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 <sys/un.h>
  28 #include <unistd.h>
  29 #include <errno.h>
  30
  31 #include <common/defaults.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_FAIL) ] = "Create trace 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_EVENT_EXIST) ] = "Kernel event already exists",
  61         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_SESS_FAIL) ] = "Kernel create session failed",
  62         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_FAIL) ] = "Kernel create channel failed",
  63         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_NOT_FOUND) ] = "Kernel channel not found",
  64         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_DISABLE_FAIL) ] = "Disable kernel channel failed",
  65         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_ENABLE_FAIL) ] = "Enable kernel channel failed",
  66         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONTEXT_FAIL) ] = "Add kernel context failed",
  67         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_ENABLE_FAIL) ] = "Enable kernel event failed",
  68         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DISABLE_FAIL) ] = "Disable kernel event failed",
  69         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_META_FAIL) ] = "Opening metadata failed",
  70         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_START_FAIL) ] = "Starting kernel trace failed",
  71         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STOP_FAIL) ] = "Stoping kernel trace failed",
  72         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONSUMER_FAIL) ] = "Kernel consumer start failed",
  73         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STREAM_FAIL) ] = "Kernel create stream failed",
  74         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_FAIL) ] = "Kernel trace directory creation failed",
  75         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_EXIST) ] = "Kernel trace directory already exist",
  76         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NO_SESSION) ] = "No kernel session found",
  77         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_LIST_FAIL) ] = "Listing kernel events failed",
  78         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_SESS_FAIL) ] = "UST create session failed",
  79         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_FAIL) ] = "UST create channel failed",
  80         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_EXIST) ] = "UST channel already exist",
  81         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_NOT_FOUND) ] = "UST channel not found",
  82         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_DISABLE_FAIL) ] = "Disable UST channel failed",
  83         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_ENABLE_FAIL) ] = "Enable UST channel failed",
  84         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_FAIL) ] = "Add UST context failed",
  85         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_ENABLE_FAIL) ] = "Enable UST event failed",
  86         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DISABLE_FAIL) ] = "Disable UST event failed",
  87         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_META_FAIL) ] = "Opening metadata failed",
  88         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_START_FAIL) ] = "Starting UST trace failed",
  89         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STOP_FAIL) ] = "Stoping UST trace failed",
  90         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER64_FAIL) ] = "64-bit UST consumer start failed",
  91         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER32_FAIL) ] = "32-bit UST consumer start failed",
  92         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STREAM_FAIL) ] = "UST create stream failed",
  93         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_FAIL) ] = "UST trace directory creation failed",
  94         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_EXIST) ] = "UST trace directory already exist",
  95         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_NO_SESSION) ] = "No UST session found",
  96         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_LIST_FAIL) ] = "Listing UST events failed",
  97         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_EXIST) ] = "UST event already exist",
  98         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_NOT_FOUND)] = "UST event not found",
  99         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_EXIST)] = "UST context already exist",
 100         [ LTTCOMM_ERR_INDEX(CONSUMERD_COMMAND_SOCK_READY) ] = "consumerd command socket ready",
 101         [ LTTCOMM_ERR_INDEX(CONSUMERD_SUCCESS_RECV_FD) ] = "consumerd success on receiving fds",
 102         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_FD) ] = "consumerd error on receiving fds",
 103         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_CMD) ] = "consumerd error on receiving command",
 104         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_ERROR) ] = "consumerd error in polling thread",
 105         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_NVAL) ] = "consumerd polling on closed fd",
 106         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_HUP) ] = "consumerd all fd hung up",
 107         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_SUCCESS) ] = "consumerd exiting normally",
 108         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_FAILURE) ] = "consumerd exiting on error",
 109         [ LTTCOMM_ERR_INDEX(CONSUMERD_OUTFD_ERROR) ] = "consumerd error opening the tracefile",
 110         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EBADF) ] = "consumerd splice EBADF",
 111         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EINVAL) ] = "consumerd splice EINVAL",
 112         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ENOMEM) ] = "consumerd splice ENOMEM",
 113         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ESPIPE) ] = "consumerd splice ESPIPE",
 114         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
 115 };
 116
 117 /*
 118  * Return ptr to string representing a human readable error code from the
 119  * lttcomm_return_code enum.
 120  *
 121  * These code MUST be negative in other to treat that as an error value.
 122  */
 123 const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
 124 {
 125         int tmp_code = -code;
 126
 127         if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
 128                 return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
 129         }
 130
 131         return "Unknown error code";
 132 }
 133
 134 /*
 135  * Connect to unix socket using the path name.
 136  */
 137 int lttcomm_connect_unix_sock(const char *pathname)
 138 {
 139         struct sockaddr_un sun;
 140         int fd;
 141         int ret;
 142
 143         fd = socket(PF_UNIX, SOCK_STREAM, 0);
 144         if (fd < 0) {
 145                 perror("socket");
 146                 ret = fd;
 147                 goto error;
 148         }
 149
 150         memset(&sun, 0, sizeof(sun));
 151         sun.sun_family = AF_UNIX;
 152         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 153         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 154
 155         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 156         if (ret < 0) {
 157                 /*
 158                  * Don't print message on connect error, because connect is used in
 159                  * normal execution to detect if sessiond is alive.
 160                  */
 161                 goto error_connect;
 162         }
 163
 164         return fd;
 165
 166 error_connect:
 167         close(fd);
 168 error:
 169         return ret;
 170 }
 171
 172 /*
 173  * Do an accept(2) on the sock and return the new file descriptor. The socket
 174  * MUST be bind(2) before.
 175  */
 176 int lttcomm_accept_unix_sock(int sock)
 177 {
 178         int new_fd;
 179         struct sockaddr_un sun;
 180         socklen_t len = 0;
 181
 182         /* Blocking call */
 183         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 184         if (new_fd < 0) {
 185                 perror("accept");
 186         }
 187
 188         return new_fd;
 189 }
 190
 191 /*
 192  * Creates a AF_UNIX local socket using pathname bind the socket upon creation
 193  * and return the fd.
 194  */
 195 int lttcomm_create_unix_sock(const char *pathname)
 196 {
 197         struct sockaddr_un sun;
 198         int fd;
 199         int ret = -1;
 200
 201         /* Create server socket */
 202         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 203                 perror("socket");
 204                 goto error;
 205         }
 206
 207         memset(&sun, 0, sizeof(sun));
 208         sun.sun_family = AF_UNIX;
 209         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 210         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 211
 212         /* Unlink the old file if present */
 213         (void) unlink(pathname);
 214         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 215         if (ret < 0) {
 216                 perror("bind");
 217                 goto error;
 218         }
 219
 220         return fd;
 221
 222 error:
 223         return ret;
 224 }
 225
 226 /*
 227  * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
 228  */
 229 int lttcomm_listen_unix_sock(int sock)
 230 {
 231         int ret;
 232
 233         ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
 234         if (ret < 0) {
 235                 perror("listen");
 236         }
 237
 238         return ret;
 239 }
 240
 241 /*
 242  * Receive data of size len in put that data into the buf param. Using recvmsg
 243  * API.
 244  *
 245  * Return the size of received data.
 246  */
 247 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 248 {
 249         struct msghdr msg = { 0 };
 250         struct iovec iov[1];
 251         ssize_t ret = -1;
 252
 253         iov[0].iov_base = buf;
 254         iov[0].iov_len = len;
 255         msg.msg_iov = iov;
 256         msg.msg_iovlen = 1;
 257
 258         ret = recvmsg(sock, &msg, 0);
 259         if (ret < 0) {
 260                 perror("recvmsg");
 261         }
 262
 263         return ret;
 264 }
 265
 266 /*
 267  * Send buf data of size len. Using sendmsg API.
 268  *
 269  * Return the size of sent data.
 270  */
 271 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
 272 {
 273         struct msghdr msg = { 0 };
 274         struct iovec iov[1];
 275         ssize_t ret = -1;
 276
 277         iov[0].iov_base = buf;
 278         iov[0].iov_len = len;
 279         msg.msg_iov = iov;
 280         msg.msg_iovlen = 1;
 281
 282         ret = sendmsg(sock, &msg, 0);
 283         if (ret < 0) {
 284                 perror("sendmsg");
 285         }
 286
 287         return ret;
 288 }
 289
 290 /*
 291  * Shutdown cleanly a unix socket.
 292  */
 293 int lttcomm_close_unix_sock(int sock)
 294 {
 295         int ret;
 296
 297         /* Shutdown receptions and transmissions */
 298         ret = shutdown(sock, SHUT_RDWR);
 299         if (ret < 0) {
 300                 perror("shutdown");
 301         }
 302
 303         return ret;
 304 }
 305
 306 /*
 307  * Send a message accompanied by fd(s) over a unix socket.
 308  *
 309  * Returns the size of data sent, or negative error value.
 310  */
 311 ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 312 {
 313         struct msghdr msg = { 0 };
 314         struct cmsghdr *cmptr;
 315         struct iovec iov[1];
 316         ssize_t ret = -1;
 317         unsigned int sizeof_fds = nb_fd * sizeof(int);
 318         char tmp[CMSG_SPACE(sizeof_fds)];
 319         char dummy = 0;
 320
 321         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 322                 return -EINVAL;
 323
 324         msg.msg_control = (caddr_t)tmp;
 325         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 326
 327         cmptr = CMSG_FIRSTHDR(&msg);
 328         cmptr->cmsg_level = SOL_SOCKET;
 329         cmptr->cmsg_type = SCM_RIGHTS;
 330         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 331         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 332         /* Sum of the length of all control messages in the buffer: */
 333         msg.msg_controllen = cmptr->cmsg_len;
 334
 335         iov[0].iov_base = &dummy;
 336         iov[0].iov_len = 1;
 337         msg.msg_iov = iov;
 338         msg.msg_iovlen = 1;
 339
 340         ret = sendmsg(sock, &msg, 0);
 341         if (ret < 0) {
 342                 perror("sendmsg");
 343         }
 344         return ret;
 345 }
 346
 347 /*
 348  * Recv a message accompanied by fd(s) from a unix socket.
 349  *
 350  * Returns the size of received data, or negative error value.
 351  *
 352  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 353  * actually received in nb_fd.
 354  */
 355 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 356 {
 357         struct iovec iov[1];
 358         ssize_t ret = 0;
 359         struct cmsghdr *cmsg;
 360         size_t sizeof_fds = nb_fd * sizeof(int);
 361         char recv_fd[CMSG_SPACE(sizeof_fds)];
 362         struct msghdr msg = { 0 };
 363         char dummy;
 364
 365         /* Prepare to receive the structures */
 366         iov[0].iov_base = &dummy;
 367         iov[0].iov_len = 1;
 368         msg.msg_iov = iov;
 369         msg.msg_iovlen = 1;
 370         msg.msg_control = recv_fd;
 371         msg.msg_controllen = sizeof(recv_fd);
 372
 373         ret = recvmsg(sock, &msg, 0);
 374         if (ret < 0) {
 375                 perror("recvmsg fds");
 376                 goto end;
 377         }
 378         if (ret != 1) {
 379                 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 380                                 ret, 1);
 381                 goto end;
 382         }
 383         if (msg.msg_flags & MSG_CTRUNC) {
 384                 fprintf(stderr, "Error: Control message truncated.\n");
 385                 ret = -1;
 386                 goto end;
 387         }
 388         cmsg = CMSG_FIRSTHDR(&msg);
 389         if (!cmsg) {
 390                 fprintf(stderr, "Error: Invalid control message header\n");
 391                 ret = -1;
 392                 goto end;
 393         }
 394         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 395                 fprintf(stderr, "Didn't received any fd\n");
 396                 ret = -1;
 397                 goto end;
 398         }
 399         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 400                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 401                                 cmsg->cmsg_len, CMSG_LEN(sizeof_fds));
 402                 ret = -1;
 403                 goto end;
 404         }
 405         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 406         ret = sizeof_fds;
 407 end:
 408         return ret;
 409 }
 410
 411 /*
 412  * Send a message with credentials over a unix socket.
 413  *
 414  * Returns the size of data sent, or negative error value.
 415  */
 416 ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
 417 {
 418         struct msghdr msg = { 0 };
 419         struct cmsghdr *cmptr;
 420         struct iovec iov[1];
 421         ssize_t ret = -1;
 422         struct ucred *creds;
 423         size_t sizeof_cred = sizeof(struct ucred);
 424         char anc_buf[CMSG_SPACE(sizeof_cred)];
 425
 426         iov[0].iov_base = buf;
 427         iov[0].iov_len = len;
 428         msg.msg_iov = iov;
 429         msg.msg_iovlen = 1;
 430
 431         msg.msg_control = (caddr_t) anc_buf;
 432         msg.msg_controllen = CMSG_LEN(sizeof_cred);
 433
 434         cmptr = CMSG_FIRSTHDR(&msg);
 435         cmptr->cmsg_level = SOL_SOCKET;
 436         cmptr->cmsg_type = SCM_CREDENTIALS;
 437         cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
 438
 439         creds = (struct ucred *) CMSG_DATA(cmptr);
 440
 441         creds->uid = geteuid();
 442         creds->gid = getegid();
 443         creds->pid = getpid();
 444
 445         ret = sendmsg(sock, &msg, 0);
 446         if (ret < 0) {
 447                 perror("sendmsg");
 448         }
 449
 450         return ret;
 451 }
 452
 453 /*
 454  * Recv a message accompanied with credentials from a unix socket.
 455  *
 456  * Returns the size of received data, or negative error value.
 457  */
 458 ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
 459                 struct ucred *creds)
 460 {
 461         struct msghdr msg = { 0 };
 462         struct cmsghdr *cmptr;
 463         struct iovec iov[1];
 464         ssize_t ret;
 465         size_t sizeof_cred = sizeof(struct ucred);
 466         char anc_buf[CMSG_SPACE(sizeof_cred)];
 467
 468         /* Not allowed */
 469         if (creds == NULL) {
 470                 ret = -1;
 471                 goto end;
 472         }
 473
 474         /* Prepare to receive the structures */
 475         iov[0].iov_base = buf;
 476         iov[0].iov_len = len;
 477         msg.msg_iov = iov;
 478         msg.msg_iovlen = 1;
 479
 480         msg.msg_control = anc_buf;
 481         msg.msg_controllen = sizeof(anc_buf);
 482
 483         ret = recvmsg(sock, &msg, 0);
 484         if (ret < 0) {
 485                 perror("recvmsg fds");
 486                 goto end;
 487         }
 488
 489         if (msg.msg_flags & MSG_CTRUNC) {
 490                 fprintf(stderr, "Error: Control message truncated.\n");
 491                 ret = -1;
 492                 goto end;
 493         }
 494
 495         cmptr = CMSG_FIRSTHDR(&msg);
 496         if (cmptr == NULL) {
 497                 fprintf(stderr, "Error: Invalid control message header\n");
 498                 ret = -1;
 499                 goto end;
 500         }
 501
 502         if (cmptr->cmsg_level != SOL_SOCKET ||
 503                         cmptr->cmsg_type != SCM_CREDENTIALS) {
 504                 fprintf(stderr, "Didn't received any credentials\n");
 505                 ret = -1;
 506                 goto end;
 507         }
 508
 509         if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
 510                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 511                                 cmptr->cmsg_len, CMSG_LEN(sizeof_cred));
 512                 ret = -1;
 513                 goto end;
 514         }
 515
 516         memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
 517
 518 end:
 519         return ret;
 520 }
 521
 522 /*
 523  * Set socket option to use credentials passing.
 524  */
 525 int lttcomm_setsockopt_creds_unix_sock(int sock)
 526 {
 527         int ret, on = 1;
 528
 529         /* Set socket for credentials retrieval */
 530         ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 531         if (ret < 0) {
 532                 perror("setsockopt creds unix sock");
 533         }
 534
 535         return ret;
 536 }