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; }
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; char *vss_send_buffer; char *vss_recv_buffer; size_t vss_recv_buffer_len; if (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_HDRLEN + sizeof(struct cn_msg) + sizeof(struct hv_vss_msg); vss_send_buffer = calloc(1, vss_recv_buffer_len); vss_recv_buffer = calloc(1, vss_recv_buffer_len); if (!(vss_send_buffer && 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_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 %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); 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 %s", errno, strerror(errno)); exit(EXIT_FAILURE); } } }
int main(int argc, char *argv[]) { int vss_fd, len; int error; struct pollfd pfd; int op; struct hv_vss_msg vss_msg[1]; int daemonize = 1, long_index = 0, opt; int in_handshake = 1; __u32 kernel_modver; 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_fd = open("/dev/hv_vss", O_RDWR); if (vss_fd < 0) { syslog(LOG_ERR, "open /dev/hv_vss failed; error: %d %s", errno, strerror(errno)); exit(EXIT_FAILURE); } /* * Register ourselves with the kernel. */ vss_msg->vss_hdr.operation = VSS_OP_REGISTER1; len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg)); if (len < 0) { syslog(LOG_ERR, "registration to kernel failed; error: %d %s", errno, strerror(errno)); close(vss_fd); exit(EXIT_FAILURE); } pfd.fd = vss_fd; while (1) { 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(vss_fd); exit(EXIT_FAILURE); } else continue; } len = read(vss_fd, vss_msg, sizeof(struct hv_vss_msg)); if (in_handshake) { if (len != sizeof(kernel_modver)) { syslog(LOG_ERR, "invalid version negotiation"); exit(EXIT_FAILURE); } kernel_modver = *(__u32 *)vss_msg; in_handshake = 0; syslog(LOG_INFO, "VSS: kernel module version: %d", kernel_modver); 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; } 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 = 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); }