Load ELF symbol information from GTIRB and compare to readelf #477
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| Original file line number | Diff line number | Diff line change |
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| package gtirb | ||
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| import util.Logger | ||
| import gtirb.AuxDecoder | ||
| import gtirb.AuxDecoder.{AuxKind, decodeAux} | ||
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| import translating.{ELFSymType, ELFBind, ELFVis, ELFNDX, ELFSymbol, ReadELFData} | ||
| import specification.{ExternalFunction, FuncEntry} | ||
| import boogie.{SpecGlobal} | ||
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| import java.io.ByteArrayInputStream | ||
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| import com.google.protobuf.ByteString | ||
| import com.grammatech.gtirb.proto.CFG.EdgeType.* | ||
| import com.grammatech.gtirb.proto.CFG.CFG | ||
| import com.grammatech.gtirb.proto.CFG.Edge | ||
| import com.grammatech.gtirb.proto.CFG.EdgeLabel | ||
| import com.grammatech.gtirb.proto.Module.Module | ||
| import com.grammatech.gtirb.proto.Symbol.Symbol | ||
| import com.grammatech.gtirb.proto.ByteInterval.Block | ||
| import com.grammatech.gtirb.proto.ByteInterval.ByteInterval | ||
| import com.grammatech.gtirb.proto.Symbol.Symbol.OptionalPayload | ||
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| import scala.collection.mutable | ||
| import scala.collection.immutable.{SortedMap, SortedSet} | ||
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| class GTIRBReadELF(protected val gtirb: GTIRBResolver) { | ||
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| /** | ||
| * An `Elf64_Rela` structure, as described by the [System V ABI](https://refspecs.linuxfoundation.org/elf/gabi4+/ch4.reloc.html). | ||
| * The three fields `r_offset`, `r_info`, and `r_addend` are as described in the struct. | ||
| * The last two fields, `r_sym` and `r_type`, are extracted from the `r_info` value. | ||
| * | ||
| * The [ABI supplement for AArch64](https://github.com/ARM-software/abi-aa/blob/main/aaelf64/aaelf64.rst#relocation-types) | ||
| * provides information about the interpretation of the `r_type` values. | ||
| */ | ||
| case class Elf64Rela(r_offset: BigInt, r_info: BigInt, r_addend: BigInt, r_sym: Long, r_type: Long) | ||
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| // https://refspecs.linuxbase.org/elf/gabi4+/ch4.reloc.html | ||
| // https://github.com/ARM-software/abi-aa/blob/main/aaelf64/aaelf64.rst#relocation-types | ||
| protected def readRela(bs: AuxDecoder.Input) = | ||
| import AuxDecoder.* | ||
| val (r_offset, r_info, r_addend) = readTuple(readUint(64), readUint(64), readUint(64))(bs) | ||
| val r_sym = r_info >> 32 | ||
| val r_type = r_info & 0xffffffffL | ||
| Elf64Rela(r_offset, r_info, r_addend, r_sym.toLong, r_type.toLong) | ||
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| protected def parseRelaTab(bstr: ByteString) = | ||
| val bs = ByteArrayInputStream(bstr.toByteArray) | ||
| List.unfold(bs) { | ||
| case bs if bs.available() > 0 => Some(readRela(bs), bs) | ||
| case _ => None | ||
| } | ||
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| // see also: | ||
| // https://www.javadoc.io/doc/net.fornwall/jelf/latest/net/fornwall/jelf/ElfSymbol.html | ||
| // | ||
| // https://gist.github.com/x0nu11byt3/bcb35c3de461e5fb66173071a2379779 | ||
| // | ||
| // https://www.man7.org/linux/man-pages/man5/elf.5.html | ||
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| // Full ELF32 specification: https://refspecs.linuxfoundation.org/elf/elf.pdf | ||
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| // Full ELF64 specification: https://irix7.com/techpubs/007-4658-001.pdf | ||
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| /** | ||
| * https://refspecs.linuxfoundation.org/elf/elf.pdf | ||
| * Figure 1-7. Special Section Indexes | ||
| */ | ||
| protected def parseElfNdx(n: BigInt) = n.toInt match { | ||
| case 0 => ELFNDX.UND | ||
| case 0xfff1 => ELFNDX.ABS | ||
| case i => | ||
| if (i >= 0xff00) | ||
| Logger.warn("unhandled special elf section index: " + i) | ||
| ELFNDX.Section(i) | ||
| } | ||
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| /** | ||
| * https://github.com/ARM-software/abi-aa/blob/main/aaelf64/aaelf64.rst#dynamic-relocations | ||
| */ | ||
| def parseRela(rela: Elf64Rela) = | ||
| val sym = gtirb.symbolTables(".dynsym")(rela.r_sym.toInt).get | ||
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| rela.r_type match { | ||
| case 1025 | 1026 => Right(ExternalFunction(sym.name, rela.r_offset)) | ||
| case 1027 => Left((rela.r_offset, rela.r_addend)) | ||
| case 1024 => Left((BigInt(0), BigInt(0))) | ||
| } | ||
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| def getAllSymbols() = { | ||
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| gtirb.symbolEntriesByUuid | ||
| .flatMap { case (k, pos) => | ||
| val sym = k.get | ||
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| val idx = k.symTabIdx.collectFirst { case (".symtab", i) => | ||
| i.toInt | ||
| } | ||
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| val addr = k.getReferentAddress | ||
| val value = k.getScalarValue | ||
| val combinedValue = addr.orElse(value).getOrElse(0L) | ||
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| val (size, ty, bind, vis, shndx) = k.symEntry | ||
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| ty match { | ||
| case "NONE" => None | ||
| case ty => | ||
| Some( | ||
| ELFSymbol( | ||
| idx.getOrElse(-1), | ||
| combinedValue, | ||
| size.toInt, | ||
| ELFSymType.valueOf(ty), | ||
| ELFBind.valueOf(bind), | ||
| ELFVis.valueOf(vis), | ||
| parseElfNdx(shndx), | ||
| sym.name | ||
| ) | ||
| ) | ||
| } | ||
| } | ||
| .toList | ||
| .sortBy(x => x.num) | ||
| } | ||
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| def getRelocations() = { | ||
| val relaDyns = parseRelaTab(gtirb.sectionsByName(".rela.dyn").byteIntervals.head.contents) | ||
| val relaPlts = parseRelaTab(gtirb.sectionsByName(".rela.plt").byteIntervals.head.contents) | ||
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| val (offs, exts) = (relaDyns.view ++ relaPlts.view).partitionMap(parseRela) | ||
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| (offs.toMap, exts.toSet) | ||
| } | ||
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| def getGlobals() = { | ||
| gtirb.symbolEntriesByUuid.view.collect { case (symid, (size, "OBJECT", "GLOBAL", "DEFAULT", idx)) => | ||
| val blk = symid.getReferentUuid.get.getOption | ||
| // val sec = blk.section | ||
| // assert(gtirb.mod.sections(idx.toInt - 1) == sec) | ||
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| SpecGlobal(symid.get.name, (size * 8).toInt, None, blk.fold(BigInt(-1))(_.address)) | ||
| }.toSet | ||
| } | ||
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| def getFunctionEntries() = { | ||
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| gtirb.symbolEntriesByUuid.view.collect { | ||
| case (symid, (size, "FUNC", "GLOBAL", "DEFAULT", idx)) if idx != 0 => | ||
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| val nameSymbol = symid.get | ||
| val funcUuid = symid.getFunction.get | ||
| val entries = funcUuid.getEntries | ||
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| assert(entries.size == 1, "function with non-singular entry") | ||
| val entry = entries.head | ||
| val addr = entry.get.address | ||
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| FuncEntry(nameSymbol.name, (size * 8).toInt, addr) | ||
| }.toSet | ||
| } | ||
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| def getMainAddress(mainProcedureName: String) = { | ||
| gtirb.symbolsByName(mainProcedureName).getReferentUuid.get.get.address | ||
| } | ||
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| def getReadELFData(mainProcedureName: String) = { | ||
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| val syms = getAllSymbols() | ||
| val (offs, exts) = getRelocations() | ||
| val globs = getGlobals() | ||
| val funs = getFunctionEntries() | ||
| val main = getMainAddress(mainProcedureName) | ||
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| val x = SortedSet.from(exts)(Ordering.by(_.toString)) | ||
| ReadELFData(syms, x, SortedSet.from(globs), funs, offs, main) | ||
| } | ||
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| private val atSuffix = """@[A-Za-z_\d.]+$""".r | ||
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| /** | ||
| * Strips away some information from `readelf`'s [[translating.ReadELFData]] | ||
| * which is not so important and not produced by the GTIRB ELF loader. | ||
| * | ||
| * For example, this throws away symbols of type SECTION and symbols beginning with `$`. | ||
| * It also strips the `@GLIBC_XX.X` suffix from symbol names. | ||
| */ | ||
| def normaliseRelf(relf: ReadELFData) = { | ||
| val exts = relf.externalFunctions.map(x => x.copy(name = atSuffix.replaceFirstIn(x.name, ""))) | ||
| val syms = relf.symbolTable.flatMap { | ||
| case ELFSymbol(_, 0, 0, ELFSymType.FILE, ELFBind.LOCAL, ELFVis.DEFAULT, ELFNDX.ABS, "crtstuff.c") => None | ||
| case sym if sym.etype != ELFSymType.SECTION && sym.num != -1 && !sym.name.startsWith("$") => | ||
| Some(sym.copy(name = atSuffix.replaceFirstIn(sym.name, ""))) | ||
| case _ => None | ||
| } | ||
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| relf.copy(externalFunctions = exts, symbolTable = syms) | ||
| } | ||
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| /** | ||
| * Determines whether the current ReadELFData is compatible with | ||
| * a given reference ReadELFData. That is, whether the The given reference object is | ||
| * assumed to be the gold standard | ||
| */ | ||
| def checkReadELFCompatibility(gtirbRelf: ReadELFData, referenceRelf: ReadELFData): Boolean = { | ||
| var ok = true | ||
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| inline def check(b: Boolean, s: String) = { | ||
| if (!b) { | ||
| Logger.warn("PLEASE REPORT THIS ISSUE! include the gts and relf files. gtirb relf discrepancy, " + s) | ||
| ok = false | ||
| } | ||
| } | ||
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| inline def checkSet[T](x: Set[T], y: Set[T], s: String) = | ||
| check(x == y, s"$s:\ngtirb - relf = ${x -- y}\nrelf - gtirb = ${y -- x}") | ||
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| inline def checkEq(x: Any, y: Any, s: String) = | ||
| check(x == y, s"$s: gtirb: $x, readelf: $y}") | ||
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| val g = normaliseRelf(gtirbRelf) | ||
| val o = normaliseRelf(referenceRelf) | ||
| checkEq(g.mainAddress, o.mainAddress, "main address differs") | ||
| checkEq(g.functionEntries, o.functionEntries, "function entries differ") | ||
| checkEq(g.relocationOffsets, o.relocationOffsets, "relocations differ") | ||
| checkEq(g.globalVariables, o.globalVariables, "global variables differ") | ||
| checkSet(g.externalFunctions, o.externalFunctions, "external functions differ") | ||
| checkSet(g.symbolTable.toSet, o.symbolTable.toSet, "symbol tables differ") | ||
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| Logger.debug("gtirb relf and readelf relf compatible: " + ok) | ||
| ok | ||
| } | ||
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| } | ||
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Significant indentation 👎