/* * descriptor table internals; you almost certainly want file.h instead. */ #ifndef __LINUX_FDTABLE_H #define __LINUX_FDTABLE_H #include <asm/atomic.h> #include <linux/posix_types.h> #include <linux/compiler.h> #include <linux/spinlock.h> #include <linux/rcupdate.h> #include <linux/types.h> /* * The default fd array needs to be at least BITS_PER_LONG, * as this is the granularity returned by copy_fdset(). */ #define NR_OPEN_DEFAULT BITS_PER_LONG /* * The embedded_fd_set is a small fd_set, * suitable for most tasks (which open <= BITS_PER_LONG files) */ struct embedded_fd_set { unsigned long fds_bits[1]; }; struct fdtable { unsigned int max_fds; struct file ** fd; /* current fd array */ fd_set *close_on_exec; fd_set *open_fds; struct rcu_head rcu; struct fdtable *next; }; /* * Open file table structure */ struct files_struct { /* * read mostly part */ atomic_t count; struct fdtable *fdt; struct fdtable fdtab; /* * written part on a separate cache line in SMP */ spinlock_t file_lock ____cacheline_aligned_in_smp; int next_fd; struct embedded_fd_set close_on_exec_init; struct embedded_fd_set open_fds_init; struct file * fd_array[NR_OPEN_DEFAULT]; }; #define files_fdtable(files) (rcu_dereference((files)->fdt)) struct file_operations; struct vfsmount; struct dentry; extern int expand_files(struct files_struct *, int nr); extern void free_fdtable_rcu(struct rcu_head *rcu); extern void __init files_defer_init(void); static inline void free_fdtable(struct fdtable *fdt) { call_rcu(&fdt->rcu, free_fdtable_rcu); } static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd) { struct file * file = NULL; struct fdtable *fdt = files_fdtable(files); if (fd < fdt->max_fds) file = rcu_dereference(fdt->fd[fd]); return file; } /* * Check whether the specified fd has an open file. */ #define fcheck(fd) fcheck_files(current->files, fd) struct task_struct; struct files_struct *get_files_struct(struct task_struct *); void put_files_struct(struct files_struct *fs); void reset_files_struct(struct files_struct *); int unshare_files(struct files_struct **); struct files_struct *dup_fd(struct files_struct *, int *); extern struct kmem_cache *files_cachep; #endif /* __LINUX_FDTABLE_H */