| 1 | /* |
| 2 | * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca> |
| 3 | * Copyright (C) 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 4 | * |
| 5 | * This library is free software; you can redistribute it and/or |
| 6 | * modify it under the terms of the GNU Lesser General Public |
| 7 | * License as published by the Free Software Foundation; only |
| 8 | * version 2.1 of the License. |
| 9 | * |
| 10 | * This library is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | * Lesser General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU Lesser General Public |
| 16 | * License along with this library; if not, write to the Free Software |
| 17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 18 | */ |
| 19 | |
| 20 | #define _GNU_SOURCE |
| 21 | #include <limits.h> |
| 22 | #include <stdio.h> |
| 23 | #include <stdlib.h> |
| 24 | #include <string.h> |
| 25 | #include <sys/socket.h> |
| 26 | #include <sys/stat.h> |
| 27 | #include <sys/types.h> |
| 28 | #include <sys/un.h> |
| 29 | #include <unistd.h> |
| 30 | #include <assert.h> |
| 31 | #include <errno.h> |
| 32 | #include <fcntl.h> |
| 33 | |
| 34 | #include <ust-comm.h> |
| 35 | #include <lttng/ust-error.h> |
| 36 | |
| 37 | #define USTCOMM_CODE_OFFSET(code) \ |
| 38 | (code == LTTNG_UST_OK ? 0 : (code - LTTNG_UST_ERR + 1)) |
| 39 | |
| 40 | /* |
| 41 | * Human readable error message. |
| 42 | */ |
| 43 | static const char *ustcomm_readable_code[] = { |
| 44 | [ USTCOMM_CODE_OFFSET(LTTNG_UST_OK) ] = "Success", |
| 45 | [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR) ] = "Unknown error", |
| 46 | [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_NOENT) ] = "No entry", |
| 47 | [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_EXIST) ] = "Object already exists", |
| 48 | [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_INVAL) ] = "Invalid argument", |
| 49 | [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_PERM) ] = "Permission denied", |
| 50 | [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_NOSYS) ] = "Not implemented", |
| 51 | }; |
| 52 | |
| 53 | /* |
| 54 | * lttng_ust_strerror |
| 55 | * |
| 56 | * Receives positive error value. |
| 57 | * Return ptr to string representing a human readable |
| 58 | * error code from the ustcomm_return_code enum. |
| 59 | */ |
| 60 | const char *lttng_ust_strerror(int code) |
| 61 | { |
| 62 | if (code == LTTNG_UST_OK) |
| 63 | return ustcomm_readable_code[USTCOMM_CODE_OFFSET(code)]; |
| 64 | if (code < LTTNG_UST_ERR) |
| 65 | return strerror(code); |
| 66 | if (code >= LTTNG_UST_ERR_NR) |
| 67 | code = LTTNG_UST_ERR; |
| 68 | return ustcomm_readable_code[USTCOMM_CODE_OFFSET(code)]; |
| 69 | |
| 70 | } |
| 71 | |
| 72 | /* |
| 73 | * ustcomm_connect_unix_sock |
| 74 | * |
| 75 | * Connect to unix socket using the path name. |
| 76 | */ |
| 77 | int ustcomm_connect_unix_sock(const char *pathname) |
| 78 | { |
| 79 | struct sockaddr_un sun; |
| 80 | int fd, ret; |
| 81 | |
| 82 | /* |
| 83 | * libust threads require the close-on-exec flag for all |
| 84 | * resources so it does not leak file descriptors upon exec. |
| 85 | */ |
| 86 | fd = socket(PF_UNIX, SOCK_STREAM, 0); |
| 87 | if (fd < 0) { |
| 88 | perror("socket"); |
| 89 | ret = -errno; |
| 90 | goto error; |
| 91 | } |
| 92 | ret = fcntl(fd, F_SETFD, FD_CLOEXEC); |
| 93 | if (ret < 0) { |
| 94 | perror("fcntl"); |
| 95 | ret = -errno; |
| 96 | goto error_fcntl; |
| 97 | } |
| 98 | |
| 99 | memset(&sun, 0, sizeof(sun)); |
| 100 | sun.sun_family = AF_UNIX; |
| 101 | strncpy(sun.sun_path, pathname, sizeof(sun.sun_path)); |
| 102 | sun.sun_path[sizeof(sun.sun_path) - 1] = '\0'; |
| 103 | |
| 104 | ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun)); |
| 105 | if (ret < 0) { |
| 106 | /* |
| 107 | * Don't print message on connect error, because connect |
| 108 | * is used in normal execution to detect if sessiond is |
| 109 | * alive. |
| 110 | */ |
| 111 | ret = -errno; |
| 112 | goto error_connect; |
| 113 | } |
| 114 | |
| 115 | return fd; |
| 116 | |
| 117 | error_connect: |
| 118 | error_fcntl: |
| 119 | { |
| 120 | int closeret; |
| 121 | |
| 122 | closeret = close(fd); |
| 123 | if (closeret) |
| 124 | perror("close"); |
| 125 | } |
| 126 | error: |
| 127 | return ret; |
| 128 | } |
| 129 | |
| 130 | /* |
| 131 | * ustcomm_accept_unix_sock |
| 132 | * |
| 133 | * Do an accept(2) on the sock and return the |
| 134 | * new file descriptor. The socket MUST be bind(2) before. |
| 135 | */ |
| 136 | int ustcomm_accept_unix_sock(int sock) |
| 137 | { |
| 138 | int new_fd; |
| 139 | struct sockaddr_un sun; |
| 140 | socklen_t len = 0; |
| 141 | |
| 142 | /* Blocking call */ |
| 143 | new_fd = accept(sock, (struct sockaddr *) &sun, &len); |
| 144 | if (new_fd < 0) { |
| 145 | perror("accept"); |
| 146 | return -errno; |
| 147 | } |
| 148 | return new_fd; |
| 149 | } |
| 150 | |
| 151 | /* |
| 152 | * ustcomm_create_unix_sock |
| 153 | * |
| 154 | * Creates a AF_UNIX local socket using pathname |
| 155 | * bind the socket upon creation and return the fd. |
| 156 | */ |
| 157 | int ustcomm_create_unix_sock(const char *pathname) |
| 158 | { |
| 159 | struct sockaddr_un sun; |
| 160 | int fd, ret; |
| 161 | |
| 162 | /* Create server socket */ |
| 163 | if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) { |
| 164 | perror("socket"); |
| 165 | ret = -errno; |
| 166 | goto error; |
| 167 | } |
| 168 | |
| 169 | memset(&sun, 0, sizeof(sun)); |
| 170 | sun.sun_family = AF_UNIX; |
| 171 | strncpy(sun.sun_path, pathname, sizeof(sun.sun_path)); |
| 172 | sun.sun_path[sizeof(sun.sun_path) - 1] = '\0'; |
| 173 | |
| 174 | /* Unlink the old file if present */ |
| 175 | (void) unlink(pathname); |
| 176 | ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun)); |
| 177 | if (ret < 0) { |
| 178 | perror("bind"); |
| 179 | ret = -errno; |
| 180 | goto error_close; |
| 181 | } |
| 182 | |
| 183 | return fd; |
| 184 | |
| 185 | error_close: |
| 186 | { |
| 187 | int closeret; |
| 188 | |
| 189 | closeret = close(fd); |
| 190 | if (closeret) { |
| 191 | perror("close"); |
| 192 | } |
| 193 | } |
| 194 | error: |
| 195 | return ret; |
| 196 | } |
| 197 | |
| 198 | /* |
| 199 | * ustcomm_listen_unix_sock |
| 200 | * |
| 201 | * Make the socket listen using LTTNG_UST_COMM_MAX_LISTEN. |
| 202 | */ |
| 203 | int ustcomm_listen_unix_sock(int sock) |
| 204 | { |
| 205 | int ret; |
| 206 | |
| 207 | ret = listen(sock, LTTNG_UST_COMM_MAX_LISTEN); |
| 208 | if (ret < 0) { |
| 209 | ret = -errno; |
| 210 | perror("listen"); |
| 211 | } |
| 212 | |
| 213 | return ret; |
| 214 | } |
| 215 | |
| 216 | /* |
| 217 | * ustcomm_recv_unix_sock |
| 218 | * |
| 219 | * Receive data of size len in put that data into |
| 220 | * the buf param. Using recvmsg API. |
| 221 | * Return the size of received data. |
| 222 | */ |
| 223 | ssize_t ustcomm_recv_unix_sock(int sock, void *buf, size_t len) |
| 224 | { |
| 225 | struct msghdr msg; |
| 226 | struct iovec iov[1]; |
| 227 | ssize_t ret; |
| 228 | |
| 229 | memset(&msg, 0, sizeof(msg)); |
| 230 | |
| 231 | iov[0].iov_base = buf; |
| 232 | iov[0].iov_len = len; |
| 233 | msg.msg_iov = iov; |
| 234 | msg.msg_iovlen = 1; |
| 235 | |
| 236 | do { |
| 237 | ret = recvmsg(sock, &msg, 0); |
| 238 | } while (ret < 0 && errno == EINTR); |
| 239 | |
| 240 | if (ret < 0) { |
| 241 | int shutret; |
| 242 | |
| 243 | if (errno != EPIPE) |
| 244 | perror("recvmsg"); |
| 245 | ret = -errno; |
| 246 | |
| 247 | shutret = shutdown(sock, SHUT_RDWR); |
| 248 | if (shutret) |
| 249 | fprintf(stderr, "Socket shutdown error"); |
| 250 | } |
| 251 | |
| 252 | return ret; |
| 253 | } |
| 254 | |
| 255 | /* |
| 256 | * ustcomm_send_unix_sock |
| 257 | * |
| 258 | * Send buf data of size len. Using sendmsg API. |
| 259 | * Return the size of sent data. |
| 260 | */ |
| 261 | ssize_t ustcomm_send_unix_sock(int sock, void *buf, size_t len) |
| 262 | { |
| 263 | struct msghdr msg; |
| 264 | struct iovec iov[1]; |
| 265 | ssize_t ret; |
| 266 | |
| 267 | memset(&msg, 0, sizeof(msg)); |
| 268 | |
| 269 | iov[0].iov_base = buf; |
| 270 | iov[0].iov_len = len; |
| 271 | msg.msg_iov = iov; |
| 272 | msg.msg_iovlen = 1; |
| 273 | |
| 274 | /* |
| 275 | * Using the MSG_NOSIGNAL when sending data from sessiond to |
| 276 | * libust, so libust does not receive an unhandled SIGPIPE or |
| 277 | * SIGURG. The sessiond receiver side can be made more resilient |
| 278 | * by ignoring SIGPIPE, but we don't have this luxury on the |
| 279 | * libust side. |
| 280 | */ |
| 281 | do { |
| 282 | ret = sendmsg(sock, &msg, MSG_NOSIGNAL); |
| 283 | } while (ret < 0 && errno == EINTR); |
| 284 | |
| 285 | if (ret < 0) { |
| 286 | int shutret; |
| 287 | |
| 288 | if (errno != EPIPE) |
| 289 | perror("recvmsg"); |
| 290 | ret = -errno; |
| 291 | |
| 292 | shutret = shutdown(sock, SHUT_RDWR); |
| 293 | if (shutret) |
| 294 | fprintf(stderr, "Socket shutdown error"); |
| 295 | } |
| 296 | |
| 297 | return ret; |
| 298 | } |
| 299 | |
| 300 | /* |
| 301 | * ustcomm_close_unix_sock |
| 302 | * |
| 303 | * Shutdown cleanly a unix socket. |
| 304 | */ |
| 305 | int ustcomm_close_unix_sock(int sock) |
| 306 | { |
| 307 | int ret; |
| 308 | |
| 309 | ret = close(sock); |
| 310 | if (ret < 0) { |
| 311 | perror("close"); |
| 312 | ret = -errno; |
| 313 | } |
| 314 | |
| 315 | return ret; |
| 316 | } |
| 317 | |
| 318 | /* |
| 319 | * ustcomm_send_fds_unix_sock |
| 320 | * |
| 321 | * Send multiple fds on a unix socket. |
| 322 | */ |
| 323 | ssize_t ustcomm_send_fds_unix_sock(int sock, void *buf, int *fds, size_t nb_fd, size_t len) |
| 324 | { |
| 325 | struct msghdr msg; |
| 326 | struct cmsghdr *cmptr; |
| 327 | struct iovec iov[1]; |
| 328 | ssize_t ret = -1; |
| 329 | unsigned int sizeof_fds = nb_fd * sizeof(int); |
| 330 | char tmp[CMSG_SPACE(sizeof_fds)]; |
| 331 | |
| 332 | memset(&msg, 0, sizeof(msg)); |
| 333 | |
| 334 | /* |
| 335 | * Note: we currently only support sending a single FD per |
| 336 | * message. |
| 337 | */ |
| 338 | assert(nb_fd == 1); |
| 339 | |
| 340 | msg.msg_control = (caddr_t)tmp; |
| 341 | msg.msg_controllen = CMSG_LEN(sizeof_fds); |
| 342 | |
| 343 | cmptr = CMSG_FIRSTHDR(&msg); |
| 344 | cmptr->cmsg_level = SOL_SOCKET; |
| 345 | cmptr->cmsg_type = SCM_RIGHTS; |
| 346 | cmptr->cmsg_len = CMSG_LEN(sizeof_fds); |
| 347 | memcpy(CMSG_DATA(cmptr), fds, sizeof_fds); |
| 348 | /* Sum of the length of all control messages in the buffer: */ |
| 349 | msg.msg_controllen = cmptr->cmsg_len; |
| 350 | |
| 351 | iov[0].iov_base = buf; |
| 352 | iov[0].iov_len = len; |
| 353 | msg.msg_iov = iov; |
| 354 | msg.msg_iovlen = 1; |
| 355 | |
| 356 | do { |
| 357 | ret = sendmsg(sock, &msg, MSG_NOSIGNAL); |
| 358 | } while (ret < 0 && errno == EINTR); |
| 359 | |
| 360 | if (ret < 0) { |
| 361 | int shutret; |
| 362 | |
| 363 | if (errno != EPIPE) |
| 364 | perror("recvmsg"); |
| 365 | ret = -errno; |
| 366 | |
| 367 | shutret = shutdown(sock, SHUT_RDWR); |
| 368 | if (shutret) |
| 369 | fprintf(stderr, "Socket shutdown error"); |
| 370 | } |
| 371 | |
| 372 | return ret; |
| 373 | } |
| 374 | |
| 375 | int ustcomm_send_app_msg(int sock, struct ustcomm_ust_msg *lum) |
| 376 | { |
| 377 | ssize_t len; |
| 378 | |
| 379 | len = ustcomm_send_unix_sock(sock, lum, sizeof(*lum)); |
| 380 | switch (len) { |
| 381 | case sizeof(*lum): |
| 382 | break; |
| 383 | default: |
| 384 | if (len < 0) { |
| 385 | if (len == -ECONNRESET) |
| 386 | fprintf(stderr, "remote end closed connection\n"); |
| 387 | return len; |
| 388 | } else { |
| 389 | fprintf(stderr, "incorrect message size: %zd\n", len); |
| 390 | return -EINVAL; |
| 391 | } |
| 392 | } |
| 393 | return 0; |
| 394 | } |
| 395 | |
| 396 | int ustcomm_recv_app_reply(int sock, struct ustcomm_ust_reply *lur, |
| 397 | uint32_t expected_handle, uint32_t expected_cmd) |
| 398 | { |
| 399 | ssize_t len; |
| 400 | |
| 401 | memset(lur, 0, sizeof(*lur)); |
| 402 | len = ustcomm_recv_unix_sock(sock, lur, sizeof(*lur)); |
| 403 | switch (len) { |
| 404 | case 0: /* orderly shutdown */ |
| 405 | return -EINVAL; |
| 406 | case sizeof(*lur): |
| 407 | if (lur->handle != expected_handle) { |
| 408 | fprintf(stderr, "Unexpected result message handle\n"); |
| 409 | return -EINVAL; |
| 410 | } |
| 411 | if (lur->cmd != expected_cmd) { |
| 412 | fprintf(stderr, "Unexpected result message command\n"); |
| 413 | return -EINVAL; |
| 414 | } |
| 415 | return lur->ret_code; |
| 416 | default: |
| 417 | if (len < 0) { |
| 418 | /* Transport level error */ |
| 419 | if (len == -ECONNRESET) |
| 420 | fprintf(stderr, "remote end closed connection\n"); |
| 421 | return len; |
| 422 | } else { |
| 423 | fprintf(stderr, "incorrect message size: %zd\n", len); |
| 424 | return len; |
| 425 | } |
| 426 | } |
| 427 | } |
| 428 | |
| 429 | int ustcomm_send_app_cmd(int sock, |
| 430 | struct ustcomm_ust_msg *lum, |
| 431 | struct ustcomm_ust_reply *lur) |
| 432 | { |
| 433 | int ret; |
| 434 | |
| 435 | ret = ustcomm_send_app_msg(sock, lum); |
| 436 | if (ret) |
| 437 | return ret; |
| 438 | ret = ustcomm_recv_app_reply(sock, lur, lum->handle, lum->cmd); |
| 439 | if (ret > 0) |
| 440 | return -EIO; |
| 441 | return ret; |
| 442 | } |
| 443 | |
| 444 | /* |
| 445 | * Receives a single fd from socket. |
| 446 | * |
| 447 | * Returns negative error value on error, or file descriptor number on |
| 448 | * success. |
| 449 | */ |
| 450 | int ustcomm_recv_fd(int sock) |
| 451 | { |
| 452 | struct iovec iov[1]; |
| 453 | int ret = 0; |
| 454 | int data_fd; |
| 455 | struct cmsghdr *cmsg; |
| 456 | char recv_fd[CMSG_SPACE(sizeof(int))]; |
| 457 | struct msghdr msg; |
| 458 | union { |
| 459 | unsigned char vc[4]; |
| 460 | int vi; |
| 461 | } tmp; |
| 462 | int i; |
| 463 | |
| 464 | memset(&msg, 0, sizeof(msg)); |
| 465 | |
| 466 | /* Prepare to receive the structures */ |
| 467 | iov[0].iov_base = &data_fd; |
| 468 | iov[0].iov_len = sizeof(data_fd); |
| 469 | msg.msg_iov = iov; |
| 470 | msg.msg_iovlen = 1; |
| 471 | msg.msg_control = recv_fd; |
| 472 | msg.msg_controllen = sizeof(recv_fd); |
| 473 | |
| 474 | do { |
| 475 | ret = recvmsg(sock, &msg, 0); |
| 476 | } while (ret < 0 && errno == EINTR); |
| 477 | if (ret < 0) { |
| 478 | if (errno != EPIPE) { |
| 479 | perror("recvmsg"); |
| 480 | } |
| 481 | ret = -errno; |
| 482 | goto end; |
| 483 | } |
| 484 | if (ret != sizeof(data_fd)) { |
| 485 | fprintf(stderr, "Received %d bytes, expected %zd", ret, sizeof(data_fd)); |
| 486 | ret = -EINVAL; |
| 487 | goto end; |
| 488 | } |
| 489 | cmsg = CMSG_FIRSTHDR(&msg); |
| 490 | if (!cmsg) { |
| 491 | fprintf(stderr, "Invalid control message header\n"); |
| 492 | ret = -EINVAL; |
| 493 | goto end; |
| 494 | } |
| 495 | if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) { |
| 496 | fprintf(stderr, "Didn't received any fd\n"); |
| 497 | ret = -EINVAL; |
| 498 | goto end; |
| 499 | } |
| 500 | /* this is our fd */ |
| 501 | for (i = 0; i < sizeof(int); i++) |
| 502 | tmp.vc[i] = CMSG_DATA(cmsg)[i]; |
| 503 | ret = tmp.vi; |
| 504 | /* |
| 505 | * Useful for fd leak debug. |
| 506 | * fprintf(stderr, "received fd %d\n", ret); |
| 507 | */ |
| 508 | end: |
| 509 | if (ret < 0) { |
| 510 | int shutret; |
| 511 | |
| 512 | shutret = shutdown(sock, SHUT_RDWR); |
| 513 | if (shutret) |
| 514 | fprintf(stderr, "Socket shutdown error"); |
| 515 | } |
| 516 | return ret; |
| 517 | } |