WebSVN – HelenOS – Blame – /trunk/uspace/srv/vfs/vfs_open.c

Rev	Author	Line No.	Line
2560	jermar	1	/*
		2	* Copyright (c) 2007 Jakub Jermar
		3	* All rights reserved.
		4	*
		5	* Redistribution and use in source and binary forms, with or without
		6	* modification, are permitted provided that the following conditions
		7	* are met:
		8	*
		9	* - Redistributions of source code must retain the above copyright
		10	* notice, this list of conditions and the following disclaimer.
		11	* - Redistributions in binary form must reproduce the above copyright
		12	* notice, this list of conditions and the following disclaimer in the
		13	* documentation and/or other materials provided with the distribution.
		14	* - The name of the author may not be used to endorse or promote products
		15	* derived from this software without specific prior written permission.
		16	*
		17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
		18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
		19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
		20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
		21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
		22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
		23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
		24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
		25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
		26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
		27	*/
		28
		29	/** @addtogroup fs
		30	* @{
		31	*/
		32
		33	/**
2590	jermar	34	* @file vfs_open.c
2560	jermar	35	* @brief VFS_OPEN method.
		36	*/
		37
		38	#include <ipc/ipc.h>
		39	#include <async.h>
		40	#include <errno.h>
		41	#include <stdlib.h>
		42	#include <string.h>
		43	#include <bool.h>
		44	#include <futex.h>
		45	#include <libadt/list.h>
2589	jermar	46	#include <sys/types.h>
2560	jermar	47	#include "vfs.h"
		48
2589	jermar	49	/** Per-connection futex protecting the files array. */
		50	__thread atomic_t files_futex = FUTEX_INITIALIZER;
		51
2560	jermar	52	/**
		53	* This is a per-connection table of open files.
		54	* Our assumption is that each client opens only one connection and therefore
		55	* there is one table of open files per task. However, this may not be the case
		56	* and the client can open more connections to VFS. In that case, there will be
		57	* several tables and several file handle name spaces per task. Besides of this,
		58	* the functionality will stay unchanged. So unless the client knows what it is
		59	* doing, it should open one connection to VFS only.
2589	jermar	60	*
		61	* Allocation of the open files table is deferred until the client makes the
		62	* first VFS_OPEN operation.
2560	jermar	63	*/
2589	jermar	64	__thread vfs_file_t *files = NULL;
2560	jermar	65
		66	/** Initialize the table of open files. */
2589	jermar	67	static bool vfs_conn_open_files_init(void)
2560	jermar	68	{
2590	jermar	69	/*
		70	* Optimized fast path that will never go to sleep unnecessarily.
		71	* The assumption is that once files is non-zero, it will never be zero
		72	* again.
		73	*/
		74	if (files)
		75	return true;
		76
2589	jermar	77	futex_down(&files_futex);
		78	if (!files) {
		79	files = malloc(MAX_OPEN_FILES * sizeof(vfs_file_t));
		80	if (!files) {
		81	futex_up(&files_futex);
		82	return false;
		83	}
		84	memset(files, 0, MAX_OPEN_FILES * sizeof(vfs_file_t));
		85	}
		86	futex_up(&files_futex);
2560	jermar	87	return true;
		88	}
		89
		90	void vfs_open(ipc_callid_t rid, ipc_call_t *request)
		91	{
2589	jermar	92	if (!vfs_conn_open_files_init()) {
		93	ipc_answer_fast_0(rid, ENOMEM);
		94	return;
		95	}
2590	jermar	96
		97	/*
		98	* The POSIX interface is open(path, flags, mode).
		99	* We can receive flags and mode along with the VFS_OPEN call; the path
		100	* will need to arrive in another call.
		101	*/
		102	int flags = IPC_GET_ARG1(*request);
		103	int mode = IPC_GET_ARG2(*request);
		104	size_t size;
		105
		106	ipc_callid_t callid;
		107	ipc_call_t call;
		108
		109	if (!ipc_data_receive(&callid, &call, NULL, &size)) {
		110	ipc_answer_fast_0(callid, EINVAL);
		111	ipc_answer_fast_0(rid, EINVAL);
		112	return;
		113	}
		114
		115	/*
		116	* Now we are on the verge of accepting the path.
		117	*
		118	* There is one optimization we could do in the future: copy the path
		119	* directly into the PLB using some kind of a callback.
		120	*/
		121	char *path = malloc(size);
		122
		123	if (!path) {
		124	ipc_answer_fast_0(callid, ENOMEM);
		125	ipc_answer_fast_0(rid, ENOMEM);
		126	return;
		127	}
		128
		129	int rc;
		130	if (rc = ipc_data_deliver(callid, &call, path, size)) {
		131	ipc_answer_fast_0(rid, rc);
		132	free(path);
		133	return;
		134	}
		135
		136	/*
		137	* The path is now populated and we can call vfs_lookup_internal().
		138	*/
		139	vfs_triplet_t triplet;
		140	rc = vfs_lookup_internal(path, size, &triplet, NULL);
		141	if (rc) {
		142	ipc_answer_fast_0(rid, rc);
		143	free(path);
		144	return;
		145	}
		146
		147	/*
		148	* Path is no longer needed.
		149	*/
		150	free(path);
		151
		152	vfs_node_t *node = vfs_node_get(&triplet);
		153	// TODO: not finished
2560	jermar	154	}
		155
		156	/**
		157	* @}
		158	*/

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(root)/trunk/uspace/srv/vfs/vfs_open.c – Rev 2590