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         struct udev_ctrl *uctrl;
  75         const int on = 1;
  76
  77         uctrl = new0(struct udev_ctrl, 1);
  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");
  87                         udev_ctrl_unref(uctrl);
  88                         return NULL;
  89                 }
  90         } else {
  91                 uctrl->bound = true;
  92                 uctrl->sock = fd;
  93         }
  94         setsockopt(uctrl->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
  95
  96         uctrl->saddr.sun_family = AF_LOCAL;
  97         strscpy(uctrl->saddr.sun_path, sizeof(uctrl->saddr.sun_path), "/run/udev/control");
  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         return udev_ctrl_new_from_fd(udev, -1);
 104 }
 105
 106 int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl) {
 107         int err;
 108
 109         if (!uctrl->bound) {
 110                 err = bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 111                 if (err < 0 && errno == EADDRINUSE) {
 112                         unlink(uctrl->saddr.sun_path);
 113                         err = bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 114                 }
 115
 116                 if (err < 0) {
 117                         err = -errno;
 118                         log_error("bind failed: %m");
 119                         return err;
 120                 }
 121
 122                 err = listen(uctrl->sock, 0);
 123                 if (err < 0) {
 124                         err = -errno;
 125                         log_error("listen failed: %m");
 126                         return err;
 127                 }
 128
 129                 uctrl->bound = true;
 130                 uctrl->cleanup_socket = true;
 131         }
 132         return 0;
 133 }
 134
 135 struct udev *udev_ctrl_get_udev(struct udev_ctrl *uctrl) {
 136         return uctrl->udev;
 137 }
 138
 139 static struct udev_ctrl *udev_ctrl_ref(struct udev_ctrl *uctrl) {
 140         if (uctrl == NULL)
 141                 return NULL;
 142         uctrl->refcount++;
 143         return uctrl;
 144 }
 145
 146 struct udev_ctrl *udev_ctrl_unref(struct udev_ctrl *uctrl) {
 147         if (uctrl == NULL)
 148                 return NULL;
 149         uctrl->refcount--;
 150         if (uctrl->refcount > 0)
 151                 return uctrl;
 152         if (uctrl->sock >= 0)
 153                 close(uctrl->sock);
 154         free(uctrl);
 155         return NULL;
 156 }
 157
 158 int udev_ctrl_cleanup(struct udev_ctrl *uctrl) {
 159         if (uctrl == NULL)
 160                 return 0;
 161         if (uctrl->cleanup_socket)
 162                 unlink(uctrl->saddr.sun_path);
 163         return 0;
 164 }
 165
 166 int udev_ctrl_get_fd(struct udev_ctrl *uctrl) {
 167         if (uctrl == NULL)
 168                 return -EINVAL;
 169         return uctrl->sock;
 170 }
 171
 172 struct udev_ctrl_connection *udev_ctrl_get_connection(struct udev_ctrl *uctrl) {
 173         struct udev_ctrl_connection *conn;
 174         struct ucred ucred = {};
 175         const int on = 1;
 176         int r;
 177
 178         conn = new(struct udev_ctrl_connection, 1);
 179         if (conn == NULL)
 180                 return NULL;
 181         conn->refcount = 1;
 182         conn->uctrl = uctrl;
 183
 184         conn->sock = accept4(uctrl->sock, NULL, NULL, SOCK_CLOEXEC|SOCK_NONBLOCK);
 185         if (conn->sock < 0) {
 186                 if (errno != EINTR)
 187                         log_error("unable to receive ctrl connection: %m");
 188                 goto err;
 189         }
 190
 191         /* check peer credential of connection */
 192         r = getpeercred(conn->sock, &ucred);
 193         if (r < 0) {
 194                 log_error("unable to receive credentials of ctrl connection: %s", strerror(-r));
 195                 goto err;
 196         }
 197         if (ucred.uid > 0) {
 198                 log_error("sender uid=%i, message ignored", ucred.uid);
 199                 goto err;
 200         }
 201
 202         /* enable receiving of the sender credentials in the messages */
 203         setsockopt(conn->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 204         udev_ctrl_ref(uctrl);
 205         return conn;
 206 err:
 207         if (conn->sock >= 0)
 208                 close(conn->sock);
 209         free(conn);
 210         return NULL;
 211 }
 212
 213 struct udev_ctrl_connection *udev_ctrl_connection_ref(struct udev_ctrl_connection *conn) {
 214         if (conn == NULL)
 215                 return NULL;
 216         conn->refcount++;
 217         return conn;
 218 }
 219
 220 struct udev_ctrl_connection *udev_ctrl_connection_unref(struct udev_ctrl_connection *conn) {
 221         if (conn == NULL)
 222                 return NULL;
 223         conn->refcount--;
 224         if (conn->refcount > 0)
 225                 return conn;
 226         if (conn->sock >= 0)
 227                 close(conn->sock);
 228         udev_ctrl_unref(conn->uctrl);
 229         free(conn);
 230         return NULL;
 231 }
 232
 233 static int ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf, int timeout) {
 234         struct udev_ctrl_msg_wire ctrl_msg_wire;
 235         int err = 0;
 236
 237         memzero(&ctrl_msg_wire, sizeof(struct udev_ctrl_msg_wire));
 238         strcpy(ctrl_msg_wire.version, "udev-" VERSION);
 239         ctrl_msg_wire.magic = UDEV_CTRL_MAGIC;
 240         ctrl_msg_wire.type = type;
 241
 242         if (buf != NULL)
 243                 strscpy(ctrl_msg_wire.buf, sizeof(ctrl_msg_wire.buf), buf);
 244         else
 245                 ctrl_msg_wire.intval = intval;
 246
 247         if (!uctrl->connected) {
 248                 if (connect(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen) < 0) {
 249                         err = -errno;
 250                         goto out;
 251                 }
 252                 uctrl->connected = true;
 253         }
 254         if (send(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0) < 0) {
 255                 err = -errno;
 256                 goto out;
 257         }
 258
 259         /* wait for peer message handling or disconnect */
 260         for (;;) {
 261                 struct pollfd pfd[1];
 262                 int r;
 263
 264                 pfd[0].fd = uctrl->sock;
 265                 pfd[0].events = POLLIN;
 266                 r = poll(pfd, 1, timeout * MSEC_PER_SEC);
 267                 if (r  < 0) {
 268                         if (errno == EINTR)
 269                                 continue;
 270                         err = -errno;
 271                         break;
 272                 }
 273
 274                 if (r > 0 && pfd[0].revents & POLLERR) {
 275                         err = -EIO;
 276                         break;
 277                 }
 278
 279                 if (r == 0)
 280                         err = -ETIMEDOUT;
 281                 break;
 282         }
 283 out:
 284         return err;
 285 }
 286
 287 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority, int timeout) {
 288         return ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL, timeout);
 289 }
 290
 291 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl, int timeout) {
 292         return ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL, timeout);
 293 }
 294
 295 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl, int timeout) {
 296         return ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL, timeout);
 297 }
 298
 299 int udev_ctrl_send_reload(struct udev_ctrl *uctrl, int timeout) {
 300         return ctrl_send(uctrl, UDEV_CTRL_RELOAD, 0, NULL, timeout);
 301 }
 302
 303 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key, int timeout) {
 304         return ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, key, timeout);
 305 }
 306
 307 int udev_ctrl_send_set_children_max(struct udev_ctrl *uctrl, int count, int timeout) {
 308         return ctrl_send(uctrl, UDEV_CTRL_SET_CHILDREN_MAX, count, NULL, timeout);
 309 }
 310
 311 int udev_ctrl_send_ping(struct udev_ctrl *uctrl, int timeout) {
 312         return ctrl_send(uctrl, UDEV_CTRL_PING, 0, NULL, timeout);
 313 }
 314
 315 int udev_ctrl_send_exit(struct udev_ctrl *uctrl, int timeout) {
 316         return ctrl_send(uctrl, UDEV_CTRL_EXIT, 0, NULL, timeout);
 317 }
 318
 319 struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl_connection *conn) {
 320         struct udev_ctrl_msg *uctrl_msg;
 321         ssize_t size;
 322         struct cmsghdr *cmsg;
 323         struct iovec iov;
 324         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 325         struct msghdr smsg = {
 326                 .msg_iov = &iov,
 327                 .msg_iovlen = 1,
 328                 .msg_control = cred_msg,
 329                 .msg_controllen = sizeof(cred_msg),
 330         };
 331         struct ucred *cred;
 332
 333         uctrl_msg = new0(struct udev_ctrl_msg, 1);
 334         if (uctrl_msg == NULL)
 335                 return NULL;
 336         uctrl_msg->refcount = 1;
 337         uctrl_msg->conn = conn;
 338         udev_ctrl_connection_ref(conn);
 339
 340         /* wait for the incoming message */
 341         for (;;) {
 342                 struct pollfd pfd[1];
 343                 int r;
 344
 345                 pfd[0].fd = conn->sock;
 346                 pfd[0].events = POLLIN;
 347
 348                 r = poll(pfd, 1, 10000);
 349                 if (r  < 0) {
 350                         if (errno == EINTR)
 351                                 continue;
 352                         goto err;
 353                 } else if (r == 0) {
 354                         log_error("timeout waiting for ctrl message");
 355                         goto err;
 356                 } else {
 357                         if (!(pfd[0].revents & POLLIN)) {
 358                                 log_error("ctrl connection error: %m");
 359                                 goto err;
 360                         }
 361                 }
 362
 363                 break;
 364         }
 365
 366         iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 367         iov.iov_len = sizeof(struct udev_ctrl_msg_wire);
 368
 369         size = recvmsg(conn->sock, &smsg, 0);
 370         if (size <  0) {
 371                 log_error("unable to receive ctrl message: %m");
 372                 goto err;
 373         }
 374         cmsg = CMSG_FIRSTHDR(&smsg);
 375         cred = (struct ucred *) CMSG_DATA(cmsg);
 376
 377         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 378                 log_error("no sender credentials received, message ignored");
 379                 goto err;
 380         }
 381
 382         if (cred->uid != 0) {
 383                 log_error("sender uid=%i, message ignored", cred->uid);
 384                 goto err;
 385         }
 386
 387         if (uctrl_msg->ctrl_msg_wire.magic != UDEV_CTRL_MAGIC) {
 388                 log_error("message magic 0x%08x doesn't match, ignore it", uctrl_msg->ctrl_msg_wire.magic);
 389                 goto err;
 390         }
 391
 392         return uctrl_msg;
 393 err:
 394         udev_ctrl_msg_unref(uctrl_msg);
 395         return NULL;
 396 }
 397
 398 struct udev_ctrl_msg *udev_ctrl_msg_unref(struct udev_ctrl_msg *ctrl_msg) {
 399         if (ctrl_msg == NULL)
 400                 return NULL;
 401         ctrl_msg->refcount--;
 402         if (ctrl_msg->refcount > 0)
 403                 return ctrl_msg;
 404         udev_ctrl_connection_unref(ctrl_msg->conn);
 405         free(ctrl_msg);
 406         return NULL;
 407 }
 408
 409 int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg) {
 410         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_LOG_LEVEL)
 411                 return ctrl_msg->ctrl_msg_wire.intval;
 412         return -1;
 413 }
 414
 415 int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg) {
 416         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_STOP_EXEC_QUEUE)
 417                 return 1;
 418         return -1;
 419 }
 420
 421 int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg) {
 422         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_START_EXEC_QUEUE)
 423                 return 1;
 424         return -1;
 425 }
 426
 427 int udev_ctrl_get_reload(struct udev_ctrl_msg *ctrl_msg) {
 428         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_RELOAD)
 429                 return 1;
 430         return -1;
 431 }
 432
 433 const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg) {
 434         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_ENV)
 435                 return ctrl_msg->ctrl_msg_wire.buf;
 436         return NULL;
 437 }
 438
 439 int udev_ctrl_get_set_children_max(struct udev_ctrl_msg *ctrl_msg) {
 440         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_CHILDREN_MAX)
 441                 return ctrl_msg->ctrl_msg_wire.intval;
 442         return -1;
 443 }
 444
 445 int udev_ctrl_get_ping(struct udev_ctrl_msg *ctrl_msg) {
 446         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_PING)
 447                 return 1;
 448         return -1;
 449 }
 450
 451 int udev_ctrl_get_exit(struct udev_ctrl_msg *ctrl_msg) {
 452         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_EXIT)
 453                 return 1;
 454         return -1;
 455 }