Initial commit

Signed-off-by: Jose Bollo <jose.bollo@iot.bzh>

1 files changed, 267 insertions, 0 deletions

diff --git a/src/cyn.c b/src/cyn.c
new file mode 100644
index 0000000..4eb6d9e
--- /dev/null
+++ b/src/cyn.c
@@ -0,0 +1,267 @@
+#define _GNU_SOURCE
+
+
+#include <assert.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+#include <errno.h>
+
+
+#include "db.h"
+#include "queue.h"
+#include "cyn.h"
+
+struct callback
+{
+	struct callback *next;
+	void (*callback)(void *closure);
+	void *closure;
+};
+
+/** locking critical section */
+static const void *lock;
+static struct callback *awaiters;
+static struct callback *observers;
+
+static
+int
+delcb(
+	void (*callback)(void *closure),
+	void *closure,
+	struct callback **head
+) {
+	struct callback *c;
+
+	while((c = *head)) {
+		if (c->callback == callback && c->closure == closure) {
+			*head = c->next;
+			free(c);
+			return 1;
+		}
+		head = &c->next;
+	}
+	return 0;
+}
+
+static
+int
+addcb(
+	void (*callback)(void *closure),
+	void *closure,
+	struct callback **head
+) {
+	struct callback *c;
+
+	c = malloc(sizeof *c);
+	if (c == NULL)
+		return -(errno = ENOMEM);
+	c->callback = callback;
+	c->closure = closure;
+	c->next = *head;
+	*head = c;
+	return 0;
+}
+
+static
+int
+changed(
+) {
+	int rc = db_sync();
+	struct callback *c;
+
+	for (c = observers; c ; c = c->next)
+		c->callback(c->closure);
+	return rc;
+}
+
+int
+cyn_init(
+) {
+	/* TODO: paths? */
+	int rc = db_open("/var/lib/cynara/cynara.names", "/var/lib/cynara/cynara.rules");
+	if (rc == 0 && db_is_empty()) {
+		/* TODO: init? */
+		rc = db_set("System", "*", "*", "*", 1);
+		db_sync();
+	}
+	return rc;
+}
+
+/** enter critical recoverable section */
+int
+cyn_enter(
+	const void *magic
+) {
+	if (lock)
+		return -EBUSY;
+	lock = magic;
+	return 0;
+}
+
+int
+cyn_enter_async(
+	void (*enter_cb)(void *closure),
+	void *closure
+) {
+	if (lock)
+		return addcb(enter_cb, closure, &awaiters);
+
+	lock = closure;
+	enter_cb(closure);
+	return 0;
+}
+
+int
+cyn_enter_async_cancel(
+	void (*enter_cb)(void *closure),
+	void *closure
+) {
+	return delcb(enter_cb, closure, &awaiters);
+}
+
+int
+cyn_on_change_add(
+	void (*on_change_cb)(void *closure),
+	void *closure
+) {
+	return addcb(on_change_cb, closure, &observers);
+}
+
+
+int
+cyn_on_change_remove(
+	void (*on_change_cb)(void *closure),
+	void *closure
+) {
+	return delcb(on_change_cb, closure, &observers);
+}
+
+/** leave critical recoverable section */
+int
+cyn_leave(
+	const void *magic,
+	bool commit
+) {
+	int rc;
+	struct callback *e, **p;
+
+	if (!magic)
+		return -EINVAL;
+	if (!lock)
+		return -EALREADY;
+	if (lock != magic)
+		return -EPERM;
+
+	lock = &lock;
+	if (commit)
+		rc = queue_play() ?: changed();
+	else
+		rc = 0;
+	queue_clear();
+
+	e = awaiters;
+	if (!e)
+		lock = 0;
+	else {
+		p = &awaiters;
+		while(e->next) {
+			p = &e->next;
+			e = *p;
+		}
+		*p = NULL;
+		lock = e->closure;
+		e->callback(e->closure);
+		free(e);
+	}
+
+	return rc;
+}
+
+int
+cyn_set(
+	const char *client,
+	const char *session,
+	const char *user,
+	const char *permission,
+	uint32_t value
+) {
+	if (lock && lock != &lock)
+		return queue_set(client, session, user, permission, value);
+
+	return db_set(client, session, user, permission, value) ?: changed();
+}
+
+int
+cyn_drop(
+	const char *client,
+	const char *session,
+	const char *user,
+	const char *permission
+) {
+	if (lock && lock != &lock)
+		return queue_drop(client, session, user, permission);
+
+	return db_drop(client, session, user, permission) ?: changed();
+}
+
+int
+cyn_test(
+	const char *client,
+	const char *session,
+	const char *user,
+	const char *permission,
+	uint32_t *value
+) {
+	int rc;
+
+	rc = db_test(client, session, user, permission, value);
+	if (rc <= 0)
+		*value = DEFAULT;
+	else
+		rc = 0;
+	return rc;
+}
+
+void
+cyn_list(
+	void *closure,
+	void (*callback)(
+		void *closure,
+		const char *client,
+		const char *session,
+		const char *user,
+		const char *permission,
+		uint32_t value),
+	const char *client,
+	const char *session,
+	const char *user,
+	const char *permission
+) {
+	db_for_all(closure, callback, client, session, user, permission);
+}
+
+int
+cyn_check_async(
+	void (*check_cb)(void *closure, uint32_t value),
+	void *closure,
+	const char *client,
+	const char *session,
+	const char *user,
+	const char *permission
+) {
+	uint32_t value;
+
+	cyn_test(client, session, user, permission, &value);
+	if (value == ALLOW || value == DENY) {
+		check_cb(closure, value);
+		return 0;
+	}
+
+	/* TODO: try to resolve AGENT?? */
+
+	check_cb(closure, value);
+	return 0;
+}
+