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Commit | Line | Data |
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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> | |
56c30ba7 | 13 | #include <linux/nospec.h> |
9f3acc31 | 14 | #include <linux/types.h> |
21e54459 | 15 | #include <linux/init.h> |
2c666df8 | 16 | #include <linux/fs.h> |
21e54459 | 17 | |
60063497 | 18 | #include <linux/atomic.h> |
9f3acc31 AV |
19 | |
20 | /* | |
21 | * The default fd array needs to be at least BITS_PER_LONG, | |
22 | * as this is the granularity returned by copy_fdset(). | |
23 | */ | |
24 | #define NR_OPEN_DEFAULT BITS_PER_LONG | |
25 | ||
9f3acc31 AV |
26 | struct fdtable { |
27 | unsigned int max_fds; | |
4d2deb40 | 28 | struct file __rcu **fd; /* current fd array */ |
1fd36adc DH |
29 | unsigned long *close_on_exec; |
30 | unsigned long *open_fds; | |
f3f86e33 | 31 | unsigned long *full_fds_bits; |
9f3acc31 | 32 | struct rcu_head rcu; |
9f3acc31 AV |
33 | }; |
34 | ||
9b80a184 | 35 | static inline bool close_on_exec(unsigned int fd, const struct fdtable *fdt) |
1dce27c5 | 36 | { |
1fd36adc | 37 | return test_bit(fd, fdt->close_on_exec); |
1dce27c5 DH |
38 | } |
39 | ||
9b80a184 | 40 | static inline bool fd_is_open(unsigned int fd, const struct fdtable *fdt) |
1dce27c5 | 41 | { |
1fd36adc | 42 | return test_bit(fd, fdt->open_fds); |
1dce27c5 DH |
43 | } |
44 | ||
9f3acc31 AV |
45 | /* |
46 | * Open file table structure | |
47 | */ | |
48 | struct files_struct { | |
49 | /* | |
50 | * read mostly part | |
51 | */ | |
52 | atomic_t count; | |
8a81252b ED |
53 | bool resize_in_progress; |
54 | wait_queue_head_t resize_wait; | |
55 | ||
4d2deb40 | 56 | struct fdtable __rcu *fdt; |
9f3acc31 AV |
57 | struct fdtable fdtab; |
58 | /* | |
59 | * written part on a separate cache line in SMP | |
60 | */ | |
61 | spinlock_t file_lock ____cacheline_aligned_in_smp; | |
9b80a184 | 62 | unsigned int next_fd; |
1fd36adc DH |
63 | unsigned long close_on_exec_init[1]; |
64 | unsigned long open_fds_init[1]; | |
f3f86e33 | 65 | unsigned long full_fds_bits_init[1]; |
4d2deb40 | 66 | struct file __rcu * fd_array[NR_OPEN_DEFAULT]; |
9f3acc31 AV |
67 | }; |
68 | ||
9f3acc31 AV |
69 | struct file_operations; |
70 | struct vfsmount; | |
71 | struct dentry; | |
72 | ||
a8d4b834 ON |
73 | #define rcu_dereference_check_fdtable(files, fdtfd) \ |
74 | rcu_dereference_check((fdtfd), lockdep_is_held(&(files)->file_lock)) | |
75 | ||
76 | #define files_fdtable(files) \ | |
77 | rcu_dereference_check_fdtable((files), (files)->fdt) | |
78 | ||
79 | /* | |
80 | * The caller must ensure that fd table isn't shared or hold rcu or file lock | |
81 | */ | |
82 | static inline struct file *__fcheck_files(struct files_struct *files, unsigned int fd) | |
9f3acc31 | 83 | { |
a8d4b834 | 84 | struct fdtable *fdt = rcu_dereference_raw(files->fdt); |
9f3acc31 | 85 | |
56c30ba7 DW |
86 | if (fd < fdt->max_fds) { |
87 | fd = array_index_nospec(fd, fdt->max_fds); | |
a8d4b834 | 88 | return rcu_dereference_raw(fdt->fd[fd]); |
56c30ba7 | 89 | } |
a8d4b834 ON |
90 | return NULL; |
91 | } | |
92 | ||
93 | static inline struct file *fcheck_files(struct files_struct *files, unsigned int fd) | |
94 | { | |
f78f5b90 PM |
95 | RCU_LOCKDEP_WARN(!rcu_read_lock_held() && |
96 | !lockdep_is_held(&files->file_lock), | |
a8d4b834 ON |
97 | "suspicious rcu_dereference_check() usage"); |
98 | return __fcheck_files(files, fd); | |
9f3acc31 AV |
99 | } |
100 | ||
101 | /* | |
102 | * Check whether the specified fd has an open file. | |
103 | */ | |
104 | #define fcheck(fd) fcheck_files(current->files, fd) | |
105 | ||
106 | struct task_struct; | |
107 | ||
108 | struct files_struct *get_files_struct(struct task_struct *); | |
109 | void put_files_struct(struct files_struct *fs); | |
110 | void reset_files_struct(struct files_struct *); | |
111 | int unshare_files(struct files_struct **); | |
0766f788 | 112 | struct files_struct *dup_fd(struct files_struct *, int *) __latent_entropy; |
6a6d27de | 113 | void do_close_on_exec(struct files_struct *); |
c3c073f8 AV |
114 | int iterate_fd(struct files_struct *, unsigned, |
115 | int (*)(const void *, struct file *, unsigned), | |
116 | const void *); | |
9f3acc31 | 117 | |
dcfadfa4 AV |
118 | extern int __alloc_fd(struct files_struct *files, |
119 | unsigned start, unsigned end, unsigned flags); | |
f869e8a7 AV |
120 | extern void __fd_install(struct files_struct *files, |
121 | unsigned int fd, struct file *file); | |
483ce1d4 AV |
122 | extern int __close_fd(struct files_struct *files, |
123 | unsigned int fd); | |
80cd7956 | 124 | extern int __close_fd_get_file(unsigned int fd, struct file **res); |
dcfadfa4 | 125 | |
9f3acc31 AV |
126 | extern struct kmem_cache *files_cachep; |
127 | ||
128 | #endif /* __LINUX_FDTABLE_H */ |