xref: /openbmc/linux/fs/nfs/nfsroot.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
1 /*
2  *  $Id: nfsroot.c,v 1.45 1998/03/07 10:44:46 mj Exp $
3  *
4  *  Copyright (C) 1995, 1996  Gero Kuhlmann <gero@gkminix.han.de>
5  *
6  *  Allow an NFS filesystem to be mounted as root. The way this works is:
7  *     (1) Use the IP autoconfig mechanism to set local IP addresses and routes.
8  *     (2) Handle RPC negotiation with the system which replied to RARP or
9  *         was reported as a boot server by BOOTP or manually.
10  *     (3) The actual mounting is done later, when init() is running.
11  *
12  *
13  *	Changes:
14  *
15  *	Alan Cox	:	Removed get_address name clash with FPU.
16  *	Alan Cox	:	Reformatted a bit.
17  *	Gero Kuhlmann	:	Code cleanup
18  *	Michael Rausch  :	Fixed recognition of an incoming RARP answer.
19  *	Martin Mares	: (2.0)	Auto-configuration via BOOTP supported.
20  *	Martin Mares	:	Manual selection of interface & BOOTP/RARP.
21  *	Martin Mares	:	Using network routes instead of host routes,
22  *				allowing the default configuration to be used
23  *				for normal operation of the host.
24  *	Martin Mares	:	Randomized timer with exponential backoff
25  *				installed to minimize network congestion.
26  *	Martin Mares	:	Code cleanup.
27  *	Martin Mares	: (2.1)	BOOTP and RARP made configuration options.
28  *	Martin Mares	:	Server hostname generation fixed.
29  *	Gerd Knorr	:	Fixed wired inode handling
30  *	Martin Mares	: (2.2)	"0.0.0.0" addresses from command line ignored.
31  *	Martin Mares	:	RARP replies not tested for server address.
32  *	Gero Kuhlmann	: (2.3) Some bug fixes and code cleanup again (please
33  *				send me your new patches _before_ bothering
34  *				Linus so that I don' always have to cleanup
35  *				_afterwards_ - thanks)
36  *	Gero Kuhlmann	:	Last changes of Martin Mares undone.
37  *	Gero Kuhlmann	: 	RARP replies are tested for specified server
38  *				again. However, it's now possible to have
39  *				different RARP and NFS servers.
40  *	Gero Kuhlmann	:	"0.0.0.0" addresses from command line are
41  *				now mapped to INADDR_NONE.
42  *	Gero Kuhlmann	:	Fixed a bug which prevented BOOTP path name
43  *				from being used (thanks to Leo Spiekman)
44  *	Andy Walker	:	Allow to specify the NFS server in nfs_root
45  *				without giving a path name
46  *	Swen Th�mmler	:	Allow to specify the NFS options in nfs_root
47  *				without giving a path name. Fix BOOTP request
48  *				for domainname (domainname is NIS domain, not
49  *				DNS domain!). Skip dummy devices for BOOTP.
50  *	Jacek Zapala	:	Fixed a bug which prevented server-ip address
51  *				from nfsroot parameter from being used.
52  *	Olaf Kirch	:	Adapted to new NFS code.
53  *	Jakub Jelinek	:	Free used code segment.
54  *	Marko Kohtala	:	Fixed some bugs.
55  *	Martin Mares	:	Debug message cleanup
56  *	Martin Mares	:	Changed to use the new generic IP layer autoconfig
57  *				code. BOOTP and RARP moved there.
58  *	Martin Mares	:	Default path now contains host name instead of
59  *				host IP address (but host name defaults to IP
60  *				address anyway).
61  *	Martin Mares	:	Use root_server_addr appropriately during setup.
62  *	Martin Mares	:	Rewrote parameter parsing, now hopefully giving
63  *				correct overriding.
64  *	Trond Myklebust :	Add in preliminary support for NFSv3 and TCP.
65  *				Fix bug in root_nfs_addr(). nfs_data.namlen
66  *				is NOT for the length of the hostname.
67  *	Hua Qin		:	Support for mounting root file system via
68  *				NFS over TCP.
69  *	Fabian Frederick:	Option parser rebuilt (using parser lib)
70 */
71 
72 #include <linux/types.h>
73 #include <linux/string.h>
74 #include <linux/kernel.h>
75 #include <linux/time.h>
76 #include <linux/fs.h>
77 #include <linux/init.h>
78 #include <linux/sunrpc/clnt.h>
79 #include <linux/nfs.h>
80 #include <linux/nfs_fs.h>
81 #include <linux/nfs_mount.h>
82 #include <linux/in.h>
83 #include <linux/major.h>
84 #include <linux/utsname.h>
85 #include <linux/inet.h>
86 #include <linux/root_dev.h>
87 #include <net/ipconfig.h>
88 #include <linux/parser.h>
89 
90 /* Define this to allow debugging output */
91 #undef NFSROOT_DEBUG
92 #define NFSDBG_FACILITY NFSDBG_ROOT
93 
94 /* Default path we try to mount. "%s" gets replaced by our IP address */
95 #define NFS_ROOT		"/tftpboot/%s"
96 
97 /* Parameters passed from the kernel command line */
98 static char nfs_root_name[256] __initdata = "";
99 
100 /* Address of NFS server */
101 static __be32 servaddr __initdata = 0;
102 
103 /* Name of directory to mount */
104 static char nfs_path[NFS_MAXPATHLEN] __initdata = { 0, };
105 
106 /* NFS-related data */
107 static struct nfs_mount_data nfs_data __initdata = { 0, };/* NFS mount info */
108 static int nfs_port __initdata = 0;		/* Port to connect to for NFS */
109 static int mount_port __initdata = 0;		/* Mount daemon port number */
110 
111 
112 /***************************************************************************
113 
114 			     Parsing of options
115 
116  ***************************************************************************/
117 
118 enum {
119 	/* Options that take integer arguments */
120 	Opt_port, Opt_rsize, Opt_wsize, Opt_timeo, Opt_retrans, Opt_acregmin,
121 	Opt_acregmax, Opt_acdirmin, Opt_acdirmax,
122 	/* Options that take no arguments */
123 	Opt_soft, Opt_hard, Opt_intr,
124 	Opt_nointr, Opt_posix, Opt_noposix, Opt_cto, Opt_nocto, Opt_ac,
125 	Opt_noac, Opt_lock, Opt_nolock, Opt_v2, Opt_v3, Opt_udp, Opt_tcp,
126 	Opt_acl, Opt_noacl,
127 	/* Error token */
128 	Opt_err
129 };
130 
131 static match_table_t __initdata tokens = {
132 	{Opt_port, "port=%u"},
133 	{Opt_rsize, "rsize=%u"},
134 	{Opt_wsize, "wsize=%u"},
135 	{Opt_timeo, "timeo=%u"},
136 	{Opt_retrans, "retrans=%u"},
137 	{Opt_acregmin, "acregmin=%u"},
138 	{Opt_acregmax, "acregmax=%u"},
139 	{Opt_acdirmin, "acdirmin=%u"},
140 	{Opt_acdirmax, "acdirmax=%u"},
141 	{Opt_soft, "soft"},
142 	{Opt_hard, "hard"},
143 	{Opt_intr, "intr"},
144 	{Opt_nointr, "nointr"},
145 	{Opt_posix, "posix"},
146 	{Opt_noposix, "noposix"},
147 	{Opt_cto, "cto"},
148 	{Opt_nocto, "nocto"},
149 	{Opt_ac, "ac"},
150 	{Opt_noac, "noac"},
151 	{Opt_lock, "lock"},
152 	{Opt_nolock, "nolock"},
153 	{Opt_v2, "nfsvers=2"},
154 	{Opt_v2, "v2"},
155 	{Opt_v3, "nfsvers=3"},
156 	{Opt_v3, "v3"},
157 	{Opt_udp, "proto=udp"},
158 	{Opt_udp, "udp"},
159 	{Opt_tcp, "proto=tcp"},
160 	{Opt_tcp, "tcp"},
161 	{Opt_acl, "acl"},
162 	{Opt_noacl, "noacl"},
163 	{Opt_err, NULL}
164 
165 };
166 
167 /*
168  *  Parse option string.
169  */
170 
171 static int __init root_nfs_parse(char *name, char *buf)
172 {
173 
174 	char *p;
175 	substring_t args[MAX_OPT_ARGS];
176 	int option;
177 
178 	if (!name)
179 		return 1;
180 
181 	/* Set the NFS remote path */
182 	p = strsep(&name, ",");
183 	if (p[0] != '\0' && strcmp(p, "default") != 0)
184 		strlcpy(buf, p, NFS_MAXPATHLEN);
185 
186 	while ((p = strsep (&name, ",")) != NULL) {
187 		int token;
188 		if (!*p)
189 			continue;
190 		token = match_token(p, tokens, args);
191 
192 		/* %u tokens only. Beware if you add new tokens! */
193 		if (token < Opt_soft && match_int(&args[0], &option))
194 			return 0;
195 		switch (token) {
196 			case Opt_port:
197 				nfs_port = option;
198 				break;
199 			case Opt_rsize:
200 				nfs_data.rsize = option;
201 				break;
202 			case Opt_wsize:
203 				nfs_data.wsize = option;
204 				break;
205 			case Opt_timeo:
206 				nfs_data.timeo = option;
207 				break;
208 			case Opt_retrans:
209 				nfs_data.retrans = option;
210 				break;
211 			case Opt_acregmin:
212 				nfs_data.acregmin = option;
213 				break;
214 			case Opt_acregmax:
215 				nfs_data.acregmax = option;
216 				break;
217 			case Opt_acdirmin:
218 				nfs_data.acdirmin = option;
219 				break;
220 			case Opt_acdirmax:
221 				nfs_data.acdirmax = option;
222 				break;
223 			case Opt_soft:
224 				nfs_data.flags |= NFS_MOUNT_SOFT;
225 				break;
226 			case Opt_hard:
227 				nfs_data.flags &= ~NFS_MOUNT_SOFT;
228 				break;
229 			case Opt_intr:
230 				nfs_data.flags |= NFS_MOUNT_INTR;
231 				break;
232 			case Opt_nointr:
233 				nfs_data.flags &= ~NFS_MOUNT_INTR;
234 				break;
235 			case Opt_posix:
236 				nfs_data.flags |= NFS_MOUNT_POSIX;
237 				break;
238 			case Opt_noposix:
239 				nfs_data.flags &= ~NFS_MOUNT_POSIX;
240 				break;
241 			case Opt_cto:
242 				nfs_data.flags &= ~NFS_MOUNT_NOCTO;
243 				break;
244 			case Opt_nocto:
245 				nfs_data.flags |= NFS_MOUNT_NOCTO;
246 				break;
247 			case Opt_ac:
248 				nfs_data.flags &= ~NFS_MOUNT_NOAC;
249 				break;
250 			case Opt_noac:
251 				nfs_data.flags |= NFS_MOUNT_NOAC;
252 				break;
253 			case Opt_lock:
254 				nfs_data.flags &= ~NFS_MOUNT_NONLM;
255 				break;
256 			case Opt_nolock:
257 				nfs_data.flags |= NFS_MOUNT_NONLM;
258 				break;
259 			case Opt_v2:
260 				nfs_data.flags &= ~NFS_MOUNT_VER3;
261 				break;
262 			case Opt_v3:
263 				nfs_data.flags |= NFS_MOUNT_VER3;
264 				break;
265 			case Opt_udp:
266 				nfs_data.flags &= ~NFS_MOUNT_TCP;
267 				break;
268 			case Opt_tcp:
269 				nfs_data.flags |= NFS_MOUNT_TCP;
270 				break;
271 			case Opt_acl:
272 				nfs_data.flags &= ~NFS_MOUNT_NOACL;
273 				break;
274 			case Opt_noacl:
275 				nfs_data.flags |= NFS_MOUNT_NOACL;
276 				break;
277 			default:
278 				printk(KERN_WARNING "Root-NFS: unknown "
279 					"option: %s\n", p);
280 				return 0;
281 		}
282 	}
283 
284 	return 1;
285 }
286 
287 /*
288  *  Prepare the NFS data structure and parse all options.
289  */
290 static int __init root_nfs_name(char *name)
291 {
292 	static char buf[NFS_MAXPATHLEN] __initdata;
293 	char *cp;
294 
295 	/* Set some default values */
296 	memset(&nfs_data, 0, sizeof(nfs_data));
297 	nfs_port          = -1;
298 	nfs_data.version  = NFS_MOUNT_VERSION;
299 	nfs_data.flags    = NFS_MOUNT_NONLM;	/* No lockd in nfs root yet */
300 	nfs_data.rsize    = NFS_DEF_FILE_IO_SIZE;
301 	nfs_data.wsize    = NFS_DEF_FILE_IO_SIZE;
302 	nfs_data.acregmin = 3;
303 	nfs_data.acregmax = 60;
304 	nfs_data.acdirmin = 30;
305 	nfs_data.acdirmax = 60;
306 	strcpy(buf, NFS_ROOT);
307 
308 	/* Process options received from the remote server */
309 	root_nfs_parse(root_server_path, buf);
310 
311 	/* Override them by options set on kernel command-line */
312 	root_nfs_parse(name, buf);
313 
314 	cp = utsname()->nodename;
315 	if (strlen(buf) + strlen(cp) > NFS_MAXPATHLEN) {
316 		printk(KERN_ERR "Root-NFS: Pathname for remote directory too long.\n");
317 		return -1;
318 	}
319 	sprintf(nfs_path, buf, cp);
320 
321 	return 1;
322 }
323 
324 
325 /*
326  *  Get NFS server address.
327  */
328 static int __init root_nfs_addr(void)
329 {
330 	if ((servaddr = root_server_addr) == htonl(INADDR_NONE)) {
331 		printk(KERN_ERR "Root-NFS: No NFS server available, giving up.\n");
332 		return -1;
333 	}
334 
335 	snprintf(nfs_data.hostname, sizeof(nfs_data.hostname),
336 		 "%u.%u.%u.%u", NIPQUAD(servaddr));
337 	return 0;
338 }
339 
340 /*
341  *  Tell the user what's going on.
342  */
343 #ifdef NFSROOT_DEBUG
344 static void __init root_nfs_print(void)
345 {
346 	printk(KERN_NOTICE "Root-NFS: Mounting %s on server %s as root\n",
347 		nfs_path, nfs_data.hostname);
348 	printk(KERN_NOTICE "Root-NFS:     rsize = %d, wsize = %d, timeo = %d, retrans = %d\n",
349 		nfs_data.rsize, nfs_data.wsize, nfs_data.timeo, nfs_data.retrans);
350 	printk(KERN_NOTICE "Root-NFS:     acreg (min,max) = (%d,%d), acdir (min,max) = (%d,%d)\n",
351 		nfs_data.acregmin, nfs_data.acregmax,
352 		nfs_data.acdirmin, nfs_data.acdirmax);
353 	printk(KERN_NOTICE "Root-NFS:     nfsd port = %d, mountd port = %d, flags = %08x\n",
354 		nfs_port, mount_port, nfs_data.flags);
355 }
356 #endif
357 
358 
359 static int __init root_nfs_init(void)
360 {
361 #ifdef NFSROOT_DEBUG
362 	nfs_debug |= NFSDBG_ROOT;
363 #endif
364 
365 	/*
366 	 * Decode the root directory path name and NFS options from
367 	 * the kernel command line. This has to go here in order to
368 	 * be able to use the client IP address for the remote root
369 	 * directory (necessary for pure RARP booting).
370 	 */
371 	if (root_nfs_name(nfs_root_name) < 0 ||
372 	    root_nfs_addr() < 0)
373 		return -1;
374 
375 #ifdef NFSROOT_DEBUG
376 	root_nfs_print();
377 #endif
378 
379 	return 0;
380 }
381 
382 
383 /*
384  *  Parse NFS server and directory information passed on the kernel
385  *  command line.
386  */
387 static int __init nfs_root_setup(char *line)
388 {
389 	ROOT_DEV = Root_NFS;
390 	if (line[0] == '/' || line[0] == ',' || (line[0] >= '0' && line[0] <= '9')) {
391 		strlcpy(nfs_root_name, line, sizeof(nfs_root_name));
392 	} else {
393 		int n = strlen(line) + sizeof(NFS_ROOT) - 1;
394 		if (n >= sizeof(nfs_root_name))
395 			line[sizeof(nfs_root_name) - sizeof(NFS_ROOT) - 2] = '\0';
396 		sprintf(nfs_root_name, NFS_ROOT, line);
397 	}
398 	root_server_addr = root_nfs_parse_addr(nfs_root_name);
399 	return 1;
400 }
401 
402 __setup("nfsroot=", nfs_root_setup);
403 
404 /***************************************************************************
405 
406 	       Routines to actually mount the root directory
407 
408  ***************************************************************************/
409 
410 /*
411  *  Construct sockaddr_in from address and port number.
412  */
413 static inline void
414 set_sockaddr(struct sockaddr_in *sin, __be32 addr, __be16 port)
415 {
416 	sin->sin_family = AF_INET;
417 	sin->sin_addr.s_addr = addr;
418 	sin->sin_port = port;
419 }
420 
421 /*
422  *  Query server portmapper for the port of a daemon program.
423  */
424 static int __init root_nfs_getport(int program, int version, int proto)
425 {
426 	struct sockaddr_in sin;
427 
428 	printk(KERN_NOTICE "Looking up port of RPC %d/%d on %u.%u.%u.%u\n",
429 		program, version, NIPQUAD(servaddr));
430 	set_sockaddr(&sin, servaddr, 0);
431 	return rpcb_getport_external(&sin, program, version, proto);
432 }
433 
434 
435 /*
436  *  Use portmapper to find mountd and nfsd port numbers if not overriden
437  *  by the user. Use defaults if portmapper is not available.
438  *  XXX: Is there any nfs server with no portmapper?
439  */
440 static int __init root_nfs_ports(void)
441 {
442 	int port;
443 	int nfsd_ver, mountd_ver;
444 	int nfsd_port, mountd_port;
445 	int proto;
446 
447 	if (nfs_data.flags & NFS_MOUNT_VER3) {
448 		nfsd_ver = NFS3_VERSION;
449 		mountd_ver = NFS_MNT3_VERSION;
450 		nfsd_port = NFS_PORT;
451 		mountd_port = NFS_MNT_PORT;
452 	} else {
453 		nfsd_ver = NFS2_VERSION;
454 		mountd_ver = NFS_MNT_VERSION;
455 		nfsd_port = NFS_PORT;
456 		mountd_port = NFS_MNT_PORT;
457 	}
458 
459 	proto = (nfs_data.flags & NFS_MOUNT_TCP) ? IPPROTO_TCP : IPPROTO_UDP;
460 
461 	if (nfs_port < 0) {
462 		if ((port = root_nfs_getport(NFS_PROGRAM, nfsd_ver, proto)) < 0) {
463 			printk(KERN_ERR "Root-NFS: Unable to get nfsd port "
464 					"number from server, using default\n");
465 			port = nfsd_port;
466 		}
467 		nfs_port = port;
468 		dprintk("Root-NFS: Portmapper on server returned %d "
469 			"as nfsd port\n", port);
470 	}
471 
472 	if ((port = root_nfs_getport(NFS_MNT_PROGRAM, mountd_ver, proto)) < 0) {
473 		printk(KERN_ERR "Root-NFS: Unable to get mountd port "
474 				"number from server, using default\n");
475 		port = mountd_port;
476 	}
477 	mount_port = port;
478 	dprintk("Root-NFS: mountd port is %d\n", port);
479 
480 	return 0;
481 }
482 
483 
484 /*
485  *  Get a file handle from the server for the directory which is to be
486  *  mounted.
487  */
488 static int __init root_nfs_get_handle(void)
489 {
490 	struct nfs_fh fh;
491 	struct sockaddr_in sin;
492 	int status;
493 	int protocol = (nfs_data.flags & NFS_MOUNT_TCP) ?
494 					IPPROTO_TCP : IPPROTO_UDP;
495 	int version = (nfs_data.flags & NFS_MOUNT_VER3) ?
496 					NFS_MNT3_VERSION : NFS_MNT_VERSION;
497 
498 	set_sockaddr(&sin, servaddr, htons(mount_port));
499 	status = nfsroot_mount(&sin, nfs_path, &fh, version, protocol);
500 	if (status < 0)
501 		printk(KERN_ERR "Root-NFS: Server returned error %d "
502 				"while mounting %s\n", status, nfs_path);
503 	else {
504 		nfs_data.root.size = fh.size;
505 		memcpy(nfs_data.root.data, fh.data, fh.size);
506 	}
507 
508 	return status;
509 }
510 
511 /*
512  *  Get the NFS port numbers and file handle, and return the prepared 'data'
513  *  argument for mount() if everything went OK. Return NULL otherwise.
514  */
515 void * __init nfs_root_data(void)
516 {
517 	if (root_nfs_init() < 0
518 	 || root_nfs_ports() < 0
519 	 || root_nfs_get_handle() < 0)
520 		return NULL;
521 	set_sockaddr((struct sockaddr_in *) &nfs_data.addr, servaddr, htons(nfs_port));
522 	return (void*)&nfs_data;
523 }
524