1 | use alloc::fmt; |
2 | use alloc::vec::Vec; |
3 | use core::fmt::Debug; |
4 | use core::slice; |
5 | use core::str; |
6 | |
7 | use crate::endian::{self, Endianness}; |
8 | use crate::pod::Pod; |
9 | use crate::read::util::StringTable; |
10 | use crate::read::{ |
11 | self, ObjectSymbol, ObjectSymbolTable, ReadError, ReadRef, SectionIndex, SymbolFlags, |
12 | SymbolIndex, SymbolKind, SymbolMap, SymbolMapEntry, SymbolScope, SymbolSection, |
13 | }; |
14 | use crate::{elf, U32}; |
15 | |
16 | use super::{FileHeader, SectionHeader, SectionTable}; |
17 | |
18 | /// A table of symbol entries in an ELF file. |
19 | /// |
20 | /// Also includes the string table used for the symbol names. |
21 | /// |
22 | /// Returned by [`SectionTable::symbols`]. |
23 | #[derive (Debug, Clone, Copy)] |
24 | pub struct SymbolTable<'data, Elf: FileHeader, R = &'data [u8]> |
25 | where |
26 | R: ReadRef<'data>, |
27 | { |
28 | section: SectionIndex, |
29 | string_section: SectionIndex, |
30 | shndx_section: SectionIndex, |
31 | symbols: &'data [Elf::Sym], |
32 | strings: StringTable<'data, R>, |
33 | shndx: &'data [U32<Elf::Endian>], |
34 | } |
35 | |
36 | impl<'data, Elf: FileHeader, R: ReadRef<'data>> Default for SymbolTable<'data, Elf, R> { |
37 | fn default() -> Self { |
38 | SymbolTable { |
39 | section: SectionIndex(0), |
40 | string_section: SectionIndex(0), |
41 | shndx_section: SectionIndex(0), |
42 | symbols: &[], |
43 | strings: Default::default(), |
44 | shndx: &[], |
45 | } |
46 | } |
47 | } |
48 | |
49 | impl<'data, Elf: FileHeader, R: ReadRef<'data>> SymbolTable<'data, Elf, R> { |
50 | /// Parse the given symbol table section. |
51 | pub fn parse( |
52 | endian: Elf::Endian, |
53 | data: R, |
54 | sections: &SectionTable<'data, Elf, R>, |
55 | section_index: SectionIndex, |
56 | section: &Elf::SectionHeader, |
57 | ) -> read::Result<SymbolTable<'data, Elf, R>> { |
58 | debug_assert!( |
59 | section.sh_type(endian) == elf::SHT_DYNSYM |
60 | || section.sh_type(endian) == elf::SHT_SYMTAB |
61 | ); |
62 | |
63 | let symbols = section |
64 | .data_as_array(endian, data) |
65 | .read_error("Invalid ELF symbol table data" )?; |
66 | |
67 | let link = SectionIndex(section.sh_link(endian) as usize); |
68 | let strings = sections.strings(endian, data, link)?; |
69 | |
70 | let mut shndx_section = SectionIndex(0); |
71 | let mut shndx = &[][..]; |
72 | for (i, s) in sections.iter().enumerate() { |
73 | if s.sh_type(endian) == elf::SHT_SYMTAB_SHNDX |
74 | && s.sh_link(endian) as usize == section_index.0 |
75 | { |
76 | shndx_section = SectionIndex(i); |
77 | shndx = s |
78 | .data_as_array(endian, data) |
79 | .read_error("Invalid ELF symtab_shndx data" )?; |
80 | } |
81 | } |
82 | |
83 | Ok(SymbolTable { |
84 | section: section_index, |
85 | string_section: link, |
86 | symbols, |
87 | strings, |
88 | shndx, |
89 | shndx_section, |
90 | }) |
91 | } |
92 | |
93 | /// Return the section index of this symbol table. |
94 | #[inline ] |
95 | pub fn section(&self) -> SectionIndex { |
96 | self.section |
97 | } |
98 | |
99 | /// Return the section index of the shndx table. |
100 | #[inline ] |
101 | pub fn shndx_section(&self) -> SectionIndex { |
102 | self.shndx_section |
103 | } |
104 | |
105 | /// Return the section index of the linked string table. |
106 | #[inline ] |
107 | pub fn string_section(&self) -> SectionIndex { |
108 | self.string_section |
109 | } |
110 | |
111 | /// Return the string table used for the symbol names. |
112 | #[inline ] |
113 | pub fn strings(&self) -> StringTable<'data, R> { |
114 | self.strings |
115 | } |
116 | |
117 | /// Return the symbol table. |
118 | #[inline ] |
119 | pub fn symbols(&self) -> &'data [Elf::Sym] { |
120 | self.symbols |
121 | } |
122 | |
123 | /// Iterate over the symbols. |
124 | #[inline ] |
125 | pub fn iter(&self) -> slice::Iter<'data, Elf::Sym> { |
126 | self.symbols.iter() |
127 | } |
128 | |
129 | /// Return true if the symbol table is empty. |
130 | #[inline ] |
131 | pub fn is_empty(&self) -> bool { |
132 | self.symbols.is_empty() |
133 | } |
134 | |
135 | /// The number of symbols. |
136 | #[inline ] |
137 | pub fn len(&self) -> usize { |
138 | self.symbols.len() |
139 | } |
140 | |
141 | /// Return the symbol at the given index. |
142 | pub fn symbol(&self, index: usize) -> read::Result<&'data Elf::Sym> { |
143 | self.symbols |
144 | .get(index) |
145 | .read_error("Invalid ELF symbol index" ) |
146 | } |
147 | |
148 | /// Return the extended section index for the given symbol if present. |
149 | #[inline ] |
150 | pub fn shndx(&self, endian: Elf::Endian, index: usize) -> Option<u32> { |
151 | self.shndx.get(index).map(|x| x.get(endian)) |
152 | } |
153 | |
154 | /// Return the section index for the given symbol. |
155 | /// |
156 | /// This uses the extended section index if present. |
157 | pub fn symbol_section( |
158 | &self, |
159 | endian: Elf::Endian, |
160 | symbol: &'data Elf::Sym, |
161 | index: usize, |
162 | ) -> read::Result<Option<SectionIndex>> { |
163 | match symbol.st_shndx(endian) { |
164 | elf::SHN_UNDEF => Ok(None), |
165 | elf::SHN_XINDEX => self |
166 | .shndx(endian, index) |
167 | .read_error("Missing ELF symbol extended index" ) |
168 | .map(|index| Some(SectionIndex(index as usize))), |
169 | shndx if shndx < elf::SHN_LORESERVE => Ok(Some(SectionIndex(shndx.into()))), |
170 | _ => Ok(None), |
171 | } |
172 | } |
173 | |
174 | /// Return the symbol name for the given symbol. |
175 | pub fn symbol_name( |
176 | &self, |
177 | endian: Elf::Endian, |
178 | symbol: &'data Elf::Sym, |
179 | ) -> read::Result<&'data [u8]> { |
180 | symbol.name(endian, self.strings) |
181 | } |
182 | |
183 | /// Construct a map from addresses to a user-defined map entry. |
184 | pub fn map<Entry: SymbolMapEntry, F: Fn(&'data Elf::Sym) -> Option<Entry>>( |
185 | &self, |
186 | endian: Elf::Endian, |
187 | f: F, |
188 | ) -> SymbolMap<Entry> { |
189 | let mut symbols = Vec::with_capacity(self.symbols.len()); |
190 | for symbol in self.symbols { |
191 | if !symbol.is_definition(endian) { |
192 | continue; |
193 | } |
194 | if let Some(entry) = f(symbol) { |
195 | symbols.push(entry); |
196 | } |
197 | } |
198 | SymbolMap::new(symbols) |
199 | } |
200 | } |
201 | |
202 | /// A symbol table in an [`ElfFile32`](super::ElfFile32). |
203 | pub type ElfSymbolTable32<'data, 'file, Endian = Endianness, R = &'data [u8]> = |
204 | ElfSymbolTable<'data, 'file, elf::FileHeader32<Endian>, R>; |
205 | /// A symbol table in an [`ElfFile32`](super::ElfFile32). |
206 | pub type ElfSymbolTable64<'data, 'file, Endian = Endianness, R = &'data [u8]> = |
207 | ElfSymbolTable<'data, 'file, elf::FileHeader64<Endian>, R>; |
208 | |
209 | /// A symbol table in an [`ElfFile`](super::ElfFile). |
210 | #[derive (Debug, Clone, Copy)] |
211 | pub struct ElfSymbolTable<'data, 'file, Elf, R = &'data [u8]> |
212 | where |
213 | Elf: FileHeader, |
214 | R: ReadRef<'data>, |
215 | { |
216 | pub(super) endian: Elf::Endian, |
217 | pub(super) symbols: &'file SymbolTable<'data, Elf, R>, |
218 | } |
219 | |
220 | impl<'data, 'file, Elf: FileHeader, R: ReadRef<'data>> read::private::Sealed |
221 | for ElfSymbolTable<'data, 'file, Elf, R> |
222 | { |
223 | } |
224 | |
225 | impl<'data, 'file, Elf: FileHeader, R: ReadRef<'data>> ObjectSymbolTable<'data> |
226 | for ElfSymbolTable<'data, 'file, Elf, R> |
227 | { |
228 | type Symbol = ElfSymbol<'data, 'file, Elf, R>; |
229 | type SymbolIterator = ElfSymbolIterator<'data, 'file, Elf, R>; |
230 | |
231 | fn symbols(&self) -> Self::SymbolIterator { |
232 | ElfSymbolIterator { |
233 | endian: self.endian, |
234 | symbols: self.symbols, |
235 | index: 0, |
236 | } |
237 | } |
238 | |
239 | fn symbol_by_index(&self, index: SymbolIndex) -> read::Result<Self::Symbol> { |
240 | let symbol: &::Sym = self.symbols.symbol(index:index.0)?; |
241 | Ok(ElfSymbol { |
242 | endian: self.endian, |
243 | symbols: self.symbols, |
244 | index, |
245 | symbol, |
246 | }) |
247 | } |
248 | } |
249 | |
250 | /// An iterator for the symbols in an [`ElfFile32`](super::ElfFile32). |
251 | pub type ElfSymbolIterator32<'data, 'file, Endian = Endianness, R = &'data [u8]> = |
252 | ElfSymbolIterator<'data, 'file, elf::FileHeader32<Endian>, R>; |
253 | /// An iterator for the symbols in an [`ElfFile64`](super::ElfFile64). |
254 | pub type ElfSymbolIterator64<'data, 'file, Endian = Endianness, R = &'data [u8]> = |
255 | ElfSymbolIterator<'data, 'file, elf::FileHeader64<Endian>, R>; |
256 | |
257 | /// An iterator for the symbols in an [`ElfFile`](super::ElfFile). |
258 | pub struct ElfSymbolIterator<'data, 'file, Elf, R = &'data [u8]> |
259 | where |
260 | Elf: FileHeader, |
261 | R: ReadRef<'data>, |
262 | { |
263 | pub(super) endian: Elf::Endian, |
264 | pub(super) symbols: &'file SymbolTable<'data, Elf, R>, |
265 | pub(super) index: usize, |
266 | } |
267 | |
268 | impl<'data, 'file, Elf: FileHeader, R: ReadRef<'data>> fmt::Debug |
269 | for ElfSymbolIterator<'data, 'file, Elf, R> |
270 | { |
271 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
272 | f.debug_struct(name:"ElfSymbolIterator" ).finish() |
273 | } |
274 | } |
275 | |
276 | impl<'data, 'file, Elf: FileHeader, R: ReadRef<'data>> Iterator |
277 | for ElfSymbolIterator<'data, 'file, Elf, R> |
278 | { |
279 | type Item = ElfSymbol<'data, 'file, Elf, R>; |
280 | |
281 | fn next(&mut self) -> Option<Self::Item> { |
282 | let index: usize = self.index; |
283 | let symbol: &::Sym = self.symbols.symbols.get(index)?; |
284 | self.index += 1; |
285 | Some(ElfSymbol { |
286 | endian: self.endian, |
287 | symbols: self.symbols, |
288 | index: SymbolIndex(index), |
289 | symbol, |
290 | }) |
291 | } |
292 | } |
293 | |
294 | /// A symbol in an [`ElfFile32`](super::ElfFile32). |
295 | pub type ElfSymbol32<'data, 'file, Endian = Endianness, R = &'data [u8]> = |
296 | ElfSymbol<'data, 'file, elf::FileHeader32<Endian>, R>; |
297 | /// A symbol in an [`ElfFile64`](super::ElfFile64). |
298 | pub type ElfSymbol64<'data, 'file, Endian = Endianness, R = &'data [u8]> = |
299 | ElfSymbol<'data, 'file, elf::FileHeader64<Endian>, R>; |
300 | |
301 | /// A symbol in an [`ElfFile`](super::ElfFile). |
302 | /// |
303 | /// Most functionality is provided by the [`ObjectSymbol`] trait implementation. |
304 | #[derive (Debug, Clone, Copy)] |
305 | pub struct ElfSymbol<'data, 'file, Elf, R = &'data [u8]> |
306 | where |
307 | Elf: FileHeader, |
308 | R: ReadRef<'data>, |
309 | { |
310 | pub(super) endian: Elf::Endian, |
311 | pub(super) symbols: &'file SymbolTable<'data, Elf, R>, |
312 | pub(super) index: SymbolIndex, |
313 | pub(super) symbol: &'data Elf::Sym, |
314 | } |
315 | |
316 | impl<'data, 'file, Elf: FileHeader, R: ReadRef<'data>> ElfSymbol<'data, 'file, Elf, R> { |
317 | /// Return a reference to the raw symbol structure. |
318 | #[inline ] |
319 | pub fn raw_symbol(&self) -> &'data Elf::Sym { |
320 | self.symbol |
321 | } |
322 | } |
323 | |
324 | impl<'data, 'file, Elf: FileHeader, R: ReadRef<'data>> read::private::Sealed |
325 | for ElfSymbol<'data, 'file, Elf, R> |
326 | { |
327 | } |
328 | |
329 | impl<'data, 'file, Elf: FileHeader, R: ReadRef<'data>> ObjectSymbol<'data> |
330 | for ElfSymbol<'data, 'file, Elf, R> |
331 | { |
332 | #[inline ] |
333 | fn index(&self) -> SymbolIndex { |
334 | self.index |
335 | } |
336 | |
337 | fn name_bytes(&self) -> read::Result<&'data [u8]> { |
338 | self.symbol.name(self.endian, self.symbols.strings()) |
339 | } |
340 | |
341 | fn name(&self) -> read::Result<&'data str> { |
342 | let name = self.name_bytes()?; |
343 | str::from_utf8(name) |
344 | .ok() |
345 | .read_error("Non UTF-8 ELF symbol name" ) |
346 | } |
347 | |
348 | #[inline ] |
349 | fn address(&self) -> u64 { |
350 | self.symbol.st_value(self.endian).into() |
351 | } |
352 | |
353 | #[inline ] |
354 | fn size(&self) -> u64 { |
355 | self.symbol.st_size(self.endian).into() |
356 | } |
357 | |
358 | fn kind(&self) -> SymbolKind { |
359 | match self.symbol.st_type() { |
360 | elf::STT_NOTYPE if self.index.0 == 0 => SymbolKind::Null, |
361 | elf::STT_NOTYPE => SymbolKind::Unknown, |
362 | elf::STT_OBJECT | elf::STT_COMMON => SymbolKind::Data, |
363 | elf::STT_FUNC | elf::STT_GNU_IFUNC => SymbolKind::Text, |
364 | elf::STT_SECTION => SymbolKind::Section, |
365 | elf::STT_FILE => SymbolKind::File, |
366 | elf::STT_TLS => SymbolKind::Tls, |
367 | _ => SymbolKind::Unknown, |
368 | } |
369 | } |
370 | |
371 | fn section(&self) -> SymbolSection { |
372 | match self.symbol.st_shndx(self.endian) { |
373 | elf::SHN_UNDEF => SymbolSection::Undefined, |
374 | elf::SHN_ABS => { |
375 | if self.symbol.st_type() == elf::STT_FILE { |
376 | SymbolSection::None |
377 | } else { |
378 | SymbolSection::Absolute |
379 | } |
380 | } |
381 | elf::SHN_COMMON => SymbolSection::Common, |
382 | elf::SHN_XINDEX => match self.symbols.shndx(self.endian, self.index.0) { |
383 | Some(index) => SymbolSection::Section(SectionIndex(index as usize)), |
384 | None => SymbolSection::Unknown, |
385 | }, |
386 | index if index < elf::SHN_LORESERVE => { |
387 | SymbolSection::Section(SectionIndex(index as usize)) |
388 | } |
389 | _ => SymbolSection::Unknown, |
390 | } |
391 | } |
392 | |
393 | #[inline ] |
394 | fn is_undefined(&self) -> bool { |
395 | self.symbol.st_shndx(self.endian) == elf::SHN_UNDEF |
396 | } |
397 | |
398 | #[inline ] |
399 | fn is_definition(&self) -> bool { |
400 | self.symbol.is_definition(self.endian) |
401 | } |
402 | |
403 | #[inline ] |
404 | fn is_common(&self) -> bool { |
405 | self.symbol.st_shndx(self.endian) == elf::SHN_COMMON |
406 | } |
407 | |
408 | #[inline ] |
409 | fn is_weak(&self) -> bool { |
410 | self.symbol.st_bind() == elf::STB_WEAK |
411 | } |
412 | |
413 | fn scope(&self) -> SymbolScope { |
414 | if self.symbol.st_shndx(self.endian) == elf::SHN_UNDEF { |
415 | SymbolScope::Unknown |
416 | } else { |
417 | match self.symbol.st_bind() { |
418 | elf::STB_LOCAL => SymbolScope::Compilation, |
419 | elf::STB_GLOBAL | elf::STB_WEAK => { |
420 | if self.symbol.st_visibility() == elf::STV_HIDDEN { |
421 | SymbolScope::Linkage |
422 | } else { |
423 | SymbolScope::Dynamic |
424 | } |
425 | } |
426 | _ => SymbolScope::Unknown, |
427 | } |
428 | } |
429 | } |
430 | |
431 | #[inline ] |
432 | fn is_global(&self) -> bool { |
433 | self.symbol.st_bind() != elf::STB_LOCAL |
434 | } |
435 | |
436 | #[inline ] |
437 | fn is_local(&self) -> bool { |
438 | self.symbol.st_bind() == elf::STB_LOCAL |
439 | } |
440 | |
441 | #[inline ] |
442 | fn flags(&self) -> SymbolFlags<SectionIndex, SymbolIndex> { |
443 | SymbolFlags::Elf { |
444 | st_info: self.symbol.st_info(), |
445 | st_other: self.symbol.st_other(), |
446 | } |
447 | } |
448 | } |
449 | |
450 | /// A trait for generic access to [`elf::Sym32`] and [`elf::Sym64`]. |
451 | #[allow (missing_docs)] |
452 | pub trait Sym: Debug + Pod { |
453 | type Word: Into<u64>; |
454 | type Endian: endian::Endian; |
455 | |
456 | fn st_name(&self, endian: Self::Endian) -> u32; |
457 | fn st_info(&self) -> u8; |
458 | fn st_bind(&self) -> u8; |
459 | fn st_type(&self) -> u8; |
460 | fn st_other(&self) -> u8; |
461 | fn st_visibility(&self) -> u8; |
462 | fn st_shndx(&self, endian: Self::Endian) -> u16; |
463 | fn st_value(&self, endian: Self::Endian) -> Self::Word; |
464 | fn st_size(&self, endian: Self::Endian) -> Self::Word; |
465 | |
466 | /// Parse the symbol name from the string table. |
467 | fn name<'data, R: ReadRef<'data>>( |
468 | &self, |
469 | endian: Self::Endian, |
470 | strings: StringTable<'data, R>, |
471 | ) -> read::Result<&'data [u8]> { |
472 | strings |
473 | .get(self.st_name(endian)) |
474 | .read_error("Invalid ELF symbol name offset" ) |
475 | } |
476 | |
477 | /// Return true if the symbol is undefined. |
478 | #[inline ] |
479 | fn is_undefined(&self, endian: Self::Endian) -> bool { |
480 | self.st_shndx(endian) == elf::SHN_UNDEF |
481 | } |
482 | |
483 | /// Return true if the symbol is a definition of a function or data object. |
484 | fn is_definition(&self, endian: Self::Endian) -> bool { |
485 | let shndx = self.st_shndx(endian); |
486 | if shndx == elf::SHN_UNDEF || (shndx >= elf::SHN_LORESERVE && shndx != elf::SHN_XINDEX) { |
487 | return false; |
488 | } |
489 | match self.st_type() { |
490 | elf::STT_NOTYPE => self.st_size(endian).into() != 0, |
491 | elf::STT_FUNC | elf::STT_OBJECT => true, |
492 | _ => false, |
493 | } |
494 | } |
495 | } |
496 | |
497 | impl<Endian: endian::Endian> Sym for elf::Sym32<Endian> { |
498 | type Word = u32; |
499 | type Endian = Endian; |
500 | |
501 | #[inline ] |
502 | fn st_name(&self, endian: Self::Endian) -> u32 { |
503 | self.st_name.get(endian) |
504 | } |
505 | |
506 | #[inline ] |
507 | fn st_info(&self) -> u8 { |
508 | self.st_info |
509 | } |
510 | |
511 | #[inline ] |
512 | fn st_bind(&self) -> u8 { |
513 | self.st_bind() |
514 | } |
515 | |
516 | #[inline ] |
517 | fn st_type(&self) -> u8 { |
518 | self.st_type() |
519 | } |
520 | |
521 | #[inline ] |
522 | fn st_other(&self) -> u8 { |
523 | self.st_other |
524 | } |
525 | |
526 | #[inline ] |
527 | fn st_visibility(&self) -> u8 { |
528 | self.st_visibility() |
529 | } |
530 | |
531 | #[inline ] |
532 | fn st_shndx(&self, endian: Self::Endian) -> u16 { |
533 | self.st_shndx.get(endian) |
534 | } |
535 | |
536 | #[inline ] |
537 | fn st_value(&self, endian: Self::Endian) -> Self::Word { |
538 | self.st_value.get(endian) |
539 | } |
540 | |
541 | #[inline ] |
542 | fn st_size(&self, endian: Self::Endian) -> Self::Word { |
543 | self.st_size.get(endian) |
544 | } |
545 | } |
546 | |
547 | impl<Endian: endian::Endian> Sym for elf::Sym64<Endian> { |
548 | type Word = u64; |
549 | type Endian = Endian; |
550 | |
551 | #[inline ] |
552 | fn st_name(&self, endian: Self::Endian) -> u32 { |
553 | self.st_name.get(endian) |
554 | } |
555 | |
556 | #[inline ] |
557 | fn st_info(&self) -> u8 { |
558 | self.st_info |
559 | } |
560 | |
561 | #[inline ] |
562 | fn st_bind(&self) -> u8 { |
563 | self.st_bind() |
564 | } |
565 | |
566 | #[inline ] |
567 | fn st_type(&self) -> u8 { |
568 | self.st_type() |
569 | } |
570 | |
571 | #[inline ] |
572 | fn st_other(&self) -> u8 { |
573 | self.st_other |
574 | } |
575 | |
576 | #[inline ] |
577 | fn st_visibility(&self) -> u8 { |
578 | self.st_visibility() |
579 | } |
580 | |
581 | #[inline ] |
582 | fn st_shndx(&self, endian: Self::Endian) -> u16 { |
583 | self.st_shndx.get(endian) |
584 | } |
585 | |
586 | #[inline ] |
587 | fn st_value(&self, endian: Self::Endian) -> Self::Word { |
588 | self.st_value.get(endian) |
589 | } |
590 | |
591 | #[inline ] |
592 | fn st_size(&self, endian: Self::Endian) -> Self::Word { |
593 | self.st_size.get(endian) |
594 | } |
595 | } |
596 | |