We grab output so we can display it; we grab writes so we
 498          * can compare. */
 499         do {
 500                 struct pollfd pfd[2];
 501                 int ret;
 502
 503                 pfd[0].fd = output[0];
 504                 pfd[0].events = POLLIN|POLLHUP;
 505                 pfd[1].fd = control[0];
 506                 pfd[1].events = POLLIN|POLLHUP;
 507
 508                 if (type == SUCCESS)
 509                         ret = poll(pfd, 1, failtest_timeout_ms);
 510                 else
 511                         ret = poll(pfd, 2, failtest_timeout_ms);
 512
 513                 if (ret == 0)
 514                         hand_down(SIGUSR1);
 515                 if (ret < 0) {
 516                         if (errno == EINTR)
 517                                 continue;
 518                         err(1, "Poll returned %i", ret);
 519                 }
 520
 521                 if (pfd[0].revents & POLLIN) {
 522                         ssize_t len;
 523
 524                         out = realloc(out, outlen + 8192);
 525                         len = read(output[0], out + outlen, 8192);
 526                         outlen += len;
 527                 } else if (type != SUCCESS && (pfd[1].revents & POLLIN)) {
 528                         if (read_all(control[0], &type, sizeof(type))) {
 529                                 if (type == WRITE) {
 530                                         if (!read_write_info(control[0]))
 531                                                 break;
 532                                 } else if (type == RELEASE_LOCKS) {
 533                                         release_locks();
 534                                         /* FIXME: Tell them we're done... */
 535                                 }
 536                         }
 537                 } else if (pfd[0].revents & POLLHUP) {
 538                         break;
 539                 }
 540         } while (type != FAILURE);
 541
 542         close(output[0]);
 543         close(control[0]);
 544         waitpid(child, &status, 0);
 545         if (!WIFEXITED(status)) {
 546                 if (WTERMSIG(status) == SIGUSR1)
 547                         child_fail(out, outlen, "Timed out");
 548                 else
 549                         child_fail(out, outlen, "Killed by signal %u: ",
 550                                    WTERMSIG(status));
 551         }
 552         /* Child printed failure already, just pass up exit code. */
 553         if (type == FAILURE) {
 554                 fprintf(stderr, "%.*s", (int)outlen, out);
 555                 tell_parent(type);
 556                 exit(WEXITSTATUS(status) ? WEXITSTATUS(status) : 1);
 557         }
 558         if (WEXITSTATUS(status) != 0)
 559                 child_fail(out, outlen, "Exited with status %i: ",
 560                            WEXITSTATUS(status));
 561
 562         free(out);
 563         signal(SIGUSR1, SIG_DFL);
 564
 565         restore_files(files);
 566
 567         /* We continue onwards without failing. */
 568         call->fail = false;
 569         return false;
 570 }
 571
 572 static void cleanup_calloc(struct calloc_call *call)
 573 {
 574         free(call->ret);
 575 }
 576
 577 void *failtest_calloc(size_t nmemb, size_t size,
 578                       const char *file, unsigned line)
 579 {
 580         struct failtest_call *p;
 581         struct calloc_call call;
 582         call.nmemb = nmemb;
 583         call.size = size;
 584         p = add_history(FAILTEST_CALLOC, file, line, &call);
 585
 586         if (should_fail(p)) {
 587                 p->u.calloc.ret = NULL;
 588                 p->error = ENOMEM;
 589         } else {
 590                 p->u.calloc.ret = calloc(nmemb, size);
 591                 set_cleanup(p, cleanup_calloc, struct calloc_call);
 592         }
 593         errno = p->error;
 594         return p->u.calloc.ret;
 595 }
 596
 597 static void cleanup_malloc(struct malloc_call *call)
 598 {
 599         free(call->ret);
 600 }
 601
 602 void *failtest_malloc(size_t size, const char *file, unsigned line)
 603 {
 604         struct failtest_call *p;
 605         struct malloc_call call;
 606         call.size = size;
 607
 608         p = add_history(FAILTEST_MALLOC, file, line, &call);
 609         if (should_fail(p)) {
 610                 p->u.calloc.ret = NULL;
 611                 p->error = ENOMEM;
 612         } else {
 613                 p->u.calloc.ret = malloc(size);
 614                 set_cleanup(p, cleanup_malloc, struct malloc_call);
 615         }
 616         errno = p->error;
 617         return p->u.calloc.ret;
 618 }
 619
 620 static void cleanup_realloc(struct realloc_call *call)
 621 {
 622         free(call->ret);
 623 }
 624
 625 /* Walk back and find out if we got this ptr from a previous routine. */
 626 static void fixup_ptr_history(void *ptr, unsigned int last)
 627 {
 628         int i;
 629
 630         /* Start at end of history, work back. */
 631         for (i = last - 1; i >= 0; i--) {
 632                 switch (history[i].type) {
 633                 case FAILTEST_REALLOC:
 634                         if (history[i].u.realloc.ret == ptr) {
 635                                 history[i].cleanup = NULL;
 636                                 return;
 637                         }
 638                         break;
 639                 case FAILTEST_MALLOC:
 640                         if (history[i].u.malloc.ret == ptr) {
 641                                 history[i].cleanup = NULL;
 642                                 return;
 643                         }
 644                         break;
 645                 case FAILTEST_CALLOC:
 646                         if (history[i].u.calloc.ret == ptr) {
 647                                 history[i].cleanup = NULL;
 648                                 return;
 649                         }
 650                         break;
 651                 default:
 652                         break;
 653                 }
 654         }
 655 }
 656
 657 void *failtest_realloc(void *ptr, size_t size, const char *file, unsigned line)
 658 {
 659         struct failtest_call *p;
 660         struct realloc_call call;
 661         call.size = size;
 662         p = add_history(FAILTEST_REALLOC, file, line, &call);
 663
 664         /* FIXME: Try one child moving allocation, one not. */
 665         if (should_fail(p)) {
 666                 p->u.realloc.ret = NULL;
 667                 p->error = ENOMEM;
 668         } else {
 669                 fixup_ptr_history(ptr, history_num-1);
 670                 p->u.realloc.ret = realloc(ptr, size);
 671                 set_cleanup(p, cleanup_realloc, struct realloc_call);
 672         }
 673         errno = p->error;
 674         return p->u.realloc.ret;
 675 }
 676
 677 void failtest_free(void *ptr)
 678 {
 679         fixup_ptr_history(ptr, history_num);
 680         free(ptr);
 681 }
 682
 683 static void cleanup_open(struct open_call *call)
 684 {
 685         close(call->ret);
 686 }
 687
 688 int failtest_open(const char *pathname,
 689                   const char *file, unsigned line, ...)
 690 {
 691         struct failtest_call *p;
 692         struct open_call call;
 693         va_list ap;
 694
 695         call.pathname = strdup(pathname);
 696         va_start(ap, line);
 697         call.flags = va_arg(ap, int);
 698         if (call.flags & O_CREAT) {
 699                 call.mode = va_arg(ap, int);
 700                 va_end(ap);
 701         }
 702         p = add_history(FAILTEST_OPEN, file, line, &call);
 703         /* Avoid memory leak! */
 704         if (p == &unrecorded_call)
 705                 free((char *)call.pathname);
 706         p->u.open.ret = open(pathname, call.flags, call.mode);
 707
 708         if (!failpath && p->u.open.ret == -1) {
 709                 p->fail = false;
 710                 p->error = errno;
 711         } else if (should_fail(p)) {
 712                 close(p->u.open.ret);
 713                 p->u.open.ret = -1;
 714                 /* FIXME: Play with error codes? */
 715                 p->error = EACCES;
 716         } else {
 717                 set_cleanup(p, cleanup_open, struct open_call);
 718         }
 719         errno = p->error;
 720         return p->u.open.ret;
 721 }
 722
 723 static void cleanup_pipe(struct pipe_call *call)
 724 {
 725         if (!call->closed[0])
 726                 close(call->fds[0]);
 727         if (!call->closed[1])
 728                 close(call->fds[1]);
 729 }
 730
 731 int failtest_pipe(int pipefd[2], const char *file, unsigned line)
 732 {
 733         struct failtest_call *p;
 734         struct pipe_call call;
 735
 736         p = add_history(FAILTEST_PIPE, file, line, &call);
 737         if (should_fail(p)) {
 738                 p->u.open.ret = -1;
 739                 /* FIXME: Play with error codes? */
 740                 p->error = EMFILE;
 741         } else {
 742                 p->u.pipe.ret = pipe(p->u.pipe.fds);
 743                 p->u.pipe.closed[0] = p->u.pipe.closed[1] = false;
 744                 set_cleanup(p, cleanup_pipe, struct pipe_call);
 745         }
 746         /* This causes valgrind to notice if they use pipefd[] after failure */
 747         memcpy(pipefd, p->u.pipe.fds, sizeof(p->u.pipe.fds));
 748         errno = p->error;
 749         return p->u.pipe.ret;
 750 }
 751
 752 ssize_t failtest_pread(int fd, void *buf, size_t count, off_t off,
 753                        const char *file, unsigned line)
 754 {
 755         struct failtest_call *p;
 756         struct read_call call;
 757         call.fd = fd;
 758         call.buf = buf;
 759         call.count = count;
 760         call.off = off;
 761         p = add_history(FAILTEST_READ, file, line, &call);
 762
 763         /* FIXME: Try partial read returns. */
 764         if (should_fail(p)) {
 765                 p->u.read.ret = -1;
 766                 p->error = EIO;
 767         } else {
 768                 p->u.read.ret = pread(fd, buf, count, off);
 769         }
 770         errno = p->error;
 771         return p->u.read.ret;
 772 }
 773
 774 ssize_t failtest_pwrite(int fd, const void *buf, size_t count, off_t off,
 775                         const char *file, unsigned line)
 776 {
 777         struct failtest_call *p;
 778         struct write_call call;
 779
 780         call.fd = fd;
 781         call.buf = buf;
 782         call.count = count;
 783         call.off = off;
 784         p = add_history(FAILTEST_WRITE, file, line, &call);
 785
 786         /* If we're a child, we need to make sure we write the same thing
 787          * to non-files as the parent does, so tell it. */
 788         if (control_fd != -1 && off == (off_t)-1) {
 789                 enum info_type type = WRITE;
 790
 791                 write_all(control_fd, &type, sizeof(type));
 792                 write_all(control_fd, &p->u.write, sizeof(p->u.write));
 793                 write_all(control_fd, buf, count);
 794         }
 795
 796         /* FIXME: Try partial write returns. */
 797         if (should_fail(p)) {
 798                 p->u.write.ret = -1;
 799                 p->error = EIO;
 800         } else {
 801                 /* FIXME: We assume same write order in parent and child */
 802                 if (off == (off_t)-1 && child_writes_num != 0) {
 803                         if (child_writes[0].fd != fd)
 804                                 errx(1, "Child wrote to fd %u, not %u?",
 805                                      child_writes[0].fd, fd);
 806                         if (child_writes[0].off != p->u.write.off)
 807                                 errx(1, "Child wrote to offset %zu, not %zu?",
 808                                      (size_t)child_writes[0].off,
 809                                      (size_t)p->u.write.off);
 810                         if (child_writes[0].count != count)
 811                                 errx(1, "Child wrote length %zu, not %zu?",
 812                                      child_writes[0].count, count);
 813                         if (memcmp(child_writes[0].buf, buf, count)) {
 814                                 child_fail(NULL, 0,
 815                                            "Child wrote differently to"
 816                                            " fd %u than we did!\n", fd);
 817                         }
 818                         free((char *)child_writes[0].buf);
 819                         child_writes_num--;
 820                         memmove(&child_writes[0], &child_writes[1],
 821                                 sizeof(child_writes[0]) * child_writes_num);
 822
 823                         /* Is this is a socket or pipe, child wrote it
 824                            already. */
 825                         if (p->u.write.off == (off_t)-1) {
 826                                 p->u.write.ret = count;
 827                                 errno = p->error;
 828                                 return p->u.write.ret;
 829                         }
 830                 }
 831                 p->u.write.ret = pwrite(fd, buf, count, off);
 832         }
 833         errno = p->error;
 834         return p->u.write.ret;
 835 }
 836
 837 ssize_t failtest_read(int fd, void *buf, size_t count,
 838                       const char *file, unsigned line)
 839 {
 840         return failtest_pread(fd, buf, count, lseek(fd, 0, SEEK_CUR),
 841                               file, line);
 842 }
 843
 844 ssize_t failtest_write(int fd, const void *buf, size_t count,
 845                        const char *file, unsigned line)
 846 {
 847         return failtest_pwrite(fd, buf, count, lseek(fd, 0, SEEK_CUR),
 848                                file, line);
 849 }
 850
 851 static struct lock_info *WARN_UNUSED_RESULT
 852 add_lock(struct lock_info *locks, int fd, off_t start, off_t end, int type)
 853 {
 854         unsigned int i;
 855         struct lock_info *l;
 856
 857         for (i = 0; i < lock_num; i++) {
 858                 l = &locks[i];
 859
 860                 if (l->fd != fd)
 861                         continue;
 862                 /* Four cases we care about:
 863                  * Start overlap:
 864                  *      l =    |      |
 865                  *      new = |   |
 866                  * Mid overlap:
 867                  *      l =    |      |
 868                  *      new =    |  |
 869                  * End overlap:
 870                  *      l =    |      |
 871                  *      new =      |    |
 872                  * Total overlap:
 873                  *      l =    |      |
 874                  *      new = |         |
 875                  */
 876                 if (start > l->start && end < l->end) {
 877                         /* Mid overlap: trim entry, add new one. */
 878                         off_t new_start, new_end;
 879                         new_start = end + 1;
 880                         new_end = l->end;
 881                         l->end = start - 1;
 882                         locks = add_lock(locks,
 883                                          fd, new_start, new_end, l->type);
 884                         l = &locks[i];
 885                 } else if (start <= l->start && end >= l->end) {
 886                         /* Total overlap: eliminate entry. */
 887                         l->end = 0;
 888                         l->start = 1;
 889                 } else if (end >= l->start && end < l->end) {
 890                         /* Start overlap: trim entry. */
 891                         l->start = end + 1;
 892                 } else if (start > l->start && start <= l->end) {
 893                         /* End overlap: trim entry. */
 894                         l->end = start-1;
 895                 }
 896                 /* Nothing left?  Remove it. */
 897                 if (l->end < l->start) {
 898                         memmove(l, l + 1, (--lock_num - i) * sizeof(l[0]));
 899                         i--;
 900                 }
 901         }
 902
 903         if (type != F_UNLCK) {
 904                 locks = realloc(locks, (lock_num + 1) * sizeof(*locks));
 905                 l = &locks[lock_num++];
 906                 l->fd = fd;
 907                 l->start = start;
 908                 l->end = end;
 909                 l->type = type;
 910         }
 911         return locks;
 912 }
 913
 914 /* We trap this so we can record it: we don't fail it. */
 915 int failtest_close(int fd, const char *file, unsigned line)
 916 {
 917         int i;
 918         struct close_call call;
 919         struct failtest_call *p;
 920
 921         call.fd = fd;
 922         p = add_history(FAILTEST_CLOSE, file, line, &call);
 923         p->fail = false;
 924
 925         /* Consume close from failpath. */
 926         if (failpath)
 927                 if (should_fail(p))
 928                         abort();
 929
 930         if (fd < 0)
 931                 return close(fd);
 932
 933         /* Trace history to find source of fd. */
 934         for (i = history_num-1; i >= 0; i--) {
 935                 switch (history[i].type) {
 936                 case FAILTEST_PIPE:
 937                         /* From a pipe? */
 938                         if (history[i].u.pipe.fds[0] == fd) {
 939                                 assert(!history[i].u.pipe.closed[0]);
 940                                 history[i].u.pipe.closed[0] = true;
 941                                 if (history[i].u.pipe.closed[1])
 942                                         history[i].cleanup = NULL;
 943                                 goto out;
 944                         }
 945                         if (history[i].u.pipe.fds[1] == fd) {
 946                                 assert(!history[i].u.pipe.closed[1]);
 947                                 history[i].u.pipe.closed[1] = true;
 948                                 if (history[i].u.pipe.closed[0])
 949                                         history[i].cleanup = NULL;
 950                                 goto out;
 951                         }
 952                         break;
 953                 case FAILTEST_OPEN:
 954                         if (history[i].u.open.ret == fd) {
 955                                 assert((void *)history[i].cleanup
 956                                        == (void *)cleanup_open);
 957                                 history[i].cleanup = NULL;
 958                                 goto out;
 959                         }
 960                         break;
 961                 default:
 962                         break;
 963                 }
 964         }
 965
 966 out:
 967         locks = add_lock(locks, fd, 0, off_max(), F_UNLCK);
 968         return close(fd);
 969 }
 970
 971 /* Zero length means "to end of file" */
 972 static off_t end_of(off_t start, off_t len)
 973 {
 974         if (len == 0)
 975                 return off_max();
 976         return start + len - 1;
 977 }
 978
 979 /* FIXME: This only handles locks, really. */
 980 int failtest_fcntl(int fd, const char *file, unsigned line, int cmd, ...)
 981 {
 982         struct failtest_call *p;
 983         struct fcntl_call call;
 984         va_list ap;
 985
 986         call.fd = fd;
 987         call.cmd = cmd;
 988
 989         /* Argument extraction. */
 990         switch (cmd) {
 991         case F_SETFL:
 992         case F_SETFD:
 993                 va_start(ap, cmd);
 994                 call.arg.l = va_arg(ap, long);
 995                 va_end(ap);
 996                 return fcntl(fd, cmd, call.arg.l);
 997         case F_GETFD:
 998         case F_GETFL:
 999                 return fcntl(fd, cmd);
1000         case F_GETLK:
1001                 get_locks();
1002                 va_start(ap, cmd);
1003                 call.arg.fl = *va_arg(ap, struct flock *);
1004                 va_end(ap);
1005                 return fcntl(fd, cmd, &call.arg.fl);
1006         case F_SETLK:
1007         case F_SETLKW:
1008                 va_start(ap, cmd);
1009                 call.arg.fl = *va_arg(ap, struct flock *);
1010                 va_end(ap);
1011                 break;
1012         default:
1013                 /* This means you need to implement it here. */
1014                 err(1, "failtest: unknown fcntl %u", cmd);
1015         }
1016
1017         p = add_history(FAILTEST_FCNTL, file, line, &call);
1018
1019         if (should_fail(p)) {
1020                 p->u.fcntl.ret = -1;
1021                 if (p->u.fcntl.cmd == F_SETLK)
1022                         p->error = EAGAIN;
1023                 else
1024                         p->error = EDEADLK;
1025         } else {
1026                 get_locks();
1027                 p->u.fcntl.ret = fcntl(p->u.fcntl.fd, p->u.fcntl.cmd,
1028                                        &p->u.fcntl.arg.fl);
1029                 if (p->u.fcntl.ret == -1)
1030                         p->error = errno;
1031                 else {
1032                         /* We don't handle anything else yet. */
1033                         assert(p->u.fcntl.arg.fl.l_whence == SEEK_SET);
1034                         locks = add_lock(locks,
1035                                          p->u.fcntl.fd,
1036                                          p->u.fcntl.arg.fl.l_start,
1037                                          end_of(p->u.fcntl.arg.fl.l_start,
1038                                                 p->u.fcntl.arg.fl.l_len),
1039                                          p->u.fcntl.arg.fl.l_type);
1040                 }
1041         }
1042         errno = p->error;
1043         return p->u.fcntl.ret;
1044 }
1045
1046 pid_t failtest_getpid(const char *file, unsigned line)
1047 {
1048         /* You must call failtest_init first! */
1049         assert(orig_pid);
1050         return orig_pid;
1051 }
1052
1053 void failtest_init(int argc, char *argv[])
1054 {
1055         unsigned int i;
1056
1057         orig_pid = getpid();
1058
1059         for (i = 1; i < argc; i++) {
1060                 if (!strncmp(argv[i], "--failpath=", strlen("--failpath="))) {
1061                         failpath = argv[i] + strlen("--failpath=");
1062                 } else if (strcmp(argv[i], "--tracepath") == 0) {
1063                         tracefd = dup(STDERR_FILENO);
1064                         failtest_timeout_ms = -1;
1065                 } else if (!strncmp(argv[i], "--debugpath=",
1066                                     strlen("--debugpath="))) {
1067                         debugpath = argv[i] + strlen("--debugpath=");
1068                 }
1069         }
1070         gettimeofday(&start, NULL);
1071 }
1072
1073 bool failtest_has_failed(void)
1074 {
1075         return control_fd != -1;
1076 }
1077
1078 void failtest_exit(int status)
1079 {
1080         if (failtest_exit_check) {
1081                 if (!failtest_exit_check(history, history_num))
1082                         child_fail(NULL, 0, "failtest_exit_check failed\n");
1083         }
1084
1085         failtest_cleanup(false, status);
1086 }