udev/lib/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 program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <errno.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <stddef.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26 #include <sys/types.h>
  27 #include <sys/socket.h>
  28 #include <sys/un.h>
  29
  30 #include "libudev.h"
  31 #include "libudev-private.h"
  32
  33 /* last known version with this wire protocol */
  34 #define UDEV_CTRL_MAGIC                         "udevd-128"
  35
  36 enum udev_ctrl_msg_type {
  37         UDEV_CTRL_UNKNOWN,
  38         UDEV_CTRL_SET_LOG_LEVEL,
  39         UDEV_CTRL_STOP_EXEC_QUEUE,
  40         UDEV_CTRL_START_EXEC_QUEUE,
  41         UDEV_CTRL_RELOAD_RULES,
  42         UDEV_CTRL_SET_ENV,
  43         UDEV_CTRL_SET_MAX_CHILDS,
  44         UDEV_CTRL_SET_MAX_CHILDS_RUNNING,
  45 };
  46
  47 struct ctrl_msg_wire {
  48         char magic[32];
  49         enum udev_ctrl_msg_type type;
  50         union {
  51                 int intval;
  52                 char buf[256];
  53         };
  54 };
  55
  56 struct udev_ctrl_msg {
  57         int refcount;
  58         struct udev_ctrl *uctrl;
  59         struct ctrl_msg_wire ctrl_msg_wire;
  60 };
  61
  62 struct udev_ctrl {
  63         int refcount;
  64         struct udev *udev;
  65         int sock;
  66         struct sockaddr_un saddr;
  67         socklen_t addrlen;
  68 };
  69
  70 struct udev_ctrl *udev_ctrl_new_from_socket(struct udev *udev, const char *socket_path)
  71 {
  72         struct udev_ctrl *uctrl;
  73
  74         uctrl = malloc(sizeof(struct udev_ctrl));
  75         if (uctrl == NULL)
  76                 return NULL;
  77         memset(uctrl, 0x00, sizeof(struct udev_ctrl));
  78         uctrl->refcount = 1;
  79         uctrl->udev = udev;
  80
  81         uctrl->sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
  82         if (uctrl->sock < 0) {
  83                 err(udev, "error getting socket: %m\n");
  84                 udev_ctrl_unref(uctrl);
  85                 return NULL;
  86         }
  87
  88         uctrl->saddr.sun_family = AF_LOCAL;
  89         strcpy(uctrl->saddr.sun_path, socket_path);
  90         uctrl->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(uctrl->saddr.sun_path);
  91         /* translate leading '@' to abstract namespace */
  92         if (uctrl->saddr.sun_path[0] == '@')
  93                 uctrl->saddr.sun_path[0] = '\0';
  94
  95         return uctrl;
  96 }
  97
  98 int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl)
  99 {
 100         int err;
 101         const int feature_on = 1;
 102
 103         err= bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 104         if (err < 0) {
 105                 err(uctrl->udev, "bind failed: %m\n");
 106                 return err;
 107         }
 108
 109         /* enable receiving of the sender credentials */
 110         setsockopt(uctrl->sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 111         return 0;
 112 }
 113
 114 struct udev *udev_ctrl_get_udev(struct udev_ctrl *uctrl)
 115 {
 116         return uctrl->udev;
 117 }
 118
 119 struct udev_ctrl *udev_ctrl_ref(struct udev_ctrl *uctrl)
 120 {
 121         if (uctrl == NULL)
 122                 return NULL;
 123         uctrl->refcount++;
 124         return uctrl;
 125 }
 126
 127 void udev_ctrl_unref(struct udev_ctrl *uctrl)
 128 {
 129         if (uctrl == NULL)
 130                 return;
 131         uctrl->refcount--;
 132         if (uctrl->refcount > 0)
 133                 return;
 134         if (uctrl->sock >= 0)
 135                 close(uctrl->sock);
 136         free(uctrl);
 137 }
 138
 139 int udev_ctrl_get_fd(struct udev_ctrl *uctrl)
 140 {
 141         if (uctrl == NULL)
 142                 return -1;
 143         return uctrl->sock;
 144 }
 145
 146 static int ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf)
 147 {
 148         struct ctrl_msg_wire ctrl_msg_wire;
 149         int err;
 150
 151         memset(&ctrl_msg_wire, 0x00, sizeof(struct ctrl_msg_wire));
 152         strcpy(ctrl_msg_wire.magic, UDEV_CTRL_MAGIC);
 153         ctrl_msg_wire.type = type;
 154
 155         if (buf != NULL)
 156                 util_strlcpy(ctrl_msg_wire.buf, buf, sizeof(ctrl_msg_wire.buf));
 157         else
 158                 ctrl_msg_wire.intval = intval;
 159
 160         err = sendto(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 161         if (err == -1) {
 162                 err(uctrl->udev, "error sending message: %m\n");
 163         }
 164         return err;
 165 }
 166
 167 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority)
 168 {
 169         ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL);
 170         return 0;
 171 }
 172
 173 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl)
 174 {
 175         ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL);
 176         return 0;
 177 }
 178
 179 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl)
 180 {
 181         ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL);
 182         return 0;
 183 }
 184
 185 int udev_ctrl_send_reload_rules(struct udev_ctrl *uctrl)
 186 {
 187         ctrl_send(uctrl, UDEV_CTRL_RELOAD_RULES, 0, NULL);
 188         return 0;
 189 }
 190
 191 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key)
 192 {
 193         ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, key);
 194         return 0;
 195 }
 196
 197 int udev_ctrl_send_set_max_childs(struct udev_ctrl *uctrl, int count)
 198 {
 199         ctrl_send(uctrl, UDEV_CTRL_SET_MAX_CHILDS, count, NULL);
 200         return 0;
 201 }
 202
 203 struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl *uctrl)
 204 {
 205         struct udev_ctrl_msg *uctrl_msg;
 206         ssize_t size;
 207         struct msghdr smsg;
 208         struct cmsghdr *cmsg;
 209         struct iovec iov;
 210         struct ucred *cred;
 211         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 212
 213         uctrl_msg = malloc(sizeof(struct udev_ctrl_msg));
 214         if (uctrl_msg == NULL)
 215                 return NULL;
 216         memset(uctrl_msg, 0x00, sizeof(struct udev_ctrl_msg));
 217         uctrl_msg->refcount = 1;
 218         uctrl_msg->uctrl = uctrl;
 219
 220         iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 221         iov.iov_len = sizeof(struct udev_ctrl_msg);
 222
 223         memset(&smsg, 0x00, sizeof(struct msghdr));
 224         smsg.msg_iov = &iov;
 225         smsg.msg_iovlen = 1;
 226         smsg.msg_control = cred_msg;
 227         smsg.msg_controllen = sizeof(cred_msg);
 228
 229         size = recvmsg(uctrl->sock, &smsg, 0);
 230         if (size <  0) {
 231                 err(uctrl->udev, "unable to receive user udevd message: %m\n");
 232                 goto err;
 233         }
 234         cmsg = CMSG_FIRSTHDR(&smsg);
 235         cred = (struct ucred *) CMSG_DATA(cmsg);
 236
 237         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 238                 err(uctrl->udev, "no sender credentials received, message ignored\n");
 239                 goto err;
 240         }
 241
 242         if (cred->uid != 0) {
 243                 err(uctrl->udev, "sender uid=%i, message ignored\n", cred->uid);
 244                 goto err;
 245         }
 246
 247         if (strncmp(uctrl_msg->ctrl_msg_wire.magic, UDEV_CTRL_MAGIC, sizeof(UDEV_CTRL_MAGIC)) != 0 ) {
 248                 err(uctrl->udev, "message magic '%s' doesn't match, ignore it\n", uctrl_msg->ctrl_msg_wire.magic);
 249                 goto err;
 250         }
 251
 252         info(uctrl->udev, "created ctrl_msg %p (%i)\n", uctrl_msg, uctrl_msg->ctrl_msg_wire.type);
 253         return uctrl_msg;
 254 err:
 255         udev_ctrl_msg_unref(uctrl_msg);
 256         return NULL;
 257 }
 258
 259 struct udev_ctrl_msg *udev_ctrl_msg_ref(struct udev_ctrl_msg *ctrl_msg)
 260 {
 261         if (ctrl_msg == NULL)
 262                 return NULL;
 263         ctrl_msg->refcount++;
 264         return ctrl_msg;
 265 }
 266
 267 void udev_ctrl_msg_unref(struct udev_ctrl_msg *ctrl_msg)
 268 {
 269         if (ctrl_msg == NULL)
 270                 return;
 271         ctrl_msg->refcount--;
 272         if (ctrl_msg->refcount > 0)
 273                 return;
 274         info(ctrl_msg->uctrl->udev, "release ctrl_msg %p\n", ctrl_msg);
 275         free(ctrl_msg);
 276 }
 277
 278 int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg)
 279 {
 280         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_LOG_LEVEL)
 281                 return ctrl_msg->ctrl_msg_wire.intval;
 282         return -1;
 283 }
 284
 285 int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 286 {
 287         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_STOP_EXEC_QUEUE)
 288                 return 1;
 289         return -1;
 290 }
 291
 292 int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 293 {
 294         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_START_EXEC_QUEUE)
 295                 return 1;
 296         return -1;
 297 }
 298
 299 int udev_ctrl_get_reload_rules(struct udev_ctrl_msg *ctrl_msg)
 300 {
 301         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_RELOAD_RULES)
 302                 return 1;
 303         return -1;
 304 }
 305
 306 const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg)
 307 {
 308         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_ENV)
 309                 return ctrl_msg->ctrl_msg_wire.buf;
 310         return NULL;
 311 }
 312
 313 int udev_ctrl_get_set_max_childs(struct udev_ctrl_msg *ctrl_msg)
 314 {
 315         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_MAX_CHILDS)
 316                 return ctrl_msg->ctrl_msg_wire.intval;
 317         return -1;
 318 }