1 /* SPDX-License-Identifier: GPL-2.0 */
3 * descriptor table internals; you almost certainly want file.h instead.
6 #ifndef __LINUX_FDTABLE_H
7 #define __LINUX_FDTABLE_H
9 #include <linux/posix_types.h>
10 #include <linux/compiler.h>
11 #include <linux/spinlock.h>
12 #include <linux/rcupdate.h>
13 #include <linux/types.h>
14 #include <linux/init.h>
17 #include <linux/atomic.h>
20 * The default fd array needs to be at least BITS_PER_LONG,
21 * as this is the granularity returned by copy_fdset().
23 #define NR_OPEN_DEFAULT BITS_PER_LONG
27 struct file __rcu
**fd
; /* current fd array */
28 unsigned long *close_on_exec
;
29 unsigned long *open_fds
;
30 unsigned long *full_fds_bits
;
34 static inline bool close_on_exec(unsigned int fd
, const struct fdtable
*fdt
)
36 return test_bit(fd
, fdt
->close_on_exec
);
39 static inline bool fd_is_open(unsigned int fd
, const struct fdtable
*fdt
)
41 return test_bit(fd
, fdt
->open_fds
);
45 * Open file table structure
52 bool resize_in_progress
;
53 wait_queue_head_t resize_wait
;
55 struct fdtable __rcu
*fdt
;
58 * written part on a separate cache line in SMP
60 spinlock_t file_lock ____cacheline_aligned_in_smp
;
62 unsigned long close_on_exec_init
[1];
63 unsigned long open_fds_init
[1];
64 unsigned long full_fds_bits_init
[1];
65 struct file __rcu
* fd_array
[NR_OPEN_DEFAULT
];
68 struct file_operations
;
72 #define rcu_dereference_check_fdtable(files, fdtfd) \
73 rcu_dereference_check((fdtfd), lockdep_is_held(&(files)->file_lock))
75 #define files_fdtable(files) \
76 rcu_dereference_check_fdtable((files), (files)->fdt)
79 * The caller must ensure that fd table isn't shared or hold rcu or file lock
81 static inline struct file
*__fcheck_files(struct files_struct
*files
, unsigned int fd
)
83 struct fdtable
*fdt
= rcu_dereference_raw(files
->fdt
);
85 if (fd
< fdt
->max_fds
)
86 return rcu_dereference_raw(fdt
->fd
[fd
]);
90 static inline struct file
*fcheck_files(struct files_struct
*files
, unsigned int fd
)
92 RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&
93 !lockdep_is_held(&files
->file_lock
),
94 "suspicious rcu_dereference_check() usage");
95 return __fcheck_files(files
, fd
);
99 * Check whether the specified fd has an open file.
101 #define fcheck(fd) fcheck_files(current->files, fd)
105 struct files_struct
*get_files_struct(struct task_struct
*);
106 void put_files_struct(struct files_struct
*fs
);
107 void reset_files_struct(struct files_struct
*);
108 int unshare_files(struct files_struct
**);
109 struct files_struct
*dup_fd(struct files_struct
*, int *) __latent_entropy
;
110 void do_close_on_exec(struct files_struct
*);
111 int iterate_fd(struct files_struct
*, unsigned,
112 int (*)(const void *, struct file
*, unsigned),
115 extern int __alloc_fd(struct files_struct
*files
,
116 unsigned start
, unsigned end
, unsigned flags
);
117 extern void __fd_install(struct files_struct
*files
,
118 unsigned int fd
, struct file
*file
);
119 extern int __close_fd(struct files_struct
*files
,
122 extern struct kmem_cache
*files_cachep
;
124 #endif /* __LINUX_FDTABLE_H */