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         const int on = 1;
  77
  78         uctrl = calloc(1, sizeof(struct udev_ctrl));
  79         if (uctrl == NULL)
  80                 return NULL;
  81         uctrl->refcount = 1;
  82         uctrl->udev = udev;
  83
  84         if (fd < 0) {
  85                 uctrl->sock = socket(AF_LOCAL, SOCK_SEQPACKET|SOCK_NONBLOCK|SOCK_CLOEXEC, 0);
  86                 if (uctrl->sock < 0) {
  87                         log_error("error getting socket: %m");
  88                         udev_ctrl_unref(uctrl);
  89                         return NULL;
  90                 }
  91         } else {
  92                 uctrl->bound = true;
  93                 uctrl->sock = fd;
  94         }
  95         setsockopt(uctrl->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
  96
  97         uctrl->saddr.sun_family = AF_LOCAL;
  98         strscpy(uctrl->saddr.sun_path, sizeof(uctrl->saddr.sun_path), "/run/udev/control");
  99         uctrl->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(uctrl->saddr.sun_path);
 100         return uctrl;
 101 }
 102
 103 struct udev_ctrl *udev_ctrl_new(struct udev *udev)
 104 {
 105         return udev_ctrl_new_from_fd(udev, -1);
 106 }
 107
 108 int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl)
 109 {
 110         int err;
 111
 112         if (!uctrl->bound) {
 113                 err = bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 114                 if (err < 0 && errno == EADDRINUSE) {
 115                         unlink(uctrl->saddr.sun_path);
 116                         err = bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 117                 }
 118
 119                 if (err < 0) {
 120                         err = -errno;
 121                         log_error("bind failed: %m");
 122                         return err;
 123                 }
 124
 125                 err = listen(uctrl->sock, 0);
 126                 if (err < 0) {
 127                         err = -errno;
 128                         log_error("listen failed: %m");
 129                         return err;
 130                 }
 131
 132                 uctrl->bound = true;
 133                 uctrl->cleanup_socket = true;
 134         }
 135         return 0;
 136 }
 137
 138 struct udev *udev_ctrl_get_udev(struct udev_ctrl *uctrl)
 139 {
 140         return uctrl->udev;
 141 }
 142
 143 static struct udev_ctrl *udev_ctrl_ref(struct udev_ctrl *uctrl)
 144 {
 145         if (uctrl == NULL)
 146                 return NULL;
 147         uctrl->refcount++;
 148         return uctrl;
 149 }
 150
 151 struct udev_ctrl *udev_ctrl_unref(struct udev_ctrl *uctrl)
 152 {
 153         if (uctrl == NULL)
 154                 return NULL;
 155         uctrl->refcount--;
 156         if (uctrl->refcount > 0)
 157                 return uctrl;
 158         if (uctrl->sock >= 0)
 159                 close(uctrl->sock);
 160         free(uctrl);
 161         return NULL;
 162 }
 163
 164 int udev_ctrl_cleanup(struct udev_ctrl *uctrl)
 165 {
 166         if (uctrl == NULL)
 167                 return 0;
 168         if (uctrl->cleanup_socket)
 169                 unlink(uctrl->saddr.sun_path);
 170         return 0;
 171 }
 172
 173 int udev_ctrl_get_fd(struct udev_ctrl *uctrl)
 174 {
 175         if (uctrl == NULL)
 176                 return -EINVAL;
 177         return uctrl->sock;
 178 }
 179
 180 struct udev_ctrl_connection *udev_ctrl_get_connection(struct udev_ctrl *uctrl)
 181 {
 182         struct udev_ctrl_connection *conn;
 183         struct ucred ucred;
 184         const int on = 1;
 185         int r;
 186
 187         conn = new(struct udev_ctrl_connection, 1);
 188         if (conn == NULL)
 189                 return NULL;
 190         conn->refcount = 1;
 191         conn->uctrl = uctrl;
 192
 193         conn->sock = accept4(uctrl->sock, NULL, NULL, SOCK_CLOEXEC|SOCK_NONBLOCK);
 194         if (conn->sock < 0) {
 195                 if (errno != EINTR)
 196                         log_error("unable to receive ctrl connection: %m");
 197                 goto err;
 198         }
 199
 200         /* check peer credential of connection */
 201         r = getpeercred(conn->sock, &ucred);
 202         if (r < 0) {
 203                 log_error("unable to receive credentials of ctrl connection: %s", strerror(-r));
 204                 goto err;
 205         }
 206         if (ucred.uid > 0) {
 207                 log_error("sender uid=%i, message ignored", ucred.uid);
 208                 goto err;
 209         }
 210
 211         /* enable receiving of the sender credentials in the messages */
 212         setsockopt(conn->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 213         udev_ctrl_ref(uctrl);
 214         return conn;
 215 err:
 216         if (conn->sock >= 0)
 217                 close(conn->sock);
 218         free(conn);
 219         return NULL;
 220 }
 221
 222 struct udev_ctrl_connection *udev_ctrl_connection_ref(struct udev_ctrl_connection *conn)
 223 {
 224         if (conn == NULL)
 225                 return NULL;
 226         conn->refcount++;
 227         return conn;
 228 }
 229
 230 struct udev_ctrl_connection *udev_ctrl_connection_unref(struct udev_ctrl_connection *conn)
 231 {
 232         if (conn == NULL)
 233                 return NULL;
 234         conn->refcount--;
 235         if (conn->refcount > 0)
 236                 return conn;
 237         if (conn->sock >= 0)
 238                 close(conn->sock);
 239         udev_ctrl_unref(conn->uctrl);
 240         free(conn);
 241         return NULL;
 242 }
 243
 244 static int ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf, int timeout)
 245 {
 246         struct udev_ctrl_msg_wire ctrl_msg_wire;
 247         int err = 0;
 248
 249         memzero(&ctrl_msg_wire, sizeof(struct udev_ctrl_msg_wire));
 250         strcpy(ctrl_msg_wire.version, "udev-" VERSION);
 251         ctrl_msg_wire.magic = UDEV_CTRL_MAGIC;
 252         ctrl_msg_wire.type = type;
 253
 254         if (buf != NULL)
 255                 strscpy(ctrl_msg_wire.buf, sizeof(ctrl_msg_wire.buf), buf);
 256         else
 257                 ctrl_msg_wire.intval = intval;
 258
 259         if (!uctrl->connected) {
 260                 if (connect(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen) < 0) {
 261                         err = -errno;
 262                         goto out;
 263                 }
 264                 uctrl->connected = true;
 265         }
 266         if (send(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0) < 0) {
 267                 err = -errno;
 268                 goto out;
 269         }
 270
 271         /* wait for peer message handling or disconnect */
 272         for (;;) {
 273                 struct pollfd pfd[1];
 274                 int r;
 275
 276                 pfd[0].fd = uctrl->sock;
 277                 pfd[0].events = POLLIN;
 278                 r = poll(pfd, 1, timeout * 1000);
 279                 if (r  < 0) {
 280                         if (errno == EINTR)
 281                                 continue;
 282                         err = -errno;
 283                         break;
 284                 }
 285
 286                 if (r > 0 && pfd[0].revents & POLLERR) {
 287                         err = -EIO;
 288                         break;
 289                 }
 290
 291                 if (r == 0)
 292                         err = -ETIMEDOUT;
 293                 break;
 294         }
 295 out:
 296         return err;
 297 }
 298
 299 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority, int timeout)
 300 {
 301         return ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL, timeout);
 302 }
 303
 304 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl, int timeout)
 305 {
 306         return ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL, timeout);
 307 }
 308
 309 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl, int timeout)
 310 {
 311         return ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL, timeout);
 312 }
 313
 314 int udev_ctrl_send_reload(struct udev_ctrl *uctrl, int timeout)
 315 {
 316         return ctrl_send(uctrl, UDEV_CTRL_RELOAD, 0, NULL, timeout);
 317 }
 318
 319 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key, int timeout)
 320 {
 321         return ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, key, timeout);
 322 }
 323
 324 int udev_ctrl_send_set_children_max(struct udev_ctrl *uctrl, int count, int timeout)
 325 {
 326         return ctrl_send(uctrl, UDEV_CTRL_SET_CHILDREN_MAX, count, NULL, timeout);
 327 }
 328
 329 int udev_ctrl_send_ping(struct udev_ctrl *uctrl, int timeout)
 330 {
 331         return ctrl_send(uctrl, UDEV_CTRL_PING, 0, NULL, timeout);
 332 }
 333
 334 int udev_ctrl_send_exit(struct udev_ctrl *uctrl, int timeout)
 335 {
 336         return ctrl_send(uctrl, UDEV_CTRL_EXIT, 0, NULL, timeout);
 337 }
 338
 339 struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl_connection *conn)
 340 {
 341         struct udev_ctrl_msg *uctrl_msg;
 342         ssize_t size;
 343         struct cmsghdr *cmsg;
 344         struct iovec iov;
 345         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 346         struct msghdr smsg = {
 347                 .msg_iov = &iov,
 348                 .msg_iovlen = 1,
 349                 .msg_control = cred_msg,
 350                 .msg_controllen = sizeof(cred_msg),
 351         };
 352         struct ucred *cred;
 353
 354         uctrl_msg = new0(struct udev_ctrl_msg, 1);
 355         if (uctrl_msg == NULL)
 356                 return NULL;
 357         uctrl_msg->refcount = 1;
 358         uctrl_msg->conn = conn;
 359         udev_ctrl_connection_ref(conn);
 360
 361         /* wait for the incoming message */
 362         for (;;) {
 363                 struct pollfd pfd[1];
 364                 int r;
 365
 366                 pfd[0].fd = conn->sock;
 367                 pfd[0].events = POLLIN;
 368
 369                 r = poll(pfd, 1, 10000);
 370                 if (r  < 0) {
 371                         if (errno == EINTR)
 372                                 continue;
 373                         goto err;
 374                 } else if (r == 0) {
 375                         log_error("timeout waiting for ctrl message");
 376                         goto err;
 377                 } else {
 378                         if (!(pfd[0].revents & POLLIN)) {
 379                                 log_error("ctrl connection error: %m");
 380                                 goto err;
 381                         }
 382                 }
 383
 384                 break;
 385         }
 386
 387         iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 388         iov.iov_len = sizeof(struct udev_ctrl_msg_wire);
 389
 390         size = recvmsg(conn->sock, &smsg, 0);
 391         if (size <  0) {
 392                 log_error("unable to receive ctrl message: %m");
 393                 goto err;
 394         }
 395         cmsg = CMSG_FIRSTHDR(&smsg);
 396         cred = (struct ucred *) CMSG_DATA(cmsg);
 397
 398         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 399                 log_error("no sender credentials received, message ignored");
 400                 goto err;
 401         }
 402
 403         if (cred->uid != 0) {
 404                 log_error("sender uid=%i, message ignored", cred->uid);
 405                 goto err;
 406         }
 407
 408         if (uctrl_msg->ctrl_msg_wire.magic != UDEV_CTRL_MAGIC) {
 409                 log_error("message magic 0x%08x doesn't match, ignore it", uctrl_msg->ctrl_msg_wire.magic);
 410                 goto err;
 411         }
 412
 413         return uctrl_msg;
 414 err:
 415         udev_ctrl_msg_unref(uctrl_msg);
 416         return NULL;
 417 }
 418
 419 struct udev_ctrl_msg *udev_ctrl_msg_unref(struct udev_ctrl_msg *ctrl_msg)
 420 {
 421         if (ctrl_msg == NULL)
 422                 return NULL;
 423         ctrl_msg->refcount--;
 424         if (ctrl_msg->refcount > 0)
 425                 return ctrl_msg;
 426         udev_ctrl_connection_unref(ctrl_msg->conn);
 427         free(ctrl_msg);
 428         return NULL;
 429 }
 430
 431 int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg)
 432 {
 433         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_LOG_LEVEL)
 434                 return ctrl_msg->ctrl_msg_wire.intval;
 435         return -1;
 436 }
 437
 438 int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 439 {
 440         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_STOP_EXEC_QUEUE)
 441                 return 1;
 442         return -1;
 443 }
 444
 445 int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 446 {
 447         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_START_EXEC_QUEUE)
 448                 return 1;
 449         return -1;
 450 }
 451
 452 int udev_ctrl_get_reload(struct udev_ctrl_msg *ctrl_msg)
 453 {
 454         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_RELOAD)
 455                 return 1;
 456         return -1;
 457 }
 458
 459 const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg)
 460 {
 461         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_ENV)
 462                 return ctrl_msg->ctrl_msg_wire.buf;
 463         return NULL;
 464 }
 465
 466 int udev_ctrl_get_set_children_max(struct udev_ctrl_msg *ctrl_msg)
 467 {
 468         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_CHILDREN_MAX)
 469                 return ctrl_msg->ctrl_msg_wire.intval;
 470         return -1;
 471 }
 472
 473 int udev_ctrl_get_ping(struct udev_ctrl_msg *ctrl_msg)
 474 {
 475         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_PING)
 476                 return 1;
 477         return -1;
 478 }
 479
 480 int udev_ctrl_get_exit(struct udev_ctrl_msg *ctrl_msg)
 481 {
 482         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_EXIT)
 483                 return 1;
 484         return -1;
 485 }