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 <assert.h>
  14 #include <ccan/read_write_all/read_write_all.h>
  15 #include <ccan/failtest/failtest_proto.h>
  16 #include <ccan/failtest/failtest.h>
  17 #include <ccan/build_assert/build_assert.h>
  18
  19 bool (*failtest_hook)(struct failtest_call *history, unsigned num)
  20 = failtest_default_hook;
  21
  22 unsigned int failtest_timeout_ms = 20000;
  23
  24 const char *failpath;
  25
  26 enum info_type {
  27         WRITE,
  28         RELEASE_LOCKS,
  29         FAILURE,
  30         SUCCESS,
  31         UNEXPECTED
  32 };
  33
  34 struct write_info_hdr {
  35         size_t len;
  36         off_t offset;
  37         int fd;
  38 };
  39
  40 struct fd_orig {
  41         int fd;
  42         off_t offset;
  43         size_t size;
  44         bool dupped;
  45 };
  46
  47 struct write_info {
  48         struct write_info_hdr hdr;
  49         char *data;
  50         size_t oldlen;
  51         char *olddata;
  52 };
  53
  54 struct lock_info {
  55         int fd;
  56         /* end is inclusive: you can't have a 0-byte lock. */
  57         off_t start, end;
  58         int type;
  59 };
  60
  61 bool (*failtest_exit_check)(struct failtest_call *history, unsigned num);
  62
  63 static struct failtest_call *history = NULL;
  64 static unsigned int history_num = 0;
  65 static int control_fd = -1;
  66
  67 static struct write_info *writes = NULL;
  68 static unsigned int writes_num = 0;
  69
  70 static struct write_info *child_writes = NULL;
  71 static unsigned int child_writes_num = 0;
  72
  73 static struct fd_orig *fd_orig = NULL;
  74 static unsigned int fd_orig_num = 0;
  75
  76 static pid_t lock_owner;
  77 static struct lock_info *locks = NULL;
  78 static unsigned int lock_num = 0;
  79
  80 static const char info_to_arg[] = "mceoprwf";
  81
  82 /* Dummy call used for failtest_undo wrappers. */
  83 static struct failtest_call unrecorded_call;
  84
  85 static struct failtest_call *add_history_(enum failtest_call_type type,
  86                                           const char *file,
  87                                           unsigned int line,
  88                                           const void *elem,
  89                                           size_t elem_size)
  90 {
  91         /* NULL file is how we suppress failure. */
  92         if (!file)
  93                 return &unrecorded_call;
  94
  95         history = realloc(history, (history_num + 1) * sizeof(*history));
  96         history[history_num].type = type;
  97         history[history_num].file = file;
  98         history[history_num].line = line;
  99         memcpy(&history[history_num].u, elem, elem_size);
 100         return &history[history_num++];
 101 }
 102
 103 #define add_history(type, file, line, elem) \
 104         add_history_((type), (file), (line), (elem), sizeof(*(elem)))
 105
 106 static void save_fd_orig(int fd)
 107 {
 108         unsigned int i;
 109
 110         for (i = 0; i < fd_orig_num; i++)
 111                 if (fd_orig[i].fd == fd)
 112                         return;
 113
 114         fd_orig = realloc(fd_orig, (fd_orig_num + 1) * sizeof(*fd_orig));
 115         fd_orig[fd_orig_num].fd = fd;
 116         fd_orig[fd_orig_num].dupped = false;
 117         fd_orig[fd_orig_num].offset = lseek(fd, 0, SEEK_CUR);
 118         fd_orig[fd_orig_num].size = lseek(fd, 0, SEEK_END);
 119         lseek(fd, fd_orig[fd_orig_num].offset, SEEK_SET);
 120         fd_orig_num++;
 121 }
 122
 123 bool failtest_default_hook(struct failtest_call *history, unsigned num)
 124 {
 125         return true;
 126 }
 127
 128 static bool read_write_info(int fd)
 129 {
 130         struct write_info_hdr hdr;
 131
 132         if (!read_all(fd, &hdr, sizeof(hdr)))
 133                 return false;
 134
 135         child_writes = realloc(child_writes,
 136                                (child_writes_num+1) * sizeof(child_writes[0]));
 137         child_writes[child_writes_num].hdr = hdr;
 138         child_writes[child_writes_num].data = malloc(hdr.len);
 139         if (!read_all(fd, child_writes[child_writes_num].data, hdr.len))
 140                 return false;
 141
 142         child_writes_num++;
 143         return true;
 144 }
 145
 146 static void print_reproduce(void)
 147 {
 148         unsigned int i;
 149
 150         printf("To reproduce: --failpath=");
 151         for (i = 0; i < history_num; i++) {
 152                 if (history[i].fail)
 153                         printf("%c", toupper(info_to_arg[history[i].type]));
 154                 else
 155                         printf("%c", info_to_arg[history[i].type]);
 156         }
 157         printf("\n");
 158 }
 159
 160 static void tell_parent(enum info_type type)
 161 {
 162         if (control_fd != -1)
 163                 write_all(control_fd, &type, sizeof(type));
 164 }
 165
 166 static void child_fail(const char *out, size_t outlen, const char *fmt, ...)
 167 {
 168         va_list ap;
 169
 170         va_start(ap, fmt);
 171         vfprintf(stderr, fmt, ap);
 172         va_end(ap);
 173
 174         fprintf(stderr, "%.*s", (int)outlen, out);
 175         print_reproduce();
 176         tell_parent(FAILURE);
 177         exit(1);
 178 }
 179
 180 static pid_t child;
 181
 182 static void hand_down(int signal)
 183 {
 184         kill(child, signal);
 185 }
 186
 187 static void release_locks(void)
 188 {
 189         /* Locks were never acquired/reacquired? */
 190         if (lock_owner == 0)
 191                 return;
 192
 193         /* We own them?  Release them all. */
 194         if (lock_owner == getpid()) {
 195                 unsigned int i;
 196                 struct flock fl;
 197                 fl.l_type = F_UNLCK;
 198                 fl.l_whence = SEEK_SET;
 199                 fl.l_start = 0;
 200                 fl.l_len = 0;
 201
 202                 for (i = 0; i < lock_num; i++)
 203                         fcntl(locks[i].fd, F_SETLK, &fl);
 204         } else {
 205                 /* Our parent must have them; pass request up. */
 206                 enum info_type type = RELEASE_LOCKS;
 207                 assert(control_fd != -1);
 208                 write_all(control_fd, &type, sizeof(type));
 209         }
 210         lock_owner = 0;
 211 }
 212
 213 /* off_t is a signed type.  Getting its max is non-trivial. */
 214 static off_t off_max(void)
 215 {
 216         BUILD_ASSERT(sizeof(off_t) == 4 || sizeof(off_t) == 8);
 217         if (sizeof(off_t) == 4)
 218                 return (off_t)0x7FFFFFF;
 219         else
 220                 return (off_t)0x7FFFFFFFFFFFFFFULL;
 221 }
 222
 223 static void get_locks(void)
 224 {
 225         unsigned int i;
 226         struct flock fl;
 227
 228         if (lock_owner == getpid())
 229                 return;
 230
 231         if (lock_owner != 0) {
 232                 enum info_type type = RELEASE_LOCKS;
 233                 assert(control_fd != -1);
 234                 write_all(control_fd, &type, sizeof(type));
 235         }
 236
 237         fl.l_whence = SEEK_SET;
 238
 239         for (i = 0; i < lock_num; i++) {
 240                 fl.l_type = locks[i].type;
 241                 fl.l_start = locks[i].start;
 242                 if (locks[i].end == off_max())
 243                         fl.l_len = 0;
 244                 else
 245                         fl.l_len = locks[i].end - locks[i].start + 1;
 246
 247                 if (fcntl(locks[i].fd, F_SETLKW, &fl) != 0)
 248                         abort();
 249         }
 250         lock_owner = getpid();
 251 }
 252
 253 static bool should_fail(struct failtest_call *call)
 254 {
 255         int status;
 256         int control[2], output[2];
 257         enum info_type type = UNEXPECTED;
 258         char *out = NULL;
 259         size_t outlen = 0;
 260
 261         if (call == &unrecorded_call)
 262                 return false;
 263
 264         if (failpath) {
 265                 if (tolower(*failpath) != info_to_arg[call->type])
 266                         errx(1, "Failpath expected '%c' got '%c'\n",
 267                              info_to_arg[call->type], *failpath);
 268                 return isupper(*(failpath++));
 269         }
 270
 271         if (!failtest_hook(history, history_num)) {
 272                 call->fail = false;
 273                 return false;
 274         }
 275
 276         /* We're going to fail in the child. */
 277         call->fail = true;
 278         if (pipe(control) != 0 || pipe(output) != 0)
 279                 err(1, "opening pipe");
 280
 281         /* Prevent double-printing (in child and parent) */
 282         fflush(stdout);
 283         child = fork();
 284         if (child == -1)
 285                 err(1, "forking failed");
 286
 287         if (child == 0) {
 288                 close(control[0]);
 289                 close(output[0]);
 290                 dup2(output[1], STDOUT_FILENO);
 291                 dup2(output[1], STDERR_FILENO);
 292                 if (output[1] != STDOUT_FILENO && output[1] != STDERR_FILENO)
 293                         close(output[1]);
 294                 control_fd = control[1];
 295                 return true;
 296         }
 297
 298         signal(SIGUSR1, hand_down);
 299
 300         close(control[1]);
 301         close(output[1]);
 302
 303         /* We grab output so we can display it; we grab writes so we
 304          * can compare. */
 305         do {
 306                 struct pollfd pfd[2];
 307                 int ret;
 308
 309                 pfd[0].fd = output[0];
 310                 pfd[0].events = POLLIN|POLLHUP;
 311                 pfd[1].fd = control[0];
 312                 pfd[1].events = POLLIN|POLLHUP;
 313
 314                 if (type == SUCCESS)
 315                         ret = poll(pfd, 1, failtest_timeout_ms);
 316                 else
 317                         ret = poll(pfd, 2, failtest_timeout_ms);
 318
 319                 if (ret <= 0)
 320                         hand_down(SIGUSR1);
 321
 322                 if (pfd[0].revents & POLLIN) {
 323                         ssize_t len;
 324
 325                         out = realloc(out, outlen + 8192);
 326                         len = read(output[0], out + outlen, 8192);
 327                         outlen += len;
 328                 } else if (type != SUCCESS && (pfd[1].revents & POLLIN)) {
 329                         if (read_all(control[0], &type, sizeof(type))) {
 330                                 if (type == WRITE) {
 331                                         if (!read_write_info(control[0]))
 332                                                 break;
 333                                 } else if (type == RELEASE_LOCKS) {
 334                                         release_locks();
 335                                         /* FIXME: Tell them we're done... */
 336                                 }
 337                         }
 338                 } else if (pfd[0].revents & POLLHUP) {
 339                         break;
 340                 }
 341         } while (type != FAILURE);
 342
 343         close(output[0]);
 344         close(control[0]);
 345         waitpid(child, &status, 0);
 346         if (!WIFEXITED(status))
 347                 child_fail(out, outlen, "Killed by signal %u: ",
 348                            WTERMSIG(status));
 349         /* Child printed failure already, just pass up exit code. */
 350         if (type == FAILURE) {
 351                 fprintf(stderr, "%.*s", (int)outlen, out);
 352                 tell_parent(type);
 353                 exit(WEXITSTATUS(status) ? WEXITSTATUS(status) : 1);
 354         }
 355         if (WEXITSTATUS(status) != 0)
 356                 child_fail(out, outlen, "Exited with status %i: ",
 357                            WEXITSTATUS(status));
 358
 359         free(out);
 360         signal(SIGUSR1, SIG_DFL);
 361
 362         /* We continue onwards without failing. */
 363         call->fail = false;
 364         return false;
 365 }
 366
 367 void *failtest_calloc(size_t nmemb, size_t size,
 368                       const char *file, unsigned line)
 369 {
 370         struct failtest_call *p;
 371         struct calloc_call call;
 372         call.nmemb = nmemb;
 373         call.size = size;
 374         p = add_history(FAILTEST_CALLOC, file, line, &call);
 375
 376         if (should_fail(p)) {
 377                 p->u.calloc.ret = NULL;
 378                 p->error = ENOMEM;
 379         } else {
 380                 p->u.calloc.ret = calloc(nmemb, size);
 381         }
 382         errno = p->error;
 383         return p->u.calloc.ret;
 384 }
 385
 386 void *failtest_malloc(size_t size, const char *file, unsigned line)
 387 {
 388         struct failtest_call *p;
 389         struct malloc_call call;
 390         call.size = size;
 391
 392         p = add_history(FAILTEST_MALLOC, file, line, &call);
 393         if (should_fail(p)) {
 394                 p->u.calloc.ret = NULL;
 395                 p->error = ENOMEM;
 396         } else {
 397                 p->u.calloc.ret = malloc(size);
 398         }
 399         errno = p->error;
 400         return p->u.calloc.ret;
 401 }
 402
 403 void *failtest_realloc(void *ptr, size_t size, const char *file, unsigned line)
 404 {
 405         struct failtest_call *p;
 406         struct realloc_call call;
 407         call.size = size;
 408         p = add_history(FAILTEST_REALLOC, file, line, &call);
 409
 410         /* FIXME: Try one child moving allocation, one not. */
 411         if (should_fail(p)) {
 412                 p->u.realloc.ret = NULL;
 413                 p->error = ENOMEM;
 414         } else {
 415                 p->u.realloc.ret = realloc(ptr, size);
 416         }
 417         errno = p->error;
 418         return p->u.realloc.ret;
 419 }
 420
 421 int failtest_open(const char *pathname,
 422                   const char *file, unsigned line, ...)
 423 {
 424         struct failtest_call *p;
 425         struct open_call call;
 426         va_list ap;
 427
 428         call.pathname = strdup(pathname);
 429         va_start(ap, line);
 430         call.flags = va_arg(ap, int);
 431         if (call.flags & O_CREAT) {
 432                 call.mode = va_arg(ap, mode_t);
 433                 va_end(ap);
 434         }
 435         p = add_history(FAILTEST_OPEN, file, line, &call);
 436         /* Avoid memory leak! */
 437         if (p == &unrecorded_call)
 438                 free((char *)call.pathname);
 439         if (should_fail(p)) {
 440                 p->u.open.ret = -1;
 441                 /* FIXME: Play with error codes? */
 442                 p->error = EACCES;
 443         } else {
 444                 p->u.open.ret = open(pathname, call.flags, call.mode);
 445         }
 446         errno = p->error;
 447         return p->u.open.ret;
 448 }
 449
 450 int failtest_pipe(int pipefd[2], const char *file, unsigned line)
 451 {
 452         struct failtest_call *p;
 453         struct pipe_call call;
 454
 455         p = add_history(FAILTEST_PIPE, file, line, &call);
 456         if (should_fail(p)) {
 457                 p->u.open.ret = -1;
 458                 /* FIXME: Play with error codes? */
 459                 p->error = EMFILE;
 460         } else {
 461                 p->u.pipe.ret = pipe(p->u.pipe.fds);
 462         }
 463         /* This causes valgrind to notice if they use pipefd[] after failure */
 464         memcpy(pipefd, p->u.pipe.fds, sizeof(p->u.pipe.fds));
 465         errno = p->error;
 466         return p->u.pipe.ret;
 467 }
 468
 469 ssize_t failtest_pread(int fd, void *buf, size_t count, off_t off,
 470                        const char *file, unsigned line)
 471 {
 472         struct failtest_call *p;
 473         struct read_call call;
 474         call.fd = fd;
 475         call.buf = buf;
 476         call.count = count;
 477         call.off = off;
 478         p = add_history(FAILTEST_READ, file, line, &call);
 479
 480         /* This is going to change seek offset, so save it. */
 481         if (control_fd != -1)
 482                 save_fd_orig(fd);
 483
 484         /* FIXME: Try partial read returns. */
 485         if (should_fail(p)) {
 486                 p->u.read.ret = -1;
 487                 p->error = EIO;
 488         } else {
 489                 p->u.read.ret = pread(fd, buf, count, off);
 490         }
 491         errno = p->error;
 492         return p->u.read.ret;
 493 }
 494
 495 static struct write_info *new_write(void)
 496 {
 497         writes = realloc(writes, (writes_num + 1) * sizeof(*writes));
 498         return &writes[writes_num++];
 499 }
 500
 501 ssize_t failtest_pwrite(int fd, const void *buf, size_t count, off_t off,
 502                         const char *file, unsigned line)
 503 {
 504         struct failtest_call *p;
 505         struct write_call call;
 506         off_t offset;
 507
 508         call.fd = fd;
 509         call.buf = buf;
 510         call.count = count;
 511         call.off = off;
 512         p = add_history(FAILTEST_WRITE, file, line, &call);
 513
 514         offset = lseek(fd, 0, SEEK_CUR);
 515
 516         /* If we're a child, save contents and tell parent about write. */
 517         if (control_fd != -1) {
 518                 struct write_info *winfo = new_write();
 519                 enum info_type type = WRITE;
 520
 521                 save_fd_orig(fd);
 522
 523                 winfo->hdr.len = count;
 524                 winfo->hdr.fd = fd;
 525                 winfo->data = malloc(count);
 526                 memcpy(winfo->data, buf, count);
 527                 winfo->hdr.offset = offset;
 528                 if (winfo->hdr.offset != (off_t)-1) {
 529                         lseek(fd, offset, SEEK_SET);
 530                         winfo->olddata = malloc(count);
 531                         winfo->oldlen = read(fd, winfo->olddata, count);
 532                         if (winfo->oldlen == -1)
 533                                 winfo->oldlen = 0;
 534                 }
 535                 write_all(control_fd, &type, sizeof(type));
 536                 write_all(control_fd, &winfo->hdr, sizeof(winfo->hdr));
 537                 write_all(control_fd, winfo->data, count);
 538         }
 539
 540         /* FIXME: Try partial write returns. */
 541         if (should_fail(p)) {
 542                 p->u.write.ret = -1;
 543                 p->error = EIO;
 544         } else {
 545                 /* FIXME: We assume same write order in parent and child */
 546                 if (child_writes_num != 0) {
 547                         if (child_writes[0].hdr.fd != fd)
 548                                 errx(1, "Child wrote to fd %u, not %u?",
 549                                      child_writes[0].hdr.fd, fd);
 550                         if (child_writes[0].hdr.offset != offset)
 551                                 errx(1, "Child wrote to offset %zu, not %zu?",
 552                                      (size_t)child_writes[0].hdr.offset,
 553                                      (size_t)offset);
 554                         if (child_writes[0].hdr.len != count)
 555                                 errx(1, "Child wrote length %zu, not %zu?",
 556                                      child_writes[0].hdr.len, count);
 557                         if (memcmp(child_writes[0].data, buf, count)) {
 558                                 child_fail(NULL, 0,
 559                                            "Child wrote differently to"
 560                                            " fd %u than we did!\n", fd);
 561                         }
 562                         free(child_writes[0].data);
 563                         child_writes_num--;
 564                         memmove(&child_writes[0], &child_writes[1],
 565                                 sizeof(child_writes[0]) * child_writes_num);
 566
 567                         /* Is this is a socket or pipe, child wrote it
 568                            already. */
 569                         if (offset == (off_t)-1) {
 570                                 p->u.write.ret = count;
 571                                 errno = p->error;
 572                                 return p->u.write.ret;
 573                         }
 574                 }
 575                 p->u.write.ret = pwrite(fd, buf, count, off);
 576         }
 577         errno = p->error;
 578         return p->u.write.ret;
 579 }
 580
 581 ssize_t failtest_read(int fd, void *buf, size_t count,
 582                       const char *file, unsigned line)
 583 {
 584         return failtest_pread(fd, buf, count, lseek(fd, 0, SEEK_CUR),
 585                               file, line);
 586 }
 587
 588 ssize_t failtest_write(int fd, const void *buf, size_t count,
 589                        const char *file, unsigned line)
 590 {
 591         return failtest_pwrite(fd, buf, count, lseek(fd, 0, SEEK_CUR),
 592                                file, line);
 593 }
 594
 595 static struct lock_info *WARN_UNUSED_RESULT
 596 add_lock(struct lock_info *locks, int fd, off_t start, off_t end, int type)
 597 {
 598         unsigned int i;
 599         struct lock_info *l;
 600
 601         for (i = 0; i < lock_num; i++) {
 602                 l = &locks[i];
 603
 604                 if (l->fd != fd)
 605                         continue;
 606                 /* Four cases we care about:
 607                  * Start overlap:
 608                  *      l =    |      |
 609                  *      new = |   |
 610                  * Mid overlap:
 611                  *      l =    |      |
 612                  *      new =    |  |
 613                  * End overlap:
 614                  *      l =    |      |
 615                  *      new =      |    |
 616                  * Total overlap:
 617                  *      l =    |      |
 618                  *      new = |         |
 619                  */
 620                 if (start > l->start && end < l->end) {
 621                         /* Mid overlap: trim entry, add new one. */
 622                         off_t new_start, new_end;
 623                         new_start = end + 1;
 624                         new_end = l->end;
 625                         l->end = start - 1;
 626                         locks = add_lock(locks,
 627                                          fd, new_start, new_end, l->type);
 628                         l = &locks[i];
 629                 } else if (start <= l->start && end >= l->end) {
 630                         /* Total overlap: eliminate entry. */
 631                         l->end = 0;
 632                         l->start = 1;
 633                 } else if (end >= l->start && end < l->end) {
 634                         /* Start overlap: trim entry. */
 635                         l->start = end + 1;
 636                 } else if (start > l->start && start <= l->end) {
 637                         /* End overlap: trim entry. */
 638                         l->end = start-1;
 639                 }
 640                 /* Nothing left?  Remove it. */
 641                 if (l->end < l->start) {
 642                         memmove(l, l + 1, (--lock_num - i) * sizeof(l[0]));
 643                         i--;
 644                 }
 645         }
 646
 647         if (type != F_UNLCK) {
 648                 locks = realloc(locks, (lock_num + 1) * sizeof(*locks));
 649                 l = &locks[lock_num++];
 650                 l->fd = fd;
 651                 l->start = start;
 652                 l->end = end;
 653                 l->type = type;
 654         }
 655         return locks;
 656 }
 657
 658 /* We only trap this so we can dup fds in case we need to restore. */
 659 int failtest_close(int fd)
 660 {
 661         unsigned int i;
 662         int newfd = -1;
 663
 664         for (i = 0; i < fd_orig_num; i++) {
 665                 if (fd_orig[i].fd == fd) {
 666                         fd_orig[i].fd = newfd = dup(fd);
 667                         fd_orig[i].dupped = true;
 668                 }
 669         }
 670
 671         for (i = 0; i < writes_num; i++) {
 672                 if (writes[i].hdr.fd == fd)
 673                         writes[i].hdr.fd = newfd;
 674         }
 675
 676         locks = add_lock(locks, fd, 0, off_max(), F_UNLCK);
 677         return close(fd);
 678 }
 679
 680 /* Zero length means "to end of file" */
 681 static off_t end_of(off_t start, off_t len)
 682 {
 683         if (len == 0)
 684                 return off_max();
 685         return start + len - 1;
 686 }
 687
 688 /* FIXME: This only handles locks, really. */
 689 int failtest_fcntl(int fd, const char *file, unsigned line, int cmd, ...)
 690 {
 691         struct failtest_call *p;
 692         struct fcntl_call call;
 693         va_list ap;
 694
 695         call.fd = fd;
 696         call.cmd = cmd;
 697
 698         /* Argument extraction. */
 699         switch (cmd) {
 700         case F_SETFL:
 701         case F_SETFD:
 702                 va_start(ap, cmd);
 703                 call.arg.l = va_arg(ap, long);
 704                 va_end(ap);
 705                 return fcntl(fd, cmd, call.arg.l);
 706         case F_GETFD:
 707         case F_GETFL:
 708                 return fcntl(fd, cmd);
 709         case F_GETLK:
 710                 get_locks();
 711                 va_start(ap, cmd);
 712                 call.arg.fl = *va_arg(ap, struct flock *);
 713                 va_end(ap);
 714                 return fcntl(fd, cmd, &call.arg.fl);
 715         case F_SETLK:
 716         case F_SETLKW:
 717                 va_start(ap, cmd);
 718                 call.arg.fl = *va_arg(ap, struct flock *);
 719                 va_end(ap);
 720                 break;
 721         default:
 722                 /* This means you need to implement it here. */
 723                 err(1, "failtest: unknown fcntl %u", cmd);
 724         }
 725
 726         p = add_history(FAILTEST_FCNTL, file, line, &call);
 727         get_locks();
 728
 729         if (should_fail(p)) {
 730                 p->u.fcntl.ret = -1;
 731                 if (p->u.fcntl.cmd == F_SETLK)
 732                         p->error = EAGAIN;
 733                 else
 734                         p->error = EDEADLK;
 735         } else {
 736                 p->u.fcntl.ret = fcntl(p->u.fcntl.fd, p->u.fcntl.cmd,
 737                                        &p->u.fcntl.arg.fl);
 738                 if (p->u.fcntl.ret == -1)
 739                         p->error = errno;
 740                 else {
 741                         /* We don't handle anything else yet. */
 742                         assert(p->u.fcntl.arg.fl.l_whence == SEEK_SET);
 743                         locks = add_lock(locks,
 744                                          p->u.fcntl.fd,
 745                                          p->u.fcntl.arg.fl.l_start,
 746                                          end_of(p->u.fcntl.arg.fl.l_start,
 747                                                 p->u.fcntl.arg.fl.l_len),
 748                                          p->u.fcntl.arg.fl.l_type);
 749                 }
 750         }
 751         errno = p->error;
 752         return p->u.fcntl.ret;
 753 }
 754
 755 void failtest_init(int argc, char *argv[])
 756 {
 757         if (argc == 2
 758             && strncmp(argv[1], "--failpath=", strlen("--failpath=")) == 0) {
 759                 failpath = argv[1] + strlen("--failpath=");
 760         }
 761 }
 762
 763 /* Free up memory, so valgrind doesn't report leaks. */
 764 static void free_everything(void)
 765 {
 766         unsigned int i;
 767
 768         for (i = 0; i < writes_num; i++) {
 769                 free(writes[i].data);
 770                 if (writes[i].hdr.offset != (off_t)-1)
 771                         free(writes[i].olddata);
 772         }
 773         free(writes);
 774         free(fd_orig);
 775         for (i = 0; i < history_num; i++) {
 776                 if (history[i].type == FAILTEST_OPEN)
 777                         free((char *)history[i].u.open.pathname);
 778         }
 779         free(history);
 780 }
 781
 782 void failtest_exit(int status)
 783 {
 784         unsigned int i;
 785
 786         if (control_fd == -1) {
 787                 free_everything();
 788                 exit(status);
 789         }
 790
 791         if (failtest_exit_check) {
 792                 if (!failtest_exit_check(history, history_num))
 793                         child_fail(NULL, 0, "failtest_exit_check failed\n");
 794         }
 795
 796         /* Restore any stuff we overwrote. */
 797         for (i = 0; i < writes_num; i++) {
 798                 if (writes[i].hdr.offset == (off_t)-1)
 799                         continue;
 800                 if (writes[i].oldlen != 0) {
 801                         lseek(writes[i].hdr.fd, writes[i].hdr.offset,
 802                               SEEK_SET);
 803                         write(writes[i].hdr.fd, writes[i].olddata,
 804                               writes[i].oldlen);
 805                 }
 806         }
 807
 808         /* Fix up fd offsets, restore sizes. */
 809         for (i = 0; i < fd_orig_num; i++) {
 810                 lseek(fd_orig[i].fd, fd_orig[i].offset, SEEK_SET);
 811                 ftruncate(fd_orig[i].fd, fd_orig[i].size);
 812                 /* Free up any file descriptors we dup'ed. */
 813                 if (fd_orig[i].dupped)
 814                         close(fd_orig[i].fd);
 815         }
 816
 817         free_everything();
 818         tell_parent(SUCCESS);
 819         exit(0);
 820 }