- Extend the nsswitch to support Services, Protocols and Rpc

  databases.
- Make nsswitch support caching.

Submitted by:	Michael Bushkov <bushman__at__rsu.ru>
Sponsored by:	Google Summer of Code 2005

1 files changed, 576 insertions, 0 deletions

diff --git a/lib/libc/net/nscachedcli.c b/lib/libc/net/nscachedcli.c
new file mode 100644
index 0000000..374f370
--- /dev/null
+++ b/lib/libc/net/nscachedcli.c
@@ -0,0 +1,576 @@
+/*-
+ * Copyright (c) 2005 Michael Bushkov <bushman@rsu.ru>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include "namespace.h"
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/event.h>
+#include <sys/uio.h>
+#include <sys/un.h>
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include "un-namespace.h"
+#include "nscachedcli.h"
+
+#define NS_DEFAULT_CACHED_IO_TIMEOUT	4
+
+static int safe_write(struct cached_connection_ *, const void *, size_t);
+static int safe_read(struct cached_connection_ *, void *, size_t);
+static int send_credentials(struct cached_connection_ *, int);
+
+/*
+ * safe_write writes data to the specified connection and tries to do it in
+ * the very safe manner. We ensure, that we can write to the socket with
+ * kevent. If the data_size can't be sent in one piece, then it would be
+ * splitted.
+ */
+static int
+safe_write(struct cached_connection_ *connection, const void *data,
+    size_t data_size)
+{
+	struct kevent eventlist;
+	int nevents;
+	size_t result;
+	ssize_t s_result;
+	struct timespec timeout;
+
+	if (data_size == 0)
+		return (0);
+
+	timeout.tv_sec = NS_DEFAULT_CACHED_IO_TIMEOUT;
+	timeout.tv_nsec = 0;
+	result = 0;
+	do {
+		nevents = kevent(connection->write_queue, NULL, 0, &eventlist,
+		    1, &timeout);
+		if ((nevents == 1) && (eventlist.filter == EVFILT_WRITE)) {
+			s_result = _write(connection->sockfd, data + result,
+			    eventlist.data < data_size - result ?
+			    eventlist.data : data_size - result);
+			if (s_result == -1)
+				return (-1);
+			else
+				result += s_result;
+
+			if (eventlist.flags & EV_EOF)
+				return (result < data_size ? -1 : 0);
+		} else
+			return (-1);
+	} while (result < data_size);
+
+	return (0);
+}
+
+/*
+ * safe_read reads data from connection and tries to do it in the very safe
+ * and stable way. It uses kevent to ensure, that the data are availabe for
+ * reading. If the amount of data to be read is too large, then they would
+ * be splitted.
+ */
+static int
+safe_read(struct cached_connection_ *connection, void *data, size_t data_size)
+{
+	struct kevent eventlist;
+	size_t result;
+	ssize_t s_result;
+	struct timespec timeout;
+	int nevents;
+
+	if (data_size == 0)
+		return (0);
+
+	timeout.tv_sec = NS_DEFAULT_CACHED_IO_TIMEOUT;
+	timeout.tv_nsec = 0;
+	result = 0;
+	do {
+		nevents = kevent(connection->read_queue, NULL, 0, &eventlist,
+		    1, &timeout);
+		if (nevents == 1 && eventlist.filter == EVFILT_READ) {
+			s_result = _read(connection->sockfd, data + result,
+			    eventlist.data <= data_size - result ?
+			    eventlist.data : data_size - result);
+			if (s_result == -1)
+				return (-1);
+			else
+				result += s_result;
+
+			if (eventlist.flags & EV_EOF)
+				return (result < data_size ? -1 : 0);
+		} else
+			return (-1);
+	} while (result < data_size);
+
+	return (0);
+}
+
+/*
+ * Sends the credentials information to the connection along with the
+ * communication element type.
+ */
+static int
+send_credentials(struct cached_connection_ *connection, int type)
+{
+	struct kevent eventlist;
+	int nevents;
+	ssize_t result;
+	int res;
+
+	struct msghdr cred_hdr;
+	struct iovec iov;
+
+	struct {
+		struct cmsghdr hdr;
+		struct cmsgcred creds;
+	} cmsg;
+
+	memset(&cmsg, 0, sizeof(cmsg));
+	cmsg.hdr.cmsg_len = sizeof(cmsg);
+	cmsg.hdr.cmsg_level = SOL_SOCKET;
+	cmsg.hdr.cmsg_type = SCM_CREDS;
+
+	memset(&cred_hdr, 0, sizeof(struct msghdr));
+	cred_hdr.msg_iov = &iov;
+	cred_hdr.msg_iovlen = 1;
+	cred_hdr.msg_control = &cmsg;
+	cred_hdr.msg_controllen = sizeof(cmsg);
+
+	iov.iov_base = &type;
+	iov.iov_len = sizeof(int);
+
+	EV_SET(&eventlist, connection->sockfd, EVFILT_WRITE, EV_ADD,
+	    NOTE_LOWAT, sizeof(int), NULL);
+	res = kevent(connection->write_queue, &eventlist, 1, NULL, 0, NULL);
+
+	nevents = kevent(connection->write_queue, NULL, 0, &eventlist, 1,
+	    NULL);
+	if (nevents == 1 && eventlist.filter == EVFILT_WRITE) {
+		result = (_sendmsg(connection->sockfd, &cred_hdr, 0) == -1) ?
+		    -1 : 0;
+		EV_SET(&eventlist, connection->sockfd, EVFILT_WRITE, EV_ADD,
+		    0, 0, NULL);
+		kevent(connection->write_queue, &eventlist, 1, NULL, 0, NULL);
+		return (result);
+	} else
+		return (-1);
+}
+
+/*
+ * Opens the connection with the specified params. Initializes all kqueues.
+ */
+struct cached_connection_ *
+__open_cached_connection(struct cached_connection_params const *params)
+{
+	struct cached_connection_ *retval;
+	struct kevent eventlist;
+	struct sockaddr_un client_address;
+	int client_address_len, client_socket;
+	int res;
+
+	assert(params != NULL);
+
+	client_socket = _socket(PF_LOCAL, SOCK_STREAM, 0);
+	client_address.sun_family = PF_LOCAL;
+	strncpy(client_address.sun_path, params->socket_path,
+	    sizeof(client_address.sun_path));
+	client_address_len = sizeof(client_address.sun_family) +
+	    strlen(client_address.sun_path) + 1;
+
+	res = _connect(client_socket, (struct sockaddr *)&client_address,
+	    client_address_len);
+	if (res == -1) {
+		_close(client_socket);
+		return (NULL);
+	}
+	_fcntl(client_socket, F_SETFL, O_NONBLOCK);
+
+	retval = malloc(sizeof(struct cached_connection_));
+	assert(retval != NULL);
+	memset(retval, 0, sizeof(struct cached_connection_));
+
+	retval->sockfd = client_socket;
+
+	retval->write_queue = kqueue();
+	assert(retval->write_queue != -1);
+
+	EV_SET(&eventlist, retval->sockfd, EVFILT_WRITE, EV_ADD, 0, 0, NULL);
+	res = kevent(retval->write_queue, &eventlist, 1, NULL, 0, NULL);
+
+	retval->read_queue = kqueue();
+	assert(retval->read_queue != -1);
+
+	EV_SET(&eventlist, retval->sockfd, EVFILT_READ, EV_ADD, 0, 0, NULL);
+	res = kevent(retval->read_queue, &eventlist, 1, NULL, 0, NULL);
+
+	return (retval);
+}
+
+void
+__close_cached_connection(struct cached_connection_ *connection)
+{
+	assert(connection != NULL);
+
+	_close(connection->sockfd);
+	_close(connection->read_queue);
+	_close(connection->write_queue);
+	free(connection);
+}
+
+/*
+ * This function is very close to the cache_write function of the caching
+ * library, which is used in the caching daemon. It caches the data with the
+ * specified key in the cache entry with entry_name.
+ */
+int
+__cached_write(struct cached_connection_ *connection, const char *entry_name,
+    const char *key, size_t key_size, const char *data, size_t data_size)
+{
+	size_t name_size;
+	int error_code;
+	int result;
+
+	error_code = -1;
+	result = 0;
+	result = send_credentials(connection, CET_WRITE_REQUEST);
+	if (result != 0)
+		goto fin;
+
+	name_size = strlen(entry_name);
+	result = safe_write(connection, &name_size, sizeof(size_t));
+	if (result != 0)
+		goto fin;
+
+	result = safe_write(connection, &key_size, sizeof(size_t));
+	if (result != 0)
+		goto fin;
+
+	result = safe_write(connection, &data_size, sizeof(size_t));
+	if (result != 0)
+		goto fin;
+
+	result = safe_write(connection, entry_name, name_size);
+	if (result != 0)
+		goto fin;
+
+	result = safe_write(connection, key, key_size);
+	if (result != 0)
+		goto fin;
+
+	result = safe_write(connection, data, data_size);
+	if (result != 0)
+		goto fin;
+
+	result = safe_read(connection, &error_code, sizeof(int));
+	if (result != 0)
+		error_code = -1;
+
+fin:
+	return (error_code);
+}
+
+/*
+ * This function is very close to the cache_read function of the caching
+ * library, which is used in the caching daemon. It reads cached data with the
+ * specified key from the cache entry with entry_name.
+ */
+int
+__cached_read(struct cached_connection_ *connection, const char *entry_name,
+    const char *key, size_t key_size, char *data, size_t *data_size)
+{
+	size_t name_size, result_size;
+	int error_code, rec_error_code;
+	int result;
+
+	assert(connection != NULL);
+	result = 0;
+	error_code = -1;
+
+	result = send_credentials(connection, CET_READ_REQUEST);
+	if (result != 0)
+		goto fin;
+
+	name_size = strlen(entry_name);
+	result = safe_write(connection, &name_size, sizeof(size_t));
+	if (result != 0)
+		goto fin;
+
+	result = safe_write(connection, &key_size, sizeof(size_t));
+	if (result != 0)
+		goto fin;
+
+	result = safe_write(connection, entry_name, name_size);
+	if (result != 0)
+		goto fin;
+
+	result = safe_write(connection, key, key_size);
+	if (result != 0)
+		goto fin;
+
+	result = safe_read(connection, &rec_error_code, sizeof(int));
+	if (result != 0)
+		goto fin;
+
+	if (rec_error_code != 0) {
+		error_code = rec_error_code;
+		goto fin;
+	}
+
+	result = safe_read(connection, &result_size, sizeof(size_t));
+	if (result != 0)
+		goto fin;
+
+	 if (result_size > *data_size) {
+		 *data_size = result_size;
+		 error_code = -2;
+		 goto fin;
+	 }
+
+	result = safe_read(connection, data, result_size);
+	if (result != 0)
+		goto fin;
+
+	*data_size = result_size;
+	error_code = 0;
+
+fin:
+	return (error_code);
+}
+
+/*
+ * Initializes the mp_write_session. For such a session the new connection
+ * would be opened. The data should be written to the session with
+ * __cached_mp_write function. The __close_cached_mp_write_session function
+ * should be used to submit session and __abandon_cached_mp_write_session - to
+ * abandon it. When the session is submitted, the whole se
+ */
+struct cached_connection_ *
+__open_cached_mp_write_session(struct cached_connection_params const *params,
+    const char *entry_name)
+{
+	struct cached_connection_ *connection, *retval;
+	size_t name_size;
+	int error_code;
+	int result;
+
+	retval = NULL;
+	connection = __open_cached_connection(params);
+	if (connection == NULL)
+		return (NULL);
+	connection->mp_flag = 1;
+
+	result = send_credentials(connection, CET_MP_WRITE_SESSION_REQUEST);
+	if (result != 0)
+		goto fin;
+
+	name_size = strlen(entry_name);
+	result = safe_write(connection, &name_size, sizeof(size_t));
+	if (result != 0)
+		goto fin;
+
+	result = safe_write(connection, entry_name, name_size);
+	if (result != 0)
+		goto fin;
+
+	result = safe_read(connection, &error_code, sizeof(int));
+	if (result != 0)
+		goto fin;
+
+	if (error_code != 0)
+		result = error_code;
+
+fin:
+	if (result != 0)
+		__close_cached_connection(connection);
+	else
+		retval = connection;
+	return (retval);
+}
+
+/*
+ * Adds new portion of data to the opened write session
+ */
+int
+__cached_mp_write(struct cached_connection_ *ws, const char *data,
+    size_t data_size)
+{
+	int request, result;
+	int error_code;
+
+	error_code = -1;
+
+	request = CET_MP_WRITE_SESSION_WRITE_REQUEST;
+	result = safe_write(ws, &request, sizeof(int));
+	if (result != 0)
+		goto fin;
+
+	result = safe_write(ws, &data_size, sizeof(size_t));
+	if (result != 0)
+		goto fin;
+
+	result = safe_write(ws, data, data_size);
+	if (result != 0)
+		goto fin;
+
+	result = safe_read(ws, &error_code, sizeof(int));
+	if (result != 0)
+		error_code = -1;
+
+fin:
+	return (error_code);
+}
+
+/*
+ * Abandons all operations with the write session. All data, that were written
+ * to the session before, are discarded.
+ */
+int
+__abandon_cached_mp_write_session(struct cached_connection_ *ws)
+{
+	int notification;
+	int result;
+
+	notification = CET_MP_WRITE_SESSION_ABANDON_NOTIFICATION;
+	result = safe_write(ws, &notification, sizeof(int));
+	__close_cached_connection(ws);
+	return (result);
+}
+
+/*
+ * Gracefully closes the write session. The data, that were previously written
+ * to the session, are committed.
+ */
+int
+__close_cached_mp_write_session(struct cached_connection_ *ws)
+{
+	int notification;
+	int result;
+
+	notification = CET_MP_WRITE_SESSION_CLOSE_NOTIFICATION;
+	result = safe_write(ws, &notification, sizeof(int));
+	__close_cached_connection(ws);
+	return (0);
+}
+
+struct cached_connection_ *
+__open_cached_mp_read_session(struct cached_connection_params const *params,
+	const char *entry_name)
+{
+	struct cached_connection_ *connection, *retval;
+	size_t name_size;
+	int error_code;
+	int result;
+
+	retval = NULL;
+	connection = __open_cached_connection(params);
+	if (connection == NULL)
+		return (NULL);
+	connection->mp_flag = 1;
+
+	result = send_credentials(connection, CET_MP_READ_SESSION_REQUEST);
+	if (result != 0)
+		goto fin;
+
+	name_size = strlen(entry_name);
+	result = safe_write(connection, &name_size, sizeof(size_t));
+	if (result != 0)
+		goto fin;
+
+	result = safe_write(connection, entry_name, name_size);
+	if (result != 0)
+		goto fin;
+
+	result = safe_read(connection, &error_code, sizeof(int));
+	if (result != 0)
+		goto fin;
+
+	if (error_code != 0)
+		result = error_code;
+
+fin:
+	if (result != 0)
+		__close_cached_connection(connection);
+	else
+		retval = connection;
+	return (retval);
+}
+
+int
+__cached_mp_read(struct cached_connection_ *rs, char *data, size_t *data_size)
+{
+	size_t result_size;
+	int error_code, rec_error_code;
+	int request, result;
+
+	error_code = -1;
+	request = CET_MP_READ_SESSION_READ_REQUEST;
+	result = safe_write(rs, &request, sizeof(int));
+	if (result != 0)
+		goto fin;
+
+	result = safe_read(rs, &rec_error_code, sizeof(int));
+	if (result != 0)
+		goto fin;
+
+	if (rec_error_code != 0) {
+		error_code = rec_error_code;
+		goto fin;
+	}
+
+	result = safe_read(rs, &result_size, sizeof(size_t));
+	if (result != 0)
+		goto fin;
+
+	if (result_size > *data_size) {
+		*data_size = result_size;
+		error_code = -2;
+		goto fin;
+	}
+
+	result = safe_read(rs, data, result_size);
+	if (result != 0)
+		goto fin;
+
+	*data_size = result_size;
+	error_code = 0;
+
+fin:
+	return (error_code);
+}
+
+int
+__close_cached_mp_read_session(struct cached_connection_ *rs)
+{
+
+	__close_cached_connection(rs);
+	return (0);
+}