initial_commit

1 files changed, 229 insertions, 0 deletions

diff --git a/fs/statfs.c b/fs/statfs.c
new file mode 100644
index 00000000..9cf04a11
--- /dev/null
+++ b/fs/statfs.c
@@ -0,0 +1,229 @@
+#include <linux/syscalls.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/statfs.h>
+#include <linux/security.h>
+#include <linux/uaccess.h>
+
+static int flags_by_mnt(int mnt_flags)
+{
+	int flags = 0;
+
+	if (mnt_flags & MNT_READONLY)
+		flags |= ST_RDONLY;
+	if (mnt_flags & MNT_NOSUID)
+		flags |= ST_NOSUID;
+	if (mnt_flags & MNT_NODEV)
+		flags |= ST_NODEV;
+	if (mnt_flags & MNT_NOEXEC)
+		flags |= ST_NOEXEC;
+	if (mnt_flags & MNT_NOATIME)
+		flags |= ST_NOATIME;
+	if (mnt_flags & MNT_NODIRATIME)
+		flags |= ST_NODIRATIME;
+	if (mnt_flags & MNT_RELATIME)
+		flags |= ST_RELATIME;
+	return flags;
+}
+
+static int flags_by_sb(int s_flags)
+{
+	int flags = 0;
+	if (s_flags & MS_SYNCHRONOUS)
+		flags |= ST_SYNCHRONOUS;
+	if (s_flags & MS_MANDLOCK)
+		flags |= ST_MANDLOCK;
+	return flags;
+}
+
+static int calculate_f_flags(struct vfsmount *mnt)
+{
+	return ST_VALID | flags_by_mnt(mnt->mnt_flags) |
+		flags_by_sb(mnt->mnt_sb->s_flags);
+}
+
+int statfs_by_dentry(struct dentry *dentry, struct kstatfs *buf)
+{
+	int retval;
+
+	if (!dentry->d_sb->s_op->statfs)
+		return -ENOSYS;
+
+	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;
+}
+
+int vfs_statfs(struct path *path, struct kstatfs *buf)
+{
+	int error;
+
+	error = statfs_by_dentry(path->dentry, buf);
+	if (!error)
+		buf->f_flags = calculate_f_flags(path->mnt);
+	return error;
+}
+EXPORT_SYMBOL(vfs_statfs);
+
+int user_statfs(const char __user *pathname, struct kstatfs *st)
+{
+	struct path path;
+	int error = user_path_at(AT_FDCWD, pathname, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path);
+	if (!error) {
+		error = vfs_statfs(&path, st);
+		path_put(&path);
+	}
+	return error;
+}
+
+int fd_statfs(int fd, struct kstatfs *st)
+{
+	struct file *file = fget(fd);
+	int error = -EBADF;
+	if (file) {
+		error = vfs_statfs(&file->f_path, st);
+		fput(file);
+	}
+	return error;
+}
+
+static int do_statfs_native(struct kstatfs *st, struct statfs __user *p)
+{
+	struct statfs buf;
+
+	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;
+		buf.f_flags = st->f_flags;
+		memset(buf.f_spare, 0, sizeof(buf.f_spare));
+	}
+	if (copy_to_user(p, &buf, sizeof(buf)))
+		return -EFAULT;
+	return 0;
+}
+
+static int do_statfs64(struct kstatfs *st, struct statfs64 __user *p)
+{
+	struct statfs64 buf;
+	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;
+		buf.f_flags = st->f_flags;
+		memset(buf.f_spare, 0, sizeof(buf.f_spare));
+	}
+	if (copy_to_user(p, &buf, sizeof(buf)))
+		return -EFAULT;
+	return 0;
+}
+
+SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct statfs __user *, buf)
+{
+	struct kstatfs st;
+	int error = user_statfs(pathname, &st);
+	if (!error)
+		error = do_statfs_native(&st, buf);
+	return error;
+}
+
+SYSCALL_DEFINE3(statfs64, const char __user *, pathname, size_t, sz, struct statfs64 __user *, buf)
+{
+	struct kstatfs st;
+	int error;
+	if (sz != sizeof(*buf))
+		return -EINVAL;
+	error = user_statfs(pathname, &st);
+	if (!error)
+		error = do_statfs64(&st, buf);
+	return error;
+}
+
+SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf)
+{
+	struct kstatfs st;
+	int error = fd_statfs(fd, &st);
+	if (!error)
+		error = do_statfs_native(&st, buf);
+	return error;
+}
+
+SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user *, buf)
+{
+	struct kstatfs st;
+	int error;
+
+	if (sz != sizeof(*buf))
+		return -EINVAL;
+
+	error = fd_statfs(fd, &st);
+	if (!error)
+		error = do_statfs64(&st, buf);
+	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 = statfs_by_dentry(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;
+}