git.ozlabs.org Git - petitboot/blob - lib/waiter/waiter.c

   1
   2 #include <poll.h>
   3 #include <string.h>
   4 #include <assert.h>
   5
   6 #include <talloc/talloc.h>
   7
   8 #include "waiter.h"
   9
  10 struct waiter {
  11         int             fd;
  12         int             events;
  13         waiter_cb       callback;
  14         void            *arg;
  15 };
  16
  17 static struct waiter *waiters;
  18 static int n_waiters;
  19
  20 struct waiter *waiter_register(int fd, int events,
  21                 waiter_cb callback, void *arg)
  22 {
  23         struct waiter *waiter;
  24
  25         n_waiters++;
  26
  27         waiters = talloc_realloc(NULL, waiters, struct waiter, n_waiters);
  28
  29         if(!waiters)
  30                 return NULL;
  31
  32         waiter = &waiters[n_waiters - 1];
  33
  34         waiter->fd = fd;
  35         waiter->events = events;
  36         waiter->callback = callback;
  37         waiter->arg = arg;
  38
  39         return waiter;
  40 }
  41
  42 void waiter_remove(struct waiter *waiter)
  43 {
  44         int i;
  45
  46         i = waiter - waiters;
  47         assert(i >= 0 && i < n_waiters);
  48
  49         n_waiters--;
  50         memmove(&waiters[i], &waiters[i+1],
  51                 (n_waiters - i) * sizeof(waiters[0]));
  52
  53         waiters = talloc_realloc(NULL, waiters, struct waiter, n_waiters);
  54 }
  55
  56 int waiter_poll(void)
  57 {
  58         static struct pollfd *pollfds;
  59         static int n_pollfds;
  60         int i, rc;
  61
  62         if (n_waiters != n_pollfds) {
  63                 pollfds = talloc_realloc(NULL, pollfds,
  64                                 struct pollfd, n_waiters);
  65                 n_pollfds = n_waiters;
  66         }
  67
  68         for (i = 0; i < n_waiters; i++) {
  69                 pollfds[i].fd = waiters[i].fd;
  70                 pollfds[i].events = waiters[i].events;
  71                 pollfds[i].revents = 0;
  72         }
  73
  74         rc = poll(pollfds, n_waiters, -1);
  75
  76         if (rc <= 0)
  77                 return rc;
  78
  79         for (i = 0; i < n_waiters; i++) {
  80                 if (pollfds[i].revents) {
  81                         rc = waiters[i].callback(waiters[i].arg);
  82
  83                         if (rc)
  84                                 waiter_remove(&waiters[i]);
  85                 }
  86         }
  87
  88         return 0;
  89 }