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