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         struct waitset  *set;
  12         int             fd;
  13         int             events;
  14         waiter_cb       callback;
  15         void            *arg;
  16 };
  17
  18 struct waitset {
  19         struct waiter   **waiters;
  20         int             n_waiters;
  21         struct pollfd   *pollfds;
  22         int             n_pollfds;
  23 };
  24
  25 struct waitset *waitset_create(void *ctx)
  26 {
  27         struct waitset *set = talloc_zero(ctx, struct waitset);
  28         return set;
  29 }
  30
  31 void waitset_destroy(struct waitset *set)
  32 {
  33         talloc_free(set);
  34 }
  35
  36 struct waiter *waiter_register(struct waitset *set, int fd, int events,
  37                 waiter_cb callback, void *arg)
  38 {
  39         struct waiter **waiters, *waiter;
  40
  41         waiters = talloc_realloc(set, set->waiters,
  42                         struct waiter *, set->n_waiters + 1);
  43
  44         if (!waiters)
  45                 return NULL;
  46
  47         set->waiters = waiters;
  48         set->n_waiters++;
  49
  50         waiter = talloc(set->waiters, struct waiter);
  51         if (!waiter)
  52                 return NULL;
  53
  54         set->waiters[set->n_waiters - 1] = waiter;
  55
  56         waiter->set = set;
  57         waiter->fd = fd;
  58         waiter->events = events;
  59         waiter->callback = callback;
  60         waiter->arg = arg;
  61
  62         return waiter;
  63 }
  64
  65 void waiter_remove(struct waiter *waiter)
  66 {
  67         struct waitset *set = waiter->set;
  68         int i;
  69
  70         for (i = 0; i < set->n_waiters; i++)
  71                 if (set->waiters[i] == waiter)
  72                         break;
  73
  74         assert(i < set->n_waiters);
  75
  76         set->n_waiters--;
  77         memmove(&set->waiters[i], &set->waiters[i+1],
  78                 (set->n_waiters - i) * sizeof(set->waiters[0]));
  79
  80         set->waiters = talloc_realloc(set->waiters, set->waiters,
  81                         struct waiter *, set->n_waiters);
  82
  83         talloc_free(waiter);
  84 }
  85
  86 int waiter_poll(struct waitset *set)
  87 {
  88         int i, rc;
  89
  90         if (set->n_waiters != set->n_pollfds) {
  91                 set->pollfds = talloc_realloc(set, set->pollfds,
  92                                 struct pollfd, set->n_waiters);
  93                 set->n_pollfds = set->n_waiters;
  94         }
  95
  96         for (i = 0; i < set->n_waiters; i++) {
  97                 set->pollfds[i].fd = set->waiters[i]->fd;
  98                 set->pollfds[i].events = set->waiters[i]->events;
  99                 set->pollfds[i].revents = 0;
 100         }
 101
 102         rc = poll(set->pollfds, set->n_waiters, -1);
 103
 104         if (rc <= 0)
 105                 return rc;
 106
 107         for (i = 0; i < set->n_waiters; i++) {
 108                 if (set->pollfds[i].revents) {
 109                         rc = set->waiters[i]->callback(set->waiters[i]->arg);
 110
 111                         if (rc)
 112                                 waiter_remove(set->waiters[i]);
 113                 }
 114         }
 115
 116         return 0;
 117 }