DBGPlugInFreeBsd.cpp@ 75056

Last change on this file since 75056 was 73460, checked in by vboxsync, 6 years ago
IPRT,DBGF,Diggers: Moved DBGFRETURNTYPE and the unwind state structure to IPRT (dbg.h) in prep for debug module interface and more. Added stack unwind assist callback for the OS diggers so they can identify special stack frames and supply more info via the sure-register-value array and frame flags. Identify and decode NT/AMD64 trap frames.
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1	/* $Id: DBGPlugInFreeBsd.cpp 73460 2018-08-02 21:06:59Z vboxsync $ */
2	/** @file
3	* DBGPlugInFreeBsd - Debugger and Guest OS Digger Plugin For FreeBSD.
4	*/
5
6	/*
7	* Copyright (C) 2016-2017 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/asm.h>
27	#include <iprt/ctype.h>
28	#include <iprt/mem.h>
29	#include <iprt/stream.h>
30	#include <iprt/string.h>
31
32
33	/*********************************************************************************************************************************
34	* Defined Constants And Macros *
35	*********************************************************************************************************************************/
36	/** FreeBSD on little endian ASCII systems. */
37	#define DIG_FBSD_MOD_TAG UINT64_C(0x0044534265657246)
38
39
40	/*********************************************************************************************************************************
41	* Structures and Typedefs *
42	*********************************************************************************************************************************/
43
44	/**
45	* ELF headers union.
46	*/
47	typedef union ELFEHDRS
48	{
49	/** 32bit version of the ELF header. */
50	Elf32_Ehdr Hdr32;
51	/** 64bit version of the ELF header. */
52	Elf64_Ehdr Hdr64;
53	} ELFEHDRS;
54	/** Pointer to a ELF header union. */
55	typedef ELFEHDRS *PELFEHDRS;
56	/** Pointer to const ELF header union. */
57	typedef ELFEHDRS const *PCELFEHDRS;
58
59	/**
60	* ELF symbol entry union.
61	*/
62	typedef union ELFSYMS
63	{
64	/** 32bit version of the ELF section header. */
65	Elf32_Sym Hdr32;
66	/** 64bit version of the ELF section header. */
67	Elf64_Sym Hdr64;
68	} ELFSYMS;
69	/** Pointer to a ELF symbol entry union. */
70	typedef ELFSYMS *PELFSYMS;
71	/** Pointer to const ELF symbol entry union. */
72	typedef ELFSYMS const *PCELFSYMS;
73
74	/**
75	* Message buffer structure.
76	*/
77	typedef union FBSDMSGBUF
78	{
79	/** 32bit version. */
80	struct
81	{
82	/** Message buffer pointer. */
83	uint32_t msg_ptr;
84	/** Magic value to identify the structure. */
85	uint32_t msg_magic;
86	/** Size of the buffer area. */
87	uint32_t msg_size;
88	/** Write sequence number. */
89	uint32_t msg_wseq;
90	/** Read sequence number. */
91	uint32_t msg_rseq;
92	/** @todo More fields which are not required atm. */
93	} Hdr32;
94	/** 64bit version. */
95	struct
96	{
97	/** Message buffer pointer. */
98	uint64_t msg_ptr;
99	/** Magic value to identify the structure. */
100	uint32_t msg_magic;
101	/** Size of the buffer area. */
102	uint32_t msg_size;
103	/** Write sequence number. */
104	uint32_t msg_wseq;
105	/** Read sequence number. */
106	uint32_t msg_rseq;
107	/** @todo More fields which are not required atm. */
108	} Hdr64;
109	} FBSDMSGBUF;
110	/** Pointer to a message buffer structure. */
111	typedef FBSDMSGBUF *PFBSDMSGBUF;
112	/** Pointer to a const message buffer structure. */
113	typedef FBSDMSGBUF const *PCFBSDMSGBUF;
114
115	/** Magic value to identify the message buffer structure. */
116	#define FBSD_MSGBUF_MAGIC UINT32_C(0x063062)
117
118	/**
119	* FreeBSD guest OS digger instance data.
120	*/
121	typedef struct DBGDIGGERFBSD
122	{
123	/** Whether the information is valid or not.
124	* (For fending off illegal interface method calls.) */
125	bool fValid;
126	/** 64-bit/32-bit indicator. */
127	bool f64Bit;
128
129	/** Address of the start of the kernel ELF image,
130	* set during probing. */
131	DBGFADDRESS AddrKernelElfStart;
132	/** Address of the interpreter content aka "/red/herring". */
133	DBGFADDRESS AddrKernelInterp;
134	/** Address of the start of the text section. */
135	DBGFADDRESS AddrKernelText;
136
137	/** The kernel message log interface. */
138	DBGFOSIDMESG IDmesg;
139
140	} DBGDIGGERFBSD;
141	/** Pointer to the FreeBSD guest OS digger instance data. */
142	typedef DBGDIGGERFBSD *PDBGDIGGERFBSD;
143
144
145	/*********************************************************************************************************************************
146	* Defined Constants And Macros *
147	*********************************************************************************************************************************/
148	/** Min kernel address (32bit). */
149	#define FBSD32_MIN_KRNL_ADDR UINT32_C(0x80000000)
150	/** Max kernel address (32bit). */
151	#define FBSD32_MAX_KRNL_ADDR UINT32_C(0xfffff000)
152
153	/** Min kernel address (64bit). */
154	#define FBSD64_MIN_KRNL_ADDR UINT64_C(0xFFFFF80000000000)
155	/** Max kernel address (64bit). */
156	#define FBSD64_MAX_KRNL_ADDR UINT64_C(0xFFFFFFFFFFF00000)
157
158
159	/** Validates a 32-bit FreeBSD kernel address */
160	#define FBSD32_VALID_ADDRESS(Addr) ( (Addr) > FBSD32_MIN_KRNL_ADDR \
161	&& (Addr) < FBSD32_MAX_KRNL_ADDR)
162	/** Validates a 64-bit FreeBSD kernel address */
163	#define FBSD64_VALID_ADDRESS(Addr) ( (Addr) > FBSD64_MIN_KRNL_ADDR \
164	&& (Addr) < FBSD64_MAX_KRNL_ADDR)
165
166	/** Validates a FreeBSD kernel address. */
167	#define FBSD_VALID_ADDRESS(a_pThis, a_Addr) ((a_pThis)->f64Bit ? FBSD64_VALID_ADDRESS(a_Addr) : FBSD32_VALID_ADDRESS(a_Addr))
168
169	/** Maximum offset from the start of the ELF image we look for the /red/herring .interp section content. */
170	#define FBSD_MAX_INTERP_OFFSET _16K
171	/** The max kernel size. */
172	#define FBSD_MAX_KERNEL_SIZE UINT32_C(0x0f000000)
173
174	/** Versioned and bitness wrapper. */
175	#define FBSD_UNION(a_pThis, a_pUnion, a_Member) ((a_pThis)->f64Bit ? (a_pUnion)->Hdr64. a_Member : (a_pUnion)->Hdr32. a_Member )
176
177
178	/*********************************************************************************************************************************
179	* Internal Functions *
180	*********************************************************************************************************************************/
181	static DECLCALLBACK(int) dbgDiggerFreeBsdInit(PUVM pUVM, void *pvData);
182
183
184	/*********************************************************************************************************************************
185	* Global Variables *
186	*********************************************************************************************************************************/
187	/** Table of common FreeBSD kernel addresses. */
188	static uint64_t g_au64FreeBsdKernelAddresses[] =
189	{
190	UINT64_C(0xc0100000),
191	UINT64_C(0xffffffff80100000)
192	};
193	/** Magic string which resides in the .interp section of the image. */
194	static const uint8_t g_abNeedleInterp[] = "/red/herring";
195
196
197	/**
198	* Load the symbols from the .dynsym and .dynstr sections given
199	* by their address in guest memory.
200	*
201	* @returns VBox status code.
202	* @param pThis The instance data.
203	* @param pUVM The user mode VM handle.
204	* @param pszName The image name.
205	* @param uKernelStart The kernel start address.
206	* @param cbKernel Size of the kernel image.
207	* @param pAddrDynsym Start address of the .dynsym section.
208	* @param cSymbols Number of symbols in the .dynsym section.
209	* @param pAddrDynstr Start address of the .dynstr section containing the symbol names.
210	* @param cbDynstr Size of the .dynstr section.
211	*/
212	static int dbgDiggerFreeBsdLoadSymbols(PDBGDIGGERFBSD pThis, PUVM pUVM, const char *pszName, RTGCUINTPTR uKernelStart,
213	size_t cbKernel, PDBGFADDRESS pAddrDynsym, uint32_t cSymbols, PDBGFADDRESS pAddrDynstr,
214	size_t cbDynstr)
215	{
216	LogFlowFunc(("pThis=%#p pszName=%s uKernelStart=%RGv cbKernel=%zu pAddrDynsym=%#p{%RGv} cSymbols=%u pAddrDynstr=%#p{%RGv} cbDynstr=%zu\n",
217	pThis, pszName, uKernelStart, cbKernel, pAddrDynsym, pAddrDynsym->FlatPtr, cSymbols, pAddrDynstr, pAddrDynstr->FlatPtr, cbDynstr));
218
219	char pbDynstr = (char )RTMemAllocZ(cbDynstr);
220	int rc = DBGFR3MemRead(pUVM, 0 /idCpu/, pAddrDynstr, pbDynstr, cbDynstr);
221	if (RT_SUCCESS(rc))
222	{
223	uint32_t cbDynsymEnt = pThis->f64Bit ? sizeof(Elf64_Sym) : sizeof(Elf32_Sym);
224	uint8_t pbDynsym = (uint8_t )RTMemAllocZ(cSymbols * cbDynsymEnt);
225	rc = DBGFR3MemRead(pUVM, 0 /idCpu/, pAddrDynsym, pbDynsym, cSymbols * cbDynsymEnt);
226	if (RT_SUCCESS(rc))
227	{
228	/*
229	* Create a module for the kernel.
230	*/
231	RTDBGMOD hMod;
232	rc = RTDbgModCreate(&hMod, pszName, cbKernel, 0 /fFlags/);
233	if (RT_SUCCESS(rc))
234	{
235	rc = RTDbgModSetTag(hMod, DIG_FBSD_MOD_TAG); AssertRC(rc);
236	rc = VINF_SUCCESS;
237
238	/*
239	* Enumerate the symbols.
240	*/
241	uint32_t cLeft = cSymbols;
242	while (cLeft-- > 0 && RT_SUCCESS(rc))
243	{
244	PCELFSYMS pSym = (PCELFSYMS)&pbDynsym[cLeft * cbDynsymEnt];
245	uint32_t idxSymStr = FBSD_UNION(pThis, pSym, st_name);
246	uint8_t uType = FBSD_UNION(pThis, pSym, st_info);
247	RTGCUINTPTR AddrVal = FBSD_UNION(pThis, pSym, st_value);
248	size_t cbSymVal = FBSD_UNION(pThis, pSym, st_size);
249
250	/* Add it without the type char. */
251	RT_NOREF(uType);
252	if (AddrVal <= uKernelStart + cbKernel)
253	{
254	rc = RTDbgModSymbolAdd(hMod, &pbDynstr[idxSymStr], RTDBGSEGIDX_RVA, AddrVal - uKernelStart,
255	cbSymVal, 0 /fFlags/, NULL);
256	if (RT_FAILURE(rc))
257	{
258	if ( rc == VERR_DBG_SYMBOL_NAME_OUT_OF_RANGE
259	\|\| rc == VERR_DBG_INVALID_RVA
260	\|\| rc == VERR_DBG_ADDRESS_CONFLICT
261	\|\| rc == VERR_DBG_DUPLICATE_SYMBOL)
262	{
263	Log2(("dbgDiggerFreeBsdLoadSymbols: RTDbgModSymbolAdd(,%s,) failed %Rrc (ignored)\n",
264	&pbDynstr[idxSymStr], rc));
265	rc = VINF_SUCCESS;
266	}
267	else
268	Log(("dbgDiggerFreeBsdLoadSymbols: RTDbgModSymbolAdd(,%s,) failed %Rrc\n",
269	&pbDynstr[idxSymStr], rc));
270	}
271	}
272	}
273
274	/*
275	* Link the module into the address space.
276	*/
277	if (RT_SUCCESS(rc))
278	{
279	RTDBGAS hAs = DBGFR3AsResolveAndRetain(pUVM, DBGF_AS_KERNEL);
280	if (hAs != NIL_RTDBGAS)
281	rc = RTDbgAsModuleLink(hAs, hMod, uKernelStart, RTDBGASLINK_FLAGS_REPLACE);
282	else
283	rc = VERR_INTERNAL_ERROR;
284	RTDbgAsRelease(hAs);
285	}
286	else
287	Log(("dbgDiggerFreeBsdLoadSymbols: Failed: %Rrc\n", rc));
288	RTDbgModRelease(hMod);
289	}
290	else
291	Log(("dbgDiggerFreeBsdLoadSymbols: RTDbgModCreate failed: %Rrc\n", rc));
292	}
293	else
294	Log(("dbgDiggerFreeBsdLoadSymbols: Reading symbol table at %RGv failed: %Rrc\n",
295	pAddrDynsym->FlatPtr, rc));
296	RTMemFree(pbDynsym);
297	}
298	else
299	Log(("dbgDiggerFreeBsdLoadSymbols: Reading symbol string table at %RGv failed: %Rrc\n",
300	pAddrDynstr->FlatPtr, rc));
301	RTMemFree(pbDynstr);
302
303	LogFlowFunc(("returns %Rrc\n", rc));
304	return rc;
305	}
306
307	/**
308	* Process the kernel image.
309	*
310	* @param pThis The instance data.
311	* @param pUVM The user mode VM handle.
312	* @param pszName The image name.
313	*/
314	static void dbgDiggerFreeBsdProcessKernelImage(PDBGDIGGERFBSD pThis, PUVM pUVM, const char *pszName)
315	{
316	/*
317	* FreeBSD has parts of the kernel ELF image in guest memory, starting with the
318	* ELF header and the content of the sections which are indicated to be loaded
319	* into memory (text, rodata, etc.) of course. Whats missing are the section headers
320	* which is understandable but unfortunate because it would make our life easier.
321	*
322	* All checked FreeBSD kernels so far have the following layout in the kernel:
323	* [.interp] - contiains the /red/herring string we used for probing earlier
324	* [.hash] - contains the hashes of the symbol names, 8 byte alignment on 64bit, 4 byte on 32bit
325	* [.dynsym] - contains the ELF symbol descriptors, 8 byte alignment, 4 byte on 32bit
326	* [.dynstr] - contains the symbol names as a string table, 1 byte alignmnt
327	* [.text] - contains the executable code, 16 byte alignment.
328	* The sections are always adjacent (sans alignment) so we just parse the .hash section right after
329	* .interp, ELF states that it can contain 32bit or 64bit words but all observed kernels
330	* always use 32bit words. It contains two counters at the beginning which we can use to
331	* deduct the .hash section size and the beginning of .dynsym.
332	* .dynsym contains an array of symbol descriptors which have a fixed size depending on the
333	* guest bitness.
334	* Finding the end of .dynsym is not easily doable as there is no counter available (it lives
335	* in the section headers) at this point so we just have to check whether the record is valid
336	* and if not check if it contains an ASCII string which marks the start of the .dynstr section.
337	*/
338
339	/* Calculate the start of the .hash section. */
340	DBGFADDRESS AddrHashStart = pThis->AddrKernelInterp;
341	DBGFR3AddrAdd(&AddrHashStart, sizeof(g_abNeedleInterp));
342	AddrHashStart.FlatPtr = RT_ALIGN_GCPT(AddrHashStart.FlatPtr, pThis->f64Bit ? 8 : 4, RTGCUINTPTR);
343	uint32_t au32Counters[2];
344	int rc = DBGFR3MemRead(pUVM, 0 /idCpu/, &AddrHashStart, &au32Counters[0], sizeof(au32Counters));
345	if (RT_SUCCESS(rc))
346	{
347	size_t cbHash = (au32Counters[0] + au32Counters[1] + 2) * sizeof(uint32_t);
348	if (AddrHashStart.FlatPtr + cbHash < pThis->AddrKernelText.FlatPtr) /* Should be much smaller */
349	{
350	DBGFADDRESS AddrDynsymStart = AddrHashStart;
351	uint32_t cSymbols = 0;
352	size_t cbKernel = 0;
353	RTGCUINTPTR uKernelStart = pThis->AddrKernelElfStart.FlatPtr;
354
355	DBGFR3AddrAdd(&AddrDynsymStart, cbHash);
356	AddrDynsymStart.FlatPtr = RT_ALIGN_GCPT(AddrDynsymStart.FlatPtr, pThis->f64Bit ? 8 : 4, RTGCUINTPTR);
357
358	DBGFADDRESS AddrDynstrStart = AddrDynsymStart;
359	while (AddrDynstrStart.FlatPtr < pThis->AddrKernelText.FlatPtr)
360	{
361	size_t cbDynSymEnt = pThis->f64Bit ? sizeof(Elf64_Sym) : sizeof(Elf32_Sym);
362	uint8_t abBuf[_16K];
363	size_t cbToRead = RT_MIN(sizeof(abBuf), pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr);
364
365	rc = DBGFR3MemRead(pUVM, 0 /idCpu/, &AddrDynstrStart, &abBuf[0], cbToRead);
366	if (RT_FAILURE(rc))
367	break;
368
369	for (unsigned i = 0; i < cbToRead / cbDynSymEnt; i++)
370	{
371	PCELFSYMS pSym = (PCELFSYMS)&abBuf[i * cbDynSymEnt];
372	uint32_t idxSymStr = FBSD_UNION(pThis, pSym, st_name);
373	uint8_t uType = FBSD_UNION(pThis, pSym, st_info);
374	RTGCUINTPTR AddrVal = FBSD_UNION(pThis, pSym, st_value);
375	size_t cbSymVal = FBSD_UNION(pThis, pSym, st_size);
376
377	/*
378	* If the entry doesn't look valid check whether it contains an ASCII string,
379	* we then found the start of the .dynstr section.
380	*/
381	RT_NOREF(uType);
382	if ( ELF32_ST_TYPE(uType) != STT_NOTYPE
383	&& ( !FBSD_VALID_ADDRESS(pThis, AddrVal)
384	\|\| cbSymVal > FBSD_MAX_KERNEL_SIZE
385	\|\| idxSymStr > pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr))
386	{
387	LogFlowFunc(("Invalid symbol table entry found at %RGv\n",
388	AddrDynstrStart.FlatPtr + i * cbDynSymEnt));
389
390	uint8_t pbBuf = &abBuf[i cbDynSymEnt];
391	size_t cbLeft = cbToRead - i * cbDynSymEnt;
392	/*
393	* Check to the end of the buffer whether it contains only a certain set of
394	* ASCII characters and 0 terminators.
395	*/
396	while ( cbLeft > 0
397	&& ( RT_C_IS_ALNUM(*pbBuf)
398	\|\| *pbBuf == '_'
399	\|\| *pbBuf == '\0'
400	\|\| *pbBuf == '.'))
401	{
402	cbLeft--;
403	pbBuf++;
404	}
405
406	if (!cbLeft)
407	{
408	DBGFR3AddrAdd(&AddrDynstrStart, i * cbDynSymEnt);
409	LogFlowFunc(("Found all required section start addresses (.dynsym=%RGv cSymbols=%u, .dynstr=%RGv cb=%u)\n",
410	AddrDynsymStart.FlatPtr, cSymbols, AddrDynstrStart.FlatPtr,
411	pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr));
412	dbgDiggerFreeBsdLoadSymbols(pThis, pUVM, pszName, uKernelStart, cbKernel, &AddrDynsymStart, cSymbols, &AddrDynstrStart,
413	pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr);
414	return;
415	}
416	else
417	LogFlowFunc(("Found invalid ASCII character in .dynstr section candidate: %#x\n", *pbBuf));
418	}
419	else
420	{
421	cSymbols++;
422	if ( ELF32_ST_TYPE(uType) != STT_NOTYPE
423	&& FBSD_VALID_ADDRESS(pThis, AddrVal))
424	{
425	uKernelStart = RT_MIN(uKernelStart, AddrVal);
426	cbKernel = RT_MAX(cbKernel, AddrVal + cbSymVal - uKernelStart);
427	}
428	}
429	}
430
431	/* Don't account incomplete entries. */
432	DBGFR3AddrAdd(&AddrDynstrStart, (cbToRead / cbDynSymEnt) * cbDynSymEnt);
433	}
434	}
435	else
436	LogFlowFunc((".hash section overlaps with .text section: %zu (expected much less than %u)\n", cbHash,
437	pThis->AddrKernelText.FlatPtr - AddrHashStart.FlatPtr));
438	}
439	}
440
441
442	/**
443	* @interface_method_impl{DBGFOSIDMESG,pfnQueryKernelLog}
444	*/
445	static DECLCALLBACK(int) dbgDiggerFreeBsdIDmsg_QueryKernelLog(PDBGFOSIDMESG pThis, PUVM pUVM, uint32_t fFlags, uint32_t cMessages,
446	char pszBuf, size_t cbBuf, size_t pcbActual)
447	{
448	RT_NOREF1(fFlags);
449	PDBGDIGGERFBSD pData = RT_FROM_MEMBER(pThis, DBGDIGGERFBSD, IDmesg);
450
451	if (cMessages < 1)
452	return VERR_INVALID_PARAMETER;
453
454	/* Resolve the message buffer address from the msgbufp symbol. */
455	RTDBGSYMBOL SymInfo;
456	int rc = DBGFR3AsSymbolByName(pUVM, DBGF_AS_KERNEL, "kernel!msgbufp", &SymInfo, NULL);
457	if (RT_SUCCESS(rc))
458	{
459	DBGFADDRESS AddrMsgBuf;
460
461	/* Read the message buffer pointer. */
462	RTGCPTR GCPtrMsgBufP = 0;
463	rc = DBGFR3MemRead(pUVM, 0 /idCpu/, DBGFR3AddrFromFlat(pUVM, &AddrMsgBuf, SymInfo.Value),
464	&GCPtrMsgBufP, pData->f64Bit ? sizeof(uint64_t) : sizeof(uint32_t));
465	if (RT_FAILURE(rc))
466	{
467	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: failed to read msgbufp at %RGv: %Rrc\n", AddrMsgBuf.FlatPtr, rc));
468	return VERR_NOT_FOUND;
469	}
470	if (!FBSD_VALID_ADDRESS(pData, GCPtrMsgBufP))
471	{
472	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: Invalid address for msgbufp: %RGv\n", GCPtrMsgBufP));
473	return VERR_NOT_FOUND;
474	}
475
476	/* Read the structure. */
477	FBSDMSGBUF MsgBuf;
478	rc = DBGFR3MemRead(pUVM, 0 /idCpu/, DBGFR3AddrFromFlat(pUVM, &AddrMsgBuf, GCPtrMsgBufP),
479	&MsgBuf, sizeof(MsgBuf));
480	if (RT_SUCCESS(rc))
481	{
482	RTGCUINTPTR AddrBuf = FBSD_UNION(pData, &MsgBuf, msg_ptr);
483	uint32_t cbMsgBuf = FBSD_UNION(pData, &MsgBuf, msg_size);
484	uint32_t uMsgBufSeqR = FBSD_UNION(pData, &MsgBuf, msg_rseq);
485	uint32_t uMsgBufSeqW = FBSD_UNION(pData, &MsgBuf, msg_wseq);
486
487	/*
488	* Validate the structure.
489	*/
490	if ( FBSD_UNION(pData, &MsgBuf, msg_magic) != FBSD_MSGBUF_MAGIC
491	\|\| cbMsgBuf < UINT32_C(4096)
492	\|\| cbMsgBuf > 16*_1M
493	\|\| FBSD_UNION(pData, &MsgBuf, msg_rseq) > cbMsgBuf
494	\|\| FBSD_UNION(pData, &MsgBuf, msg_wseq) > cbMsgBuf
495	\|\| !FBSD_VALID_ADDRESS(pData, AddrBuf) )
496	{
497	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: Invalid MsgBuf data: msg_magic=%#x msg_size=%#x msg_rseq=%#x msg_wseq=%#x msg_ptr=%RGv\n",
498	FBSD_UNION(pData, &MsgBuf, msg_magic), cbMsgBuf, uMsgBufSeqR, uMsgBufSeqW, AddrBuf));
499	return VERR_INVALID_STATE;
500	}
501
502	/*
503	* Read the buffer.
504	*/
505	char pchMsgBuf = (char )RTMemAlloc(cbMsgBuf);
506	if (!pchMsgBuf)
507	{
508	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: Failed to allocate %#x bytes of memory for the log buffer\n",
509	cbMsgBuf));
510	return VERR_INVALID_STATE;
511	}
512	rc = DBGFR3MemRead(pUVM, 0 /idCpu/, DBGFR3AddrFromFlat(pUVM, &AddrMsgBuf, AddrBuf), pchMsgBuf, cbMsgBuf);
513	if (RT_SUCCESS(rc))
514	{
515	/*
516	* Copy it out raw.
517	*/
518	uint32_t offDst = 0;
519	if (uMsgBufSeqR < uMsgBufSeqW)
520	{
521	/* Single chunk between the read and write offsets. */
522	uint32_t cbToCopy = uMsgBufSeqW - uMsgBufSeqR;
523	if (cbToCopy < cbBuf)
524	{
525	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbToCopy);
526	pszBuf[cbToCopy] = '\0';
527	rc = VINF_SUCCESS;
528	}
529	else
530	{
531	if (cbBuf)
532	{
533	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbBuf - 1);
534	pszBuf[cbBuf - 1] = '\0';
535	}
536	rc = VERR_BUFFER_OVERFLOW;
537	}
538	offDst = cbToCopy + 1;
539	}
540	else
541	{
542	/* Two chunks, read offset to end, start to write offset. */
543	uint32_t cbFirst = cbMsgBuf - uMsgBufSeqR;
544	uint32_t cbSecond = uMsgBufSeqW;
545	if (cbFirst + cbSecond < cbBuf)
546	{
547	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbFirst);
548	memcpy(&pszBuf[cbFirst], pchMsgBuf, cbSecond);
549	offDst = cbFirst + cbSecond;
550	pszBuf[offDst++] = '\0';
551	rc = VINF_SUCCESS;
552	}
553	else
554	{
555	offDst = cbFirst + cbSecond + 1;
556	if (cbFirst < cbBuf)
557	{
558	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbFirst);
559	memcpy(&pszBuf[cbFirst], pchMsgBuf, cbBuf - cbFirst);
560	pszBuf[cbBuf - 1] = '\0';
561	}
562	else if (cbBuf)
563	{
564	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbBuf - 1);
565	pszBuf[cbBuf - 1] = '\0';
566	}
567	rc = VERR_BUFFER_OVERFLOW;
568	}
569	}
570
571	if (pcbActual)
572	*pcbActual = offDst;
573	}
574	else
575	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: Error reading %#x bytes at %RGv: %Rrc\n", cbBuf, AddrBuf, rc));
576	RTMemFree(pchMsgBuf);
577	}
578	else
579	LogFlowFunc(("Failed to read message buffer header: %Rrc\n", rc));
580	}
581
582	return rc;
583	}
584
585
586	/**
587	* @copydoc DBGFOSREG::pfnStackUnwindAssist
588	*/
589	static DECLCALLBACK(int) dbgDiggerFreeBsdStackUnwindAssist(PUVM pUVM, void *pvData, VMCPUID idCpu, PDBGFSTACKFRAME pFrame,
590	PRTDBGUNWINDSTATE pState, PCCPUMCTX pInitialCtx, RTDBGAS hAs,
591	uint64_t *puScratch)
592	{
593	RT_NOREF(pUVM, pvData, idCpu, pFrame, pState, pInitialCtx, hAs, puScratch);
594	return VINF_SUCCESS;
595	}
596
597
598	/**
599	* @copydoc DBGFOSREG::pfnQueryInterface
600	*/
601	static DECLCALLBACK(void ) dbgDiggerFreeBsdQueryInterface(PUVM pUVM, void pvData, DBGFOSINTERFACE enmIf)
602	{
603	RT_NOREF1(pUVM);
604	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
605	switch (enmIf)
606	{
607	case DBGFOSINTERFACE_DMESG:
608	return &pThis->IDmesg;
609
610	default:
611	return NULL;
612	}
613	}
614
615
616	/**
617	* @copydoc DBGFOSREG::pfnQueryVersion
618	*/
619	static DECLCALLBACK(int) dbgDiggerFreeBsdQueryVersion(PUVM pUVM, void pvData, char pszVersion, size_t cchVersion)
620	{
621	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
622	Assert(pThis->fValid); RT_NOREF(pThis);
623
624	RTDBGSYMBOL SymInfo;
625	int rc = DBGFR3AsSymbolByName(pUVM, DBGF_AS_KERNEL, "kernel!version", &SymInfo, NULL);
626	if (RT_SUCCESS(rc))
627	{
628	DBGFADDRESS AddrVersion;
629	DBGFR3AddrFromFlat(pUVM, &AddrVersion, SymInfo.Value);
630
631	rc = DBGFR3MemReadString(pUVM, 0, &AddrVersion, pszVersion, cchVersion);
632	if (RT_SUCCESS(rc))
633	{
634	char *pszEnd = RTStrEnd(pszVersion, cchVersion);
635	AssertReturn(pszEnd, VERR_BUFFER_OVERFLOW);
636	while ( pszEnd > pszVersion
637	&& RT_C_IS_SPACE(pszEnd[-1]))
638	pszEnd--;
639	*pszEnd = '\0';
640	}
641	else
642	RTStrPrintf(pszVersion, cchVersion, "DBGFR3MemReadString -> %Rrc", rc);
643	}
644
645	return rc;
646	}
647
648
649
650	/**
651	* @copydoc DBGFOSREG::pfnTerm
652	*/
653	static DECLCALLBACK(void) dbgDiggerFreeBsdTerm(PUVM pUVM, void *pvData)
654	{
655	RT_NOREF1(pUVM);
656	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
657	Assert(pThis->fValid);
658
659	RT_NOREF1(pUVM);
660
661	pThis->fValid = false;
662	}
663
664
665	/**
666	* @copydoc DBGFOSREG::pfnRefresh
667	*/
668	static DECLCALLBACK(int) dbgDiggerFreeBsdRefresh(PUVM pUVM, void *pvData)
669	{
670	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
671	NOREF(pThis);
672	Assert(pThis->fValid);
673
674	dbgDiggerFreeBsdTerm(pUVM, pvData);
675	return dbgDiggerFreeBsdInit(pUVM, pvData);
676	}
677
678
679	/**
680	* @copydoc DBGFOSREG::pfnInit
681	*/
682	static DECLCALLBACK(int) dbgDiggerFreeBsdInit(PUVM pUVM, void *pvData)
683	{
684	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
685	Assert(!pThis->fValid);
686
687	RT_NOREF1(pUVM);
688
689	dbgDiggerFreeBsdProcessKernelImage(pThis, pUVM, "kernel");
690	pThis->fValid = true;
691	return VINF_SUCCESS;
692	}
693
694
695	/**
696	* @copydoc DBGFOSREG::pfnProbe
697	*/
698	static DECLCALLBACK(bool) dbgDiggerFreeBsdProbe(PUVM pUVM, void *pvData)
699	{
700	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
701
702	/*
703	* Look for the magic ELF header near the known start addresses.
704	* If one is found look for the magic "/red/herring" string which is in the
705	* "interp" section not far away and then validate the start of the ELF header
706	* to be sure.
707	*/
708	for (unsigned i = 0; i < RT_ELEMENTS(g_au64FreeBsdKernelAddresses); i++)
709	{
710	static const uint8_t s_abNeedle[] = ELFMAG;
711	DBGFADDRESS KernelAddr;
712	DBGFR3AddrFromFlat(pUVM, &KernelAddr, g_au64FreeBsdKernelAddresses[i]);
713	DBGFADDRESS HitAddr;
714	uint32_t cbLeft = FBSD_MAX_KERNEL_SIZE;
715
716	while (cbLeft > X86_PAGE_4K_SIZE)
717	{
718	int rc = DBGFR3MemScan(pUVM, 0 /idCpu/, &KernelAddr, cbLeft, 1,
719	s_abNeedle, sizeof(s_abNeedle) - 1, &HitAddr);
720	if (RT_FAILURE(rc))
721	break;
722
723	/*
724	* Look for the magic "/red/herring" near the header and verify the basic
725	* ELF header.
726	*/
727	DBGFADDRESS HitAddrInterp;
728	rc = DBGFR3MemScan(pUVM, 0 /idCpu/, &HitAddr, FBSD_MAX_INTERP_OFFSET, 1,
729	g_abNeedleInterp, sizeof(g_abNeedleInterp), &HitAddrInterp);
730	if (RT_SUCCESS(rc))
731	{
732	union
733	{
734	uint8_t ab[2 * X86_PAGE_4K_SIZE];
735	Elf32_Ehdr Hdr32;
736	Elf64_Ehdr Hdr64;
737	} ElfHdr;
738	AssertCompileMembersSameSizeAndOffset(Elf64_Ehdr, e_ident, Elf32_Ehdr, e_ident);
739	AssertCompileMembersSameSizeAndOffset(Elf64_Ehdr, e_type, Elf32_Ehdr, e_type);
740	AssertCompileMembersSameSizeAndOffset(Elf64_Ehdr, e_machine, Elf32_Ehdr, e_machine);
741	AssertCompileMembersSameSizeAndOffset(Elf64_Ehdr, e_version, Elf32_Ehdr, e_version);
742
743	rc = DBGFR3MemRead(pUVM, 0 /idCpu/, &HitAddr, &ElfHdr.ab[0], X86_PAGE_4K_SIZE);
744	if (RT_SUCCESS(rc))
745	{
746	/* We verified the magic above already by scanning for it. */
747	if ( ( ElfHdr.Hdr32.e_ident[EI_CLASS] == ELFCLASS32
748	\|\| ElfHdr.Hdr32.e_ident[EI_CLASS] == ELFCLASS64)
749	&& ElfHdr.Hdr32.e_ident[EI_DATA] == ELFDATA2LSB
750	&& ElfHdr.Hdr32.e_ident[EI_VERSION] == EV_CURRENT
751	&& ElfHdr.Hdr32.e_ident[EI_OSABI] == ELFOSABI_FREEBSD
752	&& ElfHdr.Hdr32.e_type == ET_EXEC
753	&& ( ElfHdr.Hdr32.e_machine == EM_386
754	\|\| ElfHdr.Hdr32.e_machine == EM_X86_64)
755	&& ElfHdr.Hdr32.e_version == EV_CURRENT)
756	{
757	pThis->f64Bit = ElfHdr.Hdr32.e_ident[EI_CLASS] == ELFCLASS64;
758	pThis->AddrKernelElfStart = HitAddr;
759	pThis->AddrKernelInterp = HitAddrInterp;
760	pThis->AddrKernelText.FlatPtr = FBSD_UNION(pThis, &ElfHdr, e_entry);
761	LogFunc(("Found %s FreeBSD kernel at %RGv (.interp section at %RGv, .text section at %RGv)\n",
762	pThis->f64Bit ? "amd64" : "i386", pThis->AddrKernelElfStart.FlatPtr,
763	pThis->AddrKernelInterp.FlatPtr, pThis->AddrKernelText.FlatPtr));
764	return true;
765	}
766	}
767	}
768
769	/*
770	* Advance.
771	*/
772	RTGCUINTPTR cbDistance = HitAddr.FlatPtr - KernelAddr.FlatPtr + sizeof(s_abNeedle) - 1;
773	if (RT_UNLIKELY(cbDistance >= cbLeft))
774	break;
775
776	cbLeft -= cbDistance;
777	DBGFR3AddrAdd(&KernelAddr, cbDistance);
778	}
779	}
780	return false;
781	}
782
783
784	/**
785	* @copydoc DBGFOSREG::pfnDestruct
786	*/
787	static DECLCALLBACK(void) dbgDiggerFreeBsdDestruct(PUVM pUVM, void *pvData)
788	{
789	RT_NOREF2(pUVM, pvData);
790	}
791
792
793	/**
794	* @copydoc DBGFOSREG::pfnConstruct
795	*/
796	static DECLCALLBACK(int) dbgDiggerFreeBsdConstruct(PUVM pUVM, void *pvData)
797	{
798	RT_NOREF1(pUVM);
799	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
800
801	pThis->fValid = false;
802	pThis->f64Bit = false;
803	pThis->IDmesg.u32Magic = DBGFOSIDMESG_MAGIC;
804	pThis->IDmesg.pfnQueryKernelLog = dbgDiggerFreeBsdIDmsg_QueryKernelLog;
805	pThis->IDmesg.u32EndMagic = DBGFOSIDMESG_MAGIC;
806
807	return VINF_SUCCESS;
808	}
809
810
811	const DBGFOSREG g_DBGDiggerFreeBsd =
812	{
813	/* .u32Magic = */ DBGFOSREG_MAGIC,
814	/* .fFlags = */ 0,
815	/* .cbData = */ sizeof(DBGDIGGERFBSD),
816	/* .szName = */ "FreeBSD",
817	/* .pfnConstruct = */ dbgDiggerFreeBsdConstruct,
818	/* .pfnDestruct = */ dbgDiggerFreeBsdDestruct,
819	/* .pfnProbe = */ dbgDiggerFreeBsdProbe,
820	/* .pfnInit = */ dbgDiggerFreeBsdInit,
821	/* .pfnRefresh = */ dbgDiggerFreeBsdRefresh,
822	/* .pfnTerm = */ dbgDiggerFreeBsdTerm,
823	/* .pfnQueryVersion = */ dbgDiggerFreeBsdQueryVersion,
824	/* .pfnQueryInterface = */ dbgDiggerFreeBsdQueryInterface,
825	/* .pfnStackUnwindAssist = */ dbgDiggerFreeBsdStackUnwindAssist,
826	/* .u32EndMagic = */ DBGFOSREG_MAGIC
827	};
828

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source: vbox/trunk/src/VBox/Debugger/DBGPlugInFreeBsd.cpp@ 75056

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