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 <stdlib.h>
  14 #include <stddef.h>
  15 #include <string.h>
  16 #include <unistd.h>
  17 #include <poll.h>
  18 #include <sys/socket.h>
  19 #include <sys/un.h>
  20
  21 #include "socket-util.h"
  22 #include "formats-util.h"
  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         union sockaddr_union 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         int r;
  77
  78         uctrl = new0(struct udev_ctrl, 1);
  79         if (uctrl == NULL)
  80                 return NULL;
  81         uctrl->refcount = 1;
  82         uctrl->udev = udev;
  83
  84         if (fd < 0) {
  85                 uctrl->sock = socket(AF_LOCAL, SOCK_SEQPACKET|SOCK_NONBLOCK|SOCK_CLOEXEC, 0);
  86                 if (uctrl->sock < 0) {
  87                         log_error_errno(errno, "error getting socket: %m");
  88                         udev_ctrl_unref(uctrl);
  89                         return NULL;
  90                 }
  91         } else {
  92                 uctrl->bound = true;
  93                 uctrl->sock = fd;
  94         }
  95
  96         /*
  97          * FIXME: remove it as soon as we can depend on this:
  98          *   http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=90c6bd34f884cd9cee21f1d152baf6c18bcac949
  99          */
 100         r = setsockopt(uctrl->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 101         if (r < 0)
 102                 log_warning_errno(errno, "could not set SO_PASSCRED: %m");
 103
 104         uctrl->saddr.un.sun_family = AF_LOCAL;
 105         strscpy(uctrl->saddr.un.sun_path, sizeof(uctrl->saddr.un.sun_path), "/run/udev/control");
 106         uctrl->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(uctrl->saddr.un.sun_path);
 107         return uctrl;
 108 }
 109
 110 struct udev_ctrl *udev_ctrl_new(struct udev *udev) {
 111         return udev_ctrl_new_from_fd(udev, -1);
 112 }
 113
 114 int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl) {
 115         int err;
 116
 117         if (!uctrl->bound) {
 118                 err = bind(uctrl->sock, &uctrl->saddr.sa, uctrl->addrlen);
 119                 if (err < 0 && errno == EADDRINUSE) {
 120                         unlink(uctrl->saddr.un.sun_path);
 121                         err = bind(uctrl->sock, &uctrl->saddr.sa, uctrl->addrlen);
 122                 }
 123
 124                 if (err < 0)
 125                         return log_error_errno(errno, "bind failed: %m");
 126
 127                 err = listen(uctrl->sock, 0);
 128                 if (err < 0)
 129                         return log_error_errno(errno, "listen failed: %m");
 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         return uctrl->udev;
 139 }
 140
 141 static struct udev_ctrl *udev_ctrl_ref(struct udev_ctrl *uctrl) {
 142         if (uctrl)
 143                 uctrl->refcount++;
 144
 145         return uctrl;
 146 }
 147
 148 struct udev_ctrl *udev_ctrl_unref(struct udev_ctrl *uctrl) {
 149         if (uctrl && -- uctrl->refcount == 0) {
 150                 if (uctrl->sock >= 0)
 151                         close(uctrl->sock);
 152                 free(uctrl);
 153         }
 154
 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.un.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_errno(errno, "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_errno(r, "unable to receive credentials of ctrl connection: %m");
 195                 goto err;
 196         }
 197         if (ucred.uid > 0) {
 198                 log_error("sender uid="UID_FMT", message ignored", ucred.uid);
 199                 goto err;
 200         }
 201
 202         /* enable receiving of the sender credentials in the messages */
 203         r = setsockopt(conn->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 204         if (r < 0)
 205                 log_warning_errno(errno, "could not set SO_PASSCRED: %m");
 206
 207         udev_ctrl_ref(uctrl);
 208         return conn;
 209 err:
 210         if (conn->sock >= 0)
 211                 close(conn->sock);
 212         free(conn);
 213         return NULL;
 214 }
 215
 216 struct udev_ctrl_connection *udev_ctrl_connection_ref(struct udev_ctrl_connection *conn) {
 217         if (conn == NULL)
 218                 return NULL;
 219         conn->refcount++;
 220         return conn;
 221 }
 222
 223 struct udev_ctrl_connection *udev_ctrl_connection_unref(struct udev_ctrl_connection *conn) {
 224         if (conn && -- conn->refcount == 0) {
 225                 if (conn->sock >= 0)
 226                         close(conn->sock);
 227
 228                 udev_ctrl_unref(conn->uctrl);
 229
 230                 free(conn);
 231         }
 232
 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         struct udev_ctrl_msg_wire ctrl_msg_wire;
 238         int err = 0;
 239
 240         memzero(&ctrl_msg_wire, sizeof(struct udev_ctrl_msg_wire));
 241         strcpy(ctrl_msg_wire.version, "udev-" VERSION);
 242         ctrl_msg_wire.magic = UDEV_CTRL_MAGIC;
 243         ctrl_msg_wire.type = type;
 244
 245         if (buf != NULL)
 246                 strscpy(ctrl_msg_wire.buf, sizeof(ctrl_msg_wire.buf), buf);
 247         else
 248                 ctrl_msg_wire.intval = intval;
 249
 250         if (!uctrl->connected) {
 251                 if (connect(uctrl->sock, &uctrl->saddr.sa, uctrl->addrlen) < 0) {
 252                         err = -errno;
 253                         goto out;
 254                 }
 255                 uctrl->connected = true;
 256         }
 257         if (send(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0) < 0) {
 258                 err = -errno;
 259                 goto out;
 260         }
 261
 262         /* wait for peer message handling or disconnect */
 263         for (;;) {
 264                 struct pollfd pfd[1];
 265                 int r;
 266
 267                 pfd[0].fd = uctrl->sock;
 268                 pfd[0].events = POLLIN;
 269                 r = poll(pfd, 1, timeout * MSEC_PER_SEC);
 270                 if (r  < 0) {
 271                         if (errno == EINTR)
 272                                 continue;
 273                         err = -errno;
 274                         break;
 275                 }
 276
 277                 if (r > 0 && pfd[0].revents & POLLERR) {
 278                         err = -EIO;
 279                         break;
 280                 }
 281
 282                 if (r == 0)
 283                         err = -ETIMEDOUT;
 284                 break;
 285         }
 286 out:
 287         return err;
 288 }
 289
 290 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority, int timeout) {
 291         return ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL, timeout);
 292 }
 293
 294 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl, int timeout) {
 295         return ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL, timeout);
 296 }
 297
 298 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl, int timeout) {
 299         return ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL, timeout);
 300 }
 301
 302 int udev_ctrl_send_reload(struct udev_ctrl *uctrl, int timeout) {
 303         return ctrl_send(uctrl, UDEV_CTRL_RELOAD, 0, NULL, timeout);
 304 }
 305
 306 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key, int timeout) {
 307         return ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, key, timeout);
 308 }
 309
 310 int udev_ctrl_send_set_children_max(struct udev_ctrl *uctrl, int count, int timeout) {
 311         return ctrl_send(uctrl, UDEV_CTRL_SET_CHILDREN_MAX, count, NULL, timeout);
 312 }
 313
 314 int udev_ctrl_send_ping(struct udev_ctrl *uctrl, int timeout) {
 315         return ctrl_send(uctrl, UDEV_CTRL_PING, 0, NULL, timeout);
 316 }
 317
 318 int udev_ctrl_send_exit(struct udev_ctrl *uctrl, int timeout) {
 319         return ctrl_send(uctrl, UDEV_CTRL_EXIT, 0, NULL, timeout);
 320 }
 321
 322 struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl_connection *conn) {
 323         struct udev_ctrl_msg *uctrl_msg;
 324         ssize_t size;
 325         struct cmsghdr *cmsg;
 326         struct iovec iov;
 327         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 328         struct msghdr smsg = {
 329                 .msg_iov = &iov,
 330                 .msg_iovlen = 1,
 331                 .msg_control = cred_msg,
 332                 .msg_controllen = sizeof(cred_msg),
 333         };
 334         struct ucred *cred;
 335
 336         uctrl_msg = new0(struct udev_ctrl_msg, 1);
 337         if (uctrl_msg == NULL)
 338                 return NULL;
 339         uctrl_msg->refcount = 1;
 340         uctrl_msg->conn = conn;
 341         udev_ctrl_connection_ref(conn);
 342
 343         /* wait for the incoming message */
 344         for (;;) {
 345                 struct pollfd pfd[1];
 346                 int r;
 347
 348                 pfd[0].fd = conn->sock;
 349                 pfd[0].events = POLLIN;
 350
 351                 r = poll(pfd, 1, 10000);
 352                 if (r  < 0) {
 353                         if (errno == EINTR)
 354                                 continue;
 355                         goto err;
 356                 } else if (r == 0) {
 357                         log_error("timeout waiting for ctrl message");
 358                         goto err;
 359                 } else {
 360                         if (!(pfd[0].revents & POLLIN)) {
 361                                 log_error_errno(errno, "ctrl connection error: %m");
 362                                 goto err;
 363                         }
 364                 }
 365
 366                 break;
 367         }
 368
 369         iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 370         iov.iov_len = sizeof(struct udev_ctrl_msg_wire);
 371
 372         size = recvmsg(conn->sock, &smsg, 0);
 373         if (size <  0) {
 374                 log_error_errno(errno, "unable to receive ctrl message: %m");
 375                 goto err;
 376         }
 377
 378         cmsg_close_all(&smsg);
 379
 380         cmsg = CMSG_FIRSTHDR(&smsg);
 381
 382         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 383                 log_error("no sender credentials received, message ignored");
 384                 goto err;
 385         }
 386
 387         cred = (struct ucred *) CMSG_DATA(cmsg);
 388
 389         if (cred->uid != 0) {
 390                 log_error("sender uid="UID_FMT", message ignored", cred->uid);
 391                 goto err;
 392         }
 393
 394         if (uctrl_msg->ctrl_msg_wire.magic != UDEV_CTRL_MAGIC) {
 395                 log_error("message magic 0x%08x doesn't match, ignore it", uctrl_msg->ctrl_msg_wire.magic);
 396                 goto err;
 397         }
 398
 399         return uctrl_msg;
 400 err:
 401         udev_ctrl_msg_unref(uctrl_msg);
 402         return NULL;
 403 }
 404
 405 struct udev_ctrl_msg *udev_ctrl_msg_unref(struct udev_ctrl_msg *ctrl_msg) {
 406         if (ctrl_msg && -- ctrl_msg->refcount == 0) {
 407                 udev_ctrl_connection_unref(ctrl_msg->conn);
 408                 free(ctrl_msg);
 409         }
 410
 411         return NULL;
 412 }
 413
 414 int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg) {
 415         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_LOG_LEVEL)
 416                 return ctrl_msg->ctrl_msg_wire.intval;
 417         return -1;
 418 }
 419
 420 int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg) {
 421         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_STOP_EXEC_QUEUE)
 422                 return 1;
 423         return -1;
 424 }
 425
 426 int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg) {
 427         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_START_EXEC_QUEUE)
 428                 return 1;
 429         return -1;
 430 }
 431
 432 int udev_ctrl_get_reload(struct udev_ctrl_msg *ctrl_msg) {
 433         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_RELOAD)
 434                 return 1;
 435         return -1;
 436 }
 437
 438 const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg) {
 439         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_ENV)
 440                 return ctrl_msg->ctrl_msg_wire.buf;
 441         return NULL;
 442 }
 443
 444 int udev_ctrl_get_set_children_max(struct udev_ctrl_msg *ctrl_msg) {
 445         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_CHILDREN_MAX)
 446                 return ctrl_msg->ctrl_msg_wire.intval;
 447         return -1;
 448 }
 449
 450 int udev_ctrl_get_ping(struct udev_ctrl_msg *ctrl_msg) {
 451         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_PING)
 452                 return 1;
 453         return -1;
 454 }
 455
 456 int udev_ctrl_get_exit(struct udev_ctrl_msg *ctrl_msg) {
 457         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_EXIT)
 458                 return 1;
 459         return -1;
 460 }