]> git.ozlabs.org Git - petitboot/blobdiff - lib/waiter/waiter.c
lib/waiter: fix talloc_realloc context
[petitboot] / lib / waiter / waiter.c
index 78ba045f8b18fe5088d8c11422175b4654f87752..13b0d68fc05ac6a32a03aea748377d0da03c226e 100644 (file)
@@ -3,17 +3,31 @@
 #include <stdbool.h>
 #include <string.h>
 #include <assert.h>
+#include <sys/time.h>
 
 #include <talloc/talloc.h>
+#include <list/list.h>
 
 #include "waiter.h"
 
 struct waiter {
        struct waitset  *set;
-       int             fd;
-       int             events;
+       enum {
+               WAITER_IO,
+               WAITER_TIME,
+       } type;
+       union {
+               struct {
+                       int     fd;
+                       int     events;
+               } io;
+               struct timeval  timeout;
+       };
        waiter_cb       callback;
        void            *arg;
+
+       bool                    active;
+       struct list_item        list;
 };
 
 struct waitset {
@@ -21,17 +35,25 @@ struct waitset {
        int             n_waiters;
        bool            waiters_changed;
 
+       struct timeval  next_timeout;
+
        /* These are kept consistent over each call to waiter_poll, as
         * set->waiters may be updated (by waiters' callbacks calling
         * waiter_register or waiter_remove) during iteration. */
        struct pollfd   *pollfds;
-       struct waiter   **cur_waiters;
-       int             cur_n_waiters;
+       int             n_pollfds;
+       struct waiter   **io_waiters;
+       int             n_io_waiters;
+       struct waiter   **time_waiters;
+       int             n_time_waiters;
+
+       struct list     free_list;
 };
 
 struct waitset *waitset_create(void *ctx)
 {
        struct waitset *set = talloc_zero(ctx, struct waitset);
+       list_init(&set->free_list);
        return set;
 }
 
@@ -40,8 +62,7 @@ void waitset_destroy(struct waitset *set)
        talloc_free(set);
 }
 
-struct waiter *waiter_register(struct waitset *set, int fd, int events,
-               waiter_cb callback, void *arg)
+static struct waiter *waiter_new(struct waitset *set)
 {
        struct waiter **waiters, *waiter;
 
@@ -62,10 +83,40 @@ struct waiter *waiter_register(struct waitset *set, int fd, int events,
        set->n_waiters++;
 
        set->waiters[set->n_waiters - 1] = waiter;
+       waiter->active = true;
+       return waiter;
+}
+
+struct waiter *waiter_register_io(struct waitset *set, int fd, int events,
+               waiter_cb callback, void *arg)
+{
+       struct waiter *waiter = waiter_new(set);
+
+       waiter->type = WAITER_IO;
+       waiter->set = set;
+       waiter->io.fd = fd;
+       waiter->io.events = events;
+       waiter->callback = callback;
+       waiter->arg = arg;
+
+       return waiter;
+}
+
+struct waiter *waiter_register_timeout(struct waitset *set, int delay_ms,
+               waiter_cb callback, void *arg)
+{
+       struct waiter *waiter = waiter_new(set);
+       struct timeval now, delay;
+
+       delay.tv_sec = delay_ms / 1000;
+       delay.tv_usec = 1000 * (delay_ms % 1000);
+
+       gettimeofday(&now, NULL);
 
+       timeradd(&now, &delay, &waiter->timeout);
+
+       waiter->type = WAITER_TIME;
        waiter->set = set;
-       waiter->fd = fd;
-       waiter->events = events;
        waiter->callback = callback;
        waiter->arg = arg;
 
@@ -87,55 +138,139 @@ void waiter_remove(struct waiter *waiter)
        memmove(&set->waiters[i], &set->waiters[i+1],
                (set->n_waiters - i) * sizeof(set->waiters[0]));
 
-       set->waiters = talloc_realloc(set->waiters, set->waiters,
+       set->waiters = talloc_realloc(set, set->waiters,
                        struct waiter *, set->n_waiters);
        set->waiters_changed = true;
 
-       talloc_free(waiter);
+       waiter->active = false;
+       list_add(&set->free_list, &waiter->list);
+}
+
+static void update_waiters(struct waitset *set)
+{
+       int n_io, n_time, i_io, i_time, i;
+
+       if (!set->waiters_changed)
+               return;
+
+       n_io = n_time = 0;
+
+       for (i = 0; i < set->n_waiters; i++) {
+               if (set->waiters[i]->type == WAITER_IO)
+                       n_io++;
+               else if (set->waiters[i]->type == WAITER_TIME)
+                       n_time++;
+       }
+
+       /* realloc if counts have changed */
+       if (set->n_io_waiters != n_io) {
+               set->io_waiters = talloc_realloc(set, set->io_waiters,
+                               struct waiter *, n_io);
+               set->pollfds = talloc_realloc(set, set->pollfds,
+                               struct pollfd, n_io);
+               set->n_io_waiters = n_io;
+       }
+       if (set->n_time_waiters != n_time) {
+               set->time_waiters = talloc_realloc(set, set->time_waiters,
+                               struct waiter *, n_time);
+               set->n_time_waiters = n_time;
+       }
+
+       i_io = 0;
+       i_time = 0;
+
+       timerclear(&set->next_timeout);
+
+       for (i = 0; i < set->n_waiters; i++) {
+               struct waiter *waiter = set->waiters[i];
+
+               /* IO waiters: copy to io_waiters, populate pollfds */
+               if (waiter->type == WAITER_IO) {
+                       set->pollfds[i_io].fd = waiter->io.fd;
+                       set->pollfds[i_io].events = waiter->io.events;
+                       set->io_waiters[i_io] = waiter;
+                       i_io++;
+               }
+
+               /* time waiters: copy to time_waiters, calculate next expiry */
+               if (waiter->type == WAITER_TIME) {
+                       if (!timerisset(&set->next_timeout) ||
+                                       timercmp(&waiter->timeout,
+                                               &set->next_timeout, <))
+                               set->next_timeout = waiter->timeout;
+
+                       set->time_waiters[i_time] = waiter;
+                       i_time++;
+               }
+       }
 }
 
 int waiter_poll(struct waitset *set)
 {
+       struct timeval now, timeout;
+       struct waiter *waiter, *tmp;
+       int timeout_ms;
        int i, rc;
 
        /* If the waiters have been updated, we need to update our
         * consistent copy */
-       if (set->waiters_changed) {
-
-               /* We need to reallocate if the count has changes */
-               if (set->cur_n_waiters != set->n_waiters) {
-                       set->cur_waiters = talloc_realloc(set, set->cur_waiters,
-                                       struct waiter *, set->n_waiters);
-                       set->pollfds = talloc_realloc(set, set->pollfds,
-                                       struct pollfd, set->n_waiters);
-                       set->cur_n_waiters = set->n_waiters;
-               }
+       update_waiters(set);
+
+       if (timerisset(&set->next_timeout)) {
+               gettimeofday(&now, NULL);
+               timersub(&set->next_timeout, &now, &timeout);
+               timeout_ms = timeout.tv_sec * 1000 +
+                               timeout.tv_usec / 1000;
+               if (timeout_ms < 0)
+                       timeout_ms = 0;
+       } else {
+               timeout_ms = -1;
+       }
 
-               /* Populate cur_waiters and pollfds from ->waiters data */
-               for (i = 0; i < set->n_waiters; i++) {
-                       set->pollfds[i].fd = set->waiters[i]->fd;
-                       set->pollfds[i].events = set->waiters[i]->events;
-                       set->pollfds[i].revents = 0;
-                       set->cur_waiters[i] = set->waiters[i];
-               }
 
-               set->waiters_changed = false;
+       rc = poll(set->pollfds, set->n_io_waiters, timeout_ms);
+
+       if (rc < 0)
+               goto out;
+
+       for (i = 0; i < set->n_io_waiters; i++) {
+               struct waiter *waiter = set->io_waiters[i];
+
+               if (!waiter->active)
+                       continue;
+
+               if (!set->pollfds[i].revents)
+                       continue;
+               rc = waiter->callback(waiter->arg);
+
+               if (rc)
+                       waiter_remove(waiter);
        }
 
-       rc = poll(set->pollfds, set->cur_n_waiters, -1);
+       if (set->n_time_waiters > 0)
+               gettimeofday(&now, NULL);
 
-       if (rc <= 0)
-               return rc;
+       for (i = 0; i < set->n_time_waiters; i++) {
+               struct waiter *waiter = set->time_waiters[i];
 
-       for (i = 0; i < set->cur_n_waiters; i++) {
-               if (set->pollfds[i].revents) {
-                       rc = set->cur_waiters[i]->callback(
-                                       set->cur_waiters[i]->arg);
+               if (!waiter->active)
+                       continue;
 
-                       if (rc)
-                               waiter_remove(set->cur_waiters[i]);
-               }
+               if (timercmp(&waiter->timeout, &now, >))
+                       continue;
+
+               waiter->callback(waiter->arg);
+
+               waiter_remove(waiter);
        }
 
-       return 0;
+       rc = 0;
+
+out:
+       /* free any waiters that have been removed */
+       list_for_each_entry_safe(&set->free_list, waiter, tmp, list)
+               talloc_free(waiter);
+       list_init(&set->free_list);
+
+       return rc;
 }