libudev-monitor.c revision ba6929f6690a72485ac3c6b7610ffbd5ab319be7
/*
* libudev - interface to udev device information
*
* Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <dirent.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>
#include "libudev.h"
#include "libudev-private.h"
#include "../udev.h"
struct udev_monitor {
struct udev *udev;
int refcount;
int socket;
};
struct udev_monitor *udev_monitor_new_from_socket(struct udev *udev, const char *socket_path)
{
struct udev_monitor *udev_monitor;
struct sockaddr_un saddr;
socklen_t addrlen;
const int on = 1;
if (udev == NULL)
return NULL;
if (socket_path == NULL)
return NULL;
udev_monitor = malloc(sizeof(struct udev_monitor));
if (udev_monitor == NULL)
return NULL;
memset(udev_monitor, 0x00, sizeof(struct udev_monitor));
udev_monitor->refcount = 1;
udev_monitor->udev = udev;
memset(&saddr, 0x00, sizeof(saddr));
saddr.sun_family = AF_LOCAL;
strcpy(saddr.sun_path, socket_path);
addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path);
/* translate leading '@' to abstract namespace */
if (saddr.sun_path[0] == '@')
saddr.sun_path[0] = '\0';
udev_monitor->socket = socket(AF_LOCAL, SOCK_DGRAM, 0);
if (udev_monitor->socket == -1) {
log_err(udev, "error getting socket: %s\n", strerror(errno));
free(udev_monitor);
return NULL;
}
if (bind(udev_monitor->socket, (struct sockaddr *) &saddr, addrlen) < 0) {
log_err(udev, "bind failed: %s\n", strerror(errno));
close(udev_monitor->socket);
free(udev_monitor);
return NULL;
}
/* enable receiving of the sender credentials */
setsockopt(udev_monitor->socket, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
log_info(udev_monitor->udev, "udev_monitor: %p created\n", udev_monitor);
return udev_monitor;
}
struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor)
{
if (udev_monitor == NULL)
return NULL;
udev_monitor->refcount++;
return udev_monitor;
}
void udev_monitor_unref(struct udev_monitor *udev_monitor)
{
if (udev_monitor == NULL)
return;
udev_monitor->refcount--;
if (udev_monitor->refcount > 0)
return;
close(udev_monitor->socket);
log_info(udev_monitor->udev, "udev_monitor: %p released\n", udev_monitor);
free(udev_monitor);
}
struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor)
{
if (udev_monitor == NULL)
return NULL;
return udev_monitor->udev;
}
int udev_monitor_get_fd(struct udev_monitor *udev_monitor)
{
if (udev_monitor == NULL)
return -1;
return udev_monitor->socket;
}
struct udev_device *udev_monitor_get_device(struct udev_monitor *udev_monitor)
{
struct udev_device *udev_device;
struct msghdr smsg;
struct cmsghdr *cmsg;
struct iovec iov;
struct ucred *cred;
char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
char buf[4096];
size_t bufpos;
if (udev_monitor == NULL)
return NULL;
memset(buf, 0x00, sizeof(buf));
iov.iov_base = &buf;
iov.iov_len = sizeof(buf);
memset (&smsg, 0x00, sizeof(struct msghdr));
smsg.msg_iov = &iov;
smsg.msg_iovlen = 1;
smsg.msg_control = cred_msg;
smsg.msg_controllen = sizeof(cred_msg);
if (recvmsg(udev_monitor->socket, &smsg, 0) < 0) {
if (errno != EINTR)
log_info(udev_monitor->udev, "unable to receive message");
return NULL;
}
cmsg = CMSG_FIRSTHDR(&smsg);
cred = (struct ucred *)CMSG_DATA (cmsg);
if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
log_info(udev_monitor->udev, "no sender credentials received, message ignored");
return NULL;
}
if (cred->uid != 0) {
log_info(udev_monitor->udev, "sender uid=%d, message ignored", cred->uid);
return NULL;
}
/* skip header */
bufpos = strlen(buf) + 1;
if (bufpos < sizeof("a@/d") || bufpos >= sizeof(buf)) {
log_info(udev_monitor->udev, "invalid message length");
return NULL;
}
/* check message header */
if (strstr(buf, "@/") == NULL) {
log_info(udev_monitor->udev, "unrecognized message header");
return NULL;
}
udev_device = device_init(udev_monitor->udev);
if (udev_device == NULL) {
return NULL;
}
while (bufpos < sizeof(buf)) {
char *key;
size_t keylen;
key = &buf[bufpos];
keylen = strlen(key);
if (keylen == 0)
break;
bufpos += keylen + 1;
if (strncmp(key, "DEVPATH=", 8) == 0) {
udev_device->devpath = strdup(&key[8]);
} else if (strncmp(key, "SUBSYSTEM=", 10) == 0) {
udev_device->subsystem = strdup(&key[10]);
} else if (strncmp(key, "DEVNAME=", 8) == 0) {
udev_device->devname = strdup(&key[8]);
} else if (strncmp(key, "DEVLINKS=", 9) == 0) {
char *slink = &key[9];
char *next = strchr(slink, ' ');
while (next != NULL) {
next[0] = '\0';
name_list_add(&udev_device->link_list, slink, 0);
slink = &next[1];
next = strchr(slink, ' ');
}
if (slink[0] != '\0')
name_list_add(&udev_device->link_list, slink, 0);
}
name_list_add(&udev_device->env_list, key, 0);
}
return udev_device;
}