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 = calloc(1, sizeof(struct udev_ctrl));
  76         if (uctrl == NULL)
  77                 return NULL;
  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 udev_ctrl_msg_wire ctrl_msg_wire;
 149         int err;
 150
 151         memset(&ctrl_msg_wire, 0x00, sizeof(struct udev_ctrl_msg_wire));
 152         strcpy(ctrl_msg_wire.version, "udev-" VERSION);
 153         ctrl_msg_wire.magic = UDEV_CTRL_MAGIC;
 154         ctrl_msg_wire.type = type;
 155
 156         if (buf != NULL)
 157                 util_strlcpy(ctrl_msg_wire.buf, buf, sizeof(ctrl_msg_wire.buf));
 158         else
 159                 ctrl_msg_wire.intval = intval;
 160
 161         err = sendto(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0,
 162                      (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 163         if (err == -1) {
 164                 err(uctrl->udev, "error sending message: %m\n");
 165         }
 166         return err;
 167 }
 168
 169 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority)
 170 {
 171         return ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL);
 172 }
 173
 174 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl)
 175 {
 176         return ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL);
 177 }
 178
 179 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl)
 180 {
 181         return ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL);
 182 }
 183
 184 int udev_ctrl_send_reload_rules(struct udev_ctrl *uctrl)
 185 {
 186         return ctrl_send(uctrl, UDEV_CTRL_RELOAD_RULES, 0, NULL);
 187 }
 188
 189 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key)
 190 {
 191         return ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, key);
 192 }
 193
 194 int udev_ctrl_send_set_max_childs(struct udev_ctrl *uctrl, int count)
 195 {
 196         return ctrl_send(uctrl, UDEV_CTRL_SET_MAX_CHILDS, count, NULL);
 197 }
 198
 199 struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl *uctrl)
 200 {
 201         struct udev_ctrl_msg *uctrl_msg;
 202         ssize_t size;
 203         struct msghdr smsg;
 204         struct cmsghdr *cmsg;
 205         struct iovec iov;
 206         struct ucred *cred;
 207         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 208
 209         uctrl_msg = calloc(1, sizeof(struct udev_ctrl_msg));
 210         if (uctrl_msg == NULL)
 211                 return NULL;
 212         uctrl_msg->refcount = 1;
 213         uctrl_msg->uctrl = uctrl;
 214
 215         iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 216         iov.iov_len = sizeof(struct udev_ctrl_msg_wire);
 217
 218         memset(&smsg, 0x00, sizeof(struct msghdr));
 219         smsg.msg_iov = &iov;
 220         smsg.msg_iovlen = 1;
 221         smsg.msg_control = cred_msg;
 222         smsg.msg_controllen = sizeof(cred_msg);
 223
 224         size = recvmsg(uctrl->sock, &smsg, 0);
 225         if (size <  0) {
 226                 err(uctrl->udev, "unable to receive user udevd message: %m\n");
 227                 goto err;
 228         }
 229         cmsg = CMSG_FIRSTHDR(&smsg);
 230         cred = (struct ucred *) CMSG_DATA(cmsg);
 231
 232         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 233                 err(uctrl->udev, "no sender credentials received, message ignored\n");
 234                 goto err;
 235         }
 236
 237         if (cred->uid != 0) {
 238                 err(uctrl->udev, "sender uid=%i, message ignored\n", cred->uid);
 239                 goto err;
 240         }
 241
 242         if (uctrl_msg->ctrl_msg_wire.magic != UDEV_CTRL_MAGIC) {
 243                 err(uctrl->udev, "message magic 0x%08x doesn't match, ignore it\n", uctrl_msg->ctrl_msg_wire.magic);
 244                 goto err;
 245         }
 246
 247         dbg(uctrl->udev, "created ctrl_msg %p (%i)\n", uctrl_msg, uctrl_msg->ctrl_msg_wire.type);
 248         return uctrl_msg;
 249 err:
 250         udev_ctrl_msg_unref(uctrl_msg);
 251         return NULL;
 252 }
 253
 254 struct udev_ctrl_msg *udev_ctrl_msg_ref(struct udev_ctrl_msg *ctrl_msg)
 255 {
 256         if (ctrl_msg == NULL)
 257                 return NULL;
 258         ctrl_msg->refcount++;
 259         return ctrl_msg;
 260 }
 261
 262 void udev_ctrl_msg_unref(struct udev_ctrl_msg *ctrl_msg)
 263 {
 264         if (ctrl_msg == NULL)
 265                 return;
 266         ctrl_msg->refcount--;
 267         if (ctrl_msg->refcount > 0)
 268                 return;
 269         dbg(ctrl_msg->uctrl->udev, "release ctrl_msg %p\n", ctrl_msg);
 270         free(ctrl_msg);
 271 }
 272
 273 int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg)
 274 {
 275         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_LOG_LEVEL)
 276                 return ctrl_msg->ctrl_msg_wire.intval;
 277         return -1;
 278 }
 279
 280 int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 281 {
 282         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_STOP_EXEC_QUEUE)
 283                 return 1;
 284         return -1;
 285 }
 286
 287 int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 288 {
 289         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_START_EXEC_QUEUE)
 290                 return 1;
 291         return -1;
 292 }
 293
 294 int udev_ctrl_get_reload_rules(struct udev_ctrl_msg *ctrl_msg)
 295 {
 296         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_RELOAD_RULES)
 297                 return 1;
 298         return -1;
 299 }
 300
 301 const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg)
 302 {
 303         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_ENV)
 304                 return ctrl_msg->ctrl_msg_wire.buf;
 305         return NULL;
 306 }
 307
 308 int udev_ctrl_get_set_max_childs(struct udev_ctrl_msg *ctrl_msg)
 309 {
 310         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_MAX_CHILDS)
 311                 return ctrl_msg->ctrl_msg_wire.intval;
 312         return -1;
 313 }