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  * NOTE: EPIPE errors are NOT reported. This call expects the socket to be in a
 214  * poll set. The poll loop will handle the EPIPE original cause.
 215  *
 216  * Return the size of received data.
 217  */
 218 LTTNG_HIDDEN
 219 ssize_t lttcomm_recv_unix_sock_non_block(int sock, void *buf, size_t len)
 220 {
 221         struct msghdr msg;
 222         struct iovec iov[1];
 223         ssize_t ret;
 224
 225         memset(&msg, 0, sizeof(msg));
 226
 227         iov[0].iov_base = buf;
 228         iov[0].iov_len = len;
 229         msg.msg_iov = iov;
 230         msg.msg_iovlen = 1;
 231
 232 retry:
 233         ret = lttng_recvmsg_nosigpipe(sock, &msg);
 234         if (ret < 0) {
 235                 if (errno == EINTR) {
 236                         goto retry;
 237                 } else {
 238                         /*
 239                          * We consider EPIPE and EAGAIN/EWOULDBLOCK as expected.
 240                          */
 241                         if (errno == EAGAIN || errno == EWOULDBLOCK ||
 242                                         errno == EPIPE) {
 243                                 /*
 244                                  * Nothing was recv.
 245                                  */
 246                                 ret = 0;
 247                                 goto end;
 248                         }
 249
 250                         /* Unexpected error */
 251                         PERROR("recvmsg");
 252                         ret = -1;
 253                         goto end;
 254                 }
 255         }
 256
 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  * NOTE: EPIPE errors are NOT reported. This call expects the socket to be in a
 312  * poll set. The poll loop will handle the EPIPE original cause.
 313  *
 314  * Return the size of sent data.
 315  */
 316 LTTNG_HIDDEN
 317 ssize_t lttcomm_send_unix_sock_non_block(int sock, const void *buf, size_t len)
 318 {
 319         struct msghdr msg;
 320         struct iovec iov[1];
 321         ssize_t ret;
 322
 323         memset(&msg, 0, sizeof(msg));
 324
 325         iov[0].iov_base = (void *) buf;
 326         iov[0].iov_len = len;
 327         msg.msg_iov = iov;
 328         msg.msg_iovlen = 1;
 329
 330 retry:
 331         ret = sendmsg(sock, &msg, 0);
 332         if (ret < 0) {
 333                 if (errno == EINTR) {
 334                         goto retry;
 335                 } else {
 336                         /*
 337                          * We consider EPIPE and EAGAIN/EWOULDBLOCK as expected.
 338                          */
 339                         if (errno == EAGAIN || errno == EWOULDBLOCK ||
 340                                         errno == EPIPE) {
 341                                 /*
 342                                  * This can happen in non blocking mode.
 343                                  * Nothing was sent.
 344                                  */
 345                                 ret = 0;
 346                                 goto end;
 347                         }
 348
 349                         /* Unexpected error */
 350                         PERROR("sendmsg");
 351                         ret = -1;
 352                         goto end;
 353                 }
 354         }
 355 end:
 356         return ret;
 357 }
 358
 359 /*
 360  * Shutdown cleanly a unix socket.
 361  */
 362 LTTNG_HIDDEN
 363 int lttcomm_close_unix_sock(int sock)
 364 {
 365         int ret, closeret;
 366
 367         /* Shutdown receptions and transmissions */
 368         ret = shutdown(sock, SHUT_RDWR);
 369         if (ret < 0) {
 370                 PERROR("shutdown");
 371         }
 372
 373         closeret = close(sock);
 374         if (closeret) {
 375                 PERROR("close");
 376         }
 377
 378         return ret;
 379 }
 380
 381 /*
 382  * Send a message accompanied by fd(s) over a unix socket.
 383  *
 384  * Returns the size of data sent, or negative error value.
 385  */
 386 LTTNG_HIDDEN
 387 ssize_t lttcomm_send_fds_unix_sock(int sock, const int *fds, size_t nb_fd)
 388 {
 389         struct msghdr msg;
 390         struct cmsghdr *cmptr;
 391         struct iovec iov[1];
 392         ssize_t ret = -1;
 393         unsigned int sizeof_fds = nb_fd * sizeof(int);
 394         char tmp[CMSG_SPACE(sizeof_fds)];
 395         char dummy = 0;
 396
 397         memset(&msg, 0, sizeof(msg));
 398         memset(tmp, 0, sizeof(tmp));
 399
 400         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 401                 return -EINVAL;
 402
 403         msg.msg_control = (caddr_t)tmp;
 404         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 405
 406         cmptr = CMSG_FIRSTHDR(&msg);
 407         if (!cmptr) {
 408                 return -1;
 409         }
 410
 411         cmptr->cmsg_level = SOL_SOCKET;
 412         cmptr->cmsg_type = SCM_RIGHTS;
 413         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 414         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 415         /* Sum of the length of all control messages in the buffer: */
 416         msg.msg_controllen = cmptr->cmsg_len;
 417
 418         iov[0].iov_base = &dummy;
 419         iov[0].iov_len = 1;
 420         msg.msg_iov = iov;
 421         msg.msg_iovlen = 1;
 422
 423         do {
 424                 ret = sendmsg(sock, &msg, 0);
 425         } while (ret < 0 && errno == EINTR);
 426         if (ret < 0) {
 427                 /*
 428                  * Only warn about EPIPE when quiet mode is deactivated.
 429                  * We consider EPIPE as expected.
 430                  */
 431                 if (errno != EPIPE || !lttng_opt_quiet) {
 432                         PERROR("sendmsg");
 433                 }
 434         }
 435         return ret;
 436 }
 437
 438 /*
 439  * Recv a message accompanied by fd(s) from a unix socket.
 440  *
 441  * Returns the size of received data, or negative error value.
 442  *
 443  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 444  * actually received in nb_fd.
 445  */
 446 LTTNG_HIDDEN
 447 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 448 {
 449         struct iovec iov[1];
 450         ssize_t ret = 0;
 451         struct cmsghdr *cmsg;
 452         size_t sizeof_fds = nb_fd * sizeof(int);
 453
 454 #ifdef __linux__
 455 /* Account for the struct ucred cmsg in the buffer size */
 456 #define LTTNG_SOCK_RECV_FDS_BUF_SIZE CMSG_SPACE(sizeof_fds) + CMSG_SPACE(sizeof(struct ucred))
 457 #else
 458 #define LTTNG_SOCK_RECV_FDS_BUF_SIZE CMSG_SPACE(sizeof_fds)
 459 #endif /* __linux__ */
 460
 461         char recv_buf[LTTNG_SOCK_RECV_FDS_BUF_SIZE];
 462         struct msghdr msg;
 463         char dummy;
 464
 465         memset(&msg, 0, sizeof(msg));
 466
 467         /* Prepare to receive the structures */
 468         iov[0].iov_base = &dummy;
 469         iov[0].iov_len = 1;
 470         msg.msg_iov = iov;
 471         msg.msg_iovlen = 1;
 472
 473         cmsg = (struct cmsghdr *) recv_buf;
 474         cmsg->cmsg_len = CMSG_LEN(sizeof_fds);
 475         cmsg->cmsg_level = SOL_SOCKET;
 476         cmsg->cmsg_type = SCM_RIGHTS;
 477
 478         msg.msg_control = cmsg;
 479         msg.msg_controllen = CMSG_LEN(sizeof(recv_buf));
 480         msg.msg_flags = 0;
 481
 482         do {
 483                 ret = recvmsg(sock, &msg, 0);
 484         } while (ret < 0 && errno == EINTR);
 485         if (ret < 0) {
 486                 PERROR("recvmsg fds");
 487                 goto end;
 488         }
 489
 490         if (ret != 1) {
 491                 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 492                                 ret, 1);
 493                 goto end;
 494         }
 495
 496         if (msg.msg_flags & MSG_CTRUNC) {
 497                 fprintf(stderr, "Error: Control message truncated.\n");
 498                 ret = -1;
 499                 goto end;
 500         }
 501
 502         /*
 503          * If the socket was configured with SO_PASSCRED, the kernel will add a
 504          * control message (cmsg) to the ancillary data of the unix socket. We
 505          * need to expect a cmsg of the SCM_CREDENTIALS as the first control
 506          * message.
 507          */
 508         for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
 509                 if (cmsg->cmsg_level != SOL_SOCKET) {
 510                         fprintf(stderr, "Error: The socket needs to be of type SOL_SOCKET\n");
 511                         ret = -1;
 512                         goto end;
 513                 }
 514                 if (cmsg->cmsg_type == SCM_RIGHTS) {
 515                         /*
 516                          * We found the controle message for file descriptors,
 517                          * now copy the fds to the fds ptr and return success.
 518                          */
 519                         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 520                                 fprintf(stderr, "Error: Received %zu bytes of"
 521                                         "ancillary data for FDs, expected %zu\n",
 522                                         (size_t) cmsg->cmsg_len,
 523                                         (size_t) CMSG_LEN(sizeof_fds));
 524                                 ret = -1;
 525                                 goto end;
 526                         }
 527                         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 528                         ret = sizeof_fds;
 529                         goto end;
 530                 }
 531 #ifdef __linux__
 532                 if (cmsg->cmsg_type == SCM_CREDENTIALS) {
 533                         /*
 534                          * Expect credentials to be sent when expecting fds even
 535                          * if no credential were include in the send(). The
 536                          * kernel adds them...
 537                          */
 538                         ret = -1;
 539                 }
 540 #endif /* __linux__ */
 541         }
 542 end:
 543         return ret;
 544 }
 545
 546 /*
 547  * Send a message with credentials over a unix socket.
 548  *
 549  * Returns the size of data sent, or negative error value.
 550  */
 551 LTTNG_HIDDEN
 552 ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
 553 {
 554         struct msghdr msg;
 555         struct iovec iov[1];
 556         ssize_t ret = -1;
 557 #ifdef __linux__
 558         struct cmsghdr *cmptr;
 559         size_t sizeof_cred = sizeof(lttng_sock_cred);
 560         char anc_buf[CMSG_SPACE(sizeof_cred)];
 561         lttng_sock_cred *creds;
 562
 563         memset(anc_buf, 0, CMSG_SPACE(sizeof_cred) * sizeof(char));
 564 #endif /* __linux__ */
 565
 566         memset(&msg, 0, sizeof(msg));
 567
 568         iov[0].iov_base = buf;
 569         iov[0].iov_len = len;
 570         msg.msg_iov = iov;
 571         msg.msg_iovlen = 1;
 572
 573 #ifdef __linux__
 574         msg.msg_control = (caddr_t) anc_buf;
 575         msg.msg_controllen = CMSG_LEN(sizeof_cred);
 576
 577         cmptr = CMSG_FIRSTHDR(&msg);
 578         if (!cmptr) {
 579                 return -1;
 580         }
 581         cmptr->cmsg_level = SOL_SOCKET;
 582         cmptr->cmsg_type = LTTNG_SOCK_CREDS;
 583         cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
 584
 585         creds = (lttng_sock_cred*) CMSG_DATA(cmptr);
 586
 587         LTTNG_SOCK_SET_UID_CRED(creds, geteuid());
 588         LTTNG_SOCK_SET_GID_CRED(creds, getegid());
 589         LTTNG_SOCK_SET_PID_CRED(creds, getpid());
 590 #endif /* __linux__ */
 591
 592         do {
 593                 ret = sendmsg(sock, &msg, 0);
 594         } while (ret < 0 && errno == EINTR);
 595         if (ret < 0) {
 596                 /*
 597                  * Only warn about EPIPE when quiet mode is deactivated.
 598                  * We consider EPIPE as expected.
 599                  */
 600                 if (errno != EPIPE || !lttng_opt_quiet) {
 601                         PERROR("sendmsg");
 602                 }
 603         }
 604         return ret;
 605 }
 606
 607 /*
 608  * Recv a message accompanied with credentials from a unix socket.
 609  *
 610  * Returns the size of received data, or negative error value.
 611  */
 612 LTTNG_HIDDEN
 613 ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
 614                 lttng_sock_cred *creds)
 615 {
 616         struct msghdr msg;
 617         struct iovec iov[1];
 618         ssize_t ret;
 619         size_t len_last;
 620 #ifdef __linux__
 621         struct cmsghdr *cmptr;
 622         size_t sizeof_cred = sizeof(lttng_sock_cred);
 623         char anc_buf[CMSG_SPACE(sizeof_cred)];
 624 #endif  /* __linux__ */
 625
 626         memset(&msg, 0, sizeof(msg));
 627
 628         /* Not allowed */
 629         if (creds == NULL) {
 630                 ret = -1;
 631                 goto end;
 632         }
 633
 634         /* Prepare to receive the structures */
 635         iov[0].iov_base = buf;
 636         iov[0].iov_len = len;
 637         msg.msg_iov = iov;
 638         msg.msg_iovlen = 1;
 639
 640 #ifdef __linux__
 641         msg.msg_control = anc_buf;
 642         msg.msg_controllen = sizeof(anc_buf);
 643 #endif /* __linux__ */
 644
 645         do {
 646                 len_last = iov[0].iov_len;
 647                 ret = recvmsg(sock, &msg, 0);
 648                 if (ret > 0) {
 649                         iov[0].iov_base += ret;
 650                         iov[0].iov_len -= ret;
 651                         assert(ret <= len_last);
 652                 }
 653         } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
 654         if (ret < 0) {
 655                 PERROR("recvmsg fds");
 656                 goto end;
 657         } else if (ret > 0) {
 658                 ret = len;
 659         }
 660         /* Else ret = 0 meaning an orderly shutdown. */
 661
 662 #ifdef __linux__
 663         if (msg.msg_flags & MSG_CTRUNC) {
 664                 fprintf(stderr, "Error: Control message truncated.\n");
 665                 ret = -1;
 666                 goto end;
 667         }
 668
 669         cmptr = CMSG_FIRSTHDR(&msg);
 670         if (cmptr == NULL) {
 671                 fprintf(stderr, "Error: Invalid control message header\n");
 672                 ret = -1;
 673                 goto end;
 674         }
 675
 676         if (cmptr->cmsg_level != SOL_SOCKET ||
 677                         cmptr->cmsg_type != LTTNG_SOCK_CREDS) {
 678                 fprintf(stderr, "Didn't received any credentials\n");
 679                 ret = -1;
 680                 goto end;
 681         }
 682
 683         if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
 684                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 685                                 (size_t) cmptr->cmsg_len, (size_t) CMSG_LEN(sizeof_cred));
 686                 ret = -1;
 687                 goto end;
 688         }
 689
 690         memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
 691 #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__))
 692         {
 693                 int peer_ret;
 694
 695                 peer_ret = getpeereid(sock, &creds->uid, &creds->gid);
 696                 if (peer_ret != 0) {
 697                         return peer_ret;
 698                 }
 699         }
 700 #else
 701 #error "Please implement credential support for your OS."
 702 #endif  /* __linux__ */
 703
 704 end:
 705         return ret;
 706 }
 707
 708 /*
 709  * Set socket option to use credentials passing.
 710  */
 711 #ifdef __linux__
 712 LTTNG_HIDDEN
 713 int lttcomm_setsockopt_creds_unix_sock(int sock)
 714 {
 715         int ret, on = 1;
 716
 717         /* Set socket for credentials retrieval */
 718         ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 719         if (ret < 0) {
 720                 PERROR("setsockopt creds unix sock");
 721         }
 722         return ret;
 723 }
 724 #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__))
 725 LTTNG_HIDDEN
 726 int lttcomm_setsockopt_creds_unix_sock(int sock)
 727 {
 728         return 0;
 729 }
 730 #else
 731 #error "Please implement credential support for your OS."
 732 #endif /* __linux__ */