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

   1 #include "config.h"
   2 #include <stdarg.h>
   3 #include <string.h>
   4 #include <stdio.h>
   5 #include <stdarg.h>
   6 #include <ctype.h>
   7 #include <err.h>
   8 #include <unistd.h>
   9 #include <poll.h>
  10 #include <errno.h>
  11 #include <sys/types.h>
  12 #include <sys/wait.h>
  13 #include <sys/stat.h>
  14 #include <sys/time.h>
  15 #include <assert.h>
  16 #include <ccan/read_write_all/read_write_all.h>
  17 #include <ccan/failtest/failtest_proto.h>
  18 #include <ccan/failtest/failtest.h>
  19 #include <ccan/build_assert/build_assert.h>
  20
  21 enum failtest_result (*failtest_hook)(struct failtest_call *, unsigned);
  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 static unsigned int probe_count = 0;
  52
  53 static struct write_call *child_writes = NULL;
  54 static unsigned int child_writes_num = 0;
  55
  56 static pid_t lock_owner;
  57 static struct lock_info *locks = NULL;
  58 static unsigned int lock_num = 0;
  59
  60 static const char info_to_arg[] = "mceoxprwf";
  61
  62 /* Dummy call used for failtest_undo wrappers. */
  63 static struct failtest_call unrecorded_call;
  64
  65 static struct failtest_call *add_history_(enum failtest_call_type type,
  66                                           const char *file,
  67                                           unsigned int line,
  68                                           const void *elem,
  69                                           size_t elem_size)
  70 {
  71         /* NULL file is how we suppress failure. */
  72         if (!file)
  73                 return &unrecorded_call;
  74
  75         history = realloc(history, (history_num + 1) * sizeof(*history));
  76         history[history_num].type = type;
  77         history[history_num].file = file;
  78         history[history_num].line = line;
  79         history[history_num].cleanup = NULL;
  80         memcpy(&history[history_num].u, elem, elem_size);
  81         return &history[history_num++];
  82 }
  83
  84 #define add_history(type, file, line, elem) \
  85         add_history_((type), (file), (line), (elem), sizeof(*(elem)))
  86
  87 /* We do a fake call inside a sizeof(), to check types. */
  88 #define set_cleanup(call, clean, type)                  \
  89         (call)->cleanup = (void *)((void)sizeof(clean((type *)NULL),1), (clean))
  90
  91 static bool read_write_info(int fd)
  92 {
  93         struct write_call *w;
  94         char *buf;
  95
  96         /* We don't need all of this, but it's simple. */
  97         child_writes = realloc(child_writes,
  98                                (child_writes_num+1) * sizeof(child_writes[0]));
  99         w = &child_writes[child_writes_num];
 100         if (!read_all(fd, w, sizeof(*w)))
 101                 return false;
 102
 103         w->buf = buf = malloc(w->count);
 104         if (!read_all(fd, buf, w->count))
 105                 return false;
 106
 107         child_writes_num++;
 108         return true;
 109 }
 110
 111 static char *failpath_string(void)
 112 {
 113         unsigned int i;
 114         char *ret = malloc(history_num + 1);
 115
 116         for (i = 0; i < history_num; i++) {
 117                 ret[i] = info_to_arg[history[i].type];
 118                 if (history[i].fail)
 119                         ret[i] = toupper(ret[i]);
 120         }
 121         ret[i] = '\0';
 122         return ret;
 123 }
 124
 125 static void tell_parent(enum info_type type)
 126 {
 127         if (control_fd != -1)
 128                 write_all(control_fd, &type, sizeof(type));
 129 }
 130
 131 static void child_fail(const char *out, size_t outlen, const char *fmt, ...)
 132 {
 133         va_list ap;
 134         char *path = failpath_string();
 135
 136         va_start(ap, fmt);
 137         vfprintf(stderr, fmt, ap);
 138         va_end(ap);
 139
 140         fprintf(stderr, "%.*s", (int)outlen, out);
 141         printf("To reproduce: --failpath=%s\n", path);
 142         free(path);
 143         tell_parent(FAILURE);
 144         exit(1);
 145 }
 146
 147 static void trace(const char *fmt, ...)
 148 {
 149         va_list ap;
 150
 151         if (tracefd == -1)
 152                 return;
 153
 154         va_start(ap, fmt);
 155         vdprintf(tracefd, fmt, ap);
 156         va_end(ap);
 157 }
 158
 159 static pid_t child;
 160
 161 static void hand_down(int signum)
 162 {
 163         kill(child, signum);
 164 }
 165
 166 static void release_locks(void)
 167 {
 168         /* Locks were never acquired/reacquired? */
 169         if (lock_owner == 0)
 170                 return;
 171
 172         /* We own them?  Release them all. */
 173         if (lock_owner == getpid()) {
 174                 unsigned int i;
 175                 struct flock fl;
 176                 fl.l_type = F_UNLCK;
 177                 fl.l_whence = SEEK_SET;
 178                 fl.l_start = 0;
 179                 fl.l_len = 0;
 180
 181                 for (i = 0; i < lock_num; i++)
 182                         fcntl(locks[i].fd, F_SETLK, &fl);
 183         } else {
 184                 /* Our parent must have them; pass request up. */
 185                 enum info_type type = RELEASE_LOCKS;
 186                 assert(control_fd != -1);
 187                 write_all(control_fd, &type, sizeof(type));
 188         }
 189         lock_owner = 0;
 190 }
 191
 192 /* off_t is a signed type.  Getting its max is non-trivial. */
 193 static off_t off_max(void)
 194 {
 195         BUILD_ASSERT(sizeof(off_t) == 4 || sizeof(off_t) == 8);
 196         if (sizeof(off_t) == 4)
 197                 return (off_t)0x7FFFFFF;
 198         else
 199                 return (off_t)0x7FFFFFFFFFFFFFFULL;
 200 }
 201
 202 static void get_locks(void)
 203 {
 204         unsigned int i;
 205         struct flock fl;
 206
 207         if (lock_owner == getpid())
 208                 return;
 209
 210         if (lock_owner != 0) {
 211                 enum info_type type = RELEASE_LOCKS;
 212                 assert(control_fd != -1);
 213                 write_all(control_fd, &type, sizeof(type));
 214         }
 215
 216         fl.l_whence = SEEK_SET;
 217
 218         for (i = 0; i < lock_num; i++) {
 219                 fl.l_type = locks[i].type;
 220                 fl.l_start = locks[i].start;
 221                 if (locks[i].end == off_max())
 222                         fl.l_len = 0;
 223                 else
 224                         fl.l_len = locks[i].end - locks[i].start + 1;
 225
 226                 if (fcntl(locks[i].fd, F_SETLKW, &fl) != 0)
 227                         abort();
 228         }
 229         lock_owner = getpid();
 230 }
 231
 232 struct saved_file {
 233         struct saved_file *next;
 234         int fd;
 235         void *contents;
 236         off_t off, len;
 237 };
 238
 239 static struct saved_file *save_file(struct saved_file *next, int fd)
 240 {
 241         struct saved_file *s = malloc(sizeof(*s));
 242
 243         s->next = next;
 244         s->fd = fd;
 245         s->off = lseek(fd, 0, SEEK_CUR);
 246         /* Special file?  Erk... */
 247         assert(s->off != -1);
 248         s->len = lseek(fd, 0, SEEK_END);
 249         lseek(fd, 0, SEEK_SET);
 250         s->contents = malloc(s->len);
 251         if (read(fd, s->contents, s->len) != s->len)
 252                 err(1, "Failed to save %zu bytes", (size_t)s->len);
 253         lseek(fd, s->off, SEEK_SET);
 254         return s;
 255 }
 256
 257 /* We have little choice but to save and restore open files: mmap means we
 258  * can really intercept changes in the child.
 259  *
 260  * We could do non-mmap'ed files on demand, however. */
 261 static struct saved_file *save_files(void)
 262 {
 263         struct saved_file *files = NULL;
 264         int i;
 265
 266         /* Figure out the set of live fds. */
 267         for (i = history_num - 2; i >= 0; i--) {
 268                 if (history[i].type == FAILTEST_OPEN) {
 269                         int fd = history[i].u.open.ret;
 270                         /* Only do successful, writable fds. */
 271                         if (fd < 0)
 272                                 continue;
 273
 274                         /* If it was closed, cleanup == NULL. */
 275                         if (!history[i].cleanup)
 276                                 continue;
 277
 278                         if ((history[i].u.open.flags & O_RDWR) == O_RDWR) {
 279                                 files = save_file(files, fd);
 280                         } else if ((history[i].u.open.flags & O_WRONLY)
 281                                    == O_WRONLY) {
 282                                 /* FIXME: Handle O_WRONLY.  Open with O_RDWR? */
 283                                 abort();
 284                         }
 285                 }
 286         }
 287
 288         return files;
 289 }
 290
 291 static void restore_files(struct saved_file *s)
 292 {
 293         while (s) {
 294                 struct saved_file *next = s->next;
 295
 296                 lseek(s->fd, 0, SEEK_SET);
 297                 if (write(s->fd, s->contents, s->len) != s->len)
 298                         err(1, "Failed to restore %zu bytes", (size_t)s->len);
 299                 if (ftruncate(s->fd, s->len) != 0)
 300                         err(1, "Failed to trim file to length %zu",
 301                             (size_t)s->len);
 302                 free(s->contents);
 303                 lseek(s->fd, s->off, SEEK_SET);
 304                 free(s);
 305                 s = next;
 306         }
 307 }
 308
 309 /* Free up memory, so valgrind doesn't report leaks. */
 310 static void free_everything(void)
 311 {
 312         unsigned int i;
 313
 314         /* We don't do this in cleanup: needed even for failed opens. */
 315         for (i = 0; i < history_num; i++) {
 316                 if (history[i].type == FAILTEST_OPEN)
 317                         free((char *)history[i].u.open.pathname);
 318         }
 319         free(history);
 320 }
 321
 322 static NORETURN void failtest_cleanup(bool forced_cleanup, int status)
 323 {
 324         int i;
 325
 326         /* For children, we don't care if they "failed" the testing. */
 327         if (control_fd != -1)
 328                 status = 0;
 329
 330         if (forced_cleanup)
 331                 history_num--;
 332
 333         /* Cleanup everything, in reverse order. */
 334         for (i = history_num - 1; i >= 0; i--) {
 335                 if (!history[i].cleanup)
 336                         continue;
 337                 if (!forced_cleanup) {
 338                         printf("Leak at %s:%u: --failpath=%s\n",
 339                                history[i].file, history[i].line,
 340                                failpath_string());
 341                         status = 1;
 342                 }
 343                 history[i].cleanup(&history[i].u);
 344         }
 345
 346         free_everything();
 347         tell_parent(SUCCESS);
 348         exit(status);
 349 }
 350
 351 static bool should_fail(struct failtest_call *call)
 352 {
 353         int status;
 354         int control[2], output[2];
 355         enum info_type type = UNEXPECTED;
 356         char *out = NULL;
 357         size_t outlen = 0;
 358         struct saved_file *files;
 359
 360         /* Are we probing? */
 361         if (probe_count && --probe_count == 0)
 362                 failtest_cleanup(true, 0);
 363
 364         if (call == &unrecorded_call)
 365                 return false;
 366
 367         if (failpath) {
 368                 /* + means continue after end, like normal. */
 369                 if (*failpath == '+')
 370                         failpath = NULL;
 371                 else if (*failpath == '\0') {
 372                         /* Continue, but don't inject errors. */
 373                         return call->fail = false;
 374                 } else {
 375                         if (tolower((unsigned char)*failpath)
 376                             != info_to_arg[call->type])
 377                                 errx(1, "Failpath expected '%c' got '%c'\n",
 378                                      info_to_arg[call->type], *failpath);
 379                         call->fail = isupper((unsigned char)*(failpath++));
 380                         return call->fail;
 381                 }
 382         }
 383
 384         /* Attach debugger if they asked for it. */
 385         if (debugpath && history_num == strlen(debugpath)) {
 386                 unsigned int i;
 387
 388                 for (i = 0; i < history_num; i++) {
 389                         unsigned char c = info_to_arg[history[i].type];
 390                         if (history[i].fail)
 391                                 c = toupper(c);
 392                         if (c != debugpath[i])
 393                                 break;
 394                 }
 395                 if (i == history_num) {
 396                         char str[80];
 397
 398                         /* Don't timeout. */
 399                         signal(SIGUSR1, SIG_IGN);
 400                         sprintf(str, "xterm -e gdb /proc/%d/exe %d &",
 401                                 getpid(), getpid());
 402                         if (system(str) == 0)
 403                                 sleep(5);
 404                 }
 405         }
 406
 407         if (failtest_hook) {
 408                 switch (failtest_hook(history, history_num)) {
 409                 case FAIL_OK:
 410                         break;
 411                 case FAIL_DONT_FAIL:
 412                         call->fail = false;
 413                         return false;
 414                 case FAIL_PROBE:
 415                         /* Already down probe path?  Stop now. */
 416                         if (probe_count)
 417                                 failtest_cleanup(true, 0);
 418                         /* FIXME: We should run *parent* and run probe until
 419                          * calls match up again. */
 420                         probe_count = 3;
 421                         break;
 422                 default:
 423                         abort();
 424                 }
 425         }
 426
 427         files = save_files();
 428
 429         /* We're going to fail in the child. */
 430         call->fail = true;
 431         if (pipe(control) != 0 || pipe(output) != 0)
 432                 err(1, "opening pipe");
 433
 434         /* Prevent double-printing (in child and parent) */
 435         fflush(stdout);
 436         child = fork();
 437         if (child == -1)
 438                 err(1, "forking failed");
 439
 440         if (child == 0) {
 441                 if (tracefd != -1) {
 442                         struct timeval now;
 443                         const char *p;
 444                         gettimeofday(&now, NULL);
 445                         if (now.tv_usec < start.tv_usec) {
 446                                 now.tv_sec--;
 447                                 now.tv_usec += 1000000;
 448                         }
 449                         now.tv_usec -= start.tv_usec;
 450                         now.tv_sec -= start.tv_sec;
 451                         p = failpath_string();
 452                         trace("%u->%u (%u.%02u): %s (", getppid(), getpid(),
 453                               (int)now.tv_sec, (int)now.tv_usec / 10000, p);
 454                         free((char *)p);
 455                         p = strrchr(history[history_num-1].file, '/');
 456                         if (p)
 457                                 trace("%s", p+1);
 458                         else
 459                                 trace("%s", history[history_num-1].file);
 460                         trace(":%u)\n", history[history_num-1].line);
 461                 }
 462                 close(control[0]);
 463                 close(output[0]);
 464                 dup2(output[1], STDOUT_FILENO);
 465                 dup2(output[1], STDERR_FILENO);
 466                 if (output[1] != STDOUT_FILENO && output[1] != STDERR_FILENO)
 467                         close(output[1]);
 468                 control_fd = control[1];
 469                 return true;
 470         }
 471
 472         signal(SIGUSR1, hand_down);
 473
 474         close(control[1]);
 475         close(output[1]);
 476
 477         /* We grab output so we can display it; we grab writes so we
 478          * can compare. */
 479         do {
 480                 struct pollfd pfd[2];
 481                 int ret;
 482
 483                 pfd[0].fd = output[0];
 484                 pfd[0].events = POLLIN|POLLHUP;
 485                 pfd[1].fd = control[0];
 486                 pfd[1].events = POLLIN|POLLHUP;
 487
 488                 if (type == SUCCESS)
 489                         ret = poll(pfd, 1, failtest_timeout_ms);
 490                 else
 491                         ret = poll(pfd, 2, failtest_timeout_ms);
 492
 493                 if (ret == 0)
 494                         hand_down(SIGUSR1);
 495                 if (ret < 0) {
 496                         if (errno == EINTR)
 497                                 continue;
 498                         err(1, "Poll returned %i", ret);
 499                 }
 500
 501                 if (pfd[0].revents & POLLIN) {
 502                         ssize_t len;
 503
 504                         out = realloc(out, outlen + 8192);
 505                         len = read(output[0], out + outlen, 8192);
 506                         outlen += len;
 507                 } else if (type != SUCCESS && (pfd[1].revents & POLLIN)) {
 508                         if (read_all(control[0], &type, sizeof(type))) {
 509                                 if (type == WRITE) {
 510                                         if (!read_write_info(control[0]))
 511                                                 break;
 512                                 } else if (type == RELEASE_LOCKS) {
 513                                         release_locks();
 514                                         /* FIXME: Tell them we're done... */
 515                                 }
 516                         }
 517                 } else if (pfd[0].revents & POLLHUP) {
 518                         break;
 519                 }
 520         } while (type != FAILURE);
 521
 522         close(output[0]);
 523         close(control[0]);
 524         waitpid(child, &status, 0);
 525         if (!WIFEXITED(status)) {
 526                 if (WTERMSIG(status) == SIGUSR1)
 527                         child_fail(out, outlen, "Timed out");
 528                 else
 529                         child_fail(out, outlen, "Killed by signal %u: ",
 530                                    WTERMSIG(status));
 531         }
 532         /* Child printed failure already, just pass up exit code. */
 533         if (type == FAILURE) {
 534                 fprintf(stderr, "%.*s", (int)outlen, out);
 535                 tell_parent(type);
 536                 exit(WEXITSTATUS(status) ? WEXITSTATUS(status) : 1);
 537         }
 538         if (WEXITSTATUS(status) != 0)
 539                 child_fail(out, outlen, "Exited with status %i: ",
 540                            WEXITSTATUS(status));
 541
 542         free(out);
 543         signal(SIGUSR1, SIG_DFL);
 544
 545         restore_files(files);
 546
 547         /* We continue onwards without failing. */
 548         call->fail = false;
 549         return false;
 550 }
 551
 552 static void cleanup_calloc(struct calloc_call *call)
 553 {
 554         free(call->ret);
 555 }
 556
 557 void *failtest_calloc(size_t nmemb, size_t size,
 558                       const char *file, unsigned line)
 559 {
 560         struct failtest_call *p;
 561         struct calloc_call call;
 562         call.nmemb = nmemb;
 563         call.size = size;
 564         p = add_history(FAILTEST_CALLOC, file, line, &call);
 565
 566         if (should_fail(p)) {
 567                 p->u.calloc.ret = NULL;
 568                 p->error = ENOMEM;
 569         } else {
 570                 p->u.calloc.ret = calloc(nmemb, size);
 571                 set_cleanup(p, cleanup_calloc, struct calloc_call);
 572         }
 573         errno = p->error;
 574         return p->u.calloc.ret;
 575 }
 576
 577 static void cleanup_malloc(struct malloc_call *call)
 578 {
 579         free(call->ret);
 580 }
 581
 582 void *failtest_malloc(size_t size, const char *file, unsigned line)
 583 {
 584         struct failtest_call *p;
 585         struct malloc_call call;
 586         call.size = size;
 587
 588         p = add_history(FAILTEST_MALLOC, file, line, &call);
 589         if (should_fail(p)) {
 590                 p->u.calloc.ret = NULL;
 591                 p->error = ENOMEM;
 592         } else {
 593                 p->u.calloc.ret = malloc(size);
 594                 set_cleanup(p, cleanup_malloc, struct malloc_call);
 595         }
 596         errno = p->error;
 597         return p->u.calloc.ret;
 598 }
 599
 600 static void cleanup_realloc(struct realloc_call *call)
 601 {
 602         free(call->ret);
 603 }
 604
 605 /* Walk back and find out if we got this ptr from a previous routine. */
 606 static void fixup_ptr_history(void *ptr, unsigned int last)
 607 {
 608         int i;
 609
 610         /* Start at end of history, work back. */
 611         for (i = last - 1; i >= 0; i--) {
 612                 switch (history[i].type) {
 613                 case FAILTEST_REALLOC:
 614                         if (history[i].u.realloc.ret == ptr) {
 615                                 history[i].cleanup = NULL;
 616                                 return;
 617                         }
 618                         break;
 619                 case FAILTEST_MALLOC:
 620                         if (history[i].u.malloc.ret == ptr) {
 621                                 history[i].cleanup = NULL;
 622                                 return;
 623                         }
 624                         break;
 625                 case FAILTEST_CALLOC:
 626                         if (history[i].u.calloc.ret == ptr) {
 627                                 history[i].cleanup = NULL;
 628                                 return;
 629                         }
 630                         break;
 631                 default:
 632                         break;
 633                 }
 634         }
 635 }
 636
 637 void *failtest_realloc(void *ptr, size_t size, const char *file, unsigned line)
 638 {
 639         struct failtest_call *p;
 640         struct realloc_call call;
 641         call.size = size;
 642         p = add_history(FAILTEST_REALLOC, file, line, &call);
 643
 644         /* FIXME: Try one child moving allocation, one not. */
 645         if (should_fail(p)) {
 646                 p->u.realloc.ret = NULL;
 647                 p->error = ENOMEM;
 648         } else {
 649                 fixup_ptr_history(ptr, history_num-1);
 650                 p->u.realloc.ret = realloc(ptr, size);
 651                 set_cleanup(p, cleanup_realloc, struct realloc_call);
 652         }
 653         errno = p->error;
 654         return p->u.realloc.ret;
 655 }
 656
 657 void failtest_free(void *ptr)
 658 {
 659         fixup_ptr_history(ptr, history_num);
 660         free(ptr);
 661 }
 662
 663 static void cleanup_open(struct open_call *call)
 664 {
 665         close(call->ret);
 666 }
 667
 668 int failtest_open(const char *pathname,
 669                   const char *file, unsigned line, ...)
 670 {
 671         struct failtest_call *p;
 672         struct open_call call;
 673         va_list ap;
 674
 675         call.pathname = strdup(pathname);
 676         va_start(ap, line);
 677         call.flags = va_arg(ap, int);
 678         if (call.flags & O_CREAT) {
 679                 call.mode = va_arg(ap, mode_t);
 680                 va_end(ap);
 681         }
 682         p = add_history(FAILTEST_OPEN, file, line, &call);
 683         /* Avoid memory leak! */
 684         if (p == &unrecorded_call)
 685                 free((char *)call.pathname);
 686         p->u.open.ret = open(pathname, call.flags, call.mode);
 687
 688         if (!failpath && p->u.open.ret == -1) {
 689                 p->fail = false;
 690                 p->error = errno;
 691         } else if (should_fail(p)) {
 692                 close(p->u.open.ret);
 693                 p->u.open.ret = -1;
 694                 /* FIXME: Play with error codes? */
 695                 p->error = EACCES;
 696         } else {
 697                 set_cleanup(p, cleanup_open, struct open_call);
 698         }
 699         errno = p->error;
 700         return p->u.open.ret;
 701 }
 702
 703 static void cleanup_pipe(struct pipe_call *call)
 704 {
 705         if (!call->closed[0])
 706                 close(call->fds[0]);
 707         if (!call->closed[1])
 708                 close(call->fds[1]);
 709 }
 710
 711 int failtest_pipe(int pipefd[2], const char *file, unsigned line)
 712 {
 713         struct failtest_call *p;
 714         struct pipe_call call;
 715
 716         p = add_history(FAILTEST_PIPE, file, line, &call);
 717         if (should_fail(p)) {
 718                 p->u.open.ret = -1;
 719                 /* FIXME: Play with error codes? */
 720                 p->error = EMFILE;
 721         } else {
 722                 p->u.pipe.ret = pipe(p->u.pipe.fds);
 723                 p->u.pipe.closed[0] = p->u.pipe.closed[1] = false;
 724                 set_cleanup(p, cleanup_pipe, struct pipe_call);
 725         }
 726         /* This causes valgrind to notice if they use pipefd[] after failure */
 727         memcpy(pipefd, p->u.pipe.fds, sizeof(p->u.pipe.fds));
 728         errno = p->error;
 729         return p->u.pipe.ret;
 730 }
 731
 732 ssize_t failtest_pread(int fd, void *buf, size_t count, off_t off,
 733                        const char *file, unsigned line)
 734 {
 735         struct failtest_call *p;
 736         struct read_call call;
 737         call.fd = fd;
 738         call.buf = buf;
 739         call.count = count;
 740         call.off = off;
 741         p = add_history(FAILTEST_READ, file, line, &call);
 742
 743         /* FIXME: Try partial read returns. */
 744         if (should_fail(p)) {
 745                 p->u.read.ret = -1;
 746                 p->error = EIO;
 747         } else {
 748                 p->u.read.ret = pread(fd, buf, count, off);
 749         }
 750         errno = p->error;
 751         return p->u.read.ret;
 752 }
 753
 754 ssize_t failtest_pwrite(int fd, const void *buf, size_t count, off_t off,
 755                         const char *file, unsigned line)
 756 {
 757         struct failtest_call *p;
 758         struct write_call call;
 759
 760         call.fd = fd;
 761         call.buf = buf;
 762         call.count = count;
 763         call.off = off;
 764         p = add_history(FAILTEST_WRITE, file, line, &call);
 765
 766         /* If we're a child, we need to make sure we write the same thing
 767          * to non-files as the parent does, so tell it. */
 768         if (control_fd != -1 && off == (off_t)-1) {
 769                 enum info_type type = WRITE;
 770
 771                 write_all(control_fd, &type, sizeof(type));
 772                 write_all(control_fd, &p->u.write, sizeof(p->u.write));
 773                 write_all(control_fd, buf, count);
 774         }
 775
 776         /* FIXME: Try partial write returns. */
 777         if (should_fail(p)) {
 778                 p->u.write.ret = -1;
 779                 p->error = EIO;
 780         } else {
 781                 /* FIXME: We assume same write order in parent and child */
 782                 if (off == (off_t)-1 && child_writes_num != 0) {
 783                         if (child_writes[0].fd != fd)
 784                                 errx(1, "Child wrote to fd %u, not %u?",
 785                                      child_writes[0].fd, fd);
 786                         if (child_writes[0].off != p->u.write.off)
 787                                 errx(1, "Child wrote to offset %zu, not %zu?",
 788                                      (size_t)child_writes[0].off,
 789                                      (size_t)p->u.write.off);
 790                         if (child_writes[0].count != count)
 791                                 errx(1, "Child wrote length %zu, not %zu?",
 792                                      child_writes[0].count, count);
 793                         if (memcmp(child_writes[0].buf, buf, count)) {
 794                                 child_fail(NULL, 0,
 795                                            "Child wrote differently to"
 796                                            " fd %u than we did!\n", fd);
 797                         }
 798                         free((char *)child_writes[0].buf);
 799                         child_writes_num--;
 800                         memmove(&child_writes[0], &child_writes[1],
 801                                 sizeof(child_writes[0]) * child_writes_num);
 802
 803                         /* Is this is a socket or pipe, child wrote it
 804                            already. */
 805                         if (p->u.write.off == (off_t)-1) {
 806                                 p->u.write.ret = count;
 807                                 errno = p->error;
 808                                 return p->u.write.ret;
 809                         }
 810                 }
 811                 p->u.write.ret = pwrite(fd, buf, count, off);
 812         }
 813         errno = p->error;
 814         return p->u.write.ret;
 815 }
 816
 817 ssize_t failtest_read(int fd, void *buf, size_t count,
 818                       const char *file, unsigned line)
 819 {
 820         return failtest_pread(fd, buf, count, lseek(fd, 0, SEEK_CUR),
 821                               file, line);
 822 }
 823
 824 ssize_t failtest_write(int fd, const void *buf, size_t count,
 825                        const char *file, unsigned line)
 826 {
 827         return failtest_pwrite(fd, buf, count, lseek(fd, 0, SEEK_CUR),
 828                                file, line);
 829 }
 830
 831 static struct lock_info *WARN_UNUSED_RESULT
 832 add_lock(struct lock_info *locks, int fd, off_t start, off_t end, int type)
 833 {
 834         unsigned int i;
 835         struct lock_info *l;
 836
 837         for (i = 0; i < lock_num; i++) {
 838                 l = &locks[i];
 839
 840                 if (l->fd != fd)
 841                         continue;
 842                 /* Four cases we care about:
 843                  * Start overlap:
 844                  *      l =    |      |
 845                  *      new = |   |
 846                  * Mid overlap:
 847                  *      l =    |      |
 848                  *      new =    |  |
 849                  * End overlap:
 850                  *      l =    |      |
 851                  *      new =      |    |
 852                  * Total overlap:
 853                  *      l =    |      |
 854                  *      new = |         |
 855                  */
 856                 if (start > l->start && end < l->end) {
 857                         /* Mid overlap: trim entry, add new one. */
 858                         off_t new_start, new_end;
 859                         new_start = end + 1;
 860                         new_end = l->end;
 861                         l->end = start - 1;
 862                         locks = add_lock(locks,
 863                                          fd, new_start, new_end, l->type);
 864                         l = &locks[i];
 865                 } else if (start <= l->start && end >= l->end) {
 866                         /* Total overlap: eliminate entry. */
 867                         l->end = 0;
 868                         l->start = 1;
 869                 } else if (end >= l->start && end < l->end) {
 870                         /* Start overlap: trim entry. */
 871                         l->start = end + 1;
 872                 } else if (start > l->start && start <= l->end) {
 873                         /* End overlap: trim entry. */
 874                         l->end = start-1;
 875                 }
 876                 /* Nothing left?  Remove it. */
 877                 if (l->end < l->start) {
 878                         memmove(l, l + 1, (--lock_num - i) * sizeof(l[0]));
 879                         i--;
 880                 }
 881         }
 882
 883         if (type != F_UNLCK) {
 884                 locks = realloc(locks, (lock_num + 1) * sizeof(*locks));
 885                 l = &locks[lock_num++];
 886                 l->fd = fd;
 887                 l->start = start;
 888                 l->end = end;
 889                 l->type = type;
 890         }
 891         return locks;
 892 }
 893
 894 /* We trap this so we can record it: we don't fail it. */
 895 int failtest_close(int fd, const char *file, unsigned line)
 896 {
 897         int i;
 898         struct close_call call;
 899         struct failtest_call *p;
 900
 901         call.fd = fd;
 902         p = add_history(FAILTEST_CLOSE, file, line, &call);
 903         p->fail = false;
 904
 905         /* Consume close from failpath. */
 906         if (failpath)
 907                 if (should_fail(p))
 908                         abort();
 909
 910         if (fd < 0)
 911                 return close(fd);
 912
 913         /* Trace history to find source of fd. */
 914         for (i = history_num-1; i >= 0; i--) {
 915                 switch (history[i].type) {
 916                 case FAILTEST_PIPE:
 917                         /* From a pipe? */
 918                         if (history[i].u.pipe.fds[0] == fd) {
 919                                 assert(!history[i].u.pipe.closed[0]);
 920                                 history[i].u.pipe.closed[0] = true;
 921                                 if (history[i].u.pipe.closed[1])
 922                                         history[i].cleanup = NULL;
 923                                 goto out;
 924                         }
 925                         if (history[i].u.pipe.fds[1] == fd) {
 926                                 assert(!history[i].u.pipe.closed[1]);
 927                                 history[i].u.pipe.closed[1] = true;
 928                                 if (history[i].u.pipe.closed[0])
 929                                         history[i].cleanup = NULL;
 930                                 goto out;
 931                         }
 932                         break;
 933                 case FAILTEST_OPEN:
 934                         if (history[i].u.open.ret == fd) {
 935                                 assert((void *)history[i].cleanup
 936                                        == (void *)cleanup_open);
 937                                 history[i].cleanup = NULL;
 938                                 goto out;
 939                         }
 940                         break;
 941                 default:
 942                         break;
 943                 }
 944         }
 945
 946 out:
 947         locks = add_lock(locks, fd, 0, off_max(), F_UNLCK);
 948         return close(fd);
 949 }
 950
 951 /* Zero length means "to end of file" */
 952 static off_t end_of(off_t start, off_t len)
 953 {
 954         if (len == 0)
 955                 return off_max();
 956         return start + len - 1;
 957 }
 958
 959 /* FIXME: This only handles locks, really. */
 960 int failtest_fcntl(int fd, const char *file, unsigned line, int cmd, ...)
 961 {
 962         struct failtest_call *p;
 963         struct fcntl_call call;
 964         va_list ap;
 965
 966         call.fd = fd;
 967         call.cmd = cmd;
 968
 969         /* Argument extraction. */
 970         switch (cmd) {
 971         case F_SETFL:
 972         case F_SETFD:
 973                 va_start(ap, cmd);
 974                 call.arg.l = va_arg(ap, long);
 975                 va_end(ap);
 976                 return fcntl(fd, cmd, call.arg.l);
 977         case F_GETFD:
 978         case F_GETFL:
 979                 return fcntl(fd, cmd);
 980         case F_GETLK:
 981                 get_locks();
 982                 va_start(ap, cmd);
 983                 call.arg.fl = *va_arg(ap, struct flock *);
 984                 va_end(ap);
 985                 return fcntl(fd, cmd, &call.arg.fl);
 986         case F_SETLK:
 987         case F_SETLKW:
 988                 va_start(ap, cmd);
 989                 call.arg.fl = *va_arg(ap, struct flock *);
 990                 va_end(ap);
 991                 break;
 992         default:
 993                 /* This means you need to implement it here. */
 994                 err(1, "failtest: unknown fcntl %u", cmd);
 995         }
 996
 997         p = add_history(FAILTEST_FCNTL, file, line, &call);
 998
 999         if (should_fail(p)) {
1000                 p->u.fcntl.ret = -1;
1001                 if (p->u.fcntl.cmd == F_SETLK)
1002                         p->error = EAGAIN;
1003                 else
1004                         p->error = EDEADLK;
1005         } else {
1006                 get_locks();
1007                 p->u.fcntl.ret = fcntl(p->u.fcntl.fd, p->u.fcntl.cmd,
1008                                        &p->u.fcntl.arg.fl);
1009                 if (p->u.fcntl.ret == -1)
1010                         p->error = errno;
1011                 else {
1012                         /* We don't handle anything else yet. */
1013                         assert(p->u.fcntl.arg.fl.l_whence == SEEK_SET);
1014                         locks = add_lock(locks,
1015                                          p->u.fcntl.fd,
1016                                          p->u.fcntl.arg.fl.l_start,
1017                                          end_of(p->u.fcntl.arg.fl.l_start,
1018                                                 p->u.fcntl.arg.fl.l_len),
1019                                          p->u.fcntl.arg.fl.l_type);
1020                 }
1021         }
1022         errno = p->error;
1023         return p->u.fcntl.ret;
1024 }
1025
1026 void failtest_init(int argc, char *argv[])
1027 {
1028         unsigned int i;
1029
1030         for (i = 1; i < argc; i++) {
1031                 if (!strncmp(argv[i], "--failpath=", strlen("--failpath="))) {
1032                         failpath = argv[i] + strlen("--failpath=");
1033                 } else if (strcmp(argv[i], "--tracepath") == 0) {
1034                         tracefd = dup(STDERR_FILENO);
1035                         failtest_timeout_ms = -1;
1036                 } else if (!strncmp(argv[i], "--debugpath=",
1037                                     strlen("--debugpath="))) {
1038                         debugpath = argv[i] + strlen("--debugpath=");
1039                 }
1040         }
1041         gettimeofday(&start, NULL);
1042 }
1043
1044 void failtest_exit(int status)
1045 {
1046         if (failtest_exit_check) {
1047                 if (!failtest_exit_check(history, history_num))
1048                         child_fail(NULL, 0, "failtest_exit_check failed\n");
1049         }
1050
1051         failtest_cleanup(false, status);
1052 }