libudev/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 library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <errno.h>
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <stddef.h>
  16 #include <string.h>
  17 #include <unistd.h>
  18 #include <sys/types.h>
  19 #include <sys/socket.h>
  20 #include <sys/un.h>
  21
  22 #include "libudev.h"
  23 #include "libudev-private.h"
  24
  25 /* wire protocol magic must match */
  26 #define UDEV_CTRL_MAGIC                         0xdead1dea
  27
  28 enum udev_ctrl_msg_type {
  29         UDEV_CTRL_UNKNOWN,
  30         UDEV_CTRL_SET_LOG_LEVEL,
  31         UDEV_CTRL_STOP_EXEC_QUEUE,
  32         UDEV_CTRL_START_EXEC_QUEUE,
  33         UDEV_CTRL_RELOAD_RULES,
  34         UDEV_CTRL_SET_ENV,
  35         UDEV_CTRL_SET_MAX_CHILDS,
  36         UDEV_CTRL_SET_MAX_CHILDS_RUNNING,
  37         UDEV_CTRL_SETTLE,
  38 };
  39
  40 struct udev_ctrl_msg_wire {
  41         char version[16];
  42         unsigned int magic;
  43         enum udev_ctrl_msg_type type;
  44         union {
  45                 int intval;
  46                 char buf[256];
  47         };
  48 };
  49
  50 struct udev_ctrl_msg {
  51         int refcount;
  52         struct udev_ctrl *uctrl;
  53         struct udev_ctrl_msg_wire ctrl_msg_wire;
  54         pid_t pid;
  55 };
  56
  57 struct udev_ctrl {
  58         int refcount;
  59         struct udev *udev;
  60         int sock;
  61         struct sockaddr_un saddr;
  62         socklen_t addrlen;
  63 };
  64
  65 struct udev_ctrl *udev_ctrl_new_from_socket(struct udev *udev, const char *socket_path)
  66 {
  67         struct udev_ctrl *uctrl;
  68
  69         uctrl = calloc(1, sizeof(struct udev_ctrl));
  70         if (uctrl == NULL)
  71                 return NULL;
  72         uctrl->refcount = 1;
  73         uctrl->udev = udev;
  74
  75         uctrl->sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
  76         if (uctrl->sock < 0) {
  77                 err(udev, "error getting socket: %m\n");
  78                 udev_ctrl_unref(uctrl);
  79                 return NULL;
  80         }
  81
  82         uctrl->saddr.sun_family = AF_LOCAL;
  83         strcpy(uctrl->saddr.sun_path, socket_path);
  84         uctrl->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(uctrl->saddr.sun_path);
  85         /* translate leading '@' to abstract namespace */
  86         if (uctrl->saddr.sun_path[0] == '@')
  87                 uctrl->saddr.sun_path[0] = '\0';
  88
  89         return uctrl;
  90 }
  91
  92 int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl)
  93 {
  94         int err;
  95         const int feature_on = 1;
  96
  97         err= bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
  98         if (err < 0) {
  99                 err(uctrl->udev, "bind failed: %m\n");
 100                 return err;
 101         }
 102
 103         /* enable receiving of the sender credentials */
 104         setsockopt(uctrl->sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 105         return 0;
 106 }
 107
 108 struct udev *udev_ctrl_get_udev(struct udev_ctrl *uctrl)
 109 {
 110         return uctrl->udev;
 111 }
 112
 113 struct udev_ctrl *udev_ctrl_ref(struct udev_ctrl *uctrl)
 114 {
 115         if (uctrl == NULL)
 116                 return NULL;
 117         uctrl->refcount++;
 118         return uctrl;
 119 }
 120
 121 void udev_ctrl_unref(struct udev_ctrl *uctrl)
 122 {
 123         if (uctrl == NULL)
 124                 return;
 125         uctrl->refcount--;
 126         if (uctrl->refcount > 0)
 127                 return;
 128         if (uctrl->sock >= 0)
 129                 close(uctrl->sock);
 130         free(uctrl);
 131 }
 132
 133 int udev_ctrl_get_fd(struct udev_ctrl *uctrl)
 134 {
 135         if (uctrl == NULL)
 136                 return -1;
 137         return uctrl->sock;
 138 }
 139
 140 static int ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf)
 141 {
 142         struct udev_ctrl_msg_wire ctrl_msg_wire;
 143         int err;
 144
 145         memset(&ctrl_msg_wire, 0x00, sizeof(struct udev_ctrl_msg_wire));
 146         strcpy(ctrl_msg_wire.version, "udev-" VERSION);
 147         ctrl_msg_wire.magic = UDEV_CTRL_MAGIC;
 148         ctrl_msg_wire.type = type;
 149
 150         if (buf != NULL)
 151                 util_strscpy(ctrl_msg_wire.buf, sizeof(ctrl_msg_wire.buf), buf);
 152         else
 153                 ctrl_msg_wire.intval = intval;
 154
 155         err = sendto(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0,
 156                      (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 157         if (err == -1) {
 158                 err(uctrl->udev, "error sending message: %m\n");
 159         }
 160         return err;
 161 }
 162
 163 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority)
 164 {
 165         return ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL);
 166 }
 167
 168 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl)
 169 {
 170         return ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL);
 171 }
 172
 173 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl)
 174 {
 175         return ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL);
 176 }
 177
 178 int udev_ctrl_send_reload_rules(struct udev_ctrl *uctrl)
 179 {
 180         return ctrl_send(uctrl, UDEV_CTRL_RELOAD_RULES, 0, NULL);
 181 }
 182
 183 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key)
 184 {
 185         return ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, key);
 186 }
 187
 188 int udev_ctrl_send_set_max_childs(struct udev_ctrl *uctrl, int count)
 189 {
 190         return ctrl_send(uctrl, UDEV_CTRL_SET_MAX_CHILDS, count, NULL);
 191 }
 192
 193 int udev_ctrl_send_settle(struct udev_ctrl *uctrl)
 194 {
 195         return ctrl_send(uctrl, UDEV_CTRL_SETTLE, 0, NULL);
 196 }
 197
 198 struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl *uctrl)
 199 {
 200         struct udev_ctrl_msg *uctrl_msg;
 201         ssize_t size;
 202         struct msghdr smsg;
 203         struct cmsghdr *cmsg;
 204         struct iovec iov;
 205         struct ucred *cred;
 206         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 207
 208         uctrl_msg = calloc(1, sizeof(struct udev_ctrl_msg));
 209         if (uctrl_msg == NULL)
 210                 return NULL;
 211         uctrl_msg->refcount = 1;
 212         uctrl_msg->uctrl = uctrl;
 213
 214         iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 215         iov.iov_len = sizeof(struct udev_ctrl_msg_wire);
 216
 217         memset(&smsg, 0x00, sizeof(struct msghdr));
 218         smsg.msg_iov = &iov;
 219         smsg.msg_iovlen = 1;
 220         smsg.msg_control = cred_msg;
 221         smsg.msg_controllen = sizeof(cred_msg);
 222
 223         size = recvmsg(uctrl->sock, &smsg, 0);
 224         if (size <  0) {
 225                 err(uctrl->udev, "unable to receive user udevd message: %m\n");
 226                 goto err;
 227         }
 228         cmsg = CMSG_FIRSTHDR(&smsg);
 229         cred = (struct ucred *) CMSG_DATA(cmsg);
 230
 231         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 232                 err(uctrl->udev, "no sender credentials received, message ignored\n");
 233                 goto err;
 234         }
 235
 236         if (cred->uid != 0) {
 237                 err(uctrl->udev, "sender uid=%i, message ignored\n", cred->uid);
 238                 goto err;
 239         }
 240
 241         uctrl_msg->pid = cred->pid;
 242
 243         if (uctrl_msg->ctrl_msg_wire.magic != UDEV_CTRL_MAGIC) {
 244                 err(uctrl->udev, "message magic 0x%08x doesn't match, ignore it\n", uctrl_msg->ctrl_msg_wire.magic);
 245                 goto err;
 246         }
 247
 248         dbg(uctrl->udev, "created ctrl_msg %p (%i)\n", uctrl_msg, uctrl_msg->ctrl_msg_wire.type);
 249         return uctrl_msg;
 250 err:
 251         udev_ctrl_msg_unref(uctrl_msg);
 252         return NULL;
 253 }
 254
 255 struct udev_ctrl_msg *udev_ctrl_msg_ref(struct udev_ctrl_msg *ctrl_msg)
 256 {
 257         if (ctrl_msg == NULL)
 258                 return NULL;
 259         ctrl_msg->refcount++;
 260         return ctrl_msg;
 261 }
 262
 263 void udev_ctrl_msg_unref(struct udev_ctrl_msg *ctrl_msg)
 264 {
 265         if (ctrl_msg == NULL)
 266                 return;
 267         ctrl_msg->refcount--;
 268         if (ctrl_msg->refcount > 0)
 269                 return;
 270         dbg(ctrl_msg->uctrl->udev, "release ctrl_msg %p\n", ctrl_msg);
 271         free(ctrl_msg);
 272 }
 273
 274 int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg)
 275 {
 276         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_LOG_LEVEL)
 277                 return ctrl_msg->ctrl_msg_wire.intval;
 278         return -1;
 279 }
 280
 281 int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 282 {
 283         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_STOP_EXEC_QUEUE)
 284                 return 1;
 285         return -1;
 286 }
 287
 288 int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 289 {
 290         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_START_EXEC_QUEUE)
 291                 return 1;
 292         return -1;
 293 }
 294
 295 int udev_ctrl_get_reload_rules(struct udev_ctrl_msg *ctrl_msg)
 296 {
 297         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_RELOAD_RULES)
 298                 return 1;
 299         return -1;
 300 }
 301
 302 const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg)
 303 {
 304         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_ENV)
 305                 return ctrl_msg->ctrl_msg_wire.buf;
 306         return NULL;
 307 }
 308
 309 int udev_ctrl_get_set_max_childs(struct udev_ctrl_msg *ctrl_msg)
 310 {
 311         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_MAX_CHILDS)
 312                 return ctrl_msg->ctrl_msg_wire.intval;
 313         return -1;
 314 }
 315
 316 pid_t udev_ctrl_get_settle(struct udev_ctrl_msg *ctrl_msg)
 317 {
 318         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SETTLE)
 319                 return ctrl_msg->pid;
 320         return -1;
 321 }