src/udev/udev-ctrl.c

   1 /*
   2  * libudev - interface to udev device information
   3  *
   4  * Copyright (C) 2008 Kay Sievers <kay@vrfy.org>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <errno.h>
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <stddef.h>
  16 #include <string.h>
  17 #include <unistd.h>
  18 #include <sys/types.h>
  19 #include <sys/poll.h>
  20 #include <sys/socket.h>
  21 #include <sys/un.h>
  22
  23 #include "udev.h"
  24
  25 /* wire protocol magic must match */
  26 #define UDEV_CTRL_MAGIC                                0xdead1dea
  27
  28 enum udev_ctrl_msg_type {
  29         UDEV_CTRL_UNKNOWN,
  30         UDEV_CTRL_SET_LOG_LEVEL,
  31         UDEV_CTRL_STOP_EXEC_QUEUE,
  32         UDEV_CTRL_START_EXEC_QUEUE,
  33         UDEV_CTRL_RELOAD,
  34         UDEV_CTRL_SET_ENV,
  35         UDEV_CTRL_SET_CHILDREN_MAX,
  36         UDEV_CTRL_PING,
  37         UDEV_CTRL_EXIT,
  38 };
  39
  40 struct udev_ctrl_msg_wire {
  41         char version[16];
  42         unsigned int magic;
  43         enum udev_ctrl_msg_type type;
  44         union {
  45                 int intval;
  46                 char buf[256];
  47         };
  48 };
  49
  50 struct udev_ctrl_msg {
  51         int refcount;
  52         struct udev_ctrl_connection *conn;
  53         struct udev_ctrl_msg_wire ctrl_msg_wire;
  54 };
  55
  56 struct udev_ctrl {
  57         int refcount;
  58         struct udev *udev;
  59         int sock;
  60         struct sockaddr_un saddr;
  61         socklen_t addrlen;
  62         bool bound;
  63         bool cleanup_socket;
  64         bool connected;
  65 };
  66
  67 struct udev_ctrl_connection {
  68         int refcount;
  69         struct udev_ctrl *uctrl;
  70         int sock;
  71 };
  72
  73 struct udev_ctrl *udev_ctrl_new_from_fd(struct udev *udev, int fd)
  74 {
  75         struct udev_ctrl *uctrl;
  76
  77         uctrl = calloc(1, sizeof(struct udev_ctrl));
  78         if (uctrl == NULL)
  79                 return NULL;
  80         uctrl->refcount = 1;
  81         uctrl->udev = udev;
  82
  83         if (fd < 0) {
  84                 uctrl->sock = socket(AF_LOCAL, SOCK_SEQPACKET|SOCK_NONBLOCK|SOCK_CLOEXEC, 0);
  85                 if (uctrl->sock < 0) {
  86                         log_error("error getting socket: %m\n");
  87                         udev_ctrl_unref(uctrl);
  88                         return NULL;
  89                 }
  90         } else {
  91                 uctrl->bound = true;
  92                 uctrl->sock = fd;
  93         }
  94
  95         uctrl->saddr.sun_family = AF_LOCAL;
  96         strscpy(uctrl->saddr.sun_path, sizeof(uctrl->saddr.sun_path), "/run/udev/control");
  97         uctrl->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(uctrl->saddr.sun_path);
  98         return uctrl;
  99 }
 100
 101 struct udev_ctrl *udev_ctrl_new(struct udev *udev)
 102 {
 103         return udev_ctrl_new_from_fd(udev, -1);
 104 }
 105
 106 int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl)
 107 {
 108         int err;
 109
 110         if (!uctrl->bound) {
 111                 err = bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 112                 if (err < 0 && errno == EADDRINUSE) {
 113                         unlink(uctrl->saddr.sun_path);
 114                         err = bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 115                 }
 116
 117                 if (err < 0) {
 118                         err = -errno;
 119                         log_error("bind failed: %m\n");
 120                         return err;
 121                 }
 122
 123                 err = listen(uctrl->sock, 0);
 124                 if (err < 0) {
 125                         err = -errno;
 126                         log_error("listen failed: %m\n");
 127                         return err;
 128                 }
 129
 130                 uctrl->bound = true;
 131                 uctrl->cleanup_socket = true;
 132         }
 133         return 0;
 134 }
 135
 136 struct udev *udev_ctrl_get_udev(struct udev_ctrl *uctrl)
 137 {
 138         return uctrl->udev;
 139 }
 140
 141 struct udev_ctrl *udev_ctrl_ref(struct udev_ctrl *uctrl)
 142 {
 143         if (uctrl == NULL)
 144                 return NULL;
 145         uctrl->refcount++;
 146         return uctrl;
 147 }
 148
 149 struct udev_ctrl *udev_ctrl_unref(struct udev_ctrl *uctrl)
 150 {
 151         if (uctrl == NULL)
 152                 return NULL;
 153         uctrl->refcount--;
 154         if (uctrl->refcount > 0)
 155                 return uctrl;
 156         if (uctrl->sock >= 0)
 157                 close(uctrl->sock);
 158         free(uctrl);
 159         return NULL;
 160 }
 161
 162 int udev_ctrl_cleanup(struct udev_ctrl *uctrl)
 163 {
 164         if (uctrl == NULL)
 165                 return 0;
 166         if (uctrl->cleanup_socket)
 167                 unlink(uctrl->saddr.sun_path);
 168         return 0;
 169 }
 170
 171 int udev_ctrl_get_fd(struct udev_ctrl *uctrl)
 172 {
 173         if (uctrl == NULL)
 174                 return -EINVAL;
 175         return uctrl->sock;
 176 }
 177
 178 struct udev_ctrl_connection *udev_ctrl_get_connection(struct udev_ctrl *uctrl)
 179 {
 180         struct udev_ctrl_connection *conn;
 181         struct ucred ucred;
 182         socklen_t slen;
 183         const int on = 1;
 184
 185         conn = calloc(1, sizeof(struct udev_ctrl_connection));
 186         if (conn == NULL)
 187                 return NULL;
 188         conn->refcount = 1;
 189         conn->uctrl = uctrl;
 190
 191         conn->sock = accept4(uctrl->sock, NULL, NULL, SOCK_CLOEXEC|SOCK_NONBLOCK);
 192         if (conn->sock < 0) {
 193                 if (errno != EINTR)
 194                         log_error("unable to receive ctrl connection: %m\n");
 195                 goto err;
 196         }
 197
 198         /* check peer credential of connection */
 199         slen = sizeof(ucred);
 200         if (getsockopt(conn->sock, SOL_SOCKET, SO_PEERCRED, &ucred, &slen) < 0) {
 201                 log_error("unable to receive credentials of ctrl connection: %m\n");
 202                 goto err;
 203         }
 204         if (ucred.uid > 0) {
 205                 log_error("sender uid=%i, message ignored\n", ucred.uid);
 206                 goto err;
 207         }
 208
 209         /* enable receiving of the sender credentials in the messages */
 210         setsockopt(conn->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 211         udev_ctrl_ref(uctrl);
 212         return conn;
 213 err:
 214         if (conn->sock >= 0)
 215                 close(conn->sock);
 216         free(conn);
 217         return NULL;
 218 }
 219
 220 struct udev_ctrl_connection *udev_ctrl_connection_ref(struct udev_ctrl_connection *conn)
 221 {
 222         if (conn == NULL)
 223                 return NULL;
 224         conn->refcount++;
 225         return conn;
 226 }
 227
 228 struct udev_ctrl_connection *udev_ctrl_connection_unref(struct udev_ctrl_connection *conn)
 229 {
 230         if (conn == NULL)
 231                 return NULL;
 232         conn->refcount--;
 233         if (conn->refcount > 0)
 234                 return conn;
 235         if (conn->sock >= 0)
 236                 close(conn->sock);
 237         udev_ctrl_unref(conn->uctrl);
 238         free(conn);
 239         return NULL;
 240 }
 241
 242 static int ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf, int timeout)
 243 {
 244         struct udev_ctrl_msg_wire ctrl_msg_wire;
 245         int err = 0;
 246
 247         memset(&ctrl_msg_wire, 0x00, sizeof(struct udev_ctrl_msg_wire));
 248         strcpy(ctrl_msg_wire.version, "udev-" VERSION);
 249         ctrl_msg_wire.magic = UDEV_CTRL_MAGIC;
 250         ctrl_msg_wire.type = type;
 251
 252         if (buf != NULL)
 253                 strscpy(ctrl_msg_wire.buf, sizeof(ctrl_msg_wire.buf), buf);
 254         else
 255                 ctrl_msg_wire.intval = intval;
 256
 257         if (!uctrl->connected) {
 258                 if (connect(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen) < 0) {
 259                         err = -errno;
 260                         goto out;
 261                 }
 262                 uctrl->connected = true;
 263         }
 264         if (send(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0) < 0) {
 265                 err = -errno;
 266                 goto out;
 267         }
 268
 269         /* wait for peer message handling or disconnect */
 270         for (;;) {
 271                 struct pollfd pfd[1];
 272                 int r;
 273
 274                 pfd[0].fd = uctrl->sock;
 275                 pfd[0].events = POLLIN;
 276                 r = poll(pfd, 1, timeout * 1000);
 277                 if (r  < 0) {
 278                         if (errno == EINTR)
 279                                 continue;
 280                         err = -errno;
 281                         break;
 282                 }
 283
 284                 if (r > 0 && pfd[0].revents & POLLERR) {
 285                         err = -EIO;
 286                         break;
 287                 }
 288
 289                 if (r == 0)
 290                         err = -ETIMEDOUT;
 291                 break;
 292         }
 293 out:
 294         return err;
 295 }
 296
 297 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority, int timeout)
 298 {
 299         return ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL, timeout);
 300 }
 301
 302 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl, int timeout)
 303 {
 304         return ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL, timeout);
 305 }
 306
 307 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl, int timeout)
 308 {
 309         return ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL, timeout);
 310 }
 311
 312 int udev_ctrl_send_reload(struct udev_ctrl *uctrl, int timeout)
 313 {
 314         return ctrl_send(uctrl, UDEV_CTRL_RELOAD, 0, NULL, timeout);
 315 }
 316
 317 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key, int timeout)
 318 {
 319         return ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, key, timeout);
 320 }
 321
 322 int udev_ctrl_send_set_children_max(struct udev_ctrl *uctrl, int count, int timeout)
 323 {
 324         return ctrl_send(uctrl, UDEV_CTRL_SET_CHILDREN_MAX, count, NULL, timeout);
 325 }
 326
 327 int udev_ctrl_send_ping(struct udev_ctrl *uctrl, int timeout)
 328 {
 329         return ctrl_send(uctrl, UDEV_CTRL_PING, 0, NULL, timeout);
 330 }
 331
 332 int udev_ctrl_send_exit(struct udev_ctrl *uctrl, int timeout)
 333 {
 334         return ctrl_send(uctrl, UDEV_CTRL_EXIT, 0, NULL, timeout);
 335 }
 336
 337 struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl_connection *conn)
 338 {
 339         struct udev_ctrl_msg *uctrl_msg;
 340         ssize_t size;
 341         struct msghdr smsg;
 342         struct cmsghdr *cmsg;
 343         struct iovec iov;
 344         struct ucred *cred;
 345         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 346
 347         uctrl_msg = calloc(1, sizeof(struct udev_ctrl_msg));
 348         if (uctrl_msg == NULL)
 349                 return NULL;
 350         uctrl_msg->refcount = 1;
 351         uctrl_msg->conn = conn;
 352         udev_ctrl_connection_ref(conn);
 353
 354         /* wait for the incoming message */
 355         for(;;) {
 356                 struct pollfd pfd[1];
 357                 int r;
 358
 359                 pfd[0].fd = conn->sock;
 360                 pfd[0].events = POLLIN;
 361
 362                 r = poll(pfd, 1, 10000);
 363                 if (r  < 0) {
 364                         if (errno == EINTR)
 365                                 continue;
 366                         goto err;
 367                 } else if (r == 0) {
 368                         log_error("timeout waiting for ctrl message\n");
 369                         goto err;
 370                 } else {
 371                         if (!(pfd[0].revents & POLLIN)) {
 372                                 log_error("ctrl connection error: %m\n");
 373                                 goto err;
 374                         }
 375                 }
 376
 377                 break;
 378         }
 379
 380         iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 381         iov.iov_len = sizeof(struct udev_ctrl_msg_wire);
 382         memset(&smsg, 0x00, sizeof(struct msghdr));
 383         smsg.msg_iov = &iov;
 384         smsg.msg_iovlen = 1;
 385         smsg.msg_control = cred_msg;
 386         smsg.msg_controllen = sizeof(cred_msg);
 387         size = recvmsg(conn->sock, &smsg, 0);
 388         if (size <  0) {
 389                 log_error("unable to receive ctrl message: %m\n");
 390                 goto err;
 391         }
 392         cmsg = CMSG_FIRSTHDR(&smsg);
 393         cred = (struct ucred *) CMSG_DATA(cmsg);
 394
 395         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 396                 log_error("no sender credentials received, message ignored\n");
 397                 goto err;
 398         }
 399
 400         if (cred->uid != 0) {
 401                 log_error("sender uid=%i, message ignored\n", cred->uid);
 402                 goto err;
 403         }
 404
 405         if (uctrl_msg->ctrl_msg_wire.magic != UDEV_CTRL_MAGIC) {
 406                 log_error("message magic 0x%08x doesn't match, ignore it\n", uctrl_msg->ctrl_msg_wire.magic);
 407                 goto err;
 408         }
 409
 410         return uctrl_msg;
 411 err:
 412         udev_ctrl_msg_unref(uctrl_msg);
 413         return NULL;
 414 }
 415
 416 struct udev_ctrl_msg *udev_ctrl_msg_ref(struct udev_ctrl_msg *ctrl_msg)
 417 {
 418         if (ctrl_msg == NULL)
 419                 return NULL;
 420         ctrl_msg->refcount++;
 421         return ctrl_msg;
 422 }
 423
 424 struct udev_ctrl_msg *udev_ctrl_msg_unref(struct udev_ctrl_msg *ctrl_msg)
 425 {
 426         if (ctrl_msg == NULL)
 427                 return NULL;
 428         ctrl_msg->refcount--;
 429         if (ctrl_msg->refcount > 0)
 430                 return ctrl_msg;
 431         udev_ctrl_connection_unref(ctrl_msg->conn);
 432         free(ctrl_msg);
 433         return NULL;
 434 }
 435
 436 int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg)
 437 {
 438         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_LOG_LEVEL)
 439                 return ctrl_msg->ctrl_msg_wire.intval;
 440         return -1;
 441 }
 442
 443 int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 444 {
 445         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_STOP_EXEC_QUEUE)
 446                 return 1;
 447         return -1;
 448 }
 449
 450 int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 451 {
 452         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_START_EXEC_QUEUE)
 453                 return 1;
 454         return -1;
 455 }
 456
 457 int udev_ctrl_get_reload(struct udev_ctrl_msg *ctrl_msg)
 458 {
 459         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_RELOAD)
 460                 return 1;
 461         return -1;
 462 }
 463
 464 const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg)
 465 {
 466         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_ENV)
 467                 return ctrl_msg->ctrl_msg_wire.buf;
 468         return NULL;
 469 }
 470
 471 int udev_ctrl_get_set_children_max(struct udev_ctrl_msg *ctrl_msg)
 472 {
 473         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_CHILDREN_MAX)
 474                 return ctrl_msg->ctrl_msg_wire.intval;
 475         return -1;
 476 }
 477
 478 int udev_ctrl_get_ping(struct udev_ctrl_msg *ctrl_msg)
 479 {
 480         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_PING)
 481                 return 1;
 482         return -1;
 483 }
 484
 485 int udev_ctrl_get_exit(struct udev_ctrl_msg *ctrl_msg)
 486 {
 487         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_EXIT)
 488                 return 1;
 489         return -1;
 490 }