DBGPlugInFreeBsd.cpp@ 95638

Last change on this file since 95638 was 93485, checked in by vboxsync, 3 years ago
Debugger,Main: Doxygen fixes. bugref:10074
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1	/* $Id: DBGPlugInFreeBsd.cpp 93485 2022-01-29 12:32:20Z vboxsync $ */
2	/** @file
3	* DBGPlugInFreeBsd - Debugger and Guest OS Digger Plugin For FreeBSD.
4	*/
5
6	/*
7	* Copyright (C) 2016-2022 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/vmmr3vtable.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, PCVMMR3VTABLE pVMM, 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 pVMM The VMM function table.
221	* @param pszName The image name.
222	* @param uKernelStart The kernel start address.
223	* @param cbKernel Size of the kernel image.
224	* @param pAddrDynsym Start address of the .dynsym section.
225	* @param cSymbols Number of symbols in the .dynsym section.
226	* @param pAddrDynstr Start address of the .dynstr section containing the symbol names.
227	* @param cbDynstr Size of the .dynstr section.
228	*/
229	static int dbgDiggerFreeBsdLoadSymbols(PDBGDIGGERFBSD pThis, PUVM pUVM, PCVMMR3VTABLE pVMM, const char *pszName,
230	RTGCUINTPTR uKernelStart, size_t cbKernel, PDBGFADDRESS pAddrDynsym, uint32_t cSymbols,
231	PDBGFADDRESS pAddrDynstr, size_t cbDynstr)
232	{
233	LogFlowFunc(("pThis=%#p pszName=%s uKernelStart=%RGv cbKernel=%zu pAddrDynsym=%#p{%RGv} cSymbols=%u pAddrDynstr=%#p{%RGv} cbDynstr=%zu\n",
234	pThis, pszName, uKernelStart, cbKernel, pAddrDynsym, pAddrDynsym->FlatPtr, cSymbols, pAddrDynstr, pAddrDynstr->FlatPtr, cbDynstr));
235
236	char pbDynstr = (char )RTMemAllocZ(cbDynstr + 1); /* Extra terminator. */
237	int rc = pVMM->pfnDBGFR3MemRead(pUVM, 0 /idCpu/, pAddrDynstr, pbDynstr, cbDynstr);
238	if (RT_SUCCESS(rc))
239	{
240	uint32_t cbDynsymEnt = pThis->f64Bit ? sizeof(Elf64_Sym) : sizeof(Elf32_Sym);
241	uint8_t pbDynsym = (uint8_t )RTMemAllocZ(cSymbols * cbDynsymEnt);
242	rc = pVMM->pfnDBGFR3MemRead(pUVM, 0 /idCpu/, pAddrDynsym, pbDynsym, cSymbols * cbDynsymEnt);
243	if (RT_SUCCESS(rc))
244	{
245	/*
246	* Create a module for the kernel.
247	*/
248	RTDBGMOD hMod;
249	rc = RTDbgModCreate(&hMod, pszName, cbKernel, 0 /fFlags/);
250	if (RT_SUCCESS(rc))
251	{
252	rc = RTDbgModSetTag(hMod, DIG_FBSD_MOD_TAG); AssertRC(rc);
253	rc = VINF_SUCCESS;
254
255	/*
256	* Enumerate the symbols.
257	*/
258	uint32_t cLeft = cSymbols;
259	while (cLeft-- > 0 && RT_SUCCESS(rc))
260	{
261	PCELFSYMS pSym = (PCELFSYMS)&pbDynsym[cLeft * cbDynsymEnt];
262	uint32_t idxSymStr = FBSD_UNION(pThis, pSym, st_name);
263	uint8_t uType = FBSD_UNION(pThis, pSym, st_info);
264	RTGCUINTPTR AddrVal = FBSD_UNION(pThis, pSym, st_value);
265	size_t cbSymVal = FBSD_UNION(pThis, pSym, st_size);
266
267	/* Add it without the type char. */
268	RT_NOREF(uType);
269	if ( AddrVal <= uKernelStart + cbKernel
270	&& idxSymStr < cbDynstr)
271	{
272	rc = RTDbgModSymbolAdd(hMod, &pbDynstr[idxSymStr], RTDBGSEGIDX_RVA, AddrVal - uKernelStart,
273	cbSymVal, 0 /fFlags/, NULL);
274	if (RT_FAILURE(rc))
275	{
276	if ( rc == VERR_DBG_SYMBOL_NAME_OUT_OF_RANGE
277	\|\| rc == VERR_DBG_INVALID_RVA
278	\|\| rc == VERR_DBG_ADDRESS_CONFLICT
279	\|\| rc == VERR_DBG_DUPLICATE_SYMBOL)
280	{
281	Log2(("dbgDiggerFreeBsdLoadSymbols: RTDbgModSymbolAdd(,%s,) failed %Rrc (ignored)\n",
282	&pbDynstr[idxSymStr], rc));
283	rc = VINF_SUCCESS;
284	}
285	else
286	Log(("dbgDiggerFreeBsdLoadSymbols: RTDbgModSymbolAdd(,%s,) failed %Rrc\n",
287	&pbDynstr[idxSymStr], rc));
288	}
289	}
290	}
291
292	/*
293	* Link the module into the address space.
294	*/
295	if (RT_SUCCESS(rc))
296	{
297	RTDBGAS hAs = pVMM->pfnDBGFR3AsResolveAndRetain(pUVM, DBGF_AS_KERNEL);
298	if (hAs != NIL_RTDBGAS)
299	rc = RTDbgAsModuleLink(hAs, hMod, uKernelStart, RTDBGASLINK_FLAGS_REPLACE);
300	else
301	rc = VERR_INTERNAL_ERROR;
302	RTDbgAsRelease(hAs);
303	}
304	else
305	Log(("dbgDiggerFreeBsdLoadSymbols: Failed: %Rrc\n", rc));
306	RTDbgModRelease(hMod);
307	}
308	else
309	Log(("dbgDiggerFreeBsdLoadSymbols: RTDbgModCreate failed: %Rrc\n", rc));
310	}
311	else
312	Log(("dbgDiggerFreeBsdLoadSymbols: Reading symbol table at %RGv failed: %Rrc\n",
313	pAddrDynsym->FlatPtr, rc));
314	RTMemFree(pbDynsym);
315	}
316	else
317	Log(("dbgDiggerFreeBsdLoadSymbols: Reading symbol string table at %RGv failed: %Rrc\n",
318	pAddrDynstr->FlatPtr, rc));
319	RTMemFree(pbDynstr);
320
321	LogFlowFunc(("returns %Rrc\n", rc));
322	return rc;
323	}
324
325	/**
326	* Process the kernel image.
327	*
328	* @param pThis The instance data.
329	* @param pUVM The user mode VM handle.
330	* @param pVMM The VMM function table.
331	* @param pszName The image name.
332	*/
333	static void dbgDiggerFreeBsdProcessKernelImage(PDBGDIGGERFBSD pThis, PUVM pUVM, PCVMMR3VTABLE pVMM, const char *pszName)
334	{
335	/*
336	* FreeBSD has parts of the kernel ELF image in guest memory, starting with the
337	* ELF header and the content of the sections which are indicated to be loaded
338	* into memory (text, rodata, etc.) of course. Whats missing are the section headers
339	* which is understandable but unfortunate because it would make our life easier.
340	*
341	* All checked FreeBSD kernels so far have the following layout in the kernel:
342	* [.interp] - contains the /red/herring string we used for probing earlier
343	* [.hash] - contains the hashes of the symbol names, 8 byte alignment on 64bit, 4 byte on 32bit
344	* [.gnu.hash] - GNU hash section. (introduced somewhere between 10.0 and 12.0 @todo Find out when exactly)
345	* [.dynsym] - contains the ELF symbol descriptors, 8 byte alignment, 4 byte on 32bit
346	* [.dynstr] - contains the symbol names as a string table, 1 byte alignmnt
347	* [.text] - contains the executable code, 16 byte alignment.
348	*
349	* To find the start of the .dynsym and .dynstr sections we scan backwards from the start of the .text section
350	* and check for all characters allowed for symbol names and count the amount of symbols found. When the start of the
351	* .dynstr section is reached the number of entries in .dynsym is known and we can deduce the start address.
352	*
353	* This applied to the old code before the FreeBSD kernel introduced the .gnu.hash section
354	* (keeping it here for informational pruposes):
355	* The sections are always adjacent (sans alignment) so we just parse the .hash section right after
356	* .interp, ELF states that it can contain 32bit or 64bit words but all observed kernels
357	* always use 32bit words. It contains two counters at the beginning which we can use to
358	* deduct the .hash section size and the beginning of .dynsym.
359	* .dynsym contains an array of symbol descriptors which have a fixed size depending on the
360	* guest bitness.
361	* Finding the end of .dynsym is not easily doable as there is no counter available (it lives
362	* in the section headers) at this point so we just have to check whether the record is valid
363	* and if not check if it contains an ASCII string which marks the start of the .dynstr section.
364	*/
365
366	#if 0
367	DBGFADDRESS AddrInterpEnd = pThis->AddrKernelInterp;
368	DBGFR3AddrAdd(&AddrInterpEnd, sizeof(g_abNeedleInterp));
369
370	DBGFADDRESS AddrCur = pThis->AddrKernelText;
371	int rc = VINF_SUCCESS;
372	uint32_t cSymbols = 0;
373	size_t cbKernel = 512 * _1M;
374	RTGCUINTPTR uKernelStart = pThis->AddrKernelElfStart.FlatPtr;
375	FBSDPROBESTATE enmState = FBSDPROBESTATE_DYNSTR_END; /* Start searching for the end of the .dynstr section. */
376
377	while (AddrCur.FlatPtr > AddrInterpEnd.FlatPtr)
378	{
379	char achBuf[_16K];
380	size_t cbToRead = RT_MIN(sizeof(achBuf), AddrCur.FlatPtr - AddrInterpEnd.FlatPtr);
381
382	rc = pVMM->pfnDBGFR3MemRead(pUVM, 0 /idCpu/, pVMM->pfnDBGFR3AddrSub(&AddrCur, cbToRead), &achBuf[0], cbToRead);
383	if (RT_FAILURE(rc))
384	break;
385
386	for (unsigned i = cbToRead; i > 0; i--)
387	{
388	char ch = achBuf[i - 1];
389
390	switch (enmState)
391	{
392	case FBSDPROBESTATE_DYNSTR_END:
393	{
394	if (ch != '\0')
395	enmState = FBSDPROBESTATE_DYNSTR_SYM_CHAR;
396	break;
397	}
398	case FBSDPROBESTATE_DYNSTR_SYM_TERMINATOR:
399	{
400	if ( RT_C_IS_ALNUM(ch)
401	\|\| ch == '_'
402	\|\| ch == '.')
403	enmState = FBSDPROBESTATE_DYNSTR_SYM_CHAR;
404	else
405	{
406	/* Two consecutive terminator symbols mean end of .dynstr section. */
407	pVMM->pfnDBGFR3AddrAdd(&AddrCur, i);
408	DBGFADDRESS AddrDynstrStart = AddrCur;
409	DBGFADDRESS AddrDynsymStart = AddrCur;
410	pVMM->pfnDBGFR3AddrSub(&AddrDynsymStart, cSymbols * (pThis->f64Bit ? sizeof(Elf64_Sym) : sizeof(Elf64_Sym)));
411	LogFlowFunc(("Found all required section start addresses (.dynsym=%RGv cSymbols=%u, .dynstr=%RGv cb=%u)\n",
412	AddrDynsymStart.FlatPtr, cSymbols, AddrDynstrStart.FlatPtr,
413	pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr));
414	dbgDiggerFreeBsdLoadSymbols(pThis, pUVM, pVMM, pszName, uKernelStart, cbKernel,
415	&AddrDynsymStart, cSymbols, &AddrDynstrStart,
416	pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr);
417	return;
418	}
419	break;
420	}
421	case FBSDPROBESTATE_DYNSTR_SYM_CHAR:
422	{
423	if ( !RT_C_IS_ALNUM(ch)
424	&& ch != '_'
425	&& ch != '.')
426	{
427	/* Non symbol character. */
428	if (ch == '\0')
429	{
430	enmState = FBSDPROBESTATE_DYNSTR_SYM_TERMINATOR;
431	cSymbols++;
432	}
433	else
434	{
435	/* Indicates the end of the .dynstr section. */
436	pVMM->pfnDBGFR3AddrAdd(&AddrCur, i);
437	DBGFADDRESS AddrDynstrStart = AddrCur;
438	DBGFADDRESS AddrDynsymStart = AddrCur;
439	pVMM->pfnDBGFR3AddrSub(&AddrDynsymStart, cSymbols * (pThis->f64Bit ? sizeof(Elf64_Sym) : sizeof(Elf32_Sym)));
440	LogFlowFunc(("Found all required section start addresses (.dynsym=%RGv cSymbols=%u, .dynstr=%RGv cb=%u)\n",
441	AddrDynsymStart.FlatPtr, cSymbols, AddrDynstrStart.FlatPtr,
442	pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr));
443	dbgDiggerFreeBsdLoadSymbols(pThis, pUVM, pVMM, pszName, uKernelStart, cbKernel,
444	&AddrDynsymStart, cSymbols, &AddrDynstrStart,
445	pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr);
446	return;
447	}
448	}
449	break;
450	}
451	default:
452	AssertFailedBreak();
453	}
454	}
455	}
456
457	LogFlow(("Failed to find valid .dynsym and .dynstr sections (%Rrc), can't load kernel symbols\n", rc));
458	#else
459	/* Calculate the start of the .hash section. */
460	DBGFADDRESS AddrHashStart = pThis->AddrKernelInterp;
461	pVMM->pfnDBGFR3AddrAdd(&AddrHashStart, sizeof(g_abNeedleInterp));
462	AddrHashStart.FlatPtr = RT_ALIGN_GCPT(AddrHashStart.FlatPtr, pThis->f64Bit ? 8 : 4, RTGCUINTPTR);
463	uint32_t au32Counters[2];
464	int rc = pVMM->pfnDBGFR3MemRead(pUVM, 0 /idCpu/, &AddrHashStart, &au32Counters[0], sizeof(au32Counters));
465	if (RT_SUCCESS(rc))
466	{
467	size_t cbHash = (au32Counters[0] + au32Counters[1] + 2) * sizeof(uint32_t);
468	if (AddrHashStart.FlatPtr + cbHash < pThis->AddrKernelText.FlatPtr) /* Should be much smaller */
469	{
470	DBGFADDRESS AddrDynsymStart = AddrHashStart;
471	uint32_t cSymbols = 0;
472	size_t cbKernel = 0;
473	RTGCUINTPTR uKernelStart = pThis->AddrKernelElfStart.FlatPtr;
474
475	pVMM->pfnDBGFR3AddrAdd(&AddrDynsymStart, cbHash);
476	AddrDynsymStart.FlatPtr = RT_ALIGN_GCPT(AddrDynsymStart.FlatPtr, pThis->f64Bit ? 8 : 4, RTGCUINTPTR);
477
478	DBGFADDRESS AddrDynstrStart = AddrDynsymStart;
479	while (AddrDynstrStart.FlatPtr < pThis->AddrKernelText.FlatPtr)
480	{
481	size_t cbDynSymEnt = pThis->f64Bit ? sizeof(Elf64_Sym) : sizeof(Elf32_Sym);
482	uint8_t abBuf[_16K];
483	size_t cbToRead = RT_MIN(sizeof(abBuf), pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr);
484
485	rc = pVMM->pfnDBGFR3MemRead(pUVM, 0 /idCpu/, &AddrDynstrStart, &abBuf[0], cbToRead);
486	if (RT_FAILURE(rc))
487	break;
488
489	for (unsigned i = 0; i < cbToRead / cbDynSymEnt; i++)
490	{
491	PCELFSYMS pSym = (PCELFSYMS)&abBuf[i * cbDynSymEnt];
492	uint32_t idxSymStr = FBSD_UNION(pThis, pSym, st_name);
493	uint8_t uType = FBSD_UNION(pThis, pSym, st_info);
494	RTGCUINTPTR AddrVal = FBSD_UNION(pThis, pSym, st_value);
495	size_t cbSymVal = FBSD_UNION(pThis, pSym, st_size);
496
497	/*
498	* If the entry doesn't look valid check whether it contains an ASCII string,
499	* we then found the start of the .dynstr section.
500	*/
501	RT_NOREF(uType);
502	if ( ELF32_ST_TYPE(uType) != STT_NOTYPE
503	&& ( !FBSD_VALID_ADDRESS(pThis, AddrVal)
504	\|\| cbSymVal > FBSD_MAX_KERNEL_SIZE
505	\|\| idxSymStr > pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr))
506	{
507	LogFlowFunc(("Invalid symbol table entry found at %RGv\n",
508	AddrDynstrStart.FlatPtr + i * cbDynSymEnt));
509
510	uint8_t pbBuf = &abBuf[i cbDynSymEnt];
511	size_t cbLeft = cbToRead - i * cbDynSymEnt;
512	/*
513	* Check to the end of the buffer whether it contains only a certain set of
514	* ASCII characters and 0 terminators.
515	*/
516	while ( cbLeft > 0
517	&& ( RT_C_IS_ALNUM(*pbBuf)
518	\|\| *pbBuf == '_'
519	\|\| *pbBuf == '\0'
520	\|\| *pbBuf == '.'))
521	{
522	cbLeft--;
523	pbBuf++;
524	}
525
526	if (!cbLeft)
527	{
528	pVMM->pfnDBGFR3AddrAdd(&AddrDynstrStart, i * cbDynSymEnt);
529	LogFlowFunc(("Found all required section start addresses (.dynsym=%RGv cSymbols=%u, .dynstr=%RGv cb=%u)\n",
530	AddrDynsymStart.FlatPtr, cSymbols, AddrDynstrStart.FlatPtr,
531	pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr));
532	dbgDiggerFreeBsdLoadSymbols(pThis, pUVM, pVMM, pszName, uKernelStart, cbKernel,
533	&AddrDynsymStart, cSymbols, &AddrDynstrStart,
534	pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr);
535	return;
536	}
537	else
538	LogFlowFunc(("Found invalid ASCII character in .dynstr section candidate: %#x\n", *pbBuf));
539	}
540	else
541	{
542	cSymbols++;
543	if ( ELF32_ST_TYPE(uType) != STT_NOTYPE
544	&& FBSD_VALID_ADDRESS(pThis, AddrVal))
545	{
546	uKernelStart = RT_MIN(uKernelStart, AddrVal);
547	cbKernel = RT_MAX(cbKernel, AddrVal + cbSymVal - uKernelStart);
548	}
549	}
550	}
551
552	/* Don't account incomplete entries. */
553	pVMM->pfnDBGFR3AddrAdd(&AddrDynstrStart, (cbToRead / cbDynSymEnt) * cbDynSymEnt);
554	}
555	}
556	else
557	LogFlowFunc((".hash section overlaps with .text section: %zu (expected much less than %u)\n", cbHash,
558	pThis->AddrKernelText.FlatPtr - AddrHashStart.FlatPtr));
559	}
560	#endif
561	}
562
563
564	/**
565	* @interface_method_impl{DBGFOSIDMESG,pfnQueryKernelLog}
566	*/
567	static DECLCALLBACK(int) dbgDiggerFreeBsdIDmsg_QueryKernelLog(PDBGFOSIDMESG pThis, PUVM pUVM, PCVMMR3VTABLE pVMM, uint32_t fFlags,
568	uint32_t cMessages, char pszBuf, size_t cbBuf, size_t pcbActual)
569	{
570	PDBGDIGGERFBSD pData = RT_FROM_MEMBER(pThis, DBGDIGGERFBSD, IDmesg);
571	RT_NOREF(fFlags);
572
573	if (cMessages < 1)
574	return VERR_INVALID_PARAMETER;
575
576	/* Resolve the message buffer address from the msgbufp symbol. */
577	RTDBGSYMBOL SymInfo;
578	int rc = pVMM->pfnDBGFR3AsSymbolByName(pUVM, DBGF_AS_KERNEL, "kernel!msgbufp", &SymInfo, NULL);
579	if (RT_SUCCESS(rc))
580	{
581	DBGFADDRESS AddrMsgBuf;
582
583	/* Read the message buffer pointer. */
584	RTGCPTR GCPtrMsgBufP = 0;
585	rc = pVMM->pfnDBGFR3MemRead(pUVM, 0 /idCpu/, pVMM->pfnDBGFR3AddrFromFlat(pUVM, &AddrMsgBuf, SymInfo.Value),
586	&GCPtrMsgBufP, pData->f64Bit ? sizeof(uint64_t) : sizeof(uint32_t));
587	if (RT_FAILURE(rc))
588	{
589	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: failed to read msgbufp at %RGv: %Rrc\n", AddrMsgBuf.FlatPtr, rc));
590	return VERR_NOT_FOUND;
591	}
592	if (!FBSD_VALID_ADDRESS(pData, GCPtrMsgBufP))
593	{
594	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: Invalid address for msgbufp: %RGv\n", GCPtrMsgBufP));
595	return VERR_NOT_FOUND;
596	}
597
598	/* Read the structure. */
599	FBSDMSGBUF MsgBuf;
600	rc = pVMM->pfnDBGFR3MemRead(pUVM, 0 /idCpu/, pVMM->pfnDBGFR3AddrFromFlat(pUVM, &AddrMsgBuf, GCPtrMsgBufP),
601	&MsgBuf, sizeof(MsgBuf));
602	if (RT_SUCCESS(rc))
603	{
604	RTGCUINTPTR AddrBuf = FBSD_UNION(pData, &MsgBuf, msg_ptr);
605	uint32_t cbMsgBuf = FBSD_UNION(pData, &MsgBuf, msg_size);
606	uint32_t uMsgBufSeqR = FBSD_UNION(pData, &MsgBuf, msg_rseq);
607	uint32_t uMsgBufSeqW = FBSD_UNION(pData, &MsgBuf, msg_wseq);
608
609	/*
610	* Validate the structure.
611	*/
612	if ( FBSD_UNION(pData, &MsgBuf, msg_magic) != FBSD_MSGBUF_MAGIC
613	\|\| cbMsgBuf < UINT32_C(4096)
614	\|\| cbMsgBuf > 16*_1M
615	\|\| FBSD_UNION(pData, &MsgBuf, msg_rseq) > cbMsgBuf
616	\|\| FBSD_UNION(pData, &MsgBuf, msg_wseq) > cbMsgBuf
617	\|\| !FBSD_VALID_ADDRESS(pData, AddrBuf) )
618	{
619	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: Invalid MsgBuf data: msg_magic=%#x msg_size=%#x msg_rseq=%#x msg_wseq=%#x msg_ptr=%RGv\n",
620	FBSD_UNION(pData, &MsgBuf, msg_magic), cbMsgBuf, uMsgBufSeqR, uMsgBufSeqW, AddrBuf));
621	return VERR_INVALID_STATE;
622	}
623
624	/*
625	* Read the buffer.
626	*/
627	char pchMsgBuf = (char )RTMemAlloc(cbMsgBuf);
628	if (!pchMsgBuf)
629	{
630	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: Failed to allocate %#x bytes of memory for the log buffer\n",
631	cbMsgBuf));
632	return VERR_INVALID_STATE;
633	}
634	rc = pVMM->pfnDBGFR3MemRead(pUVM, 0 /idCpu/, pVMM->pfnDBGFR3AddrFromFlat(pUVM, &AddrMsgBuf, AddrBuf),
635	pchMsgBuf, cbMsgBuf);
636	if (RT_SUCCESS(rc))
637	{
638	/*
639	* Copy it out raw.
640	*/
641	uint32_t offDst = 0;
642	if (uMsgBufSeqR < uMsgBufSeqW)
643	{
644	/* Single chunk between the read and write offsets. */
645	uint32_t cbToCopy = uMsgBufSeqW - uMsgBufSeqR;
646	if (cbToCopy < cbBuf)
647	{
648	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbToCopy);
649	pszBuf[cbToCopy] = '\0';
650	rc = VINF_SUCCESS;
651	}
652	else
653	{
654	if (cbBuf)
655	{
656	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbBuf - 1);
657	pszBuf[cbBuf - 1] = '\0';
658	}
659	rc = VERR_BUFFER_OVERFLOW;
660	}
661	offDst = cbToCopy + 1;
662	}
663	else
664	{
665	/* Two chunks, read offset to end, start to write offset. */
666	uint32_t cbFirst = cbMsgBuf - uMsgBufSeqR;
667	uint32_t cbSecond = uMsgBufSeqW;
668	if (cbFirst + cbSecond < cbBuf)
669	{
670	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbFirst);
671	memcpy(&pszBuf[cbFirst], pchMsgBuf, cbSecond);
672	offDst = cbFirst + cbSecond;
673	pszBuf[offDst++] = '\0';
674	rc = VINF_SUCCESS;
675	}
676	else
677	{
678	offDst = cbFirst + cbSecond + 1;
679	if (cbFirst < cbBuf)
680	{
681	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbFirst);
682	memcpy(&pszBuf[cbFirst], pchMsgBuf, cbBuf - cbFirst);
683	pszBuf[cbBuf - 1] = '\0';
684	}
685	else if (cbBuf)
686	{
687	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbBuf - 1);
688	pszBuf[cbBuf - 1] = '\0';
689	}
690	rc = VERR_BUFFER_OVERFLOW;
691	}
692	}
693
694	if (pcbActual)
695	*pcbActual = offDst;
696	}
697	else
698	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: Error reading %#x bytes at %RGv: %Rrc\n", cbBuf, AddrBuf, rc));
699	RTMemFree(pchMsgBuf);
700	}
701	else
702	LogFlowFunc(("Failed to read message buffer header: %Rrc\n", rc));
703	}
704
705	return rc;
706	}
707
708
709	/**
710	* @copydoc DBGFOSREG::pfnStackUnwindAssist
711	*/
712	static DECLCALLBACK(int) dbgDiggerFreeBsdStackUnwindAssist(PUVM pUVM, PCVMMR3VTABLE pVMM, void *pvData, VMCPUID idCpu,
713	PDBGFSTACKFRAME pFrame, PRTDBGUNWINDSTATE pState,
714	PCCPUMCTX pInitialCtx, RTDBGAS hAs, uint64_t *puScratch)
715	{
716	RT_NOREF(pUVM, pVMM, pvData, idCpu, pFrame, pState, pInitialCtx, hAs, puScratch);
717	return VINF_SUCCESS;
718	}
719
720
721	/**
722	* @copydoc DBGFOSREG::pfnQueryInterface
723	*/
724	static DECLCALLBACK(void ) dbgDiggerFreeBsdQueryInterface(PUVM pUVM, PCVMMR3VTABLE pVMM, void pvData, DBGFOSINTERFACE enmIf)
725	{
726	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
727	RT_NOREF(pUVM, pVMM);
728
729	switch (enmIf)
730	{
731	case DBGFOSINTERFACE_DMESG:
732	return &pThis->IDmesg;
733
734	default:
735	return NULL;
736	}
737	}
738
739
740	/**
741	* @copydoc DBGFOSREG::pfnQueryVersion
742	*/
743	static DECLCALLBACK(int) dbgDiggerFreeBsdQueryVersion(PUVM pUVM, PCVMMR3VTABLE pVMM, void *pvData,
744	char *pszVersion, size_t cchVersion)
745	{
746	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
747	Assert(pThis->fValid); RT_NOREF(pThis);
748
749	RTDBGSYMBOL SymInfo;
750	int rc = pVMM->pfnDBGFR3AsSymbolByName(pUVM, DBGF_AS_KERNEL, "kernel!version", &SymInfo, NULL);
751	if (RT_SUCCESS(rc))
752	{
753	DBGFADDRESS AddrVersion;
754	pVMM->pfnDBGFR3AddrFromFlat(pUVM, &AddrVersion, SymInfo.Value);
755
756	rc = pVMM->pfnDBGFR3MemReadString(pUVM, 0, &AddrVersion, pszVersion, cchVersion);
757	if (RT_SUCCESS(rc))
758	{
759	char *pszEnd = RTStrEnd(pszVersion, cchVersion);
760	AssertReturn(pszEnd, VERR_BUFFER_OVERFLOW);
761	while ( pszEnd > pszVersion
762	&& RT_C_IS_SPACE(pszEnd[-1]))
763	pszEnd--;
764	*pszEnd = '\0';
765	}
766	else
767	RTStrPrintf(pszVersion, cchVersion, "DBGFR3MemReadString -> %Rrc", rc);
768	}
769
770	return rc;
771	}
772
773
774
775	/**
776	* @copydoc DBGFOSREG::pfnTerm
777	*/
778	static DECLCALLBACK(void) dbgDiggerFreeBsdTerm(PUVM pUVM, PCVMMR3VTABLE pVMM, void *pvData)
779	{
780	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
781	Assert(pThis->fValid);
782	RT_NOREF(pUVM, pVMM);
783
784	pThis->fValid = false;
785	}
786
787
788	/**
789	* @copydoc DBGFOSREG::pfnRefresh
790	*/
791	static DECLCALLBACK(int) dbgDiggerFreeBsdRefresh(PUVM pUVM, PCVMMR3VTABLE pVMM, void *pvData)
792	{
793	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
794	NOREF(pThis);
795	Assert(pThis->fValid);
796
797	dbgDiggerFreeBsdTerm(pUVM, pVMM, pvData);
798	return dbgDiggerFreeBsdInit(pUVM, pVMM, pvData);
799	}
800
801
802	/**
803	* @copydoc DBGFOSREG::pfnInit
804	*/
805	static DECLCALLBACK(int) dbgDiggerFreeBsdInit(PUVM pUVM, PCVMMR3VTABLE pVMM, void *pvData)
806	{
807	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
808	Assert(!pThis->fValid);
809
810	RT_NOREF1(pUVM);
811
812	dbgDiggerFreeBsdProcessKernelImage(pThis, pUVM, pVMM, "kernel");
813	pThis->fValid = true;
814	return VINF_SUCCESS;
815	}
816
817
818	/**
819	* @copydoc DBGFOSREG::pfnProbe
820	*/
821	static DECLCALLBACK(bool) dbgDiggerFreeBsdProbe(PUVM pUVM, PCVMMR3VTABLE pVMM, void *pvData)
822	{
823	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
824
825	/*
826	* Look for the magic ELF header near the known start addresses.
827	* If one is found look for the magic "/red/herring" string which is in the
828	* "interp" section not far away and then validate the start of the ELF header
829	* to be sure.
830	*/
831	for (unsigned i = 0; i < RT_ELEMENTS(g_au64FreeBsdKernelAddresses); i++)
832	{
833	static const uint8_t s_abNeedle[] = ELFMAG;
834	DBGFADDRESS KernelAddr;
835	pVMM->pfnDBGFR3AddrFromFlat(pUVM, &KernelAddr, g_au64FreeBsdKernelAddresses[i]);
836	DBGFADDRESS HitAddr;
837	uint32_t cbLeft = FBSD_MAX_KERNEL_SIZE;
838
839	while (cbLeft > X86_PAGE_4K_SIZE)
840	{
841	int rc = pVMM->pfnDBGFR3MemScan(pUVM, 0 /idCpu/, &KernelAddr, cbLeft, 1,
842	s_abNeedle, sizeof(s_abNeedle) - 1, &HitAddr);
843	if (RT_FAILURE(rc))
844	break;
845
846	/*
847	* Look for the magic "/red/herring" near the header and verify the basic
848	* ELF header.
849	*/
850	DBGFADDRESS HitAddrInterp;
851	rc = pVMM->pfnDBGFR3MemScan(pUVM, 0 /idCpu/, &HitAddr, FBSD_MAX_INTERP_OFFSET, 1,
852	g_abNeedleInterp, sizeof(g_abNeedleInterp), &HitAddrInterp);
853	if (RT_SUCCESS(rc))
854	{
855	union
856	{
857	uint8_t ab[2 * X86_PAGE_4K_SIZE];
858	Elf32_Ehdr Hdr32;
859	Elf64_Ehdr Hdr64;
860	} ElfHdr;
861	AssertCompileMembersSameSizeAndOffset(Elf64_Ehdr, e_ident, Elf32_Ehdr, e_ident);
862	AssertCompileMembersSameSizeAndOffset(Elf64_Ehdr, e_type, Elf32_Ehdr, e_type);
863	AssertCompileMembersSameSizeAndOffset(Elf64_Ehdr, e_machine, Elf32_Ehdr, e_machine);
864	AssertCompileMembersSameSizeAndOffset(Elf64_Ehdr, e_version, Elf32_Ehdr, e_version);
865
866	rc = pVMM->pfnDBGFR3MemRead(pUVM, 0 /idCpu/, &HitAddr, &ElfHdr.ab[0], X86_PAGE_4K_SIZE);
867	if (RT_SUCCESS(rc))
868	{
869	/* We verified the magic above already by scanning for it. */
870	if ( ( ElfHdr.Hdr32.e_ident[EI_CLASS] == ELFCLASS32
871	\|\| ElfHdr.Hdr32.e_ident[EI_CLASS] == ELFCLASS64)
872	&& ElfHdr.Hdr32.e_ident[EI_DATA] == ELFDATA2LSB
873	&& ElfHdr.Hdr32.e_ident[EI_VERSION] == EV_CURRENT
874	&& ElfHdr.Hdr32.e_ident[EI_OSABI] == ELFOSABI_FREEBSD
875	&& ElfHdr.Hdr32.e_type == ET_EXEC
876	&& ( ElfHdr.Hdr32.e_machine == EM_386
877	\|\| ElfHdr.Hdr32.e_machine == EM_X86_64)
878	&& ElfHdr.Hdr32.e_version == EV_CURRENT)
879	{
880	pThis->f64Bit = ElfHdr.Hdr32.e_ident[EI_CLASS] == ELFCLASS64;
881	pThis->AddrKernelElfStart = HitAddr;
882	pThis->AddrKernelInterp = HitAddrInterp;
883	pVMM->pfnDBGFR3AddrFromFlat(pUVM, &pThis->AddrKernelText, FBSD_UNION(pThis, &ElfHdr, e_entry));
884	LogFunc(("Found %s FreeBSD kernel at %RGv (.interp section at %RGv, .text section at %RGv)\n",
885	pThis->f64Bit ? "amd64" : "i386", pThis->AddrKernelElfStart.FlatPtr,
886	pThis->AddrKernelInterp.FlatPtr, pThis->AddrKernelText.FlatPtr));
887	return true;
888	}
889	}
890	}
891
892	/*
893	* Advance.
894	*/
895	RTGCUINTPTR cbDistance = HitAddr.FlatPtr - KernelAddr.FlatPtr + sizeof(s_abNeedle) - 1;
896	if (RT_UNLIKELY(cbDistance >= cbLeft))
897	break;
898
899	cbLeft -= cbDistance;
900	pVMM->pfnDBGFR3AddrAdd(&KernelAddr, cbDistance);
901	}
902	}
903	return false;
904	}
905
906
907	/**
908	* @copydoc DBGFOSREG::pfnDestruct
909	*/
910	static DECLCALLBACK(void) dbgDiggerFreeBsdDestruct(PUVM pUVM, PCVMMR3VTABLE pVMM, void *pvData)
911	{
912	RT_NOREF(pUVM, pVMM, pvData);
913	}
914
915
916	/**
917	* @copydoc DBGFOSREG::pfnConstruct
918	*/
919	static DECLCALLBACK(int) dbgDiggerFreeBsdConstruct(PUVM pUVM, PCVMMR3VTABLE pVMM, void *pvData)
920	{
921	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
922	RT_NOREF(pUVM, pVMM);
923
924	pThis->fValid = false;
925	pThis->f64Bit = false;
926	pThis->IDmesg.u32Magic = DBGFOSIDMESG_MAGIC;
927	pThis->IDmesg.pfnQueryKernelLog = dbgDiggerFreeBsdIDmsg_QueryKernelLog;
928	pThis->IDmesg.u32EndMagic = DBGFOSIDMESG_MAGIC;
929
930	return VINF_SUCCESS;
931	}
932
933
934	const DBGFOSREG g_DBGDiggerFreeBsd =
935	{
936	/* .u32Magic = */ DBGFOSREG_MAGIC,
937	/* .fFlags = */ 0,
938	/* .cbData = */ sizeof(DBGDIGGERFBSD),
939	/* .szName = */ "FreeBSD",
940	/* .pfnConstruct = */ dbgDiggerFreeBsdConstruct,
941	/* .pfnDestruct = */ dbgDiggerFreeBsdDestruct,
942	/* .pfnProbe = */ dbgDiggerFreeBsdProbe,
943	/* .pfnInit = */ dbgDiggerFreeBsdInit,
944	/* .pfnRefresh = */ dbgDiggerFreeBsdRefresh,
945	/* .pfnTerm = */ dbgDiggerFreeBsdTerm,
946	/* .pfnQueryVersion = */ dbgDiggerFreeBsdQueryVersion,
947	/* .pfnQueryInterface = */ dbgDiggerFreeBsdQueryInterface,
948	/* .pfnStackUnwindAssist = */ dbgDiggerFreeBsdStackUnwindAssist,
949	/* .u32EndMagic = */ DBGFOSREG_MAGIC
950	};
951

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source: vbox/trunk/src/VBox/Debugger/DBGPlugInFreeBsd.cpp@ 95638

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