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 "config.h"
  21
  22 #include <errno.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <stddef.h>
  26 #include <string.h>
  27 #include <unistd.h>
  28 #include <sys/types.h>
  29 #include <sys/socket.h>
  30 #include <sys/un.h>
  31
  32 #include "../udev.h"
  33 #include "libudev.h"
  34 #include "libudev-private.h"
  35
  36 #define UDEV_CTRL_MAGIC                         "udevd-128"
  37
  38 enum udev_ctrl_msg_type {
  39         UDEV_CTRL_UNKNOWN,
  40         UDEV_CTRL_SET_LOG_LEVEL,
  41         UDEV_CTRL_STOP_EXEC_QUEUE,
  42         UDEV_CTRL_START_EXEC_QUEUE,
  43         UDEV_CTRL_RELOAD_RULES,
  44         UDEV_CTRL_SET_ENV,
  45         UDEV_CTRL_SET_MAX_CHILDS,
  46         UDEV_CTRL_SET_MAX_CHILDS_RUNNING,
  47 };
  48
  49 struct ctrl_msg {
  50         char magic[32];
  51         enum udev_ctrl_msg_type type;
  52         union {
  53                 int intval;
  54                 char buf[256];
  55         };
  56 };
  57
  58 struct udev_ctrl_msg {
  59         int refcount;
  60         struct udev_ctrl *uctrl;
  61         struct ctrl_msg ctrl_msg;
  62 };
  63
  64 struct udev_ctrl {
  65         int refcount;
  66         struct udev *udev;
  67         int sock;
  68         struct sockaddr_un saddr;
  69         socklen_t addrlen;
  70 };
  71
  72 struct udev_ctrl *udev_ctrl_new_from_socket(struct udev *udev, const char *socket_path)
  73 {
  74         struct udev_ctrl *uctrl;
  75
  76         uctrl = malloc(sizeof(struct udev_ctrl));
  77         if (uctrl == NULL)
  78                 return NULL;
  79         memset(uctrl, 0x00, sizeof(struct udev_ctrl));
  80         uctrl->refcount = 1;
  81         uctrl->udev = udev;
  82
  83         uctrl->sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
  84         if (uctrl->sock < 0) {
  85                 err(udev, "error getting socket: %s\n", strerror(errno));
  86                 udev_ctrl_unref(uctrl);
  87                 return NULL;
  88         }
  89
  90         uctrl->saddr.sun_family = AF_LOCAL;
  91         strcpy(uctrl->saddr.sun_path, socket_path);
  92         uctrl->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(uctrl->saddr.sun_path);
  93         /* translate leading '@' to abstract namespace */
  94         if (uctrl->saddr.sun_path[0] == '@')
  95                 uctrl->saddr.sun_path[0] = '\0';
  96
  97         return uctrl;
  98 }
  99
 100 int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl)
 101 {
 102         int err;
 103         const int feature_on = 1;
 104
 105         err= bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 106         if (err < 0) {
 107                 err(uctrl->udev, "bind failed: %s\n", strerror(errno));
 108                 return err;
 109         }
 110
 111         /* enable receiving of the sender credentials */
 112         setsockopt(uctrl->sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 113         return 0;
 114 }
 115
 116 struct udev *udev_ctrl_get_udev(struct udev_ctrl *uctrl)
 117 {
 118         return uctrl->udev;
 119 }
 120
 121 struct udev_ctrl *udev_ctrl_ref(struct udev_ctrl *uctrl)
 122 {
 123         if (uctrl == NULL)
 124                 return NULL;
 125         uctrl->refcount++;
 126         return uctrl;
 127 }
 128
 129 void udev_ctrl_unref(struct udev_ctrl *uctrl)
 130 {
 131         if (uctrl == NULL)
 132                 return;
 133         uctrl->refcount--;
 134         if (uctrl->refcount > 0)
 135                 return;
 136         if (uctrl->sock >= 0)
 137                 close(uctrl->sock);
 138         free(uctrl);
 139 }
 140
 141 int udev_ctrl_get_fd(struct udev_ctrl *uctrl)
 142 {
 143         if (uctrl == NULL)
 144                 return -1;
 145         return uctrl->sock;
 146 }
 147
 148 static int ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf)
 149 {
 150         struct ctrl_msg ctrl_msg;
 151         int err;
 152
 153         memset(&ctrl_msg, 0x00, sizeof(struct ctrl_msg));
 154         strcpy(ctrl_msg.magic, UDEV_CTRL_MAGIC);
 155         ctrl_msg.type = type;
 156
 157         if (buf != NULL)
 158                 strlcpy(ctrl_msg.buf, buf, sizeof(ctrl_msg.buf));
 159         else
 160                 ctrl_msg.intval = intval;
 161
 162         err = sendto(uctrl->sock, &ctrl_msg, sizeof(ctrl_msg), 0, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 163         if (err == -1) {
 164                 err(uctrl->udev, "error sending message: %s\n", strerror(errno));
 165         }
 166         return err;
 167 }
 168
 169 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority)
 170 {
 171         ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL);
 172         return 0;
 173 }
 174
 175 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl)
 176 {
 177         ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL);
 178         return 0;
 179 }
 180
 181 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl)
 182 {
 183         ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL);
 184         return 0;
 185 }
 186
 187 int udev_ctrl_send_reload_rules(struct udev_ctrl *uctrl)
 188 {
 189         ctrl_send(uctrl, UDEV_CTRL_RELOAD_RULES, 0, NULL);
 190         return 0;
 191 }
 192
 193 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key)
 194 {
 195         ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, optarg);
 196         return 0;
 197 }
 198
 199 int udev_ctrl_send_set_max_childs(struct udev_ctrl *uctrl, int count)
 200 {
 201         ctrl_send(uctrl, UDEV_CTRL_SET_MAX_CHILDS, count, NULL);
 202         return 0;
 203 }
 204
 205 struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl *uctrl)
 206 {
 207         struct udev_ctrl_msg *uctrl_msg;
 208         ssize_t size;
 209         struct msghdr smsg;
 210         struct cmsghdr *cmsg;
 211         struct iovec iov;
 212         struct ucred *cred;
 213         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 214
 215         uctrl_msg = malloc(sizeof(struct udev_ctrl_msg));
 216         if (uctrl_msg == NULL)
 217                 return NULL;
 218         memset(uctrl_msg, 0x00, sizeof(struct udev_ctrl_msg));
 219         uctrl_msg->refcount = 1;
 220         uctrl_msg->uctrl = uctrl;
 221
 222         iov.iov_base = &uctrl_msg->ctrl_msg;
 223         iov.iov_len = sizeof(struct udev_ctrl_msg);
 224
 225         memset(&smsg, 0x00, sizeof(struct msghdr));
 226         smsg.msg_iov = &iov;
 227         smsg.msg_iovlen = 1;
 228         smsg.msg_control = cred_msg;
 229         smsg.msg_controllen = sizeof(cred_msg);
 230
 231         size = recvmsg(uctrl->sock, &smsg, 0);
 232         if (size <  0) {
 233                 err(uctrl->udev, "unable to receive user udevd message: %s\n", strerror(errno));
 234                 goto err;
 235         }
 236         cmsg = CMSG_FIRSTHDR(&smsg);
 237         cred = (struct ucred *) CMSG_DATA(cmsg);
 238
 239         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 240                 err(uctrl->udev, "no sender credentials received, message ignored\n");
 241                 goto err;
 242         }
 243
 244         if (cred->uid != 0) {
 245                 err(uctrl->udev, "sender uid=%i, message ignored\n", cred->uid);
 246                 goto err;
 247         }
 248
 249         if (strncmp(uctrl_msg->ctrl_msg.magic, UDEV_CTRL_MAGIC, sizeof(UDEV_CTRL_MAGIC)) != 0 ) {
 250                 err(uctrl->udev, "message magic '%s' doesn't match, ignore it\n", uctrl_msg->ctrl_msg.magic);
 251                 goto err;
 252         }
 253
 254         info(uctrl->udev, "created ctrl_msg %p (%i)\n", uctrl_msg, uctrl_msg->ctrl_msg.type);
 255         return uctrl_msg;
 256 err:
 257         udev_ctrl_msg_unref(uctrl_msg);
 258         return NULL;
 259 }
 260
 261 struct udev_ctrl_msg *udev_ctrl_msg_ref(struct udev_ctrl_msg *ctrl_msg)
 262 {
 263         if (ctrl_msg == NULL)
 264                 return NULL;
 265         ctrl_msg->refcount++;
 266         return ctrl_msg;
 267 }
 268
 269 void udev_ctrl_msg_unref(struct udev_ctrl_msg *ctrl_msg)
 270 {
 271         if (ctrl_msg == NULL)
 272                 return;
 273         ctrl_msg->refcount--;
 274         if (ctrl_msg->refcount > 0)
 275                 return;
 276         info(ctrl_msg->uctrl->udev, "release ctrl_msg %p\n", ctrl_msg);
 277         free(ctrl_msg);
 278 }
 279
 280 int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg)
 281 {
 282         if (ctrl_msg->ctrl_msg.type == UDEV_CTRL_SET_LOG_LEVEL)
 283                 return ctrl_msg->ctrl_msg.intval;
 284         return -1;
 285 }
 286
 287 int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 288 {
 289         if (ctrl_msg->ctrl_msg.type == UDEV_CTRL_STOP_EXEC_QUEUE)
 290                 return 1;
 291         return -1;
 292 }
 293
 294 int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 295 {
 296         if (ctrl_msg->ctrl_msg.type == UDEV_CTRL_START_EXEC_QUEUE)
 297                 return 1;
 298         return -1;
 299 }
 300
 301 int udev_ctrl_get_reload_rules(struct udev_ctrl_msg *ctrl_msg)
 302 {
 303         if (ctrl_msg->ctrl_msg.type == UDEV_CTRL_RELOAD_RULES)
 304                 return 1;
 305         return -1;
 306 }
 307
 308 const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg)
 309 {
 310         if (ctrl_msg->ctrl_msg.type == UDEV_CTRL_SET_ENV)
 311                 return ctrl_msg->ctrl_msg.buf;
 312         return NULL;
 313 }
 314
 315 int udev_ctrl_get_set_max_childs(struct udev_ctrl_msg *ctrl_msg)
 316 {
 317         if (ctrl_msg->ctrl_msg.type == UDEV_CTRL_SET_MAX_CHILDS)
 318                 return ctrl_msg->ctrl_msg.intval;
 319         return -1;
 320 }