LXR linux-bk/include/linux/file.h

   1/*
   2 * Wrapper functions for accessing the file_struct fd array.
   3 */
   4
   5#ifndef __LINUX_FILE_H
   6#define __LINUX_FILE_H
   7
   8#include <asm/atomic.h>
   9#include <linux/posix_types.h>
  10#include <linux/compiler.h>
  11#include <linux/spinlock.h>
  12
  13/*
  14 * The default fd array needs to be at least BITS_PER_LONG,
  15 * as this is the granularity returned by copy_fdset().
  16 */
  17#define NR_OPEN_DEFAULT BITS_PER_LONG
  18
  19/*
  20 * Open file table structure
  21 */
  22struct files_struct {
  23        atomic_t count;
  24        rwlock_t file_lock;     /* Protects all the below members.  Nests inside tsk->alloc_lock */
  25        int max_fds;
  26        int max_fdset;
  27        int next_fd;
  28        struct file ** fd;      /* current fd array */
  29        fd_set *close_on_exec;
  30        fd_set *open_fds;
  31        fd_set close_on_exec_init;
  32        fd_set open_fds_init;
  33        struct file * fd_array[NR_OPEN_DEFAULT];
  34};
  35
  36extern void FASTCALL(__fput(struct file *));
  37extern void FASTCALL(fput(struct file *));
  38extern struct file * FASTCALL(fget(unsigned int fd));
  39extern void FASTCALL(set_close_on_exec(unsigned int fd, int flag));
  40extern void put_filp(struct file *);
  41extern int get_unused_fd(void);
  42extern void FASTCALL(put_unused_fd(unsigned int fd));
  43
  44
  45static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd)
  46{
  47        struct file * file = NULL;
  48
  49        if (fd < files->max_fds)
  50                file = files->fd[fd];
  51        return file;
  52}
  53
  54/*
  55 * Check whether the specified fd has an open file.
  56 */
  57#define fcheck(fd)      fcheck_files(current->files, fd)
  58
  59extern void FASTCALL(fd_install(unsigned int fd, struct file * file));
  60void FASTCALL(put_files_struct(struct files_struct *fs));
  61
  62#endif /* __LINUX_FILE_H */
  63