[net-next-2.6.git] / fs / nfs / nfsroot.c

/*
 *  Copyright (C) 1995, 1996  Gero Kuhlmann <gero@gkminix.han.de>
 *
 *  Allow an NFS filesystem to be mounted as root. The way this works is:
 *     (1) Use the IP autoconfig mechanism to set local IP addresses and routes.
 *     (2) Construct the device string and the options string using DHCP
 *         option 17 and/or kernel command line options.
 *     (3) When mount_root() sets up the root file system, pass these strings
 *         to the NFS client's regular mount interface via sys_mount().
 *
 *
 *	Changes:
 *
 *	Alan Cox	:	Removed get_address name clash with FPU.
 *	Alan Cox	:	Reformatted a bit.
 *	Gero Kuhlmann	:	Code cleanup
 *	Michael Rausch  :	Fixed recognition of an incoming RARP answer.
 *	Martin Mares	: (2.0)	Auto-configuration via BOOTP supported.
 *	Martin Mares	:	Manual selection of interface & BOOTP/RARP.
 *	Martin Mares	:	Using network routes instead of host routes,
 *				allowing the default configuration to be used
 *				for normal operation of the host.
 *	Martin Mares	:	Randomized timer with exponential backoff
 *				installed to minimize network congestion.
 *	Martin Mares	:	Code cleanup.
 *	Martin Mares	: (2.1)	BOOTP and RARP made configuration options.
 *	Martin Mares	:	Server hostname generation fixed.
 *	Gerd Knorr	:	Fixed wired inode handling
 *	Martin Mares	: (2.2)	"0.0.0.0" addresses from command line ignored.
 *	Martin Mares	:	RARP replies not tested for server address.
 *	Gero Kuhlmann	: (2.3) Some bug fixes and code cleanup again (please
 *				send me your new patches _before_ bothering
 *				Linus so that I don' always have to cleanup
 *				_afterwards_ - thanks)
 *	Gero Kuhlmann	:	Last changes of Martin Mares undone.
 *	Gero Kuhlmann	: 	RARP replies are tested for specified server
 *				again. However, it's now possible to have
 *				different RARP and NFS servers.
 *	Gero Kuhlmann	:	"0.0.0.0" addresses from command line are
 *				now mapped to INADDR_NONE.
 *	Gero Kuhlmann	:	Fixed a bug which prevented BOOTP path name
 *				from being used (thanks to Leo Spiekman)
 *	Andy Walker	:	Allow to specify the NFS server in nfs_root
 *				without giving a path name
 *	Swen Thümmler	:	Allow to specify the NFS options in nfs_root
 *				without giving a path name. Fix BOOTP request
 *				for domainname (domainname is NIS domain, not
 *				DNS domain!). Skip dummy devices for BOOTP.
 *	Jacek Zapala	:	Fixed a bug which prevented server-ip address
 *				from nfsroot parameter from being used.
 *	Olaf Kirch	:	Adapted to new NFS code.
 *	Jakub Jelinek	:	Free used code segment.
 *	Marko Kohtala	:	Fixed some bugs.
 *	Martin Mares	:	Debug message cleanup
 *	Martin Mares	:	Changed to use the new generic IP layer autoconfig
 *				code. BOOTP and RARP moved there.
 *	Martin Mares	:	Default path now contains host name instead of
 *				host IP address (but host name defaults to IP
 *				address anyway).
 *	Martin Mares	:	Use root_server_addr appropriately during setup.
 *	Martin Mares	:	Rewrote parameter parsing, now hopefully giving
 *				correct overriding.
 *	Trond Myklebust :	Add in preliminary support for NFSv3 and TCP.
 *				Fix bug in root_nfs_addr(). nfs_data.namlen
 *				is NOT for the length of the hostname.
 *	Hua Qin		:	Support for mounting root file system via
 *				NFS over TCP.
 *	Fabian Frederick:	Option parser rebuilt (using parser lib)
 *	Chuck Lever	:	Use super.c's text-based mount option parsing
 *	Chuck Lever	:	Add "nfsrootdebug".
 */

#include <linux/types.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/nfs.h>
#include <linux/nfs_fs.h>
#include <linux/utsname.h>
#include <linux/root_dev.h>
#include <net/ipconfig.h>

#include "internal.h"

#define NFSDBG_FACILITY NFSDBG_ROOT

/* Default path we try to mount. "%s" gets replaced by our IP address */
#define NFS_ROOT		"/tftpboot/%s"

/* Parameters passed from the kernel command line */
static char nfs_root_parms[256] __initdata = "";

/* Text-based mount options passed to super.c */
static char nfs_root_options[256] __initdata = "";

/* Address of NFS server */
static __be32 servaddr __initdata = htonl(INADDR_NONE);

/* Name of directory to mount */
static char nfs_export_path[NFS_MAXPATHLEN + 1] __initdata = "";

/* server:export path string passed to super.c */
static char nfs_root_device[NFS_MAXPATHLEN + 1] __initdata = "";

#ifdef RPC_DEBUG
/*
 * When the "nfsrootdebug" kernel command line option is specified,
 * enable debugging messages for NFSROOT.
 */
static int __init nfs_root_debug(char *__unused)
{
	nfs_debug |= NFSDBG_ROOT | NFSDBG_MOUNT;
	return 1;
}

__setup("nfsrootdebug", nfs_root_debug);
#endif

/*
 *  Parse NFS server and directory information passed on the kernel
 *  command line.
 *
 *  nfsroot=[<server-ip>:]<root-dir>[,<nfs-options>]
 *
 *  If there is a "%s" token in the <root-dir> string, it is replaced
 *  by the ASCII-representation of the client's IP address.
 */
static int __init nfs_root_setup(char *line)
{
	ROOT_DEV = Root_NFS;

	if (line[0] == '/' || line[0] == ',' || (line[0] >= '0' && line[0] <= '9')) {
		strlcpy(nfs_root_parms, line, sizeof(nfs_root_parms));
	} else {
		size_t n = strlen(line) + sizeof(NFS_ROOT) - 1;
		if (n >= sizeof(nfs_root_parms))
			line[sizeof(nfs_root_parms) - sizeof(NFS_ROOT) - 2] = '\0';
		sprintf(nfs_root_parms, NFS_ROOT, line);
	}

	/*
	 * Extract the IP address of the NFS server containing our
	 * root file system, if one was specified.
	 *
	 * Note: root_nfs_parse_addr() removes the server-ip from
	 *	 nfs_root_parms, if it exists.
	 */
	root_server_addr = root_nfs_parse_addr(nfs_root_parms);

	return 1;
}

__setup("nfsroot=", nfs_root_setup);

static int __init root_nfs_copy(char *dest, const char *src,
				     const size_t destlen)
{
	if (strlcpy(dest, src, destlen) > destlen)
		return -1;
	return 0;
}

static int __init root_nfs_cat(char *dest, const char *src,
				  const size_t destlen)
{
	if (strlcat(dest, src, destlen) > destlen)
		return -1;
	return 0;
}

/*
 * Parse out root export path and mount options from
 * passed-in string @incoming.
 *
 * Copy the export path into @exppath.
 */
static int __init root_nfs_parse_options(char *incoming, char *exppath,
					 const size_t exppathlen)
{
	char *p;

	/*
	 * Set the NFS remote path
	 */
	p = strsep(&incoming, ",");
	if (*p != '\0' && strcmp(p, "default") != 0)
		if (root_nfs_copy(exppath, p, exppathlen))
			return -1;

	/*
	 * @incoming now points to the rest of the string; if it
	 * contains something, append it to our root options buffer
	 */
	if (incoming != NULL && *incoming != '\0')
		if (root_nfs_cat(nfs_root_options, incoming,
						sizeof(nfs_root_options)))
			return -1;

	/*
	 * Possibly prepare for more options to be appended
	 */
	if (nfs_root_options[0] != '\0' &&
	    nfs_root_options[strlen(nfs_root_options)] != ',')
		if (root_nfs_cat(nfs_root_options, ",",
						sizeof(nfs_root_options)))
			return -1;

	return 0;
}

/*
 *  Decode the export directory path name and NFS options from
 *  the kernel command line.  This has to be done late in order to
 *  use a dynamically acquired client IP address for the remote
 *  root directory path.
 *
 *  Returns zero if successful; otherwise -1 is returned.
 */
static int __init root_nfs_data(char *cmdline)
{
	char addr_option[sizeof("nolock,addr=") + INET_ADDRSTRLEN + 1];
	int len, retval = -1;
	char *tmp = NULL;
	const size_t tmplen = sizeof(nfs_export_path);

	tmp = kzalloc(tmplen, GFP_KERNEL);
	if (tmp == NULL)
		goto out_nomem;
	strcpy(tmp, NFS_ROOT);

	if (root_server_path[0] != '\0') {
		dprintk("Root-NFS: DHCPv4 option 17: %s\n",
			root_server_path);
		if (root_nfs_parse_options(root_server_path, tmp, tmplen))
			goto out_optionstoolong;
	}

	if (cmdline[0] != '\0') {
		dprintk("Root-NFS: nfsroot=%s\n", cmdline);
		if (root_nfs_parse_options(cmdline, tmp, tmplen))
			goto out_optionstoolong;
	}

	/*
	 * Append mandatory options for nfsroot so they override
	 * what has come before
	 */
	snprintf(addr_option, sizeof(addr_option), "nolock,addr=%pI4",
			&servaddr);
	if (root_nfs_cat(nfs_root_options, addr_option,
						sizeof(nfs_root_options)))
		goto out_optionstoolong;

	/*
	 * Set up nfs_root_device.  For NFS mounts, this looks like
	 *
	 *	server:/path
	 *
	 * At this point, utsname()->nodename contains our local
	 * IP address or hostname, set by ipconfig.  If "%s" exists
	 * in tmp, substitute the nodename, then shovel the whole
	 * mess into nfs_root_device.
	 */
	len = snprintf(nfs_export_path, sizeof(nfs_export_path),
				tmp, utsname()->nodename);
	if (len > (int)sizeof(nfs_export_path))
		goto out_devnametoolong;
	len = snprintf(nfs_root_device, sizeof(nfs_root_device),
				"%pI4:%s", &servaddr, nfs_export_path);
	if (len > (int)sizeof(nfs_root_device))
		goto out_devnametoolong;

	retval = 0;

out:
	kfree(tmp);
	return retval;
out_nomem:
	printk(KERN_ERR "Root-NFS: could not allocate memory\n");
	goto out;
out_optionstoolong:
	printk(KERN_ERR "Root-NFS: mount options string too long\n");
	goto out;
out_devnametoolong:
	printk(KERN_ERR "Root-NFS: root device name too long.\n");
	goto out;
}

/**
 * nfs_root_data - Return prepared 'data' for NFSROOT mount
 * @root_device: OUT: address of string containing NFSROOT device
 * @root_data: OUT: address of string containing NFSROOT mount options
 *
 * Returns zero and sets @root_device and @root_data if successful,
 * otherwise -1 is returned.
 */
int __init nfs_root_data(char **root_device, char **root_data)
{
	servaddr = root_server_addr;
	if (servaddr == htonl(INADDR_NONE)) {
		printk(KERN_ERR "Root-NFS: no NFS server address\n");
		return -1;
	}

	if (root_nfs_data(nfs_root_parms) < 0)
		return -1;

	*root_device = nfs_root_device;
	*root_data = nfs_root_options;
	return 0;
}
Commit	Line	Data
1da177e4	1	/*
1da177e4 LT	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.
56463e50 CL	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().
1da177e4 LT	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
96de0e25	45	* Swen Thümmler : Allow to specify the NFS options in nfs_root
1da177e4 LT	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)
56463e50	69	* Chuck Lever : Use super.c's text-based mount option parsing
306a0753	70	* Chuck Lever : Add "nfsrootdebug".
56463e50	71	*/
1da177e4	72
1da177e4 LT	73	#include <linux/types.h>
1da177e4 LT	74	#include <linux/string.h>
1da177e4	75	#include <linux/init.h>
1da177e4 LT	76	#include <linux/nfs.h>
1da177e4 LT	77	#include <linux/nfs_fs.h>
1da177e4	78	#include <linux/utsname.h>
1da177e4 LT	79	#include <linux/root_dev.h>
1da177e4 LT	80	#include <net/ipconfig.h>
1da177e4	81
146ec944 CL	82	#include "internal.h"
146ec944 CL	83
1da177e4 LT	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	/* Parameters passed from the kernel command line */
60ac0368	90	static char nfs_root_parms[256] __initdata = "";
1da177e4	91
56463e50 CL	92	/* Text-based mount options passed to super.c */
	93	static char nfs_root_options[256] __initdata = "";
	94
1da177e4	95	/* Address of NFS server */
8d232103	96	static __be32 servaddr __initdata = htonl(INADDR_NONE);
1da177e4 LT	97
1da177e4 LT	98	/* Name of directory to mount */
56463e50 CL	99	static char nfs_export_path[NFS_MAXPATHLEN + 1] __initdata = "";
	100
	101	/* server:export path string passed to super.c */
	102	static char nfs_root_device[NFS_MAXPATHLEN + 1] __initdata = "";
1da177e4	103
036a1075	104	#ifdef RPC_DEBUG
306a0753 CL	105	/*
	106	* When the "nfsrootdebug" kernel command line option is specified,
	107	* enable debugging messages for NFSROOT.
	108	*/
	109	static 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);
036a1075	116	#endif
306a0753	117
1da177e4 LT	118	/*
	119	* Parse NFS server and directory information passed on the kernel
	120	* command line.
60ac0368 CL	121	*
	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.
1da177e4 LT	126	*/
	127	static int __init nfs_root_setup(char *line)
	128	{
	129	ROOT_DEV = Root_NFS;
60ac0368	130
1da177e4	131	if (line[0] == '/' \|\| line[0] == ',' \|\| (line[0] >= '0' && line[0] <= '9')) {
60ac0368	132	strlcpy(nfs_root_parms, line, sizeof(nfs_root_parms));
1da177e4	133	} else {
60ac0368 CL	134	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);
1da177e4	138	}
60ac0368 CL	139
	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
1da177e4 LT	149	return 1;
	150	}
	151
	152	__setup("nfsroot=", nfs_root_setup);
	153
56463e50 CL	154	static 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
	162	static 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	*/
	176	static 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	*/
218	static 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
274	out:
275	kfree(tmp);
276	return retval;
277	out_nomem:
278	printk(KERN_ERR "Root-NFS: could not allocate memory\n");
279	goto out;
280	out_optionstoolong:
281	printk(KERN_ERR "Root-NFS: mount options string too long\n");
282	goto out;
283	out_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	*/
296	int __init nfs_root_data(char root_device, char root_data)
297	{
56463e50 CL	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	}