Add non_block version of functions to UNIX socket wrapper
[lttng-tools.git] / src / common / unix.c
1 /*
2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
3 * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License, version 2 only,
7 * as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
12 * more details.
13 *
14 * You should have received a copy of the GNU General Public License along
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
17 */
18
19 #define _LGPL_SOURCE
20 #include <assert.h>
21 #include <limits.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <sys/stat.h>
26 #include <sys/types.h>
27 #include <unistd.h>
28 #include <errno.h>
29
30 #include <common/common.h>
31 #include <common/sessiond-comm/sessiond-comm.h>
32
33 #include "unix.h"
34
35 /*
36 * Connect to unix socket using the path name.
37 */
38 LTTNG_HIDDEN
39 int lttcomm_connect_unix_sock(const char *pathname)
40 {
41 struct sockaddr_un s_un;
42 int fd, ret, closeret;
43
44 if (strlen(pathname) >= sizeof(s_un.sun_path)) {
45 ERR("unix socket address (\"%s\") is longer than the platform's limit (%zu > %zu).",
46 pathname, strlen(pathname) + 1,
47 sizeof(s_un.sun_path));
48 ret = -ENAMETOOLONG;
49 goto error;
50 }
51
52 fd = socket(PF_UNIX, SOCK_STREAM, 0);
53 if (fd < 0) {
54 PERROR("socket");
55 ret = fd;
56 goto error;
57 }
58
59 memset(&s_un, 0, sizeof(s_un));
60 s_un.sun_family = AF_UNIX;
61 strncpy(s_un.sun_path, pathname, sizeof(s_un.sun_path));
62 s_un.sun_path[sizeof(s_un.sun_path) - 1] = '\0';
63
64 ret = connect(fd, (struct sockaddr *) &s_un, sizeof(s_un));
65 if (ret < 0) {
66 /*
67 * Don't print message on connect error, because connect is used in
68 * normal execution to detect if sessiond is alive.
69 */
70 goto error_connect;
71 }
72
73 return fd;
74
75 error_connect:
76 closeret = close(fd);
77 if (closeret) {
78 PERROR("close");
79 }
80 error:
81 return ret;
82 }
83
84 /*
85 * Do an accept(2) on the sock and return the new file descriptor. The socket
86 * MUST be bind(2) before.
87 */
88 LTTNG_HIDDEN
89 int lttcomm_accept_unix_sock(int sock)
90 {
91 int new_fd;
92 struct sockaddr_un s_un;
93 socklen_t len = sizeof(s_un);
94
95 /* Blocking call */
96 new_fd = accept(sock, (struct sockaddr *) &s_un, &len);
97 if (new_fd < 0) {
98 PERROR("accept");
99 }
100
101 return new_fd;
102 }
103
104 LTTNG_HIDDEN
105 int lttcomm_create_anon_unix_socketpair(int *fds)
106 {
107 if (socketpair(PF_UNIX, SOCK_STREAM, 0, fds) < 0) {
108 PERROR("socketpair");
109 return -1;
110 }
111 return 0;
112 }
113
114 /*
115 * Creates a AF_UNIX local socket using pathname bind the socket upon creation
116 * and return the fd.
117 */
118 LTTNG_HIDDEN
119 int lttcomm_create_unix_sock(const char *pathname)
120 {
121 struct sockaddr_un s_un;
122 int fd = -1;
123 int ret = -1;
124
125 if (strlen(pathname) >= sizeof(s_un.sun_path)) {
126 ERR("unix socket address (\"%s\") is longer than the platform's limit (%zu > %zu).",
127 pathname, strlen(pathname) + 1,
128 sizeof(s_un.sun_path));
129 ret = -ENAMETOOLONG;
130 goto error;
131 }
132
133 /* Create server socket */
134 if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
135 PERROR("socket");
136 goto error;
137 }
138
139 memset(&s_un, 0, sizeof(s_un));
140 s_un.sun_family = AF_UNIX;
141 strncpy(s_un.sun_path, pathname, sizeof(s_un.sun_path));
142 s_un.sun_path[sizeof(s_un.sun_path) - 1] = '\0';
143
144 /* Unlink the old file if present */
145 (void) unlink(pathname);
146 ret = bind(fd, (struct sockaddr *) &s_un, sizeof(s_un));
147 if (ret < 0) {
148 PERROR("bind");
149 goto error;
150 }
151
152 return fd;
153
154 error:
155 if (fd >= 0) {
156 if (close(fd) < 0) {
157 PERROR("close create unix sock");
158 }
159 }
160 return ret;
161 }
162
163 /*
164 * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
165 */
166 LTTNG_HIDDEN
167 int lttcomm_listen_unix_sock(int sock)
168 {
169 int ret;
170
171 ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
172 if (ret < 0) {
173 PERROR("listen");
174 }
175
176 return ret;
177 }
178
179 /*
180 * Receive data of size len in put that data into the buf param. Using recvmsg
181 * API.
182 *
183 * Return the size of received data.
184 */
185 LTTNG_HIDDEN
186 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
187 {
188 struct msghdr msg;
189 struct iovec iov[1];
190 ssize_t ret = -1;
191 size_t len_last;
192
193 memset(&msg, 0, sizeof(msg));
194
195 iov[0].iov_base = buf;
196 iov[0].iov_len = len;
197 msg.msg_iov = iov;
198 msg.msg_iovlen = 1;
199
200 do {
201 len_last = iov[0].iov_len;
202 ret = lttng_recvmsg_nosigpipe(sock, &msg);
203 if (ret > 0) {
204 iov[0].iov_base += ret;
205 iov[0].iov_len -= ret;
206 assert(ret <= len_last);
207 }
208 } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
209 if (ret < 0) {
210 PERROR("recvmsg");
211 } else if (ret > 0) {
212 ret = len;
213 }
214 /* Else ret = 0 meaning an orderly shutdown. */
215
216 return ret;
217 }
218
219 /*
220 * Receive data of size len in put that data into the buf param. Using recvmsg
221 * API. Only use with sockets set in non-blocking mode.
222 *
223 * Return the size of received data.
224 */
225 LTTNG_HIDDEN
226 ssize_t lttcomm_recv_unix_sock_non_block(int sock, void *buf, size_t len)
227 {
228 struct msghdr msg;
229 struct iovec iov[1];
230 ssize_t ret;
231
232 memset(&msg, 0, sizeof(msg));
233
234 iov[0].iov_base = buf;
235 iov[0].iov_len = len;
236 msg.msg_iov = iov;
237 msg.msg_iovlen = 1;
238
239 retry:
240 ret = lttng_recvmsg_nosigpipe(sock, &msg);
241 if (ret < 0) {
242 if (errno == EINTR) {
243 goto retry;
244 } else {
245 /*
246 * Only warn about EPIPE when quiet mode is
247 * deactivated.
248 * We consider EPIPE as expected.
249 */
250 if (errno != EPIPE || !lttng_opt_quiet) {
251 PERROR("recvmsg");
252 }
253 goto end;
254 }
255 }
256 ret = len;
257 end:
258 return ret;
259 }
260
261 /*
262 * Send buf data of size len. Using sendmsg API.
263 *
264 * Return the size of sent data.
265 */
266 LTTNG_HIDDEN
267 ssize_t lttcomm_send_unix_sock(int sock, const void *buf, size_t len)
268 {
269 struct msghdr msg;
270 struct iovec iov[1];
271 ssize_t ret;
272
273 memset(&msg, 0, sizeof(msg));
274
275 iov[0].iov_base = (void *) buf;
276 iov[0].iov_len = len;
277 msg.msg_iov = iov;
278 msg.msg_iovlen = 1;
279
280 while (iov[0].iov_len) {
281 ret = sendmsg(sock, &msg, 0);
282 if (ret < 0) {
283 if (errno == EINTR) {
284 continue;
285 } else {
286 /*
287 * Only warn about EPIPE when quiet mode is
288 * deactivated.
289 * We consider EPIPE as expected.
290 */
291 if (errno != EPIPE || !lttng_opt_quiet) {
292 PERROR("sendmsg");
293 }
294 goto end;
295 }
296 }
297 iov[0].iov_len -= ret;
298 iov[0].iov_base += ret;
299 }
300 ret = len;
301 end:
302 return ret;
303 }
304
305 /*
306 * Send buf data of size len. Using sendmsg API.
307 * Only use with non-blocking sockets. The difference with the blocking version
308 * of the function is that this one does not retry to send on partial sends,
309 * except if the interruption was caused by a signal (EINTR).
310 *
311 * Return the size of sent data.
312 */
313 LTTNG_HIDDEN
314 ssize_t lttcomm_send_unix_sock_non_block(int sock, const void *buf, size_t len)
315 {
316 struct msghdr msg;
317 struct iovec iov[1];
318 ssize_t ret;
319
320 memset(&msg, 0, sizeof(msg));
321
322 iov[0].iov_base = (void *) buf;
323 iov[0].iov_len = len;
324 msg.msg_iov = iov;
325 msg.msg_iovlen = 1;
326
327 retry:
328 ret = sendmsg(sock, &msg, 0);
329 if (ret < 0) {
330 if (errno == EINTR) {
331 goto retry;
332 } else {
333 /*
334 * Only warn about EPIPE when quiet mode is
335 * deactivated.
336 * We consider EPIPE as expected.
337 */
338 if (errno != EPIPE || !lttng_opt_quiet) {
339 PERROR("sendmsg");
340 }
341 goto end;
342 }
343 }
344 ret = len;
345 end:
346 return ret;
347 }
348
349 /*
350 * Shutdown cleanly a unix socket.
351 */
352 LTTNG_HIDDEN
353 int lttcomm_close_unix_sock(int sock)
354 {
355 int ret, closeret;
356
357 /* Shutdown receptions and transmissions */
358 ret = shutdown(sock, SHUT_RDWR);
359 if (ret < 0) {
360 PERROR("shutdown");
361 }
362
363 closeret = close(sock);
364 if (closeret) {
365 PERROR("close");
366 }
367
368 return ret;
369 }
370
371 /*
372 * Send a message accompanied by fd(s) over a unix socket.
373 *
374 * Returns the size of data sent, or negative error value.
375 */
376 LTTNG_HIDDEN
377 ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
378 {
379 struct msghdr msg;
380 struct cmsghdr *cmptr;
381 struct iovec iov[1];
382 ssize_t ret = -1;
383 unsigned int sizeof_fds = nb_fd * sizeof(int);
384 char tmp[CMSG_SPACE(sizeof_fds)];
385 char dummy = 0;
386
387 memset(&msg, 0, sizeof(msg));
388 memset(tmp, 0, CMSG_SPACE(sizeof_fds) * sizeof(char));
389
390 if (nb_fd > LTTCOMM_MAX_SEND_FDS)
391 return -EINVAL;
392
393 msg.msg_control = (caddr_t)tmp;
394 msg.msg_controllen = CMSG_LEN(sizeof_fds);
395
396 cmptr = CMSG_FIRSTHDR(&msg);
397 if (!cmptr) {
398 return -1;
399 }
400 cmptr->cmsg_level = SOL_SOCKET;
401 cmptr->cmsg_type = SCM_RIGHTS;
402 cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
403 memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
404 /* Sum of the length of all control messages in the buffer: */
405 msg.msg_controllen = cmptr->cmsg_len;
406
407 iov[0].iov_base = &dummy;
408 iov[0].iov_len = 1;
409 msg.msg_iov = iov;
410 msg.msg_iovlen = 1;
411
412 do {
413 ret = sendmsg(sock, &msg, 0);
414 } while (ret < 0 && errno == EINTR);
415 if (ret < 0) {
416 /*
417 * Only warn about EPIPE when quiet mode is deactivated.
418 * We consider EPIPE as expected.
419 */
420 if (errno != EPIPE || !lttng_opt_quiet) {
421 PERROR("sendmsg");
422 }
423 }
424 return ret;
425 }
426
427 /*
428 * Recv a message accompanied by fd(s) from a unix socket.
429 *
430 * Returns the size of received data, or negative error value.
431 *
432 * Expect at most "nb_fd" file descriptors. Returns the number of fd
433 * actually received in nb_fd.
434 */
435 LTTNG_HIDDEN
436 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
437 {
438 struct iovec iov[1];
439 ssize_t ret = 0;
440 struct cmsghdr *cmsg;
441 size_t sizeof_fds = nb_fd * sizeof(int);
442 char recv_fd[CMSG_SPACE(sizeof_fds)];
443 struct msghdr msg;
444 char dummy;
445
446 memset(&msg, 0, sizeof(msg));
447
448 /* Prepare to receive the structures */
449 iov[0].iov_base = &dummy;
450 iov[0].iov_len = 1;
451 msg.msg_iov = iov;
452 msg.msg_iovlen = 1;
453 msg.msg_control = recv_fd;
454 msg.msg_controllen = sizeof(recv_fd);
455
456 do {
457 ret = recvmsg(sock, &msg, 0);
458 } while (ret < 0 && errno == EINTR);
459 if (ret < 0) {
460 PERROR("recvmsg fds");
461 goto end;
462 }
463 if (ret != 1) {
464 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
465 ret, 1);
466 goto end;
467 }
468 if (msg.msg_flags & MSG_CTRUNC) {
469 fprintf(stderr, "Error: Control message truncated.\n");
470 ret = -1;
471 goto end;
472 }
473 cmsg = CMSG_FIRSTHDR(&msg);
474 if (!cmsg) {
475 fprintf(stderr, "Error: Invalid control message header\n");
476 ret = -1;
477 goto end;
478 }
479 if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
480 fprintf(stderr, "Didn't received any fd\n");
481 ret = -1;
482 goto end;
483 }
484 if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
485 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
486 (size_t) cmsg->cmsg_len, (size_t) CMSG_LEN(sizeof_fds));
487 ret = -1;
488 goto end;
489 }
490 memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
491 ret = sizeof_fds;
492 end:
493 return ret;
494 }
495
496 /*
497 * Send a message with credentials over a unix socket.
498 *
499 * Returns the size of data sent, or negative error value.
500 */
501 LTTNG_HIDDEN
502 ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
503 {
504 struct msghdr msg;
505 struct iovec iov[1];
506 ssize_t ret = -1;
507 #ifdef __linux__
508 struct cmsghdr *cmptr;
509 size_t sizeof_cred = sizeof(lttng_sock_cred);
510 char anc_buf[CMSG_SPACE(sizeof_cred)];
511 lttng_sock_cred *creds;
512
513 memset(anc_buf, 0, CMSG_SPACE(sizeof_cred) * sizeof(char));
514 #endif /* __linux__ */
515
516 memset(&msg, 0, sizeof(msg));
517
518 iov[0].iov_base = buf;
519 iov[0].iov_len = len;
520 msg.msg_iov = iov;
521 msg.msg_iovlen = 1;
522
523 #ifdef __linux__
524 msg.msg_control = (caddr_t) anc_buf;
525 msg.msg_controllen = CMSG_LEN(sizeof_cred);
526
527 cmptr = CMSG_FIRSTHDR(&msg);
528 if (!cmptr) {
529 return -1;
530 }
531 cmptr->cmsg_level = SOL_SOCKET;
532 cmptr->cmsg_type = LTTNG_SOCK_CREDS;
533 cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
534
535 creds = (lttng_sock_cred*) CMSG_DATA(cmptr);
536
537 LTTNG_SOCK_SET_UID_CRED(creds, geteuid());
538 LTTNG_SOCK_SET_GID_CRED(creds, getegid());
539 LTTNG_SOCK_SET_PID_CRED(creds, getpid());
540 #endif /* __linux__ */
541
542 do {
543 ret = sendmsg(sock, &msg, 0);
544 } while (ret < 0 && errno == EINTR);
545 if (ret < 0) {
546 /*
547 * Only warn about EPIPE when quiet mode is deactivated.
548 * We consider EPIPE as expected.
549 */
550 if (errno != EPIPE || !lttng_opt_quiet) {
551 PERROR("sendmsg");
552 }
553 }
554 return ret;
555 }
556
557 /*
558 * Recv a message accompanied with credentials from a unix socket.
559 *
560 * Returns the size of received data, or negative error value.
561 */
562 LTTNG_HIDDEN
563 ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
564 lttng_sock_cred *creds)
565 {
566 struct msghdr msg;
567 struct iovec iov[1];
568 ssize_t ret;
569 size_t len_last;
570 #ifdef __linux__
571 struct cmsghdr *cmptr;
572 size_t sizeof_cred = sizeof(lttng_sock_cred);
573 char anc_buf[CMSG_SPACE(sizeof_cred)];
574 #endif /* __linux__ */
575
576 memset(&msg, 0, sizeof(msg));
577
578 /* Not allowed */
579 if (creds == NULL) {
580 ret = -1;
581 goto end;
582 }
583
584 /* Prepare to receive the structures */
585 iov[0].iov_base = buf;
586 iov[0].iov_len = len;
587 msg.msg_iov = iov;
588 msg.msg_iovlen = 1;
589
590 #ifdef __linux__
591 msg.msg_control = anc_buf;
592 msg.msg_controllen = sizeof(anc_buf);
593 #endif /* __linux__ */
594
595 do {
596 len_last = iov[0].iov_len;
597 ret = recvmsg(sock, &msg, 0);
598 if (ret > 0) {
599 iov[0].iov_base += ret;
600 iov[0].iov_len -= ret;
601 assert(ret <= len_last);
602 }
603 } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
604 if (ret < 0) {
605 PERROR("recvmsg fds");
606 goto end;
607 } else if (ret > 0) {
608 ret = len;
609 }
610 /* Else ret = 0 meaning an orderly shutdown. */
611
612 #ifdef __linux__
613 if (msg.msg_flags & MSG_CTRUNC) {
614 fprintf(stderr, "Error: Control message truncated.\n");
615 ret = -1;
616 goto end;
617 }
618
619 cmptr = CMSG_FIRSTHDR(&msg);
620 if (cmptr == NULL) {
621 fprintf(stderr, "Error: Invalid control message header\n");
622 ret = -1;
623 goto end;
624 }
625
626 if (cmptr->cmsg_level != SOL_SOCKET ||
627 cmptr->cmsg_type != LTTNG_SOCK_CREDS) {
628 fprintf(stderr, "Didn't received any credentials\n");
629 ret = -1;
630 goto end;
631 }
632
633 if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
634 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
635 (size_t) cmptr->cmsg_len, (size_t) CMSG_LEN(sizeof_cred));
636 ret = -1;
637 goto end;
638 }
639
640 memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
641 #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__))
642 {
643 int peer_ret;
644
645 peer_ret = getpeereid(sock, &creds->uid, &creds->gid);
646 if (peer_ret != 0) {
647 return peer_ret;
648 }
649 }
650 #else
651 #error "Please implement credential support for your OS."
652 #endif /* __linux__ */
653
654 end:
655 return ret;
656 }
657
658 /*
659 * Set socket option to use credentials passing.
660 */
661 #ifdef __linux__
662 LTTNG_HIDDEN
663 int lttcomm_setsockopt_creds_unix_sock(int sock)
664 {
665 int ret, on = 1;
666
667 /* Set socket for credentials retrieval */
668 ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
669 if (ret < 0) {
670 PERROR("setsockopt creds unix sock");
671 }
672 return ret;
673 }
674 #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__))
675 LTTNG_HIDDEN
676 int lttcomm_setsockopt_creds_unix_sock(int sock)
677 {
678 return 0;
679 }
680 #else
681 #error "Please implement credential support for your OS."
682 #endif /* __linux__ */
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