Fix: report an error if unix socket address is too long
[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 * Send buf data of size len. Using sendmsg API.
221 *
222 * Return the size of sent data.
223 */
224 LTTNG_HIDDEN
225 ssize_t lttcomm_send_unix_sock(int sock, const void *buf, size_t len)
226 {
227 struct msghdr msg;
228 struct iovec iov[1];
229 ssize_t ret = -1;
230
231 memset(&msg, 0, sizeof(msg));
232
233 iov[0].iov_base = (void *) buf;
234 iov[0].iov_len = len;
235 msg.msg_iov = iov;
236 msg.msg_iovlen = 1;
237
238 ret = sendmsg(sock, &msg, 0);
239 if (ret < 0) {
240 /*
241 * Only warn about EPIPE when quiet mode is deactivated.
242 * We consider EPIPE as expected.
243 */
244 if (errno != EPIPE || !lttng_opt_quiet) {
245 PERROR("sendmsg");
246 }
247 }
248
249 return ret;
250 }
251
252 /*
253 * Shutdown cleanly a unix socket.
254 */
255 LTTNG_HIDDEN
256 int lttcomm_close_unix_sock(int sock)
257 {
258 int ret, closeret;
259
260 /* Shutdown receptions and transmissions */
261 ret = shutdown(sock, SHUT_RDWR);
262 if (ret < 0) {
263 PERROR("shutdown");
264 }
265
266 closeret = close(sock);
267 if (closeret) {
268 PERROR("close");
269 }
270
271 return ret;
272 }
273
274 /*
275 * Send a message accompanied by fd(s) over a unix socket.
276 *
277 * Returns the size of data sent, or negative error value.
278 */
279 LTTNG_HIDDEN
280 ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
281 {
282 struct msghdr msg;
283 struct cmsghdr *cmptr;
284 struct iovec iov[1];
285 ssize_t ret = -1;
286 unsigned int sizeof_fds = nb_fd * sizeof(int);
287 char tmp[CMSG_SPACE(sizeof_fds)];
288 char dummy = 0;
289
290 memset(&msg, 0, sizeof(msg));
291 memset(tmp, 0, CMSG_SPACE(sizeof_fds) * sizeof(char));
292
293 if (nb_fd > LTTCOMM_MAX_SEND_FDS)
294 return -EINVAL;
295
296 msg.msg_control = (caddr_t)tmp;
297 msg.msg_controllen = CMSG_LEN(sizeof_fds);
298
299 cmptr = CMSG_FIRSTHDR(&msg);
300 if (!cmptr) {
301 return -1;
302 }
303 cmptr->cmsg_level = SOL_SOCKET;
304 cmptr->cmsg_type = SCM_RIGHTS;
305 cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
306 memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
307 /* Sum of the length of all control messages in the buffer: */
308 msg.msg_controllen = cmptr->cmsg_len;
309
310 iov[0].iov_base = &dummy;
311 iov[0].iov_len = 1;
312 msg.msg_iov = iov;
313 msg.msg_iovlen = 1;
314
315 do {
316 ret = sendmsg(sock, &msg, 0);
317 } while (ret < 0 && errno == EINTR);
318 if (ret < 0) {
319 /*
320 * Only warn about EPIPE when quiet mode is deactivated.
321 * We consider EPIPE as expected.
322 */
323 if (errno != EPIPE || !lttng_opt_quiet) {
324 PERROR("sendmsg");
325 }
326 }
327 return ret;
328 }
329
330 /*
331 * Recv a message accompanied by fd(s) from a unix socket.
332 *
333 * Returns the size of received data, or negative error value.
334 *
335 * Expect at most "nb_fd" file descriptors. Returns the number of fd
336 * actually received in nb_fd.
337 */
338 LTTNG_HIDDEN
339 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
340 {
341 struct iovec iov[1];
342 ssize_t ret = 0;
343 struct cmsghdr *cmsg;
344 size_t sizeof_fds = nb_fd * sizeof(int);
345 char recv_fd[CMSG_SPACE(sizeof_fds)];
346 struct msghdr msg;
347 char dummy;
348
349 memset(&msg, 0, sizeof(msg));
350
351 /* Prepare to receive the structures */
352 iov[0].iov_base = &dummy;
353 iov[0].iov_len = 1;
354 msg.msg_iov = iov;
355 msg.msg_iovlen = 1;
356 msg.msg_control = recv_fd;
357 msg.msg_controllen = sizeof(recv_fd);
358
359 do {
360 ret = recvmsg(sock, &msg, 0);
361 } while (ret < 0 && errno == EINTR);
362 if (ret < 0) {
363 PERROR("recvmsg fds");
364 goto end;
365 }
366 if (ret != 1) {
367 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
368 ret, 1);
369 goto end;
370 }
371 if (msg.msg_flags & MSG_CTRUNC) {
372 fprintf(stderr, "Error: Control message truncated.\n");
373 ret = -1;
374 goto end;
375 }
376 cmsg = CMSG_FIRSTHDR(&msg);
377 if (!cmsg) {
378 fprintf(stderr, "Error: Invalid control message header\n");
379 ret = -1;
380 goto end;
381 }
382 if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
383 fprintf(stderr, "Didn't received any fd\n");
384 ret = -1;
385 goto end;
386 }
387 if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
388 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
389 (size_t) cmsg->cmsg_len, (size_t) CMSG_LEN(sizeof_fds));
390 ret = -1;
391 goto end;
392 }
393 memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
394 ret = sizeof_fds;
395 end:
396 return ret;
397 }
398
399 /*
400 * Send a message with credentials over a unix socket.
401 *
402 * Returns the size of data sent, or negative error value.
403 */
404 LTTNG_HIDDEN
405 ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
406 {
407 struct msghdr msg;
408 struct iovec iov[1];
409 ssize_t ret = -1;
410 #ifdef __linux__
411 struct cmsghdr *cmptr;
412 size_t sizeof_cred = sizeof(lttng_sock_cred);
413 char anc_buf[CMSG_SPACE(sizeof_cred)];
414 lttng_sock_cred *creds;
415
416 memset(anc_buf, 0, CMSG_SPACE(sizeof_cred) * sizeof(char));
417 #endif /* __linux__ */
418
419 memset(&msg, 0, sizeof(msg));
420
421 iov[0].iov_base = buf;
422 iov[0].iov_len = len;
423 msg.msg_iov = iov;
424 msg.msg_iovlen = 1;
425
426 #ifdef __linux__
427 msg.msg_control = (caddr_t) anc_buf;
428 msg.msg_controllen = CMSG_LEN(sizeof_cred);
429
430 cmptr = CMSG_FIRSTHDR(&msg);
431 if (!cmptr) {
432 return -1;
433 }
434 cmptr->cmsg_level = SOL_SOCKET;
435 cmptr->cmsg_type = LTTNG_SOCK_CREDS;
436 cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
437
438 creds = (lttng_sock_cred*) CMSG_DATA(cmptr);
439
440 LTTNG_SOCK_SET_UID_CRED(creds, geteuid());
441 LTTNG_SOCK_SET_GID_CRED(creds, getegid());
442 LTTNG_SOCK_SET_PID_CRED(creds, getpid());
443 #endif /* __linux__ */
444
445 do {
446 ret = sendmsg(sock, &msg, 0);
447 } while (ret < 0 && errno == EINTR);
448 if (ret < 0) {
449 /*
450 * Only warn about EPIPE when quiet mode is deactivated.
451 * We consider EPIPE as expected.
452 */
453 if (errno != EPIPE || !lttng_opt_quiet) {
454 PERROR("sendmsg");
455 }
456 }
457 return ret;
458 }
459
460 /*
461 * Recv a message accompanied with credentials from a unix socket.
462 *
463 * Returns the size of received data, or negative error value.
464 */
465 LTTNG_HIDDEN
466 ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
467 lttng_sock_cred *creds)
468 {
469 struct msghdr msg;
470 struct iovec iov[1];
471 ssize_t ret;
472 size_t len_last;
473 #ifdef __linux__
474 struct cmsghdr *cmptr;
475 size_t sizeof_cred = sizeof(lttng_sock_cred);
476 char anc_buf[CMSG_SPACE(sizeof_cred)];
477 #endif /* __linux__ */
478
479 memset(&msg, 0, sizeof(msg));
480
481 /* Not allowed */
482 if (creds == NULL) {
483 ret = -1;
484 goto end;
485 }
486
487 /* Prepare to receive the structures */
488 iov[0].iov_base = buf;
489 iov[0].iov_len = len;
490 msg.msg_iov = iov;
491 msg.msg_iovlen = 1;
492
493 #ifdef __linux__
494 msg.msg_control = anc_buf;
495 msg.msg_controllen = sizeof(anc_buf);
496 #endif /* __linux__ */
497
498 do {
499 len_last = iov[0].iov_len;
500 ret = recvmsg(sock, &msg, 0);
501 if (ret > 0) {
502 iov[0].iov_base += ret;
503 iov[0].iov_len -= ret;
504 assert(ret <= len_last);
505 }
506 } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
507 if (ret < 0) {
508 PERROR("recvmsg fds");
509 goto end;
510 } else if (ret > 0) {
511 ret = len;
512 }
513 /* Else ret = 0 meaning an orderly shutdown. */
514
515 #ifdef __linux__
516 if (msg.msg_flags & MSG_CTRUNC) {
517 fprintf(stderr, "Error: Control message truncated.\n");
518 ret = -1;
519 goto end;
520 }
521
522 cmptr = CMSG_FIRSTHDR(&msg);
523 if (cmptr == NULL) {
524 fprintf(stderr, "Error: Invalid control message header\n");
525 ret = -1;
526 goto end;
527 }
528
529 if (cmptr->cmsg_level != SOL_SOCKET ||
530 cmptr->cmsg_type != LTTNG_SOCK_CREDS) {
531 fprintf(stderr, "Didn't received any credentials\n");
532 ret = -1;
533 goto end;
534 }
535
536 if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
537 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
538 (size_t) cmptr->cmsg_len, (size_t) CMSG_LEN(sizeof_cred));
539 ret = -1;
540 goto end;
541 }
542
543 memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
544 #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__))
545 {
546 int peer_ret;
547
548 peer_ret = getpeereid(sock, &creds->uid, &creds->gid);
549 if (peer_ret != 0) {
550 return peer_ret;
551 }
552 }
553 #else
554 #error "Please implement credential support for your OS."
555 #endif /* __linux__ */
556
557 end:
558 return ret;
559 }
560
561 /*
562 * Set socket option to use credentials passing.
563 */
564 #ifdef __linux__
565 LTTNG_HIDDEN
566 int lttcomm_setsockopt_creds_unix_sock(int sock)
567 {
568 int ret, on = 1;
569
570 /* Set socket for credentials retrieval */
571 ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
572 if (ret < 0) {
573 PERROR("setsockopt creds unix sock");
574 }
575 return ret;
576 }
577 #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__))
578 LTTNG_HIDDEN
579 int lttcomm_setsockopt_creds_unix_sock(int sock)
580 {
581 return 0;
582 }
583 #else
584 #error "Please implement credential support for your OS."
585 #endif /* __linux__ */
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