xref: /openbmc/linux/fs/ioctl.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 /*
2  *  linux/fs/ioctl.c
3  *
4  *  Copyright (C) 1991, 1992  Linus Torvalds
5  */
6 
7 #include <linux/config.h>
8 #include <linux/syscalls.h>
9 #include <linux/mm.h>
10 #include <linux/smp_lock.h>
11 #include <linux/file.h>
12 #include <linux/fs.h>
13 #include <linux/security.h>
14 #include <linux/module.h>
15 
16 #include <asm/uaccess.h>
17 #include <asm/ioctls.h>
18 
19 static long do_ioctl(struct file *filp, unsigned int cmd,
20 		unsigned long arg)
21 {
22 	int error = -ENOTTY;
23 
24 	if (!filp->f_op)
25 		goto out;
26 
27 	if (filp->f_op->unlocked_ioctl) {
28 		error = filp->f_op->unlocked_ioctl(filp, cmd, arg);
29 		if (error == -ENOIOCTLCMD)
30 			error = -EINVAL;
31 		goto out;
32 	} else if (filp->f_op->ioctl) {
33 		lock_kernel();
34 		error = filp->f_op->ioctl(filp->f_dentry->d_inode,
35 					  filp, cmd, arg);
36 		unlock_kernel();
37 	}
38 
39  out:
40 	return error;
41 }
42 
43 static int file_ioctl(struct file *filp, unsigned int cmd,
44 		unsigned long arg)
45 {
46 	int error;
47 	int block;
48 	struct inode * inode = filp->f_dentry->d_inode;
49 	int __user *p = (int __user *)arg;
50 
51 	switch (cmd) {
52 		case FIBMAP:
53 		{
54 			struct address_space *mapping = filp->f_mapping;
55 			int res;
56 			/* do we support this mess? */
57 			if (!mapping->a_ops->bmap)
58 				return -EINVAL;
59 			if (!capable(CAP_SYS_RAWIO))
60 				return -EPERM;
61 			if ((error = get_user(block, p)) != 0)
62 				return error;
63 
64 			lock_kernel();
65 			res = mapping->a_ops->bmap(mapping, block);
66 			unlock_kernel();
67 			return put_user(res, p);
68 		}
69 		case FIGETBSZ:
70 			if (inode->i_sb == NULL)
71 				return -EBADF;
72 			return put_user(inode->i_sb->s_blocksize, p);
73 		case FIONREAD:
74 			return put_user(i_size_read(inode) - filp->f_pos, p);
75 	}
76 
77 	return do_ioctl(filp, cmd, arg);
78 }
79 
80 /*
81  * When you add any new common ioctls to the switches above and below
82  * please update compat_sys_ioctl() too.
83  *
84  * vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d.
85  * It's just a simple helper for sys_ioctl and compat_sys_ioctl.
86  */
87 int vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd, unsigned long arg)
88 {
89 	unsigned int flag;
90 	int on, error = 0;
91 
92 	switch (cmd) {
93 		case FIOCLEX:
94 			set_close_on_exec(fd, 1);
95 			break;
96 
97 		case FIONCLEX:
98 			set_close_on_exec(fd, 0);
99 			break;
100 
101 		case FIONBIO:
102 			if ((error = get_user(on, (int __user *)arg)) != 0)
103 				break;
104 			flag = O_NONBLOCK;
105 #ifdef __sparc__
106 			/* SunOS compatibility item. */
107 			if(O_NONBLOCK != O_NDELAY)
108 				flag |= O_NDELAY;
109 #endif
110 			if (on)
111 				filp->f_flags |= flag;
112 			else
113 				filp->f_flags &= ~flag;
114 			break;
115 
116 		case FIOASYNC:
117 			if ((error = get_user(on, (int __user *)arg)) != 0)
118 				break;
119 			flag = on ? FASYNC : 0;
120 
121 			/* Did FASYNC state change ? */
122 			if ((flag ^ filp->f_flags) & FASYNC) {
123 				if (filp->f_op && filp->f_op->fasync) {
124 					lock_kernel();
125 					error = filp->f_op->fasync(fd, filp, on);
126 					unlock_kernel();
127 				}
128 				else error = -ENOTTY;
129 			}
130 			if (error != 0)
131 				break;
132 
133 			if (on)
134 				filp->f_flags |= FASYNC;
135 			else
136 				filp->f_flags &= ~FASYNC;
137 			break;
138 
139 		case FIOQSIZE:
140 			if (S_ISDIR(filp->f_dentry->d_inode->i_mode) ||
141 			    S_ISREG(filp->f_dentry->d_inode->i_mode) ||
142 			    S_ISLNK(filp->f_dentry->d_inode->i_mode)) {
143 				loff_t res = inode_get_bytes(filp->f_dentry->d_inode);
144 				error = copy_to_user((loff_t __user *)arg, &res, sizeof(res)) ? -EFAULT : 0;
145 			}
146 			else
147 				error = -ENOTTY;
148 			break;
149 		default:
150 			if (S_ISREG(filp->f_dentry->d_inode->i_mode))
151 				error = file_ioctl(filp, cmd, arg);
152 			else
153 				error = do_ioctl(filp, cmd, arg);
154 			break;
155 	}
156 	return error;
157 }
158 
159 asmlinkage long sys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg)
160 {
161 	struct file * filp;
162 	int error = -EBADF;
163 	int fput_needed;
164 
165 	filp = fget_light(fd, &fput_needed);
166 	if (!filp)
167 		goto out;
168 
169 	error = security_file_ioctl(filp, cmd, arg);
170 	if (error)
171 		goto out_fput;
172 
173 	error = vfs_ioctl(filp, fd, cmd, arg);
174  out_fput:
175 	fput_light(filp, fput_needed);
176  out:
177 	return error;
178 }
179 
180 /*
181  * Platforms implementing 32 bit compatibility ioctl handlers in
182  * modules need this exported
183  */
184 #ifdef CONFIG_COMPAT
185 EXPORT_SYMBOL(sys_ioctl);
186 #endif
187