libudev: add udev event monitor API

1 files changed, 216 insertions, 0 deletions

diff --git a/udev/lib/libudev-monitor.c b/udev/lib/libudev-monitor.c
new file mode 100644
index 0000000000..fbb21d04ea
--- /dev/null
+++ b/udev/lib/libudev-monitor.c
@@ -0,0 +1,216 @@
+/*
+ * 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;
+}