DBGPlugInLinux.cpp@ 61039

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1	/* $Id: DBGPlugInLinux.cpp 61039 2016-05-18 16:33:17Z vboxsync $ */
2	/** @file
3	* DBGPlugInLinux - Debugger and Guest OS Digger Plugin For Linux.
4	*/
5
6	/*
7	* Copyright (C) 2008-2015 Oracle Corporation
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*/
17
18
19	/*********************************************************************************************************************************
20	* Header Files *
21	*********************************************************************************************************************************/
22	#define LOG_GROUP LOG_GROUP_DBGF ///@todo add new log group.
23	#include "DBGPlugIns.h"
24	#include "DBGPlugInCommonELF.h"
25	#include <VBox/vmm/dbgf.h>
26	#include <iprt/string.h>
27	#include <iprt/mem.h>
28	#include <iprt/stream.h>
29	#include <iprt/ctype.h>
30
31
32	/*********************************************************************************************************************************
33	* Structures and Typedefs *
34	*********************************************************************************************************************************/
35
36	/** @name InternalLinux structures
37	* @{ */
38
39
40	/** @} */
41
42
43	/**
44	* Linux guest OS digger instance data.
45	*/
46	typedef struct DBGDIGGERLINUX
47	{
48	/** Whether the information is valid or not.
49	* (For fending off illegal interface method calls.) */
50	bool fValid;
51	/** Set if 64-bit, clear if 32-bit. */
52	bool f64Bit;
53
54	/** The address of the linux banner.
55	* This is set during probing. */
56	DBGFADDRESS AddrLinuxBanner;
57	/** Kernel base address.
58	* This is set during probing, refined during kallsyms parsing. */
59	DBGFADDRESS AddrKernelBase;
60	/** The kernel size. */
61	uint32_t cbKernel;
62
63	/** The number of kernel symbols (kallsyms_num_syms).
64	* This is set during init. */
65	uint32_t cKernelSymbols;
66	/** The size of the kernel name table (sizeof(kallsyms_names)). */
67	uint32_t cbKernelNames;
68	/** Number of entries in the kernel_markers table. */
69	uint32_t cKernelNameMarkers;
70	/** The size of the kernel symbol token table. */
71	uint32_t cbKernelTokenTable;
72	/** The address of the encoded kernel symbol names (kallsyms_names). */
73	DBGFADDRESS AddrKernelNames;
74	/** The address of the kernel symbol addresses (kallsyms_addresses). */
75	DBGFADDRESS AddrKernelAddresses;
76	/** The address of the kernel symbol name markers (kallsyms_markers). */
77	DBGFADDRESS AddrKernelNameMarkers;
78	/** The address of the kernel symbol token table (kallsyms_token_table). */
79	DBGFADDRESS AddrKernelTokenTable;
80	/** The address of the kernel symbol token index table (kallsyms_token_index). */
81	DBGFADDRESS AddrKernelTokenIndex;
82
83	/** The kernel message log interface. */
84	DBGFOSIDMESG IDmesg;
85	} DBGDIGGERLINUX;
86	/** Pointer to the linux guest OS digger instance data. */
87	typedef DBGDIGGERLINUX *PDBGDIGGERLINUX;
88
89
90	/**
91	* The current printk_log structure.
92	*/
93	typedef struct LNXPRINTKHDR
94	{
95	/** Monotonic timestamp. */
96	uint64_t nsTimestamp;
97	/** The total size of this message record. */
98	uint16_t cbTotal;
99	/** The size of the text part (immediately follows the header). */
100	uint16_t cbText;
101	/** The size of the optional dictionary part (follows the text). */
102	uint16_t cbDict;
103	/** The syslog facility number. */
104	uint8_t bFacility;
105	/** First 5 bits are internal flags, next 3 bits are log level. */
106	uint8_t fFlagsAndLevel;
107	} LNXPRINTKHDR;
108	AssertCompileSize(LNXPRINTKHDR, 2*sizeof(uint64_t));
109	/** Pointer to linux printk_log header. */
110	typedef LNXPRINTKHDR *PLNXPRINTKHDR;
111	/** Pointer to linux const printk_log header. */
112	typedef LNXPRINTKHDR const *PCLNXPRINTKHDR;
113
114
115	/*********************************************************************************************************************************
116	* Defined Constants And Macros *
117	*********************************************************************************************************************************/
118	/** Validates a 32-bit linux kernel address */
119	#define LNX32_VALID_ADDRESS(Addr) ((Addr) > UINT32_C(0x80000000) && (Addr) < UINT32_C(0xfffff000))
120	/** Validates a 64-bit linux kernel address */
121	#define LNX64_VALID_ADDRESS(Addr) ((Addr) > UINT64_C(0xffff800000000000) && (Addr) < UINT64_C(0xfffffffffffff000))
122
123	/** The max kernel size. */
124	#define LNX_MAX_KERNEL_SIZE UINT32_C(0x0f000000)
125
126	/** The maximum size we expect for kallsyms_names. */
127	#define LNX_MAX_KALLSYMS_NAMES_SIZE UINT32_C(0x200000)
128	/** The maximum size we expect for kallsyms_token_table. */
129	#define LNX_MAX_KALLSYMS_TOKEN_TABLE_SIZE UINT32_C(0x10000)
130	/** The minimum number of symbols we expect in kallsyms_num_syms. */
131	#define LNX_MIN_KALLSYMS_SYMBOLS UINT32_C(2048)
132	/** The maximum number of symbols we expect in kallsyms_num_syms. */
133	#define LNX_MAX_KALLSYMS_SYMBOLS UINT32_C(1048576)
134	/** The min length an encoded symbol in kallsyms_names is expected to have. */
135	#define LNX_MIN_KALLSYMS_ENC_LENGTH UINT8_C(1)
136	/** The max length an encoded symbol in kallsyms_names is expected to have.
137	* @todo check real life here. */
138	#define LNX_MAX_KALLSYMS_ENC_LENGTH UINT8_C(28)
139	/** The approximate maximum length of a string token. */
140	#define LNX_MAX_KALLSYMS_TOKEN_LEN UINT16_C(32)
141
142	/** Module tag for linux ('linuxmod' on little endian ASCII systems). */
143	#define DIG_LNX_MOD_TAG UINT64_C(0x545f5d78758e898c)
144
145
146	/*********************************************************************************************************************************
147	* Internal Functions *
148	*********************************************************************************************************************************/
149	static DECLCALLBACK(int) dbgDiggerLinuxInit(PUVM pUVM, void *pvData);
150
151
152	/*********************************************************************************************************************************
153	* Global Variables *
154	*********************************************************************************************************************************/
155	/** Table of common linux kernel addresses. */
156	static uint64_t g_au64LnxKernelAddresses[] =
157	{
158	UINT64_C(0xc0100000),
159	UINT64_C(0x90100000),
160	UINT64_C(0xffffffff80200000)
161	};
162
163
164	/**
165	* @interface_method_impl{DBGFOSIDMESG,pfnQueryKernelLog}
166	*/
167	static DECLCALLBACK(int) dbgDiggerLinuxIDmsg_QueryKernelLog(PDBGFOSIDMESG pThis, PUVM pUVM, uint32_t fFlags, uint32_t cMessages,
168	char pszBuf, size_t cbBuf, size_t pcbActual)
169	{
170	PDBGDIGGERLINUX pData = RT_FROM_MEMBER(pThis, DBGDIGGERLINUX, IDmesg);
171
172	if (cMessages < 1)
173	return VERR_INVALID_PARAMETER;
174
175	/*
176	* Resolve the symbols we need and read their values.
177	*/
178	RTDBGAS hAs = DBGFR3AsResolveAndRetain(pUVM, DBGF_AS_KERNEL);
179	RTDBGMOD hMod;
180	int rc = RTDbgAsModuleByName(hAs, "vmlinux", 0, &hMod);
181	if (RT_FAILURE(rc))
182	return VERR_NOT_FOUND;
183	RTDbgAsRelease(hAs);
184
185	RTGCPTR GCPtrLogBuf;
186	uint32_t cbLogBuf;
187	uint32_t idxFirst;
188	uint32_t idxNext;
189
190	struct { void pvVar; size_t cbHost, cbGuest; const char pszSymbol; } aSymbols[] =
191	{
192	{ &GCPtrLogBuf, sizeof(GCPtrLogBuf), pData->f64Bit ? sizeof(uint64_t) : sizeof(uint32_t), "log_buf" },
193	{ &cbLogBuf, sizeof(cbLogBuf), sizeof(cbLogBuf), "log_buf_len" },
194	{ &idxFirst, sizeof(idxFirst), sizeof(idxFirst), "log_first_idx" },
195	{ &idxNext, sizeof(idxNext), sizeof(idxNext), "log_next_idx" },
196	};
197	for (uint32_t i = 0; i < RT_ELEMENTS(aSymbols); i++)
198	{
199	RTDBGSYMBOL SymInfo;
200	rc = RTDbgModSymbolByName(hMod, aSymbols[i].pszSymbol, &SymInfo);
201	if (RT_SUCCESS(rc))
202	{
203	RT_BZERO(aSymbols[i].pvVar, aSymbols[i].cbHost);
204	Assert(aSymbols[i].cbHost >= aSymbols[i].cbGuest);
205	DBGFADDRESS Addr;
206	rc = DBGFR3MemRead(pUVM, 0 /idCpu/,
207	DBGFR3AddrFromFlat(pUVM, &Addr, (RTGCPTR)SymInfo.Value + pData->AddrKernelBase.FlatPtr),
208	aSymbols[i].pvVar, aSymbols[i].cbGuest);
209	if (RT_SUCCESS(rc))
210	continue;
211	Log(("dbgDiggerLinuxIDmsg_QueryKernelLog: Reading '%s' at %RGv: %Rrc\n", aSymbols[i].pszSymbol, Addr.FlatPtr, rc));
212	}
213	else
214	Log(("dbgDiggerLinuxIDmsg_QueryKernelLog: Error looking up '%s': %Rrc\n", aSymbols[i].pszSymbol, rc));
215	RTDbgModRelease(hMod);
216	return VERR_NOT_FOUND;
217	}
218
219	/*
220	* Check if the values make sense.
221	*/
222	if (pData->f64Bit ? !LNX64_VALID_ADDRESS(GCPtrLogBuf) : !LNX32_VALID_ADDRESS(GCPtrLogBuf))
223	{
224	Log(("dbgDiggerLinuxIDmsg_QueryKernelLog: 'log_buf' value %RGv is not valid.\n", GCPtrLogBuf));
225	return VERR_NOT_FOUND;
226	}
227	if ( cbLogBuf < 4096
228	\|\| !RT_IS_POWER_OF_TWO(cbLogBuf)
229	\|\| cbLogBuf > 16*_1M)
230	{
231	Log(("dbgDiggerLinuxIDmsg_QueryKernelLog: 'log_buf_len' value %#x is not valid.\n", cbLogBuf));
232	return VERR_NOT_FOUND;
233	}
234	uint32_t const cbLogAlign = 4;
235	if ( idxFirst > cbLogBuf - sizeof(LNXPRINTKHDR)
236	\|\| (idxFirst & (cbLogAlign - 1)) != 0)
237	{
238	Log(("dbgDiggerLinuxIDmsg_QueryKernelLog: 'log_first_idx' value %#x is not valid.\n", idxFirst));
239	return VERR_NOT_FOUND;
240	}
241	if ( idxNext > cbLogBuf - sizeof(LNXPRINTKHDR)
242	\|\| (idxNext & (cbLogAlign - 1)) != 0)
243	{
244	Log(("dbgDiggerLinuxIDmsg_QueryKernelLog: 'log_next_idx' value %#x is not valid.\n", idxNext));
245	return VERR_NOT_FOUND;
246	}
247
248	/*
249	* Read the whole log buffer.
250	*/
251	uint8_t pbLogBuf = (uint8_t )RTMemAlloc(cbLogBuf);
252	if (!pbLogBuf)
253	{
254	Log(("dbgDiggerLinuxIDmsg_QueryKernelLog: Failed to allocate %#x bytes for log buffer\n", cbLogBuf));
255	return VERR_NO_MEMORY;
256	}
257	DBGFADDRESS Addr;
258	rc = DBGFR3MemRead(pUVM, 0 /idCpu/, DBGFR3AddrFromFlat(pUVM, &Addr, GCPtrLogBuf), pbLogBuf, cbLogBuf);
259	if (RT_FAILURE(rc))
260	{
261	Log(("dbgDiggerLinuxIDmsg_QueryKernelLog: Error reading %#x bytes of log buffer at %RGv: %Rrc\n",
262	cbLogBuf, Addr.FlatPtr, rc));
263	RTMemFree(pbLogBuf);
264	return VERR_NOT_FOUND;
265	}
266
267	/*
268	* Count the messages in the buffer while doing some basic validation.
269	*/
270	uint32_t const cbUsed = idxFirst == idxNext ? cbLogBuf /* could be empty... */
271	: idxFirst < idxNext ? idxNext - idxFirst : cbLogBuf - idxFirst + idxNext;
272	uint32_t cbLeft = cbUsed;
273	uint32_t offCur = idxFirst;
274	uint32_t cLogMsgs = 0;
275
276	while (cbLeft > 0)
277	{
278	PCLNXPRINTKHDR pHdr = (PCLNXPRINTKHDR)&pbLogBuf[offCur];
279	if (!pHdr->cbTotal)
280	{
281	/* Wrap around packet, most likely... */
282	if (cbLogBuf - offCur >= cbLeft)
283	break;
284	offCur = 0;
285	pHdr = (PCLNXPRINTKHDR)&pbLogBuf[offCur];
286	}
287	if (RT_UNLIKELY( pHdr->cbTotal > cbLogBuf - sizeof(*pHdr) - offCur
288	\|\| pHdr->cbTotal > cbLeft
289	\|\| (pHdr->cbTotal & (cbLogAlign - 1)) != 0
290	\|\| pHdr->cbTotal < (uint32_t)pHdr->cbText + (uint32_t)pHdr->cbDict + sizeof(*pHdr) ))
291	{
292	Log(("dbgDiggerLinuxIDmsg_QueryKernelLog: Invalid printk_log record at %#x: cbTotal=%#x cbText=%#x cbDict=%#x cbLogBuf=%#x cbLeft=%#x\n",
293	offCur, pHdr->cbTotal, pHdr->cbText, pHdr->cbDict, cbLogBuf, cbLeft));
294	rc = VERR_INVALID_STATE;
295	break;
296	}
297
298	if (pHdr->cbText > 0)
299	cLogMsgs++;
300
301	/* next */
302	offCur += pHdr->cbTotal;
303	cbLeft -= pHdr->cbTotal;
304	}
305	if (RT_FAILURE(rc))
306	{
307	RTMemFree(pbLogBuf);
308	return rc;
309	}
310
311	/*
312	* Copy the messages into the output buffer.
313	*/
314	offCur = idxFirst;
315	cbLeft = cbUsed;
316
317	/* Skip messages that the caller doesn't want. */
318	if (cMessages < cLogMsgs)
319	{
320	uint32_t cToSkip = cLogMsgs - cMessages;
321	while (cToSkip > 0)
322	{
323	PCLNXPRINTKHDR pHdr = (PCLNXPRINTKHDR)&pbLogBuf[offCur];
324	if (!pHdr->cbTotal)
325	{
326	offCur = 0;
327	pHdr = (PCLNXPRINTKHDR)&pbLogBuf[offCur];
328	}
329	if (pHdr->cbText > 0)
330	cToSkip--;
331
332	/* next */
333	offCur += pHdr->cbTotal;
334	cbLeft -= pHdr->cbTotal;
335	}
336	}
337
338	/* Now copy the messages. */
339	size_t offDst = 0;
340	while (cbLeft > 0)
341	{
342	PCLNXPRINTKHDR pHdr = (PCLNXPRINTKHDR)&pbLogBuf[offCur];
343	if (!pHdr->cbTotal)
344	{
345	if (cbLogBuf - offCur >= cbLeft)
346	break;
347	offCur = 0;
348	pHdr = (PCLNXPRINTKHDR)&pbLogBuf[offCur];
349	}
350
351	if (pHdr->cbText > 0)
352	{
353	char pchText = (char )(pHdr + 1);
354	size_t cchText = RTStrNLen(pchText, pHdr->cbText);
355	if (offDst + cchText < cbBuf)
356	{
357	memcpy(&pszBuf[offDst], pHdr + 1, cchText);
358	pszBuf[offDst + cchText] = '\n';
359	}
360	else if (offDst < cbBuf)
361	memcpy(&pszBuf[offDst], pHdr + 1, cbBuf - offDst);
362	offDst += cchText + 1;
363	}
364
365	/* next */
366	offCur += pHdr->cbTotal;
367	cbLeft -= pHdr->cbTotal;
368	}
369
370	/* Done with the buffer. */
371	RTMemFree(pbLogBuf);
372
373	/* Make sure we've reserved a char for the terminator. */
374	if (!offDst)
375	offDst = 1;
376
377	/* Set return size value. */
378	if (pcbActual)
379	*pcbActual = offDst;
380
381	/*
382	* All VBox strings are UTF-8 and bad things may in theory happen if we
383	* pass bad UTF-8 to code which assumes it's all valid. So, we enforce
384	* UTF-8 upon the guest kernel messages here even if they (probably) have
385	* no defined code set in reality.
386	*/
387	if (offDst <= cbBuf)
388	{
389	pszBuf[offDst - 1] = '\0';
390	RTStrPurgeEncoding(pszBuf);
391	return VINF_SUCCESS;
392	}
393
394	if (cbBuf)
395	{
396	pszBuf[cbBuf - 1] = '\0';
397	RTStrPurgeEncoding(pszBuf);
398	}
399	return VERR_BUFFER_OVERFLOW;
400	}
401
402
403	/**
404	* @copydoc DBGFOSREG::pfnQueryInterface
405	*/
406	static DECLCALLBACK(void ) dbgDiggerLinuxQueryInterface(PUVM pUVM, void pvData, DBGFOSINTERFACE enmIf)
407	{
408	PDBGDIGGERLINUX pThis = (PDBGDIGGERLINUX)pvData;
409	switch (enmIf)
410	{
411	case DBGFOSINTERFACE_DMESG:
412	return &pThis->IDmesg;
413
414	default:
415	return NULL;
416	}
417	}
418
419
420	/**
421	* @copydoc DBGFOSREG::pfnQueryVersion
422	*/
423	static DECLCALLBACK(int) dbgDiggerLinuxQueryVersion(PUVM pUVM, void pvData, char pszVersion, size_t cchVersion)
424	{
425	PDBGDIGGERLINUX pThis = (PDBGDIGGERLINUX)pvData;
426	Assert(pThis->fValid);
427
428	/*
429	* It's all in the linux banner.
430	*/
431	int rc = DBGFR3MemReadString(pUVM, 0, &pThis->AddrLinuxBanner, pszVersion, cchVersion);
432	if (RT_SUCCESS(rc))
433	{
434	char *pszEnd = RTStrEnd(pszVersion, cchVersion);
435	AssertReturn(pszEnd, VERR_BUFFER_OVERFLOW);
436	while ( pszEnd > pszVersion
437	&& RT_C_IS_SPACE(pszEnd[-1]))
438	pszEnd--;
439	*pszEnd = '\0';
440	}
441	else
442	RTStrPrintf(pszVersion, cchVersion, "DBGFR3MemRead -> %Rrc", rc);
443
444	return rc;
445	}
446
447
448	/**
449	* @copydoc DBGFOSREG::pfnTerm
450	*/
451	static DECLCALLBACK(void) dbgDiggerLinuxTerm(PUVM pUVM, void *pvData)
452	{
453	PDBGDIGGERLINUX pThis = (PDBGDIGGERLINUX)pvData;
454	Assert(pThis->fValid);
455
456	pThis->fValid = false;
457	}
458
459
460	/**
461	* @copydoc DBGFOSREG::pfnRefresh
462	*/
463	static DECLCALLBACK(int) dbgDiggerLinuxRefresh(PUVM pUVM, void *pvData)
464	{
465	PDBGDIGGERLINUX pThis = (PDBGDIGGERLINUX)pvData;
466	NOREF(pThis);
467	Assert(pThis->fValid);
468
469	/*
470	* For now we'll flush and reload everything.
471	*/
472	dbgDiggerLinuxTerm(pUVM, pvData);
473	return dbgDiggerLinuxInit(pUVM, pvData);
474	}
475
476
477	/**
478	* Worker for dbgDiggerLinuxFindStartOfNamesAndSymbolCount that update the
479	* digger data.
480	*
481	* @returns VINF_SUCCESS.
482	* @param pThis The Linux digger data to update.
483	* @param pAddrKernelNames The kallsyms_names address.
484	* @param cKernelSymbols The number of kernel symbol.
485	* @param cbAddress The guest address size.
486	*/
487	static int dbgDiggerLinuxFoundStartOfNames(PDBGDIGGERLINUX pThis, PCDBGFADDRESS pAddrKernelNames,
488	uint32_t cKernelSymbols, uint32_t cbAddress)
489	{
490	pThis->cKernelSymbols = cKernelSymbols;
491	pThis->AddrKernelNames = *pAddrKernelNames;
492	pThis->AddrKernelAddresses = *pAddrKernelNames;
493	DBGFR3AddrSub(&pThis->AddrKernelAddresses, (cKernelSymbols + 1) * cbAddress);
494
495	Log(("dbgDiggerLinuxFoundStartOfNames: AddrKernelAddresses=%RGv\n"
496	"dbgDiggerLinuxFoundStartOfNames: cKernelSymbols=%#x (at %RGv)\n"
497	"dbgDiggerLinuxFoundStartOfNames: AddrKernelName=%RGv\n",
498	pThis->AddrKernelAddresses.FlatPtr,
499	pThis->cKernelSymbols, pThis->AddrKernelNames.FlatPtr - cbAddress,
500	pThis->AddrKernelNames.FlatPtr));
501	return VINF_SUCCESS;
502	}
503
504
505	/**
506	* Tries to find the address of the kallsyms_names, kallsyms_num_syms and
507	* kallsyms_addresses symbols.
508	*
509	* The kallsyms_num_syms is read and stored in pThis->cKernelSymbols, while the
510	* addresses of the other two are stored as pThis->AddrKernelNames and
511	* pThis->AddrKernelAddresses.
512	*
513	* @returns VBox status code, success indicating that all three variables have
514	* been found and taken down.
515	* @param pUVM The user mode VM handle.
516	* @param pThis The Linux digger data.
517	* @param pHitAddr An address we think is inside kallsyms_names.
518	*/
519	static int dbgDiggerLinuxFindStartOfNamesAndSymbolCount(PUVM pUVM, PDBGDIGGERLINUX pThis, PCDBGFADDRESS pHitAddr)
520	{
521	/*
522	* Search backwards in chunks.
523	*/
524	union
525	{
526	uint8_t ab[0x1000];
527	uint32_t au32[0x1000 / sizeof(uint32_t)];
528	uint64_t au64[0x1000 / sizeof(uint64_t)];
529	} uBuf;
530	uint32_t cbLeft = LNX_MAX_KALLSYMS_NAMES_SIZE;
531	uint32_t cbBuf = pHitAddr->FlatPtr & (sizeof(uBuf) - 1);
532	DBGFADDRESS CurAddr = *pHitAddr;
533	DBGFR3AddrSub(&CurAddr, cbBuf);
534	cbBuf += sizeof(uint64_t) - 1; /* In case our kobj hit is in the first 4/8 bytes. */
535	for (;;)
536	{
537	int rc = DBGFR3MemRead(pUVM, 0 /idCpu/, &CurAddr, &uBuf, sizeof(uBuf));
538	if (RT_FAILURE(rc))
539	return rc;
540
541	/*
542	* We assume that the three symbols are aligned on guest pointer boundrary.
543	*
544	* The boundrary between the two tables should be noticable as the number
545	* is unlikely to be more than 16 millions, there will be at least one zero
546	* byte where it is, 64-bit will have 5 zero bytes. Zero bytes aren't all
547	* that common in the kallsyms_names table.
548	*
549	* Also the kallsyms_names table starts with a length byte, which means
550	* we're likely to see a byte in the range 1..31.
551	*
552	* The kallsyms_addresses are mostly sorted (except for the start where the
553	* absolute symbols are), so we'll spot a bunch of kernel addresses
554	* immediately preceeding the kallsyms_num_syms field.
555	*
556	* Lazy bird: If kallsyms_num_syms is on a buffer boundrary, we skip
557	* the check for kernel addresses preceeding it.
558	*/
559	if (pThis->f64Bit)
560	{
561	uint32_t i = cbBuf / sizeof(uint64_t);
562	while (i-- > 0)
563	if ( uBuf.au64[i] <= LNX_MAX_KALLSYMS_SYMBOLS
564	&& uBuf.au64[i] >= LNX_MIN_KALLSYMS_SYMBOLS)
565	{
566	uint8_t pb = (uint8_t )&uBuf.au64[i + 1];
567	if ( pb[0] <= LNX_MAX_KALLSYMS_ENC_LENGTH
568	&& pb[0] >= LNX_MIN_KALLSYMS_ENC_LENGTH)
569	{
570	if ( (i <= 0 \|\| LNX64_VALID_ADDRESS(uBuf.au64[i - 1]))
571	&& (i <= 1 \|\| LNX64_VALID_ADDRESS(uBuf.au64[i - 2]))
572	&& (i <= 2 \|\| LNX64_VALID_ADDRESS(uBuf.au64[i - 3])))
573	return dbgDiggerLinuxFoundStartOfNames(pThis,
574	DBGFR3AddrAdd(&CurAddr, (i + 1) * sizeof(uint64_t)),
575	(uint32_t)uBuf.au64[i], sizeof(uint64_t));
576	}
577	}
578	}
579	else
580	{
581	uint32_t i = cbBuf / sizeof(uint32_t);
582	while (i-- > 0)
583	if ( uBuf.au32[i] <= LNX_MAX_KALLSYMS_SYMBOLS
584	&& uBuf.au32[i] >= LNX_MIN_KALLSYMS_SYMBOLS)
585	{
586	uint8_t pb = (uint8_t )&uBuf.au32[i + 1];
587	if ( pb[0] <= LNX_MAX_KALLSYMS_ENC_LENGTH
588	&& pb[0] >= LNX_MIN_KALLSYMS_ENC_LENGTH)
589	{
590	if ( (i <= 0 \|\| LNX32_VALID_ADDRESS(uBuf.au32[i - 1]))
591	&& (i <= 1 \|\| LNX32_VALID_ADDRESS(uBuf.au32[i - 2]))
592	&& (i <= 2 \|\| LNX32_VALID_ADDRESS(uBuf.au32[i - 3])))
593	return dbgDiggerLinuxFoundStartOfNames(pThis,
594	DBGFR3AddrAdd(&CurAddr, (i + 1) * sizeof(uint32_t)),
595	uBuf.au32[i], sizeof(uint32_t));
596	}
597	}
598	}
599
600	/*
601	* Advance
602	*/
603	if (RT_UNLIKELY(cbLeft <= sizeof(uBuf)))
604	{
605	Log(("dbgDiggerLinuxFindStartOfNamesAndSymbolCount: failed (pHitAddr=%RGv)\n", pHitAddr->FlatPtr));
606	return VERR_NOT_FOUND;
607	}
608	cbLeft -= sizeof(uBuf);
609	DBGFR3AddrSub(&CurAddr, sizeof(uBuf));
610	cbBuf = sizeof(uBuf);
611	}
612	}
613
614
615	/**
616	* Worker for dbgDiggerLinuxFindEndNames that records the findings.
617	*
618	* @returns VINF_SUCCESS
619	* @param pThis The linux digger data to update.
620	* @param pAddrMarkers The address of the marker (kallsyms_markers).
621	* @param cbMarkerEntry The size of a marker entry (32-bit or 64-bit).
622	*/
623	static int dbgDiggerLinuxFoundMarkers(PDBGDIGGERLINUX pThis, PCDBGFADDRESS pAddrMarkers, uint32_t cbMarkerEntry)
624	{
625	pThis->cbKernelNames = pAddrMarkers->FlatPtr - pThis->AddrKernelNames.FlatPtr - 1;
626	pThis->AddrKernelNameMarkers = *pAddrMarkers;
627	pThis->cKernelNameMarkers = RT_ALIGN_32(pThis->cKernelSymbols, 256) / 256;
628	pThis->AddrKernelTokenTable = *pAddrMarkers;
629	DBGFR3AddrAdd(&pThis->AddrKernelTokenTable, pThis->cKernelNameMarkers * cbMarkerEntry);
630
631	Log(("dbgDiggerLinuxFoundMarkers: AddrKernelNames=%RGv cbKernelNames=%#x\n"
632	"dbgDiggerLinuxFoundMarkers: AddrKernelNameMarkers=%RGv cKernelNameMarkers=%#x\n"
633	"dbgDiggerLinuxFoundMarkers: AddrKernelTokenTable=%RGv\n",
634	pThis->AddrKernelNames.FlatPtr, pThis->cbKernelNames,
635	pThis->AddrKernelNameMarkers.FlatPtr, pThis->cKernelNameMarkers,
636	pThis->AddrKernelTokenTable.FlatPtr));
637	return VINF_SUCCESS;
638	}
639
640
641	/**
642	* Tries to find the end of kallsyms_names and thereby the start of
643	* kallsyms_markers and kallsyms_token_table.
644	*
645	* The kallsyms_names size is stored in pThis->cbKernelNames, the addresses of
646	* the two other symbols in pThis->AddrKernelNameMarkers and
647	* pThis->AddrKernelTokenTable. The number of marker entries is stored in
648	* pThis->cKernelNameMarkers.
649	*
650	* @returns VBox status code, success indicating that all three variables have
651	* been found and taken down.
652	* @param pUVM The user mode VM handle.
653	* @param pThis The Linux digger data.
654	* @param pHitAddr An address we think is inside kallsyms_names.
655	*/
656	static int dbgDiggerLinuxFindEndOfNamesAndMore(PUVM pUVM, PDBGDIGGERLINUX pThis, PCDBGFADDRESS pHitAddr)
657	{
658	/*
659	* Search forward in chunks.
660	*/
661	union
662	{
663	uint8_t ab[0x1000];
664	uint32_t au32[0x1000 / sizeof(uint32_t)];
665	uint64_t au64[0x1000 / sizeof(uint64_t)];
666	} uBuf;
667	bool fPendingZeroHit = false;
668	uint32_t cbLeft = LNX_MAX_KALLSYMS_NAMES_SIZE + sizeof(uBuf);
669	uint32_t offBuf = pHitAddr->FlatPtr & (sizeof(uBuf) - 1);
670	DBGFADDRESS CurAddr = *pHitAddr;
671	DBGFR3AddrSub(&CurAddr, offBuf);
672	for (;;)
673	{
674	int rc = DBGFR3MemRead(pUVM, 0 /idCpu/, &CurAddr, &uBuf, sizeof(uBuf));
675	if (RT_FAILURE(rc))
676	return rc;
677
678	/*
679	* The kallsyms_names table is followed by kallsyms_markers we assume,
680	* using sizeof(unsigned long) alignment like the preceeding symbols.
681	*
682	* The kallsyms_markers table has entried sizeof(unsigned long) and
683	* contains offsets into kallsyms_names. The kallsyms_markers used to
684	* index kallsyms_names and reduce seek time when looking up the name
685	* of an address/symbol. Each entry in kallsyms_markers covers 256
686	* symbol names.
687	*
688	* Because of this, the first entry is always zero and all the entries
689	* are ascending. It also follows that the size of the table can be
690	* calculated from kallsyms_num_syms.
691	*
692	* Note! We could also have walked kallsyms_names by skipping
693	* kallsyms_num_syms names, but this is faster and we will
694	* validate the encoded names later.
695	*/
696	if (pThis->f64Bit)
697	{
698	if ( RT_UNLIKELY(fPendingZeroHit)
699	&& uBuf.au64[0] >= (LNX_MIN_KALLSYMS_ENC_LENGTH + 1) * 256
700	&& uBuf.au64[0] <= (LNX_MAX_KALLSYMS_ENC_LENGTH + 1) * 256)
701	return dbgDiggerLinuxFoundMarkers(pThis, DBGFR3AddrSub(&CurAddr, sizeof(uint64_t)), sizeof(uint64_t));
702
703	uint32_t const cEntries = sizeof(uBuf) / sizeof(uint64_t);
704	for (uint32_t i = offBuf / sizeof(uint64_t); i < cEntries; i++)
705	if (uBuf.au64[i] == 0)
706	{
707	if (RT_UNLIKELY(i + 1 >= cEntries))
708	{
709	fPendingZeroHit = true;
710	break;
711	}
712	if ( uBuf.au64[i + 1] >= (LNX_MIN_KALLSYMS_ENC_LENGTH + 1) * 256
713	&& uBuf.au64[i + 1] <= (LNX_MAX_KALLSYMS_ENC_LENGTH + 1) * 256)
714	return dbgDiggerLinuxFoundMarkers(pThis, DBGFR3AddrAdd(&CurAddr, i * sizeof(uint64_t)), sizeof(uint64_t));
715	}
716	}
717	else
718	{
719	if ( RT_UNLIKELY(fPendingZeroHit)
720	&& uBuf.au32[0] >= (LNX_MIN_KALLSYMS_ENC_LENGTH + 1) * 256
721	&& uBuf.au32[0] <= (LNX_MAX_KALLSYMS_ENC_LENGTH + 1) * 256)
722	return dbgDiggerLinuxFoundMarkers(pThis, DBGFR3AddrSub(&CurAddr, sizeof(uint32_t)), sizeof(uint32_t));
723
724	uint32_t const cEntries = sizeof(uBuf) / sizeof(uint32_t);
725	for (uint32_t i = offBuf / sizeof(uint32_t); i < cEntries; i++)
726	if (uBuf.au32[i] == 0)
727	{
728	if (RT_UNLIKELY(i + 1 >= cEntries))
729	{
730	fPendingZeroHit = true;
731	break;
732	}
733	if ( uBuf.au32[i + 1] >= (LNX_MIN_KALLSYMS_ENC_LENGTH + 1) * 256
734	&& uBuf.au32[i + 1] <= (LNX_MAX_KALLSYMS_ENC_LENGTH + 1) * 256)
735	return dbgDiggerLinuxFoundMarkers(pThis, DBGFR3AddrAdd(&CurAddr, i * sizeof(uint32_t)), sizeof(uint32_t));
736	}
737	}
738
739	/*
740	* Advance
741	*/
742	if (RT_UNLIKELY(cbLeft <= sizeof(uBuf)))
743	{
744	Log(("dbgDiggerLinuxFindEndOfNamesAndMore: failed (pHitAddr=%RGv)\n", pHitAddr->FlatPtr));
745	return VERR_NOT_FOUND;
746	}
747	cbLeft -= sizeof(uBuf);
748	DBGFR3AddrAdd(&CurAddr, sizeof(uBuf));
749	offBuf = 0;
750	}
751	}
752
753
754	/**
755	* Locates the kallsyms_token_index table.
756	*
757	* Storing the address in pThis->AddrKernelTokenIndex and the size of the token
758	* table in pThis->cbKernelTokenTable.
759	*
760	* @returns VBox status code.
761	* @param pUVM The user mode VM handle.
762	* @param pThis The Linux digger data.
763	*/
764	static int dbgDiggerLinuxFindTokenIndex(PUVM pUVM, PDBGDIGGERLINUX pThis)
765	{
766	/*
767	* The kallsyms_token_table is very much like a string table. Due to the
768	* nature of the compression algorithm it is reasonably short (one example
769	* here is 853 bytes), so we'll not be reading it in chunks but in full.
770	* To be on the safe side, we read 8KB, ASSUMING we won't run into unmapped
771	* memory or any other nasty stuff...
772	*/
773	union
774	{
775	uint8_t ab[0x2000];
776	uint16_t au16[0x2000 / sizeof(uint16_t)];
777	} uBuf;
778	DBGFADDRESS CurAddr = pThis->AddrKernelTokenTable;
779	int rc = DBGFR3MemRead(pUVM, 0 /idCpu/, &CurAddr, &uBuf, sizeof(uBuf));
780	if (RT_FAILURE(rc))
781	return rc;
782
783	/*
784	* We've got two choices here, either walk the string table or look for
785	* the next structure, kallsyms_token_index.
786	*
787	* The token index is a table of 256 uint16_t entries (index by bytes
788	* from kallsyms_names) that gives offsets in kallsyms_token_table. It
789	* starts with a zero entry and the following entries are sorted in
790	* ascending order. The range of the entries are reasonably small since
791	* kallsyms_token_table is small.
792	*
793	* The alignment seems to be sizeof(unsigned long), just like
794	* kallsyms_token_table.
795	*
796	* So, we start by looking for a zero 16-bit entry.
797	*/
798	uint32_t cIncr = (pThis->f64Bit ? sizeof(uint64_t) : sizeof(uint32_t)) / sizeof(uint16_t);
799
800	for (uint32_t i = 0; i < sizeof(uBuf) / sizeof(uint16_t) - 16; i += cIncr)
801	if ( uBuf.au16[i] == 0
802	&& uBuf.au16[i + 1] > 0
803	&& uBuf.au16[i + 1] <= LNX_MAX_KALLSYMS_TOKEN_LEN
804	&& (uint16_t)(uBuf.au16[i + 2] - uBuf.au16[i + 1] - 1U) <= (uint16_t)LNX_MAX_KALLSYMS_TOKEN_LEN
805	&& (uint16_t)(uBuf.au16[i + 3] - uBuf.au16[i + 2] - 1U) <= (uint16_t)LNX_MAX_KALLSYMS_TOKEN_LEN
806	&& (uint16_t)(uBuf.au16[i + 4] - uBuf.au16[i + 3] - 1U) <= (uint16_t)LNX_MAX_KALLSYMS_TOKEN_LEN
807	&& (uint16_t)(uBuf.au16[i + 5] - uBuf.au16[i + 4] - 1U) <= (uint16_t)LNX_MAX_KALLSYMS_TOKEN_LEN
808	&& (uint16_t)(uBuf.au16[i + 6] - uBuf.au16[i + 5] - 1U) <= (uint16_t)LNX_MAX_KALLSYMS_TOKEN_LEN
809	)
810	{
811	pThis->AddrKernelTokenIndex = CurAddr;
812	DBGFR3AddrAdd(&pThis->AddrKernelTokenIndex, i * sizeof(uint16_t));
813	pThis->cbKernelTokenTable = i * sizeof(uint16_t);
814	return VINF_SUCCESS;
815	}
816
817	Log(("dbgDiggerLinuxFindTokenIndex: Failed (%RGv..%RGv)\n", CurAddr.FlatPtr, CurAddr.FlatPtr + (RTGCUINTPTR)sizeof(uBuf)));
818	return VERR_NOT_FOUND;
819	}
820
821
822	/**
823	* Loads the kernel symbols from the kallsyms tables.
824	*
825	* @returns VBox status code.
826	* @param pUVM The user mode VM handle.
827	* @param pThis The Linux digger data.
828	*/
829	static int dbgDiggerLinuxLoadKernelSymbols(PUVM pUVM, PDBGDIGGERLINUX pThis)
830	{
831	/*
832	* Allocate memory for temporary table copies, reading the tables as we go.
833	*/
834	uint32_t const cbGuestAddr = pThis->f64Bit ? sizeof(uint64_t) : sizeof(uint32_t);
835	void pvAddresses = RTMemAllocZ(pThis->cKernelSymbols cbGuestAddr);
836	int rc = DBGFR3MemRead(pUVM, 0 /idCpu/, &pThis->AddrKernelAddresses, pvAddresses, pThis->cKernelSymbols * cbGuestAddr);
837	if (RT_SUCCESS(rc))
838	{
839	uint8_t pbNames = (uint8_t )RTMemAllocZ(pThis->cbKernelNames);
840	rc = DBGFR3MemRead(pUVM, 0 /idCpu/, &pThis->AddrKernelNames, pbNames, pThis->cbKernelNames);
841	if (RT_SUCCESS(rc))
842	{
843	char pszzTokens = (char )RTMemAllocZ(pThis->cbKernelTokenTable);
844	rc = DBGFR3MemRead(pUVM, 0 /idCpu/, &pThis->AddrKernelTokenTable, pszzTokens, pThis->cbKernelTokenTable);
845	if (RT_SUCCESS(rc))
846	{
847	uint16_t paoffTokens = (uint16_t )RTMemAllocZ(256 * sizeof(uint16_t));
848	rc = DBGFR3MemRead(pUVM, 0 /idCpu/, &pThis->AddrKernelTokenIndex, paoffTokens, 256 * sizeof(uint16_t));
849	if (RT_SUCCESS(rc))
850	{
851	/*
852	* Figure out the kernel start and end.
853	*/
854	RTGCUINTPTR uKernelStart = pThis->AddrKernelAddresses.FlatPtr;
855	RTGCUINTPTR uKernelEnd = pThis->AddrKernelTokenIndex.FlatPtr + 256 * sizeof(uint16_t);
856	uint32_t i;
857	if (cbGuestAddr == sizeof(uint64_t))
858	{
859	uint64_t pauAddrs = (uint64_t )pvAddresses;
860	for (i = 0; i < pThis->cKernelSymbols; i++)
861	if ( pauAddrs[i] < uKernelStart
862	&& LNX64_VALID_ADDRESS(pauAddrs[i])
863	&& uKernelStart - pauAddrs[i] < LNX_MAX_KERNEL_SIZE)
864	uKernelStart = pauAddrs[i];
865
866	for (i = pThis->cKernelSymbols - 1; i > 0; i--)
867	if ( pauAddrs[i] > uKernelEnd
868	&& LNX64_VALID_ADDRESS(pauAddrs[i])
869	&& pauAddrs[i] - uKernelEnd < LNX_MAX_KERNEL_SIZE)
870	uKernelEnd = pauAddrs[i];
871	}
872	else
873	{
874	uint32_t pauAddrs = (uint32_t )pvAddresses;
875	for (i = 0; i < pThis->cKernelSymbols; i++)
876	if ( pauAddrs[i] < uKernelStart
877	&& LNX32_VALID_ADDRESS(pauAddrs[i])
878	&& uKernelStart - pauAddrs[i] < LNX_MAX_KERNEL_SIZE)
879	uKernelStart = pauAddrs[i];
880
881	for (i = pThis->cKernelSymbols - 1; i > 0; i--)
882	if ( pauAddrs[i] > uKernelEnd
883	&& LNX32_VALID_ADDRESS(pauAddrs[i])
884	&& pauAddrs[i] - uKernelEnd < LNX_MAX_KERNEL_SIZE)
885	uKernelEnd = pauAddrs[i];
886	}
887
888	RTGCUINTPTR cbKernel = uKernelEnd - uKernelStart;
889	pThis->cbKernel = (uint32_t)cbKernel;
890	DBGFR3AddrFromFlat(pUVM, &pThis->AddrKernelBase, uKernelStart);
891	Log(("dbgDiggerLinuxLoadKernelSymbols: uKernelStart=%RGv cbKernel=%#x\n", uKernelStart, cbKernel));
892
893	/*
894	* Create a module for the kernel.
895	*/
896	RTDBGMOD hMod;
897	rc = RTDbgModCreate(&hMod, "vmlinux", cbKernel, 0 /fFlags/);
898	if (RT_SUCCESS(rc))
899	{
900	rc = RTDbgModSetTag(hMod, DIG_LNX_MOD_TAG); AssertRC(rc);
901	rc = VINF_SUCCESS;
902
903	/*
904	* Enumerate the symbols.
905	*/
906	uint8_t const pbCurAddr = (uint8_t const )pvAddresses;
907	uint32_t offName = 0;
908	uint32_t cLeft = pThis->cKernelSymbols;
909	while (cLeft-- > 0 && RT_SUCCESS(rc))
910	{
911	/* Decode the symbol name first. */
912	if (RT_LIKELY(offName < pThis->cbKernelNames))
913	{
914	uint8_t cbName = pbNames[offName++];
915	if (RT_LIKELY(offName + cbName <= pThis->cbKernelNames))
916	{
917	char szSymbol[4096];
918	uint32_t offSymbol = 0;
919	while (cbName-- > 0)
920	{
921	uint8_t bEnc = pbNames[offName++];
922	uint16_t offToken = paoffTokens[bEnc];
923	if (RT_LIKELY(offToken < pThis->cbKernelTokenTable))
924	{
925	const char *pszToken = &pszzTokens[offToken];
926	char ch;
927	while ((ch = *pszToken++) != '\0')
928	if (offSymbol < sizeof(szSymbol) - 1)
929	szSymbol[offSymbol++] = ch;
930	}
931	else
932	{
933	rc = VERR_INVALID_UTF8_ENCODING;
934	break;
935	}
936	}
937	szSymbol[offSymbol < sizeof(szSymbol) ? offSymbol : sizeof(szSymbol) - 1] = '\0';
938
939	/* The address. */
940	RTGCUINTPTR uSymAddr = cbGuestAddr == sizeof(uint64_t)
941	? (uint64_t )pbCurAddr : (uint32_t )pbCurAddr;
942	pbCurAddr += cbGuestAddr;
943
944	/* Add it without the type char. */
945	if (uSymAddr - uKernelStart <= cbKernel)
946	{
947	rc = RTDbgModSymbolAdd(hMod, &szSymbol[1], RTDBGSEGIDX_RVA, uSymAddr - uKernelStart,
948	0 /cb/, 0 /fFlags/, NULL);
949	if (RT_FAILURE(rc))
950	{
951	if ( rc == VERR_DBG_SYMBOL_NAME_OUT_OF_RANGE
952	\|\| rc == VERR_DBG_INVALID_RVA
953	\|\| rc == VERR_DBG_ADDRESS_CONFLICT
954	\|\| rc == VERR_DBG_DUPLICATE_SYMBOL)
955	{
956	Log2(("dbgDiggerLinuxLoadKernelSymbols: RTDbgModSymbolAdd(,%s,) failed %Rrc (ignored)\n", szSymbol, rc));
957	rc = VINF_SUCCESS;
958	}
959	else
960	Log(("dbgDiggerLinuxLoadKernelSymbols: RTDbgModSymbolAdd(,%s,) failed %Rrc\n", szSymbol, rc));
961	}
962	}
963	}
964	else
965	{
966	rc = VERR_END_OF_STRING;
967	Log(("dbgDiggerLinuxLoadKernelSymbols: offName=%#x cLeft=%#x cbName=%#x cbKernelNames=%#x\n",
968	offName, cLeft, cbName, pThis->cbKernelNames));
969	}
970	}
971	else
972	{
973	rc = VERR_END_OF_STRING;
974	Log(("dbgDiggerLinuxLoadKernelSymbols: offName=%#x cLeft=%#x cbKernelNames=%#x\n",
975	offName, cLeft, pThis->cbKernelNames));
976	}
977	}
978
979	/*
980	* Link the module into the address space.
981	*/
982	if (RT_SUCCESS(rc))
983	{
984	RTDBGAS hAs = DBGFR3AsResolveAndRetain(pUVM, DBGF_AS_KERNEL);
985	if (hAs != NIL_RTDBGAS)
986	rc = RTDbgAsModuleLink(hAs, hMod, uKernelStart, RTDBGASLINK_FLAGS_REPLACE);
987	else
988	rc = VERR_INTERNAL_ERROR;
989	RTDbgAsRelease(hAs);
990	}
991	else
992	Log(("dbgDiggerLinuxLoadKernelSymbols: Failed: %Rrc\n", rc));
993	RTDbgModRelease(hMod);
994	}
995	else
996	Log(("dbgDiggerLinuxLoadKernelSymbols: RTDbgModCreate failed: %Rrc\n", rc));
997	}
998	else
999	Log(("dbgDiggerLinuxLoadKernelSymbols: Reading token index at %RGv failed: %Rrc\n",
1000	pThis->AddrKernelTokenIndex.FlatPtr, rc));
1001	RTMemFree(paoffTokens);
1002	}
1003	else
1004	Log(("dbgDiggerLinuxLoadKernelSymbols: Reading token table at %RGv failed: %Rrc\n",
1005	pThis->AddrKernelTokenTable.FlatPtr, rc));
1006	RTMemFree(pszzTokens);
1007	}
1008	else
1009	Log(("dbgDiggerLinuxLoadKernelSymbols: Reading encoded names at %RGv failed: %Rrc\n",
1010	pThis->AddrKernelNames.FlatPtr, rc));
1011	RTMemFree(pbNames);
1012	}
1013	else
1014	Log(("dbgDiggerLinuxLoadKernelSymbols: Reading symbol addresses at %RGv failed: %Rrc\n",
1015	pThis->AddrKernelAddresses.FlatPtr, rc));
1016	RTMemFree(pvAddresses);
1017	return rc;
1018	}
1019
1020
1021	/**
1022	* Checks if there is a likely kallsyms_names fragment at pHitAddr.
1023	*
1024	* @returns true if it's a likely fragment, false if not.
1025	* @param pUVM The user mode VM handle.
1026	* @param pHitAddr The address where paNeedle was found.
1027	* @param pabNeedle The fragment we've been searching for.
1028	* @param cbNeedle The length of the fragment.
1029	*/
1030	static bool dbgDiggerLinuxIsLikelyNameFragment(PUVM pUVM, PCDBGFADDRESS pHitAddr, uint8_t const *pabNeedle, uint8_t cbNeedle)
1031	{
1032	/*
1033	* Examples of lead and tail bytes of our choosen needle in a randomly
1034	* picked kernel:
1035	* k o b j
1036	* 22 6b 6f 62 6a aa
1037	* fc 6b 6f 62 6a aa
1038	* 82 6b 6f 62 6a 5f - ascii trail byte (_).
1039	* ee 6b 6f 62 6a aa
1040	* fc 6b 6f 62 6a 5f - ascii trail byte (_).
1041	* 0a 74 6b 6f 62 6a 5f ea - ascii lead (t) and trail (_) bytes.
1042	* 0b 54 6b 6f 62 6a aa - ascii lead byte (T).
1043	* ... omitting 29 samples similar to the last two ...
1044	* d8 6b 6f 62 6a aa
1045	* d8 6b 6f 62 6a aa
1046	* d8 6b 6f 62 6a aa
1047	* d8 6b 6f 62 6a aa
1048	* f9 5f 6b 6f 62 6a 5f 94 - ascii lead and trail bytes (_)
1049	* f9 5f 6b 6f 62 6a 0c - ascii lead byte (_).
1050	* fd 6b 6f 62 6a 0f
1051	* ... enough.
1052	*/
1053	uint8_t abBuf[32];
1054	DBGFADDRESS ReadAddr = *pHitAddr;
1055	DBGFR3AddrSub(&ReadAddr, 2);
1056	int rc = DBGFR3MemRead(pUVM, 0 /idCpu/, &ReadAddr, abBuf, 2 + cbNeedle + 2);
1057	if (RT_SUCCESS(rc))
1058	{
1059	if (memcmp(&abBuf[2], pabNeedle, cbNeedle) == 0) /* paranoia */
1060	{
1061	uint8_t const bLead = abBuf[1] == '_' \|\| abBuf[1] == 'T' \|\| abBuf[1] == 't' ? abBuf[0] : abBuf[1];
1062	uint8_t const offTail = 2 + cbNeedle;
1063	uint8_t const bTail = abBuf[offTail] == '_' ? abBuf[offTail] : abBuf[offTail + 1];
1064	if ( bLead >= 1 && (bLead < 0x20 \|\| bLead >= 0x80)
1065	&& bTail >= 1 && (bTail < 0x20 \|\| bTail >= 0x80))
1066	return true;
1067	Log(("dbgDiggerLinuxIsLikelyNameFragment: failed at %RGv: bLead=%#x bTail=%#x (offTail=%#x)\n",
1068	pHitAddr->FlatPtr, bLead, bTail, offTail));
1069	}
1070	else
1071	Log(("dbgDiggerLinuxIsLikelyNameFragment: failed at %RGv: Needle changed!\n", pHitAddr->FlatPtr));
1072	}
1073	else
1074	Log(("dbgDiggerLinuxIsLikelyNameFragment: failed at %RGv: %Rrc\n", pHitAddr->FlatPtr, rc));
1075
1076	return false;
1077	}
1078
1079
1080	/**
1081	* @copydoc DBGFOSREG::pfnInit
1082	*/
1083	static DECLCALLBACK(int) dbgDiggerLinuxInit(PUVM pUVM, void *pvData)
1084	{
1085	PDBGDIGGERLINUX pThis = (PDBGDIGGERLINUX)pvData;
1086	Assert(!pThis->fValid);
1087
1088	/*
1089	* Assume 64-bit kernels all live way beyond 32-bit address space.
1090	*/
1091	pThis->f64Bit = pThis->AddrLinuxBanner.FlatPtr > UINT32_MAX;
1092
1093	/*
1094	* Go looking for the kallsyms table. If it's there, it will be somewhere
1095	* after the linux_banner symbol, so use it for starting the search.
1096	*/
1097	DBGFADDRESS CurAddr = pThis->AddrLinuxBanner;
1098	uint32_t cbLeft = LNX_MAX_KERNEL_SIZE;
1099	while (cbLeft > 4096)
1100	{
1101	static const uint8_t s_abNeedle[] = "kobj";
1102	DBGFADDRESS HitAddr;
1103	int rc = DBGFR3MemScan(pUVM, 0 /idCpu/, &CurAddr, cbLeft, 1 /uAlign/,
1104	s_abNeedle, sizeof(s_abNeedle) - 1, &HitAddr);
1105	if (RT_FAILURE(rc))
1106	break;
1107	if (dbgDiggerLinuxIsLikelyNameFragment(pUVM, &HitAddr, s_abNeedle, sizeof(s_abNeedle) - 1))
1108	{
1109	/* There will be another hit near by. */
1110	DBGFR3AddrAdd(&HitAddr, 1);
1111	rc = DBGFR3MemScan(pUVM, 0 /idCpu/, &HitAddr, LNX_MAX_KALLSYMS_NAMES_SIZE, 1 /uAlign/,
1112	s_abNeedle, sizeof(s_abNeedle) - 1, &HitAddr);
1113	if ( RT_SUCCESS(rc)
1114	&& dbgDiggerLinuxIsLikelyNameFragment(pUVM, &HitAddr, s_abNeedle, sizeof(s_abNeedle) - 1))
1115	{
1116	/*
1117	* We've got a very likely candidate for a location inside kallsyms_names.
1118	* Try find the start of it, that is to say, try find kallsyms_num_syms.
1119	* kallsyms_num_syms is aligned on sizeof(unsigned long) boundrary
1120	*/
1121	rc = dbgDiggerLinuxFindStartOfNamesAndSymbolCount(pUVM, pThis, &HitAddr);
1122	if (RT_SUCCESS(rc))
1123	rc = dbgDiggerLinuxFindEndOfNamesAndMore(pUVM, pThis, &HitAddr);
1124	if (RT_SUCCESS(rc))
1125	rc = dbgDiggerLinuxFindTokenIndex(pUVM, pThis);
1126	if (RT_SUCCESS(rc))
1127	rc = dbgDiggerLinuxLoadKernelSymbols(pUVM, pThis);
1128	if (RT_SUCCESS(rc))
1129	break;
1130	}
1131	}
1132
1133	/*
1134	* Advance.
1135	*/
1136	RTGCUINTPTR cbDistance = HitAddr.FlatPtr - CurAddr.FlatPtr + sizeof(s_abNeedle) - 1;
1137	if (RT_UNLIKELY(cbDistance >= cbLeft))
1138	{
1139	Log(("dbgDiggerLinuxInit: Failed to find kallsyms\n"));
1140	break;
1141	}
1142	cbLeft -= cbDistance;
1143	DBGFR3AddrAdd(&CurAddr, cbDistance);
1144
1145	}
1146
1147	pThis->fValid = true;
1148	return VINF_SUCCESS;
1149	}
1150
1151
1152	/**
1153	* @copydoc DBGFOSREG::pfnProbe
1154	*/
1155	static DECLCALLBACK(bool) dbgDiggerLinuxProbe(PUVM pUVM, void *pvData)
1156	{
1157	PDBGDIGGERLINUX pThis = (PDBGDIGGERLINUX)pvData;
1158
1159	/*
1160	* Look for "Linux version " at the start of the rodata segment.
1161	* Hope that this comes before any message buffer or other similar string.
1162	*/
1163	for (unsigned i = 0; i < RT_ELEMENTS(g_au64LnxKernelAddresses); i++)
1164	{
1165	DBGFADDRESS KernelAddr;
1166	DBGFR3AddrFromFlat(pUVM, &KernelAddr, g_au64LnxKernelAddresses[i]);
1167	DBGFADDRESS HitAddr;
1168	static const uint8_t s_abLinuxVersion[] = "Linux version ";
1169	int rc = DBGFR3MemScan(pUVM, 0, &KernelAddr, LNX_MAX_KERNEL_SIZE, 1,
1170	s_abLinuxVersion, sizeof(s_abLinuxVersion) - 1, &HitAddr);
1171	if (RT_SUCCESS(rc))
1172	{
1173	char szTmp[128];
1174	char const *pszX = &szTmp[sizeof(s_abLinuxVersion) - 1];
1175	rc = DBGFR3MemReadString(pUVM, 0, &HitAddr, szTmp, sizeof(szTmp));
1176	if ( RT_SUCCESS(rc)
1177	&& ( ( pszX[0] == '2' /* 2.x.y with x in {0..6} */
1178	&& pszX[1] == '.'
1179	&& pszX[2] >= '0'
1180	&& pszX[2] <= '6')
1181	\|\| ( pszX[0] >= '3' /* 3.x, 4.x, ... 9.x */
1182	&& pszX[0] <= '9'
1183	&& pszX[1] == '.'
1184	&& pszX[2] >= '0'
1185	&& pszX[2] <= '9')
1186	)
1187	)
1188	{
1189	pThis->AddrKernelBase = KernelAddr;
1190	pThis->AddrLinuxBanner = HitAddr;
1191	return true;
1192	}
1193	}
1194	}
1195	return false;
1196	}
1197
1198
1199	/**
1200	* @copydoc DBGFOSREG::pfnDestruct
1201	*/
1202	static DECLCALLBACK(void) dbgDiggerLinuxDestruct(PUVM pUVM, void *pvData)
1203	{
1204
1205	}
1206
1207
1208	/**
1209	* @copydoc DBGFOSREG::pfnConstruct
1210	*/
1211	static DECLCALLBACK(int) dbgDiggerLinuxConstruct(PUVM pUVM, void *pvData)
1212	{
1213	PDBGDIGGERLINUX pThis = (PDBGDIGGERLINUX)pvData;
1214	pThis->IDmesg.u32Magic = DBGFOSIDMESG_MAGIC;
1215	pThis->IDmesg.pfnQueryKernelLog = dbgDiggerLinuxIDmsg_QueryKernelLog;
1216	pThis->IDmesg.u32EndMagic = DBGFOSIDMESG_MAGIC;
1217
1218	return VINF_SUCCESS;
1219	}
1220
1221
1222	const DBGFOSREG g_DBGDiggerLinux =
1223	{
1224	/* .u32Magic = */ DBGFOSREG_MAGIC,
1225	/* .fFlags = */ 0,
1226	/* .cbData = */ sizeof(DBGDIGGERLINUX),
1227	/* .szName = */ "Linux",
1228	/* .pfnConstruct = */ dbgDiggerLinuxConstruct,
1229	/* .pfnDestruct = */ dbgDiggerLinuxDestruct,
1230	/* .pfnProbe = */ dbgDiggerLinuxProbe,
1231	/* .pfnInit = */ dbgDiggerLinuxInit,
1232	/* .pfnRefresh = */ dbgDiggerLinuxRefresh,
1233	/* .pfnTerm = */ dbgDiggerLinuxTerm,
1234	/* .pfnQueryVersion = */ dbgDiggerLinuxQueryVersion,
1235	/* .pfnQueryInterface = */ dbgDiggerLinuxQueryInterface,
1236	/* .u32EndMagic = */ DBGFOSREG_MAGIC
1237	};
1238

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source: vbox/trunk/src/VBox/Debugger/DBGPlugInLinux.cpp@ 61039

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