/* * Wrapper functions for accessing the file_struct fd array. */ #ifndef __LINUX_FILE_H #define __LINUX_FILE_H #include <asm/atomic.h> #include <linux/posix_types.h> #include <linux/compiler.h> #include <linux/spinlock.h> #include <linux/rcupdate.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 struct fdtable { unsigned int max_fds; int max_fdset; int next_fd; struct file ** fd; /* current fd array */ fd_set *close_on_exec; fd_set *open_fds; struct rcu_head rcu; struct files_struct *free_files; struct fdtable *next; }; /* * Open file table structure */ struct files_struct { atomic_t count; struct fdtable *fdt; struct fdtable fdtab; fd_set close_on_exec_init; fd_set open_fds_init; struct file * fd_array[NR_OPEN_DEFAULT]; spinlock_t file_lock; /* Protects concurrent writers. Nests inside tsk->alloc_lock */ }; #define files_fdtable(files) (rcu_dereference((files)->fdt)) extern void FASTCALL(__fput(struct file *)); extern void FASTCALL(fput(struct file *)); static inline void fput_light(struct file *file, int fput_needed) { if (unlikely(fput_needed)) fput(file); } extern struct file * FASTCALL(fget(unsigned int fd)); extern struct file * FASTCALL(fget_light(unsigned int fd, int *fput_needed)); extern void FASTCALL(set_close_on_exec(unsigned int fd, int flag)); extern void put_filp(struct file *); extern int get_unused_fd(void); extern void FASTCALL(put_unused_fd(unsigned int fd)); struct kmem_cache; extern void filp_ctor(void * objp, struct kmem_cache *cachep, unsigned long cflags); extern void filp_dtor(void * objp, struct kmem_cache *cachep, unsigned long dflags); extern struct file ** alloc_fd_array(int); extern void free_fd_array(struct file **, int); extern fd_set *alloc_fdset(int); extern void free_fdset(fd_set *, int); extern int expand_files(struct files_struct *, int nr); extern void free_fdtable(struct fdtable *fdt); extern void __init files_defer_init(void); 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) extern void FASTCALL(fd_install(unsigned int fd, struct file * file)); struct task_struct; struct files_struct *get_files_struct(struct task_struct *); void FASTCALL(put_files_struct(struct files_struct *fs)); #endif /* __LINUX_FILE_H */