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_CHILDREN_MAX,
  36         UDEV_CTRL_SETTLE,
  37 };
  38
  39 struct udev_ctrl_msg_wire {
  40         char version[16];
  41         unsigned int magic;
  42         enum udev_ctrl_msg_type type;
  43         union {
  44                 int intval;
  45                 char buf[256];
  46         };
  47 };
  48
  49 struct udev_ctrl_msg {
  50         int refcount;
  51         struct udev_ctrl *uctrl;
  52         struct udev_ctrl_msg_wire ctrl_msg_wire;
  53         pid_t pid;
  54 };
  55
  56 struct udev_ctrl {
  57         int refcount;
  58         struct udev *udev;
  59         int sock;
  60         struct sockaddr_un saddr;
  61         socklen_t addrlen;
  62 };
  63
  64 struct udev_ctrl *udev_ctrl_new_from_socket(struct udev *udev, const char *socket_path)
  65 {
  66         struct udev_ctrl *uctrl;
  67
  68         uctrl = calloc(1, sizeof(struct udev_ctrl));
  69         if (uctrl == NULL)
  70                 return NULL;
  71         uctrl->refcount = 1;
  72         uctrl->udev = udev;
  73
  74         uctrl->sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
  75         if (uctrl->sock < 0) {
  76                 err(udev, "error getting socket: %m\n");
  77                 udev_ctrl_unref(uctrl);
  78                 return NULL;
  79         }
  80
  81         uctrl->saddr.sun_family = AF_LOCAL;
  82         strcpy(uctrl->saddr.sun_path, socket_path);
  83         uctrl->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(uctrl->saddr.sun_path);
  84         /* translate leading '@' to abstract namespace */
  85         if (uctrl->saddr.sun_path[0] == '@')
  86                 uctrl->saddr.sun_path[0] = '\0';
  87
  88         return uctrl;
  89 }
  90
  91 int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl)
  92 {
  93         int err;
  94         const int feature_on = 1;
  95
  96         err= bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
  97         if (err < 0) {
  98                 err(uctrl->udev, "bind failed: %m\n");
  99                 return err;
 100         }
 101
 102         /* enable receiving of the sender credentials */
 103         setsockopt(uctrl->sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 104         return 0;
 105 }
 106
 107 struct udev *udev_ctrl_get_udev(struct udev_ctrl *uctrl)
 108 {
 109         return uctrl->udev;
 110 }
 111
 112 struct udev_ctrl *udev_ctrl_ref(struct udev_ctrl *uctrl)
 113 {
 114         if (uctrl == NULL)
 115                 return NULL;
 116         uctrl->refcount++;
 117         return uctrl;
 118 }
 119
 120 void udev_ctrl_unref(struct udev_ctrl *uctrl)
 121 {
 122         if (uctrl == NULL)
 123                 return;
 124         uctrl->refcount--;
 125         if (uctrl->refcount > 0)
 126                 return;
 127         if (uctrl->sock >= 0)
 128                 close(uctrl->sock);
 129         free(uctrl);
 130 }
 131
 132 int udev_ctrl_get_fd(struct udev_ctrl *uctrl)
 133 {
 134         if (uctrl == NULL)
 135                 return -1;
 136         return uctrl->sock;
 137 }
 138
 139 static int ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf)
 140 {
 141         struct udev_ctrl_msg_wire ctrl_msg_wire;
 142         int err;
 143
 144         memset(&ctrl_msg_wire, 0x00, sizeof(struct udev_ctrl_msg_wire));
 145         strcpy(ctrl_msg_wire.version, "udev-" VERSION);
 146         ctrl_msg_wire.magic = UDEV_CTRL_MAGIC;
 147         ctrl_msg_wire.type = type;
 148
 149         if (buf != NULL)
 150                 util_strscpy(ctrl_msg_wire.buf, sizeof(ctrl_msg_wire.buf), buf);
 151         else
 152                 ctrl_msg_wire.intval = intval;
 153
 154         err = sendto(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0,
 155                      (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 156         if (err == -1) {
 157                 err(uctrl->udev, "error sending message: %m\n");
 158         }
 159         return err;
 160 }
 161
 162 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority)
 163 {
 164         return ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL);
 165 }
 166
 167 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl)
 168 {
 169         return ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL);
 170 }
 171
 172 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl)
 173 {
 174         return ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL);
 175 }
 176
 177 int udev_ctrl_send_reload_rules(struct udev_ctrl *uctrl)
 178 {
 179         return ctrl_send(uctrl, UDEV_CTRL_RELOAD_RULES, 0, NULL);
 180 }
 181
 182 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key)
 183 {
 184         return ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, key);
 185 }
 186
 187 int udev_ctrl_send_set_children_max(struct udev_ctrl *uctrl, int count)
 188 {
 189         return ctrl_send(uctrl, UDEV_CTRL_SET_CHILDREN_MAX, count, NULL);
 190 }
 191
 192 int udev_ctrl_send_settle(struct udev_ctrl *uctrl)
 193 {
 194         return ctrl_send(uctrl, UDEV_CTRL_SETTLE, 0, NULL);
 195 }
 196
 197 struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl *uctrl)
 198 {
 199         struct udev_ctrl_msg *uctrl_msg;
 200         ssize_t size;
 201         struct msghdr smsg;
 202         struct cmsghdr *cmsg;
 203         struct iovec iov;
 204         struct ucred *cred;
 205         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 206
 207         uctrl_msg = calloc(1, sizeof(struct udev_ctrl_msg));
 208         if (uctrl_msg == NULL)
 209                 return NULL;
 210         uctrl_msg->refcount = 1;
 211         uctrl_msg->uctrl = uctrl;
 212
 213         iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 214         iov.iov_len = sizeof(struct udev_ctrl_msg_wire);
 215
 216         memset(&smsg, 0x00, sizeof(struct msghdr));
 217         smsg.msg_iov = &iov;
 218         smsg.msg_iovlen = 1;
 219         smsg.msg_control = cred_msg;
 220         smsg.msg_controllen = sizeof(cred_msg);
 221
 222         size = recvmsg(uctrl->sock, &smsg, 0);
 223         if (size <  0) {
 224                 err(uctrl->udev, "unable to receive user udevd message: %m\n");
 225                 goto err;
 226         }
 227         cmsg = CMSG_FIRSTHDR(&smsg);
 228         cred = (struct ucred *) CMSG_DATA(cmsg);
 229
 230         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 231                 err(uctrl->udev, "no sender credentials received, message ignored\n");
 232                 goto err;
 233         }
 234
 235         if (cred->uid != 0) {
 236                 err(uctrl->udev, "sender uid=%i, message ignored\n", cred->uid);
 237                 goto err;
 238         }
 239
 240         uctrl_msg->pid = cred->pid;
 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_children_max(struct udev_ctrl_msg *ctrl_msg)
 309 {
 310         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_CHILDREN_MAX)
 311                 return ctrl_msg->ctrl_msg_wire.intval;
 312         return -1;
 313 }
 314
 315 pid_t udev_ctrl_get_settle(struct udev_ctrl_msg *ctrl_msg)
 316 {
 317         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SETTLE)
 318                 return ctrl_msg->pid;
 319         return -1;
 320 }