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 */
coda_ioctl_permission(struct inode * inode,int mask)44 static int coda_ioctl_permission(struct inode *inode, int mask)
45 {
46 	return (mask & MAY_EXEC) ? -EACCES : 0;
47 }
48 
coda_pioctl(struct file * filp,unsigned int cmd,unsigned long user_data)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 }
91