fs/coda/pioctl.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Pioctl operations for Coda.
   4  * Original version: (C) 1996 Peter Braam
   5  * Rewritten for Linux 2.1: (C) 1997 Carnegie Mellon University
   6  *
   7  * Carnegie Mellon encourages users of this code to contribute improvements
   8  * to the Coda project. Contact Peter Braam <coda@cs.cmu.edu>.
   9  */
  10
  11 #include <linux/types.h>
  12 #include <linux/kernel.h>
  13 #include <linux/time.h>
  14 #include <linux/fs.h>
  15 #include <linux/stat.h>
  16 #include <linux/errno.h>
  17 #include <linux/string.h>
  18 #include <linux/namei.h>
  19 #include <linux/module.h>
  20 #include <linux/uaccess.h>
  21
  22 #include <linux/coda.h>
  23 #include <linux/coda_psdev.h>
  24
  25 #include "coda_linux.h"
  26
  27 /* pioctl ops */
  28 static int coda_ioctl_permission(struct inode *inode, int mask);
  29 static long coda_pioctl(struct file *filp, unsigned int cmd,
  30                         unsigned long user_data);
  31
  32 /* exported from this file */
  33 const struct inode_operations coda_ioctl_inode_operations = {
  34         .permission     = coda_ioctl_permission,
  35         .setattr        = coda_setattr,
  36 };
  37
  38 const struct file_operations coda_ioctl_operations = {
  39         .unlocked_ioctl = coda_pioctl,
  40         .llseek         = noop_llseek,
  41 };
  42
  43 /* the coda pioctl inode ops */
  44 static int coda_ioctl_permission(struct inode *inode, int mask)
  45 {
  46         return (mask & MAY_EXEC) ? -EACCES : 0;
  47 }
  48
  49 static long coda_pioctl(struct file *filp, unsigned int cmd,
  50                         unsigned long user_data)
  51 {
  52         struct path path;
  53         int error;
  54         struct PioctlData data;
  55         struct inode *inode = file_inode(filp);
  56         struct inode *target_inode = NULL;
  57         struct coda_inode_info *cnp;
  58
  59         /* get the Pioctl data arguments from user space */
  60         if (copy_from_user(&data, (void __user *)user_data, sizeof(data)))
  61                 return -EINVAL;
  62
  63         /*
  64          * Look up the pathname. Note that the pathname is in
  65          * user memory, and namei takes care of this
  66          */
  67         if (data.follow)
  68                 error = user_path(data.path, &path);
  69         else
  70                 error = user_lpath(data.path, &path);
  71
  72         if (error)
  73                 return error;
  74
  75         target_inode = d_inode(path.dentry);
  76
  77         /* return if it is not a Coda inode */
  78         if (target_inode->i_sb != inode->i_sb) {
  79                 error = -EINVAL;
  80                 goto out;
  81         }
  82
  83         /* now proceed to make the upcall */
  84         cnp = ITOC(target_inode);
  85
  86         error = venus_pioctl(inode->i_sb, &(cnp->c_fid), cmd, &data);
  87 out:
  88         path_put(&path);
  89         return error;
  90 }