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

Rev	Author	Line No.	Line
2542	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	/**
		34	* @file vfs.c
		35	* @brief VFS_MOUNT 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>
		46	#include "vfs.h"
		47
2552	jermar	48	vfs_node_t rootfs = { 0 };
2542	jermar	49
2552	jermar	50	static int lookup_root(int fs_handle, int dev_handle, vfs_node_t *root)
		51	{
		52	vfs_node_t altroot = {
		53	.fs_handle = fs_handle,
		54	.dev_handle = dev_handle,
		55	/*
		56	* At this point, we don't know what is the index of the root
		57	* node. Finally, that's what this function is about.
		58	*/
		59	};
		60
		61	return vfs_lookup_internal("/", 1, root, &altroot);
		62	}
		63
2542	jermar	64	void vfs_mount(ipc_callid_t rid, ipc_call_t *request)
		65	{
2552	jermar	66	int dev_handle;
		67
		68	/*
		69	* We expect the library to do the device-name to device-handle
		70	* translation for us, thus the device handle will arrive as ARG1
		71	* in the request.
		72	*/
		73	dev_handle = IPC_GET_ARG1(*request);
		74
		75	/*
		76	* For now, don't make use of ARG2 and ARG3, but they can be used to
		77	* carry mount options in the future.
		78	*/
		79
		80	/*
		81	* Now, we expect the client to send us data with the name of the file
		82	* system and the path of the mountpoint.
		83	*/
		84	ipc_callid_t callid;
		85	ipc_call_t call;
		86	size_t size;
		87	if (!ipc_data_receive(&callid, &call, NULL, &size)) {
		88	ipc_answer_fast(callid, EINVAL, 0, 0);
		89	ipc_answer_fast(rid, EINVAL, 0, 0);
		90	return;
		91	}
		92
		93	/*
		94	* There is no sense in receiving data that can't hold a single
		95	* character of path. We won't accept data that exceed certain limits
		96	* either.
		97	*/
		98	if ((size < FS_NAME_MAXLEN + 1) \|\|
		99	(size > FS_NAME_MAXLEN + MAX_PATH_LEN)) {
		100	ipc_answer_fast(callid, EINVAL, 0, 0);
		101	ipc_answer_fast(rid, EINVAL, 0, 0);
		102	return;
		103	}
		104
		105	/*
		106	* Allocate buffer for the data being received.
		107	*/
		108	uint8_t *buf;
		109	buf = malloc(size);
		110	if (!buf) {
		111	ipc_answer_fast(callid, ENOMEM, 0, 0);
		112	ipc_answer_fast(rid, ENOMEM, 0, 0);
		113	return;
		114	}
		115
		116	/*
		117	* Deliver the data.
		118	*/
		119	(void) ipc_data_deliver(callid, &call, buf, size);
		120
		121	char fs_name[FS_NAME_MAXLEN + 1];
		122	memcpy(fs_name, buf, FS_NAME_MAXLEN);
		123	fs_name[FS_NAME_MAXLEN] = '\0';
		124
		125	/*
		126	* Check if we know a file system with the same name as is in fs_name.
		127	* This will also give us its file system handle.
		128	*/
		129	int fs_handle = fs_name_to_handle(fs_name, true);
		130	if (!fs_handle) {
		131	free(buf);
		132	ipc_answer_fast(rid, ENOENT, 0, 0);
		133	return;
		134	}
		135
		136	/*
		137	* Lookup the root node of the filesystem being mounted.
		138	*/
		139	int rc;
		140	vfs_node_t mounted_root;
		141	rc = lookup_root(fs_handle, dev_handle, &mounted_root);
		142	if (rc != EOK) {
		143	free(buf);
		144	ipc_answer_fast(rid, rc, 0, 0);
		145	return;
		146	}
		147
		148	/*
		149	* Finally, we need to resolve the path to the mountpoint.
		150	*/
		151	vfs_node_t mp;
		152	if (rootfs.fs_handle) {
		153	/*
		154	* We already have the root FS.
		155	*/
		156	rc = vfs_lookup_internal((char *) (buf + FS_NAME_MAXLEN),
		157	size - FS_NAME_MAXLEN, &mp, NULL);
		158	if (rc != EOK) {
		159	/*
		160	* The lookup failed for some reason.
		161	*/
		162	free(buf);
		163	ipc_answer_fast(rid, rc, 0, 0);
		164	return;
		165	}
		166	} else {
		167	/*
		168	* We still don't have the root file system mounted.
		169	*/
		170	if ((size - FS_NAME_MAXLEN == 1) &&
		171	(buf[FS_NAME_MAXLEN] == '/')) {
		172	/*
		173	* For this simple, but important case, we are done.
		174	*/
		175	rootfs = mounted_root;
		176	free(buf);
		177	ipc_answer_fast(rid, EOK, 0, 0);
		178	return;
		179	} else {
		180	/*
		181	* We can't resolve this without the root filesystem
		182	* being mounted first.
		183	*/
		184	free(buf);
		185	ipc_answer_fast(rid, ENOENT, 0, 0);
		186	return;
		187	}
		188	}
		189
		190	/*
		191	* At this point, we have all necessary pieces: file system and device
		192	* handles, and we know the mount point VFS node and also the root node
		193	* of the file system being mounted.
		194	*/
		195
2542	jermar	196	}
		197
		198	/**
		199	* @}
		200	*/

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(root)/trunk/uspace/srv/vfs/vfs_mount.c @ 2588 – Rev 2552