pioctl.c

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/*
 * Pioctl operations for Coda.
 * Original version: (C) 1996 Peter Braam
 * Rewritten for Linux 2.1: (C) 1997 Carnegie Mellon University
 *
 * Carnegie Mellon encourages users of this code to contribute improvements
 * to the Coda project. Contact Peter Braam <[email protected]>.
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/namei.h>
#include <linux/module.h>
#include <asm/uaccess.h>

#include <linux/coda.h>
#include <linux/coda_psdev.h>

#include "coda_linux.h"

/* pioctl ops */
static int coda_ioctl_permission(struct inode *inode, int mask);
static long coda_pioctl(struct file *filp, unsigned int cmd,
            unsigned long user_data);

/* exported from this file */
const struct inode_operations coda_ioctl_inode_operations = {
    .permission = coda_ioctl_permission,
    .setattr    = coda_setattr,
};

const struct file_operations coda_ioctl_operations = {
    .owner      = THIS_MODULE,
    .unlocked_ioctl = coda_pioctl,
    .llseek     = noop_llseek,
};

/* the coda pioctl inode ops */
static int coda_ioctl_permission(struct inode *inode, int mask)
{
    return (mask & MAY_EXEC) ? -EACCES : 0;
}

static long coda_pioctl(struct file *filp, unsigned int cmd,
            unsigned long user_data)
{
    struct path path;
    int error;
    struct PioctlData data;
    struct inode *inode = filp->f_dentry->d_inode;
    struct inode *target_inode = NULL;
    struct coda_inode_info *cnp;

    /* get the Pioctl data arguments from user space */
    if (copy_from_user(&data, (void __user *)user_data, sizeof(data)))
        return -EINVAL;

    /*
     * Look up the pathname. Note that the pathname is in
     * user memory, and namei takes care of this
     */
    if (data.follow)
        error = user_path(data.path, &path);
    else
        error = user_lpath(data.path, &path);

    if (error)
        return error;

    target_inode = path.dentry->d_inode;

    /* return if it is not a Coda inode */
    if (target_inode->i_sb != inode->i_sb) {
        error = -EINVAL;
        goto out;
    }

    /* now proceed to make the upcall */
    cnp = ITOC(target_inode);

    error = venus_pioctl(inode->i_sb, &(cnp->c_fid), cmd, &data);
out:
    path_put(&path);
    return error;
}