text: // SPDX-License-Identifier: GPL-2.0
  /*
   * 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 <coda@cs.cmu.edu>.
   */
  
  #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 <linux/uaccess.h>
  
  #include <linux/coda.h>
  #include "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 = {
  	.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 = file_inode(filp);
  	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
  	 */
  	error = user_path_at(AT_FDCWD, data.path,
  			     data.follow ? LOOKUP_FOLLOW : 0, &path);
  	if (error)
  		return error;
  
  	target_inode = d_inode(path.dentry);
  
  	/* 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;
  }
  