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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /tools/hv/hv_vss_daemon.c
Initial import
Diffstat (limited to 'tools/hv/hv_vss_daemon.c')
-rw-r--r--tools/hv/hv_vss_daemon.c342
1 files changed, 342 insertions, 0 deletions
diff --git a/tools/hv/hv_vss_daemon.c b/tools/hv/hv_vss_daemon.c
new file mode 100644
index 000000000..506dd0148
--- /dev/null
+++ b/tools/hv/hv_vss_daemon.c
@@ -0,0 +1,342 @@
+/*
+ * 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 <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>
+#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)
+{
+ int ret, fd = open(dir, O_RDONLY);
+
+ if (fd < 0)
+ return 1;
+
+ ret = ioctl(fd, cmd, 0);
+
+ /*
+ * If a partition is mounted more than once, only the first
+ * FREEZE/THAW can succeed and the later ones will get
+ * EBUSY/EINVAL respectively: there could be 2 cases:
+ * 1) a user may mount the same partition to differnt directories
+ * by mistake or on purpose;
+ * 2) The subvolume of btrfs appears to have the same partition
+ * mounted more than once.
+ */
+ if (ret) {
+ if ((cmd == FIFREEZE && errno == EBUSY) ||
+ (cmd == FITHAW && errno == EINVAL)) {
+ close(fd);
+ return 0;
+ }
+ }
+
+ close(fd);
+ return !!ret;
+}
+
+static int vss_operate(int operation)
+{
+ char match[] = "/dev/";
+ FILE *mounts;
+ struct mntent *ent;
+ char errdir[1024] = {0};
+ unsigned int cmd;
+ int error = 0, root_seen = 0, save_errno = 0;
+
+ switch (operation) {
+ case VSS_OP_FREEZE:
+ cmd = FIFREEZE;
+ break;
+ case VSS_OP_THAW:
+ cmd = FITHAW;
+ 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 (hasmntopt(ent, MNTOPT_RO) != NULL)
+ continue;
+ if (strcmp(ent->mnt_type, "vfat") == 0)
+ continue;
+ if (strcmp(ent->mnt_dir, "/") == 0) {
+ root_seen = 1;
+ continue;
+ }
+ error |= vss_do_freeze(ent->mnt_dir, cmd);
+ if (error && operation == VSS_OP_FREEZE)
+ goto err;
+ }
+
+ endmntent(mounts);
+
+ if (root_seen) {
+ error |= vss_do_freeze("/", cmd);
+ if (error && operation == VSS_OP_FREEZE)
+ goto err;
+ }
+
+ goto out;
+err:
+ save_errno = errno;
+ if (ent) {
+ strncpy(errdir, ent->mnt_dir, sizeof(errdir)-1);
+ endmntent(mounts);
+ }
+ vss_operate(VSS_OP_THAW);
+ /* Call syslog after we thaw all filesystems */
+ if (ent)
+ syslog(LOG_ERR, "FREEZE of %s failed; error:%d %s",
+ errdir, save_errno, strerror(save_errno));
+ else
+ syslog(LOG_ERR, "FREEZE of / failed; error:%d %s", save_errno,
+ strerror(save_errno));
+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"
+ "Options are:\n"
+ " -n, --no-daemon stay in foreground, don't daemonize\n"
+ " -h, --help print this help\n", argv[0]);
+}
+
+int main(int argc, char *argv[])
+{
+ 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;
+ char *vss_recv_buffer;
+ size_t vss_recv_buffer_len;
+ int daemonize = 1, long_index = 0, opt;
+
+ static struct option long_options[] = {
+ {"help", no_argument, 0, 'h' },
+ {"no-daemon", no_argument, 0, 'n' },
+ {0, 0, 0, 0 }
+ };
+
+ while ((opt = getopt_long(argc, argv, "hn", long_options,
+ &long_index)) != -1) {
+ switch (opt) {
+ case 'n':
+ daemonize = 0;
+ break;
+ case 'h':
+ default:
+ print_usage(argv);
+ exit(EXIT_FAILURE);
+ }
+ }
+
+ if (daemonize && daemon(1, 0))
+ return 1;
+
+ 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);
+ 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);
+
+ len = netlink_send(fd, message);
+ if (len < 0) {
+ syslog(LOG_ERR, "netlink_send failed; error:%d %s", errno, strerror(errno));
+ 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;
+
+ if (poll(&pfd, 1, -1) < 0) {
+ syslog(LOG_ERR, "poll failed; error:%d %s", errno, strerror(errno));
+ if (errno == EINVAL) {
+ close(fd);
+ exit(EXIT_FAILURE);
+ }
+ else
+ continue;
+ }
+
+ len = recvfrom(fd, vss_recv_buffer, vss_recv_buffer_len, 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);
+ syslog(LOG_INFO, "VSS: op=%s: %s\n",
+ op == VSS_OP_FREEZE ? "FREEZE" : "THAW",
+ error ? "failed" : "succeeded");
+
+ if (error) {
+ error = HV_E_FAIL;
+ syslog(LOG_ERR, "op=%d failed!", op);
+ syslog(LOG_ERR, "report it with these files:");
+ syslog(LOG_ERR, "/etc/fstab and /proc/mounts");
+ }
+ 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 %s",
+ errno, strerror(errno));
+ exit(EXIT_FAILURE);
+ }
+ }
+
+}