include/linux/poll.h

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