xref: /openbmc/linux/fs/nfs/nfsroot.c (revision 9d56dd3b083a3bec56e9da35ce07baca81030b03)
1 /*
2  *  Copyright (C) 1995, 1996  Gero Kuhlmann <gero@gkminix.han.de>
3  *
4  *  Allow an NFS filesystem to be mounted as root. The way this works is:
5  *     (1) Use the IP autoconfig mechanism to set local IP addresses and routes.
6  *     (2) Handle RPC negotiation with the system which replied to RARP or
7  *         was reported as a boot server by BOOTP or manually.
8  *     (3) The actual mounting is done later, when init() is running.
9  *
10  *
11  *	Changes:
12  *
13  *	Alan Cox	:	Removed get_address name clash with FPU.
14  *	Alan Cox	:	Reformatted a bit.
15  *	Gero Kuhlmann	:	Code cleanup
16  *	Michael Rausch  :	Fixed recognition of an incoming RARP answer.
17  *	Martin Mares	: (2.0)	Auto-configuration via BOOTP supported.
18  *	Martin Mares	:	Manual selection of interface & BOOTP/RARP.
19  *	Martin Mares	:	Using network routes instead of host routes,
20  *				allowing the default configuration to be used
21  *				for normal operation of the host.
22  *	Martin Mares	:	Randomized timer with exponential backoff
23  *				installed to minimize network congestion.
24  *	Martin Mares	:	Code cleanup.
25  *	Martin Mares	: (2.1)	BOOTP and RARP made configuration options.
26  *	Martin Mares	:	Server hostname generation fixed.
27  *	Gerd Knorr	:	Fixed wired inode handling
28  *	Martin Mares	: (2.2)	"0.0.0.0" addresses from command line ignored.
29  *	Martin Mares	:	RARP replies not tested for server address.
30  *	Gero Kuhlmann	: (2.3) Some bug fixes and code cleanup again (please
31  *				send me your new patches _before_ bothering
32  *				Linus so that I don' always have to cleanup
33  *				_afterwards_ - thanks)
34  *	Gero Kuhlmann	:	Last changes of Martin Mares undone.
35  *	Gero Kuhlmann	: 	RARP replies are tested for specified server
36  *				again. However, it's now possible to have
37  *				different RARP and NFS servers.
38  *	Gero Kuhlmann	:	"0.0.0.0" addresses from command line are
39  *				now mapped to INADDR_NONE.
40  *	Gero Kuhlmann	:	Fixed a bug which prevented BOOTP path name
41  *				from being used (thanks to Leo Spiekman)
42  *	Andy Walker	:	Allow to specify the NFS server in nfs_root
43  *				without giving a path name
44  *	Swen Thümmler	:	Allow to specify the NFS options in nfs_root
45  *				without giving a path name. Fix BOOTP request
46  *				for domainname (domainname is NIS domain, not
47  *				DNS domain!). Skip dummy devices for BOOTP.
48  *	Jacek Zapala	:	Fixed a bug which prevented server-ip address
49  *				from nfsroot parameter from being used.
50  *	Olaf Kirch	:	Adapted to new NFS code.
51  *	Jakub Jelinek	:	Free used code segment.
52  *	Marko Kohtala	:	Fixed some bugs.
53  *	Martin Mares	:	Debug message cleanup
54  *	Martin Mares	:	Changed to use the new generic IP layer autoconfig
55  *				code. BOOTP and RARP moved there.
56  *	Martin Mares	:	Default path now contains host name instead of
57  *				host IP address (but host name defaults to IP
58  *				address anyway).
59  *	Martin Mares	:	Use root_server_addr appropriately during setup.
60  *	Martin Mares	:	Rewrote parameter parsing, now hopefully giving
61  *				correct overriding.
62  *	Trond Myklebust :	Add in preliminary support for NFSv3 and TCP.
63  *				Fix bug in root_nfs_addr(). nfs_data.namlen
64  *				is NOT for the length of the hostname.
65  *	Hua Qin		:	Support for mounting root file system via
66  *				NFS over TCP.
67  *	Fabian Frederick:	Option parser rebuilt (using parser lib)
68 */
69 
70 #include <linux/types.h>
71 #include <linux/string.h>
72 #include <linux/kernel.h>
73 #include <linux/time.h>
74 #include <linux/fs.h>
75 #include <linux/init.h>
76 #include <linux/sunrpc/clnt.h>
77 #include <linux/sunrpc/xprtsock.h>
78 #include <linux/nfs.h>
79 #include <linux/nfs_fs.h>
80 #include <linux/nfs_mount.h>
81 #include <linux/in.h>
82 #include <linux/major.h>
83 #include <linux/utsname.h>
84 #include <linux/inet.h>
85 #include <linux/root_dev.h>
86 #include <net/ipconfig.h>
87 #include <linux/parser.h>
88 
89 #include "internal.h"
90 
91 /* Define this to allow debugging output */
92 #undef NFSROOT_DEBUG
93 #define NFSDBG_FACILITY NFSDBG_ROOT
94 
95 /* Default port to use if server is not running a portmapper */
96 #define NFS_MNT_PORT	627
97 
98 /* Default path we try to mount. "%s" gets replaced by our IP address */
99 #define NFS_ROOT		"/tftpboot/%s"
100 
101 /* Parameters passed from the kernel command line */
102 static char nfs_root_name[256] __initdata = "";
103 
104 /* Address of NFS server */
105 static __be32 servaddr __initdata = 0;
106 
107 /* Name of directory to mount */
108 static char nfs_export_path[NFS_MAXPATHLEN] __initdata = { 0, };
109 
110 /* NFS-related data */
111 static struct nfs_mount_data nfs_data __initdata = { 0, };/* NFS mount info */
112 static int nfs_port __initdata = 0;		/* Port to connect to for NFS */
113 static int mount_port __initdata = 0;		/* Mount daemon port number */
114 
115 
116 /***************************************************************************
117 
118 			     Parsing of options
119 
120  ***************************************************************************/
121 
122 enum {
123 	/* Options that take integer arguments */
124 	Opt_port, Opt_rsize, Opt_wsize, Opt_timeo, Opt_retrans, Opt_acregmin,
125 	Opt_acregmax, Opt_acdirmin, Opt_acdirmax,
126 	/* Options that take no arguments */
127 	Opt_soft, Opt_hard, Opt_intr,
128 	Opt_nointr, Opt_posix, Opt_noposix, Opt_cto, Opt_nocto, Opt_ac,
129 	Opt_noac, Opt_lock, Opt_nolock, Opt_v2, Opt_v3, Opt_udp, Opt_tcp,
130 	Opt_acl, Opt_noacl,
131 	/* Error token */
132 	Opt_err
133 };
134 
135 static const match_table_t tokens __initconst = {
136 	{Opt_port, "port=%u"},
137 	{Opt_rsize, "rsize=%u"},
138 	{Opt_wsize, "wsize=%u"},
139 	{Opt_timeo, "timeo=%u"},
140 	{Opt_retrans, "retrans=%u"},
141 	{Opt_acregmin, "acregmin=%u"},
142 	{Opt_acregmax, "acregmax=%u"},
143 	{Opt_acdirmin, "acdirmin=%u"},
144 	{Opt_acdirmax, "acdirmax=%u"},
145 	{Opt_soft, "soft"},
146 	{Opt_hard, "hard"},
147 	{Opt_intr, "intr"},
148 	{Opt_nointr, "nointr"},
149 	{Opt_posix, "posix"},
150 	{Opt_noposix, "noposix"},
151 	{Opt_cto, "cto"},
152 	{Opt_nocto, "nocto"},
153 	{Opt_ac, "ac"},
154 	{Opt_noac, "noac"},
155 	{Opt_lock, "lock"},
156 	{Opt_nolock, "nolock"},
157 	{Opt_v2, "nfsvers=2"},
158 	{Opt_v2, "v2"},
159 	{Opt_v3, "nfsvers=3"},
160 	{Opt_v3, "v3"},
161 	{Opt_udp, "proto=udp"},
162 	{Opt_udp, "udp"},
163 	{Opt_tcp, "proto=tcp"},
164 	{Opt_tcp, "tcp"},
165 	{Opt_acl, "acl"},
166 	{Opt_noacl, "noacl"},
167 	{Opt_err, NULL}
168 
169 };
170 
171 /*
172  *  Parse option string.
173  */
174 
175 static int __init root_nfs_parse(char *name, char *buf)
176 {
177 
178 	char *p;
179 	substring_t args[MAX_OPT_ARGS];
180 	int option;
181 
182 	if (!name)
183 		return 1;
184 
185 	/* Set the NFS remote path */
186 	p = strsep(&name, ",");
187 	if (p[0] != '\0' && strcmp(p, "default") != 0)
188 		strlcpy(buf, p, NFS_MAXPATHLEN);
189 
190 	while ((p = strsep (&name, ",")) != NULL) {
191 		int token;
192 		if (!*p)
193 			continue;
194 		token = match_token(p, tokens, args);
195 
196 		/* %u tokens only. Beware if you add new tokens! */
197 		if (token < Opt_soft && match_int(&args[0], &option))
198 			return 0;
199 		switch (token) {
200 			case Opt_port:
201 				nfs_port = option;
202 				break;
203 			case Opt_rsize:
204 				nfs_data.rsize = option;
205 				break;
206 			case Opt_wsize:
207 				nfs_data.wsize = option;
208 				break;
209 			case Opt_timeo:
210 				nfs_data.timeo = option;
211 				break;
212 			case Opt_retrans:
213 				nfs_data.retrans = option;
214 				break;
215 			case Opt_acregmin:
216 				nfs_data.acregmin = option;
217 				break;
218 			case Opt_acregmax:
219 				nfs_data.acregmax = option;
220 				break;
221 			case Opt_acdirmin:
222 				nfs_data.acdirmin = option;
223 				break;
224 			case Opt_acdirmax:
225 				nfs_data.acdirmax = option;
226 				break;
227 			case Opt_soft:
228 				nfs_data.flags |= NFS_MOUNT_SOFT;
229 				break;
230 			case Opt_hard:
231 				nfs_data.flags &= ~NFS_MOUNT_SOFT;
232 				break;
233 			case Opt_intr:
234 			case Opt_nointr:
235 				break;
236 			case Opt_posix:
237 				nfs_data.flags |= NFS_MOUNT_POSIX;
238 				break;
239 			case Opt_noposix:
240 				nfs_data.flags &= ~NFS_MOUNT_POSIX;
241 				break;
242 			case Opt_cto:
243 				nfs_data.flags &= ~NFS_MOUNT_NOCTO;
244 				break;
245 			case Opt_nocto:
246 				nfs_data.flags |= NFS_MOUNT_NOCTO;
247 				break;
248 			case Opt_ac:
249 				nfs_data.flags &= ~NFS_MOUNT_NOAC;
250 				break;
251 			case Opt_noac:
252 				nfs_data.flags |= NFS_MOUNT_NOAC;
253 				break;
254 			case Opt_lock:
255 				nfs_data.flags &= ~NFS_MOUNT_NONLM;
256 				break;
257 			case Opt_nolock:
258 				nfs_data.flags |= NFS_MOUNT_NONLM;
259 				break;
260 			case Opt_v2:
261 				nfs_data.flags &= ~NFS_MOUNT_VER3;
262 				break;
263 			case Opt_v3:
264 				nfs_data.flags |= NFS_MOUNT_VER3;
265 				break;
266 			case Opt_udp:
267 				nfs_data.flags &= ~NFS_MOUNT_TCP;
268 				break;
269 			case Opt_tcp:
270 				nfs_data.flags |= NFS_MOUNT_TCP;
271 				break;
272 			case Opt_acl:
273 				nfs_data.flags &= ~NFS_MOUNT_NOACL;
274 				break;
275 			case Opt_noacl:
276 				nfs_data.flags |= NFS_MOUNT_NOACL;
277 				break;
278 			default:
279 				printk(KERN_WARNING "Root-NFS: unknown "
280 					"option: %s\n", p);
281 				return 0;
282 		}
283 	}
284 
285 	return 1;
286 }
287 
288 /*
289  *  Prepare the NFS data structure and parse all options.
290  */
291 static int __init root_nfs_name(char *name)
292 {
293 	static char buf[NFS_MAXPATHLEN] __initdata;
294 	char *cp;
295 
296 	/* Set some default values */
297 	memset(&nfs_data, 0, sizeof(nfs_data));
298 	nfs_port          = -1;
299 	nfs_data.version  = NFS_MOUNT_VERSION;
300 	nfs_data.flags    = NFS_MOUNT_NONLM;	/* No lockd in nfs root yet */
301 	nfs_data.rsize    = NFS_DEF_FILE_IO_SIZE;
302 	nfs_data.wsize    = NFS_DEF_FILE_IO_SIZE;
303 	nfs_data.acregmin = NFS_DEF_ACREGMIN;
304 	nfs_data.acregmax = NFS_DEF_ACREGMAX;
305 	nfs_data.acdirmin = NFS_DEF_ACDIRMIN;
306 	nfs_data.acdirmax = NFS_DEF_ACDIRMAX;
307 	strcpy(buf, NFS_ROOT);
308 
309 	/* Process options received from the remote server */
310 	root_nfs_parse(root_server_path, buf);
311 
312 	/* Override them by options set on kernel command-line */
313 	root_nfs_parse(name, buf);
314 
315 	cp = utsname()->nodename;
316 	if (strlen(buf) + strlen(cp) > NFS_MAXPATHLEN) {
317 		printk(KERN_ERR "Root-NFS: Pathname for remote directory too long.\n");
318 		return -1;
319 	}
320 	sprintf(nfs_export_path, buf, cp);
321 
322 	return 1;
323 }
324 
325 
326 /*
327  *  Get NFS server address.
328  */
329 static int __init root_nfs_addr(void)
330 {
331 	if ((servaddr = root_server_addr) == htonl(INADDR_NONE)) {
332 		printk(KERN_ERR "Root-NFS: No NFS server available, giving up.\n");
333 		return -1;
334 	}
335 
336 	snprintf(nfs_data.hostname, sizeof(nfs_data.hostname),
337 		 "%pI4", &servaddr);
338 	return 0;
339 }
340 
341 /*
342  *  Tell the user what's going on.
343  */
344 #ifdef NFSROOT_DEBUG
345 static void __init root_nfs_print(void)
346 {
347 	printk(KERN_NOTICE "Root-NFS: Mounting %s on server %s as root\n",
348 		nfs_export_path, nfs_data.hostname);
349 	printk(KERN_NOTICE "Root-NFS:     rsize = %d, wsize = %d, timeo = %d, retrans = %d\n",
350 		nfs_data.rsize, nfs_data.wsize, nfs_data.timeo, nfs_data.retrans);
351 	printk(KERN_NOTICE "Root-NFS:     acreg (min,max) = (%d,%d), acdir (min,max) = (%d,%d)\n",
352 		nfs_data.acregmin, nfs_data.acregmax,
353 		nfs_data.acdirmin, nfs_data.acdirmax);
354 	printk(KERN_NOTICE "Root-NFS:     nfsd port = %d, mountd port = %d, flags = %08x\n",
355 		nfs_port, mount_port, nfs_data.flags);
356 }
357 #endif
358 
359 
360 static int __init root_nfs_init(void)
361 {
362 #ifdef NFSROOT_DEBUG
363 	nfs_debug |= NFSDBG_ROOT;
364 #endif
365 
366 	/*
367 	 * Decode the root directory path name and NFS options from
368 	 * the kernel command line. This has to go here in order to
369 	 * be able to use the client IP address for the remote root
370 	 * directory (necessary for pure RARP booting).
371 	 */
372 	if (root_nfs_name(nfs_root_name) < 0 ||
373 	    root_nfs_addr() < 0)
374 		return -1;
375 
376 #ifdef NFSROOT_DEBUG
377 	root_nfs_print();
378 #endif
379 
380 	return 0;
381 }
382 
383 
384 /*
385  *  Parse NFS server and directory information passed on the kernel
386  *  command line.
387  */
388 static int __init nfs_root_setup(char *line)
389 {
390 	ROOT_DEV = Root_NFS;
391 	if (line[0] == '/' || line[0] == ',' || (line[0] >= '0' && line[0] <= '9')) {
392 		strlcpy(nfs_root_name, line, sizeof(nfs_root_name));
393 	} else {
394 		int n = strlen(line) + sizeof(NFS_ROOT) - 1;
395 		if (n >= sizeof(nfs_root_name))
396 			line[sizeof(nfs_root_name) - sizeof(NFS_ROOT) - 2] = '\0';
397 		sprintf(nfs_root_name, NFS_ROOT, line);
398 	}
399 	root_server_addr = root_nfs_parse_addr(nfs_root_name);
400 	return 1;
401 }
402 
403 __setup("nfsroot=", nfs_root_setup);
404 
405 /***************************************************************************
406 
407 	       Routines to actually mount the root directory
408 
409  ***************************************************************************/
410 
411 /*
412  *  Construct sockaddr_in from address and port number.
413  */
414 static inline void
415 set_sockaddr(struct sockaddr_in *sin, __be32 addr, __be16 port)
416 {
417 	sin->sin_family = AF_INET;
418 	sin->sin_addr.s_addr = addr;
419 	sin->sin_port = port;
420 }
421 
422 /*
423  *  Query server portmapper for the port of a daemon program.
424  */
425 static int __init root_nfs_getport(int program, int version, int proto)
426 {
427 	struct sockaddr_in sin;
428 
429 	printk(KERN_NOTICE "Looking up port of RPC %d/%d on %pI4\n",
430 		program, version, &servaddr);
431 	set_sockaddr(&sin, servaddr, 0);
432 	return rpcb_getport_sync(&sin, program, version, proto);
433 }
434 
435 
436 /*
437  *  Use portmapper to find mountd and nfsd port numbers if not overriden
438  *  by the user. Use defaults if portmapper is not available.
439  *  XXX: Is there any nfs server with no portmapper?
440  */
441 static int __init root_nfs_ports(void)
442 {
443 	int port;
444 	int nfsd_ver, mountd_ver;
445 	int nfsd_port, mountd_port;
446 	int proto;
447 
448 	if (nfs_data.flags & NFS_MOUNT_VER3) {
449 		nfsd_ver = NFS3_VERSION;
450 		mountd_ver = NFS_MNT3_VERSION;
451 		nfsd_port = NFS_PORT;
452 		mountd_port = NFS_MNT_PORT;
453 	} else {
454 		nfsd_ver = NFS2_VERSION;
455 		mountd_ver = NFS_MNT_VERSION;
456 		nfsd_port = NFS_PORT;
457 		mountd_port = NFS_MNT_PORT;
458 	}
459 
460 	proto = (nfs_data.flags & NFS_MOUNT_TCP) ? IPPROTO_TCP : IPPROTO_UDP;
461 
462 	if (nfs_port < 0) {
463 		if ((port = root_nfs_getport(NFS_PROGRAM, nfsd_ver, proto)) < 0) {
464 			printk(KERN_ERR "Root-NFS: Unable to get nfsd port "
465 					"number from server, using default\n");
466 			port = nfsd_port;
467 		}
468 		nfs_port = port;
469 		dprintk("Root-NFS: Portmapper on server returned %d "
470 			"as nfsd port\n", port);
471 	}
472 
473 	if ((port = root_nfs_getport(NFS_MNT_PROGRAM, mountd_ver, proto)) < 0) {
474 		printk(KERN_ERR "Root-NFS: Unable to get mountd port "
475 				"number from server, using default\n");
476 		port = mountd_port;
477 	}
478 	mount_port = port;
479 	dprintk("Root-NFS: mountd port is %d\n", port);
480 
481 	return 0;
482 }
483 
484 
485 /*
486  *  Get a file handle from the server for the directory which is to be
487  *  mounted.
488  */
489 static int __init root_nfs_get_handle(void)
490 {
491 	struct nfs_fh fh;
492 	struct sockaddr_in sin;
493 	unsigned int auth_flav_len = 0;
494 	struct nfs_mount_request request = {
495 		.sap		= (struct sockaddr *)&sin,
496 		.salen		= sizeof(sin),
497 		.dirpath	= nfs_export_path,
498 		.version	= (nfs_data.flags & NFS_MOUNT_VER3) ?
499 					NFS_MNT3_VERSION : NFS_MNT_VERSION,
500 		.protocol	= (nfs_data.flags & NFS_MOUNT_TCP) ?
501 					XPRT_TRANSPORT_TCP : XPRT_TRANSPORT_UDP,
502 		.fh		= &fh,
503 		.auth_flav_len	= &auth_flav_len,
504 	};
505 	int status;
506 
507 	set_sockaddr(&sin, servaddr, htons(mount_port));
508 	status = nfs_mount(&request);
509 	if (status < 0)
510 		printk(KERN_ERR "Root-NFS: Server returned error %d "
511 				"while mounting %s\n", status, nfs_export_path);
512 	else {
513 		nfs_data.root.size = fh.size;
514 		memcpy(nfs_data.root.data, fh.data, fh.size);
515 	}
516 
517 	return status;
518 }
519 
520 /*
521  *  Get the NFS port numbers and file handle, and return the prepared 'data'
522  *  argument for mount() if everything went OK. Return NULL otherwise.
523  */
524 void * __init nfs_root_data(void)
525 {
526 	if (root_nfs_init() < 0
527 	 || root_nfs_ports() < 0
528 	 || root_nfs_get_handle() < 0)
529 		return NULL;
530 	set_sockaddr((struct sockaddr_in *) &nfs_data.addr, servaddr, htons(nfs_port));
531 	return (void*)&nfs_data;
532 }
533