DBGPlugInCommonELFTmpl.cpp.h@ 97405

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1	/* $Id: DBGPlugInCommonELFTmpl.cpp.h 96407 2022-08-22 17:43:14Z vboxsync $ */
2	/** @file
3	* DBGPlugInCommonELF - Code Template for dealing with one kind of ELF.
4	*/
5
6	/*
7	* Copyright (C) 2008-2022 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	#if ELF_MODE == 32
29	# define Elf_Ehdr Elf32_Ehdr
30	# define Elf_Shdr Elf32_Shdr
31	# define Elf_Phdr Elf32_Phdr
32	# define Elf_Sym Elf32_Sym
33	# define MY_ELFCLASS ELFCLASS32
34	# define ELF_ST_BIND ELF32_ST_BIND
35	# define DBGDiggerCommonParseElfMod DBGDiggerCommonParseElf32Mod
36	#else
37	# define Elf_Ehdr Elf64_Ehdr
38	# define Elf_Shdr Elf64_Shdr
39	# define Elf_Phdr Elf64_Phdr
40	# define Elf_Sym Elf64_Sym
41	# define MY_ELFCLASS ELFCLASS64
42	# define ELF_ST_BIND ELF64_ST_BIND
43	# define DBGDiggerCommonParseElfMod DBGDiggerCommonParseElf64Mod
44	#endif
45
46
47	/**
48	* Common ELF module parser.
49	*
50	* It takes the essential bits of the ELF module (elf header, section headers,
51	* symbol table and string table), and inserts/updates the module and symbols.
52	*
53	*
54	* @returns VBox status code.
55	*
56	* @param pUVM The user mode VM handle.
57	* @param pVMM The VMM function table.
58	* @param pszModName The module name.
59	* @param pszFilename The filename. optional.
60	* @param fFlags Flags.
61	* @param pEhdr Pointer to the ELF header.
62	* @param paShdrs Pointer to the section headers. The caller must verify that
63	* the e_shnum member of the ELF header is within the bounds of
64	* this table. The caller should also adjust the section addresses
65	* so these correspond to actual load addresses.
66	* @param paSyms Pointer to the symbol table.
67	* @param cMaxSyms The maximum number of symbols paSyms may hold. This isn't
68	* the exact count, it's just a cap for avoiding SIGSEGVs
69	* and general corruption.
70	* @param pbStrings Pointer to the string table.
71	* @param cbMaxStrings The size of the memory pbStrings points to. This doesn't
72	* have to match the string table size exactly, it's just to
73	* avoid SIGSEGV when a bad string index is encountered.
74	* @param MinAddr Min address to care about.
75	* @param MaxAddr Max address to care about (inclusive). Together
76	* with MinAddr this forms a valid address range for
77	* symbols and sections that we care about. Anything
78	* outside the range is ignored, except when doing
79	* sanity checks..
80	* @param uModTag Module tag. Pass 0 if tagging is of no interest.
81	*/
82	int DBGDiggerCommonParseElfMod(PUVM pUVM, PCVMMR3VTABLE pVMM, const char pszModName, const char pszFilename, uint32_t fFlags,
83	Elf_Ehdr const pEhdr, Elf_Shdr const paShdrs,
84	Elf_Sym const *paSyms, size_t cMaxSyms,
85	char const *pbStrings, size_t cbMaxStrings,
86	RTGCPTR MinAddr, RTGCPTR MaxAddr, uint64_t uModTag)
87	{
88	AssertPtrReturn(pUVM, VERR_INVALID_POINTER);
89	AssertPtrReturn(pVMM, VERR_INVALID_POINTER);
90	AssertPtrReturn(pszModName, VERR_INVALID_POINTER);
91	AssertPtrReturn(pszFilename, VERR_INVALID_POINTER);
92	AssertReturn(!(fFlags & ~DBG_DIGGER_ELF_MASK), VERR_INVALID_PARAMETER);
93	AssertReturn((fFlags & (DBG_DIGGER_ELF_FUNNY_SHDRS \| DBG_DIGGER_ELF_ADJUST_SYM_VALUE))
94	!= (DBG_DIGGER_ELF_FUNNY_SHDRS \| DBG_DIGGER_ELF_ADJUST_SYM_VALUE), VERR_INVALID_PARAMETER);
95	AssertPtrReturn(paShdrs, VERR_INVALID_POINTER);
96	AssertPtrReturn(paSyms, VERR_INVALID_POINTER);
97	AssertPtrReturn(pbStrings, VERR_INVALID_POINTER);
98
99	/*
100	* Validate the ELF header.
101	*/
102	if ( pEhdr->e_ident[EI_MAG0] != ELFMAG0
103	\|\| pEhdr->e_ident[EI_MAG1] != ELFMAG1
104	\|\| pEhdr->e_ident[EI_MAG2] != ELFMAG2
105	\|\| pEhdr->e_ident[EI_MAG3] != ELFMAG3)
106	return VERR_INVALID_EXE_SIGNATURE;
107	if (pEhdr->e_ident[EI_CLASS] != MY_ELFCLASS)
108	return VERR_LDRELF_MACHINE;
109
110	if (pEhdr->e_ident[EI_DATA] != ELFDATA2LSB)
111	return VERR_LDRELF_ODD_ENDIAN;
112	if (pEhdr->e_ident[EI_VERSION] != EV_CURRENT)
113	return VERR_LDRELF_VERSION;
114	if (pEhdr->e_version != EV_CURRENT)
115	return VERR_LDRELF_VERSION;
116	if (pEhdr->e_ehsize != sizeof(*pEhdr))
117	return VERR_BAD_EXE_FORMAT;
118
119	#if ELF_MODE == 32
120	if ( pEhdr->e_machine != EM_386
121	&& pEhdr->e_machine != EM_486)
122	return VERR_LDRELF_MACHINE;
123	#else
124	if (pEhdr->e_machine != EM_X86_64)
125	return VERR_LDRELF_MACHINE;
126	#endif
127
128	if ( pEhdr->e_type != ET_DYN
129	&& pEhdr->e_type != ET_REL
130	&& pEhdr->e_type != ET_EXEC) //??
131	return VERR_BAD_EXE_FORMAT;
132	if ( pEhdr->e_phentsize != sizeof(Elf_Phdr)
133	&& pEhdr->e_phentsize) //??
134	return VERR_BAD_EXE_FORMAT;
135	if (pEhdr->e_shentsize != sizeof(Elf_Shdr))
136	return VERR_BAD_EXE_FORMAT;
137	if (pEhdr->e_shentsize != sizeof(Elf_Shdr))
138	return VERR_BAD_EXE_FORMAT;
139	if (!ASMMemIsZero(&pEhdr->e_ident[EI_PAD], EI_NIDENT - EI_PAD)) //??
140	return VERR_BAD_EXE_FORMAT;
141
142	/*
143	* Validate the section headers, finding the string and symbol table
144	* headers and the load address while at it.
145	*/
146	uint64_t uLoadAddr = UINT64_MAX;
147	const Elf_Shdr *pSymShdr = NULL;
148	const Elf_Shdr *pStrShdr = NULL;
149	for (unsigned iSh = fFlags & DBG_DIGGER_ELF_FUNNY_SHDRS ? 1 : 0; iSh < pEhdr->e_shnum; iSh++)
150	{
151	/* Minimal validation. */
152	if (paShdrs[iSh].sh_link >= pEhdr->e_shnum)
153	return VERR_BAD_EXE_FORMAT;
154
155	/* Is it the symbol table?*/
156	if (paShdrs[iSh].sh_type == SHT_SYMTAB)
157	{
158	if (pSymShdr)
159	return VERR_LDRELF_MULTIPLE_SYMTABS;
160	pSymShdr = &paShdrs[iSh];
161	if (pSymShdr->sh_entsize != sizeof(Elf32_Sym))
162	return VERR_BAD_EXE_FORMAT;
163	pStrShdr = &paShdrs[paShdrs[iSh].sh_link];
164	}
165	if (uLoadAddr > paShdrs[iSh].sh_addr)
166	uLoadAddr = paShdrs[iSh].sh_addr;
167	}
168
169	/*
170	* Validate the symbol table and determine the max section index
171	* when DBG_DIGGER_ELF_FUNNY_SHDRS is flagged.
172	*/
173	uint32_t uMaxShIdx = fFlags & DBG_DIGGER_ELF_FUNNY_SHDRS ? 0 : pEhdr->e_shnum - 1;
174	size_t const cbStrings = pStrShdr ? pStrShdr->sh_size : cbMaxStrings;
175	size_t const cSyms = pSymShdr
176	? RT_MIN(cMaxSyms, pSymShdr->sh_size / sizeof(Elf_Sym))
177	: cMaxSyms;
178	for (size_t iSym = 1; iSym < cSyms; iSym++)
179	{
180	if (paSyms[iSym].st_name >= cbStrings)
181	return VERR_LDRELF_INVALID_SYMBOL_NAME_OFFSET;
182	if (fFlags & DBG_DIGGER_ELF_FUNNY_SHDRS)
183	{
184	if ( paSyms[iSym].st_shndx > uMaxShIdx
185	&& paSyms[iSym].st_shndx < SHN_LORESERVE)
186	uMaxShIdx = paSyms[iSym].st_shndx;
187	}
188	else if ( paSyms[iSym].st_shndx >= pEhdr->e_shnum
189	&& paSyms[iSym].st_shndx != SHN_UNDEF
190	&& ( paSyms[iSym].st_shndx < SHN_LORESERVE
191	/\|\| paSyms[iSym].st_shndx > SHN_HIRESERVE/
192	\|\| ELF_ST_BIND(paSyms[iSym].st_info) == STB_GLOBAL
193	\|\| ELF_ST_BIND(paSyms[iSym].st_info) == STB_WEAK) )
194	return VERR_BAD_EXE_FORMAT;
195	}
196	if (uMaxShIdx > 4096)
197	return VERR_BAD_EXE_FORMAT;
198
199	/*
200	* Create new module.
201	* The funny ELF section headers on solaris makes this very complicated.
202	*/
203	uint32_t cSegs = uMaxShIdx + 1;
204	PDBGDIGGERELFSEG paSegs = (PDBGDIGGERELFSEG)alloca(sizeof(paSegs[0]) * cSegs);
205	for (uint32_t i = 0; i < cSegs; i++)
206	{
207	paSegs[i].uLoadAddr = RTGCPTR_MAX;
208	paSegs[i].uLastAddr = 0;
209	paSegs[i].iSeg = NIL_RTDBGSEGIDX;
210	}
211
212	RTDBGMOD hMod;
213	int rc = RTDbgModCreate(&hMod, pszModName, 0 /cbSeg/, 0 /fFlags/);
214	if (RT_FAILURE(rc))
215	return rc;
216	rc = RTDbgModSetTag(hMod, uModTag); AssertRC(rc);
217
218	if (fFlags & DBG_DIGGER_ELF_FUNNY_SHDRS)
219	{
220	/* Seek out the min and max symbol values for each section. */
221	for (uint32_t iSym = 1; iSym < cSyms; iSym++)
222	{
223	/* Ignore undefined, absolute and weak symbols in this pass,
224	but include local ones as well as nameless. */
225	uint32_t iSh = paSyms[iSym].st_shndx;
226	if ( iSh != SHN_UNDEF
227	&& iSh < cSegs
228	&& ( ELF_ST_BIND(paSyms[iSym].st_info) == STB_GLOBAL
229	\|\| ELF_ST_BIND(paSyms[iSym].st_info) == STB_LOCAL))
230	{
231	/* Calc the address and check that it doesn't wrap with the size. */
232	RTGCUINTPTR Address = paSyms[iSym].st_value;
233	RTGCUINTPTR AddressLast = Address + RT_MAX(paSyms[iSym].st_size, 1) - 1;
234	if (AddressLast < Address)
235	continue;
236	if ( Address < MinAddr
237	\|\| AddressLast > MaxAddr)
238	continue;
239
240	/* update min/max. */
241	if (Address < paSegs[iSh].uLoadAddr)
242	paSegs[iSh].uLoadAddr = Address;
243	if (AddressLast > paSegs[iSh].uLastAddr)
244	paSegs[iSh].uLastAddr = AddressLast;
245	}
246	}
247
248	/* Add the segments and fill in the translation table. */
249	RTGCPTR uRvaNext = 0;
250	for (unsigned i = 0; i < cSegs; i++)
251	if (paSegs[i].uLastAddr != 0)
252	{
253	char szSeg[32];
254	RTStrPrintf(szSeg, sizeof(szSeg), "sec%02u", i);
255	RTGCPTR cbSeg = paSegs[i].uLastAddr - paSegs[i].uLoadAddr + 1;
256	rc = RTDbgModSegmentAdd(hMod, uRvaNext, cbSeg, szSeg, 0 /fFlags/, &paSegs[i].iSeg);
257	if (RT_FAILURE(rc))
258	break;
259	uRvaNext += RT_ALIGN_T(cbSeg, 32, RTGCPTR);
260	}
261	}
262	else
263	{
264	/* Add the segments and fill in the translation table. */
265	for (unsigned i = 0; i < cSegs; i++)
266	if (paShdrs[i].sh_flags & SHF_ALLOC)
267	{
268	char szSeg[32];
269	RTStrPrintf(szSeg, sizeof(szSeg), "sec%02u", i);
270	rc = RTDbgModSegmentAdd(hMod, paShdrs[i].sh_addr - uLoadAddr, paShdrs[i].sh_size, szSeg, 0 /fFlags/, &paSegs[i].iSeg);
271	if (RT_FAILURE(rc))
272	break;
273	paSegs[i].uLoadAddr = paShdrs[i].sh_addr;
274	paSegs[i].uLastAddr = paShdrs[i].sh_addr + paShdrs[i].sh_size - 1;
275	}
276	}
277	if (RT_FAILURE(rc))
278	{
279	RTDbgModRelease(hMod);
280	return rc;
281	}
282
283
284	/*
285	* Add all relevant symbols in the module
286	*/
287	for (uint32_t iSym = 1; iSym < cSyms; iSym++)
288	{
289	/* Undefined symbols are not exports, they are imports. */
290	RTDBGSEGIDX iSeg = paSyms[iSym].st_shndx;
291	if ( iSeg != SHN_UNDEF
292	&& ( ELF_ST_BIND(paSyms[iSym].st_info) == STB_GLOBAL
293	\|\| ELF_ST_BIND(paSyms[iSym].st_info) == STB_LOCAL
294	\|\| ELF_ST_BIND(paSyms[iSym].st_info) == STB_WEAK))
295	{
296	/* Get the symbol name. */
297	if (paSyms[iSym].st_name >= cbMaxStrings)
298	continue;
299	const char *pszSymbol = pbStrings + paSyms[iSym].st_name;
300	if (!*pszSymbol)
301	continue;
302
303	/* Calc the address (value) and size. */
304	RTGCUINTPTR cbSym = paSyms[iSym].st_size;
305	RTGCUINTPTR offSeg = paSyms[iSym].st_value;
306	if (iSeg == SHN_ABS)
307	iSeg = RTDBGSEGIDX_ABS; /* absolute symbols are not subject to any relocation. */
308	else
309	{
310	Assert(iSeg < cSegs);
311	if (fFlags & (DBG_DIGGER_ELF_FUNNY_SHDRS \| DBG_DIGGER_ELF_ADJUST_SYM_VALUE))
312	offSeg -= paSegs[iSeg].uLoadAddr;
313	iSeg = paSegs[iSeg].iSeg;
314	if (iSeg == NIL_RTDBGSEGIDX)
315	continue;
316	}
317	if (offSeg + cbSym < offSeg)
318	continue;
319
320	rc = RTDbgModSymbolAdd(hMod, pszSymbol, iSeg, offSeg, cbSym, 0 /fFlags/, NULL);
321	Log(("%02x:%RGv %RGv %s!%s (rc=%Rrc)\n", paSyms[iSym].st_shndx, offSeg, cbSym, pszModName, pszSymbol, rc));
322	}
323	/else: silently ignore /
324	}
325
326	/*
327	* Link it into the address space.
328	*/
329	RTDBGAS hAs = pVMM->pfnDBGFR3AsResolveAndRetain(pUVM, DBGF_AS_KERNEL);
330	if (hAs != NIL_RTDBGAS)
331	rc = dbgDiggerCommonLinkElfSegs(hAs, hMod, paSegs, cSegs);
332	else
333	rc = VERR_INTERNAL_ERROR;
334	RTDbgModRelease(hMod);
335	RTDbgAsRelease(hAs);
336	return rc;
337	}
338
339
340	#undef Elf_Ehdr
341	#undef Elf_Shdr
342	#undef Elf_Phdr
343	#undef Elf_Sym
344	#undef MY_ELFCLASS
345	#undef ELF_ST_BIND
346	#undef DBGDiggerCommonParseElfMod
347

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source: vbox/trunk/src/VBox/Debugger/DBGPlugInCommonELFTmpl.cpp.h@ 97405

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