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         free(uctrl);
 160         return NULL;
 161 }
 162
 163 int udev_ctrl_cleanup(struct udev_ctrl *uctrl)
 164 {
 165         if (uctrl->cleanup_socket)
 166                 unlink(uctrl->saddr.sun_path);
 167         return 0;
 168 }
 169
 170 int udev_ctrl_get_fd(struct udev_ctrl *uctrl)
 171 {
 172         if (uctrl == NULL)
 173                 return -1;
 174         return uctrl->sock;
 175 }
 176
 177 struct udev_ctrl_connection *udev_ctrl_get_connection(struct udev_ctrl *uctrl)
 178 {
 179         struct udev_ctrl_connection *conn;
 180         struct ucred ucred;
 181         socklen_t slen;
 182         const int on = 1;
 183
 184         conn = calloc(1, sizeof(struct udev_ctrl_connection));
 185         if (conn == NULL)
 186                 return NULL;
 187         conn->refcount = 1;
 188         conn->uctrl = uctrl;
 189
 190         conn->sock = accept4(uctrl->sock, NULL, NULL, SOCK_CLOEXEC|SOCK_NONBLOCK);
 191         if (conn->sock < 0) {
 192                 if (errno != EINTR)
 193                         err(uctrl->udev, "unable to receive ctrl connection: %m\n");
 194                 goto err;
 195         }
 196
 197         /* check peer credential of connection */
 198         slen = sizeof(ucred);
 199         if (getsockopt(conn->sock, SOL_SOCKET, SO_PEERCRED, &ucred, &slen) < 0) {
 200                 err(uctrl->udev, "unable to receive credentials of ctrl connection: %m\n");
 201                 goto err;
 202         }
 203         if (ucred.uid > 0) {
 204                 err(uctrl->udev, "sender uid=%i, message ignored\n", ucred.uid);
 205                 goto err;
 206         }
 207
 208         /* enable receiving of the sender credentials in the messages */
 209         setsockopt(conn->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 210         udev_ctrl_ref(uctrl);
 211         return conn;
 212 err:
 213         if (conn->sock >= 0)
 214                 close(conn->sock);
 215         free(conn);
 216         return NULL;
 217 }
 218
 219 struct udev_ctrl_connection *udev_ctrl_connection_ref(struct udev_ctrl_connection *conn)
 220 {
 221         if (conn == NULL)
 222                 return NULL;
 223         conn->refcount++;
 224         return conn;
 225 }
 226
 227 struct udev_ctrl_connection *udev_ctrl_connection_unref(struct udev_ctrl_connection *conn)
 228 {
 229         if (conn == NULL)
 230                 return NULL;
 231         conn->refcount--;
 232         if (conn->refcount > 0)
 233                 return conn;
 234         if (conn->sock >= 0)
 235                 close(conn->sock);
 236         udev_ctrl_unref(conn->uctrl);
 237         free(conn);
 238         return NULL;
 239 }
 240
 241 static int ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf, int timeout)
 242 {
 243         struct udev_ctrl_msg_wire ctrl_msg_wire;
 244         int err = 0;
 245
 246         memset(&ctrl_msg_wire, 0x00, sizeof(struct udev_ctrl_msg_wire));
 247         strcpy(ctrl_msg_wire.version, "udev-" VERSION);
 248         ctrl_msg_wire.magic = UDEV_CTRL_MAGIC;
 249         ctrl_msg_wire.type = type;
 250
 251         if (buf != NULL)
 252                 util_strscpy(ctrl_msg_wire.buf, sizeof(ctrl_msg_wire.buf), buf);
 253         else
 254                 ctrl_msg_wire.intval = intval;
 255
 256         if (!uctrl->connected) {
 257                 if (connect(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen) < 0) {
 258                         err = -errno;
 259                         goto out;
 260                 }
 261                 uctrl->connected = true;
 262         }
 263         if (send(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0) < 0) {
 264                 err = -errno;
 265                 goto out;
 266         }
 267
 268         /* wait for peer message handling or disconnect */
 269         for (;;) {
 270                 struct pollfd pfd[1];
 271                 int r;
 272
 273                 pfd[0].fd = uctrl->sock;
 274                 pfd[0].events = POLLIN;
 275                 r = poll(pfd, 1, timeout * 1000);
 276                 if (r  < 0) {
 277                         if (errno == EINTR)
 278                                 continue;
 279                         err = -errno;
 280                         break;
 281                 }
 282
 283                 if (r > 0 && pfd[0].revents & POLLERR) {
 284                         err = -EIO;
 285                         break;
 286                 }
 287
 288                 if (r == 0)
 289                         err = -ETIMEDOUT;
 290                 break;
 291         }
 292 out:
 293         return err;
 294 }
 295
 296 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority, int timeout)
 297 {
 298         return ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL, timeout);
 299 }
 300
 301 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl, int timeout)
 302 {
 303         return ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL, timeout);
 304 }
 305
 306 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl, int timeout)
 307 {
 308         return ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL, timeout);
 309 }
 310
 311 int udev_ctrl_send_reload_rules(struct udev_ctrl *uctrl, int timeout)
 312 {
 313         return ctrl_send(uctrl, UDEV_CTRL_RELOAD_RULES, 0, NULL, timeout);
 314 }
 315
 316 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key, int timeout)
 317 {
 318         return ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, key, timeout);
 319 }
 320
 321 int udev_ctrl_send_set_children_max(struct udev_ctrl *uctrl, int count, int timeout)
 322 {
 323         return ctrl_send(uctrl, UDEV_CTRL_SET_CHILDREN_MAX, count, NULL, timeout);
 324 }
 325
 326 int udev_ctrl_send_ping(struct udev_ctrl *uctrl, int timeout)
 327 {
 328         return ctrl_send(uctrl, UDEV_CTRL_PING, 0, NULL, timeout);
 329 }
 330
 331 int udev_ctrl_send_exit(struct udev_ctrl *uctrl, int timeout)
 332 {
 333         return ctrl_send(uctrl, UDEV_CTRL_EXIT, 0, NULL, timeout);
 334 }
 335
 336 struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl_connection *conn)
 337 {
 338         struct udev *udev = conn->uctrl->udev;
 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                         err(udev, "timeout waiting for ctrl message\n");
 369                         goto err;
 370                 } else {
 371                         if (!(pfd[0].revents & POLLIN)) {
 372                                 err(udev, "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                 err(udev, "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                 err(udev, "no sender credentials received, message ignored\n");
 397                 goto err;
 398         }
 399
 400         if (cred->uid != 0) {
 401                 err(udev, "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                 err(udev, "message magic 0x%08x doesn't match, ignore it\n", uctrl_msg->ctrl_msg_wire.magic);
 407                 goto err;
 408         }
 409
 410         dbg(udev, "created ctrl_msg %p (%i)\n", uctrl_msg, uctrl_msg->ctrl_msg_wire.type);
 411         return uctrl_msg;
 412 err:
 413         udev_ctrl_msg_unref(uctrl_msg);
 414         return NULL;
 415 }
 416
 417 struct udev_ctrl_msg *udev_ctrl_msg_ref(struct udev_ctrl_msg *ctrl_msg)
 418 {
 419         if (ctrl_msg == NULL)
 420                 return NULL;
 421         ctrl_msg->refcount++;
 422         return ctrl_msg;
 423 }
 424
 425 struct udev_ctrl_msg *udev_ctrl_msg_unref(struct udev_ctrl_msg *ctrl_msg)
 426 {
 427         if (ctrl_msg == NULL)
 428                 return NULL;
 429         ctrl_msg->refcount--;
 430         if (ctrl_msg->refcount > 0)
 431                 return ctrl_msg;
 432         dbg(ctrl_msg->conn->uctrl->udev, "release ctrl_msg %p\n", ctrl_msg);
 433         udev_ctrl_connection_unref(ctrl_msg->conn);
 434         free(ctrl_msg);
 435         return NULL;
 436 }
 437
 438 int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg)
 439 {
 440         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_LOG_LEVEL)
 441                 return ctrl_msg->ctrl_msg_wire.intval;
 442         return -1;
 443 }
 444
 445 int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 446 {
 447         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_STOP_EXEC_QUEUE)
 448                 return 1;
 449         return -1;
 450 }
 451
 452 int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 453 {
 454         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_START_EXEC_QUEUE)
 455                 return 1;
 456         return -1;
 457 }
 458
 459 int udev_ctrl_get_reload_rules(struct udev_ctrl_msg *ctrl_msg)
 460 {
 461         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_RELOAD_RULES)
 462                 return 1;
 463         return -1;
 464 }
 465
 466 const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg)
 467 {
 468         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_ENV)
 469                 return ctrl_msg->ctrl_msg_wire.buf;
 470         return NULL;
 471 }
 472
 473 int udev_ctrl_get_set_children_max(struct udev_ctrl_msg *ctrl_msg)
 474 {
 475         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_CHILDREN_MAX)
 476                 return ctrl_msg->ctrl_msg_wire.intval;
 477         return -1;
 478 }
 479
 480 int udev_ctrl_get_ping(struct udev_ctrl_msg *ctrl_msg)
 481 {
 482         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_PING)
 483                 return 1;
 484         return -1;
 485 }
 486
 487 int udev_ctrl_get_exit(struct udev_ctrl_msg *ctrl_msg)
 488 {
 489         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_EXIT)
 490                 return 1;
 491         return -1;
 492 }