Samuel Tan | d7ed851 | 2015-08-13 16:11:35 -0700 | [diff] [blame] | 1 | /* |
| 2 | * dhcpcd - DHCP client daemon |
| 3 | * Copyright (c) 2006-2015 Roy Marples <roy@marples.name> |
| 4 | * All rights reserved |
| 5 | |
| 6 | * Redistribution and use in source and binary forms, with or without |
| 7 | * modification, are permitted provided that the following conditions |
| 8 | * are met: |
| 9 | * 1. Redistributions of source code must retain the above copyright |
| 10 | * notice, this list of conditions and the following disclaimer. |
| 11 | * 2. Redistributions in binary form must reproduce the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer in the |
| 13 | * documentation and/or other materials provided with the distribution. |
| 14 | * |
| 15 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
| 16 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 17 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 18 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
| 19 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 20 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 21 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 22 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 23 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 24 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 25 | * SUCH DAMAGE. |
| 26 | */ |
| 27 | |
| 28 | #include <sys/socket.h> |
| 29 | #include <sys/stat.h> |
| 30 | #include <sys/uio.h> |
| 31 | #include <sys/un.h> |
| 32 | |
| 33 | #include <errno.h> |
| 34 | #include <fcntl.h> |
| 35 | #include <stdio.h> |
| 36 | #include <stdlib.h> |
| 37 | #include <string.h> |
| 38 | #include <time.h> |
| 39 | #include <unistd.h> |
| 40 | |
| 41 | #include "config.h" |
| 42 | #include "common.h" |
| 43 | #include "dhcpcd.h" |
| 44 | #include "control.h" |
| 45 | #include "eloop.h" |
| 46 | |
| 47 | #ifndef SUN_LEN |
| 48 | #define SUN_LEN(su) \ |
| 49 | (sizeof(*(su)) - sizeof((su)->sun_path) + strlen((su)->sun_path)) |
| 50 | #endif |
| 51 | |
| 52 | static void |
| 53 | control_queue_purge(struct dhcpcd_ctx *ctx, char *data) |
| 54 | { |
| 55 | int found; |
| 56 | struct fd_list *fp; |
| 57 | struct fd_data *fpd; |
| 58 | |
| 59 | /* If no other fd queue has the same data, free it */ |
| 60 | found = 0; |
| 61 | TAILQ_FOREACH(fp, &ctx->control_fds, next) { |
| 62 | TAILQ_FOREACH(fpd, &fp->queue, next) { |
| 63 | if (fpd->data == data) { |
| 64 | found = 1; |
| 65 | break; |
| 66 | } |
| 67 | } |
| 68 | } |
| 69 | if (!found) |
| 70 | free(data); |
| 71 | } |
| 72 | |
| 73 | static void |
| 74 | control_queue_free(struct fd_list *fd) |
| 75 | { |
| 76 | struct fd_data *fdp; |
| 77 | |
| 78 | while ((fdp = TAILQ_FIRST(&fd->queue))) { |
| 79 | TAILQ_REMOVE(&fd->queue, fdp, next); |
| 80 | if (fdp->freeit) |
| 81 | control_queue_purge(fd->ctx, fdp->data); |
| 82 | free(fdp); |
| 83 | } |
| 84 | while ((fdp = TAILQ_FIRST(&fd->free_queue))) { |
| 85 | TAILQ_REMOVE(&fd->free_queue, fdp, next); |
| 86 | free(fdp); |
| 87 | } |
| 88 | } |
| 89 | |
| 90 | static void |
| 91 | control_delete(struct fd_list *fd) |
| 92 | { |
| 93 | |
| 94 | TAILQ_REMOVE(&fd->ctx->control_fds, fd, next); |
| 95 | eloop_event_delete(fd->ctx->eloop, fd->fd, 0); |
| 96 | close(fd->fd); |
| 97 | control_queue_free(fd); |
| 98 | free(fd); |
| 99 | } |
| 100 | |
| 101 | static void |
| 102 | control_handle_data(void *arg) |
| 103 | { |
| 104 | struct fd_list *fd = arg; |
| 105 | char buffer[1024], *e, *p, *argvp[255], **ap, *a; |
| 106 | ssize_t bytes; |
| 107 | size_t len; |
| 108 | int argc; |
| 109 | |
| 110 | bytes = read(fd->fd, buffer, sizeof(buffer) - 1); |
| 111 | if (bytes == -1 || bytes == 0) { |
| 112 | /* Control was closed or there was an error. |
| 113 | * Remove it from our list. */ |
| 114 | control_delete(fd); |
| 115 | return; |
| 116 | } |
| 117 | buffer[bytes] = '\0'; |
| 118 | p = buffer; |
| 119 | e = buffer + bytes; |
| 120 | |
| 121 | /* Each command is \n terminated |
| 122 | * Each argument is NULL separated */ |
| 123 | while (p < e) { |
| 124 | argc = 0; |
| 125 | ap = argvp; |
| 126 | while (p < e) { |
| 127 | argc++; |
| 128 | if ((size_t)argc >= sizeof(argvp) / sizeof(argvp[0])) { |
| 129 | errno = ENOBUFS; |
| 130 | return; |
| 131 | } |
| 132 | a = *ap++ = p; |
| 133 | len = strlen(p); |
| 134 | p += len + 1; |
| 135 | if (len && a[len - 1] == '\n') { |
| 136 | a[len - 1] = '\0'; |
| 137 | break; |
| 138 | } |
| 139 | } |
| 140 | *ap = NULL; |
| 141 | if (dhcpcd_handleargs(fd->ctx, fd, argc, argvp) == -1) { |
| 142 | logger(fd->ctx, LOG_ERR, |
| 143 | "%s: dhcpcd_handleargs: %m", __func__); |
| 144 | if (errno != EINTR && errno != EAGAIN) { |
| 145 | control_delete(fd); |
| 146 | return; |
| 147 | } |
| 148 | } |
| 149 | } |
| 150 | } |
| 151 | |
| 152 | static void |
| 153 | control_handle1(struct dhcpcd_ctx *ctx, int lfd, unsigned int fd_flags) |
| 154 | { |
| 155 | struct sockaddr_un run; |
| 156 | socklen_t len; |
| 157 | struct fd_list *l; |
| 158 | int fd, flags; |
| 159 | |
| 160 | len = sizeof(run); |
| 161 | if ((fd = accept(lfd, (struct sockaddr *)&run, &len)) == -1) |
| 162 | return; |
| 163 | if ((flags = fcntl(fd, F_GETFD, 0)) == -1 || |
| 164 | fcntl(fd, F_SETFD, flags | FD_CLOEXEC) == -1) |
| 165 | { |
| 166 | close(fd); |
| 167 | return; |
| 168 | } |
| 169 | if ((flags = fcntl(fd, F_GETFL, 0)) == -1 || |
| 170 | fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1) |
| 171 | { |
| 172 | close(fd); |
| 173 | return; |
| 174 | } |
| 175 | l = malloc(sizeof(*l)); |
| 176 | if (l) { |
| 177 | l->ctx = ctx; |
| 178 | l->fd = fd; |
| 179 | l->flags = fd_flags; |
| 180 | TAILQ_INIT(&l->queue); |
| 181 | TAILQ_INIT(&l->free_queue); |
| 182 | TAILQ_INSERT_TAIL(&ctx->control_fds, l, next); |
| 183 | eloop_event_add(ctx->eloop, l->fd, |
| 184 | control_handle_data, l, NULL, NULL); |
| 185 | } else |
| 186 | close(fd); |
| 187 | } |
| 188 | |
| 189 | static void |
| 190 | control_handle(void *arg) |
| 191 | { |
| 192 | struct dhcpcd_ctx *ctx = arg; |
| 193 | |
| 194 | control_handle1(ctx, ctx->control_fd, 0); |
| 195 | } |
| 196 | |
| 197 | static void |
| 198 | control_handle_unpriv(void *arg) |
| 199 | { |
| 200 | struct dhcpcd_ctx *ctx = arg; |
| 201 | |
| 202 | control_handle1(ctx, ctx->control_unpriv_fd, FD_UNPRIV); |
| 203 | } |
| 204 | |
| 205 | static int |
| 206 | make_sock(struct sockaddr_un *sa, const char *ifname, int unpriv) |
| 207 | { |
| 208 | int fd; |
| 209 | |
| 210 | #ifdef SOCK_CLOEXEC |
| 211 | if ((fd = socket(AF_UNIX, |
| 212 | SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0)) == -1) |
| 213 | return -1; |
| 214 | #else |
| 215 | int flags; |
| 216 | |
| 217 | if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) |
| 218 | return -1; |
| 219 | if ((flags = fcntl(fd, F_GETFD, 0)) == -1 || |
| 220 | fcntl(fd, F_SETFD, flags | FD_CLOEXEC) == -1) |
| 221 | { |
| 222 | close(fd); |
| 223 | return -1; |
| 224 | } |
| 225 | if ((flags = fcntl(fd, F_GETFL, 0)) == -1 || |
| 226 | fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1) |
| 227 | { |
| 228 | close(fd); |
| 229 | return -1; |
| 230 | } |
| 231 | #endif |
| 232 | memset(sa, 0, sizeof(*sa)); |
| 233 | sa->sun_family = AF_UNIX; |
| 234 | if (unpriv) |
| 235 | strlcpy(sa->sun_path, UNPRIVSOCKET, sizeof(sa->sun_path)); |
| 236 | else { |
| 237 | snprintf(sa->sun_path, sizeof(sa->sun_path), CONTROLSOCKET, |
| 238 | ifname ? "-" : "", ifname ? ifname : ""); |
| 239 | } |
| 240 | return fd; |
| 241 | } |
| 242 | |
| 243 | #define S_PRIV (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP) |
| 244 | #define S_UNPRIV (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH) |
| 245 | |
| 246 | static int |
| 247 | control_start1(struct dhcpcd_ctx *ctx, const char *ifname, mode_t fmode) |
| 248 | { |
| 249 | struct sockaddr_un sa; |
| 250 | int fd; |
| 251 | socklen_t len; |
| 252 | |
| 253 | if ((fd = make_sock(&sa, ifname, (fmode & S_UNPRIV) == S_UNPRIV)) == -1) |
| 254 | return -1; |
| 255 | len = (socklen_t)SUN_LEN(&sa); |
| 256 | unlink(sa.sun_path); |
| 257 | if (bind(fd, (struct sockaddr *)&sa, len) == -1 || |
| 258 | chmod(sa.sun_path, fmode) == -1 || |
| 259 | (ctx->control_group && |
| 260 | chown(sa.sun_path, geteuid(), ctx->control_group) == -1) || |
| 261 | listen(fd, sizeof(ctx->control_fds)) == -1) |
| 262 | { |
| 263 | close(fd); |
| 264 | unlink(sa.sun_path); |
| 265 | return -1; |
| 266 | } |
| 267 | |
| 268 | if ((fmode & S_UNPRIV) != S_UNPRIV) |
| 269 | strlcpy(ctx->control_sock, sa.sun_path, |
| 270 | sizeof(ctx->control_sock)); |
| 271 | return fd; |
| 272 | } |
| 273 | |
| 274 | int |
| 275 | control_start(struct dhcpcd_ctx *ctx, const char *ifname) |
| 276 | { |
| 277 | int fd; |
| 278 | |
| 279 | if ((fd = control_start1(ctx, ifname, S_PRIV)) == -1) |
| 280 | return -1; |
| 281 | |
| 282 | ctx->control_fd = fd; |
| 283 | eloop_event_add(ctx->eloop, fd, control_handle, ctx, NULL, NULL); |
| 284 | |
| 285 | if (ifname == NULL && (fd = control_start1(ctx, NULL, S_UNPRIV)) != -1){ |
| 286 | /* We must be in master mode, so create an unpriviledged socket |
| 287 | * to allow normal users to learn the status of dhcpcd. */ |
| 288 | ctx->control_unpriv_fd = fd; |
| 289 | eloop_event_add(ctx->eloop, fd, control_handle_unpriv, |
| 290 | ctx, NULL, NULL); |
| 291 | } |
| 292 | return ctx->control_fd; |
| 293 | } |
| 294 | |
| 295 | int |
| 296 | control_stop(struct dhcpcd_ctx *ctx) |
| 297 | { |
| 298 | int retval = 0; |
| 299 | struct fd_list *l; |
| 300 | |
| 301 | if (ctx->options & DHCPCD_FORKED) |
| 302 | goto freeit; |
| 303 | |
| 304 | if (ctx->control_fd == -1) |
| 305 | return 0; |
| 306 | eloop_event_delete(ctx->eloop, ctx->control_fd, 0); |
| 307 | close(ctx->control_fd); |
| 308 | ctx->control_fd = -1; |
| 309 | if (unlink(ctx->control_sock) == -1) |
| 310 | retval = -1; |
| 311 | |
| 312 | if (ctx->control_unpriv_fd != -1) { |
| 313 | eloop_event_delete(ctx->eloop, ctx->control_unpriv_fd, 0); |
| 314 | close(ctx->control_unpriv_fd); |
| 315 | ctx->control_unpriv_fd = -1; |
| 316 | if (unlink(UNPRIVSOCKET) == -1) |
| 317 | retval = -1; |
| 318 | } |
| 319 | |
| 320 | freeit: |
| 321 | while ((l = TAILQ_FIRST(&ctx->control_fds))) { |
| 322 | TAILQ_REMOVE(&ctx->control_fds, l, next); |
| 323 | eloop_event_delete(ctx->eloop, l->fd, 0); |
| 324 | close(l->fd); |
| 325 | control_queue_free(l); |
| 326 | free(l); |
| 327 | } |
| 328 | |
| 329 | return retval; |
| 330 | } |
| 331 | |
| 332 | int |
| 333 | control_open(struct dhcpcd_ctx *ctx, const char *ifname) |
| 334 | { |
| 335 | struct sockaddr_un sa; |
| 336 | socklen_t len; |
| 337 | |
| 338 | if ((ctx->control_fd = make_sock(&sa, ifname, 0)) == -1) |
| 339 | return -1; |
| 340 | len = (socklen_t)SUN_LEN(&sa); |
| 341 | if (connect(ctx->control_fd, (struct sockaddr *)&sa, len) == -1) { |
| 342 | close(ctx->control_fd); |
| 343 | ctx->control_fd = -1; |
| 344 | return -1; |
| 345 | } |
| 346 | return 0; |
| 347 | } |
| 348 | |
| 349 | ssize_t |
| 350 | control_send(struct dhcpcd_ctx *ctx, int argc, char * const *argv) |
| 351 | { |
| 352 | char buffer[1024]; |
| 353 | int i; |
| 354 | size_t len, l; |
| 355 | |
| 356 | if (argc > 255) { |
| 357 | errno = ENOBUFS; |
| 358 | return -1; |
| 359 | } |
| 360 | len = 0; |
| 361 | for (i = 0; i < argc; i++) { |
| 362 | l = strlen(argv[i]) + 1; |
| 363 | if (len + l > sizeof(buffer)) { |
| 364 | errno = ENOBUFS; |
| 365 | return -1; |
| 366 | } |
| 367 | memcpy(buffer + len, argv[i], l); |
| 368 | len += l; |
| 369 | } |
| 370 | return write(ctx->control_fd, buffer, len); |
| 371 | } |
| 372 | |
| 373 | static void |
| 374 | control_writeone(void *arg) |
| 375 | { |
| 376 | struct fd_list *fd; |
| 377 | struct iovec iov[2]; |
| 378 | struct fd_data *data; |
| 379 | |
| 380 | fd = arg; |
| 381 | data = TAILQ_FIRST(&fd->queue); |
| 382 | iov[0].iov_base = &data->data_len; |
| 383 | iov[0].iov_len = sizeof(size_t); |
| 384 | iov[1].iov_base = data->data; |
| 385 | iov[1].iov_len = data->data_len; |
| 386 | if (writev(fd->fd, iov, 2) == -1) { |
| 387 | logger(fd->ctx, LOG_ERR, |
| 388 | "%s: writev fd %d: %m", __func__, fd->fd); |
| 389 | if (errno != EINTR && errno != EAGAIN) |
| 390 | control_delete(fd); |
| 391 | return; |
| 392 | } |
| 393 | |
| 394 | TAILQ_REMOVE(&fd->queue, data, next); |
| 395 | if (data->freeit) |
| 396 | control_queue_purge(fd->ctx, data->data); |
| 397 | data->data = NULL; /* safety */ |
| 398 | data->data_len = 0; |
| 399 | TAILQ_INSERT_TAIL(&fd->free_queue, data, next); |
| 400 | |
| 401 | if (TAILQ_FIRST(&fd->queue) == NULL) |
| 402 | eloop_event_delete(fd->ctx->eloop, fd->fd, 1); |
| 403 | } |
| 404 | |
| 405 | int |
| 406 | control_queue(struct fd_list *fd, char *data, size_t data_len, uint8_t fit) |
| 407 | { |
| 408 | struct fd_data *d; |
| 409 | size_t n; |
| 410 | |
| 411 | d = TAILQ_FIRST(&fd->free_queue); |
| 412 | if (d) { |
| 413 | TAILQ_REMOVE(&fd->free_queue, d, next); |
| 414 | } else { |
| 415 | n = 0; |
| 416 | TAILQ_FOREACH(d, &fd->queue, next) { |
| 417 | if (++n == CONTROL_QUEUE_MAX) { |
| 418 | errno = ENOBUFS; |
| 419 | return -1; |
| 420 | } |
| 421 | } |
| 422 | d = malloc(sizeof(*d)); |
| 423 | if (d == NULL) |
| 424 | return -1; |
| 425 | } |
| 426 | d->data = data; |
| 427 | d->data_len = data_len; |
| 428 | d->freeit = fit; |
| 429 | TAILQ_INSERT_TAIL(&fd->queue, d, next); |
| 430 | eloop_event_add(fd->ctx->eloop, fd->fd, |
| 431 | NULL, NULL, control_writeone, fd); |
| 432 | return 0; |
| 433 | } |
| 434 | |
| 435 | void |
| 436 | control_close(struct dhcpcd_ctx *ctx) |
| 437 | { |
| 438 | |
| 439 | if (ctx->control_fd != -1) { |
| 440 | close(ctx->control_fd); |
| 441 | ctx->control_fd = -1; |
| 442 | } |
| 443 | } |