コード例 #1
0
ファイル: mount.c プロジェクト: AlickHill/Lantern
// NB: mp->xxx fields may be trashed on exit
static int nfsmount(struct mntent *mp, int vfsflags, char *filteropts)
{
	CLIENT *mclient;
	char *hostname;
	char *pathname;
	char *mounthost;
	struct nfs_mount_data data;
	char *opt;
	struct hostent *hp;
	struct sockaddr_in server_addr;
	struct sockaddr_in mount_server_addr;
	int msock, fsock;
	union {
		struct fhstatus nfsv2;
		struct mountres3 nfsv3;
	} status;
	int daemonized;
	char *s;
	int port;
	int mountport;
	int proto;
	int bg;
	int soft;
	int intr;
	int posix;
	int nocto;
	int noac;
	int nolock;
	int retry;
	int tcp;
	int mountprog;
	int mountvers;
	int nfsprog;
	int nfsvers;
	int retval;

	find_kernel_nfs_mount_version();

	daemonized = 0;
	mounthost = NULL;
	retval = ETIMEDOUT;
	msock = fsock = -1;
	mclient = NULL;

	/* NB: hostname, mounthost, filteropts must be free()d prior to return */

	filteropts = xstrdup(filteropts); /* going to trash it later... */

	hostname = xstrdup(mp->mnt_fsname);
	/* mount_main() guarantees that ':' is there */
	s = strchr(hostname, ':');
	pathname = s + 1;
	*s = '\0';
	/* Ignore all but first hostname in replicated mounts
	   until they can be fully supported. ([email protected]) */
	s = strchr(hostname, ',');
	if (s) {
		*s = '\0';
		bb_error_msg("warning: multiple hostnames not supported");
	}

	server_addr.sin_family = AF_INET;
	if (!inet_aton(hostname, &server_addr.sin_addr)) {
		hp = gethostbyname(hostname);
		if (hp == NULL) {
			bb_herror_msg("%s", hostname);
			goto fail;
		}
		if (hp->h_length > sizeof(struct in_addr)) {
			bb_error_msg("got bad hp->h_length");
			hp->h_length = sizeof(struct in_addr);
		}
		memcpy(&server_addr.sin_addr,
				hp->h_addr, hp->h_length);
	}

	memcpy(&mount_server_addr, &server_addr, sizeof(mount_server_addr));

	/* add IP address to mtab options for use when unmounting */

	if (!mp->mnt_opts) { /* TODO: actually mp->mnt_opts is never NULL */
		mp->mnt_opts = xasprintf("addr=%s", inet_ntoa(server_addr.sin_addr));
	} else {
		char *tmp = xasprintf("%s%saddr=%s", mp->mnt_opts,
					mp->mnt_opts[0] ? "," : "",
					inet_ntoa(server_addr.sin_addr));
		free(mp->mnt_opts);
		mp->mnt_opts = tmp;
	}

	/* Set default options.
	 * rsize/wsize (and bsize, for ver >= 3) are left 0 in order to
	 * let the kernel decide.
	 * timeo is filled in after we know whether it'll be TCP or UDP. */
	memset(&data, 0, sizeof(data));
	data.retrans	= 3;
	data.acregmin	= 3;
	data.acregmax	= 60;
	data.acdirmin	= 30;
	data.acdirmax	= 60;
	data.namlen	= NAME_MAX;

	bg = 0;
	soft = 0;
	intr = 0;
	posix = 0;
	nocto = 0;
	nolock = 0;
	noac = 0;
	retry = 10000;		/* 10000 minutes ~ 1 week */
	tcp = 0;

	mountprog = MOUNTPROG;
	mountvers = 0;
	port = 0;
	mountport = 0;
	nfsprog = 100003;
	nfsvers = 0;

	/* parse options */
	if (filteropts)	for (opt = strtok(filteropts, ","); opt; opt = strtok(NULL, ",")) {
		char *opteq = strchr(opt, '=');
		if (opteq) {
			static const char *const options[] = {
				/* 0 */ "rsize",
				/* 1 */ "wsize",
				/* 2 */ "timeo",
				/* 3 */ "retrans",
				/* 4 */ "acregmin",
				/* 5 */ "acregmax",
				/* 6 */ "acdirmin",
				/* 7 */ "acdirmax",
				/* 8 */ "actimeo",
				/* 9 */ "retry",
				/* 10 */ "port",
				/* 11 */ "mountport",
				/* 12 */ "mounthost",
				/* 13 */ "mountprog",
				/* 14 */ "mountvers",
				/* 15 */ "nfsprog",
				/* 16 */ "nfsvers",
				/* 17 */ "vers",
				/* 18 */ "proto",
				/* 19 */ "namlen",
				/* 20 */ "addr",
				NULL
			};
			int val = xatoi_u(opteq + 1);
			*opteq = '\0';
			switch (index_in_str_array(options, opt)) {
			case 0: // "rsize"
				data.rsize = val;
				break;
			case 1: // "wsize"
				data.wsize = val;
				break;
			case 2: // "timeo"
				data.timeo = val;
				break;
			case 3: // "retrans"
				data.retrans = val;
				break;
			case 4: // "acregmin"
				data.acregmin = val;
				break;
			case 5: // "acregmax"
				data.acregmax = val;
				break;
			case 6: // "acdirmin"
				data.acdirmin = val;
				break;
			case 7: // "acdirmax"
				data.acdirmax = val;
				break;
			case 8: // "actimeo"
				data.acregmin = val;
				data.acregmax = val;
				data.acdirmin = val;
				data.acdirmax = val;
				break;
			case 9: // "retry"
				retry = val;
				break;
			case 10: // "port"
				port = val;
				break;
			case 11: // "mountport"
				mountport = val;
				break;
			case 12: // "mounthost"
				mounthost = xstrndup(opteq+1,
						strcspn(opteq+1," \t\n\r,"));
				break;
			case 13: // "mountprog"
				mountprog = val;
				break;
			case 14: // "mountvers"
				mountvers = val;
				break;
			case 15: // "nfsprog"
				nfsprog = val;
				break;
			case 16: // "nfsvers"
			case 17: // "vers"
				nfsvers = val;
				break;
			case 18: // "proto"
				if (!strncmp(opteq+1, "tcp", 3))
					tcp = 1;
				else if (!strncmp(opteq+1, "udp", 3))
					tcp = 0;
				else
					bb_error_msg("warning: unrecognized proto= option");
				break;
			case 19: // "namlen"
				if (nfs_mount_version >= 2)
					data.namlen = val;
				else
					bb_error_msg("warning: option namlen is not supported\n");
				break;
			case 20: // "addr" - ignore
				break;
			default:
				bb_error_msg("unknown nfs mount parameter: %s=%d", opt, val);
				goto fail;
			}
		}
		else {
			static const char *const options[] = {
				"bg",
				"fg",
				"soft",
				"hard",
				"intr",
				"posix",
				"cto",
				"ac",
				"tcp",
				"udp",
				"lock",
				NULL
			};
			int val = 1;
			if (!strncmp(opt, "no", 2)) {
				val = 0;
				opt += 2;
			}
			switch (index_in_str_array(options, opt)) {
			case 0: // "bg"
				bg = val;
				break;
			case 1: // "fg"
				bg = !val;
				break;
			case 2: // "soft"
				soft = val;
				break;
			case 3: // "hard"
				soft = !val;
				break;
			case 4: // "intr"
				intr = val;
				break;
			case 5: // "posix"
				posix = val;
				break;
			case 6: // "cto"
				nocto = !val;
				break;
			case 7: // "ac"
				noac = !val;
				break;
			case 8: // "tcp"
				tcp = val;
				break;
			case 9: // "udp"
				tcp = !val;
				break;
			case 10: // "lock"
				if (nfs_mount_version >= 3)
					nolock = !val;
				else
					bb_error_msg("warning: option nolock is not supported");
				break;
			default:
				bb_error_msg("unknown nfs mount option: %s%s", val ? "" : "no", opt);
				goto fail;
			}
		}
	}
	proto = (tcp) ? IPPROTO_TCP : IPPROTO_UDP;

	data.flags = (soft ? NFS_MOUNT_SOFT : 0)
		| (intr ? NFS_MOUNT_INTR : 0)
		| (posix ? NFS_MOUNT_POSIX : 0)
		| (nocto ? NFS_MOUNT_NOCTO : 0)
		| (noac ? NFS_MOUNT_NOAC : 0);
	if (nfs_mount_version >= 2)
		data.flags |= (tcp ? NFS_MOUNT_TCP : 0);
	if (nfs_mount_version >= 3)
		data.flags |= (nolock ? NFS_MOUNT_NONLM : 0);
	if (nfsvers > MAX_NFSPROT || mountvers > MAX_NFSPROT) {
		bb_error_msg("NFSv%d not supported", nfsvers);
		goto fail;
	}
	if (nfsvers && !mountvers)
		mountvers = (nfsvers < 3) ? 1 : nfsvers;
	if (nfsvers && nfsvers < mountvers) {
		mountvers = nfsvers;
	}

	/* Adjust options if none specified */
	if (!data.timeo)
		data.timeo = tcp ? 70 : 7;

	data.version = nfs_mount_version;

	if (vfsflags & MS_REMOUNT)
		goto do_mount;

	/*
	 * If the previous mount operation on the same host was
	 * backgrounded, and the "bg" for this mount is also set,
	 * give up immediately, to avoid the initial timeout.
	 */
	if (bg && we_saw_this_host_before(hostname)) {
		daemonized = daemonize(); /* parent or error */
		if (daemonized <= 0) { /* parent or error */
			retval = -daemonized;
			goto ret;
		}
	}

	/* create mount daemon client */
	/* See if the nfs host = mount host. */
	if (mounthost) {
		if (mounthost[0] >= '0' && mounthost[0] <= '9') {
			mount_server_addr.sin_family = AF_INET;
			mount_server_addr.sin_addr.s_addr = inet_addr(hostname);
		} else {
			hp = gethostbyname(mounthost);
			if (hp == NULL) {
				bb_herror_msg("%s", mounthost);
				goto fail;
			} else {
				if (hp->h_length > sizeof(struct in_addr)) {
					bb_error_msg("got bad hp->h_length?");
					hp->h_length = sizeof(struct in_addr);
				}
				mount_server_addr.sin_family = AF_INET;
				memcpy(&mount_server_addr.sin_addr,
						hp->h_addr, hp->h_length);
			}
		}
	}

	/*
	 * The following loop implements the mount retries. When the mount
	 * times out, and the "bg" option is set, we background ourself
	 * and continue trying.
	 *
	 * The case where the mount point is not present and the "bg"
	 * option is set, is treated as a timeout. This is done to
	 * support nested mounts.
	 *
	 * The "retry" count specified by the user is the number of
	 * minutes to retry before giving up.
	 */
	{
		struct timeval total_timeout;
		struct timeval retry_timeout;
		struct pmap* pm_mnt;
		time_t t;
		time_t prevt;
		time_t timeout;

		retry_timeout.tv_sec = 3;
		retry_timeout.tv_usec = 0;
		total_timeout.tv_sec = 20;
		total_timeout.tv_usec = 0;
		timeout = time(NULL) + 60 * retry;
		prevt = 0;
		t = 30;
retry:
		/* be careful not to use too many CPU cycles */
		if (t - prevt < 30)
			sleep(30);

		pm_mnt = get_mountport(&mount_server_addr,
				mountprog,
				mountvers,
				proto,
				mountport);
		nfsvers = (pm_mnt->pm_vers < 2) ? 2 : pm_mnt->pm_vers;

		/* contact the mount daemon via TCP */
		mount_server_addr.sin_port = htons(pm_mnt->pm_port);
		msock = RPC_ANYSOCK;

		switch (pm_mnt->pm_prot) {
		case IPPROTO_UDP:
			mclient = clntudp_create(&mount_server_addr,
						 pm_mnt->pm_prog,
						 pm_mnt->pm_vers,
						 retry_timeout,
						 &msock);
			if (mclient)
				break;
			mount_server_addr.sin_port = htons(pm_mnt->pm_port);
			msock = RPC_ANYSOCK;
		case IPPROTO_TCP:
			mclient = clnttcp_create(&mount_server_addr,
						 pm_mnt->pm_prog,
						 pm_mnt->pm_vers,
						 &msock, 0, 0);
			break;
		default:
			mclient = 0;
		}
		if (!mclient) {
			if (!daemonized && prevt == 0)
				error_msg_rpc(clnt_spcreateerror(" "));
		} else {
			enum clnt_stat clnt_stat;
			/* try to mount hostname:pathname */
			mclient->cl_auth = authunix_create_default();

			/* make pointers in xdr_mountres3 NULL so
			 * that xdr_array allocates memory for us
			 */
			memset(&status, 0, sizeof(status));

			if (pm_mnt->pm_vers == 3)
				clnt_stat = clnt_call(mclient, MOUNTPROC3_MNT,
					      (xdrproc_t) xdr_dirpath,
					      (caddr_t) &pathname,
					      (xdrproc_t) xdr_mountres3,
					      (caddr_t) &status,
					      total_timeout);
			else
				clnt_stat = clnt_call(mclient, MOUNTPROC_MNT,
					      (xdrproc_t) xdr_dirpath,
					      (caddr_t) &pathname,
					      (xdrproc_t) xdr_fhstatus,
					      (caddr_t) &status,
					      total_timeout);

			if (clnt_stat == RPC_SUCCESS)
				goto prepare_kernel_data; /* we're done */
			if (errno != ECONNREFUSED) {
				error_msg_rpc(clnt_sperror(mclient, " "));
				goto fail;	/* don't retry */
			}
			/* Connection refused */
			if (!daemonized && prevt == 0) /* print just once */
				error_msg_rpc(clnt_sperror(mclient, " "));
			auth_destroy(mclient->cl_auth);
			clnt_destroy(mclient);
			mclient = 0;
			close(msock);
		}

		/* Timeout. We are going to retry... maybe */

		if (!bg)
			goto fail;
		if (!daemonized) {
			daemonized = daemonize();
			if (daemonized <= 0) { /* parent or error */
				retval = -daemonized;
				goto ret;
			}
		}
		prevt = t;
		t = time(NULL);
		if (t >= timeout)
			/* TODO error message */
			goto fail;

		goto retry;
	}

prepare_kernel_data:

	if (nfsvers == 2) {
		if (status.nfsv2.fhs_status != 0) {
			bb_error_msg("%s:%s failed, reason given by server: %s",
				hostname, pathname,
				nfs_strerror(status.nfsv2.fhs_status));
			goto fail;
		}
		memcpy(data.root.data,
				(char *) status.nfsv2.fhstatus_u.fhs_fhandle,
				NFS_FHSIZE);
		data.root.size = NFS_FHSIZE;
		memcpy(data.old_root.data,
				(char *) status.nfsv2.fhstatus_u.fhs_fhandle,
				NFS_FHSIZE);
	} else {
		fhandle3 *my_fhandle;
		if (status.nfsv3.fhs_status != 0) {
			bb_error_msg("%s:%s failed, reason given by server: %s",
				hostname, pathname,
				nfs_strerror(status.nfsv3.fhs_status));
			goto fail;
		}
		my_fhandle = &status.nfsv3.mountres3_u.mountinfo.fhandle;
		memset(data.old_root.data, 0, NFS_FHSIZE);
		memset(&data.root, 0, sizeof(data.root));
		data.root.size = my_fhandle->fhandle3_len;
		memcpy(data.root.data,
				(char *) my_fhandle->fhandle3_val,
				my_fhandle->fhandle3_len);

		data.flags |= NFS_MOUNT_VER3;
	}

	/* create nfs socket for kernel */

	if (tcp) {
		if (nfs_mount_version < 3) {
			bb_error_msg("NFS over TCP is not supported");
			goto fail;
		}
		fsock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	} else
		fsock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if (fsock < 0) {
		bb_perror_msg("nfs socket");
		goto fail;
	}
	if (bindresvport(fsock, 0) < 0) {
		bb_perror_msg("nfs bindresvport");
		goto fail;
	}
	if (port == 0) {
		server_addr.sin_port = PMAPPORT;
		port = pmap_getport(&server_addr, nfsprog, nfsvers,
					tcp ? IPPROTO_TCP : IPPROTO_UDP);
		if (port == 0)
			port = NFS_PORT;
	}
	server_addr.sin_port = htons(port);

	/* prepare data structure for kernel */

	data.fd = fsock;
	memcpy((char *) &data.addr, (char *) &server_addr, sizeof(data.addr));
	strncpy(data.hostname, hostname, sizeof(data.hostname));

	/* clean up */

	auth_destroy(mclient->cl_auth);
	clnt_destroy(mclient);
	close(msock);

	if (bg) {
		/* We must wait until mount directory is available */
		struct stat statbuf;
		int delay = 1;
		while (stat(mp->mnt_dir, &statbuf) == -1) {
			if (!daemonized) {
				daemonized = daemonize();
				if (daemonized <= 0) { /* parent or error */
					retval = -daemonized;
					goto ret;
				}
			}
			sleep(delay);	/* 1, 2, 4, 8, 16, 30, ... */
			delay *= 2;
			if (delay > 30)
				delay = 30;
		}
	}

do_mount: /* perform actual mount */

	mp->mnt_type = (char*)"nfs";
	retval = mount_it_now(mp, vfsflags, (char*)&data);
	goto ret;

fail:	/* abort */

	if (msock != -1) {
		if (mclient) {
			auth_destroy(mclient->cl_auth);
			clnt_destroy(mclient);
		}
		close(msock);
	}
	if (fsock != -1)
		close(fsock);

ret:
	free(hostname);
	free(mounthost);
	free(filteropts);
	return retval;
}
コード例 #2
0
int nfsmount(const char *spec, const char *node, int *flags,
	     char **extra_opts, char **mount_opts, int running_bg)
{
	static char *prev_bg_host;
	char hostdir[1024];
	CLIENT *mclient;
	char *hostname;
	char *pathname;
	char *old_opts;
	char *mounthost=NULL;
	char new_opts[1024];
	struct timeval total_timeout;
	enum clnt_stat clnt_stat;
	static struct nfs_mount_data data;
	char *opt, *opteq;
	int val;
	struct hostent *hp;
	struct sockaddr_in server_addr;
	struct sockaddr_in mount_server_addr;
	struct pmap* pm_mnt;
	int msock, fsock;
	struct timeval retry_timeout;
	union {
		struct fhstatus nfsv2;
		struct mountres3 nfsv3;
	} status;
	struct stat statbuf;
	char *s;
	int port;
	int mountport;
	int proto;
	int bg;
	int soft;
	int intr;
	int posix;
	int nocto;
	int noac;
	int nolock;
	int retry;
	int tcp;
	int mountprog;
	int mountvers;
	int nfsprog;
	int nfsvers;
	int retval;
	time_t t;
	time_t prevt;
	time_t timeout;

	find_kernel_nfs_mount_version();

	retval = EX_FAIL;
	msock = fsock = -1;
	mclient = NULL;
	if (strlen(spec) >= sizeof(hostdir)) {
		bb_error_msg("excessively long host:dir argument");
		goto fail;
	}
	strcpy(hostdir, spec);
	if ((s = strchr(hostdir, ':'))) {
		hostname = hostdir;
		pathname = s + 1;
		*s = '\0';
		/* Ignore all but first hostname in replicated mounts
		   until they can be fully supported. ([email protected]) */
		if ((s = strchr(hostdir, ','))) {
			*s = '\0';
			bb_error_msg("warning: multiple hostnames not supported");
		}
	} else {
		bb_error_msg("directory to mount not in host:dir format");
		goto fail;
	}

	server_addr.sin_family = AF_INET;
#ifdef HAVE_inet_aton
	if (!inet_aton(hostname, &server_addr.sin_addr))
#endif
	{
		if ((hp = gethostbyname(hostname)) == NULL) {
			bb_herror_msg("%s", hostname);
			goto fail;
		} else {
			if (hp->h_length > sizeof(struct in_addr)) {
				bb_error_msg("got bad hp->h_length");
				hp->h_length = sizeof(struct in_addr);
			}
			memcpy(&server_addr.sin_addr,
			       hp->h_addr, hp->h_length);
		}
	}

	memcpy (&mount_server_addr, &server_addr, sizeof (mount_server_addr));

	/* add IP address to mtab options for use when unmounting */

	s = inet_ntoa(server_addr.sin_addr);
	old_opts = *extra_opts;
	if (!old_opts)
		old_opts = "";
	if (strlen(old_opts) + strlen(s) + 10 >= sizeof(new_opts)) {
		bb_error_msg("excessively long option argument");
		goto fail;
	}
	sprintf(new_opts, "%s%saddr=%s",
		old_opts, *old_opts ? "," : "", s);
	*extra_opts = bb_xstrdup(new_opts);

	/* Set default options.
	 * rsize/wsize (and bsize, for ver >= 3) are left 0 in order to
	 * let the kernel decide.
	 * timeo is filled in after we know whether it'll be TCP or UDP. */
	memset(&data, 0, sizeof(data));
	data.retrans	= 3;
	data.acregmin	= 3;
	data.acregmax	= 60;
	data.acdirmin	= 30;
	data.acdirmax	= 60;
#if NFS_MOUNT_VERSION >= 2
	data.namlen	= NAME_MAX;
#endif

	bg = 0;
	soft = 0;
	intr = 0;
	posix = 0;
	nocto = 0;
	nolock = 0;
	noac = 0;
	retry = 10000;		/* 10000 minutes ~ 1 week */
	tcp = 0;

	mountprog = MOUNTPROG;
	mountvers = 0;
	port = 0;
	mountport = 0;
	nfsprog = NFS_PROGRAM;
	nfsvers = 0;

	/* parse options */

	for (opt = strtok(old_opts, ","); opt; opt = strtok(NULL, ",")) {
		if ((opteq = strchr(opt, '='))) {
			val = atoi(opteq + 1);	
			*opteq = '\0';
			if (!strcmp(opt, "rsize"))
				data.rsize = val;
			else if (!strcmp(opt, "wsize"))
				data.wsize = val;
			else if (!strcmp(opt, "timeo"))
				data.timeo = val;
			else if (!strcmp(opt, "retrans"))
				data.retrans = val;
			else if (!strcmp(opt, "acregmin"))
				data.acregmin = val;
			else if (!strcmp(opt, "acregmax"))
				data.acregmax = val;
			else if (!strcmp(opt, "acdirmin"))
				data.acdirmin = val;
			else if (!strcmp(opt, "acdirmax"))
				data.acdirmax = val;
			else if (!strcmp(opt, "actimeo")) {
				data.acregmin = val;
				data.acregmax = val;
				data.acdirmin = val;
				data.acdirmax = val;
			}
			else if (!strcmp(opt, "retry"))
				retry = val;
			else if (!strcmp(opt, "port"))
				port = val;
			else if (!strcmp(opt, "mountport"))
			        mountport = val;
			else if (!strcmp(opt, "mounthost"))
			        mounthost=bb_xstrndup(opteq+1,
						  strcspn(opteq+1," \t\n\r,"));
			else if (!strcmp(opt, "mountprog"))
				mountprog = val;
			else if (!strcmp(opt, "mountvers"))
				mountvers = val;
			else if (!strcmp(opt, "nfsprog"))
				nfsprog = val;
			else if (!strcmp(opt, "nfsvers") ||
				 !strcmp(opt, "vers"))
				nfsvers = val;
			else if (!strcmp(opt, "proto")) {
				if (!strncmp(opteq+1, "tcp", 3))
					tcp = 1;
				else if (!strncmp(opteq+1, "udp", 3))
					tcp = 0;
				else
					printf(_("Warning: Unrecognized proto= option.\n"));
			} else if (!strcmp(opt, "namlen")) {
#if NFS_MOUNT_VERSION >= 2
				if (nfs_mount_version >= 2)
					data.namlen = val;
				else
#endif
				printf(_("Warning: Option namlen is not supported.\n"));
			} else if (!strcmp(opt, "addr"))
				/* ignore */;
			else {
				printf(_("unknown nfs mount parameter: "
				       "%s=%d\n"), opt, val);
				goto fail;
			}
		}
		else {
			val = 1;
			if (!strncmp(opt, "no", 2)) {
				val = 0;
				opt += 2;
			}
			if (!strcmp(opt, "bg")) 
				bg = val;
			else if (!strcmp(opt, "fg")) 
				bg = !val;
			else if (!strcmp(opt, "soft"))
				soft = val;
			else if (!strcmp(opt, "hard"))
				soft = !val;
			else if (!strcmp(opt, "intr"))
				intr = val;
			else if (!strcmp(opt, "posix"))
				posix = val;
			else if (!strcmp(opt, "cto"))
				nocto = !val;
			else if (!strcmp(opt, "ac"))
				noac = !val;
			else if (!strcmp(opt, "tcp"))
				tcp = val;
			else if (!strcmp(opt, "udp"))
				tcp = !val;
			else if (!strcmp(opt, "lock")) {
				if (nfs_mount_version >= 3)
					nolock = !val;
				else
					printf(_("Warning: option nolock is not supported.\n"));
			} else {
				printf(_("unknown nfs mount option: "
					   "%s%s\n"), val ? "" : "no", opt);
				goto fail;
			}
		}
	}
	proto = (tcp) ? IPPROTO_TCP : IPPROTO_UDP;

	data.flags = (soft ? NFS_MOUNT_SOFT : 0)
		| (intr ? NFS_MOUNT_INTR : 0)
		| (posix ? NFS_MOUNT_POSIX : 0)
		| (nocto ? NFS_MOUNT_NOCTO : 0)
		| (noac ? NFS_MOUNT_NOAC : 0);
#if NFS_MOUNT_VERSION >= 2
	if (nfs_mount_version >= 2)
		data.flags |= (tcp ? NFS_MOUNT_TCP : 0);
#endif
#if NFS_MOUNT_VERSION >= 3
	if (nfs_mount_version >= 3)
		data.flags |= (nolock ? NFS_MOUNT_NONLM : 0);
#endif
	if (nfsvers > MAX_NFSPROT) {
		bb_error_msg("NFSv%d not supported!", nfsvers);
		return 0;
	}
	if (mountvers > MAX_NFSPROT) {
		bb_error_msg("NFSv%d not supported!", nfsvers);
		return 0;
	}
	if (nfsvers && !mountvers)
		mountvers = (nfsvers < 3) ? 1 : nfsvers;
	if (nfsvers && nfsvers < mountvers) {
		mountvers = nfsvers;
	}

	/* Adjust options if none specified */
	if (!data.timeo)
		data.timeo = tcp ? 70 : 7;

#ifdef NFS_MOUNT_DEBUG
	printf("rsize = %d, wsize = %d, timeo = %d, retrans = %d\n",
		data.rsize, data.wsize, data.timeo, data.retrans);
	printf("acreg (min, max) = (%d, %d), acdir (min, max) = (%d, %d)\n",
		data.acregmin, data.acregmax, data.acdirmin, data.acdirmax);
	printf("port = %d, bg = %d, retry = %d, flags = %.8x\n",
		port, bg, retry, data.flags);
	printf("mountprog = %d, mountvers = %d, nfsprog = %d, nfsvers = %d\n",
		mountprog, mountvers, nfsprog, nfsvers);
	printf("soft = %d, intr = %d, posix = %d, nocto = %d, noac = %d\n",
		(data.flags & NFS_MOUNT_SOFT) != 0,
		(data.flags & NFS_MOUNT_INTR) != 0,
		(data.flags & NFS_MOUNT_POSIX) != 0,
		(data.flags & NFS_MOUNT_NOCTO) != 0,
		(data.flags & NFS_MOUNT_NOAC) != 0);
#if NFS_MOUNT_VERSION >= 2
	printf("tcp = %d\n",
		(data.flags & NFS_MOUNT_TCP) != 0);
#endif
#endif

	data.version = nfs_mount_version;
	*mount_opts = (char *) &data;

	if (*flags & MS_REMOUNT)
		return 0;

	/*
	 * If the previous mount operation on the same host was
	 * backgrounded, and the "bg" for this mount is also set,
	 * give up immediately, to avoid the initial timeout.
	 */
	if (bg && !running_bg &&
	    prev_bg_host && strcmp(hostname, prev_bg_host) == 0) {
		if (retry > 0)
			retval = EX_BG;
		return retval;
	}

	/* create mount deamon client */
	/* See if the nfs host = mount host. */
	if (mounthost) {
	  if (mounthost[0] >= '0' && mounthost[0] <= '9') {
	    mount_server_addr.sin_family = AF_INET;
	    mount_server_addr.sin_addr.s_addr = inet_addr(hostname);
	  } else {
		  if ((hp = gethostbyname(mounthost)) == NULL) {
			  bb_herror_msg("%s", mounthost);
			  goto fail;
		  } else {
			  if (hp->h_length > sizeof(struct in_addr)) {
				  bb_error_msg("got bad hp->h_length?");
				  hp->h_length = sizeof(struct in_addr);
			  }
			  mount_server_addr.sin_family = AF_INET;
			  memcpy(&mount_server_addr.sin_addr,
				 hp->h_addr, hp->h_length);
		  }
	  }
	}

	/*
	 * The following loop implements the mount retries. On the first
	 * call, "running_bg" is 0. When the mount times out, and the
	 * "bg" option is set, the exit status EX_BG will be returned.
	 * For a backgrounded mount, there will be a second call by the
	 * child process with "running_bg" set to 1.
	 *
	 * The case where the mount point is not present and the "bg"
	 * option is set, is treated as a timeout. This is done to
	 * support nested mounts.
	 *
	 * The "retry" count specified by the user is the number of
	 * minutes to retry before giving up.
	 *
	 * Only the first error message will be displayed.
	 */
	retry_timeout.tv_sec = 3;
	retry_timeout.tv_usec = 0;
	total_timeout.tv_sec = 20;
	total_timeout.tv_usec = 0;
	timeout = time(NULL) + 60 * retry;
	prevt = 0;
	t = 30;
	val = 1;
	for (;;) {
		if (bg && stat(node, &statbuf) == -1) {
			if (running_bg) {
				sleep(val);	/* 1, 2, 4, 8, 16, 30, ... */
				val *= 2;
				if (val > 30)
					val = 30;
			}
		} else {
			/* be careful not to use too many CPU cycles */
			if (t - prevt < 30)
				sleep(30);

			pm_mnt = get_mountport(&mount_server_addr,
				       mountprog,
				       mountvers,
				       proto,
 				       mountport);

			/* contact the mount daemon via TCP */
			mount_server_addr.sin_port = htons(pm_mnt->pm_port);
			msock = RPC_ANYSOCK;

			switch (pm_mnt->pm_prot) {
			case IPPROTO_UDP:
				mclient = clntudp_create(&mount_server_addr,
						 pm_mnt->pm_prog,
						 pm_mnt->pm_vers,
						 retry_timeout,
						 &msock);
		  if (mclient)
			  break;
		  mount_server_addr.sin_port = htons(pm_mnt->pm_port);
		  msock = RPC_ANYSOCK;
		case IPPROTO_TCP:
			mclient = clnttcp_create(&mount_server_addr,
						 pm_mnt->pm_prog,
						 pm_mnt->pm_vers,
						 &msock, 0, 0);
			break;
		default:
			mclient = 0;
			}
			if (mclient) {
				/* try to mount hostname:pathname */
				mclient->cl_auth = authunix_create_default();

			/* make pointers in xdr_mountres3 NULL so
			 * that xdr_array allocates memory for us
			 */
			memset(&status, 0, sizeof(status));

			if (pm_mnt->pm_vers == 3)
				clnt_stat = clnt_call(mclient, MOUNTPROC3_MNT,
						      (xdrproc_t) xdr_dirpath,
						      (caddr_t) &pathname,
						      (xdrproc_t) xdr_mountres3,
						      (caddr_t) &status,
					total_timeout);
			else
				clnt_stat = clnt_call(mclient, MOUNTPROC_MNT,
						      (xdrproc_t) xdr_dirpath,
						      (caddr_t) &pathname,
						      (xdrproc_t) xdr_fhstatus,
						      (caddr_t) &status,
						      total_timeout);

				if (clnt_stat == RPC_SUCCESS)
					break;		/* we're done */
				if (errno != ECONNREFUSED) {
					clnt_perror(mclient, "mount");
					goto fail;	/* don't retry */
				}
				if (!running_bg && prevt == 0)
					clnt_perror(mclient, "mount");
				auth_destroy(mclient->cl_auth);
				clnt_destroy(mclient);
				mclient = 0;
				close(msock);
			} else {
				if (!running_bg && prevt == 0)
					clnt_pcreateerror("mount");
			}
			prevt = t;
		}
		if (!bg)
		        goto fail;
		if (!running_bg) {
			prev_bg_host = bb_xstrdup(hostname);
			if (retry > 0)
				retval = EX_BG;
			goto fail;
		}
		t = time(NULL);
		if (t >= timeout)
			goto fail;
	}
	nfsvers = (pm_mnt->pm_vers < 2) ? 2 : pm_mnt->pm_vers;

	if (nfsvers == 2) {
		if (status.nfsv2.fhs_status != 0) {
			bb_error_msg("%s:%s failed, reason given by server: %s",
				hostname, pathname,
				nfs_strerror(status.nfsv2.fhs_status));
			goto fail;
		}
		memcpy(data.root.data,
		       (char *) status.nfsv2.fhstatus_u.fhs_fhandle,
		       NFS_FHSIZE);
#if NFS_MOUNT_VERSION >= 4
		data.root.size = NFS_FHSIZE;
		memcpy(data.old_root.data,
		       (char *) status.nfsv2.fhstatus_u.fhs_fhandle,
		       NFS_FHSIZE);
#endif
	} else {
#if NFS_MOUNT_VERSION >= 4
		fhandle3 *my_fhandle;
		if (status.nfsv3.fhs_status != 0) {
			bb_error_msg("%s:%s failed, reason given by server: %s",
				hostname, pathname,
				nfs_strerror(status.nfsv3.fhs_status));
			goto fail;
		}
		my_fhandle = &status.nfsv3.mountres3_u.mountinfo.fhandle;
		memset(data.old_root.data, 0, NFS_FHSIZE);
		memset(&data.root, 0, sizeof(data.root));
		data.root.size = my_fhandle->fhandle3_len;
		memcpy(data.root.data,
		       (char *) my_fhandle->fhandle3_val,
		       my_fhandle->fhandle3_len);

		data.flags |= NFS_MOUNT_VER3;
#endif
	}

	/* create nfs socket for kernel */

	if (tcp) {
		if (nfs_mount_version < 3) {
	     		printf(_("NFS over TCP is not supported.\n"));
			goto fail;
		}
		fsock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	} else
		fsock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if (fsock < 0) {
		perror(_("nfs socket"));
		goto fail;
	}
	if (bindresvport(fsock, 0) < 0) {
		perror(_("nfs bindresvport"));
		goto fail;
	}
	if (port == 0) {
		server_addr.sin_port = PMAPPORT;
		port = pmap_getport(&server_addr, nfsprog, nfsvers,
			tcp ? IPPROTO_TCP : IPPROTO_UDP);
		if (port == 0)
			port = NFS_PORT;
#ifdef NFS_MOUNT_DEBUG
		else
			printf(_("used portmapper to find NFS port\n"));
#endif
	}
#ifdef NFS_MOUNT_DEBUG
	printf(_("using port %d for nfs deamon\n"), port);
#endif
	server_addr.sin_port = htons(port);
	 /*
	  * connect() the socket for kernels 1.3.10 and below only,
	  * to avoid problems with multihomed hosts.
	  * --Swen
	  */
	if (get_kernel_revision() <= 66314
	    && connect(fsock, (struct sockaddr *) &server_addr,
		       sizeof (server_addr)) < 0) {
		perror(_("nfs connect"));
		goto fail;
	}

	/* prepare data structure for kernel */

	data.fd = fsock;
	memcpy((char *) &data.addr, (char *) &server_addr, sizeof(data.addr));
	strncpy(data.hostname, hostname, sizeof(data.hostname));

	/* clean up */

	auth_destroy(mclient->cl_auth);
	clnt_destroy(mclient);
	close(msock);
	return 0;

	/* abort */

fail:
	if (msock != -1) {
		if (mclient) {
			auth_destroy(mclient->cl_auth);
			clnt_destroy(mclient);
		}
		close(msock);
	}
	if (fsock != -1)
		close(fsock);
	return retval;
}