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 #define fd_file(f) ((f).file) 46 47 static inline void fdput(struct fd fd) 48 { 49 if (fd.flags & FDPUT_FPUT) 50 fput(fd_file(fd)); 51 } 52 53 extern struct file *fget(unsigned int fd); 54 extern struct file *fget_raw(unsigned int fd); 55 extern struct file *fget_task(struct task_struct *task, unsigned int fd); 56 extern unsigned long __fdget(unsigned int fd); 57 extern unsigned long __fdget_raw(unsigned int fd); 58 extern unsigned long __fdget_pos(unsigned int fd); 59 extern void __f_unlock_pos(struct file *); 60 61 static inline struct fd __to_fd(unsigned long v) 62 { 63 return (struct fd){(struct file *)(v & ~3),v & 3}; 64 } 65 66 static inline struct fd fdget(unsigned int fd) 67 { 68 return __to_fd(__fdget(fd)); 69 } 70 71 static inline struct fd fdget_raw(unsigned int fd) 72 { 73 return __to_fd(__fdget_raw(fd)); 74 } 75 76 static inline struct fd fdget_pos(int fd) 77 { 78 return __to_fd(__fdget_pos(fd)); 79 } 80 81 static inline void fdput_pos(struct fd f) 82 { 83 if (f.flags & FDPUT_POS_UNLOCK) 84 __f_unlock_pos(fd_file(f)); 85 fdput(f); 86 } 87 88 DEFINE_CLASS(fd, struct fd, fdput(_T), fdget(fd), int fd) 89 DEFINE_CLASS(fd_raw, struct fd, fdput(_T), fdget_raw(fd), int fd) 90 91 extern int f_dupfd(unsigned int from, struct file *file, unsigned flags); 92 extern int replace_fd(unsigned fd, struct file *file, unsigned flags); 93 extern void set_close_on_exec(unsigned int fd, int flag); 94 extern bool get_close_on_exec(unsigned int fd); 95 extern int __get_unused_fd_flags(unsigned flags, unsigned long nofile); 96 extern int get_unused_fd_flags(unsigned flags); 97 extern void put_unused_fd(unsigned int fd); 98 99 DEFINE_CLASS(get_unused_fd, int, if (_T >= 0) put_unused_fd(_T), 100 get_unused_fd_flags(flags), unsigned flags) 101 102 /* 103 * take_fd() will take care to set @fd to -EBADF ensuring that 104 * CLASS(get_unused_fd) won't call put_unused_fd(). This makes it 105 * easier to rely on CLASS(get_unused_fd): 106 * 107 * struct file *f; 108 * 109 * CLASS(get_unused_fd, fd)(O_CLOEXEC); 110 * if (fd < 0) 111 * return fd; 112 * 113 * f = dentry_open(&path, O_RDONLY, current_cred()); 114 * if (IS_ERR(f)) 115 * return PTR_ERR(fd); 116 * 117 * fd_install(fd, f); 118 * return take_fd(fd); 119 */ 120 #define take_fd(fd) __get_and_null(fd, -EBADF) 121 122 extern void fd_install(unsigned int fd, struct file *file); 123 124 int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags); 125 126 int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags); 127 128 extern void flush_delayed_fput(void); 129 extern void __fput_sync(struct file *); 130 131 extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max; 132 133 #endif /* __LINUX_FILE_H */ 134