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

   1 /* Licensed under LGPL - see LICENSE file for details */
   2 #include "config.h"
   3 #include <stdarg.h>
   4 #include <string.h>
   5 #include <stdio.h>
   6 #include <stdarg.h>
   7 #include <ctype.h>
   8 #include <err.h>
   9 #include <unistd.h>
  10 #include <poll.h>
  11 #include <errno.h>
  12 #include <sys/types.h>
  13 #include <sys/wait.h>
  14 #include <sys/stat.h>
  15 #include <sys/time.h>
  16 #include <signal.h>
  17 #include <assert.h>
  18 #include <ccan/read_write_all/read_write_all.h>
  19 #include <ccan/failtest/failtest_proto.h>
  20 #include <ccan/failtest/failtest.h>
  21 #include <ccan/build_assert/build_assert.h>
  22
  23 enum failtest_result (*failtest_hook)(struct failtest_call *, unsigned);
  24
  25 static int tracefd = -1;
  26
  27 unsigned int failtest_timeout_ms = 20000;
  28
  29 const char *failpath;
  30 const char *debugpath;
  31
  32 enum info_type {
  33         WRITE,
  34         RELEASE_LOCKS,
  35         FAILURE,
  36         SUCCESS,
  37         UNEXPECTED
  38 };
  39
  40 struct lock_info {
  41         int fd;
  42         /* end is inclusive: you can't have a 0-byte lock. */
  43         off_t start, end;
  44         int type;
  45 };
  46
  47 bool (*failtest_exit_check)(struct failtest_call *history, unsigned num);
  48
  49 static struct failtest_call *history = NULL;
  50 static unsigned int history_num = 0;
  51 static int control_fd = -1;
  52 static struct timeval start;
  53 static unsigned int probe_count = 0;
  54
  55 static struct write_call *child_writes = NULL;
  56 static unsigned int child_writes_num = 0;
  57
  58 static pid_t lock_owner;
  59 static struct lock_info *locks = NULL;
  60 static unsigned int lock_num = 0;
  61
  62 static pid_t orig_pid;
  63
  64 static const char info_to_arg[] = "mceoxprwf";
  65
  66 /* Dummy call used for failtest_undo wrappers. */
  67 static struct failtest_call unrecorded_call;
  68
  69 static struct failtest_call *add_history_(enum failtest_call_type type,
  70                                           const char *file,
  71                                           unsigned int line,
  72                                           const void *elem,
  73                                           size_t elem_size)
  74 {
  75         /* NULL file is how we suppress failure. */
  76         if (!file)
  77                 return &unrecorded_call;
  78
  79         history = realloc(history, (history_num + 1) * sizeof(*history));
  80         history[history_num].type = type;
  81         history[history_num].file = file;
  82         history[history_num].line = line;
  83         history[history_num].cleanup = NULL;
  84         memcpy(&history[history_num].u, elem, elem_size);
  85         return &history[history_num++];
  86 }
  87
  88 #define add_history(type, file, line, elem) \
  89         add_history_((type), (file), (line), (elem), sizeof(*(elem)))
  90
  91 /* We do a fake call inside a sizeof(), to check types. */
  92 #define set_cleanup(call, clean, type)                  \
  93         (call)->cleanup = (void *)((void)sizeof(clean((type *)NULL),1), (clean))
  94
  95 static bool read_write_info(int fd)
  96 {
  97         struct write_call *w;
  98         char *buf;
  99
 100         /* We don't need all of this, but it's simple. */
 101         child_writes = realloc(child_writes,
 102                                (child_writes_num+1) * sizeof(child_writes[0]));
 103         w = &child_writes[child_writes_num];
 104         if (!read_all(fd, w, sizeof(*w)))
 105                 return false;
 106
 107         w->buf = buf = malloc(w->count);
 108         if (!read_all(fd, buf, w->count))
 109                 return false;
 110
 111         child_writes_num++;
 112         return true;
 113 }
 114
 115 static char *failpath_string(void)
 116 {
 117         unsigned int i;
 118         char *ret = malloc(history_num + 1);
 119
 120         for (i = 0; i < history_num; i++) {
 121                 ret[i] = info_to_arg[history[i].type];
 122                 if (history[i].fail)
 123                         ret[i] = toupper(ret[i]);
 124         }
 125         ret[i] = '\0';
 126         return ret;
 127 }
 128
 129 static void tell_parent(enum info_type type)
 130 {
 131         if (control_fd != -1)
 132                 write_all(control_fd, &type, sizeof(type));
 133 }
 134
 135 static void child_fail(const char *out, size_t outlen, const char *fmt, ...)
 136 {
 137         va_list ap;
 138         char *path = failpath_string();
 139
 140         va_start(ap, fmt);
 141         vfprintf(stderr, fmt, ap);
 142         va_end(ap);
 143
 144         fprintf(stderr, "%.*s", (int)outlen, out);
 145         printf("To reproduce: --failpath=%s\n", path);
 146         free(path);
 147         tell_parent(FAILURE);
 148         exit(1);
 149 }
 150
 151 static void trace(const char *fmt, ...)
 152 {
 153         va_list ap;
 154
 155         if (tracefd == -1)
 156                 return;
 157
 158         va_start(ap, fmt);
 159         vdprintf(tracefd, fmt, ap);
 160         va_end(ap);
 161 }
 162
 163 static pid_t child;
 164
 165 static void hand_down(int signum)
 166 {
 167         kill(child, signum);
 168 }
 169
 170 static void release_locks(void)
 171 {
 172         /* Locks were never acquired/reacquired? */
 173         if (lock_owner == 0)
 174                 return;
 175
 176         /* We own them?  Release them all. */
 177         if (lock_owner == getpid()) {
 178                 unsigned int i;
 179                 struct flock fl;
 180                 fl.l_type = F_UNLCK;
 181                 fl.l_whence = SEEK_SET;
 182                 fl.l_start = 0;
 183                 fl.l_len = 0;
 184
 185                 for (i = 0; i < lock_num; i++)
 186                         fcntl(locks[i].fd, F_SETLK, &fl);
 187         } else {
 188                 /* Our parent must have them; pass request up. */
 189                 enum info_type type = RELEASE_LOCKS;
 190                 assert(control_fd != -1);
 191                 write_all(control_fd, &type, sizeof(type));
 192         }
 193         lock_owner = 0;
 194 }
 195
 196 /* off_t is a signed type.  Getting its max is non-trivial. */
 197 static off_t off_max(void)
 198 {
 199         BUILD_ASSERT(sizeof(off_t) == 4 || sizeof(off_t) == 8);
 200         if (sizeof(off_t) == 4)
 201                 return (off_t)0x7FFFFFF;
 202         else
 203                 return (off_t)0x7FFFFFFFFFFFFFFULL;
 204 }
 205
 206 static void get_locks(void)
 207 {
 208         unsigned int i;
 209         struct flock fl;
 210
 211         if (lock_owner == getpid())
 212                 return;
 213
 214         if (lock_owner != 0) {
 215                 enum info_type type = RELEASE_LOCKS;
 216                 assert(control_fd != -1);
 217                 write_all(control_fd, &type, sizeof(type));
 218         }
 219
 220         fl.l_whence = SEEK_SET;
 221
 222         for (i = 0; i < lock_num; i++) {
 223                 fl.l_type = locks[i].type;
 224                 fl.l_start = locks[i].start;
 225                 if (locks[i].end == off_max())
 226                         fl.l_len = 0;
 227                 else
 228                         fl.l_len = locks[i].end - locks[i].start + 1;
 229
 230                 if (fcntl(locks[i].fd, F_SETLKW, &fl) != 0)
 231                         abort();
 232         }
 233         lock_owner = getpid();
 234 }
 235
 236 struct saved_file {
 237         struct saved_file *next;
 238         int fd;
 239         void *contents;
 240         off_t off, len;
 241 };
 242
 243 static struct saved_file *save_file(struct saved_file *next, int fd)
 244 {
 245         struct saved_file *s = malloc(sizeof(*s));
 246
 247         s->next = next;
 248         s->fd = fd;
 249         s->off = lseek(fd, 0, SEEK_CUR);
 250         /* Special file?  Erk... */
 251         assert(s->off != -1);
 252         s->len = lseek(fd, 0, SEEK_END);
 253         lseek(fd, 0, SEEK_SET);
 254         s->contents = malloc(s->len);
 255         if (read(fd, s->contents, s->len) != s->len)
 256                 err(1, "Failed to save %zu bytes", (size_t)s->len);
 257         lseek(fd, s->off, SEEK_SET);
 258         return s;
 259 }
 260
 261 /* We have little choice but to save and restore open files: mmap means we
 262  * can really intercept changes in the child.
 263  *
 264  * We could do non-mmap'ed files on demand, however. */
 265 static struct saved_file *save_files(void)
 266 {
 267         struct saved_file *files = NULL;
 268         int i;
 269
 270         /* Figure out the set of live fds. */
 271         for (i = history_num - 2; i >= 0; i--) {
 272                 if (history[i].type == FAILTEST_OPEN) {
 273                         int fd = history[i].u.open.ret;
 274                         /* Only do successful, writable fds. */
 275                         if (fd < 0)
 276                                 continue;
 277
 278                         /* If it was closed, cleanup == NULL. */
 279                         if (!history[i].cleanup)
 280                                 continue;
 281
 282                         if ((history[i].u.open.flags & O_RDWR) == O_RDWR) {
 283                                 files = save_file(files, fd);
 284                         } else if ((history[i].u.open.flags & O_WRONLY)
 285                                    == O_WRONLY) {
 286                                 /* FIXME: Handle O_WRONLY.  Open with O_RDWR? */
 287                                 abort();
 288                         }
 289                 }
 290         }
 291
 292         return files;
 293 }
 294
 295 static void restore_files(struct saved_file *s)
 296 {
 297         while (s) {
 298                 struct saved_file *next = s->next;
 299
 300                 lseek(s->fd, 0, SEEK_SET);
 301                 if (write(s->fd, s->contents, s->len) != s->len)
 302                         err(1, "Failed to restore %zu bytes", (size_t)s->len);
 303                 if (ftruncate(s->fd, s->len) != 0)
 304                         err(1, "Failed to trim file to length %zu",
 305                             (size_t)s->len);
 306                 free(s->contents);
 307                 lseek(s->fd, s->off, SEEK_SET);
 308                 free(s);
 309                 s = next;
 310         }
 311 }
 312
 313 /* Free up memory, so valgrind doesn't report leaks. */
 314 static void free_everything(void)
 315 {
 316         unsigned int i;
 317
 318         /* We don't do this in cleanup: needed even for failed opens. */
 319         for (i = 0; i < history_num; i++) {
 320                 if (history[i].type == FAILTEST_OPEN)
 321                         free((char *)history[i].u.open.pathname);
 322         }
 323         free(history);
 324 }
 325
 326 static NORETURN void failtest_cleanup(bool forced_cleanup, int status)
 327 {
 328         int i;
 329
 330         /* For children, we don't care if they "failed" the testing. */
 331         if (control_fd != -1)
 332                 status = 0;
 333
 334         if (forced_cleanup)
 335                 history_num--;
 336
 337         /* Cleanup everything, in reverse order. */
 338         for (i = history_num - 1; i >= 0; i--) {
 339                 if (!history[i].cleanup)
 340                         continue;
 341                 if (!forced_cleanup) {
 342                         printf("Leak at %s:%u: --failpath=%s\n",
 343                                history[i].file, history[i].line,
 344                                failpath_string());
 345                         status = 1;
 346                 }
 347                 history[i].cleanup(&history[i].u);
 348         }
 349
 350         free_everything();
 351         tell_parent(SUCCESS);
 352         exit(status);
 353 }
 354
 355 static bool should_fail(struct failtest_call *call)
 356 {
 357         int status;
 358         int control[2], output[2];
 359         enum info_type type = UNEXPECTED;
 360         char *out = NULL;
 361         size_t outlen = 0;
 362         struct saved_file *files;
 363
 364         /* Are we probing? */
 365         if (probe_count && --probe_count == 0 && control_fd != -1)
 366                 failtest_cleanup(true, 0);
 367
 368         if (call == &unrecorded_call)
 369                 return false;
 370
 371         if (failpath) {
 372                 /* + means continue after end, like normal. */
 373                 if (*failpath == '+')
 374                         failpath = NULL;
 375                 else if (*failpath == '\0') {
 376                         /* Continue, but don't inject errors. */
 377                         return call->fail = false;
 378                 } else {
 379                         if (tolower((unsigned char)*failpath)
 380                             != info_to_arg[call->type])
 381                                 errx(1, "Failpath expected '%c' got '%c'\n",
 382                                      info_to_arg[call->type], *failpath);
 383                         call->fail = isupper((unsigned char)*(failpath++));
 384                         return call->fail;
 385                 }
 386         }
 387
 388         /* Attach debugger if they asked for it. */
 389         if (debugpath && history_num == strlen(debugpath)) {
 390                 unsigned int i;
 391
 392                 for (i = 0; i < history_num; i++) {
 393                         unsigned char c = info_to_arg[history[i].type];
 394                         if (history[i].fail)
 395                                 c = toupper(c);
 396                         if (c != debugpath[i])
 397                                 break;
 398                 }
 399                 if (i == history_num) {
 400                         char str[80];
 401
 402                         /* Don't timeout. */
 403                         signal(SIGUSR1, SIG_IGN);
 404                         sprintf(str, "xterm -e gdb /proc/%d/exe %d &",
 405                                 getpid(), getpid());
 406                         if (system(str) == 0)
 407                                 sleep(5);
 408                 }
 409         }
 410
 411         if (failtest_hook) {
 412                 switch (failtest_hook(history, history_num)) {
 413                 case FAIL_OK:
 414                         break;
 415                 case FAIL_PROBE:
 416                         /* Already down probe path?  Stop now. */
 417                         if (!probe_count) {
 418                                 /* FIXME: We should run *parent* and
 419                                  * run probe until calls match up again. */
 420                                 probe_count = 3;
 421                                 break;
 422                         } else {
 423                                 /* Child should give up now. */
 424                                 if (control_fd != -1)
 425                                         failtest_cleanup(true, 0);
 426                                 /* Parent, don't fail again. */
 427                         }
 428                 case FAIL_DONT_FAIL:
 429                         call->fail = false;
 430                         return false;
 431                 default:
 432                         abort();
 433                 }
 434         }
 435
 436         files = save_files();
 437
 438         /* We're going to fail in the child. */
 439         call->fail = true;
 440         if (pipe(control) != 0 || pipe(output) != 0)
 441                 err(1, "opening pipe");
 442
 443         /* Prevent double-printing (in child and parent) */
 444         fflush(stdout);
 445         child = fork();
 446         if (child == -1)
 447                 err(1, "forking failed");
 448
 449         if (child == 0) {
 450                 if (tracefd != -1) {
 451                         struct timeval now;
 452                         const char *p;
 453                         gettimeofday(&now, NULL);
 454                         if (now.tv_usec < start.tv_usec) {
 455                                 now.tv_sec--;
 456                                 now.tv_usec += 1000000;
 457                         }
 458                         now.tv_usec -= start.tv_usec;
 459                         now.tv_sec -= start.tv_sec;
 460                         p = failpath_string();
 461                         trace("%u->%u (%u.%02u): %s (", getppid(), getpid(),
 462                               (int)now.tv_sec, (int)now.tv_usec / 10000, p);
 463                         free((char *)p);
 464                         p = strrchr(history[history_num-1].file, '/');
 465                         if (p)
 466                                 trace("%s", p+1);
 467                         else
 468                                 trace("%s", history[history_num-1].file);
 469                         trace(":%u)\n", history[history_num-1].line);
 470                 }
 471                 close(control[0]);
 472                 close(output[0]);
 473                 dup2(output[1], STDOUT_FILENO);
 474                 dup2(output[1], STDERR_FILENO);
 475                 if (output[1] != STDOUT_FILENO && output[1] != STDERR_FILENO)
 476                         close(output[1]);
 477                 control_fd = control[1];
 478                 return true;
 479         }
 480
 481         signal(SIGUSR1, hand_down);
 482
 483         close(control[1]);
 484         close(output[1]);
 485
 486         /* We grab output so we can display it; we grab writes so we
 487          * can compare. */
 488         do {
 489                 struct pollfd pfd[2];
 490                 int ret;
 491
 492                 pfd[0].fd = output[0];
 493                 pfd[0].events = POLLIN|POLLHUP;
 494                 pfd[1].fd = control[0];
 495                 pfd[1].events = POLLIN|POLLHUP;
 496
 497                 if (type == SUCCESS)
 498                         ret = poll(pfd, 1, failtest_timeout_ms);
 499                 else
 500                         ret = poll(pfd, 2, failtest_timeout_ms);
 501
 502                 if (ret == 0)
 503                         hand_down(SIGUSR1);
 504                 if (ret < 0) {
 505                         if (errno == EINTR)
 506                                 continue;
 507                         err(1, "Poll returned %i", ret);
 508                 }
 509
 510                 if (pfd[0].revents & POLLIN) {
 511                         ssize_t len;
 512
 513                         out = realloc(out, outlen + 8192);
 514                         len = read(output[0], out + outlen, 8192);
 515                         outlen += len;
 516                 } else if (type != SUCCESS && (pfd[1].revents & POLLIN)) {
 517                         if (read_all(control[0], &type, sizeof(type))) {
 518                                 if (type == WRITE) {
 519                                         if (!read_write_info(control[0]))
 520                                                 break;
 521                                 } else if (type == RELEASE_LOCKS) {
 522                                         release_locks();
 523                                         /* FIXME: Tell them we're done... */
 524                                 }
 525                         }
 526                 } else if (pfd[0].revents & POLLHUP) {
 527                         break;
 528                 }
 529         } while (type != FAILURE);
 530
 531         close(output[0]);
 532         close(control[0]);
 533         waitpid(child, &status, 0);
 534         if (!WIFEXITED(status)) {
 535                 if (WTERMSIG(status) == SIGUSR1)
 536                         child_fail(out, outlen, "Timed out");
 537                 else
 538                         child_fail(out, outlen, "Killed by signal %u: ",
 539                                    WTERMSIG(status));
 540         }
 541         /* Child printed failure already, just pass up exit code. */
 542         if (type == FAILURE) {
 543                 fprintf(stderr, "%.*s", (int)outlen, out);
 544                 tell_parent(type);
 545                 exit(WEXITSTATUS(status) ? WEXITSTATUS(status) : 1);
 546         }
 547         if (WEXITSTATUS(status) != 0)
 548                 child_fail(out, outlen, "Exited with status %i: ",
 549                            WEXITSTATUS(status));
 550
 551         free(out);
 552         signal(SIGUSR1, SIG_DFL);
 553
 554         restore_files(files);
 555
 556         /* We continue onwards without failing. */
 557         call->fail = false;
 558         return false;
 559 }
 560
 561 static void cleanup_calloc(struct calloc_call *call)
 562 {
 563         free(call->ret);
 564 }
 565
 566 void *failtest_calloc(size_t nmemb, size_t size,
 567                       const char *file, unsigned line)
 568 {
 569         struct failtest_call *p;
 570         struct calloc_call call;
 571         call.nmemb = nmemb;
 572         call.size = size;
 573         p = add_history(FAILTEST_CALLOC, file, line, &call);
 574
 575         if (should_fail(p)) {
 576                 p->u.calloc.ret = NULL;
 577                 p->error = ENOMEM;
 578         } else {
 579                 p->u.calloc.ret = calloc(nmemb, size);
 580                 set_cleanup(p, cleanup_calloc, struct calloc_call);
 581         }
 582         errno = p->error;
 583         return p->u.calloc.ret;
 584 }
 585
 586 static void cleanup_malloc(struct malloc_call *call)
 587 {
 588         free(call->ret);
 589 }
 590
 591 void *failtest_malloc(size_t size, const char *file, unsigned line)
 592 {
 593         struct failtest_call *p;
 594         struct malloc_call call;
 595         call.size = size;
 596
 597         p = add_history(FAILTEST_MALLOC, file, line, &call);
 598         if (should_fail(p)) {
 599                 p->u.calloc.ret = NULL;
 600                 p->error = ENOMEM;
 601         } else {
 602                 p->u.calloc.ret = malloc(size);
 603                 set_cleanup(p, cleanup_malloc, struct malloc_call);
 604         }
 605         errno = p->error;
 606         return p->u.calloc.ret;
 607 }
 608
 609 static void cleanup_realloc(struct realloc_call *call)
 610 {
 611         free(call->ret);
 612 }
 613
 614 /* Walk back and find out if we got this ptr from a previous routine. */
 615 static void fixup_ptr_history(void *ptr, unsigned int last)
 616 {
 617         int i;
 618
 619         /* Start at end of history, work back. */
 620         for (i = last - 1; i >= 0; i--) {
 621                 switch (history[i].type) {
 622                 case FAILTEST_REALLOC:
 623                         if (history[i].u.realloc.ret == ptr) {
 624                                 history[i].cleanup = NULL;
 625                                 return;
 626                         }
 627                         break;
 628                 case FAILTEST_MALLOC:
 629                         if (history[i].u.malloc.ret == ptr) {
 630                                 history[i].cleanup = NULL;
 631                                 return;
 632                         }
 633                         break;
 634                 case FAILTEST_CALLOC:
 635                         if (history[i].u.calloc.ret == ptr) {
 636                                 history[i].cleanup = NULL;
 637                                 return;
 638                         }
 639                         break;
 640                 default:
 641                         break;
 642                 }
 643         }
 644 }
 645
 646 void *failtest_realloc(void *ptr, size_t size, const char *file, unsigned line)
 647 {
 648         struct failtest_call *p;
 649         struct realloc_call call;
 650         call.size = size;
 651         p = add_history(FAILTEST_REALLOC, file, line, &call);
 652
 653         /* FIXME: Try one child moving allocation, one not. */
 654         if (should_fail(p)) {
 655                 p->u.realloc.ret = NULL;
 656                 p->error = ENOMEM;
 657         } else {
 658                 fixup_ptr_history(ptr, history_num-1);
 659                 p->u.realloc.ret = realloc(ptr, size);
 660                 set_cleanup(p, cleanup_realloc, struct realloc_call);
 661         }
 662         errno = p->error;
 663         return p->u.realloc.ret;
 664 }
 665
 666 void failtest_free(void *ptr)
 667 {
 668         fixup_ptr_history(ptr, history_num);
 669         free(ptr);
 670 }
 671
 672 static void cleanup_open(struct open_call *call)
 673 {
 674         close(call->ret);
 675 }
 676
 677 int failtest_open(const char *pathname,
 678                   const char *file, unsigned line, ...)
 679 {
 680         struct failtest_call *p;
 681         struct open_call call;
 682         va_list ap;
 683
 684         call.pathname = strdup(pathname);
 685         va_start(ap, line);
 686         call.flags = va_arg(ap, int);
 687         if (call.flags & O_CREAT) {
 688                 call.mode = va_arg(ap, int);
 689                 va_end(ap);
 690         }
 691         p = add_history(FAILTEST_OPEN, file, line, &call);
 692         /* Avoid memory leak! */
 693         if (p == &unrecorded_call)
 694                 free((char *)call.pathname);
 695         p->u.open.ret = open(pathname, call.flags, call.mode);
 696
 697         if (!failpath && p->u.open.ret == -1) {
 698                 p->fail = false;
 699                 p->error = errno;
 700         } else if (should_fail(p)) {
 701                 close(p->u.open.ret);
 702                 p->u.open.ret = -1;
 703                 /* FIXME: Play with error codes? */
 704                 p->error = EACCES;
 705         } else {
 706                 set_cleanup(p, cleanup_open, struct open_call);
 707         }
 708         errno = p->error;
 709         return p->u.open.ret;
 710 }
 711
 712 static void cleanup_pipe(struct pipe_call *call)
 713 {
 714         if (!call->closed[0])
 715                 close(call->fds[0]);
 716         if (!call->closed[1])
 717                 close(call->fds[1]);
 718 }
 719
 720 int failtest_pipe(int pipefd[2], const char *file, unsigned line)
 721 {
 722         struct failtest_call *p;
 723         struct pipe_call call;
 724
 725         p = add_history(FAILTEST_PIPE, file, line, &call);
 726         if (should_fail(p)) {
 727                 p->u.open.ret = -1;
 728                 /* FIXME: Play with error codes? */
 729                 p->error = EMFILE;
 730         } else {
 731                 p->u.pipe.ret = pipe(p->u.pipe.fds);
 732                 p->u.pipe.closed[0] = p->u.pipe.closed[1] = false;
 733                 set_cleanup(p, cleanup_pipe, struct pipe_call);
 734         }
 735         /* This causes valgrind to notice if they use pipefd[] after failure */
 736         memcpy(pipefd, p->u.pipe.fds, sizeof(p->u.pipe.fds));
 737         errno = p->error;
 738         return p->u.pipe.ret;
 739 }
 740
 741 ssize_t failtest_pread(int fd, void *buf, size_t count, off_t off,
 742                        const char *file, unsigned line)
 743 {
 744         struct failtest_call *p;
 745         struct read_call call;
 746         call.fd = fd;
 747         call.buf = buf;
 748         call.count = count;
 749         call.off = off;
 750         p = add_history(FAILTEST_READ, file, line, &call);
 751
 752         /* FIXME: Try partial read returns. */
 753         if (should_fail(p)) {
 754                 p->u.read.ret = -1;
 755                 p->error = EIO;
 756         } else {
 757                 p->u.read.ret = pread(fd, buf, count, off);
 758         }
 759         errno = p->error;
 760         return p->u.read.ret;
 761 }
 762
 763 ssize_t failtest_pwrite(int fd, const void *buf, size_t count, off_t off,
 764                         const char *file, unsigned line)
 765 {
 766         struct failtest_call *p;
 767         struct write_call call;
 768
 769         call.fd = fd;
 770         call.buf = buf;
 771         call.count = count;
 772         call.off = off;
 773         p = add_history(FAILTEST_WRITE, file, line, &call);
 774
 775         /* If we're a child, we need to make sure we write the same thing
 776          * to non-files as the parent does, so tell it. */
 777         if (control_fd != -1 && off == (off_t)-1) {
 778                 enum info_type type = WRITE;
 779
 780                 write_all(control_fd, &type, sizeof(type));
 781                 write_all(control_fd, &p->u.write, sizeof(p->u.write));
 782                 write_all(control_fd, buf, count);
 783         }
 784
 785         /* FIXME: Try partial write returns. */
 786         if (should_fail(p)) {
 787                 p->u.write.ret = -1;
 788                 p->error = EIO;
 789         } else {
 790                 /* FIXME: We assume same write order in parent and child */
 791                 if (off == (off_t)-1 && child_writes_num != 0) {
 792                         if (child_writes[0].fd != fd)
 793                                 errx(1, "Child wrote to fd %u, not %u?",
 794                                      child_writes[0].fd, fd);
 795                         if (child_writes[0].off != p->u.write.off)
 796                                 errx(1, "Child wrote to offset %zu, not %zu?",
 797                                      (size_t)child_writes[0].off,
 798                                      (size_t)p->u.write.off);
 799                         if (child_writes[0].count != count)
 800                                 errx(1, "Child wrote length %zu, not %zu?",
 801                                      child_writes[0].count, count);
 802                         if (memcmp(child_writes[0].buf, buf, count)) {
 803                                 child_fail(NULL, 0,
 804                                            "Child wrote differently to"
 805                                            " fd %u than we did!\n", fd);
 806                         }
 807                         free((char *)child_writes[0].buf);
 808                         child_writes_num--;
 809                         memmove(&child_writes[0], &child_writes[1],
 810                                 sizeof(child_writes[0]) * child_writes_num);
 811
 812                         /* Is this is a socket or pipe, child wrote it
 813                            already. */
 814                         if (p->u.write.off == (off_t)-1) {
 815                                 p->u.write.ret = count;
 816                                 errno = p->error;
 817                                 return p->u.write.ret;
 818                         }
 819                 }
 820                 p->u.write.ret = pwrite(fd, buf, count, off);
 821         }
 822         errno = p->error;
 823         return p->u.write.ret;
 824 }
 825
 826 ssize_t failtest_read(int fd, void *buf, size_t count,
 827                       const char *file, unsigned line)
 828 {
 829         return failtest_pread(fd, buf, count, lseek(fd, 0, SEEK_CUR),
 830                               file, line);
 831 }
 832
 833 ssize_t failtest_write(int fd, const void *buf, size_t count,
 834                        const char *file, unsigned line)
 835 {
 836         return failtest_pwrite(fd, buf, count, lseek(fd, 0, SEEK_CUR),
 837                                file, line);
 838 }
 839
 840 static struct lock_info *WARN_UNUSED_RESULT
 841 add_lock(struct lock_info *locks, int fd, off_t start, off_t end, int type)
 842 {
 843         unsigned int i;
 844         struct lock_info *l;
 845
 846         for (i = 0; i < lock_num; i++) {
 847                 l = &locks[i];
 848
 849                 if (l->fd != fd)
 850                         continue;
 851                 /* Four cases we care about:
 852                  * Start overlap:
 853                  *      l =    |      |
 854                  *      new = |   |
 855                  * Mid overlap:
 856                  *      l =    |      |
 857                  *      new =    |  |
 858                  * End overlap:
 859                  *      l =    |      |
 860                  *      new =      |    |
 861                  * Total overlap:
 862                  *      l =    |      |
 863                  *      new = |         |
 864                  */
 865                 if (start > l->start && end < l->end) {
 866                         /* Mid overlap: trim entry, add new one. */
 867                         off_t new_start, new_end;
 868                         new_start = end + 1;
 869                         new_end = l->end;
 870                         l->end = start - 1;
 871                         locks = add_lock(locks,
 872                                          fd, new_start, new_end, l->type);
 873                         l = &locks[i];
 874                 } else if (start <= l->start && end >= l->end) {
 875                         /* Total overlap: eliminate entry. */
 876                         l->end = 0;
 877                         l->start = 1;
 878                 } else if (end >= l->start && end < l->end) {
 879                         /* Start overlap: trim entry. */
 880                         l->start = end + 1;
 881                 } else if (start > l->start && start <= l->end) {
 882                         /* End overlap: trim entry. */
 883                         l->end = start-1;
 884                 }
 885                 /* Nothing left?  Remove it. */
 886                 if (l->end < l->start) {
 887                         memmove(l, l + 1, (--lock_num - i) * sizeof(l[0]));
 888                         i--;
 889                 }
 890         }
 891
 892         if (type != F_UNLCK) {
 893                 locks = realloc(locks, (lock_num + 1) * sizeof(*locks));
 894                 l = &locks[lock_num++];
 895                 l->fd = fd;
 896                 l->start = start;
 897                 l->end = end;
 898                 l->type = type;
 899         }
 900         return locks;
 901 }
 902
 903 /* We trap this so we can record it: we don't fail it. */
 904 int failtest_close(int fd, const char *file, unsigned line)
 905 {
 906         int i;
 907         struct close_call call;
 908         struct failtest_call *p;
 909
 910         call.fd = fd;
 911         p = add_history(FAILTEST_CLOSE, file, line, &call);
 912         p->fail = false;
 913
 914         /* Consume close from failpath. */
 915         if (failpath)
 916                 if (should_fail(p))
 917                         abort();
 918
 919         if (fd < 0)
 920                 return close(fd);
 921
 922         /* Trace history to find source of fd. */
 923         for (i = history_num-1; i >= 0; i--) {
 924                 switch (history[i].type) {
 925                 case FAILTEST_PIPE:
 926                         /* From a pipe? */
 927                         if (history[i].u.pipe.fds[0] == fd) {
 928                                 assert(!history[i].u.pipe.closed[0]);
 929                                 history[i].u.pipe.closed[0] = true;
 930                                 if (history[i].u.pipe.closed[1])
 931                                         history[i].cleanup = NULL;
 932                                 goto out;
 933                         }
 934                         if (history[i].u.pipe.fds[1] == fd) {
 935                                 assert(!history[i].u.pipe.closed[1]);
 936                                 history[i].u.pipe.closed[1] = true;
 937                                 if (history[i].u.pipe.closed[0])
 938                                         history[i].cleanup = NULL;
 939                                 goto out;
 940                         }
 941                         break;
 942                 case FAILTEST_OPEN:
 943                         if (history[i].u.open.ret == fd) {
 944                                 assert((void *)history[i].cleanup
 945                                        == (void *)cleanup_open);
 946                                 history[i].cleanup = NULL;
 947                                 goto out;
 948                         }
 949                         break;
 950                 default:
 951                         break;
 952                 }
 953         }
 954
 955 out:
 956         locks = add_lock(locks, fd, 0, off_max(), F_UNLCK);
 957         return close(fd);
 958 }
 959
 960 /* Zero length means "to end of file" */
 961 static off_t end_of(off_t start, off_t len)
 962 {
 963         if (len == 0)
 964                 return off_max();
 965         return start + len - 1;
 966 }
 967
 968 /* FIXME: This only handles locks, really. */
 969 int failtest_fcntl(int fd, const char *file, unsigned line, int cmd, ...)
 970 {
 971         struct failtest_call *p;
 972         struct fcntl_call call;
 973         va_list ap;
 974
 975         call.fd = fd;
 976         call.cmd = cmd;
 977
 978         /* Argument extraction. */
 979         switch (cmd) {
 980         case F_SETFL:
 981         case F_SETFD:
 982                 va_start(ap, cmd);
 983                 call.arg.l = va_arg(ap, long);
 984                 va_end(ap);
 985                 return fcntl(fd, cmd, call.arg.l);
 986         case F_GETFD:
 987         case F_GETFL:
 988                 return fcntl(fd, cmd);
 989         case F_GETLK:
 990                 get_locks();
 991                 va_start(ap, cmd);
 992                 call.arg.fl = *va_arg(ap, struct flock *);
 993                 va_end(ap);
 994                 return fcntl(fd, cmd, &call.arg.fl);
 995         case F_SETLK:
 996         case F_SETLKW:
 997                 va_start(ap, cmd);
 998                 call.arg.fl = *va_arg(ap, struct flock *);
 999                 va_end(ap);
1000                 break;
1001         default:
1002                 /* This means you need to implement it here. */
1003                 err(1, "failtest: unknown fcntl %u", cmd);
1004         }
1005
1006         p = add_history(FAILTEST_FCNTL, file, line, &call);
1007
1008         if (should_fail(p)) {
1009                 p->u.fcntl.ret = -1;
1010                 if (p->u.fcntl.cmd == F_SETLK)
1011                         p->error = EAGAIN;
1012                 else
1013                         p->error = EDEADLK;
1014         } else {
1015                 get_locks();
1016                 p->u.fcntl.ret = fcntl(p->u.fcntl.fd, p->u.fcntl.cmd,
1017                                        &p->u.fcntl.arg.fl);
1018                 if (p->u.fcntl.ret == -1)
1019                         p->error = errno;
1020                 else {
1021                         /* We don't handle anything else yet. */
1022                         assert(p->u.fcntl.arg.fl.l_whence == SEEK_SET);
1023                         locks = add_lock(locks,
1024                                          p->u.fcntl.fd,
1025                                          p->u.fcntl.arg.fl.l_start,
1026                                          end_of(p->u.fcntl.arg.fl.l_start,
1027                                                 p->u.fcntl.arg.fl.l_len),
1028                                          p->u.fcntl.arg.fl.l_type);
1029                 }
1030         }
1031         errno = p->error;
1032         return p->u.fcntl.ret;
1033 }
1034
1035 pid_t failtest_getpid(const char *file, unsigned line)
1036 {
1037         /* You must call failtest_init first! */
1038         assert(orig_pid);
1039         return orig_pid;
1040 }
1041
1042 void failtest_init(int argc, char *argv[])
1043 {
1044         unsigned int i;
1045
1046         orig_pid = getpid();
1047
1048         for (i = 1; i < argc; i++) {
1049                 if (!strncmp(argv[i], "--failpath=", strlen("--failpath="))) {
1050                         failpath = argv[i] + strlen("--failpath=");
1051                 } else if (strcmp(argv[i], "--tracepath") == 0) {
1052                         tracefd = dup(STDERR_FILENO);
1053                         failtest_timeout_ms = -1;
1054                 } else if (!strncmp(argv[i], "--debugpath=",
1055                                     strlen("--debugpath="))) {
1056                         debugpath = argv[i] + strlen("--debugpath=");
1057                 }
1058         }
1059         gettimeofday(&start, NULL);
1060 }
1061
1062 bool failtest_has_failed(void)
1063 {
1064         return control_fd != -1;
1065 }
1066
1067 void failtest_exit(int status)
1068 {
1069         if (failtest_exit_check) {
1070                 if (!failtest_exit_check(history, history_num))
1071                         child_fail(NULL, 0, "failtest_exit_check failed\n");
1072         }
1073
1074         failtest_cleanup(false, status);
1075 }