src/common/sessiond-comm/sessiond-comm.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 it
   6  * under the terms of the GNU General Public License as published by the Free
   7  * Software Foundation; only version 2 of the License.
   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 with
  15  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  16  * Place - Suite 330, Boston, MA  02111-1307, USA.
  17  */
  18
  19 #define _GNU_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/defaults.h>
  31 #include <common/error.h>
  32
  33 #include "sessiond-comm.h"
  34
  35 /*
  36  * Human readable error message.
  37  */
  38 static const char *lttcomm_readable_code[] = {
  39         [ LTTCOMM_ERR_INDEX(LTTCOMM_OK) ] = "Success",
  40         [ LTTCOMM_ERR_INDEX(LTTCOMM_ERR) ] = "Unknown error",
  41         [ LTTCOMM_ERR_INDEX(LTTCOMM_UND) ] = "Undefined command",
  42         [ LTTCOMM_ERR_INDEX(LTTCOMM_NOT_IMPLEMENTED) ] = "Not implemented",
  43         [ LTTCOMM_ERR_INDEX(LTTCOMM_UNKNOWN_DOMAIN) ] = "Unknown tracing domain",
  44         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_SESSION) ] = "No session found",
  45         [ LTTCOMM_ERR_INDEX(LTTCOMM_LIST_FAIL) ] = "Unable to list traceable apps",
  46         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_APPS) ] = "No traceable apps found",
  47         [ LTTCOMM_ERR_INDEX(LTTCOMM_SESS_NOT_FOUND) ] = "Session name not found",
  48         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACE) ] = "No trace found",
  49         [ LTTCOMM_ERR_INDEX(LTTCOMM_FATAL) ] = "Fatal error of the session daemon",
  50         [ LTTCOMM_ERR_INDEX(LTTCOMM_CREATE_DIR_FAIL) ] = "Create directory failed",
  51         [ LTTCOMM_ERR_INDEX(LTTCOMM_START_FAIL) ] = "Start trace failed",
  52         [ LTTCOMM_ERR_INDEX(LTTCOMM_STOP_FAIL) ] = "Stop trace failed",
  53         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACEABLE) ] = "App is not traceable",
  54         [ LTTCOMM_ERR_INDEX(LTTCOMM_SELECT_SESS) ] = "A session MUST be selected",
  55         [ LTTCOMM_ERR_INDEX(LTTCOMM_EXIST_SESS) ] = "Session name already exist",
  56         [ LTTCOMM_ERR_INDEX(LTTCOMM_CONNECT_FAIL) ] = "Unable to connect to Unix socket",
  57         [ LTTCOMM_ERR_INDEX(LTTCOMM_APP_NOT_FOUND) ] = "Application not found",
  58         [ LTTCOMM_ERR_INDEX(LTTCOMM_EPERM) ] = "Permission denied",
  59         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NA) ] = "Kernel tracer not available",
  60         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_VERSION) ] = "Kernel tracer version is not compatible",
  61         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_EVENT_EXIST) ] = "Kernel event already exists",
  62         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_SESS_FAIL) ] = "Kernel create session failed",
  63         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_FAIL) ] = "Kernel create channel failed",
  64         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_NOT_FOUND) ] = "Kernel channel not found",
  65         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_DISABLE_FAIL) ] = "Disable kernel channel failed",
  66         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_ENABLE_FAIL) ] = "Enable kernel channel failed",
  67         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONTEXT_FAIL) ] = "Add kernel context failed",
  68         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_ENABLE_FAIL) ] = "Enable kernel event failed",
  69         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DISABLE_FAIL) ] = "Disable kernel event failed",
  70         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_META_FAIL) ] = "Opening metadata failed",
  71         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_START_FAIL) ] = "Starting kernel trace failed",
  72         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STOP_FAIL) ] = "Stoping kernel trace failed",
  73         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONSUMER_FAIL) ] = "Kernel consumer start failed",
  74         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STREAM_FAIL) ] = "Kernel create stream failed",
  75         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_FAIL) ] = "Kernel trace directory creation failed",
  76         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_EXIST) ] = "Kernel trace directory already exist",
  77         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NO_SESSION) ] = "No kernel session found",
  78         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_LIST_FAIL) ] = "Listing kernel events failed",
  79         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CALIBRATE_FAIL) ] = "UST calibration failed",
  80         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_VERSION) ] = "UST tracer version is not compatible",
  81         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_SESS_FAIL) ] = "UST create session failed",
  82         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_FAIL) ] = "UST create channel failed",
  83         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_EXIST) ] = "UST channel already exist",
  84         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_NOT_FOUND) ] = "UST channel not found",
  85         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_DISABLE_FAIL) ] = "Disable UST channel failed",
  86         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_ENABLE_FAIL) ] = "Enable UST channel failed",
  87         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_FAIL) ] = "Add UST context failed",
  88         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_ENABLE_FAIL) ] = "Enable UST event failed",
  89         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DISABLE_FAIL) ] = "Disable UST event failed",
  90         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_META_FAIL) ] = "Opening metadata failed",
  91         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_START_FAIL) ] = "Starting UST trace failed",
  92         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STOP_FAIL) ] = "Stoping UST trace failed",
  93         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER64_FAIL) ] = "64-bit UST consumer start failed",
  94         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER32_FAIL) ] = "32-bit UST consumer start failed",
  95         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STREAM_FAIL) ] = "UST create stream failed",
  96         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_FAIL) ] = "UST trace directory creation failed",
  97         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_EXIST) ] = "UST trace directory already exist",
  98         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_NO_SESSION) ] = "No UST session found",
  99         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_LIST_FAIL) ] = "Listing UST events failed",
 100         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_EXIST) ] = "UST event already exist",
 101         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_NOT_FOUND)] = "UST event not found",
 102         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_EXIST)] = "UST context already exist",
 103         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_INVAL)] = "UST invalid context",
 104         [ LTTCOMM_ERR_INDEX(LTTCOMM_NEED_ROOT_SESSIOND) ] = "Tracing the kernel requires a root lttng-sessiond daemon and \"tracing\" group user membership",
 105         [ LTTCOMM_ERR_INDEX(LTTCOMM_TRACE_ALREADY_STARTED) ] = "Tracing already started",
 106         [ LTTCOMM_ERR_INDEX(LTTCOMM_TRACE_ALREADY_STOPPED) ] = "Tracing already stopped",
 107
 108         [ LTTCOMM_ERR_INDEX(CONSUMERD_COMMAND_SOCK_READY) ] = "consumerd command socket ready",
 109         [ LTTCOMM_ERR_INDEX(CONSUMERD_SUCCESS_RECV_FD) ] = "consumerd success on receiving fds",
 110         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_FD) ] = "consumerd error on receiving fds",
 111         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_CMD) ] = "consumerd error on receiving command",
 112         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_ERROR) ] = "consumerd error in polling thread",
 113         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_NVAL) ] = "consumerd polling on closed fd",
 114         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_HUP) ] = "consumerd all fd hung up",
 115         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_SUCCESS) ] = "consumerd exiting normally",
 116         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_FAILURE) ] = "consumerd exiting on error",
 117         [ LTTCOMM_ERR_INDEX(CONSUMERD_OUTFD_ERROR) ] = "consumerd error opening the tracefile",
 118         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EBADF) ] = "consumerd splice EBADF",
 119         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EINVAL) ] = "consumerd splice EINVAL",
 120         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ENOMEM) ] = "consumerd splice ENOMEM",
 121         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ESPIPE) ] = "consumerd splice ESPIPE",
 122         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
 123 };
 124
 125 /*
 126  * Return ptr to string representing a human readable error code from the
 127  * lttcomm_return_code enum.
 128  *
 129  * These code MUST be negative in other to treat that as an error value.
 130  */
 131 const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
 132 {
 133         int tmp_code = -code;
 134
 135         if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
 136                 return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
 137         }
 138
 139         return "Unknown error code";
 140 }
 141
 142 /*
 143  * Connect to unix socket using the path name.
 144  */
 145 int lttcomm_connect_unix_sock(const char *pathname)
 146 {
 147         struct sockaddr_un sun;
 148         int fd, ret, closeret;
 149
 150         fd = socket(PF_UNIX, SOCK_STREAM, 0);
 151         if (fd < 0) {
 152                 PERROR("socket");
 153                 ret = fd;
 154                 goto error;
 155         }
 156
 157         memset(&sun, 0, sizeof(sun));
 158         sun.sun_family = AF_UNIX;
 159         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 160         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 161
 162         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 163         if (ret < 0) {
 164                 /*
 165                  * Don't print message on connect error, because connect is used in
 166                  * normal execution to detect if sessiond is alive.
 167                  */
 168                 goto error_connect;
 169         }
 170
 171         return fd;
 172
 173 error_connect:
 174         closeret = close(fd);
 175         if (closeret) {
 176                 PERROR("close");
 177         }
 178 error:
 179         return ret;
 180 }
 181
 182 /*
 183  * Do an accept(2) on the sock and return the new file descriptor. The socket
 184  * MUST be bind(2) before.
 185  */
 186 int lttcomm_accept_unix_sock(int sock)
 187 {
 188         int new_fd;
 189         struct sockaddr_un sun;
 190         socklen_t len = 0;
 191
 192         /* Blocking call */
 193         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 194         if (new_fd < 0) {
 195                 PERROR("accept");
 196         }
 197
 198         return new_fd;
 199 }
 200
 201 /*
 202  * Creates a AF_UNIX local socket using pathname bind the socket upon creation
 203  * and return the fd.
 204  */
 205 int lttcomm_create_unix_sock(const char *pathname)
 206 {
 207         struct sockaddr_un sun;
 208         int fd;
 209         int ret = -1;
 210
 211         /* Create server socket */
 212         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 213                 PERROR("socket");
 214                 goto error;
 215         }
 216
 217         memset(&sun, 0, sizeof(sun));
 218         sun.sun_family = AF_UNIX;
 219         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 220         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 221
 222         /* Unlink the old file if present */
 223         (void) unlink(pathname);
 224         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 225         if (ret < 0) {
 226                 PERROR("bind");
 227                 goto error;
 228         }
 229
 230         return fd;
 231
 232 error:
 233         return ret;
 234 }
 235
 236 /*
 237  * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
 238  */
 239 int lttcomm_listen_unix_sock(int sock)
 240 {
 241         int ret;
 242
 243         ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
 244         if (ret < 0) {
 245                 PERROR("listen");
 246         }
 247
 248         return ret;
 249 }
 250
 251 /*
 252  * Receive data of size len in put that data into the buf param. Using recvmsg
 253  * API.
 254  *
 255  * Return the size of received data.
 256  */
 257 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 258 {
 259         struct msghdr msg;
 260         struct iovec iov[1];
 261         ssize_t ret = -1;
 262
 263         memset(&msg, 0, sizeof(msg));
 264
 265         iov[0].iov_base = buf;
 266         iov[0].iov_len = len;
 267         msg.msg_iov = iov;
 268         msg.msg_iovlen = 1;
 269
 270         do {
 271                 ret = recvmsg(sock, &msg, MSG_WAITALL);
 272         } while (ret < 0 && errno == EINTR);
 273         if (ret < 0) {
 274                 PERROR("recvmsg");
 275         }
 276
 277         return ret;
 278 }
 279
 280 /*
 281  * Send buf data of size len. Using sendmsg API.
 282  *
 283  * Return the size of sent data.
 284  */
 285 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
 286 {
 287         struct msghdr msg;
 288         struct iovec iov[1];
 289         ssize_t ret = -1;
 290
 291         memset(&msg, 0, sizeof(msg));
 292
 293         iov[0].iov_base = buf;
 294         iov[0].iov_len = len;
 295         msg.msg_iov = iov;
 296         msg.msg_iovlen = 1;
 297
 298         ret = sendmsg(sock, &msg, 0);
 299         if (ret < 0) {
 300                 /*
 301                  * Only warn about EPIPE when quiet mode is deactivated.
 302                  * We consider EPIPE as expected.
 303                  */
 304                 if (errno != EPIPE || !lttng_opt_quiet) {
 305                         PERROR("sendmsg");
 306                 }
 307         }
 308
 309         return ret;
 310 }
 311
 312 /*
 313  * Shutdown cleanly a unix socket.
 314  */
 315 int lttcomm_close_unix_sock(int sock)
 316 {
 317         int ret, closeret;
 318
 319         /* Shutdown receptions and transmissions */
 320         ret = shutdown(sock, SHUT_RDWR);
 321         if (ret < 0) {
 322                 PERROR("shutdown");
 323         }
 324
 325         closeret = close(sock);
 326         if (closeret) {
 327                 PERROR("close");
 328         }
 329
 330         return ret;
 331 }
 332
 333 /*
 334  * Send a message accompanied by fd(s) over a unix socket.
 335  *
 336  * Returns the size of data sent, or negative error value.
 337  */
 338 ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 339 {
 340         struct msghdr msg;
 341         struct cmsghdr *cmptr;
 342         struct iovec iov[1];
 343         ssize_t ret = -1;
 344         unsigned int sizeof_fds = nb_fd * sizeof(int);
 345         char tmp[CMSG_SPACE(sizeof_fds)];
 346         char dummy = 0;
 347
 348         memset(&msg, 0, sizeof(msg));
 349
 350         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 351                 return -EINVAL;
 352
 353         msg.msg_control = (caddr_t)tmp;
 354         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 355
 356         cmptr = CMSG_FIRSTHDR(&msg);
 357         cmptr->cmsg_level = SOL_SOCKET;
 358         cmptr->cmsg_type = SCM_RIGHTS;
 359         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 360         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 361         /* Sum of the length of all control messages in the buffer: */
 362         msg.msg_controllen = cmptr->cmsg_len;
 363
 364         iov[0].iov_base = &dummy;
 365         iov[0].iov_len = 1;
 366         msg.msg_iov = iov;
 367         msg.msg_iovlen = 1;
 368
 369         ret = sendmsg(sock, &msg, 0);
 370         if (ret < 0) {
 371                 /*
 372                  * Only warn about EPIPE when quiet mode is deactivated.
 373                  * We consider EPIPE as expected.
 374                  */
 375                 if (errno != EPIPE || !lttng_opt_quiet) {
 376                         PERROR("sendmsg");
 377                 }
 378         }
 379         return ret;
 380 }
 381
 382 /*
 383  * Recv a message accompanied by fd(s) from a unix socket.
 384  *
 385  * Returns the size of received data, or negative error value.
 386  *
 387  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 388  * actually received in nb_fd.
 389  */
 390 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 391 {
 392         struct iovec iov[1];
 393         ssize_t ret = 0;
 394         struct cmsghdr *cmsg;
 395         size_t sizeof_fds = nb_fd * sizeof(int);
 396         char recv_fd[CMSG_SPACE(sizeof_fds)];
 397         struct msghdr msg;
 398         char dummy;
 399
 400         memset(&msg, 0, sizeof(msg));
 401
 402         /* Prepare to receive the structures */
 403         iov[0].iov_base = &dummy;
 404         iov[0].iov_len = 1;
 405         msg.msg_iov = iov;
 406         msg.msg_iovlen = 1;
 407         msg.msg_control = recv_fd;
 408         msg.msg_controllen = sizeof(recv_fd);
 409
 410         do {
 411                 ret = recvmsg(sock, &msg, 0);
 412         } while (ret < 0 && errno == EINTR);
 413         if (ret < 0) {
 414                 PERROR("recvmsg fds");
 415                 goto end;
 416         }
 417         if (ret != 1) {
 418                 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 419                                 ret, 1);
 420                 goto end;
 421         }
 422         if (msg.msg_flags & MSG_CTRUNC) {
 423                 fprintf(stderr, "Error: Control message truncated.\n");
 424                 ret = -1;
 425                 goto end;
 426         }
 427         cmsg = CMSG_FIRSTHDR(&msg);
 428         if (!cmsg) {
 429                 fprintf(stderr, "Error: Invalid control message header\n");
 430                 ret = -1;
 431                 goto end;
 432         }
 433         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 434                 fprintf(stderr, "Didn't received any fd\n");
 435                 ret = -1;
 436                 goto end;
 437         }
 438         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 439                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 440                                 (size_t) cmsg->cmsg_len, (size_t) CMSG_LEN(sizeof_fds));
 441                 ret = -1;
 442                 goto end;
 443         }
 444         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 445         ret = sizeof_fds;
 446 end:
 447         return ret;
 448 }
 449
 450 /*
 451  * Send a message with credentials over a unix socket.
 452  *
 453  * Returns the size of data sent, or negative error value.
 454  */
 455 ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
 456 {
 457         struct msghdr msg;
 458         struct iovec iov[1];
 459         ssize_t ret = -1;
 460 #ifdef __linux__
 461         struct cmsghdr *cmptr;
 462         size_t sizeof_cred = sizeof(lttng_sock_cred);
 463         char anc_buf[CMSG_SPACE(sizeof_cred)];
 464         lttng_sock_cred *creds;
 465 #endif /* __linux__ */
 466
 467         memset(&msg, 0, sizeof(msg));
 468
 469         iov[0].iov_base = buf;
 470         iov[0].iov_len = len;
 471         msg.msg_iov = iov;
 472         msg.msg_iovlen = 1;
 473
 474 #ifdef __linux__
 475         msg.msg_control = (caddr_t) anc_buf;
 476         msg.msg_controllen = CMSG_LEN(sizeof_cred);
 477
 478         cmptr = CMSG_FIRSTHDR(&msg);
 479         cmptr->cmsg_level = SOL_SOCKET;
 480         cmptr->cmsg_type = LTTNG_SOCK_CREDS;
 481         cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
 482
 483         creds = (lttng_sock_cred*) CMSG_DATA(cmptr);
 484
 485         LTTNG_SOCK_SET_UID_CRED(creds, geteuid());
 486         LTTNG_SOCK_SET_GID_CRED(creds, getegid());
 487         LTTNG_SOCK_SET_PID_CRED(creds, getpid());
 488 #endif /* __linux__ */
 489
 490         ret = sendmsg(sock, &msg, 0);
 491         if (ret < 0) {
 492                 /*
 493                  * Only warn about EPIPE when quiet mode is deactivated.
 494                  * We consider EPIPE as expected.
 495                  */
 496                 if (errno != EPIPE || !lttng_opt_quiet) {
 497                         PERROR("sendmsg");
 498                 }
 499         }
 500         return ret;
 501 }
 502
 503 /*
 504  * Recv a message accompanied with credentials from a unix socket.
 505  *
 506  * Returns the size of received data, or negative error value.
 507  */
 508 ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
 509                 lttng_sock_cred *creds)
 510 {
 511         struct msghdr msg;
 512         struct iovec iov[1];
 513         ssize_t ret;
 514 #ifdef __linux__
 515         struct cmsghdr *cmptr;
 516         size_t sizeof_cred = sizeof(lttng_sock_cred);
 517         char anc_buf[CMSG_SPACE(sizeof_cred)];
 518 #endif  /* __linux__ */
 519
 520         memset(&msg, 0, sizeof(msg));
 521
 522         /* Not allowed */
 523         if (creds == NULL) {
 524                 ret = -1;
 525                 goto end;
 526         }
 527
 528         /* Prepare to receive the structures */
 529         iov[0].iov_base = buf;
 530         iov[0].iov_len = len;
 531         msg.msg_iov = iov;
 532         msg.msg_iovlen = 1;
 533
 534 #ifdef __linux__
 535         msg.msg_control = anc_buf;
 536         msg.msg_controllen = sizeof(anc_buf);
 537 #endif /* __linux__ */
 538
 539         do {
 540                 ret = recvmsg(sock, &msg, 0);
 541         } while (ret < 0 && errno == EINTR);
 542         if (ret < 0) {
 543                 PERROR("recvmsg fds");
 544                 goto end;
 545         }
 546
 547 #ifdef __linux__
 548         if (msg.msg_flags & MSG_CTRUNC) {
 549                 fprintf(stderr, "Error: Control message truncated.\n");
 550                 ret = -1;
 551                 goto end;
 552         }
 553
 554         cmptr = CMSG_FIRSTHDR(&msg);
 555         if (cmptr == NULL) {
 556                 fprintf(stderr, "Error: Invalid control message header\n");
 557                 ret = -1;
 558                 goto end;
 559         }
 560
 561         if (cmptr->cmsg_level != SOL_SOCKET ||
 562                         cmptr->cmsg_type != LTTNG_SOCK_CREDS) {
 563                 fprintf(stderr, "Didn't received any credentials\n");
 564                 ret = -1;
 565                 goto end;
 566         }
 567
 568         if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
 569                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 570                                 (size_t) cmptr->cmsg_len, (size_t) CMSG_LEN(sizeof_cred));
 571                 ret = -1;
 572                 goto end;
 573         }
 574
 575         memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
 576 #elif defined(__FreeBSD__)
 577         {
 578                 int peer_ret;
 579
 580                 peer_ret = getpeereid(sock, &creds->uid, &creds->gid);
 581                 if (peer_ret != 0) {
 582                         return peer_ret;
 583                 }
 584         }
 585 #else
 586 #error "Please implement credential support for your OS."
 587 #endif  /* __linux__ */
 588
 589 end:
 590         return ret;
 591 }
 592
 593 /*
 594  * Set socket option to use credentials passing.
 595  */
 596 #ifdef __linux__
 597 int lttcomm_setsockopt_creds_unix_sock(int sock)
 598 {
 599         int ret, on = 1;
 600
 601         /* Set socket for credentials retrieval */
 602         ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 603         if (ret < 0) {
 604                 PERROR("setsockopt creds unix sock");
 605         }
 606         return ret;
 607 }
 608 #elif defined(__FreeBSD__)
 609 int lttcomm_setsockopt_creds_unix_sock(int sock)
 610 {
 611         return 0;
 612 }
 613 #else
 614 #error "Please implement credential support for your OS."
 615 #endif /* __linux__ */