| 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 void __f_unlock_pos(struct file *); |
| 76 | |
| 77 | struct fd fdget(unsigned int fd); |
| 78 | struct fd fdget_raw(unsigned int fd); |
| 79 | struct fd fdget_pos(unsigned int fd); |
| 80 | |
| 81 | static inline void fdput_pos(struct fd f) |
| 82 | { |
| 83 | if (f.word & 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 | DEFINE_FREE(fput, struct file *, if (!IS_ERR_OR_NULL(_T)) fput(_T)) |
| 102 | |
| 103 | /* |
| 104 | * take_fd() will take care to set @fd to -EBADF ensuring that |
| 105 | * CLASS(get_unused_fd) won't call put_unused_fd(). This makes it |
| 106 | * easier to rely on CLASS(get_unused_fd): |
| 107 | * |
| 108 | * struct file *f; |
| 109 | * |
| 110 | * CLASS(get_unused_fd, fd)(O_CLOEXEC); |
| 111 | * if (fd < 0) |
| 112 | * return fd; |
| 113 | * |
| 114 | * f = dentry_open(&path, O_RDONLY, current_cred()); |
| 115 | * if (IS_ERR(f)) |
| 116 | * return PTR_ERR(f); |
| 117 | * |
| 118 | * fd_install(fd, f); |
| 119 | * return take_fd(fd); |
| 120 | */ |
| 121 | #define take_fd(fd) __get_and_null(fd, -EBADF) |
| 122 | |
| 123 | extern void fd_install(unsigned int fd, struct file *file); |
| 124 | |
| 125 | int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags); |
| 126 | |
| 127 | int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags); |
| 128 | |
| 129 | extern void flush_delayed_fput(void); |
| 130 | extern void __fput_sync(struct file *); |
| 131 | |
| 132 | extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max; |
| 133 | |
| 134 | #endif /* __LINUX_FILE_H */ |