1 /*
2 * linux/fs/ioctl.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7 #include <linux/syscalls.h>
8 #include <linux/mm.h>
9 #include <linux/smp_lock.h>
10 #include <linux/capability.h>
11 #include <linux/file.h>
12 #include <linux/fs.h>
13 #include <linux/security.h>
14 #include <linux/module.h>
15 #include <linux/uaccess.h>
16
17 #include <asm/ioctls.h>
18
19 /**
20 * vfs_ioctl - call filesystem specific ioctl methods
21 * @filp: open file to invoke ioctl method on
22 * @cmd: ioctl command to execute
23 * @arg: command-specific argument for ioctl
24 *
25 * Invokes filesystem specific ->unlocked_ioctl, if one exists; otherwise
26 * invokes filesystem specific ->ioctl method. If neither method exists,
27 * returns -ENOTTY.
28 *
29 * Returns 0 on success, -errno on error.
30 */
31 long vfs_ioctl(struct file *filp, unsigned int cmd,
32 unsigned long arg)
33 {
34 int error = -ENOTTY;
35
36 if (!filp->f_op)
37 goto out;
38
39 if (filp->f_op->unlocked_ioctl) {
40 error = filp->f_op->unlocked_ioctl(filp, cmd, arg);
41 if (error == -ENOIOCTLCMD)
42 error = -EINVAL;
43 goto out;
44 } else if (filp->f_op->ioctl) {
45 lock_kernel();
46 error = filp->f_op->ioctl(filp->f_path.dentry->d_inode,
47 filp, cmd, arg);
48 unlock_kernel();
49 }
50
51 out:
52 return error;
53 }
54
55 static int ioctl_fibmap(struct file *filp, int __user *p)
56 {
57 struct address_space *mapping = filp->f_mapping;
58 int res, block;
59
60 /* do we support this mess? */
61 if (!mapping->a_ops->bmap)
62 return -EINVAL;
63 if (!capable(CAP_SYS_RAWIO))
64 return -EPERM;
65 res = get_user(block, p);
66 if (res)
67 return res;
68 lock_kernel();
69 res = mapping->a_ops->bmap(mapping, block);
70 unlock_kernel();
71 return put_user(res, p);
72 }
73
74 static int file_ioctl(struct file *filp, unsigned int cmd,
75 unsigned long arg)
76 {
77 struct inode *inode = filp->f_path.dentry->d_inode;
78 int __user *p = (int __user *)arg;
79
80 switch (cmd) {
81 case FIBMAP:
82 return ioctl_fibmap(filp, p);
83 case FIGETBSZ:
84 return put_user(inode->i_sb->s_blocksize, p);
85 case FIONREAD:
86 return put_user(i_size_read(inode) - filp->f_pos, p);
87 }
88
89 return vfs_ioctl(filp, cmd, arg);
90 }
91
92 static int ioctl_fionbio(struct file *filp, int __user *argp)
93 {
94 unsigned int flag;
95 int on, error;
96
97 error = get_user(on, argp);
98 if (error)
99 return error;
100 flag = O_NONBLOCK;
101 #ifdef __sparc__
102 /* SunOS compatibility item. */
103 if (O_NONBLOCK != O_NDELAY)
104 flag |= O_NDELAY;
105 #endif
106 if (on)
107 filp->f_flags |= flag;
108 else
109 filp->f_flags &= ~flag;
110 return error;
111 }
112
113 static int ioctl_fioasync(unsigned int fd, struct file *filp,
114 int __user *argp)
115 {
116 unsigned int flag;
117 int on, error;
118
119 error = get_user(on, argp);
120 if (error)
121 return error;
122 flag = on ? FASYNC : 0;
123
124 /* Did FASYNC state change ? */
125 if ((flag ^ filp->f_flags) & FASYNC) {
126 if (filp->f_op && filp->f_op->fasync) {
127 lock_kernel();
128 error = filp->f_op->fasync(fd, filp, on);
129 unlock_kernel();
130 } else
131 error = -ENOTTY;
132 }
133 if (error)
134 return error;
135
136 if (on)
137 filp->f_flags |= FASYNC;
138 else
139 filp->f_flags &= ~FASYNC;
140 return error;
141 }
142
143 /*
144 * When you add any new common ioctls to the switches above and below
145 * please update compat_sys_ioctl() too.
146 *
147 * do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d.
148 * It's just a simple helper for sys_ioctl and compat_sys_ioctl.
149 */
150 int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
151 unsigned long arg)
152 {
153 int error = 0;
154 int __user *argp = (int __user *)arg;
155
156 switch (cmd) {
157 case FIOCLEX:
158 set_close_on_exec(fd, 1);
159 break;
160
161 case FIONCLEX:
162 set_close_on_exec(fd, 0);
163 break;
164
165 case FIONBIO:
166 error = ioctl_fionbio(filp, argp);
167 break;
168
169 case FIOASYNC:
170 error = ioctl_fioasync(fd, filp, argp);
171 break;
172
173 case FIOQSIZE:
174 if (S_ISDIR(filp->f_path.dentry->d_inode->i_mode) ||
175 S_ISREG(filp->f_path.dentry->d_inode->i_mode) ||
176 S_ISLNK(filp->f_path.dentry->d_inode->i_mode)) {
177 loff_t res =
178 inode_get_bytes(filp->f_path.dentry->d_inode);
179 error = copy_to_user((loff_t __user *)arg, &res,
180 sizeof(res)) ? -EFAULT : 0;
181 } else
182 error = -ENOTTY;
183 break;
184 default:
185 if (S_ISREG(filp->f_path.dentry->d_inode->i_mode))
186 error = file_ioctl(filp, cmd, arg);
187 else
188 error = vfs_ioctl(filp, cmd, arg);
189 break;
190 }
191 return error;
192 }
193
194 asmlinkage long sys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg)
195 {
196 struct file *filp;
197 int error = -EBADF;
198 int fput_needed;
199
200 filp = fget_light(fd, &fput_needed);
201 if (!filp)
202 goto out;
203
204 error = security_file_ioctl(filp, cmd, arg);
205 if (error)
206 goto out_fput;
207
208 error = do_vfs_ioctl(filp, fd, cmd, arg);
209 out_fput:
210 fput_light(filp, fput_needed);
211 out:
212 return error;
213 }
214
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