Tools: hv: vss: use misc char device to communicate with kernel (f5722b9b) · Commits · e / devices / android_kernel_fairphone_FP4

tools/hv/hv_vss_daemon.c

+25 −114

Original line number	Diff line number	Diff line
		@@ -19,7 +19,6 @@


		#include <sys/types.h>
		#include <sys/socket.h>
		#include <sys/poll.h>
		#include <sys/ioctl.h>
		#include <fcntl.h>
		@@ -30,21 +29,11 @@
		#include <string.h>
		#include <ctype.h>
		#include <errno.h>
		#include <arpa/inet.h>
		#include <linux/fs.h>
		#include <linux/connector.h>
		#include <linux/hyperv.h>
		#include <linux/netlink.h>
		#include <syslog.h>
		#include <getopt.h>

		static struct sockaddr_nl addr;

		#ifndef SOL_NETLINK
		#define SOL_NETLINK 270
		#endif


		/* Don't use syslog() in the function since that can cause write to disk */
		static int vss_do_freeze(char *dir, unsigned int cmd)
		{
		@@ -143,33 +132,6 @@ static int vss_operate(int operation)
		return error;
		}

		static int netlink_send(int fd, struct cn_msg *msg)
		{
		struct nlmsghdr nlh = { .nlmsg_type = NLMSG_DONE };
		unsigned int size;
		struct msghdr message;
		struct iovec iov[2];

		size = sizeof(struct cn_msg) + msg->len;

		nlh.nlmsg_pid = getpid();
		nlh.nlmsg_len = NLMSG_LENGTH(size);

		iov[0].iov_base = &nlh;
		iov[0].iov_len = sizeof(nlh);

		iov[1].iov_base = msg;
		iov[1].iov_len = size;

		memset(&message, 0, sizeof(message));
		message.msg_name = &addr;
		message.msg_namelen = sizeof(addr);
		message.msg_iov = iov;
		message.msg_iovlen = 2;

		return sendmsg(fd, &message, 0);
		}

		void print_usage(char *argv[])
		{
		fprintf(stderr, "Usage: %s [options]\n"
		@@ -180,16 +142,11 @@ void print_usage(char *argv[])

		int main(int argc, char *argv[])
		{
		int fd, len, nl_group;
		int vss_fd, len;
		int error;
		struct cn_msg *message;
		struct pollfd pfd;
		struct nlmsghdr *incoming_msg;
		struct cn_msg *incoming_cn_msg;
		int op;
		struct hv_vss_msg *vss_msg;
		char *vss_recv_buffer;
		size_t vss_recv_buffer_len;
		struct hv_vss_msg vss_msg[1];
		int daemonize = 1, long_index = 0, opt;

		static struct option long_options[] = {
		@@ -217,98 +174,50 @@ int main(int argc, char *argv[])
		openlog("Hyper-V VSS", 0, LOG_USER);
		syslog(LOG_INFO, "VSS starting; pid is:%d", getpid());

		vss_recv_buffer_len = NLMSG_LENGTH(0) + sizeof(struct cn_msg) + sizeof(struct hv_vss_msg);
		vss_recv_buffer = calloc(1, vss_recv_buffer_len);
		if (!vss_recv_buffer) {
		syslog(LOG_ERR, "Failed to allocate netlink buffers");
		exit(EXIT_FAILURE);
		}

		fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
		if (fd < 0) {
		syslog(LOG_ERR, "netlink socket creation failed; error:%d %s",
		vss_fd = open("/dev/vmbus/hv_vss", O_RDWR);
		if (vss_fd < 0) {
		syslog(LOG_ERR, "open /dev/vmbus/hv_vss failed; error: %d %s",
		errno, strerror(errno));
		exit(EXIT_FAILURE);
		}
		addr.nl_family = AF_NETLINK;
		addr.nl_pad = 0;
		addr.nl_pid = 0;
		addr.nl_groups = 0;


		error = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
		if (error < 0) {
		syslog(LOG_ERR, "bind failed; error:%d %s", errno, strerror(errno));
		close(fd);
		exit(EXIT_FAILURE);
		}
		nl_group = CN_VSS_IDX;
		if (setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &nl_group, sizeof(nl_group)) < 0) {
		syslog(LOG_ERR, "setsockopt failed; error:%d %s", errno, strerror(errno));
		close(fd);
		exit(EXIT_FAILURE);
		}
		/*
		* Register ourselves with the kernel.
		*/
		message = (struct cn_msg *)vss_recv_buffer;
		message->id.idx = CN_VSS_IDX;
		message->id.val = CN_VSS_VAL;
		message->ack = 0;
		vss_msg = (struct hv_vss_msg *)message->data;
		vss_msg->vss_hdr.operation = VSS_OP_REGISTER;
		vss_msg->vss_hdr.operation = VSS_OP_REGISTER1;

		message->len = sizeof(struct hv_vss_msg);

		len = netlink_send(fd, message);
		len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
		if (len < 0) {
		syslog(LOG_ERR, "netlink_send failed; error:%d %s", errno, strerror(errno));
		close(fd);
		syslog(LOG_ERR, "registration to kernel failed; error: %d %s",
		errno, strerror(errno));
		close(vss_fd);
		exit(EXIT_FAILURE);
		}

		pfd.fd = fd;
		pfd.fd = vss_fd;

		while (1) {
		struct sockaddr addr_p = (struct sockaddr ) &addr;
		socklen_t addr_l = sizeof(addr);
		pfd.events = POLLIN;
		pfd.revents = 0;

		if (poll(&pfd, 1, -1) < 0) {
		syslog(LOG_ERR, "poll failed; error:%d %s", errno, strerror(errno));
		if (errno == EINVAL) {
		close(fd);
		close(vss_fd);
		exit(EXIT_FAILURE);
		}
		else
		continue;
		}

		len = recvfrom(fd, vss_recv_buffer, vss_recv_buffer_len, 0,
		addr_p, &addr_l);
		len = read(vss_fd, vss_msg, sizeof(struct hv_vss_msg));

		if (len < 0) {
		syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s",
		addr.nl_pid, errno, strerror(errno));
		close(fd);
		return -1;
		}

		if (addr.nl_pid) {
		syslog(LOG_WARNING,
		"Received packet from untrusted pid:%u",
		addr.nl_pid);
		continue;
		if (len != sizeof(struct hv_vss_msg)) {
		syslog(LOG_ERR, "read failed; error:%d %s",
		errno, strerror(errno));
		close(vss_fd);
		return EXIT_FAILURE;
		}

		incoming_msg = (struct nlmsghdr *)vss_recv_buffer;

		if (incoming_msg->nlmsg_type != NLMSG_DONE)
		continue;

		incoming_cn_msg = (struct cn_msg *)NLMSG_DATA(incoming_msg);
		vss_msg = (struct hv_vss_msg *)incoming_cn_msg->data;
		op = vss_msg->vss_hdr.operation;
		error = HV_S_OK;

		@@ -331,12 +240,14 @@ int main(int argc, char *argv[])
		syslog(LOG_ERR, "Illegal op:%d\n", op);
		}
		vss_msg->error = error;
		len = netlink_send(fd, incoming_cn_msg);
		if (len < 0) {
		syslog(LOG_ERR, "net_link send failed; error:%d %s",
		errno, strerror(errno));
		len = write(vss_fd, &error, sizeof(struct hv_vss_msg));
		if (len != sizeof(struct hv_vss_msg)) {
		syslog(LOG_ERR, "write failed; error: %d %s", errno,
		strerror(errno));
		exit(EXIT_FAILURE);
		}
		}

		close(vss_fd);
		exit(0);
		}