src/common/sessiond-comm/unix.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 "unix.h"
  34
  35 /*
  36  * Connect to unix socket using the path name.
  37  */
  38 __attribute__((visibility("hidden")))
  39 int lttcomm_connect_unix_sock(const char *pathname)
  40 {
  41         struct sockaddr_un sun;
  42         int fd, ret, closeret;
  43
  44         fd = socket(PF_UNIX, SOCK_STREAM, 0);
  45         if (fd < 0) {
  46                 PERROR("socket");
  47                 ret = fd;
  48                 goto error;
  49         }
  50
  51         memset(&sun, 0, sizeof(sun));
  52         sun.sun_family = AF_UNIX;
  53         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
  54         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
  55
  56         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
  57         if (ret < 0) {
  58                 /*
  59                  * Don't print message on connect error, because connect is used in
  60                  * normal execution to detect if sessiond is alive.
  61                  */
  62                 goto error_connect;
  63         }
  64
  65         return fd;
  66
  67 error_connect:
  68         closeret = close(fd);
  69         if (closeret) {
  70                 PERROR("close");
  71         }
  72 error:
  73         return ret;
  74 }
  75
  76 /*
  77  * Do an accept(2) on the sock and return the new file descriptor. The socket
  78  * MUST be bind(2) before.
  79  */
  80 __attribute__((visibility("hidden")))
  81 int lttcomm_accept_unix_sock(int sock)
  82 {
  83         int new_fd;
  84         struct sockaddr_un sun;
  85         socklen_t len = 0;
  86
  87         /* Blocking call */
  88         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
  89         if (new_fd < 0) {
  90                 PERROR("accept");
  91         }
  92
  93         return new_fd;
  94 }
  95
  96 /*
  97  * Creates a AF_UNIX local socket using pathname bind the socket upon creation
  98  * and return the fd.
  99  */
 100 __attribute__((visibility("hidden")))
 101 int lttcomm_create_unix_sock(const char *pathname)
 102 {
 103         struct sockaddr_un sun;
 104         int fd;
 105         int ret = -1;
 106
 107         /* Create server socket */
 108         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 109                 PERROR("socket");
 110                 goto error;
 111         }
 112
 113         memset(&sun, 0, sizeof(sun));
 114         sun.sun_family = AF_UNIX;
 115         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 116         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 117
 118         /* Unlink the old file if present */
 119         (void) unlink(pathname);
 120         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 121         if (ret < 0) {
 122                 PERROR("bind");
 123                 goto error;
 124         }
 125
 126         return fd;
 127
 128 error:
 129         return ret;
 130 }
 131
 132 /*
 133  * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
 134  */
 135 __attribute__((visibility("hidden")))
 136 int lttcomm_listen_unix_sock(int sock)
 137 {
 138         int ret;
 139
 140         ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
 141         if (ret < 0) {
 142                 PERROR("listen");
 143         }
 144
 145         return ret;
 146 }
 147
 148 /*
 149  * Receive data of size len in put that data into the buf param. Using recvmsg
 150  * API.
 151  *
 152  * Return the size of received data.
 153  */
 154 __attribute__((visibility("hidden")))
 155 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 156 {
 157         struct msghdr msg;
 158         struct iovec iov[1];
 159         ssize_t ret = -1;
 160         size_t len_last;
 161
 162         memset(&msg, 0, sizeof(msg));
 163
 164         iov[0].iov_base = buf;
 165         iov[0].iov_len = len;
 166         msg.msg_iov = iov;
 167         msg.msg_iovlen = 1;
 168
 169         do {
 170                 len_last = iov[0].iov_len;
 171                 ret = recvmsg(sock, &msg, 0);
 172                 if (ret > 0) {
 173                         iov[0].iov_base += ret;
 174                         iov[0].iov_len -= ret;
 175                         assert(ret <= len_last);
 176                 }
 177         } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
 178         if (ret < 0) {
 179                 PERROR("recvmsg");
 180         } else if (ret > 0) {
 181                 ret = len;
 182         }
 183         /* Else ret = 0 meaning an orderly shutdown. */
 184
 185         return ret;
 186 }
 187
 188 /*
 189  * Send buf data of size len. Using sendmsg API.
 190  *
 191  * Return the size of sent data.
 192  */
 193 __attribute__((visibility("hidden")))
 194 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
 195 {
 196         struct msghdr msg;
 197         struct iovec iov[1];
 198         ssize_t ret = -1;
 199
 200         memset(&msg, 0, sizeof(msg));
 201
 202         iov[0].iov_base = buf;
 203         iov[0].iov_len = len;
 204         msg.msg_iov = iov;
 205         msg.msg_iovlen = 1;
 206
 207         ret = sendmsg(sock, &msg, 0);
 208         if (ret < 0) {
 209                 /*
 210                  * Only warn about EPIPE when quiet mode is deactivated.
 211                  * We consider EPIPE as expected.
 212                  */
 213                 if (errno != EPIPE || !lttng_opt_quiet) {
 214                         PERROR("sendmsg");
 215                 }
 216         }
 217
 218         return ret;
 219 }
 220
 221 /*
 222  * Shutdown cleanly a unix socket.
 223  */
 224 __attribute__((visibility("hidden")))
 225 int lttcomm_close_unix_sock(int sock)
 226 {
 227         int ret, closeret;
 228
 229         /* Shutdown receptions and transmissions */
 230         ret = shutdown(sock, SHUT_RDWR);
 231         if (ret < 0) {
 232                 PERROR("shutdown");
 233         }
 234
 235         closeret = close(sock);
 236         if (closeret) {
 237                 PERROR("close");
 238         }
 239
 240         return ret;
 241 }
 242
 243 /*
 244  * Send a message accompanied by fd(s) over a unix socket.
 245  *
 246  * Returns the size of data sent, or negative error value.
 247  */
 248 __attribute__((visibility("hidden")))
 249 ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 250 {
 251         struct msghdr msg;
 252         struct cmsghdr *cmptr;
 253         struct iovec iov[1];
 254         ssize_t ret = -1;
 255         unsigned int sizeof_fds = nb_fd * sizeof(int);
 256         char tmp[CMSG_SPACE(sizeof_fds)];
 257         char dummy = 0;
 258
 259         memset(&msg, 0, sizeof(msg));
 260         memset(tmp, 0, CMSG_SPACE(sizeof_fds) * sizeof(char));
 261
 262         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 263                 return -EINVAL;
 264
 265         msg.msg_control = (caddr_t)tmp;
 266         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 267
 268         cmptr = CMSG_FIRSTHDR(&msg);
 269         cmptr->cmsg_level = SOL_SOCKET;
 270         cmptr->cmsg_type = SCM_RIGHTS;
 271         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 272         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 273         /* Sum of the length of all control messages in the buffer: */
 274         msg.msg_controllen = cmptr->cmsg_len;
 275
 276         iov[0].iov_base = &dummy;
 277         iov[0].iov_len = 1;
 278         msg.msg_iov = iov;
 279         msg.msg_iovlen = 1;
 280
 281         do {
 282                 ret = sendmsg(sock, &msg, 0);
 283         } while (ret < 0 && errno == EINTR);
 284         if (ret < 0) {
 285                 /*
 286                  * Only warn about EPIPE when quiet mode is deactivated.
 287                  * We consider EPIPE as expected.
 288                  */
 289                 if (errno != EPIPE || !lttng_opt_quiet) {
 290                         PERROR("sendmsg");
 291                 }
 292         }
 293         return ret;
 294 }
 295
 296 /*
 297  * Recv a message accompanied by fd(s) from a unix socket.
 298  *
 299  * Returns the size of received data, or negative error value.
 300  *
 301  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 302  * actually received in nb_fd.
 303  */
 304 __attribute__((visibility("hidden")))
 305 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 306 {
 307         struct iovec iov[1];
 308         ssize_t ret = 0;
 309         struct cmsghdr *cmsg;
 310         size_t sizeof_fds = nb_fd * sizeof(int);
 311         char recv_fd[CMSG_SPACE(sizeof_fds)];
 312         struct msghdr msg;
 313         char dummy;
 314
 315         memset(&msg, 0, sizeof(msg));
 316
 317         /* Prepare to receive the structures */
 318         iov[0].iov_base = &dummy;
 319         iov[0].iov_len = 1;
 320         msg.msg_iov = iov;
 321         msg.msg_iovlen = 1;
 322         msg.msg_control = recv_fd;
 323         msg.msg_controllen = sizeof(recv_fd);
 324
 325         do {
 326                 ret = recvmsg(sock, &msg, 0);
 327         } while (ret < 0 && errno == EINTR);
 328         if (ret < 0) {
 329                 PERROR("recvmsg fds");
 330                 goto end;
 331         }
 332         if (ret != 1) {
 333                 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 334                                 ret, 1);
 335                 goto end;
 336         }
 337         if (msg.msg_flags & MSG_CTRUNC) {
 338                 fprintf(stderr, "Error: Control message truncated.\n");
 339                 ret = -1;
 340                 goto end;
 341         }
 342         cmsg = CMSG_FIRSTHDR(&msg);
 343         if (!cmsg) {
 344                 fprintf(stderr, "Error: Invalid control message header\n");
 345                 ret = -1;
 346                 goto end;
 347         }
 348         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 349                 fprintf(stderr, "Didn't received any fd\n");
 350                 ret = -1;
 351                 goto end;
 352         }
 353         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 354                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 355                                 (size_t) cmsg->cmsg_len, (size_t) CMSG_LEN(sizeof_fds));
 356                 ret = -1;
 357                 goto end;
 358         }
 359         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 360         ret = sizeof_fds;
 361 end:
 362         return ret;
 363 }
 364
 365 /*
 366  * Send a message with credentials over a unix socket.
 367  *
 368  * Returns the size of data sent, or negative error value.
 369  */
 370 __attribute__((visibility("hidden")))
 371 ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
 372 {
 373         struct msghdr msg;
 374         struct iovec iov[1];
 375         ssize_t ret = -1;
 376 #ifdef __linux__
 377         struct cmsghdr *cmptr;
 378         size_t sizeof_cred = sizeof(lttng_sock_cred);
 379         char anc_buf[CMSG_SPACE(sizeof_cred)];
 380         lttng_sock_cred *creds;
 381 #endif /* __linux__ */
 382
 383         memset(&msg, 0, sizeof(msg));
 384         memset(anc_buf, 0, CMSG_SPACE(sizeof_cred) * sizeof(char));
 385
 386         iov[0].iov_base = buf;
 387         iov[0].iov_len = len;
 388         msg.msg_iov = iov;
 389         msg.msg_iovlen = 1;
 390
 391 #ifdef __linux__
 392         msg.msg_control = (caddr_t) anc_buf;
 393         msg.msg_controllen = CMSG_LEN(sizeof_cred);
 394
 395         cmptr = CMSG_FIRSTHDR(&msg);
 396         cmptr->cmsg_level = SOL_SOCKET;
 397         cmptr->cmsg_type = LTTNG_SOCK_CREDS;
 398         cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
 399
 400         creds = (lttng_sock_cred*) CMSG_DATA(cmptr);
 401
 402         LTTNG_SOCK_SET_UID_CRED(creds, geteuid());
 403         LTTNG_SOCK_SET_GID_CRED(creds, getegid());
 404         LTTNG_SOCK_SET_PID_CRED(creds, getpid());
 405 #endif /* __linux__ */
 406
 407         do {
 408                 ret = sendmsg(sock, &msg, 0);
 409         } while (ret < 0 && errno == EINTR);
 410         if (ret < 0) {
 411                 /*
 412                  * Only warn about EPIPE when quiet mode is deactivated.
 413                  * We consider EPIPE as expected.
 414                  */
 415                 if (errno != EPIPE || !lttng_opt_quiet) {
 416                         PERROR("sendmsg");
 417                 }
 418         }
 419         return ret;
 420 }
 421
 422 /*
 423  * Recv a message accompanied with credentials from a unix socket.
 424  *
 425  * Returns the size of received data, or negative error value.
 426  */
 427 __attribute__((visibility("hidden")))
 428 ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
 429                 lttng_sock_cred *creds)
 430 {
 431         struct msghdr msg;
 432         struct iovec iov[1];
 433         ssize_t ret;
 434 #ifdef __linux__
 435         struct cmsghdr *cmptr;
 436         size_t sizeof_cred = sizeof(lttng_sock_cred);
 437         char anc_buf[CMSG_SPACE(sizeof_cred)];
 438 #endif  /* __linux__ */
 439
 440         memset(&msg, 0, sizeof(msg));
 441
 442         /* Not allowed */
 443         if (creds == NULL) {
 444                 ret = -1;
 445                 goto end;
 446         }
 447
 448         /* Prepare to receive the structures */
 449         iov[0].iov_base = buf;
 450         iov[0].iov_len = len;
 451         msg.msg_iov = iov;
 452         msg.msg_iovlen = 1;
 453
 454 #ifdef __linux__
 455         msg.msg_control = anc_buf;
 456         msg.msg_controllen = sizeof(anc_buf);
 457 #endif /* __linux__ */
 458
 459         do {
 460                 ret = recvmsg(sock, &msg, 0);
 461         } while (ret < 0 && errno == EINTR);
 462         if (ret < 0) {
 463                 PERROR("recvmsg fds");
 464                 goto end;
 465         }
 466
 467 #ifdef __linux__
 468         if (msg.msg_flags & MSG_CTRUNC) {
 469                 fprintf(stderr, "Error: Control message truncated.\n");
 470                 ret = -1;
 471                 goto end;
 472         }
 473
 474         cmptr = CMSG_FIRSTHDR(&msg);
 475         if (cmptr == NULL) {
 476                 fprintf(stderr, "Error: Invalid control message header\n");
 477                 ret = -1;
 478                 goto end;
 479         }
 480
 481         if (cmptr->cmsg_level != SOL_SOCKET ||
 482                         cmptr->cmsg_type != LTTNG_SOCK_CREDS) {
 483                 fprintf(stderr, "Didn't received any credentials\n");
 484                 ret = -1;
 485                 goto end;
 486         }
 487
 488         if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
 489                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 490                                 (size_t) cmptr->cmsg_len, (size_t) CMSG_LEN(sizeof_cred));
 491                 ret = -1;
 492                 goto end;
 493         }
 494
 495         memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
 496 #elif (defined(__FreeBSD__) || defined(__CYGWIN__))
 497         {
 498                 int peer_ret;
 499
 500                 peer_ret = getpeereid(sock, &creds->uid, &creds->gid);
 501                 if (peer_ret != 0) {
 502                         return peer_ret;
 503                 }
 504         }
 505 #else
 506 #error "Please implement credential support for your OS."
 507 #endif  /* __linux__ */
 508
 509 end:
 510         return ret;
 511 }
 512
 513 /*
 514  * Set socket option to use credentials passing.
 515  */
 516 #ifdef __linux__
 517 __attribute__((visibility("hidden")))
 518 int lttcomm_setsockopt_creds_unix_sock(int sock)
 519 {
 520         int ret, on = 1;
 521
 522         /* Set socket for credentials retrieval */
 523         ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 524         if (ret < 0) {
 525                 PERROR("setsockopt creds unix sock");
 526         }
 527         return ret;
 528 }
 529 #elif (defined(__FreeBSD__) || defined(__CYGWIN__))
 530 __attribute__((visibility("hidden")))
 531 int lttcomm_setsockopt_creds_unix_sock(int sock)
 532 {
 533         return 0;
 534 }
 535 #else
 536 #error "Please implement credential support for your OS."
 537 #endif /* __linux__ */
 538
 539 /*
 540  * Set socket reciving timeout.
 541  */
 542 __attribute__((visibility("hidden")))
 543 int lttcomm_setsockopt_rcv_timeout(int sock, unsigned int sec)
 544 {
 545         int ret;
 546         struct timeval tv;
 547
 548         tv.tv_sec = sec;
 549         tv.tv_usec = 0;
 550
 551         ret = setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
 552         if (ret < 0) {
 553                 PERROR("setsockopt SO_RCVTIMEO");
 554                 ret = -errno;
 555         }
 556
 557         return ret;
 558 }
 559
 560 /*
 561  * Set socket sending timeout.
 562  */
 563 __attribute__((visibility("hidden")))
 564 int lttcomm_setsockopt_snd_timeout(int sock, unsigned int sec)
 565 {
 566         int ret;
 567         struct timeval tv;
 568
 569         tv.tv_sec = sec;
 570         tv.tv_usec = 0;
 571
 572         ret = setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
 573         if (ret < 0) {
 574                 PERROR("setsockopt SO_SNDTIMEO");
 575                 ret = -errno;
 576         }
 577
 578         return ret;
 579 }