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