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> | |
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 | |
60997c3d | 25 | #define NR_OPEN_MAX ~0U |
9f3acc31 | 26 | |
9f3acc31 AV |
27 | struct fdtable { |
28 | unsigned int max_fds; | |
4d2deb40 | 29 | struct file __rcu **fd; /* current fd array */ |
1fd36adc DH |
30 | unsigned long *close_on_exec; |
31 | unsigned long *open_fds; | |
f3f86e33 | 32 | unsigned long *full_fds_bits; |
9f3acc31 | 33 | struct rcu_head rcu; |
9f3acc31 AV |
34 | }; |
35 | ||
36 | /* | |
37 | * Open file table structure | |
38 | */ | |
39 | struct files_struct { | |
40 | /* | |
41 | * read mostly part | |
42 | */ | |
43 | atomic_t count; | |
8a81252b ED |
44 | bool resize_in_progress; |
45 | wait_queue_head_t resize_wait; | |
46 | ||
4d2deb40 | 47 | struct fdtable __rcu *fdt; |
9f3acc31 AV |
48 | struct fdtable fdtab; |
49 | /* | |
50 | * written part on a separate cache line in SMP | |
51 | */ | |
52 | spinlock_t file_lock ____cacheline_aligned_in_smp; | |
9b80a184 | 53 | unsigned int next_fd; |
1fd36adc DH |
54 | unsigned long close_on_exec_init[1]; |
55 | unsigned long open_fds_init[1]; | |
f3f86e33 | 56 | unsigned long full_fds_bits_init[1]; |
4d2deb40 | 57 | struct file __rcu * fd_array[NR_OPEN_DEFAULT]; |
9f3acc31 AV |
58 | }; |
59 | ||
9f3acc31 AV |
60 | struct file_operations; |
61 | struct vfsmount; | |
62 | struct dentry; | |
63 | ||
a8d4b834 ON |
64 | #define rcu_dereference_check_fdtable(files, fdtfd) \ |
65 | rcu_dereference_check((fdtfd), lockdep_is_held(&(files)->file_lock)) | |
66 | ||
67 | #define files_fdtable(files) \ | |
68 | rcu_dereference_check_fdtable((files), (files)->fdt) | |
69 | ||
70 | /* | |
71 | * The caller must ensure that fd table isn't shared or hold rcu or file lock | |
72 | */ | |
bebf684b | 73 | static inline struct file *files_lookup_fd_raw(struct files_struct *files, unsigned int fd) |
9f3acc31 | 74 | { |
a8d4b834 | 75 | struct fdtable *fdt = rcu_dereference_raw(files->fdt); |
253ca867 LT |
76 | unsigned long mask = array_index_mask_nospec(fd, fdt->max_fds); |
77 | struct file *needs_masking; | |
9f3acc31 | 78 | |
253ca867 LT |
79 | /* |
80 | * 'mask' is zero for an out-of-bounds fd, all ones for ok. | |
81 | * 'fd&mask' is 'fd' for ok, or 0 for out of bounds. | |
82 | * | |
83 | * Accessing fdt->fd[0] is ok, but needs masking of the result. | |
84 | */ | |
85 | needs_masking = rcu_dereference_raw(fdt->fd[fd&mask]); | |
86 | return (struct file *)(mask & (unsigned long)needs_masking); | |
a8d4b834 ON |
87 | } |
88 | ||
120ce2b0 EB |
89 | static inline struct file *files_lookup_fd_locked(struct files_struct *files, unsigned int fd) |
90 | { | |
91 | RCU_LOCKDEP_WARN(!lockdep_is_held(&files->file_lock), | |
92 | "suspicious rcu_dereference_check() usage"); | |
93 | return files_lookup_fd_raw(files, fd); | |
94 | } | |
95 | ||
0ede61d8 CB |
96 | struct file *lookup_fdget_rcu(unsigned int fd); |
97 | struct file *task_lookup_fdget_rcu(struct task_struct *task, unsigned int fd); | |
98 | struct file *task_lookup_next_fdget_rcu(struct task_struct *task, unsigned int *fd); | |
3a879fb3 | 99 | |
f60d374d AV |
100 | static inline bool close_on_exec(unsigned int fd, const struct files_struct *files) |
101 | { | |
102 | return test_bit(fd, files_fdtable(files)->close_on_exec); | |
103 | } | |
104 | ||
9f3acc31 AV |
105 | struct task_struct; |
106 | ||
9f3acc31 | 107 | void put_files_struct(struct files_struct *fs); |
1f702603 | 108 | int unshare_files(void); |
60997c3d | 109 | struct files_struct *dup_fd(struct files_struct *, unsigned, 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 | |
8760c909 | 115 | extern int close_fd(unsigned int fd); |
60997c3d | 116 | extern int __close_range(unsigned int fd, unsigned int max_fd, unsigned int flags); |
a88c955f | 117 | extern struct file *file_close_fd(unsigned int fd); |
60997c3d CB |
118 | extern int unshare_fd(unsigned long unshare_flags, unsigned int max_fds, |
119 | struct files_struct **new_fdp); | |
dcfadfa4 | 120 | |
9f3acc31 AV |
121 | extern struct kmem_cache *files_cachep; |
122 | ||
123 | #endif /* __LINUX_FDTABLE_H */ |