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 "coda_psdev.h"
  24 #include "coda_linux.h"
  25
  26 /* pioctl ops */
  27 static int coda_ioctl_permission(struct inode *inode, int mask);
  28 static long coda_pioctl(struct file *filp, unsigned int cmd,
  29                         unsigned long user_data);
  30
  31 /* exported from this file */
  32 const struct inode_operations coda_ioctl_inode_operations = {
  33         .permission     = coda_ioctl_permission,
  34         .setattr        = coda_setattr,
  35 };
  36
  37 const struct file_operations coda_ioctl_operations = {
  38         .unlocked_ioctl = coda_pioctl,
  39         .llseek         = noop_llseek,
  40 };
  41
  42 /* the coda pioctl inode ops */
  43 static int coda_ioctl_permission(struct inode *inode, int mask)
  44 {
  45         return (mask & MAY_EXEC) ? -EACCES : 0;
  46 }
  47
  48 static long coda_pioctl(struct file *filp, unsigned int cmd,
  49                         unsigned long user_data)
  50 {
  51         struct path path;
  52         int error;
  53         struct PioctlData data;
  54         struct inode *inode = file_inode(filp);
  55         struct inode *target_inode = NULL;
  56         struct coda_inode_info *cnp;
  57
  58         /* get the Pioctl data arguments from user space */
  59         if (copy_from_user(&data, (void __user *)user_data, sizeof(data)))
  60                 return -EINVAL;
  61
  62         /*
  63          * Look up the pathname. Note that the pathname is in
  64          * user memory, and namei takes care of this
  65          */
  66         error = user_path_at(AT_FDCWD, data.path,
  67                              data.follow ? LOOKUP_FOLLOW : 0, &path);
  68         if (error)
  69                 return error;
  70
  71         target_inode = d_inode(path.dentry);
  72
  73         /* return if it is not a Coda inode */
  74         if (target_inode->i_sb != inode->i_sb) {
  75                 error = -EINVAL;
  76                 goto out;
  77         }
  78
  79         /* now proceed to make the upcall */
  80         cnp = ITOC(target_inode);
  81
  82         error = venus_pioctl(inode->i_sb, &(cnp->c_fid), cmd, &data);
  83 out:
  84         path_put(&path);
  85         return error;
  86 }