1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * ffs-test.c -- user mode filesystem api for usb composite function
4  *
5  * Copyright (C) 2010 Samsung Electronics
6  *                    Author: Michal Nazarewicz <mina86@mina86.com>
7  */
8 
9 /* $(CROSS_COMPILE)cc -Wall -Wextra -g -o ffs-test ffs-test.c -lpthread */
10 
11 
12 #define _DEFAULT_SOURCE /* for endian.h */
13 
14 #include <endian.h>
15 #include <errno.h>
16 #include <fcntl.h>
17 #include <pthread.h>
18 #include <stdarg.h>
19 #include <stdbool.h>
20 #include <stdio.h>
21 #include <stdlib.h>
22 #include <string.h>
23 #include <sys/ioctl.h>
24 #include <sys/stat.h>
25 #include <sys/types.h>
26 #include <unistd.h>
27 #include <tools/le_byteshift.h>
28 
29 #include "../../include/uapi/linux/usb/functionfs.h"
30 
31 
32 /******************** Little Endian Handling ********************************/
33 
34 /*
35  * cpu_to_le16/32 are used when initializing structures, a context where a
36  * function call is not allowed. To solve this, we code cpu_to_le16/32 in a way
37  * that allows them to be used when initializing structures.
38  */
39 
40 #if __BYTE_ORDER == __LITTLE_ENDIAN
41 #define cpu_to_le16(x)  (x)
42 #define cpu_to_le32(x)  (x)
43 #else
44 #define cpu_to_le16(x)  ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8))
45 #define cpu_to_le32(x)  \
46 	((((x) & 0xff000000u) >> 24) | (((x) & 0x00ff0000u) >>  8) | \
47 	(((x) & 0x0000ff00u) <<  8) | (((x) & 0x000000ffu) << 24))
48 #endif
49 
50 #define le32_to_cpu(x)  le32toh(x)
51 #define le16_to_cpu(x)  le16toh(x)
52 
53 /******************** Messages and Errors ***********************************/
54 
55 static const char argv0[] = "ffs-test";
56 
57 static unsigned verbosity = 7;
58 
_msg(unsigned level,const char * fmt,...)59 static void _msg(unsigned level, const char *fmt, ...)
60 {
61 	if (level < 2)
62 		level = 2;
63 	else if (level > 7)
64 		level = 7;
65 
66 	if (level <= verbosity) {
67 		static const char levels[8][6] = {
68 			[2] = "crit:",
69 			[3] = "err: ",
70 			[4] = "warn:",
71 			[5] = "note:",
72 			[6] = "info:",
73 			[7] = "dbg: "
74 		};
75 
76 		int _errno = errno;
77 		va_list ap;
78 
79 		fprintf(stderr, "%s: %s ", argv0, levels[level]);
80 		va_start(ap, fmt);
81 		vfprintf(stderr, fmt, ap);
82 		va_end(ap);
83 
84 		if (fmt[strlen(fmt) - 1] != '\n') {
85 			char buffer[128];
86 			strerror_r(_errno, buffer, sizeof buffer);
87 			fprintf(stderr, ": (-%d) %s\n", _errno, buffer);
88 		}
89 
90 		fflush(stderr);
91 	}
92 }
93 
94 #define die(...)  (_msg(2, __VA_ARGS__), exit(1))
95 #define err(...)   _msg(3, __VA_ARGS__)
96 #define warn(...)  _msg(4, __VA_ARGS__)
97 #define note(...)  _msg(5, __VA_ARGS__)
98 #define info(...)  _msg(6, __VA_ARGS__)
99 #define debug(...) _msg(7, __VA_ARGS__)
100 
101 #define die_on(cond, ...) do { \
102 	if (cond) \
103 		die(__VA_ARGS__); \
104 	} while (0)
105 
106 
107 /******************** Descriptors and Strings *******************************/
108 
109 static const struct {
110 	struct usb_functionfs_descs_head_v2 header;
111 	__le32 fs_count;
112 	__le32 hs_count;
113 	__le32 ss_count;
114 	struct {
115 		struct usb_interface_descriptor intf;
116 		struct usb_endpoint_descriptor_no_audio sink;
117 		struct usb_endpoint_descriptor_no_audio source;
118 	} __attribute__((packed)) fs_descs, hs_descs;
119 	struct {
120 		struct usb_interface_descriptor intf;
121 		struct usb_endpoint_descriptor_no_audio sink;
122 		struct usb_ss_ep_comp_descriptor sink_comp;
123 		struct usb_endpoint_descriptor_no_audio source;
124 		struct usb_ss_ep_comp_descriptor source_comp;
125 	} ss_descs;
126 } __attribute__((packed)) descriptors = {
127 	.header = {
128 		.magic = cpu_to_le32(FUNCTIONFS_DESCRIPTORS_MAGIC_V2),
129 		.flags = cpu_to_le32(FUNCTIONFS_HAS_FS_DESC |
130 				     FUNCTIONFS_HAS_HS_DESC |
131 				     FUNCTIONFS_HAS_SS_DESC),
132 		.length = cpu_to_le32(sizeof descriptors),
133 	},
134 	.fs_count = cpu_to_le32(3),
135 	.fs_descs = {
136 		.intf = {
137 			.bLength = sizeof descriptors.fs_descs.intf,
138 			.bDescriptorType = USB_DT_INTERFACE,
139 			.bNumEndpoints = 2,
140 			.bInterfaceClass = USB_CLASS_VENDOR_SPEC,
141 			.iInterface = 1,
142 		},
143 		.sink = {
144 			.bLength = sizeof descriptors.fs_descs.sink,
145 			.bDescriptorType = USB_DT_ENDPOINT,
146 			.bEndpointAddress = 1 | USB_DIR_IN,
147 			.bmAttributes = USB_ENDPOINT_XFER_BULK,
148 			/* .wMaxPacketSize = autoconfiguration (kernel) */
149 		},
150 		.source = {
151 			.bLength = sizeof descriptors.fs_descs.source,
152 			.bDescriptorType = USB_DT_ENDPOINT,
153 			.bEndpointAddress = 2 | USB_DIR_OUT,
154 			.bmAttributes = USB_ENDPOINT_XFER_BULK,
155 			/* .wMaxPacketSize = autoconfiguration (kernel) */
156 		},
157 	},
158 	.hs_count = cpu_to_le32(3),
159 	.hs_descs = {
160 		.intf = {
161 			.bLength = sizeof descriptors.fs_descs.intf,
162 			.bDescriptorType = USB_DT_INTERFACE,
163 			.bNumEndpoints = 2,
164 			.bInterfaceClass = USB_CLASS_VENDOR_SPEC,
165 			.iInterface = 1,
166 		},
167 		.sink = {
168 			.bLength = sizeof descriptors.hs_descs.sink,
169 			.bDescriptorType = USB_DT_ENDPOINT,
170 			.bEndpointAddress = 1 | USB_DIR_IN,
171 			.bmAttributes = USB_ENDPOINT_XFER_BULK,
172 			.wMaxPacketSize = cpu_to_le16(512),
173 		},
174 		.source = {
175 			.bLength = sizeof descriptors.hs_descs.source,
176 			.bDescriptorType = USB_DT_ENDPOINT,
177 			.bEndpointAddress = 2 | USB_DIR_OUT,
178 			.bmAttributes = USB_ENDPOINT_XFER_BULK,
179 			.wMaxPacketSize = cpu_to_le16(512),
180 			.bInterval = 1, /* NAK every 1 uframe */
181 		},
182 	},
183 	.ss_count = cpu_to_le32(5),
184 	.ss_descs = {
185 		.intf = {
186 			.bLength = sizeof descriptors.fs_descs.intf,
187 			.bDescriptorType = USB_DT_INTERFACE,
188 			.bNumEndpoints = 2,
189 			.bInterfaceClass = USB_CLASS_VENDOR_SPEC,
190 			.iInterface = 1,
191 		},
192 		.sink = {
193 			.bLength = sizeof descriptors.hs_descs.sink,
194 			.bDescriptorType = USB_DT_ENDPOINT,
195 			.bEndpointAddress = 1 | USB_DIR_IN,
196 			.bmAttributes = USB_ENDPOINT_XFER_BULK,
197 			.wMaxPacketSize = cpu_to_le16(1024),
198 		},
199 		.sink_comp = {
200 			.bLength = USB_DT_SS_EP_COMP_SIZE,
201 			.bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
202 			.bMaxBurst = 0,
203 			.bmAttributes = 0,
204 			.wBytesPerInterval = 0,
205 		},
206 		.source = {
207 			.bLength = sizeof descriptors.hs_descs.source,
208 			.bDescriptorType = USB_DT_ENDPOINT,
209 			.bEndpointAddress = 2 | USB_DIR_OUT,
210 			.bmAttributes = USB_ENDPOINT_XFER_BULK,
211 			.wMaxPacketSize = cpu_to_le16(1024),
212 			.bInterval = 1, /* NAK every 1 uframe */
213 		},
214 		.source_comp = {
215 			.bLength = USB_DT_SS_EP_COMP_SIZE,
216 			.bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
217 			.bMaxBurst = 0,
218 			.bmAttributes = 0,
219 			.wBytesPerInterval = 0,
220 		},
221 	},
222 };
223 
descs_to_legacy(void ** legacy,const void * descriptors_v2)224 static size_t descs_to_legacy(void **legacy, const void *descriptors_v2)
225 {
226 	const unsigned char *descs_end, *descs_start;
227 	__u32 length, fs_count = 0, hs_count = 0, count;
228 
229 	/* Read v2 header */
230 	{
231 		const struct {
232 			const struct usb_functionfs_descs_head_v2 header;
233 			const __le32 counts[];
234 		} __attribute__((packed)) *const in = descriptors_v2;
235 		const __le32 *counts = in->counts;
236 		__u32 flags;
237 
238 		if (le32_to_cpu(in->header.magic) !=
239 		    FUNCTIONFS_DESCRIPTORS_MAGIC_V2)
240 			return 0;
241 		length = le32_to_cpu(in->header.length);
242 		if (length <= sizeof in->header)
243 			return 0;
244 		length -= sizeof in->header;
245 		flags = le32_to_cpu(in->header.flags);
246 		if (flags & ~(FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC |
247 			      FUNCTIONFS_HAS_SS_DESC))
248 			return 0;
249 
250 #define GET_NEXT_COUNT_IF_FLAG(ret, flg) do {		\
251 			if (!(flags & (flg)))		\
252 				break;			\
253 			if (length < 4)			\
254 				return 0;		\
255 			ret = le32_to_cpu(*counts);	\
256 			length -= 4;			\
257 			++counts;			\
258 		} while (0)
259 
260 		GET_NEXT_COUNT_IF_FLAG(fs_count, FUNCTIONFS_HAS_FS_DESC);
261 		GET_NEXT_COUNT_IF_FLAG(hs_count, FUNCTIONFS_HAS_HS_DESC);
262 		GET_NEXT_COUNT_IF_FLAG(count, FUNCTIONFS_HAS_SS_DESC);
263 
264 		count = fs_count + hs_count;
265 		if (!count)
266 			return 0;
267 		descs_start = (const void *)counts;
268 
269 #undef GET_NEXT_COUNT_IF_FLAG
270 	}
271 
272 	/*
273 	 * Find the end of FS and HS USB descriptors.  SS descriptors
274 	 * are ignored since legacy format does not support them.
275 	 */
276 	descs_end = descs_start;
277 	do {
278 		if (length < *descs_end)
279 			return 0;
280 		length -= *descs_end;
281 		descs_end += *descs_end;
282 	} while (--count);
283 
284 	/* Allocate legacy descriptors and copy the data. */
285 	{
286 #pragma GCC diagnostic push
287 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
288 		struct {
289 			struct usb_functionfs_descs_head header;
290 			__u8 descriptors[];
291 		} __attribute__((packed)) *out;
292 #pragma GCC diagnostic pop
293 
294 		length = sizeof out->header + (descs_end - descs_start);
295 		out = malloc(length);
296 		out->header.magic = cpu_to_le32(FUNCTIONFS_DESCRIPTORS_MAGIC);
297 		out->header.length = cpu_to_le32(length);
298 		out->header.fs_count = cpu_to_le32(fs_count);
299 		out->header.hs_count = cpu_to_le32(hs_count);
300 		memcpy(out->descriptors, descs_start, descs_end - descs_start);
301 		*legacy = out;
302 	}
303 
304 	return length;
305 }
306 
307 
308 #define STR_INTERFACE_ "Source/Sink"
309 
310 static const struct {
311 	struct usb_functionfs_strings_head header;
312 	struct {
313 		__le16 code;
314 		const char str1[sizeof STR_INTERFACE_];
315 	} __attribute__((packed)) lang0;
316 } __attribute__((packed)) strings = {
317 	.header = {
318 		.magic = cpu_to_le32(FUNCTIONFS_STRINGS_MAGIC),
319 		.length = cpu_to_le32(sizeof strings),
320 		.str_count = cpu_to_le32(1),
321 		.lang_count = cpu_to_le32(1),
322 	},
323 	.lang0 = {
324 		cpu_to_le16(0x0409), /* en-us */
325 		STR_INTERFACE_,
326 	},
327 };
328 
329 #define STR_INTERFACE strings.lang0.str1
330 
331 
332 /******************** Files and Threads Handling ****************************/
333 
334 struct thread;
335 
336 static ssize_t read_wrap(struct thread *t, void *buf, size_t nbytes);
337 static ssize_t write_wrap(struct thread *t, const void *buf, size_t nbytes);
338 static ssize_t ep0_consume(struct thread *t, const void *buf, size_t nbytes);
339 static ssize_t fill_in_buf(struct thread *t, void *buf, size_t nbytes);
340 static ssize_t empty_out_buf(struct thread *t, const void *buf, size_t nbytes);
341 
342 
343 static struct thread {
344 	const char *const filename;
345 	size_t buf_size;
346 
347 	ssize_t (*in)(struct thread *, void *, size_t);
348 	const char *const in_name;
349 
350 	ssize_t (*out)(struct thread *, const void *, size_t);
351 	const char *const out_name;
352 
353 	int fd;
354 	pthread_t id;
355 	void *buf;
356 	ssize_t status;
357 } threads[] = {
358 	{
359 		"ep0", 4 * sizeof(struct usb_functionfs_event),
360 		read_wrap, NULL,
361 		ep0_consume, "<consume>",
362 		0, 0, NULL, 0
363 	},
364 	{
365 		"ep1", 8 * 1024,
366 		fill_in_buf, "<in>",
367 		write_wrap, NULL,
368 		0, 0, NULL, 0
369 	},
370 	{
371 		"ep2", 8 * 1024,
372 		read_wrap, NULL,
373 		empty_out_buf, "<out>",
374 		0, 0, NULL, 0
375 	},
376 };
377 
378 
init_thread(struct thread * t)379 static void init_thread(struct thread *t)
380 {
381 	t->buf = malloc(t->buf_size);
382 	die_on(!t->buf, "malloc");
383 
384 	t->fd = open(t->filename, O_RDWR);
385 	die_on(t->fd < 0, "%s", t->filename);
386 }
387 
cleanup_thread(void * arg)388 static void cleanup_thread(void *arg)
389 {
390 	struct thread *t = arg;
391 	int ret, fd;
392 
393 	fd = t->fd;
394 	if (t->fd < 0)
395 		return;
396 	t->fd = -1;
397 
398 	/* test the FIFO ioctls (non-ep0 code paths) */
399 	if (t != threads) {
400 		ret = ioctl(fd, FUNCTIONFS_FIFO_STATUS);
401 		if (ret < 0) {
402 			/* ENODEV reported after disconnect */
403 			if (errno != ENODEV)
404 				err("%s: get fifo status", t->filename);
405 		} else if (ret) {
406 			warn("%s: unclaimed = %d\n", t->filename, ret);
407 			if (ioctl(fd, FUNCTIONFS_FIFO_FLUSH) < 0)
408 				err("%s: fifo flush", t->filename);
409 		}
410 	}
411 
412 	if (close(fd) < 0)
413 		err("%s: close", t->filename);
414 
415 	free(t->buf);
416 	t->buf = NULL;
417 }
418 
start_thread_helper(void * arg)419 static void *start_thread_helper(void *arg)
420 {
421 	const char *name, *op, *in_name, *out_name;
422 	struct thread *t = arg;
423 	ssize_t ret;
424 
425 	info("%s: starts\n", t->filename);
426 	in_name = t->in_name ? t->in_name : t->filename;
427 	out_name = t->out_name ? t->out_name : t->filename;
428 
429 	pthread_cleanup_push(cleanup_thread, arg);
430 
431 	for (;;) {
432 		pthread_testcancel();
433 
434 		ret = t->in(t, t->buf, t->buf_size);
435 		if (ret > 0) {
436 			ret = t->out(t, t->buf, ret);
437 			name = out_name;
438 			op = "write";
439 		} else {
440 			name = in_name;
441 			op = "read";
442 		}
443 
444 		if (ret > 0) {
445 			/* nop */
446 		} else if (!ret) {
447 			debug("%s: %s: EOF", name, op);
448 			break;
449 		} else if (errno == EINTR || errno == EAGAIN) {
450 			debug("%s: %s", name, op);
451 		} else {
452 			warn("%s: %s", name, op);
453 			break;
454 		}
455 	}
456 
457 	pthread_cleanup_pop(1);
458 
459 	t->status = ret;
460 	info("%s: ends\n", t->filename);
461 	return NULL;
462 }
463 
start_thread(struct thread * t)464 static void start_thread(struct thread *t)
465 {
466 	debug("%s: starting\n", t->filename);
467 
468 	die_on(pthread_create(&t->id, NULL, start_thread_helper, t) < 0,
469 	       "pthread_create(%s)", t->filename);
470 }
471 
join_thread(struct thread * t)472 static void join_thread(struct thread *t)
473 {
474 	int ret = pthread_join(t->id, NULL);
475 
476 	if (ret < 0)
477 		err("%s: joining thread", t->filename);
478 	else
479 		debug("%s: joined\n", t->filename);
480 }
481 
482 
read_wrap(struct thread * t,void * buf,size_t nbytes)483 static ssize_t read_wrap(struct thread *t, void *buf, size_t nbytes)
484 {
485 	return read(t->fd, buf, nbytes);
486 }
487 
write_wrap(struct thread * t,const void * buf,size_t nbytes)488 static ssize_t write_wrap(struct thread *t, const void *buf, size_t nbytes)
489 {
490 	return write(t->fd, buf, nbytes);
491 }
492 
493 
494 /******************** Empty/Fill buffer routines ****************************/
495 
496 /* 0 -- stream of zeros, 1 -- i % 63, 2 -- pipe */
497 enum pattern { PAT_ZERO, PAT_SEQ, PAT_PIPE };
498 static enum pattern pattern;
499 
500 static ssize_t
fill_in_buf(struct thread * ignore,void * buf,size_t nbytes)501 fill_in_buf(struct thread *ignore, void *buf, size_t nbytes)
502 {
503 	size_t i;
504 	__u8 *p;
505 
506 	(void)ignore;
507 
508 	switch (pattern) {
509 	case PAT_ZERO:
510 		memset(buf, 0, nbytes);
511 		break;
512 
513 	case PAT_SEQ:
514 		for (p = buf, i = 0; i < nbytes; ++i, ++p)
515 			*p = i % 63;
516 		break;
517 
518 	case PAT_PIPE:
519 		return fread(buf, 1, nbytes, stdin);
520 	}
521 
522 	return nbytes;
523 }
524 
525 static ssize_t
empty_out_buf(struct thread * ignore,const void * buf,size_t nbytes)526 empty_out_buf(struct thread *ignore, const void *buf, size_t nbytes)
527 {
528 	const __u8 *p;
529 	__u8 expected;
530 	ssize_t ret;
531 	size_t len;
532 
533 	(void)ignore;
534 
535 	switch (pattern) {
536 	case PAT_ZERO:
537 		expected = 0;
538 		for (p = buf, len = 0; len < nbytes; ++p, ++len)
539 			if (*p)
540 				goto invalid;
541 		break;
542 
543 	case PAT_SEQ:
544 		for (p = buf, len = 0; len < nbytes; ++p, ++len)
545 			if (*p != len % 63) {
546 				expected = len % 63;
547 				goto invalid;
548 			}
549 		break;
550 
551 	case PAT_PIPE:
552 		ret = fwrite(buf, nbytes, 1, stdout);
553 		if (ret > 0)
554 			fflush(stdout);
555 		break;
556 
557 invalid:
558 		err("bad OUT byte %zd, expected %02x got %02x\n",
559 		    len, expected, *p);
560 		for (p = buf, len = 0; len < nbytes; ++p, ++len) {
561 			if (0 == (len % 32))
562 				fprintf(stderr, "%4zd:", len);
563 			fprintf(stderr, " %02x", *p);
564 			if (31 == (len % 32))
565 				fprintf(stderr, "\n");
566 		}
567 		fflush(stderr);
568 		errno = EILSEQ;
569 		return -1;
570 	}
571 
572 	return len;
573 }
574 
575 
576 /******************** Endpoints routines ************************************/
577 
handle_setup(const struct usb_ctrlrequest * setup)578 static void handle_setup(const struct usb_ctrlrequest *setup)
579 {
580 	printf("bRequestType = %d\n", setup->bRequestType);
581 	printf("bRequest     = %d\n", setup->bRequest);
582 	printf("wValue       = %d\n", le16_to_cpu(setup->wValue));
583 	printf("wIndex       = %d\n", le16_to_cpu(setup->wIndex));
584 	printf("wLength      = %d\n", le16_to_cpu(setup->wLength));
585 }
586 
587 static ssize_t
ep0_consume(struct thread * ignore,const void * buf,size_t nbytes)588 ep0_consume(struct thread *ignore, const void *buf, size_t nbytes)
589 {
590 	static const char *const names[] = {
591 		[FUNCTIONFS_BIND] = "BIND",
592 		[FUNCTIONFS_UNBIND] = "UNBIND",
593 		[FUNCTIONFS_ENABLE] = "ENABLE",
594 		[FUNCTIONFS_DISABLE] = "DISABLE",
595 		[FUNCTIONFS_SETUP] = "SETUP",
596 		[FUNCTIONFS_SUSPEND] = "SUSPEND",
597 		[FUNCTIONFS_RESUME] = "RESUME",
598 	};
599 
600 	const struct usb_functionfs_event *event = buf;
601 	size_t n;
602 
603 	(void)ignore;
604 
605 	for (n = nbytes / sizeof *event; n; --n, ++event)
606 		switch (event->type) {
607 		case FUNCTIONFS_BIND:
608 		case FUNCTIONFS_UNBIND:
609 		case FUNCTIONFS_ENABLE:
610 		case FUNCTIONFS_DISABLE:
611 		case FUNCTIONFS_SETUP:
612 		case FUNCTIONFS_SUSPEND:
613 		case FUNCTIONFS_RESUME:
614 			printf("Event %s\n", names[event->type]);
615 			if (event->type == FUNCTIONFS_SETUP)
616 				handle_setup(&event->u.setup);
617 			break;
618 
619 		default:
620 			printf("Event %03u (unknown)\n", event->type);
621 		}
622 
623 	return nbytes;
624 }
625 
ep0_init(struct thread * t,bool legacy_descriptors)626 static void ep0_init(struct thread *t, bool legacy_descriptors)
627 {
628 	void *legacy;
629 	ssize_t ret;
630 	size_t len;
631 
632 	if (legacy_descriptors) {
633 		info("%s: writing descriptors\n", t->filename);
634 		goto legacy;
635 	}
636 
637 	info("%s: writing descriptors (in v2 format)\n", t->filename);
638 	ret = write(t->fd, &descriptors, sizeof descriptors);
639 
640 	if (ret < 0 && errno == EINVAL) {
641 		warn("%s: new format rejected, trying legacy\n", t->filename);
642 legacy:
643 		len = descs_to_legacy(&legacy, &descriptors);
644 		if (len) {
645 			ret = write(t->fd, legacy, len);
646 			free(legacy);
647 		}
648 	}
649 	die_on(ret < 0, "%s: write: descriptors", t->filename);
650 
651 	info("%s: writing strings\n", t->filename);
652 	ret = write(t->fd, &strings, sizeof strings);
653 	die_on(ret < 0, "%s: write: strings", t->filename);
654 }
655 
656 
657 /******************** Main **************************************************/
658 
main(int argc,char ** argv)659 int main(int argc, char **argv)
660 {
661 	bool legacy_descriptors;
662 	unsigned i;
663 
664 	legacy_descriptors = argc > 2 && !strcmp(argv[1], "-l");
665 
666 	init_thread(threads);
667 	ep0_init(threads, legacy_descriptors);
668 
669 	for (i = 1; i < sizeof threads / sizeof *threads; ++i)
670 		init_thread(threads + i);
671 
672 	for (i = 1; i < sizeof threads / sizeof *threads; ++i)
673 		start_thread(threads + i);
674 
675 	start_thread_helper(threads);
676 
677 	for (i = 1; i < sizeof threads / sizeof *threads; ++i)
678 		join_thread(threads + i);
679 
680 	return 0;
681 }
682