--- zzzz-none-000/linux-3.10.107/tools/hv/hv_vss_daemon.c 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/tools/hv/hv_vss_daemon.c 2021-02-04 17:41:59.000000000 +0000 @@ -19,10 +19,8 @@ #include -#include #include #include -#include #include #include #include @@ -31,51 +29,57 @@ #include #include #include -#include #include -#include #include -#include #include +#include -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) +/* 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); - syslog(LOG_INFO, "VSS: %s of %s: %s\n", fs_op, dir, strerror(errno)); + + /* + * 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 *fs_op; char match[] = "/dev/"; FILE *mounts; struct mntent *ent; + char errdir[1024] = {0}; unsigned int cmd; - int error = 0, root_seen = 0; + int error = 0, root_seen = 0, save_errno = 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; @@ -88,143 +92,146 @@ while ((ent = getmntent(mounts))) { if (strncmp(ent->mnt_fsname, match, strlen(match))) continue; - if (strcmp(ent->mnt_type, "iso9660") == 0) + 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, fs_op); + 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, fs_op); - } - + 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) +void print_usage(char *argv[]) { - 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); + 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(void) +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; + 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 (daemon(1, 0)) + if (daemonize && 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); + 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); } - 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; + 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", len); - 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; - 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 (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; } - if (addr.nl_pid) { - syslog(LOG_WARNING, - "Received packet from untrusted pid:%u", - addr.nl_pid); + 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; } - incoming_msg = (struct nlmsghdr *)vss_recv_buffer; - - if (incoming_msg->nlmsg_type != NLMSG_DONE) - 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_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; @@ -232,18 +239,29 @@ case VSS_OP_FREEZE: case VSS_OP_THAW: error = vss_operate(op); - if (error) + 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", len); + len = write(vss_fd, vss_msg, 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); }