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         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_EVENT_ENOSYS) ] = "Kernel event type not supported",
 109
 110         [ LTTCOMM_ERR_INDEX(CONSUMERD_COMMAND_SOCK_READY) ] = "consumerd command socket ready",
 111         [ LTTCOMM_ERR_INDEX(CONSUMERD_SUCCESS_RECV_FD) ] = "consumerd success on receiving fds",
 112         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_FD) ] = "consumerd error on receiving fds",
 113         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_CMD) ] = "consumerd error on receiving command",
 114         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_ERROR) ] = "consumerd error in polling thread",
 115         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_NVAL) ] = "consumerd polling on closed fd",
 116         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_HUP) ] = "consumerd all fd hung up",
 117         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_SUCCESS) ] = "consumerd exiting normally",
 118         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_FAILURE) ] = "consumerd exiting on error",
 119         [ LTTCOMM_ERR_INDEX(CONSUMERD_OUTFD_ERROR) ] = "consumerd error opening the tracefile",
 120         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EBADF) ] = "consumerd splice EBADF",
 121         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EINVAL) ] = "consumerd splice EINVAL",
 122         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ENOMEM) ] = "consumerd splice ENOMEM",
 123         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ESPIPE) ] = "consumerd splice ESPIPE",
 124         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
 125         [ LTTCOMM_ERR_INDEX(LTTCOMM_INVALID) ] = "Invalid parameter",
 126         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_USTCONSUMERD) ] = "No UST consumer detected",
 127         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_KERNCONSUMERD) ] = "No kernel consumer detected",
 128         [ LTTCOMM_ERR_INDEX(LTTCOMM_EVENT_EXIST_LOGLEVEL) ] = "Event already enabled with different loglevel",
 129 };
 130
 131 /*
 132  * Return ptr to string representing a human readable error code from the
 133  * lttcomm_return_code enum.
 134  *
 135  * These code MUST be negative in other to treat that as an error value.
 136  */
 137 const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
 138 {
 139         int tmp_code = -code;
 140
 141         if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
 142                 return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
 143         }
 144
 145         return "Unknown error code";
 146 }
 147
 148 /*
 149  * Connect to unix socket using the path name.
 150  */
 151 int lttcomm_connect_unix_sock(const char *pathname)
 152 {
 153         struct sockaddr_un sun;
 154         int fd, ret, closeret;
 155
 156         fd = socket(PF_UNIX, SOCK_STREAM, 0);
 157         if (fd < 0) {
 158                 PERROR("socket");
 159                 ret = fd;
 160                 goto error;
 161         }
 162
 163         memset(&sun, 0, sizeof(sun));
 164         sun.sun_family = AF_UNIX;
 165         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 166         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 167
 168         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 169         if (ret < 0) {
 170                 /*
 171                  * Don't print message on connect error, because connect is used in
 172                  * normal execution to detect if sessiond is alive.
 173                  */
 174                 goto error_connect;
 175         }
 176
 177         return fd;
 178
 179 error_connect:
 180         closeret = close(fd);
 181         if (closeret) {
 182                 PERROR("close");
 183         }
 184 error:
 185         return ret;
 186 }
 187
 188 /*
 189  * Do an accept(2) on the sock and return the new file descriptor. The socket
 190  * MUST be bind(2) before.
 191  */
 192 int lttcomm_accept_unix_sock(int sock)
 193 {
 194         int new_fd;
 195         struct sockaddr_un sun;
 196         socklen_t len = 0;
 197
 198         /* Blocking call */
 199         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 200         if (new_fd < 0) {
 201                 PERROR("accept");
 202         }
 203
 204         return new_fd;
 205 }
 206
 207 /*
 208  * Creates a AF_UNIX local socket using pathname bind the socket upon creation
 209  * and return the fd.
 210  */
 211 int lttcomm_create_unix_sock(const char *pathname)
 212 {
 213         struct sockaddr_un sun;
 214         int fd;
 215         int ret = -1;
 216
 217         /* Create server socket */
 218         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 219                 PERROR("socket");
 220                 goto error;
 221         }
 222
 223         memset(&sun, 0, sizeof(sun));
 224         sun.sun_family = AF_UNIX;
 225         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 226         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 227
 228         /* Unlink the old file if present */
 229         (void) unlink(pathname);
 230         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 231         if (ret < 0) {
 232                 PERROR("bind");
 233                 goto error;
 234         }
 235
 236         return fd;
 237
 238 error:
 239         return ret;
 240 }
 241
 242 /*
 243  * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
 244  */
 245 int lttcomm_listen_unix_sock(int sock)
 246 {
 247         int ret;
 248
 249         ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
 250         if (ret < 0) {
 251                 PERROR("listen");
 252         }
 253
 254         return ret;
 255 }
 256
 257 /*
 258  * Receive data of size len in put that data into the buf param. Using recvmsg
 259  * API.
 260  *
 261  * Return the size of received data.
 262  */
 263 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 264 {
 265         struct msghdr msg;
 266         struct iovec iov[1];
 267         ssize_t ret = -1;
 268
 269         memset(&msg, 0, sizeof(msg));
 270
 271         iov[0].iov_base = buf;
 272         iov[0].iov_len = len;
 273         msg.msg_iov = iov;
 274         msg.msg_iovlen = 1;
 275
 276         do {
 277                 ret = recvmsg(sock, &msg, MSG_WAITALL);
 278         } while (ret < 0 && errno == EINTR);
 279         if (ret < 0) {
 280                 PERROR("recvmsg");
 281         }
 282
 283         return ret;
 284 }
 285
 286 /*
 287  * Send buf data of size len. Using sendmsg API.
 288  *
 289  * Return the size of sent data.
 290  */
 291 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
 292 {
 293         struct msghdr msg;
 294         struct iovec iov[1];
 295         ssize_t ret = -1;
 296
 297         memset(&msg, 0, sizeof(msg));
 298
 299         iov[0].iov_base = buf;
 300         iov[0].iov_len = len;
 301         msg.msg_iov = iov;
 302         msg.msg_iovlen = 1;
 303
 304         ret = sendmsg(sock, &msg, 0);
 305         if (ret < 0) {
 306                 /*
 307                  * Only warn about EPIPE when quiet mode is deactivated.
 308                  * We consider EPIPE as expected.
 309                  */
 310                 if (errno != EPIPE || !lttng_opt_quiet) {
 311                         PERROR("sendmsg");
 312                 }
 313         }
 314
 315         return ret;
 316 }
 317
 318 /*
 319  * Shutdown cleanly a unix socket.
 320  */
 321 int lttcomm_close_unix_sock(int sock)
 322 {
 323         int ret, closeret;
 324
 325         /* Shutdown receptions and transmissions */
 326         ret = shutdown(sock, SHUT_RDWR);
 327         if (ret < 0) {
 328                 PERROR("shutdown");
 329         }
 330
 331         closeret = close(sock);
 332         if (closeret) {
 333                 PERROR("close");
 334         }
 335
 336         return ret;
 337 }
 338
 339 /*
 340  * Send a message accompanied by fd(s) over a unix socket.
 341  *
 342  * Returns the size of data sent, or negative error value.
 343  */
 344 ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 345 {
 346         struct msghdr msg;
 347         struct cmsghdr *cmptr;
 348         struct iovec iov[1];
 349         ssize_t ret = -1;
 350         unsigned int sizeof_fds = nb_fd * sizeof(int);
 351         char tmp[CMSG_SPACE(sizeof_fds)];
 352         char dummy = 0;
 353
 354         memset(&msg, 0, sizeof(msg));
 355
 356         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 357                 return -EINVAL;
 358
 359         msg.msg_control = (caddr_t)tmp;
 360         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 361
 362         cmptr = CMSG_FIRSTHDR(&msg);
 363         cmptr->cmsg_level = SOL_SOCKET;
 364         cmptr->cmsg_type = SCM_RIGHTS;
 365         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 366         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 367         /* Sum of the length of all control messages in the buffer: */
 368         msg.msg_controllen = cmptr->cmsg_len;
 369
 370         iov[0].iov_base = &dummy;
 371         iov[0].iov_len = 1;
 372         msg.msg_iov = iov;
 373         msg.msg_iovlen = 1;
 374
 375         do {
 376                 ret = sendmsg(sock, &msg, 0);
 377         } while (ret < 0 && errno == EINTR);
 378         if (ret < 0) {
 379                 /*
 380                  * Only warn about EPIPE when quiet mode is deactivated.
 381                  * We consider EPIPE as expected.
 382                  */
 383                 if (errno != EPIPE || !lttng_opt_quiet) {
 384                         PERROR("sendmsg");
 385                 }
 386         }
 387         return ret;
 388 }
 389
 390 /*
 391  * Recv a message accompanied by fd(s) from a unix socket.
 392  *
 393  * Returns the size of received data, or negative error value.
 394  *
 395  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 396  * actually received in nb_fd.
 397  */
 398 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 399 {
 400         struct iovec iov[1];
 401         ssize_t ret = 0;
 402         struct cmsghdr *cmsg;
 403         size_t sizeof_fds = nb_fd * sizeof(int);
 404         char recv_fd[CMSG_SPACE(sizeof_fds)];
 405         struct msghdr msg;
 406         char dummy;
 407
 408         memset(&msg, 0, sizeof(msg));
 409
 410         /* Prepare to receive the structures */
 411         iov[0].iov_base = &dummy;
 412         iov[0].iov_len = 1;
 413         msg.msg_iov = iov;
 414         msg.msg_iovlen = 1;
 415         msg.msg_control = recv_fd;
 416         msg.msg_controllen = sizeof(recv_fd);
 417
 418         do {
 419                 ret = recvmsg(sock, &msg, 0);
 420         } while (ret < 0 && errno == EINTR);
 421         if (ret < 0) {
 422                 PERROR("recvmsg fds");
 423                 goto end;
 424         }
 425         if (ret != 1) {
 426                 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 427                                 ret, 1);
 428                 goto end;
 429         }
 430         if (msg.msg_flags & MSG_CTRUNC) {
 431                 fprintf(stderr, "Error: Control message truncated.\n");
 432                 ret = -1;
 433                 goto end;
 434         }
 435         cmsg = CMSG_FIRSTHDR(&msg);
 436         if (!cmsg) {
 437                 fprintf(stderr, "Error: Invalid control message header\n");
 438                 ret = -1;
 439                 goto end;
 440         }
 441         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 442                 fprintf(stderr, "Didn't received any fd\n");
 443                 ret = -1;
 444                 goto end;
 445         }
 446         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 447                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 448                                 (size_t) cmsg->cmsg_len, (size_t) CMSG_LEN(sizeof_fds));
 449                 ret = -1;
 450                 goto end;
 451         }
 452         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 453         ret = sizeof_fds;
 454 end:
 455         return ret;
 456 }
 457
 458 /*
 459  * Send a message with credentials over a unix socket.
 460  *
 461  * Returns the size of data sent, or negative error value.
 462  */
 463 ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
 464 {
 465         struct msghdr msg;
 466         struct iovec iov[1];
 467         ssize_t ret = -1;
 468 #ifdef __linux__
 469         struct cmsghdr *cmptr;
 470         size_t sizeof_cred = sizeof(lttng_sock_cred);
 471         char anc_buf[CMSG_SPACE(sizeof_cred)];
 472         lttng_sock_cred *creds;
 473 #endif /* __linux__ */
 474
 475         memset(&msg, 0, sizeof(msg));
 476
 477         iov[0].iov_base = buf;
 478         iov[0].iov_len = len;
 479         msg.msg_iov = iov;
 480         msg.msg_iovlen = 1;
 481
 482 #ifdef __linux__
 483         msg.msg_control = (caddr_t) anc_buf;
 484         msg.msg_controllen = CMSG_LEN(sizeof_cred);
 485
 486         cmptr = CMSG_FIRSTHDR(&msg);
 487         cmptr->cmsg_level = SOL_SOCKET;
 488         cmptr->cmsg_type = LTTNG_SOCK_CREDS;
 489         cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
 490
 491         creds = (lttng_sock_cred*) CMSG_DATA(cmptr);
 492
 493         LTTNG_SOCK_SET_UID_CRED(creds, geteuid());
 494         LTTNG_SOCK_SET_GID_CRED(creds, getegid());
 495         LTTNG_SOCK_SET_PID_CRED(creds, getpid());
 496 #endif /* __linux__ */
 497
 498         do {
 499                 ret = sendmsg(sock, &msg, 0);
 500         } while (ret < 0 && errno == EINTR);
 501         if (ret < 0) {
 502                 /*
 503                  * Only warn about EPIPE when quiet mode is deactivated.
 504                  * We consider EPIPE as expected.
 505                  */
 506                 if (errno != EPIPE || !lttng_opt_quiet) {
 507                         PERROR("sendmsg");
 508                 }
 509         }
 510         return ret;
 511 }
 512
 513 /*
 514  * Recv a message accompanied with credentials from a unix socket.
 515  *
 516  * Returns the size of received data, or negative error value.
 517  */
 518 ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
 519                 lttng_sock_cred *creds)
 520 {
 521         struct msghdr msg;
 522         struct iovec iov[1];
 523         ssize_t ret;
 524 #ifdef __linux__
 525         struct cmsghdr *cmptr;
 526         size_t sizeof_cred = sizeof(lttng_sock_cred);
 527         char anc_buf[CMSG_SPACE(sizeof_cred)];
 528 #endif  /* __linux__ */
 529
 530         memset(&msg, 0, sizeof(msg));
 531
 532         /* Not allowed */
 533         if (creds == NULL) {
 534                 ret = -1;
 535                 goto end;
 536         }
 537
 538         /* Prepare to receive the structures */
 539         iov[0].iov_base = buf;
 540         iov[0].iov_len = len;
 541         msg.msg_iov = iov;
 542         msg.msg_iovlen = 1;
 543
 544 #ifdef __linux__
 545         msg.msg_control = anc_buf;
 546         msg.msg_controllen = sizeof(anc_buf);
 547 #endif /* __linux__ */
 548
 549         do {
 550                 ret = recvmsg(sock, &msg, 0);
 551         } while (ret < 0 && errno == EINTR);
 552         if (ret < 0) {
 553                 PERROR("recvmsg fds");
 554                 goto end;
 555         }
 556
 557 #ifdef __linux__
 558         if (msg.msg_flags & MSG_CTRUNC) {
 559                 fprintf(stderr, "Error: Control message truncated.\n");
 560                 ret = -1;
 561                 goto end;
 562         }
 563
 564         cmptr = CMSG_FIRSTHDR(&msg);
 565         if (cmptr == NULL) {
 566                 fprintf(stderr, "Error: Invalid control message header\n");
 567                 ret = -1;
 568                 goto end;
 569         }
 570
 571         if (cmptr->cmsg_level != SOL_SOCKET ||
 572                         cmptr->cmsg_type != LTTNG_SOCK_CREDS) {
 573                 fprintf(stderr, "Didn't received any credentials\n");
 574                 ret = -1;
 575                 goto end;
 576         }
 577
 578         if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
 579                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 580                                 (size_t) cmptr->cmsg_len, (size_t) CMSG_LEN(sizeof_cred));
 581                 ret = -1;
 582                 goto end;
 583         }
 584
 585         memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
 586 #elif defined(__FreeBSD__)
 587         {
 588                 int peer_ret;
 589
 590                 peer_ret = getpeereid(sock, &creds->uid, &creds->gid);
 591                 if (peer_ret != 0) {
 592                         return peer_ret;
 593                 }
 594         }
 595 #else
 596 #error "Please implement credential support for your OS."
 597 #endif  /* __linux__ */
 598
 599 end:
 600         return ret;
 601 }
 602
 603 /*
 604  * Set socket option to use credentials passing.
 605  */
 606 #ifdef __linux__
 607 int lttcomm_setsockopt_creds_unix_sock(int sock)
 608 {
 609         int ret, on = 1;
 610
 611         /* Set socket for credentials retrieval */
 612         ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 613         if (ret < 0) {
 614                 PERROR("setsockopt creds unix sock");
 615         }
 616         return ret;
 617 }
 618 #elif defined(__FreeBSD__)
 619 int lttcomm_setsockopt_creds_unix_sock(int sock)
 620 {
 621         return 0;
 622 }
 623 #else
 624 #error "Please implement credential support for your OS."
 625 #endif /* __linux__ */