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         UDEV_CTRL_SETTLE,
  46 };
  47
  48 struct udev_ctrl_msg_wire {
  49         char version[16];
  50         unsigned int magic;
  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 udev_ctrl_msg_wire ctrl_msg_wire;
  62         pid_t pid;
  63 };
  64
  65 struct udev_ctrl {
  66         int refcount;
  67         struct udev *udev;
  68         int sock;
  69         struct sockaddr_un saddr;
  70         socklen_t addrlen;
  71 };
  72
  73 struct udev_ctrl *udev_ctrl_new_from_socket(struct udev *udev, const char *socket_path)
  74 {
  75         struct udev_ctrl *uctrl;
  76
  77         uctrl = calloc(1, sizeof(struct udev_ctrl));
  78         if (uctrl == NULL)
  79                 return NULL;
  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: %m\n");
  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: %m\n");
 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 udev_ctrl_msg_wire ctrl_msg_wire;
 151         int err;
 152
 153         memset(&ctrl_msg_wire, 0x00, sizeof(struct udev_ctrl_msg_wire));
 154         strcpy(ctrl_msg_wire.version, "udev-" VERSION);
 155         ctrl_msg_wire.magic = UDEV_CTRL_MAGIC;
 156         ctrl_msg_wire.type = type;
 157
 158         if (buf != NULL)
 159                 util_strlcpy(ctrl_msg_wire.buf, buf, sizeof(ctrl_msg_wire.buf));
 160         else
 161                 ctrl_msg_wire.intval = intval;
 162
 163         err = sendto(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0,
 164                      (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 165         if (err == -1) {
 166                 err(uctrl->udev, "error sending message: %m\n");
 167         }
 168         return err;
 169 }
 170
 171 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority)
 172 {
 173         return ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL);
 174 }
 175
 176 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl)
 177 {
 178         return ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL);
 179 }
 180
 181 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl)
 182 {
 183         return ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL);
 184 }
 185
 186 int udev_ctrl_send_reload_rules(struct udev_ctrl *uctrl)
 187 {
 188         return ctrl_send(uctrl, UDEV_CTRL_RELOAD_RULES, 0, NULL);
 189 }
 190
 191 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key)
 192 {
 193         return ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, key);
 194 }
 195
 196 int udev_ctrl_send_set_max_childs(struct udev_ctrl *uctrl, int count)
 197 {
 198         return ctrl_send(uctrl, UDEV_CTRL_SET_MAX_CHILDS, count, NULL);
 199 }
 200
 201 int udev_ctrl_send_settle(struct udev_ctrl *uctrl)
 202 {
 203         return ctrl_send(uctrl, UDEV_CTRL_SETTLE, 0, NULL);
 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 = calloc(1, sizeof(struct udev_ctrl_msg));
 217         if (uctrl_msg == NULL)
 218                 return NULL;
 219         uctrl_msg->refcount = 1;
 220         uctrl_msg->uctrl = uctrl;
 221
 222         iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 223         iov.iov_len = sizeof(struct udev_ctrl_msg_wire);
 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: %m\n");
 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         uctrl_msg->pid = cred->pid;
 250
 251         if (uctrl_msg->ctrl_msg_wire.magic != UDEV_CTRL_MAGIC) {
 252                 err(uctrl->udev, "message magic 0x%08x doesn't match, ignore it\n", uctrl_msg->ctrl_msg_wire.magic);
 253                 goto err;
 254         }
 255
 256         dbg(uctrl->udev, "created ctrl_msg %p (%i)\n", uctrl_msg, uctrl_msg->ctrl_msg_wire.type);
 257         return uctrl_msg;
 258 err:
 259         udev_ctrl_msg_unref(uctrl_msg);
 260         return NULL;
 261 }
 262
 263 struct udev_ctrl_msg *udev_ctrl_msg_ref(struct udev_ctrl_msg *ctrl_msg)
 264 {
 265         if (ctrl_msg == NULL)
 266                 return NULL;
 267         ctrl_msg->refcount++;
 268         return ctrl_msg;
 269 }
 270
 271 void udev_ctrl_msg_unref(struct udev_ctrl_msg *ctrl_msg)
 272 {
 273         if (ctrl_msg == NULL)
 274                 return;
 275         ctrl_msg->refcount--;
 276         if (ctrl_msg->refcount > 0)
 277                 return;
 278         dbg(ctrl_msg->uctrl->udev, "release ctrl_msg %p\n", ctrl_msg);
 279         free(ctrl_msg);
 280 }
 281
 282 int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg)
 283 {
 284         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_LOG_LEVEL)
 285                 return ctrl_msg->ctrl_msg_wire.intval;
 286         return -1;
 287 }
 288
 289 int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 290 {
 291         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_STOP_EXEC_QUEUE)
 292                 return 1;
 293         return -1;
 294 }
 295
 296 int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 297 {
 298         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_START_EXEC_QUEUE)
 299                 return 1;
 300         return -1;
 301 }
 302
 303 int udev_ctrl_get_reload_rules(struct udev_ctrl_msg *ctrl_msg)
 304 {
 305         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_RELOAD_RULES)
 306                 return 1;
 307         return -1;
 308 }
 309
 310 const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg)
 311 {
 312         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_ENV)
 313                 return ctrl_msg->ctrl_msg_wire.buf;
 314         return NULL;
 315 }
 316
 317 int udev_ctrl_get_set_max_childs(struct udev_ctrl_msg *ctrl_msg)
 318 {
 319         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_MAX_CHILDS)
 320                 return ctrl_msg->ctrl_msg_wire.intval;
 321         return -1;
 322 }
 323
 324 pid_t udev_ctrl_get_settle(struct udev_ctrl_msg *ctrl_msg)
 325 {
 326         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SETTLE)
 327                 return ctrl_msg->pid;
 328         return -1;
 329 }