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|SOCK_NONBLOCK);
 188         if (conn->sock < 0) {
 189                 if (errno != EINTR)
 190                         err(uctrl->udev, "unable to receive ctrl connection: %m\n");
 191                 free(conn);
 192                 return NULL;
 193         }
 194
 195         /* enable receiving of the sender credentials */
 196         setsockopt(conn->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 197         udev_ctrl_ref(uctrl);
 198         return conn;
 199 }
 200
 201 struct udev_ctrl_connection *udev_ctrl_connection_ref(struct udev_ctrl_connection *conn)
 202 {
 203         if (conn == NULL)
 204                 return NULL;
 205         conn->refcount++;
 206         return conn;
 207 }
 208
 209 struct udev_ctrl_connection *udev_ctrl_connection_unref(struct udev_ctrl_connection *conn)
 210 {
 211         if (conn == NULL)
 212                 return NULL;
 213         conn->refcount--;
 214         if (conn->refcount > 0)
 215                 return conn;
 216         if (conn->sock >= 0)
 217                 close(conn->sock);
 218         udev_ctrl_unref(conn->uctrl);
 219         free(conn);
 220         return NULL;
 221 }
 222
 223 static int ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf, int timeout)
 224 {
 225         struct udev_ctrl_msg_wire ctrl_msg_wire;
 226         int err = 0;
 227
 228         memset(&ctrl_msg_wire, 0x00, sizeof(struct udev_ctrl_msg_wire));
 229         strcpy(ctrl_msg_wire.version, "udev-" VERSION);
 230         ctrl_msg_wire.magic = UDEV_CTRL_MAGIC;
 231         ctrl_msg_wire.type = type;
 232
 233         if (buf != NULL)
 234                 util_strscpy(ctrl_msg_wire.buf, sizeof(ctrl_msg_wire.buf), buf);
 235         else
 236                 ctrl_msg_wire.intval = intval;
 237
 238         if (!uctrl->connected) {
 239                 if (connect(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen) < 0) {
 240                         err = -errno;
 241                         goto out;
 242                 }
 243                 uctrl->connected = true;
 244         }
 245         if (send(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0) < 0) {
 246                 err = -errno;
 247                 goto out;
 248         }
 249
 250         /* wait for peer message handling or disconnect */
 251         for (;;) {
 252                 struct pollfd pfd[1];
 253                 int r;
 254
 255                 pfd[0].fd = uctrl->sock;
 256                 pfd[0].events = POLLIN;
 257                 r = poll(pfd, 1, timeout * 1000);
 258                 if (r  < 0) {
 259                         if (errno == EINTR)
 260                                 continue;
 261                         err = -errno;
 262                         break;
 263                 }
 264
 265                 if (r > 0 && pfd[0].revents & POLLERR) {
 266                         err = -EIO;
 267                         break;
 268                 }
 269
 270                 if (r == 0)
 271                         err = -ETIMEDOUT;
 272                 break;
 273         }
 274 out:
 275         return err;
 276 }
 277
 278 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority, int timeout)
 279 {
 280         return ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL, timeout);
 281 }
 282
 283 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl, int timeout)
 284 {
 285         return ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL, timeout);
 286 }
 287
 288 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl, int timeout)
 289 {
 290         return ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL, timeout);
 291 }
 292
 293 int udev_ctrl_send_reload_rules(struct udev_ctrl *uctrl, int timeout)
 294 {
 295         return ctrl_send(uctrl, UDEV_CTRL_RELOAD_RULES, 0, NULL, timeout);
 296 }
 297
 298 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key, int timeout)
 299 {
 300         return ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, key, timeout);
 301 }
 302
 303 int udev_ctrl_send_set_children_max(struct udev_ctrl *uctrl, int count, int timeout)
 304 {
 305         return ctrl_send(uctrl, UDEV_CTRL_SET_CHILDREN_MAX, count, NULL, timeout);
 306 }
 307
 308 int udev_ctrl_send_ping(struct udev_ctrl *uctrl, int timeout)
 309 {
 310         return ctrl_send(uctrl, UDEV_CTRL_PING, 0, NULL, timeout);
 311 }
 312
 313 int udev_ctrl_send_exit(struct udev_ctrl *uctrl, int timeout)
 314 {
 315         return ctrl_send(uctrl, UDEV_CTRL_EXIT, 0, NULL, timeout);
 316 }
 317
 318 struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl_connection *conn)
 319 {
 320         struct udev *udev = conn->uctrl->udev;
 321         struct udev_ctrl_msg *uctrl_msg;
 322         ssize_t size;
 323         struct msghdr smsg;
 324         struct cmsghdr *cmsg;
 325         struct iovec iov;
 326         struct ucred *cred;
 327         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 328
 329         uctrl_msg = calloc(1, sizeof(struct udev_ctrl_msg));
 330         if (uctrl_msg == NULL)
 331                 return NULL;
 332         uctrl_msg->refcount = 1;
 333         uctrl_msg->conn = conn;
 334         udev_ctrl_connection_ref(conn);
 335
 336         iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 337         iov.iov_len = sizeof(struct udev_ctrl_msg_wire);
 338         memset(&smsg, 0x00, sizeof(struct msghdr));
 339         smsg.msg_iov = &iov;
 340         smsg.msg_iovlen = 1;
 341         smsg.msg_control = cred_msg;
 342         smsg.msg_controllen = sizeof(cred_msg);
 343         size = recvmsg(conn->sock, &smsg, 0);
 344         if (size <  0) {
 345                 err(udev, "unable to receive user udevd message: %m\n");
 346                 goto err;
 347         }
 348         cmsg = CMSG_FIRSTHDR(&smsg);
 349         cred = (struct ucred *) CMSG_DATA(cmsg);
 350
 351         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 352                 err(udev, "no sender credentials received, message ignored\n");
 353                 goto err;
 354         }
 355
 356         if (cred->uid != 0) {
 357                 err(udev, "sender uid=%i, message ignored\n", cred->uid);
 358                 goto err;
 359         }
 360
 361         if (uctrl_msg->ctrl_msg_wire.magic != UDEV_CTRL_MAGIC) {
 362                 err(udev, "message magic 0x%08x doesn't match, ignore it\n", uctrl_msg->ctrl_msg_wire.magic);
 363                 goto err;
 364         }
 365
 366         dbg(udev, "created ctrl_msg %p (%i)\n", uctrl_msg, uctrl_msg->ctrl_msg_wire.type);
 367         return uctrl_msg;
 368 err:
 369         udev_ctrl_msg_unref(uctrl_msg);
 370         return NULL;
 371 }
 372
 373 struct udev_ctrl_msg *udev_ctrl_msg_ref(struct udev_ctrl_msg *ctrl_msg)
 374 {
 375         if (ctrl_msg == NULL)
 376                 return NULL;
 377         ctrl_msg->refcount++;
 378         return ctrl_msg;
 379 }
 380
 381 struct udev_ctrl_msg *udev_ctrl_msg_unref(struct udev_ctrl_msg *ctrl_msg)
 382 {
 383         if (ctrl_msg == NULL)
 384                 return NULL;
 385         ctrl_msg->refcount--;
 386         if (ctrl_msg->refcount > 0)
 387                 return ctrl_msg;
 388         dbg(ctrl_msg->conn->uctrl->udev, "release ctrl_msg %p\n", ctrl_msg);
 389         udev_ctrl_connection_unref(ctrl_msg->conn);
 390         free(ctrl_msg);
 391         return NULL;
 392 }
 393
 394 int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg)
 395 {
 396         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_LOG_LEVEL)
 397                 return ctrl_msg->ctrl_msg_wire.intval;
 398         return -1;
 399 }
 400
 401 int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 402 {
 403         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_STOP_EXEC_QUEUE)
 404                 return 1;
 405         return -1;
 406 }
 407
 408 int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 409 {
 410         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_START_EXEC_QUEUE)
 411                 return 1;
 412         return -1;
 413 }
 414
 415 int udev_ctrl_get_reload_rules(struct udev_ctrl_msg *ctrl_msg)
 416 {
 417         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_RELOAD_RULES)
 418                 return 1;
 419         return -1;
 420 }
 421
 422 const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg)
 423 {
 424         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_ENV)
 425                 return ctrl_msg->ctrl_msg_wire.buf;
 426         return NULL;
 427 }
 428
 429 int udev_ctrl_get_set_children_max(struct udev_ctrl_msg *ctrl_msg)
 430 {
 431         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_CHILDREN_MAX)
 432                 return ctrl_msg->ctrl_msg_wire.intval;
 433         return -1;
 434 }
 435
 436 int udev_ctrl_get_ping(struct udev_ctrl_msg *ctrl_msg)
 437 {
 438         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_PING)
 439                 return 1;
 440         return -1;
 441 }
 442
 443 int udev_ctrl_get_exit(struct udev_ctrl_msg *ctrl_msg)
 444 {
 445         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_EXIT)
 446                 return 1;
 447         return -1;
 448 }