1 files changed, 249 insertions, 0 deletions

diff --git a/tools/hv/hv_vss_daemon.c b/tools/hv/hv_vss_daemon.c
new file mode 100644
index 000000000000..fea03a3edaf4
--- /dev/null
+++ b/tools/hv/hv_vss_daemon.c
@@ -0,0 +1,249 @@
+/*
+ * An implementation of the host initiated guest snapshot for Hyper-V.
+ *
+ *
+ * Copyright (C) 2013, Microsoft, Inc.
+ * Author : K. Y. Srinivasan <kys@microsoft.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * 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, GOOD TITLE or
+ * NON INFRINGEMENT.  See the GNU General Public License for more
+ * details.
+ *
+ */
+
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/poll.h>
+#include <sys/ioctl.h>
+#include <linux/types.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <mntent.h>
+#include <stdlib.h>
+#include <unistd.h>
+#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>
+
+static char vss_recv_buffer[4096];
+static char vss_send_buffer[4096];
+static struct sockaddr_nl addr;
+
+#ifndef SOL_NETLINK
+#define SOL_NETLINK 270
+#endif
+
+
+static int vss_do_freeze(char *dir, unsigned int cmd, char *fs_op)
+{
+        int ret, fd = open(dir, O_RDONLY);
+
+        if (fd < 0)
+                return 1;
+        ret = ioctl(fd, cmd, 0);
+        syslog(LOG_INFO, "VSS: %s of %s: %s\n", fs_op, dir, strerror(errno));
+        close(fd);
+        return !!ret;
+}
+
+static int vss_operate(int operation)
+{
+        char *fs_op;
+        char match[] = "/dev/";
+        FILE *mounts;
+        struct mntent *ent;
+        unsigned int cmd;
+        int error = 0, root_seen = 0;
+
+        switch (operation) {
+        case VSS_OP_FREEZE:
+                cmd = FIFREEZE;
+                fs_op = "freeze";
+                break;
+        case VSS_OP_THAW:
+                cmd = FITHAW;
+                fs_op = "thaw";
+                break;
+        default:
+                return -1;
+        }
+
+        mounts = setmntent("/proc/mounts", "r");
+        if (mounts == NULL)
+                return -1;
+
+        while ((ent = getmntent(mounts))) {
+                if (strncmp(ent->mnt_fsname, match, strlen(match)))
+                        continue;
+                if (strcmp(ent->mnt_type, "iso9660") == 0)
+                        continue;
+                if (strcmp(ent->mnt_dir, "/") == 0) {
+                        root_seen = 1;
+                        continue;
+                }
+                error |= vss_do_freeze(ent->mnt_dir, cmd, fs_op);
+        }
+        endmntent(mounts);
+
+        if (root_seen) {
+                error |= vss_do_freeze("/", cmd, fs_op);
+        }
+
+        return error;
+}
+
+static int netlink_send(int fd, struct cn_msg *msg)
+{
+        struct nlmsghdr *nlh;
+        unsigned int size;
+        struct msghdr message;
+        char buffer[64];
+        struct iovec iov[2];
+
+        size = NLMSG_SPACE(sizeof(struct cn_msg) + msg->len);
+
+        nlh = (struct nlmsghdr *)buffer;
+        nlh->nlmsg_seq = 0;
+        nlh->nlmsg_pid = getpid();
+        nlh->nlmsg_type = NLMSG_DONE;
+        nlh->nlmsg_len = NLMSG_LENGTH(size - sizeof(*nlh));
+        nlh->nlmsg_flags = 0;
+
+        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);
+}
+
+int main(void)
+{
+        int fd, len, nl_group;
+        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;
+
+        if (daemon(1, 0))
+                return 1;
+
+        openlog("Hyper-V VSS", 0, LOG_USER);
+        syslog(LOG_INFO, "VSS starting; pid is:%d", getpid());
+
+        fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
+        if (fd < 0) {
+                syslog(LOG_ERR, "netlink socket creation failed; error:%d", fd);
+                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", error);
+                close(fd);
+                exit(EXIT_FAILURE);
+        }
+        nl_group = CN_VSS_IDX;
+        setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &nl_group, sizeof(nl_group));
+        /*
+         * Register ourselves with the kernel.
+         */
+        message = (struct cn_msg *)vss_send_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);
+
+        len = netlink_send(fd, message);
+        if (len < 0) {
+                syslog(LOG_ERR, "netlink_send failed; error:%d", len);
+                close(fd);
+                exit(EXIT_FAILURE);
+        }
+
+        pfd.fd = fd;
+
+        while (1) {
+                struct sockaddr *addr_p = (struct sockaddr *) &addr;
+                socklen_t addr_l = sizeof(addr);
+                pfd.events = POLLIN;
+                pfd.revents = 0;
+                poll(&pfd, 1, -1);
+
+                len = recvfrom(fd, vss_recv_buffer, sizeof(vss_recv_buffer), 0,
+                                addr_p, &addr_l);
+
+                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;
+                }
+
+                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;
+
+                switch (op) {
+                case VSS_OP_FREEZE:
+                case VSS_OP_THAW:
+                        error = vss_operate(op);
+                        if (error)
+                                error = HV_E_FAIL;
+                        break;
+                default:
+                        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", len);
+                        exit(EXIT_FAILURE);
+                }
+        }
+
+}