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