Commit | Line | Data |
---|---|---|
b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
9f3acc31 AV |
2 | /* |
3 | * descriptor table internals; you almost certainly want file.h instead. | |
4 | */ | |
5 | ||
6 | #ifndef __LINUX_FDTABLE_H | |
7 | #define __LINUX_FDTABLE_H | |
8 | ||
9f3acc31 AV |
9 | #include <linux/posix_types.h> |
10 | #include <linux/compiler.h> | |
11 | #include <linux/spinlock.h> | |
12 | #include <linux/rcupdate.h> | |
13 | #include <linux/types.h> | |
21e54459 | 14 | #include <linux/init.h> |
2c666df8 | 15 | #include <linux/fs.h> |
21e54459 | 16 | |
60063497 | 17 | #include <linux/atomic.h> |
9f3acc31 AV |
18 | |
19 | /* | |
20 | * The default fd array needs to be at least BITS_PER_LONG, | |
21 | * as this is the granularity returned by copy_fdset(). | |
22 | */ | |
23 | #define NR_OPEN_DEFAULT BITS_PER_LONG | |
24 | ||
9f3acc31 AV |
25 | struct fdtable { |
26 | unsigned int max_fds; | |
4d2deb40 | 27 | struct file __rcu **fd; /* current fd array */ |
1fd36adc DH |
28 | unsigned long *close_on_exec; |
29 | unsigned long *open_fds; | |
f3f86e33 | 30 | unsigned long *full_fds_bits; |
9f3acc31 | 31 | struct rcu_head rcu; |
9f3acc31 AV |
32 | }; |
33 | ||
9b80a184 | 34 | static inline bool close_on_exec(unsigned int fd, const struct fdtable *fdt) |
1dce27c5 | 35 | { |
1fd36adc | 36 | return test_bit(fd, fdt->close_on_exec); |
1dce27c5 DH |
37 | } |
38 | ||
9b80a184 | 39 | static inline bool fd_is_open(unsigned int fd, const struct fdtable *fdt) |
1dce27c5 | 40 | { |
1fd36adc | 41 | return test_bit(fd, fdt->open_fds); |
1dce27c5 DH |
42 | } |
43 | ||
9f3acc31 AV |
44 | /* |
45 | * Open file table structure | |
46 | */ | |
47 | struct files_struct { | |
48 | /* | |
49 | * read mostly part | |
50 | */ | |
51 | atomic_t count; | |
8a81252b ED |
52 | bool resize_in_progress; |
53 | wait_queue_head_t resize_wait; | |
54 | ||
4d2deb40 | 55 | struct fdtable __rcu *fdt; |
9f3acc31 AV |
56 | struct fdtable fdtab; |
57 | /* | |
58 | * written part on a separate cache line in SMP | |
59 | */ | |
60 | spinlock_t file_lock ____cacheline_aligned_in_smp; | |
9b80a184 | 61 | unsigned int next_fd; |
1fd36adc DH |
62 | unsigned long close_on_exec_init[1]; |
63 | unsigned long open_fds_init[1]; | |
f3f86e33 | 64 | unsigned long full_fds_bits_init[1]; |
4d2deb40 | 65 | struct file __rcu * fd_array[NR_OPEN_DEFAULT]; |
9f3acc31 AV |
66 | }; |
67 | ||
9f3acc31 AV |
68 | struct file_operations; |
69 | struct vfsmount; | |
70 | struct dentry; | |
71 | ||
a8d4b834 ON |
72 | #define rcu_dereference_check_fdtable(files, fdtfd) \ |
73 | rcu_dereference_check((fdtfd), lockdep_is_held(&(files)->file_lock)) | |
74 | ||
75 | #define files_fdtable(files) \ | |
76 | rcu_dereference_check_fdtable((files), (files)->fdt) | |
77 | ||
78 | /* | |
79 | * The caller must ensure that fd table isn't shared or hold rcu or file lock | |
80 | */ | |
81 | static inline struct file *__fcheck_files(struct files_struct *files, unsigned int fd) | |
9f3acc31 | 82 | { |
a8d4b834 | 83 | struct fdtable *fdt = rcu_dereference_raw(files->fdt); |
9f3acc31 AV |
84 | |
85 | if (fd < fdt->max_fds) | |
a8d4b834 ON |
86 | return rcu_dereference_raw(fdt->fd[fd]); |
87 | return NULL; | |
88 | } | |
89 | ||
90 | static inline struct file *fcheck_files(struct files_struct *files, unsigned int fd) | |
91 | { | |
f78f5b90 PM |
92 | RCU_LOCKDEP_WARN(!rcu_read_lock_held() && |
93 | !lockdep_is_held(&files->file_lock), | |
a8d4b834 ON |
94 | "suspicious rcu_dereference_check() usage"); |
95 | return __fcheck_files(files, fd); | |
9f3acc31 AV |
96 | } |
97 | ||
98 | /* | |
99 | * Check whether the specified fd has an open file. | |
100 | */ | |
101 | #define fcheck(fd) fcheck_files(current->files, fd) | |
102 | ||
103 | struct task_struct; | |
104 | ||
105 | struct files_struct *get_files_struct(struct task_struct *); | |
106 | void put_files_struct(struct files_struct *fs); | |
107 | void reset_files_struct(struct files_struct *); | |
108 | int unshare_files(struct files_struct **); | |
0766f788 | 109 | struct files_struct *dup_fd(struct files_struct *, int *) __latent_entropy; |
6a6d27de | 110 | void do_close_on_exec(struct files_struct *); |
c3c073f8 AV |
111 | int iterate_fd(struct files_struct *, unsigned, |
112 | int (*)(const void *, struct file *, unsigned), | |
113 | const void *); | |
9f3acc31 | 114 | |
dcfadfa4 AV |
115 | extern int __alloc_fd(struct files_struct *files, |
116 | unsigned start, unsigned end, unsigned flags); | |
f869e8a7 AV |
117 | extern void __fd_install(struct files_struct *files, |
118 | unsigned int fd, struct file *file); | |
483ce1d4 AV |
119 | extern int __close_fd(struct files_struct *files, |
120 | unsigned int fd); | |
dcfadfa4 | 121 | |
9f3acc31 AV |
122 | extern struct kmem_cache *files_cachep; |
123 | ||
124 | #endif /* __LINUX_FDTABLE_H */ |