DrvChar.cpp@ 1754

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1	/** @file
2	*
3	* VBox stream I/O devices:
4	* Generic char driver
5	*/
6
7	/*
8	* Copyright (C) 2006 InnoTek Systemberatung GmbH
9	*
10	* This file is part of VirtualBox Open Source Edition (OSE), as
11	* available from http://www.virtualbox.org. This file is free software;
12	* you can redistribute it and/or modify it under the terms of the GNU
13	* General Public License as published by the Free Software Foundation,
14	* in version 2 as it comes in the "COPYING" file of the VirtualBox OSE
15	* distribution. VirtualBox OSE is distributed in the hope that it will
16	* be useful, but WITHOUT ANY WARRANTY of any kind.
17	*
18	* If you received this file as part of a commercial VirtualBox
19	* distribution, then only the terms of your commercial VirtualBox
20	* license agreement apply instead of the previous paragraph.
21	*/
22
23
24
25	/*******************************************************************************
26	* Header Files *
27	*******************************************************************************/
28	#define LOG_GROUP LOG_GROUP_DRV_CHAR
29	#include <VBox/pdm.h>
30	#include <VBox/err.h>
31
32	#include <VBox/log.h>
33	#include <iprt/asm.h>
34	#include <iprt/assert.h>
35	#include <iprt/stream.h>
36	#include <iprt/semaphore.h>
37
38	#include "Builtins.h"
39
40
41	/** Size of the send fifo queue (in bytes) */
42	#define CHAR_MAX_SEND_QUEUE 0x80
43	#define CHAR_MAX_SEND_QUEUE_MASK 0x7f
44
45	/*******************************************************************************
46	* Structures and Typedefs *
47	*******************************************************************************/
48
49	/**
50	* Char driver instance data.
51	*/
52	typedef struct DRVCHAR
53	{
54	/** Pointer to the driver instance structure. */
55	PPDMDRVINS pDrvIns;
56	/** Pointer to the char port interface of the driver/device above us. */
57	PPDMICHARPORT pDrvCharPort;
58	/** Pointer to the stream interface of the driver below us. */
59	PPDMISTREAM pDrvStream;
60	/** Our char interface. */
61	PDMICHAR IChar;
62	/** Flag to notify the receive thread it should terminate. */
63	volatile bool fShutdown;
64	/** Receive thread ID. */
65	RTTHREAD ReceiveThread;
66	/** Send thread ID. */
67	RTTHREAD SendThread;
68	/** Send event semephore */
69	RTSEMEVENT SendSem;
70
71	/** Internal send FIFO queue */
72	uint8_t aSendQueue[CHAR_MAX_SEND_QUEUE];
73	uint32_t iSendQueueHead;
74	uint32_t iSendQueueTail;
75
76	/** Read/write statistics */
77	STAMCOUNTER StatBytesRead;
78	STAMCOUNTER StatBytesWritten;
79	} DRVCHAR, *PDRVCHAR;
80
81
82	/** Converts a pointer to DRVCHAR::IChar to a PDRVCHAR. */
83	#define PDMICHAR_2_DRVCHAR(pInterface) ( (PDRVCHAR)((uintptr_t)pInterface - RT_OFFSETOF(DRVCHAR, IChar)) )
84
85
86	/* -=-=-=-=- IBase -=-=-=-=- */
87
88	/**
89	* Queries an interface to the driver.
90	*
91	* @returns Pointer to interface.
92	* @returns NULL if the interface was not supported by the driver.
93	* @param pInterface Pointer to this interface structure.
94	* @param enmInterface The requested interface identification.
95	*/
96	static DECLCALLBACK(void *) drvCharQueryInterface(PPDMIBASE pInterface, PDMINTERFACE enmInterface)
97	{
98	PPDMDRVINS pDrvIns = PDMIBASE_2_PDMDRV(pInterface);
99	PDRVCHAR pData = PDMINS2DATA(pDrvIns, PDRVCHAR);
100	switch (enmInterface)
101	{
102	case PDMINTERFACE_BASE:
103	return &pDrvIns->IBase;
104	case PDMINTERFACE_CHAR:
105	return &pData->IChar;
106	default:
107	return NULL;
108	}
109	}
110
111
112	/* -=-=-=-=- IChar -=-=-=-=- */
113
114	/** @copydoc PDMICHAR::pfnWrite */
115	static DECLCALLBACK(int) drvCharWrite(PPDMICHAR pInterface, const void *pvBuf, size_t cbWrite)
116	{
117	PDRVCHAR pData = PDMICHAR_2_DRVCHAR(pInterface);
118	const char pBuffer = (const char )pvBuf;
119	int rc = VINF_SUCCESS;
120
121	LogFlow(("%s: pvBuf=%#p cbWrite=%d\n", __FUNCTION__, pvBuf, cbWrite));
122
123	for (uint32_t i=0;i<cbWrite;i++)
124	{
125	uint32_t idx = pData->iSendQueueHead;
126
127	pData->aSendQueue[idx] = pBuffer[i];
128	idx = (idx + 1) & CHAR_MAX_SEND_QUEUE_MASK;
129
130	STAM_COUNTER_INC(&pData->StatBytesWritten);
131	ASMAtomicXchgU32(&pData->iSendQueueHead, idx);
132	}
133	RTSemEventSignal(pData->SendSem);
134	return VINF_SUCCESS;
135	}
136
137
138	/* -=-=-=-=- receive thread -=-=-=-=- */
139
140	/**
141	* Send thread loop.
142	*
143	* @returns 0 on success.
144	* @param ThreadSelf Thread handle to this thread.
145	* @param pvUser User argument.
146	*/
147	static DECLCALLBACK(int) drvCharSendLoop(RTTHREAD ThreadSelf, void *pvUser)
148	{
149	PDRVCHAR pData = (PDRVCHAR)pvUser;
150
151	for(;;)
152	{
153	int rc = RTSemEventWait(pData->SendSem, RT_INDEFINITE_WAIT);
154	if (VBOX_FAILURE(rc))
155	break;
156
157	/*
158	* Write the character to the attached stream (if present).
159	*/
160	if ( !pData->fShutdown
161	&& pData->pDrvStream)
162	{
163	while (pData->iSendQueueTail != pData->iSendQueueHead)
164	{
165	size_t cbProcessed = 1;
166
167	rc = pData->pDrvStream->pfnWrite(pData->pDrvStream, &pData->aSendQueue[pData->iSendQueueTail], &cbProcessed);
168	if (VBOX_SUCCESS(rc))
169	{
170	Assert(cbProcessed);
171	pData->iSendQueueTail++;
172	pData->iSendQueueTail &= CHAR_MAX_SEND_QUEUE_MASK;
173	}
174	else if (rc == VERR_TIMEOUT)
175	{
176	/* Normal case, just means that the stream didn't accept a new
177	* character before the timeout elapsed. Just retry. */
178	rc = VINF_SUCCESS;
179	}
180	else
181	{
182	Log(("Write failed with %Vrc; skipping\n", rc));
183	break;
184	}
185	}
186	}
187	else
188	break;
189	}
190
191	pData->SendThread = NIL_RTTHREAD;
192
193	return VINF_SUCCESS;
194	}
195
196
197	/* -=-=-=-=- receive thread -=-=-=-=- */
198
199	/**
200	* Receive thread loop.
201	*
202	* @returns 0 on success.
203	* @param ThreadSelf Thread handle to this thread.
204	* @param pvUser User argument.
205	*/
206	static DECLCALLBACK(int) drvCharReceiveLoop(RTTHREAD ThreadSelf, void *pvUser)
207	{
208	PDRVCHAR pData = (PDRVCHAR)pvUser;
209	char aBuffer[256], *pBuffer;
210	size_t cbRemaining, cbProcessed;
211	int rc;
212
213	cbRemaining = 0;
214	pBuffer = aBuffer;
215	while (!pData->fShutdown)
216	{
217	if (!cbRemaining)
218	{
219	/* Get block of data from stream driver. */
220	if (pData->pDrvStream)
221	{
222	cbRemaining = sizeof(aBuffer);
223	rc = pData->pDrvStream->pfnRead(pData->pDrvStream, aBuffer, &cbRemaining);
224	AssertRC(rc);
225	}
226	else
227	{
228	cbRemaining = 0;
229	RTThreadSleep(100);
230	}
231	pBuffer = aBuffer;
232	}
233	else
234	{
235	/* Send data to guest. */
236	cbProcessed = cbRemaining;
237	rc = pData->pDrvCharPort->pfnNotifyRead(pData->pDrvCharPort, pBuffer, &cbProcessed);
238	if (VBOX_SUCCESS(rc))
239	{
240	Assert(cbProcessed);
241	pBuffer += cbProcessed;
242	cbRemaining -= cbProcessed;
243	STAM_COUNTER_ADD(&pData->StatBytesRead, cbProcessed);
244	}
245	else if (rc == VERR_TIMEOUT)
246	{
247	/* Normal case, just means that the guest didn't accept a new
248	* character before the timeout elapsed. Just retry. */
249	rc = VINF_SUCCESS;
250	}
251	else
252	AssertRC(rc);
253	}
254	}
255
256	pData->ReceiveThread = NIL_RTTHREAD;
257
258	return VINF_SUCCESS;
259	}
260
261
262	/* -=-=-=-=- driver interface -=-=-=-=- */
263
264	/**
265	* Construct a char driver instance.
266	*
267	* @returns VBox status.
268	* @param pDrvIns The driver instance data.
269	* If the registration structure is needed,
270	* pDrvIns->pDrvReg points to it.
271	* @param pCfgHandle Configuration node handle for the driver. Use this to
272	* obtain the configuration of the driver instance. It's
273	* also found in pDrvIns->pCfgHandle as it's expected to
274	* be used frequently in this function.
275	*/
276	static DECLCALLBACK(int) drvCharConstruct(PPDMDRVINS pDrvIns, PCFGMNODE pCfgHandle)
277	{
278	PDRVCHAR pData = PDMINS2DATA(pDrvIns, PDRVCHAR);
279	LogFlow(("%s: iInstance=%d\n", __FUNCTION__, pDrvIns->iInstance));
280
281	/*
282	* Init basic data members and interfaces.
283	*/
284	pData->ReceiveThread = NIL_RTTHREAD;
285	pData->fShutdown = false;
286	/* IBase. */
287	pDrvIns->IBase.pfnQueryInterface = drvCharQueryInterface;
288	/* IChar. */
289	pData->IChar.pfnWrite = drvCharWrite;
290
291
292	/*
293	* Get the ICharPort interface of the above driver/device.
294	*/
295	pData->pDrvCharPort = (PPDMICHARPORT)pDrvIns->pUpBase->pfnQueryInterface(pDrvIns->pUpBase, PDMINTERFACE_CHAR_PORT);
296	if (!pData->pDrvCharPort)
297	return PDMDrvHlpVMSetError(pDrvIns, VERR_PDM_MISSING_INTERFACE_ABOVE, RT_SRC_POS, N_("Char#%d has no char port interface above"), pDrvIns->iInstance);
298
299	/*
300	* Attach driver below and query its stream interface.
301	*/
302	PPDMIBASE pBase;
303	int rc = pDrvIns->pDrvHlp->pfnAttach(pDrvIns, &pBase);
304	if (VBOX_FAILURE(rc))
305	return PDMDrvHlpVMSetError(pDrvIns, rc, RT_SRC_POS, N_("Char#%d failed to attach driver below"), pDrvIns->iInstance);
306	pData->pDrvStream = (PPDMISTREAM)pBase->pfnQueryInterface(pBase, PDMINTERFACE_STREAM);
307	if (!pData->pDrvStream)
308	return PDMDrvHlpVMSetError(pDrvIns, VERR_PDM_MISSING_INTERFACE_BELOW, RT_SRC_POS, N_("Char#%d has no stream interface below"), pDrvIns->iInstance);
309
310	rc = RTThreadCreate(&pData->ReceiveThread, drvCharReceiveLoop, (void *)pData, 0, RTTHREADTYPE_IO, RTTHREADFLAGS_WAITABLE, "Char Receive");
311	if (VBOX_FAILURE(rc))
312	return PDMDrvHlpVMSetError(pDrvIns, rc, RT_SRC_POS, N_("Char#%d cannot create receive thread"), pDrvIns->iInstance);
313
314	rc = RTSemEventCreate(&pData->SendSem);
315	AssertRC(rc);
316
317	rc = RTThreadCreate(&pData->SendThread, drvCharSendLoop, (void *)pData, 0, RTTHREADTYPE_IO, RTTHREADFLAGS_WAITABLE, "Char Send");
318	if (VBOX_FAILURE(rc))
319	return PDMDrvHlpVMSetError(pDrvIns, rc, RT_SRC_POS, N_("Char#%d cannot create send thread"), pDrvIns->iInstance);
320
321
322	PDMDrvHlpSTAMRegisterF(pDrvIns, &pData->StatBytesWritten, STAMTYPE_COUNTER, STAMVISIBILITY_USED, STAMUNIT_BYTES, "Nr of bytes written", "/Devices/Char%d/Written", pDrvIns->iInstance);
323	PDMDrvHlpSTAMRegisterF(pDrvIns, &pData->StatBytesRead, STAMTYPE_COUNTER, STAMVISIBILITY_USED, STAMUNIT_BYTES, "Nr of bytes read", "/Devices/Char%d/Read", pDrvIns->iInstance);
324
325	return VINF_SUCCESS;
326	}
327
328
329	/**
330	* Destruct a char driver instance.
331	*
332	* Most VM resources are freed by the VM. This callback is provided so that
333	* any non-VM resources can be freed correctly.
334	*
335	* @param pDrvIns The driver instance data.
336	*/
337	static DECLCALLBACK(void) drvCharDestruct(PPDMDRVINS pDrvIns)
338	{
339	PDRVCHAR pData = PDMINS2DATA(pDrvIns, PDRVCHAR);
340
341	LogFlow(("%s: iInstance=%d\n", __FUNCTION__, pDrvIns->iInstance));
342
343	pData->fShutdown = true;
344	RTThreadWait(pData->ReceiveThread, 1000, NULL);
345	if (pData->ReceiveThread != NIL_RTTHREAD)
346	LogRel(("Char%d: receive thread did not terminate\n", pDrvIns->iInstance));
347
348	/* Empty the send queue */
349	pData->iSendQueueTail = pData->iSendQueueHead = 0;
350
351	RTSemEventSignal(pData->SendSem);
352	RTSemEventDestroy(pData->SendSem);
353	pData->SendSem = NIL_RTSEMEVENT;
354
355	RTThreadWait(pData->SendThread, 1000, NULL);
356	if (pData->SendThread != NIL_RTTHREAD)
357	LogRel(("Char%d: send thread did not terminate\n", pDrvIns->iInstance));
358	}
359
360
361	/**
362	* Char driver registration record.
363	*/
364	const PDMDRVREG g_DrvChar =
365	{
366	/* u32Version */
367	PDM_DRVREG_VERSION,
368	/* szDriverName */
369	"Char",
370	/* pszDescription */
371	"Generic char driver.",
372	/* fFlags */
373	PDM_DRVREG_FLAGS_HOST_BITS_DEFAULT,
374	/* fClass. */
375	PDM_DRVREG_CLASS_CHAR,
376	/* cMaxInstances */
377	~0,
378	/* cbInstance */
379	sizeof(DRVCHAR),
380	/* pfnConstruct */
381	drvCharConstruct,
382	/* pfnDestruct */
383	drvCharDestruct,
384	/* pfnIOCtl */
385	NULL,
386	/* pfnPowerOn */
387	NULL,
388	/* pfnReset */
389	NULL,
390	/* pfnSuspend */
391	NULL,
392	/* pfnResume */
393	NULL,
394	/* pfnDetach */
395	NULL,
396	/** pfnPowerOff */
397	NULL
398	};
399

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source: vbox/trunk/src/VBox/Devices/Serial/DrvChar.cpp@ 1754

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