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
 261         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 262                 return -EINVAL;
 263
 264         msg.msg_control = (caddr_t)tmp;
 265         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 266
 267         cmptr = CMSG_FIRSTHDR(&msg);
 268         cmptr->cmsg_level = SOL_SOCKET;
 269         cmptr->cmsg_type = SCM_RIGHTS;
 270         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 271         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 272         /* Sum of the length of all control messages in the buffer: */
 273         msg.msg_controllen = cmptr->cmsg_len;
 274
 275         iov[0].iov_base = &dummy;
 276         iov[0].iov_len = 1;
 277         msg.msg_iov = iov;
 278         msg.msg_iovlen = 1;
 279
 280         do {
 281                 ret = sendmsg(sock, &msg, 0);
 282         } while (ret < 0 && errno == EINTR);
 283         if (ret < 0) {
 284                 /*
 285                  * Only warn about EPIPE when quiet mode is deactivated.
 286                  * We consider EPIPE as expected.
 287                  */
 288                 if (errno != EPIPE || !lttng_opt_quiet) {
 289                         PERROR("sendmsg");
 290                 }
 291         }
 292         return ret;
 293 }
 294
 295 /*
 296  * Recv a message accompanied by fd(s) from a unix socket.
 297  *
 298  * Returns the size of received data, or negative error value.
 299  *
 300  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 301  * actually received in nb_fd.
 302  */
 303 __attribute__((visibility("hidden")))
 304 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 305 {
 306         struct iovec iov[1];
 307         ssize_t ret = 0;
 308         struct cmsghdr *cmsg;
 309         size_t sizeof_fds = nb_fd * sizeof(int);
 310         char recv_fd[CMSG_SPACE(sizeof_fds)];
 311         struct msghdr msg;
 312         char dummy;
 313
 314         memset(&msg, 0, sizeof(msg));
 315
 316         /* Prepare to receive the structures */
 317         iov[0].iov_base = &dummy;
 318         iov[0].iov_len = 1;
 319         msg.msg_iov = iov;
 320         msg.msg_iovlen = 1;
 321         msg.msg_control = recv_fd;
 322         msg.msg_controllen = sizeof(recv_fd);
 323
 324         do {
 325                 ret = recvmsg(sock, &msg, 0);
 326         } while (ret < 0 && errno == EINTR);
 327         if (ret < 0) {
 328                 PERROR("recvmsg fds");
 329                 goto end;
 330         }
 331         if (ret != 1) {
 332                 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 333                                 ret, 1);
 334                 goto end;
 335         }
 336         if (msg.msg_flags & MSG_CTRUNC) {
 337                 fprintf(stderr, "Error: Control message truncated.\n");
 338                 ret = -1;
 339                 goto end;
 340         }
 341         cmsg = CMSG_FIRSTHDR(&msg);
 342         if (!cmsg) {
 343                 fprintf(stderr, "Error: Invalid control message header\n");
 344                 ret = -1;
 345                 goto end;
 346         }
 347         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 348                 fprintf(stderr, "Didn't received any fd\n");
 349                 ret = -1;
 350                 goto end;
 351         }
 352         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 353                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 354                                 (size_t) cmsg->cmsg_len, (size_t) CMSG_LEN(sizeof_fds));
 355                 ret = -1;
 356                 goto end;
 357         }
 358         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 359         ret = sizeof_fds;
 360 end:
 361         return ret;
 362 }
 363
 364 /*
 365  * Send a message with credentials over a unix socket.
 366  *
 367  * Returns the size of data sent, or negative error value.
 368  */
 369 __attribute__((visibility("hidden")))
 370 ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
 371 {
 372         struct msghdr msg;
 373         struct iovec iov[1];
 374         ssize_t ret = -1;
 375 #ifdef __linux__
 376         struct cmsghdr *cmptr;
 377         size_t sizeof_cred = sizeof(lttng_sock_cred);
 378         char anc_buf[CMSG_SPACE(sizeof_cred)];
 379         lttng_sock_cred *creds;
 380 #endif /* __linux__ */
 381
 382         memset(&msg, 0, sizeof(msg));
 383
 384         iov[0].iov_base = buf;
 385         iov[0].iov_len = len;
 386         msg.msg_iov = iov;
 387         msg.msg_iovlen = 1;
 388
 389 #ifdef __linux__
 390         msg.msg_control = (caddr_t) anc_buf;
 391         msg.msg_controllen = CMSG_LEN(sizeof_cred);
 392
 393         cmptr = CMSG_FIRSTHDR(&msg);
 394         cmptr->cmsg_level = SOL_SOCKET;
 395         cmptr->cmsg_type = LTTNG_SOCK_CREDS;
 396         cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
 397
 398         creds = (lttng_sock_cred*) CMSG_DATA(cmptr);
 399
 400         LTTNG_SOCK_SET_UID_CRED(creds, geteuid());
 401         LTTNG_SOCK_SET_GID_CRED(creds, getegid());
 402         LTTNG_SOCK_SET_PID_CRED(creds, getpid());
 403 #endif /* __linux__ */
 404
 405         do {
 406                 ret = sendmsg(sock, &msg, 0);
 407         } while (ret < 0 && errno == EINTR);
 408         if (ret < 0) {
 409                 /*
 410                  * Only warn about EPIPE when quiet mode is deactivated.
 411                  * We consider EPIPE as expected.
 412                  */
 413                 if (errno != EPIPE || !lttng_opt_quiet) {
 414                         PERROR("sendmsg");
 415                 }
 416         }
 417         return ret;
 418 }
 419
 420 /*
 421  * Recv a message accompanied with credentials from a unix socket.
 422  *
 423  * Returns the size of received data, or negative error value.
 424  */
 425 __attribute__((visibility("hidden")))
 426 ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
 427                 lttng_sock_cred *creds)
 428 {
 429         struct msghdr msg;
 430         struct iovec iov[1];
 431         ssize_t ret;
 432 #ifdef __linux__
 433         struct cmsghdr *cmptr;
 434         size_t sizeof_cred = sizeof(lttng_sock_cred);
 435         char anc_buf[CMSG_SPACE(sizeof_cred)];
 436 #endif  /* __linux__ */
 437
 438         memset(&msg, 0, sizeof(msg));
 439
 440         /* Not allowed */
 441         if (creds == NULL) {
 442                 ret = -1;
 443                 goto end;
 444         }
 445
 446         /* Prepare to receive the structures */
 447         iov[0].iov_base = buf;
 448         iov[0].iov_len = len;
 449         msg.msg_iov = iov;
 450         msg.msg_iovlen = 1;
 451
 452 #ifdef __linux__
 453         msg.msg_control = anc_buf;
 454         msg.msg_controllen = sizeof(anc_buf);
 455 #endif /* __linux__ */
 456
 457         do {
 458                 ret = recvmsg(sock, &msg, 0);
 459         } while (ret < 0 && errno == EINTR);
 460         if (ret < 0) {
 461                 PERROR("recvmsg fds");
 462                 goto end;
 463         }
 464
 465 #ifdef __linux__
 466         if (msg.msg_flags & MSG_CTRUNC) {
 467                 fprintf(stderr, "Error: Control message truncated.\n");
 468                 ret = -1;
 469                 goto end;
 470         }
 471
 472         cmptr = CMSG_FIRSTHDR(&msg);
 473         if (cmptr == NULL) {
 474                 fprintf(stderr, "Error: Invalid control message header\n");
 475                 ret = -1;
 476                 goto end;
 477         }
 478
 479         if (cmptr->cmsg_level != SOL_SOCKET ||
 480                         cmptr->cmsg_type != LTTNG_SOCK_CREDS) {
 481                 fprintf(stderr, "Didn't received any credentials\n");
 482                 ret = -1;
 483                 goto end;
 484         }
 485
 486         if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
 487                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 488                                 (size_t) cmptr->cmsg_len, (size_t) CMSG_LEN(sizeof_cred));
 489                 ret = -1;
 490                 goto end;
 491         }
 492
 493         memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
 494 #elif (defined(__FreeBSD__) || defined(__CYGWIN__))
 495         {
 496                 int peer_ret;
 497
 498                 peer_ret = getpeereid(sock, &creds->uid, &creds->gid);
 499                 if (peer_ret != 0) {
 500                         return peer_ret;
 501                 }
 502         }
 503 #else
 504 #error "Please implement credential support for your OS."
 505 #endif  /* __linux__ */
 506
 507 end:
 508         return ret;
 509 }
 510
 511 /*
 512  * Set socket option to use credentials passing.
 513  */
 514 #ifdef __linux__
 515 __attribute__((visibility("hidden")))
 516 int lttcomm_setsockopt_creds_unix_sock(int sock)
 517 {
 518         int ret, on = 1;
 519
 520         /* Set socket for credentials retrieval */
 521         ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 522         if (ret < 0) {
 523                 PERROR("setsockopt creds unix sock");
 524         }
 525         return ret;
 526 }
 527 #elif (defined(__FreeBSD__) || defined(__CYGWIN__))
 528 __attribute__((visibility("hidden")))
 529 int lttcomm_setsockopt_creds_unix_sock(int sock)
 530 {
 531         return 0;
 532 }
 533 #else
 534 #error "Please implement credential support for your OS."
 535 #endif /* __linux__ */
 536
 537 /*
 538  * Set socket reciving timeout.
 539  */
 540 __attribute__((visibility("hidden")))
 541 int lttcomm_setsockopt_rcv_timeout(int sock, unsigned int sec)
 542 {
 543         int ret;
 544         struct timeval tv;
 545
 546         tv.tv_sec = sec;
 547         tv.tv_usec = 0;
 548
 549         ret = setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
 550         if (ret < 0) {
 551                 PERROR("setsockopt SO_RCVTIMEO");
 552                 ret = -errno;
 553         }
 554
 555         return ret;
 556 }
 557
 558 /*
 559  * Set socket sending timeout.
 560  */
 561 __attribute__((visibility("hidden")))
 562 int lttcomm_setsockopt_snd_timeout(int sock, unsigned int sec)
 563 {
 564         int ret;
 565         struct timeval tv;
 566
 567         tv.tv_sec = sec;
 568         tv.tv_usec = 0;
 569
 570         ret = setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
 571         if (ret < 0) {
 572                 PERROR("setsockopt SO_SNDTIMEO");
 573                 ret = -errno;
 574         }
 575
 576         return ret;
 577 }