1 /*
2  * linux/fs/ext2/ioctl.c
3  *
4  * Copyright (C) 1993, 1994, 1995
5  * Remy Card (card@masi.ibp.fr)
6  * Laboratoire MASI - Institut Blaise Pascal
7  * Universite Pierre et Marie Curie (Paris VI)
8  */
9 
10 #include "ext2.h"
11 #include <linux/capability.h>
12 #include <linux/time.h>
13 #include <linux/sched.h>
14 #include <linux/compat.h>
15 #include <linux/mount.h>
16 #include <asm/current.h>
17 #include <asm/uaccess.h>
18 
19 
ext2_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)20 long ext2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
21 {
22 	struct inode *inode = filp->f_dentry->d_inode;
23 	struct ext2_inode_info *ei = EXT2_I(inode);
24 	unsigned int flags;
25 	unsigned short rsv_window_size;
26 	int ret;
27 
28 	ext2_debug ("cmd = %u, arg = %lu\n", cmd, arg);
29 
30 	switch (cmd) {
31 	case EXT2_IOC_GETFLAGS:
32 		ext2_get_inode_flags(ei);
33 		flags = ei->i_flags & EXT2_FL_USER_VISIBLE;
34 		return put_user(flags, (int __user *) arg);
35 	case EXT2_IOC_SETFLAGS: {
36 		unsigned int oldflags;
37 
38 		ret = mnt_want_write_file(filp);
39 		if (ret)
40 			return ret;
41 
42 		if (!inode_owner_or_capable(inode)) {
43 			ret = -EACCES;
44 			goto setflags_out;
45 		}
46 
47 		if (get_user(flags, (int __user *) arg)) {
48 			ret = -EFAULT;
49 			goto setflags_out;
50 		}
51 
52 		flags = ext2_mask_flags(inode->i_mode, flags);
53 
54 		mutex_lock(&inode->i_mutex);
55 		/* Is it quota file? Do not allow user to mess with it */
56 		if (IS_NOQUOTA(inode)) {
57 			mutex_unlock(&inode->i_mutex);
58 			ret = -EPERM;
59 			goto setflags_out;
60 		}
61 		oldflags = ei->i_flags;
62 
63 		/*
64 		 * The IMMUTABLE and APPEND_ONLY flags can only be changed by
65 		 * the relevant capability.
66 		 *
67 		 * This test looks nicer. Thanks to Pauline Middelink
68 		 */
69 		if ((flags ^ oldflags) & (EXT2_APPEND_FL | EXT2_IMMUTABLE_FL)) {
70 			if (!capable(CAP_LINUX_IMMUTABLE)) {
71 				mutex_unlock(&inode->i_mutex);
72 				ret = -EPERM;
73 				goto setflags_out;
74 			}
75 		}
76 
77 		flags = flags & EXT2_FL_USER_MODIFIABLE;
78 		flags |= oldflags & ~EXT2_FL_USER_MODIFIABLE;
79 		ei->i_flags = flags;
80 
81 		ext2_set_inode_flags(inode);
82 		inode->i_ctime = CURRENT_TIME_SEC;
83 		mutex_unlock(&inode->i_mutex);
84 
85 		mark_inode_dirty(inode);
86 setflags_out:
87 		mnt_drop_write_file(filp);
88 		return ret;
89 	}
90 	case EXT2_IOC_GETVERSION:
91 		return put_user(inode->i_generation, (int __user *) arg);
92 	case EXT2_IOC_SETVERSION: {
93 		__u32 generation;
94 
95 		if (!inode_owner_or_capable(inode))
96 			return -EPERM;
97 		ret = mnt_want_write_file(filp);
98 		if (ret)
99 			return ret;
100 		if (get_user(generation, (int __user *) arg)) {
101 			ret = -EFAULT;
102 			goto setversion_out;
103 		}
104 
105 		mutex_lock(&inode->i_mutex);
106 		inode->i_ctime = CURRENT_TIME_SEC;
107 		inode->i_generation = generation;
108 		mutex_unlock(&inode->i_mutex);
109 
110 		mark_inode_dirty(inode);
111 setversion_out:
112 		mnt_drop_write_file(filp);
113 		return ret;
114 	}
115 	case EXT2_IOC_GETRSVSZ:
116 		if (test_opt(inode->i_sb, RESERVATION)
117 			&& S_ISREG(inode->i_mode)
118 			&& ei->i_block_alloc_info) {
119 			rsv_window_size = ei->i_block_alloc_info->rsv_window_node.rsv_goal_size;
120 			return put_user(rsv_window_size, (int __user *)arg);
121 		}
122 		return -ENOTTY;
123 	case EXT2_IOC_SETRSVSZ: {
124 
125 		if (!test_opt(inode->i_sb, RESERVATION) ||!S_ISREG(inode->i_mode))
126 			return -ENOTTY;
127 
128 		if (!inode_owner_or_capable(inode))
129 			return -EACCES;
130 
131 		if (get_user(rsv_window_size, (int __user *)arg))
132 			return -EFAULT;
133 
134 		ret = mnt_want_write_file(filp);
135 		if (ret)
136 			return ret;
137 
138 		if (rsv_window_size > EXT2_MAX_RESERVE_BLOCKS)
139 			rsv_window_size = EXT2_MAX_RESERVE_BLOCKS;
140 
141 		/*
142 		 * need to allocate reservation structure for this inode
143 		 * before set the window size
144 		 */
145 		/*
146 		 * XXX What lock should protect the rsv_goal_size?
147 		 * Accessed in ext2_get_block only.  ext3 uses i_truncate.
148 		 */
149 		mutex_lock(&ei->truncate_mutex);
150 		if (!ei->i_block_alloc_info)
151 			ext2_init_block_alloc_info(inode);
152 
153 		if (ei->i_block_alloc_info){
154 			struct ext2_reserve_window_node *rsv = &ei->i_block_alloc_info->rsv_window_node;
155 			rsv->rsv_goal_size = rsv_window_size;
156 		}
157 		mutex_unlock(&ei->truncate_mutex);
158 		mnt_drop_write_file(filp);
159 		return 0;
160 	}
161 	default:
162 		return -ENOTTY;
163 	}
164 }
165 
166 #ifdef CONFIG_COMPAT
ext2_compat_ioctl(struct file * file,unsigned int cmd,unsigned long arg)167 long ext2_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
168 {
169 	/* These are just misnamed, they actually get/put from/to user an int */
170 	switch (cmd) {
171 	case EXT2_IOC32_GETFLAGS:
172 		cmd = EXT2_IOC_GETFLAGS;
173 		break;
174 	case EXT2_IOC32_SETFLAGS:
175 		cmd = EXT2_IOC_SETFLAGS;
176 		break;
177 	case EXT2_IOC32_GETVERSION:
178 		cmd = EXT2_IOC_GETVERSION;
179 		break;
180 	case EXT2_IOC32_SETVERSION:
181 		cmd = EXT2_IOC_SETVERSION;
182 		break;
183 	default:
184 		return -ENOIOCTLCMD;
185 	}
186 	return ext2_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
187 }
188 #endif
189