/* * Wrapper functions for accessing the file_struct fd array. */#ifndef __LINUX_FILE_H#define __LINUX_FILE_Hextern void FASTCALL(fput(struct file *));extern struct file * FASTCALL(fget(unsigned int fd)); static inline int get_close_on_exec(unsigned int fd){	struct files_struct *files = current->files;	int res;	read_lock(&files->file_lock);	res = FD_ISSET(fd, files->close_on_exec);	read_unlock(&files->file_lock);	return res;}static inline void set_close_on_exec(unsigned int fd, int flag){	struct files_struct *files = current->files;	write_lock(&files->file_lock);	if (flag)		FD_SET(fd, files->close_on_exec);	else		FD_CLR(fd, files->close_on_exec);	write_unlock(&files->file_lock);}static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd){	struct file * file = NULL;	if (fd < files->max_fds)		file = files->fd[fd];	return file;}/* * Check whether the specified fd has an open file. */static inline struct file * fcheck(unsigned int fd){	struct file * file = NULL;	struct files_struct *files = current->files;	if (fd < files->max_fds)		file = files->fd[fd];	return file;}extern void put_filp(struct file *);extern int get_unused_fd(void);static inline void __put_unused_fd(struct files_struct *files, unsigned int fd){	FD_CLR(fd, files->open_fds);	if (fd < files->next_fd)		files->next_fd = fd;}static inline void put_unused_fd(unsigned int fd){	struct files_struct *files = current->files;	write_lock(&files->file_lock);	__put_unused_fd(files, fd);	write_unlock(&files->file_lock);}/* * Install a file pointer in the fd array.   * * The VFS is full of places where we drop the files lock between * setting the open_fds bitmap and installing the file in the file * array.  At any such point, we are vulnerable to a dup2() race * installing a file in the array before us.  We need to detect this and * fput() the struct file we are about to overwrite in this case. * * It should never happen - if we allow dup2() do it, _really_ bad things * will follow. */static inline void fd_install(unsigned int fd, struct file * file){	struct files_struct *files = current->files;		write_lock(&files->file_lock);	if (files->fd[fd])		BUG();	files->fd[fd] = file;	write_unlock(&files->file_lock);}void put_files_struct(struct files_struct *fs);#endif /* __LINUX_FILE_H */