DBGPlugInFreeBsd.cpp@ 104255

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1	/* $Id: DBGPlugInFreeBsd.cpp 98103 2023-01-17 14:15:46Z vboxsync $ */
2	/** @file
3	* DBGPlugInFreeBsd - Debugger and Guest OS Digger Plugin For FreeBSD.
4	*/
5
6	/*
7	* Copyright (C) 2016-2023 Oracle and/or its affiliates.
8	*
9	* This file is part of VirtualBox base platform packages, as
10	* available from https://www.virtualbox.org.
11	*
12	* This program is free software; you can redistribute it and/or
13	* modify it under the terms of the GNU General Public License
14	* as published by the Free Software Foundation, in version 3 of the
15	* License.
16	*
17	* This program is distributed in the hope that it will be useful, but
18	* WITHOUT ANY WARRANTY; without even the implied warranty of
19	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20	* General Public License for more details.
21	*
22	* You should have received a copy of the GNU General Public License
23	* along with this program; if not, see <https://www.gnu.org/licenses>.
24	*
25	* SPDX-License-Identifier: GPL-3.0-only
26	*/
27
28
29	/*********************************************************************************************************************************
30	* Header Files *
31	*********************************************************************************************************************************/
32	#define LOG_GROUP LOG_GROUP_DBGF /// @todo add new log group.
33	#include "DBGPlugIns.h"
34	#include "DBGPlugInCommonELF.h"
35	#include <VBox/vmm/vmmr3vtable.h>
36	#include <iprt/asm.h>
37	#include <iprt/ctype.h>
38	#include <iprt/err.h>
39	#include <iprt/mem.h>
40	#include <iprt/stream.h>
41	#include <iprt/string.h>
42
43
44	/*********************************************************************************************************************************
45	* Defined Constants And Macros *
46	*********************************************************************************************************************************/
47	/** FreeBSD on little endian ASCII systems. */
48	#define DIG_FBSD_MOD_TAG UINT64_C(0x0044534265657246)
49
50
51	/*********************************************************************************************************************************
52	* Structures and Typedefs *
53	*********************************************************************************************************************************/
54
55	/**
56	* FreeBSD .dynstr and .dynsym location probing state.
57	*/
58	typedef enum FBSDPROBESTATE
59	{
60	/** Invalid state. */
61	FBSDPROBESTATE_INVALID = 0,
62	/** Searching for the end of the .dynstr section (terminator). */
63	FBSDPROBESTATE_DYNSTR_END,
64	/** Last symbol was a symbol terminator character. */
65	FBSDPROBESTATE_DYNSTR_SYM_TERMINATOR,
66	/** Last symbol was a symbol character. */
67	FBSDPROBESTATE_DYNSTR_SYM_CHAR
68	} FBSDPROBESTATE;
69
70	/**
71	* ELF headers union.
72	*/
73	typedef union ELFEHDRS
74	{
75	/** 32bit version of the ELF header. */
76	Elf32_Ehdr Hdr32;
77	/** 64bit version of the ELF header. */
78	Elf64_Ehdr Hdr64;
79	} ELFEHDRS;
80	/** Pointer to a ELF header union. */
81	typedef ELFEHDRS *PELFEHDRS;
82	/** Pointer to const ELF header union. */
83	typedef ELFEHDRS const *PCELFEHDRS;
84
85	/**
86	* ELF symbol entry union.
87	*/
88	typedef union ELFSYMS
89	{
90	/** 32bit version of the ELF section header. */
91	Elf32_Sym Hdr32;
92	/** 64bit version of the ELF section header. */
93	Elf64_Sym Hdr64;
94	} ELFSYMS;
95	/** Pointer to a ELF symbol entry union. */
96	typedef ELFSYMS *PELFSYMS;
97	/** Pointer to const ELF symbol entry union. */
98	typedef ELFSYMS const *PCELFSYMS;
99
100	/**
101	* Message buffer structure.
102	*/
103	typedef union FBSDMSGBUF
104	{
105	/** 32bit version. */
106	struct
107	{
108	/** Message buffer pointer. */
109	uint32_t msg_ptr;
110	/** Magic value to identify the structure. */
111	uint32_t msg_magic;
112	/** Size of the buffer area. */
113	uint32_t msg_size;
114	/** Write sequence number. */
115	uint32_t msg_wseq;
116	/** Read sequence number. */
117	uint32_t msg_rseq;
118	/** @todo More fields which are not required atm. */
119	} Hdr32;
120	/** 64bit version. */
121	struct
122	{
123	/** Message buffer pointer. */
124	uint64_t msg_ptr;
125	/** Magic value to identify the structure. */
126	uint32_t msg_magic;
127	/** Size of the buffer area. */
128	uint32_t msg_size;
129	/** Write sequence number. */
130	uint32_t msg_wseq;
131	/** Read sequence number. */
132	uint32_t msg_rseq;
133	/** @todo More fields which are not required atm. */
134	} Hdr64;
135	} FBSDMSGBUF;
136	/** Pointer to a message buffer structure. */
137	typedef FBSDMSGBUF *PFBSDMSGBUF;
138	/** Pointer to a const message buffer structure. */
139	typedef FBSDMSGBUF const *PCFBSDMSGBUF;
140
141	/** Magic value to identify the message buffer structure. */
142	#define FBSD_MSGBUF_MAGIC UINT32_C(0x063062)
143
144	/**
145	* FreeBSD guest OS digger instance data.
146	*/
147	typedef struct DBGDIGGERFBSD
148	{
149	/** Whether the information is valid or not.
150	* (For fending off illegal interface method calls.) */
151	bool fValid;
152	/** 64-bit/32-bit indicator. */
153	bool f64Bit;
154
155	/** Address of the start of the kernel ELF image,
156	* set during probing. */
157	DBGFADDRESS AddrKernelElfStart;
158	/** Address of the interpreter content aka "/red/herring". */
159	DBGFADDRESS AddrKernelInterp;
160	/** Address of the start of the text section. */
161	DBGFADDRESS AddrKernelText;
162
163	/** The kernel message log interface. */
164	DBGFOSIDMESG IDmesg;
165
166	} DBGDIGGERFBSD;
167	/** Pointer to the FreeBSD guest OS digger instance data. */
168	typedef DBGDIGGERFBSD *PDBGDIGGERFBSD;
169
170
171	/*********************************************************************************************************************************
172	* Defined Constants And Macros *
173	*********************************************************************************************************************************/
174	/** Min kernel address (32bit). */
175	#define FBSD32_MIN_KRNL_ADDR UINT32_C(0x80000000)
176	/** Max kernel address (32bit). */
177	#define FBSD32_MAX_KRNL_ADDR UINT32_C(0xfffff000)
178
179	/** Min kernel address (64bit). */
180	#define FBSD64_MIN_KRNL_ADDR UINT64_C(0xFFFFF80000000000)
181	/** Max kernel address (64bit). */
182	#define FBSD64_MAX_KRNL_ADDR UINT64_C(0xFFFFFFFFFFF00000)
183
184
185	/** Validates a 32-bit FreeBSD kernel address */
186	#define FBSD32_VALID_ADDRESS(Addr) ( (Addr) > FBSD32_MIN_KRNL_ADDR \
187	&& (Addr) < FBSD32_MAX_KRNL_ADDR)
188	/** Validates a 64-bit FreeBSD kernel address */
189	#define FBSD64_VALID_ADDRESS(Addr) ( (Addr) > FBSD64_MIN_KRNL_ADDR \
190	&& (Addr) < FBSD64_MAX_KRNL_ADDR)
191
192	/** Validates a FreeBSD kernel address. */
193	#define FBSD_VALID_ADDRESS(a_pThis, a_Addr) ((a_pThis)->f64Bit ? FBSD64_VALID_ADDRESS(a_Addr) : FBSD32_VALID_ADDRESS(a_Addr))
194
195	/** Maximum offset from the start of the ELF image we look for the /red/herring .interp section content. */
196	#define FBSD_MAX_INTERP_OFFSET _16K
197	/** The max kernel size. */
198	#define FBSD_MAX_KERNEL_SIZE UINT32_C(0x0f000000)
199
200	/** Versioned and bitness wrapper. */
201	#define FBSD_UNION(a_pThis, a_pUnion, a_Member) ((a_pThis)->f64Bit ? (a_pUnion)->Hdr64. a_Member : (a_pUnion)->Hdr32. a_Member )
202
203
204	/*********************************************************************************************************************************
205	* Internal Functions *
206	*********************************************************************************************************************************/
207	static DECLCALLBACK(int) dbgDiggerFreeBsdInit(PUVM pUVM, PCVMMR3VTABLE pVMM, void *pvData);
208
209
210	/*********************************************************************************************************************************
211	* Global Variables *
212	*********************************************************************************************************************************/
213	/** Table of common FreeBSD kernel addresses. */
214	static uint64_t g_au64FreeBsdKernelAddresses[] =
215	{
216	UINT64_C(0xc0100000),
217	UINT64_C(0xffffffff80100000)
218	};
219	/** Magic string which resides in the .interp section of the image. */
220	static const uint8_t g_abNeedleInterp[] = "/red/herring";
221
222
223	/**
224	* Load the symbols from the .dynsym and .dynstr sections given
225	* by their address in guest memory.
226	*
227	* @returns VBox status code.
228	* @param pThis The instance data.
229	* @param pUVM The user mode VM handle.
230	* @param pVMM The VMM function table.
231	* @param pszName The image name.
232	* @param uKernelStart The kernel start address.
233	* @param cbKernel Size of the kernel image.
234	* @param pAddrDynsym Start address of the .dynsym section.
235	* @param cSymbols Number of symbols in the .dynsym section.
236	* @param pAddrDynstr Start address of the .dynstr section containing the symbol names.
237	* @param cbDynstr Size of the .dynstr section.
238	*/
239	static int dbgDiggerFreeBsdLoadSymbols(PDBGDIGGERFBSD pThis, PUVM pUVM, PCVMMR3VTABLE pVMM, const char *pszName,
240	RTGCUINTPTR uKernelStart, size_t cbKernel, PDBGFADDRESS pAddrDynsym, uint32_t cSymbols,
241	PDBGFADDRESS pAddrDynstr, size_t cbDynstr)
242	{
243	LogFlowFunc(("pThis=%#p pszName=%s uKernelStart=%RGv cbKernel=%zu pAddrDynsym=%#p{%RGv} cSymbols=%u pAddrDynstr=%#p{%RGv} cbDynstr=%zu\n",
244	pThis, pszName, uKernelStart, cbKernel, pAddrDynsym, pAddrDynsym->FlatPtr, cSymbols, pAddrDynstr, pAddrDynstr->FlatPtr, cbDynstr));
245
246	char pbDynstr = (char )RTMemAllocZ(cbDynstr + 1); /* Extra terminator. */
247	int rc = pVMM->pfnDBGFR3MemRead(pUVM, 0 /idCpu/, pAddrDynstr, pbDynstr, cbDynstr);
248	if (RT_SUCCESS(rc))
249	{
250	uint32_t cbDynsymEnt = pThis->f64Bit ? sizeof(Elf64_Sym) : sizeof(Elf32_Sym);
251	uint8_t pbDynsym = (uint8_t )RTMemAllocZ(cSymbols * cbDynsymEnt);
252	rc = pVMM->pfnDBGFR3MemRead(pUVM, 0 /idCpu/, pAddrDynsym, pbDynsym, cSymbols * cbDynsymEnt);
253	if (RT_SUCCESS(rc))
254	{
255	/*
256	* Create a module for the kernel.
257	*/
258	RTDBGMOD hMod;
259	rc = RTDbgModCreate(&hMod, pszName, cbKernel, 0 /fFlags/);
260	if (RT_SUCCESS(rc))
261	{
262	rc = RTDbgModSetTag(hMod, DIG_FBSD_MOD_TAG); AssertRC(rc);
263	rc = VINF_SUCCESS;
264
265	/*
266	* Enumerate the symbols.
267	*/
268	uint32_t cLeft = cSymbols;
269	while (cLeft-- > 0 && RT_SUCCESS(rc))
270	{
271	PCELFSYMS pSym = (PCELFSYMS)&pbDynsym[cLeft * cbDynsymEnt];
272	uint32_t idxSymStr = FBSD_UNION(pThis, pSym, st_name);
273	uint8_t uType = FBSD_UNION(pThis, pSym, st_info);
274	RTGCUINTPTR AddrVal = FBSD_UNION(pThis, pSym, st_value);
275	size_t cbSymVal = FBSD_UNION(pThis, pSym, st_size);
276
277	/* Add it without the type char. */
278	RT_NOREF(uType);
279	if ( AddrVal <= uKernelStart + cbKernel
280	&& idxSymStr < cbDynstr)
281	{
282	rc = RTDbgModSymbolAdd(hMod, &pbDynstr[idxSymStr], RTDBGSEGIDX_RVA, AddrVal - uKernelStart,
283	cbSymVal, 0 /fFlags/, NULL);
284	if (RT_FAILURE(rc))
285	{
286	if ( rc == VERR_DBG_SYMBOL_NAME_OUT_OF_RANGE
287	\|\| rc == VERR_DBG_INVALID_RVA
288	\|\| rc == VERR_DBG_ADDRESS_CONFLICT
289	\|\| rc == VERR_DBG_DUPLICATE_SYMBOL)
290	{
291	Log2(("dbgDiggerFreeBsdLoadSymbols: RTDbgModSymbolAdd(,%s,) failed %Rrc (ignored)\n",
292	&pbDynstr[idxSymStr], rc));
293	rc = VINF_SUCCESS;
294	}
295	else
296	Log(("dbgDiggerFreeBsdLoadSymbols: RTDbgModSymbolAdd(,%s,) failed %Rrc\n",
297	&pbDynstr[idxSymStr], rc));
298	}
299	}
300	}
301
302	/*
303	* Link the module into the address space.
304	*/
305	if (RT_SUCCESS(rc))
306	{
307	RTDBGAS hAs = pVMM->pfnDBGFR3AsResolveAndRetain(pUVM, DBGF_AS_KERNEL);
308	if (hAs != NIL_RTDBGAS)
309	rc = RTDbgAsModuleLink(hAs, hMod, uKernelStart, RTDBGASLINK_FLAGS_REPLACE);
310	else
311	rc = VERR_INTERNAL_ERROR;
312	RTDbgAsRelease(hAs);
313	}
314	else
315	Log(("dbgDiggerFreeBsdLoadSymbols: Failed: %Rrc\n", rc));
316	RTDbgModRelease(hMod);
317	}
318	else
319	Log(("dbgDiggerFreeBsdLoadSymbols: RTDbgModCreate failed: %Rrc\n", rc));
320	}
321	else
322	Log(("dbgDiggerFreeBsdLoadSymbols: Reading symbol table at %RGv failed: %Rrc\n",
323	pAddrDynsym->FlatPtr, rc));
324	RTMemFree(pbDynsym);
325	}
326	else
327	Log(("dbgDiggerFreeBsdLoadSymbols: Reading symbol string table at %RGv failed: %Rrc\n",
328	pAddrDynstr->FlatPtr, rc));
329	RTMemFree(pbDynstr);
330
331	LogFlowFunc(("returns %Rrc\n", rc));
332	return rc;
333	}
334
335	/**
336	* Process the kernel image.
337	*
338	* @param pThis The instance data.
339	* @param pUVM The user mode VM handle.
340	* @param pVMM The VMM function table.
341	* @param pszName The image name.
342	*/
343	static void dbgDiggerFreeBsdProcessKernelImage(PDBGDIGGERFBSD pThis, PUVM pUVM, PCVMMR3VTABLE pVMM, const char *pszName)
344	{
345	/*
346	* FreeBSD has parts of the kernel ELF image in guest memory, starting with the
347	* ELF header and the content of the sections which are indicated to be loaded
348	* into memory (text, rodata, etc.) of course. Whats missing are the section headers
349	* which is understandable but unfortunate because it would make our life easier.
350	*
351	* All checked FreeBSD kernels so far have the following layout in the kernel:
352	* [.interp] - contains the /red/herring string we used for probing earlier
353	* [.hash] - contains the hashes of the symbol names, 8 byte alignment on 64bit, 4 byte on 32bit
354	* [.gnu.hash] - GNU hash section. (introduced somewhere between 10.0 and 12.0 @todo Find out when exactly)
355	* [.dynsym] - contains the ELF symbol descriptors, 8 byte alignment, 4 byte on 32bit
356	* [.dynstr] - contains the symbol names as a string table, 1 byte alignmnt
357	* [.text] - contains the executable code, 16 byte alignment.
358	*
359	* To find the start of the .dynsym and .dynstr sections we scan backwards from the start of the .text section
360	* and check for all characters allowed for symbol names and count the amount of symbols found. When the start of the
361	* .dynstr section is reached the number of entries in .dynsym is known and we can deduce the start address.
362	*
363	* This applied to the old code before the FreeBSD kernel introduced the .gnu.hash section
364	* (keeping it here for informational pruposes):
365	* The sections are always adjacent (sans alignment) so we just parse the .hash section right after
366	* .interp, ELF states that it can contain 32bit or 64bit words but all observed kernels
367	* always use 32bit words. It contains two counters at the beginning which we can use to
368	* deduct the .hash section size and the beginning of .dynsym.
369	* .dynsym contains an array of symbol descriptors which have a fixed size depending on the
370	* guest bitness.
371	* Finding the end of .dynsym is not easily doable as there is no counter available (it lives
372	* in the section headers) at this point so we just have to check whether the record is valid
373	* and if not check if it contains an ASCII string which marks the start of the .dynstr section.
374	*/
375
376	#if 0
377	DBGFADDRESS AddrInterpEnd = pThis->AddrKernelInterp;
378	DBGFR3AddrAdd(&AddrInterpEnd, sizeof(g_abNeedleInterp));
379
380	DBGFADDRESS AddrCur = pThis->AddrKernelText;
381	int rc = VINF_SUCCESS;
382	uint32_t cSymbols = 0;
383	size_t cbKernel = 512 * _1M;
384	RTGCUINTPTR uKernelStart = pThis->AddrKernelElfStart.FlatPtr;
385	FBSDPROBESTATE enmState = FBSDPROBESTATE_DYNSTR_END; /* Start searching for the end of the .dynstr section. */
386
387	while (AddrCur.FlatPtr > AddrInterpEnd.FlatPtr)
388	{
389	char achBuf[_16K];
390	size_t cbToRead = RT_MIN(sizeof(achBuf), AddrCur.FlatPtr - AddrInterpEnd.FlatPtr);
391
392	rc = pVMM->pfnDBGFR3MemRead(pUVM, 0 /idCpu/, pVMM->pfnDBGFR3AddrSub(&AddrCur, cbToRead), &achBuf[0], cbToRead);
393	if (RT_FAILURE(rc))
394	break;
395
396	for (unsigned i = cbToRead; i > 0; i--)
397	{
398	char ch = achBuf[i - 1];
399
400	switch (enmState)
401	{
402	case FBSDPROBESTATE_DYNSTR_END:
403	{
404	if (ch != '\0')
405	enmState = FBSDPROBESTATE_DYNSTR_SYM_CHAR;
406	break;
407	}
408	case FBSDPROBESTATE_DYNSTR_SYM_TERMINATOR:
409	{
410	if ( RT_C_IS_ALNUM(ch)
411	\|\| ch == '_'
412	\|\| ch == '.')
413	enmState = FBSDPROBESTATE_DYNSTR_SYM_CHAR;
414	else
415	{
416	/* Two consecutive terminator symbols mean end of .dynstr section. */
417	pVMM->pfnDBGFR3AddrAdd(&AddrCur, i);
418	DBGFADDRESS AddrDynstrStart = AddrCur;
419	DBGFADDRESS AddrDynsymStart = AddrCur;
420	pVMM->pfnDBGFR3AddrSub(&AddrDynsymStart, cSymbols * (pThis->f64Bit ? sizeof(Elf64_Sym) : sizeof(Elf64_Sym)));
421	LogFlowFunc(("Found all required section start addresses (.dynsym=%RGv cSymbols=%u, .dynstr=%RGv cb=%u)\n",
422	AddrDynsymStart.FlatPtr, cSymbols, AddrDynstrStart.FlatPtr,
423	pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr));
424	dbgDiggerFreeBsdLoadSymbols(pThis, pUVM, pVMM, pszName, uKernelStart, cbKernel,
425	&AddrDynsymStart, cSymbols, &AddrDynstrStart,
426	pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr);
427	return;
428	}
429	break;
430	}
431	case FBSDPROBESTATE_DYNSTR_SYM_CHAR:
432	{
433	if ( !RT_C_IS_ALNUM(ch)
434	&& ch != '_'
435	&& ch != '.')
436	{
437	/* Non symbol character. */
438	if (ch == '\0')
439	{
440	enmState = FBSDPROBESTATE_DYNSTR_SYM_TERMINATOR;
441	cSymbols++;
442	}
443	else
444	{
445	/* Indicates the end of the .dynstr section. */
446	pVMM->pfnDBGFR3AddrAdd(&AddrCur, i);
447	DBGFADDRESS AddrDynstrStart = AddrCur;
448	DBGFADDRESS AddrDynsymStart = AddrCur;
449	pVMM->pfnDBGFR3AddrSub(&AddrDynsymStart, cSymbols * (pThis->f64Bit ? sizeof(Elf64_Sym) : sizeof(Elf32_Sym)));
450	LogFlowFunc(("Found all required section start addresses (.dynsym=%RGv cSymbols=%u, .dynstr=%RGv cb=%u)\n",
451	AddrDynsymStart.FlatPtr, cSymbols, AddrDynstrStart.FlatPtr,
452	pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr));
453	dbgDiggerFreeBsdLoadSymbols(pThis, pUVM, pVMM, pszName, uKernelStart, cbKernel,
454	&AddrDynsymStart, cSymbols, &AddrDynstrStart,
455	pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr);
456	return;
457	}
458	}
459	break;
460	}
461	default:
462	AssertFailedBreak();
463	}
464	}
465	}
466
467	LogFlow(("Failed to find valid .dynsym and .dynstr sections (%Rrc), can't load kernel symbols\n", rc));
468	#else
469	/* Calculate the start of the .hash section. */
470	DBGFADDRESS AddrHashStart = pThis->AddrKernelInterp;
471	pVMM->pfnDBGFR3AddrAdd(&AddrHashStart, sizeof(g_abNeedleInterp));
472	AddrHashStart.FlatPtr = RT_ALIGN_GCPT(AddrHashStart.FlatPtr, pThis->f64Bit ? 8 : 4, RTGCUINTPTR);
473	uint32_t au32Counters[2];
474	int rc = pVMM->pfnDBGFR3MemRead(pUVM, 0 /idCpu/, &AddrHashStart, &au32Counters[0], sizeof(au32Counters));
475	if (RT_SUCCESS(rc))
476	{
477	size_t cbHash = (au32Counters[0] + au32Counters[1] + 2) * sizeof(uint32_t);
478	if (AddrHashStart.FlatPtr + cbHash < pThis->AddrKernelText.FlatPtr) /* Should be much smaller */
479	{
480	DBGFADDRESS AddrDynsymStart = AddrHashStart;
481	uint32_t cSymbols = 0;
482	size_t cbKernel = 0;
483	RTGCUINTPTR uKernelStart = pThis->AddrKernelElfStart.FlatPtr;
484
485	pVMM->pfnDBGFR3AddrAdd(&AddrDynsymStart, cbHash);
486	AddrDynsymStart.FlatPtr = RT_ALIGN_GCPT(AddrDynsymStart.FlatPtr, pThis->f64Bit ? 8 : 4, RTGCUINTPTR);
487
488	DBGFADDRESS AddrDynstrStart = AddrDynsymStart;
489	while (AddrDynstrStart.FlatPtr < pThis->AddrKernelText.FlatPtr)
490	{
491	size_t cbDynSymEnt = pThis->f64Bit ? sizeof(Elf64_Sym) : sizeof(Elf32_Sym);
492	uint8_t abBuf[_16K];
493	size_t cbToRead = RT_MIN(sizeof(abBuf), pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr);
494
495	rc = pVMM->pfnDBGFR3MemRead(pUVM, 0 /idCpu/, &AddrDynstrStart, &abBuf[0], cbToRead);
496	if (RT_FAILURE(rc))
497	break;
498
499	for (unsigned i = 0; i < cbToRead / cbDynSymEnt; i++)
500	{
501	PCELFSYMS pSym = (PCELFSYMS)&abBuf[i * cbDynSymEnt];
502	uint32_t idxSymStr = FBSD_UNION(pThis, pSym, st_name);
503	uint8_t uType = FBSD_UNION(pThis, pSym, st_info);
504	RTGCUINTPTR AddrVal = FBSD_UNION(pThis, pSym, st_value);
505	size_t cbSymVal = FBSD_UNION(pThis, pSym, st_size);
506
507	/*
508	* If the entry doesn't look valid check whether it contains an ASCII string,
509	* we then found the start of the .dynstr section.
510	*/
511	RT_NOREF(uType);
512	if ( ELF32_ST_TYPE(uType) != STT_NOTYPE
513	&& ( !FBSD_VALID_ADDRESS(pThis, AddrVal)
514	\|\| cbSymVal > FBSD_MAX_KERNEL_SIZE
515	\|\| idxSymStr > pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr))
516	{
517	LogFlowFunc(("Invalid symbol table entry found at %RGv\n",
518	AddrDynstrStart.FlatPtr + i * cbDynSymEnt));
519
520	uint8_t pbBuf = &abBuf[i cbDynSymEnt];
521	size_t cbLeft = cbToRead - i * cbDynSymEnt;
522	/*
523	* Check to the end of the buffer whether it contains only a certain set of
524	* ASCII characters and 0 terminators.
525	*/
526	while ( cbLeft > 0
527	&& ( RT_C_IS_ALNUM(*pbBuf)
528	\|\| *pbBuf == '_'
529	\|\| *pbBuf == '\0'
530	\|\| *pbBuf == '.'))
531	{
532	cbLeft--;
533	pbBuf++;
534	}
535
536	if (!cbLeft)
537	{
538	pVMM->pfnDBGFR3AddrAdd(&AddrDynstrStart, i * cbDynSymEnt);
539	LogFlowFunc(("Found all required section start addresses (.dynsym=%RGv cSymbols=%u, .dynstr=%RGv cb=%u)\n",
540	AddrDynsymStart.FlatPtr, cSymbols, AddrDynstrStart.FlatPtr,
541	pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr));
542	dbgDiggerFreeBsdLoadSymbols(pThis, pUVM, pVMM, pszName, uKernelStart, cbKernel,
543	&AddrDynsymStart, cSymbols, &AddrDynstrStart,
544	pThis->AddrKernelText.FlatPtr - AddrDynstrStart.FlatPtr);
545	return;
546	}
547	else
548	LogFlowFunc(("Found invalid ASCII character in .dynstr section candidate: %#x\n", *pbBuf));
549	}
550	else
551	{
552	cSymbols++;
553	if ( ELF32_ST_TYPE(uType) != STT_NOTYPE
554	&& FBSD_VALID_ADDRESS(pThis, AddrVal))
555	{
556	uKernelStart = RT_MIN(uKernelStart, AddrVal);
557	cbKernel = RT_MAX(cbKernel, AddrVal + cbSymVal - uKernelStart);
558	}
559	}
560	}
561
562	/* Don't account incomplete entries. */
563	pVMM->pfnDBGFR3AddrAdd(&AddrDynstrStart, (cbToRead / cbDynSymEnt) * cbDynSymEnt);
564	}
565	}
566	else
567	LogFlowFunc((".hash section overlaps with .text section: %zu (expected much less than %u)\n", cbHash,
568	pThis->AddrKernelText.FlatPtr - AddrHashStart.FlatPtr));
569	}
570	#endif
571	}
572
573
574	/**
575	* @interface_method_impl{DBGFOSIDMESG,pfnQueryKernelLog}
576	*/
577	static DECLCALLBACK(int) dbgDiggerFreeBsdIDmsg_QueryKernelLog(PDBGFOSIDMESG pThis, PUVM pUVM, PCVMMR3VTABLE pVMM, uint32_t fFlags,
578	uint32_t cMessages, char pszBuf, size_t cbBuf, size_t pcbActual)
579	{
580	PDBGDIGGERFBSD pData = RT_FROM_MEMBER(pThis, DBGDIGGERFBSD, IDmesg);
581	RT_NOREF(fFlags);
582
583	if (cMessages < 1)
584	return VERR_INVALID_PARAMETER;
585
586	/* Resolve the message buffer address from the msgbufp symbol. */
587	RTDBGSYMBOL SymInfo;
588	int rc = pVMM->pfnDBGFR3AsSymbolByName(pUVM, DBGF_AS_KERNEL, "kernel!msgbufp", &SymInfo, NULL);
589	if (RT_SUCCESS(rc))
590	{
591	DBGFADDRESS AddrMsgBuf;
592
593	/* Read the message buffer pointer. */
594	RTGCPTR GCPtrMsgBufP = 0;
595	rc = pVMM->pfnDBGFR3MemRead(pUVM, 0 /idCpu/, pVMM->pfnDBGFR3AddrFromFlat(pUVM, &AddrMsgBuf, SymInfo.Value),
596	&GCPtrMsgBufP, pData->f64Bit ? sizeof(uint64_t) : sizeof(uint32_t));
597	if (RT_FAILURE(rc))
598	{
599	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: failed to read msgbufp at %RGv: %Rrc\n", AddrMsgBuf.FlatPtr, rc));
600	return VERR_NOT_FOUND;
601	}
602	if (!FBSD_VALID_ADDRESS(pData, GCPtrMsgBufP))
603	{
604	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: Invalid address for msgbufp: %RGv\n", GCPtrMsgBufP));
605	return VERR_NOT_FOUND;
606	}
607
608	/* Read the structure. */
609	FBSDMSGBUF MsgBuf;
610	rc = pVMM->pfnDBGFR3MemRead(pUVM, 0 /idCpu/, pVMM->pfnDBGFR3AddrFromFlat(pUVM, &AddrMsgBuf, GCPtrMsgBufP),
611	&MsgBuf, sizeof(MsgBuf));
612	if (RT_SUCCESS(rc))
613	{
614	RTGCUINTPTR AddrBuf = FBSD_UNION(pData, &MsgBuf, msg_ptr);
615	uint32_t cbMsgBuf = FBSD_UNION(pData, &MsgBuf, msg_size);
616	uint32_t uMsgBufSeqR = FBSD_UNION(pData, &MsgBuf, msg_rseq);
617	uint32_t uMsgBufSeqW = FBSD_UNION(pData, &MsgBuf, msg_wseq);
618
619	/*
620	* Validate the structure.
621	*/
622	if ( FBSD_UNION(pData, &MsgBuf, msg_magic) != FBSD_MSGBUF_MAGIC
623	\|\| cbMsgBuf < UINT32_C(4096)
624	\|\| cbMsgBuf > 16*_1M
625	\|\| FBSD_UNION(pData, &MsgBuf, msg_rseq) > cbMsgBuf
626	\|\| FBSD_UNION(pData, &MsgBuf, msg_wseq) > cbMsgBuf
627	\|\| !FBSD_VALID_ADDRESS(pData, AddrBuf) )
628	{
629	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: Invalid MsgBuf data: msg_magic=%#x msg_size=%#x msg_rseq=%#x msg_wseq=%#x msg_ptr=%RGv\n",
630	FBSD_UNION(pData, &MsgBuf, msg_magic), cbMsgBuf, uMsgBufSeqR, uMsgBufSeqW, AddrBuf));
631	return VERR_INVALID_STATE;
632	}
633
634	/*
635	* Read the buffer.
636	*/
637	char pchMsgBuf = (char )RTMemAlloc(cbMsgBuf);
638	if (!pchMsgBuf)
639	{
640	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: Failed to allocate %#x bytes of memory for the log buffer\n",
641	cbMsgBuf));
642	return VERR_INVALID_STATE;
643	}
644	rc = pVMM->pfnDBGFR3MemRead(pUVM, 0 /idCpu/, pVMM->pfnDBGFR3AddrFromFlat(pUVM, &AddrMsgBuf, AddrBuf),
645	pchMsgBuf, cbMsgBuf);
646	if (RT_SUCCESS(rc))
647	{
648	/*
649	* Copy it out raw.
650	*/
651	uint32_t offDst = 0;
652	if (uMsgBufSeqR < uMsgBufSeqW)
653	{
654	/* Single chunk between the read and write offsets. */
655	uint32_t cbToCopy = uMsgBufSeqW - uMsgBufSeqR;
656	if (cbToCopy < cbBuf)
657	{
658	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbToCopy);
659	pszBuf[cbToCopy] = '\0';
660	rc = VINF_SUCCESS;
661	}
662	else
663	{
664	if (cbBuf)
665	{
666	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbBuf - 1);
667	pszBuf[cbBuf - 1] = '\0';
668	}
669	rc = VERR_BUFFER_OVERFLOW;
670	}
671	offDst = cbToCopy + 1;
672	}
673	else
674	{
675	/* Two chunks, read offset to end, start to write offset. */
676	uint32_t cbFirst = cbMsgBuf - uMsgBufSeqR;
677	uint32_t cbSecond = uMsgBufSeqW;
678	if (cbFirst + cbSecond < cbBuf)
679	{
680	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbFirst);
681	memcpy(&pszBuf[cbFirst], pchMsgBuf, cbSecond);
682	offDst = cbFirst + cbSecond;
683	pszBuf[offDst++] = '\0';
684	rc = VINF_SUCCESS;
685	}
686	else
687	{
688	offDst = cbFirst + cbSecond + 1;
689	if (cbFirst < cbBuf)
690	{
691	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbFirst);
692	memcpy(&pszBuf[cbFirst], pchMsgBuf, cbBuf - cbFirst);
693	pszBuf[cbBuf - 1] = '\0';
694	}
695	else if (cbBuf)
696	{
697	memcpy(pszBuf, &pchMsgBuf[uMsgBufSeqR], cbBuf - 1);
698	pszBuf[cbBuf - 1] = '\0';
699	}
700	rc = VERR_BUFFER_OVERFLOW;
701	}
702	}
703
704	if (pcbActual)
705	*pcbActual = offDst;
706	}
707	else
708	Log(("dbgDiggerFreeBsdIDmsg_QueryKernelLog: Error reading %#x bytes at %RGv: %Rrc\n", cbBuf, AddrBuf, rc));
709	RTMemFree(pchMsgBuf);
710	}
711	else
712	LogFlowFunc(("Failed to read message buffer header: %Rrc\n", rc));
713	}
714
715	return rc;
716	}
717
718
719	/**
720	* @copydoc DBGFOSREG::pfnStackUnwindAssist
721	*/
722	static DECLCALLBACK(int) dbgDiggerFreeBsdStackUnwindAssist(PUVM pUVM, PCVMMR3VTABLE pVMM, void *pvData, VMCPUID idCpu,
723	PDBGFSTACKFRAME pFrame, PRTDBGUNWINDSTATE pState,
724	PCCPUMCTX pInitialCtx, RTDBGAS hAs, uint64_t *puScratch)
725	{
726	RT_NOREF(pUVM, pVMM, pvData, idCpu, pFrame, pState, pInitialCtx, hAs, puScratch);
727	return VINF_SUCCESS;
728	}
729
730
731	/**
732	* @copydoc DBGFOSREG::pfnQueryInterface
733	*/
734	static DECLCALLBACK(void ) dbgDiggerFreeBsdQueryInterface(PUVM pUVM, PCVMMR3VTABLE pVMM, void pvData, DBGFOSINTERFACE enmIf)
735	{
736	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
737	RT_NOREF(pUVM, pVMM);
738
739	switch (enmIf)
740	{
741	case DBGFOSINTERFACE_DMESG:
742	return &pThis->IDmesg;
743
744	default:
745	return NULL;
746	}
747	}
748
749
750	/**
751	* @copydoc DBGFOSREG::pfnQueryVersion
752	*/
753	static DECLCALLBACK(int) dbgDiggerFreeBsdQueryVersion(PUVM pUVM, PCVMMR3VTABLE pVMM, void *pvData,
754	char *pszVersion, size_t cchVersion)
755	{
756	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
757	Assert(pThis->fValid); RT_NOREF(pThis);
758
759	RTDBGSYMBOL SymInfo;
760	int rc = pVMM->pfnDBGFR3AsSymbolByName(pUVM, DBGF_AS_KERNEL, "kernel!version", &SymInfo, NULL);
761	if (RT_SUCCESS(rc))
762	{
763	DBGFADDRESS AddrVersion;
764	pVMM->pfnDBGFR3AddrFromFlat(pUVM, &AddrVersion, SymInfo.Value);
765
766	rc = pVMM->pfnDBGFR3MemReadString(pUVM, 0, &AddrVersion, pszVersion, cchVersion);
767	if (RT_SUCCESS(rc))
768	{
769	char *pszEnd = RTStrEnd(pszVersion, cchVersion);
770	AssertReturn(pszEnd, VERR_BUFFER_OVERFLOW);
771	while ( pszEnd > pszVersion
772	&& RT_C_IS_SPACE(pszEnd[-1]))
773	pszEnd--;
774	*pszEnd = '\0';
775	}
776	else
777	RTStrPrintf(pszVersion, cchVersion, "DBGFR3MemReadString -> %Rrc", rc);
778	}
779
780	return rc;
781	}
782
783
784
785	/**
786	* @copydoc DBGFOSREG::pfnTerm
787	*/
788	static DECLCALLBACK(void) dbgDiggerFreeBsdTerm(PUVM pUVM, PCVMMR3VTABLE pVMM, void *pvData)
789	{
790	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
791	Assert(pThis->fValid);
792	RT_NOREF(pUVM, pVMM);
793
794	pThis->fValid = false;
795	}
796
797
798	/**
799	* @copydoc DBGFOSREG::pfnRefresh
800	*/
801	static DECLCALLBACK(int) dbgDiggerFreeBsdRefresh(PUVM pUVM, PCVMMR3VTABLE pVMM, void *pvData)
802	{
803	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
804	NOREF(pThis);
805	Assert(pThis->fValid);
806
807	dbgDiggerFreeBsdTerm(pUVM, pVMM, pvData);
808	return dbgDiggerFreeBsdInit(pUVM, pVMM, pvData);
809	}
810
811
812	/**
813	* @copydoc DBGFOSREG::pfnInit
814	*/
815	static DECLCALLBACK(int) dbgDiggerFreeBsdInit(PUVM pUVM, PCVMMR3VTABLE pVMM, void *pvData)
816	{
817	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
818	Assert(!pThis->fValid);
819
820	RT_NOREF1(pUVM);
821
822	dbgDiggerFreeBsdProcessKernelImage(pThis, pUVM, pVMM, "kernel");
823	pThis->fValid = true;
824	return VINF_SUCCESS;
825	}
826
827
828	/**
829	* @copydoc DBGFOSREG::pfnProbe
830	*/
831	static DECLCALLBACK(bool) dbgDiggerFreeBsdProbe(PUVM pUVM, PCVMMR3VTABLE pVMM, void *pvData)
832	{
833	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
834
835	/*
836	* Look for the magic ELF header near the known start addresses.
837	* If one is found look for the magic "/red/herring" string which is in the
838	* "interp" section not far away and then validate the start of the ELF header
839	* to be sure.
840	*/
841	for (unsigned i = 0; i < RT_ELEMENTS(g_au64FreeBsdKernelAddresses); i++)
842	{
843	static const uint8_t s_abNeedle[] = ELFMAG;
844	DBGFADDRESS KernelAddr;
845	pVMM->pfnDBGFR3AddrFromFlat(pUVM, &KernelAddr, g_au64FreeBsdKernelAddresses[i]);
846	DBGFADDRESS HitAddr;
847	uint32_t cbLeft = FBSD_MAX_KERNEL_SIZE;
848
849	while (cbLeft > X86_PAGE_4K_SIZE)
850	{
851	int rc = pVMM->pfnDBGFR3MemScan(pUVM, 0 /idCpu/, &KernelAddr, cbLeft, 1,
852	s_abNeedle, sizeof(s_abNeedle) - 1, &HitAddr);
853	if (RT_FAILURE(rc))
854	break;
855
856	/*
857	* Look for the magic "/red/herring" near the header and verify the basic
858	* ELF header.
859	*/
860	DBGFADDRESS HitAddrInterp;
861	rc = pVMM->pfnDBGFR3MemScan(pUVM, 0 /idCpu/, &HitAddr, FBSD_MAX_INTERP_OFFSET, 1,
862	g_abNeedleInterp, sizeof(g_abNeedleInterp), &HitAddrInterp);
863	if (RT_SUCCESS(rc))
864	{
865	union
866	{
867	uint8_t ab[2 * X86_PAGE_4K_SIZE];
868	Elf32_Ehdr Hdr32;
869	Elf64_Ehdr Hdr64;
870	} ElfHdr;
871	AssertCompileMembersSameSizeAndOffset(Elf64_Ehdr, e_ident, Elf32_Ehdr, e_ident);
872	AssertCompileMembersSameSizeAndOffset(Elf64_Ehdr, e_type, Elf32_Ehdr, e_type);
873	AssertCompileMembersSameSizeAndOffset(Elf64_Ehdr, e_machine, Elf32_Ehdr, e_machine);
874	AssertCompileMembersSameSizeAndOffset(Elf64_Ehdr, e_version, Elf32_Ehdr, e_version);
875
876	rc = pVMM->pfnDBGFR3MemRead(pUVM, 0 /idCpu/, &HitAddr, &ElfHdr.ab[0], X86_PAGE_4K_SIZE);
877	if (RT_SUCCESS(rc))
878	{
879	/* We verified the magic above already by scanning for it. */
880	if ( ( ElfHdr.Hdr32.e_ident[EI_CLASS] == ELFCLASS32
881	\|\| ElfHdr.Hdr32.e_ident[EI_CLASS] == ELFCLASS64)
882	&& ElfHdr.Hdr32.e_ident[EI_DATA] == ELFDATA2LSB
883	&& ElfHdr.Hdr32.e_ident[EI_VERSION] == EV_CURRENT
884	&& ElfHdr.Hdr32.e_ident[EI_OSABI] == ELFOSABI_FREEBSD
885	&& ElfHdr.Hdr32.e_type == ET_EXEC
886	&& ( ElfHdr.Hdr32.e_machine == EM_386
887	\|\| ElfHdr.Hdr32.e_machine == EM_X86_64)
888	&& ElfHdr.Hdr32.e_version == EV_CURRENT)
889	{
890	pThis->f64Bit = ElfHdr.Hdr32.e_ident[EI_CLASS] == ELFCLASS64;
891	pThis->AddrKernelElfStart = HitAddr;
892	pThis->AddrKernelInterp = HitAddrInterp;
893	pVMM->pfnDBGFR3AddrFromFlat(pUVM, &pThis->AddrKernelText, FBSD_UNION(pThis, &ElfHdr, e_entry));
894	LogFunc(("Found %s FreeBSD kernel at %RGv (.interp section at %RGv, .text section at %RGv)\n",
895	pThis->f64Bit ? "amd64" : "i386", pThis->AddrKernelElfStart.FlatPtr,
896	pThis->AddrKernelInterp.FlatPtr, pThis->AddrKernelText.FlatPtr));
897	return true;
898	}
899	}
900	}
901
902	/*
903	* Advance.
904	*/
905	RTGCUINTPTR cbDistance = HitAddr.FlatPtr - KernelAddr.FlatPtr + sizeof(s_abNeedle) - 1;
906	if (RT_UNLIKELY(cbDistance >= cbLeft))
907	break;
908
909	cbLeft -= cbDistance;
910	pVMM->pfnDBGFR3AddrAdd(&KernelAddr, cbDistance);
911	}
912	}
913	return false;
914	}
915
916
917	/**
918	* @copydoc DBGFOSREG::pfnDestruct
919	*/
920	static DECLCALLBACK(void) dbgDiggerFreeBsdDestruct(PUVM pUVM, PCVMMR3VTABLE pVMM, void *pvData)
921	{
922	RT_NOREF(pUVM, pVMM, pvData);
923	}
924
925
926	/**
927	* @copydoc DBGFOSREG::pfnConstruct
928	*/
929	static DECLCALLBACK(int) dbgDiggerFreeBsdConstruct(PUVM pUVM, PCVMMR3VTABLE pVMM, void *pvData)
930	{
931	PDBGDIGGERFBSD pThis = (PDBGDIGGERFBSD)pvData;
932	RT_NOREF(pUVM, pVMM);
933
934	pThis->fValid = false;
935	pThis->f64Bit = false;
936	pThis->IDmesg.u32Magic = DBGFOSIDMESG_MAGIC;
937	pThis->IDmesg.pfnQueryKernelLog = dbgDiggerFreeBsdIDmsg_QueryKernelLog;
938	pThis->IDmesg.u32EndMagic = DBGFOSIDMESG_MAGIC;
939
940	return VINF_SUCCESS;
941	}
942
943
944	const DBGFOSREG g_DBGDiggerFreeBsd =
945	{
946	/* .u32Magic = */ DBGFOSREG_MAGIC,
947	/* .fFlags = */ 0,
948	/* .cbData = */ sizeof(DBGDIGGERFBSD),
949	/* .szName = */ "FreeBSD",
950	/* .pfnConstruct = */ dbgDiggerFreeBsdConstruct,
951	/* .pfnDestruct = */ dbgDiggerFreeBsdDestruct,
952	/* .pfnProbe = */ dbgDiggerFreeBsdProbe,
953	/* .pfnInit = */ dbgDiggerFreeBsdInit,
954	/* .pfnRefresh = */ dbgDiggerFreeBsdRefresh,
955	/* .pfnTerm = */ dbgDiggerFreeBsdTerm,
956	/* .pfnQueryVersion = */ dbgDiggerFreeBsdQueryVersion,
957	/* .pfnQueryInterface = */ dbgDiggerFreeBsdQueryInterface,
958	/* .pfnStackUnwindAssist = */ dbgDiggerFreeBsdStackUnwindAssist,
959	/* .u32EndMagic = */ DBGFOSREG_MAGIC
960	};
961

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source: vbox/trunk/src/VBox/Debugger/DBGPlugInFreeBsd.cpp@ 104255

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