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root/fs/nfs/nfsroot.c

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DEFINITIONS

This source file includes following definitions.
  1. root_nfs_parse
  2. root_nfs_name
  3. root_nfs_addr
  4. root_nfs_print
  5. root_nfs_init
  6. nfs_root_setup
  7. set_sockaddr
  8. root_nfs_getport
  9. root_nfs_ports
  10. root_nfs_get_handle
  11. nfs_root_data

/*
 *  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) Handle RPC negotiation with the system which replied to RARP or
 *         was reported as a boot server by BOOTP or manually.
 *     (3) The actual mounting is done later, when init() is running.
 *
 *
 *      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)
*/

#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/xprtsock.h>
#include <linux/nfs.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/in.h>
#include <linux/major.h>
#include <linux/utsname.h>
#include <linux/inet.h>
#include <linux/root_dev.h>
#include <net/ipconfig.h>
#include <linux/parser.h>

/* Define this to allow debugging output */
#undef NFSROOT_DEBUG
#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_name[256] __initdata = "";

/* Address of NFS server */
static __be32 servaddr __initdata = 0;

/* Name of directory to mount */
static char nfs_path[NFS_MAXPATHLEN] __initdata = { 0, };

/* NFS-related data */
static struct nfs_mount_data nfs_data __initdata = { 0, };/* NFS mount info */
static int nfs_port __initdata = 0;             /* Port to connect to for NFS */
static int mount_port __initdata = 0;           /* Mount daemon port number */


/***************************************************************************

                             Parsing of options

 ***************************************************************************/

enum {
        /* Options that take integer arguments */
        Opt_port, Opt_rsize, Opt_wsize, Opt_timeo, Opt_retrans, Opt_acregmin,
        Opt_acregmax, Opt_acdirmin, Opt_acdirmax,
        /* Options that take no arguments */
        Opt_soft, Opt_hard, Opt_intr,
        Opt_nointr, Opt_posix, Opt_noposix, Opt_cto, Opt_nocto, Opt_ac, 
        Opt_noac, Opt_lock, Opt_nolock, Opt_v2, Opt_v3, Opt_udp, Opt_tcp,
        Opt_acl, Opt_noacl,
        /* Error token */
        Opt_err
};

static match_table_t __initconst tokens = {
        {Opt_port, "port=%u"},
        {Opt_rsize, "rsize=%u"},
        {Opt_wsize, "wsize=%u"},
        {Opt_timeo, "timeo=%u"},
        {Opt_retrans, "retrans=%u"},
        {Opt_acregmin, "acregmin=%u"},
        {Opt_acregmax, "acregmax=%u"},
        {Opt_acdirmin, "acdirmin=%u"},
        {Opt_acdirmax, "acdirmax=%u"},
        {Opt_soft, "soft"},
        {Opt_hard, "hard"},
        {Opt_intr, "intr"},
        {Opt_nointr, "nointr"},
        {Opt_posix, "posix"},
        {Opt_noposix, "noposix"},
        {Opt_cto, "cto"},
        {Opt_nocto, "nocto"},
        {Opt_ac, "ac"},
        {Opt_noac, "noac"},
        {Opt_lock, "lock"},
        {Opt_nolock, "nolock"},
        {Opt_v2, "nfsvers=2"},
        {Opt_v2, "v2"},
        {Opt_v3, "nfsvers=3"},
        {Opt_v3, "v3"},
        {Opt_udp, "proto=udp"},
        {Opt_udp, "udp"},
        {Opt_tcp, "proto=tcp"},
        {Opt_tcp, "tcp"},
        {Opt_acl, "acl"},
        {Opt_noacl, "noacl"},
        {Opt_err, NULL}
        
};

/*
 *  Parse option string.
 */

static int __init root_nfs_parse(char *name, char *buf)
{

        char *p;
        substring_t args[MAX_OPT_ARGS];
        int option;

        if (!name)
                return 1;

        /* Set the NFS remote path */
        p = strsep(&name, ",");
        if (p[0] != '\0' && strcmp(p, "default") != 0)
                strlcpy(buf, p, NFS_MAXPATHLEN);

        while ((p = strsep (&name, ",")) != NULL) {
                int token; 
                if (!*p)
                        continue;
                token = match_token(p, tokens, args);

                /* %u tokens only. Beware if you add new tokens! */
                if (token < Opt_soft && match_int(&args[0], &option))
                        return 0;
                switch (token) {
                        case Opt_port:
                                nfs_port = option;
                                break;
                        case Opt_rsize:
                                nfs_data.rsize = option;
                                break;
                        case Opt_wsize:
                                nfs_data.wsize = option;
                                break;
                        case Opt_timeo:
                                nfs_data.timeo = option;
                                break;
                        case Opt_retrans:
                                nfs_data.retrans = option;
                                break;
                        case Opt_acregmin:
                                nfs_data.acregmin = option;
                                break;
                        case Opt_acregmax:
                                nfs_data.acregmax = option;
                                break;
                        case Opt_acdirmin:
                                nfs_data.acdirmin = option;
                                break;
                        case Opt_acdirmax:
                                nfs_data.acdirmax = option;
                                break;
                        case Opt_soft:
                                nfs_data.flags |= NFS_MOUNT_SOFT;
                                break;
                        case Opt_hard:
                                nfs_data.flags &= ~NFS_MOUNT_SOFT;
                                break;
                        case Opt_intr:
                        case Opt_nointr:
                                break;
                        case Opt_posix:
                                nfs_data.flags |= NFS_MOUNT_POSIX;
                                break;
                        case Opt_noposix:
                                nfs_data.flags &= ~NFS_MOUNT_POSIX;
                                break;
                        case Opt_cto:
                                nfs_data.flags &= ~NFS_MOUNT_NOCTO;
                                break;
                        case Opt_nocto:
                                nfs_data.flags |= NFS_MOUNT_NOCTO;
                                break;
                        case Opt_ac:
                                nfs_data.flags &= ~NFS_MOUNT_NOAC;
                                break;
                        case Opt_noac:
                                nfs_data.flags |= NFS_MOUNT_NOAC;
                                break;
                        case Opt_lock:
                                nfs_data.flags &= ~NFS_MOUNT_NONLM;
                                break;
                        case Opt_nolock:
                                nfs_data.flags |= NFS_MOUNT_NONLM;
                                break;
                        case Opt_v2:
                                nfs_data.flags &= ~NFS_MOUNT_VER3;
                                break;
                        case Opt_v3:
                                nfs_data.flags |= NFS_MOUNT_VER3;
                                break;
                        case Opt_udp:
                                nfs_data.flags &= ~NFS_MOUNT_TCP;
                                break;
                        case Opt_tcp:
                                nfs_data.flags |= NFS_MOUNT_TCP;
                                break;
                        case Opt_acl:
                                nfs_data.flags &= ~NFS_MOUNT_NOACL;
                                break;
                        case Opt_noacl:
                                nfs_data.flags |= NFS_MOUNT_NOACL;
                                break;
                        default:
                                printk(KERN_WARNING "Root-NFS: unknown "
                                        "option: %s\n", p);
                                return 0;
                }
        }

        return 1;
}

/*
 *  Prepare the NFS data structure and parse all options.
 */
static int __init root_nfs_name(char *name)
{
        static char buf[NFS_MAXPATHLEN] __initdata;
        char *cp;

        /* Set some default values */
        memset(&nfs_data, 0, sizeof(nfs_data));
        nfs_port          = -1;
        nfs_data.version  = NFS_MOUNT_VERSION;
        nfs_data.flags    = NFS_MOUNT_NONLM;    /* No lockd in nfs root yet */
        nfs_data.rsize    = NFS_DEF_FILE_IO_SIZE;
        nfs_data.wsize    = NFS_DEF_FILE_IO_SIZE;
        nfs_data.acregmin = NFS_DEF_ACREGMIN;
        nfs_data.acregmax = NFS_DEF_ACREGMAX;
        nfs_data.acdirmin = NFS_DEF_ACDIRMIN;
        nfs_data.acdirmax = NFS_DEF_ACDIRMAX;
        strcpy(buf, NFS_ROOT);

        /* Process options received from the remote server */
        root_nfs_parse(root_server_path, buf);

        /* Override them by options set on kernel command-line */
        root_nfs_parse(name, buf);

        cp = utsname()->nodename;
        if (strlen(buf) + strlen(cp) > NFS_MAXPATHLEN) {
                printk(KERN_ERR "Root-NFS: Pathname for remote directory too long.\n");
                return -1;
        }
        sprintf(nfs_path, buf, cp);

        return 1;
}


/*
 *  Get NFS server address.
 */
static int __init root_nfs_addr(void)
{
        if ((servaddr = root_server_addr) == htonl(INADDR_NONE)) {
                printk(KERN_ERR "Root-NFS: No NFS server available, giving up.\n");
                return -1;
        }

        snprintf(nfs_data.hostname, sizeof(nfs_data.hostname),
                 "%u.%u.%u.%u", NIPQUAD(servaddr));
        return 0;
}

/*
 *  Tell the user what's going on.
 */
#ifdef NFSROOT_DEBUG
static void __init root_nfs_print(void)
{
        printk(KERN_NOTICE "Root-NFS: Mounting %s on server %s as root\n",
                nfs_path, nfs_data.hostname);
        printk(KERN_NOTICE "Root-NFS:     rsize = %d, wsize = %d, timeo = %d, retrans = %d\n",
                nfs_data.rsize, nfs_data.wsize, nfs_data.timeo, nfs_data.retrans);
        printk(KERN_NOTICE "Root-NFS:     acreg (min,max) = (%d,%d), acdir (min,max) = (%d,%d)\n",
                nfs_data.acregmin, nfs_data.acregmax,
                nfs_data.acdirmin, nfs_data.acdirmax);
        printk(KERN_NOTICE "Root-NFS:     nfsd port = %d, mountd port = %d, flags = %08x\n",
                nfs_port, mount_port, nfs_data.flags);
}
#endif


static int __init root_nfs_init(void)
{
#ifdef NFSROOT_DEBUG
        nfs_debug |= NFSDBG_ROOT;
#endif

        /*
         * Decode the root directory path name and NFS options from
         * the kernel command line. This has to go here in order to
         * be able to use the client IP address for the remote root
         * directory (necessary for pure RARP booting).
         */
        if (root_nfs_name(nfs_root_name) < 0 ||
            root_nfs_addr() < 0)
                return -1;

#ifdef NFSROOT_DEBUG
        root_nfs_print();
#endif

        return 0;
}


/*
 *  Parse NFS server and directory information passed on the kernel
 *  command line.
 */
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_name, line, sizeof(nfs_root_name));
        } else {
                int n = strlen(line) + sizeof(NFS_ROOT) - 1;
                if (n >= sizeof(nfs_root_name))
                        line[sizeof(nfs_root_name) - sizeof(NFS_ROOT) - 2] = '\0';
                sprintf(nfs_root_name, NFS_ROOT, line);
        }
        root_server_addr = root_nfs_parse_addr(nfs_root_name);
        return 1;
}

__setup("nfsroot=", nfs_root_setup);

/***************************************************************************

               Routines to actually mount the root directory

 ***************************************************************************/

/*
 *  Construct sockaddr_in from address and port number.
 */
static inline void
set_sockaddr(struct sockaddr_in *sin, __be32 addr, __be16 port)
{
        sin->sin_family = AF_INET;
        sin->sin_addr.s_addr = addr;
        sin->sin_port = port;
}

/*
 *  Query server portmapper for the port of a daemon program.
 */
static int __init root_nfs_getport(int program, int version, int proto)
{
        struct sockaddr_in sin;

        printk(KERN_NOTICE "Looking up port of RPC %d/%d on %u.%u.%u.%u\n",
                program, version, NIPQUAD(servaddr));
        set_sockaddr(&sin, servaddr, 0);
        return rpcb_getport_sync(&sin, program, version, proto);
}


/*
 *  Use portmapper to find mountd and nfsd port numbers if not overriden
 *  by the user. Use defaults if portmapper is not available.
 *  XXX: Is there any nfs server with no portmapper?
 */
static int __init root_nfs_ports(void)
{
        int port;
        int nfsd_ver, mountd_ver;
        int nfsd_port, mountd_port;
        int proto;

        if (nfs_data.flags & NFS_MOUNT_VER3) {
                nfsd_ver = NFS3_VERSION;
                mountd_ver = NFS_MNT3_VERSION;
                nfsd_port = NFS_PORT;
                mountd_port = NFS_MNT_PORT;
        } else {
                nfsd_ver = NFS2_VERSION;
                mountd_ver = NFS_MNT_VERSION;
                nfsd_port = NFS_PORT;
                mountd_port = NFS_MNT_PORT;
        }

        proto = (nfs_data.flags & NFS_MOUNT_TCP) ? IPPROTO_TCP : IPPROTO_UDP;

        if (nfs_port < 0) {
                if ((port = root_nfs_getport(NFS_PROGRAM, nfsd_ver, proto)) < 0) {
                        printk(KERN_ERR "Root-NFS: Unable to get nfsd port "
                                        "number from server, using default\n");
                        port = nfsd_port;
                }
                nfs_port = port;
                dprintk("Root-NFS: Portmapper on server returned %d "
                        "as nfsd port\n", port);
        }

        if ((port = root_nfs_getport(NFS_MNT_PROGRAM, mountd_ver, proto)) < 0) {
                printk(KERN_ERR "Root-NFS: Unable to get mountd port "
                                "number from server, using default\n");
                port = mountd_port;
        }
        mount_port = port;
        dprintk("Root-NFS: mountd port is %d\n", port);

        return 0;
}


/*
 *  Get a file handle from the server for the directory which is to be
 *  mounted.
 */
static int __init root_nfs_get_handle(void)
{
        struct nfs_fh fh;
        struct sockaddr_in sin;
        int status;
        int protocol = (nfs_data.flags & NFS_MOUNT_TCP) ?
                                        XPRT_TRANSPORT_TCP : XPRT_TRANSPORT_UDP;
        int version = (nfs_data.flags & NFS_MOUNT_VER3) ?
                                        NFS_MNT3_VERSION : NFS_MNT_VERSION;

        set_sockaddr(&sin, servaddr, htons(mount_port));
        status = nfs_mount((struct sockaddr *) &sin, sizeof(sin), NULL,
                           nfs_path, version, protocol, &fh);
        if (status < 0)
                printk(KERN_ERR "Root-NFS: Server returned error %d "
                                "while mounting %s\n", status, nfs_path);
        else {
                nfs_data.root.size = fh.size;
                memcpy(nfs_data.root.data, fh.data, fh.size);
        }

        return status;
}

/*
 *  Get the NFS port numbers and file handle, and return the prepared 'data'
 *  argument for mount() if everything went OK. Return NULL otherwise.
 */
void * __init nfs_root_data(void)
{
        if (root_nfs_init() < 0
         || root_nfs_ports() < 0
         || root_nfs_get_handle() < 0)
                return NULL;
        set_sockaddr((struct sockaddr_in *) &nfs_data.addr, servaddr, htons(nfs_port));
        return (void*)&nfs_data;
}

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