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 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         off_t orig = lseek(fd, 0, SEEK_CUR);
 245
 246         /* Special file?  Erk... */
 247         assert(orig != -1);
 248
 249         s->next = next;
 250         s->fd = fd;
 251         s->len = lseek(fd, 0, SEEK_END);
 252         lseek(fd, 0, SEEK_SET);
 253         s->contents = malloc(s->len);
 254         read(fd, s->contents, s->len);
 255         lseek(fd, orig, SEEK_SET);
 256         return s;
 257 }
 258
 259 /* We have little choice but to save and restore open files: mmap means we
 260  * can really intercept changes in the child.
 261  *
 262  * We could do non-mmap'ed files on demand, however. */
 263 static struct saved_file *save_files(void)
 264 {
 265         struct saved_file *files = NULL;
 266         int i;
 267         fd_set closed;
 268
 269         /* Figure out the set of live fds. */
 270         FD_ZERO(&closed);
 271         for (i = history_num - 2; i >= 0; i--) {
 272                 /* FIXME: Handle dup. */
 273                 if (history[i].type == FAILTEST_CLOSE) {
 274                         assert(!FD_ISSET(history[i].u.close.fd, &closed));
 275                         FD_SET(history[i].u.close.fd, &closed);
 276                 } else if (history[i].type == FAILTEST_OPEN) {
 277                         int fd = history[i].u.open.ret;
 278                         /* Only do successful, writable fds. */
 279                         if (fd < 0)
 280                                 continue;
 281
 282                         /* If it wasn't closed again... */
 283                         if (!FD_ISSET(fd, &closed)) {
 284                                 if ((history[i].u.open.flags & O_RDWR)
 285                                     == O_RDWR) {
 286                                         files = save_file(files, fd);
 287                                 } else if ((history[i].u.open.flags & O_WRONLY)
 288                                            == O_WRONLY) {
 289                                         /* FIXME: Handle O_WRONLY.  Open with
 290                                          * O_RDWR? */
 291                                         abort();
 292                                 }
 293                         } else
 294                                 FD_CLR(history[i].u.open.ret, &closed);
 295                 }
 296         }
 297
 298         return files;
 299 }
 300
 301 static void restore_files(struct saved_file *s)
 302 {
 303         while (s) {
 304                 struct saved_file *next = s->next;
 305                 off_t orig = lseek(s->fd, 0, SEEK_CUR);
 306
 307                 lseek(s->fd, 0, SEEK_SET);
 308                 write(s->fd, s->contents, s->len);
 309                 free(s->contents);
 310                 lseek(s->fd, orig, SEEK_SET);
 311                 free(s);
 312                 s = next;
 313         }
 314 }
 315
 316 static bool should_fail(struct failtest_call *call)
 317 {
 318         int status;
 319         int control[2], output[2];
 320         enum info_type type = UNEXPECTED;
 321         char *out = NULL;
 322         size_t outlen = 0;
 323         struct saved_file *files;
 324
 325         if (call == &unrecorded_call)
 326                 return false;
 327
 328         if (failpath) {
 329                 /* + means continue after end, like normal. */
 330                 if (*failpath == '+')
 331                         failpath = NULL;
 332                 else {
 333                         if (tolower(*failpath) != info_to_arg[call->type])
 334                                 errx(1, "Failpath expected '%c' got '%c'\n",
 335                                      info_to_arg[call->type], *failpath);
 336                         call->fail = isupper(*(failpath++));
 337                         return call->fail;
 338                 }
 339         }
 340
 341         if (!failtest_hook(history, history_num)) {
 342                 call->fail = false;
 343                 return false;
 344         }
 345
 346         files = save_files();
 347
 348         /* We're going to fail in the child. */
 349         call->fail = true;
 350         if (pipe(control) != 0 || pipe(output) != 0)
 351                 err(1, "opening pipe");
 352
 353         /* Prevent double-printing (in child and parent) */
 354         fflush(stdout);
 355         child = fork();
 356         if (child == -1)
 357                 err(1, "forking failed");
 358
 359         if (child == 0) {
 360                 if (tracefd != -1) {
 361                         struct timeval now;
 362                         char str[50], *p;
 363                         gettimeofday(&now, NULL);
 364                         if (now.tv_usec < start.tv_usec) {
 365                                 now.tv_sec--;
 366                                 now.tv_usec += 1000000;
 367                         }
 368                         now.tv_usec -= start.tv_usec;
 369                         now.tv_sec -= start.tv_sec;
 370                         sprintf(str, "%u (%u.%02u): ", getpid(),
 371                                 (int)now.tv_sec, (int)now.tv_usec / 10000);
 372                         trace_str(str);
 373                         p = failpath_string();
 374                         trace_str(p);
 375                         free(p);
 376                         trace_str("(");
 377                         p = strchr(history[history_num-1].file, '/');
 378                         if (p)
 379                                 trace_str(p+1);
 380                         else
 381                                 trace_str(history[history_num-1].file);
 382                         sprintf(str, ":%u)\n", history[history_num-1].line);
 383                         trace_str(str);
 384                 }
 385                 close(control[0]);
 386                 close(output[0]);
 387                 dup2(output[1], STDOUT_FILENO);
 388                 dup2(output[1], STDERR_FILENO);
 389                 if (output[1] != STDOUT_FILENO && output[1] != STDERR_FILENO)
 390                         close(output[1]);
 391                 control_fd = control[1];
 392                 return true;
 393         }
 394
 395         signal(SIGUSR1, hand_down);
 396
 397         close(control[1]);
 398         close(output[1]);
 399
 400         /* We grab output so we can display it; we grab writes so we
 401          * can compare. */
 402         do {
 403                 struct pollfd pfd[2];
 404                 int ret;
 405
 406                 pfd[0].fd = output[0];
 407                 pfd[0].events = POLLIN|POLLHUP;
 408                 pfd[1].fd = control[0];
 409                 pfd[1].events = POLLIN|POLLHUP;
 410
 411                 if (type == SUCCESS)
 412                         ret = poll(pfd, 1, failtest_timeout_ms);
 413                 else
 414                         ret = poll(pfd, 2, failtest_timeout_ms);
 415
 416                 if (ret <= 0)
 417                         hand_down(SIGUSR1);
 418
 419                 if (pfd[0].revents & POLLIN) {
 420                         ssize_t len;
 421
 422                         out = realloc(out, outlen + 8192);
 423                         len = read(output[0], out + outlen, 8192);
 424                         outlen += len;
 425                 } else if (type != SUCCESS && (pfd[1].revents & POLLIN)) {
 426                         if (read_all(control[0], &type, sizeof(type))) {
 427                                 if (type == WRITE) {
 428                                         if (!read_write_info(control[0]))
 429                                                 break;
 430                                 } else if (type == RELEASE_LOCKS) {
 431                                         release_locks();
 432                                         /* FIXME: Tell them we're done... */
 433                                 }
 434                         }
 435                 } else if (pfd[0].revents & POLLHUP) {
 436                         break;
 437                 }
 438         } while (type != FAILURE);
 439
 440         close(output[0]);
 441         close(control[0]);
 442         waitpid(child, &status, 0);
 443         if (!WIFEXITED(status))
 444                 child_fail(out, outlen, "Killed by signal %u: ",
 445                            WTERMSIG(status));
 446         /* Child printed failure already, just pass up exit code. */
 447         if (type == FAILURE) {
 448                 fprintf(stderr, "%.*s", (int)outlen, out);
 449                 tell_parent(type);
 450                 exit(WEXITSTATUS(status) ? WEXITSTATUS(status) : 1);
 451         }
 452         if (WEXITSTATUS(status) != 0)
 453                 child_fail(out, outlen, "Exited with status %i: ",
 454                            WEXITSTATUS(status));
 455
 456         free(out);
 457         signal(SIGUSR1, SIG_DFL);
 458
 459         restore_files(files);
 460
 461         /* We continue onwards without failing. */
 462         call->fail = false;
 463         return false;
 464 }
 465
 466 static void cleanup_calloc(struct calloc_call *call)
 467 {
 468         free(call->ret);
 469 }
 470
 471 void *failtest_calloc(size_t nmemb, size_t size,
 472                       const char *file, unsigned line)
 473 {
 474         struct failtest_call *p;
 475         struct calloc_call call;
 476         call.nmemb = nmemb;
 477         call.size = size;
 478         p = add_history(FAILTEST_CALLOC, file, line, &call);
 479
 480         if (should_fail(p)) {
 481                 p->u.calloc.ret = NULL;
 482                 p->error = ENOMEM;
 483         } else {
 484                 p->u.calloc.ret = calloc(nmemb, size);
 485                 set_cleanup(p, cleanup_calloc, struct calloc_call);
 486         }
 487         errno = p->error;
 488         return p->u.calloc.ret;
 489 }
 490
 491 static void cleanup_malloc(struct malloc_call *call)
 492 {
 493         free(call->ret);
 494 }
 495
 496 void *failtest_malloc(size_t size, const char *file, unsigned line)
 497 {
 498         struct failtest_call *p;
 499         struct malloc_call call;
 500         call.size = size;
 501
 502         p = add_history(FAILTEST_MALLOC, file, line, &call);
 503         if (should_fail(p)) {
 504                 p->u.calloc.ret = NULL;
 505                 p->error = ENOMEM;
 506         } else {
 507                 p->u.calloc.ret = malloc(size);
 508                 set_cleanup(p, cleanup_malloc, struct malloc_call);
 509         }
 510         errno = p->error;
 511         return p->u.calloc.ret;
 512 }
 513
 514 static void cleanup_realloc(struct realloc_call *call)
 515 {
 516         free(call->ret);
 517 }
 518
 519 /* Walk back and find out if we got this ptr from a previous routine. */
 520 static void fixup_ptr_history(void *ptr, unsigned int last)
 521 {
 522         int i;
 523
 524         /* Start at end of history, work back. */
 525         for (i = last - 1; i >= 0; i--) {
 526                 switch (history[i].type) {
 527                 case FAILTEST_REALLOC:
 528                         if (history[i].u.realloc.ret == ptr) {
 529                                 history[i].cleanup = NULL;
 530                                 return;
 531                         }
 532                         break;
 533                 case FAILTEST_MALLOC:
 534                         if (history[i].u.malloc.ret == ptr) {
 535                                 history[i].cleanup = NULL;
 536                                 return;
 537                         }
 538                         break;
 539                 case FAILTEST_CALLOC:
 540                         if (history[i].u.calloc.ret == ptr) {
 541                                 history[i].cleanup = NULL;
 542                                 return;
 543                         }
 544                         break;
 545                 default:
 546                         break;
 547                 }
 548         }
 549 }
 550
 551 void *failtest_realloc(void *ptr, size_t size, const char *file, unsigned line)
 552 {
 553         struct failtest_call *p;
 554         struct realloc_call call;
 555         call.size = size;
 556         p = add_history(FAILTEST_REALLOC, file, line, &call);
 557
 558         /* FIXME: Try one child moving allocation, one not. */
 559         if (should_fail(p)) {
 560                 p->u.realloc.ret = NULL;
 561                 p->error = ENOMEM;
 562         } else {
 563                 fixup_ptr_history(ptr, history_num-1);
 564                 p->u.realloc.ret = realloc(ptr, size);
 565                 set_cleanup(p, cleanup_realloc, struct realloc_call);
 566         }
 567         errno = p->error;
 568         return p->u.realloc.ret;
 569 }
 570
 571 void failtest_free(void *ptr)
 572 {
 573         fixup_ptr_history(ptr, history_num);
 574         free(ptr);
 575 }
 576
 577 static void cleanup_open(struct open_call *call)
 578 {
 579         close(call->ret);
 580 }
 581
 582 int failtest_open(const char *pathname,
 583                   const char *file, unsigned line, ...)
 584 {
 585         struct failtest_call *p;
 586         struct open_call call;
 587         va_list ap;
 588
 589         call.pathname = strdup(pathname);
 590         va_start(ap, line);
 591         call.flags = va_arg(ap, int);
 592         if (call.flags & O_CREAT) {
 593                 call.mode = va_arg(ap, mode_t);
 594                 va_end(ap);
 595         }
 596         p = add_history(FAILTEST_OPEN, file, line, &call);
 597         /* Avoid memory leak! */
 598         if (p == &unrecorded_call)
 599                 free((char *)call.pathname);
 600         if (should_fail(p)) {
 601                 p->u.open.ret = -1;
 602                 /* FIXME: Play with error codes? */
 603                 p->error = EACCES;
 604         } else {
 605                 p->u.open.ret = open(pathname, call.flags, call.mode);
 606                 set_cleanup(p, cleanup_open, struct open_call);
 607                 p->u.open.dup_fd = p->u.open.ret;
 608         }
 609         errno = p->error;
 610         return p->u.open.ret;
 611 }
 612
 613 static void cleanup_pipe(struct pipe_call *call)
 614 {
 615         if (!call->closed[0])
 616                 close(call->fds[0]);
 617         if (!call->closed[1])
 618                 close(call->fds[1]);
 619 }
 620
 621 int failtest_pipe(int pipefd[2], const char *file, unsigned line)
 622 {
 623         struct failtest_call *p;
 624         struct pipe_call call;
 625
 626         p = add_history(FAILTEST_PIPE, file, line, &call);
 627         if (should_fail(p)) {
 628                 p->u.open.ret = -1;
 629                 /* FIXME: Play with error codes? */
 630                 p->error = EMFILE;
 631         } else {
 632                 p->u.pipe.ret = pipe(p->u.pipe.fds);
 633                 p->u.pipe.closed[0] = p->u.pipe.closed[1] = false;
 634                 set_cleanup(p, cleanup_pipe, struct pipe_call);
 635         }
 636         /* This causes valgrind to notice if they use pipefd[] after failure */
 637         memcpy(pipefd, p->u.pipe.fds, sizeof(p->u.pipe.fds));
 638         errno = p->error;
 639         return p->u.pipe.ret;
 640 }
 641
 642 static void cleanup_read(struct read_call *call)
 643 {
 644         lseek(call->fd, call->off, SEEK_SET);
 645 }
 646
 647 ssize_t failtest_pread(int fd, void *buf, size_t count, off_t off,
 648                        const char *file, unsigned line)
 649 {
 650         struct failtest_call *p;
 651         struct read_call call;
 652         call.fd = fd;
 653         call.buf = buf;
 654         call.count = count;
 655         call.off = off;
 656         p = add_history(FAILTEST_READ, file, line, &call);
 657
 658         /* FIXME: Try partial read returns. */
 659         if (should_fail(p)) {
 660                 p->u.read.ret = -1;
 661                 p->error = EIO;
 662         } else {
 663                 p->u.read.ret = pread(fd, buf, count, off);
 664                 set_cleanup(p, cleanup_read, struct read_call);
 665         }
 666         errno = p->error;
 667         return p->u.read.ret;
 668 }
 669
 670 static void cleanup_write(struct write_call *call)
 671 {
 672         lseek(call->dup_fd, call->off, SEEK_SET);
 673         write(call->dup_fd, call->saved_contents, call->saved_len);
 674         lseek(call->dup_fd, call->off, SEEK_SET);
 675         ftruncate(call->dup_fd, call->old_filelen);
 676         free(call->saved_contents);
 677 }
 678
 679 ssize_t failtest_pwrite(int fd, const void *buf, size_t count, off_t off,
 680                         const char *file, unsigned line)
 681 {
 682         struct failtest_call *p;
 683         struct write_call call;
 684
 685         call.fd = call.dup_fd = fd;
 686         call.buf = buf;
 687         call.count = count;
 688         call.off = off;
 689         p = add_history(FAILTEST_WRITE, file, line, &call);
 690
 691         /* Save old contents if we can */
 692         if (p->u.write.off != -1) {
 693                 ssize_t ret;
 694                 p->u.write.old_filelen = lseek(fd, 0, SEEK_END);
 695
 696                 /* Write past end of file?  Nothing to save.*/
 697                 if (p->u.write.old_filelen <= p->u.write.off)
 698                         p->u.write.saved_len = 0;
 699                 /* Write which goes over end of file?  Partial save. */
 700                 else if (p->u.write.off + count > p->u.write.old_filelen)
 701                         p->u.write.saved_len = p->u.write.old_filelen
 702                                 - p->u.write.off;
 703                 /* Full save. */
 704                 else
 705                         p->u.write.saved_len = count;
 706
 707                 p->u.write.saved_contents = malloc(p->u.write.saved_len);
 708                 lseek(fd, p->u.write.off, SEEK_SET);
 709                 ret = read(fd, p->u.write.saved_contents, p->u.write.saved_len);
 710                 if (ret != p->u.write.saved_len)
 711                         err(1, "Expected %i bytes, got %i",
 712                             (int)p->u.write.saved_len, (int)ret);
 713                 lseek(fd, p->u.write.off, SEEK_SET);
 714                 set_cleanup(p, cleanup_write, struct write_call);
 715         }
 716
 717         /* If we're a child, tell parent about write. */
 718         if (control_fd != -1) {
 719                 enum info_type type = WRITE;
 720
 721                 write_all(control_fd, &type, sizeof(type));
 722                 write_all(control_fd, &p->u.write, sizeof(p->u.write));
 723                 write_all(control_fd, buf, count);
 724         }
 725
 726         /* FIXME: Try partial write returns. */
 727         if (should_fail(p)) {
 728                 p->u.write.ret = -1;
 729                 p->error = EIO;
 730         } else {
 731                 /* FIXME: We assume same write order in parent and child */
 732                 if (child_writes_num != 0) {
 733                         if (child_writes[0].fd != fd)
 734                                 errx(1, "Child wrote to fd %u, not %u?",
 735                                      child_writes[0].fd, fd);
 736                         if (child_writes[0].off != p->u.write.off)
 737                                 errx(1, "Child wrote to offset %zu, not %zu?",
 738                                      (size_t)child_writes[0].off,
 739                                      (size_t)p->u.write.off);
 740                         if (child_writes[0].count != count)
 741                                 errx(1, "Child wrote length %zu, not %zu?",
 742                                      child_writes[0].count, count);
 743                         if (memcmp(child_writes[0].buf, buf, count)) {
 744                                 child_fail(NULL, 0,
 745                                            "Child wrote differently to"
 746                                            " fd %u than we did!\n", fd);
 747                         }
 748                         free((char *)child_writes[0].buf);
 749                         child_writes_num--;
 750                         memmove(&child_writes[0], &child_writes[1],
 751                                 sizeof(child_writes[0]) * child_writes_num);
 752
 753                         /* Is this is a socket or pipe, child wrote it
 754                            already. */
 755                         if (p->u.write.off == (off_t)-1) {
 756                                 p->u.write.ret = count;
 757                                 errno = p->error;
 758                                 return p->u.write.ret;
 759                         }
 760                 }
 761                 p->u.write.ret = pwrite(fd, buf, count, off);
 762         }
 763         errno = p->error;
 764         return p->u.write.ret;
 765 }
 766
 767 ssize_t failtest_read(int fd, void *buf, size_t count,
 768                       const char *file, unsigned line)
 769 {
 770         return failtest_pread(fd, buf, count, lseek(fd, 0, SEEK_CUR),
 771                               file, line);
 772 }
 773
 774 ssize_t failtest_write(int fd, const void *buf, size_t count,
 775                        const char *file, unsigned line)
 776 {
 777         return failtest_pwrite(fd, buf, count, lseek(fd, 0, SEEK_CUR),
 778                                file, line);
 779 }
 780
 781 static struct lock_info *WARN_UNUSED_RESULT
 782 add_lock(struct lock_info *locks, int fd, off_t start, off_t end, int type)
 783 {
 784         unsigned int i;
 785         struct lock_info *l;
 786
 787         for (i = 0; i < lock_num; i++) {
 788                 l = &locks[i];
 789
 790                 if (l->fd != fd)
 791                         continue;
 792                 /* Four cases we care about:
 793                  * Start overlap:
 794                  *      l =    |      |
 795                  *      new = |   |
 796                  * Mid overlap:
 797                  *      l =    |      |
 798                  *      new =    |  |
 799                  * End overlap:
 800                  *      l =    |      |
 801                  *      new =      |    |
 802                  * Total overlap:
 803                  *      l =    |      |
 804                  *      new = |         |
 805                  */
 806                 if (start > l->start && end < l->end) {
 807                         /* Mid overlap: trim entry, add new one. */
 808                         off_t new_start, new_end;
 809                         new_start = end + 1;
 810                         new_end = l->end;
 811                         l->end = start - 1;
 812                         locks = add_lock(locks,
 813                                          fd, new_start, new_end, l->type);
 814                         l = &locks[i];
 815                 } else if (start <= l->start && end >= l->end) {
 816                         /* Total overlap: eliminate entry. */
 817                         l->end = 0;
 818                         l->start = 1;
 819                 } else if (end >= l->start && end < l->end) {
 820                         /* Start overlap: trim entry. */
 821                         l->start = end + 1;
 822                 } else if (start > l->start && start <= l->end) {
 823                         /* End overlap: trim entry. */
 824                         l->end = start-1;
 825                 }
 826                 /* Nothing left?  Remove it. */
 827                 if (l->end < l->start) {
 828                         memmove(l, l + 1, (--lock_num - i) * sizeof(l[0]));
 829                         i--;
 830                 }
 831         }
 832
 833         if (type != F_UNLCK) {
 834                 locks = realloc(locks, (lock_num + 1) * sizeof(*locks));
 835                 l = &locks[lock_num++];
 836                 l->fd = fd;
 837                 l->start = start;
 838                 l->end = end;
 839                 l->type = type;
 840         }
 841         return locks;
 842 }
 843
 844 /* We only trap this so we can dup fds in case we need to restore. */
 845 int failtest_close(int fd)
 846 {
 847         int new_fd = -1, i;
 848
 849         if (fd < 0)
 850                 return close(fd);
 851
 852         /* Trace history to find source of fd, and if we need to cleanup writes. */
 853         for (i = history_num-1; i >= 0; i--) {
 854                 switch (history[i].type) {
 855                 case FAILTEST_WRITE:
 856                         if (history[i].u.write.fd != fd)
 857                                 break;
 858                         if (!history[i].cleanup)
 859                                 break;
 860                         /* We need to save fd so we can restore file. */
 861                         if (new_fd == -1)
 862                                 new_fd = dup(fd);
 863                         history[i].u.write.dup_fd = new_fd;
 864                         break;
 865                 case FAILTEST_READ:
 866                         /* We don't need to cleanup reads on closed fds. */
 867                         if (history[i].u.read.fd != fd)
 868                                 break;
 869                         history[i].cleanup = NULL;
 870                         break;
 871                 case FAILTEST_PIPE:
 872                         /* From a pipe?  We don't ever restore pipes... */
 873                         if (history[i].u.pipe.fds[0] == fd) {
 874                                 assert(new_fd == -1);
 875                                 history[i].u.pipe.closed[0] = true;
 876                                 goto out;
 877                         }
 878                         if (history[i].u.pipe.fds[1] == fd) {
 879                                 assert(new_fd == -1);
 880                                 history[i].u.pipe.closed[1] = true;
 881                                 goto out;
 882                         }
 883                         break;
 884                 case FAILTEST_OPEN:
 885                         if (history[i].u.open.ret == fd) {
 886                                 history[i].u.open.dup_fd = new_fd;
 887                                 goto out;
 888                         }
 889                         break;
 890                 default:
 891                         break;
 892                 }
 893         }
 894
 895 out:
 896         locks = add_lock(locks, fd, 0, off_max(), F_UNLCK);
 897         return close(fd);
 898 }
 899
 900 /* Zero length means "to end of file" */
 901 static off_t end_of(off_t start, off_t len)
 902 {
 903         if (len == 0)
 904                 return off_max();
 905         return start + len - 1;
 906 }
 907
 908 /* FIXME: This only handles locks, really. */
 909 int failtest_fcntl(int fd, const char *file, unsigned line, int cmd, ...)
 910 {
 911         struct failtest_call *p;
 912         struct fcntl_call call;
 913         va_list ap;
 914
 915         call.fd = fd;
 916         call.cmd = cmd;
 917
 918         /* Argument extraction. */
 919         switch (cmd) {
 920         case F_SETFL:
 921         case F_SETFD:
 922                 va_start(ap, cmd);
 923                 call.arg.l = va_arg(ap, long);
 924                 va_end(ap);
 925                 return fcntl(fd, cmd, call.arg.l);
 926         case F_GETFD:
 927         case F_GETFL:
 928                 return fcntl(fd, cmd);
 929         case F_GETLK:
 930                 get_locks();
 931                 va_start(ap, cmd);
 932                 call.arg.fl = *va_arg(ap, struct flock *);
 933                 va_end(ap);
 934                 return fcntl(fd, cmd, &call.arg.fl);
 935         case F_SETLK:
 936         case F_SETLKW:
 937                 va_start(ap, cmd);
 938                 call.arg.fl = *va_arg(ap, struct flock *);
 939                 va_end(ap);
 940                 break;
 941         default:
 942                 /* This means you need to implement it here. */
 943                 err(1, "failtest: unknown fcntl %u", cmd);
 944         }
 945
 946         p = add_history(FAILTEST_FCNTL, file, line, &call);
 947         get_locks();
 948
 949         if (should_fail(p)) {
 950                 p->u.fcntl.ret = -1;
 951                 if (p->u.fcntl.cmd == F_SETLK)
 952                         p->error = EAGAIN;
 953                 else
 954                         p->error = EDEADLK;
 955         } else {
 956                 p->u.fcntl.ret = fcntl(p->u.fcntl.fd, p->u.fcntl.cmd,
 957                                        &p->u.fcntl.arg.fl);
 958                 if (p->u.fcntl.ret == -1)
 959                         p->error = errno;
 960                 else {
 961                         /* We don't handle anything else yet. */
 962                         assert(p->u.fcntl.arg.fl.l_whence == SEEK_SET);
 963                         locks = add_lock(locks,
 964                                          p->u.fcntl.fd,
 965                                          p->u.fcntl.arg.fl.l_start,
 966                                          end_of(p->u.fcntl.arg.fl.l_start,
 967                                                 p->u.fcntl.arg.fl.l_len),
 968                                          p->u.fcntl.arg.fl.l_type);
 969                 }
 970         }
 971         errno = p->error;
 972         return p->u.fcntl.ret;
 973 }
 974
 975 void failtest_init(int argc, char *argv[])
 976 {
 977         unsigned int i;
 978
 979         for (i = 1; i < argc; i++) {
 980                 if (!strncmp(argv[i], "--failpath=", strlen("--failpath="))) {
 981                         failpath = argv[i] + strlen("--failpath=");
 982                 } else if (strcmp(argv[i], "--tracepath") == 0) {
 983                         tracefd = dup(STDERR_FILENO);
 984                         failtest_timeout_ms = -1;
 985                 }
 986         }
 987         gettimeofday(&start, NULL);
 988 }
 989
 990 /* Free up memory, so valgrind doesn't report leaks. */
 991 static void free_everything(void)
 992 {
 993         unsigned int i;
 994
 995         /* We don't do this in cleanup: needed even for failed opens. */
 996         for (i = 0; i < history_num; i++) {
 997                 if (history[i].type == FAILTEST_OPEN)
 998                         free((char *)history[i].u.open.pathname);
 999         }
1000         free(history);
1001 }
1002
1003 void failtest_exit(int status)
1004 {
1005         int i;
1006
1007         if (control_fd == -1) {
1008                 free_everything();
1009                 exit(status);
1010         }
1011
1012         if (failtest_exit_check) {
1013                 if (!failtest_exit_check(history, history_num))
1014                         child_fail(NULL, 0, "failtest_exit_check failed\n");
1015         }
1016
1017         /* Cleanup everything, in reverse order. */
1018         for (i = history_num - 1; i >= 0; i--)
1019                 if (history[i].cleanup)
1020                         history[i].cleanup(&history[i].u);
1021
1022         free_everything();
1023         tell_parent(SUCCESS);
1024         exit(0);
1025 }