xref: /openbmc/linux/fs/nfs/nfsroot.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
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/config.h>
73 #include <linux/types.h>
74 #include <linux/string.h>
75 #include <linux/kernel.h>
76 #include <linux/time.h>
77 #include <linux/fs.h>
78 #include <linux/init.h>
79 #include <linux/sunrpc/clnt.h>
80 #include <linux/nfs.h>
81 #include <linux/nfs_fs.h>
82 #include <linux/nfs_mount.h>
83 #include <linux/in.h>
84 #include <linux/major.h>
85 #include <linux/utsname.h>
86 #include <linux/inet.h>
87 #include <linux/root_dev.h>
88 #include <net/ipconfig.h>
89 #include <linux/parser.h>
90 
91 /* Define this to allow debugging output */
92 #undef NFSROOT_DEBUG
93 #define NFSDBG_FACILITY NFSDBG_ROOT
94 
95 /* Default path we try to mount. "%s" gets replaced by our IP address */
96 #define NFS_ROOT		"/tftpboot/%s"
97 
98 /* Parameters passed from the kernel command line */
99 static char nfs_root_name[256] __initdata = "";
100 
101 /* Address of NFS server */
102 static __u32 servaddr __initdata = 0;
103 
104 /* Name of directory to mount */
105 static char nfs_path[NFS_MAXPATHLEN] __initdata = { 0, };
106 
107 /* NFS-related data */
108 static struct nfs_mount_data nfs_data __initdata = { 0, };/* NFS mount info */
109 static int nfs_port __initdata = 0;		/* Port to connect to for NFS */
110 static int mount_port __initdata = 0;		/* Mount daemon port number */
111 
112 
113 /***************************************************************************
114 
115 			     Parsing of options
116 
117  ***************************************************************************/
118 
119 enum {
120 	/* Options that take integer arguments */
121 	Opt_port, Opt_rsize, Opt_wsize, Opt_timeo, Opt_retrans, Opt_acregmin,
122 	Opt_acregmax, Opt_acdirmin, Opt_acdirmax,
123 	/* Options that take no arguments */
124 	Opt_soft, Opt_hard, Opt_intr,
125 	Opt_nointr, Opt_posix, Opt_noposix, Opt_cto, Opt_nocto, Opt_ac,
126 	Opt_noac, Opt_lock, Opt_nolock, Opt_v2, Opt_v3, Opt_udp, Opt_tcp,
127 	Opt_acl, Opt_noacl,
128 	/* Error token */
129 	Opt_err
130 };
131 
132 static match_table_t __initdata tokens = {
133 	{Opt_port, "port=%u"},
134 	{Opt_rsize, "rsize=%u"},
135 	{Opt_wsize, "wsize=%u"},
136 	{Opt_timeo, "timeo=%u"},
137 	{Opt_retrans, "retrans=%u"},
138 	{Opt_acregmin, "acregmin=%u"},
139 	{Opt_acregmax, "acregmax=%u"},
140 	{Opt_acdirmin, "acdirmin=%u"},
141 	{Opt_acdirmax, "acdirmax=%u"},
142 	{Opt_soft, "soft"},
143 	{Opt_hard, "hard"},
144 	{Opt_intr, "intr"},
145 	{Opt_nointr, "nointr"},
146 	{Opt_posix, "posix"},
147 	{Opt_noposix, "noposix"},
148 	{Opt_cto, "cto"},
149 	{Opt_nocto, "nocto"},
150 	{Opt_ac, "ac"},
151 	{Opt_noac, "noac"},
152 	{Opt_lock, "lock"},
153 	{Opt_nolock, "nolock"},
154 	{Opt_v2, "nfsvers=2"},
155 	{Opt_v2, "v2"},
156 	{Opt_v3, "nfsvers=3"},
157 	{Opt_v3, "v3"},
158 	{Opt_udp, "proto=udp"},
159 	{Opt_udp, "udp"},
160 	{Opt_tcp, "proto=tcp"},
161 	{Opt_tcp, "tcp"},
162 	{Opt_acl, "acl"},
163 	{Opt_noacl, "noacl"},
164 	{Opt_err, NULL}
165 
166 };
167 
168 /*
169  *  Parse option string.
170  */
171 
172 static int __init root_nfs_parse(char *name, char *buf)
173 {
174 
175 	char *p;
176 	substring_t args[MAX_OPT_ARGS];
177 	int option;
178 
179 	if (!name)
180 		return 1;
181 
182 	/* Set the NFS remote path */
183 	p = strsep(&name, ",");
184 	if (p[0] != '\0' && strcmp(p, "default") != 0)
185 		strlcpy(buf, p, NFS_MAXPATHLEN);
186 
187 	while ((p = strsep (&name, ",")) != NULL) {
188 		int token;
189 		if (!*p)
190 			continue;
191 		token = match_token(p, tokens, args);
192 
193 		/* %u tokens only. Beware if you add new tokens! */
194 		if (token < Opt_soft && match_int(&args[0], &option))
195 			return 0;
196 		switch (token) {
197 			case Opt_port:
198 				nfs_port = option;
199 				break;
200 			case Opt_rsize:
201 				nfs_data.rsize = option;
202 				break;
203 			case Opt_wsize:
204 				nfs_data.wsize = option;
205 				break;
206 			case Opt_timeo:
207 				nfs_data.timeo = option;
208 				break;
209 			case Opt_retrans:
210 				nfs_data.retrans = option;
211 				break;
212 			case Opt_acregmin:
213 				nfs_data.acregmin = option;
214 				break;
215 			case Opt_acregmax:
216 				nfs_data.acregmax = option;
217 				break;
218 			case Opt_acdirmin:
219 				nfs_data.acdirmin = option;
220 				break;
221 			case Opt_acdirmax:
222 				nfs_data.acdirmax = option;
223 				break;
224 			case Opt_soft:
225 				nfs_data.flags |= NFS_MOUNT_SOFT;
226 				break;
227 			case Opt_hard:
228 				nfs_data.flags &= ~NFS_MOUNT_SOFT;
229 				break;
230 			case Opt_intr:
231 				nfs_data.flags |= NFS_MOUNT_INTR;
232 				break;
233 			case Opt_nointr:
234 				nfs_data.flags &= ~NFS_MOUNT_INTR;
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 				return 0;
280 		}
281 	}
282 
283 	return 1;
284 }
285 
286 /*
287  *  Prepare the NFS data structure and parse all options.
288  */
289 static int __init root_nfs_name(char *name)
290 {
291 	static char buf[NFS_MAXPATHLEN] __initdata;
292 	char *cp;
293 
294 	/* Set some default values */
295 	memset(&nfs_data, 0, sizeof(nfs_data));
296 	nfs_port          = -1;
297 	nfs_data.version  = NFS_MOUNT_VERSION;
298 	nfs_data.flags    = NFS_MOUNT_NONLM;	/* No lockd in nfs root yet */
299 	nfs_data.rsize    = NFS_DEF_FILE_IO_BUFFER_SIZE;
300 	nfs_data.wsize    = NFS_DEF_FILE_IO_BUFFER_SIZE;
301 	nfs_data.acregmin = 3;
302 	nfs_data.acregmax = 60;
303 	nfs_data.acdirmin = 30;
304 	nfs_data.acdirmax = 60;
305 	strcpy(buf, NFS_ROOT);
306 
307 	/* Process options received from the remote server */
308 	root_nfs_parse(root_server_path, buf);
309 
310 	/* Override them by options set on kernel command-line */
311 	root_nfs_parse(name, buf);
312 
313 	cp = system_utsname.nodename;
314 	if (strlen(buf) + strlen(cp) > NFS_MAXPATHLEN) {
315 		printk(KERN_ERR "Root-NFS: Pathname for remote directory too long.\n");
316 		return -1;
317 	}
318 	sprintf(nfs_path, buf, cp);
319 
320 	return 1;
321 }
322 
323 
324 /*
325  *  Get NFS server address.
326  */
327 static int __init root_nfs_addr(void)
328 {
329 	if ((servaddr = root_server_addr) == INADDR_NONE) {
330 		printk(KERN_ERR "Root-NFS: No NFS server available, giving up.\n");
331 		return -1;
332 	}
333 
334 	snprintf(nfs_data.hostname, sizeof(nfs_data.hostname),
335 		 "%u.%u.%u.%u", NIPQUAD(servaddr));
336 	return 0;
337 }
338 
339 /*
340  *  Tell the user what's going on.
341  */
342 #ifdef NFSROOT_DEBUG
343 static void __init root_nfs_print(void)
344 {
345 	printk(KERN_NOTICE "Root-NFS: Mounting %s on server %s as root\n",
346 		nfs_path, nfs_data.hostname);
347 	printk(KERN_NOTICE "Root-NFS:     rsize = %d, wsize = %d, timeo = %d, retrans = %d\n",
348 		nfs_data.rsize, nfs_data.wsize, nfs_data.timeo, nfs_data.retrans);
349 	printk(KERN_NOTICE "Root-NFS:     acreg (min,max) = (%d,%d), acdir (min,max) = (%d,%d)\n",
350 		nfs_data.acregmin, nfs_data.acregmax,
351 		nfs_data.acdirmin, nfs_data.acdirmax);
352 	printk(KERN_NOTICE "Root-NFS:     nfsd port = %d, mountd port = %d, flags = %08x\n",
353 		nfs_port, mount_port, nfs_data.flags);
354 }
355 #endif
356 
357 
358 static int __init root_nfs_init(void)
359 {
360 #ifdef NFSROOT_DEBUG
361 	nfs_debug |= NFSDBG_ROOT;
362 #endif
363 
364 	/*
365 	 * Decode the root directory path name and NFS options from
366 	 * the kernel command line. This has to go here in order to
367 	 * be able to use the client IP address for the remote root
368 	 * directory (necessary for pure RARP booting).
369 	 */
370 	if (root_nfs_name(nfs_root_name) < 0 ||
371 	    root_nfs_addr() < 0)
372 		return -1;
373 
374 #ifdef NFSROOT_DEBUG
375 	root_nfs_print();
376 #endif
377 
378 	return 0;
379 }
380 
381 
382 /*
383  *  Parse NFS server and directory information passed on the kernel
384  *  command line.
385  */
386 static int __init nfs_root_setup(char *line)
387 {
388 	ROOT_DEV = Root_NFS;
389 	if (line[0] == '/' || line[0] == ',' || (line[0] >= '0' && line[0] <= '9')) {
390 		strlcpy(nfs_root_name, line, sizeof(nfs_root_name));
391 	} else {
392 		int n = strlen(line) + sizeof(NFS_ROOT) - 1;
393 		if (n >= sizeof(nfs_root_name))
394 			line[sizeof(nfs_root_name) - sizeof(NFS_ROOT) - 2] = '\0';
395 		sprintf(nfs_root_name, NFS_ROOT, line);
396 	}
397 	root_server_addr = root_nfs_parse_addr(nfs_root_name);
398 	return 1;
399 }
400 
401 __setup("nfsroot=", nfs_root_setup);
402 
403 /***************************************************************************
404 
405 	       Routines to actually mount the root directory
406 
407  ***************************************************************************/
408 
409 /*
410  *  Construct sockaddr_in from address and port number.
411  */
412 static inline void
413 set_sockaddr(struct sockaddr_in *sin, __u32 addr, __u16 port)
414 {
415 	sin->sin_family = AF_INET;
416 	sin->sin_addr.s_addr = addr;
417 	sin->sin_port = port;
418 }
419 
420 /*
421  *  Query server portmapper for the port of a daemon program.
422  */
423 static int __init root_nfs_getport(int program, int version, int proto)
424 {
425 	struct sockaddr_in sin;
426 
427 	printk(KERN_NOTICE "Looking up port of RPC %d/%d on %u.%u.%u.%u\n",
428 		program, version, NIPQUAD(servaddr));
429 	set_sockaddr(&sin, servaddr, 0);
430 	return rpc_getport_external(&sin, program, version, proto);
431 }
432 
433 
434 /*
435  *  Use portmapper to find mountd and nfsd port numbers if not overriden
436  *  by the user. Use defaults if portmapper is not available.
437  *  XXX: Is there any nfs server with no portmapper?
438  */
439 static int __init root_nfs_ports(void)
440 {
441 	int port;
442 	int nfsd_ver, mountd_ver;
443 	int nfsd_port, mountd_port;
444 	int proto;
445 
446 	if (nfs_data.flags & NFS_MOUNT_VER3) {
447 		nfsd_ver = NFS3_VERSION;
448 		mountd_ver = NFS_MNT3_VERSION;
449 		nfsd_port = NFS_PORT;
450 		mountd_port = NFS_MNT_PORT;
451 	} else {
452 		nfsd_ver = NFS2_VERSION;
453 		mountd_ver = NFS_MNT_VERSION;
454 		nfsd_port = NFS_PORT;
455 		mountd_port = NFS_MNT_PORT;
456 	}
457 
458 	proto = (nfs_data.flags & NFS_MOUNT_TCP) ? IPPROTO_TCP : IPPROTO_UDP;
459 
460 	if (nfs_port < 0) {
461 		if ((port = root_nfs_getport(NFS_PROGRAM, nfsd_ver, proto)) < 0) {
462 			printk(KERN_ERR "Root-NFS: Unable to get nfsd port "
463 					"number from server, using default\n");
464 			port = nfsd_port;
465 		}
466 		nfs_port = htons(port);
467 		dprintk("Root-NFS: Portmapper on server returned %d "
468 			"as nfsd port\n", port);
469 	}
470 
471 	if ((port = root_nfs_getport(NFS_MNT_PROGRAM, mountd_ver, proto)) < 0) {
472 		printk(KERN_ERR "Root-NFS: Unable to get mountd port "
473 				"number from server, using default\n");
474 		port = mountd_port;
475 	}
476 	mount_port = htons(port);
477 	dprintk("Root-NFS: mountd port is %d\n", port);
478 
479 	return 0;
480 }
481 
482 
483 /*
484  *  Get a file handle from the server for the directory which is to be
485  *  mounted.
486  */
487 static int __init root_nfs_get_handle(void)
488 {
489 	struct nfs_fh fh;
490 	struct sockaddr_in sin;
491 	int status;
492 	int protocol = (nfs_data.flags & NFS_MOUNT_TCP) ?
493 					IPPROTO_TCP : IPPROTO_UDP;
494 	int version = (nfs_data.flags & NFS_MOUNT_VER3) ?
495 					NFS_MNT3_VERSION : NFS_MNT_VERSION;
496 
497 	set_sockaddr(&sin, servaddr, mount_port);
498 	status = nfsroot_mount(&sin, nfs_path, &fh, version, protocol);
499 	if (status < 0)
500 		printk(KERN_ERR "Root-NFS: Server returned error %d "
501 				"while mounting %s\n", status, nfs_path);
502 	else {
503 		nfs_data.root.size = fh.size;
504 		memcpy(nfs_data.root.data, fh.data, fh.size);
505 	}
506 
507 	return status;
508 }
509 
510 /*
511  *  Get the NFS port numbers and file handle, and return the prepared 'data'
512  *  argument for mount() if everything went OK. Return NULL otherwise.
513  */
514 void * __init nfs_root_data(void)
515 {
516 	if (root_nfs_init() < 0
517 	 || root_nfs_ports() < 0
518 	 || root_nfs_get_handle() < 0)
519 		return NULL;
520 	set_sockaddr((struct sockaddr_in *) &nfs_data.addr, servaddr, nfs_port);
521 	return (void*)&nfs_data;
522 }
523