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 "udev.h"
  22
  23 /* wire protocol magic must match */
  24 #define UDEV_CTRL_MAGIC                                0xdead1dea
  25
  26 enum udev_ctrl_msg_type {
  27         UDEV_CTRL_UNKNOWN,
  28         UDEV_CTRL_SET_LOG_LEVEL,
  29         UDEV_CTRL_STOP_EXEC_QUEUE,
  30         UDEV_CTRL_START_EXEC_QUEUE,
  31         UDEV_CTRL_RELOAD,
  32         UDEV_CTRL_SET_ENV,
  33         UDEV_CTRL_SET_CHILDREN_MAX,
  34         UDEV_CTRL_PING,
  35         UDEV_CTRL_EXIT,
  36 };
  37
  38 struct udev_ctrl_msg_wire {
  39         char version[16];
  40         unsigned int magic;
  41         enum udev_ctrl_msg_type type;
  42         union {
  43                 int intval;
  44                 char buf[256];
  45         };
  46 };
  47
  48 struct udev_ctrl_msg {
  49         int refcount;
  50         struct udev_ctrl_connection *conn;
  51         struct udev_ctrl_msg_wire ctrl_msg_wire;
  52 };
  53
  54 struct udev_ctrl {
  55         int refcount;
  56         struct udev *udev;
  57         int sock;
  58         struct sockaddr_un saddr;
  59         socklen_t addrlen;
  60         bool bound;
  61         bool cleanup_socket;
  62         bool connected;
  63 };
  64
  65 struct udev_ctrl_connection {
  66         int refcount;
  67         struct udev_ctrl *uctrl;
  68         int sock;
  69 };
  70
  71 struct udev_ctrl *udev_ctrl_new_from_fd(struct udev *udev, int fd) {
  72         struct udev_ctrl *uctrl;
  73         const int on = 1;
  74         int r;
  75
  76         uctrl = new0(struct udev_ctrl, 1);
  77         if (uctrl == NULL)
  78                 return NULL;
  79         uctrl->refcount = 1;
  80         uctrl->udev = udev;
  81
  82         if (fd < 0) {
  83                 uctrl->sock = socket(AF_LOCAL, SOCK_SEQPACKET|SOCK_NONBLOCK|SOCK_CLOEXEC, 0);
  84                 if (uctrl->sock < 0) {
  85                         log_error_errno(errno, "error getting socket: %m");
  86                         udev_ctrl_unref(uctrl);
  87                         return NULL;
  88                 }
  89         } else {
  90                 uctrl->bound = true;
  91                 uctrl->sock = fd;
  92         }
  93         r = setsockopt(uctrl->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
  94         if (r < 0)
  95                 log_warning_errno(errno, "could not set SO_PASSCRED: %m");
  96
  97         uctrl->saddr.sun_family = AF_LOCAL;
  98         strscpy(uctrl->saddr.sun_path, sizeof(uctrl->saddr.sun_path), "/run/udev/control");
  99         uctrl->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(uctrl->saddr.sun_path);
 100         return uctrl;
 101 }
 102
 103 struct udev_ctrl *udev_ctrl_new(struct udev *udev) {
 104         return udev_ctrl_new_from_fd(udev, -1);
 105 }
 106
 107 int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl) {
 108         int err;
 109
 110         if (!uctrl->bound) {
 111                 err = bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 112                 if (err < 0 && errno == EADDRINUSE) {
 113                         unlink(uctrl->saddr.sun_path);
 114                         err = bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 115                 }
 116
 117                 if (err < 0) {
 118                         err = -errno;
 119                         log_error_errno(errno, "bind failed: %m");
 120                         return err;
 121                 }
 122
 123                 err = listen(uctrl->sock, 0);
 124                 if (err < 0) {
 125                         err = -errno;
 126                         log_error_errno(errno, "listen failed: %m");
 127                         return err;
 128                 }
 129
 130                 uctrl->bound = true;
 131                 uctrl->cleanup_socket = true;
 132         }
 133         return 0;
 134 }
 135
 136 struct udev *udev_ctrl_get_udev(struct udev_ctrl *uctrl) {
 137         return uctrl->udev;
 138 }
 139
 140 static struct udev_ctrl *udev_ctrl_ref(struct udev_ctrl *uctrl) {
 141         if (uctrl == NULL)
 142                 return NULL;
 143         uctrl->refcount++;
 144         return uctrl;
 145 }
 146
 147 struct udev_ctrl *udev_ctrl_unref(struct udev_ctrl *uctrl) {
 148         if (uctrl == NULL)
 149                 return NULL;
 150         uctrl->refcount--;
 151         if (uctrl->refcount > 0)
 152                 return uctrl;
 153         if (uctrl->sock >= 0)
 154                 close(uctrl->sock);
 155         free(uctrl);
 156         return NULL;
 157 }
 158
 159 int udev_ctrl_cleanup(struct udev_ctrl *uctrl) {
 160         if (uctrl == NULL)
 161                 return 0;
 162         if (uctrl->cleanup_socket)
 163                 unlink(uctrl->saddr.sun_path);
 164         return 0;
 165 }
 166
 167 int udev_ctrl_get_fd(struct udev_ctrl *uctrl) {
 168         if (uctrl == NULL)
 169                 return -EINVAL;
 170         return uctrl->sock;
 171 }
 172
 173 struct udev_ctrl_connection *udev_ctrl_get_connection(struct udev_ctrl *uctrl) {
 174         struct udev_ctrl_connection *conn;
 175         struct ucred ucred = {};
 176         const int on = 1;
 177         int r;
 178
 179         conn = new(struct udev_ctrl_connection, 1);
 180         if (conn == NULL)
 181                 return NULL;
 182         conn->refcount = 1;
 183         conn->uctrl = uctrl;
 184
 185         conn->sock = accept4(uctrl->sock, NULL, NULL, SOCK_CLOEXEC|SOCK_NONBLOCK);
 186         if (conn->sock < 0) {
 187                 if (errno != EINTR)
 188                         log_error_errno(errno, "unable to receive ctrl connection: %m");
 189                 goto err;
 190         }
 191
 192         /* check peer credential of connection */
 193         r = getpeercred(conn->sock, &ucred);
 194         if (r < 0) {
 195                 log_error_errno(r, "unable to receive credentials of ctrl connection: %m");
 196                 goto err;
 197         }
 198         if (ucred.uid > 0) {
 199                 log_error("sender uid="UID_FMT", message ignored", ucred.uid);
 200                 goto err;
 201         }
 202
 203         /* enable receiving of the sender credentials in the messages */
 204         r = setsockopt(conn->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 205         if (r < 0)
 206                 log_warning_errno(errno, "could not set SO_PASSCRED: %m");
 207
 208         udev_ctrl_ref(uctrl);
 209         return conn;
 210 err:
 211         if (conn->sock >= 0)
 212                 close(conn->sock);
 213         free(conn);
 214         return NULL;
 215 }
 216
 217 struct udev_ctrl_connection *udev_ctrl_connection_ref(struct udev_ctrl_connection *conn) {
 218         if (conn == NULL)
 219                 return NULL;
 220         conn->refcount++;
 221         return conn;
 222 }
 223
 224 struct udev_ctrl_connection *udev_ctrl_connection_unref(struct udev_ctrl_connection *conn) {
 225         if (conn == NULL)
 226                 return NULL;
 227         conn->refcount--;
 228         if (conn->refcount > 0)
 229                 return conn;
 230         if (conn->sock >= 0)
 231                 close(conn->sock);
 232         udev_ctrl_unref(conn->uctrl);
 233         free(conn);
 234         return NULL;
 235 }
 236
 237 static int ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf, int timeout) {
 238         struct udev_ctrl_msg_wire ctrl_msg_wire;
 239         int err = 0;
 240
 241         memzero(&ctrl_msg_wire, sizeof(struct udev_ctrl_msg_wire));
 242         strcpy(ctrl_msg_wire.version, "udev-" VERSION);
 243         ctrl_msg_wire.magic = UDEV_CTRL_MAGIC;
 244         ctrl_msg_wire.type = type;
 245
 246         if (buf != NULL)
 247                 strscpy(ctrl_msg_wire.buf, sizeof(ctrl_msg_wire.buf), buf);
 248         else
 249                 ctrl_msg_wire.intval = intval;
 250
 251         if (!uctrl->connected) {
 252                 if (connect(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen) < 0) {
 253                         err = -errno;
 254                         goto out;
 255                 }
 256                 uctrl->connected = true;
 257         }
 258         if (send(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0) < 0) {
 259                 err = -errno;
 260                 goto out;
 261         }
 262
 263         /* wait for peer message handling or disconnect */
 264         for (;;) {
 265                 struct pollfd pfd[1];
 266                 int r;
 267
 268                 pfd[0].fd = uctrl->sock;
 269                 pfd[0].events = POLLIN;
 270                 r = poll(pfd, 1, timeout * MSEC_PER_SEC);
 271                 if (r  < 0) {
 272                         if (errno == EINTR)
 273                                 continue;
 274                         err = -errno;
 275                         break;
 276                 }
 277
 278                 if (r > 0 && pfd[0].revents & POLLERR) {
 279                         err = -EIO;
 280                         break;
 281                 }
 282
 283                 if (r == 0)
 284                         err = -ETIMEDOUT;
 285                 break;
 286         }
 287 out:
 288         return err;
 289 }
 290
 291 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority, int timeout) {
 292         return ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL, timeout);
 293 }
 294
 295 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl, int timeout) {
 296         return ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL, timeout);
 297 }
 298
 299 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl, int timeout) {
 300         return ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL, timeout);
 301 }
 302
 303 int udev_ctrl_send_reload(struct udev_ctrl *uctrl, int timeout) {
 304         return ctrl_send(uctrl, UDEV_CTRL_RELOAD, 0, NULL, timeout);
 305 }
 306
 307 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key, int timeout) {
 308         return ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, key, timeout);
 309 }
 310
 311 int udev_ctrl_send_set_children_max(struct udev_ctrl *uctrl, int count, int timeout) {
 312         return ctrl_send(uctrl, UDEV_CTRL_SET_CHILDREN_MAX, count, NULL, timeout);
 313 }
 314
 315 int udev_ctrl_send_ping(struct udev_ctrl *uctrl, int timeout) {
 316         return ctrl_send(uctrl, UDEV_CTRL_PING, 0, NULL, timeout);
 317 }
 318
 319 int udev_ctrl_send_exit(struct udev_ctrl *uctrl, int timeout) {
 320         return ctrl_send(uctrl, UDEV_CTRL_EXIT, 0, NULL, timeout);
 321 }
 322
 323 struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl_connection *conn) {
 324         struct udev_ctrl_msg *uctrl_msg;
 325         ssize_t size;
 326         struct cmsghdr *cmsg;
 327         struct iovec iov;
 328         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 329         struct msghdr smsg = {
 330                 .msg_iov = &iov,
 331                 .msg_iovlen = 1,
 332                 .msg_control = cred_msg,
 333                 .msg_controllen = sizeof(cred_msg),
 334         };
 335         struct ucred *cred;
 336
 337         uctrl_msg = new0(struct udev_ctrl_msg, 1);
 338         if (uctrl_msg == NULL)
 339                 return NULL;
 340         uctrl_msg->refcount = 1;
 341         uctrl_msg->conn = conn;
 342         udev_ctrl_connection_ref(conn);
 343
 344         /* wait for the incoming message */
 345         for (;;) {
 346                 struct pollfd pfd[1];
 347                 int r;
 348
 349                 pfd[0].fd = conn->sock;
 350                 pfd[0].events = POLLIN;
 351
 352                 r = poll(pfd, 1, 10000);
 353                 if (r  < 0) {
 354                         if (errno == EINTR)
 355                                 continue;
 356                         goto err;
 357                 } else if (r == 0) {
 358                         log_error("timeout waiting for ctrl message");
 359                         goto err;
 360                 } else {
 361                         if (!(pfd[0].revents & POLLIN)) {
 362                                 log_error_errno(errno, "ctrl connection error: %m");
 363                                 goto err;
 364                         }
 365                 }
 366
 367                 break;
 368         }
 369
 370         iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 371         iov.iov_len = sizeof(struct udev_ctrl_msg_wire);
 372
 373         size = recvmsg(conn->sock, &smsg, 0);
 374         if (size <  0) {
 375                 log_error_errno(errno, "unable to receive ctrl message: %m");
 376                 goto err;
 377         }
 378
 379         cmsg_close_all(&smsg);
 380
 381         cmsg = CMSG_FIRSTHDR(&smsg);
 382         cred = (struct ucred *) CMSG_DATA(cmsg);
 383
 384         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 385                 log_error("no sender credentials received, message ignored");
 386                 goto err;
 387         }
 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 == NULL)
 407                 return NULL;
 408         ctrl_msg->refcount--;
 409         if (ctrl_msg->refcount > 0)
 410                 return ctrl_msg;
 411         udev_ctrl_connection_unref(ctrl_msg->conn);
 412         free(ctrl_msg);
 413         return NULL;
 414 }
 415
 416 int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg) {
 417         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_LOG_LEVEL)
 418                 return ctrl_msg->ctrl_msg_wire.intval;
 419         return -1;
 420 }
 421
 422 int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg) {
 423         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_STOP_EXEC_QUEUE)
 424                 return 1;
 425         return -1;
 426 }
 427
 428 int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg) {
 429         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_START_EXEC_QUEUE)
 430                 return 1;
 431         return -1;
 432 }
 433
 434 int udev_ctrl_get_reload(struct udev_ctrl_msg *ctrl_msg) {
 435         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_RELOAD)
 436                 return 1;
 437         return -1;
 438 }
 439
 440 const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg) {
 441         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_ENV)
 442                 return ctrl_msg->ctrl_msg_wire.buf;
 443         return NULL;
 444 }
 445
 446 int udev_ctrl_get_set_children_max(struct udev_ctrl_msg *ctrl_msg) {
 447         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_CHILDREN_MAX)
 448                 return ctrl_msg->ctrl_msg_wire.intval;
 449         return -1;
 450 }
 451
 452 int udev_ctrl_get_ping(struct udev_ctrl_msg *ctrl_msg) {
 453         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_PING)
 454                 return 1;
 455         return -1;
 456 }
 457
 458 int udev_ctrl_get_exit(struct udev_ctrl_msg *ctrl_msg) {
 459         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_EXIT)
 460                 return 1;
 461         return -1;
 462 }