Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
/*	$NetBSD: bl.c,v 1.28 2016/07/29 17:13:09 christos Exp $	*/

/*-
 * Copyright (c) 2014 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Christos Zoulas.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <sys/cdefs.h>
__RCSID("$NetBSD: bl.c,v 1.28 2016/07/29 17:13:09 christos Exp $");

#include <sys/param.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/un.h>

#include <stdio.h>
#include <string.h>
#include <syslog.h>
#include <signal.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdint.h>
#include <stdbool.h>
#include <errno.h>
#include <stdarg.h>
#include <netinet/in.h>
#ifdef _REENTRANT
#include <pthread.h>
#endif

#include "bl.h"

typedef struct {
	uint32_t bl_len;
	uint32_t bl_version;
	uint32_t bl_type;
	uint32_t bl_salen;
	struct sockaddr_storage bl_ss;
	char bl_data[];
} bl_message_t;

struct blacklist {
#ifdef _REENTRANT
	pthread_mutex_t b_mutex;
# define BL_INIT(b)	pthread_mutex_init(&b->b_mutex, NULL)
# define BL_LOCK(b)	pthread_mutex_lock(&b->b_mutex)
# define BL_UNLOCK(b)	pthread_mutex_unlock(&b->b_mutex)
#else
# define BL_INIT(b)	do {} while(/*CONSTCOND*/0)
# define BL_LOCK(b)	BL_INIT(b)
# define BL_UNLOCK(b)	BL_INIT(b)
#endif
	int b_fd;
	int b_connected;
	struct sockaddr_un b_sun;
	void (*b_fun)(int, const char *, va_list);
	bl_info_t b_info;
};

#define BL_VERSION	1

bool
bl_isconnected(bl_t b)
{
	return b->b_connected == 0;
}

int
bl_getfd(bl_t b)
{
	return b->b_fd;
}

static void
bl_reset(bl_t b, bool locked)
{
	int serrno = errno;
	if (!locked)
		BL_LOCK(b);
	close(b->b_fd);
	errno = serrno;
	b->b_fd = -1;
	b->b_connected = -1;
	if (!locked)
		BL_UNLOCK(b);
}

static void
bl_log(void (*fun)(int, const char *, va_list), int level,
    const char *fmt, ...)
{
	va_list ap;
	int serrno = errno;

	va_start(ap, fmt);
	(*fun)(level, fmt, ap);
	va_end(ap);
	errno = serrno;
}

static int
bl_init(bl_t b, bool srv)
{
	static int one = 1;
	/* AF_UNIX address of local logger */
	mode_t om;
	int rv, serrno;
	struct sockaddr_un *sun = &b->b_sun;

#ifndef SOCK_NONBLOCK
#define SOCK_NONBLOCK 0
#endif
#ifndef SOCK_CLOEXEC
#define SOCK_CLOEXEC 0
#endif
#ifndef SOCK_NOSIGPIPE
#define SOCK_NOSIGPIPE 0
#endif

	BL_LOCK(b);

	if (b->b_fd == -1) {
		b->b_fd = socket(PF_LOCAL,
		    SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK|SOCK_NOSIGPIPE, 0);
		if (b->b_fd == -1) {
			bl_log(b->b_fun, LOG_ERR, "%s: socket failed (%s)",
			    __func__, strerror(errno));
			BL_UNLOCK(b);
			return -1;
		}
#if SOCK_CLOEXEC == 0
		fcntl(b->b_fd, F_SETFD, FD_CLOEXEC);
#endif
#if SOCK_NONBLOCK == 0
		fcntl(b->b_fd, F_SETFL, fcntl(b->b_fd, F_GETFL) | O_NONBLOCK);
#endif
#if SOCK_NOSIGPIPE == 0
#ifdef SO_NOSIGPIPE
		int o = 1;
		setsockopt(b->b_fd, SOL_SOCKET, SO_NOSIGPIPE, &o, sizeof(o));
#else
		signal(SIGPIPE, SIG_IGN);
#endif
#endif
	}

	if (bl_isconnected(b)) {
		BL_UNLOCK(b);
		return 0;
	}

	/*
	 * We try to connect anyway even when we are a server to verify
	 * that no other server is listening to the socket. If we succeed
	 * to connect and we are a server, someone else owns it.
	 */
	rv = connect(b->b_fd, (const void *)sun, (socklen_t)sizeof(*sun));
	if (rv == 0) {
		if (srv) {
			bl_log(b->b_fun, LOG_ERR,
			    "%s: another daemon is handling `%s'",
			    __func__, sun->sun_path);
			goto out;
		}
	} else {
		if (!srv) {
			/*
			 * If the daemon is not running, we just try a
			 * connect, so leave the socket alone until it does
			 * and only log once.
			 */
			if (b->b_connected != 1) {
				bl_log(b->b_fun, LOG_DEBUG,
				    "%s: connect failed for `%s' (%s)",
				    __func__, sun->sun_path, strerror(errno));
				b->b_connected = 1;
			}
			BL_UNLOCK(b);
			return -1;
		}
		bl_log(b->b_fun, LOG_DEBUG, "Connected to blacklist server",
		    __func__);
	}

	if (srv) {
		(void)unlink(sun->sun_path);
		om = umask(0);
		rv = bind(b->b_fd, (const void *)sun, (socklen_t)sizeof(*sun));
		serrno = errno;
		(void)umask(om);
		errno = serrno;
		if (rv == -1) {
			bl_log(b->b_fun, LOG_ERR,
			    "%s: bind failed for `%s' (%s)",
			    __func__, sun->sun_path, strerror(errno));
			goto out;
		}
	}

	b->b_connected = 0;
#define GOT_FD		1
#if defined(LOCAL_CREDS)
#define CRED_LEVEL	0
#define	CRED_NAME	LOCAL_CREDS
#define CRED_SC_UID	sc_euid
#define CRED_SC_GID	sc_egid
#define CRED_MESSAGE	SCM_CREDS
#define CRED_SIZE	SOCKCREDSIZE(NGROUPS_MAX)
#define CRED_TYPE	struct sockcred
#define GOT_CRED	2
#elif defined(SO_PASSCRED)
#define CRED_LEVEL	SOL_SOCKET
#define	CRED_NAME	SO_PASSCRED
#define CRED_SC_UID	uid
#define CRED_SC_GID	gid
#define CRED_MESSAGE	SCM_CREDENTIALS
#define CRED_SIZE	sizeof(struct ucred)
#define CRED_TYPE	struct ucred
#define GOT_CRED	2
#else
#define GOT_CRED	0
/*
 * getpeereid() and LOCAL_PEERCRED don't help here
 * because we are not a stream socket!
 */
#define	CRED_SIZE	0
#define CRED_TYPE	void * __unused
#endif

#ifdef CRED_LEVEL
	if (setsockopt(b->b_fd, CRED_LEVEL, CRED_NAME,
	    &one, (socklen_t)sizeof(one)) == -1) {
		bl_log(b->b_fun, LOG_ERR, "%s: setsockopt %s "
		    "failed (%s)", __func__, __STRING(CRED_NAME),
		    strerror(errno));
		goto out;
	}
#endif

	BL_UNLOCK(b);
	return 0;
out:
	bl_reset(b, true);
	BL_UNLOCK(b);
	return -1;
}

bl_t
bl_create(bool srv, const char *path, void (*fun)(int, const char *, va_list))
{
	bl_t b = calloc(1, sizeof(*b));
	if (b == NULL)
		goto out;
	b->b_fun = fun == NULL ? vsyslog : fun;
	b->b_fd = -1;
	b->b_connected = -1;
	BL_INIT(b);

	memset(&b->b_sun, 0, sizeof(b->b_sun));
	b->b_sun.sun_family = AF_LOCAL;
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
	b->b_sun.sun_len = sizeof(b->b_sun);
#endif
	strlcpy(b->b_sun.sun_path,
	    path ? path : _PATH_BLSOCK, sizeof(b->b_sun.sun_path));

	bl_init(b, srv);
	return b;
out:
	free(b);
	bl_log(fun, LOG_ERR, "%s: malloc failed (%s)", __func__,
	    strerror(errno));
	return NULL;
}

void
bl_destroy(bl_t b)
{
	bl_reset(b, false);
	free(b);
}

static int
bl_getsock(bl_t b, struct sockaddr_storage *ss, const struct sockaddr *sa,
    socklen_t slen, const char *ctx)
{
	uint8_t family;

	memset(ss, 0, sizeof(*ss));

	switch (slen) {
	case 0:
		return 0;
	case sizeof(struct sockaddr_in):
		family = AF_INET;
		break;
	case sizeof(struct sockaddr_in6):
		family = AF_INET6;
		break;
	default:
		bl_log(b->b_fun, LOG_ERR, "%s: invalid socket len %u (%s)",
		    __func__, (unsigned)slen, ctx);
		errno = EINVAL;
		return -1;
	}

	memcpy(ss, sa, slen);

	if (ss->ss_family != family) {
		bl_log(b->b_fun, LOG_INFO,
		    "%s: correcting socket family %d to %d (%s)",
		    __func__, ss->ss_family, family, ctx);
		ss->ss_family = family;
	}

#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
	if (ss->ss_len != slen) {
		bl_log(b->b_fun, LOG_INFO,
		    "%s: correcting socket len %u to %u (%s)",
		    __func__, ss->ss_len, (unsigned)slen, ctx);
		ss->ss_len = (uint8_t)slen;
	}
#endif
	return 0;
}

int
bl_send(bl_t b, bl_type_t e, int pfd, const struct sockaddr *sa,
    socklen_t slen, const char *ctx)
{
	struct msghdr   msg;
	struct iovec    iov;
	union {
		char ctrl[CMSG_SPACE(sizeof(int))];
		uint32_t fd;
	} ua;
	struct cmsghdr *cmsg;
	union {
		bl_message_t bl;
		char buf[512];
	} ub;
	size_t ctxlen, tried;
#define NTRIES	5

	ctxlen = strlen(ctx);
	if (ctxlen > 128)
		ctxlen = 128;

	iov.iov_base = ub.buf;
	iov.iov_len = sizeof(bl_message_t) + ctxlen;
	ub.bl.bl_len = (uint32_t)iov.iov_len;
	ub.bl.bl_version = BL_VERSION;
	ub.bl.bl_type = (uint32_t)e;

	if (bl_getsock(b, &ub.bl.bl_ss, sa, slen, ctx) == -1)
		return -1;


	ub.bl.bl_salen = slen;
	memcpy(ub.bl.bl_data, ctx, ctxlen);

	msg.msg_name = NULL;
	msg.msg_namelen = 0;
	msg.msg_iov = &iov;
	msg.msg_iovlen = 1;
	msg.msg_flags = 0;

	msg.msg_control = ua.ctrl;
	msg.msg_controllen = sizeof(ua.ctrl);

	cmsg = CMSG_FIRSTHDR(&msg);
	cmsg->cmsg_len = CMSG_LEN(sizeof(int));
	cmsg->cmsg_level = SOL_SOCKET;
	cmsg->cmsg_type = SCM_RIGHTS;

	memcpy(CMSG_DATA(cmsg), &pfd, sizeof(pfd));

	tried = 0;
again:
	if (bl_init(b, false) == -1)
		return -1;

	if ((sendmsg(b->b_fd, &msg, 0) == -1) && tried++ < NTRIES) {
		bl_reset(b, false);
		goto again;
	}
	return tried >= NTRIES ? -1 : 0;
}

bl_info_t *
bl_recv(bl_t b)
{
        struct msghdr   msg;
        struct iovec    iov;
	union {
		char ctrl[CMSG_SPACE(sizeof(int)) + CMSG_SPACE(CRED_SIZE)];
		uint32_t fd;
		CRED_TYPE sc;
	} ua;
	struct cmsghdr *cmsg;
	CRED_TYPE *sc;
	union {
		bl_message_t bl;
		char buf[512];
	} ub;
	int got;
	ssize_t rlen;
	bl_info_t *bi = &b->b_info;

	got = 0;
	memset(bi, 0, sizeof(*bi));

	iov.iov_base = ub.buf;
	iov.iov_len = sizeof(ub);

	msg.msg_name = NULL;
	msg.msg_namelen = 0;
	msg.msg_iov = &iov;
	msg.msg_iovlen = 1;
	msg.msg_flags = 0;

	msg.msg_control = ua.ctrl;
	msg.msg_controllen = sizeof(ua.ctrl) + 100;

        rlen = recvmsg(b->b_fd, &msg, 0);
        if (rlen == -1) {
		bl_log(b->b_fun, LOG_ERR, "%s: recvmsg failed (%s)", __func__,
		    strerror(errno));
		return NULL;
        }

	for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
		if (cmsg->cmsg_level != SOL_SOCKET) {
			bl_log(b->b_fun, LOG_ERR,
			    "%s: unexpected cmsg_level %d",
			    __func__, cmsg->cmsg_level);
			continue;
		}
		switch (cmsg->cmsg_type) {
		case SCM_RIGHTS:
			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
				bl_log(b->b_fun, LOG_ERR,
				    "%s: unexpected cmsg_len %d != %zu",
				    __func__, cmsg->cmsg_len,
				    CMSG_LEN(2 * sizeof(int)));
				continue;
			}
			memcpy(&bi->bi_fd, CMSG_DATA(cmsg), sizeof(bi->bi_fd));
			got |= GOT_FD;
			break;
#ifdef CRED_MESSAGE
		case CRED_MESSAGE:
			sc = (void *)CMSG_DATA(cmsg);
			bi->bi_uid = sc->CRED_SC_UID;
			bi->bi_gid = sc->CRED_SC_GID;
			got |= GOT_CRED;
			break;
#endif
		default:
			bl_log(b->b_fun, LOG_ERR,
			    "%s: unexpected cmsg_type %d",
			    __func__, cmsg->cmsg_type);
			continue;
		}

	}

	if (got != (GOT_CRED|GOT_FD)) {
		bl_log(b->b_fun, LOG_ERR, "message missing %s %s", 
#if GOT_CRED != 0
		    (got & GOT_CRED) == 0 ? "cred" :
#endif
		    "", (got & GOT_FD) == 0 ? "fd" : "");
			
		return NULL;
	}

	if ((size_t)rlen <= sizeof(ub.bl)) {
		bl_log(b->b_fun, LOG_ERR, "message too short %zd", rlen);
		return NULL;
	}

	if (ub.bl.bl_version != BL_VERSION) {
		bl_log(b->b_fun, LOG_ERR, "bad version %d", ub.bl.bl_version);
		return NULL;
	}

	bi->bi_type = ub.bl.bl_type;
	bi->bi_slen = ub.bl.bl_salen;
	bi->bi_ss = ub.bl.bl_ss;
#ifndef CRED_MESSAGE
	bi->bi_uid = -1;
	bi->bi_gid = -1;
#endif
	strlcpy(bi->bi_msg, ub.bl.bl_data, MIN(sizeof(bi->bi_msg),
	    ((size_t)rlen - sizeof(ub.bl) + 1)));
	return bi;
}