1 files changed, 151 insertions, 0 deletions
diff --git a/src/knot/common/fdset.c b/src/knot/common/fdset.c
new file mode 100644
index 0000000..bb83670
--- /dev/null
+++ b/src/knot/common/fdset.c
@@ -0,0 +1,151 @@
+/*  Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <time.h>
+#include "knot/common/fdset.h"
+#include "contrib/time.h"
+#include "libknot/errcode.h"
+
+/* Realloc memory or return error (part of fdset_resize). */
+#define MEM_RESIZE(tmp, p, n) \
+	if ((tmp = realloc((p), (n) * sizeof(*p))) == NULL) \
+		return KNOT_ENOMEM; \
+	(p) = tmp;
+
+static int fdset_resize(fdset_t *set, unsigned size)
+{
+	void *tmp = NULL;
+	MEM_RESIZE(tmp, set->ctx, size);
+	MEM_RESIZE(tmp, set->pfd, size);
+	MEM_RESIZE(tmp, set->timeout, size);
+	set->size = size;
+	return KNOT_EOK;
+}
+
+int fdset_init(fdset_t *set, unsigned size)
+{
+	if (set == NULL) {
+		return KNOT_EINVAL;
+	}
+
+	memset(set, 0, sizeof(fdset_t));
+	return fdset_resize(set, size);
+}
+
+int fdset_clear(fdset_t* set)
+{
+	if (set == NULL) {
+		return KNOT_EINVAL;
+	}
+
+	free(set->ctx);
+	free(set->pfd);
+	free(set->timeout);
+	memset(set, 0, sizeof(fdset_t));
+	return KNOT_EOK;
+}
+
+int fdset_add(fdset_t *set, int fd, unsigned events, void *ctx)
+{
+	if (set == NULL || fd < 0) {
+		return KNOT_EINVAL;
+	}
+
+	/* Realloc needed. */
+	if (set->n == set->size && fdset_resize(set, set->size + FDSET_INIT_SIZE))
+		return KNOT_ENOMEM;
+
+	/* Initialize. */
+	int i = set->n++;
+	set->pfd[i].fd = fd;
+	set->pfd[i].events = events;
+	set->pfd[i].revents = 0;
+	set->ctx[i] = ctx;
+	set->timeout[i] = 0;
+
+	/* Return index to this descriptor. */
+	return i;
+}
+
+int fdset_remove(fdset_t *set, unsigned i)
+{
+	if (set == NULL || i >= set->n) {
+		return KNOT_EINVAL;
+	}
+
+	/* Decrement number of elms. */
+	--set->n;
+
+	/* Nothing else if it is the last one.
+	 * Move last -> i if some remain. */
+	unsigned last = set->n; /* Already decremented */
+	if (i < last) {
+		set->pfd[i] = set->pfd[last];
+		set->timeout[i] = set->timeout[last];
+		set->ctx[i] = set->ctx[last];
+	}
+
+	return KNOT_EOK;
+}
+
+int fdset_set_watchdog(fdset_t* set, int i, int interval)
+{
+	if (set == NULL || i >= set->n) {
+		return KNOT_EINVAL;
+	}
+
+	/* Lift watchdog if interval is negative. */
+	if (interval < 0) {
+		set->timeout[i] = 0;
+		return KNOT_EOK;
+	}
+
+	/* Update clock. */
+	struct timespec now = time_now();
+
+	set->timeout[i] = now.tv_sec + interval; /* Only seconds precision. */
+	return KNOT_EOK;
+}
+
+int fdset_sweep(fdset_t* set, fdset_sweep_cb_t cb, void *data)
+{
+	if (set == NULL || cb == NULL) {
+		return KNOT_EINVAL;
+	}
+
+	/* Get time threshold. */
+	struct timespec now = time_now();
+
+	unsigned i = 0;
+	while (i < set->n) {
+
+		/* Check sweep state, remove if requested. */
+		if (set->timeout[i] > 0 && set->timeout[i] <= now.tv_sec) {
+			if (cb(set, i, data) == FDSET_SWEEP) {
+				if (fdset_remove(set, i) == KNOT_EOK)
+					continue; /* Stay on the index. */
+			}
+		}
+
+		/* Next descriptor. */
+		++i;
+	}
+
+	return KNOT_EOK;
+}