2 * descriptor table internals; you almost certainly want file.h instead.
5 #ifndef __LINUX_FDTABLE_H
6 #define __LINUX_FDTABLE_H
8 #include <linux/posix_types.h>
9 #include <linux/compiler.h>
10 #include <linux/spinlock.h>
11 #include <linux/rcupdate.h>
12 #include <linux/types.h>
13 #include <linux/init.h>
16 #include <linux/atomic.h>
19 * The default fd array needs to be at least BITS_PER_LONG,
20 * as this is the granularity returned by copy_fdset().
22 #define NR_OPEN_DEFAULT BITS_PER_LONG
26 struct file __rcu **fd; /* current fd array */
27 unsigned long *close_on_exec;
28 unsigned long *open_fds;
32 static inline bool close_on_exec(int fd, const struct fdtable *fdt)
34 return test_bit(fd, fdt->close_on_exec);
37 static inline bool fd_is_open(int fd, const struct fdtable *fdt)
39 return test_bit(fd, fdt->open_fds);
43 * Open file table structure
50 struct fdtable __rcu *fdt;
53 * written part on a separate cache line in SMP
55 spinlock_t file_lock ____cacheline_aligned_in_smp;
57 unsigned long close_on_exec_init[1];
58 unsigned long open_fds_init[1];
59 struct file __rcu * fd_array[NR_OPEN_DEFAULT];
62 struct file_operations;
66 extern void __init files_defer_init(void);
68 #define rcu_dereference_check_fdtable(files, fdtfd) \
69 rcu_dereference_check((fdtfd), lockdep_is_held(&(files)->file_lock))
71 #define files_fdtable(files) \
72 rcu_dereference_check_fdtable((files), (files)->fdt)
75 * The caller must ensure that fd table isn't shared or hold rcu or file lock
77 static inline struct file *__fcheck_files(struct files_struct *files, unsigned int fd)
79 struct fdtable *fdt = rcu_dereference_raw(files->fdt);
81 if (fd < fdt->max_fds)
82 return rcu_dereference_raw(fdt->fd[fd]);
86 static inline struct file *fcheck_files(struct files_struct *files, unsigned int fd)
88 rcu_lockdep_assert(rcu_read_lock_held() ||
89 lockdep_is_held(&files->file_lock),
90 "suspicious rcu_dereference_check() usage");
91 return __fcheck_files(files, fd);
95 * Check whether the specified fd has an open file.
97 #define fcheck(fd) fcheck_files(current->files, fd)
101 struct files_struct *get_files_struct(struct task_struct *);
102 void put_files_struct(struct files_struct *fs);
103 void reset_files_struct(struct files_struct *);
104 int unshare_files(struct files_struct **);
105 struct files_struct *dup_fd(struct files_struct *, int *);
106 void do_close_on_exec(struct files_struct *);
107 int iterate_fd(struct files_struct *, unsigned,
108 int (*)(const void *, struct file *, unsigned),
111 extern int __alloc_fd(struct files_struct *files,
112 unsigned start, unsigned end, unsigned flags);
113 extern void __fd_install(struct files_struct *files,
114 unsigned int fd, struct file *file);
115 extern int __close_fd(struct files_struct *files,
118 extern struct kmem_cache *files_cachep;
120 #endif /* __LINUX_FDTABLE_H */