Add fncall_send/recv

1 files changed, 365 insertions, 0 deletions

diff --git a/source3/lib/fncall.c b/source3/lib/fncall.c
new file mode 100644
index 0000000000..e810b6814e
--- /dev/null
+++ b/source3/lib/fncall.c
@@ -0,0 +1,365 @@
+/*
+ * Unix SMB/CIFS implementation.
+ * Async fn calls
+ * Copyright (C) Volker Lendecke 2009
+ *
+ * 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 <http://www.gnu.org/licenses/>.
+ */
+
+#include "includes.h"
+
+#if WITH_PTHREADPOOL
+
+#include "pthreadpool.h"
+
+struct fncall_state {
+	struct fncall_context *ctx;
+	int job_id;
+	bool done;
+
+	void *private_parent;
+	void *job_private;
+};
+
+struct fncall_context {
+	struct pthreadpool *pool;
+	int next_job_id;
+	int sig_fd;
+	struct tevent_req **pending;
+
+	struct fncall_state **orphaned;
+	int num_orphaned;
+
+	struct fd_event *fde;
+};
+
+static void fncall_handler(struct tevent_context *ev, struct tevent_fd *fde,
+			   uint16_t flags, void *private_data);
+
+static int fncall_context_destructor(struct fncall_context *ctx)
+{
+	while (talloc_array_length(ctx->pending) != 0) {
+		/* No TALLOC_FREE here */
+		talloc_free(ctx->pending[0]);
+	}
+
+	while (ctx->num_orphaned != 0) {
+		/*
+		 * We've got jobs in the queue for which the tevent_req has
+		 * been finished already. Wait for all of them to finish.
+		 */
+		fncall_handler(NULL, NULL, TEVENT_FD_READ, ctx);
+	}
+
+	pthreadpool_destroy(ctx->pool);
+	ctx->pool = NULL;
+
+	return 0;
+}
+
+struct fncall_context *fncall_context_init(TALLOC_CTX *mem_ctx,
+					   int max_threads)
+{
+	struct fncall_context *ctx;
+	int ret;
+
+	ctx = talloc_zero(mem_ctx, struct fncall_context);
+	if (ctx == NULL) {
+		return NULL;
+	}
+
+	ret = pthreadpool_init(max_threads, &ctx->pool);
+	if (ret != 0) {
+		TALLOC_FREE(ctx);
+		return NULL;
+	}
+	talloc_set_destructor(ctx, fncall_context_destructor);
+
+	ctx->sig_fd = pthreadpool_sig_fd(ctx->pool);
+	if (ctx->sig_fd == -1) {
+		TALLOC_FREE(ctx);
+		return NULL;
+	}
+
+	return ctx;
+}
+
+static int fncall_next_job_id(struct fncall_context *ctx)
+{
+	int num_pending = talloc_array_length(ctx->pending);
+	int result;
+
+	while (true) {
+		int i;
+
+		result = ctx->next_job_id++;
+		if (result == 0) {
+			continue;
+		}
+
+		for (i=0; i<num_pending; i++) {
+			struct fncall_state *state = tevent_req_data(
+				ctx->pending[i], struct fncall_state);
+
+			if (result == state->job_id) {
+				break;
+			}
+		}
+		if (i == num_pending) {
+			return result;
+		}
+	}
+}
+
+static void fncall_unset_pending(struct tevent_req *req);
+static int fncall_destructor(struct tevent_req *req);
+
+static bool fncall_set_pending(struct tevent_req *req,
+			       struct fncall_context *ctx,
+			       struct tevent_context *ev)
+{
+	struct tevent_req **pending;
+	int num_pending, orphaned_array_length;
+
+	num_pending = talloc_array_length(ctx->pending);
+
+	pending = talloc_realloc(ctx, ctx->pending, struct tevent_req *,
+				 num_pending+1);
+	if (pending == NULL) {
+		return false;
+	}
+	pending[num_pending] = req;
+	num_pending += 1;
+	ctx->pending = pending;
+	talloc_set_destructor(req, fncall_destructor);
+
+	/*
+	 * Make sure that the orphaned array of fncall_state structs has
+	 * enough space. A job can change from pending to orphaned in
+	 * fncall_destructor, and to fail in a talloc destructor should be
+	 * avoided if possible.
+	 */
+
+	orphaned_array_length = talloc_array_length(ctx->orphaned);
+	if (num_pending > orphaned_array_length) {
+		struct fncall_state **orphaned;
+
+		orphaned = talloc_realloc(ctx, ctx->orphaned,
+					  struct fncall_state *,
+					  orphaned_array_length + 1);
+		if (orphaned == NULL) {
+			fncall_unset_pending(req);
+			return false;
+		}
+		ctx->orphaned = orphaned;
+	}
+
+	if (ctx->fde != NULL) {
+		return true;
+	}
+
+	ctx->fde = tevent_add_fd(ev, ctx->pending, ctx->sig_fd, TEVENT_FD_READ,
+				 fncall_handler, ctx);
+	if (ctx->fde == NULL) {
+		fncall_unset_pending(req);
+		return false;
+	}
+	return true;
+}
+
+static void fncall_unset_pending(struct tevent_req *req)
+{
+	struct fncall_state *state = tevent_req_data(req, struct fncall_state);
+	struct fncall_context *ctx = state->ctx;
+	int num_pending = talloc_array_length(ctx->pending);
+	int i;
+
+	if (num_pending == 1) {
+		TALLOC_FREE(ctx->fde);
+		TALLOC_FREE(ctx->pending);
+		return;
+	}
+
+	for (i=0; i<num_pending; i++) {
+		if (req == ctx->pending[i]) {
+			break;
+		}
+	}
+	if (i == num_pending) {
+		return;
+	}
+	if (num_pending > 1) {
+		ctx->pending[i] = ctx->pending[num_pending-1];
+	}
+	ctx->pending = talloc_realloc(NULL, ctx->pending, struct tevent_req *,
+				      num_pending - 1);
+}
+
+static int fncall_destructor(struct tevent_req *req)
+{
+	struct fncall_state *state = tevent_req_data(
+		req, struct fncall_state);
+	struct fncall_context *ctx = state->ctx;
+
+	fncall_unset_pending(req);
+
+	if (state->done) {
+		return 0;
+	}
+
+	/*
+	 * Keep around the state of the deleted request until the request has
+	 * finished in the helper thread. fncall_handler will destroy it.
+	 */
+	ctx->orphaned[ctx->num_orphaned] = talloc_move(ctx->orphaned, &state);
+	ctx->num_orphaned += 1;
+
+	return 0;
+}
+
+struct tevent_req *fncall_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
+			       struct fncall_context *ctx,
+			       void (*fn)(void *private_data),
+			       void *private_data)
+{
+	struct tevent_req *req;
+	struct fncall_state *state;
+	int ret;
+
+	req = tevent_req_create(mem_ctx, &state, struct fncall_state);
+	if (req == NULL) {
+		return NULL;
+	}
+	state->ctx = ctx;
+	state->job_id = fncall_next_job_id(state->ctx);
+	state->done = false;
+
+	/*
+	 * We need to keep the private data we handed out to the thread around
+	 * as long as the job is not finished. This is a bit of an abstraction
+	 * violation, because the "req->state1->subreq->state2" (we're
+	 * "subreq", "req" is the request our caller creates) is broken to
+	 * "ctx->state2->state1", but we are right now in the destructor for
+	 * "subreq2", so what can we do. We need to keep state1 around,
+	 * otherwise the helper thread will have no place to put its results.
+	 */
+
+	state->private_parent = talloc_parent(private_data);
+	state->job_private = talloc_move(state, &private_data);
+
+	ret = pthreadpool_add_job(state->ctx->pool, state->job_id, fn,
+				  state->job_private);
+	if (ret == -1) {
+		tevent_req_error(req, errno);
+		return tevent_req_post(req, ev);
+	}
+	if (!fncall_set_pending(req, state->ctx, ev)) {
+		tevent_req_nomem(NULL, req);
+		return tevent_req_post(req, ev);
+	}
+	return req;
+}
+
+static void fncall_handler(struct tevent_context *ev, struct tevent_fd *fde,
+			   uint16_t flags, void *private_data)
+{
+	struct fncall_context *ctx = talloc_get_type_abort(
+		private_data, struct fncall_context);
+	int i, num_pending;
+	int job_id;
+
+	job_id = pthreadpool_finished_job(ctx->pool);
+	if (job_id <= 0) {
+		return;
+	}
+
+	num_pending = talloc_array_length(ctx->pending);
+
+	for (i=0; i<num_pending; i++) {
+		struct fncall_state *state = tevent_req_data(
+			ctx->pending[i], struct fncall_state);
+
+		if (job_id == state->job_id) {
+			state->done = true;
+			talloc_move(state->private_parent,
+				    &state->job_private);
+			tevent_req_done(ctx->pending[i]);
+			return;
+		}
+	}
+
+	for (i=0; i<ctx->num_orphaned; i++) {
+		if (job_id == ctx->orphaned[i]->job_id) {
+			break;
+		}
+	}
+	if (i == ctx->num_orphaned) {
+		return;
+	}
+
+	TALLOC_FREE(ctx->orphaned[i]);
+
+	if (i < ctx->num_orphaned-1) {
+		ctx->orphaned[i] = ctx->orphaned[ctx->num_orphaned-1];
+	}
+	ctx->num_orphaned -= 1;
+}
+
+int fncall_recv(struct tevent_req *req, int *perr)
+{
+	if (tevent_req_is_unix_error(req, perr)) {
+		return -1;
+	}
+	return 0;
+}
+
+#else  /* WITH_PTHREADPOOL */
+
+struct fncall_context {
+	uint8_t dummy;
+};
+
+struct fncall_context *fncall_context_init(TALLOC_CTX *mem_ctx,
+					   int max_threads)
+{
+	return talloc(mem_ctx, struct fncall_context);
+}
+
+struct fncall_state {
+	uint8_t dummy;
+};
+
+struct tevent_req *fncall_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
+			       struct fncall_context *ctx,
+			       void (*fn)(void *private_data),
+			       void *private_data)
+{
+	struct tevent_req *req;
+	struct fncall_state *state;
+
+	req = tevent_req_create(mem_ctx, &state, struct fncall_state);
+	if (req == NULL) {
+		return NULL;
+	}
+	fn(private_data);
+	tevent_req_post(req, ev);
+	return req;
+}
+
+int fncall_recv(struct tevent_req *req, int *perr)
+{
+	return 0;
+}
+
+#endif