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 | ||
9b80a184 | 36 | static inline bool close_on_exec(unsigned int fd, const struct fdtable *fdt) |
1dce27c5 | 37 | { |
1fd36adc | 38 | return test_bit(fd, fdt->close_on_exec); |
1dce27c5 DH |
39 | } |
40 | ||
9b80a184 | 41 | static inline bool fd_is_open(unsigned int fd, const struct fdtable *fdt) |
1dce27c5 | 42 | { |
1fd36adc | 43 | return test_bit(fd, fdt->open_fds); |
1dce27c5 DH |
44 | } |
45 | ||
9f3acc31 AV |
46 | /* |
47 | * Open file table structure | |
48 | */ | |
49 | struct files_struct { | |
50 | /* | |
51 | * read mostly part | |
52 | */ | |
53 | atomic_t count; | |
8a81252b ED |
54 | bool resize_in_progress; |
55 | wait_queue_head_t resize_wait; | |
56 | ||
4d2deb40 | 57 | struct fdtable __rcu *fdt; |
9f3acc31 AV |
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; |
1fd36adc DH |
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]; |
9f3acc31 AV |
68 | }; |
69 | ||
9f3acc31 AV |
70 | struct file_operations; |
71 | struct vfsmount; | |
72 | struct dentry; | |
73 | ||
a8d4b834 ON |
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 | 83 | static 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); |
253ca867 LT |
86 | unsigned long mask = array_index_mask_nospec(fd, fdt->max_fds); |
87 | struct file *needs_masking; | |
9f3acc31 | 88 | |
253ca867 LT |
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); | |
a8d4b834 ON |
97 | } |
98 | ||
120ce2b0 EB |
99 | static 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 | ||
0ede61d8 CB |
106 | struct file *lookup_fdget_rcu(unsigned int fd); |
107 | struct file *task_lookup_fdget_rcu(struct task_struct *task, unsigned int fd); | |
108 | struct file *task_lookup_next_fdget_rcu(struct task_struct *task, unsigned int *fd); | |
3a879fb3 | 109 | |
9f3acc31 AV |
110 | struct task_struct; |
111 | ||
9f3acc31 | 112 | void put_files_struct(struct files_struct *fs); |
1f702603 | 113 | int unshare_files(void); |
60997c3d | 114 | struct files_struct *dup_fd(struct files_struct *, unsigned, int *) __latent_entropy; |
6a6d27de | 115 | void do_close_on_exec(struct files_struct *); |
c3c073f8 AV |
116 | int iterate_fd(struct files_struct *, unsigned, |
117 | int (*)(const void *, struct file *, unsigned), | |
118 | const void *); | |
9f3acc31 | 119 | |
8760c909 | 120 | extern int close_fd(unsigned int fd); |
60997c3d | 121 | extern int __close_range(unsigned int fd, unsigned int max_fd, unsigned int flags); |
a88c955f | 122 | extern struct file *file_close_fd(unsigned int fd); |
60997c3d CB |
123 | extern int unshare_fd(unsigned long unshare_flags, unsigned int max_fds, |
124 | struct files_struct **new_fdp); | |
dcfadfa4 | 125 | |
9f3acc31 AV |
126 | extern struct kmem_cache *files_cachep; |
127 | ||
128 | #endif /* __LINUX_FDTABLE_H */ |