1 // SPDX-License-Identifier: GPL-2.0 1
2 /*
3 * Copyright (C) 1995, 1996 Gero Kuhlmann <g
4 *
5 * Allow an NFS filesystem to be mounted as r
6 * (1) Use the IP autoconfig mechanism to
7 * (2) Construct the device string and the
8 * option 17 and/or kernel command lin
9 * (3) When mount_root() sets up the root
10 * to the NFS client's regular mount i
11 *
12 *
13 * Changes:
14 *
15 * Alan Cox : Removed get_ad
16 * Alan Cox : Reformatted a
17 * Gero Kuhlmann : Code cleanup
18 * Michael Rausch : Fixed recognit
19 * Martin Mares : (2.0) Auto-configura
20 * Martin Mares : Manual selecti
21 * Martin Mares : Using network
22 * allowing the d
23 * for normal ope
24 * Martin Mares : Randomized tim
25 * installed to m
26 * Martin Mares : Code cleanup.
27 * Martin Mares : (2.1) BOOTP and RARP
28 * Martin Mares : Server hostnam
29 * Gerd Knorr : Fixed wired in
30 * Martin Mares : (2.2) "0.0.0.0" addr
31 * Martin Mares : RARP replies n
32 * Gero Kuhlmann : (2.3) Some bug fixes
33 * send me your n
34 * Linus so that
35 * _afterwards_ -
36 * Gero Kuhlmann : Last changes o
37 * Gero Kuhlmann : RARP replies a
38 * again. However
39 * different RARP
40 * Gero Kuhlmann : "0.0.0.0" addr
41 * now mapped to
42 * Gero Kuhlmann : Fixed a bug wh
43 * from being use
44 * Andy Walker : Allow to speci
45 * without giving
46 * Swen Thümmler : Allow to speci
47 * without giving
48 * for domainname
49 * DNS domain!).
50 * Jacek Zapala : Fixed a bug wh
51 * from nfsroot p
52 * Olaf Kirch : Adapted to new
53 * Jakub Jelinek : Free used code
54 * Marko Kohtala : Fixed some bug
55 * Martin Mares : Debug message
56 * Martin Mares : Changed to use
57 * code. BOOTP an
58 * Martin Mares : Default path n
59 * host IP addres
60 * address anyway
61 * Martin Mares : Use root_serve
62 * Martin Mares : Rewrote parame
63 * correct overri
64 * Trond Myklebust : Add in prelimi
65 * Fix bug in roo
66 * is NOT for the
67 * Hua Qin : Support for mo
68 * NFS over TCP.
69 * Fabian Frederick: Option parser
70 * Chuck Lever : Use super.c's
71 * Chuck Lever : Add "nfsrootde
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 rep
88 #define NFS_ROOT "/tftpboot/%s"
89
90 /* Default NFSROOT mount options. */
91 #if defined(CONFIG_NFS_V2)
92 #define NFS_DEF_OPTIONS "vers=2,tcp,rs
93 #elif defined(CONFIG_NFS_V3)
94 #define NFS_DEF_OPTIONS "vers=3,tcp,rs
95 #else
96 #define NFS_DEF_OPTIONS "vers=4,tcp,rs
97 #endif
98
99 /* Parameters passed from the kernel command l
100 static char nfs_root_parms[NFS_MAXPATHLEN + 1]
101
102 /* Text-based mount options passed to super.c
103 static char nfs_root_options[256] __initdata =
104
105 /* Address of NFS server */
106 static __be32 servaddr __initdata = htonl(INAD
107
108 /* Name of directory to mount */
109 static char nfs_export_path[NFS_MAXPATHLEN + 1
110
111 /* server:export path string passed to super.c
112 static char nfs_root_device[NFS_MAXPATHLEN + 1
113
114 #ifdef NFS_DEBUG
115 /*
116 * When the "nfsrootdebug" kernel command line
117 * enable debugging messages for NFSROOT.
118 */
119 static int __init nfs_root_debug(char *__unuse
120 {
121 nfs_debug |= NFSDBG_ROOT | NFSDBG_MOUN
122 return 1;
123 }
124
125 __setup("nfsrootdebug", nfs_root_debug);
126 #endif
127
128 /*
129 * Parse NFS server and directory information
130 * command line.
131 *
132 * nfsroot=[<server-ip>:]<root-dir>[,<nfs-opt
133 *
134 * If there is a "%s" token in the <root-dir>
135 * by the ASCII-representation of the client'
136 */
137 static int __init nfs_root_setup(char *line)
138 {
139 ROOT_DEV = Root_NFS;
140
141 if (line[0] == '/' || line[0] == ',' |
142 strscpy(nfs_root_parms, line,
143 } else {
144 size_t n = strlen(line) + size
145 if (n >= sizeof(nfs_root_parms
146 line[sizeof(nfs_root_p
147 sprintf(nfs_root_parms, NFS_RO
148 }
149
150 /*
151 * Extract the IP address of the NFS s
152 * root file system, if one was specif
153 *
154 * Note: root_nfs_parse_addr() removes
155 * nfs_root_parms, if it exists.
156 */
157 root_server_addr = root_nfs_parse_addr
158
159 return 1;
160 }
161
162 __setup("nfsroot=", nfs_root_setup);
163
164 static int __init root_nfs_copy(char *dest, co
165 const siz
166 {
167 if (strscpy(dest, src, destlen) == -E2
168 return -1;
169 return 0;
170 }
171
172 static int __init root_nfs_cat(char *dest, con
173 const size_t de
174 {
175 size_t len = strlen(dest);
176
177 if (len && dest[len - 1] != ',')
178 if (strlcat(dest, ",", destlen
179 return -1;
180
181 if (strlcat(dest, src, destlen) >= des
182 return -1;
183 return 0;
184 }
185
186 /*
187 * Parse out root export path and mount option
188 * passed-in string @incoming.
189 *
190 * Copy the export path into @exppath.
191 */
192 static int __init root_nfs_parse_options(char
193 const
194 {
195 char *p;
196
197 /*
198 * Set the NFS remote path
199 */
200 p = strsep(&incoming, ",");
201 if (*p != '\0' && strcmp(p, "default")
202 if (root_nfs_copy(exppath, p,
203 return -1;
204
205 /*
206 * @incoming now points to the rest of
207 * contains something, append it to ou
208 */
209 if (incoming != NULL && *incoming != '
210 if (root_nfs_cat(nfs_root_opti
211
212 return -1;
213 return 0;
214 }
215
216 /*
217 * Decode the export directory path name and
218 * the kernel command line. This has to be d
219 * use a dynamically acquired client IP addre
220 * root directory path.
221 *
222 * Returns zero if successful; otherwise -1 i
223 */
224 static int __init root_nfs_data(char *cmdline)
225 {
226 char mand_options[sizeof("nolock,addr=
227 int len, retval = -1;
228 char *tmp = NULL;
229 const size_t tmplen = sizeof(nfs_expor
230
231 tmp = kzalloc(tmplen, GFP_KERNEL);
232 if (tmp == NULL)
233 goto out_nomem;
234 strcpy(tmp, NFS_ROOT);
235
236 if (root_server_path[0] != '\0') {
237 dprintk("Root-NFS: DHCPv4 opti
238 root_server_path);
239 if (root_nfs_parse_options(roo
240 goto out_optionstoolon
241 }
242
243 if (cmdline[0] != '\0') {
244 dprintk("Root-NFS: nfsroot=%s\
245 if (root_nfs_parse_options(cmd
246 goto out_optionstoolon
247 }
248
249 /*
250 * Append mandatory options for nfsroo
251 * what has come before
252 */
253 snprintf(mand_options, sizeof(mand_opt
254 &servaddr);
255 if (root_nfs_cat(nfs_root_options, man
256
257 goto out_optionstoolong;
258
259 /*
260 * Set up nfs_root_device. For NFS mo
261 *
262 * server:/path
263 *
264 * At this point, utsname()->nodename
265 * IP address or hostname, set by ipco
266 * in tmp, substitute the nodename, th
267 * mess into nfs_root_device.
268 */
269 len = snprintf(nfs_export_path, sizeof
270 tmp, utsname()
271 if (len >= (int)sizeof(nfs_export_path
272 goto out_devnametoolong;
273 len = snprintf(nfs_root_device, sizeof
274 "%pI4:%s", &se
275 if (len >= (int)sizeof(nfs_root_device
276 goto out_devnametoolong;
277
278 retval = 0;
279
280 out:
281 kfree(tmp);
282 return retval;
283 out_nomem:
284 printk(KERN_ERR "Root-NFS: could not a
285 goto out;
286 out_optionstoolong:
287 printk(KERN_ERR "Root-NFS: mount optio
288 goto out;
289 out_devnametoolong:
290 printk(KERN_ERR "Root-NFS: root device
291 goto out;
292 }
293
294 /**
295 * nfs_root_data - Return prepared 'data' for
296 * @root_device: OUT: address of string contai
297 * @root_data: OUT: address of string containi
298 *
299 * Returns zero and sets @root_device and @roo
300 * otherwise -1 is returned.
301 */
302 int __init nfs_root_data(char **root_device, c
303 {
304 servaddr = root_server_addr;
305 if (servaddr == htonl(INADDR_NONE)) {
306 printk(KERN_ERR "Root-NFS: no
307 return -1;
308 }
309
310 if (root_nfs_data(nfs_root_parms) < 0)
311 return -1;
312
313 *root_device = nfs_root_device;
314 *root_data = nfs_root_options;
315 return 0;
316 }
317
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