udev/udev-ctrl.c

   1 /*
   2  * libudev - interface to udev device information
   3  *
   4  * Copyright (C) 2008 Kay Sievers <kay.sievers@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_RULES,
  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                         err(udev, "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         util_strscpyl(uctrl->saddr.sun_path, sizeof(uctrl->saddr.sun_path),
  97                       udev_get_run_path(udev), "/control", NULL);
  98         uctrl->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(uctrl->saddr.sun_path);
  99         return uctrl;
 100 }
 101
 102 struct udev_ctrl *udev_ctrl_new(struct udev *udev)
 103 {
 104         return udev_ctrl_new_from_fd(udev, -1);
 105 }
 106
 107 int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl)
 108 {
 109         int err;
 110
 111         if (!uctrl->bound) {
 112                 err = bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 113                 if (err < 0 && errno == EADDRINUSE) {
 114                         unlink(uctrl->saddr.sun_path);
 115                         err = bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 116                 }
 117
 118                 if (err < 0) {
 119                         err = -errno;
 120                         err(uctrl->udev, "bind failed: %m\n");
 121                         return err;
 122                 }
 123
 124                 err = listen(uctrl->sock, 0);
 125                 if (err < 0) {
 126                         err = -errno;
 127                         err(uctrl->udev, "listen failed: %m\n");
 128                         return err;
 129                 }
 130
 131                 uctrl->bound = true;
 132                 uctrl->cleanup_socket = true;
 133         }
 134         return 0;
 135 }
 136
 137 struct udev *udev_ctrl_get_udev(struct udev_ctrl *uctrl)
 138 {
 139         return uctrl->udev;
 140 }
 141
 142 struct udev_ctrl *udev_ctrl_ref(struct udev_ctrl *uctrl)
 143 {
 144         if (uctrl == NULL)
 145                 return NULL;
 146         uctrl->refcount++;
 147         return uctrl;
 148 }
 149
 150 struct udev_ctrl *udev_ctrl_unref(struct udev_ctrl *uctrl)
 151 {
 152         if (uctrl == NULL)
 153                 return NULL;
 154         uctrl->refcount--;
 155         if (uctrl->refcount > 0)
 156                 return uctrl;
 157         if (uctrl->sock >= 0)
 158                 close(uctrl->sock);
 159         if (uctrl->cleanup_socket)
 160                 unlink(uctrl->saddr.sun_path);
 161         free(uctrl);
 162         return NULL;
 163 }
 164
 165 int udev_ctrl_get_fd(struct udev_ctrl *uctrl)
 166 {
 167         if (uctrl == NULL)
 168                 return -1;
 169         return uctrl->sock;
 170 }
 171
 172 struct udev_ctrl_connection *udev_ctrl_get_connection(struct udev_ctrl *uctrl)
 173 {
 174         struct udev_ctrl_connection *conn;
 175         struct ucred ucred;
 176         socklen_t slen;
 177         const int on = 1;
 178
 179         conn = calloc(1, sizeof(struct udev_ctrl_connection));
 180         if (conn == NULL)
 181                 return NULL;
 182         conn->refcount = 1;
 183         conn->uctrl = uctrl;
 184
 185         conn->sock = accept4(uctrl->sock, NULL, NULL, SOCK_CLOEXEC|SOCK_NONBLOCK);
 186         if (conn->sock < 0) {
 187                 if (errno != EINTR)
 188                         err(uctrl->udev, "unable to receive ctrl connection: %m\n");
 189                 goto err;
 190         }
 191
 192         /* check peer credential of connection */
 193         slen = sizeof(ucred);
 194         if (getsockopt(conn->sock, SOL_SOCKET, SO_PEERCRED, &ucred, &slen) < 0) {
 195                 err(uctrl->udev, "unable to receive credentials of ctrl connection: %m\n");
 196                 goto err;
 197         }
 198         if (ucred.uid > 0) {
 199                 err(uctrl->udev, "sender uid=%i, message ignored\n", ucred.uid);
 200                 goto err;
 201         }
 202
 203         /* enable receiving of the sender credentials in the messages */
 204         setsockopt(conn->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 205         udev_ctrl_ref(uctrl);
 206         return conn;
 207 err:
 208         if (conn->sock >= 0)
 209                 close(conn->sock);
 210         free(conn);
 211         return NULL;
 212 }
 213
 214 struct udev_ctrl_connection *udev_ctrl_connection_ref(struct udev_ctrl_connection *conn)
 215 {
 216         if (conn == NULL)
 217                 return NULL;
 218         conn->refcount++;
 219         return conn;
 220 }
 221
 222 struct udev_ctrl_connection *udev_ctrl_connection_unref(struct udev_ctrl_connection *conn)
 223 {
 224         if (conn == NULL)
 225                 return NULL;
 226         conn->refcount--;
 227         if (conn->refcount > 0)
 228                 return conn;
 229         if (conn->sock >= 0)
 230                 close(conn->sock);
 231         udev_ctrl_unref(conn->uctrl);
 232         free(conn);
 233         return NULL;
 234 }
 235
 236 static int ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf, int timeout)
 237 {
 238         struct udev_ctrl_msg_wire ctrl_msg_wire;
 239         int err = 0;
 240
 241         memset(&ctrl_msg_wire, 0x00, sizeof(struct udev_ctrl_msg_wire));
 242         strcpy(ctrl_msg_wire.version, "udev-" VERSION);
 243         ctrl_msg_wire.magic = UDEV_CTRL_MAGIC;
 244         ctrl_msg_wire.type = type;
 245
 246         if (buf != NULL)
 247                 util_strscpy(ctrl_msg_wire.buf, sizeof(ctrl_msg_wire.buf), buf);
 248         else
 249                 ctrl_msg_wire.intval = intval;
 250
 251         if (!uctrl->connected) {
 252                 if (connect(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen) < 0) {
 253                         err = -errno;
 254                         goto out;
 255                 }
 256                 uctrl->connected = true;
 257         }
 258         if (send(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0) < 0) {
 259                 err = -errno;
 260                 goto out;
 261         }
 262
 263         /* wait for peer message handling or disconnect */
 264         for (;;) {
 265                 struct pollfd pfd[1];
 266                 int r;
 267
 268                 pfd[0].fd = uctrl->sock;
 269                 pfd[0].events = POLLIN;
 270                 r = poll(pfd, 1, timeout * 1000);
 271                 if (r  < 0) {
 272                         if (errno == EINTR)
 273                                 continue;
 274                         err = -errno;
 275                         break;
 276                 }
 277
 278                 if (r > 0 && pfd[0].revents & POLLERR) {
 279                         err = -EIO;
 280                         break;
 281                 }
 282
 283                 if (r == 0)
 284                         err = -ETIMEDOUT;
 285                 break;
 286         }
 287 out:
 288         return err;
 289 }
 290
 291 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority, int timeout)
 292 {
 293         return ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL, timeout);
 294 }
 295
 296 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl, int timeout)
 297 {
 298         return ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL, timeout);
 299 }
 300
 301 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl, int timeout)
 302 {
 303         return ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL, timeout);
 304 }
 305
 306 int udev_ctrl_send_reload_rules(struct udev_ctrl *uctrl, int timeout)
 307 {
 308         return ctrl_send(uctrl, UDEV_CTRL_RELOAD_RULES, 0, NULL, timeout);
 309 }
 310
 311 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key, int timeout)
 312 {
 313         return ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, key, timeout);
 314 }
 315
 316 int udev_ctrl_send_set_children_max(struct udev_ctrl *uctrl, int count, int timeout)
 317 {
 318         return ctrl_send(uctrl, UDEV_CTRL_SET_CHILDREN_MAX, count, NULL, timeout);
 319 }
 320
 321 int udev_ctrl_send_ping(struct udev_ctrl *uctrl, int timeout)
 322 {
 323         return ctrl_send(uctrl, UDEV_CTRL_PING, 0, NULL, timeout);
 324 }
 325
 326 int udev_ctrl_send_exit(struct udev_ctrl *uctrl, int timeout)
 327 {
 328         return ctrl_send(uctrl, UDEV_CTRL_EXIT, 0, NULL, timeout);
 329 }
 330
 331 struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl_connection *conn)
 332 {
 333         struct udev *udev = conn->uctrl->udev;
 334         struct udev_ctrl_msg *uctrl_msg;
 335         ssize_t size;
 336         struct msghdr smsg;
 337         struct cmsghdr *cmsg;
 338         struct iovec iov;
 339         struct ucred *cred;
 340         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 341
 342         uctrl_msg = calloc(1, sizeof(struct udev_ctrl_msg));
 343         if (uctrl_msg == NULL)
 344                 return NULL;
 345         uctrl_msg->refcount = 1;
 346         uctrl_msg->conn = conn;
 347         udev_ctrl_connection_ref(conn);
 348
 349         /* wait for the incoming message */
 350         for(;;) {
 351                 struct pollfd pfd[1];
 352                 int r;
 353
 354                 pfd[0].fd = conn->sock;
 355                 pfd[0].events = POLLIN;
 356
 357                 r = poll(pfd, 1, 10000);
 358                 if (r  < 0) {
 359                         if (errno == EINTR)
 360                                 continue;
 361                         goto err;
 362                 } else if (r == 0) {
 363                         err(udev, "timeout waiting for ctrl message\n");
 364                         goto err;
 365                 } else {
 366                         if (!(pfd[0].revents & POLLIN)) {
 367                                 err(udev, "ctrl connection error: %m\n");
 368                                 goto err;
 369                         }
 370                 }
 371
 372                 break;
 373         }
 374
 375         iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 376         iov.iov_len = sizeof(struct udev_ctrl_msg_wire);
 377         memset(&smsg, 0x00, sizeof(struct msghdr));
 378         smsg.msg_iov = &iov;
 379         smsg.msg_iovlen = 1;
 380         smsg.msg_control = cred_msg;
 381         smsg.msg_controllen = sizeof(cred_msg);
 382         size = recvmsg(conn->sock, &smsg, 0);
 383         if (size <  0) {
 384                 err(udev, "unable to receive ctrl message: %m\n");
 385                 goto err;
 386         }
 387         cmsg = CMSG_FIRSTHDR(&smsg);
 388         cred = (struct ucred *) CMSG_DATA(cmsg);
 389
 390         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 391                 err(udev, "no sender credentials received, message ignored\n");
 392                 goto err;
 393         }
 394
 395         if (cred->uid != 0) {
 396                 err(udev, "sender uid=%i, message ignored\n", cred->uid);
 397                 goto err;
 398         }
 399
 400         if (uctrl_msg->ctrl_msg_wire.magic != UDEV_CTRL_MAGIC) {
 401                 err(udev, "message magic 0x%08x doesn't match, ignore it\n", uctrl_msg->ctrl_msg_wire.magic);
 402                 goto err;
 403         }
 404
 405         dbg(udev, "created ctrl_msg %p (%i)\n", uctrl_msg, uctrl_msg->ctrl_msg_wire.type);
 406         return uctrl_msg;
 407 err:
 408         udev_ctrl_msg_unref(uctrl_msg);
 409         return NULL;
 410 }
 411
 412 struct udev_ctrl_msg *udev_ctrl_msg_ref(struct udev_ctrl_msg *ctrl_msg)
 413 {
 414         if (ctrl_msg == NULL)
 415                 return NULL;
 416         ctrl_msg->refcount++;
 417         return ctrl_msg;
 418 }
 419
 420 struct udev_ctrl_msg *udev_ctrl_msg_unref(struct udev_ctrl_msg *ctrl_msg)
 421 {
 422         if (ctrl_msg == NULL)
 423                 return NULL;
 424         ctrl_msg->refcount--;
 425         if (ctrl_msg->refcount > 0)
 426                 return ctrl_msg;
 427         dbg(ctrl_msg->conn->uctrl->udev, "release ctrl_msg %p\n", ctrl_msg);
 428         udev_ctrl_connection_unref(ctrl_msg->conn);
 429         free(ctrl_msg);
 430         return NULL;
 431 }
 432
 433 int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg)
 434 {
 435         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_LOG_LEVEL)
 436                 return ctrl_msg->ctrl_msg_wire.intval;
 437         return -1;
 438 }
 439
 440 int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 441 {
 442         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_STOP_EXEC_QUEUE)
 443                 return 1;
 444         return -1;
 445 }
 446
 447 int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 448 {
 449         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_START_EXEC_QUEUE)
 450                 return 1;
 451         return -1;
 452 }
 453
 454 int udev_ctrl_get_reload_rules(struct udev_ctrl_msg *ctrl_msg)
 455 {
 456         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_RELOAD_RULES)
 457                 return 1;
 458         return -1;
 459 }
 460
 461 const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg)
 462 {
 463         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_ENV)
 464                 return ctrl_msg->ctrl_msg_wire.buf;
 465         return NULL;
 466 }
 467
 468 int udev_ctrl_get_set_children_max(struct udev_ctrl_msg *ctrl_msg)
 469 {
 470         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_CHILDREN_MAX)
 471                 return ctrl_msg->ctrl_msg_wire.intval;
 472         return -1;
 473 }
 474
 475 int udev_ctrl_get_ping(struct udev_ctrl_msg *ctrl_msg)
 476 {
 477         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_PING)
 478                 return 1;
 479         return -1;
 480 }
 481
 482 int udev_ctrl_get_exit(struct udev_ctrl_msg *ctrl_msg)
 483 {
 484         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_EXIT)
 485                 return 1;
 486         return -1;
 487 }