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 */ 22 struct files_struct { 23 atomic_t count; 24 spinlock_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 36 extern void FASTCALL(__fput(struct file *)); 37 extern void FASTCALL(fput(struct file *)); 38 39 static inline void fput_light(struct file *file, int fput_needed) 40 { 41 if (unlikely(fput_needed)) 42 fput(file); 43 } 44 45 extern struct file * FASTCALL(fget(unsigned int fd)); 46 extern struct file * FASTCALL(fget_light(unsigned int fd, int *fput_needed)); 47 extern void FASTCALL(set_close_on_exec(unsigned int fd, int flag)); 48 extern void put_filp(struct file *); 49 extern int get_unused_fd(void); 50 extern void FASTCALL(put_unused_fd(unsigned int fd)); 51 struct kmem_cache_s; 52 extern void filp_ctor(void * objp, struct kmem_cache_s *cachep, unsigned long cflags); 53 extern void filp_dtor(void * objp, struct kmem_cache_s *cachep, unsigned long dflags); 54 55 extern struct file ** alloc_fd_array(int); 56 extern void free_fd_array(struct file **, int); 57 58 extern fd_set *alloc_fdset(int); 59 extern void free_fdset(fd_set *, int); 60 61 extern int expand_files(struct files_struct *, int nr); 62 63 static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd) 64 { 65 struct file * file = NULL; 66 67 if (fd < files->max_fds) 68 file = files->fd[fd]; 69 return file; 70 } 71 72 /* 73 * Check whether the specified fd has an open file. 74 */ 75 #define fcheck(fd) fcheck_files(current->files, fd) 76 77 extern void FASTCALL(fd_install(unsigned int fd, struct file * file)); 78 79 struct task_struct; 80 81 struct files_struct *get_files_struct(struct task_struct *); 82 void FASTCALL(put_files_struct(struct files_struct *fs)); 83 84 #endif /* __LINUX_FILE_H */ 85