Add simple async wrappers around send, recv and connect

To be used later :-)
(This used to be commit 0d161d336ab9eeccd90d19ef1473646c3008864a)

1 files changed, 674 insertions, 0 deletions

diff --git a/source3/lib/async_sock.c b/source3/lib/async_sock.c
new file mode 100644
index 0000000000..1a4c27ba20
--- /dev/null
+++ b/source3/lib/async_sock.c
@@ -0,0 +1,674 @@
+/*
+   Unix SMB/CIFS implementation.
+   async socket syscalls
+   Copyright (C) Volker Lendecke 2008
+
+   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"
+
+/**
+ * Discriminator for async_syscall_state
+ */
+enum async_syscall_type {
+	ASYNC_SYSCALL_SEND,
+	ASYNC_SYSCALL_SENDALL,
+	ASYNC_SYSCALL_RECV,
+	ASYNC_SYSCALL_RECVALL,
+	ASYNC_SYSCALL_CONNECT
+};
+
+/**
+ * Holder for syscall arguments and the result
+ */
+
+struct async_syscall_state {
+	enum async_syscall_type syscall_type;
+	struct fd_event *fde;
+
+	union {
+		struct param_send {
+			int fd;
+			const void *buffer;
+			size_t length;
+			int flags;
+		} param_send;
+		struct param_sendall {
+			int fd;
+			const void *buffer;
+			size_t length;
+			int flags;
+			size_t sent;
+		} param_sendall;
+		struct param_recv {
+			int fd;
+			void *buffer;
+			size_t length;
+			int flags;
+		} param_recv;
+		struct param_recvall {
+			int fd;
+			void *buffer;
+			size_t length;
+			int flags;
+			size_t received;
+		} param_recvall;
+		struct param_connect {
+			/**
+			 * connect needs to be done on a nonblocking
+			 * socket. Keep the old flags around
+			 */
+			long old_sockflags;
+			int fd;
+			const struct sockaddr *address;
+			socklen_t address_len;
+		} param_connect;
+	} param;
+
+	union {
+		ssize_t result_ssize_t;
+		size_t result_size_t;
+		int result_int;
+	} result;
+	int sys_errno;
+};
+
+/**
+ * @brief Create a new async syscall req
+ * @param[in] mem_ctx	The memory context to hang the result off
+ * @param[in] ev	The event context to work from
+ * @param[in] type	Which syscall will this be
+ * @param[in] pstate	Where to put the newly created private_data state
+ * @retval The new request
+ *
+ * This is a helper function to prepare a new struct async_req with an
+ * associated struct async_syscall_state. The async_syscall_state will be put
+ * into the async_req as private_data.
+ */
+
+static struct async_req *async_syscall_new(TALLOC_CTX *mem_ctx,
+					   struct event_context *ev,
+					   enum async_syscall_type type,
+					   struct async_syscall_state **pstate)
+{
+	struct async_req *result;
+	struct async_syscall_state *state;
+
+	result = async_req_new(mem_ctx, ev);
+	if (result == NULL) {
+		return NULL;
+	}
+
+	state = talloc(result, struct async_syscall_state);
+	if (state == NULL) {
+		TALLOC_FREE(result);
+		return NULL;
+	}
+
+	state->syscall_type = type;
+
+	result->private_data = state;
+
+	*pstate = state;
+
+	return result;
+}
+
+/**
+ * @brief Create a new async syscall req based on a fd
+ * @param[in] mem_ctx	The memory context to hang the result off
+ * @param[in] ev	The event context to work from
+ * @param[in] type	Which syscall will this be
+ * @param[in] fd	The file descriptor we work on
+ * @param[in] fde_flags EVENT_FD_READ/WRITE -- what are we interested in?
+ * @param[in] fde_cb	The callback function for the file descriptor event
+ * @param[in] pstate	Where to put the newly created private_data state
+ * @retval The new request
+ *
+ * This is a helper function to prepare a new struct async_req with an
+ * associated struct async_syscall_state and an associated file descriptor
+ * event.
+ */
+
+static struct async_req *async_fde_syscall_new(
+	TALLOC_CTX *mem_ctx,
+	struct event_context *ev,
+	enum async_syscall_type type,
+	int fd,
+	uint16_t fde_flags,
+	void (*fde_cb)(struct event_context *ev,
+		       struct fd_event *fde, uint16_t flags,
+		       void *priv),
+	struct async_syscall_state **pstate)
+{
+	struct async_req *result;
+	struct async_syscall_state *state;
+
+	result = async_syscall_new(mem_ctx, ev, type, &state);
+	if (result == NULL) {
+		return NULL;
+	}
+
+	state->fde = event_add_fd(ev, state, fd, fde_flags, fde_cb, result);
+	if (state->fde == NULL) {
+		TALLOC_FREE(result);
+		return NULL;
+	}
+	*pstate = state;
+	return result;
+}
+
+/**
+ * Retrieve a ssize_t typed result from an async syscall
+ * @param[in] req	The syscall that has just finished
+ * @param[out] perrno	Where to put the syscall's errno
+ * @retval The return value from the asynchronously called syscall
+ */
+
+ssize_t async_syscall_result_ssize_t(struct async_req **req, int *perrno)
+{
+	struct async_syscall_state *state = talloc_get_type_abort(
+		(*req)->private_data, struct async_syscall_state);
+
+	int sys_errno = state->sys_errno;
+	ssize_t result = state->result.result_ssize_t;
+
+	TALLOC_FREE(*req);
+
+	*perrno = sys_errno;
+	return result;
+}
+
+/**
+ * Retrieve a size_t typed result from an async syscall
+ * @param[in] req	The syscall that has just finished
+ * @param[out] perrno	Where to put the syscall's errno
+ * @retval The return value from the asynchronously called syscall
+ */
+
+size_t async_syscall_result_size_t(struct async_req **req, int *perrno)
+{
+	struct async_syscall_state *state = talloc_get_type_abort(
+		(*req)->private_data, struct async_syscall_state);
+
+	int sys_errno = state->sys_errno;
+	size_t result = state->result.result_ssize_t;
+
+	TALLOC_FREE(*req);
+
+	*perrno = sys_errno;
+	return result;
+}
+
+/**
+ * Retrieve a int typed result from an async syscall
+ * @param[in] req	The syscall that has just finished
+ * @param[out] perrno	Where to put the syscall's errno
+ * @retval The return value from the asynchronously called syscall
+ */
+
+ssize_t async_syscall_result_int(struct async_req **req, int *perrno)
+{
+	struct async_syscall_state *state = talloc_get_type_abort(
+		(*req)->private_data, struct async_syscall_state);
+
+	int sys_errno = state->sys_errno;
+	int result = state->result.result_ssize_t;
+
+	TALLOC_FREE(*req);
+
+	*perrno = sys_errno;
+	return result;
+}
+
+/**
+ * fde event handler for the "send" syscall
+ * @param[in] ev	The event context that sent us here
+ * @param[in] fde	The file descriptor event associated with the send
+ * @param[in] flags	Can only be EVENT_FD_WRITE here
+ * @param[in] priv	private data, "struct async_req *" in this case
+ */
+
+static void async_send_callback(struct event_context *ev,
+				struct fd_event *fde, uint16_t flags,
+				void *priv)
+{
+	struct async_req *req = talloc_get_type_abort(
+		priv, struct async_req);
+	struct async_syscall_state *state = talloc_get_type_abort(
+		req->private_data, struct async_syscall_state);
+	struct param_send *p = &state->param.param_send;
+
+	SMB_ASSERT(state->syscall_type == ASYNC_SYSCALL_SEND);
+
+	state->result.result_ssize_t = send(p->fd, p->buffer, p->length,
+					    p->flags);
+	state->sys_errno = errno;
+
+	TALLOC_FREE(state->fde);
+
+	async_req_done(req);
+}
+
+/**
+ * Async version of send(2)
+ * @param[in] mem_ctx	The memory context to hang the result off
+ * @param[in] ev	The event context to work from
+ * @param[in] fd	The socket to send to
+ * @param[in] buffer	The buffer to send
+ * @param[in] length	How many bytes to send
+ * @param[in] flags	flags passed to send(2)
+ *
+ * This function is a direct counterpart of send(2)
+ */
+
+struct async_req *async_send(TALLOC_CTX *mem_ctx, struct event_context *ev,
+			     int fd, const void *buffer, size_t length,
+			     int flags)
+{
+	struct async_req *result;
+	struct async_syscall_state *state;
+
+	result = async_fde_syscall_new(
+		mem_ctx, ev, ASYNC_SYSCALL_SEND,
+		fd, EVENT_FD_WRITE, async_send_callback,
+		&state);
+	if (result == NULL) {
+		return NULL;
+	}
+
+	state->param.param_send.fd = fd;
+	state->param.param_send.buffer = buffer;
+	state->param.param_send.length = length;
+	state->param.param_send.flags = flags;
+
+	return result;
+}
+
+/**
+ * fde event handler for the "sendall" syscall group
+ * @param[in] ev	The event context that sent us here
+ * @param[in] fde	The file descriptor event associated with the send
+ * @param[in] flags	Can only be EVENT_FD_WRITE here
+ * @param[in] priv	private data, "struct async_req *" in this case
+ */
+
+static void async_sendall_callback(struct event_context *ev,
+				   struct fd_event *fde, uint16_t flags,
+				   void *priv)
+{
+	struct async_req *req = talloc_get_type_abort(
+		priv, struct async_req);
+	struct async_syscall_state *state = talloc_get_type_abort(
+		req->private_data, struct async_syscall_state);
+	struct param_sendall *p = &state->param.param_sendall;
+
+	SMB_ASSERT(state->syscall_type == ASYNC_SYSCALL_SENDALL);
+
+	state->result.result_ssize_t = send(p->fd, (char *)p->buffer + p->sent,
+					    p->length - p->sent, p->flags);
+	state->sys_errno = errno;
+
+	if (state->result.result_ssize_t == -1) {
+		async_req_error(req, map_nt_error_from_unix(state->sys_errno));
+		return;
+	}
+
+	if (state->result.result_ssize_t == 0) {
+		async_req_error(req, NT_STATUS_END_OF_FILE);
+		return;
+	}
+
+	p->sent += state->result.result_ssize_t;
+	SMB_ASSERT(p->sent <= p->length);
+
+	if (p->sent == p->length) {
+		TALLOC_FREE(state->fde);
+		async_req_done(req);
+	}
+}
+
+/**
+ * @brief Send all bytes to a socket
+ * @param[in] mem_ctx	The memory context to hang the result off
+ * @param[in] ev	The event context to work from
+ * @param[in] fd	The socket to send to
+ * @param[in] buffer	The buffer to send
+ * @param[in] length	How many bytes to send
+ * @param[in] flags	flags passed to send(2)
+ *
+ * async_sendall calls send(2) as long as it is necessary to send all of the
+ * "length" bytes
+ */
+
+struct async_req *async_sendall(TALLOC_CTX *mem_ctx, struct event_context *ev,
+				int fd, const void *buffer, size_t length,
+				int flags)
+{
+	struct async_req *result;
+	struct async_syscall_state *state;
+
+	result = async_fde_syscall_new(
+		mem_ctx, ev, ASYNC_SYSCALL_SENDALL,
+		fd, EVENT_FD_WRITE, async_sendall_callback,
+		&state);
+	if (result == NULL) {
+		return NULL;
+	}
+
+	state->param.param_sendall.fd = fd;
+	state->param.param_sendall.buffer = buffer;
+	state->param.param_sendall.length = length;
+	state->param.param_sendall.flags = flags;
+	state->param.param_sendall.sent = 0;
+
+	return result;
+}
+
+/**
+ * fde event handler for the "recv" syscall
+ * @param[in] ev	The event context that sent us here
+ * @param[in] fde	The file descriptor event associated with the recv
+ * @param[in] flags	Can only be EVENT_FD_READ here
+ * @param[in] priv	private data, "struct async_req *" in this case
+ */
+
+static void async_recv_callback(struct event_context *ev,
+				struct fd_event *fde, uint16_t flags,
+				void *priv)
+{
+	struct async_req *req = talloc_get_type_abort(
+		priv, struct async_req);
+	struct async_syscall_state *state = talloc_get_type_abort(
+		req->private_data, struct async_syscall_state);
+	struct param_recv *p = &state->param.param_recv;
+
+	SMB_ASSERT(state->syscall_type == ASYNC_SYSCALL_RECV);
+
+	state->result.result_ssize_t = recv(p->fd, p->buffer, p->length,
+					    p->flags);
+	state->sys_errno = errno;
+
+	TALLOC_FREE(state->fde);
+
+	async_req_done(req);
+}
+
+/**
+ * Async version of recv(2)
+ * @param[in] mem_ctx	The memory context to hang the result off
+ * @param[in] ev	The event context to work from
+ * @param[in] fd	The socket to recv from
+ * @param[in] buffer	The buffer to recv into
+ * @param[in] length	How many bytes to recv
+ * @param[in] flags	flags passed to recv(2)
+ *
+ * This function is a direct counterpart of recv(2)
+ */
+
+struct async_req *async_recv(TALLOC_CTX *mem_ctx, struct event_context *ev,
+			     int fd, void *buffer, size_t length,
+			     int flags)
+{
+	struct async_req *result;
+	struct async_syscall_state *state;
+
+	result = async_fde_syscall_new(
+		mem_ctx, ev, ASYNC_SYSCALL_RECV,
+		fd, EVENT_FD_READ, async_recv_callback,
+		&state);
+
+	if (result == NULL) {
+		return NULL;
+	}
+
+	state->param.param_recv.fd = fd;
+	state->param.param_recv.buffer = buffer;
+	state->param.param_recv.length = length;
+	state->param.param_recv.flags = flags;
+
+	return result;
+}
+
+/**
+ * fde event handler for the "recvall" syscall group
+ * @param[in] ev	The event context that sent us here
+ * @param[in] fde	The file descriptor event associated with the recv
+ * @param[in] flags	Can only be EVENT_FD_READ here
+ * @param[in] priv	private data, "struct async_req *" in this case
+ */
+
+static void async_recvall_callback(struct event_context *ev,
+				   struct fd_event *fde, uint16_t flags,
+				   void *priv)
+{
+	struct async_req *req = talloc_get_type_abort(
+		priv, struct async_req);
+	struct async_syscall_state *state = talloc_get_type_abort(
+		req->private_data, struct async_syscall_state);
+	struct param_recvall *p = &state->param.param_recvall;
+
+	SMB_ASSERT(state->syscall_type == ASYNC_SYSCALL_RECVALL);
+
+	state->result.result_ssize_t = recv(p->fd,
+					    (char *)p->buffer + p->received,
+					    p->length - p->received, p->flags);
+	state->sys_errno = errno;
+
+	if (state->result.result_ssize_t == -1) {
+		async_req_error(req, map_nt_error_from_unix(state->sys_errno));
+		return;
+	}
+
+	if (state->result.result_ssize_t == 0) {
+		async_req_error(req, NT_STATUS_END_OF_FILE);
+		return;
+	}
+
+	p->received += state->result.result_ssize_t;
+	SMB_ASSERT(p->received <= p->length);
+
+	if (p->received == p->length) {
+		TALLOC_FREE(state->fde);
+		async_req_done(req);
+	}
+}
+
+/**
+ * Receive a specified number of bytes from a socket
+ * @param[in] mem_ctx	The memory context to hang the result off
+ * @param[in] ev	The event context to work from
+ * @param[in] fd	The socket to recv from
+ * @param[in] buffer	The buffer to recv into
+ * @param[in] length	How many bytes to recv
+ * @param[in] flags	flags passed to recv(2)
+ *
+ * async_recvall will call recv(2) until "length" bytes are received
+ */
+
+struct async_req *async_recvall(TALLOC_CTX *mem_ctx, struct event_context *ev,
+				int fd, void *buffer, size_t length,
+				int flags)
+{
+	struct async_req *result;
+	struct async_syscall_state *state;
+
+	result = async_fde_syscall_new(
+		mem_ctx, ev, ASYNC_SYSCALL_RECVALL,
+		fd, EVENT_FD_READ, async_recvall_callback,
+		&state);
+	if (result == NULL) {
+		return NULL;
+	}
+
+	state->param.param_recvall.fd = fd;
+	state->param.param_recvall.buffer = buffer;
+	state->param.param_recvall.length = length;
+	state->param.param_recvall.flags = flags;
+	state->param.param_recvall.received = 0;
+
+	return result;
+}
+
+/**
+ * fde event handler for connect(2)
+ * @param[in] ev	The event context that sent us here
+ * @param[in] fde	The file descriptor event associated with the connect
+ * @param[in] flags	Indicate read/writeability of the socket
+ * @param[in] priv	private data, "struct async_req *" in this case
+ */
+
+static void async_connect_callback(struct event_context *ev,
+				   struct fd_event *fde, uint16_t flags,
+				   void *priv)
+{
+	struct async_req *req = talloc_get_type_abort(
+		priv, struct async_req);
+	struct async_syscall_state *state = talloc_get_type_abort(
+		req->private_data, struct async_syscall_state);
+	struct param_connect *p = &state->param.param_connect;
+
+	SMB_ASSERT(state->syscall_type == ASYNC_SYSCALL_CONNECT);
+
+	TALLOC_FREE(state->fde);
+
+	/*
+	 * Stevens, Network Programming says that if there's a
+	 * successful connect, the socket is only writable. Upon an
+	 * error, it's both readable and writable.
+	 */
+	if ((flags & (EVENT_FD_READ|EVENT_FD_WRITE))
+	    == (EVENT_FD_READ|EVENT_FD_WRITE)) {
+		int sockerr;
+		socklen_t err_len = sizeof(sockerr);
+
+		if (getsockopt(p->fd, SOL_SOCKET, SO_ERROR,
+			       (void *)&sockerr, &err_len) == 0) {
+			errno = sockerr;
+		}
+
+		state->sys_errno = errno;
+
+		DEBUG(10, ("connect returned %s\n", strerror(errno)));
+
+		sys_fcntl_long(p->fd, F_SETFL, p->old_sockflags);
+
+		async_req_error(req, map_nt_error_from_unix(state->sys_errno));
+		return;
+	}
+
+	sys_fcntl_long(p->fd, F_SETFL, p->old_sockflags);
+
+	state->result.result_int = 0;
+	state->sys_errno = 0;
+
+	async_req_done(req);
+}
+
+/**
+ * @brief async version of connect(2)
+ * @param[in] mem_ctx	The memory context to hang the result off
+ * @param[in] ev	The event context to work from
+ * @param[in] fd	The socket to recv from
+ * @param[in] address	Where to connect?
+ * @param[in] address_len Length of *address
+ * @retval The async request
+ *
+ * This function sets the socket into non-blocking state to be able to call
+ * connect in an async state. This will be reset when the request is finished.
+ */
+
+struct async_req *async_connect(TALLOC_CTX *mem_ctx, struct event_context *ev,
+				int fd, const struct sockaddr *address,
+				socklen_t address_len)
+{
+	struct async_req *result;
+	struct async_syscall_state *state;
+	struct param_connect *p;
+
+	result = async_syscall_new(mem_ctx, ev, ASYNC_SYSCALL_CONNECT, &state);
+	if (result == NULL) {
+		return NULL;
+	}
+	p = &state->param.param_connect;
+
+	/**
+	 * We have to set the socket to nonblocking for async connect(2). Keep
+	 * the old sockflags around.
+	 */
+
+	p->old_sockflags = sys_fcntl_long(fd, F_GETFL, 0);
+
+	if (p->old_sockflags == -1) {
+		if (async_post_status(result, map_nt_error_from_unix(errno))) {
+			return result;
+		}
+		TALLOC_FREE(result);
+		return NULL;
+	}
+
+	set_blocking(fd, true);
+
+	state->result.result_int = connect(fd, address, address_len);
+
+	if (state->result.result_int == 0) {
+		state->sys_errno = 0;
+		if (async_post_status(result, NT_STATUS_OK)) {
+			return result;
+		}
+		sys_fcntl_long(fd, F_SETFL, p->old_sockflags);
+		TALLOC_FREE(result);
+		return NULL;
+	}
+
+	/**
+	 * A number of error messages show that something good is progressing
+	 * and that we have to wait for readability.
+	 *
+	 * If none of them are present, bail out.
+	 */
+
+	if (!(errno == EINPROGRESS || errno == EALREADY ||
+#ifdef EISCONN
+	      errno == EISCONN ||
+#endif
+	      errno == EAGAIN || errno == EINTR)) {
+
+		state->sys_errno = errno;
+
+		if (async_post_status(result, map_nt_error_from_unix(errno))) {
+			return result;
+		}
+		sys_fcntl_long(fd, F_SETFL, p->old_sockflags);
+		TALLOC_FREE(result);
+		return NULL;
+	}
+
+	state->fde = event_add_fd(ev, state, fd,
+				  EVENT_FD_READ | EVENT_FD_WRITE,
+				  async_connect_callback, state);
+	if (state->fde == NULL) {
+		sys_fcntl_long(fd, F_SETFL, p->old_sockflags);
+		TALLOC_FREE(result);
+		return NULL;
+	}
+
+	state->param.param_connect.fd = fd;
+	state->param.param_connect.address = address;
+	state->param.param_connect.address_len = address_len;
+
+	return result;
+}
+