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 connected;
  64 };
  65
  66 struct udev_ctrl_connection {
  67         int refcount;
  68         struct udev_ctrl *uctrl;
  69         int sock;
  70 };
  71
  72 static struct udev_ctrl *udev_ctrl_new(struct udev *udev)
  73 {
  74         struct udev_ctrl *uctrl;
  75
  76         uctrl = calloc(1, sizeof(struct udev_ctrl));
  77         if (uctrl == NULL)
  78                 return NULL;
  79         uctrl->refcount = 1;
  80         uctrl->udev = udev;
  81         return uctrl;
  82 }
  83
  84 struct udev_ctrl *udev_ctrl_new_from_socket(struct udev *udev, const char *socket_path)
  85 {
  86         struct udev_ctrl *uctrl;
  87
  88         uctrl = udev_ctrl_new(udev);
  89         if (uctrl == NULL)
  90                 return NULL;
  91
  92         uctrl->sock = socket(AF_LOCAL, SOCK_SEQPACKET, 0);
  93         if (uctrl->sock < 0) {
  94                 err(udev, "error getting socket: %m\n");
  95                 udev_ctrl_unref(uctrl);
  96                 return NULL;
  97         }
  98
  99         uctrl->saddr.sun_family = AF_LOCAL;
 100         strcpy(uctrl->saddr.sun_path, socket_path);
 101         uctrl->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(uctrl->saddr.sun_path);
 102         /* translate leading '@' to abstract namespace */
 103         if (uctrl->saddr.sun_path[0] == '@')
 104                 uctrl->saddr.sun_path[0] = '\0';
 105         return uctrl;
 106 }
 107
 108 struct udev_ctrl *udev_ctrl_new_from_fd(struct udev *udev, int fd)
 109 {
 110         struct udev_ctrl *uctrl;
 111
 112         uctrl = udev_ctrl_new(udev);
 113         if (uctrl == NULL)
 114                 return NULL;
 115         uctrl->sock = fd;
 116
 117         return uctrl;
 118 }
 119
 120 int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl)
 121 {
 122         int err;
 123
 124         if (uctrl->addrlen > 0) {
 125                 err = bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 126                 if (err < 0) {
 127                         err = -errno;
 128                         err(uctrl->udev, "bind failed: %m\n");
 129                         return err;
 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         return 0;
 139 }
 140
 141 struct udev *udev_ctrl_get_udev(struct udev_ctrl *uctrl)
 142 {
 143         return uctrl->udev;
 144 }
 145
 146 struct udev_ctrl *udev_ctrl_ref(struct udev_ctrl *uctrl)
 147 {
 148         if (uctrl == NULL)
 149                 return NULL;
 150         uctrl->refcount++;
 151         return uctrl;
 152 }
 153
 154 struct udev_ctrl *udev_ctrl_unref(struct udev_ctrl *uctrl)
 155 {
 156         if (uctrl == NULL)
 157                 return NULL;
 158         uctrl->refcount--;
 159         if (uctrl->refcount > 0)
 160                 return uctrl;
 161         if (uctrl->sock >= 0)
 162                 close(uctrl->sock);
 163         free(uctrl);
 164         return NULL;
 165 }
 166
 167 int udev_ctrl_get_fd(struct udev_ctrl *uctrl)
 168 {
 169         if (uctrl == NULL)
 170                 return -1;
 171         return uctrl->sock;
 172 }
 173
 174 struct udev_ctrl_connection *udev_ctrl_get_connection(struct udev_ctrl *uctrl)
 175 {
 176         struct udev_ctrl_connection *conn;
 177         const int on = 1;
 178
 179         conn = calloc(1, sizeof(struct udev_ctrl_connection));
 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);
 186         if (conn->sock < 0) {
 187                 free(conn);
 188                 return NULL;
 189         }
 190
 191         /* enable receiving of the sender credentials */
 192         setsockopt(conn->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 193         udev_ctrl_ref(uctrl);
 194         return conn;
 195 }
 196
 197 struct udev_ctrl_connection *udev_ctrl_connection_ref(struct udev_ctrl_connection *conn)
 198 {
 199         if (conn == NULL)
 200                 return NULL;
 201         conn->refcount++;
 202         return conn;
 203 }
 204
 205 struct udev_ctrl_connection *udev_ctrl_connection_unref(struct udev_ctrl_connection *conn)
 206 {
 207         if (conn == NULL)
 208                 return NULL;
 209         conn->refcount--;
 210         if (conn->refcount > 0)
 211                 return conn;
 212         if (conn->sock >= 0)
 213                 close(conn->sock);
 214         udev_ctrl_unref(conn->uctrl);
 215         free(conn);
 216         return NULL;
 217 }
 218
 219 static int ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf, int timeout)
 220 {
 221         struct udev_ctrl_msg_wire ctrl_msg_wire;
 222         int err = 0;
 223
 224         memset(&ctrl_msg_wire, 0x00, sizeof(struct udev_ctrl_msg_wire));
 225         strcpy(ctrl_msg_wire.version, "udev-" VERSION);
 226         ctrl_msg_wire.magic = UDEV_CTRL_MAGIC;
 227         ctrl_msg_wire.type = type;
 228
 229         if (buf != NULL)
 230                 util_strscpy(ctrl_msg_wire.buf, sizeof(ctrl_msg_wire.buf), buf);
 231         else
 232                 ctrl_msg_wire.intval = intval;
 233
 234         if (!uctrl->connected) {
 235                 if (connect(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen) < 0) {
 236                         err = -errno;
 237                         goto out;
 238                 }
 239                 uctrl->connected = true;
 240         }
 241         if (send(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0) < 0) {
 242                 err = -errno;
 243                 goto out;
 244         }
 245
 246         /* wait for peer message handling or disconnect */
 247         for (;;) {
 248                 struct pollfd pfd[1];
 249                 int r;
 250
 251                 pfd[0].fd = uctrl->sock;
 252                 pfd[0].events = POLLIN;
 253                 r = poll(pfd, 1, timeout * 1000);
 254                 if (r  < 0) {
 255                         if (errno == EINTR)
 256                                 continue;
 257                         err = -errno;
 258                         break;
 259                 }
 260
 261                 if (r > 0 && pfd[0].revents & POLLERR) {
 262                         err = -EIO;
 263                         break;
 264                 }
 265
 266                 if (r == 0)
 267                         err = -ETIMEDOUT;
 268                 break;
 269         }
 270 out:
 271         return err;
 272 }
 273
 274 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority, int timeout)
 275 {
 276         return ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL, timeout);
 277 }
 278
 279 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl, int timeout)
 280 {
 281         return ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL, timeout);
 282 }
 283
 284 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl, int timeout)
 285 {
 286         return ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL, timeout);
 287 }
 288
 289 int udev_ctrl_send_reload_rules(struct udev_ctrl *uctrl, int timeout)
 290 {
 291         return ctrl_send(uctrl, UDEV_CTRL_RELOAD_RULES, 0, NULL, timeout);
 292 }
 293
 294 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key, int timeout)
 295 {
 296         return ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, key, timeout);
 297 }
 298
 299 int udev_ctrl_send_set_children_max(struct udev_ctrl *uctrl, int count, int timeout)
 300 {
 301         return ctrl_send(uctrl, UDEV_CTRL_SET_CHILDREN_MAX, count, NULL, timeout);
 302 }
 303
 304 int udev_ctrl_send_ping(struct udev_ctrl *uctrl, int timeout)
 305 {
 306         return ctrl_send(uctrl, UDEV_CTRL_PING, 0, NULL, timeout);
 307 }
 308
 309 int udev_ctrl_send_exit(struct udev_ctrl *uctrl, int timeout)
 310 {
 311         return ctrl_send(uctrl, UDEV_CTRL_EXIT, 0, NULL, timeout);
 312 }
 313
 314 struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl_connection *conn)
 315 {
 316         struct udev *udev = conn->uctrl->udev;
 317         struct udev_ctrl_msg *uctrl_msg;
 318         ssize_t size;
 319         struct msghdr smsg;
 320         struct cmsghdr *cmsg;
 321         struct iovec iov;
 322         struct ucred *cred;
 323         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 324
 325         uctrl_msg = calloc(1, sizeof(struct udev_ctrl_msg));
 326         if (uctrl_msg == NULL)
 327                 return NULL;
 328         uctrl_msg->refcount = 1;
 329         uctrl_msg->conn = conn;
 330
 331         iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 332         iov.iov_len = sizeof(struct udev_ctrl_msg_wire);
 333
 334         memset(&smsg, 0x00, sizeof(struct msghdr));
 335         smsg.msg_iov = &iov;
 336         smsg.msg_iovlen = 1;
 337         smsg.msg_control = cred_msg;
 338         smsg.msg_controllen = sizeof(cred_msg);
 339
 340         size = recvmsg(conn->sock, &smsg, 0);
 341         if (size <  0) {
 342                 err(udev, "unable to receive user udevd message: %m\n");
 343                 goto err;
 344         }
 345         cmsg = CMSG_FIRSTHDR(&smsg);
 346         cred = (struct ucred *) CMSG_DATA(cmsg);
 347
 348         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 349                 err(udev, "no sender credentials received, message ignored\n");
 350                 goto err;
 351         }
 352
 353         if (cred->uid != 0) {
 354                 err(udev, "sender uid=%i, message ignored\n", cred->uid);
 355                 goto err;
 356         }
 357
 358         if (uctrl_msg->ctrl_msg_wire.magic != UDEV_CTRL_MAGIC) {
 359                 err(udev, "message magic 0x%08x doesn't match, ignore it\n", uctrl_msg->ctrl_msg_wire.magic);
 360                 goto err;
 361         }
 362
 363         dbg(udev, "created ctrl_msg %p (%i)\n", uctrl_msg, uctrl_msg->ctrl_msg_wire.type);
 364         udev_ctrl_connection_ref(conn);
 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 }