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 /* either a reference to struct file + flags 39 * (cloned vs. borrowed, pos locked), with 40 * flags stored in lower bits of value, 41 * or empty (represented by 0). 42 */ 43 struct fd { 44 unsigned long word; 45 }; 46 #define FDPUT_FPUT 1 47 #define FDPUT_POS_UNLOCK 2 48 49 #define fd_file(f) ((struct file *)((f).word & ~(FDPUT_FPUT|FDPUT_POS_UNLOCK))) 50 static inline bool fd_empty(struct fd f) 51 { 52 return unlikely(!f.word); 53 } 54 55 #define EMPTY_FD (struct fd){0} 56 57 static inline void fdput(struct fd fd) 58 { 59 if (fd.word & FDPUT_FPUT) 60 fput(fd_file(fd)); 61 } 62 63 extern struct file *fget(unsigned int fd); 64 extern struct file *fget_raw(unsigned int fd); 65 extern struct file *fget_task(struct task_struct *task, unsigned int fd); 66 extern unsigned long __fdget(unsigned int fd); 67 extern unsigned long __fdget_raw(unsigned int fd); 68 extern unsigned long __fdget_pos(unsigned int fd); 69 extern void __f_unlock_pos(struct file *); 70 71 static inline struct fd __to_fd(unsigned long v) 72 { 73 return (struct fd){v}; 74 } 75 76 static inline struct fd fdget(unsigned int fd) 77 { 78 return __to_fd(__fdget(fd)); 79 } 80 81 static inline struct fd fdget_raw(unsigned int fd) 82 { 83 return __to_fd(__fdget_raw(fd)); 84 } 85 86 static inline struct fd fdget_pos(int fd) 87 { 88 return __to_fd(__fdget_pos(fd)); 89 } 90 91 static inline void fdput_pos(struct fd f) 92 { 93 if (f.word & FDPUT_POS_UNLOCK) 94 __f_unlock_pos(fd_file(f)); 95 fdput(f); 96 } 97 98 DEFINE_CLASS(fd, struct fd, fdput(_T), fdget(fd), int fd) 99 DEFINE_CLASS(fd_raw, struct fd, fdput(_T), fdget_raw(fd), int fd) 100 101 extern int f_dupfd(unsigned int from, struct file *file, unsigned flags); 102 extern int replace_fd(unsigned fd, struct file *file, unsigned flags); 103 extern void set_close_on_exec(unsigned int fd, int flag); 104 extern bool get_close_on_exec(unsigned int fd); 105 extern int __get_unused_fd_flags(unsigned flags, unsigned long nofile); 106 extern int get_unused_fd_flags(unsigned flags); 107 extern void put_unused_fd(unsigned int fd); 108 109 DEFINE_CLASS(get_unused_fd, int, if (_T >= 0) put_unused_fd(_T), 110 get_unused_fd_flags(flags), unsigned flags) 111 112 /* 113 * take_fd() will take care to set @fd to -EBADF ensuring that 114 * CLASS(get_unused_fd) won't call put_unused_fd(). This makes it 115 * easier to rely on CLASS(get_unused_fd): 116 * 117 * struct file *f; 118 * 119 * CLASS(get_unused_fd, fd)(O_CLOEXEC); 120 * if (fd < 0) 121 * return fd; 122 * 123 * f = dentry_open(&path, O_RDONLY, current_cred()); 124 * if (IS_ERR(f)) 125 * return PTR_ERR(fd); 126 * 127 * fd_install(fd, f); 128 * return take_fd(fd); 129 */ 130 #define take_fd(fd) __get_and_null(fd, -EBADF) 131 132 extern void fd_install(unsigned int fd, struct file *file); 133 134 int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags); 135 136 int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags); 137 138 extern void flush_delayed_fput(void); 139 extern void __fput_sync(struct file *); 140 141 extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max; 142 143 #endif /* __LINUX_FILE_H */ 144