mount_clnt.c

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/*
 * In-kernel MOUNT protocol client
 *
 * Copyright (C) 1997, Olaf Kirch <[email protected]>
 */

#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>
#include "internal.h"

#ifdef NFS_DEBUG
# define NFSDBG_FACILITY    NFSDBG_MOUNT
#endif

/*
 * Defined by RFC 1094, section A.3; and RFC 1813, section 5.1.4
 */
#define MNTPATHLEN      (1024)

/*
 * XDR data type sizes
 */
#define encode_dirpath_sz   (1 + XDR_QUADLEN(MNTPATHLEN))
#define MNT_status_sz       (1)
#define MNT_fhs_status_sz   (1)
#define MNT_fhandle_sz      XDR_QUADLEN(NFS2_FHSIZE)
#define MNT_fhandle3_sz     (1 + XDR_QUADLEN(NFS3_FHSIZE))
#define MNT_authflav3_sz    (1 + NFS_MAX_SECFLAVORS)

/*
 * XDR argument and result sizes
 */
#define MNT_enc_dirpath_sz  encode_dirpath_sz
#define MNT_dec_mountres_sz (MNT_status_sz + MNT_fhandle_sz)
#define MNT_dec_mountres3_sz    (MNT_status_sz + MNT_fhandle_sz + \
                 MNT_authflav3_sz)

/*
 * Defined by RFC 1094, section A.5
 */
enum {
    MOUNTPROC_NULL      = 0,
    MOUNTPROC_MNT       = 1,
    MOUNTPROC_DUMP      = 2,
    MOUNTPROC_UMNT      = 3,
    MOUNTPROC_UMNTALL   = 4,
    MOUNTPROC_EXPORT    = 5,
};

/*
 * Defined by RFC 1813, section 5.2
 */
enum {
    MOUNTPROC3_NULL     = 0,
    MOUNTPROC3_MNT      = 1,
    MOUNTPROC3_DUMP     = 2,
    MOUNTPROC3_UMNT     = 3,
    MOUNTPROC3_UMNTALL  = 4,
    MOUNTPROC3_EXPORT   = 5,
};

static const struct rpc_program mnt_program;

/*
 * Defined by OpenGroup XNFS Version 3W, chapter 8
 */
enum mountstat {
    MNT_OK          = 0,
    MNT_EPERM       = 1,
    MNT_ENOENT      = 2,
    MNT_EACCES      = 13,
    MNT_EINVAL      = 22,
};

static struct {
    u32 status;
    int errno;
} mnt_errtbl[] = {
    { .status = MNT_OK,         .errno = 0,     },
    { .status = MNT_EPERM,          .errno = -EPERM,    },
    { .status = MNT_ENOENT,         .errno = -ENOENT,   },
    { .status = MNT_EACCES,         .errno = -EACCES,   },
    { .status = MNT_EINVAL,         .errno = -EINVAL,   },
};

/*
 * Defined by RFC 1813, section 5.1.5
 */
enum mountstat3 {
    MNT3_OK         = 0,        /* no error */
    MNT3ERR_PERM        = 1,        /* Not owner */
    MNT3ERR_NOENT       = 2,        /* No such file or directory */
    MNT3ERR_IO      = 5,        /* I/O error */
    MNT3ERR_ACCES       = 13,       /* Permission denied */
    MNT3ERR_NOTDIR      = 20,       /* Not a directory */
    MNT3ERR_INVAL       = 22,       /* Invalid argument */
    MNT3ERR_NAMETOOLONG = 63,       /* Filename too long */
    MNT3ERR_NOTSUPP     = 10004,    /* Operation not supported */
    MNT3ERR_SERVERFAULT = 10006,    /* A failure on the server */
};

static struct {
    u32 status;
    int errno;
} mnt3_errtbl[] = {
    { .status = MNT3_OK,            .errno = 0,     },
    { .status = MNT3ERR_PERM,       .errno = -EPERM,    },
    { .status = MNT3ERR_NOENT,      .errno = -ENOENT,   },
    { .status = MNT3ERR_IO,         .errno = -EIO,      },
    { .status = MNT3ERR_ACCES,      .errno = -EACCES,   },
    { .status = MNT3ERR_NOTDIR,     .errno = -ENOTDIR,  },
    { .status = MNT3ERR_INVAL,      .errno = -EINVAL,   },
    { .status = MNT3ERR_NAMETOOLONG,    .errno = -ENAMETOOLONG, },
    { .status = MNT3ERR_NOTSUPP,        .errno = -ENOTSUPP, },
    { .status = MNT3ERR_SERVERFAULT,    .errno = -EREMOTEIO,    },
};

struct mountres {
    int errno;
    struct nfs_fh *fh;
    unsigned int *auth_count;
    rpc_authflavor_t *auth_flavors;
};

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

int nfs_mount(struct nfs_mount_request *info)
{
    struct mountres result = {
        .fh     = info->fh,
        .auth_count = info->auth_flav_len,
        .auth_flavors   = info->auth_flavs,
    };
    struct rpc_message msg  = {
        .rpc_argp   = info->dirpath,
        .rpc_resp   = &result,
    };
    struct rpc_create_args args = {
        .net        = info->net,
        .protocol   = info->protocol,
        .address    = info->sap,
        .addrsize   = info->salen,
        .servername = info->hostname,
        .program    = &mnt_program,
        .version    = info->version,
        .authflavor = RPC_AUTH_UNIX,
    };
    struct rpc_clnt     *mnt_clnt;
    int         status;

    dprintk("NFS: sending MNT request for %s:%s\n",
        (info->hostname ? info->hostname : "server"),
            info->dirpath);

    if (info->noresvport)
        args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;

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

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

    status = rpc_call_sync(mnt_clnt, &msg, RPC_TASK_SOFT|RPC_TASK_TIMEOUT);
    rpc_shutdown_client(mnt_clnt);

    if (status < 0)
        goto out_call_err;
    if (result.errno != 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 MNT RPC client, status=%d\n", status);
    goto out;

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

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

void nfs_umount(const struct nfs_mount_request *info)
{
    static const struct rpc_timeout nfs_umnt_timeout = {
        .to_initval = 1 * HZ,
        .to_maxval = 3 * HZ,
        .to_retries = 2,
    };
    struct rpc_create_args args = {
        .net        = info->net,
        .protocol   = IPPROTO_UDP,
        .address    = info->sap,
        .addrsize   = info->salen,
        .timeout    = &nfs_umnt_timeout,
        .servername = info->hostname,
        .program    = &mnt_program,
        .version    = info->version,
        .authflavor = RPC_AUTH_UNIX,
        .flags      = RPC_CLNT_CREATE_NOPING,
    };
    struct rpc_message msg  = {
        .rpc_argp   = info->dirpath,
    };
    struct rpc_clnt *clnt;
    int status;

    if (info->noresvport)
        args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;

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

    dprintk("NFS: sending UMNT request for %s:%s\n",
        (info->hostname ? info->hostname : "server"), info->dirpath);

    if (info->version == NFS_MNT3_VERSION)
        msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC3_UMNT];
    else
        msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC_UMNT];

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

    if (unlikely(status < 0))
        goto out_call_err;

    return;

out_clnt_err:
    dprintk("NFS: failed to create UMNT RPC client, status=%ld\n",
            PTR_ERR(clnt));
    return;

out_call_err:
    dprintk("NFS: UMNT request failed, status=%d\n", status);
}

/*
 * XDR encode/decode functions for MOUNT
 */

static void encode_mntdirpath(struct xdr_stream *xdr, const char *pathname)
{
    const u32 pathname_len = strlen(pathname);
    __be32 *p;

    BUG_ON(pathname_len > MNTPATHLEN);
    p = xdr_reserve_space(xdr, 4 + pathname_len);
    xdr_encode_opaque(p, pathname, pathname_len);
}

static void mnt_xdr_enc_dirpath(struct rpc_rqst *req, struct xdr_stream *xdr,
                const char *dirpath)
{
    encode_mntdirpath(xdr, dirpath);
}

/*
 * RFC 1094: "A non-zero status indicates some sort of error.  In this
 * case, the status is a UNIX error number."  This can be problematic
 * if the server and client use different errno values for the same
 * error.
 *
 * However, the OpenGroup XNFS spec provides a simple mapping that is
 * independent of local errno values on the server and the client.
 */
static int decode_status(struct xdr_stream *xdr, struct mountres *res)
{
    unsigned int i;
    u32 status;
    __be32 *p;

    p = xdr_inline_decode(xdr, 4);
    if (unlikely(p == NULL))
        return -EIO;
    status = be32_to_cpup(p);

    for (i = 0; i < ARRAY_SIZE(mnt_errtbl); i++) {
        if (mnt_errtbl[i].status == status) {
            res->errno = mnt_errtbl[i].errno;
            return 0;
        }
    }

    dprintk("NFS: unrecognized MNT status code: %u\n", status);
    res->errno = -EACCES;
    return 0;
}

static int decode_fhandle(struct xdr_stream *xdr, struct mountres *res)
{
    struct nfs_fh *fh = res->fh;
    __be32 *p;

    p = xdr_inline_decode(xdr, NFS2_FHSIZE);
    if (unlikely(p == NULL))
        return -EIO;

    fh->size = NFS2_FHSIZE;
    memcpy(fh->data, p, NFS2_FHSIZE);
    return 0;
}

static int mnt_xdr_dec_mountres(struct rpc_rqst *req,
                struct xdr_stream *xdr,
                struct mountres *res)
{
    int status;

    status = decode_status(xdr, res);
    if (unlikely(status != 0 || res->errno != 0))
        return status;
    return decode_fhandle(xdr, res);
}

static int decode_fhs_status(struct xdr_stream *xdr, struct mountres *res)
{
    unsigned int i;
    u32 status;
    __be32 *p;

    p = xdr_inline_decode(xdr, 4);
    if (unlikely(p == NULL))
        return -EIO;
    status = be32_to_cpup(p);

    for (i = 0; i < ARRAY_SIZE(mnt3_errtbl); i++) {
        if (mnt3_errtbl[i].status == status) {
            res->errno = mnt3_errtbl[i].errno;
            return 0;
        }
    }

    dprintk("NFS: unrecognized MNT3 status code: %u\n", status);
    res->errno = -EACCES;
    return 0;
}

static int decode_fhandle3(struct xdr_stream *xdr, struct mountres *res)
{
    struct nfs_fh *fh = res->fh;
    u32 size;
    __be32 *p;

    p = xdr_inline_decode(xdr, 4);
    if (unlikely(p == NULL))
        return -EIO;

    size = be32_to_cpup(p);
    if (size > NFS3_FHSIZE || size == 0)
        return -EIO;

    p = xdr_inline_decode(xdr, size);
    if (unlikely(p == NULL))
        return -EIO;

    fh->size = size;
    memcpy(fh->data, p, size);
    return 0;
}

static int decode_auth_flavors(struct xdr_stream *xdr, struct mountres *res)
{
    rpc_authflavor_t *flavors = res->auth_flavors;
    unsigned int *count = res->auth_count;
    u32 entries, i;
    __be32 *p;

    if (*count == 0)
        return 0;

    p = xdr_inline_decode(xdr, 4);
    if (unlikely(p == NULL))
        return -EIO;
    entries = be32_to_cpup(p);
    dprintk("NFS: received %u auth flavors\n", entries);
    if (entries > NFS_MAX_SECFLAVORS)
        entries = NFS_MAX_SECFLAVORS;

    p = xdr_inline_decode(xdr, 4 * entries);
    if (unlikely(p == NULL))
        return -EIO;

    if (entries > *count)
        entries = *count;

    for (i = 0; i < entries; i++) {
        flavors[i] = be32_to_cpup(p++);
        dprintk("NFS:   auth flavor[%u]: %d\n", i, flavors[i]);
    }
    *count = i;

    return 0;
}

static int mnt_xdr_dec_mountres3(struct rpc_rqst *req,
                 struct xdr_stream *xdr,
                 struct mountres *res)
{
    int status;

    status = decode_fhs_status(xdr, res);
    if (unlikely(status != 0 || res->errno != 0))
        return status;
    status = decode_fhandle3(xdr, res);
    if (unlikely(status != 0)) {
        res->errno = -EBADHANDLE;
        return 0;
    }
    return decode_auth_flavors(xdr, res);
}

static struct rpc_procinfo mnt_procedures[] = {
    [MOUNTPROC_MNT] = {
        .p_proc     = MOUNTPROC_MNT,
        .p_encode   = (kxdreproc_t)mnt_xdr_enc_dirpath,
        .p_decode   = (kxdrdproc_t)mnt_xdr_dec_mountres,
        .p_arglen   = MNT_enc_dirpath_sz,
        .p_replen   = MNT_dec_mountres_sz,
        .p_statidx  = MOUNTPROC_MNT,
        .p_name     = "MOUNT",
    },
    [MOUNTPROC_UMNT] = {
        .p_proc     = MOUNTPROC_UMNT,
        .p_encode   = (kxdreproc_t)mnt_xdr_enc_dirpath,
        .p_arglen   = MNT_enc_dirpath_sz,
        .p_statidx  = MOUNTPROC_UMNT,
        .p_name     = "UMOUNT",
    },
};

static struct rpc_procinfo mnt3_procedures[] = {
    [MOUNTPROC3_MNT] = {
        .p_proc     = MOUNTPROC3_MNT,
        .p_encode   = (kxdreproc_t)mnt_xdr_enc_dirpath,
        .p_decode   = (kxdrdproc_t)mnt_xdr_dec_mountres3,
        .p_arglen   = MNT_enc_dirpath_sz,
        .p_replen   = MNT_dec_mountres3_sz,
        .p_statidx  = MOUNTPROC3_MNT,
        .p_name     = "MOUNT",
    },
    [MOUNTPROC3_UMNT] = {
        .p_proc     = MOUNTPROC3_UMNT,
        .p_encode   = (kxdreproc_t)mnt_xdr_enc_dirpath,
        .p_arglen   = MNT_enc_dirpath_sz,
        .p_statidx  = MOUNTPROC3_UMNT,
        .p_name     = "UMOUNT",
    },
};


static const struct rpc_version mnt_version1 = {
    .number     = 1,
    .nrprocs    = ARRAY_SIZE(mnt_procedures),
    .procs      = mnt_procedures,
};

static const struct rpc_version mnt_version3 = {
    .number     = 3,
    .nrprocs    = ARRAY_SIZE(mnt3_procedures),
    .procs      = mnt3_procedures,
};

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

static struct rpc_stat mnt_stats;

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