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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) 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().
10 *
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
45 * Swen Thümmler : Allow to specify the NFS options in nfs_root
46 * 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)
69 * Chuck Lever : Use super.c's text-based mount option parsing
70 * Chuck Lever : Add "nfsrootdebug".
71 */
72
73#include <linux/types.h>
74#include <linux/string.h>
75#include <linux/init.h>
76#include <linux/nfs.h>
77#include <linux/nfs_fs.h>
78#include <linux/utsname.h>
79#include <linux/root_dev.h>
80#include <net/ipconfig.h>
81
82#include "internal.h"
83
84#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/* Default NFSROOT mount options. */
90#define NFS_DEF_OPTIONS "vers=2,udp,rsize=4096,wsize=4096"
91
92/* Parameters passed from the kernel command line */
93static char nfs_root_parms[NFS_MAXPATHLEN + 1] __initdata = "";
94
95/* Text-based mount options passed to super.c */
96static char nfs_root_options[256] __initdata = NFS_DEF_OPTIONS;
97
98/* Address of NFS server */
99static __be32 servaddr __initdata = htonl(INADDR_NONE);
100
101/* Name of directory to mount */
102static char nfs_export_path[NFS_MAXPATHLEN + 1] __initdata = "";
103
104/* server:export path string passed to super.c */
105static char nfs_root_device[NFS_MAXPATHLEN + 1] __initdata = "";
106
107#ifdef NFS_DEBUG
108/*
109 * When the "nfsrootdebug" kernel command line option is specified,
110 * enable debugging messages for NFSROOT.
111 */
112static int __init nfs_root_debug(char *__unused)
113{
114 nfs_debug |= NFSDBG_ROOT | NFSDBG_MOUNT;
115 return 1;
116}
117
118__setup("nfsrootdebug", nfs_root_debug);
119#endif
120
121/*
122 * Parse NFS server and directory information passed on the kernel
123 * command line.
124 *
125 * nfsroot=[<server-ip>:]<root-dir>[,<nfs-options>]
126 *
127 * If there is a "%s" token in the <root-dir> string, it is replaced
128 * by the ASCII-representation of the client's IP address.
129 */
130static int __init nfs_root_setup(char *line)
131{
132 ROOT_DEV = Root_NFS;
133
134 if (line[0] == '/' || line[0] == ',' || (line[0] >= '0' && line[0] <= '9')) {
135 strlcpy(nfs_root_parms, line, sizeof(nfs_root_parms));
136 } else {
137 size_t n = strlen(line) + sizeof(NFS_ROOT) - 1;
138 if (n >= sizeof(nfs_root_parms))
139 line[sizeof(nfs_root_parms) - sizeof(NFS_ROOT) - 2] = '\0';
140 sprintf(nfs_root_parms, NFS_ROOT, line);
141 }
142
143 /*
144 * Extract the IP address of the NFS server containing our
145 * root file system, if one was specified.
146 *
147 * Note: root_nfs_parse_addr() removes the server-ip from
148 * nfs_root_parms, if it exists.
149 */
150 root_server_addr = root_nfs_parse_addr(nfs_root_parms);
151
152 return 1;
153}
154
155__setup("nfsroot=", nfs_root_setup);
156
157static int __init root_nfs_copy(char *dest, const char *src,
158 const size_t destlen)
159{
160 if (strlcpy(dest, src, destlen) > destlen)
161 return -1;
162 return 0;
163}
164
165static int __init root_nfs_cat(char *dest, const char *src,
166 const size_t destlen)
167{
168 size_t len = strlen(dest);
169
170 if (len && dest[len - 1] != ',')
171 if (strlcat(dest, ",", destlen) > destlen)
172 return -1;
173
174 if (strlcat(dest, src, destlen) > destlen)
175 return -1;
176 return 0;
177}
178
179/*
180 * Parse out root export path and mount options from
181 * passed-in string @incoming.
182 *
183 * Copy the export path into @exppath.
184 */
185static int __init root_nfs_parse_options(char *incoming, char *exppath,
186 const size_t exppathlen)
187{
188 char *p;
189
190 /*
191 * Set the NFS remote path
192 */
193 p = strsep(&incoming, ",");
194 if (*p != '\0' && strcmp(p, "default") != 0)
195 if (root_nfs_copy(exppath, p, exppathlen))
196 return -1;
197
198 /*
199 * @incoming now points to the rest of the string; if it
200 * contains something, append it to our root options buffer
201 */
202 if (incoming != NULL && *incoming != '\0')
203 if (root_nfs_cat(nfs_root_options, incoming,
204 sizeof(nfs_root_options)))
205 return -1;
206 return 0;
207}
208
209/*
210 * Decode the export directory path name and NFS options from
211 * the kernel command line. This has to be done late in order to
212 * use a dynamically acquired client IP address for the remote
213 * root directory path.
214 *
215 * Returns zero if successful; otherwise -1 is returned.
216 */
217static int __init root_nfs_data(char *cmdline)
218{
219 char mand_options[sizeof("nolock,addr=") + INET_ADDRSTRLEN + 1];
220 int len, retval = -1;
221 char *tmp = NULL;
222 const size_t tmplen = sizeof(nfs_export_path);
223
224 tmp = kzalloc(tmplen, GFP_KERNEL);
225 if (tmp == NULL)
226 goto out_nomem;
227 strcpy(tmp, NFS_ROOT);
228
229 if (root_server_path[0] != '\0') {
230 dprintk("Root-NFS: DHCPv4 option 17: %s\n",
231 root_server_path);
232 if (root_nfs_parse_options(root_server_path, tmp, tmplen))
233 goto out_optionstoolong;
234 }
235
236 if (cmdline[0] != '\0') {
237 dprintk("Root-NFS: nfsroot=%s\n", cmdline);
238 if (root_nfs_parse_options(cmdline, tmp, tmplen))
239 goto out_optionstoolong;
240 }
241
242 /*
243 * Append mandatory options for nfsroot so they override
244 * what has come before
245 */
246 snprintf(mand_options, sizeof(mand_options), "nolock,addr=%pI4",
247 &servaddr);
248 if (root_nfs_cat(nfs_root_options, mand_options,
249 sizeof(nfs_root_options)))
250 goto out_optionstoolong;
251
252 /*
253 * Set up nfs_root_device. For NFS mounts, this looks like
254 *
255 * server:/path
256 *
257 * At this point, utsname()->nodename contains our local
258 * IP address or hostname, set by ipconfig. If "%s" exists
259 * in tmp, substitute the nodename, then shovel the whole
260 * mess into nfs_root_device.
261 */
262 len = snprintf(nfs_export_path, sizeof(nfs_export_path),
263 tmp, utsname()->nodename);
264 if (len >= (int)sizeof(nfs_export_path))
265 goto out_devnametoolong;
266 len = snprintf(nfs_root_device, sizeof(nfs_root_device),
267 "%pI4:%s", &servaddr, nfs_export_path);
268 if (len >= (int)sizeof(nfs_root_device))
269 goto out_devnametoolong;
270
271 retval = 0;
272
273out:
274 kfree(tmp);
275 return retval;
276out_nomem:
277 printk(KERN_ERR "Root-NFS: could not allocate memory\n");
278 goto out;
279out_optionstoolong:
280 printk(KERN_ERR "Root-NFS: mount options string too long\n");
281 goto out;
282out_devnametoolong:
283 printk(KERN_ERR "Root-NFS: root device name too long.\n");
284 goto out;
285}
286
287/**
288 * nfs_root_data - Return prepared 'data' for NFSROOT mount
289 * @root_device: OUT: address of string containing NFSROOT device
290 * @root_data: OUT: address of string containing NFSROOT mount options
291 *
292 * Returns zero and sets @root_device and @root_data if successful,
293 * otherwise -1 is returned.
294 */
295int __init nfs_root_data(char **root_device, char **root_data)
296{
297 servaddr = root_server_addr;
298 if (servaddr == htonl(INADDR_NONE)) {
299 printk(KERN_ERR "Root-NFS: no NFS server address\n");
300 return -1;
301 }
302
303 if (root_nfs_data(nfs_root_parms) < 0)
304 return -1;
305
306 *root_device = nfs_root_device;
307 *root_data = nfs_root_options;
308 return 0;
309}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 1995, 1996 Gero Kuhlmann <gero@gkminix.han.de>
4 *
5 * Allow an NFS filesystem to be mounted as root. The way this works is:
6 * (1) Use the IP autoconfig mechanism to set local IP addresses and routes.
7 * (2) Construct the device string and the options string using DHCP
8 * option 17 and/or kernel command line options.
9 * (3) When mount_root() sets up the root file system, pass these strings
10 * to the NFS client's regular mount interface via sys_mount().
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 Thümmler : 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 * Chuck Lever : Use super.c's text-based mount option parsing
71 * Chuck Lever : Add "nfsrootdebug".
72 */
73
74#include <linux/types.h>
75#include <linux/string.h>
76#include <linux/init.h>
77#include <linux/nfs.h>
78#include <linux/nfs_fs.h>
79#include <linux/utsname.h>
80#include <linux/root_dev.h>
81#include <net/ipconfig.h>
82
83#include "internal.h"
84
85#define NFSDBG_FACILITY NFSDBG_ROOT
86
87/* Default path we try to mount. "%s" gets replaced by our IP address */
88#define NFS_ROOT "/tftpboot/%s"
89
90/* Default NFSROOT mount options. */
91#define NFS_DEF_OPTIONS "vers=2,tcp,rsize=4096,wsize=4096"
92
93/* Parameters passed from the kernel command line */
94static char nfs_root_parms[NFS_MAXPATHLEN + 1] __initdata = "";
95
96/* Text-based mount options passed to super.c */
97static char nfs_root_options[256] __initdata = NFS_DEF_OPTIONS;
98
99/* Address of NFS server */
100static __be32 servaddr __initdata = htonl(INADDR_NONE);
101
102/* Name of directory to mount */
103static char nfs_export_path[NFS_MAXPATHLEN + 1] __initdata = "";
104
105/* server:export path string passed to super.c */
106static char nfs_root_device[NFS_MAXPATHLEN + 1] __initdata = "";
107
108#ifdef NFS_DEBUG
109/*
110 * When the "nfsrootdebug" kernel command line option is specified,
111 * enable debugging messages for NFSROOT.
112 */
113static int __init nfs_root_debug(char *__unused)
114{
115 nfs_debug |= NFSDBG_ROOT | NFSDBG_MOUNT;
116 return 1;
117}
118
119__setup("nfsrootdebug", nfs_root_debug);
120#endif
121
122/*
123 * Parse NFS server and directory information passed on the kernel
124 * command line.
125 *
126 * nfsroot=[<server-ip>:]<root-dir>[,<nfs-options>]
127 *
128 * If there is a "%s" token in the <root-dir> string, it is replaced
129 * by the ASCII-representation of the client's IP address.
130 */
131static int __init nfs_root_setup(char *line)
132{
133 ROOT_DEV = Root_NFS;
134
135 if (line[0] == '/' || line[0] == ',' || (line[0] >= '0' && line[0] <= '9')) {
136 strlcpy(nfs_root_parms, line, sizeof(nfs_root_parms));
137 } else {
138 size_t n = strlen(line) + sizeof(NFS_ROOT) - 1;
139 if (n >= sizeof(nfs_root_parms))
140 line[sizeof(nfs_root_parms) - sizeof(NFS_ROOT) - 2] = '\0';
141 sprintf(nfs_root_parms, NFS_ROOT, line);
142 }
143
144 /*
145 * Extract the IP address of the NFS server containing our
146 * root file system, if one was specified.
147 *
148 * Note: root_nfs_parse_addr() removes the server-ip from
149 * nfs_root_parms, if it exists.
150 */
151 root_server_addr = root_nfs_parse_addr(nfs_root_parms);
152
153 return 1;
154}
155
156__setup("nfsroot=", nfs_root_setup);
157
158static int __init root_nfs_copy(char *dest, const char *src,
159 const size_t destlen)
160{
161 if (strlcpy(dest, src, destlen) > destlen)
162 return -1;
163 return 0;
164}
165
166static int __init root_nfs_cat(char *dest, const char *src,
167 const size_t destlen)
168{
169 size_t len = strlen(dest);
170
171 if (len && dest[len - 1] != ',')
172 if (strlcat(dest, ",", destlen) > destlen)
173 return -1;
174
175 if (strlcat(dest, src, destlen) > destlen)
176 return -1;
177 return 0;
178}
179
180/*
181 * Parse out root export path and mount options from
182 * passed-in string @incoming.
183 *
184 * Copy the export path into @exppath.
185 */
186static int __init root_nfs_parse_options(char *incoming, char *exppath,
187 const size_t exppathlen)
188{
189 char *p;
190
191 /*
192 * Set the NFS remote path
193 */
194 p = strsep(&incoming, ",");
195 if (*p != '\0' && strcmp(p, "default") != 0)
196 if (root_nfs_copy(exppath, p, exppathlen))
197 return -1;
198
199 /*
200 * @incoming now points to the rest of the string; if it
201 * contains something, append it to our root options buffer
202 */
203 if (incoming != NULL && *incoming != '\0')
204 if (root_nfs_cat(nfs_root_options, incoming,
205 sizeof(nfs_root_options)))
206 return -1;
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 mand_options[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(mand_options, sizeof(mand_options), "nolock,addr=%pI4",
248 &servaddr);
249 if (root_nfs_cat(nfs_root_options, mand_options,
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{
298 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}