1 #ifndef _LINUX_POLL_H
2 #define _LINUX_POLL_H
3
4 #include <asm/poll.h>
5
6 #ifdef __KERNEL__
7
8 #include <linux/compiler.h>
9 #include <linux/ktime.h>
10 #include <linux/wait.h>
11 #include <linux/string.h>
12 #include <linux/fs.h>
13 #include <linux/sysctl.h>
14 #include <asm/uaccess.h>
15
16 extern struct ctl_table epoll_table[]; /* for sysctl */
17 /* ~832 bytes of stack space used max in sys_select/sys_poll before allocating
18 additional memory. */
19 #define MAX_STACK_ALLOC 832
20 #define FRONTEND_STACK_ALLOC 256
21 #define SELECT_STACK_ALLOC FRONTEND_STACK_ALLOC
22 #define POLL_STACK_ALLOC FRONTEND_STACK_ALLOC
23 #define WQUEUES_STACK_ALLOC (MAX_STACK_ALLOC - FRONTEND_STACK_ALLOC)
24 #define N_INLINE_POLL_ENTRIES (WQUEUES_STACK_ALLOC / sizeof(struct poll_table_entry))
25
26 #define DEFAULT_POLLMASK (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)
27
28 struct poll_table_struct;
29
30 /*
31 * structures and helpers for f_op->poll implementations
32 */
33 typedef void (*poll_queue_proc)(struct file *, wait_queue_head_t *, struct poll_table_struct *);
34
35 typedef struct poll_table_struct {
36 poll_queue_proc qproc;
37 unsigned long key;
38 } poll_table;
39
poll_wait(struct file * filp,wait_queue_head_t * wait_address,poll_table * p)40 static inline void poll_wait(struct file * filp, wait_queue_head_t * wait_address, poll_table *p)
41 {
42 if (p && wait_address)
43 p->qproc(filp, wait_address, p);
44 }
45
init_poll_funcptr(poll_table * pt,poll_queue_proc qproc)46 static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc)
47 {
48 pt->qproc = qproc;
49 pt->key = ~0UL; /* all events enabled */
50 }
51
52 struct poll_table_entry {
53 struct file *filp;
54 unsigned long key;
55 wait_queue_t wait;
56 wait_queue_head_t *wait_address;
57 };
58
59 /*
60 * Structures and helpers for select/poll syscall
61 */
62 struct poll_wqueues {
63 poll_table pt;
64 struct poll_table_page *table;
65 struct task_struct *polling_task;
66 int triggered;
67 int error;
68 int inline_index;
69 struct poll_table_entry inline_entries[N_INLINE_POLL_ENTRIES];
70 };
71
72 extern void poll_initwait(struct poll_wqueues *pwq);
73 extern void poll_freewait(struct poll_wqueues *pwq);
74 extern int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
75 ktime_t *expires, unsigned long slack);
76 extern long select_estimate_accuracy(struct timespec *tv);
77
78
poll_schedule(struct poll_wqueues * pwq,int state)79 static inline int poll_schedule(struct poll_wqueues *pwq, int state)
80 {
81 return poll_schedule_timeout(pwq, state, NULL, 0);
82 }
83
84 /*
85 * Scalable version of the fd_set.
86 */
87
88 typedef struct {
89 unsigned long *in, *out, *ex;
90 unsigned long *res_in, *res_out, *res_ex;
91 } fd_set_bits;
92
93 /*
94 * How many longwords for "nr" bits?
95 */
96 #define FDS_BITPERLONG (8*sizeof(long))
97 #define FDS_LONGS(nr) (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG)
98 #define FDS_BYTES(nr) (FDS_LONGS(nr)*sizeof(long))
99
100 /*
101 * We do a VERIFY_WRITE here even though we are only reading this time:
102 * we'll write to it eventually..
103 *
104 * Use "unsigned long" accesses to let user-mode fd_set's be long-aligned.
105 */
106 static inline
get_fd_set(unsigned long nr,void __user * ufdset,unsigned long * fdset)107 int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
108 {
109 nr = FDS_BYTES(nr);
110 if (ufdset)
111 return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0;
112
113 memset(fdset, 0, nr);
114 return 0;
115 }
116
117 static inline unsigned long __must_check
set_fd_set(unsigned long nr,void __user * ufdset,unsigned long * fdset)118 set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
119 {
120 if (ufdset)
121 return __copy_to_user(ufdset, fdset, FDS_BYTES(nr));
122 return 0;
123 }
124
125 static inline
zero_fd_set(unsigned long nr,unsigned long * fdset)126 void zero_fd_set(unsigned long nr, unsigned long *fdset)
127 {
128 memset(fdset, 0, FDS_BYTES(nr));
129 }
130
131 #define MAX_INT64_SECONDS (((s64)(~((u64)0)>>1)/HZ)-1)
132
133 extern int do_select(int n, fd_set_bits *fds, struct timespec *end_time);
134 extern int do_sys_poll(struct pollfd __user * ufds, unsigned int nfds,
135 struct timespec *end_time);
136 extern int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
137 fd_set __user *exp, struct timespec *end_time);
138
139 extern int poll_select_set_timeout(struct timespec *to, long sec, long nsec);
140
141 #endif /* KERNEL */
142
143 #endif /* _LINUX_POLL_H */
144