Tools: hv: vss: use misc char device to communicate with kernel

Use /dev/vmbus/hv_vss instead of netlink.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Tested-by: Alex Ng <alexng@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/tools/hv/hv_vss_daemon.c b/tools/hv/hv_vss_daemon.c
index 506dd01488286f8033f3ceaf3915fd06742f33de..36f18211afa7a1e18bee2fb757ce636fc6866936 100644 (file)
--- a/tools/hv/hv_vss_daemon.c
+++ b/tools/hv/hv_vss_daemon.c
@@ -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 @@ out:
        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",
-                               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);
+       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);
        }
        /*
         * 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;
-
-       message->len = sizeof(struct hv_vss_msg);
+       vss_msg->vss_hdr.operation = VSS_OP_REGISTER1;
 
-       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);
 }