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

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