Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Wrapper functions for accessing the file_struct fd array.
4 */
5
6#ifndef __LINUX_FILE_H
7#define __LINUX_FILE_H
8
9#include <linux/compiler.h>
10#include <linux/types.h>
11#include <linux/posix_types.h>
12#include <linux/errno.h>
13#include <linux/cleanup.h>
14#include <linux/err.h>
15
16struct file;
17
18extern void fput(struct file *);
19
20struct file_operations;
21struct task_struct;
22struct vfsmount;
23struct dentry;
24struct inode;
25struct path;
26extern struct file *alloc_file_pseudo(struct inode *, struct vfsmount *,
27 const char *, int flags, const struct file_operations *);
28extern struct file *alloc_file_pseudo_noaccount(struct inode *, struct vfsmount *,
29 const char *, int flags, const struct file_operations *);
30extern struct file *alloc_file_clone(struct file *, int flags,
31 const struct file_operations *);
32
33static inline void fput_light(struct file *file, int fput_needed)
34{
35 if (fput_needed)
36 fput(file);
37}
38
39/* either a reference to struct file + flags
40 * (cloned vs. borrowed, pos locked), with
41 * flags stored in lower bits of value,
42 * or empty (represented by 0).
43 */
44struct fd {
45 unsigned long word;
46};
47#define FDPUT_FPUT 1
48#define FDPUT_POS_UNLOCK 2
49
50#define fd_file(f) ((struct file *)((f).word & ~(FDPUT_FPUT|FDPUT_POS_UNLOCK)))
51static inline bool fd_empty(struct fd f)
52{
53 return unlikely(!f.word);
54}
55
56#define EMPTY_FD (struct fd){0}
57static inline struct fd BORROWED_FD(struct file *f)
58{
59 return (struct fd){(unsigned long)f};
60}
61static inline struct fd CLONED_FD(struct file *f)
62{
63 return (struct fd){(unsigned long)f | FDPUT_FPUT};
64}
65
66static inline void fdput(struct fd fd)
67{
68 if (fd.word & FDPUT_FPUT)
69 fput(fd_file(fd));
70}
71
72extern struct file *fget(unsigned int fd);
73extern struct file *fget_raw(unsigned int fd);
74extern struct file *fget_task(struct task_struct *task, unsigned int fd);
75extern void __f_unlock_pos(struct file *);
76
77struct fd fdget(unsigned int fd);
78struct fd fdget_raw(unsigned int fd);
79struct fd fdget_pos(unsigned int fd);
80
81static inline void fdput_pos(struct fd f)
82{
83 if (f.word & FDPUT_POS_UNLOCK)
84 __f_unlock_pos(fd_file(f));
85 fdput(f);
86}
87
88DEFINE_CLASS(fd, struct fd, fdput(_T), fdget(fd), int fd)
89DEFINE_CLASS(fd_raw, struct fd, fdput(_T), fdget_raw(fd), int fd)
90
91extern int f_dupfd(unsigned int from, struct file *file, unsigned flags);
92extern int replace_fd(unsigned fd, struct file *file, unsigned flags);
93extern void set_close_on_exec(unsigned int fd, int flag);
94extern bool get_close_on_exec(unsigned int fd);
95extern int __get_unused_fd_flags(unsigned flags, unsigned long nofile);
96extern int get_unused_fd_flags(unsigned flags);
97extern void put_unused_fd(unsigned int fd);
98
99DEFINE_CLASS(get_unused_fd, int, if (_T >= 0) put_unused_fd(_T),
100 get_unused_fd_flags(flags), unsigned flags)
101DEFINE_FREE(fput, struct file *, if (!IS_ERR_OR_NULL(_T)) fput(_T))
102
103/*
104 * take_fd() will take care to set @fd to -EBADF ensuring that
105 * CLASS(get_unused_fd) won't call put_unused_fd(). This makes it
106 * easier to rely on CLASS(get_unused_fd):
107 *
108 * struct file *f;
109 *
110 * CLASS(get_unused_fd, fd)(O_CLOEXEC);
111 * if (fd < 0)
112 * return fd;
113 *
114 * f = dentry_open(&path, O_RDONLY, current_cred());
115 * if (IS_ERR(f))
116 * return PTR_ERR(f);
117 *
118 * fd_install(fd, f);
119 * return take_fd(fd);
120 */
121#define take_fd(fd) __get_and_null(fd, -EBADF)
122
123extern void fd_install(unsigned int fd, struct file *file);
124
125int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags);
126
127int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags);
128
129extern void flush_delayed_fput(void);
130extern void __fput_sync(struct file *);
131
132extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max;
133
134#endif /* __LINUX_FILE_H */