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
33/* either a reference to struct file + flags
34 * (cloned vs. borrowed, pos locked), with
35 * flags stored in lower bits of value,
36 * or empty (represented by 0).
37 */
38struct fd {
39 unsigned long word;
40};
41#define FDPUT_FPUT 1
42#define FDPUT_POS_UNLOCK 2
43
44#define fd_file(f) ((struct file *)((f).word & ~(FDPUT_FPUT|FDPUT_POS_UNLOCK)))
45static inline bool fd_empty(struct fd f)
46{
47 return unlikely(!f.word);
48}
49
50#define EMPTY_FD (struct fd){0}
51static inline struct fd BORROWED_FD(struct file *f)
52{
53 return (struct fd){(unsigned long)f};
54}
55static inline struct fd CLONED_FD(struct file *f)
56{
57 return (struct fd){(unsigned long)f | FDPUT_FPUT};
58}
59
60static inline void fdput(struct fd fd)
61{
62 if (unlikely(fd.word & FDPUT_FPUT))
63 fput(fd_file(fd));
64}
65
66extern struct file *fget(unsigned int fd);
67extern struct file *fget_raw(unsigned int fd);
68extern struct file *fget_task(struct task_struct *task, unsigned int fd);
69extern struct file *fget_task_next(struct task_struct *task, unsigned int *fd);
70extern void __f_unlock_pos(struct file *);
71
72struct fd fdget(unsigned int fd);
73struct fd fdget_raw(unsigned int fd);
74struct fd fdget_pos(unsigned int fd);
75
76static inline void fdput_pos(struct fd f)
77{
78 if (f.word & FDPUT_POS_UNLOCK)
79 __f_unlock_pos(fd_file(f));
80 fdput(fd: f);
81}
82
83DEFINE_CLASS(fd, struct fd, fdput(_T), fdget(fd), int fd)
84DEFINE_CLASS(fd_raw, struct fd, fdput(_T), fdget_raw(fd), int fd)
85DEFINE_CLASS(fd_pos, struct fd, fdput_pos(_T), fdget_pos(fd), int fd)
86
87extern int f_dupfd(unsigned int from, struct file *file, unsigned flags);
88extern int replace_fd(unsigned fd, struct file *file, unsigned flags);
89extern void set_close_on_exec(unsigned int fd, int flag);
90extern bool get_close_on_exec(unsigned int fd);
91extern int __get_unused_fd_flags(unsigned flags, unsigned long nofile);
92extern int get_unused_fd_flags(unsigned flags);
93extern void put_unused_fd(unsigned int fd);
94
95DEFINE_CLASS(get_unused_fd, int, if (_T >= 0) put_unused_fd(_T),
96 get_unused_fd_flags(flags), unsigned flags)
97DEFINE_FREE(fput, struct file *, if (!IS_ERR_OR_NULL(_T)) fput(_T))
98
99/*
100 * take_fd() will take care to set @fd to -EBADF ensuring that
101 * CLASS(get_unused_fd) won't call put_unused_fd(). This makes it
102 * easier to rely on CLASS(get_unused_fd):
103 *
104 * struct file *f;
105 *
106 * CLASS(get_unused_fd, fd)(O_CLOEXEC);
107 * if (fd < 0)
108 * return fd;
109 *
110 * f = dentry_open(&path, O_RDONLY, current_cred());
111 * if (IS_ERR(f))
112 * return PTR_ERR(f);
113 *
114 * fd_install(fd, f);
115 * return take_fd(fd);
116 */
117#define take_fd(fd) __get_and_null(fd, -EBADF)
118
119extern void fd_install(unsigned int fd, struct file *file);
120
121int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags);
122
123int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags);
124
125extern void flush_delayed_fput(void);
126extern void __fput_sync(struct file *);
127
128extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max;
129
130#endif /* __LINUX_FILE_H */
131