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