Enumerations
enum	ErrnoCheckState : unsigned { Irrelevant = 0 , MustBeChecked = 1 , MustNotBeChecked = 2 }
	Describe how reads and writes of `errno` are handled by the checker. More...

Functions
std::optional< SVal >	getErrnoValue (ProgramStateRef State)
	Returns the value of 'errno', if 'errno' was found in the AST.

ProgramStateRef	setErrnoValue (ProgramStateRef State, const LocationContext *LCtx, SVal Value, ErrnoCheckState EState)
	Set value of 'errno' to any SVal, if possible.

ProgramStateRef	setErrnoValue (ProgramStateRef State, CheckerContext &C, uint64_t Value, ErrnoCheckState EState)
	Set value of 'errno' to a concrete (signed) integer, if possible.

std::optional< Loc >	getErrnoLoc (ProgramStateRef State)
	Returns the location that points to the `MemoryRegion` where the 'errno' value is stored.

ErrnoCheckState	getErrnoState (ProgramStateRef State)
	Returns the errno check state, `Errno_Irrelevant` if 'errno' was not found (this is not the only case for that value).

ProgramStateRef	setErrnoState (ProgramStateRef State, ErrnoCheckState EState)
	Set the errno check state, do not modify the errno value.

ProgramStateRef	clearErrnoState (ProgramStateRef State)
	Clear state of errno (make it irrelevant).

bool	isErrno (const Decl *D)
	Determine if a `Decl` node related to 'errno'.

const char *	describeErrnoCheckState (ErrnoCheckState CS)
	Produce a textual description about how `errno` is allowed to be used (in a `ErrnoCheckState`).

const NoteTag *	getErrnoNoteTag (CheckerContext &C, const std::string &Message)
	Create a NoteTag that displays the message if the 'errno' memory region is marked as interesting, and resets the interestingness.

ProgramStateRef	setErrnoForStdSuccess (ProgramStateRef State, CheckerContext &C)
	Set errno state for the common case when a standard function is successful.

ProgramStateRef	setErrnoForStdFailure (ProgramStateRef State, CheckerContext &C, NonLoc ErrnoSym)
	Set errno state for the common case when a standard function fails.

ProgramStateRef	setErrnoStdMustBeChecked (ProgramStateRef State, CheckerContext &C, const Expr *InvalE)
	Set errno state for the common case when a standard function indicates failure only by `errno`.

const NoteTag *	getNoteTagForStdSuccess (CheckerContext &C, llvm::StringRef Fn)
	Generate the note tag that can be applied at the state generated by `setErrnoForStdSuccess` .

const NoteTag *	getNoteTagForStdMustBeChecked (CheckerContext &C, llvm::StringRef Fn)
	Generate the note tag that can be applied at the state generated by `setErrnoStdMustBeChecked` .

Enumeration Type Documentation

◆ ErrnoCheckState

enum clang::ento::errno_modeling::ErrnoCheckState : unsigned

Describe how reads and writes of errno are handled by the checker.

Enumerator

Irrelevant

We do not know anything about 'errno'.

Read and write is always allowed.

MustBeChecked

Value of 'errno' should be checked to find out if a previous function call has failed.

When this state is set errno must be read by the program before a next standard function call or other overwrite of errno follows, otherwise a bug report is emitted.

MustNotBeChecked

Value of 'errno' is not allowed to be read, it can contain an unspecified value.

When this state is set errno is not allowed to be read by the program until it is overwritten or invalidated.

Definition at line 26 of file ErrnoModeling.h.

Function Documentation

◆ clearErrnoState()

ProgramStateRef clang::ento::errno_modeling::clearErrnoState ( ProgramStateRef State )

Clear state of errno (make it irrelevant).

Definition at line 258 of file ErrnoModeling.cpp.

References Irrelevant, and setErrnoState().

◆ describeErrnoCheckState()

const char * clang::ento::errno_modeling::describeErrnoCheckState ( ErrnoCheckState CS )

Produce a textual description about how errno is allowed to be used (in a ErrnoCheckState).

The returned string is insertable into a longer warning message in the form "the value 'errno' <...>". Currently only the errno_modeling::MustNotBeChecked state is supported, others are not used by the clients.

Definition at line 272 of file ErrnoModeling.cpp.

References MustNotBeChecked.

Referenced by getNoteTagForStdSuccess().

◆ getErrnoLoc()

std::optional< Loc > clang::ento::errno_modeling::getErrnoLoc ( ProgramStateRef State )

Returns the location that points to the MemoryRegion where the 'errno' value is stored.

Returns std::nullopt if 'errno' was not found. Otherwise it always returns a valid memory region in the system global memory space.

Definition at line 243 of file ErrnoModeling.cpp.

◆ getErrnoNoteTag()

const NoteTag * clang::ento::errno_modeling::getErrnoNoteTag	(	CheckerContext &	C,
		const std::string &	Message
	)

Create a NoteTag that displays the message if the 'errno' memory region is marked as interesting, and resets the interestingness.

Definition at line 278 of file ErrnoModeling.cpp.

References clang::C, clang::ento::PathSensitiveBugReport::getErrorNode(), and clang::ento::PathSensitiveBugReport::isInteresting().

Referenced by getNoteTagForStdMustBeChecked(), and getNoteTagForStdSuccess().

◆ getErrnoState()

ErrnoCheckState clang::ento::errno_modeling::getErrnoState ( ProgramStateRef State )

Returns the errno check state, Errno_Irrelevant if 'errno' was not found (this is not the only case for that value).

Definition at line 250 of file ErrnoModeling.cpp.

◆ getErrnoValue()

std::optional< SVal > clang::ento::errno_modeling::getErrnoValue ( ProgramStateRef State )

Returns the value of 'errno', if 'errno' was found in the AST.

Definition at line 211 of file ErrnoModeling.cpp.

◆ getNoteTagForStdMustBeChecked()

const NoteTag * clang::ento::errno_modeling::getNoteTagForStdMustBeChecked	(	CheckerContext &	C,
		llvm::StringRef	Fn
	)

Generate the note tag that can be applied at the state generated by setErrnoStdMustBeChecked .

Fn Name of the (standard) function that is modeled.

Definition at line 328 of file ErrnoModeling.cpp.

References clang::C, and getErrnoNoteTag().

◆ getNoteTagForStdSuccess()

const NoteTag * clang::ento::errno_modeling::getNoteTagForStdSuccess	(	CheckerContext &	C,
		llvm::StringRef	Fn
	)

Generate the note tag that can be applied at the state generated by setErrnoForStdSuccess .

Fn Name of the (standard) function that is modeled.

Definition at line 320 of file ErrnoModeling.cpp.

References clang::C, describeErrnoCheckState(), getErrnoNoteTag(), and MustNotBeChecked.

◆ isErrno()

bool clang::ento::errno_modeling::isErrno ( const Decl * D )

Determine if a Decl node related to 'errno'.

This is true if the declaration is the errno variable or a function that returns a pointer to the 'errno' value (usually the 'errno' macro is defined with this function). D is not required to be a canonical declaration.

Definition at line 262 of file ErrnoModeling.cpp.

◆ setErrnoForStdFailure()

ProgramStateRef clang::ento::errno_modeling::setErrnoForStdFailure	(	ProgramStateRef	State,
		CheckerContext &	C,
		NonLoc	ErrnoSym
	)

Set errno state for the common case when a standard function fails.

Set errno value to be not equal to zero and ErrnoCheckState to Irrelevant . The irrelevant errno state ensures that no related bug report is emitted later and no note tag is needed.

ErrnoSym Value to be used for errno and constrained to be non-zero.

Definition at line 294 of file ErrnoModeling.cpp.

References clang::C, clang::ento::SVal::castAs(), clang::ento::SValBuilder::evalBinOp(), clang::ento::SValBuilder::getConditionType(), Irrelevant, clang::ento::SValBuilder::makeZeroVal(), and setErrnoValue().

◆ setErrnoForStdSuccess()

ProgramStateRef clang::ento::errno_modeling::setErrnoForStdSuccess	(	ProgramStateRef	State,
		CheckerContext &	C
	)

Set errno state for the common case when a standard function is successful.

Set ErrnoCheckState to MustNotBeChecked (the errno value is not affected). At the state transition a note tag created by getNoteTagForStdSuccess can be used.

Definition at line 289 of file ErrnoModeling.cpp.

References MustNotBeChecked, and setErrnoState().

◆ setErrnoState()

ProgramStateRef clang::ento::errno_modeling::setErrnoState	(	ProgramStateRef	State,
		ErrnoCheckState	EState
	)

Set the errno check state, do not modify the errno value.

Definition at line 254 of file ErrnoModeling.cpp.

Referenced by clearErrnoState(), setErrnoForStdSuccess(), setErrnoStateIrrelevant(), and setErrnoStdMustBeChecked().

◆ setErrnoStdMustBeChecked()

ProgramStateRef clang::ento::errno_modeling::setErrnoStdMustBeChecked	(	ProgramStateRef	State,
		CheckerContext &	C,
		const Expr *	InvalE
	)

Set errno state for the common case when a standard function indicates failure only by errno.

Sets ErrnoCheckState to MustBeChecked, and invalidates the errno region (clear of previous value). At the state transition a note tag created by getNoteTagForStdMustBeChecked can be used.

InvalE Expression that causes invalidation of errno.

Definition at line 307 of file ErrnoModeling.cpp.

References clang::C, MustBeChecked, and setErrnoState().

◆ setErrnoValue() [1/2]

ProgramStateRef clang::ento::errno_modeling::setErrnoValue	(	ProgramStateRef	State,
		CheckerContext &	C,
		uint64_t	Value,
		ErrnoCheckState	EState
	)

Set value of 'errno' to a concrete (signed) integer, if possible.

The errno check state is set always when the 'errno' value is set.

Definition at line 231 of file ErrnoModeling.cpp.

References clang::C.

◆ setErrnoValue() [2/2]

ProgramStateRef clang::ento::errno_modeling::setErrnoValue	(	ProgramStateRef	State,
		const LocationContext *	LCtx,
		SVal	Value,
		ErrnoCheckState	EState
	)

Set value of 'errno' to any SVal, if possible.