src/common/unix.c

   1 /*
   2  * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
   3  * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *
   5  * SPDX-License-Identifier: GPL-2.0-only
   6  *
   7  */
   8
   9 #define _LGPL_SOURCE
  10 #include <assert.h>
  11 #include <limits.h>
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <sys/stat.h>
  16 #include <sys/types.h>
  17 #include <unistd.h>
  18 #include <errno.h>
  19
  20 #include <common/common.h>
  21 #include <common/sessiond-comm/sessiond-comm.h>
  22
  23 #include "unix.h"
  24
  25 /*
  26  * Connect to unix socket using the path name.
  27  */
  28 LTTNG_HIDDEN
  29 int lttcomm_connect_unix_sock(const char *pathname)
  30 {
  31         struct sockaddr_un s_un;
  32         int fd, ret, closeret;
  33
  34         if (strlen(pathname) >= sizeof(s_un.sun_path)) {
  35                 ERR("unix socket address (\"%s\") is longer than the platform's limit (%zu > %zu).",
  36                                 pathname, strlen(pathname) + 1,
  37                                 sizeof(s_un.sun_path));
  38                 ret = -ENAMETOOLONG;
  39                 goto error;
  40         }
  41
  42         fd = socket(PF_UNIX, SOCK_STREAM, 0);
  43         if (fd < 0) {
  44                 PERROR("socket");
  45                 ret = fd;
  46                 goto error;
  47         }
  48
  49         memset(&s_un, 0, sizeof(s_un));
  50         s_un.sun_family = AF_UNIX;
  51         strncpy(s_un.sun_path, pathname, sizeof(s_un.sun_path));
  52         s_un.sun_path[sizeof(s_un.sun_path) - 1] = '\0';
  53
  54         ret = connect(fd, (struct sockaddr *) &s_un, sizeof(s_un));
  55         if (ret < 0) {
  56                 /*
  57                  * Don't print message on connect error, because connect is used in
  58                  * normal execution to detect if sessiond is alive.
  59                  */
  60                 goto error_connect;
  61         }
  62
  63         return fd;
  64
  65 error_connect:
  66         closeret = close(fd);
  67         if (closeret) {
  68                 PERROR("close");
  69         }
  70 error:
  71         return ret;
  72 }
  73
  74 /*
  75  * Do an accept(2) on the sock and return the new file descriptor. The socket
  76  * MUST be bind(2) before.
  77  */
  78 LTTNG_HIDDEN
  79 int lttcomm_accept_unix_sock(int sock)
  80 {
  81         int new_fd;
  82         struct sockaddr_un s_un;
  83         socklen_t len = sizeof(s_un);
  84
  85         /* Blocking call */
  86         new_fd = accept(sock, (struct sockaddr *) &s_un, &len);
  87         if (new_fd < 0) {
  88                 PERROR("accept");
  89         }
  90
  91         return new_fd;
  92 }
  93
  94 LTTNG_HIDDEN
  95 int lttcomm_create_anon_unix_socketpair(int *fds)
  96 {
  97         if (socketpair(PF_UNIX, SOCK_STREAM, 0, fds) < 0) {
  98                 PERROR("socketpair");
  99                 return -1;
 100         }
 101         return 0;
 102 }
 103
 104 /*
 105  * Creates a AF_UNIX local socket using pathname bind the socket upon creation
 106  * and return the fd.
 107  */
 108 LTTNG_HIDDEN
 109 int lttcomm_create_unix_sock(const char *pathname)
 110 {
 111         struct sockaddr_un s_un;
 112         int fd = -1;
 113         int ret = -1;
 114
 115         if (strlen(pathname) >= sizeof(s_un.sun_path)) {
 116                 ERR("unix socket address (\"%s\") is longer than the platform's limit (%zu > %zu).",
 117                                 pathname, strlen(pathname) + 1,
 118                                 sizeof(s_un.sun_path));
 119                 ret = -ENAMETOOLONG;
 120                 goto error;
 121         }
 122
 123         /* Create server socket */
 124         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 125                 PERROR("socket");
 126                 goto error;
 127         }
 128
 129         memset(&s_un, 0, sizeof(s_un));
 130         s_un.sun_family = AF_UNIX;
 131         strncpy(s_un.sun_path, pathname, sizeof(s_un.sun_path));
 132         s_un.sun_path[sizeof(s_un.sun_path) - 1] = '\0';
 133
 134         /* Unlink the old file if present */
 135         (void) unlink(pathname);
 136         ret = bind(fd, (struct sockaddr *) &s_un, sizeof(s_un));
 137         if (ret < 0) {
 138                 PERROR("bind");
 139                 goto error;
 140         }
 141
 142         return fd;
 143
 144 error:
 145         if (fd >= 0) {
 146                 if (close(fd) < 0) {
 147                         PERROR("close create unix sock");
 148                 }
 149         }
 150         return ret;
 151 }
 152
 153 /*
 154  * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
 155  */
 156 LTTNG_HIDDEN
 157 int lttcomm_listen_unix_sock(int sock)
 158 {
 159         int ret;
 160
 161         ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
 162         if (ret < 0) {
 163                 PERROR("listen");
 164         }
 165
 166         return ret;
 167 }
 168
 169 /*
 170  * Receive data of size len in put that data into the buf param. Using recvmsg
 171  * API.
 172  *
 173  * Return the size of received data.
 174  */
 175 LTTNG_HIDDEN
 176 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 177 {
 178         struct msghdr msg;
 179         struct iovec iov[1];
 180         ssize_t ret = -1;
 181         size_t len_last;
 182
 183         memset(&msg, 0, sizeof(msg));
 184
 185         iov[0].iov_base = buf;
 186         iov[0].iov_len = len;
 187         msg.msg_iov = iov;
 188         msg.msg_iovlen = 1;
 189
 190         do {
 191                 len_last = iov[0].iov_len;
 192                 ret = lttng_recvmsg_nosigpipe(sock, &msg);
 193                 if (ret > 0) {
 194                         iov[0].iov_base += ret;
 195                         iov[0].iov_len -= ret;
 196                         assert(ret <= len_last);
 197                 }
 198         } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
 199         if (ret < 0) {
 200                 PERROR("recvmsg");
 201         } else if (ret > 0) {
 202                 ret = len;
 203         }
 204         /* Else ret = 0 meaning an orderly shutdown. */
 205
 206         return ret;
 207 }
 208
 209 /*
 210  * Receive data of size len in put that data into the buf param. Using recvmsg
 211  * API. Only use with sockets set in non-blocking mode.
 212  *
 213  * Return the size of received data.
 214  */
 215 LTTNG_HIDDEN
 216 ssize_t lttcomm_recv_unix_sock_non_block(int sock, void *buf, size_t len)
 217 {
 218         struct msghdr msg;
 219         struct iovec iov[1];
 220         ssize_t ret;
 221
 222         memset(&msg, 0, sizeof(msg));
 223
 224         iov[0].iov_base = buf;
 225         iov[0].iov_len = len;
 226         msg.msg_iov = iov;
 227         msg.msg_iovlen = 1;
 228
 229 retry:
 230         ret = lttng_recvmsg_nosigpipe(sock, &msg);
 231         if (ret < 0) {
 232                 if (errno == EINTR) {
 233                         goto retry;
 234                 } else {
 235                         /* We consider EPIPE and EAGAIN as expected. */
 236                         if (!lttng_opt_quiet &&
 237                                         (errno != EPIPE && errno != EAGAIN)) {
 238                                 PERROR("recvmsg");
 239                         }
 240                         goto end;
 241                 }
 242         }
 243         ret = len;
 244 end:
 245         return ret;
 246 }
 247
 248 /*
 249  * Send buf data of size len. Using sendmsg API.
 250  *
 251  * Return the size of sent data.
 252  */
 253 LTTNG_HIDDEN
 254 ssize_t lttcomm_send_unix_sock(int sock, const void *buf, size_t len)
 255 {
 256         struct msghdr msg;
 257         struct iovec iov[1];
 258         ssize_t ret;
 259
 260         memset(&msg, 0, sizeof(msg));
 261
 262         iov[0].iov_base = (void *) buf;
 263         iov[0].iov_len = len;
 264         msg.msg_iov = iov;
 265         msg.msg_iovlen = 1;
 266
 267         while (iov[0].iov_len) {
 268                 ret = sendmsg(sock, &msg, 0);
 269                 if (ret < 0) {
 270                         if (errno == EINTR) {
 271                                 continue;
 272                         } else {
 273                                 /*
 274                                  * Only warn about EPIPE when quiet mode is
 275                                  * deactivated.
 276                                  * We consider EPIPE as expected.
 277                                  */
 278                                 if (errno != EPIPE || !lttng_opt_quiet) {
 279                                         PERROR("sendmsg");
 280                                 }
 281                                 goto end;
 282                         }
 283                 }
 284                 iov[0].iov_len -= ret;
 285                 iov[0].iov_base += ret;
 286         }
 287         ret = len;
 288 end:
 289         return ret;
 290 }
 291
 292 /*
 293  * Send buf data of size len. Using sendmsg API.
 294  * Only use with non-blocking sockets. The difference with the blocking version
 295  * of the function is that this one does not retry to send on partial sends,
 296  * except if the interruption was caused by a signal (EINTR).
 297  *
 298  * Return the size of sent data.
 299  */
 300 LTTNG_HIDDEN
 301 ssize_t lttcomm_send_unix_sock_non_block(int sock, const void *buf, size_t len)
 302 {
 303         struct msghdr msg;
 304         struct iovec iov[1];
 305         ssize_t ret;
 306
 307         memset(&msg, 0, sizeof(msg));
 308
 309         iov[0].iov_base = (void *) buf;
 310         iov[0].iov_len = len;
 311         msg.msg_iov = iov;
 312         msg.msg_iovlen = 1;
 313
 314 retry:
 315         ret = sendmsg(sock, &msg, 0);
 316         if (ret < 0) {
 317                 if (errno == EINTR) {
 318                         goto retry;
 319                 } else {
 320                         /* We consider EPIPE and EAGAIN as expected. */
 321                         if (!lttng_opt_quiet &&
 322                                         (errno != EPIPE && errno != EAGAIN)) {
 323                                 PERROR("sendmsg");
 324                         }
 325                         goto end;
 326                 }
 327         }
 328         ret = len;
 329 end:
 330         return ret;
 331 }
 332
 333 /*
 334  * Shutdown cleanly a unix socket.
 335  */
 336 LTTNG_HIDDEN
 337 int lttcomm_close_unix_sock(int sock)
 338 {
 339         int ret, closeret;
 340
 341         /* Shutdown receptions and transmissions */
 342         ret = shutdown(sock, SHUT_RDWR);
 343         if (ret < 0) {
 344                 PERROR("shutdown");
 345         }
 346
 347         closeret = close(sock);
 348         if (closeret) {
 349                 PERROR("close");
 350         }
 351
 352         return ret;
 353 }
 354
 355 /*
 356  * Send a message accompanied by fd(s) over a unix socket.
 357  *
 358  * Returns the size of data sent, or negative error value.
 359  */
 360 LTTNG_HIDDEN
 361 ssize_t lttcomm_send_fds_unix_sock(int sock, const int *fds, size_t nb_fd)
 362 {
 363         struct msghdr msg;
 364         struct cmsghdr *cmptr;
 365         struct iovec iov[1];
 366         ssize_t ret = -1;
 367         unsigned int sizeof_fds = nb_fd * sizeof(int);
 368         char tmp[CMSG_SPACE(sizeof_fds)];
 369         char dummy = 0;
 370
 371         memset(&msg, 0, sizeof(msg));
 372         memset(tmp, 0, sizeof(tmp));
 373
 374         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 375                 return -EINVAL;
 376
 377         msg.msg_control = (caddr_t)tmp;
 378         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 379
 380         cmptr = CMSG_FIRSTHDR(&msg);
 381         if (!cmptr) {
 382                 return -1;
 383         }
 384
 385         cmptr->cmsg_level = SOL_SOCKET;
 386         cmptr->cmsg_type = SCM_RIGHTS;
 387         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 388         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 389         /* Sum of the length of all control messages in the buffer: */
 390         msg.msg_controllen = cmptr->cmsg_len;
 391
 392         iov[0].iov_base = &dummy;
 393         iov[0].iov_len = 1;
 394         msg.msg_iov = iov;
 395         msg.msg_iovlen = 1;
 396
 397         do {
 398                 ret = sendmsg(sock, &msg, 0);
 399         } while (ret < 0 && errno == EINTR);
 400         if (ret < 0) {
 401                 /*
 402                  * Only warn about EPIPE when quiet mode is deactivated.
 403                  * We consider EPIPE as expected.
 404                  */
 405                 if (errno != EPIPE || !lttng_opt_quiet) {
 406                         PERROR("sendmsg");
 407                 }
 408         }
 409         return ret;
 410 }
 411
 412 /*
 413  * Recv a message accompanied by fd(s) from a unix socket.
 414  *
 415  * Returns the size of received data, or negative error value.
 416  *
 417  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 418  * actually received in nb_fd.
 419  */
 420 LTTNG_HIDDEN
 421 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 422 {
 423         struct iovec iov[1];
 424         ssize_t ret = 0;
 425         struct cmsghdr *cmsg;
 426         size_t sizeof_fds = nb_fd * sizeof(int);
 427
 428 #ifdef __linux__
 429 /* Account for the struct ucred cmsg in the buffer size */
 430 #define LTTNG_SOCK_RECV_FDS_BUF_SIZE CMSG_SPACE(sizeof_fds) + CMSG_SPACE(sizeof(struct ucred))
 431 #else
 432 #define LTTNG_SOCK_RECV_FDS_BUF_SIZE CMSG_SPACE(sizeof_fds)
 433 #endif /* __linux__ */
 434
 435         char recv_buf[LTTNG_SOCK_RECV_FDS_BUF_SIZE];
 436         struct msghdr msg;
 437         char dummy;
 438
 439         memset(&msg, 0, sizeof(msg));
 440
 441         /* Prepare to receive the structures */
 442         iov[0].iov_base = &dummy;
 443         iov[0].iov_len = 1;
 444         msg.msg_iov = iov;
 445         msg.msg_iovlen = 1;
 446
 447         cmsg = (struct cmsghdr *) recv_buf;
 448         cmsg->cmsg_len = CMSG_LEN(sizeof_fds);
 449         cmsg->cmsg_level = SOL_SOCKET;
 450         cmsg->cmsg_type = SCM_RIGHTS;
 451
 452         msg.msg_control = cmsg;
 453         msg.msg_controllen = CMSG_LEN(sizeof(recv_buf));
 454         msg.msg_flags = 0;
 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
 464         if (ret != 1) {
 465                 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 466                                 ret, 1);
 467                 goto end;
 468         }
 469
 470         if (msg.msg_flags & MSG_CTRUNC) {
 471                 fprintf(stderr, "Error: Control message truncated.\n");
 472                 ret = -1;
 473                 goto end;
 474         }
 475
 476         /*
 477          * If the socket was configured with SO_PASSCRED, the kernel will add a
 478          * control message (cmsg) to the ancillary data of the unix socket. We
 479          * need to expect a cmsg of the SCM_CREDENTIALS as the first control
 480          * message.
 481          */
 482         for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
 483                 if (cmsg->cmsg_level != SOL_SOCKET) {
 484                         fprintf(stderr, "Error: The socket needs to be of type SOL_SOCKET\n");
 485                         ret = -1;
 486                         goto end;
 487                 }
 488                 if (cmsg->cmsg_type == SCM_RIGHTS) {
 489                         /*
 490                          * We found the controle message for file descriptors,
 491                          * now copy the fds to the fds ptr and return success.
 492                          */
 493                         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 494                                 fprintf(stderr, "Error: Received %zu bytes of"
 495                                         "ancillary data for FDs, expected %zu\n",
 496                                         (size_t) cmsg->cmsg_len,
 497                                         (size_t) CMSG_LEN(sizeof_fds));
 498                                 ret = -1;
 499                                 goto end;
 500                         }
 501                         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 502                         ret = sizeof_fds;
 503                         goto end;
 504                 }
 505 #ifdef __linux__
 506                 if (cmsg->cmsg_type == SCM_CREDENTIALS) {
 507                         /*
 508                          * Expect credentials to be sent when expecting fds even
 509                          * if no credential were include in the send(). The
 510                          * kernel adds them...
 511                          */
 512                         ret = -1;
 513                 }
 514 #endif /* __linux__ */
 515         }
 516 end:
 517         return ret;
 518 }
 519
 520 /*
 521  * Send a message with credentials over a unix socket.
 522  *
 523  * Returns the size of data sent, or negative error value.
 524  */
 525 LTTNG_HIDDEN
 526 ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
 527 {
 528         struct msghdr msg;
 529         struct iovec iov[1];
 530         ssize_t ret = -1;
 531 #ifdef __linux__
 532         struct cmsghdr *cmptr;
 533         size_t sizeof_cred = sizeof(lttng_sock_cred);
 534         char anc_buf[CMSG_SPACE(sizeof_cred)];
 535         lttng_sock_cred *creds;
 536
 537         memset(anc_buf, 0, CMSG_SPACE(sizeof_cred) * sizeof(char));
 538 #endif /* __linux__ */
 539
 540         memset(&msg, 0, sizeof(msg));
 541
 542         iov[0].iov_base = buf;
 543         iov[0].iov_len = len;
 544         msg.msg_iov = iov;
 545         msg.msg_iovlen = 1;
 546
 547 #ifdef __linux__
 548         msg.msg_control = (caddr_t) anc_buf;
 549         msg.msg_controllen = CMSG_LEN(sizeof_cred);
 550
 551         cmptr = CMSG_FIRSTHDR(&msg);
 552         if (!cmptr) {
 553                 return -1;
 554         }
 555         cmptr->cmsg_level = SOL_SOCKET;
 556         cmptr->cmsg_type = LTTNG_SOCK_CREDS;
 557         cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
 558
 559         creds = (lttng_sock_cred*) CMSG_DATA(cmptr);
 560
 561         LTTNG_SOCK_SET_UID_CRED(creds, geteuid());
 562         LTTNG_SOCK_SET_GID_CRED(creds, getegid());
 563         LTTNG_SOCK_SET_PID_CRED(creds, getpid());
 564 #endif /* __linux__ */
 565
 566         do {
 567                 ret = sendmsg(sock, &msg, 0);
 568         } while (ret < 0 && errno == EINTR);
 569         if (ret < 0) {
 570                 /*
 571                  * Only warn about EPIPE when quiet mode is deactivated.
 572                  * We consider EPIPE as expected.
 573                  */
 574                 if (errno != EPIPE || !lttng_opt_quiet) {
 575                         PERROR("sendmsg");
 576                 }
 577         }
 578         return ret;
 579 }
 580
 581 /*
 582  * Recv a message accompanied with credentials from a unix socket.
 583  *
 584  * Returns the size of received data, or negative error value.
 585  */
 586 LTTNG_HIDDEN
 587 ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
 588                 lttng_sock_cred *creds)
 589 {
 590         struct msghdr msg;
 591         struct iovec iov[1];
 592         ssize_t ret;
 593         size_t len_last;
 594 #ifdef __linux__
 595         struct cmsghdr *cmptr;
 596         size_t sizeof_cred = sizeof(lttng_sock_cred);
 597         char anc_buf[CMSG_SPACE(sizeof_cred)];
 598 #endif  /* __linux__ */
 599
 600         memset(&msg, 0, sizeof(msg));
 601
 602         /* Not allowed */
 603         if (creds == NULL) {
 604                 ret = -1;
 605                 goto end;
 606         }
 607
 608         /* Prepare to receive the structures */
 609         iov[0].iov_base = buf;
 610         iov[0].iov_len = len;
 611         msg.msg_iov = iov;
 612         msg.msg_iovlen = 1;
 613
 614 #ifdef __linux__
 615         msg.msg_control = anc_buf;
 616         msg.msg_controllen = sizeof(anc_buf);
 617 #endif /* __linux__ */
 618
 619         do {
 620                 len_last = iov[0].iov_len;
 621                 ret = recvmsg(sock, &msg, 0);
 622                 if (ret > 0) {
 623                         iov[0].iov_base += ret;
 624                         iov[0].iov_len -= ret;
 625                         assert(ret <= len_last);
 626                 }
 627         } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
 628         if (ret < 0) {
 629                 PERROR("recvmsg fds");
 630                 goto end;
 631         } else if (ret > 0) {
 632                 ret = len;
 633         }
 634         /* Else ret = 0 meaning an orderly shutdown. */
 635
 636 #ifdef __linux__
 637         if (msg.msg_flags & MSG_CTRUNC) {
 638                 fprintf(stderr, "Error: Control message truncated.\n");
 639                 ret = -1;
 640                 goto end;
 641         }
 642
 643         cmptr = CMSG_FIRSTHDR(&msg);
 644         if (cmptr == NULL) {
 645                 fprintf(stderr, "Error: Invalid control message header\n");
 646                 ret = -1;
 647                 goto end;
 648         }
 649
 650         if (cmptr->cmsg_level != SOL_SOCKET ||
 651                         cmptr->cmsg_type != LTTNG_SOCK_CREDS) {
 652                 fprintf(stderr, "Didn't received any credentials\n");
 653                 ret = -1;
 654                 goto end;
 655         }
 656
 657         if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
 658                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 659                                 (size_t) cmptr->cmsg_len, (size_t) CMSG_LEN(sizeof_cred));
 660                 ret = -1;
 661                 goto end;
 662         }
 663
 664         memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
 665 #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__))
 666         {
 667                 int peer_ret;
 668
 669                 peer_ret = getpeereid(sock, &creds->uid, &creds->gid);
 670                 if (peer_ret != 0) {
 671                         return peer_ret;
 672                 }
 673         }
 674 #else
 675 #error "Please implement credential support for your OS."
 676 #endif  /* __linux__ */
 677
 678 end:
 679         return ret;
 680 }
 681
 682 /*
 683  * Set socket option to use credentials passing.
 684  */
 685 #ifdef __linux__
 686 LTTNG_HIDDEN
 687 int lttcomm_setsockopt_creds_unix_sock(int sock)
 688 {
 689         int ret, on = 1;
 690
 691         /* Set socket for credentials retrieval */
 692         ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 693         if (ret < 0) {
 694                 PERROR("setsockopt creds unix sock");
 695         }
 696         return ret;
 697 }
 698 #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__))
 699 LTTNG_HIDDEN
 700 int lttcomm_setsockopt_creds_unix_sock(int sock)
 701 {
 702         return 0;
 703 }
 704 #else
 705 #error "Please implement credential support for your OS."
 706 #endif /* __linux__ */