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 #define UDEV_CTRL_MAGIC                         "udevd-128"
  34
  35 enum udev_ctrl_msg_type {
  36         UDEV_CTRL_UNKNOWN,
  37         UDEV_CTRL_SET_LOG_LEVEL,
  38         UDEV_CTRL_STOP_EXEC_QUEUE,
  39         UDEV_CTRL_START_EXEC_QUEUE,
  40         UDEV_CTRL_RELOAD_RULES,
  41         UDEV_CTRL_SET_ENV,
  42         UDEV_CTRL_SET_MAX_CHILDS,
  43         UDEV_CTRL_SET_MAX_CHILDS_RUNNING,
  44 };
  45
  46 struct ctrl_msg_wire {
  47         char magic[32];
  48         enum udev_ctrl_msg_type type;
  49         union {
  50                 int intval;
  51                 char buf[256];
  52         };
  53 };
  54
  55 struct udev_ctrl_msg {
  56         int refcount;
  57         struct udev_ctrl *uctrl;
  58         struct ctrl_msg_wire ctrl_msg_wire;
  59 };
  60
  61 struct udev_ctrl {
  62         int refcount;
  63         struct udev *udev;
  64         int sock;
  65         struct sockaddr_un saddr;
  66         socklen_t addrlen;
  67 };
  68
  69 struct udev_ctrl *udev_ctrl_new_from_socket(struct udev *udev, const char *socket_path)
  70 {
  71         struct udev_ctrl *uctrl;
  72
  73         uctrl = malloc(sizeof(struct udev_ctrl));
  74         if (uctrl == NULL)
  75                 return NULL;
  76         memset(uctrl, 0x00, sizeof(struct udev_ctrl));
  77         uctrl->refcount = 1;
  78         uctrl->udev = udev;
  79
  80         uctrl->sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
  81         if (uctrl->sock < 0) {
  82                 err(udev, "error getting socket: %s\n", strerror(errno));
  83                 udev_ctrl_unref(uctrl);
  84                 return NULL;
  85         }
  86
  87         uctrl->saddr.sun_family = AF_LOCAL;
  88         strcpy(uctrl->saddr.sun_path, socket_path);
  89         uctrl->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(uctrl->saddr.sun_path);
  90         /* translate leading '@' to abstract namespace */
  91         if (uctrl->saddr.sun_path[0] == '@')
  92                 uctrl->saddr.sun_path[0] = '\0';
  93
  94         return uctrl;
  95 }
  96
  97 int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl)
  98 {
  99         int err;
 100         const int feature_on = 1;
 101
 102         err= bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 103         if (err < 0) {
 104                 err(uctrl->udev, "bind failed: %s\n", strerror(errno));
 105                 return err;
 106         }
 107
 108         /* enable receiving of the sender credentials */
 109         setsockopt(uctrl->sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 110         return 0;
 111 }
 112
 113 struct udev *udev_ctrl_get_udev(struct udev_ctrl *uctrl)
 114 {
 115         return uctrl->udev;
 116 }
 117
 118 struct udev_ctrl *udev_ctrl_ref(struct udev_ctrl *uctrl)
 119 {
 120         if (uctrl == NULL)
 121                 return NULL;
 122         uctrl->refcount++;
 123         return uctrl;
 124 }
 125
 126 void udev_ctrl_unref(struct udev_ctrl *uctrl)
 127 {
 128         if (uctrl == NULL)
 129                 return;
 130         uctrl->refcount--;
 131         if (uctrl->refcount > 0)
 132                 return;
 133         if (uctrl->sock >= 0)
 134                 close(uctrl->sock);
 135         free(uctrl);
 136 }
 137
 138 int udev_ctrl_get_fd(struct udev_ctrl *uctrl)
 139 {
 140         if (uctrl == NULL)
 141                 return -1;
 142         return uctrl->sock;
 143 }
 144
 145 static int ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf)
 146 {
 147         struct ctrl_msg_wire ctrl_msg_wire;
 148         int err;
 149
 150         memset(&ctrl_msg_wire, 0x00, sizeof(struct ctrl_msg_wire));
 151         strcpy(ctrl_msg_wire.magic, UDEV_CTRL_MAGIC);
 152         ctrl_msg_wire.type = type;
 153
 154         if (buf != NULL)
 155                 util_strlcpy(ctrl_msg_wire.buf, buf, sizeof(ctrl_msg_wire.buf));
 156         else
 157                 ctrl_msg_wire.intval = intval;
 158
 159         err = sendto(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 160         if (err == -1) {
 161                 err(uctrl->udev, "error sending message: %s\n", strerror(errno));
 162         }
 163         return err;
 164 }
 165
 166 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority)
 167 {
 168         ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL);
 169         return 0;
 170 }
 171
 172 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl)
 173 {
 174         ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL);
 175         return 0;
 176 }
 177
 178 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl)
 179 {
 180         ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL);
 181         return 0;
 182 }
 183
 184 int udev_ctrl_send_reload_rules(struct udev_ctrl *uctrl)
 185 {
 186         ctrl_send(uctrl, UDEV_CTRL_RELOAD_RULES, 0, NULL);
 187         return 0;
 188 }
 189
 190 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key)
 191 {
 192         ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, optarg);
 193         return 0;
 194 }
 195
 196 int udev_ctrl_send_set_max_childs(struct udev_ctrl *uctrl, int count)
 197 {
 198         ctrl_send(uctrl, UDEV_CTRL_SET_MAX_CHILDS, count, NULL);
 199         return 0;
 200 }
 201
 202 struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl *uctrl)
 203 {
 204         struct udev_ctrl_msg *uctrl_msg;
 205         ssize_t size;
 206         struct msghdr smsg;
 207         struct cmsghdr *cmsg;
 208         struct iovec iov;
 209         struct ucred *cred;
 210         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 211
 212         uctrl_msg = malloc(sizeof(struct udev_ctrl_msg));
 213         if (uctrl_msg == NULL)
 214                 return NULL;
 215         memset(uctrl_msg, 0x00, sizeof(struct udev_ctrl_msg));
 216         uctrl_msg->refcount = 1;
 217         uctrl_msg->uctrl = uctrl;
 218
 219         iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 220         iov.iov_len = sizeof(struct udev_ctrl_msg);
 221
 222         memset(&smsg, 0x00, sizeof(struct msghdr));
 223         smsg.msg_iov = &iov;
 224         smsg.msg_iovlen = 1;
 225         smsg.msg_control = cred_msg;
 226         smsg.msg_controllen = sizeof(cred_msg);
 227
 228         size = recvmsg(uctrl->sock, &smsg, 0);
 229         if (size <  0) {
 230                 err(uctrl->udev, "unable to receive user udevd message: %s\n", strerror(errno));
 231                 goto err;
 232         }
 233         cmsg = CMSG_FIRSTHDR(&smsg);
 234         cred = (struct ucred *) CMSG_DATA(cmsg);
 235
 236         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 237                 err(uctrl->udev, "no sender credentials received, message ignored\n");
 238                 goto err;
 239         }
 240
 241         if (cred->uid != 0) {
 242                 err(uctrl->udev, "sender uid=%i, message ignored\n", cred->uid);
 243                 goto err;
 244         }
 245
 246         if (strncmp(uctrl_msg->ctrl_msg_wire.magic, UDEV_CTRL_MAGIC, sizeof(UDEV_CTRL_MAGIC)) != 0 ) {
 247                 err(uctrl->udev, "message magic '%s' doesn't match, ignore it\n", uctrl_msg->ctrl_msg_wire.magic);
 248                 goto err;
 249         }
 250
 251         info(uctrl->udev, "created ctrl_msg %p (%i)\n", uctrl_msg, uctrl_msg->ctrl_msg_wire.type);
 252         return uctrl_msg;
 253 err:
 254         udev_ctrl_msg_unref(uctrl_msg);
 255         return NULL;
 256 }
 257
 258 struct udev_ctrl_msg *udev_ctrl_msg_ref(struct udev_ctrl_msg *ctrl_msg)
 259 {
 260         if (ctrl_msg == NULL)
 261                 return NULL;
 262         ctrl_msg->refcount++;
 263         return ctrl_msg;
 264 }
 265
 266 void udev_ctrl_msg_unref(struct udev_ctrl_msg *ctrl_msg)
 267 {
 268         if (ctrl_msg == NULL)
 269                 return;
 270         ctrl_msg->refcount--;
 271         if (ctrl_msg->refcount > 0)
 272                 return;
 273         info(ctrl_msg->uctrl->udev, "release ctrl_msg %p\n", ctrl_msg);
 274         free(ctrl_msg);
 275 }
 276
 277 int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg)
 278 {
 279         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_LOG_LEVEL)
 280                 return ctrl_msg->ctrl_msg_wire.intval;
 281         return -1;
 282 }
 283
 284 int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 285 {
 286         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_STOP_EXEC_QUEUE)
 287                 return 1;
 288         return -1;
 289 }
 290
 291 int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 292 {
 293         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_START_EXEC_QUEUE)
 294                 return 1;
 295         return -1;
 296 }
 297
 298 int udev_ctrl_get_reload_rules(struct udev_ctrl_msg *ctrl_msg)
 299 {
 300         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_RELOAD_RULES)
 301                 return 1;
 302         return -1;
 303 }
 304
 305 const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg)
 306 {
 307         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_ENV)
 308                 return ctrl_msg->ctrl_msg_wire.buf;
 309         return NULL;
 310 }
 311
 312 int udev_ctrl_get_set_max_childs(struct udev_ctrl_msg *ctrl_msg)
 313 {
 314         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_MAX_CHILDS)
 315                 return ctrl_msg->ctrl_msg_wire.intval;
 316         return -1;
 317 }