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  * NOTE: EPIPE errors are NOT reported. This call expects the socket to be in a
 224  * poll set. The poll loop will handle the EPIPE original cause.
 225  *
 226  * Return the size of received data.
 227  */
 228 LTTNG_HIDDEN
 229 ssize_t lttcomm_recv_unix_sock_non_block(int sock, void *buf, size_t len)
 230 {
 231         struct msghdr msg;
 232         struct iovec iov[1];
 233         ssize_t ret;
 234
 235         memset(&msg, 0, sizeof(msg));
 236
 237         iov[0].iov_base = buf;
 238         iov[0].iov_len = len;
 239         msg.msg_iov = iov;
 240         msg.msg_iovlen = 1;
 241
 242 retry:
 243         ret = lttng_recvmsg_nosigpipe(sock, &msg);
 244         if (ret < 0) {
 245                 if (errno == EINTR) {
 246                         goto retry;
 247                 } else {
 248                         /*
 249                          * We consider EPIPE and EAGAIN/EWOULDBLOCK as expected.
 250                          */
 251                         if (errno == EAGAIN || errno == EWOULDBLOCK ||
 252                                         errno == EPIPE) {
 253                                 /*
 254                                  * Nothing was recv.
 255                                  */
 256                                 ret = 0;
 257                                 goto end;
 258                         }
 259
 260                         /* Unexpected error */
 261                         PERROR("recvmsg");
 262                         ret = -1;
 263                         goto end;
 264                 }
 265         }
 266         ret = len;
 267 end:
 268         return ret;
 269 }
 270
 271 /*
 272  * Send buf data of size len. Using sendmsg API.
 273  *
 274  * Return the size of sent data.
 275  */
 276 LTTNG_HIDDEN
 277 ssize_t lttcomm_send_unix_sock(int sock, const void *buf, size_t len)
 278 {
 279         struct msghdr msg;
 280         struct iovec iov[1];
 281         ssize_t ret;
 282
 283         memset(&msg, 0, sizeof(msg));
 284
 285         iov[0].iov_base = (void *) buf;
 286         iov[0].iov_len = len;
 287         msg.msg_iov = iov;
 288         msg.msg_iovlen = 1;
 289
 290         while (iov[0].iov_len) {
 291                 ret = sendmsg(sock, &msg, 0);
 292                 if (ret < 0) {
 293                         if (errno == EINTR) {
 294                                 continue;
 295                         } else {
 296                                 /*
 297                                  * Only warn about EPIPE when quiet mode is
 298                                  * deactivated.
 299                                  * We consider EPIPE as expected.
 300                                  */
 301                                 if (errno != EPIPE || !lttng_opt_quiet) {
 302                                         PERROR("sendmsg");
 303                                 }
 304                                 goto end;
 305                         }
 306                 }
 307                 iov[0].iov_len -= ret;
 308                 iov[0].iov_base += ret;
 309         }
 310         ret = len;
 311 end:
 312         return ret;
 313 }
 314
 315 /*
 316  * Send buf data of size len. Using sendmsg API.
 317  * Only use with non-blocking sockets. The difference with the blocking version
 318  * of the function is that this one does not retry to send on partial sends,
 319  * except if the interruption was caused by a signal (EINTR).
 320  *
 321  * NOTE: EPIPE errors are NOT reported. This call expects the socket to be in a
 322  * poll set. The poll loop will handle the EPIPE original cause.
 323  *
 324  * Return the size of sent data.
 325  */
 326 LTTNG_HIDDEN
 327 ssize_t lttcomm_send_unix_sock_non_block(int sock, const void *buf, size_t len)
 328 {
 329         struct msghdr msg;
 330         struct iovec iov[1];
 331         ssize_t ret;
 332
 333         memset(&msg, 0, sizeof(msg));
 334
 335         iov[0].iov_base = (void *) buf;
 336         iov[0].iov_len = len;
 337         msg.msg_iov = iov;
 338         msg.msg_iovlen = 1;
 339
 340 retry:
 341         ret = sendmsg(sock, &msg, 0);
 342         if (ret < 0) {
 343                 if (errno == EINTR) {
 344                         goto retry;
 345                 } else {
 346                         /*
 347                          * We consider EPIPE and EAGAIN/EWOULDBLOCK as expected.
 348                          */
 349                         if (errno == EAGAIN || errno == EWOULDBLOCK ||
 350                                         errno == EPIPE) {
 351                                 /*
 352                                  * This can happen in non blocking mode.
 353                                  * Nothing was sent.
 354                                  */
 355                                 ret = 0;
 356                                 goto end;
 357                         }
 358
 359                         /* Unexpected error */
 360                         PERROR("sendmsg");
 361                         ret = -1;
 362                         goto end;
 363                 }
 364         }
 365         ret = len;
 366 end:
 367         return ret;
 368 }
 369
 370 /*
 371  * Shutdown cleanly a unix socket.
 372  */
 373 LTTNG_HIDDEN
 374 int lttcomm_close_unix_sock(int sock)
 375 {
 376         int ret, closeret;
 377
 378         /* Shutdown receptions and transmissions */
 379         ret = shutdown(sock, SHUT_RDWR);
 380         if (ret < 0) {
 381                 PERROR("shutdown");
 382         }
 383
 384         closeret = close(sock);
 385         if (closeret) {
 386                 PERROR("close");
 387         }
 388
 389         return ret;
 390 }
 391
 392 /*
 393  * Send a message accompanied by fd(s) over a unix socket.
 394  *
 395  * Returns the size of data sent, or negative error value.
 396  */
 397 LTTNG_HIDDEN
 398 ssize_t lttcomm_send_fds_unix_sock(int sock, const int *fds, size_t nb_fd)
 399 {
 400         struct msghdr msg;
 401         struct cmsghdr *cmptr;
 402         struct iovec iov[1];
 403         ssize_t ret = -1;
 404         unsigned int sizeof_fds = nb_fd * sizeof(int);
 405         char tmp[CMSG_SPACE(sizeof_fds)];
 406         char dummy = 0;
 407
 408         memset(&msg, 0, sizeof(msg));
 409         memset(tmp, 0, sizeof(tmp));
 410
 411         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 412                 return -EINVAL;
 413
 414         msg.msg_control = (caddr_t)tmp;
 415         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 416
 417         cmptr = CMSG_FIRSTHDR(&msg);
 418         if (!cmptr) {
 419                 return -1;
 420         }
 421
 422         cmptr->cmsg_level = SOL_SOCKET;
 423         cmptr->cmsg_type = SCM_RIGHTS;
 424         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 425         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 426         /* Sum of the length of all control messages in the buffer: */
 427         msg.msg_controllen = cmptr->cmsg_len;
 428
 429         iov[0].iov_base = &dummy;
 430         iov[0].iov_len = 1;
 431         msg.msg_iov = iov;
 432         msg.msg_iovlen = 1;
 433
 434         do {
 435                 ret = sendmsg(sock, &msg, 0);
 436         } while (ret < 0 && errno == EINTR);
 437         if (ret < 0) {
 438                 /*
 439                  * Only warn about EPIPE when quiet mode is deactivated.
 440                  * We consider EPIPE as expected.
 441                  */
 442                 if (errno != EPIPE || !lttng_opt_quiet) {
 443                         PERROR("sendmsg");
 444                 }
 445         }
 446         return ret;
 447 }
 448
 449 /*
 450  * Recv a message accompanied by fd(s) from a unix socket.
 451  *
 452  * Returns the size of received data, or negative error value.
 453  *
 454  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 455  * actually received in nb_fd.
 456  */
 457 LTTNG_HIDDEN
 458 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 459 {
 460         struct iovec iov[1];
 461         ssize_t ret = 0;
 462         struct cmsghdr *cmsg;
 463         size_t sizeof_fds = nb_fd * sizeof(int);
 464
 465 #ifdef __linux__
 466 /* Account for the struct ucred cmsg in the buffer size */
 467 #define LTTNG_SOCK_RECV_FDS_BUF_SIZE CMSG_SPACE(sizeof_fds) + CMSG_SPACE(sizeof(struct ucred))
 468 #else
 469 #define LTTNG_SOCK_RECV_FDS_BUF_SIZE CMSG_SPACE(sizeof_fds)
 470 #endif /* __linux__ */
 471
 472         char recv_buf[LTTNG_SOCK_RECV_FDS_BUF_SIZE];
 473         struct msghdr msg;
 474         char dummy;
 475
 476         memset(&msg, 0, sizeof(msg));
 477
 478         /* Prepare to receive the structures */
 479         iov[0].iov_base = &dummy;
 480         iov[0].iov_len = 1;
 481         msg.msg_iov = iov;
 482         msg.msg_iovlen = 1;
 483
 484         cmsg = (struct cmsghdr *) recv_buf;
 485         cmsg->cmsg_len = CMSG_LEN(sizeof_fds);
 486         cmsg->cmsg_level = SOL_SOCKET;
 487         cmsg->cmsg_type = SCM_RIGHTS;
 488
 489         msg.msg_control = cmsg;
 490         msg.msg_controllen = CMSG_LEN(sizeof(recv_buf));
 491         msg.msg_flags = 0;
 492
 493         do {
 494                 ret = recvmsg(sock, &msg, 0);
 495         } while (ret < 0 && errno == EINTR);
 496         if (ret < 0) {
 497                 PERROR("recvmsg fds");
 498                 goto end;
 499         }
 500
 501         if (ret != 1) {
 502                 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 503                                 ret, 1);
 504                 goto end;
 505         }
 506
 507         if (msg.msg_flags & MSG_CTRUNC) {
 508                 fprintf(stderr, "Error: Control message truncated.\n");
 509                 ret = -1;
 510                 goto end;
 511         }
 512
 513         /*
 514          * If the socket was configured with SO_PASSCRED, the kernel will add a
 515          * control message (cmsg) to the ancillary data of the unix socket. We
 516          * need to expect a cmsg of the SCM_CREDENTIALS as the first control
 517          * message.
 518          */
 519         for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
 520                 if (cmsg->cmsg_level != SOL_SOCKET) {
 521                         fprintf(stderr, "Error: The socket needs to be of type SOL_SOCKET\n");
 522                         ret = -1;
 523                         goto end;
 524                 }
 525                 if (cmsg->cmsg_type == SCM_RIGHTS) {
 526                         /*
 527                          * We found the controle message for file descriptors,
 528                          * now copy the fds to the fds ptr and return success.
 529                          */
 530                         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 531                                 fprintf(stderr, "Error: Received %zu bytes of"
 532                                         "ancillary data for FDs, expected %zu\n",
 533                                         (size_t) cmsg->cmsg_len,
 534                                         (size_t) CMSG_LEN(sizeof_fds));
 535                                 ret = -1;
 536                                 goto end;
 537                         }
 538                         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 539                         ret = sizeof_fds;
 540                         goto end;
 541                 }
 542 #ifdef __linux__
 543                 if (cmsg->cmsg_type == SCM_CREDENTIALS) {
 544                         /*
 545                          * Expect credentials to be sent when expecting fds even
 546                          * if no credential were include in the send(). The
 547                          * kernel adds them...
 548                          */
 549                         ret = -1;
 550                 }
 551 #endif /* __linux__ */
 552         }
 553 end:
 554         return ret;
 555 }
 556
 557 /*
 558  * Send a message with credentials over a unix socket.
 559  *
 560  * Returns the size of data sent, or negative error value.
 561  */
 562 LTTNG_HIDDEN
 563 ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
 564 {
 565         struct msghdr msg;
 566         struct iovec iov[1];
 567         ssize_t ret = -1;
 568 #ifdef __linux__
 569         struct cmsghdr *cmptr;
 570         size_t sizeof_cred = sizeof(lttng_sock_cred);
 571         char anc_buf[CMSG_SPACE(sizeof_cred)];
 572         lttng_sock_cred *creds;
 573
 574         memset(anc_buf, 0, CMSG_SPACE(sizeof_cred) * sizeof(char));
 575 #endif /* __linux__ */
 576
 577         memset(&msg, 0, sizeof(msg));
 578
 579         iov[0].iov_base = buf;
 580         iov[0].iov_len = len;
 581         msg.msg_iov = iov;
 582         msg.msg_iovlen = 1;
 583
 584 #ifdef __linux__
 585         msg.msg_control = (caddr_t) anc_buf;
 586         msg.msg_controllen = CMSG_LEN(sizeof_cred);
 587
 588         cmptr = CMSG_FIRSTHDR(&msg);
 589         if (!cmptr) {
 590                 return -1;
 591         }
 592         cmptr->cmsg_level = SOL_SOCKET;
 593         cmptr->cmsg_type = LTTNG_SOCK_CREDS;
 594         cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
 595
 596         creds = (lttng_sock_cred*) CMSG_DATA(cmptr);
 597
 598         LTTNG_SOCK_SET_UID_CRED(creds, geteuid());
 599         LTTNG_SOCK_SET_GID_CRED(creds, getegid());
 600         LTTNG_SOCK_SET_PID_CRED(creds, getpid());
 601 #endif /* __linux__ */
 602
 603         do {
 604                 ret = sendmsg(sock, &msg, 0);
 605         } while (ret < 0 && errno == EINTR);
 606         if (ret < 0) {
 607                 /*
 608                  * Only warn about EPIPE when quiet mode is deactivated.
 609                  * We consider EPIPE as expected.
 610                  */
 611                 if (errno != EPIPE || !lttng_opt_quiet) {
 612                         PERROR("sendmsg");
 613                 }
 614         }
 615         return ret;
 616 }
 617
 618 /*
 619  * Recv a message accompanied with credentials from a unix socket.
 620  *
 621  * Returns the size of received data, or negative error value.
 622  */
 623 LTTNG_HIDDEN
 624 ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
 625                 lttng_sock_cred *creds)
 626 {
 627         struct msghdr msg;
 628         struct iovec iov[1];
 629         ssize_t ret;
 630         size_t len_last;
 631 #ifdef __linux__
 632         struct cmsghdr *cmptr;
 633         size_t sizeof_cred = sizeof(lttng_sock_cred);
 634         char anc_buf[CMSG_SPACE(sizeof_cred)];
 635 #endif  /* __linux__ */
 636
 637         memset(&msg, 0, sizeof(msg));
 638
 639         /* Not allowed */
 640         if (creds == NULL) {
 641                 ret = -1;
 642                 goto end;
 643         }
 644
 645         /* Prepare to receive the structures */
 646         iov[0].iov_base = buf;
 647         iov[0].iov_len = len;
 648         msg.msg_iov = iov;
 649         msg.msg_iovlen = 1;
 650
 651 #ifdef __linux__
 652         msg.msg_control = anc_buf;
 653         msg.msg_controllen = sizeof(anc_buf);
 654 #endif /* __linux__ */
 655
 656         do {
 657                 len_last = iov[0].iov_len;
 658                 ret = recvmsg(sock, &msg, 0);
 659                 if (ret > 0) {
 660                         iov[0].iov_base += ret;
 661                         iov[0].iov_len -= ret;
 662                         assert(ret <= len_last);
 663                 }
 664         } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
 665         if (ret < 0) {
 666                 PERROR("recvmsg fds");
 667                 goto end;
 668         } else if (ret > 0) {
 669                 ret = len;
 670         }
 671         /* Else ret = 0 meaning an orderly shutdown. */
 672
 673 #ifdef __linux__
 674         if (msg.msg_flags & MSG_CTRUNC) {
 675                 fprintf(stderr, "Error: Control message truncated.\n");
 676                 ret = -1;
 677                 goto end;
 678         }
 679
 680         cmptr = CMSG_FIRSTHDR(&msg);
 681         if (cmptr == NULL) {
 682                 fprintf(stderr, "Error: Invalid control message header\n");
 683                 ret = -1;
 684                 goto end;
 685         }
 686
 687         if (cmptr->cmsg_level != SOL_SOCKET ||
 688                         cmptr->cmsg_type != LTTNG_SOCK_CREDS) {
 689                 fprintf(stderr, "Didn't received any credentials\n");
 690                 ret = -1;
 691                 goto end;
 692         }
 693
 694         if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
 695                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 696                                 (size_t) cmptr->cmsg_len, (size_t) CMSG_LEN(sizeof_cred));
 697                 ret = -1;
 698                 goto end;
 699         }
 700
 701         memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
 702 #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__))
 703         {
 704                 int peer_ret;
 705
 706                 peer_ret = getpeereid(sock, &creds->uid, &creds->gid);
 707                 if (peer_ret != 0) {
 708                         return peer_ret;
 709                 }
 710         }
 711 #else
 712 #error "Please implement credential support for your OS."
 713 #endif  /* __linux__ */
 714
 715 end:
 716         return ret;
 717 }
 718
 719 /*
 720  * Set socket option to use credentials passing.
 721  */
 722 #ifdef __linux__
 723 LTTNG_HIDDEN
 724 int lttcomm_setsockopt_creds_unix_sock(int sock)
 725 {
 726         int ret, on = 1;
 727
 728         /* Set socket for credentials retrieval */
 729         ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 730         if (ret < 0) {
 731                 PERROR("setsockopt creds unix sock");
 732         }
 733         return ret;
 734 }
 735 #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__))
 736 LTTNG_HIDDEN
 737 int lttcomm_setsockopt_creds_unix_sock(int sock)
 738 {
 739         return 0;
 740 }
 741 #else
 742 #error "Please implement credential support for your OS."
 743 #endif /* __linux__ */