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
15 struct file;
16
17 extern void fput(struct file *);
18
19 struct file_operations;
20 struct task_struct;
21 struct vfsmount;
22 struct dentry;
23 struct inode;
24 struct path;
25 extern struct file *alloc_file_pseudo(struct inode *, struct vfsmount *,
26 const char *, int flags, const struct file_operations *);
27 extern struct file *alloc_file_pseudo_noaccount(struct inode *, struct vfsmount *,
28 const char *, int flags, const struct file_operations *);
29 extern struct file *alloc_file_clone(struct file *, int flags,
30 const struct file_operations *);
31
32 static inline void fput_light(struct file *file, int fput_needed)
33 {
34 if (fput_needed)
35 fput(file);
36 }
37
38 struct fd {
39 struct file *file;
40 unsigned int flags;
41 };
42 #define FDPUT_FPUT 1
43 #define FDPUT_POS_UNLOCK 2
44
45 static inline void fdput(struct fd fd)
46 {
47 if (fd.flags & FDPUT_FPUT)
48 fput(fd.file);
49 }
50
51 extern struct file *fget(unsigned int fd);
52 extern struct file *fget_raw(unsigned int fd);
53 extern struct file *fget_task(struct task_struct *task, unsigned int fd);
54 extern unsigned long __fdget(unsigned int fd);
55 extern unsigned long __fdget_raw(unsigned int fd);
56 extern unsigned long __fdget_pos(unsigned int fd);
57 extern void __f_unlock_pos(struct file *);
58
59 static inline struct fd __to_fd(unsigned long v)
60 {
61 return (struct fd){(struct file *)(v & ~3),v & 3};
62 }
63
64 static inline struct fd fdget(unsigned int fd)
65 {
66 return __to_fd(__fdget(fd));
67 }
68
69 static inline struct fd fdget_raw(unsigned int fd)
70 {
71 return __to_fd(__fdget_raw(fd));
72 }
73
74 static inline struct fd fdget_pos(int fd)
75 {
76 return __to_fd(__fdget_pos(fd));
77 }
78
79 static inline void fdput_pos(struct fd f)
80 {
81 if (f.flags & FDPUT_POS_UNLOCK)
82 __f_unlock_pos(f.file);
83 fdput(f);
84 }
85
86 DEFINE_CLASS(fd, struct fd, fdput(_T), fdget(fd), int fd)
87 DEFINE_CLASS(fd_raw, struct fd, fdput(_T), fdget_raw(fd), int fd)
88
89 extern int f_dupfd(unsigned int from, struct file *file, unsigned flags);
90 extern int replace_fd(unsigned fd, struct file *file, unsigned flags);
91 extern void set_close_on_exec(unsigned int fd, int flag);
92 extern bool get_close_on_exec(unsigned int fd);
93 extern int __get_unused_fd_flags(unsigned flags, unsigned long nofile);
94 extern int get_unused_fd_flags(unsigned flags);
95 extern void put_unused_fd(unsigned int fd);
96
97 DEFINE_CLASS(get_unused_fd, int, if (_T >= 0) put_unused_fd(_T),
98 get_unused_fd_flags(flags), unsigned flags)
99
100 /*
101 * take_fd() will take care to set @fd to -EBADF ensuring that
102 * CLASS(get_unused_fd) won't call put_unused_fd(). This makes it
103 * easier to rely on CLASS(get_unused_fd):
104 *
105 * struct file *f;
106 *
107 * CLASS(get_unused_fd, fd)(O_CLOEXEC);
108 * if (fd < 0)
109 * return fd;
110 *
111 * f = dentry_open(&path, O_RDONLY, current_cred());
112 * if (IS_ERR(f))
113 * return PTR_ERR(f);
114 *
115 * fd_install(fd, f);
116 * return take_fd(fd);
117 */
118 #define take_fd(fd) __get_and_null(fd, -EBADF)
119
120 extern void fd_install(unsigned int fd, struct file *file);
121
122 int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags);
123
124 int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags);
125
126 extern void flush_delayed_fput(void);
127 extern void __fput_sync(struct file *);
128
129 extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max;
130
131 #endif /* __LINUX_FILE_H */
132
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