sysfs: Allow removal of symlinks in the sysfs root
[linux-2.6] / fs / jfs / ioctl.c
1 /*
2  * linux/fs/jfs/ioctl.c
3  *
4  * Copyright (C) 2006 Herbert Poetzl
5  * adapted from Remy Card's ext2/ioctl.c
6  */
7
8 #include <linux/fs.h>
9 #include <linux/ctype.h>
10 #include <linux/capability.h>
11 #include <linux/time.h>
12 #include <linux/sched.h>
13 #include <asm/current.h>
14 #include <asm/uaccess.h>
15
16 #include "jfs_incore.h"
17 #include "jfs_dinode.h"
18 #include "jfs_inode.h"
19
20
21 static struct {
22         long jfs_flag;
23         long ext2_flag;
24 } jfs_map[] = {
25         {JFS_NOATIME_FL,        FS_NOATIME_FL},
26         {JFS_DIRSYNC_FL,        FS_DIRSYNC_FL},
27         {JFS_SYNC_FL,           FS_SYNC_FL},
28         {JFS_SECRM_FL,          FS_SECRM_FL},
29         {JFS_UNRM_FL,           FS_UNRM_FL},
30         {JFS_APPEND_FL,         FS_APPEND_FL},
31         {JFS_IMMUTABLE_FL,      FS_IMMUTABLE_FL},
32         {0, 0},
33 };
34
35 static long jfs_map_ext2(unsigned long flags, int from)
36 {
37         int index=0;
38         long mapped=0;
39
40         while (jfs_map[index].jfs_flag) {
41                 if (from) {
42                         if (jfs_map[index].ext2_flag & flags)
43                                 mapped |= jfs_map[index].jfs_flag;
44                 } else {
45                         if (jfs_map[index].jfs_flag & flags)
46                                 mapped |= jfs_map[index].ext2_flag;
47                 }
48                 index++;
49         }
50         return mapped;
51 }
52
53
54 long jfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
55 {
56         struct inode *inode = filp->f_dentry->d_inode;
57         struct jfs_inode_info *jfs_inode = JFS_IP(inode);
58         unsigned int flags;
59
60         switch (cmd) {
61         case JFS_IOC_GETFLAGS:
62                 jfs_get_inode_flags(jfs_inode);
63                 flags = jfs_inode->mode2 & JFS_FL_USER_VISIBLE;
64                 flags = jfs_map_ext2(flags, 0);
65                 return put_user(flags, (int __user *) arg);
66         case JFS_IOC_SETFLAGS: {
67                 unsigned int oldflags;
68
69                 if (IS_RDONLY(inode))
70                         return -EROFS;
71
72                 if (!is_owner_or_cap(inode))
73                         return -EACCES;
74
75                 if (get_user(flags, (int __user *) arg))
76                         return -EFAULT;
77
78                 flags = jfs_map_ext2(flags, 1);
79                 if (!S_ISDIR(inode->i_mode))
80                         flags &= ~JFS_DIRSYNC_FL;
81
82                 /* Is it quota file? Do not allow user to mess with it */
83                 if (IS_NOQUOTA(inode))
84                         return -EPERM;
85
86                 /* Lock against other parallel changes of flags */
87                 mutex_lock(&inode->i_mutex);
88
89                 jfs_get_inode_flags(jfs_inode);
90                 oldflags = jfs_inode->mode2;
91
92                 /*
93                  * The IMMUTABLE and APPEND_ONLY flags can only be changed by
94                  * the relevant capability.
95                  */
96                 if ((oldflags & JFS_IMMUTABLE_FL) ||
97                         ((flags ^ oldflags) &
98                         (JFS_APPEND_FL | JFS_IMMUTABLE_FL))) {
99                         if (!capable(CAP_LINUX_IMMUTABLE)) {
100                                 mutex_unlock(&inode->i_mutex);
101                                 return -EPERM;
102                         }
103                 }
104
105                 flags = flags & JFS_FL_USER_MODIFIABLE;
106                 flags |= oldflags & ~JFS_FL_USER_MODIFIABLE;
107                 jfs_inode->mode2 = flags;
108
109                 jfs_set_inode_flags(inode);
110                 mutex_unlock(&inode->i_mutex);
111                 inode->i_ctime = CURRENT_TIME_SEC;
112                 mark_inode_dirty(inode);
113                 return 0;
114         }
115         default:
116                 return -ENOTTY;
117         }
118 }
119
120 #ifdef CONFIG_COMPAT
121 long jfs_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
122 {
123         /* While these ioctl numbers defined with 'long' and have different
124          * numbers than the 64bit ABI,
125          * the actual implementation only deals with ints and is compatible.
126          */
127         switch (cmd) {
128         case JFS_IOC_GETFLAGS32:
129                 cmd = JFS_IOC_GETFLAGS;
130                 break;
131         case JFS_IOC_SETFLAGS32:
132                 cmd = JFS_IOC_SETFLAGS;
133                 break;
134         }
135         return jfs_ioctl(filp, cmd, arg);
136 }
137 #endif