blob: 903908a20023bf83b08d7fc6c808cbd4f20e0aa2 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 * 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.
Chuck Lever56463e52010-09-17 10:54:37 -04006 * (2) Construct the device string and the options string using DHCP
7 * option 17 and/or kernel command line options.
8 * (3) When mount_root() sets up the root file system, pass these strings
9 * to the NFS client's regular mount interface via sys_mount().
Linus Torvalds1da177e2005-04-16 15:20:36 -070010 *
11 *
12 * Changes:
13 *
14 * Alan Cox : Removed get_address name clash with FPU.
15 * Alan Cox : Reformatted a bit.
16 * Gero Kuhlmann : Code cleanup
17 * Michael Rausch : Fixed recognition of an incoming RARP answer.
18 * Martin Mares : (2.0) Auto-configuration via BOOTP supported.
19 * Martin Mares : Manual selection of interface & BOOTP/RARP.
20 * Martin Mares : Using network routes instead of host routes,
21 * allowing the default configuration to be used
22 * for normal operation of the host.
23 * Martin Mares : Randomized timer with exponential backoff
24 * installed to minimize network congestion.
25 * Martin Mares : Code cleanup.
26 * Martin Mares : (2.1) BOOTP and RARP made configuration options.
27 * Martin Mares : Server hostname generation fixed.
28 * Gerd Knorr : Fixed wired inode handling
29 * Martin Mares : (2.2) "0.0.0.0" addresses from command line ignored.
30 * Martin Mares : RARP replies not tested for server address.
31 * Gero Kuhlmann : (2.3) Some bug fixes and code cleanup again (please
32 * send me your new patches _before_ bothering
33 * Linus so that I don' always have to cleanup
34 * _afterwards_ - thanks)
35 * Gero Kuhlmann : Last changes of Martin Mares undone.
36 * Gero Kuhlmann : RARP replies are tested for specified server
37 * again. However, it's now possible to have
38 * different RARP and NFS servers.
39 * Gero Kuhlmann : "0.0.0.0" addresses from command line are
40 * now mapped to INADDR_NONE.
41 * Gero Kuhlmann : Fixed a bug which prevented BOOTP path name
42 * from being used (thanks to Leo Spiekman)
43 * Andy Walker : Allow to specify the NFS server in nfs_root
44 * without giving a path name
Jan Engelhardt96de0e22007-10-19 23:21:04 +020045 * Swen Thümmler : Allow to specify the NFS options in nfs_root
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 * without giving a path name. Fix BOOTP request
47 * for domainname (domainname is NIS domain, not
48 * DNS domain!). Skip dummy devices for BOOTP.
49 * Jacek Zapala : Fixed a bug which prevented server-ip address
50 * from nfsroot parameter from being used.
51 * Olaf Kirch : Adapted to new NFS code.
52 * Jakub Jelinek : Free used code segment.
53 * Marko Kohtala : Fixed some bugs.
54 * Martin Mares : Debug message cleanup
55 * Martin Mares : Changed to use the new generic IP layer autoconfig
56 * code. BOOTP and RARP moved there.
57 * Martin Mares : Default path now contains host name instead of
58 * host IP address (but host name defaults to IP
59 * address anyway).
60 * Martin Mares : Use root_server_addr appropriately during setup.
61 * Martin Mares : Rewrote parameter parsing, now hopefully giving
62 * correct overriding.
63 * Trond Myklebust : Add in preliminary support for NFSv3 and TCP.
64 * Fix bug in root_nfs_addr(). nfs_data.namlen
65 * is NOT for the length of the hostname.
66 * Hua Qin : Support for mounting root file system via
67 * NFS over TCP.
68 * Fabian Frederick: Option parser rebuilt (using parser lib)
Chuck Lever56463e52010-09-17 10:54:37 -040069 * Chuck Lever : Use super.c's text-based mount option parsing
Chuck Lever306a0752010-09-17 10:54:37 -040070 * Chuck Lever : Add "nfsrootdebug".
Chuck Lever56463e52010-09-17 10:54:37 -040071 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070072
Linus Torvalds1da177e2005-04-16 15:20:36 -070073#include <linux/types.h>
74#include <linux/string.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070075#include <linux/init.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070076#include <linux/nfs.h>
77#include <linux/nfs_fs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070078#include <linux/utsname.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070079#include <linux/root_dev.h>
80#include <net/ipconfig.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070081
Chuck Lever146ec942008-12-23 15:21:34 -050082#include "internal.h"
83
Linus Torvalds1da177e2005-04-16 15:20:36 -070084#define NFSDBG_FACILITY NFSDBG_ROOT
85
86/* Default path we try to mount. "%s" gets replaced by our IP address */
87#define NFS_ROOT "/tftpboot/%s"
88
89/* Parameters passed from the kernel command line */
Chuck Lever60ac0362010-09-17 10:54:37 -040090static char nfs_root_parms[256] __initdata = "";
Linus Torvalds1da177e2005-04-16 15:20:36 -070091
Chuck Lever56463e52010-09-17 10:54:37 -040092/* Text-based mount options passed to super.c */
93static char nfs_root_options[256] __initdata = "";
94
Linus Torvalds1da177e2005-04-16 15:20:36 -070095/* Address of NFS server */
Chuck Lever8d232102010-09-17 10:54:37 -040096static __be32 servaddr __initdata = htonl(INADDR_NONE);
Linus Torvalds1da177e2005-04-16 15:20:36 -070097
98/* Name of directory to mount */
Chuck Lever56463e52010-09-17 10:54:37 -040099static char nfs_export_path[NFS_MAXPATHLEN + 1] __initdata = "";
100
101/* server:export path string passed to super.c */
102static char nfs_root_device[NFS_MAXPATHLEN + 1] __initdata = "";
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103
Trond Myklebust036a1072010-10-26 13:47:04 -0400104#ifdef RPC_DEBUG
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105/*
Chuck Lever306a0752010-09-17 10:54:37 -0400106 * When the "nfsrootdebug" kernel command line option is specified,
107 * enable debugging messages for NFSROOT.
108 */
109static int __init nfs_root_debug(char *__unused)
110{
111 nfs_debug |= NFSDBG_ROOT | NFSDBG_MOUNT;
112 return 1;
113}
114
115__setup("nfsrootdebug", nfs_root_debug);
Trond Myklebust036a1072010-10-26 13:47:04 -0400116#endif
Chuck Lever306a0752010-09-17 10:54:37 -0400117
118/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 * Parse NFS server and directory information passed on the kernel
120 * command line.
Chuck Lever60ac0362010-09-17 10:54:37 -0400121 *
122 * nfsroot=[<server-ip>:]<root-dir>[,<nfs-options>]
123 *
124 * If there is a "%s" token in the <root-dir> string, it is replaced
125 * by the ASCII-representation of the client's IP address.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 */
127static int __init nfs_root_setup(char *line)
128{
129 ROOT_DEV = Root_NFS;
Chuck Lever60ac0362010-09-17 10:54:37 -0400130
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 if (line[0] == '/' || line[0] == ',' || (line[0] >= '0' && line[0] <= '9')) {
Chuck Lever60ac0362010-09-17 10:54:37 -0400132 strlcpy(nfs_root_parms, line, sizeof(nfs_root_parms));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 } else {
Chuck Lever60ac0362010-09-17 10:54:37 -0400134 size_t n = strlen(line) + sizeof(NFS_ROOT) - 1;
135 if (n >= sizeof(nfs_root_parms))
136 line[sizeof(nfs_root_parms) - sizeof(NFS_ROOT) - 2] = '\0';
137 sprintf(nfs_root_parms, NFS_ROOT, line);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 }
Chuck Lever60ac0362010-09-17 10:54:37 -0400139
140 /*
141 * Extract the IP address of the NFS server containing our
142 * root file system, if one was specified.
143 *
144 * Note: root_nfs_parse_addr() removes the server-ip from
145 * nfs_root_parms, if it exists.
146 */
147 root_server_addr = root_nfs_parse_addr(nfs_root_parms);
148
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 return 1;
150}
151
152__setup("nfsroot=", nfs_root_setup);
153
Chuck Lever56463e52010-09-17 10:54:37 -0400154static int __init root_nfs_copy(char *dest, const char *src,
155 const size_t destlen)
156{
157 if (strlcpy(dest, src, destlen) > destlen)
158 return -1;
159 return 0;
160}
161
162static int __init root_nfs_cat(char *dest, const char *src,
163 const size_t destlen)
164{
165 if (strlcat(dest, src, destlen) > destlen)
166 return -1;
167 return 0;
168}
169
170/*
171 * Parse out root export path and mount options from
172 * passed-in string @incoming.
173 *
174 * Copy the export path into @exppath.
175 */
176static int __init root_nfs_parse_options(char *incoming, char *exppath,
177 const size_t exppathlen)
178{
179 char *p;
180
181 /*
182 * Set the NFS remote path
183 */
184 p = strsep(&incoming, ",");
185 if (*p != '\0' && strcmp(p, "default") != 0)
186 if (root_nfs_copy(exppath, p, exppathlen))
187 return -1;
188
189 /*
190 * @incoming now points to the rest of the string; if it
191 * contains something, append it to our root options buffer
192 */
193 if (incoming != NULL && *incoming != '\0')
194 if (root_nfs_cat(nfs_root_options, incoming,
195 sizeof(nfs_root_options)))
196 return -1;
197
198 /*
199 * Possibly prepare for more options to be appended
200 */
201 if (nfs_root_options[0] != '\0' &&
202 nfs_root_options[strlen(nfs_root_options)] != ',')
203 if (root_nfs_cat(nfs_root_options, ",",
204 sizeof(nfs_root_options)))
205 return -1;
206
207 return 0;
208}
209
210/*
211 * Decode the export directory path name and NFS options from
212 * the kernel command line. This has to be done late in order to
213 * use a dynamically acquired client IP address for the remote
214 * root directory path.
215 *
216 * Returns zero if successful; otherwise -1 is returned.
217 */
218static int __init root_nfs_data(char *cmdline)
219{
220 char addr_option[sizeof("nolock,addr=") + INET_ADDRSTRLEN + 1];
221 int len, retval = -1;
222 char *tmp = NULL;
223 const size_t tmplen = sizeof(nfs_export_path);
224
225 tmp = kzalloc(tmplen, GFP_KERNEL);
226 if (tmp == NULL)
227 goto out_nomem;
228 strcpy(tmp, NFS_ROOT);
229
230 if (root_server_path[0] != '\0') {
231 dprintk("Root-NFS: DHCPv4 option 17: %s\n",
232 root_server_path);
233 if (root_nfs_parse_options(root_server_path, tmp, tmplen))
234 goto out_optionstoolong;
235 }
236
237 if (cmdline[0] != '\0') {
238 dprintk("Root-NFS: nfsroot=%s\n", cmdline);
239 if (root_nfs_parse_options(cmdline, tmp, tmplen))
240 goto out_optionstoolong;
241 }
242
243 /*
244 * Append mandatory options for nfsroot so they override
245 * what has come before
246 */
247 snprintf(addr_option, sizeof(addr_option), "nolock,addr=%pI4",
248 &servaddr);
249 if (root_nfs_cat(nfs_root_options, addr_option,
250 sizeof(nfs_root_options)))
251 goto out_optionstoolong;
252
253 /*
254 * Set up nfs_root_device. For NFS mounts, this looks like
255 *
256 * server:/path
257 *
258 * At this point, utsname()->nodename contains our local
259 * IP address or hostname, set by ipconfig. If "%s" exists
260 * in tmp, substitute the nodename, then shovel the whole
261 * mess into nfs_root_device.
262 */
263 len = snprintf(nfs_export_path, sizeof(nfs_export_path),
264 tmp, utsname()->nodename);
265 if (len > (int)sizeof(nfs_export_path))
266 goto out_devnametoolong;
267 len = snprintf(nfs_root_device, sizeof(nfs_root_device),
268 "%pI4:%s", &servaddr, nfs_export_path);
269 if (len > (int)sizeof(nfs_root_device))
270 goto out_devnametoolong;
271
272 retval = 0;
273
274out:
275 kfree(tmp);
276 return retval;
277out_nomem:
278 printk(KERN_ERR "Root-NFS: could not allocate memory\n");
279 goto out;
280out_optionstoolong:
281 printk(KERN_ERR "Root-NFS: mount options string too long\n");
282 goto out;
283out_devnametoolong:
284 printk(KERN_ERR "Root-NFS: root device name too long.\n");
285 goto out;
286}
287
288/**
289 * nfs_root_data - Return prepared 'data' for NFSROOT mount
290 * @root_device: OUT: address of string containing NFSROOT device
291 * @root_data: OUT: address of string containing NFSROOT mount options
292 *
293 * Returns zero and sets @root_device and @root_data if successful,
294 * otherwise -1 is returned.
295 */
296int __init nfs_root_data(char **root_device, char **root_data)
297{
Chuck Lever56463e52010-09-17 10:54:37 -0400298 servaddr = root_server_addr;
299 if (servaddr == htonl(INADDR_NONE)) {
300 printk(KERN_ERR "Root-NFS: no NFS server address\n");
301 return -1;
302 }
303
304 if (root_nfs_data(nfs_root_parms) < 0)
305 return -1;
306
307 *root_device = nfs_root_device;
308 *root_data = nfs_root_options;
309 return 0;
310}