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 static 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