/*
 * In-kernel MOUNT protocol client
 *
 * Copyright (C) 1997, Olaf Kirch <okir@monad.swb.de>
 */

#include <linux/types.h>
#include <linux/socket.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/uio.h>
#include <linux/net.h>
#include <linux/in.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/sched.h>
#include <linux/nfs_fs.h>

#ifdef RPC_DEBUG
# define NFSDBG_FACILITY        NFSDBG_MOUNT
#endif

static struct rpc_program       mnt_program;

struct mnt_fhstatus {
        u32 status;
        struct nfs_fh *fh;
};

/**
 * nfs_mount - Obtain an NFS file handle for the given host and path
 * @addr: pointer to server's address
 * @len: size of server's address
 * @hostname: name of server host, or NULL
 * @path: pointer to string containing export path to mount
 * @version: mount version to use for this request
 * @protocol: transport protocol to use for thie request
 * @fh: pointer to location to place returned file handle
 *
 * Uses default timeout parameters specified by underlying transport.
 */
int nfs_mount(struct sockaddr *addr, size_t len, char *hostname, char *path,
              int version, int protocol, struct nfs_fh *fh)
{
        struct mnt_fhstatus     result = {
                .fh             = fh
        };
        struct rpc_message msg  = {
                .rpc_argp       = path,
                .rpc_resp       = &result,
        };
        struct rpc_create_args args = {
                .protocol       = protocol,
                .address        = addr,
                .addrsize       = len,
                .servername     = hostname,
                .program        = &mnt_program,
                .version        = version,
                .authflavor     = RPC_AUTH_UNIX,
                .flags          = 0,
        };
        struct rpc_clnt         *mnt_clnt;
        int                     status;

        dprintk("NFS: sending MNT request for %s:%s\n",
                (hostname ? hostname : "server"), path);

        mnt_clnt = rpc_create(&args);
        if (IS_ERR(mnt_clnt))
                goto out_clnt_err;

        if (version == NFS_MNT3_VERSION)
                msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC3_MNT];
        else
                msg.rpc_proc = &mnt_clnt->cl_procinfo[MNTPROC_MNT];

        status = rpc_call_sync(mnt_clnt, &msg, 0);
        rpc_shutdown_client(mnt_clnt);

        if (status < 0)
                goto out_call_err;
        if (result.status != 0)
                goto out_mnt_err;

        dprintk("NFS: MNT request succeeded\n");
        status = 0;

out:
        return status;

out_clnt_err:
        status = PTR_ERR(mnt_clnt);
        dprintk("NFS: failed to create RPC client, status=%d\n", status);
        goto out;

out_call_err:
        dprintk("NFS: failed to start MNT request, status=%d\n", status);
        goto out;

out_mnt_err:
        dprintk("NFS: MNT server returned result %d\n", result.status);
        status = -EACCES;
        goto out;
}

/*
 * XDR encode/decode functions for MOUNT
 */
static int xdr_encode_dirpath(struct rpc_rqst *req, __be32 *p,
                              const char *path)
{
        p = xdr_encode_string(p, path);

        req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
        return 0;
}

static int xdr_decode_fhstatus(struct rpc_rqst *req, __be32 *p,
                               struct mnt_fhstatus *res)
{
        struct nfs_fh *fh = res->fh;

        if ((res->status = ntohl(*p++)) == 0) {
                fh->size = NFS2_FHSIZE;
                memcpy(fh->data, p, NFS2_FHSIZE);
        }
        return 0;
}

static int xdr_decode_fhstatus3(struct rpc_rqst *req, __be32 *p,
                                struct mnt_fhstatus *res)
{
        struct nfs_fh *fh = res->fh;

        if ((res->status = ntohl(*p++)) == 0) {
                int size = ntohl(*p++);
                if (size <= NFS3_FHSIZE) {
                        fh->size = size;
                        memcpy(fh->data, p, size);
                } else
                        res->status = -EBADHANDLE;
        }
        return 0;
}

#define MNT_dirpath_sz          (1 + 256)
#define MNT_fhstatus_sz         (1 + 8)
#define MNT_fhstatus3_sz        (1 + 16)

static struct rpc_procinfo mnt_procedures[] = {
        [MNTPROC_MNT] = {
                .p_proc         = MNTPROC_MNT,
                .p_encode       = (kxdrproc_t) xdr_encode_dirpath,
                .p_decode       = (kxdrproc_t) xdr_decode_fhstatus,
                .p_arglen       = MNT_dirpath_sz,
                .p_replen       = MNT_fhstatus_sz,
                .p_statidx      = MNTPROC_MNT,
                .p_name         = "MOUNT",
        },
};

static struct rpc_procinfo mnt3_procedures[] = {
        [MOUNTPROC3_MNT] = {
                .p_proc         = MOUNTPROC3_MNT,
                .p_encode       = (kxdrproc_t) xdr_encode_dirpath,
                .p_decode       = (kxdrproc_t) xdr_decode_fhstatus3,
                .p_arglen       = MNT_dirpath_sz,
                .p_replen       = MNT_fhstatus3_sz,
                .p_statidx      = MOUNTPROC3_MNT,
                .p_name         = "MOUNT",
        },
};


static struct rpc_version mnt_version1 = {
        .number         = 1,
        .nrprocs        = 2,
        .procs          = mnt_procedures,
};

static struct rpc_version mnt_version3 = {
        .number         = 3,
        .nrprocs        = 2,
        .procs          = mnt3_procedures,
};

static struct rpc_version *mnt_version[] = {
        NULL,
        &mnt_version1,
        NULL,
        &mnt_version3,
};

static struct rpc_stat mnt_stats;

static struct rpc_program mnt_program = {
        .name           = "mount",
        .number         = NFS_MNT_PROGRAM,
        .nrvers         = ARRAY_SIZE(mnt_version),
        .version        = mnt_version,
        .stats          = &mnt_stats,
};