1#include <linux/syscalls.h>
2#include <linux/export.h>
3#include <linux/fs.h>
4#include <linux/file.h>
5#include <linux/mount.h>
6#include <linux/namei.h>
7#include <linux/statfs.h>
8#include <linux/security.h>
9#include <linux/uaccess.h>
10#include "internal.h"
11
12static int flags_by_mnt(int mnt_flags)
13{
14 int flags = 0;
15
16 if (mnt_flags & MNT_READONLY)
17 flags |= ST_RDONLY;
18 if (mnt_flags & MNT_NOSUID)
19 flags |= ST_NOSUID;
20 if (mnt_flags & MNT_NODEV)
21 flags |= ST_NODEV;
22 if (mnt_flags & MNT_NOEXEC)
23 flags |= ST_NOEXEC;
24 if (mnt_flags & MNT_NOATIME)
25 flags |= ST_NOATIME;
26 if (mnt_flags & MNT_NODIRATIME)
27 flags |= ST_NODIRATIME;
28 if (mnt_flags & MNT_RELATIME)
29 flags |= ST_RELATIME;
30 return flags;
31}
32
33static int flags_by_sb(int s_flags)
34{
35 int flags = 0;
36 if (s_flags & MS_SYNCHRONOUS)
37 flags |= ST_SYNCHRONOUS;
38 if (s_flags & MS_MANDLOCK)
39 flags |= ST_MANDLOCK;
40 return flags;
41}
42
43static int calculate_f_flags(struct vfsmount *mnt)
44{
45 return ST_VALID | flags_by_mnt(mnt->mnt_flags) |
46 flags_by_sb(mnt->mnt_sb->s_flags);
47}
48
49static int statfs_by_dentry(struct dentry *dentry, struct kstatfs *buf)
50{
51 int retval;
52
53 if (!dentry->d_sb->s_op->statfs)
54 return -ENOSYS;
55
56 memset(buf, 0, sizeof(*buf));
57 retval = security_sb_statfs(dentry);
58 if (retval)
59 return retval;
60 retval = dentry->d_sb->s_op->statfs(dentry, buf);
61 if (retval == 0 && buf->f_frsize == 0)
62 buf->f_frsize = buf->f_bsize;
63 return retval;
64}
65
66int vfs_statfs(struct path *path, struct kstatfs *buf)
67{
68 int error;
69
70 error = statfs_by_dentry(path->dentry, buf);
71 if (!error)
72 buf->f_flags = calculate_f_flags(path->mnt);
73 return error;
74}
75EXPORT_SYMBOL(vfs_statfs);
76
77int user_statfs(const char __user *pathname, struct kstatfs *st)
78{
79 struct path path;
80 int error;
81 unsigned int lookup_flags = LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT;
82retry:
83 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
84 if (!error) {
85 error = vfs_statfs(&path, st);
86 path_put(&path);
87 if (retry_estale(error, lookup_flags)) {
88 lookup_flags |= LOOKUP_REVAL;
89 goto retry;
90 }
91 }
92 return error;
93}
94
95int fd_statfs(int fd, struct kstatfs *st)
96{
97 struct fd f = fdget_raw(fd);
98 int error = -EBADF;
99 if (f.file) {
100 error = vfs_statfs(&f.file->f_path, st);
101 fdput(f);
102 }
103 return error;
104}
105
106static int do_statfs_native(struct kstatfs *st, struct statfs __user *p)
107{
108 struct statfs buf;
109
110 if (sizeof(buf) == sizeof(*st))
111 memcpy(&buf, st, sizeof(*st));
112 else {
113 if (sizeof buf.f_blocks == 4) {
114 if ((st->f_blocks | st->f_bfree | st->f_bavail |
115 st->f_bsize | st->f_frsize) &
116 0xffffffff00000000ULL)
117 return -EOVERFLOW;
118
119
120
121
122 if (st->f_files != -1 &&
123 (st->f_files & 0xffffffff00000000ULL))
124 return -EOVERFLOW;
125 if (st->f_ffree != -1 &&
126 (st->f_ffree & 0xffffffff00000000ULL))
127 return -EOVERFLOW;
128 }
129
130 buf.f_type = st->f_type;
131 buf.f_bsize = st->f_bsize;
132 buf.f_blocks = st->f_blocks;
133 buf.f_bfree = st->f_bfree;
134 buf.f_bavail = st->f_bavail;
135 buf.f_files = st->f_files;
136 buf.f_ffree = st->f_ffree;
137 buf.f_fsid = st->f_fsid;
138 buf.f_namelen = st->f_namelen;
139 buf.f_frsize = st->f_frsize;
140 buf.f_flags = st->f_flags;
141 memset(buf.f_spare, 0, sizeof(buf.f_spare));
142 }
143 if (copy_to_user(p, &buf, sizeof(buf)))
144 return -EFAULT;
145 return 0;
146}
147
148static int do_statfs64(struct kstatfs *st, struct statfs64 __user *p)
149{
150 struct statfs64 buf;
151 if (sizeof(buf) == sizeof(*st))
152 memcpy(&buf, st, sizeof(*st));
153 else {
154 buf.f_type = st->f_type;
155 buf.f_bsize = st->f_bsize;
156 buf.f_blocks = st->f_blocks;
157 buf.f_bfree = st->f_bfree;
158 buf.f_bavail = st->f_bavail;
159 buf.f_files = st->f_files;
160 buf.f_ffree = st->f_ffree;
161 buf.f_fsid = st->f_fsid;
162 buf.f_namelen = st->f_namelen;
163 buf.f_frsize = st->f_frsize;
164 buf.f_flags = st->f_flags;
165 memset(buf.f_spare, 0, sizeof(buf.f_spare));
166 }
167 if (copy_to_user(p, &buf, sizeof(buf)))
168 return -EFAULT;
169 return 0;
170}
171
172SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct statfs __user *, buf)
173{
174 struct kstatfs st;
175 int error = user_statfs(pathname, &st);
176 if (!error)
177 error = do_statfs_native(&st, buf);
178 return error;
179}
180
181SYSCALL_DEFINE3(statfs64, const char __user *, pathname, size_t, sz, struct statfs64 __user *, buf)
182{
183 struct kstatfs st;
184 int error;
185 if (sz != sizeof(*buf))
186 return -EINVAL;
187 error = user_statfs(pathname, &st);
188 if (!error)
189 error = do_statfs64(&st, buf);
190 return error;
191}
192
193SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf)
194{
195 struct kstatfs st;
196 int error = fd_statfs(fd, &st);
197 if (!error)
198 error = do_statfs_native(&st, buf);
199 return error;
200}
201
202SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user *, buf)
203{
204 struct kstatfs st;
205 int error;
206
207 if (sz != sizeof(*buf))
208 return -EINVAL;
209
210 error = fd_statfs(fd, &st);
211 if (!error)
212 error = do_statfs64(&st, buf);
213 return error;
214}
215
216int vfs_ustat(dev_t dev, struct kstatfs *sbuf)
217{
218 struct super_block *s = user_get_super(dev);
219 int err;
220 if (!s)
221 return -EINVAL;
222
223 err = statfs_by_dentry(s->s_root, sbuf);
224 drop_super(s);
225 return err;
226}
227
228SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
229{
230 struct ustat tmp;
231 struct kstatfs sbuf;
232 int err = vfs_ustat(new_decode_dev(dev), &sbuf);
233 if (err)
234 return err;
235
236 memset(&tmp,0,sizeof(struct ustat));
237 tmp.f_tfree = sbuf.f_bfree;
238 tmp.f_tinode = sbuf.f_ffree;
239
240 return copy_to_user(ubuf, &tmp, sizeof(struct ustat)) ? -EFAULT : 0;
241}
242
