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