src/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,
  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 == NULL)
 166                 return 0;
 167         if (uctrl->cleanup_socket)
 168                 unlink(uctrl->saddr.sun_path);
 169         return 0;
 170 }
 171
 172 int udev_ctrl_get_fd(struct udev_ctrl *uctrl)
 173 {
 174         if (uctrl == NULL)
 175                 return -EINVAL;
 176         return uctrl->sock;
 177 }
 178
 179 struct udev_ctrl_connection *udev_ctrl_get_connection(struct udev_ctrl *uctrl)
 180 {
 181         struct udev_ctrl_connection *conn;
 182         struct ucred ucred;
 183         socklen_t slen;
 184         const int on = 1;
 185
 186         conn = calloc(1, sizeof(struct udev_ctrl_connection));
 187         if (conn == NULL)
 188                 return NULL;
 189         conn->refcount = 1;
 190         conn->uctrl = uctrl;
 191
 192         conn->sock = accept4(uctrl->sock, NULL, NULL, SOCK_CLOEXEC|SOCK_NONBLOCK);
 193         if (conn->sock < 0) {
 194                 if (errno != EINTR)
 195                         err(uctrl->udev, "unable to receive ctrl connection: %m\n");
 196                 goto err;
 197         }
 198
 199         /* check peer credential of connection */
 200         slen = sizeof(ucred);
 201         if (getsockopt(conn->sock, SOL_SOCKET, SO_PEERCRED, &ucred, &slen) < 0) {
 202                 err(uctrl->udev, "unable to receive credentials of ctrl connection: %m\n");
 203                 goto err;
 204         }
 205         if (ucred.uid > 0) {
 206                 err(uctrl->udev, "sender uid=%i, message ignored\n", ucred.uid);
 207                 goto err;
 208         }
 209
 210         /* enable receiving of the sender credentials in the messages */
 211         setsockopt(conn->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 212         udev_ctrl_ref(uctrl);
 213         return conn;
 214 err:
 215         if (conn->sock >= 0)
 216                 close(conn->sock);
 217         free(conn);
 218         return NULL;
 219 }
 220
 221 struct udev_ctrl_connection *udev_ctrl_connection_ref(struct udev_ctrl_connection *conn)
 222 {
 223         if (conn == NULL)
 224                 return NULL;
 225         conn->refcount++;
 226         return conn;
 227 }
 228
 229 struct udev_ctrl_connection *udev_ctrl_connection_unref(struct udev_ctrl_connection *conn)
 230 {
 231         if (conn == NULL)
 232                 return NULL;
 233         conn->refcount--;
 234         if (conn->refcount > 0)
 235                 return conn;
 236         if (conn->sock >= 0)
 237                 close(conn->sock);
 238         udev_ctrl_unref(conn->uctrl);
 239         free(conn);
 240         return NULL;
 241 }
 242
 243 static int ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf, int timeout)
 244 {
 245         struct udev_ctrl_msg_wire ctrl_msg_wire;
 246         int err = 0;
 247
 248         memset(&ctrl_msg_wire, 0x00, sizeof(struct udev_ctrl_msg_wire));
 249         strcpy(ctrl_msg_wire.version, "udev-" VERSION);
 250         ctrl_msg_wire.magic = UDEV_CTRL_MAGIC;
 251         ctrl_msg_wire.type = type;
 252
 253         if (buf != NULL)
 254                 util_strscpy(ctrl_msg_wire.buf, sizeof(ctrl_msg_wire.buf), buf);
 255         else
 256                 ctrl_msg_wire.intval = intval;
 257
 258         if (!uctrl->connected) {
 259                 if (connect(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen) < 0) {
 260                         err = -errno;
 261                         goto out;
 262                 }
 263                 uctrl->connected = true;
 264         }
 265         if (send(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0) < 0) {
 266                 err = -errno;
 267                 goto out;
 268         }
 269
 270         /* wait for peer message handling or disconnect */
 271         for (;;) {
 272                 struct pollfd pfd[1];
 273                 int r;
 274
 275                 pfd[0].fd = uctrl->sock;
 276                 pfd[0].events = POLLIN;
 277                 r = poll(pfd, 1, timeout * 1000);
 278                 if (r  < 0) {
 279                         if (errno == EINTR)
 280                                 continue;
 281                         err = -errno;
 282                         break;
 283                 }
 284
 285                 if (r > 0 && pfd[0].revents & POLLERR) {
 286                         err = -EIO;
 287                         break;
 288                 }
 289
 290                 if (r == 0)
 291                         err = -ETIMEDOUT;
 292                 break;
 293         }
 294 out:
 295         return err;
 296 }
 297
 298 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority, int timeout)
 299 {
 300         return ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL, timeout);
 301 }
 302
 303 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl, int timeout)
 304 {
 305         return ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL, timeout);
 306 }
 307
 308 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl, int timeout)
 309 {
 310         return ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL, timeout);
 311 }
 312
 313 int udev_ctrl_send_reload(struct udev_ctrl *uctrl, int timeout)
 314 {
 315         return ctrl_send(uctrl, UDEV_CTRL_RELOAD, 0, NULL, timeout);
 316 }
 317
 318 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key, int timeout)
 319 {
 320         return ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, key, timeout);
 321 }
 322
 323 int udev_ctrl_send_set_children_max(struct udev_ctrl *uctrl, int count, int timeout)
 324 {
 325         return ctrl_send(uctrl, UDEV_CTRL_SET_CHILDREN_MAX, count, NULL, timeout);
 326 }
 327
 328 int udev_ctrl_send_ping(struct udev_ctrl *uctrl, int timeout)
 329 {
 330         return ctrl_send(uctrl, UDEV_CTRL_PING, 0, NULL, timeout);
 331 }
 332
 333 int udev_ctrl_send_exit(struct udev_ctrl *uctrl, int timeout)
 334 {
 335         return ctrl_send(uctrl, UDEV_CTRL_EXIT, 0, NULL, timeout);
 336 }
 337
 338 struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl_connection *conn)
 339 {
 340         struct udev *udev = conn->uctrl->udev;
 341         struct udev_ctrl_msg *uctrl_msg;
 342         ssize_t size;
 343         struct msghdr smsg;
 344         struct cmsghdr *cmsg;
 345         struct iovec iov;
 346         struct ucred *cred;
 347         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 348
 349         uctrl_msg = calloc(1, sizeof(struct udev_ctrl_msg));
 350         if (uctrl_msg == NULL)
 351                 return NULL;
 352         uctrl_msg->refcount = 1;
 353         uctrl_msg->conn = conn;
 354         udev_ctrl_connection_ref(conn);
 355
 356         /* wait for the incoming message */
 357         for(;;) {
 358                 struct pollfd pfd[1];
 359                 int r;
 360
 361                 pfd[0].fd = conn->sock;
 362                 pfd[0].events = POLLIN;
 363
 364                 r = poll(pfd, 1, 10000);
 365                 if (r  < 0) {
 366                         if (errno == EINTR)
 367                                 continue;
 368                         goto err;
 369                 } else if (r == 0) {
 370                         err(udev, "timeout waiting for ctrl message\n");
 371                         goto err;
 372                 } else {
 373                         if (!(pfd[0].revents & POLLIN)) {
 374                                 err(udev, "ctrl connection error: %m\n");
 375                                 goto err;
 376                         }
 377                 }
 378
 379                 break;
 380         }
 381
 382         iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 383         iov.iov_len = sizeof(struct udev_ctrl_msg_wire);
 384         memset(&smsg, 0x00, sizeof(struct msghdr));
 385         smsg.msg_iov = &iov;
 386         smsg.msg_iovlen = 1;
 387         smsg.msg_control = cred_msg;
 388         smsg.msg_controllen = sizeof(cred_msg);
 389         size = recvmsg(conn->sock, &smsg, 0);
 390         if (size <  0) {
 391                 err(udev, "unable to receive ctrl message: %m\n");
 392                 goto err;
 393         }
 394         cmsg = CMSG_FIRSTHDR(&smsg);
 395         cred = (struct ucred *) CMSG_DATA(cmsg);
 396
 397         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 398                 err(udev, "no sender credentials received, message ignored\n");
 399                 goto err;
 400         }
 401
 402         if (cred->uid != 0) {
 403                 err(udev, "sender uid=%i, message ignored\n", cred->uid);
 404                 goto err;
 405         }
 406
 407         if (uctrl_msg->ctrl_msg_wire.magic != UDEV_CTRL_MAGIC) {
 408                 err(udev, "message magic 0x%08x doesn't match, ignore it\n", uctrl_msg->ctrl_msg_wire.magic);
 409                 goto err;
 410         }
 411
 412         dbg(udev, "created ctrl_msg %p (%i)\n", uctrl_msg, uctrl_msg->ctrl_msg_wire.type);
 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_ref(struct udev_ctrl_msg *ctrl_msg)
 420 {
 421         if (ctrl_msg == NULL)
 422                 return NULL;
 423         ctrl_msg->refcount++;
 424         return ctrl_msg;
 425 }
 426
 427 struct udev_ctrl_msg *udev_ctrl_msg_unref(struct udev_ctrl_msg *ctrl_msg)
 428 {
 429         if (ctrl_msg == NULL)
 430                 return NULL;
 431         ctrl_msg->refcount--;
 432         if (ctrl_msg->refcount > 0)
 433                 return ctrl_msg;
 434         dbg(ctrl_msg->conn->uctrl->udev, "release ctrl_msg %p\n", ctrl_msg);
 435         udev_ctrl_connection_unref(ctrl_msg->conn);
 436         free(ctrl_msg);
 437         return NULL;
 438 }
 439
 440 int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg)
 441 {
 442         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_LOG_LEVEL)
 443                 return ctrl_msg->ctrl_msg_wire.intval;
 444         return -1;
 445 }
 446
 447 int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 448 {
 449         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_STOP_EXEC_QUEUE)
 450                 return 1;
 451         return -1;
 452 }
 453
 454 int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 455 {
 456         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_START_EXEC_QUEUE)
 457                 return 1;
 458         return -1;
 459 }
 460
 461 int udev_ctrl_get_reload(struct udev_ctrl_msg *ctrl_msg)
 462 {
 463         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_RELOAD)
 464                 return 1;
 465         return -1;
 466 }
 467
 468 const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg)
 469 {
 470         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_ENV)
 471                 return ctrl_msg->ctrl_msg_wire.buf;
 472         return NULL;
 473 }
 474
 475 int udev_ctrl_get_set_children_max(struct udev_ctrl_msg *ctrl_msg)
 476 {
 477         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_CHILDREN_MAX)
 478                 return ctrl_msg->ctrl_msg_wire.intval;
 479         return -1;
 480 }
 481
 482 int udev_ctrl_get_ping(struct udev_ctrl_msg *ctrl_msg)
 483 {
 484         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_PING)
 485                 return 1;
 486         return -1;
 487 }
 488
 489 int udev_ctrl_get_exit(struct udev_ctrl_msg *ctrl_msg)
 490 {
 491         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_EXIT)
 492                 return 1;
 493         return -1;
 494 }