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 12 static 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 33 static 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 43 static 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 49 static 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 66 int 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 } 75 EXPORT_SYMBOL(vfs_statfs); 76 77 int 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; 82 retry: 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 95 int 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 } 105 106 static 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 * f_files and f_ffree may be -1; it's okay to stuff 120 * that into 32 bits 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 } 147 148 static 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 } 171 172 SYSCALL_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 } 180 181 SYSCALL_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 } 192 193 SYSCALL_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 } 201 202 SYSCALL_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 } 215 216 int 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 } 227 228 SYSCALL_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