Type for mmap() / mmap2() system calls. More...

#include <memory.hxx>

Inheritance diagram for clues::MmapSystemCall:

Public Member Functions
	MmapSystemCall (const SystemCallNr nr)

bool	isOldMmap () const

Public Member Functions inherited from clues::SystemCall
	SystemCall (const SystemCallNr nr)
	Instantiates a new SystemCall object with given properties.

	SystemCall (const SystemCall &other)=delete

SystemCall &	operator= (const SystemCall &other)=delete

void	setEntryInfo (const Tracee &proc, const SystemCallInfo &info)
	Update the stored parameter values from the given tracee.

void	setExitInfo (const Tracee &proc, const SystemCallInfo &info)
	Update possible out and return parameter values from the given tracee.

std::string_view	name () const
	Returns the system call's human readable name.

size_t	numPars () const
	Returns the number of parameters for this system call.

SystemCallNr	callNr () const
	Returns the system call table number for this system call.

const ParameterVector &	parameters () const
	Access to the parameters associated with this system call.

SystemCallItemPtr	result () const
	Access to the return value parameter associated with this system call.

std::optional< ErrnoResult >	error () const
	Access to the errno result seen for this system call.

bool	hasOutParameter () const

bool	hasResultValue () const

bool	hasErrorCode () const

ABI	abi () const
	Returns the system call ABi seen during system call entry.

bool	is32BitEmulationABI () const

const SystemCallInfo *	currentInfo () const
	Access the current SystemCallInfo if currently processing syscall entry/exit.

Public Attributes
item::GenericPointerValue	hint

item::SizeValue	length

item::MemoryProtectionParameter	protection

item::MapFlagsParameter	flags

item::FileDescriptor	fd

item::OffsetValue	offset

std::optional< item::OldMmapArgs >	old_args

item::GenericPointerValue	addr

Protected Member Functions
void	prepareNewSystemCall () override
	Perform any necessary actions before processing a new system call entry event.

bool	implementsOldMmap () const

bool	check2ndPass (const Tracee &) override
	Check whether a second pass needs to be made processing parameters.

Protected Member Functions inherited from clues::SystemCall
void	fillParameters (const Tracee &proc, const SystemCallInfo &info)

void	setReturnItem (SystemCallItem &ret)
	Sets the return value system call item.

void	addParameters ()

template<typename T, typename... Targs>
void	addParameters (T &par, Targs &...rest)

template<typename... Targs>
void	setParameters (Targs &...args)

virtual void	updateFDTracking (const Tracee &proc)
	Update file descriptor tracking.

void	dropFD (const Tracee &proc, const cosmos::FileNum num)

void	trackFD (const Tracee &proc, FDInfo &&info)

Additional Inherited Members
Public Types inherited from clues::SystemCall
using	ParameterVector = std::vector<SystemCallItemPtr>
	Vector of the parameters required for a system call.

Static Public Member Functions inherited from clues::SystemCall
static const char *	name (const SystemCallNr nr)
	Returns the name of the given system call or "<unknown>" if unknown.

static bool	validNr (const SystemCallNr nr)
	Returns whether the given system call number is in a valid range.

Protected Attributes inherited from clues::SystemCall
SystemCallNr	m_nr
	The raw system call number of the system call.

const std::string_view	m_name
	The basic name of the system call.

const SystemCallInfo *	m_info = nullptr
	Current system call info during entry/exit processing, nullptr otherwise.

SystemCallItemPtr	m_return
	The return value of the system call.

std::optional< ErrnoResult >	m_error
	If the system call fails, this is the error code.

ParameterVector	m_pars
	The array of system call parameters, if any.

ABI	m_abi = ABI::UNKNOWN
	The current system call ABI which is in effect.

Detailed Description

Type for mmap() / mmap2() system calls.

SYS_mmap and SYS_mmap2 are unfortunate with regards to tracing. SYS_mmap can refer to two different variants of mmap() depending on ABI.

The well-known modern mmap() call taking six parameters is found in SYS_mmap on modern systems and in SYS_mmap2 on older ABIs.

SYS_mmap on older ABIs like I386 takes a single struct mmap_args parameter. Thus when SYS_mmap occurs during tracing, in an abstract application not considering the ABI, it can be either the modern mmap() or the legacy mmap(). To ease handling these differences, this type covers both SYS_mmap and SYS_mmap2 on all ABIs. Even on older ABIs the six members corresponding to the modern mmap() system call will be filled. This way applications can process both types of mmap system calls in a unified way.

For completeness, in case of the legacy SYS_mmap() the isOldMmap() member function will return true and the original data structure passed to the kernel is available in old_args.

Definition at line 48 of file memory.hxx.

Constructor & Destructor Documentation

◆ MmapSystemCall()

clues::MmapSystemCall::MmapSystemCall ( const SystemCallNr nr )

inlineexplicit

Definition at line 53 of file memory.hxx.

                                                       :
                        SystemCall{nr},
                        hint{"hint", "address placement hint"},
                        length{"len", "length"},
                        offset{"offset"},
                        addr{"addr", "mapped memory address", ItemType::RETVAL} {
                setReturnItem(addr);
        }

Member Function Documentation

◆ check2ndPass()

bool clues::MmapSystemCall::check2ndPass ( const Tracee & )

overrideprotectedvirtual

Check whether a second pass needs to be made processing parameters.

This function can be overridden by the actual system call implementation to perform context-sensitive evaluation of system call parameters (e.g. for ioctl() style system calls) upon system call entry.

The implementation of this function is allowed to modify the amount and types of system call parameters and return parameter. In this case true must be returned to let the base class implementation reevaluate all system call parameters.

Reimplemented from clues::SystemCall.

Definition at line 26 of file memory.cxx.

                                                    {
        /*
         * we use this callback not for rearranging the parameters, but for
         * synchronizing the regular mmap arguments with the legacy struct
         * mmap data.
         */
        if (isOldMmap()) {
                const auto &args = *old_args;
                hint.fill(proc, Word{cosmos::to_integral(args.addr())});
                length.fill(proc, Word{args.length()});
                protection.fill(proc, Word{static_cast<elf_greg_t>(args.prot().raw())});
                flags.fill(proc, Word{static_cast<elf_greg_t>(cosmos::to_integral(args.type()) | args.flags().raw())});
                fd.fill(proc, Word{static_cast<elf_greg_t>(cosmos::to_integral(args.fd()))});
                offset.fill(proc, Word{args.offset()});
        }
        return false;
}

◆ implementsOldMmap()

bool clues::MmapSystemCall::implementsOldMmap ( ) const

protected

Definition at line 6 of file memory.cxx.

                                             {
        switch (abi()) {
                case ABI::I386: return true;
                default: return false;
        }
}

◆ isOldMmap()

bool clues::MmapSystemCall::isOldMmap ( ) const

inline

Definition at line 62 of file memory.hxx.

                               {
                return old_args.has_value();
        }

◆ prepareNewSystemCall()

void clues::MmapSystemCall::prepareNewSystemCall ( )

overrideprotectedvirtual

Perform any necessary actions before processing a new system call entry event.

Reimplemented from clues::SystemCall.

Definition at line 13 of file memory.cxx.

                                          {
        /*
         * setup parameters for legacy / new variant of mmap()
         */
        if (callNr() == SystemCallNr::MMAP2 || !implementsOldMmap()) {
                old_args.reset();
                setParameters(hint, length, protection, flags, fd, offset);
        } else {
                old_args.emplace(item::OldMmapArgs{});
                setParameters(*old_args);
        }
}

Member Data Documentation

◆ addr

item::GenericPointerValue clues::MmapSystemCall::addr

Definition at line 88 of file memory.hxx.

◆ fd

item::FileDescriptor clues::MmapSystemCall::fd

Definition at line 81 of file memory.hxx.

◆ flags

item::MapFlagsParameter clues::MmapSystemCall::flags

Definition at line 80 of file memory.hxx.

◆ hint

item::GenericPointerValue clues::MmapSystemCall::hint

Definition at line 77 of file memory.hxx.

◆ length

item::SizeValue clues::MmapSystemCall::length

Definition at line 78 of file memory.hxx.

◆ offset

item::OffsetValue clues::MmapSystemCall::offset

Definition at line 82 of file memory.hxx.

◆ old_args

std::optional<item::OldMmapArgs> clues::MmapSystemCall::old_args

Definition at line 85 of file memory.hxx.

◆ protection

item::MemoryProtectionParameter clues::MmapSystemCall::protection

Definition at line 79 of file memory.hxx.

The documentation for this struct was generated from the following files:

include/syscalls/memory.hxx
src/syscalls/memory.cxx

Public Member Functions

Public Attributes

Protected Member Functions

Additional Inherited Members