Merge tag 'perf-tools-fixes-for-v6.9-2024-04-19' of git://git.kernel.org/pub/scm...
[linux-2.6-block.git] / include / linux / fdtable.h
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b2441318 1/* SPDX-License-Identifier: GPL-2.0 */
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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
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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>
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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
60997c3d 25#define NR_OPEN_MAX ~0U
9f3acc31 26
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27struct fdtable {
28 unsigned int max_fds;
4d2deb40 29 struct file __rcu **fd; /* current fd array */
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30 unsigned long *close_on_exec;
31 unsigned long *open_fds;
f3f86e33 32 unsigned long *full_fds_bits;
9f3acc31 33 struct rcu_head rcu;
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34};
35
9b80a184 36static inline bool close_on_exec(unsigned int fd, const struct fdtable *fdt)
1dce27c5 37{
1fd36adc 38 return test_bit(fd, fdt->close_on_exec);
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39}
40
9b80a184 41static inline bool fd_is_open(unsigned int fd, const struct fdtable *fdt)
1dce27c5 42{
1fd36adc 43 return test_bit(fd, fdt->open_fds);
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44}
45
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46/*
47 * Open file table structure
48 */
49struct files_struct {
50 /*
51 * read mostly part
52 */
53 atomic_t count;
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54 bool resize_in_progress;
55 wait_queue_head_t resize_wait;
56
4d2deb40 57 struct fdtable __rcu *fdt;
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58 struct fdtable fdtab;
59 /*
60 * written part on a separate cache line in SMP
61 */
62 spinlock_t file_lock ____cacheline_aligned_in_smp;
9b80a184 63 unsigned int next_fd;
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64 unsigned long close_on_exec_init[1];
65 unsigned long open_fds_init[1];
f3f86e33 66 unsigned long full_fds_bits_init[1];
4d2deb40 67 struct file __rcu * fd_array[NR_OPEN_DEFAULT];
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68};
69
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70struct file_operations;
71struct vfsmount;
72struct dentry;
73
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74#define rcu_dereference_check_fdtable(files, fdtfd) \
75 rcu_dereference_check((fdtfd), lockdep_is_held(&(files)->file_lock))
76
77#define files_fdtable(files) \
78 rcu_dereference_check_fdtable((files), (files)->fdt)
79
80/*
81 * The caller must ensure that fd table isn't shared or hold rcu or file lock
82 */
bebf684b 83static inline struct file *files_lookup_fd_raw(struct files_struct *files, unsigned int fd)
9f3acc31 84{
a8d4b834 85 struct fdtable *fdt = rcu_dereference_raw(files->fdt);
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86 unsigned long mask = array_index_mask_nospec(fd, fdt->max_fds);
87 struct file *needs_masking;
9f3acc31 88
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89 /*
90 * 'mask' is zero for an out-of-bounds fd, all ones for ok.
91 * 'fd&mask' is 'fd' for ok, or 0 for out of bounds.
92 *
93 * Accessing fdt->fd[0] is ok, but needs masking of the result.
94 */
95 needs_masking = rcu_dereference_raw(fdt->fd[fd&mask]);
96 return (struct file *)(mask & (unsigned long)needs_masking);
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97}
98
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99static inline struct file *files_lookup_fd_locked(struct files_struct *files, unsigned int fd)
100{
101 RCU_LOCKDEP_WARN(!lockdep_is_held(&files->file_lock),
102 "suspicious rcu_dereference_check() usage");
103 return files_lookup_fd_raw(files, fd);
104}
105
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106struct file *lookup_fdget_rcu(unsigned int fd);
107struct file *task_lookup_fdget_rcu(struct task_struct *task, unsigned int fd);
108struct file *task_lookup_next_fdget_rcu(struct task_struct *task, unsigned int *fd);
3a879fb3 109
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110struct task_struct;
111
9f3acc31 112void put_files_struct(struct files_struct *fs);
1f702603 113int unshare_files(void);
60997c3d 114struct files_struct *dup_fd(struct files_struct *, unsigned, int *) __latent_entropy;
6a6d27de 115void do_close_on_exec(struct files_struct *);
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116int iterate_fd(struct files_struct *, unsigned,
117 int (*)(const void *, struct file *, unsigned),
118 const void *);
9f3acc31 119
8760c909 120extern int close_fd(unsigned int fd);
60997c3d 121extern int __close_range(unsigned int fd, unsigned int max_fd, unsigned int flags);
a88c955f 122extern struct file *file_close_fd(unsigned int fd);
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123extern int unshare_fd(unsigned long unshare_flags, unsigned int max_fds,
124 struct files_struct **new_fdp);
dcfadfa4 125
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126extern struct kmem_cache *files_cachep;
127
128#endif /* __LINUX_FDTABLE_H */