| 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/common.h> |
| 31 | |
| 32 | #include "unix.h" |
| 33 | |
| 34 | /* |
| 35 | * Connect to unix socket using the path name. |
| 36 | */ |
| 37 | LTTNG_HIDDEN |
| 38 | int lttcomm_connect_unix_sock(const char *pathname) |
| 39 | { |
| 40 | struct sockaddr_un sun; |
| 41 | int fd, ret, closeret; |
| 42 | |
| 43 | fd = socket(PF_UNIX, SOCK_STREAM, 0); |
| 44 | if (fd < 0) { |
| 45 | PERROR("socket"); |
| 46 | ret = fd; |
| 47 | goto error; |
| 48 | } |
| 49 | |
| 50 | memset(&sun, 0, sizeof(sun)); |
| 51 | sun.sun_family = AF_UNIX; |
| 52 | strncpy(sun.sun_path, pathname, sizeof(sun.sun_path)); |
| 53 | sun.sun_path[sizeof(sun.sun_path) - 1] = '\0'; |
| 54 | |
| 55 | ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun)); |
| 56 | if (ret < 0) { |
| 57 | /* |
| 58 | * Don't print message on connect error, because connect is used in |
| 59 | * normal execution to detect if sessiond is alive. |
| 60 | */ |
| 61 | goto error_connect; |
| 62 | } |
| 63 | |
| 64 | return fd; |
| 65 | |
| 66 | error_connect: |
| 67 | closeret = close(fd); |
| 68 | if (closeret) { |
| 69 | PERROR("close"); |
| 70 | } |
| 71 | error: |
| 72 | return ret; |
| 73 | } |
| 74 | |
| 75 | /* |
| 76 | * Do an accept(2) on the sock and return the new file descriptor. The socket |
| 77 | * MUST be bind(2) before. |
| 78 | */ |
| 79 | LTTNG_HIDDEN |
| 80 | int lttcomm_accept_unix_sock(int sock) |
| 81 | { |
| 82 | int new_fd; |
| 83 | struct sockaddr_un sun; |
| 84 | socklen_t len = 0; |
| 85 | |
| 86 | /* Blocking call */ |
| 87 | new_fd = accept(sock, (struct sockaddr *) &sun, &len); |
| 88 | if (new_fd < 0) { |
| 89 | PERROR("accept"); |
| 90 | } |
| 91 | |
| 92 | return new_fd; |
| 93 | } |
| 94 | |
| 95 | /* |
| 96 | * Creates a AF_UNIX local socket using pathname bind the socket upon creation |
| 97 | * and return the fd. |
| 98 | */ |
| 99 | LTTNG_HIDDEN |
| 100 | int lttcomm_create_unix_sock(const char *pathname) |
| 101 | { |
| 102 | struct sockaddr_un sun; |
| 103 | int fd; |
| 104 | int ret = -1; |
| 105 | |
| 106 | /* Create server socket */ |
| 107 | if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) { |
| 108 | PERROR("socket"); |
| 109 | goto error; |
| 110 | } |
| 111 | |
| 112 | memset(&sun, 0, sizeof(sun)); |
| 113 | sun.sun_family = AF_UNIX; |
| 114 | strncpy(sun.sun_path, pathname, sizeof(sun.sun_path)); |
| 115 | sun.sun_path[sizeof(sun.sun_path) - 1] = '\0'; |
| 116 | |
| 117 | /* Unlink the old file if present */ |
| 118 | (void) unlink(pathname); |
| 119 | ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun)); |
| 120 | if (ret < 0) { |
| 121 | PERROR("bind"); |
| 122 | goto error; |
| 123 | } |
| 124 | |
| 125 | return fd; |
| 126 | |
| 127 | error: |
| 128 | if (fd >= 0) { |
| 129 | if (close(fd) < 0) { |
| 130 | PERROR("close create unix sock"); |
| 131 | } |
| 132 | } |
| 133 | return ret; |
| 134 | } |
| 135 | |
| 136 | /* |
| 137 | * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN. |
| 138 | */ |
| 139 | LTTNG_HIDDEN |
| 140 | int lttcomm_listen_unix_sock(int sock) |
| 141 | { |
| 142 | int ret; |
| 143 | |
| 144 | ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN); |
| 145 | if (ret < 0) { |
| 146 | PERROR("listen"); |
| 147 | } |
| 148 | |
| 149 | return ret; |
| 150 | } |
| 151 | |
| 152 | /* |
| 153 | * Receive data of size len in put that data into the buf param. Using recvmsg |
| 154 | * API. |
| 155 | * |
| 156 | * Return the size of received data. |
| 157 | */ |
| 158 | LTTNG_HIDDEN |
| 159 | ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len) |
| 160 | { |
| 161 | struct msghdr msg; |
| 162 | struct iovec iov[1]; |
| 163 | ssize_t ret = -1; |
| 164 | size_t len_last; |
| 165 | |
| 166 | memset(&msg, 0, sizeof(msg)); |
| 167 | |
| 168 | iov[0].iov_base = buf; |
| 169 | iov[0].iov_len = len; |
| 170 | msg.msg_iov = iov; |
| 171 | msg.msg_iovlen = 1; |
| 172 | |
| 173 | do { |
| 174 | len_last = iov[0].iov_len; |
| 175 | ret = recvmsg(sock, &msg, MSG_NOSIGNAL); |
| 176 | if (ret > 0) { |
| 177 | iov[0].iov_base += ret; |
| 178 | iov[0].iov_len -= ret; |
| 179 | assert(ret <= len_last); |
| 180 | } |
| 181 | } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR)); |
| 182 | if (ret < 0) { |
| 183 | PERROR("recvmsg"); |
| 184 | } else if (ret > 0) { |
| 185 | ret = len; |
| 186 | } |
| 187 | /* Else ret = 0 meaning an orderly shutdown. */ |
| 188 | |
| 189 | return ret; |
| 190 | } |
| 191 | |
| 192 | /* |
| 193 | * Send buf data of size len. Using sendmsg API. |
| 194 | * |
| 195 | * Return the size of sent data. |
| 196 | */ |
| 197 | LTTNG_HIDDEN |
| 198 | ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len) |
| 199 | { |
| 200 | struct msghdr msg; |
| 201 | struct iovec iov[1]; |
| 202 | ssize_t ret = -1; |
| 203 | |
| 204 | memset(&msg, 0, sizeof(msg)); |
| 205 | |
| 206 | iov[0].iov_base = buf; |
| 207 | iov[0].iov_len = len; |
| 208 | msg.msg_iov = iov; |
| 209 | msg.msg_iovlen = 1; |
| 210 | |
| 211 | ret = sendmsg(sock, &msg, 0); |
| 212 | if (ret < 0) { |
| 213 | /* |
| 214 | * Only warn about EPIPE when quiet mode is deactivated. |
| 215 | * We consider EPIPE as expected. |
| 216 | */ |
| 217 | if (errno != EPIPE || !lttng_opt_quiet) { |
| 218 | PERROR("sendmsg"); |
| 219 | } |
| 220 | } |
| 221 | |
| 222 | return ret; |
| 223 | } |
| 224 | |
| 225 | /* |
| 226 | * Shutdown cleanly a unix socket. |
| 227 | */ |
| 228 | LTTNG_HIDDEN |
| 229 | int lttcomm_close_unix_sock(int sock) |
| 230 | { |
| 231 | int ret, closeret; |
| 232 | |
| 233 | /* Shutdown receptions and transmissions */ |
| 234 | ret = shutdown(sock, SHUT_RDWR); |
| 235 | if (ret < 0) { |
| 236 | PERROR("shutdown"); |
| 237 | } |
| 238 | |
| 239 | closeret = close(sock); |
| 240 | if (closeret) { |
| 241 | PERROR("close"); |
| 242 | } |
| 243 | |
| 244 | return ret; |
| 245 | } |
| 246 | |
| 247 | /* |
| 248 | * Send a message accompanied by fd(s) over a unix socket. |
| 249 | * |
| 250 | * Returns the size of data sent, or negative error value. |
| 251 | */ |
| 252 | LTTNG_HIDDEN |
| 253 | ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd) |
| 254 | { |
| 255 | struct msghdr msg; |
| 256 | struct cmsghdr *cmptr; |
| 257 | struct iovec iov[1]; |
| 258 | ssize_t ret = -1; |
| 259 | unsigned int sizeof_fds = nb_fd * sizeof(int); |
| 260 | char tmp[CMSG_SPACE(sizeof_fds)]; |
| 261 | char dummy = 0; |
| 262 | |
| 263 | memset(&msg, 0, sizeof(msg)); |
| 264 | memset(tmp, 0, CMSG_SPACE(sizeof_fds) * sizeof(char)); |
| 265 | |
| 266 | if (nb_fd > LTTCOMM_MAX_SEND_FDS) |
| 267 | return -EINVAL; |
| 268 | |
| 269 | msg.msg_control = (caddr_t)tmp; |
| 270 | msg.msg_controllen = CMSG_LEN(sizeof_fds); |
| 271 | |
| 272 | cmptr = CMSG_FIRSTHDR(&msg); |
| 273 | cmptr->cmsg_level = SOL_SOCKET; |
| 274 | cmptr->cmsg_type = SCM_RIGHTS; |
| 275 | cmptr->cmsg_len = CMSG_LEN(sizeof_fds); |
| 276 | memcpy(CMSG_DATA(cmptr), fds, sizeof_fds); |
| 277 | /* Sum of the length of all control messages in the buffer: */ |
| 278 | msg.msg_controllen = cmptr->cmsg_len; |
| 279 | |
| 280 | iov[0].iov_base = &dummy; |
| 281 | iov[0].iov_len = 1; |
| 282 | msg.msg_iov = iov; |
| 283 | msg.msg_iovlen = 1; |
| 284 | |
| 285 | do { |
| 286 | ret = sendmsg(sock, &msg, 0); |
| 287 | } while (ret < 0 && errno == EINTR); |
| 288 | if (ret < 0) { |
| 289 | /* |
| 290 | * Only warn about EPIPE when quiet mode is deactivated. |
| 291 | * We consider EPIPE as expected. |
| 292 | */ |
| 293 | if (errno != EPIPE || !lttng_opt_quiet) { |
| 294 | PERROR("sendmsg"); |
| 295 | } |
| 296 | } |
| 297 | return ret; |
| 298 | } |
| 299 | |
| 300 | /* |
| 301 | * Recv a message accompanied by fd(s) from a unix socket. |
| 302 | * |
| 303 | * Returns the size of received data, or negative error value. |
| 304 | * |
| 305 | * Expect at most "nb_fd" file descriptors. Returns the number of fd |
| 306 | * actually received in nb_fd. |
| 307 | */ |
| 308 | LTTNG_HIDDEN |
| 309 | ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd) |
| 310 | { |
| 311 | struct iovec iov[1]; |
| 312 | ssize_t ret = 0; |
| 313 | struct cmsghdr *cmsg; |
| 314 | size_t sizeof_fds = nb_fd * sizeof(int); |
| 315 | char recv_fd[CMSG_SPACE(sizeof_fds)]; |
| 316 | struct msghdr msg; |
| 317 | char dummy; |
| 318 | |
| 319 | memset(&msg, 0, sizeof(msg)); |
| 320 | |
| 321 | /* Prepare to receive the structures */ |
| 322 | iov[0].iov_base = &dummy; |
| 323 | iov[0].iov_len = 1; |
| 324 | msg.msg_iov = iov; |
| 325 | msg.msg_iovlen = 1; |
| 326 | msg.msg_control = recv_fd; |
| 327 | msg.msg_controllen = sizeof(recv_fd); |
| 328 | |
| 329 | do { |
| 330 | ret = recvmsg(sock, &msg, 0); |
| 331 | } while (ret < 0 && errno == EINTR); |
| 332 | if (ret < 0) { |
| 333 | PERROR("recvmsg fds"); |
| 334 | goto end; |
| 335 | } |
| 336 | if (ret != 1) { |
| 337 | fprintf(stderr, "Error: Received %zd bytes, expected %d\n", |
| 338 | ret, 1); |
| 339 | goto end; |
| 340 | } |
| 341 | if (msg.msg_flags & MSG_CTRUNC) { |
| 342 | fprintf(stderr, "Error: Control message truncated.\n"); |
| 343 | ret = -1; |
| 344 | goto end; |
| 345 | } |
| 346 | cmsg = CMSG_FIRSTHDR(&msg); |
| 347 | if (!cmsg) { |
| 348 | fprintf(stderr, "Error: Invalid control message header\n"); |
| 349 | ret = -1; |
| 350 | goto end; |
| 351 | } |
| 352 | if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) { |
| 353 | fprintf(stderr, "Didn't received any fd\n"); |
| 354 | ret = -1; |
| 355 | goto end; |
| 356 | } |
| 357 | if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) { |
| 358 | fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n", |
| 359 | (size_t) cmsg->cmsg_len, (size_t) CMSG_LEN(sizeof_fds)); |
| 360 | ret = -1; |
| 361 | goto end; |
| 362 | } |
| 363 | memcpy(fds, CMSG_DATA(cmsg), sizeof_fds); |
| 364 | ret = sizeof_fds; |
| 365 | end: |
| 366 | return ret; |
| 367 | } |
| 368 | |
| 369 | /* |
| 370 | * Send a message with credentials over a unix socket. |
| 371 | * |
| 372 | * Returns the size of data sent, or negative error value. |
| 373 | */ |
| 374 | LTTNG_HIDDEN |
| 375 | ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len) |
| 376 | { |
| 377 | struct msghdr msg; |
| 378 | struct iovec iov[1]; |
| 379 | ssize_t ret = -1; |
| 380 | #ifdef __linux__ |
| 381 | struct cmsghdr *cmptr; |
| 382 | size_t sizeof_cred = sizeof(lttng_sock_cred); |
| 383 | char anc_buf[CMSG_SPACE(sizeof_cred)]; |
| 384 | lttng_sock_cred *creds; |
| 385 | #endif /* __linux__ */ |
| 386 | |
| 387 | memset(&msg, 0, sizeof(msg)); |
| 388 | memset(anc_buf, 0, CMSG_SPACE(sizeof_cred) * sizeof(char)); |
| 389 | |
| 390 | iov[0].iov_base = buf; |
| 391 | iov[0].iov_len = len; |
| 392 | msg.msg_iov = iov; |
| 393 | msg.msg_iovlen = 1; |
| 394 | |
| 395 | #ifdef __linux__ |
| 396 | msg.msg_control = (caddr_t) anc_buf; |
| 397 | msg.msg_controllen = CMSG_LEN(sizeof_cred); |
| 398 | |
| 399 | cmptr = CMSG_FIRSTHDR(&msg); |
| 400 | cmptr->cmsg_level = SOL_SOCKET; |
| 401 | cmptr->cmsg_type = LTTNG_SOCK_CREDS; |
| 402 | cmptr->cmsg_len = CMSG_LEN(sizeof_cred); |
| 403 | |
| 404 | creds = (lttng_sock_cred*) CMSG_DATA(cmptr); |
| 405 | |
| 406 | LTTNG_SOCK_SET_UID_CRED(creds, geteuid()); |
| 407 | LTTNG_SOCK_SET_GID_CRED(creds, getegid()); |
| 408 | LTTNG_SOCK_SET_PID_CRED(creds, getpid()); |
| 409 | #endif /* __linux__ */ |
| 410 | |
| 411 | do { |
| 412 | ret = sendmsg(sock, &msg, 0); |
| 413 | } while (ret < 0 && errno == EINTR); |
| 414 | if (ret < 0) { |
| 415 | /* |
| 416 | * Only warn about EPIPE when quiet mode is deactivated. |
| 417 | * We consider EPIPE as expected. |
| 418 | */ |
| 419 | if (errno != EPIPE || !lttng_opt_quiet) { |
| 420 | PERROR("sendmsg"); |
| 421 | } |
| 422 | } |
| 423 | return ret; |
| 424 | } |
| 425 | |
| 426 | /* |
| 427 | * Recv a message accompanied with credentials from a unix socket. |
| 428 | * |
| 429 | * Returns the size of received data, or negative error value. |
| 430 | */ |
| 431 | LTTNG_HIDDEN |
| 432 | ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len, |
| 433 | lttng_sock_cred *creds) |
| 434 | { |
| 435 | struct msghdr msg; |
| 436 | struct iovec iov[1]; |
| 437 | ssize_t ret; |
| 438 | size_t len_last; |
| 439 | #ifdef __linux__ |
| 440 | struct cmsghdr *cmptr; |
| 441 | size_t sizeof_cred = sizeof(lttng_sock_cred); |
| 442 | char anc_buf[CMSG_SPACE(sizeof_cred)]; |
| 443 | #endif /* __linux__ */ |
| 444 | |
| 445 | memset(&msg, 0, sizeof(msg)); |
| 446 | |
| 447 | /* Not allowed */ |
| 448 | if (creds == NULL) { |
| 449 | ret = -1; |
| 450 | goto end; |
| 451 | } |
| 452 | |
| 453 | /* Prepare to receive the structures */ |
| 454 | iov[0].iov_base = buf; |
| 455 | iov[0].iov_len = len; |
| 456 | msg.msg_iov = iov; |
| 457 | msg.msg_iovlen = 1; |
| 458 | |
| 459 | #ifdef __linux__ |
| 460 | msg.msg_control = anc_buf; |
| 461 | msg.msg_controllen = sizeof(anc_buf); |
| 462 | #endif /* __linux__ */ |
| 463 | |
| 464 | do { |
| 465 | len_last = iov[0].iov_len; |
| 466 | ret = recvmsg(sock, &msg, 0); |
| 467 | if (ret > 0) { |
| 468 | iov[0].iov_base += ret; |
| 469 | iov[0].iov_len -= ret; |
| 470 | assert(ret <= len_last); |
| 471 | } |
| 472 | } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR)); |
| 473 | if (ret < 0) { |
| 474 | PERROR("recvmsg fds"); |
| 475 | goto end; |
| 476 | } else if (ret > 0) { |
| 477 | ret = len; |
| 478 | } |
| 479 | /* Else ret = 0 meaning an orderly shutdown. */ |
| 480 | |
| 481 | #ifdef __linux__ |
| 482 | if (msg.msg_flags & MSG_CTRUNC) { |
| 483 | fprintf(stderr, "Error: Control message truncated.\n"); |
| 484 | ret = -1; |
| 485 | goto end; |
| 486 | } |
| 487 | |
| 488 | cmptr = CMSG_FIRSTHDR(&msg); |
| 489 | if (cmptr == NULL) { |
| 490 | fprintf(stderr, "Error: Invalid control message header\n"); |
| 491 | ret = -1; |
| 492 | goto end; |
| 493 | } |
| 494 | |
| 495 | if (cmptr->cmsg_level != SOL_SOCKET || |
| 496 | cmptr->cmsg_type != LTTNG_SOCK_CREDS) { |
| 497 | fprintf(stderr, "Didn't received any credentials\n"); |
| 498 | ret = -1; |
| 499 | goto end; |
| 500 | } |
| 501 | |
| 502 | if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) { |
| 503 | fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n", |
| 504 | (size_t) cmptr->cmsg_len, (size_t) CMSG_LEN(sizeof_cred)); |
| 505 | ret = -1; |
| 506 | goto end; |
| 507 | } |
| 508 | |
| 509 | memcpy(creds, CMSG_DATA(cmptr), sizeof_cred); |
| 510 | #elif (defined(__FreeBSD__) || defined(__CYGWIN__)) |
| 511 | { |
| 512 | int peer_ret; |
| 513 | |
| 514 | peer_ret = getpeereid(sock, &creds->uid, &creds->gid); |
| 515 | if (peer_ret != 0) { |
| 516 | return peer_ret; |
| 517 | } |
| 518 | } |
| 519 | #else |
| 520 | #error "Please implement credential support for your OS." |
| 521 | #endif /* __linux__ */ |
| 522 | |
| 523 | end: |
| 524 | return ret; |
| 525 | } |
| 526 | |
| 527 | /* |
| 528 | * Set socket option to use credentials passing. |
| 529 | */ |
| 530 | #ifdef __linux__ |
| 531 | LTTNG_HIDDEN |
| 532 | int lttcomm_setsockopt_creds_unix_sock(int sock) |
| 533 | { |
| 534 | int ret, on = 1; |
| 535 | |
| 536 | /* Set socket for credentials retrieval */ |
| 537 | ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)); |
| 538 | if (ret < 0) { |
| 539 | PERROR("setsockopt creds unix sock"); |
| 540 | } |
| 541 | return ret; |
| 542 | } |
| 543 | #elif (defined(__FreeBSD__) || defined(__CYGWIN__)) |
| 544 | LTTNG_HIDDEN |
| 545 | int lttcomm_setsockopt_creds_unix_sock(int sock) |
| 546 | { |
| 547 | return 0; |
| 548 | } |
| 549 | #else |
| 550 | #error "Please implement credential support for your OS." |
| 551 | #endif /* __linux__ */ |