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 <sys/mman.h>
  17 #include <signal.h>
  18 #include <assert.h>
  19 #include <ccan/time/time.h>
  20 #include <ccan/read_write_all/read_write_all.h>
  21 #include <ccan/failtest/failtest_proto.h>
  22 #include <ccan/build_assert/build_assert.h>
  23 #include <ccan/hash/hash.h>
  24 #include <ccan/htable/htable_type.h>
  25 #include <ccan/str/str.h>
  26
  27 enum failtest_result (*failtest_hook)(struct tlist_calls *);
  28
  29 static int tracefd = -1;
  30 static int warnfd;
  31
  32 unsigned int failtest_timeout_ms = 20000;
  33
  34 const char *failpath;
  35 const char *debugpath;
  36
  37 enum info_type {
  38         WRITE,
  39         RELEASE_LOCKS,
  40         FAILURE,
  41         SUCCESS,
  42         UNEXPECTED
  43 };
  44
  45 struct lock_info {
  46         int fd;
  47         /* end is inclusive: you can't have a 0-byte lock. */
  48         off_t start, end;
  49         int type;
  50 };
  51
  52 /* We hash the call location together with its backtrace. */
  53 static size_t hash_call(const struct failtest_call *call)
  54 {
  55         return hash(call->file, strlen(call->file),
  56                     hash(&call->line, 1,
  57                          hash(call->backtrace, call->backtrace_num,
  58                               call->type)));
  59 }
  60
  61 static bool call_eq(const struct failtest_call *call1,
  62                     const struct failtest_call *call2)
  63 {
  64         unsigned int i;
  65
  66         if (strcmp(call1->file, call2->file) != 0
  67             || call1->line != call2->line
  68             || call1->type != call2->type
  69             || call1->backtrace_num != call2->backtrace_num)
  70                 return false;
  71
  72         for (i = 0; i < call1->backtrace_num; i++)
  73                 if (call1->backtrace[i] != call2->backtrace[i])
  74                         return false;
  75
  76         return true;
  77 }
  78
  79 /* Defines struct failtable. */
  80 HTABLE_DEFINE_TYPE(struct failtest_call, (struct failtest_call *), hash_call,
  81                    call_eq, failtable);
  82
  83 bool (*failtest_exit_check)(struct tlist_calls *history);
  84
  85 static struct tlist_calls history = TLIST_INIT(history);
  86 static int control_fd = -1;
  87 static struct timeval start;
  88 static bool probing = false;
  89 static struct failtable failtable;
  90
  91 static struct write_call *child_writes = NULL;
  92 static unsigned int child_writes_num = 0;
  93
  94 static pid_t lock_owner;
  95 static struct lock_info *locks = NULL;
  96 static unsigned int lock_num = 0;
  97
  98 static pid_t orig_pid;
  99
 100 static const char info_to_arg[] = "mceoxprwfa";
 101
 102 /* Dummy call used for failtest_undo wrappers. */
 103 static struct failtest_call unrecorded_call;
 104
 105 #if HAVE_BACKTRACE
 106 #include <execinfo.h>
 107
 108 static void **get_backtrace(unsigned int *num)
 109 {
 110         static unsigned int max_back = 100;
 111         void **ret;
 112
 113 again:
 114         ret = malloc(max_back * sizeof(void *));
 115         *num = backtrace(ret, max_back);
 116         if (*num == max_back) {
 117                 free(ret);
 118                 max_back *= 2;
 119                 goto again;
 120         }
 121         return ret;
 122 }
 123 #else
 124 /* This will test slightly less, since will consider all of the same
 125  * calls as identical.  But, it's slightly faster! */
 126 static void **get_backtrace(unsigned int *num)
 127 {
 128         *num = 0;
 129         return NULL;
 130 }
 131 #endif /* HAVE_BACKTRACE */
 132
 133 static struct failtest_call *add_history_(enum failtest_call_type type,
 134                                           const char *file,
 135                                           unsigned int line,
 136                                           const void *elem,
 137                                           size_t elem_size)
 138 {
 139         struct failtest_call *call;
 140
 141         /* NULL file is how we suppress failure. */
 142         if (!file)
 143                 return &unrecorded_call;
 144
 145         call = malloc(sizeof *call);
 146         call->type = type;
 147         call->file = file;
 148         call->line = line;
 149         call->cleanup = NULL;
 150         call->backtrace = get_backtrace(&call->backtrace_num);
 151         memcpy(&call->u, elem, elem_size);
 152         tlist_add_tail(&history, call, list);
 153         return call;
 154 }
 155
 156 #define add_history(type, file, line, elem) \
 157         add_history_((type), (file), (line), (elem), sizeof(*(elem)))
 158
 159 /* We do a fake call inside a sizeof(), to check types. */
 160 #define set_cleanup(call, clean, type)                  \
 161         (call)->cleanup = (void *)((void)sizeof(clean((type *)NULL),1), (clean))
 162
 163
 164 /* Dup the fd to a high value (out of the way I hope!), and close the old fd. */
 165 static int move_fd_to_high(int fd)
 166 {
 167         int i;
 168
 169         for (i = FD_SETSIZE - 1; i >= 0; i--) {
 170                 if (fcntl(i, F_GETFL) == -1 && errno == EBADF) {
 171                         if (dup2(fd, i) == -1)
 172                                 err(1, "Failed to dup fd %i to %i", fd, i);
 173                         close(fd);
 174                         return i;
 175                 }
 176         }
 177         /* Nothing?  Really?  Er... ok? */
 178         return fd;
 179 }
 180
 181 static bool read_write_info(int fd)
 182 {
 183         struct write_call *w;
 184         char *buf;
 185
 186         /* We don't need all of this, but it's simple. */
 187         child_writes = realloc(child_writes,
 188                                (child_writes_num+1) * sizeof(child_writes[0]));
 189         w = &child_writes[child_writes_num];
 190         if (!read_all(fd, w, sizeof(*w)))
 191                 return false;
 192
 193         w->buf = buf = malloc(w->count);
 194         if (!read_all(fd, buf, w->count))
 195                 return false;
 196
 197         child_writes_num++;
 198         return true;
 199 }
 200
 201 static char *failpath_string(void)
 202 {
 203         struct failtest_call *i;
 204         char *ret = strdup("");
 205         unsigned len = 0;
 206
 207         /* Inefficient, but who cares? */
 208         tlist_for_each(&history, i, list) {
 209                 ret = realloc(ret, len + 2);
 210                 ret[len] = info_to_arg[i->type];
 211                 if (i->fail)
 212                         ret[len] = toupper(ret[len]);
 213                 ret[++len] = '\0';
 214         }
 215         return ret;
 216 }
 217
 218 static void warn_via_fd(int e, const char *fmt, va_list ap)
 219 {
 220         char *p = failpath_string();
 221
 222         vdprintf(warnfd, fmt, ap);
 223         if (e != -1)
 224                 dprintf(warnfd, ": %s", strerror(e));
 225         dprintf(warnfd, " [%s]\n", p);
 226         free(p);
 227 }
 228
 229 static void fwarn(const char *fmt, ...)
 230 {
 231         va_list ap;
 232         int e = errno;
 233
 234         va_start(ap, fmt);
 235         warn_via_fd(e, fmt, ap);
 236         va_end(ap);
 237 }
 238
 239
 240 static void fwarnx(const char *fmt, ...)
 241 {
 242         va_list ap;
 243
 244         va_start(ap, fmt);
 245         warn_via_fd(-1, fmt, ap);
 246         va_end(ap);
 247 }
 248
 249 static void tell_parent(enum info_type type)
 250 {
 251         if (control_fd != -1)
 252                 write_all(control_fd, &type, sizeof(type));
 253 }
 254
 255 static void child_fail(const char *out, size_t outlen, const char *fmt, ...)
 256 {
 257         va_list ap;
 258         char *path = failpath_string();
 259
 260         va_start(ap, fmt);
 261         vfprintf(stderr, fmt, ap);
 262         va_end(ap);
 263
 264         fprintf(stderr, "%.*s", (int)outlen, out);
 265         printf("To reproduce: --failpath=%s\n", path);
 266         free(path);
 267         tell_parent(FAILURE);
 268         exit(1);
 269 }
 270
 271 static void trace(const char *fmt, ...)
 272 {
 273         va_list ap;
 274
 275         if (tracefd == -1)
 276                 return;
 277
 278         va_start(ap, fmt);
 279         vdprintf(tracefd, fmt, ap);
 280         va_end(ap);
 281 }
 282
 283 static pid_t child;
 284
 285 static void hand_down(int signum)
 286 {
 287         kill(child, signum);
 288 }
 289
 290 static void release_locks(void)
 291 {
 292         /* Locks were never acquired/reacquired? */
 293         if (lock_owner == 0)
 294                 return;
 295
 296         /* We own them?  Release them all. */
 297         if (lock_owner == getpid()) {
 298                 unsigned int i;
 299                 struct flock fl;
 300                 fl.l_type = F_UNLCK;
 301                 fl.l_whence = SEEK_SET;
 302                 fl.l_start = 0;
 303                 fl.l_len = 0;
 304
 305                 for (i = 0; i < lock_num; i++)
 306                         fcntl(locks[i].fd, F_SETLK, &fl);
 307         } else {
 308                 /* Our parent must have them; pass request up. */
 309                 enum info_type type = RELEASE_LOCKS;
 310                 assert(control_fd != -1);
 311                 write_all(control_fd, &type, sizeof(type));
 312         }
 313         lock_owner = 0;
 314 }
 315
 316 /* off_t is a signed type.  Getting its max is non-trivial. */
 317 static off_t off_max(void)
 318 {
 319         BUILD_ASSERT(sizeof(off_t) == 4 || sizeof(off_t) == 8);
 320         if (sizeof(off_t) == 4)
 321                 return (off_t)0x7FFFFFF;
 322         else
 323                 return (off_t)0x7FFFFFFFFFFFFFFULL;
 324 }
 325
 326 static void get_locks(void)
 327 {
 328         unsigned int i;
 329         struct flock fl;
 330
 331         if (lock_owner == getpid())
 332                 return;
 333
 334         if (lock_owner != 0) {
 335                 enum info_type type = RELEASE_LOCKS;
 336                 assert(control_fd != -1);
 337                 write_all(control_fd, &type, sizeof(type));
 338         }
 339
 340         fl.l_whence = SEEK_SET;
 341
 342         for (i = 0; i < lock_num; i++) {
 343                 fl.l_type = locks[i].type;
 344                 fl.l_start = locks[i].start;
 345                 if (locks[i].end == off_max())
 346                         fl.l_len = 0;
 347                 else
 348                         fl.l_len = locks[i].end - locks[i].start + 1;
 349
 350                 if (fcntl(locks[i].fd, F_SETLKW, &fl) != 0)
 351                         abort();
 352         }
 353         lock_owner = getpid();
 354 }
 355
 356 struct saved_file {
 357         struct saved_file *next;
 358         int fd;
 359         void *contents;
 360         off_t off, len;
 361 };
 362
 363 static struct saved_file *save_file(struct saved_file *next, int fd)
 364 {
 365         struct saved_file *s = malloc(sizeof(*s));
 366
 367         s->next = next;
 368         s->fd = fd;
 369         s->off = lseek(fd, 0, SEEK_CUR);
 370         /* Special file?  Erk... */
 371         assert(s->off != -1);
 372         s->len = lseek(fd, 0, SEEK_END);
 373         lseek(fd, 0, SEEK_SET);
 374         s->contents = malloc(s->len);
 375         if (read(fd, s->contents, s->len) != s->len)
 376                 err(1, "Failed to save %zu bytes", (size_t)s->len);
 377         lseek(fd, s->off, SEEK_SET);
 378         return s;
 379 }
 380
 381 /* We have little choice but to save and restore open files: mmap means we
 382  * can really intercept changes in the child.
 383  *
 384  * We could do non-mmap'ed files on demand, however. */
 385 static struct saved_file *save_files(void)
 386 {
 387         struct saved_file *files = NULL;
 388         struct failtest_call *i;
 389
 390         /* Figure out the set of live fds. */
 391         tlist_for_each_rev(&history, i, list) {
 392                 if (i->type == FAILTEST_OPEN) {
 393                         int fd = i->u.open.ret;
 394                         /* Only do successful, writable fds. */
 395                         if (fd < 0)
 396                                 continue;
 397
 398                         /* If it was closed, cleanup == NULL. */
 399                         if (!i->cleanup)
 400                                 continue;
 401
 402                         if ((i->u.open.flags & O_RDWR) == O_RDWR) {
 403                                 files = save_file(files, fd);
 404                         } else if ((i->u.open.flags & O_WRONLY)
 405                                    == O_WRONLY) {
 406                                 /* FIXME: Handle O_WRONLY.  Open with O_RDWR? */
 407                                 abort();
 408                         }
 409                 }
 410         }
 411
 412         return files;
 413 }
 414
 415 static void restore_files(struct saved_file *s)
 416 {
 417         while (s) {
 418                 struct saved_file *next = s->next;
 419
 420                 lseek(s->fd, 0, SEEK_SET);
 421                 if (write(s->fd, s->contents, s->len) != s->len)
 422                         err(1, "Failed to restore %zu bytes", (size_t)s->len);
 423                 if (ftruncate(s->fd, s->len) != 0)
 424                         err(1, "Failed to trim file to length %zu",
 425                             (size_t)s->len);
 426                 free(s->contents);
 427                 lseek(s->fd, s->off, SEEK_SET);
 428                 free(s);
 429                 s = next;
 430         }
 431 }
 432
 433 static void free_files(struct saved_file *s)
 434 {
 435         while (s) {
 436                 struct saved_file *next = s->next;
 437                 free(s->contents);
 438                 free(s);
 439                 s = next;
 440         }
 441 }
 442
 443 static void free_call(struct failtest_call *call)
 444 {
 445         /* We don't do this in cleanup: needed even for failed opens. */
 446         if (call->type == FAILTEST_OPEN)
 447                 free((char *)call->u.open.pathname);
 448         free(call->backtrace);
 449         tlist_del_from(&history, call, list);
 450         free(call);
 451 }
 452
 453 /* Free up memory, so valgrind doesn't report leaks. */
 454 static void free_everything(void)
 455 {
 456         struct failtest_call *i;
 457
 458         while ((i = tlist_top(&history, struct failtest_call, list)) != NULL)
 459                 free_call(i);
 460
 461         failtable_clear(&failtable);
 462 }
 463
 464 static NORETURN void failtest_cleanup(bool forced_cleanup, int status)
 465 {
 466         struct failtest_call *i;
 467
 468         /* For children, we don't care if they "failed" the testing. */
 469         if (control_fd != -1)
 470                 status = 0;
 471
 472         if (forced_cleanup) {
 473                 /* We didn't actually do final operation: remove it. */
 474                 i = tlist_tail(&history, struct failtest_call, list);
 475                 free_call(i);
 476         }
 477
 478         /* Cleanup everything, in reverse order. */
 479         tlist_for_each_rev(&history, i, list) {
 480                 if (!i->cleanup)
 481                         continue;
 482                 if (!forced_cleanup) {
 483                         printf("Leak at %s:%u: --failpath=%s\n",
 484                                i->file, i->line, failpath_string());
 485                         status = 1;
 486                 }
 487                 i->cleanup(&i->u);
 488         }
 489
 490         free_everything();
 491         tell_parent(SUCCESS);
 492         exit(status);
 493 }
 494
 495 static bool should_fail(struct failtest_call *call)
 496 {
 497         int status;
 498         int control[2], output[2];
 499         enum info_type type = UNEXPECTED;
 500         char *out = NULL;
 501         size_t outlen = 0;
 502         struct saved_file *files;
 503         struct failtest_call *dup;
 504
 505         if (call == &unrecorded_call)
 506                 return false;
 507
 508         if (failpath) {
 509                 /* + means continue after end, like normal. */
 510                 if (*failpath == '+')
 511                         failpath = NULL;
 512                 else if (*failpath == '\0') {
 513                         /* Continue, but don't inject errors. */
 514                         return call->fail = false;
 515                 } else {
 516                         if (tolower((unsigned char)*failpath)
 517                             != info_to_arg[call->type])
 518                                 errx(1, "Failpath expected '%c' got '%c'\n",
 519                                      info_to_arg[call->type], *failpath);
 520                         call->fail = cisupper(*(failpath++));
 521                         return call->fail;
 522                 }
 523         }
 524
 525         /* Attach debugger if they asked for it. */
 526         if (debugpath) {
 527                 char *path;
 528
 529                 /* Pretend this last call matches whatever path wanted:
 530                  * keeps valgrind happy. */
 531                 call->fail = cisupper(debugpath[strlen(debugpath)-1]);
 532                 path = failpath_string();
 533
 534                 if (streq(path, debugpath)) {
 535                         char str[80];
 536
 537                         /* Don't timeout. */
 538                         signal(SIGUSR1, SIG_IGN);
 539                         sprintf(str, "xterm -e gdb /proc/%d/exe %d &",
 540                                 getpid(), getpid());
 541                         if (system(str) == 0)
 542                                 sleep(5);
 543                 } else {
 544                         /* Ignore last character: could be upper or lower. */
 545                         path[strlen(path)-1] = '\0';
 546                         if (!strstarts(debugpath, path)) {
 547                                 fprintf(stderr,
 548                                         "--debugpath not followed: %s\n", path);
 549                                 debugpath = NULL;
 550                         }
 551                 }
 552                 free(path);
 553         }
 554
 555         /* Are we probing?  If so, we never fail twice. */
 556         if (probing)
 557                 return call->fail = false;
 558
 559         /* Don't more than once in the same place. */
 560         dup = failtable_get(&failtable, call);
 561         if (dup)
 562                 return call->fail = false;
 563
 564         if (failtest_hook) {
 565                 switch (failtest_hook(&history)) {
 566                 case FAIL_OK:
 567                         break;
 568                 case FAIL_PROBE:
 569                         probing = true;
 570                         break;
 571                 case FAIL_DONT_FAIL:
 572                         call->fail = false;
 573                         return false;
 574                 default:
 575                         abort();
 576                 }
 577         }
 578
 579         /* Add it to our table of calls. */
 580         failtable_add(&failtable, call);
 581
 582         files = save_files();
 583
 584         /* We're going to fail in the child. */
 585         call->fail = true;
 586         if (pipe(control) != 0 || pipe(output) != 0)
 587                 err(1, "opening pipe");
 588
 589         /* Prevent double-printing (in child and parent) */
 590         fflush(stdout);
 591         child = fork();
 592         if (child == -1)
 593                 err(1, "forking failed");
 594
 595         if (child == 0) {
 596                 if (tracefd != -1) {
 597                         struct timeval diff;
 598                         const char *p;
 599                         char *failpath;
 600                         struct failtest_call *c;
 601
 602                         c = tlist_tail(&history, struct failtest_call, list);
 603                         diff = time_sub(time_now(), start);
 604                         failpath = failpath_string();
 605                         trace("%u->%u (%u.%02u): %s (", getppid(), getpid(),
 606                               (int)diff.tv_sec, (int)diff.tv_usec / 10000,
 607                               failpath);
 608                         free(failpath);
 609                         p = strrchr(c->file, '/');
 610                         if (p)
 611                                 trace("%s", p+1);
 612                         else
 613                                 trace("%s", c->file);
 614                         trace(":%u)\n", c->line);
 615                 }
 616                 close(control[0]);
 617                 close(output[0]);
 618                 dup2(output[1], STDOUT_FILENO);
 619                 dup2(output[1], STDERR_FILENO);
 620                 if (output[1] != STDOUT_FILENO && output[1] != STDERR_FILENO)
 621                         close(output[1]);
 622                 control_fd = move_fd_to_high(control[1]);
 623                 /* Valgrind spots the leak if we don't free these. */
 624                 free_files(files);
 625                 return true;
 626         }
 627
 628         signal(SIGUSR1, hand_down);
 629
 630         close(control[1]);
 631         close(output[1]);
 632
 633         /* We grab output so we can display it; we grab writes so we
 634          * can compare. */
 635         do {
 636                 struct pollfd pfd[2];
 637                 int ret;
 638
 639                 pfd[0].fd = output[0];
 640                 pfd[0].events = POLLIN|POLLHUP;
 641                 pfd[1].fd = control[0];
 642                 pfd[1].events = POLLIN|POLLHUP;
 643
 644                 if (type == SUCCESS)
 645                         ret = poll(pfd, 1, failtest_timeout_ms);
 646                 else
 647                         ret = poll(pfd, 2, failtest_timeout_ms);
 648
 649                 if (ret == 0)
 650                         hand_down(SIGUSR1);
 651                 if (ret < 0) {
 652                         if (errno == EINTR)
 653                                 continue;
 654                         err(1, "Poll returned %i", ret);
 655                 }
 656
 657                 if (pfd[0].revents & POLLIN) {
 658                         ssize_t len;
 659
 660                         out = realloc(out, outlen + 8192);
 661                         len = read(output[0], out + outlen, 8192);
 662                         outlen += len;
 663                 } else if (type != SUCCESS && (pfd[1].revents & POLLIN)) {
 664                         if (read_all(control[0], &type, sizeof(type))) {
 665                                 if (type == WRITE) {
 666                                         if (!read_write_info(control[0]))
 667                                                 break;
 668                                 } else if (type == RELEASE_LOCKS) {
 669                                         release_locks();
 670                                         /* FIXME: Tell them we're done... */
 671                                 }
 672                         }
 673                 } else if (pfd[0].revents & POLLHUP) {
 674                         break;
 675                 }
 676         } while (type != FAILURE);
 677
 678         close(output[0]);
 679         close(control[0]);
 680         waitpid(child, &status, 0);
 681         if (!WIFEXITED(status)) {
 682                 if (WTERMSIG(status) == SIGUSR1)
 683                         child_fail(out, outlen, "Timed out");
 684                 else
 685                         child_fail(out, outlen, "Killed by signal %u: ",
 686                                    WTERMSIG(status));
 687         }
 688         /* Child printed failure already, just pass up exit code. */
 689         if (type == FAILURE) {
 690                 fprintf(stderr, "%.*s", (int)outlen, out);
 691                 tell_parent(type);
 692                 exit(WEXITSTATUS(status) ? WEXITSTATUS(status) : 1);
 693         }
 694         if (WEXITSTATUS(status) != 0)
 695                 child_fail(out, outlen, "Exited with status %i: ",
 696                            WEXITSTATUS(status));
 697
 698         free(out);
 699         signal(SIGUSR1, SIG_DFL);
 700
 701         restore_files(files);
 702
 703         /* Only child does probe. */
 704         probing = false;
 705
 706         /* We continue onwards without failing. */
 707         call->fail = false;
 708         return false;
 709 }
 710
 711 static void cleanup_calloc(struct calloc_call *call)
 712 {
 713         free(call->ret);
 714 }
 715
 716 void *failtest_calloc(size_t nmemb, size_t size,
 717                       const char *file, unsigned line)
 718 {
 719         struct failtest_call *p;
 720         struct calloc_call call;
 721         call.nmemb = nmemb;
 722         call.size = size;
 723         p = add_history(FAILTEST_CALLOC, file, line, &call);
 724
 725         if (should_fail(p)) {
 726                 p->u.calloc.ret = NULL;
 727                 p->error = ENOMEM;
 728         } else {
 729                 p->u.calloc.ret = calloc(nmemb, size);
 730                 set_cleanup(p, cleanup_calloc, struct calloc_call);
 731         }
 732         errno = p->error;
 733         return p->u.calloc.ret;
 734 }
 735
 736 static void cleanup_malloc(struct malloc_call *call)
 737 {
 738         free(call->ret);
 739 }
 740
 741 void *failtest_malloc(size_t size, const char *file, unsigned line)
 742 {
 743         struct failtest_call *p;
 744         struct malloc_call call;
 745         call.size = size;
 746
 747         p = add_history(FAILTEST_MALLOC, file, line, &call);
 748         if (should_fail(p)) {
 749                 p->u.malloc.ret = NULL;
 750                 p->error = ENOMEM;
 751         } else {
 752                 p->u.malloc.ret = malloc(size);
 753                 set_cleanup(p, cleanup_malloc, struct malloc_call);
 754         }
 755         errno = p->error;
 756         return p->u.malloc.ret;
 757 }
 758
 759 static void cleanup_realloc(struct realloc_call *call)
 760 {
 761         free(call->ret);
 762 }
 763
 764 /* Walk back and find out if we got this ptr from a previous routine. */
 765 static void fixup_ptr_history(void *ptr)
 766 {
 767         struct failtest_call *i;
 768
 769         /* Start at end of history, work back. */
 770         tlist_for_each_rev(&history, i, list) {
 771                 switch (i->type) {
 772                 case FAILTEST_REALLOC:
 773                         if (i->u.realloc.ret == ptr) {
 774                                 i->cleanup = NULL;
 775                                 return;
 776                         }
 777                         break;
 778                 case FAILTEST_MALLOC:
 779                         if (i->u.malloc.ret == ptr) {
 780                                 i->cleanup = NULL;
 781                                 return;
 782                         }
 783                         break;
 784                 case FAILTEST_CALLOC:
 785                         if (i->u.calloc.ret == ptr) {
 786                                 i->cleanup = NULL;
 787                                 return;
 788                         }
 789                         break;
 790                 default:
 791                         break;
 792                 }
 793         }
 794 }
 795
 796 void *failtest_realloc(void *ptr, size_t size, const char *file, unsigned line)
 797 {
 798         struct failtest_call *p;
 799         struct realloc_call call;
 800         call.size = size;
 801         p = add_history(FAILTEST_REALLOC, file, line, &call);
 802
 803         /* FIXME: Try one child moving allocation, one not. */
 804         if (should_fail(p)) {
 805                 p->u.realloc.ret = NULL;
 806                 p->error = ENOMEM;
 807         } else {
 808                 /* Don't catch this one in the history fixup... */
 809                 p->u.realloc.ret = NULL;
 810                 fixup_ptr_history(ptr);
 811                 p->u.realloc.ret = realloc(ptr, size);
 812                 set_cleanup(p, cleanup_realloc, struct realloc_call);
 813         }
 814         errno = p->error;
 815         return p->u.realloc.ret;
 816 }
 817
 818 void failtest_free(void *ptr)
 819 {
 820         fixup_ptr_history(ptr);
 821         free(ptr);
 822 }
 823
 824 static void cleanup_open(struct open_call *call)
 825 {
 826         close(call->ret);
 827 }
 828
 829 int failtest_open(const char *pathname,
 830                   const char *file, unsigned line, ...)
 831 {
 832         struct failtest_call *p;
 833         struct open_call call;
 834         va_list ap;
 835
 836         call.pathname = strdup(pathname);
 837         va_start(ap, line);
 838         call.flags = va_arg(ap, int);
 839         if (call.flags & O_CREAT) {
 840                 call.mode = va_arg(ap, int);
 841                 va_end(ap);
 842         }
 843         p = add_history(FAILTEST_OPEN, file, line, &call);
 844         /* Avoid memory leak! */
 845         if (p == &unrecorded_call)
 846                 free((char *)call.pathname);
 847         p->u.open.ret = open(pathname, call.flags, call.mode);
 848
 849         if (p->u.open.ret == -1) {
 850                 p->fail = false;
 851                 p->error = errno;
 852         } else if (should_fail(p)) {
 853                 close(p->u.open.ret);
 854                 p->u.open.ret = -1;
 855                 /* FIXME: Play with error codes? */
 856                 p->error = EACCES;
 857         } else {
 858                 set_cleanup(p, cleanup_open, struct open_call);
 859         }
 860         errno = p->error;
 861         return p->u.open.ret;
 862 }
 863
 864 void *failtest_mmap(void *addr, size_t length, int prot, int flags,
 865                     int fd, off_t offset, const char *file, unsigned line)
 866 {
 867         struct failtest_call *p;
 868         struct mmap_call call;
 869
 870         call.addr = addr;
 871         call.length = length;
 872         call.prot = prot;
 873         call.flags = flags;
 874         call.offset = offset;
 875         call.fd = fd;
 876
 877         p = add_history(FAILTEST_MMAP, file, line, &call);
 878         if (should_fail(p)) {
 879                 p->u.mmap.ret = MAP_FAILED;
 880                 p->error = ENOMEM;
 881         } else {
 882                 p->u.mmap.ret = mmap(addr, length, prot, flags, fd, offset);
 883         }
 884         errno = p->error;
 885         return p->u.mmap.ret;
 886 }
 887
 888 static void cleanup_pipe(struct pipe_call *call)
 889 {
 890         if (!call->closed[0])
 891                 close(call->fds[0]);
 892         if (!call->closed[1])
 893                 close(call->fds[1]);
 894 }
 895
 896 int failtest_pipe(int pipefd[2], const char *file, unsigned line)
 897 {
 898         struct failtest_call *p;
 899         struct pipe_call call;
 900
 901         p = add_history(FAILTEST_PIPE, file, line, &call);
 902         if (should_fail(p)) {
 903                 p->u.open.ret = -1;
 904                 /* FIXME: Play with error codes? */
 905                 p->error = EMFILE;
 906         } else {
 907                 p->u.pipe.ret = pipe(p->u.pipe.fds);
 908                 p->u.pipe.closed[0] = p->u.pipe.closed[1] = false;
 909                 set_cleanup(p, cleanup_pipe, struct pipe_call);
 910         }
 911         /* This causes valgrind to notice if they use pipefd[] after failure */
 912         memcpy(pipefd, p->u.pipe.fds, sizeof(p->u.pipe.fds));
 913         errno = p->error;
 914         return p->u.pipe.ret;
 915 }
 916
 917 ssize_t failtest_pread(int fd, void *buf, size_t count, off_t off,
 918                        const char *file, unsigned line)
 919 {
 920         struct failtest_call *p;
 921         struct read_call call;
 922         call.fd = fd;
 923         call.buf = buf;
 924         call.count = count;
 925         call.off = off;
 926         p = add_history(FAILTEST_READ, file, line, &call);
 927
 928         /* FIXME: Try partial read returns. */
 929         if (should_fail(p)) {
 930                 p->u.read.ret = -1;
 931                 p->error = EIO;
 932         } else {
 933                 p->u.read.ret = pread(fd, buf, count, off);
 934         }
 935         errno = p->error;
 936         return p->u.read.ret;
 937 }
 938
 939 ssize_t failtest_pwrite(int fd, const void *buf, size_t count, off_t off,
 940                         const char *file, unsigned line)
 941 {
 942         struct failtest_call *p;
 943         struct write_call call;
 944
 945         call.fd = fd;
 946         call.buf = buf;
 947         call.count = count;
 948         call.off = off;
 949         p = add_history(FAILTEST_WRITE, file, line, &call);
 950
 951         /* If we're a child, we need to make sure we write the same thing
 952          * to non-files as the parent does, so tell it. */
 953         if (control_fd != -1 && off == (off_t)-1) {
 954                 enum info_type type = WRITE;
 955
 956                 write_all(control_fd, &type, sizeof(type));
 957                 write_all(control_fd, &p->u.write, sizeof(p->u.write));
 958                 write_all(control_fd, buf, count);
 959         }
 960
 961         /* FIXME: Try partial write returns. */
 962         if (should_fail(p)) {
 963                 p->u.write.ret = -1;
 964                 p->error = EIO;
 965         } else {
 966                 /* FIXME: We assume same write order in parent and child */
 967                 if (off == (off_t)-1 && child_writes_num != 0) {
 968                         if (child_writes[0].fd != fd)
 969                                 errx(1, "Child wrote to fd %u, not %u?",
 970                                      child_writes[0].fd, fd);
 971                         if (child_writes[0].off != p->u.write.off)
 972                                 errx(1, "Child wrote to offset %zu, not %zu?",
 973                                      (size_t)child_writes[0].off,
 974                                      (size_t)p->u.write.off);
 975                         if (child_writes[0].count != count)
 976                                 errx(1, "Child wrote length %zu, not %zu?",
 977                                      child_writes[0].count, count);
 978                         if (memcmp(child_writes[0].buf, buf, count)) {
 979                                 child_fail(NULL, 0,
 980                                            "Child wrote differently to"
 981                                            " fd %u than we did!\n", fd);
 982                         }
 983                         free((char *)child_writes[0].buf);
 984                         child_writes_num--;
 985                         memmove(&child_writes[0], &child_writes[1],
 986                                 sizeof(child_writes[0]) * child_writes_num);
 987
 988                         /* Is this is a socket or pipe, child wrote it
 989                            already. */
 990                         if (p->u.write.off == (off_t)-1) {
 991                                 p->u.write.ret = count;
 992                                 errno = p->error;
 993                                 return p->u.write.ret;
 994                         }
 995                 }
 996                 p->u.write.ret = pwrite(fd, buf, count, off);
 997         }
 998         errno = p->error;
 999         return p->u.write.ret;
1000 }
1001
1002 ssize_t failtest_read(int fd, void *buf, size_t count,
1003                       const char *file, unsigned line)
1004 {
1005         return failtest_pread(fd, buf, count, lseek(fd, 0, SEEK_CUR),
1006                               file, line);
1007 }
1008
1009 ssize_t failtest_write(int fd, const void *buf, size_t count,
1010                        const char *file, unsigned line)
1011 {
1012         return failtest_pwrite(fd, buf, count, lseek(fd, 0, SEEK_CUR),
1013                                file, line);
1014 }
1015
1016 static struct lock_info *WARN_UNUSED_RESULT
1017 add_lock(struct lock_info *locks, int fd, off_t start, off_t end, int type)
1018 {
1019         unsigned int i;
1020         struct lock_info *l;
1021
1022         for (i = 0; i < lock_num; i++) {
1023                 l = &locks[i];
1024
1025                 if (l->fd != fd)
1026                         continue;
1027                 /* Four cases we care about:
1028                  * Start overlap:
1029                  *      l =    |      |
1030                  *      new = |   |
1031                  * Mid overlap:
1032                  *      l =    |      |
1033                  *      new =    |  |
1034                  * End overlap:
1035                  *      l =    |      |
1036                  *      new =      |    |
1037                  * Total overlap:
1038                  *      l =    |      |
1039                  *      new = |         |
1040                  */
1041                 if (start > l->start && end < l->end) {
1042                         /* Mid overlap: trim entry, add new one. */
1043                         off_t new_start, new_end;
1044                         new_start = end + 1;
1045                         new_end = l->end;
1046                         l->end = start - 1;
1047                         locks = add_lock(locks,
1048                                          fd, new_start, new_end, l->type);
1049                         l = &locks[i];
1050                 } else if (start <= l->start && end >= l->end) {
1051                         /* Total overlap: eliminate entry. */
1052                         l->end = 0;
1053                         l->start = 1;
1054                 } else if (end >= l->start && end < l->end) {
1055                         /* Start overlap: trim entry. */
1056                         l->start = end + 1;
1057                 } else if (start > l->start && start <= l->end) {
1058                         /* End overlap: trim entry. */
1059                         l->end = start-1;
1060                 }
1061                 /* Nothing left?  Remove it. */
1062                 if (l->end < l->start) {
1063                         memmove(l, l + 1, (--lock_num - i) * sizeof(l[0]));
1064                         i--;
1065                 }
1066         }
1067
1068         if (type != F_UNLCK) {
1069                 locks = realloc(locks, (lock_num + 1) * sizeof(*locks));
1070                 l = &locks[lock_num++];
1071                 l->fd = fd;
1072                 l->start = start;
1073                 l->end = end;
1074                 l->type = type;
1075         }
1076         return locks;
1077 }
1078
1079 /* We trap this so we can record it: we don't fail it. */
1080 int failtest_close(int fd, const char *file, unsigned line)
1081 {
1082         struct failtest_call *i;
1083         struct close_call call;
1084         struct failtest_call *p;
1085
1086         call.fd = fd;
1087         p = add_history(FAILTEST_CLOSE, file, line, &call);
1088         p->fail = false;
1089
1090         /* Consume close from failpath. */
1091         if (failpath)
1092                 if (should_fail(p))
1093                         abort();
1094
1095         if (fd < 0)
1096                 return close(fd);
1097
1098         /* Trace history to find source of fd. */
1099         tlist_for_each_rev(&history, i, list) {
1100                 switch (i->type) {
1101                 case FAILTEST_PIPE:
1102                         /* From a pipe? */
1103                         if (i->u.pipe.fds[0] == fd) {
1104                                 assert(!i->u.pipe.closed[0]);
1105                                 i->u.pipe.closed[0] = true;
1106                                 if (i->u.pipe.closed[1])
1107                                         i->cleanup = NULL;
1108                                 goto out;
1109                         }
1110                         if (i->u.pipe.fds[1] == fd) {
1111                                 assert(!i->u.pipe.closed[1]);
1112                                 i->u.pipe.closed[1] = true;
1113                                 if (i->u.pipe.closed[0])
1114                                         i->cleanup = NULL;
1115                                 goto out;
1116                         }
1117                         break;
1118                 case FAILTEST_OPEN:
1119                         if (i->u.open.ret == fd) {
1120                                 assert((void *)i->cleanup
1121                                        == (void *)cleanup_open);
1122                                 i->cleanup = NULL;
1123                                 goto out;
1124                         }
1125                         break;
1126                 default:
1127                         break;
1128                 }
1129         }
1130
1131 out:
1132         locks = add_lock(locks, fd, 0, off_max(), F_UNLCK);
1133         return close(fd);
1134 }
1135
1136 /* Zero length means "to end of file" */
1137 static off_t end_of(off_t start, off_t len)
1138 {
1139         if (len == 0)
1140                 return off_max();
1141         return start + len - 1;
1142 }
1143
1144 /* FIXME: This only handles locks, really. */
1145 int failtest_fcntl(int fd, const char *file, unsigned line, int cmd, ...)
1146 {
1147         struct failtest_call *p;
1148         struct fcntl_call call;
1149         va_list ap;
1150
1151         call.fd = fd;
1152         call.cmd = cmd;
1153
1154         /* Argument extraction. */
1155         switch (cmd) {
1156         case F_SETFL:
1157         case F_SETFD:
1158                 va_start(ap, cmd);
1159                 call.arg.l = va_arg(ap, long);
1160                 va_end(ap);
1161                 return fcntl(fd, cmd, call.arg.l);
1162         case F_GETFD:
1163         case F_GETFL:
1164                 return fcntl(fd, cmd);
1165         case F_GETLK:
1166                 get_locks();
1167                 va_start(ap, cmd);
1168                 call.arg.fl = *va_arg(ap, struct flock *);
1169                 va_end(ap);
1170                 return fcntl(fd, cmd, &call.arg.fl);
1171         case F_SETLK:
1172         case F_SETLKW:
1173                 va_start(ap, cmd);
1174                 call.arg.fl = *va_arg(ap, struct flock *);
1175                 va_end(ap);
1176                 break;
1177         default:
1178                 /* This means you need to implement it here. */
1179                 err(1, "failtest: unknown fcntl %u", cmd);
1180         }
1181
1182         p = add_history(FAILTEST_FCNTL, file, line, &call);
1183
1184         if (should_fail(p)) {
1185                 p->u.fcntl.ret = -1;
1186                 if (p->u.fcntl.cmd == F_SETLK)
1187                         p->error = EAGAIN;
1188                 else
1189                         p->error = EDEADLK;
1190         } else {
1191                 get_locks();
1192                 p->u.fcntl.ret = fcntl(p->u.fcntl.fd, p->u.fcntl.cmd,
1193                                        &p->u.fcntl.arg.fl);
1194                 if (p->u.fcntl.ret == -1)
1195                         p->error = errno;
1196                 else {
1197                         /* We don't handle anything else yet. */
1198                         assert(p->u.fcntl.arg.fl.l_whence == SEEK_SET);
1199                         locks = add_lock(locks,
1200                                          p->u.fcntl.fd,
1201                                          p->u.fcntl.arg.fl.l_start,
1202                                          end_of(p->u.fcntl.arg.fl.l_start,
1203                                                 p->u.fcntl.arg.fl.l_len),
1204                                          p->u.fcntl.arg.fl.l_type);
1205                 }
1206         }
1207         errno = p->error;
1208         return p->u.fcntl.ret;
1209 }
1210
1211 pid_t failtest_getpid(const char *file, unsigned line)
1212 {
1213         /* You must call failtest_init first! */
1214         assert(orig_pid);
1215         return orig_pid;
1216 }
1217
1218 void failtest_init(int argc, char *argv[])
1219 {
1220         unsigned int i;
1221
1222         orig_pid = getpid();
1223
1224         warnfd = move_fd_to_high(dup(STDERR_FILENO));
1225         for (i = 1; i < argc; i++) {
1226                 if (!strncmp(argv[i], "--failpath=", strlen("--failpath="))) {
1227                         failpath = argv[i] + strlen("--failpath=");
1228                 } else if (strcmp(argv[i], "--tracepath") == 0) {
1229                         tracefd = warnfd;
1230                         failtest_timeout_ms = -1;
1231                 } else if (!strncmp(argv[i], "--debugpath=",
1232                                     strlen("--debugpath="))) {
1233                         debugpath = argv[i] + strlen("--debugpath=");
1234                 }
1235         }
1236         failtable_init(&failtable);
1237         start = time_now();
1238 }
1239
1240 bool failtest_has_failed(void)
1241 {
1242         return control_fd != -1;
1243 }
1244
1245 void failtest_exit(int status)
1246 {
1247         if (failtest_exit_check) {
1248                 if (!failtest_exit_check(&history))
1249                         child_fail(NULL, 0, "failtest_exit_check failed\n");
1250         }
1251
1252         failtest_cleanup(false, status);
1253 }