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/*

 * Copyright (c) 2008 Jakub Jermar 

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - 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.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.

 */

/** @addtogroup libfs 

 * @{

 */ 

/**

 * @file

 * Glue code which is commonod to all FS implementations. 

 */

#include "libfs.h" 

#include "../../srv/vfs/vfs.h"

#include <errno.h>

#include <async.h>

#include <ipc/ipc.h>

#include <as.h>

#include <assert.h>

#include <dirent.h>

/** Register file system server.

 *

 * This function abstracts away the tedious registration protocol from

 * file system implementations and lets them to reuse this registration glue

 * code.

 *

 * @param vfs_phone	Open phone for communication with VFS.

 * @param reg		File system registration structure. It will be

 * 			initialized by this function.

 * @param info		VFS info structure supplied by the file system

 *			implementation.

 * @param conn		Connection fibril for handling all calls originating in

 *			VFS.

 *

 * @return		EOK on success or a non-zero error code on errror.

 */

int fs_register(int vfs_phone, fs_reg_t *reg, vfs_info_t *info,

    async_client_conn_t conn)

{

	/*

	 * Tell VFS that we are here and want to get registered.

	 * We use the async framework because VFS will answer the request

	 * out-of-order, when it knows that the operation succeeded or failed.

	 */

	ipc_call_t answer;

	aid_t req = async_send_0(vfs_phone, VFS_REGISTER, &answer);

	/*

	 * Send our VFS info structure to VFS.

	 */

	int rc = ipc_data_write_start(vfs_phone, info, sizeof(*info)); 

	if (rc != EOK) {

		async_wait_for(req, NULL);

		return rc;

	}

	/*

	 * Ask VFS for callback connection.

	 */

	ipc_connect_to_me(vfs_phone, 0, 0, 0, &reg->vfs_phonehash);

	/*

	 * Allocate piece of address space for PLB.

	 */

	reg->plb_ro = as_get_mappable_page(PLB_SIZE);

	if (!reg->plb_ro) {

		async_wait_for(req, NULL);

		return ENOMEM;

	}

	/*

	 * Request sharing the Path Lookup Buffer with VFS.

	 */

	rc = ipc_share_in_start_0_0(vfs_phone, reg->plb_ro, PLB_SIZE);

	if (rc) {

		async_wait_for(req, NULL);

		return rc;

	}

	/*

	 * Pick up the answer for the request to the VFS_REQUEST call.

	 */

	async_wait_for(req, NULL);

	reg->fs_handle = (int) IPC_GET_ARG1(answer);

	/*

	 * Create a connection fibril to handle the callback connection.

	 */

	async_new_connection(reg->vfs_phonehash, 0, NULL, conn);

	/*

	 * Tell the async framework that other connections are to be handled by

	 * the same connection fibril as well.

	 */

	async_set_client_connection(conn);

	return IPC_GET_RETVAL(answer);

}

/** Lookup VFS triplet by name in the file system name space.

 *

 * The path passed in the PLB must be in the canonical file system path format

 * as returned by the canonify() function.

 *

 * @param ops		libfs operations structure with function pointers to

 *			file system implementation

 * @param fs_handle	File system handle of the file system where to perform

 *			the lookup.

 * @param rid		Request ID of the VFS_LOOKUP request.

 * @param request	VFS_LOOKUP request data itself.

 */

void libfs_lookup(libfs_ops_t *ops, fs_handle_t fs_handle, ipc_callid_t rid,

    ipc_call_t *request)

{

	unsigned next = IPC_GET_ARG1(*request);

	unsigned last = IPC_GET_ARG2(*request);

	dev_handle_t dev_handle = IPC_GET_ARG3(*request);

	int lflag = IPC_GET_ARG4(*request);

	fs_index_t index = IPC_GET_ARG5(*request); /* when L_LINK specified */

	char component[NAME_MAX + 1];

	int len;

	if (last < next)

		last += PLB_SIZE;

	void *par = NULL;

	void *cur = ops->root_get(dev_handle);

	if (ops->plb_get_char(next) == '/')

		next++;		/* eat slash */

	while (ops->has_children(cur) && next <= last) {

		void *tmp;

		/* collect the component */

		len = 0;

		while ((ops->plb_get_char(next) != '/') && (next <= last)) {

			if (len + 1 == NAME_MAX) {

				/* comopnent length overflow */

				ipc_answer_0(rid, ENAMETOOLONG);

				return;

			}

			component[len++] = ops->plb_get_char(next);

			next++;	/* process next character */

		}

		assert(len);

		component[len] = '\0';

		next++;		/* eat slash */

		/* match the component */

		tmp = ops->match(cur, component);

		/* handle miss: match amongst siblings */

		if (!tmp) {

			if (next <= last) {

				/* there are unprocessed components */

				ipc_answer_0(rid, ENOENT);

				return;

			}

			/* miss in the last component */

			if (lflag & (L_CREATE | L_LINK)) { 

				/* request to create a new link */

				if (!ops->is_directory(cur)) {

					ipc_answer_0(rid, ENOTDIR);

					return;

				}

				void *nodep;

				if (lflag & L_CREATE)

					nodep = ops->create(lflag);

				else

					nodep = ops->node_get(dev_handle,

					    index, ops->index_get(cur));

				if (nodep) {

					if (!ops->link(cur, nodep, component)) {

						if (lflag & L_CREATE)

							ops->destroy(nodep);

						ipc_answer_0(rid, ENOSPC);

					} else {

						ipc_answer_5(rid, EOK,

						    fs_handle, dev_handle,

						    ops->index_get(nodep),

						    ops->size_get(nodep),

						    ops->lnkcnt_get(nodep));

					}

				} else {

					ipc_answer_0(rid, ENOSPC);

				}

				return;

			} else if (lflag & L_PARENT) {

				/* return parent */

				ipc_answer_5(rid, EOK, fs_handle, dev_handle,

				    ops->index_get(cur), ops->size_get(cur),

				    ops->lnkcnt_get(cur));

			} 

			ipc_answer_0(rid, ENOENT);

			return;

		}

		/* descend one level */

		par = cur;

		cur = tmp;

	}

	/* handle miss: excessive components */

	if (!ops->has_children(cur) && next <= last) {

		if (lflag & (L_CREATE | L_LINK)) {

			if (!ops->is_directory(cur)) {

				ipc_answer_0(rid, ENOTDIR);

				return;

			}

			/* collect next component */

			len = 0;

			while (next <= last) {

				if (ops->plb_get_char(next) == '/') {

					/* more than one component */

					ipc_answer_0(rid, ENOENT);

					return;

				}

				if (len + 1 == NAME_MAX) {

					/* component length overflow */

					ipc_answer_0(rid, ENAMETOOLONG);

					return;

				}

				component[len++] = ops->plb_get_char(next);

				next++;	/* process next character */

			}

			assert(len);

			component[len] = '\0';

			void *nodep;

			if (lflag & L_CREATE)

				nodep = ops->create(lflag);

			else

				nodep = ops->node_get(dev_handle, index,

				    ops->index_get(cur));

			if (nodep) {

				if (!ops->link(cur, nodep, component)) {

					if (lflag & L_CREATE)

						ops->destroy(nodep);

					ipc_answer_0(rid, ENOSPC);

				} else {

					ipc_answer_5(rid, EOK,

					    fs_handle, dev_handle,

					    ops->index_get(nodep),

					    ops->size_get(nodep),

					    ops->lnkcnt_get(nodep));

				}

			} else {

				ipc_answer_0(rid, ENOSPC);

			}

			return;

		}

		ipc_answer_0(rid, ENOENT);

		return;

	}

	/* handle hit */

	if (lflag & L_PARENT) {

		cur = par;

		if (!cur) {

			ipc_answer_0(rid, ENOENT);

			return;

		}

	}

	if (lflag & L_UNLINK) {

		unsigned old_lnkcnt = ops->lnkcnt_get(cur);

		int res = ops->unlink(par, cur);

		ipc_answer_5(rid, (ipcarg_t)res, fs_handle, dev_handle,

		    ops->index_get(cur), ops->size_get(cur), old_lnkcnt);

		return;

	}

	if (((lflag & (L_CREATE | L_EXCLUSIVE)) == (L_CREATE | L_EXCLUSIVE)) ||

	    (lflag & L_LINK)) {

		ipc_answer_0(rid, EEXIST);

		return;

	}

	if ((lflag & L_FILE) && (ops->is_directory(cur))) {

		ipc_answer_0(rid, EISDIR);

		return;

	}

	if ((lflag & L_DIRECTORY) && (ops->is_file(cur))) {

		ipc_answer_0(rid, ENOTDIR);

		return;

	}

	ipc_answer_5(rid, EOK, fs_handle, dev_handle, ops->index_get(cur),

	    ops->size_get(cur), ops->lnkcnt_get(cur));

}

/** @}

 */