DBGPlugInFreeBsd.cpp@ 78376

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1	/* $Id: DBGPlugInFreeBsd.cpp 77147 2019-02-03 23:38:41Z vboxsync $ */
2	/** @file
3	* DBGPlugInFreeBsd - Debugger and Guest OS Digger Plugin For FreeBSD.
4	*/
5
6	/*
7	* Copyright (C) 2016-2019 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/err.h>
29	#include <iprt/mem.h>
30	#include <iprt/stream.h>
31	#include <iprt/string.h>
32
33
34	/*********************************************************************************************************************************
35	* Defined Constants And Macros *
36	*********************************************************************************************************************************/
37	/** FreeBSD on little endian ASCII systems. */
38	#define DIG_FBSD_MOD_TAG UINT64_C(0x0044534265657246)
39
40
41	/*********************************************************************************************************************************
42	* Structures and Typedefs *
43	*********************************************************************************************************************************/
44
45	/**
46	* FreeBSD .dynstr and .dynsym location probing state.
47	*/
48	typedef enum FBSDPROBESTATE
49	{
50	/** Invalid state. */
51	FBSDPROBESTATE_INVALID = 0,
52	/** Searching for the end of the .dynstr section (terminator). */
53	FBSDPROBESTATE_DYNSTR_END,
54	/** Last symbol was a symbol terminator character. */
55	FBSDPROBESTATE_DYNSTR_SYM_TERMINATOR,
56	/** Last symbol was a symbol character. */
57	FBSDPROBESTATE_DYNSTR_SYM_CHAR
58	} FBSDPROBESTATE;
59
60	/**
61	* ELF headers union.
62	*/
63	typedef union ELFEHDRS
64	{
65	/** 32bit version of the ELF header. */
66	Elf32_Ehdr Hdr32;
67	/** 64bit version of the ELF header. */
68	Elf64_Ehdr Hdr64;
69	} ELFEHDRS;
70	/** Pointer to a ELF header union. */
71	typedef ELFEHDRS *PELFEHDRS;
72	/** Pointer to const ELF header union. */
73	typedef ELFEHDRS const *PCELFEHDRS;
74
75	/**
76	* ELF symbol entry union.
77	*/
78	typedef union ELFSYMS
79	{
80	/** 32bit version of the ELF section header. */
81	Elf32_Sym Hdr32;
82	/** 64bit version of the ELF section header. */
83	Elf64_Sym Hdr64;
84	} ELFSYMS;
85	/** Pointer to a ELF symbol entry union. */
86	typedef ELFSYMS *PELFSYMS;
87	/** Pointer to const ELF symbol entry union. */
88	typedef ELFSYMS const *PCELFSYMS;
89
90	/**
91	* Message buffer structure.
92	*/
93	typedef union FBSDMSGBUF
94	{
95	/** 32bit version. */
96	struct
97	{
98	/** Message buffer pointer. */
99	uint32_t msg_ptr;
100	/** Magic value to identify the structure. */
101	uint32_t msg_magic;
102	/** Size of the buffer area. */
103	uint32_t msg_size;
104	/** Write sequence number. */
105	uint32_t msg_wseq;
106	/** Read sequence number. */
107	uint32_t msg_rseq;
108	/** @todo More fields which are not required atm. */
109	} Hdr32;
110	/** 64bit version. */
111	struct
112	{
113	/** Message buffer pointer. */
114	uint64_t msg_ptr;
115	/** Magic value to identify the structure. */
116	uint32_t msg_magic;
117	/** Size of the buffer area. */
118	uint32_t msg_size;
119	/** Write sequence number. */
120	uint32_t msg_wseq;
121	/** Read sequence number. */
122	uint32_t msg_rseq;
123	/** @todo More fields which are not required atm. */
124	} Hdr64;
125	} FBSDMSGBUF;
126	/** Pointer to a message buffer structure. */
127	typedef FBSDMSGBUF *PFBSDMSGBUF;
128	/** Pointer to a const message buffer structure. */
129	typedef FBSDMSGBUF const *PCFBSDMSGBUF;
130
131	/** Magic value to identify the message buffer structure. */
132	#define FBSD_MSGBUF_MAGIC UINT32_C(0x063062)
133
134	/**
135	* FreeBSD guest OS digger instance data.
136	*/
137	typedef struct DBGDIGGERFBSD
138	{
139	/** Whether the information is valid or not.
140	* (For fending off illegal interface method calls.) */
141	bool fValid;
142	/** 64-bit/32-bit indicator. */
143	bool f64Bit;
144
145	/** Address of the start of the kernel ELF image,
146	* set during probing. */
147	DBGFADDRESS AddrKernelElfStart;
148	/** Address of the interpreter content aka "/red/herring". */
149	DBGFADDRESS AddrKernelInterp;
150	/** Address of the start of the text section. */
151	DBGFADDRESS AddrKernelText;
152
153	/** The kernel message log interface. */
154	DBGFOSIDMESG IDmesg;
155
156	} DBGDIGGERFBSD;
157	/** Pointer to the FreeBSD guest OS digger instance data. */
158	typedef DBGDIGGERFBSD *PDBGDIGGERFBSD;
159
160
161	/*********************************************************************************************************************************
162	* Defined Constants And Macros *
163	*********************************************************************************************************************************/
164	/** Min kernel address (32bit). */
165	#define FBSD32_MIN_KRNL_ADDR UINT32_C(0x80000000)
166	/** Max kernel address (32bit). */
167	#define FBSD32_MAX_KRNL_ADDR UINT32_C(0xfffff000)
168
169	/** Min kernel address (64bit). */
170	#define FBSD64_MIN_KRNL_ADDR UINT64_C(0xFFFFF80000000000)
171	/** Max kernel address (64bit). */
172	#define FBSD64_MAX_KRNL_ADDR UINT64_C(0xFFFFFFFFFFF00000)
173
174
175	/** Validates a 32-bit FreeBSD kernel address */
176	#define FBSD32_VALID_ADDRESS(Addr) ( (Addr) > FBSD32_MIN_KRNL_ADDR \
177	&& (Addr) < FBSD32_MAX_KRNL_ADDR)
178	/** Validates a 64-bit FreeBSD kernel address */
179	#define FBSD64_VALID_ADDRESS(Addr) ( (Addr) > FBSD64_MIN_KRNL_ADDR \
180	&& (Addr) < FBSD64_MAX_KRNL_ADDR)
181
182	/** Validates a FreeBSD kernel address. */
183	#define FBSD_VALID_ADDRESS(a_pThis, a_Addr) ((a_pThis)->f64Bit ? FBSD64_VALID_ADDRESS(a_Addr) : FBSD32_VALID_ADDRESS(a_Addr))
184
185	/** Maximum offset from the start of the ELF image we look for the /red/herring .interp section content. */
186	#define FBSD_MAX_INTERP_OFFSET _16K
187	/** The max kernel size. */
188	#define FBSD_MAX_KERNEL_SIZE UINT32_C(0x0f000000)
189
190	/** Versioned and bitness wrapper. */
191	#define FBSD_UNION(a_pThis, a_pUnion, a_Member) ((a_pThis)->f64Bit ? (a_pUnion)->Hdr64. a_Member : (a_pUnion)->Hdr32. a_Member )
192
193
194	/*********************************************************************************************************************************
195	* Internal Functions *
196	*********************************************************************************************************************************/
197	static DECLCALLBACK(int) dbgDiggerFreeBsdInit(PUVM pUVM, void *pvData);
198
199
200	/*********************************************************************************************************************************
201	* Global Variables *
202	*********************************************************************************************************************************/
203	/** Table of common FreeBSD kernel addresses. */
204	static uint64_t g_au64FreeBsdKernelAddresses[] =
205	{
206	UINT64_C(0xc0100000),
207	UINT64_C(0xffffffff80100000)
208	};
209	/** Magic string which resides in the .interp section of the image. */
210	static const uint8_t g_abNeedleInterp[] = "/red/herring";
211
212
213	/**
214	* Load the symbols from the .dynsym and .dynstr sections given
215	* by their address in guest memory.
216	*
217	* @returns VBox status code.
218	* @param pThis The instance data.
219	* @param pUVM The user mode VM handle.
220	* @param pszName The image name.
221	* @param uKernelStart The kernel start address.
222	* @param cbKernel Size of the kernel image.
223	* @param pAddrDynsym Start address of the .dynsym section.
224	* @param cSymbols Number of symbols in the .dynsym section.
225	* @param pAddrDynstr Start address of the .dynstr section containing the symbol names.
226	* @param cbDynstr Size of the .dynstr section.
227	*/
228	static int dbgDiggerFreeBsdLoadSymbols(PDBGDIGGERFBSD pThis, PUVM pUVM, const char *pszName, RTGCUINTPTR uKernelStart,
229	size_t cbKernel, PDBGFADDRESS pAddrDynsym, uint32_t cSymbols, PDBGFADDRESS pAddrDynstr,
230	size_t cbDynstr)
231	{
232	LogFlowFunc(("pThis=%#p pszName=%s uKernelStart=%RGv cbKernel=%zu pAddrDynsym=%#p{%RGv} cSymbols=%u pAddrDynstr=%#p{%RGv} cbDynstr=%zu\n",
233	pThis, pszName, uKernelStart, cbKernel, pAddrDynsym, pAddrDynsym->FlatPtr, cSymbols, pAddrDynstr, pAddrDynstr->FlatPtr, cbDynstr));
234
235	char pbDynstr = (char )RTMemAllocZ(cbDynstr + 1); /* Extra terminator. */
236	int rc = DBGFR3MemRead(pUVM, 0 /idCpu/, pAddrDynstr, pbDynstr, cbDynstr);
237	if (RT_SUCCESS(rc))
238	{
239	uint32_t cbDynsymEnt = pThis->f64Bit ? sizeof(Elf64_Sym) : sizeof(Elf32_Sym);
240	uint8_t pbDynsym = (uint8_t )RTMemAllocZ(cSymbols * cbDynsymEnt);
241	rc = DBGFR3MemRead(pUVM, 0 /idCpu/, pAddrDynsym, pbDynsym, cSymbols * cbDynsymEnt);
242	if (RT_SUCCESS(rc))
243	{
244	/*
245	* Create a module for the kernel.
246	*/
247	RTDBGMOD hMod;
248	rc = RTDbgModCreate(&hMod, pszName, cbKernel, 0 /fFlags/);
249	if (RT_SUCCESS(rc))
250	{
251	rc = RTDbgModSetTag(hMod, DIG_FBSD_MOD_TAG); AssertRC(rc);
252	rc = VINF_SUCCESS;
253
254	/*
255	* Enumerate the symbols.
256	*/
257	uint32_t cLeft = cSymbols;
258	while (cLeft-- > 0 && RT_SUCCESS(rc))
259	{
260	PCELFSYMS pSym = (PCELFSYMS)&pbDynsym[cLeft * cbDynsymEnt];
261	uint32_t idxSymStr = FBSD_UNION(pThis, pSym, st_name);
262	uint8_t uType = FBSD_UNION(pThis, pSym, st_info);
263	RTGCUINTPTR AddrVal = FBSD_UNION(pThis, pSym, st_value);
264	size_t cbSymVal = FBSD_UNION(pThis, pSym, st_size);
265
266	/* Add it without the type char. */
267	RT_NOREF(uType);
268	if ( AddrVal <= uKernelStart + cbKernel
269	&& idxSymStr < cbDynstr)
270	{
271	rc = RTDbgModSymbolAdd(hMod, &pbDynstr[idxSymStr], RTDBGSEGIDX_RVA, AddrVal - uKernelStart,
272	cbSymVal, 0 /fFlags/, NULL);
273	if (RT_FAILURE(rc))
274	{
275	if ( rc == VERR_DBG_SYMBOL_NAME_OUT_OF_RANGE
276	\|\| rc == VERR_DBG_INVALID_RVA
277	\|\| rc == VERR_DBG_ADDRESS_CONFLICT
278	\|\| rc == VERR_DBG_DUPLICATE_SYMBOL)
279	{
280	Log2(("dbgDiggerFreeBsdLoadSymbols: RTDbgModSymbolAdd(,%s,) failed %Rrc (ignored)\n",
281	&pbDynstr[idxSymStr], rc));
282	rc = VINF_SUCCESS;
283	}
284	else
285	Log(("dbgDiggerFreeBsdLoadSymbols: RTDbgModSymbolAdd(,%s,) failed %Rrc\n",
286	&pbDynstr[idxSymStr], rc));
287	}
288	}
289	}
290
291	/*
292	* Link the module into the address space.
293	*/
294	if (RT_SUCCESS(rc))
295	{
296	RTDBGAS hAs = DBGFR3AsResolveAndRetain(pUVM, DBGF_AS_KERNEL);
297	if (hAs != NIL_RTDBGAS)
298	rc = RTDbgAsModuleLink(hAs, hMod, uKernelStart, RTDBGASLINK_FLAGS_REPLACE);
299	else
300	rc = VERR_INTERNAL_ERROR;
301	RTDbgAsRelease(hAs);
302	}
303	else
304	Log(("dbgDiggerFreeBsdLoadSymbols: Failed: %Rrc\n", rc));
305	RTDbgModRelease(hMod);
306	}
307	else
308	Log(("dbgDiggerFreeBsdLoadSymbols: RTDbgModCreate failed: %Rrc\n", rc));
309	}
310	else
311	Log(("dbgDiggerFreeBsdLoadSymbols: Reading symbol table at %RGv failed: %Rrc\n",
312	pAddrDynsym->FlatPtr, rc));
313	RTMemFree(pbDynsym);
314	}
315	else
316	Log(("dbgDiggerFreeBsdLoadSymbols: Reading symbol string table at %RGv failed: %Rrc\n",
317	pAddrDynstr->FlatPtr, rc));
318	RTMemFree(pbDynstr);
319
320	LogFlowFunc(("returns %Rrc\n", rc));
321	return rc;
322	}
323
324	/**
325	* Process the kernel image.
326	*
327	* @param pThis The instance data.
328	* @param pUVM The user mode VM handle.
329	* @param pszName The image name.
330	*/
331	static void dbgDiggerFreeBsdProcessKernelImage(PDBGDIGGERFBSD pThis, PUVM pUVM, const char *pszName)
332	{
333	/*
334	* FreeBSD has parts of the kernel ELF image in guest memory, starting with the
335	* ELF header and the content of the sections which are indicated to be loaded
336	* into memory (text, rodata, etc.) of course. Whats missing are the section headers
337	* which is understandable but unfortunate because it would make our life easier.
338	*
339	* All checked FreeBSD kernels so far have the following layout in the kernel:
340	* [.interp] - contains the /red/herring string we used for probing earlier
341	* [.hash] - contains the hashes of the symbol names, 8 byte alignment on 64bit, 4 byte on 32bit
342	* [.gnu.hash] - GNU hash section. (introduced somewhere between 10.0 and 12.0 @todo Find out when exactly)
343	* [.dynsym] - contains the ELF symbol descriptors, 8 byte alignment, 4 byte on 32bit
344	* [.dynstr] - contains the symbol names as a string table, 1 byte alignmnt
345	* [.text] - contains the executable code, 16 byte alignment.
346	*
347	* To find the start of the .dynsym and .dynstr sections we scan backwards from the start of the .text section
348	* and check for all characters allowed for symbol names and count the amount of symbols found. When the start of the
349	* .dynstr section is reached the number of entries in .dynsym is known and we can deduce the start address.
350	*
351	* This applied to the old code before the FreeBSD kernel introduced the .gnu.hash section
352	* (keeping it here for informational pruposes):
353	* The sections are always adjacent (sans alignment) so we just parse the .hash section right after
354	* .interp, ELF states that it can contain 32bit or 64bit words but all observed kernels
355	* always use 32bit words. It contains two counters at the beginning which we can use to
356	* deduct the .hash section size and the beginning of .dynsym.
357	* .dynsym contains an array of symbol descriptors which have a fixed size depending on the
358	* guest bitness.
359	* Finding the end of .dynsym is not easily doable as there is no counter available (it lives
360	* in the section headers) at this point so we just have to check whether the record is valid
361	* and if not check if it contains an ASCII string which marks the start of the .dynstr section.
362	*/
363
364	#if 0
365	DBGFADDRESS AddrInterpEnd = pThis->AddrKernelInterp;
366	DBGFR3AddrAdd(&AddrInterpEnd, sizeof(g_abNeedleInterp));
367
368	DBGFADDRESS AddrCur = pThis->AddrKernelText;
369	int rc = VINF_SUCCESS;
370	uint32_t cSymbols = 0;
371	size_t cbKernel = 512 * _1M;
372	RTGCUINTPTR uKernelStart = pThis->AddrKernelElfStart.FlatPtr;
373	FBSDPROBESTATE enmState = FBSDPROBESTATE_DYNSTR_END; /* Start searching for the end of the .dynstr section. */
374
375	while (AddrCur.FlatPtr > AddrInterpEnd.FlatPtr)
376	{
377	char achBuf[_16K];
378	size_t cbToRead = RT_MIN(sizeof(achBuf), AddrCur.FlatPtr - AddrInterpEnd.FlatPtr);
379
380	rc = DBGFR3MemRead(pUVM, 0 /idCpu/, DBGFR3AddrSub(&AddrCur, cbToRead), &achBuf[0], cbToRead);
381	if (RT_FAILURE(rc))
382	break;
383
384	for (unsigned i = cbToRead; i > 0; i--)
385	{
386	char ch = achBuf[i - 1];
387
388	switch (enmState)
389	{
390	case FBSDPROBESTATE_DYNSTR_END:
391	{
392	if (ch != '\0')
393	enmState = FBSDPROBESTATE_DYNSTR_SYM_CHAR;
394	break;
395	}
396	case FBSDPROBESTATE_DYNSTR_SYM_TERMINATOR:
397	{
398	if ( RT_C_IS_ALNUM(ch)
399	\|\| ch == '_'
400	\|\| ch == '.')
401	enmState = FBSDPROBESTATE_DYNSTR_SYM_CHAR;
402	else
403	{
404	/* Two consecutive terminator symbols mean end of .dynstr section. */
405	DBGFR3AddrAdd(&AddrCur, i);
406	DBGFADDRESS AddrDynstrStart = AddrCur;
407	DBGFADDRESS AddrDynsymStart = AddrCur;
408	DBGFR3AddrSub(&AddrDynsymStart, cSymbols * (pThis->f64Bit ? sizeof(Elf64_Sym) : sizeof(Elf64_Sym)));
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	break;
417	}
418	case FBSDPROBESTATE_DYNSTR_SYM_CHAR:
419	{
420	if ( !RT_C_IS_ALNUM(ch)
421	&& ch != '_'
422	&& ch != '.')
423	{
424	/* Non symbol character. */
425	if (ch == '\0')
426	{
427	enmState = FBSDPROBESTATE_DYNSTR_SYM_TERMINATOR;
428	cSymbols++;
429	}
430	else
431	{
432	/* Indicates the end of the .dynstr section. */
433	DBGFR3AddrAdd(&AddrCur, i);
434	DBGFADDRESS AddrDynstrStart = AddrCur;
435	DBGFADDRESS AddrDynsymStart = AddrCur;
436	DBGFR3AddrSub(&AddrDynsymStart, cSymbols * (pThis->f64Bit ? sizeof(Elf64_Sym) : sizeof(Elf32_Sym)));
437	LogFlowFunc(("Found all required section start addresses (.dynsym=%RGv cSymbols=%u, .dynstr=%RGv cb=%u)\n",
438	AddrDynsymStart.FlatPtr, cSymbols, AddrDynstrStart.FlatPtr,
439	pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr));
440	dbgDiggerFreeBsdLoadSymbols(pThis, pUVM, pszName, uKernelStart, cbKernel, &AddrDynsymStart, cSymbols, &AddrDynstrStart,
441	pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr);
442	return;
443	}
444	}
445	break;
446	}
447	default:
448	AssertFailedBreak();
449	}
450	}
451	}
452
453	LogFlow(("Failed to find valid .dynsym and .dynstr sections (%Rrc), can't load kernel symbols\n", rc));
454	#else
455	/* Calculate the start of the .hash section. */
456	DBGFADDRESS AddrHashStart = pThis->AddrKernelInterp;
457	DBGFR3AddrAdd(&AddrHashStart, sizeof(g_abNeedleInterp));
458	AddrHashStart.FlatPtr = RT_ALIGN_GCPT(AddrHashStart.FlatPtr, pThis->f64Bit ? 8 : 4, RTGCUINTPTR);
459	uint32_t au32Counters[2];
460	int rc = DBGFR3MemRead(pUVM, 0 /idCpu/, &AddrHashStart, &au32Counters[0], sizeof(au32Counters));
461	if (RT_SUCCESS(rc))
462	{
463	size_t cbHash = (au32Counters[0] + au32Counters[1] + 2) * sizeof(uint32_t);
464	if (AddrHashStart.FlatPtr + cbHash < pThis->AddrKernelText.FlatPtr) /* Should be much smaller */
465	{
466	DBGFADDRESS AddrDynsymStart = AddrHashStart;
467	uint32_t cSymbols = 0;
468	size_t cbKernel = 0;
469	RTGCUINTPTR uKernelStart = pThis->AddrKernelElfStart.FlatPtr;
470
471	DBGFR3AddrAdd(&AddrDynsymStart, cbHash);
472	AddrDynsymStart.FlatPtr = RT_ALIGN_GCPT(AddrDynsymStart.FlatPtr, pThis->f64Bit ? 8 : 4, RTGCUINTPTR);
473
474	DBGFADDRESS AddrDynstrStart = AddrDynsymStart;
475	while (AddrDynstrStart.FlatPtr < pThis->AddrKernelText.FlatPtr)
476	{
477	size_t cbDynSymEnt = pThis->f64Bit ? sizeof(Elf64_Sym) : sizeof(Elf32_Sym);
478	uint8_t abBuf[_16K];
479	size_t cbToRead = RT_MIN(sizeof(abBuf), pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr);
480
481	rc = DBGFR3MemRead(pUVM, 0 /idCpu/, &AddrDynstrStart, &abBuf[0], cbToRead);
482	if (RT_FAILURE(rc))
483	break;
484
485	for (unsigned i = 0; i < cbToRead / cbDynSymEnt; i++)
486	{
487	PCELFSYMS pSym = (PCELFSYMS)&abBuf[i * cbDynSymEnt];
488	uint32_t idxSymStr = FBSD_UNION(pThis, pSym, st_name);
489	uint8_t uType = FBSD_UNION(pThis, pSym, st_info);
490	RTGCUINTPTR AddrVal = FBSD_UNION(pThis, pSym, st_value);
491	size_t cbSymVal = FBSD_UNION(pThis, pSym, st_size);
492
493	/*
494	* If the entry doesn't look valid check whether it contains an ASCII string,
495	* we then found the start of the .dynstr section.
496	*/
497	RT_NOREF(uType);
498	if ( ELF32_ST_TYPE(uType) != STT_NOTYPE
499	&& ( !FBSD_VALID_ADDRESS(pThis, AddrVal)
500	\|\| cbSymVal > FBSD_MAX_KERNEL_SIZE
501	\|\| idxSymStr > pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr))
502	{
503	LogFlowFunc(("Invalid symbol table entry found at %RGv\n",
504	AddrDynstrStart.FlatPtr + i * cbDynSymEnt));
505
506	uint8_t pbBuf = &abBuf[i cbDynSymEnt];
507	size_t cbLeft = cbToRead - i * cbDynSymEnt;
508	/*
509	* Check to the end of the buffer whether it contains only a certain set of
510	* ASCII characters and 0 terminators.
511	*/
512	while ( cbLeft > 0
513	&& ( RT_C_IS_ALNUM(*pbBuf)
514	\|\| *pbBuf == '_'
515	\|\| *pbBuf == '\0'
516	\|\| *pbBuf == '.'))
517	{
518	cbLeft--;
519	pbBuf++;
520	}
521
522	if (!cbLeft)
523	{
524	DBGFR3AddrAdd(&AddrDynstrStart, i * cbDynSymEnt);
525	LogFlowFunc(("Found all required section start addresses (.dynsym=%RGv cSymbols=%u, .dynstr=%RGv cb=%u)\n",
526	AddrDynsymStart.FlatPtr, cSymbols, AddrDynstrStart.FlatPtr,
527	pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr));
528	dbgDiggerFreeBsdLoadSymbols(pThis, pUVM, pszName, uKernelStart, cbKernel, &AddrDynsymStart, cSymbols, &AddrDynstrStart,
529	pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr);
530	return;
531	}
532	else
533	LogFlowFunc(("Found invalid ASCII character in .dynstr section candidate: %#x\n", *pbBuf));
534	}
535	else
536	{
537	cSymbols++;
538	if ( ELF32_ST_TYPE(uType) != STT_NOTYPE
539	&& FBSD_VALID_ADDRESS(pThis, AddrVal))
540	{
541	uKernelStart = RT_MIN(uKernelStart, AddrVal);
542	cbKernel = RT_MAX(cbKernel, AddrVal + cbSymVal - uKernelStart);
543	}
544	}
545	}
546
547	/* Don't account incomplete entries. */
548	DBGFR3AddrAdd(&AddrDynstrStart, (cbToRead / cbDynSymEnt) * cbDynSymEnt);
549	}
550	}
551	else
552	LogFlowFunc((".hash section overlaps with .text section: %zu (expected much less than %u)\n", cbHash,
553	pThis->AddrKernelText.FlatPtr - AddrHashStart.FlatPtr));
554	}
555	#endif
556	}
557
558
559	/**
560	* @interface_method_impl{DBGFOSIDMESG,pfnQueryKernelLog}
561	*/
562	static DECLCALLBACK(int) dbgDiggerFreeBsdIDmsg_QueryKernelLog(PDBGFOSIDMESG pThis, PUVM pUVM, uint32_t fFlags, uint32_t cMessages,
563	char pszBuf, size_t cbBuf, size_t pcbActual)
564	{
565	RT_NOREF1(fFlags);
566	PDBGDIGGERFBSD pData = RT_FROM_MEMBER(pThis, DBGDIGGERFBSD, IDmesg);
567
568	if (cMessages < 1)
569	return VERR_INVALID_PARAMETER;
570
571	/* Resolve the message buffer address from the msgbufp symbol. */
572	RTDBGSYMBOL SymInfo;
573	int rc = DBGFR3AsSymbolByName(pUVM, DBGF_AS_KERNEL, "kernel!msgbufp", &SymInfo, NULL);
574	if (RT_SUCCESS(rc))
575	{
576	DBGFADDRESS AddrMsgBuf;
577
578	/* Read the message buffer pointer. */
579	RTGCPTR GCPtrMsgBufP = 0;
580	rc = DBGFR3MemRead(pUVM, 0 /idCpu/, DBGFR3AddrFromFlat(pUVM, &AddrMsgBuf, SymInfo.Value),
581	&GCPtrMsgBufP, pData->f64Bit ? sizeof(uint64_t) : sizeof(uint32_t));
582	if (RT_FAILURE(rc))
583	{
584	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: failed to read msgbufp at %RGv: %Rrc\n", AddrMsgBuf.FlatPtr, rc));
585	return VERR_NOT_FOUND;
586	}
587	if (!FBSD_VALID_ADDRESS(pData, GCPtrMsgBufP))
588	{
589	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: Invalid address for msgbufp: %RGv\n", GCPtrMsgBufP));
590	return VERR_NOT_FOUND;
591	}
592
593	/* Read the structure. */
594	FBSDMSGBUF MsgBuf;
595	rc = DBGFR3MemRead(pUVM, 0 /idCpu/, DBGFR3AddrFromFlat(pUVM, &AddrMsgBuf, GCPtrMsgBufP),
596	&MsgBuf, sizeof(MsgBuf));
597	if (RT_SUCCESS(rc))
598	{
599	RTGCUINTPTR AddrBuf = FBSD_UNION(pData, &MsgBuf, msg_ptr);
600	uint32_t cbMsgBuf = FBSD_UNION(pData, &MsgBuf, msg_size);
601	uint32_t uMsgBufSeqR = FBSD_UNION(pData, &MsgBuf, msg_rseq);
602	uint32_t uMsgBufSeqW = FBSD_UNION(pData, &MsgBuf, msg_wseq);
603
604	/*
605	* Validate the structure.
606	*/
607	if ( FBSD_UNION(pData, &MsgBuf, msg_magic) != FBSD_MSGBUF_MAGIC
608	\|\| cbMsgBuf < UINT32_C(4096)
609	\|\| cbMsgBuf > 16*_1M
610	\|\| FBSD_UNION(pData, &MsgBuf, msg_rseq) > cbMsgBuf
611	\|\| FBSD_UNION(pData, &MsgBuf, msg_wseq) > cbMsgBuf
612	\|\| !FBSD_VALID_ADDRESS(pData, AddrBuf) )
613	{
614	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: Invalid MsgBuf data: msg_magic=%#x msg_size=%#x msg_rseq=%#x msg_wseq=%#x msg_ptr=%RGv\n",
615	FBSD_UNION(pData, &MsgBuf, msg_magic), cbMsgBuf, uMsgBufSeqR, uMsgBufSeqW, AddrBuf));
616	return VERR_INVALID_STATE;
617	}
618
619	/*
620	* Read the buffer.
621	*/
622	char pchMsgBuf = (char )RTMemAlloc(cbMsgBuf);
623	if (!pchMsgBuf)
624	{
625	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: Failed to allocate %#x bytes of memory for the log buffer\n",
626	cbMsgBuf));
627	return VERR_INVALID_STATE;
628	}
629	rc = DBGFR3MemRead(pUVM, 0 /idCpu/, DBGFR3AddrFromFlat(pUVM, &AddrMsgBuf, AddrBuf), pchMsgBuf, cbMsgBuf);
630	if (RT_SUCCESS(rc))
631	{
632	/*
633	* Copy it out raw.
634	*/
635	uint32_t offDst = 0;
636	if (uMsgBufSeqR < uMsgBufSeqW)
637	{
638	/* Single chunk between the read and write offsets. */
639	uint32_t cbToCopy = uMsgBufSeqW - uMsgBufSeqR;
640	if (cbToCopy < cbBuf)
641	{
642	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbToCopy);
643	pszBuf[cbToCopy] = '\0';
644	rc = VINF_SUCCESS;
645	}
646	else
647	{
648	if (cbBuf)
649	{
650	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbBuf - 1);
651	pszBuf[cbBuf - 1] = '\0';
652	}
653	rc = VERR_BUFFER_OVERFLOW;
654	}
655	offDst = cbToCopy + 1;
656	}
657	else
658	{
659	/* Two chunks, read offset to end, start to write offset. */
660	uint32_t cbFirst = cbMsgBuf - uMsgBufSeqR;
661	uint32_t cbSecond = uMsgBufSeqW;
662	if (cbFirst + cbSecond < cbBuf)
663	{
664	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbFirst);
665	memcpy(&pszBuf[cbFirst], pchMsgBuf, cbSecond);
666	offDst = cbFirst + cbSecond;
667	pszBuf[offDst++] = '\0';
668	rc = VINF_SUCCESS;
669	}
670	else
671	{
672	offDst = cbFirst + cbSecond + 1;
673	if (cbFirst < cbBuf)
674	{
675	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbFirst);
676	memcpy(&pszBuf[cbFirst], pchMsgBuf, cbBuf - cbFirst);
677	pszBuf[cbBuf - 1] = '\0';
678	}
679	else if (cbBuf)
680	{
681	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbBuf - 1);
682	pszBuf[cbBuf - 1] = '\0';
683	}
684	rc = VERR_BUFFER_OVERFLOW;
685	}
686	}
687
688	if (pcbActual)
689	*pcbActual = offDst;
690	}
691	else
692	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: Error reading %#x bytes at %RGv: %Rrc\n", cbBuf, AddrBuf, rc));
693	RTMemFree(pchMsgBuf);
694	}
695	else
696	LogFlowFunc(("Failed to read message buffer header: %Rrc\n", rc));
697	}
698
699	return rc;
700	}
701
702
703	/**
704	* @copydoc DBGFOSREG::pfnStackUnwindAssist
705	*/
706	static DECLCALLBACK(int) dbgDiggerFreeBsdStackUnwindAssist(PUVM pUVM, void *pvData, VMCPUID idCpu, PDBGFSTACKFRAME pFrame,
707	PRTDBGUNWINDSTATE pState, PCCPUMCTX pInitialCtx, RTDBGAS hAs,
708	uint64_t *puScratch)
709	{
710	RT_NOREF(pUVM, pvData, idCpu, pFrame, pState, pInitialCtx, hAs, puScratch);
711	return VINF_SUCCESS;
712	}
713
714
715	/**
716	* @copydoc DBGFOSREG::pfnQueryInterface
717	*/
718	static DECLCALLBACK(void ) dbgDiggerFreeBsdQueryInterface(PUVM pUVM, void pvData, DBGFOSINTERFACE enmIf)
719	{
720	RT_NOREF1(pUVM);
721	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
722	switch (enmIf)
723	{
724	case DBGFOSINTERFACE_DMESG:
725	return &pThis->IDmesg;
726
727	default:
728	return NULL;
729	}
730	}
731
732
733	/**
734	* @copydoc DBGFOSREG::pfnQueryVersion
735	*/
736	static DECLCALLBACK(int) dbgDiggerFreeBsdQueryVersion(PUVM pUVM, void pvData, char pszVersion, size_t cchVersion)
737	{
738	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
739	Assert(pThis->fValid); RT_NOREF(pThis);
740
741	RTDBGSYMBOL SymInfo;
742	int rc = DBGFR3AsSymbolByName(pUVM, DBGF_AS_KERNEL, "kernel!version", &SymInfo, NULL);
743	if (RT_SUCCESS(rc))
744	{
745	DBGFADDRESS AddrVersion;
746	DBGFR3AddrFromFlat(pUVM, &AddrVersion, SymInfo.Value);
747
748	rc = DBGFR3MemReadString(pUVM, 0, &AddrVersion, pszVersion, cchVersion);
749	if (RT_SUCCESS(rc))
750	{
751	char *pszEnd = RTStrEnd(pszVersion, cchVersion);
752	AssertReturn(pszEnd, VERR_BUFFER_OVERFLOW);
753	while ( pszEnd > pszVersion
754	&& RT_C_IS_SPACE(pszEnd[-1]))
755	pszEnd--;
756	*pszEnd = '\0';
757	}
758	else
759	RTStrPrintf(pszVersion, cchVersion, "DBGFR3MemReadString -> %Rrc", rc);
760	}
761
762	return rc;
763	}
764
765
766
767	/**
768	* @copydoc DBGFOSREG::pfnTerm
769	*/
770	static DECLCALLBACK(void) dbgDiggerFreeBsdTerm(PUVM pUVM, void *pvData)
771	{
772	RT_NOREF1(pUVM);
773	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
774	Assert(pThis->fValid);
775
776	RT_NOREF1(pUVM);
777
778	pThis->fValid = false;
779	}
780
781
782	/**
783	* @copydoc DBGFOSREG::pfnRefresh
784	*/
785	static DECLCALLBACK(int) dbgDiggerFreeBsdRefresh(PUVM pUVM, void *pvData)
786	{
787	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
788	NOREF(pThis);
789	Assert(pThis->fValid);
790
791	dbgDiggerFreeBsdTerm(pUVM, pvData);
792	return dbgDiggerFreeBsdInit(pUVM, pvData);
793	}
794
795
796	/**
797	* @copydoc DBGFOSREG::pfnInit
798	*/
799	static DECLCALLBACK(int) dbgDiggerFreeBsdInit(PUVM pUVM, void *pvData)
800	{
801	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
802	Assert(!pThis->fValid);
803
804	RT_NOREF1(pUVM);
805
806	dbgDiggerFreeBsdProcessKernelImage(pThis, pUVM, "kernel");
807	pThis->fValid = true;
808	return VINF_SUCCESS;
809	}
810
811
812	/**
813	* @copydoc DBGFOSREG::pfnProbe
814	*/
815	static DECLCALLBACK(bool) dbgDiggerFreeBsdProbe(PUVM pUVM, void *pvData)
816	{
817	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
818
819	/*
820	* Look for the magic ELF header near the known start addresses.
821	* If one is found look for the magic "/red/herring" string which is in the
822	* "interp" section not far away and then validate the start of the ELF header
823	* to be sure.
824	*/
825	for (unsigned i = 0; i < RT_ELEMENTS(g_au64FreeBsdKernelAddresses); i++)
826	{
827	static const uint8_t s_abNeedle[] = ELFMAG;
828	DBGFADDRESS KernelAddr;
829	DBGFR3AddrFromFlat(pUVM, &KernelAddr, g_au64FreeBsdKernelAddresses[i]);
830	DBGFADDRESS HitAddr;
831	uint32_t cbLeft = FBSD_MAX_KERNEL_SIZE;
832
833	while (cbLeft > X86_PAGE_4K_SIZE)
834	{
835	int rc = DBGFR3MemScan(pUVM, 0 /idCpu/, &KernelAddr, cbLeft, 1,
836	s_abNeedle, sizeof(s_abNeedle) - 1, &HitAddr);
837	if (RT_FAILURE(rc))
838	break;
839
840	/*
841	* Look for the magic "/red/herring" near the header and verify the basic
842	* ELF header.
843	*/
844	DBGFADDRESS HitAddrInterp;
845	rc = DBGFR3MemScan(pUVM, 0 /idCpu/, &HitAddr, FBSD_MAX_INTERP_OFFSET, 1,
846	g_abNeedleInterp, sizeof(g_abNeedleInterp), &HitAddrInterp);
847	if (RT_SUCCESS(rc))
848	{
849	union
850	{
851	uint8_t ab[2 * X86_PAGE_4K_SIZE];
852	Elf32_Ehdr Hdr32;
853	Elf64_Ehdr Hdr64;
854	} ElfHdr;
855	AssertCompileMembersSameSizeAndOffset(Elf64_Ehdr, e_ident, Elf32_Ehdr, e_ident);
856	AssertCompileMembersSameSizeAndOffset(Elf64_Ehdr, e_type, Elf32_Ehdr, e_type);
857	AssertCompileMembersSameSizeAndOffset(Elf64_Ehdr, e_machine, Elf32_Ehdr, e_machine);
858	AssertCompileMembersSameSizeAndOffset(Elf64_Ehdr, e_version, Elf32_Ehdr, e_version);
859
860	rc = DBGFR3MemRead(pUVM, 0 /idCpu/, &HitAddr, &ElfHdr.ab[0], X86_PAGE_4K_SIZE);
861	if (RT_SUCCESS(rc))
862	{
863	/* We verified the magic above already by scanning for it. */
864	if ( ( ElfHdr.Hdr32.e_ident[EI_CLASS] == ELFCLASS32
865	\|\| ElfHdr.Hdr32.e_ident[EI_CLASS] == ELFCLASS64)
866	&& ElfHdr.Hdr32.e_ident[EI_DATA] == ELFDATA2LSB
867	&& ElfHdr.Hdr32.e_ident[EI_VERSION] == EV_CURRENT
868	&& ElfHdr.Hdr32.e_ident[EI_OSABI] == ELFOSABI_FREEBSD
869	&& ElfHdr.Hdr32.e_type == ET_EXEC
870	&& ( ElfHdr.Hdr32.e_machine == EM_386
871	\|\| ElfHdr.Hdr32.e_machine == EM_X86_64)
872	&& ElfHdr.Hdr32.e_version == EV_CURRENT)
873	{
874	pThis->f64Bit = ElfHdr.Hdr32.e_ident[EI_CLASS] == ELFCLASS64;
875	pThis->AddrKernelElfStart = HitAddr;
876	pThis->AddrKernelInterp = HitAddrInterp;
877	DBGFR3AddrFromFlat(pUVM, &pThis->AddrKernelText, FBSD_UNION(pThis, &ElfHdr, e_entry));
878	LogFunc(("Found %s FreeBSD kernel at %RGv (.interp section at %RGv, .text section at %RGv)\n",
879	pThis->f64Bit ? "amd64" : "i386", pThis->AddrKernelElfStart.FlatPtr,
880	pThis->AddrKernelInterp.FlatPtr, pThis->AddrKernelText.FlatPtr));
881	return true;
882	}
883	}
884	}
885
886	/*
887	* Advance.
888	*/
889	RTGCUINTPTR cbDistance = HitAddr.FlatPtr - KernelAddr.FlatPtr + sizeof(s_abNeedle) - 1;
890	if (RT_UNLIKELY(cbDistance >= cbLeft))
891	break;
892
893	cbLeft -= cbDistance;
894	DBGFR3AddrAdd(&KernelAddr, cbDistance);
895	}
896	}
897	return false;
898	}
899
900
901	/**
902	* @copydoc DBGFOSREG::pfnDestruct
903	*/
904	static DECLCALLBACK(void) dbgDiggerFreeBsdDestruct(PUVM pUVM, void *pvData)
905	{
906	RT_NOREF2(pUVM, pvData);
907	}
908
909
910	/**
911	* @copydoc DBGFOSREG::pfnConstruct
912	*/
913	static DECLCALLBACK(int) dbgDiggerFreeBsdConstruct(PUVM pUVM, void *pvData)
914	{
915	RT_NOREF1(pUVM);
916	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
917
918	pThis->fValid = false;
919	pThis->f64Bit = false;
920	pThis->IDmesg.u32Magic = DBGFOSIDMESG_MAGIC;
921	pThis->IDmesg.pfnQueryKernelLog = dbgDiggerFreeBsdIDmsg_QueryKernelLog;
922	pThis->IDmesg.u32EndMagic = DBGFOSIDMESG_MAGIC;
923
924	return VINF_SUCCESS;
925	}
926
927
928	const DBGFOSREG g_DBGDiggerFreeBsd =
929	{
930	/* .u32Magic = */ DBGFOSREG_MAGIC,
931	/* .fFlags = */ 0,
932	/* .cbData = */ sizeof(DBGDIGGERFBSD),
933	/* .szName = */ "FreeBSD",
934	/* .pfnConstruct = */ dbgDiggerFreeBsdConstruct,
935	/* .pfnDestruct = */ dbgDiggerFreeBsdDestruct,
936	/* .pfnProbe = */ dbgDiggerFreeBsdProbe,
937	/* .pfnInit = */ dbgDiggerFreeBsdInit,
938	/* .pfnRefresh = */ dbgDiggerFreeBsdRefresh,
939	/* .pfnTerm = */ dbgDiggerFreeBsdTerm,
940	/* .pfnQueryVersion = */ dbgDiggerFreeBsdQueryVersion,
941	/* .pfnQueryInterface = */ dbgDiggerFreeBsdQueryInterface,
942	/* .pfnStackUnwindAssist = */ dbgDiggerFreeBsdStackUnwindAssist,
943	/* .u32EndMagic = */ DBGFOSREG_MAGIC
944	};
945

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source: vbox/trunk/src/VBox/Debugger/DBGPlugInFreeBsd.cpp@ 78376

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