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 16 struct file; 17 18 extern void fput(struct file *); 19 20 struct file_operations; 21 struct task_struct; 22 struct vfsmount; 23 struct dentry; 24 struct inode; 25 struct path; 26 extern struct file *alloc_file_pseudo(struct inode *, struct vfsmount *, 27 const char *, int flags, const struct file_operations *); 28 extern struct file *alloc_file_pseudo_noaccount(struct inode *, struct vfsmount *, 29 const char *, int flags, const struct file_operations *); 30 extern struct file *alloc_file_clone(struct file *, int flags, 31 const struct file_operations *); 32 33 static inline void fput_light(struct file *file, int fput_needed) 34 { 35 if (fput_needed) 36 fput(file); 37 } 38 39 struct fd { 40 struct file *file; 41 unsigned int flags; 42 }; 43 #define FDPUT_FPUT 1 44 #define FDPUT_POS_UNLOCK 2 45 46 static inline void fdput(struct fd fd) 47 { 48 if (fd.flags & FDPUT_FPUT) 49 fput(fd.file); 50 } 51 52 extern struct file *fget(unsigned int fd); 53 extern struct file *fget_raw(unsigned int fd); 54 extern struct file *fget_task(struct task_struct *task, unsigned int fd); 55 extern unsigned long __fdget(unsigned int fd); 56 extern unsigned long __fdget_raw(unsigned int fd); 57 extern unsigned long __fdget_pos(unsigned int fd); 58 extern void __f_unlock_pos(struct file *); 59 60 static inline struct fd __to_fd(unsigned long v) 61 { 62 return (struct fd){(struct file *)(v & ~3),v & 3}; 63 } 64 65 static inline struct fd fdget(unsigned int fd) 66 { 67 return __to_fd(__fdget(fd)); 68 } 69 70 static inline struct fd fdget_raw(unsigned int fd) 71 { 72 return __to_fd(__fdget_raw(fd)); 73 } 74 75 static inline struct fd fdget_pos(int fd) 76 { 77 return __to_fd(__fdget_pos(fd)); 78 } 79 80 static inline void fdput_pos(struct fd f) 81 { 82 if (f.flags & FDPUT_POS_UNLOCK) 83 __f_unlock_pos(f.file); 84 fdput(f); 85 } 86 87 DEFINE_CLASS(fd, struct fd, fdput(_T), fdget(fd), int fd) 88 DEFINE_CLASS(fd_raw, struct fd, fdput(_T), fdget_raw(fd), int fd) 89 90 extern int f_dupfd(unsigned int from, struct file *file, unsigned flags); 91 extern int replace_fd(unsigned fd, struct file *file, unsigned flags); 92 extern void set_close_on_exec(unsigned int fd, int flag); 93 extern bool get_close_on_exec(unsigned int fd); 94 extern int __get_unused_fd_flags(unsigned flags, unsigned long nofile); 95 extern int get_unused_fd_flags(unsigned flags); 96 extern void put_unused_fd(unsigned int fd); 97 98 DEFINE_CLASS(get_unused_fd, int, if (_T >= 0) put_unused_fd(_T), 99 get_unused_fd_flags(flags), unsigned flags) 100 DEFINE_FREE(fput, struct file *, if (!IS_ERR_OR_NULL(_T)) fput(_T)) 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(f); 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