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
  29 enum info_type {
  30         WRITE,
  31         RELEASE_LOCKS,
  32         FAILURE,
  33         SUCCESS,
  34         UNEXPECTED
  35 };
  36
  37 struct lock_info {
  38         int fd;
  39         /* end is inclusive: you can't have a 0-byte lock. */
  40         off_t start, end;
  41         int type;
  42 };
  43
  44 bool (*failtest_exit_check)(struct failtest_call *history, unsigned num);
  45
  46 static struct failtest_call *history = NULL;
  47 static unsigned int history_num = 0;
  48 static int control_fd = -1;
  49 static struct timeval start;
  50
  51 static struct write_call *child_writes = NULL;
  52 static unsigned int child_writes_num = 0;
  53
  54 static pid_t lock_owner;
  55 static struct lock_info *locks = NULL;
  56 static unsigned int lock_num = 0;
  57
  58 static const char info_to_arg[] = "mceoprwf";
  59
  60 /* Dummy call used for failtest_undo wrappers. */
  61 static struct failtest_call unrecorded_call;
  62
  63 static struct failtest_call *add_history_(enum failtest_call_type type,
  64                                           const char *file,
  65                                           unsigned int line,
  66                                           const void *elem,
  67                                           size_t elem_size)
  68 {
  69         /* NULL file is how we suppress failure. */
  70         if (!file)
  71                 return &unrecorded_call;
  72
  73         history = realloc(history, (history_num + 1) * sizeof(*history));
  74         history[history_num].type = type;
  75         history[history_num].file = file;
  76         history[history_num].line = line;
  77         history[history_num].cleanup = NULL;
  78         memcpy(&history[history_num].u, elem, elem_size);
  79         return &history[history_num++];
  80 }
  81
  82 #define add_history(type, file, line, elem) \
  83         add_history_((type), (file), (line), (elem), sizeof(*(elem)))
  84
  85 #define set_cleanup(call, clean, type)                  \
  86         (call)->cleanup = (void *)((void)sizeof(clean((type *)NULL)), (clean))
  87
  88 bool failtest_default_hook(struct failtest_call *history, unsigned num)
  89 {
  90         return true;
  91 }
  92
  93 static bool read_write_info(int fd)
  94 {
  95         struct write_call *w;
  96         char *buf;
  97
  98         /* We don't need all of this, but it's simple. */
  99         child_writes = realloc(child_writes,
 100                                (child_writes_num+1) * sizeof(child_writes[0]));
 101         w = &child_writes[child_writes_num];
 102         if (!read_all(fd, w, sizeof(*w)))
 103                 return false;
 104
 105         w->buf = buf = malloc(w->count);
 106         if (!read_all(fd, buf, w->count))
 107                 return false;
 108
 109         child_writes_num++;
 110         return true;
 111 }
 112
 113 static char *failpath_string(void)
 114 {
 115         unsigned int i;
 116         char *ret = malloc(history_num + 1);
 117
 118         for (i = 0; i < history_num; i++) {
 119                 ret[i] = info_to_arg[history[i].type];
 120                 if (history[i].fail)
 121                         ret[i] = toupper(ret[i]);
 122         }
 123         ret[i] = '\0';
 124         return ret;
 125 }
 126
 127 static void tell_parent(enum info_type type)
 128 {
 129         if (control_fd != -1)
 130                 write_all(control_fd, &type, sizeof(type));
 131 }
 132
 133 static void child_fail(const char *out, size_t outlen, const char *fmt, ...)
 134 {
 135         va_list ap;
 136         char *path = failpath_string();
 137
 138         va_start(ap, fmt);
 139         vfprintf(stderr, fmt, ap);
 140         va_end(ap);
 141
 142         fprintf(stderr, "%.*s", (int)outlen, out);
 143         printf("To reproduce: --failpath=%s\n", path);
 144         free(path);
 145         tell_parent(FAILURE);
 146         exit(1);
 147 }
 148
 149 static pid_t child;
 150
 151 static void hand_down(int signal)
 152 {
 153         kill(child, signal);
 154 }
 155
 156 static void release_locks(void)
 157 {
 158         /* Locks were never acquired/reacquired? */
 159         if (lock_owner == 0)
 160                 return;
 161
 162         /* We own them?  Release them all. */
 163         if (lock_owner == getpid()) {
 164                 unsigned int i;
 165                 struct flock fl;
 166                 fl.l_type = F_UNLCK;
 167                 fl.l_whence = SEEK_SET;
 168                 fl.l_start = 0;
 169                 fl.l_len = 0;
 170
 171                 for (i = 0; i < lock_num; i++)
 172                         fcntl(locks[i].fd, F_SETLK, &fl);
 173         } else {
 174                 /* Our parent must have them; pass request up. */
 175                 enum info_type type = RELEASE_LOCKS;
 176                 assert(control_fd != -1);
 177                 write_all(control_fd, &type, sizeof(type));
 178         }
 179         lock_owner = 0;
 180 }
 181
 182 /* off_t is a signed type.  Getting its max is non-trivial. */
 183 static off_t off_max(void)
 184 {
 185         BUILD_ASSERT(sizeof(off_t) == 4 || sizeof(off_t) == 8);
 186         if (sizeof(off_t) == 4)
 187                 return (off_t)0x7FFFFFF;
 188         else
 189                 return (off_t)0x7FFFFFFFFFFFFFFULL;
 190 }
 191
 192 static void get_locks(void)
 193 {
 194         unsigned int i;
 195         struct flock fl;
 196
 197         if (lock_owner == getpid())
 198                 return;
 199
 200         if (lock_owner != 0) {
 201                 enum info_type type = RELEASE_LOCKS;
 202                 assert(control_fd != -1);
 203                 write_all(control_fd, &type, sizeof(type));
 204         }
 205
 206         fl.l_whence = SEEK_SET;
 207
 208         for (i = 0; i < lock_num; i++) {
 209                 fl.l_type = locks[i].type;
 210                 fl.l_start = locks[i].start;
 211                 if (locks[i].end == off_max())
 212                         fl.l_len = 0;
 213                 else
 214                         fl.l_len = locks[i].end - locks[i].start + 1;
 215
 216                 if (fcntl(locks[i].fd, F_SETLKW, &fl) != 0)
 217                         abort();
 218         }
 219         lock_owner = getpid();
 220 }
 221
 222 static void trace_str(const char *str)
 223 {
 224         ssize_t ret;
 225
 226         while ((ret = write(tracefd, str, strlen(str))) <= 0) {
 227                 str += ret;
 228                 if (!*str)
 229                         return;
 230         }
 231         err(1, "Writing trace.");
 232 }
 233
 234 struct saved_file {
 235         struct saved_file *next;
 236         int fd;
 237         void *contents;
 238         off_t off, len;
 239 };
 240
 241 static struct saved_file *save_file(struct saved_file *next, int fd)
 242 {
 243         struct saved_file *s = malloc(sizeof(*s));
 244
 245         s->next = next;
 246         s->fd = fd;
 247         s->off = lseek(fd, 0, SEEK_CUR);
 248         /* Special file?  Erk... */
 249         assert(s->off != -1);
 250         s->len = lseek(fd, 0, SEEK_END);
 251         lseek(fd, 0, SEEK_SET);
 252         s->contents = malloc(s->len);
 253         read(fd, s->contents, s->len);
 254         lseek(fd, s->off, SEEK_SET);
 255         return s;
 256 }
 257
 258 /* We have little choice but to save and restore open files: mmap means we
 259  * can really intercept changes in the child.
 260  *
 261  * We could do non-mmap'ed files on demand, however. */
 262 static struct saved_file *save_files(void)
 263 {
 264         struct saved_file *files = NULL;
 265         int i;
 266
 267         /* Figure out the set of live fds. */
 268         for (i = history_num - 2; i >= 0; i--) {
 269                 if (history[i].type == FAILTEST_OPEN) {
 270                         int fd = history[i].u.open.ret;
 271                         /* Only do successful, writable fds. */
 272                         if (fd < 0)
 273                                 continue;
 274
 275                         /* If it was closed, cleanup == NULL. */
 276                         if (!history[i].cleanup)
 277                                 continue;
 278
 279                         if ((history[i].u.open.flags & O_RDWR) == O_RDWR) {
 280                                 files = save_file(files, fd);
 281                         } else if ((history[i].u.open.flags & O_WRONLY)
 282                                    == O_WRONLY) {
 283                                 /* FIXME: Handle O_WRONLY.  Open with O_RDWR? */
 284                                 abort();
 285                         }
 286                 }
 287         }
 288
 289         return files;
 290 }
 291
 292 static void restore_files(struct saved_file *s)
 293 {
 294         while (s) {
 295                 struct saved_file *next = s->next;
 296
 297                 lseek(s->fd, 0, SEEK_SET);
 298                 write(s->fd, s->contents, s->len);
 299                 ftruncate(s->fd, s->len);
 300                 free(s->contents);
 301                 lseek(s->fd, s->off, SEEK_SET);
 302                 free(s);
 303                 s = next;
 304         }
 305 }
 306
 307 static bool should_fail(struct failtest_call *call)
 308 {
 309         int status;
 310         int control[2], output[2];
 311         enum info_type type = UNEXPECTED;
 312         char *out = NULL;
 313         size_t outlen = 0;
 314         struct saved_file *files;
 315
 316         if (call == &unrecorded_call)
 317                 return false;
 318
 319         if (failpath) {
 320                 /* + means continue after end, like normal. */
 321                 if (*failpath == '+')
 322                         failpath = NULL;
 323                 else {
 324                         if (tolower(*failpath) != info_to_arg[call->type])
 325                                 errx(1, "Failpath expected '%c' got '%c'\n",
 326                                      info_to_arg[call->type], *failpath);
 327                         call->fail = isupper(*(failpath++));
 328                         return call->fail;
 329                 }
 330         }
 331
 332         if (!failtest_hook(history, history_num)) {
 333                 call->fail = false;
 334                 return false;
 335         }
 336
 337         files = save_files();
 338
 339         /* We're going to fail in the child. */
 340         call->fail = true;
 341         if (pipe(control) != 0 || pipe(output) != 0)
 342                 err(1, "opening pipe");
 343
 344         /* Prevent double-printing (in child and parent) */
 345         fflush(stdout);
 346         child = fork();
 347         if (child == -1)
 348                 err(1, "forking failed");
 349
 350         if (child == 0) {
 351                 if (tracefd != -1) {
 352                         struct timeval now;
 353                         char str[50], *p;
 354                         gettimeofday(&now, NULL);
 355                         if (now.tv_usec < start.tv_usec) {
 356                                 now.tv_sec--;
 357                                 now.tv_usec += 1000000;
 358                         }
 359                         now.tv_usec -= start.tv_usec;
 360                         now.tv_sec -= start.tv_sec;
 361                         sprintf(str, "%u (%u.%02u): ", getpid(),
 362                                 (int)now.tv_sec, (int)now.tv_usec / 10000);
 363                         trace_str(str);
 364                         p = failpath_string();
 365                         trace_str(p);
 366                         free(p);
 367                         trace_str("(");
 368                         p = strchr(history[history_num-1].file, '/');
 369                         if (p)
 370                                 trace_str(p+1);
 371                         else
 372                                 trace_str(history[history_num-1].file);
 373                         sprintf(str, ":%u)\n", history[history_num-1].line);
 374                         trace_str(str);
 375                 }
 376                 close(control[0]);
 377                 close(output[0]);
 378                 dup2(output[1], STDOUT_FILENO);
 379                 dup2(output[1], STDERR_FILENO);
 380                 if (output[1] != STDOUT_FILENO && output[1] != STDERR_FILENO)
 381                         close(output[1]);
 382                 control_fd = control[1];
 383                 return true;
 384         }
 385
 386         signal(SIGUSR1, hand_down);
 387
 388         close(control[1]);
 389         close(output[1]);
 390
 391         /* We grab output so we can display it; we grab writes so we
 392          * can compare. */
 393         do {
 394                 struct pollfd pfd[2];
 395                 int ret;
 396
 397                 pfd[0].fd = output[0];
 398                 pfd[0].events = POLLIN|POLLHUP;
 399                 pfd[1].fd = control[0];
 400                 pfd[1].events = POLLIN|POLLHUP;
 401
 402                 if (type == SUCCESS)
 403                         ret = poll(pfd, 1, failtest_timeout_ms);
 404                 else
 405                         ret = poll(pfd, 2, failtest_timeout_ms);
 406
 407                 if (ret <= 0)
 408                         hand_down(SIGUSR1);
 409
 410                 if (pfd[0].revents & POLLIN) {
 411                         ssize_t len;
 412
 413                         out = realloc(out, outlen + 8192);
 414                         len = read(output[0], out + outlen, 8192);
 415                         outlen += len;
 416                 } else if (type != SUCCESS && (pfd[1].revents & POLLIN)) {
 417                         if (read_all(control[0], &type, sizeof(type))) {
 418                                 if (type == WRITE) {
 419                                         if (!read_write_info(control[0]))
 420                                                 break;
 421                                 } else if (type == RELEASE_LOCKS) {
 422                                         release_locks();
 423                                         /* FIXME: Tell them we're done... */
 424                                 }
 425                         }
 426                 } else if (pfd[0].revents & POLLHUP) {
 427                         break;
 428                 }
 429         } while (type != FAILURE);
 430
 431         close(output[0]);
 432         close(control[0]);
 433         waitpid(child, &status, 0);
 434         if (!WIFEXITED(status))
 435                 child_fail(out, outlen, "Killed by signal %u: ",
 436                            WTERMSIG(status));
 437         /* Child printed failure already, just pass up exit code. */
 438         if (type == FAILURE) {
 439                 fprintf(stderr, "%.*s", (int)outlen, out);
 440                 tell_parent(type);
 441                 exit(WEXITSTATUS(status) ? WEXITSTATUS(status) : 1);
 442         }
 443         if (WEXITSTATUS(status) != 0)
 444                 child_fail(out, outlen, "Exited with status %i: ",
 445                            WEXITSTATUS(status));
 446
 447         free(out);
 448         signal(SIGUSR1, SIG_DFL);
 449
 450         restore_files(files);
 451
 452         /* We continue onwards without failing. */
 453         call->fail = false;
 454         return false;
 455 }
 456
 457 static void cleanup_calloc(struct calloc_call *call)
 458 {
 459         free(call->ret);
 460 }
 461
 462 void *failtest_calloc(size_t nmemb, size_t size,
 463                       const char *file, unsigned line)
 464 {
 465         struct failtest_call *p;
 466         struct calloc_call call;
 467         call.nmemb = nmemb;
 468         call.size = size;
 469         p = add_history(FAILTEST_CALLOC, file, line, &call);
 470
 471         if (should_fail(p)) {
 472                 p->u.calloc.ret = NULL;
 473                 p->error = ENOMEM;
 474         } else {
 475                 p->u.calloc.ret = calloc(nmemb, size);
 476                 set_cleanup(p, cleanup_calloc, struct calloc_call);
 477         }
 478         errno = p->error;
 479         return p->u.calloc.ret;
 480 }
 481
 482 static void cleanup_malloc(struct malloc_call *call)
 483 {
 484         free(call->ret);
 485 }
 486
 487 void *failtest_malloc(size_t size, const char *file, unsigned line)
 488 {
 489         struct failtest_call *p;
 490         struct malloc_call call;
 491         call.size = size;
 492
 493         p = add_history(FAILTEST_MALLOC, file, line, &call);
 494         if (should_fail(p)) {
 495                 p->u.calloc.ret = NULL;
 496                 p->error = ENOMEM;
 497         } else {
 498                 p->u.calloc.ret = malloc(size);
 499                 set_cleanup(p, cleanup_malloc, struct malloc_call);
 500         }
 501         errno = p->error;
 502         return p->u.calloc.ret;
 503 }
 504
 505 static void cleanup_realloc(struct realloc_call *call)
 506 {
 507         free(call->ret);
 508 }
 509
 510 /* Walk back and find out if we got this ptr from a previous routine. */
 511 static void fixup_ptr_history(void *ptr, unsigned int last)
 512 {
 513         int i;
 514
 515         /* Start at end of history, work back. */
 516         for (i = last - 1; i >= 0; i--) {
 517                 switch (history[i].type) {
 518                 case FAILTEST_REALLOC:
 519                         if (history[i].u.realloc.ret == ptr) {
 520                                 history[i].cleanup = NULL;
 521                                 return;
 522                         }
 523                         break;
 524                 case FAILTEST_MALLOC:
 525                         if (history[i].u.malloc.ret == ptr) {
 526                                 history[i].cleanup = NULL;
 527                                 return;
 528                         }
 529                         break;
 530                 case FAILTEST_CALLOC:
 531                         if (history[i].u.calloc.ret == ptr) {
 532                                 history[i].cleanup = NULL;
 533                                 return;
 534                         }
 535                         break;
 536                 default:
 537                         break;
 538                 }
 539         }
 540 }
 541
 542 void *failtest_realloc(void *ptr, size_t size, const char *file, unsigned line)
 543 {
 544         struct failtest_call *p;
 545         struct realloc_call call;
 546         call.size = size;
 547         p = add_history(FAILTEST_REALLOC, file, line, &call);
 548
 549         /* FIXME: Try one child moving allocation, one not. */
 550         if (should_fail(p)) {
 551                 p->u.realloc.ret = NULL;
 552                 p->error = ENOMEM;
 553         } else {
 554                 fixup_ptr_history(ptr, history_num-1);
 555                 p->u.realloc.ret = realloc(ptr, size);
 556                 set_cleanup(p, cleanup_realloc, struct realloc_call);
 557         }
 558         errno = p->error;
 559         return p->u.realloc.ret;
 560 }
 561
 562 void failtest_free(void *ptr)
 563 {
 564         fixup_ptr_history(ptr, history_num);
 565         free(ptr);
 566 }
 567
 568 static void cleanup_open(struct open_call *call)
 569 {
 570         close(call->ret);
 571 }
 572
 573 int failtest_open(const char *pathname,
 574                   const char *file, unsigned line, ...)
 575 {
 576         struct failtest_call *p;
 577         struct open_call call;
 578         va_list ap;
 579
 580         call.pathname = strdup(pathname);
 581         va_start(ap, line);
 582         call.flags = va_arg(ap, int);
 583         if (call.flags & O_CREAT) {
 584                 call.mode = va_arg(ap, mode_t);
 585                 va_end(ap);
 586         }
 587         p = add_history(FAILTEST_OPEN, file, line, &call);
 588         /* Avoid memory leak! */
 589         if (p == &unrecorded_call)
 590                 free((char *)call.pathname);
 591         if (should_fail(p)) {
 592                 p->u.open.ret = -1;
 593                 /* FIXME: Play with error codes? */
 594                 p->error = EACCES;
 595         } else {
 596                 p->u.open.ret = open(pathname, call.flags, call.mode);
 597                 set_cleanup(p, cleanup_open, struct open_call);
 598         }
 599         errno = p->error;
 600         return p->u.open.ret;
 601 }
 602
 603 static void cleanup_pipe(struct pipe_call *call)
 604 {
 605         if (!call->closed[0])
 606                 close(call->fds[0]);
 607         if (!call->closed[1])
 608                 close(call->fds[1]);
 609 }
 610
 611 int failtest_pipe(int pipefd[2], const char *file, unsigned line)
 612 {
 613         struct failtest_call *p;
 614         struct pipe_call call;
 615
 616         p = add_history(FAILTEST_PIPE, file, line, &call);
 617         if (should_fail(p)) {
 618                 p->u.open.ret = -1;
 619                 /* FIXME: Play with error codes? */
 620                 p->error = EMFILE;
 621         } else {
 622                 p->u.pipe.ret = pipe(p->u.pipe.fds);
 623                 p->u.pipe.closed[0] = p->u.pipe.closed[1] = false;
 624                 set_cleanup(p, cleanup_pipe, struct pipe_call);
 625         }
 626         /* This causes valgrind to notice if they use pipefd[] after failure */
 627         memcpy(pipefd, p->u.pipe.fds, sizeof(p->u.pipe.fds));
 628         errno = p->error;
 629         return p->u.pipe.ret;
 630 }
 631
 632 ssize_t failtest_pread(int fd, void *buf, size_t count, off_t off,
 633                        const char *file, unsigned line)
 634 {
 635         struct failtest_call *p;
 636         struct read_call call;
 637         call.fd = fd;
 638         call.buf = buf;
 639         call.count = count;
 640         call.off = off;
 641         p = add_history(FAILTEST_READ, file, line, &call);
 642
 643         /* FIXME: Try partial read returns. */
 644         if (should_fail(p)) {
 645                 p->u.read.ret = -1;
 646                 p->error = EIO;
 647         } else {
 648                 p->u.read.ret = pread(fd, buf, count, off);
 649         }
 650         errno = p->error;
 651         return p->u.read.ret;
 652 }
 653
 654 ssize_t failtest_pwrite(int fd, const void *buf, size_t count, off_t off,
 655                         const char *file, unsigned line)
 656 {
 657         struct failtest_call *p;
 658         struct write_call call;
 659
 660         call.fd = fd;
 661         call.buf = buf;
 662         call.count = count;
 663         call.off = off;
 664         p = add_history(FAILTEST_WRITE, file, line, &call);
 665
 666         /* If we're a child, tell parent about write. */
 667         if (control_fd != -1) {
 668                 enum info_type type = WRITE;
 669
 670                 write_all(control_fd, &type, sizeof(type));
 671                 write_all(control_fd, &p->u.write, sizeof(p->u.write));
 672                 write_all(control_fd, buf, count);
 673         }
 674
 675         /* FIXME: Try partial write returns. */
 676         if (should_fail(p)) {
 677                 p->u.write.ret = -1;
 678                 p->error = EIO;
 679         } else {
 680                 /* FIXME: We assume same write order in parent and child */
 681                 if (child_writes_num != 0) {
 682                         if (child_writes[0].fd != fd)
 683                                 errx(1, "Child wrote to fd %u, not %u?",
 684                                      child_writes[0].fd, fd);
 685                         if (child_writes[0].off != p->u.write.off)
 686                                 errx(1, "Child wrote to offset %zu, not %zu?",
 687                                      (size_t)child_writes[0].off,
 688                                      (size_t)p->u.write.off);
 689                         if (child_writes[0].count != count)
 690                                 errx(1, "Child wrote length %zu, not %zu?",
 691                                      child_writes[0].count, count);
 692                         if (memcmp(child_writes[0].buf, buf, count)) {
 693                                 child_fail(NULL, 0,
 694                                            "Child wrote differently to"
 695                                            " fd %u than we did!\n", fd);
 696                         }
 697                         free((char *)child_writes[0].buf);
 698                         child_writes_num--;
 699                         memmove(&child_writes[0], &child_writes[1],
 700                                 sizeof(child_writes[0]) * child_writes_num);
 701
 702                         /* Is this is a socket or pipe, child wrote it
 703                            already. */
 704                         if (p->u.write.off == (off_t)-1) {
 705                                 p->u.write.ret = count;
 706                                 errno = p->error;
 707                                 return p->u.write.ret;
 708                         }
 709                 }
 710                 p->u.write.ret = pwrite(fd, buf, count, off);
 711         }
 712         errno = p->error;
 713         return p->u.write.ret;
 714 }
 715
 716 ssize_t failtest_read(int fd, void *buf, size_t count,
 717                       const char *file, unsigned line)
 718 {
 719         return failtest_pread(fd, buf, count, lseek(fd, 0, SEEK_CUR),
 720                               file, line);
 721 }
 722
 723 ssize_t failtest_write(int fd, const void *buf, size_t count,
 724                        const char *file, unsigned line)
 725 {
 726         return failtest_pwrite(fd, buf, count, lseek(fd, 0, SEEK_CUR),
 727                                file, line);
 728 }
 729
 730 static struct lock_info *WARN_UNUSED_RESULT
 731 add_lock(struct lock_info *locks, int fd, off_t start, off_t end, int type)
 732 {
 733         unsigned int i;
 734         struct lock_info *l;
 735
 736         for (i = 0; i < lock_num; i++) {
 737                 l = &locks[i];
 738
 739                 if (l->fd != fd)
 740                         continue;
 741                 /* Four cases we care about:
 742                  * Start overlap:
 743                  *      l =    |      |
 744                  *      new = |   |
 745                  * Mid overlap:
 746                  *      l =    |      |
 747                  *      new =    |  |
 748                  * End overlap:
 749                  *      l =    |      |
 750                  *      new =      |    |
 751                  * Total overlap:
 752                  *      l =    |      |
 753                  *      new = |         |
 754                  */
 755                 if (start > l->start && end < l->end) {
 756                         /* Mid overlap: trim entry, add new one. */
 757                         off_t new_start, new_end;
 758                         new_start = end + 1;
 759                         new_end = l->end;
 760                         l->end = start - 1;
 761                         locks = add_lock(locks,
 762                                          fd, new_start, new_end, l->type);
 763                         l = &locks[i];
 764                 } else if (start <= l->start && end >= l->end) {
 765                         /* Total overlap: eliminate entry. */
 766                         l->end = 0;
 767                         l->start = 1;
 768                 } else if (end >= l->start && end < l->end) {
 769                         /* Start overlap: trim entry. */
 770                         l->start = end + 1;
 771                 } else if (start > l->start && start <= l->end) {
 772                         /* End overlap: trim entry. */
 773                         l->end = start-1;
 774                 }
 775                 /* Nothing left?  Remove it. */
 776                 if (l->end < l->start) {
 777                         memmove(l, l + 1, (--lock_num - i) * sizeof(l[0]));
 778                         i--;
 779                 }
 780         }
 781
 782         if (type != F_UNLCK) {
 783                 locks = realloc(locks, (lock_num + 1) * sizeof(*locks));
 784                 l = &locks[lock_num++];
 785                 l->fd = fd;
 786                 l->start = start;
 787                 l->end = end;
 788                 l->type = type;
 789         }
 790         return locks;
 791 }
 792
 793 /* We trap this so we can record it: we don't fail it. */
 794 int failtest_close(int fd)
 795 {
 796         int i;
 797
 798         if (fd < 0)
 799                 return close(fd);
 800
 801         /* Trace history to find source of fd. */
 802         for (i = history_num-1; i >= 0; i--) {
 803                 switch (history[i].type) {
 804                 case FAILTEST_PIPE:
 805                         /* From a pipe? */
 806                         if (history[i].u.pipe.fds[0] == fd) {
 807                                 assert(!history[i].u.pipe.closed[0]);
 808                                 history[i].u.pipe.closed[0] = true;
 809                                 if (history[i].u.pipe.closed[1])
 810                                         history[i].cleanup = NULL;
 811                                 goto out;
 812                         }
 813                         if (history[i].u.pipe.fds[1] == fd) {
 814                                 assert(!history[i].u.pipe.closed[1]);
 815                                 history[i].u.pipe.closed[1] = true;
 816                                 if (history[i].u.pipe.closed[0])
 817                                         history[i].cleanup = NULL;
 818                                 goto out;
 819                         }
 820                         break;
 821                 case FAILTEST_OPEN:
 822                         if (history[i].u.open.ret == fd) {
 823                                 assert((void *)history[i].cleanup
 824                                        == (void *)cleanup_open);
 825                                 history[i].cleanup = NULL;
 826                                 goto out;
 827                         }
 828                         break;
 829                 default:
 830                         break;
 831                 }
 832         }
 833
 834 out:
 835         locks = add_lock(locks, fd, 0, off_max(), F_UNLCK);
 836         return close(fd);
 837 }
 838
 839 /* Zero length means "to end of file" */
 840 static off_t end_of(off_t start, off_t len)
 841 {
 842         if (len == 0)
 843                 return off_max();
 844         return start + len - 1;
 845 }
 846
 847 /* FIXME: This only handles locks, really. */
 848 int failtest_fcntl(int fd, const char *file, unsigned line, int cmd, ...)
 849 {
 850         struct failtest_call *p;
 851         struct fcntl_call call;
 852         va_list ap;
 853
 854         call.fd = fd;
 855         call.cmd = cmd;
 856
 857         /* Argument extraction. */
 858         switch (cmd) {
 859         case F_SETFL:
 860         case F_SETFD:
 861                 va_start(ap, cmd);
 862                 call.arg.l = va_arg(ap, long);
 863                 va_end(ap);
 864                 return fcntl(fd, cmd, call.arg.l);
 865         case F_GETFD:
 866         case F_GETFL:
 867                 return fcntl(fd, cmd);
 868         case F_GETLK:
 869                 get_locks();
 870                 va_start(ap, cmd);
 871                 call.arg.fl = *va_arg(ap, struct flock *);
 872                 va_end(ap);
 873                 return fcntl(fd, cmd, &call.arg.fl);
 874         case F_SETLK:
 875         case F_SETLKW:
 876                 va_start(ap, cmd);
 877                 call.arg.fl = *va_arg(ap, struct flock *);
 878                 va_end(ap);
 879                 break;
 880         default:
 881                 /* This means you need to implement it here. */
 882                 err(1, "failtest: unknown fcntl %u", cmd);
 883         }
 884
 885         p = add_history(FAILTEST_FCNTL, file, line, &call);
 886         get_locks();
 887
 888         if (should_fail(p)) {
 889                 p->u.fcntl.ret = -1;
 890                 if (p->u.fcntl.cmd == F_SETLK)
 891                         p->error = EAGAIN;
 892                 else
 893                         p->error = EDEADLK;
 894         } else {
 895                 p->u.fcntl.ret = fcntl(p->u.fcntl.fd, p->u.fcntl.cmd,
 896                                        &p->u.fcntl.arg.fl);
 897                 if (p->u.fcntl.ret == -1)
 898                         p->error = errno;
 899                 else {
 900                         /* We don't handle anything else yet. */
 901                         assert(p->u.fcntl.arg.fl.l_whence == SEEK_SET);
 902                         locks = add_lock(locks,
 903                                          p->u.fcntl.fd,
 904                                          p->u.fcntl.arg.fl.l_start,
 905                                          end_of(p->u.fcntl.arg.fl.l_start,
 906                                                 p->u.fcntl.arg.fl.l_len),
 907                                          p->u.fcntl.arg.fl.l_type);
 908                 }
 909         }
 910         errno = p->error;
 911         return p->u.fcntl.ret;
 912 }
 913
 914 void failtest_init(int argc, char *argv[])
 915 {
 916         unsigned int i;
 917
 918         for (i = 1; i < argc; i++) {
 919                 if (!strncmp(argv[i], "--failpath=", strlen("--failpath="))) {
 920                         failpath = argv[i] + strlen("--failpath=");
 921                 } else if (strcmp(argv[i], "--tracepath") == 0) {
 922                         tracefd = dup(STDERR_FILENO);
 923                         failtest_timeout_ms = -1;
 924                 }
 925         }
 926         gettimeofday(&start, NULL);
 927 }
 928
 929 /* Free up memory, so valgrind doesn't report leaks. */
 930 static void free_everything(void)
 931 {
 932         unsigned int i;
 933
 934         /* We don't do this in cleanup: needed even for failed opens. */
 935         for (i = 0; i < history_num; i++) {
 936                 if (history[i].type == FAILTEST_OPEN)
 937                         free((char *)history[i].u.open.pathname);
 938         }
 939         free(history);
 940 }
 941
 942 void failtest_exit(int status)
 943 {
 944         int i;
 945
 946         if (control_fd == -1) {
 947                 free_everything();
 948                 exit(status);
 949         }
 950
 951         if (failtest_exit_check) {
 952                 if (!failtest_exit_check(history, history_num))
 953                         child_fail(NULL, 0, "failtest_exit_check failed\n");
 954         }
 955
 956         /* Cleanup everything, in reverse order. */
 957         for (i = history_num - 1; i >= 0; i--)
 958                 if (history[i].cleanup)
 959                         history[i].cleanup(&history[i].u);
 960
 961         free_everything();
 962         tell_parent(SUCCESS);
 963         exit(0);
 964 }