#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); static int do_statfs_native(struct path *path, struct statfs *buf) { struct kstatfs st; int retval; retval = vfs_statfs(path, &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; buf->f_flags = st.f_flags; memset(buf->f_spare, 0, sizeof(buf->f_spare)); } return 0; } static int do_statfs64(struct path *path, struct statfs64 *buf) { struct kstatfs st; int retval; retval = vfs_statfs(path, &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; buf->f_flags = st.f_flags; 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 = do_statfs_native(&path, &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 = do_statfs64(&path, &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 = do_statfs_native(&file->f_path, &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 = do_statfs64(&file->f_path, &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 = 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; }