xref: /openbmc/linux/fs/ext2/ioctl.c (revision 14f9f7b2)
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/smp_lock.h>
16 #include <asm/current.h>
17 #include <asm/uaccess.h>
18 
19 
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 
27 	ext2_debug ("cmd = %u, arg = %lu\n", cmd, arg);
28 
29 	switch (cmd) {
30 	case EXT2_IOC_GETFLAGS:
31 		ext2_get_inode_flags(ei);
32 		flags = ei->i_flags & EXT2_FL_USER_VISIBLE;
33 		return put_user(flags, (int __user *) arg);
34 	case EXT2_IOC_SETFLAGS: {
35 		unsigned int oldflags;
36 
37 		if (IS_RDONLY(inode))
38 			return -EROFS;
39 
40 		if (!is_owner_or_cap(inode))
41 			return -EACCES;
42 
43 		if (get_user(flags, (int __user *) arg))
44 			return -EFAULT;
45 
46 		if (!S_ISDIR(inode->i_mode))
47 			flags &= ~EXT2_DIRSYNC_FL;
48 
49 		mutex_lock(&inode->i_mutex);
50 		/* Is it quota file? Do not allow user to mess with it */
51 		if (IS_NOQUOTA(inode)) {
52 			mutex_unlock(&inode->i_mutex);
53 			return -EPERM;
54 		}
55 		oldflags = ei->i_flags;
56 
57 		/*
58 		 * The IMMUTABLE and APPEND_ONLY flags can only be changed by
59 		 * the relevant capability.
60 		 *
61 		 * This test looks nicer. Thanks to Pauline Middelink
62 		 */
63 		if ((flags ^ oldflags) & (EXT2_APPEND_FL | EXT2_IMMUTABLE_FL)) {
64 			if (!capable(CAP_LINUX_IMMUTABLE)) {
65 				mutex_unlock(&inode->i_mutex);
66 				return -EPERM;
67 			}
68 		}
69 
70 		flags = flags & EXT2_FL_USER_MODIFIABLE;
71 		flags |= oldflags & ~EXT2_FL_USER_MODIFIABLE;
72 		ei->i_flags = flags;
73 		mutex_unlock(&inode->i_mutex);
74 
75 		ext2_set_inode_flags(inode);
76 		inode->i_ctime = CURRENT_TIME_SEC;
77 		mark_inode_dirty(inode);
78 		return 0;
79 	}
80 	case EXT2_IOC_GETVERSION:
81 		return put_user(inode->i_generation, (int __user *) arg);
82 	case EXT2_IOC_SETVERSION:
83 		if (!is_owner_or_cap(inode))
84 			return -EPERM;
85 		if (IS_RDONLY(inode))
86 			return -EROFS;
87 		if (get_user(inode->i_generation, (int __user *) arg))
88 			return -EFAULT;
89 		inode->i_ctime = CURRENT_TIME_SEC;
90 		mark_inode_dirty(inode);
91 		return 0;
92 	case EXT2_IOC_GETRSVSZ:
93 		if (test_opt(inode->i_sb, RESERVATION)
94 			&& S_ISREG(inode->i_mode)
95 			&& ei->i_block_alloc_info) {
96 			rsv_window_size = ei->i_block_alloc_info->rsv_window_node.rsv_goal_size;
97 			return put_user(rsv_window_size, (int __user *)arg);
98 		}
99 		return -ENOTTY;
100 	case EXT2_IOC_SETRSVSZ: {
101 
102 		if (!test_opt(inode->i_sb, RESERVATION) ||!S_ISREG(inode->i_mode))
103 			return -ENOTTY;
104 
105 		if (IS_RDONLY(inode))
106 			return -EROFS;
107 
108 		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
109 			return -EACCES;
110 
111 		if (get_user(rsv_window_size, (int __user *)arg))
112 			return -EFAULT;
113 
114 		if (rsv_window_size > EXT2_MAX_RESERVE_BLOCKS)
115 			rsv_window_size = EXT2_MAX_RESERVE_BLOCKS;
116 
117 		/*
118 		 * need to allocate reservation structure for this inode
119 		 * before set the window size
120 		 */
121 		/*
122 		 * XXX What lock should protect the rsv_goal_size?
123 		 * Accessed in ext2_get_block only.  ext3 uses i_truncate.
124 		 */
125 		mutex_lock(&ei->truncate_mutex);
126 		if (!ei->i_block_alloc_info)
127 			ext2_init_block_alloc_info(inode);
128 
129 		if (ei->i_block_alloc_info){
130 			struct ext2_reserve_window_node *rsv = &ei->i_block_alloc_info->rsv_window_node;
131 			rsv->rsv_goal_size = rsv_window_size;
132 		}
133 		mutex_unlock(&ei->truncate_mutex);
134 		return 0;
135 	}
136 	default:
137 		return -ENOTTY;
138 	}
139 }
140 
141 #ifdef CONFIG_COMPAT
142 long ext2_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
143 {
144 	/* These are just misnamed, they actually get/put from/to user an int */
145 	switch (cmd) {
146 	case EXT2_IOC32_GETFLAGS:
147 		cmd = EXT2_IOC_GETFLAGS;
148 		break;
149 	case EXT2_IOC32_SETFLAGS:
150 		cmd = EXT2_IOC_SETFLAGS;
151 		break;
152 	case EXT2_IOC32_GETVERSION:
153 		cmd = EXT2_IOC_GETVERSION;
154 		break;
155 	case EXT2_IOC32_SETVERSION:
156 		cmd = EXT2_IOC_SETVERSION;
157 		break;
158 	default:
159 		return -ENOIOCTLCMD;
160 	}
161 	return ext2_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
162 }
163 #endif
164