summaryrefslogtreecommitdiffstats
path: root/fs/statfs.c
blob: 4ef021f3b6120c7534df864c120dcf9f8b9ba3a4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
#include <linux/syscalls.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/namei.h>
#include <linux/statfs.h>
#include <linux/security.h>
#include <linux/uaccess.h>

int vfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
	int retval = -ENODEV;

	if (dentry) {
		retval = -ENOSYS;
		if (dentry->d_sb->s_op->statfs) {
			memset(buf, 0, sizeof(*buf));
			retval = security_sb_statfs(dentry);
			if (retval)
				return retval;
			retval = dentry->d_sb->s_op->statfs(dentry, buf);
			if (retval == 0 && buf->f_frsize == 0)
				buf->f_frsize = buf->f_bsize;
		}
	}
	return retval;
}

EXPORT_SYMBOL(vfs_statfs);

static int vfs_statfs_native(struct dentry *dentry, struct statfs *buf)
{
	struct kstatfs st;
	int retval;

	retval = vfs_statfs(dentry, &st);
	if (retval)
		return retval;

	if (sizeof(*buf) == sizeof(st))
		memcpy(buf, &st, sizeof(st));
	else {
		if (sizeof buf->f_blocks == 4) {
			if ((st.f_blocks | st.f_bfree | st.f_bavail |
			     st.f_bsize | st.f_frsize) &
			    0xffffffff00000000ULL)
				return -EOVERFLOW;
			/*
			 * f_files and f_ffree may be -1; it's okay to stuff
			 * that into 32 bits
			 */
			if (st.f_files != -1 &&
			    (st.f_files & 0xffffffff00000000ULL))
				return -EOVERFLOW;
			if (st.f_ffree != -1 &&
			    (st.f_ffree & 0xffffffff00000000ULL))
				return -EOVERFLOW;
		}

		buf->f_type = st.f_type;
		buf->f_bsize = st.f_bsize;
		buf->f_blocks = st.f_blocks;
		buf->f_bfree = st.f_bfree;
		buf->f_bavail = st.f_bavail;
		buf->f_files = st.f_files;
		buf->f_ffree = st.f_ffree;
		buf->f_fsid = st.f_fsid;
		buf->f_namelen = st.f_namelen;
		buf->f_frsize = st.f_frsize;
		memset(buf->f_spare, 0, sizeof(buf->f_spare));
	}
	return 0;
}

static int vfs_statfs64(struct dentry *dentry, struct statfs64 *buf)
{
	struct kstatfs st;
	int retval;

	retval = vfs_statfs(dentry, &st);
	if (retval)
		return retval;

	if (sizeof(*buf) == sizeof(st))
		memcpy(buf, &st, sizeof(st));
	else {
		buf->f_type = st.f_type;
		buf->f_bsize = st.f_bsize;
		buf->f_blocks = st.f_blocks;
		buf->f_bfree = st.f_bfree;
		buf->f_bavail = st.f_bavail;
		buf->f_files = st.f_files;
		buf->f_ffree = st.f_ffree;
		buf->f_fsid = st.f_fsid;
		buf->f_namelen = st.f_namelen;
		buf->f_frsize = st.f_frsize;
		memset(buf->f_spare, 0, sizeof(buf->f_spare));
	}
	return 0;
}

SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct statfs __user *, buf)
{
	struct path path;
	int error;

	error = user_path(pathname, &path);
	if (!error) {
		struct statfs tmp;
		error = vfs_statfs_native(path.dentry, &tmp);
		if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
			error = -EFAULT;
		path_put(&path);
	}
	return error;
}

SYSCALL_DEFINE3(statfs64, const char __user *, pathname, size_t, sz, struct statfs64 __user *, buf)
{
	struct path path;
	long error;

	if (sz != sizeof(*buf))
		return -EINVAL;
	error = user_path(pathname, &path);
	if (!error) {
		struct statfs64 tmp;
		error = vfs_statfs64(path.dentry, &tmp);
		if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
			error = -EFAULT;
		path_put(&path);
	}
	return error;
}

SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf)
{
	struct file *file;
	struct statfs tmp;
	int error;

	error = -EBADF;
	file = fget(fd);
	if (!file)
		goto out;
	error = vfs_statfs_native(file->f_path.dentry, &tmp);
	if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
		error = -EFAULT;
	fput(file);
out:
	return error;
}

SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user *, buf)
{
	struct file *file;
	struct statfs64 tmp;
	int error;

	if (sz != sizeof(*buf))
		return -EINVAL;

	error = -EBADF;
	file = fget(fd);
	if (!file)
		goto out;
	error = vfs_statfs64(file->f_path.dentry, &tmp);
	if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
		error = -EFAULT;
	fput(file);
out:
	return error;
}

SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
{
	struct super_block *s;
	struct ustat tmp;
	struct kstatfs sbuf;
	int err;

	s = user_get_super(new_decode_dev(dev));
	if (!s)
		return -EINVAL;

	err = vfs_statfs(s->s_root, &sbuf);
	drop_super(s);
	if (err)
		return err;

	memset(&tmp,0,sizeof(struct ustat));
	tmp.f_tfree = sbuf.f_bfree;
	tmp.f_tinode = sbuf.f_ffree;

	return copy_to_user(ubuf, &tmp, sizeof(struct ustat)) ? -EFAULT : 0;
}