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         waiter = &waiters[n_waiters - 1];
  29
  30         waiter->fd = fd;
  31         waiter->events = events;
  32         waiter->callback = callback;
  33         waiter->arg = arg;
  34
  35         return 0;
  36 }
  37
  38 void waiter_remove(struct waiter *waiter)
  39 {
  40         int i;
  41
  42         i = waiter - waiters;
  43         assert(i >= 0 && i < n_waiters);
  44
  45         n_waiters--;
  46         memmove(&waiters[i], &waiters[i+1],
  47                 (n_waiters - i) * sizeof(waiters[0]));
  48
  49         waiters = talloc_realloc(NULL, waiters, struct waiter, n_waiters);
  50 }
  51
  52 int waiter_poll(void)
  53 {
  54         static struct pollfd *pollfds;
  55         static int n_pollfds;
  56         int i, rc;
  57
  58         if (n_waiters != n_pollfds) {
  59                 pollfds = talloc_realloc(NULL, pollfds,
  60                                 struct pollfd, n_waiters);
  61                 n_pollfds = n_waiters;
  62         }
  63
  64         for (i = 0; i < n_waiters; i++) {
  65                 pollfds[i].fd = waiters[i].fd;
  66                 pollfds[i].events = waiters[i].events;
  67                 pollfds[i].revents = 0;
  68         }
  69
  70         rc = poll(pollfds, n_waiters, -1);
  71
  72         if (rc <= 0)
  73                 return rc;
  74
  75         for (i = 0; i < n_waiters; i++) {
  76                 if (pollfds[i].revents) {
  77                         rc = waiters[i].callback(waiters[i].arg);
  78
  79                         if (rc)
  80                                 waiter_remove(&waiters[i]);
  81                 }
  82         }
  83
  84         return 0;
  85 }