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/*

 *  linux/fs/nfs/symlink.c

 *

 *  Copyright (C) 1992  Rick Sladkey

 *

 *  Optimization changes Copyright (C) 1994 Florian La Roche

 *

 *  nfs symlink handling code

 */

#include <linux/sched.h>

#include <linux/errno.h>

#include <linux/nfs_fs.h>

#include <linux/stat.h>

#include <linux/mm.h>

#include <linux/malloc.h>

#include <linux/string.h>

#include <asm/segment.h>

static int nfs_readlink(struct inode *, char *, int);

static int nfs_follow_link(struct inode *, struct inode *, int, int,

                           struct inode **);

/*

 * symlinks can't do much...

 */

struct inode_operations nfs_symlink_inode_operations = {

        NULL,                   /* no file-operations */

        NULL,                   /* create */

        NULL,                   /* lookup */

        NULL,                   /* link */

        NULL,                   /* unlink */

        NULL,                   /* symlink */

        NULL,                   /* mkdir */

        NULL,                   /* rmdir */

        NULL,                   /* mknod */

        NULL,                   /* rename */

        nfs_readlink,           /* readlink */

        nfs_follow_link,        /* follow_link */

        NULL,                   /* readpage */

        NULL,                   /* writepage */

        NULL,                   /* bmap */

        NULL,                   /* truncate */

        NULL                    /* permission */

};

static int nfs_follow_link(struct inode *dir, struct inode *inode,

                           int flag, int mode, struct inode **res_inode)

{

        int error, *mem;

        unsigned int len;

        char *res, *res2;

        *res_inode = NULL;

        if (!dir) {

                dir = current->fs->root;

                dir->i_count++;

        }

        if (!inode) {

                iput(dir);

                return -ENOENT;

        }

        if (!S_ISLNK(inode->i_mode)) {

                iput(dir);

                *res_inode = inode;

                return 0;

        }

        if (current->link_count > 5) {

                iput(inode);

                iput(dir);

                return -ELOOP;

        }

        error = nfs_proc_readlink(NFS_SERVER(inode), NFS_FH(inode), &mem,

                &res, &len, NFS_MAXPATHLEN);

        if (error) {

                iput(inode);

                iput(dir);

                kfree(mem);

                return error;

        }

        while ((res2 = (char *) kmalloc(NFS_MAXPATHLEN + 1, GFP_NFS)) == NULL) {

                schedule();

        }

        memcpy(res2, res, len);

        res2[len] = '\0';

        kfree(mem);

        iput(inode);

        current->link_count++;

        error = open_namei(res2, flag, mode, res_inode, dir);

        current->link_count--;

        kfree_s(res2, NFS_MAXPATHLEN + 1);

        return error;

}

static int nfs_readlink(struct inode *inode, char *buffer, int buflen)

{

        int error, *mem;

        unsigned int len;

        char *res;

        if (!S_ISLNK(inode->i_mode)) {

                iput(inode);

                return -EINVAL;

        }

        if (buflen > NFS_MAXPATHLEN)

                buflen = NFS_MAXPATHLEN;

        error = nfs_proc_readlink(NFS_SERVER(inode), NFS_FH(inode), &mem,

                &res, &len, buflen);

        iput(inode);

        if (! error) {

                memcpy_tofs(buffer, res, len);

                put_user('\0', buffer + len);

                error = len;

        }

        kfree(mem);

        return error;

}