lib/tsocket: add tsocket_readv_send/recv()

metze

3 files changed, 235 insertions, 1 deletions

diff --git a/lib/tsocket/config.mk b/lib/tsocket/config.mk
index 72614a3f82..c35f0afd6f 100644
--- a/lib/tsocket/config.mk
+++ b/lib/tsocket/config.mk
@@ -8,7 +8,8 @@ LIBTSOCKET_OBJ_FILES = $(addprefix ../lib/tsocket/, \
 					tsocket_recvfrom.o \
 					tsocket_sendto.o \
 					tsocket_connect.o \
-					tsocket_writev.o)
+					tsocket_writev.o \
+					tsocket_readv.o)
 
 PUBLIC_HEADERS += $(addprefix ../lib/tsocket/, \
 				 tsocket.h\
diff --git a/lib/tsocket/tsocket.h b/lib/tsocket/tsocket.h
index d4fb68f766..9bcfb5cb7e 100644
--- a/lib/tsocket/tsocket.h
+++ b/lib/tsocket/tsocket.h
@@ -205,5 +205,16 @@ struct tevent_req *tsocket_writev_queue_send(TALLOC_CTX *mem_ctx,
 					     size_t count);
 int tsocket_writev_queue_recv(struct tevent_req *req, int *perrno);
 
+typedef int (*tsocket_readv_next_iovec_t)(struct tsocket_context *sock,
+					  void *private_data,
+					  TALLOC_CTX *mem_ctx,
+					  struct iovec **vector,
+					  size_t *count);
+struct tevent_req *tsocket_readv_send(struct tsocket_context *sock,
+				      TALLOC_CTX *mem_ctx,
+				      tsocket_readv_next_iovec_t next_iovec_fn,
+				      void *private_data);
+int tsocket_readv_recv(struct tevent_req *req, int *perrno);
+
 #endif /* _TSOCKET_H */
 
diff --git a/lib/tsocket/tsocket_readv.c b/lib/tsocket/tsocket_readv.c
new file mode 100644
index 0000000000..2c8483ec7e
--- /dev/null
+++ b/lib/tsocket/tsocket_readv.c
@@ -0,0 +1,222 @@
+/*
+   Unix SMB/CIFS implementation.
+
+   Copyright (C) Stefan Metzmacher 2009
+
+     ** NOTE! The following LGPL license applies to the tevent
+     ** library. This does NOT imply that all of Samba is released
+     ** under the LGPL
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with this library; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "replace.h"
+#include "system/network.h"
+#include "tsocket.h"
+#include "tsocket_internal.h"
+
+struct tsocket_readv_state {
+	/* this structs are owned by the caller */
+	struct {
+		struct tsocket_context *sock;
+		tsocket_readv_next_iovec_t next_iovec_fn;
+		void *private_data;
+	} caller;
+
+	/*
+	 * Each call to the callback resets iov and count
+	 * the callback allocated the iov as child of our state,
+	 * that means we are allowed to modify and free it.
+	 *
+	 * we should call the callback every time we filled the given
+	 * vector and ask for a new vector. We return if the callback
+	 * ask for 0 bytes.
+	 */
+	struct iovec *iov;
+	size_t count;
+
+	/*
+	 * the total number of bytes we read,
+	 * the return value of the _recv function
+	 */
+	int total_read;
+};
+
+static int tsocket_readv_state_destructor(struct tsocket_readv_state *state)
+{
+	if (state->caller.sock) {
+		tsocket_set_readable_handler(state->caller.sock, NULL, NULL);
+	}
+	ZERO_STRUCT(state->caller);
+
+	return 0;
+}
+
+static bool tsocket_readv_ask_for_next_vector(struct tevent_req *req,
+					      struct tsocket_readv_state *state)
+{
+	int ret;
+	int err;
+	bool dummy;
+	size_t to_read = 0;
+	size_t i;
+
+	talloc_free(state->iov);
+	state->iov = NULL;
+	state->count = 0;
+
+	ret = state->caller.next_iovec_fn(state->caller.sock,
+					  state->caller.private_data,
+					  state, &state->iov, &state->count);
+	err = tsocket_error_from_errno(ret, errno, &dummy);
+	if (tevent_req_error(req, err)) {
+		return false;
+	}
+
+	for (i=0; i < state->count; i++) {
+		size_t tmp = to_read;
+		tmp += state->iov[i].iov_len;
+
+		if (tmp < to_read) {
+			tevent_req_error(req, EMSGSIZE);
+			return false;
+		}
+
+		to_read = tmp;
+	}
+
+	if (to_read == 0) {
+		tevent_req_done(req);
+		return false;
+	}
+
+	if (state->total_read + to_read < state->total_read) {
+		tevent_req_error(req, EMSGSIZE);
+		return false;
+	}
+
+	return true;
+}
+
+static void tsocket_readv_handler(struct tsocket_context *sock,
+				  void *private_data);
+
+struct tevent_req *tsocket_readv_send(struct tsocket_context *sock,
+				      TALLOC_CTX *mem_ctx,
+				      tsocket_readv_next_iovec_t next_iovec_fn,
+				      void *private_data)
+{
+	struct tevent_req *req;
+	struct tsocket_readv_state *state;
+	int ret;
+	int err;
+	bool dummy;
+
+	req = tevent_req_create(mem_ctx, &state,
+				struct tsocket_readv_state);
+	if (!req) {
+		return NULL;
+	}
+
+	state->caller.sock		= sock;
+	state->caller.next_iovec_fn	= next_iovec_fn;
+	state->caller.private_data	= private_data;
+
+	state->iov		= NULL;
+	state->count		= 0;
+	state->total_read	= 0;
+
+	if (!tsocket_readv_ask_for_next_vector(req, state)) {
+		goto post;
+	}
+
+	talloc_set_destructor(state, tsocket_readv_state_destructor);
+
+	ret = tsocket_set_readable_handler(sock,
+					   tsocket_readv_handler,
+					   req);
+	err = tsocket_error_from_errno(ret, errno, &dummy);
+	if (tevent_req_error(req, err)) {
+		goto post;
+	}
+
+	return req;
+
+ post:
+	return tevent_req_post(req, sock->event.ctx);
+}
+
+static void tsocket_readv_handler(struct tsocket_context *sock,
+				  void *private_data)
+{
+	struct tevent_req *req = talloc_get_type(private_data,
+				 struct tevent_req);
+	struct tsocket_readv_state *state = tevent_req_data(req,
+					    struct tsocket_readv_state);
+	ssize_t ret;
+	int err;
+	bool retry;
+
+	ret = tsocket_readv(state->caller.sock,
+			    state->iov,
+			    state->count);
+	err = tsocket_error_from_errno(ret, errno, &retry);
+	if (retry) {
+		/* retry later */
+		return;
+	}
+	if (tevent_req_error(req, err)) {
+		return;
+	}
+
+	state->total_read += ret;
+
+	while (ret > 0) {
+		if (ret < state->iov[0].iov_len) {
+			uint8_t *base;
+			base = (uint8_t *)state->iov[0].iov_base;
+			base += ret;
+			state->iov[0].iov_base = base;
+			state->iov[0].iov_len -= ret;
+			break;
+		}
+		ret -= state->iov[0].iov_len;
+		state->iov += 1;
+		state->count -= 1;
+	}
+
+	if (state->count) {
+		/* we have more to read */
+		return;
+	}
+
+	/* ask the callback for a new vector we should fill */
+	tsocket_readv_ask_for_next_vector(req, state);
+}
+
+int tsocket_readv_recv(struct tevent_req *req, int *perrno)
+{
+	struct tsocket_readv_state *state = tevent_req_data(req,
+					    struct tsocket_readv_state);
+	int ret;
+
+	ret = tsocket_simple_int_recv(req, perrno);
+	if (ret == 0) {
+		ret = state->total_read;
+	}
+
+	tevent_req_received(req);
+	return ret;
+}
+