libudev/libudev-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 "libudev.h"
  24 #include "libudev-private.h"
  25
  26 /* wire protocol magic must match */
  27 #define UDEV_CTRL_MAGIC                         0xdead1dea
  28
  29 enum udev_ctrl_msg_type {
  30         UDEV_CTRL_UNKNOWN,
  31         UDEV_CTRL_SET_LOG_LEVEL,
  32         UDEV_CTRL_STOP_EXEC_QUEUE,
  33         UDEV_CTRL_START_EXEC_QUEUE,
  34         UDEV_CTRL_RELOAD_RULES,
  35         UDEV_CTRL_SET_ENV,
  36         UDEV_CTRL_SET_CHILDREN_MAX,
  37         UDEV_CTRL_PING,
  38         UDEV_CTRL_EXIT,
  39 };
  40
  41 struct udev_ctrl_msg_wire {
  42         char version[16];
  43         unsigned int magic;
  44         enum udev_ctrl_msg_type type;
  45         union {
  46                 int intval;
  47                 char buf[256];
  48         };
  49 };
  50
  51 struct udev_ctrl_msg {
  52         int refcount;
  53         struct udev_ctrl_connection *conn;
  54         struct udev_ctrl_msg_wire ctrl_msg_wire;
  55 };
  56
  57 struct udev_ctrl {
  58         int refcount;
  59         struct udev *udev;
  60         int sock;
  61         struct sockaddr_un saddr;
  62         socklen_t addrlen;
  63         bool bound;
  64         bool connected;
  65 };
  66
  67 struct udev_ctrl_connection {
  68         int refcount;
  69         struct udev_ctrl *uctrl;
  70         int sock;
  71 };
  72
  73 static struct udev_ctrl *udev_ctrl_new(struct udev *udev)
  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         return uctrl;
  83 }
  84
  85 struct udev_ctrl *udev_ctrl_new_from_socket_fd(struct udev *udev, const char *socket_path, int fd)
  86 {
  87         struct udev_ctrl *uctrl;
  88
  89         uctrl = udev_ctrl_new(udev);
  90         if (uctrl == NULL)
  91                 return NULL;
  92
  93         if (fd < 0) {
  94                 uctrl->sock = socket(AF_LOCAL, SOCK_SEQPACKET|SOCK_NONBLOCK|SOCK_CLOEXEC, 0);
  95                 if (uctrl->sock < 0) {
  96                         err(udev, "error getting socket: %m\n");
  97                         udev_ctrl_unref(uctrl);
  98                         return NULL;
  99                 }
 100         } else {
 101                 uctrl->bound = true;
 102                 uctrl->sock = fd;
 103         }
 104
 105         uctrl->saddr.sun_family = AF_LOCAL;
 106         strcpy(uctrl->saddr.sun_path, socket_path);
 107         uctrl->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(uctrl->saddr.sun_path);
 108         /* translate leading '@' to abstract namespace */
 109         if (uctrl->saddr.sun_path[0] == '@')
 110                 uctrl->saddr.sun_path[0] = '\0';
 111         return uctrl;
 112 }
 113
 114 struct udev_ctrl *udev_ctrl_new_from_socket(struct udev *udev, const char *socket_path)
 115 {
 116         return udev_ctrl_new_from_socket_fd(udev, socket_path, -1);
 117 }
 118
 119 int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl)
 120 {
 121         int err;
 122
 123         if (!uctrl->bound) {
 124                 err = bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 125                 if (err < 0) {
 126                         err = -errno;
 127                         err(uctrl->udev, "bind failed: %m\n");
 128                         return err;
 129                 }
 130
 131                 err = listen(uctrl->sock, 0);
 132                 if (err < 0) {
 133                         err = -errno;
 134                         err(uctrl->udev, "listen failed: %m\n");
 135                         return err;
 136                 }
 137
 138                 uctrl->bound = true;
 139         }
 140         return 0;
 141 }
 142
 143 struct udev *udev_ctrl_get_udev(struct udev_ctrl *uctrl)
 144 {
 145         return uctrl->udev;
 146 }
 147
 148 struct udev_ctrl *udev_ctrl_ref(struct udev_ctrl *uctrl)
 149 {
 150         if (uctrl == NULL)
 151                 return NULL;
 152         uctrl->refcount++;
 153         return uctrl;
 154 }
 155
 156 struct udev_ctrl *udev_ctrl_unref(struct udev_ctrl *uctrl)
 157 {
 158         if (uctrl == NULL)
 159                 return NULL;
 160         uctrl->refcount--;
 161         if (uctrl->refcount > 0)
 162                 return uctrl;
 163         if (uctrl->sock >= 0)
 164                 close(uctrl->sock);
 165         free(uctrl);
 166         return NULL;
 167 }
 168
 169 int udev_ctrl_get_fd(struct udev_ctrl *uctrl)
 170 {
 171         if (uctrl == NULL)
 172                 return -1;
 173         return uctrl->sock;
 174 }
 175
 176 struct udev_ctrl_connection *udev_ctrl_get_connection(struct udev_ctrl *uctrl)
 177 {
 178         struct udev_ctrl_connection *conn;
 179         const int on = 1;
 180
 181         conn = calloc(1, sizeof(struct udev_ctrl_connection));
 182         if (conn == NULL)
 183                 return NULL;
 184         conn->refcount = 1;
 185         conn->uctrl = uctrl;
 186
 187         conn->sock = accept4(uctrl->sock, NULL, NULL, SOCK_CLOEXEC);
 188         if (conn->sock < 0) {
 189                 free(conn);
 190                 return NULL;
 191         }
 192
 193         /* enable receiving of the sender credentials */
 194         setsockopt(conn->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 195         udev_ctrl_ref(uctrl);
 196         return conn;
 197 }
 198
 199 struct udev_ctrl_connection *udev_ctrl_connection_ref(struct udev_ctrl_connection *conn)
 200 {
 201         if (conn == NULL)
 202                 return NULL;
 203         conn->refcount++;
 204         return conn;
 205 }
 206
 207 struct udev_ctrl_connection *udev_ctrl_connection_unref(struct udev_ctrl_connection *conn)
 208 {
 209         if (conn == NULL)
 210                 return NULL;
 211         conn->refcount--;
 212         if (conn->refcount > 0)
 213                 return conn;
 214         if (conn->sock >= 0)
 215                 close(conn->sock);
 216         udev_ctrl_unref(conn->uctrl);
 217         free(conn);
 218         return NULL;
 219 }
 220
 221 static int ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf, int timeout)
 222 {
 223         struct udev_ctrl_msg_wire ctrl_msg_wire;
 224         int err = 0;
 225
 226         memset(&ctrl_msg_wire, 0x00, sizeof(struct udev_ctrl_msg_wire));
 227         strcpy(ctrl_msg_wire.version, "udev-" VERSION);
 228         ctrl_msg_wire.magic = UDEV_CTRL_MAGIC;
 229         ctrl_msg_wire.type = type;
 230
 231         if (buf != NULL)
 232                 util_strscpy(ctrl_msg_wire.buf, sizeof(ctrl_msg_wire.buf), buf);
 233         else
 234                 ctrl_msg_wire.intval = intval;
 235
 236         if (!uctrl->connected) {
 237                 if (connect(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen) < 0) {
 238                         err = -errno;
 239                         goto out;
 240                 }
 241                 uctrl->connected = true;
 242         }
 243         if (send(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0) < 0) {
 244                 err = -errno;
 245                 goto out;
 246         }
 247
 248         /* wait for peer message handling or disconnect */
 249         for (;;) {
 250                 struct pollfd pfd[1];
 251                 int r;
 252
 253                 pfd[0].fd = uctrl->sock;
 254                 pfd[0].events = POLLIN;
 255                 r = poll(pfd, 1, timeout * 1000);
 256                 if (r  < 0) {
 257                         if (errno == EINTR)
 258                                 continue;
 259                         err = -errno;
 260                         break;
 261                 }
 262
 263                 if (r > 0 && pfd[0].revents & POLLERR) {
 264                         err = -EIO;
 265                         break;
 266                 }
 267
 268                 if (r == 0)
 269                         err = -ETIMEDOUT;
 270                 break;
 271         }
 272 out:
 273         return err;
 274 }
 275
 276 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority, int timeout)
 277 {
 278         return ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL, timeout);
 279 }
 280
 281 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl, int timeout)
 282 {
 283         return ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL, timeout);
 284 }
 285
 286 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl, int timeout)
 287 {
 288         return ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL, timeout);
 289 }
 290
 291 int udev_ctrl_send_reload_rules(struct udev_ctrl *uctrl, int timeout)
 292 {
 293         return ctrl_send(uctrl, UDEV_CTRL_RELOAD_RULES, 0, NULL, timeout);
 294 }
 295
 296 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key, int timeout)
 297 {
 298         return ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, key, timeout);
 299 }
 300
 301 int udev_ctrl_send_set_children_max(struct udev_ctrl *uctrl, int count, int timeout)
 302 {
 303         return ctrl_send(uctrl, UDEV_CTRL_SET_CHILDREN_MAX, count, NULL, timeout);
 304 }
 305
 306 int udev_ctrl_send_ping(struct udev_ctrl *uctrl, int timeout)
 307 {
 308         return ctrl_send(uctrl, UDEV_CTRL_PING, 0, NULL, timeout);
 309 }
 310
 311 int udev_ctrl_send_exit(struct udev_ctrl *uctrl, int timeout)
 312 {
 313         return ctrl_send(uctrl, UDEV_CTRL_EXIT, 0, NULL, timeout);
 314 }
 315
 316 struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl_connection *conn)
 317 {
 318         struct udev *udev = conn->uctrl->udev;
 319         struct udev_ctrl_msg *uctrl_msg;
 320         ssize_t size;
 321         struct msghdr smsg;
 322         struct cmsghdr *cmsg;
 323         struct iovec iov;
 324         struct ucred *cred;
 325         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 326
 327         uctrl_msg = calloc(1, sizeof(struct udev_ctrl_msg));
 328         if (uctrl_msg == NULL)
 329                 return NULL;
 330         uctrl_msg->refcount = 1;
 331         uctrl_msg->conn = conn;
 332         udev_ctrl_connection_ref(conn);
 333
 334         iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 335         iov.iov_len = sizeof(struct udev_ctrl_msg_wire);
 336         memset(&smsg, 0x00, sizeof(struct msghdr));
 337         smsg.msg_iov = &iov;
 338         smsg.msg_iovlen = 1;
 339         smsg.msg_control = cred_msg;
 340         smsg.msg_controllen = sizeof(cred_msg);
 341         size = recvmsg(conn->sock, &smsg, 0);
 342         if (size <  0) {
 343                 err(udev, "unable to receive user udevd message: %m\n");
 344                 goto err;
 345         }
 346         cmsg = CMSG_FIRSTHDR(&smsg);
 347         cred = (struct ucred *) CMSG_DATA(cmsg);
 348
 349         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 350                 err(udev, "no sender credentials received, message ignored\n");
 351                 goto err;
 352         }
 353
 354         if (cred->uid != 0) {
 355                 err(udev, "sender uid=%i, message ignored\n", cred->uid);
 356                 goto err;
 357         }
 358
 359         if (uctrl_msg->ctrl_msg_wire.magic != UDEV_CTRL_MAGIC) {
 360                 err(udev, "message magic 0x%08x doesn't match, ignore it\n", uctrl_msg->ctrl_msg_wire.magic);
 361                 goto err;
 362         }
 363
 364         dbg(udev, "created ctrl_msg %p (%i)\n", uctrl_msg, uctrl_msg->ctrl_msg_wire.type);
 365         return uctrl_msg;
 366 err:
 367         udev_ctrl_msg_unref(uctrl_msg);
 368         return NULL;
 369 }
 370
 371 struct udev_ctrl_msg *udev_ctrl_msg_ref(struct udev_ctrl_msg *ctrl_msg)
 372 {
 373         if (ctrl_msg == NULL)
 374                 return NULL;
 375         ctrl_msg->refcount++;
 376         return ctrl_msg;
 377 }
 378
 379 struct udev_ctrl_msg *udev_ctrl_msg_unref(struct udev_ctrl_msg *ctrl_msg)
 380 {
 381         if (ctrl_msg == NULL)
 382                 return NULL;
 383         ctrl_msg->refcount--;
 384         if (ctrl_msg->refcount > 0)
 385                 return ctrl_msg;
 386         dbg(ctrl_msg->conn->uctrl->udev, "release ctrl_msg %p\n", ctrl_msg);
 387         udev_ctrl_connection_unref(ctrl_msg->conn);
 388         free(ctrl_msg);
 389         return NULL;
 390 }
 391
 392 int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg)
 393 {
 394         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_LOG_LEVEL)
 395                 return ctrl_msg->ctrl_msg_wire.intval;
 396         return -1;
 397 }
 398
 399 int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 400 {
 401         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_STOP_EXEC_QUEUE)
 402                 return 1;
 403         return -1;
 404 }
 405
 406 int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 407 {
 408         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_START_EXEC_QUEUE)
 409                 return 1;
 410         return -1;
 411 }
 412
 413 int udev_ctrl_get_reload_rules(struct udev_ctrl_msg *ctrl_msg)
 414 {
 415         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_RELOAD_RULES)
 416                 return 1;
 417         return -1;
 418 }
 419
 420 const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg)
 421 {
 422         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_ENV)
 423                 return ctrl_msg->ctrl_msg_wire.buf;
 424         return NULL;
 425 }
 426
 427 int udev_ctrl_get_set_children_max(struct udev_ctrl_msg *ctrl_msg)
 428 {
 429         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_CHILDREN_MAX)
 430                 return ctrl_msg->ctrl_msg_wire.intval;
 431         return -1;
 432 }
 433
 434 int udev_ctrl_get_ping(struct udev_ctrl_msg *ctrl_msg)
 435 {
 436         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_PING)
 437                 return 1;
 438         return -1;
 439 }
 440
 441 int udev_ctrl_get_exit(struct udev_ctrl_msg *ctrl_msg)
 442 {
 443         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_EXIT)
 444                 return 1;
 445         return -1;
 446 }