Commit | Line | Data |
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9f3acc31 AV |
1 | /* |
2 | * descriptor table internals; you almost certainly want file.h instead. | |
3 | */ | |
4 | ||
5 | #ifndef __LINUX_FDTABLE_H | |
6 | #define __LINUX_FDTABLE_H | |
7 | ||
8 | #include <asm/atomic.h> | |
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> | |
14 | ||
15 | /* | |
16 | * The default fd array needs to be at least BITS_PER_LONG, | |
17 | * as this is the granularity returned by copy_fdset(). | |
18 | */ | |
19 | #define NR_OPEN_DEFAULT BITS_PER_LONG | |
20 | ||
21 | /* | |
22 | * The embedded_fd_set is a small fd_set, | |
23 | * suitable for most tasks (which open <= BITS_PER_LONG files) | |
24 | */ | |
25 | struct embedded_fd_set { | |
26 | unsigned long fds_bits[1]; | |
27 | }; | |
28 | ||
29 | struct fdtable { | |
30 | unsigned int max_fds; | |
31 | struct file ** fd; /* current fd array */ | |
32 | fd_set *close_on_exec; | |
33 | fd_set *open_fds; | |
34 | struct rcu_head rcu; | |
35 | struct fdtable *next; | |
36 | }; | |
37 | ||
38 | /* | |
39 | * Open file table structure | |
40 | */ | |
41 | struct files_struct { | |
42 | /* | |
43 | * read mostly part | |
44 | */ | |
45 | atomic_t count; | |
46 | struct fdtable *fdt; | |
47 | struct fdtable fdtab; | |
48 | /* | |
49 | * written part on a separate cache line in SMP | |
50 | */ | |
51 | spinlock_t file_lock ____cacheline_aligned_in_smp; | |
52 | int next_fd; | |
53 | struct embedded_fd_set close_on_exec_init; | |
54 | struct embedded_fd_set open_fds_init; | |
55 | struct file * fd_array[NR_OPEN_DEFAULT]; | |
56 | }; | |
57 | ||
58 | #define files_fdtable(files) (rcu_dereference((files)->fdt)) | |
59 | ||
60 | extern struct kmem_cache *filp_cachep; | |
61 | ||
62 | struct file_operations; | |
63 | struct vfsmount; | |
64 | struct dentry; | |
65 | ||
66 | extern int expand_files(struct files_struct *, int nr); | |
67 | extern void free_fdtable_rcu(struct rcu_head *rcu); | |
68 | extern void __init files_defer_init(void); | |
69 | ||
70 | static inline void free_fdtable(struct fdtable *fdt) | |
71 | { | |
72 | call_rcu(&fdt->rcu, free_fdtable_rcu); | |
73 | } | |
74 | ||
75 | static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd) | |
76 | { | |
77 | struct file * file = NULL; | |
78 | struct fdtable *fdt = files_fdtable(files); | |
79 | ||
80 | if (fd < fdt->max_fds) | |
81 | file = rcu_dereference(fdt->fd[fd]); | |
82 | return file; | |
83 | } | |
84 | ||
85 | /* | |
86 | * Check whether the specified fd has an open file. | |
87 | */ | |
88 | #define fcheck(fd) fcheck_files(current->files, fd) | |
89 | ||
90 | struct task_struct; | |
91 | ||
92 | struct files_struct *get_files_struct(struct task_struct *); | |
93 | void put_files_struct(struct files_struct *fs); | |
94 | void reset_files_struct(struct files_struct *); | |
95 | int unshare_files(struct files_struct **); | |
02afc626 | 96 | struct files_struct *dup_fd(struct files_struct *, int *); |
9f3acc31 AV |
97 | |
98 | extern struct kmem_cache *files_cachep; | |
99 | ||
100 | #endif /* __LINUX_FDTABLE_H */ |