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                         0xdead1dea
  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 udev_ctrl_msg_wire {
  48         char version[16];
  49         unsigned int magic;
  50         enum udev_ctrl_msg_type type;
  51         union {
  52                 int intval;
  53                 char buf[256];
  54         };
  55 };
  56
  57 struct udev_ctrl_msg {
  58         int refcount;
  59         struct udev_ctrl *uctrl;
  60         struct udev_ctrl_msg_wire ctrl_msg_wire;
  61 };
  62
  63 struct udev_ctrl {
  64         int refcount;
  65         struct udev *udev;
  66         int sock;
  67         struct sockaddr_un saddr;
  68         socklen_t addrlen;
  69 };
  70
  71 struct udev_ctrl *udev_ctrl_new_from_socket(struct udev *udev, const char *socket_path)
  72 {
  73         struct udev_ctrl *uctrl;
  74
  75         uctrl = malloc(sizeof(struct udev_ctrl));
  76         if (uctrl == NULL)
  77                 return NULL;
  78         memset(uctrl, 0x00, sizeof(struct udev_ctrl));
  79         uctrl->refcount = 1;
  80         uctrl->udev = udev;
  81
  82         uctrl->sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
  83         if (uctrl->sock < 0) {
  84                 err(udev, "error getting socket: %m\n");
  85                 udev_ctrl_unref(uctrl);
  86                 return NULL;
  87         }
  88
  89         uctrl->saddr.sun_family = AF_LOCAL;
  90         strcpy(uctrl->saddr.sun_path, socket_path);
  91         uctrl->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(uctrl->saddr.sun_path);
  92         /* translate leading '@' to abstract namespace */
  93         if (uctrl->saddr.sun_path[0] == '@')
  94                 uctrl->saddr.sun_path[0] = '\0';
  95
  96         return uctrl;
  97 }
  98
  99 int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl)
 100 {
 101         int err;
 102         const int feature_on = 1;
 103
 104         err= bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 105         if (err < 0) {
 106                 err(uctrl->udev, "bind failed: %m\n");
 107                 return err;
 108         }
 109
 110         /* enable receiving of the sender credentials */
 111         setsockopt(uctrl->sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 112         return 0;
 113 }
 114
 115 struct udev *udev_ctrl_get_udev(struct udev_ctrl *uctrl)
 116 {
 117         return uctrl->udev;
 118 }
 119
 120 struct udev_ctrl *udev_ctrl_ref(struct udev_ctrl *uctrl)
 121 {
 122         if (uctrl == NULL)
 123                 return NULL;
 124         uctrl->refcount++;
 125         return uctrl;
 126 }
 127
 128 void udev_ctrl_unref(struct udev_ctrl *uctrl)
 129 {
 130         if (uctrl == NULL)
 131                 return;
 132         uctrl->refcount--;
 133         if (uctrl->refcount > 0)
 134                 return;
 135         if (uctrl->sock >= 0)
 136                 close(uctrl->sock);
 137         free(uctrl);
 138 }
 139
 140 int udev_ctrl_get_fd(struct udev_ctrl *uctrl)
 141 {
 142         if (uctrl == NULL)
 143                 return -1;
 144         return uctrl->sock;
 145 }
 146
 147 static int ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf)
 148 {
 149         struct udev_ctrl_msg_wire ctrl_msg_wire;
 150         int err;
 151
 152         memset(&ctrl_msg_wire, 0x00, sizeof(struct udev_ctrl_msg_wire));
 153         strcpy(ctrl_msg_wire.version, "udev-" VERSION);
 154         ctrl_msg_wire.magic = UDEV_CTRL_MAGIC;
 155         ctrl_msg_wire.type = type;
 156
 157         if (buf != NULL)
 158                 util_strlcpy(ctrl_msg_wire.buf, buf, sizeof(ctrl_msg_wire.buf));
 159         else
 160                 ctrl_msg_wire.intval = intval;
 161
 162         err = sendto(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0,
 163                      (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 164         if (err == -1) {
 165                 err(uctrl->udev, "error sending message: %m\n");
 166         }
 167         return err;
 168 }
 169
 170 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority)
 171 {
 172         ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL);
 173         return 0;
 174 }
 175
 176 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl)
 177 {
 178         ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL);
 179         return 0;
 180 }
 181
 182 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl)
 183 {
 184         ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL);
 185         return 0;
 186 }
 187
 188 int udev_ctrl_send_reload_rules(struct udev_ctrl *uctrl)
 189 {
 190         ctrl_send(uctrl, UDEV_CTRL_RELOAD_RULES, 0, NULL);
 191         return 0;
 192 }
 193
 194 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key)
 195 {
 196         ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, key);
 197         return 0;
 198 }
 199
 200 int udev_ctrl_send_set_max_childs(struct udev_ctrl *uctrl, int count)
 201 {
 202         ctrl_send(uctrl, UDEV_CTRL_SET_MAX_CHILDS, count, NULL);
 203         return 0;
 204 }
 205
 206 struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl *uctrl)
 207 {
 208         struct udev_ctrl_msg *uctrl_msg;
 209         ssize_t size;
 210         struct msghdr smsg;
 211         struct cmsghdr *cmsg;
 212         struct iovec iov;
 213         struct ucred *cred;
 214         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 215
 216         uctrl_msg = malloc(sizeof(struct udev_ctrl_msg));
 217         if (uctrl_msg == NULL)
 218                 return NULL;
 219         memset(uctrl_msg, 0x00, sizeof(struct udev_ctrl_msg));
 220         uctrl_msg->refcount = 1;
 221         uctrl_msg->uctrl = uctrl;
 222
 223         iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 224         iov.iov_len = sizeof(struct udev_ctrl_msg_wire);
 225
 226         memset(&smsg, 0x00, sizeof(struct msghdr));
 227         smsg.msg_iov = &iov;
 228         smsg.msg_iovlen = 1;
 229         smsg.msg_control = cred_msg;
 230         smsg.msg_controllen = sizeof(cred_msg);
 231
 232         size = recvmsg(uctrl->sock, &smsg, 0);
 233         if (size <  0) {
 234                 err(uctrl->udev, "unable to receive user udevd message: %m\n");
 235                 goto err;
 236         }
 237         cmsg = CMSG_FIRSTHDR(&smsg);
 238         cred = (struct ucred *) CMSG_DATA(cmsg);
 239
 240         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 241                 err(uctrl->udev, "no sender credentials received, message ignored\n");
 242                 goto err;
 243         }
 244
 245         if (cred->uid != 0) {
 246                 err(uctrl->udev, "sender uid=%i, message ignored\n", cred->uid);
 247                 goto err;
 248         }
 249
 250         if (uctrl_msg->ctrl_msg_wire.magic != UDEV_CTRL_MAGIC) {
 251                 err(uctrl->udev, "message magic 0x%08x doesn't match, ignore it\n", uctrl_msg->ctrl_msg_wire.magic);
 252                 goto err;
 253         }
 254
 255         info(uctrl->udev, "created ctrl_msg %p (%i)\n", uctrl_msg, uctrl_msg->ctrl_msg_wire.type);
 256         return uctrl_msg;
 257 err:
 258         udev_ctrl_msg_unref(uctrl_msg);
 259         return NULL;
 260 }
 261
 262 struct udev_ctrl_msg *udev_ctrl_msg_ref(struct udev_ctrl_msg *ctrl_msg)
 263 {
 264         if (ctrl_msg == NULL)
 265                 return NULL;
 266         ctrl_msg->refcount++;
 267         return ctrl_msg;
 268 }
 269
 270 void udev_ctrl_msg_unref(struct udev_ctrl_msg *ctrl_msg)
 271 {
 272         if (ctrl_msg == NULL)
 273                 return;
 274         ctrl_msg->refcount--;
 275         if (ctrl_msg->refcount > 0)
 276                 return;
 277         info(ctrl_msg->uctrl->udev, "release ctrl_msg %p\n", ctrl_msg);
 278         free(ctrl_msg);
 279 }
 280
 281 int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg)
 282 {
 283         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_LOG_LEVEL)
 284                 return ctrl_msg->ctrl_msg_wire.intval;
 285         return -1;
 286 }
 287
 288 int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 289 {
 290         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_STOP_EXEC_QUEUE)
 291                 return 1;
 292         return -1;
 293 }
 294
 295 int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 296 {
 297         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_START_EXEC_QUEUE)
 298                 return 1;
 299         return -1;
 300 }
 301
 302 int udev_ctrl_get_reload_rules(struct udev_ctrl_msg *ctrl_msg)
 303 {
 304         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_RELOAD_RULES)
 305                 return 1;
 306         return -1;
 307 }
 308
 309 const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg)
 310 {
 311         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_ENV)
 312                 return ctrl_msg->ctrl_msg_wire.buf;
 313         return NULL;
 314 }
 315
 316 int udev_ctrl_get_set_max_childs(struct udev_ctrl_msg *ctrl_msg)
 317 {
 318         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_MAX_CHILDS)
 319                 return ctrl_msg->ctrl_msg_wire.intval;
 320         return -1;
 321 }