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                         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         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                         log_error("bind failed: %m\n");
 121                         return err;
 122                 }
 123
 124                 err = listen(uctrl->sock, 0);
 125                 if (err < 0) {
 126                         err = -errno;
 127                         log_error("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                         log_error("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                 log_error("unable to receive credentials of ctrl connection: %m\n");
 203                 goto err;
 204         }
 205         if (ucred.uid > 0) {
 206                 log_error("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_ctrl_msg *uctrl_msg;
 341         ssize_t size;
 342         struct msghdr smsg;
 343         struct cmsghdr *cmsg;
 344         struct iovec iov;
 345         struct ucred *cred;
 346         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 347
 348         uctrl_msg = calloc(1, sizeof(struct udev_ctrl_msg));
 349         if (uctrl_msg == NULL)
 350                 return NULL;
 351         uctrl_msg->refcount = 1;
 352         uctrl_msg->conn = conn;
 353         udev_ctrl_connection_ref(conn);
 354
 355         /* wait for the incoming message */
 356         for(;;) {
 357                 struct pollfd pfd[1];
 358                 int r;
 359
 360                 pfd[0].fd = conn->sock;
 361                 pfd[0].events = POLLIN;
 362
 363                 r = poll(pfd, 1, 10000);
 364                 if (r  < 0) {
 365                         if (errno == EINTR)
 366                                 continue;
 367                         goto err;
 368                 } else if (r == 0) {
 369                         log_error("timeout waiting for ctrl message\n");
 370                         goto err;
 371                 } else {
 372                         if (!(pfd[0].revents & POLLIN)) {
 373                                 log_error("ctrl connection error: %m\n");
 374                                 goto err;
 375                         }
 376                 }
 377
 378                 break;
 379         }
 380
 381         iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 382         iov.iov_len = sizeof(struct udev_ctrl_msg_wire);
 383         memset(&smsg, 0x00, sizeof(struct msghdr));
 384         smsg.msg_iov = &iov;
 385         smsg.msg_iovlen = 1;
 386         smsg.msg_control = cred_msg;
 387         smsg.msg_controllen = sizeof(cred_msg);
 388         size = recvmsg(conn->sock, &smsg, 0);
 389         if (size <  0) {
 390                 log_error("unable to receive ctrl message: %m\n");
 391                 goto err;
 392         }
 393         cmsg = CMSG_FIRSTHDR(&smsg);
 394         cred = (struct ucred *) CMSG_DATA(cmsg);
 395
 396         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 397                 log_error("no sender credentials received, message ignored\n");
 398                 goto err;
 399         }
 400
 401         if (cred->uid != 0) {
 402                 log_error("sender uid=%i, message ignored\n", cred->uid);
 403                 goto err;
 404         }
 405
 406         if (uctrl_msg->ctrl_msg_wire.magic != UDEV_CTRL_MAGIC) {
 407                 log_error("message magic 0x%08x doesn't match, ignore it\n", uctrl_msg->ctrl_msg_wire.magic);
 408                 goto err;
 409         }
 410
 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         udev_ctrl_connection_unref(ctrl_msg->conn);
 433         free(ctrl_msg);
 434         return NULL;
 435 }
 436
 437 int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg)
 438 {
 439         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_LOG_LEVEL)
 440                 return ctrl_msg->ctrl_msg_wire.intval;
 441         return -1;
 442 }
 443
 444 int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 445 {
 446         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_STOP_EXEC_QUEUE)
 447                 return 1;
 448         return -1;
 449 }
 450
 451 int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 452 {
 453         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_START_EXEC_QUEUE)
 454                 return 1;
 455         return -1;
 456 }
 457
 458 int udev_ctrl_get_reload(struct udev_ctrl_msg *ctrl_msg)
 459 {
 460         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_RELOAD)
 461                 return 1;
 462         return -1;
 463 }
 464
 465 const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg)
 466 {
 467         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_ENV)
 468                 return ctrl_msg->ctrl_msg_wire.buf;
 469         return NULL;
 470 }
 471
 472 int udev_ctrl_get_set_children_max(struct udev_ctrl_msg *ctrl_msg)
 473 {
 474         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_CHILDREN_MAX)
 475                 return ctrl_msg->ctrl_msg_wire.intval;
 476         return -1;
 477 }
 478
 479 int udev_ctrl_get_ping(struct udev_ctrl_msg *ctrl_msg)
 480 {
 481         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_PING)
 482                 return 1;
 483         return -1;
 484 }
 485
 486 int udev_ctrl_get_exit(struct udev_ctrl_msg *ctrl_msg)
 487 {
 488         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_EXIT)
 489                 return 1;
 490         return -1;
 491 }