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 /* 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 */ 44 struct 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))) 51 static inline bool fd_empty(struct fd f) 52 { 53 return unlikely(!f.word); 54 } 55 56 #define EMPTY_FD (struct fd){0} 57 static inline struct fd BORROWED_FD(struct file *f) 58 { 59 return (struct fd){(unsigned long)f}; 60 } 61 static inline struct fd CLONED_FD(struct file *f) 62 { 63 return (struct fd){(unsigned long)f | FDPUT_FPUT}; 64 } 65 66 static inline void fdput(struct fd fd) 67 { 68 if (fd.word & FDPUT_FPUT) 69 fput(fd_file(fd)); 70 } 71 72 extern struct file *fget(unsigned int fd); 73 extern struct file *fget_raw(unsigned int fd); 74 extern struct file *fget_task(struct task_struct *task, unsigned int fd); 75 extern struct file *fget_task_next(struct task_struct *task, unsigned int *fd); 76 extern void __f_unlock_pos(struct file *); 77 78 struct fd fdget(unsigned int fd); 79 struct fd fdget_raw(unsigned int fd); 80 struct fd fdget_pos(unsigned int fd); 81 82 static inline void fdput_pos(struct fd f) 83 { 84 if (f.word & FDPUT_POS_UNLOCK) 85 __f_unlock_pos(fd_file(f)); 86 fdput(f); 87 } 88 89 DEFINE_CLASS(fd, struct fd, fdput(_T), fdget(fd), int fd) 90 DEFINE_CLASS(fd_raw, struct fd, fdput(_T), fdget_raw(fd), int fd) 91 92 extern int f_dupfd(unsigned int from, struct file *file, unsigned flags); 93 extern int replace_fd(unsigned fd, struct file *file, unsigned flags); 94 extern void set_close_on_exec(unsigned int fd, int flag); 95 extern bool get_close_on_exec(unsigned int fd); 96 extern int __get_unused_fd_flags(unsigned flags, unsigned long nofile); 97 extern int get_unused_fd_flags(unsigned flags); 98 extern void put_unused_fd(unsigned int fd); 99 100 DEFINE_CLASS(get_unused_fd, int, if (_T >= 0) put_unused_fd(_T), 101 get_unused_fd_flags(flags), unsigned flags) 102 DEFINE_FREE(fput, struct file *, if (!IS_ERR_OR_NULL(_T)) fput(_T)) 103 104 /* 105 * take_fd() will take care to set @fd to -EBADF ensuring that 106 * CLASS(get_unused_fd) won't call put_unused_fd(). This makes it 107 * easier to rely on CLASS(get_unused_fd): 108 * 109 * struct file *f; 110 * 111 * CLASS(get_unused_fd, fd)(O_CLOEXEC); 112 * if (fd < 0) 113 * return fd; 114 * 115 * f = dentry_open(&path, O_RDONLY, current_cred()); 116 * if (IS_ERR(f)) 117 * return PTR_ERR(f); 118 * 119 * fd_install(fd, f); 120 * return take_fd(fd); 121 */ 122 #define take_fd(fd) __get_and_null(fd, -EBADF) 123 124 extern void fd_install(unsigned int fd, struct file *file); 125 126 int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags); 127 128 int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags); 129 130 extern void flush_delayed_fput(void); 131 extern void __fput_sync(struct file *); 132 133 extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max; 134 135 #endif /* __LINUX_FILE_H */ 136