xref: /netbsd-src/lib/librumpuser/rumpuser.c (revision a4ddc2c8fb9af816efe3b1c375a5530aef0e89e9)
1 /*	$NetBSD: rumpuser.c,v 1.29 2013/03/18 21:00:52 pooka Exp $	*/
2 
3 /*
4  * Copyright (c) 2007-2010 Antti Kantee.  All Rights Reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
16  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 #include "rumpuser_port.h"
29 
30 #if !defined(lint)
31 __RCSID("$NetBSD: rumpuser.c,v 1.29 2013/03/18 21:00:52 pooka Exp $");
32 #endif /* !lint */
33 
34 #include <sys/ioctl.h>
35 #include <sys/mman.h>
36 #include <sys/uio.h>
37 #include <sys/stat.h>
38 #include <sys/time.h>
39 
40 #ifdef __NetBSD__
41 #include <sys/disk.h>
42 #include <sys/disklabel.h>
43 #include <sys/dkio.h>
44 #include <sys/event.h>
45 #endif
46 
47 #if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__DragonFly__)
48 #include <sys/sysctl.h>
49 #endif
50 
51 #include <assert.h>
52 #include <errno.h>
53 #include <fcntl.h>
54 #include <netdb.h>
55 #include <poll.h>
56 #include <signal.h>
57 #include <stdarg.h>
58 #include <stdint.h>
59 #include <stdio.h>
60 #include <stdlib.h>
61 #include <string.h>
62 #include <time.h>
63 #include <unistd.h>
64 
65 #include <rump/rumpuser.h>
66 
67 #include "rumpuser_int.h"
68 
69 int
70 rumpuser_getversion(void)
71 {
72 
73 	return RUMPUSER_VERSION;
74 }
75 
76 int
77 rumpuser_getfileinfo(const char *path, uint64_t *sizep, int *ftp, int *error)
78 {
79 	struct stat sb;
80 	uint64_t size;
81 	int needsdev = 0, rv = 0, ft;
82 	int fd = -1;
83 
84 	if (stat(path, &sb) == -1) {
85 		seterror(errno);
86 		return -1;
87 	}
88 
89 	switch (sb.st_mode & S_IFMT) {
90 	case S_IFDIR:
91 		ft = RUMPUSER_FT_DIR;
92 		break;
93 	case S_IFREG:
94 		ft = RUMPUSER_FT_REG;
95 		break;
96 	case S_IFBLK:
97 		ft = RUMPUSER_FT_BLK;
98 		needsdev = 1;
99 		break;
100 	case S_IFCHR:
101 		ft = RUMPUSER_FT_CHR;
102 		needsdev = 1;
103 		break;
104 	default:
105 		ft = RUMPUSER_FT_OTHER;
106 		break;
107 	}
108 
109 	if (!needsdev) {
110 		size = sb.st_size;
111 	} else if (sizep) {
112 		/*
113 		 * Welcome to the jungle.  Of course querying the kernel
114 		 * for a device partition size is supposed to be far from
115 		 * trivial.  On NetBSD we use ioctl.  On $other platform
116 		 * we have a problem.  We try "the lseek trick" and just
117 		 * fail if that fails.  Platform specific code can later
118 		 * be written here if appropriate.
119 		 *
120 		 * On NetBSD we hope and pray that for block devices nobody
121 		 * else is holding them open, because otherwise the kernel
122 		 * will not permit us to open it.  Thankfully, this is
123 		 * usually called only in bootstrap and then we can
124 		 * forget about it.
125 		 */
126 #ifndef __NetBSD__
127 		off_t off;
128 
129 		fd = open(path, O_RDONLY);
130 		if (fd == -1) {
131 			seterror(errno);
132 			rv = -1;
133 			goto out;
134 		}
135 
136 		off = lseek(fd, 0, SEEK_END);
137 		if (off != 0) {
138 			size = off;
139 			goto out;
140 		}
141 		fprintf(stderr, "error: device size query not implemented on "
142 		    "this platform\n");
143 		seterror(EOPNOTSUPP);
144 		rv = -1;
145 		goto out;
146 #else
147 		struct disklabel lab;
148 		struct partition *parta;
149 		struct dkwedge_info dkw;
150 
151 		fd = open(path, O_RDONLY);
152 		if (fd == -1) {
153 			seterror(errno);
154 			rv = -1;
155 			goto out;
156 		}
157 
158 		if (ioctl(fd, DIOCGDINFO, &lab) == 0) {
159 			parta = &lab.d_partitions[DISKPART(sb.st_rdev)];
160 			size = (uint64_t)lab.d_secsize * parta->p_size;
161 			goto out;
162 		}
163 
164 		if (ioctl(fd, DIOCGWEDGEINFO, &dkw) == 0) {
165 			/*
166 			 * XXX: should use DIOCGDISKINFO to query
167 			 * sector size, but that requires proplib,
168 			 * so just don't bother for now.  it's nice
169 			 * that something as difficult as figuring out
170 			 * a partition's size has been made so easy.
171 			 */
172 			size = dkw.dkw_size << DEV_BSHIFT;
173 			goto out;
174 		}
175 
176 		seterror(errno);
177 		rv = -1;
178 #endif /* __NetBSD__ */
179 	}
180 
181  out:
182 	if (rv == 0 && sizep)
183 		*sizep = size;
184 	if (rv == 0 && ftp)
185 		*ftp = ft;
186 	if (fd != -1)
187 		close(fd);
188 
189 	return rv;
190 }
191 
192 int
193 rumpuser_nanosleep(uint64_t *sec, uint64_t *nsec, int *error)
194 {
195 	struct timespec rqt, rmt;
196 	int rv;
197 
198 	/*LINTED*/
199 	rqt.tv_sec = *sec;
200 	/*LINTED*/
201 	rqt.tv_nsec = *nsec;
202 
203 	KLOCK_WRAP(rv = nanosleep(&rqt, &rmt));
204 	if (rv == -1)
205 		seterror(errno);
206 
207 	*sec = rmt.tv_sec;
208 	*nsec = rmt.tv_nsec;
209 
210 	return rv;
211 }
212 
213 void *
214 rumpuser_malloc(size_t howmuch, int alignment)
215 {
216 	void *mem;
217 	int rv;
218 
219 	if (alignment == 0)
220 		alignment = sizeof(void *);
221 
222 	rv = posix_memalign(&mem, (size_t)alignment, howmuch);
223 	if (__predict_false(rv != 0)) {
224 		if (rv == EINVAL) {
225 			printf("rumpuser_malloc: invalid alignment %d\n",
226 			    alignment);
227 			abort();
228 		}
229 		mem = NULL;
230 	}
231 
232 	return mem;
233 }
234 
235 void *
236 rumpuser_realloc(void *ptr, size_t howmuch)
237 {
238 
239 	return realloc(ptr, howmuch);
240 }
241 
242 void
243 rumpuser_free(void *ptr)
244 {
245 
246 	free(ptr);
247 }
248 
249 void *
250 rumpuser_anonmmap(void *prefaddr, size_t size, int alignbit,
251 	int exec, int *error)
252 {
253 	void *rv;
254 	int prot;
255 
256 #ifndef MAP_ALIGNED
257 #define MAP_ALIGNED(a) 0
258 	if (alignbit)
259 		fprintf(stderr, "rumpuser_anonmmap: warning, requested "
260 		    "alignment not supported by hypervisor\n");
261 #endif
262 
263 	prot = PROT_READ|PROT_WRITE;
264 	if (exec)
265 		prot |= PROT_EXEC;
266 	rv = mmap(prefaddr, size, prot,
267 	    MAP_PRIVATE | MAP_ANON | MAP_ALIGNED(alignbit), -1, 0);
268 	if (rv == MAP_FAILED) {
269 		seterror(errno);
270 		return NULL;
271 	}
272 	return rv;
273 }
274 
275 void
276 rumpuser_unmap(void *addr, size_t len)
277 {
278 	int rv;
279 
280 	rv = munmap(addr, len);
281 	assert(rv == 0);
282 }
283 
284 void *
285 rumpuser_filemmap(int fd, off_t offset, size_t len, int flags, int *error)
286 {
287 	void *rv;
288 	int mmflags, prot;
289 
290 	if (flags & RUMPUSER_FILEMMAP_TRUNCATE) {
291 		if (ftruncate(fd, offset + len) == -1) {
292 			seterror(errno);
293 			return NULL;
294 		}
295 	}
296 
297 /* it's implicit */
298 #if defined(__sun__) && !defined(MAP_FILE)
299 #define MAP_FILE 0
300 #endif
301 
302 	mmflags = MAP_FILE;
303 	if (flags & RUMPUSER_FILEMMAP_SHARED)
304 		mmflags |= MAP_SHARED;
305 	else
306 		mmflags |= MAP_PRIVATE;
307 
308 	prot = 0;
309 	if (flags & RUMPUSER_FILEMMAP_READ)
310 		prot |= PROT_READ;
311 	if (flags & RUMPUSER_FILEMMAP_WRITE)
312 		prot |= PROT_WRITE;
313 
314 	rv = mmap(NULL, len, PROT_READ|PROT_WRITE, mmflags, fd, offset);
315 	if (rv == MAP_FAILED) {
316 		seterror(errno);
317 		return NULL;
318 	}
319 
320 	seterror(0);
321 	return rv;
322 }
323 
324 int
325 rumpuser_memsync(void *addr, size_t len, int *error)
326 {
327 
328 	DOCALL_KLOCK(int, (msync(addr, len, MS_SYNC)));
329 }
330 
331 int
332 rumpuser_open(const char *path, int ruflags, int *error)
333 {
334 	int flags;
335 
336 	switch (ruflags & RUMPUSER_OPEN_ACCMODE) {
337 	case RUMPUSER_OPEN_RDONLY:
338 		flags = O_RDONLY;
339 		break;
340 	case RUMPUSER_OPEN_WRONLY:
341 		flags = O_WRONLY;
342 		break;
343 	case RUMPUSER_OPEN_RDWR:
344 		flags = O_RDWR;
345 		break;
346 	default:
347 		*error = EINVAL;
348 		return -1;
349 	}
350 
351 #define TESTSET(_ru_, _h_) if (ruflags & _ru_) flags |= _h_;
352 	TESTSET(RUMPUSER_OPEN_CREATE, O_CREAT);
353 	TESTSET(RUMPUSER_OPEN_EXCL, O_EXCL);
354 #ifdef O_DIRECT
355 	TESTSET(RUMPUSER_OPEN_DIRECT, O_DIRECT);
356 #else
357 	if (ruflags & RUMPUSER_OPEN_DIRECT) {
358 		*error = EOPNOTSUPP;
359 		return -1;
360 	}
361 #endif
362 #undef TESTSET
363 
364 	DOCALL_KLOCK(int, (open(path, flags, 0644)));
365 }
366 
367 int
368 rumpuser_ioctl(int fd, u_long cmd, void *data, int *error)
369 {
370 
371 	DOCALL_KLOCK(int, (ioctl(fd, cmd, data)));
372 }
373 
374 int
375 rumpuser_close(int fd, int *error)
376 {
377 
378 	DOCALL(int, close(fd));
379 }
380 
381 int
382 rumpuser_fsync(int fd, int *error)
383 {
384 
385 	DOCALL_KLOCK(int, fsync(fd));
386 }
387 
388 ssize_t
389 rumpuser_read(int fd, void *data, size_t size, int *error)
390 {
391 	ssize_t rv;
392 
393 	KLOCK_WRAP(rv = read(fd, data, size));
394 	if (rv == -1)
395 		seterror(errno);
396 
397 	return rv;
398 }
399 
400 ssize_t
401 rumpuser_pread(int fd, void *data, size_t size, off_t offset, int *error)
402 {
403 	ssize_t rv;
404 
405 	KLOCK_WRAP(rv = pread(fd, data, size, offset));
406 	if (rv == -1)
407 		seterror(errno);
408 
409 	return rv;
410 }
411 
412 void
413 rumpuser_read_bio(int fd, void *data, size_t size, off_t offset,
414 	rump_biodone_fn biodone, void *biodonecookie)
415 {
416 	ssize_t rv;
417 	int error = 0;
418 
419 	rv = rumpuser_pread(fd, data, size, offset, &error);
420 	/* check against <0 instead of ==-1 to get typing below right */
421 	if (rv < 0)
422 		rv = 0;
423 
424 	/* LINTED: see above */
425 	biodone(biodonecookie, rv, error);
426 }
427 
428 ssize_t
429 rumpuser_write(int fd, const void *data, size_t size, int *error)
430 {
431 	ssize_t rv;
432 
433 	KLOCK_WRAP(rv = write(fd, data, size));
434 	if (rv == -1)
435 		seterror(errno);
436 
437 	return rv;
438 }
439 
440 ssize_t
441 rumpuser_pwrite(int fd, const void *data, size_t size, off_t offset, int *error)
442 {
443 	ssize_t rv;
444 
445 	KLOCK_WRAP(rv = pwrite(fd, data, size, offset));
446 	if (rv == -1)
447 		seterror(errno);
448 
449 	return rv;
450 }
451 
452 void
453 rumpuser_write_bio(int fd, const void *data, size_t size, off_t offset,
454 	rump_biodone_fn biodone, void *biodonecookie)
455 {
456 	ssize_t rv;
457 	int error = 0;
458 
459 	rv = rumpuser_pwrite(fd, data, size, offset, &error);
460 	/* check against <0 instead of ==-1 to get typing below right */
461 	if (rv < 0)
462 		rv = 0;
463 
464 	/* LINTED: see above */
465 	biodone(biodonecookie, rv, error);
466 }
467 
468 ssize_t
469 rumpuser_readv(int fd, const struct rumpuser_iovec *riov, int iovcnt,
470 	int *error)
471 {
472 	struct iovec *iovp;
473 	ssize_t rv;
474 	int i;
475 
476 	iovp = malloc(iovcnt * sizeof(struct iovec));
477 	if (iovp == NULL) {
478 		seterror(ENOMEM);
479 		return -1;
480 	}
481 	for (i = 0; i < iovcnt; i++) {
482 		iovp[i].iov_base = riov[i].iov_base;
483 		/*LINTED*/
484 		iovp[i].iov_len = riov[i].iov_len;
485 	}
486 
487 	KLOCK_WRAP(rv = readv(fd, iovp, iovcnt));
488 	if (rv == -1)
489 		seterror(errno);
490 	free(iovp);
491 
492 	return rv;
493 }
494 
495 ssize_t
496 rumpuser_writev(int fd, const struct rumpuser_iovec *riov, int iovcnt,
497 	int *error)
498 {
499 	struct iovec *iovp;
500 	ssize_t rv;
501 	int i;
502 
503 	iovp = malloc(iovcnt * sizeof(struct iovec));
504 	if (iovp == NULL) {
505 		seterror(ENOMEM);
506 		return -1;
507 	}
508 	for (i = 0; i < iovcnt; i++) {
509 		iovp[i].iov_base = riov[i].iov_base;
510 		/*LINTED*/
511 		iovp[i].iov_len = riov[i].iov_len;
512 	}
513 
514 	KLOCK_WRAP(rv = writev(fd, iovp, iovcnt));
515 	if (rv == -1)
516 		seterror(errno);
517 	free(iovp);
518 
519 	return rv;
520 }
521 
522 int
523 rumpuser_gettime(uint64_t *sec, uint64_t *nsec, int *error)
524 {
525 	struct timeval tv;
526 	int rv;
527 
528 	rv = gettimeofday(&tv, NULL);
529 	if (rv == -1) {
530 		seterror(errno);
531 		return rv;
532 	}
533 
534 	*sec = tv.tv_sec;
535 	*nsec = tv.tv_usec * 1000;
536 
537 	return 0;
538 }
539 
540 int
541 rumpuser_getenv(const char *name, char *buf, size_t blen, int *error)
542 {
543 
544 	DOCALL(int, getenv_r(name, buf, blen));
545 }
546 
547 int
548 rumpuser_gethostname(char *name, size_t namelen, int *error)
549 {
550 	char tmp[MAXHOSTNAMELEN];
551 
552 	if (gethostname(tmp, sizeof(tmp)) == -1) {
553 		snprintf(name, namelen, "rump-%05d.rumpdomain", (int)getpid());
554 	} else {
555 		snprintf(name, namelen, "rump-%05d.%s.rumpdomain",
556 		    (int)getpid(), tmp);
557 	}
558 
559 	*error = 0;
560 	return 0;
561 }
562 
563 int
564 rumpuser_poll(struct pollfd *fds, int nfds, int timeout, int *error)
565 {
566 
567 	DOCALL_KLOCK(int, (poll(fds, (nfds_t)nfds, timeout)));
568 }
569 
570 int
571 rumpuser_putchar(int c, int *error)
572 {
573 
574 	DOCALL(int, (putchar(c)));
575 }
576 
577 void
578 rumpuser_exit(int rv)
579 {
580 
581 	if (rv == RUMPUSER_PANIC)
582 		abort();
583 	else
584 		exit(rv);
585 }
586 
587 void
588 rumpuser_seterrno(int error)
589 {
590 
591 	errno = error;
592 }
593 
594 /*
595  * On NetBSD we use kqueue, on Linux we use inotify.  The underlying
596  * interface requirements aren't quite the same, but we have a very
597  * good chance of doing the fd->path mapping on Linux thanks to dcache,
598  * so just keep the existing interfaces for now.
599  */
600 #if defined(__NetBSD__)
601 int
602 rumpuser_writewatchfile_setup(int kq, int fd, intptr_t opaque, int *error)
603 {
604 	struct kevent kev;
605 
606 	if (kq == -1) {
607 		kq = kqueue();
608 		if (kq == -1) {
609 			seterror(errno);
610 			return -1;
611 		}
612 	}
613 
614 	EV_SET(&kev, fd, EVFILT_VNODE, EV_ADD|EV_ENABLE|EV_CLEAR,
615 	    NOTE_WRITE, 0, opaque);
616 	if (kevent(kq, &kev, 1, NULL, 0, NULL) == -1) {
617 		seterror(errno);
618 		return -1;
619 	}
620 
621 	return kq;
622 }
623 
624 int
625 rumpuser_writewatchfile_wait(int kq, intptr_t *opaque, int *error)
626 {
627 	struct kevent kev;
628 	int rv;
629 
630  again:
631 	KLOCK_WRAP(rv = kevent(kq, NULL, 0, &kev, 1, NULL));
632 	if (rv == -1) {
633 		if (errno == EINTR)
634 			goto again;
635 		seterror(errno);
636 		return -1;
637 	}
638 
639 	if (opaque)
640 		*opaque = kev.udata;
641 	return rv;
642 }
643 
644 #elif defined(__linux__)
645 #include <sys/inotify.h>
646 
647 int
648 rumpuser_writewatchfile_setup(int inotify, int fd, intptr_t notused, int *error)
649 {
650 	char procbuf[PATH_MAX], linkbuf[PATH_MAX];
651 	ssize_t nn;
652 
653 	if (inotify == -1) {
654 		inotify = inotify_init();
655 		if (inotify == -1) {
656 			seterror(errno);
657 			return -1;
658 		}
659 	}
660 
661 	/* ok, need to map fd into path for inotify */
662 	snprintf(procbuf, sizeof(procbuf), "/proc/self/fd/%d", fd);
663 	nn = readlink(procbuf, linkbuf, sizeof(linkbuf)-1);
664 	if (nn >= (ssize_t)sizeof(linkbuf)-1) {
665 		nn = -1;
666 		errno = E2BIG; /* pick something */
667 	}
668 	if (nn == -1) {
669 		seterror(errno);
670 		close(inotify);
671 		return -1;
672 	}
673 
674 	linkbuf[nn] = '\0';
675 	if (inotify_add_watch(inotify, linkbuf, IN_MODIFY) == -1) {
676 		seterror(errno);
677 		close(inotify);
678 		return -1;
679 	}
680 
681 	return inotify;
682 }
683 
684 int
685 rumpuser_writewatchfile_wait(int kq, intptr_t *opaque, int *error)
686 {
687 	struct inotify_event iev;
688 	ssize_t nn;
689 
690 	do {
691 		KLOCK_WRAP(nn = read(kq, &iev, sizeof(iev)));
692 	} while (errno == EINTR);
693 
694 	if (nn == -1) {
695 		seterror(errno);
696 		return -1;
697 	}
698 	return (nn/sizeof(iev));
699 }
700 
701 #else
702 
703 /* a polling default implementation */
704 int
705 rumpuser_writewatchfile_setup(int inotify, int fd, intptr_t notused, int *error)
706 {
707 	static int warned = 0;
708 
709 	if (!warned) {
710 		fprintf(stderr, "WARNING: rumpuser writewatchfile routines are "
711 		    "polling-only on this platform\n");
712 		warned = 1;
713 	}
714 
715 	return 0;
716 }
717 
718 int
719 rumpuser_writewatchfile_wait(int kq, intptr_t *opaque, int *error)
720 {
721 
722 	KLOCK_WRAP(usleep(10000));
723 	return 0;
724 }
725 #endif
726 
727 /*
728  * This is meant for safe debugging prints from the kernel.
729  */
730 int
731 rumpuser_dprintf(const char *format, ...)
732 {
733 	va_list ap;
734 	int rv;
735 
736 	va_start(ap, format);
737 	rv = vfprintf(stderr, format, ap);
738 	va_end(ap);
739 
740 	return rv;
741 }
742 
743 int
744 rumpuser_kill(int64_t pid, int sig, int *error)
745 {
746 
747 #ifdef __NetBSD__
748 	if (pid == RUMPUSER_PID_SELF) {
749 		DOCALL(int, raise(sig));
750 	} else {
751 		DOCALL(int, kill((pid_t)pid, sig));
752 	}
753 #else
754 	/* XXXfixme: signal numbers may not match on non-NetBSD */
755 	seterror(EOPNOTSUPP);
756 	return -1;
757 #endif
758 }
759 
760 int
761 rumpuser_getnhostcpu(void)
762 {
763 	int ncpu = 1;
764 
765 #if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__DragonFly__)
766 	size_t sz = sizeof(ncpu);
767 
768 	sysctlbyname("hw.ncpu", &ncpu, &sz, NULL, 0);
769 #elif defined(__linux__) || defined(__CYGWIN__)
770 	FILE *fp;
771 	char *line = NULL;
772 	size_t n = 0;
773 
774 	/* If anyone knows a better way, I'm all ears */
775 	if ((fp = fopen("/proc/cpuinfo", "r")) != NULL) {
776 		ncpu = 0;
777 		while (getline(&line, &n, fp) != -1) {
778 			if (strncmp(line,
779 			    "processor", sizeof("processor")-1) == 0)
780 			    	ncpu++;
781 		}
782 		if (ncpu == 0)
783 			ncpu = 1;
784 		free(line);
785 		fclose(fp);
786 	}
787 #elif __sun__
788 	/* XXX: this is just a rough estimate ... */
789 	ncpu = sysconf(_SC_NPROCESSORS_ONLN);
790 #endif
791 
792 	return ncpu;
793 }
794 
795 /* XXX: this hypercall needs a better name */
796 uint32_t
797 rumpuser_arc4random(void)
798 {
799 
800 	return arc4random();
801 }
802