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