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 : Finish support for mounting root file system
68 * via NFS over TCP.
69 */
70
71 #include <linux/config.h>
72 #include <linux/types.h>
73 #include <linux/string.h>
74 #include <linux/kernel.h>
75 #include <linux/sched.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 <net/ipconfig.h>
86
87 /* Define this to allow debugging output */
88 #undef NFSROOT_DEBUG
89 #define NFSDBG_FACILITY NFSDBG_ROOT
90
91 /* Default path we try to mount. "%s" gets replaced by our IP address */
92 #define NFS_ROOT "/tftpboot/%s"
93
94 /* Parameters passed from the kernel command line */
95 static char nfs_root_name[256] __initdata = "";
96
97 /* Address of NFS server */
98 static __u32 servaddr __initdata = 0;
99
100 /* Name of directory to mount */
101 static char nfs_path[NFS_MAXPATHLEN] __initdata = { 0, };
102
103 /* NFS-related data */
104 static struct nfs_mount_data nfs_data __initdata = { 0, };/* NFS mount info */
105 static int nfs_port __initdata = 0; /* Port to connect to for NFS */
106 static int mount_port __initdata = 0; /* Mount daemon port number */
107
108
109 /***************************************************************************
110
111 Parsing of options
112
113 ***************************************************************************/
114
115 /*
116 * The following integer options are recognized
117 */
118 static struct nfs_int_opts {
119 char *name;
120 int *val;
121 } root_int_opts[] __initdata = {
122 { "port", &nfs_port },
123 { "rsize", &nfs_data.rsize },
124 { "wsize", &nfs_data.wsize },
125 { "timeo", &nfs_data.timeo },
126 { "retrans", &nfs_data.retrans },
127 { "acregmin", &nfs_data.acregmin },
128 { "acregmax", &nfs_data.acregmax },
129 { "acdirmin", &nfs_data.acdirmin },
130 { "acdirmax", &nfs_data.acdirmax },
131 { NULL, NULL }
132 };
133
134
135 /*
136 * And now the flag options
137 */
138 static struct nfs_bool_opts {
139 char *name;
140 int and_mask;
141 int or_mask;
142 } root_bool_opts[] __initdata = {
143 { "soft", ~NFS_MOUNT_SOFT, NFS_MOUNT_SOFT },
144 { "hard", ~NFS_MOUNT_SOFT, 0 },
145 { "intr", ~NFS_MOUNT_INTR, NFS_MOUNT_INTR },
146 { "nointr", ~NFS_MOUNT_INTR, 0 },
147 { "posix", ~NFS_MOUNT_POSIX, NFS_MOUNT_POSIX },
148 { "noposix", ~NFS_MOUNT_POSIX, 0 },
149 { "cto", ~NFS_MOUNT_NOCTO, 0 },
150 { "nocto", ~NFS_MOUNT_NOCTO, NFS_MOUNT_NOCTO },
151 { "ac", ~NFS_MOUNT_NOAC, 0 },
152 { "noac", ~NFS_MOUNT_NOAC, NFS_MOUNT_NOAC },
153 { "lock", ~NFS_MOUNT_NONLM, 0 },
154 { "nolock", ~NFS_MOUNT_NONLM, NFS_MOUNT_NONLM },
155 #ifdef CONFIG_NFS_V3
156 { "v2", ~NFS_MOUNT_VER3, 0 },
157 { "v3", ~NFS_MOUNT_VER3, NFS_MOUNT_VER3 },
158 #endif
159 { "udp", ~NFS_MOUNT_TCP, 0 },
160 { "tcp", ~NFS_MOUNT_TCP, NFS_MOUNT_TCP },
161 { "broken_suid",~NFS_MOUNT_BROKEN_SUID, NFS_MOUNT_BROKEN_SUID },
162 { NULL, 0, 0 }
163 };
164
165
166 /*
167 * Parse option string.
168 */
root_nfs_parse(char * name,char * buf)169 static void __init root_nfs_parse(char *name, char *buf)
170 {
171 char *options, *val, *cp;
172
173 if ((options = strchr(name, ','))) {
174 *options++ = 0;
175 cp = strtok(options, ",");
176 while (cp) {
177 if ((val = strchr(cp, '='))) {
178 struct nfs_int_opts *opts = root_int_opts;
179 *val++ = '\0';
180 while (opts->name && strcmp(opts->name, cp))
181 opts++;
182 if (opts->name)
183 *(opts->val) = (int) simple_strtoul(val, NULL, 10);
184 } else {
185 struct nfs_bool_opts *opts = root_bool_opts;
186 while (opts->name && strcmp(opts->name, cp))
187 opts++;
188 if (opts->name) {
189 nfs_data.flags &= opts->and_mask;
190 nfs_data.flags |= opts->or_mask;
191 }
192 }
193 cp = strtok(NULL, ",");
194 }
195 }
196 if (name[0] && strcmp(name, "default")) {
197 strncpy(buf, name, NFS_MAXPATHLEN-1);
198 buf[NFS_MAXPATHLEN-1] = 0;
199 }
200 }
201
202
203 /*
204 * Prepare the NFS data structure and parse all options.
205 */
root_nfs_name(char * name)206 static int __init root_nfs_name(char *name)
207 {
208 char buf[NFS_MAXPATHLEN];
209 char *cp;
210
211 /* Set some default values */
212 memset(&nfs_data, 0, sizeof(nfs_data));
213 nfs_port = -1;
214 nfs_data.version = NFS_MOUNT_VERSION;
215 nfs_data.flags = NFS_MOUNT_NONLM; /* No lockd in nfs root yet */
216 nfs_data.rsize = NFS_DEF_FILE_IO_BUFFER_SIZE;
217 nfs_data.wsize = NFS_DEF_FILE_IO_BUFFER_SIZE;
218 nfs_data.bsize = 0;
219 nfs_data.timeo = 7;
220 nfs_data.retrans = 3;
221 nfs_data.acregmin = 3;
222 nfs_data.acregmax = 60;
223 nfs_data.acdirmin = 30;
224 nfs_data.acdirmax = 60;
225 strcpy(buf, NFS_ROOT);
226
227 /* Process options received from the remote server */
228 root_nfs_parse(root_server_path, buf);
229
230 /* Override them by options set on kernel command-line */
231 root_nfs_parse(name, buf);
232
233 cp = system_utsname.nodename;
234 if (strlen(buf) + strlen(cp) > NFS_MAXPATHLEN) {
235 printk(KERN_ERR "Root-NFS: Pathname for remote directory too long.\n");
236 return -1;
237 }
238 sprintf(nfs_path, buf, cp);
239
240 return 1;
241 }
242
243
244 /*
245 * Get NFS server address.
246 */
root_nfs_addr(void)247 static int __init root_nfs_addr(void)
248 {
249 if ((servaddr = root_server_addr) == INADDR_NONE) {
250 printk(KERN_ERR "Root-NFS: No NFS server available, giving up.\n");
251 return -1;
252 }
253
254 snprintf(nfs_data.hostname, sizeof(nfs_data.hostname),
255 "%u.%u.%u.%u", NIPQUAD(servaddr));
256 return 0;
257 }
258
259 /*
260 * Tell the user what's going on.
261 */
262 #ifdef NFSROOT_DEBUG
root_nfs_print(void)263 static void __init root_nfs_print(void)
264 {
265 printk(KERN_NOTICE "Root-NFS: Mounting %s on server %s as root\n",
266 nfs_path, nfs_data.hostname);
267 printk(KERN_NOTICE "Root-NFS: rsize = %d, wsize = %d, timeo = %d, retrans = %d\n",
268 nfs_data.rsize, nfs_data.wsize, nfs_data.timeo, nfs_data.retrans);
269 printk(KERN_NOTICE "Root-NFS: acreg (min,max) = (%d,%d), acdir (min,max) = (%d,%d)\n",
270 nfs_data.acregmin, nfs_data.acregmax,
271 nfs_data.acdirmin, nfs_data.acdirmax);
272 printk(KERN_NOTICE "Root-NFS: nfsd port = %d, mountd port = %d, flags = %08x\n",
273 nfs_port, mount_port, nfs_data.flags);
274 }
275 #endif
276
277
root_nfs_init(void)278 int __init root_nfs_init(void)
279 {
280 #ifdef NFSROOT_DEBUG
281 nfs_debug |= NFSDBG_ROOT;
282 #endif
283
284 /*
285 * Decode the root directory path name and NFS options from
286 * the kernel command line. This has to go here in order to
287 * be able to use the client IP address for the remote root
288 * directory (necessary for pure RARP booting).
289 */
290 if (root_nfs_name(nfs_root_name) < 0 ||
291 root_nfs_addr() < 0)
292 return -1;
293
294 #ifdef NFSROOT_DEBUG
295 root_nfs_print();
296 #endif
297
298 return 0;
299 }
300
301
302 /*
303 * Parse NFS server and directory information passed on the kernel
304 * command line.
305 */
nfs_root_setup(char * line)306 int __init nfs_root_setup(char *line)
307 {
308 ROOT_DEV = MKDEV(NFS_MAJOR, NFS_MINOR);
309 if (line[0] == '/' || line[0] == ',' || (line[0] >= '0' && line[0] <= '9')) {
310 strncpy(nfs_root_name, line, sizeof(nfs_root_name));
311 nfs_root_name[sizeof(nfs_root_name)-1] = '\0';
312 } else {
313 int n = strlen(line) + strlen(NFS_ROOT);
314 if (n >= sizeof(nfs_root_name))
315 line[sizeof(nfs_root_name) - strlen(NFS_ROOT) - 1] = '\0';
316 sprintf(nfs_root_name, NFS_ROOT, line);
317 }
318 root_server_addr = root_nfs_parse_addr(nfs_root_name);
319 return 1;
320 }
321
322 __setup("nfsroot=", nfs_root_setup);
323
324 /***************************************************************************
325
326 Routines to actually mount the root directory
327
328 ***************************************************************************/
329
330 /*
331 * Construct sockaddr_in from address and port number.
332 */
333 static inline void
set_sockaddr(struct sockaddr_in * sin,__u32 addr,__u16 port)334 set_sockaddr(struct sockaddr_in *sin, __u32 addr, __u16 port)
335 {
336 sin->sin_family = AF_INET;
337 sin->sin_addr.s_addr = addr;
338 sin->sin_port = port;
339 }
340
341 /*
342 * Query server portmapper for the port of a daemon program.
343 */
root_nfs_getport(int program,int version,int proto)344 static int __init root_nfs_getport(int program, int version, int proto)
345 {
346 struct sockaddr_in sin;
347
348 printk(KERN_NOTICE "Looking up port of RPC %d/%d on %u.%u.%u.%u\n",
349 program, version, NIPQUAD(servaddr));
350 set_sockaddr(&sin, servaddr, 0);
351 return rpc_getport_external(&sin, program, version, proto);
352 }
353
354
355 /*
356 * Use portmapper to find mountd and nfsd port numbers if not overriden
357 * by the user. Use defaults if portmapper is not available.
358 * XXX: Is there any nfs server with no portmapper?
359 */
root_nfs_ports(void)360 static int __init root_nfs_ports(void)
361 {
362 int port;
363 int nfsd_ver, mountd_ver;
364 int nfsd_port, mountd_port;
365 int proto;
366
367 if (nfs_data.flags & NFS_MOUNT_VER3) {
368 nfsd_ver = NFS3_VERSION;
369 mountd_ver = NFS_MNT3_VERSION;
370 nfsd_port = NFS_PORT;
371 mountd_port = NFS_MNT_PORT;
372 } else {
373 nfsd_ver = NFS2_VERSION;
374 mountd_ver = NFS_MNT_VERSION;
375 nfsd_port = NFS_PORT;
376 mountd_port = NFS_MNT_PORT;
377 }
378
379 proto = (nfs_data.flags & NFS_MOUNT_TCP) ? IPPROTO_TCP : IPPROTO_UDP;
380
381 if (nfs_port < 0) {
382 if ((port = root_nfs_getport(NFS_PROGRAM, nfsd_ver, proto)) < 0) {
383 printk(KERN_ERR "Root-NFS: Unable to get nfsd port "
384 "number from server, using default\n");
385 port = nfsd_port;
386 }
387 nfs_port = port;
388 dprintk("Root-NFS: Portmapper on server returned %d "
389 "as nfsd port\n", port);
390 }
391 nfs_port = htons(nfs_port);
392
393 if ((port = root_nfs_getport(NFS_MNT_PROGRAM, mountd_ver, proto)) < 0) {
394 printk(KERN_ERR "Root-NFS: Unable to get mountd port "
395 "number from server, using default\n");
396 port = mountd_port;
397 }
398 mount_port = htons(port);
399 dprintk("Root-NFS: mountd port is %d\n", port);
400
401 return 0;
402 }
403
404
405 /*
406 * Get a file handle from the server for the directory which is to be
407 * mounted.
408 */
root_nfs_get_handle(void)409 static int __init root_nfs_get_handle(void)
410 {
411 struct sockaddr_in sin;
412 int status;
413 int protocol = (nfs_data.flags & NFS_MOUNT_TCP) ?
414 IPPROTO_TCP : IPPROTO_UDP;
415 int version = (nfs_data.flags & NFS_MOUNT_VER3) ?
416 NFS_MNT3_VERSION : NFS_MNT_VERSION;
417
418 set_sockaddr(&sin, servaddr, mount_port);
419 status = nfsroot_mount(&sin, nfs_path, &nfs_data.root,
420 version, protocol);
421 if (status < 0)
422 printk(KERN_ERR "Root-NFS: Server returned error %d "
423 "while mounting %s\n", status, nfs_path);
424
425 return status;
426 }
427
428 /*
429 * Get the NFS port numbers and file handle, and return the prepared 'data'
430 * argument for ->read_super() if everything went OK. Return NULL otherwise.
431 */
nfs_root_data(void)432 void * __init nfs_root_data(void)
433 {
434 if (root_nfs_init() < 0
435 || root_nfs_ports() < 0
436 || root_nfs_get_handle() < 0)
437 return NULL;
438 set_sockaddr((struct sockaddr_in *) &nfs_data.addr, servaddr, nfs_port);
439 return (void*)&nfs_data;
440 }
441