| 1 | /* |
| 2 | * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca> |
| 3 | * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 4 | * |
| 5 | * SPDX-License-Identifier: GPL-2.0-only |
| 6 | * |
| 7 | */ |
| 8 | |
| 9 | #define _LGPL_SOURCE |
| 10 | #include <assert.h> |
| 11 | #include <limits.h> |
| 12 | #include <stdio.h> |
| 13 | #include <stdlib.h> |
| 14 | #include <string.h> |
| 15 | #include <sys/stat.h> |
| 16 | #include <sys/types.h> |
| 17 | #include <unistd.h> |
| 18 | #include <errno.h> |
| 19 | |
| 20 | #include <common/common.h> |
| 21 | #include <common/sessiond-comm/sessiond-comm.h> |
| 22 | |
| 23 | #include "unix.h" |
| 24 | |
| 25 | /* |
| 26 | * Connect to unix socket using the path name. |
| 27 | */ |
| 28 | LTTNG_HIDDEN |
| 29 | int lttcomm_connect_unix_sock(const char *pathname) |
| 30 | { |
| 31 | struct sockaddr_un s_un; |
| 32 | int fd, ret, closeret; |
| 33 | |
| 34 | if (strlen(pathname) >= sizeof(s_un.sun_path)) { |
| 35 | ERR("unix socket address (\"%s\") is longer than the platform's limit (%zu > %zu).", |
| 36 | pathname, strlen(pathname) + 1, |
| 37 | sizeof(s_un.sun_path)); |
| 38 | ret = -ENAMETOOLONG; |
| 39 | goto error; |
| 40 | } |
| 41 | |
| 42 | fd = socket(PF_UNIX, SOCK_STREAM, 0); |
| 43 | if (fd < 0) { |
| 44 | PERROR("socket"); |
| 45 | ret = fd; |
| 46 | goto error; |
| 47 | } |
| 48 | |
| 49 | memset(&s_un, 0, sizeof(s_un)); |
| 50 | s_un.sun_family = AF_UNIX; |
| 51 | strncpy(s_un.sun_path, pathname, sizeof(s_un.sun_path)); |
| 52 | s_un.sun_path[sizeof(s_un.sun_path) - 1] = '\0'; |
| 53 | |
| 54 | ret = connect(fd, (struct sockaddr *) &s_un, sizeof(s_un)); |
| 55 | if (ret < 0) { |
| 56 | /* |
| 57 | * Don't print message on connect error, because connect is used in |
| 58 | * normal execution to detect if sessiond is alive. |
| 59 | */ |
| 60 | goto error_connect; |
| 61 | } |
| 62 | |
| 63 | return fd; |
| 64 | |
| 65 | error_connect: |
| 66 | closeret = close(fd); |
| 67 | if (closeret) { |
| 68 | PERROR("close"); |
| 69 | } |
| 70 | error: |
| 71 | return ret; |
| 72 | } |
| 73 | |
| 74 | /* |
| 75 | * Do an accept(2) on the sock and return the new file descriptor. The socket |
| 76 | * MUST be bind(2) before. |
| 77 | */ |
| 78 | LTTNG_HIDDEN |
| 79 | int lttcomm_accept_unix_sock(int sock) |
| 80 | { |
| 81 | int new_fd; |
| 82 | struct sockaddr_un s_un; |
| 83 | socklen_t len = sizeof(s_un); |
| 84 | |
| 85 | /* Blocking call */ |
| 86 | new_fd = accept(sock, (struct sockaddr *) &s_un, &len); |
| 87 | if (new_fd < 0) { |
| 88 | PERROR("accept"); |
| 89 | } |
| 90 | |
| 91 | return new_fd; |
| 92 | } |
| 93 | |
| 94 | LTTNG_HIDDEN |
| 95 | int lttcomm_create_anon_unix_socketpair(int *fds) |
| 96 | { |
| 97 | if (socketpair(PF_UNIX, SOCK_STREAM, 0, fds) < 0) { |
| 98 | PERROR("socketpair"); |
| 99 | return -1; |
| 100 | } |
| 101 | return 0; |
| 102 | } |
| 103 | |
| 104 | /* |
| 105 | * Creates a AF_UNIX local socket using pathname bind the socket upon creation |
| 106 | * and return the fd. |
| 107 | */ |
| 108 | LTTNG_HIDDEN |
| 109 | int lttcomm_create_unix_sock(const char *pathname) |
| 110 | { |
| 111 | struct sockaddr_un s_un; |
| 112 | int fd = -1; |
| 113 | int ret = -1; |
| 114 | |
| 115 | if (strlen(pathname) >= sizeof(s_un.sun_path)) { |
| 116 | ERR("unix socket address (\"%s\") is longer than the platform's limit (%zu > %zu).", |
| 117 | pathname, strlen(pathname) + 1, |
| 118 | sizeof(s_un.sun_path)); |
| 119 | ret = -ENAMETOOLONG; |
| 120 | goto error; |
| 121 | } |
| 122 | |
| 123 | /* Create server socket */ |
| 124 | if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) { |
| 125 | PERROR("socket"); |
| 126 | goto error; |
| 127 | } |
| 128 | |
| 129 | memset(&s_un, 0, sizeof(s_un)); |
| 130 | s_un.sun_family = AF_UNIX; |
| 131 | strncpy(s_un.sun_path, pathname, sizeof(s_un.sun_path)); |
| 132 | s_un.sun_path[sizeof(s_un.sun_path) - 1] = '\0'; |
| 133 | |
| 134 | /* Unlink the old file if present */ |
| 135 | (void) unlink(pathname); |
| 136 | ret = bind(fd, (struct sockaddr *) &s_un, sizeof(s_un)); |
| 137 | if (ret < 0) { |
| 138 | PERROR("bind"); |
| 139 | goto error; |
| 140 | } |
| 141 | |
| 142 | return fd; |
| 143 | |
| 144 | error: |
| 145 | if (fd >= 0) { |
| 146 | if (close(fd) < 0) { |
| 147 | PERROR("close create unix sock"); |
| 148 | } |
| 149 | } |
| 150 | return ret; |
| 151 | } |
| 152 | |
| 153 | /* |
| 154 | * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN. |
| 155 | */ |
| 156 | LTTNG_HIDDEN |
| 157 | int lttcomm_listen_unix_sock(int sock) |
| 158 | { |
| 159 | int ret; |
| 160 | |
| 161 | ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN); |
| 162 | if (ret < 0) { |
| 163 | PERROR("listen"); |
| 164 | } |
| 165 | |
| 166 | return ret; |
| 167 | } |
| 168 | |
| 169 | /* |
| 170 | * Receive data of size len in put that data into the buf param. Using recvmsg |
| 171 | * API. |
| 172 | * |
| 173 | * Return the size of received data. |
| 174 | */ |
| 175 | LTTNG_HIDDEN |
| 176 | ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len) |
| 177 | { |
| 178 | struct msghdr msg; |
| 179 | struct iovec iov[1]; |
| 180 | ssize_t ret = -1; |
| 181 | size_t len_last; |
| 182 | |
| 183 | memset(&msg, 0, sizeof(msg)); |
| 184 | |
| 185 | iov[0].iov_base = buf; |
| 186 | iov[0].iov_len = len; |
| 187 | msg.msg_iov = iov; |
| 188 | msg.msg_iovlen = 1; |
| 189 | |
| 190 | do { |
| 191 | len_last = iov[0].iov_len; |
| 192 | ret = lttng_recvmsg_nosigpipe(sock, &msg); |
| 193 | if (ret > 0) { |
| 194 | iov[0].iov_base += ret; |
| 195 | iov[0].iov_len -= ret; |
| 196 | assert(ret <= len_last); |
| 197 | } |
| 198 | } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR)); |
| 199 | if (ret < 0) { |
| 200 | PERROR("recvmsg"); |
| 201 | } else if (ret > 0) { |
| 202 | ret = len; |
| 203 | } |
| 204 | /* Else ret = 0 meaning an orderly shutdown. */ |
| 205 | |
| 206 | return ret; |
| 207 | } |
| 208 | |
| 209 | /* |
| 210 | * Receive data of size len in put that data into the buf param. Using recvmsg |
| 211 | * API. Only use with sockets set in non-blocking mode. |
| 212 | * |
| 213 | * NOTE: EPIPE errors are NOT reported. This call expects the socket to be in a |
| 214 | * poll set. The poll loop will handle the EPIPE original cause. |
| 215 | * |
| 216 | * Return the size of received data. |
| 217 | */ |
| 218 | LTTNG_HIDDEN |
| 219 | ssize_t lttcomm_recv_unix_sock_non_block(int sock, void *buf, size_t len) |
| 220 | { |
| 221 | struct msghdr msg; |
| 222 | struct iovec iov[1]; |
| 223 | ssize_t ret; |
| 224 | |
| 225 | memset(&msg, 0, sizeof(msg)); |
| 226 | |
| 227 | iov[0].iov_base = buf; |
| 228 | iov[0].iov_len = len; |
| 229 | msg.msg_iov = iov; |
| 230 | msg.msg_iovlen = 1; |
| 231 | |
| 232 | retry: |
| 233 | ret = lttng_recvmsg_nosigpipe(sock, &msg); |
| 234 | if (ret < 0) { |
| 235 | if (errno == EINTR) { |
| 236 | goto retry; |
| 237 | } else { |
| 238 | /* |
| 239 | * We consider EPIPE and EAGAIN/EWOULDBLOCK as expected. |
| 240 | */ |
| 241 | if (errno == EAGAIN || errno == EWOULDBLOCK || |
| 242 | errno == EPIPE) { |
| 243 | /* |
| 244 | * Nothing was recv. |
| 245 | */ |
| 246 | ret = 0; |
| 247 | goto end; |
| 248 | } |
| 249 | |
| 250 | /* Unexpected error */ |
| 251 | PERROR("recvmsg"); |
| 252 | ret = -1; |
| 253 | goto end; |
| 254 | } |
| 255 | } |
| 256 | ret = len; |
| 257 | end: |
| 258 | return ret; |
| 259 | } |
| 260 | |
| 261 | /* |
| 262 | * Send buf data of size len. Using sendmsg API. |
| 263 | * |
| 264 | * Return the size of sent data. |
| 265 | */ |
| 266 | LTTNG_HIDDEN |
| 267 | ssize_t lttcomm_send_unix_sock(int sock, const void *buf, size_t len) |
| 268 | { |
| 269 | struct msghdr msg; |
| 270 | struct iovec iov[1]; |
| 271 | ssize_t ret; |
| 272 | |
| 273 | memset(&msg, 0, sizeof(msg)); |
| 274 | |
| 275 | iov[0].iov_base = (void *) buf; |
| 276 | iov[0].iov_len = len; |
| 277 | msg.msg_iov = iov; |
| 278 | msg.msg_iovlen = 1; |
| 279 | |
| 280 | while (iov[0].iov_len) { |
| 281 | ret = sendmsg(sock, &msg, 0); |
| 282 | if (ret < 0) { |
| 283 | if (errno == EINTR) { |
| 284 | continue; |
| 285 | } else { |
| 286 | /* |
| 287 | * Only warn about EPIPE when quiet mode is |
| 288 | * deactivated. |
| 289 | * We consider EPIPE as expected. |
| 290 | */ |
| 291 | if (errno != EPIPE || !lttng_opt_quiet) { |
| 292 | PERROR("sendmsg"); |
| 293 | } |
| 294 | goto end; |
| 295 | } |
| 296 | } |
| 297 | iov[0].iov_len -= ret; |
| 298 | iov[0].iov_base += ret; |
| 299 | } |
| 300 | ret = len; |
| 301 | end: |
| 302 | return ret; |
| 303 | } |
| 304 | |
| 305 | /* |
| 306 | * Send buf data of size len. Using sendmsg API. |
| 307 | * Only use with non-blocking sockets. The difference with the blocking version |
| 308 | * of the function is that this one does not retry to send on partial sends, |
| 309 | * except if the interruption was caused by a signal (EINTR). |
| 310 | * |
| 311 | * NOTE: EPIPE errors are NOT reported. This call expects the socket to be in a |
| 312 | * poll set. The poll loop will handle the EPIPE original cause. |
| 313 | * |
| 314 | * Return the size of sent data. |
| 315 | */ |
| 316 | LTTNG_HIDDEN |
| 317 | ssize_t lttcomm_send_unix_sock_non_block(int sock, const void *buf, size_t len) |
| 318 | { |
| 319 | struct msghdr msg; |
| 320 | struct iovec iov[1]; |
| 321 | ssize_t ret; |
| 322 | |
| 323 | memset(&msg, 0, sizeof(msg)); |
| 324 | |
| 325 | iov[0].iov_base = (void *) buf; |
| 326 | iov[0].iov_len = len; |
| 327 | msg.msg_iov = iov; |
| 328 | msg.msg_iovlen = 1; |
| 329 | |
| 330 | retry: |
| 331 | ret = sendmsg(sock, &msg, 0); |
| 332 | if (ret < 0) { |
| 333 | if (errno == EINTR) { |
| 334 | goto retry; |
| 335 | } else { |
| 336 | /* |
| 337 | * We consider EPIPE and EAGAIN/EWOULDBLOCK as expected. |
| 338 | */ |
| 339 | if (errno == EAGAIN || errno == EWOULDBLOCK || |
| 340 | errno == EPIPE) { |
| 341 | /* |
| 342 | * This can happen in non blocking mode. |
| 343 | * Nothing was sent. |
| 344 | */ |
| 345 | ret = 0; |
| 346 | goto end; |
| 347 | } |
| 348 | |
| 349 | /* Unexpected error */ |
| 350 | PERROR("sendmsg"); |
| 351 | ret = -1; |
| 352 | goto end; |
| 353 | } |
| 354 | } |
| 355 | ret = len; |
| 356 | end: |
| 357 | return ret; |
| 358 | } |
| 359 | |
| 360 | /* |
| 361 | * Shutdown cleanly a unix socket. |
| 362 | */ |
| 363 | LTTNG_HIDDEN |
| 364 | int lttcomm_close_unix_sock(int sock) |
| 365 | { |
| 366 | int ret, closeret; |
| 367 | |
| 368 | /* Shutdown receptions and transmissions */ |
| 369 | ret = shutdown(sock, SHUT_RDWR); |
| 370 | if (ret < 0) { |
| 371 | PERROR("shutdown"); |
| 372 | } |
| 373 | |
| 374 | closeret = close(sock); |
| 375 | if (closeret) { |
| 376 | PERROR("close"); |
| 377 | } |
| 378 | |
| 379 | return ret; |
| 380 | } |
| 381 | |
| 382 | /* |
| 383 | * Send a message accompanied by fd(s) over a unix socket. |
| 384 | * |
| 385 | * Returns the size of data sent, or negative error value. |
| 386 | */ |
| 387 | LTTNG_HIDDEN |
| 388 | ssize_t lttcomm_send_fds_unix_sock(int sock, const int *fds, size_t nb_fd) |
| 389 | { |
| 390 | struct msghdr msg; |
| 391 | struct cmsghdr *cmptr; |
| 392 | struct iovec iov[1]; |
| 393 | ssize_t ret = -1; |
| 394 | unsigned int sizeof_fds = nb_fd * sizeof(int); |
| 395 | char tmp[CMSG_SPACE(sizeof_fds)]; |
| 396 | char dummy = 0; |
| 397 | |
| 398 | memset(&msg, 0, sizeof(msg)); |
| 399 | memset(tmp, 0, sizeof(tmp)); |
| 400 | |
| 401 | if (nb_fd > LTTCOMM_MAX_SEND_FDS) |
| 402 | return -EINVAL; |
| 403 | |
| 404 | msg.msg_control = (caddr_t)tmp; |
| 405 | msg.msg_controllen = CMSG_LEN(sizeof_fds); |
| 406 | |
| 407 | cmptr = CMSG_FIRSTHDR(&msg); |
| 408 | if (!cmptr) { |
| 409 | return -1; |
| 410 | } |
| 411 | |
| 412 | cmptr->cmsg_level = SOL_SOCKET; |
| 413 | cmptr->cmsg_type = SCM_RIGHTS; |
| 414 | cmptr->cmsg_len = CMSG_LEN(sizeof_fds); |
| 415 | memcpy(CMSG_DATA(cmptr), fds, sizeof_fds); |
| 416 | /* Sum of the length of all control messages in the buffer: */ |
| 417 | msg.msg_controllen = cmptr->cmsg_len; |
| 418 | |
| 419 | iov[0].iov_base = &dummy; |
| 420 | iov[0].iov_len = 1; |
| 421 | msg.msg_iov = iov; |
| 422 | msg.msg_iovlen = 1; |
| 423 | |
| 424 | do { |
| 425 | ret = sendmsg(sock, &msg, 0); |
| 426 | } while (ret < 0 && errno == EINTR); |
| 427 | if (ret < 0) { |
| 428 | /* |
| 429 | * Only warn about EPIPE when quiet mode is deactivated. |
| 430 | * We consider EPIPE as expected. |
| 431 | */ |
| 432 | if (errno != EPIPE || !lttng_opt_quiet) { |
| 433 | PERROR("sendmsg"); |
| 434 | } |
| 435 | } |
| 436 | return ret; |
| 437 | } |
| 438 | |
| 439 | /* |
| 440 | * Send a message accompanied by fd(s) over a unix socket. |
| 441 | * Only use for non blocking socket. |
| 442 | * |
| 443 | * Returns the size of data sent, or negative error value. |
| 444 | */ |
| 445 | LTTNG_HIDDEN |
| 446 | ssize_t lttcomm_send_fds_unix_sock_non_block(int sock, const int *fds, size_t nb_fd) |
| 447 | { |
| 448 | struct msghdr msg; |
| 449 | struct cmsghdr *cmptr; |
| 450 | struct iovec iov[1]; |
| 451 | ssize_t ret = -1; |
| 452 | unsigned int sizeof_fds = nb_fd * sizeof(int); |
| 453 | char tmp[CMSG_SPACE(sizeof_fds)]; |
| 454 | char dummy = 0; |
| 455 | |
| 456 | memset(&msg, 0, sizeof(msg)); |
| 457 | memset(tmp, 0, sizeof(tmp)); |
| 458 | |
| 459 | if (nb_fd > LTTCOMM_MAX_SEND_FDS) |
| 460 | return -EINVAL; |
| 461 | |
| 462 | msg.msg_control = (caddr_t)tmp; |
| 463 | msg.msg_controllen = CMSG_LEN(sizeof_fds); |
| 464 | |
| 465 | cmptr = CMSG_FIRSTHDR(&msg); |
| 466 | if (!cmptr) { |
| 467 | return -1; |
| 468 | } |
| 469 | |
| 470 | cmptr->cmsg_level = SOL_SOCKET; |
| 471 | cmptr->cmsg_type = SCM_RIGHTS; |
| 472 | cmptr->cmsg_len = CMSG_LEN(sizeof_fds); |
| 473 | memcpy(CMSG_DATA(cmptr), fds, sizeof_fds); |
| 474 | /* Sum of the length of all control messages in the buffer: */ |
| 475 | msg.msg_controllen = cmptr->cmsg_len; |
| 476 | |
| 477 | iov[0].iov_base = &dummy; |
| 478 | iov[0].iov_len = 1; |
| 479 | msg.msg_iov = iov; |
| 480 | msg.msg_iovlen = 1; |
| 481 | |
| 482 | retry: |
| 483 | ret = sendmsg(sock, &msg, 0); |
| 484 | if (ret < 0) { |
| 485 | if (errno == EINTR) { |
| 486 | goto retry; |
| 487 | } else { |
| 488 | /* |
| 489 | * We consider EPIPE and EAGAIN/EWOULDBLOCK as expected. |
| 490 | */ |
| 491 | if (errno == EAGAIN || errno == EWOULDBLOCK) { |
| 492 | /* |
| 493 | * This can happen in non blocking mode. |
| 494 | * Nothing was sent. |
| 495 | */ |
| 496 | ret = 0; |
| 497 | goto end; |
| 498 | } |
| 499 | |
| 500 | if (errno == EPIPE) { |
| 501 | /* Expected error, pass error to caller */ |
| 502 | DBG3("EPIPE on sendmsg"); |
| 503 | ret = -1; |
| 504 | goto end; |
| 505 | } |
| 506 | |
| 507 | /* Unexpected error */ |
| 508 | PERROR("sendmsg"); |
| 509 | ret = -1; |
| 510 | goto end; |
| 511 | } |
| 512 | } |
| 513 | |
| 514 | end: |
| 515 | return ret; |
| 516 | } |
| 517 | |
| 518 | /* |
| 519 | * Recv a message accompanied by fd(s) from a unix socket. |
| 520 | * |
| 521 | * Returns the size of received data, or negative error value. |
| 522 | * |
| 523 | * Expect at most "nb_fd" file descriptors. Returns the number of fd |
| 524 | * actually received in nb_fd. |
| 525 | */ |
| 526 | LTTNG_HIDDEN |
| 527 | ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd) |
| 528 | { |
| 529 | struct iovec iov[1]; |
| 530 | ssize_t ret = 0; |
| 531 | struct cmsghdr *cmsg; |
| 532 | size_t sizeof_fds = nb_fd * sizeof(int); |
| 533 | |
| 534 | #ifdef __linux__ |
| 535 | /* Account for the struct ucred cmsg in the buffer size */ |
| 536 | #define LTTNG_SOCK_RECV_FDS_BUF_SIZE CMSG_SPACE(sizeof_fds) + CMSG_SPACE(sizeof(struct ucred)) |
| 537 | #else |
| 538 | #define LTTNG_SOCK_RECV_FDS_BUF_SIZE CMSG_SPACE(sizeof_fds) |
| 539 | #endif /* __linux__ */ |
| 540 | |
| 541 | char recv_buf[LTTNG_SOCK_RECV_FDS_BUF_SIZE]; |
| 542 | struct msghdr msg; |
| 543 | char dummy; |
| 544 | |
| 545 | memset(&msg, 0, sizeof(msg)); |
| 546 | |
| 547 | /* Prepare to receive the structures */ |
| 548 | iov[0].iov_base = &dummy; |
| 549 | iov[0].iov_len = 1; |
| 550 | msg.msg_iov = iov; |
| 551 | msg.msg_iovlen = 1; |
| 552 | |
| 553 | cmsg = (struct cmsghdr *) recv_buf; |
| 554 | cmsg->cmsg_len = CMSG_LEN(sizeof_fds); |
| 555 | cmsg->cmsg_level = SOL_SOCKET; |
| 556 | cmsg->cmsg_type = SCM_RIGHTS; |
| 557 | |
| 558 | msg.msg_control = cmsg; |
| 559 | msg.msg_controllen = CMSG_LEN(sizeof(recv_buf)); |
| 560 | msg.msg_flags = 0; |
| 561 | |
| 562 | retry: |
| 563 | ret = lttng_recvmsg_nosigpipe(sock, &msg); |
| 564 | if (ret < 0) { |
| 565 | if (errno == EINTR) { |
| 566 | goto retry; |
| 567 | } else { |
| 568 | /* We consider EPIPE and EAGAIN as expected. */ |
| 569 | if (!lttng_opt_quiet && |
| 570 | (errno != EPIPE && errno != EAGAIN)) { |
| 571 | PERROR("recvmsg"); |
| 572 | } |
| 573 | goto end; |
| 574 | } |
| 575 | } |
| 576 | |
| 577 | if (ret != 1) { |
| 578 | fprintf(stderr, "Error: Received %zd bytes, expected %d\n", |
| 579 | ret, 1); |
| 580 | goto end; |
| 581 | } |
| 582 | |
| 583 | if (msg.msg_flags & MSG_CTRUNC) { |
| 584 | fprintf(stderr, "Error: Control message truncated.\n"); |
| 585 | ret = -1; |
| 586 | goto end; |
| 587 | } |
| 588 | |
| 589 | /* |
| 590 | * If the socket was configured with SO_PASSCRED, the kernel will add a |
| 591 | * control message (cmsg) to the ancillary data of the unix socket. We |
| 592 | * need to expect a cmsg of the SCM_CREDENTIALS as the first control |
| 593 | * message. |
| 594 | */ |
| 595 | for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) { |
| 596 | if (cmsg->cmsg_level != SOL_SOCKET) { |
| 597 | fprintf(stderr, "Error: The socket needs to be of type SOL_SOCKET\n"); |
| 598 | ret = -1; |
| 599 | goto end; |
| 600 | } |
| 601 | if (cmsg->cmsg_type == SCM_RIGHTS) { |
| 602 | /* |
| 603 | * We found the controle message for file descriptors, |
| 604 | * now copy the fds to the fds ptr and return success. |
| 605 | */ |
| 606 | if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) { |
| 607 | fprintf(stderr, "Error: Received %zu bytes of" |
| 608 | "ancillary data for FDs, expected %zu\n", |
| 609 | (size_t) cmsg->cmsg_len, |
| 610 | (size_t) CMSG_LEN(sizeof_fds)); |
| 611 | ret = -1; |
| 612 | goto end; |
| 613 | } |
| 614 | memcpy(fds, CMSG_DATA(cmsg), sizeof_fds); |
| 615 | ret = sizeof_fds; |
| 616 | goto end; |
| 617 | } |
| 618 | #ifdef __linux__ |
| 619 | if (cmsg->cmsg_type == SCM_CREDENTIALS) { |
| 620 | /* |
| 621 | * Expect credentials to be sent when expecting fds even |
| 622 | * if no credential were include in the send(). The |
| 623 | * kernel adds them... |
| 624 | */ |
| 625 | ret = -1; |
| 626 | } |
| 627 | #endif /* __linux__ */ |
| 628 | } |
| 629 | end: |
| 630 | return ret; |
| 631 | } |
| 632 | |
| 633 | /* |
| 634 | * Recv a message accompanied by fd(s) from a non-blocking unix socket. |
| 635 | * Only use with non-blocking sockets. |
| 636 | * |
| 637 | * Returns the size of received data, or negative error value. |
| 638 | * |
| 639 | * Expect at most "nb_fd" file descriptors. |
| 640 | * |
| 641 | * Note that based on our comprehension, partial reception of fds is not |
| 642 | * possible since the FDs are actually in the control message. It is all or |
| 643 | * nothing, still the sender side can send the wrong number of fds. |
| 644 | */ |
| 645 | LTTNG_HIDDEN |
| 646 | ssize_t lttcomm_recv_fds_unix_sock_non_block(int sock, int *fds, size_t nb_fd) |
| 647 | { |
| 648 | struct iovec iov[1]; |
| 649 | ssize_t ret = 0; |
| 650 | struct cmsghdr *cmsg; |
| 651 | size_t sizeof_fds = nb_fd * sizeof(int); |
| 652 | |
| 653 | #ifdef __linux__ |
| 654 | /* Account for the struct ucred cmsg in the buffer size */ |
| 655 | #define LTTNG_SOCK_RECV_FDS_BUF_SIZE CMSG_SPACE(sizeof_fds) + CMSG_SPACE(sizeof(struct ucred)) |
| 656 | #else |
| 657 | #define LTTNG_SOCK_RECV_FDS_BUF_SIZE CMSG_SPACE(sizeof_fds) |
| 658 | #endif /* __linux__ */ |
| 659 | |
| 660 | char recv_buf[LTTNG_SOCK_RECV_FDS_BUF_SIZE]; |
| 661 | struct msghdr msg; |
| 662 | char dummy; |
| 663 | |
| 664 | memset(&msg, 0, sizeof(msg)); |
| 665 | |
| 666 | /* Prepare to receive the structures */ |
| 667 | iov[0].iov_base = &dummy; |
| 668 | iov[0].iov_len = 1; |
| 669 | msg.msg_iov = iov; |
| 670 | msg.msg_iovlen = 1; |
| 671 | |
| 672 | cmsg = (struct cmsghdr *) recv_buf; |
| 673 | cmsg->cmsg_len = CMSG_LEN(sizeof_fds); |
| 674 | cmsg->cmsg_level = SOL_SOCKET; |
| 675 | cmsg->cmsg_type = SCM_RIGHTS; |
| 676 | |
| 677 | msg.msg_control = cmsg; |
| 678 | msg.msg_controllen = CMSG_LEN(sizeof(recv_buf)); |
| 679 | msg.msg_flags = 0; |
| 680 | |
| 681 | retry: |
| 682 | ret = lttng_recvmsg_nosigpipe(sock, &msg); |
| 683 | if (ret < 0) { |
| 684 | if (errno == EINTR) { |
| 685 | goto retry; |
| 686 | } else { |
| 687 | /* |
| 688 | * We consider EPIPE and EAGAIN/EWOULDBLOCK as expected. |
| 689 | */ |
| 690 | if (errno == EAGAIN || errno == EWOULDBLOCK) { |
| 691 | /* |
| 692 | * This can happen in non blocking mode. |
| 693 | * Nothing was recv. |
| 694 | */ |
| 695 | ret = 0; |
| 696 | goto end; |
| 697 | } |
| 698 | |
| 699 | if (errno == EPIPE) { |
| 700 | /* Expected error, pass error to caller */ |
| 701 | DBG3("EPIPE on recvmsg"); |
| 702 | ret = -1; |
| 703 | goto end; |
| 704 | } |
| 705 | |
| 706 | /* Unexpected error */ |
| 707 | PERROR("recvmsg"); |
| 708 | ret = -1; |
| 709 | goto end; |
| 710 | } |
| 711 | } |
| 712 | |
| 713 | if (ret != 1) { |
| 714 | fprintf(stderr, "Error: Received %zd bytes, expected %d\n", |
| 715 | ret, 1); |
| 716 | goto end; |
| 717 | } |
| 718 | |
| 719 | if (msg.msg_flags & MSG_CTRUNC) { |
| 720 | fprintf(stderr, "Error: Control message truncated.\n"); |
| 721 | ret = -1; |
| 722 | goto end; |
| 723 | } |
| 724 | |
| 725 | /* |
| 726 | * If the socket was configured with SO_PASSCRED, the kernel will add a |
| 727 | * control message (cmsg) to the ancillary data of the unix socket. We |
| 728 | * need to expect a cmsg of the SCM_CREDENTIALS as the first control |
| 729 | * message. |
| 730 | */ |
| 731 | for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) { |
| 732 | if (cmsg->cmsg_level != SOL_SOCKET) { |
| 733 | fprintf(stderr, "Error: The socket needs to be of type SOL_SOCKET\n"); |
| 734 | ret = -1; |
| 735 | goto end; |
| 736 | } |
| 737 | if (cmsg->cmsg_type == SCM_RIGHTS) { |
| 738 | /* |
| 739 | * We found the controle message for file descriptors, |
| 740 | * now copy the fds to the fds ptr and return success. |
| 741 | */ |
| 742 | if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) { |
| 743 | fprintf(stderr, "Error: Received %zu bytes of" |
| 744 | "ancillary data for FDs, expected %zu\n", |
| 745 | (size_t) cmsg->cmsg_len, |
| 746 | (size_t) CMSG_LEN(sizeof_fds)); |
| 747 | ret = -1; |
| 748 | goto end; |
| 749 | } |
| 750 | memcpy(fds, CMSG_DATA(cmsg), sizeof_fds); |
| 751 | ret = sizeof_fds; |
| 752 | goto end; |
| 753 | } |
| 754 | #ifdef __linux__ |
| 755 | if (cmsg->cmsg_type == SCM_CREDENTIALS) { |
| 756 | /* |
| 757 | * Expect credentials to be sent when expecting fds even |
| 758 | * if no credential were include in the send(). The |
| 759 | * kernel adds them... |
| 760 | */ |
| 761 | ret = -1; |
| 762 | } |
| 763 | #endif /* __linux__ */ |
| 764 | } |
| 765 | end: |
| 766 | return ret; |
| 767 | } |
| 768 | |
| 769 | /* |
| 770 | * Send a message with credentials over a unix socket. |
| 771 | * |
| 772 | * Returns the size of data sent, or negative error value. |
| 773 | */ |
| 774 | LTTNG_HIDDEN |
| 775 | ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len) |
| 776 | { |
| 777 | struct msghdr msg; |
| 778 | struct iovec iov[1]; |
| 779 | ssize_t ret = -1; |
| 780 | #ifdef __linux__ |
| 781 | struct cmsghdr *cmptr; |
| 782 | size_t sizeof_cred = sizeof(lttng_sock_cred); |
| 783 | char anc_buf[CMSG_SPACE(sizeof_cred)]; |
| 784 | lttng_sock_cred *creds; |
| 785 | |
| 786 | memset(anc_buf, 0, CMSG_SPACE(sizeof_cred) * sizeof(char)); |
| 787 | #endif /* __linux__ */ |
| 788 | |
| 789 | memset(&msg, 0, sizeof(msg)); |
| 790 | |
| 791 | iov[0].iov_base = buf; |
| 792 | iov[0].iov_len = len; |
| 793 | msg.msg_iov = iov; |
| 794 | msg.msg_iovlen = 1; |
| 795 | |
| 796 | #ifdef __linux__ |
| 797 | msg.msg_control = (caddr_t) anc_buf; |
| 798 | msg.msg_controllen = CMSG_LEN(sizeof_cred); |
| 799 | |
| 800 | cmptr = CMSG_FIRSTHDR(&msg); |
| 801 | if (!cmptr) { |
| 802 | return -1; |
| 803 | } |
| 804 | cmptr->cmsg_level = SOL_SOCKET; |
| 805 | cmptr->cmsg_type = LTTNG_SOCK_CREDS; |
| 806 | cmptr->cmsg_len = CMSG_LEN(sizeof_cred); |
| 807 | |
| 808 | creds = (lttng_sock_cred*) CMSG_DATA(cmptr); |
| 809 | |
| 810 | LTTNG_SOCK_SET_UID_CRED(creds, geteuid()); |
| 811 | LTTNG_SOCK_SET_GID_CRED(creds, getegid()); |
| 812 | LTTNG_SOCK_SET_PID_CRED(creds, getpid()); |
| 813 | #endif /* __linux__ */ |
| 814 | |
| 815 | do { |
| 816 | ret = sendmsg(sock, &msg, 0); |
| 817 | } while (ret < 0 && errno == EINTR); |
| 818 | if (ret < 0) { |
| 819 | /* |
| 820 | * Only warn about EPIPE when quiet mode is deactivated. |
| 821 | * We consider EPIPE as expected. |
| 822 | */ |
| 823 | if (errno != EPIPE || !lttng_opt_quiet) { |
| 824 | PERROR("sendmsg"); |
| 825 | } |
| 826 | } |
| 827 | return ret; |
| 828 | } |
| 829 | |
| 830 | /* |
| 831 | * Recv a message accompanied with credentials from a unix socket. |
| 832 | * |
| 833 | * Returns the size of received data, or negative error value. |
| 834 | */ |
| 835 | LTTNG_HIDDEN |
| 836 | ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len, |
| 837 | lttng_sock_cred *creds) |
| 838 | { |
| 839 | struct msghdr msg; |
| 840 | struct iovec iov[1]; |
| 841 | ssize_t ret; |
| 842 | size_t len_last; |
| 843 | #ifdef __linux__ |
| 844 | struct cmsghdr *cmptr; |
| 845 | size_t sizeof_cred = sizeof(lttng_sock_cred); |
| 846 | char anc_buf[CMSG_SPACE(sizeof_cred)]; |
| 847 | #endif /* __linux__ */ |
| 848 | |
| 849 | memset(&msg, 0, sizeof(msg)); |
| 850 | |
| 851 | /* Not allowed */ |
| 852 | if (creds == NULL) { |
| 853 | ret = -1; |
| 854 | goto end; |
| 855 | } |
| 856 | |
| 857 | /* Prepare to receive the structures */ |
| 858 | iov[0].iov_base = buf; |
| 859 | iov[0].iov_len = len; |
| 860 | msg.msg_iov = iov; |
| 861 | msg.msg_iovlen = 1; |
| 862 | |
| 863 | #ifdef __linux__ |
| 864 | msg.msg_control = anc_buf; |
| 865 | msg.msg_controllen = sizeof(anc_buf); |
| 866 | #endif /* __linux__ */ |
| 867 | |
| 868 | do { |
| 869 | len_last = iov[0].iov_len; |
| 870 | ret = recvmsg(sock, &msg, 0); |
| 871 | if (ret > 0) { |
| 872 | iov[0].iov_base += ret; |
| 873 | iov[0].iov_len -= ret; |
| 874 | assert(ret <= len_last); |
| 875 | } |
| 876 | } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR)); |
| 877 | if (ret < 0) { |
| 878 | PERROR("recvmsg fds"); |
| 879 | goto end; |
| 880 | } else if (ret > 0) { |
| 881 | ret = len; |
| 882 | } |
| 883 | /* Else ret = 0 meaning an orderly shutdown. */ |
| 884 | |
| 885 | #ifdef __linux__ |
| 886 | if (msg.msg_flags & MSG_CTRUNC) { |
| 887 | fprintf(stderr, "Error: Control message truncated.\n"); |
| 888 | ret = -1; |
| 889 | goto end; |
| 890 | } |
| 891 | |
| 892 | cmptr = CMSG_FIRSTHDR(&msg); |
| 893 | if (cmptr == NULL) { |
| 894 | fprintf(stderr, "Error: Invalid control message header\n"); |
| 895 | ret = -1; |
| 896 | goto end; |
| 897 | } |
| 898 | |
| 899 | if (cmptr->cmsg_level != SOL_SOCKET || |
| 900 | cmptr->cmsg_type != LTTNG_SOCK_CREDS) { |
| 901 | fprintf(stderr, "Didn't received any credentials\n"); |
| 902 | ret = -1; |
| 903 | goto end; |
| 904 | } |
| 905 | |
| 906 | if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) { |
| 907 | fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n", |
| 908 | (size_t) cmptr->cmsg_len, (size_t) CMSG_LEN(sizeof_cred)); |
| 909 | ret = -1; |
| 910 | goto end; |
| 911 | } |
| 912 | |
| 913 | memcpy(creds, CMSG_DATA(cmptr), sizeof_cred); |
| 914 | #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__)) |
| 915 | { |
| 916 | int peer_ret; |
| 917 | |
| 918 | peer_ret = getpeereid(sock, &creds->uid, &creds->gid); |
| 919 | if (peer_ret != 0) { |
| 920 | return peer_ret; |
| 921 | } |
| 922 | } |
| 923 | #else |
| 924 | #error "Please implement credential support for your OS." |
| 925 | #endif /* __linux__ */ |
| 926 | |
| 927 | end: |
| 928 | return ret; |
| 929 | } |
| 930 | |
| 931 | /* |
| 932 | * Set socket option to use credentials passing. |
| 933 | */ |
| 934 | #ifdef __linux__ |
| 935 | LTTNG_HIDDEN |
| 936 | int lttcomm_setsockopt_creds_unix_sock(int sock) |
| 937 | { |
| 938 | int ret, on = 1; |
| 939 | |
| 940 | /* Set socket for credentials retrieval */ |
| 941 | ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)); |
| 942 | if (ret < 0) { |
| 943 | PERROR("setsockopt creds unix sock"); |
| 944 | } |
| 945 | return ret; |
| 946 | } |
| 947 | #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__)) |
| 948 | LTTNG_HIDDEN |
| 949 | int lttcomm_setsockopt_creds_unix_sock(int sock) |
| 950 | { |
| 951 | return 0; |
| 952 | } |
| 953 | #else |
| 954 | #error "Please implement credential support for your OS." |
| 955 | #endif /* __linux__ */ |