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/*

 *  linux/fs/sysv/symlink.c

 *

 *  minix/symlink.c

 *  Copyright (C) 1991, 1992  Linus Torvalds

 *

 *  coh/symlink.c

 *  Copyright (C) 1993  Pascal Haible, Bruno Haible

 *

 *  sysv/symlink.c

 *  Copyright (C) 1993  Bruno Haible

 *

 *  SystemV/Coherent symlink handling code

 */

#include <linux/errno.h>

#include <linux/sched.h>

#include <linux/sysv_fs.h>

#include <linux/stat.h>

#include <asm/segment.h>

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

static int sysv_follow_link(struct inode *, struct inode *, int, int, struct inode **);

/*

 * symlinks can't do much...

 */

struct inode_operations sysv_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 */

        sysv_readlink,          /* readlink */

        sysv_follow_link,       /* follow_link */

        NULL,                   /* readpage */

        NULL,                   /* writepage */

        NULL,                   /* bmap */

        NULL,                   /* truncate */

        NULL                    /* permission */

};

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

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

{

        int error;

        struct buffer_head * bh;

        *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;

        }

        if (!(bh = sysv_file_bread(inode, 0, 0))) { /* is reading 1 block enough ?? */

                iput(inode);

                iput(dir);

                return -EIO;

        }

        iput(inode);

        current->link_count++;

        error = open_namei(bh->b_data,flag,mode,res_inode,dir);

        current->link_count--;

        brelse(bh);

        return error;

}

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

{

        struct buffer_head * bh;

        char * bh_data;

        int i;

        char c;

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

                iput(inode);

                return -EINVAL;

        }

        if (buflen > inode->i_sb->sv_block_size_1)

                buflen = inode->i_sb->sv_block_size_1;

        bh = sysv_file_bread(inode, 0, 0);

        iput(inode);

        if (!bh)

                return 0;

        bh_data = bh->b_data;

        i = 0;

        while (i<buflen && (c = bh_data[i])) {

                i++;

                put_user(c,buffer++);

        }

        brelse(bh);

        return i;

}