| //== PrintfFormatString.cpp - Analysis of printf format strings --*- C++ -*-==// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // Handling of format string in printf and friends. The structure of format |
| // strings for fprintf() are described in C99 7.19.6.1. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/Analysis/Analyses/FormatString.h" |
| #include "FormatStringParsing.h" |
| |
| using clang::analyze_format_string::ArgTypeResult; |
| using clang::analyze_format_string::FormatStringHandler; |
| using clang::analyze_format_string::LengthModifier; |
| using clang::analyze_format_string::OptionalAmount; |
| using clang::analyze_format_string::ConversionSpecifier; |
| using clang::analyze_printf::PrintfSpecifier; |
| |
| using namespace clang; |
| |
| typedef clang::analyze_format_string::SpecifierResult<PrintfSpecifier> |
| PrintfSpecifierResult; |
| |
| //===----------------------------------------------------------------------===// |
| // Methods for parsing format strings. |
| //===----------------------------------------------------------------------===// |
| |
| using analyze_format_string::ParseNonPositionAmount; |
| |
| static bool ParsePrecision(FormatStringHandler &H, PrintfSpecifier &FS, |
| const char *Start, const char *&Beg, const char *E, |
| unsigned *argIndex) { |
| if (argIndex) { |
| FS.setPrecision(ParseNonPositionAmount(Beg, E, *argIndex)); |
| } |
| else { |
| const OptionalAmount Amt = ParsePositionAmount(H, Start, Beg, E, |
| analyze_format_string::PrecisionPos); |
| if (Amt.isInvalid()) |
| return true; |
| FS.setPrecision(Amt); |
| } |
| return false; |
| } |
| |
| static PrintfSpecifierResult ParsePrintfSpecifier(FormatStringHandler &H, |
| const char *&Beg, |
| const char *E, |
| unsigned &argIndex) { |
| |
| using namespace clang::analyze_format_string; |
| using namespace clang::analyze_printf; |
| |
| const char *I = Beg; |
| const char *Start = 0; |
| UpdateOnReturn <const char*> UpdateBeg(Beg, I); |
| |
| // Look for a '%' character that indicates the start of a format specifier. |
| for ( ; I != E ; ++I) { |
| char c = *I; |
| if (c == '\0') { |
| // Detect spurious null characters, which are likely errors. |
| H.HandleNullChar(I); |
| return true; |
| } |
| if (c == '%') { |
| Start = I++; // Record the start of the format specifier. |
| break; |
| } |
| } |
| |
| // No format specifier found? |
| if (!Start) |
| return false; |
| |
| if (I == E) { |
| // No more characters left? |
| H.HandleIncompleteSpecifier(Start, E - Start); |
| return true; |
| } |
| |
| PrintfSpecifier FS; |
| if (ParseArgPosition(H, FS, Start, I, E)) |
| return true; |
| |
| if (I == E) { |
| // No more characters left? |
| H.HandleIncompleteSpecifier(Start, E - Start); |
| return true; |
| } |
| |
| // Look for flags (if any). |
| bool hasMore = true; |
| for ( ; I != E; ++I) { |
| switch (*I) { |
| default: hasMore = false; break; |
| case '-': FS.setIsLeftJustified(I); break; |
| case '+': FS.setHasPlusPrefix(I); break; |
| case ' ': FS.setHasSpacePrefix(I); break; |
| case '#': FS.setHasAlternativeForm(I); break; |
| case '0': FS.setHasLeadingZeros(I); break; |
| } |
| if (!hasMore) |
| break; |
| } |
| |
| if (I == E) { |
| // No more characters left? |
| H.HandleIncompleteSpecifier(Start, E - Start); |
| return true; |
| } |
| |
| // Look for the field width (if any). |
| if (ParseFieldWidth(H, FS, Start, I, E, |
| FS.usesPositionalArg() ? 0 : &argIndex)) |
| return true; |
| |
| if (I == E) { |
| // No more characters left? |
| H.HandleIncompleteSpecifier(Start, E - Start); |
| return true; |
| } |
| |
| // Look for the precision (if any). |
| if (*I == '.') { |
| ++I; |
| if (I == E) { |
| H.HandleIncompleteSpecifier(Start, E - Start); |
| return true; |
| } |
| |
| if (ParsePrecision(H, FS, Start, I, E, |
| FS.usesPositionalArg() ? 0 : &argIndex)) |
| return true; |
| |
| if (I == E) { |
| // No more characters left? |
| H.HandleIncompleteSpecifier(Start, E - Start); |
| return true; |
| } |
| } |
| |
| // Look for the length modifier. |
| if (ParseLengthModifier(FS, I, E) && I == E) { |
| // No more characters left? |
| H.HandleIncompleteSpecifier(Start, E - Start); |
| return true; |
| } |
| |
| if (*I == '\0') { |
| // Detect spurious null characters, which are likely errors. |
| H.HandleNullChar(I); |
| return true; |
| } |
| |
| // Finally, look for the conversion specifier. |
| const char *conversionPosition = I++; |
| ConversionSpecifier::Kind k = ConversionSpecifier::InvalidSpecifier; |
| switch (*conversionPosition) { |
| default: |
| break; |
| // C99: 7.19.6.1 (section 8). |
| case '%': k = ConversionSpecifier::PercentArg; break; |
| case 'A': k = ConversionSpecifier::AArg; break; |
| case 'E': k = ConversionSpecifier::EArg; break; |
| case 'F': k = ConversionSpecifier::FArg; break; |
| case 'G': k = ConversionSpecifier::GArg; break; |
| case 'X': k = ConversionSpecifier::XArg; break; |
| case 'a': k = ConversionSpecifier::aArg; break; |
| case 'c': k = ConversionSpecifier::cArg; break; |
| case 'd': k = ConversionSpecifier::dArg; break; |
| case 'e': k = ConversionSpecifier::eArg; break; |
| case 'f': k = ConversionSpecifier::fArg; break; |
| case 'g': k = ConversionSpecifier::gArg; break; |
| case 'i': k = ConversionSpecifier::iArg; break; |
| case 'n': k = ConversionSpecifier::nArg; break; |
| case 'o': k = ConversionSpecifier::oArg; break; |
| case 'p': k = ConversionSpecifier::pArg; break; |
| case 's': k = ConversionSpecifier::sArg; break; |
| case 'u': k = ConversionSpecifier::uArg; break; |
| case 'x': k = ConversionSpecifier::xArg; break; |
| // Mac OS X (unicode) specific |
| case 'C': k = ConversionSpecifier::CArg; break; |
| case 'S': k = ConversionSpecifier::SArg; break; |
| // Objective-C. |
| case '@': k = ConversionSpecifier::ObjCObjArg; break; |
| // Glibc specific. |
| case 'm': k = ConversionSpecifier::PrintErrno; break; |
| } |
| PrintfConversionSpecifier CS(conversionPosition, k); |
| FS.setConversionSpecifier(CS); |
| if (CS.consumesDataArgument() && !FS.usesPositionalArg()) |
| FS.setArgIndex(argIndex++); |
| |
| if (k == ConversionSpecifier::InvalidSpecifier) { |
| // Assume the conversion takes one argument. |
| return !H.HandleInvalidPrintfConversionSpecifier(FS, Start, I - Start); |
| } |
| return PrintfSpecifierResult(Start, FS); |
| } |
| |
| bool clang::analyze_format_string::ParsePrintfString(FormatStringHandler &H, |
| const char *I, |
| const char *E) { |
| |
| unsigned argIndex = 0; |
| |
| // Keep looking for a format specifier until we have exhausted the string. |
| while (I != E) { |
| const PrintfSpecifierResult &FSR = ParsePrintfSpecifier(H, I, E, argIndex); |
| // Did a fail-stop error of any kind occur when parsing the specifier? |
| // If so, don't do any more processing. |
| if (FSR.shouldStop()) |
| return true;; |
| // Did we exhaust the string or encounter an error that |
| // we can recover from? |
| if (!FSR.hasValue()) |
| continue; |
| // We have a format specifier. Pass it to the callback. |
| if (!H.HandlePrintfSpecifier(FSR.getValue(), FSR.getStart(), |
| I - FSR.getStart())) |
| return true; |
| } |
| assert(I == E && "Format string not exhausted"); |
| return false; |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Methods on ConversionSpecifier. |
| //===----------------------------------------------------------------------===// |
| const char *ConversionSpecifier::toString() const { |
| switch (kind) { |
| case dArg: return "d"; |
| case iArg: return "i"; |
| case oArg: return "o"; |
| case uArg: return "u"; |
| case xArg: return "x"; |
| case XArg: return "X"; |
| case fArg: return "f"; |
| case FArg: return "F"; |
| case eArg: return "e"; |
| case EArg: return "E"; |
| case gArg: return "g"; |
| case GArg: return "G"; |
| case aArg: return "a"; |
| case AArg: return "A"; |
| case cArg: return "c"; |
| case sArg: return "s"; |
| case pArg: return "p"; |
| case nArg: return "n"; |
| case PercentArg: return "%"; |
| case ScanListArg: return "["; |
| case InvalidSpecifier: return NULL; |
| |
| // MacOS X unicode extensions. |
| case CArg: return "C"; |
| case SArg: return "S"; |
| |
| // Objective-C specific specifiers. |
| case ObjCObjArg: return "@"; |
| |
| // GlibC specific specifiers. |
| case PrintErrno: return "m"; |
| } |
| return NULL; |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Methods on PrintfSpecifier. |
| //===----------------------------------------------------------------------===// |
| |
| ArgTypeResult PrintfSpecifier::getArgType(ASTContext &Ctx) const { |
| const PrintfConversionSpecifier &CS = getConversionSpecifier(); |
| |
| if (!CS.consumesDataArgument()) |
| return ArgTypeResult::Invalid(); |
| |
| if (CS.getKind() == ConversionSpecifier::cArg) |
| switch (LM.getKind()) { |
| case LengthModifier::None: return Ctx.IntTy; |
| case LengthModifier::AsLong: return ArgTypeResult::WIntTy; |
| default: |
| return ArgTypeResult::Invalid(); |
| } |
| |
| if (CS.isIntArg()) |
| switch (LM.getKind()) { |
| case LengthModifier::AsLongDouble: |
| return ArgTypeResult::Invalid(); |
| case LengthModifier::None: return Ctx.IntTy; |
| case LengthModifier::AsChar: return Ctx.SignedCharTy; |
| case LengthModifier::AsShort: return Ctx.ShortTy; |
| case LengthModifier::AsLong: return Ctx.LongTy; |
| case LengthModifier::AsLongLong: return Ctx.LongLongTy; |
| case LengthModifier::AsIntMax: |
| // FIXME: Return unknown for now. |
| return ArgTypeResult(); |
| case LengthModifier::AsSizeT: return Ctx.getSizeType(); |
| case LengthModifier::AsPtrDiff: return Ctx.getPointerDiffType(); |
| } |
| |
| if (CS.isUIntArg()) |
| switch (LM.getKind()) { |
| case LengthModifier::AsLongDouble: |
| return ArgTypeResult::Invalid(); |
| case LengthModifier::None: return Ctx.UnsignedIntTy; |
| case LengthModifier::AsChar: return Ctx.UnsignedCharTy; |
| case LengthModifier::AsShort: return Ctx.UnsignedShortTy; |
| case LengthModifier::AsLong: return Ctx.UnsignedLongTy; |
| case LengthModifier::AsLongLong: return Ctx.UnsignedLongLongTy; |
| case LengthModifier::AsIntMax: |
| // FIXME: Return unknown for now. |
| return ArgTypeResult(); |
| case LengthModifier::AsSizeT: |
| // FIXME: How to get the corresponding unsigned |
| // version of size_t? |
| return ArgTypeResult(); |
| case LengthModifier::AsPtrDiff: |
| // FIXME: How to get the corresponding unsigned |
| // version of ptrdiff_t? |
| return ArgTypeResult(); |
| } |
| |
| if (CS.isDoubleArg()) { |
| if (LM.getKind() == LengthModifier::AsLongDouble) |
| return Ctx.LongDoubleTy; |
| return Ctx.DoubleTy; |
| } |
| |
| switch (CS.getKind()) { |
| case ConversionSpecifier::sArg: |
| return ArgTypeResult(LM.getKind() == LengthModifier::AsWideChar ? |
| ArgTypeResult::WCStrTy : ArgTypeResult::CStrTy); |
| case ConversionSpecifier::SArg: |
| // FIXME: This appears to be Mac OS X specific. |
| return ArgTypeResult::WCStrTy; |
| case ConversionSpecifier::CArg: |
| return Ctx.WCharTy; |
| case ConversionSpecifier::pArg: |
| return ArgTypeResult::CPointerTy; |
| default: |
| break; |
| } |
| |
| // FIXME: Handle other cases. |
| return ArgTypeResult(); |
| } |
| |
| bool PrintfSpecifier::fixType(QualType QT) { |
| // Handle strings first (char *, wchar_t *) |
| if (QT->isPointerType() && (QT->getPointeeType()->isAnyCharacterType())) { |
| CS.setKind(ConversionSpecifier::sArg); |
| |
| // Disable irrelevant flags |
| HasAlternativeForm = 0; |
| HasLeadingZeroes = 0; |
| |
| // Set the long length modifier for wide characters |
| if (QT->getPointeeType()->isWideCharType()) |
| LM.setKind(LengthModifier::AsWideChar); |
| |
| return true; |
| } |
| |
| // We can only work with builtin types. |
| if (!QT->isBuiltinType()) |
| return false; |
| |
| // Everything else should be a base type |
| const BuiltinType *BT = QT->getAs<BuiltinType>(); |
| |
| // Set length modifier |
| switch (BT->getKind()) { |
| default: |
| // The rest of the conversions are either optional or for non-builtin types |
| LM.setKind(LengthModifier::None); |
| break; |
| |
| case BuiltinType::Char_U: |
| case BuiltinType::UChar: |
| case BuiltinType::Char_S: |
| case BuiltinType::SChar: |
| LM.setKind(LengthModifier::AsChar); |
| break; |
| |
| case BuiltinType::Short: |
| case BuiltinType::UShort: |
| LM.setKind(LengthModifier::AsShort); |
| break; |
| |
| case BuiltinType::WChar_S: |
| case BuiltinType::WChar_U: |
| case BuiltinType::Long: |
| case BuiltinType::ULong: |
| LM.setKind(LengthModifier::AsLong); |
| break; |
| |
| case BuiltinType::LongLong: |
| case BuiltinType::ULongLong: |
| LM.setKind(LengthModifier::AsLongLong); |
| break; |
| |
| case BuiltinType::LongDouble: |
| LM.setKind(LengthModifier::AsLongDouble); |
| break; |
| } |
| |
| // Set conversion specifier and disable any flags which do not apply to it. |
| // Let typedefs to char fall through to int, as %c is silly for uint8_t. |
| if (isa<TypedefType>(QT) && QT->isAnyCharacterType()) { |
| CS.setKind(ConversionSpecifier::cArg); |
| LM.setKind(LengthModifier::None); |
| Precision.setHowSpecified(OptionalAmount::NotSpecified); |
| HasAlternativeForm = 0; |
| HasLeadingZeroes = 0; |
| HasPlusPrefix = 0; |
| } |
| // Test for Floating type first as LongDouble can pass isUnsignedIntegerType |
| else if (QT->isRealFloatingType()) { |
| CS.setKind(ConversionSpecifier::fArg); |
| } |
| else if (QT->isPointerType()) { |
| CS.setKind(ConversionSpecifier::pArg); |
| Precision.setHowSpecified(OptionalAmount::NotSpecified); |
| HasAlternativeForm = 0; |
| HasLeadingZeroes = 0; |
| HasPlusPrefix = 0; |
| } |
| else if (QT->isSignedIntegerType()) { |
| CS.setKind(ConversionSpecifier::dArg); |
| HasAlternativeForm = 0; |
| } |
| else if (QT->isUnsignedIntegerType()) { |
| CS.setKind(ConversionSpecifier::uArg); |
| HasAlternativeForm = 0; |
| HasPlusPrefix = 0; |
| } |
| else { |
| return false; |
| } |
| |
| return true; |
| } |
| |
| void PrintfSpecifier::toString(llvm::raw_ostream &os) const { |
| // Whilst some features have no defined order, we are using the order |
| // appearing in the C99 standard (ISO/IEC 9899:1999 (E) ยค7.19.6.1) |
| os << "%"; |
| |
| // Positional args |
| if (usesPositionalArg()) { |
| os << getPositionalArgIndex() << "$"; |
| } |
| |
| // Conversion flags |
| if (IsLeftJustified) os << "-"; |
| if (HasPlusPrefix) os << "+"; |
| if (HasSpacePrefix) os << " "; |
| if (HasAlternativeForm) os << "#"; |
| if (HasLeadingZeroes) os << "0"; |
| |
| // Minimum field width |
| FieldWidth.toString(os); |
| // Precision |
| Precision.toString(os); |
| // Length modifier |
| os << LM.toString(); |
| // Conversion specifier |
| os << CS.toString(); |
| } |
| |
| bool PrintfSpecifier::hasValidPlusPrefix() const { |
| if (!HasPlusPrefix) |
| return true; |
| |
| // The plus prefix only makes sense for signed conversions |
| switch (CS.getKind()) { |
| case ConversionSpecifier::dArg: |
| case ConversionSpecifier::iArg: |
| case ConversionSpecifier::fArg: |
| case ConversionSpecifier::FArg: |
| case ConversionSpecifier::eArg: |
| case ConversionSpecifier::EArg: |
| case ConversionSpecifier::gArg: |
| case ConversionSpecifier::GArg: |
| case ConversionSpecifier::aArg: |
| case ConversionSpecifier::AArg: |
| return true; |
| |
| default: |
| return false; |
| } |
| } |
| |
| bool PrintfSpecifier::hasValidAlternativeForm() const { |
| if (!HasAlternativeForm) |
| return true; |
| |
| // Alternate form flag only valid with the oxXaAeEfFgG conversions |
| switch (CS.getKind()) { |
| case ConversionSpecifier::oArg: |
| case ConversionSpecifier::xArg: |
| case ConversionSpecifier::XArg: |
| case ConversionSpecifier::aArg: |
| case ConversionSpecifier::AArg: |
| case ConversionSpecifier::eArg: |
| case ConversionSpecifier::EArg: |
| case ConversionSpecifier::fArg: |
| case ConversionSpecifier::FArg: |
| case ConversionSpecifier::gArg: |
| case ConversionSpecifier::GArg: |
| return true; |
| |
| default: |
| return false; |
| } |
| } |
| |
| bool PrintfSpecifier::hasValidLeadingZeros() const { |
| if (!HasLeadingZeroes) |
| return true; |
| |
| // Leading zeroes flag only valid with the diouxXaAeEfFgG conversions |
| switch (CS.getKind()) { |
| case ConversionSpecifier::dArg: |
| case ConversionSpecifier::iArg: |
| case ConversionSpecifier::oArg: |
| case ConversionSpecifier::uArg: |
| case ConversionSpecifier::xArg: |
| case ConversionSpecifier::XArg: |
| case ConversionSpecifier::aArg: |
| case ConversionSpecifier::AArg: |
| case ConversionSpecifier::eArg: |
| case ConversionSpecifier::EArg: |
| case ConversionSpecifier::fArg: |
| case ConversionSpecifier::FArg: |
| case ConversionSpecifier::gArg: |
| case ConversionSpecifier::GArg: |
| return true; |
| |
| default: |
| return false; |
| } |
| } |
| |
| bool PrintfSpecifier::hasValidSpacePrefix() const { |
| if (!HasSpacePrefix) |
| return true; |
| |
| // The space prefix only makes sense for signed conversions |
| switch (CS.getKind()) { |
| case ConversionSpecifier::dArg: |
| case ConversionSpecifier::iArg: |
| case ConversionSpecifier::fArg: |
| case ConversionSpecifier::FArg: |
| case ConversionSpecifier::eArg: |
| case ConversionSpecifier::EArg: |
| case ConversionSpecifier::gArg: |
| case ConversionSpecifier::GArg: |
| case ConversionSpecifier::aArg: |
| case ConversionSpecifier::AArg: |
| return true; |
| |
| default: |
| return false; |
| } |
| } |
| |
| bool PrintfSpecifier::hasValidLeftJustified() const { |
| if (!IsLeftJustified) |
| return true; |
| |
| // The left justified flag is valid for all conversions except n |
| switch (CS.getKind()) { |
| case ConversionSpecifier::nArg: |
| return false; |
| |
| default: |
| return true; |
| } |
| } |
| |
| bool PrintfSpecifier::hasValidPrecision() const { |
| if (Precision.getHowSpecified() == OptionalAmount::NotSpecified) |
| return true; |
| |
| // Precision is only valid with the diouxXaAeEfFgGs conversions |
| switch (CS.getKind()) { |
| case ConversionSpecifier::dArg: |
| case ConversionSpecifier::iArg: |
| case ConversionSpecifier::oArg: |
| case ConversionSpecifier::uArg: |
| case ConversionSpecifier::xArg: |
| case ConversionSpecifier::XArg: |
| case ConversionSpecifier::aArg: |
| case ConversionSpecifier::AArg: |
| case ConversionSpecifier::eArg: |
| case ConversionSpecifier::EArg: |
| case ConversionSpecifier::fArg: |
| case ConversionSpecifier::FArg: |
| case ConversionSpecifier::gArg: |
| case ConversionSpecifier::GArg: |
| case ConversionSpecifier::sArg: |
| return true; |
| |
| default: |
| return false; |
| } |
| } |
| bool PrintfSpecifier::hasValidFieldWidth() const { |
| if (FieldWidth.getHowSpecified() == OptionalAmount::NotSpecified) |
| return true; |
| |
| // The field width is valid for all conversions except n |
| switch (CS.getKind()) { |
| case ConversionSpecifier::nArg: |
| return false; |
| |
| default: |
| return true; |
| } |
| } |