s3-prefork: add asynchronous functions

To get a client connection it is now possible to use asynchronous functions.

Signed-off-by: Andreas Schneider <asn@samba.org>

2 files changed, 267 insertions, 1 deletions

diff --git a/source3/lib/server_prefork.c b/source3/lib/server_prefork.c
index 4aa3f482cc..b337fa0c3b 100644
--- a/source3/lib/server_prefork.c
+++ b/source3/lib/server_prefork.c
@@ -24,6 +24,7 @@
 #include "system/filesys.h"
 #include "server_prefork.h"
 #include "../lib/util/util.h"
+#include "../lib/util/tevent_unix.h"
 
 struct prefork_pool {
 
@@ -94,7 +95,6 @@ bool prefork_create_pool(struct tevent_context *ev_ctx,
 		case 0: /* THE CHILD */
 
 			pfp->pool[i].status = PF_WORKER_IDLE;
-
 			ret = pfp->main_fn(ev_ctx, &pfp->pool[i],
 					   pfp->listen_fd, pfp->lock_fd,
 					   pfp->private_data);
@@ -500,3 +500,261 @@ int prefork_wait_for_client(struct pf_worker_data *pf,
 	*fd = sd;
 	return 0;
 }
+
+/* ==== async code ==== */
+
+#define PF_ASYNC_LOCK_GRAB	0x01
+#define PF_ASYNC_LOCK_RELEASE	0x02
+#define PF_ASYNC_ACTION_MASK	0x03
+#define PF_ASYNC_LOCK_DONE	0x04
+
+struct pf_lock_state {
+	struct pf_worker_data *pf;
+	int lock_fd;
+	int flags;
+};
+
+static void prefork_lock_handler(struct tevent_context *ev,
+					struct tevent_timer *te,
+					struct timeval curtime, void *pvt);
+
+static struct tevent_req *prefork_lock_send(TALLOC_CTX *mem_ctx,
+						struct tevent_context *ev,
+						struct pf_worker_data *pf,
+						int lock_fd, int action)
+{
+	struct tevent_req *req;
+	struct pf_lock_state *state;
+
+	req = tevent_req_create(mem_ctx, &state, struct pf_lock_state);
+	if (!req) {
+		return NULL;
+	}
+
+	state->pf = pf;
+	state->lock_fd = lock_fd;
+	state->flags = action;
+
+	/* try once immediately */
+	prefork_lock_handler(ev, NULL, tevent_timeval_zero(), req);
+	if (state->flags & PF_ASYNC_LOCK_DONE) {
+		tevent_req_post(req, ev);
+	}
+
+	return req;
+}
+
+static void prefork_lock_handler(struct tevent_context *ev,
+				 struct tevent_timer *te,
+				 struct timeval curtime, void *pvt)
+{
+	struct tevent_req *req;
+	struct pf_lock_state *state;
+	int ret;
+
+	req = talloc_get_type_abort(pvt, struct tevent_req);
+	state = tevent_req_data(req, struct pf_lock_state);
+
+	switch (state->flags & PF_ASYNC_ACTION_MASK) {
+	case PF_ASYNC_LOCK_GRAB:
+		ret = prefork_grab_lock(state->pf, state->lock_fd, 0);
+		break;
+	case PF_ASYNC_LOCK_RELEASE:
+		ret = prefork_release_lock(state->pf, state->lock_fd, 0);
+		break;
+	default:
+		ret = EINVAL;
+		break;
+	}
+
+	switch (ret) {
+	case 0:
+		state->flags |= PF_ASYNC_LOCK_DONE;
+		tevent_req_done(req);
+		return;
+	case -1:
+		te = tevent_add_timer(ev, state,
+					tevent_timeval_current_ofs(1, 0),
+					prefork_lock_handler, req);
+		tevent_req_nomem(te, req);
+		return;
+	case -2:
+		/* server tells us to stop */
+		state->flags |= PF_ASYNC_LOCK_DONE;
+		tevent_req_error(req, -2);
+		return;
+	default:
+		state->flags |= PF_ASYNC_LOCK_DONE;
+		tevent_req_error(req, ret);
+		return;
+	}
+}
+
+static int prefork_lock_recv(struct tevent_req *req)
+{
+	int ret;
+
+	if (!tevent_req_is_unix_error(req, &ret)) {
+		ret = 0;
+	}
+
+	tevent_req_received(req);
+	return ret;
+}
+
+struct pf_listen_state {
+	struct tevent_context *ev;
+	struct pf_worker_data *pf;
+
+	int lock_fd;
+	int listen_fd;
+
+	struct sockaddr *addr;
+	socklen_t *addrlen;
+
+	int accept_fd;
+
+	int error;
+};
+
+static void prefork_listen_lock_done(struct tevent_req *subreq);
+static void prefork_listen_accept_handler(struct tevent_context *ev,
+					  struct tevent_fd *fde,
+					  uint16_t flags, void *pvt);
+static void prefork_listen_release_done(struct tevent_req *subreq);
+
+struct tevent_req *prefork_listen_send(TALLOC_CTX *mem_ctx,
+					struct tevent_context *ev,
+					struct pf_worker_data *pf,
+					int lock_fd, int listen_fd,
+					struct sockaddr *addr,
+					socklen_t *addrlen)
+{
+	struct tevent_req *req, *subreq;
+	struct pf_listen_state *state;
+
+	req = tevent_req_create(mem_ctx, &state, struct pf_listen_state);
+	if (!req) {
+		return NULL;
+	}
+
+	state->ev = ev;
+	state->pf = pf;
+	state->lock_fd = lock_fd;
+	state->listen_fd = listen_fd;
+	state->addr = addr;
+	state->addrlen = addrlen;
+	state->accept_fd = -1;
+	state->error = 0;
+
+	subreq = prefork_lock_send(state, state->ev, state->pf,
+				   state->lock_fd, PF_ASYNC_LOCK_GRAB);
+	if (tevent_req_nomem(subreq, req)) {
+		return tevent_req_post(req, ev);
+	}
+
+	tevent_req_set_callback(subreq, prefork_listen_lock_done, req);
+	return req;
+}
+
+static void prefork_listen_lock_done(struct tevent_req *subreq)
+{
+	struct tevent_req *req;
+	struct pf_listen_state *state;
+	struct tevent_fd *fde;
+	int ret;
+
+	req = tevent_req_callback_data(subreq, struct tevent_req);
+	state = tevent_req_data(req, struct pf_listen_state);
+
+	ret = prefork_lock_recv(subreq);
+	if (ret != 0) {
+		tevent_req_error(req, ret);
+		return;
+	}
+
+	/* next step, accept */
+	fde = tevent_add_fd(state->ev, state,
+			    state->listen_fd, TEVENT_FD_READ,
+			    prefork_listen_accept_handler, req);
+	tevent_req_nomem(fde, req);
+}
+
+static void prefork_listen_accept_handler(struct tevent_context *ev,
+					  struct tevent_fd *fde,
+					  uint16_t flags, void *pvt)
+{
+	struct pf_listen_state *state;
+	struct tevent_req *req, *subreq;
+	int err = 0;
+	int sd = -1;
+
+	req = talloc_get_type_abort(pvt, struct tevent_req);
+	state = tevent_req_data(req, struct pf_listen_state);
+
+	sd = accept(state->listen_fd, state->addr, state->addrlen);
+	if (sd == -1) {
+		if (errno == EINTR) {
+			/* keep trying */
+			return;
+		}
+		err = errno;
+		DEBUG(6, ("Accept failed! (%d, %s)\n", err, strerror(err)));
+
+	}
+
+	/* do not track the listen fd anymore */
+	talloc_free(fde);
+	if (err) {
+		tevent_req_error(req, err);
+		return;
+	}
+
+	state->accept_fd = sd;
+
+	/* release lock now */
+	subreq = prefork_lock_send(state, state->ev, state->pf,
+				   state->lock_fd, PF_ASYNC_LOCK_RELEASE);
+	if (tevent_req_nomem(subreq, req)) {
+		return;
+	}
+	tevent_req_set_callback(subreq, prefork_listen_release_done, req);
+}
+
+static void prefork_listen_release_done(struct tevent_req *subreq)
+{
+	struct tevent_req *req;
+	int ret;
+
+	req = tevent_req_callback_data(subreq, struct tevent_req);
+
+	ret = prefork_lock_recv(subreq);
+	if (ret != 0) {
+		tevent_req_error(req, ret);
+		return;
+	}
+
+	tevent_req_done(req);
+}
+
+int prefork_listen_recv(struct tevent_req *req, int *fd)
+{
+	struct pf_listen_state *state;
+	int ret;
+
+	state = tevent_req_data(req, struct pf_listen_state);
+
+	if (tevent_req_is_unix_error(req, &ret)) {
+		if (state->accept_fd != -1) {
+			close(state->accept_fd);
+		}
+	} else {
+		*fd = state->accept_fd;
+		ret = 0;
+		state->pf->status = PF_WORKER_BUSY;
+		state->pf->num_clients++;
+	}
+
+	tevent_req_received(req);
+	return ret;
+}
diff --git a/source3/lib/server_prefork.h b/source3/lib/server_prefork.h
index d6d7bf95c9..7e95602e81 100644
--- a/source3/lib/server_prefork.h
+++ b/source3/lib/server_prefork.h
@@ -74,3 +74,11 @@ int prefork_wait_for_client(struct pf_worker_data *pf,
 			    int lock_fd, int listen_fd,
 			    struct sockaddr *addr,
 			    socklen_t *addrlen, int *fd);
+
+struct tevent_req *prefork_listen_send(TALLOC_CTX *mem_ctx,
+					struct tevent_context *ev,
+					struct pf_worker_data *pf,
+					int lock_fd, int listen_fd,
+					struct sockaddr *addr,
+					socklen_t *addrlen);
+int prefork_listen_recv(struct tevent_req *req, int *fd);