futex.hxx

#pragma once
 
// Linux
#include <linux/futex.h> // futex(2)
 
// cosmos
#include <cosmos/BitMask.hxx>
 
// clues
#include <clues/items/items.hxx>
 
namespace clues::item {


class CLUES_API FutexOperation :
                public ValueInParameter {
public: // types
 
        enum class Command : int {
                WAIT            = FUTEX_WAIT, /* wait for `val` to be changed */
                WAKE            = FUTEX_WAKE, /* wake given number of waiters */
                WAIT_REQUEUE_PI = FUTEX_WAIT_REQUEUE_PI, /* wait on a non-PI futex, potentially being requeued to a PI futex on addr2 */
                CREATE_FD       = FUTEX_FD, /* create a futex FD, dropped in Linux 2.6.25 */
                REQUEUE         = FUTEX_REQUEUE, /* wakeup some waiters, requeue others */
                CMP_REQUEUE     = FUTEX_CMP_REQUEUE, /* additionally compare futex value */
                CMP_REQUEUE_PI  = FUTEX_CMP_REQUEUE_PI, /* CMP_REQUEUE with priority-inheritance semantics. `val1` must be 1. */
                WAKE_OP         = FUTEX_WAKE_OP, /* wake up waiters based on provided criteria */
                WAIT_BITSET     = FUTEX_WAIT_BITSET, /* wait based on a 32-bit bitset limiting wakeups */
                WAKE_BITSET     = FUTEX_WAKE_BITSET, /* wake up waiters with matching bits in a 32-bit bitset */
                LOCK_PI         = FUTEX_LOCK_PI, /* priority-inheritance lock operation */
                LOCK_PI2        = FUTEX_LOCK_PI2, /* save as above, but supports Flag::REALTIME on top */
                TRYLOCK_PI      = FUTEX_TRYLOCK_PI, /* try to lock the futex based on extra kernel information, does not block */
                UNLOCK_PI       = FUTEX_UNLOCK_PI, /* unlock with priority inheritance semantics */
        };
 
        enum class Flag : int {
                PRIVATE_FLAG = FUTEX_PRIVATE_FLAG, /* futex between threads only */
                REALTIME = FUTEX_CLOCK_REALTIME, /* for wait related operations, use CLOCK_REALTIME instead of MONOTONIC */
        };
 
        using Flags = cosmos::BitMask<Flag>;
 
public: // functions
 
        explicit FutexOperation() :
                        ValueInParameter{"op", "futex operation"} {
        }
 
        std::string str() const override;
 
        void processValue(const Tracee &) override;
 
        auto command() const {
                return m_cmd;
        }
 
        auto flags() const {
                return m_flags;
        }
 
protected: // data
 
        Command m_cmd = Command{0};
        Flags m_flags;
};


class CLUES_API FutexWakeOperation :
                public ValueInParameter {
public: // types

        enum class Operation : uint32_t {
                SET  = FUTEX_OP_SET,  
                ADD  = FUTEX_OP_ADD,  
                OR   = FUTEX_OP_OR,   
                ANDN = FUTEX_OP_ANDN, 
                XOR  = FUTEX_OP_XOR,  
        };
 
        enum class Comparator : uint32_t {
                EQUAL         = FUTEX_OP_CMP_EQ,  
                UNEQUAL       = FUTEX_OP_CMP_NE,  
                LESS_THAN     = FUTEX_OP_CMP_LT,  
                LESS_EQUAL    = FUTEX_OP_CMP_LE,  
                GREATER_THAN  = FUTEX_OP_CMP_GT,  
                GREATER_EQUAL = FUTEX_OP_CMP_GE,  
        };
 
public: // functions
 
        explicit FutexWakeOperation() :
                        ValueInParameter{"wake_op", "wake operation settings"} {
        }
 
        std::string str() const override;
 
        void processValue(const Tracee &) override;
 
        auto operation() const {
                return m_op;
        }
 
        auto comparator() const {
                return m_comp;
        }
 
        bool doShiftArg() const {
                return m_shift_arg;
        }
 
        uint32_t oparg() const {
                return m_oparg;
        }
 
        uint32_t cmparg() const {
                return m_cmparg;
        }
 
protected: // data
 
        Operation m_op = Operation{0};
        Comparator m_comp = Comparator{0};
        bool m_shift_arg = false;
        uint32_t m_oparg = 0;
        uint32_t m_cmparg = 0;
};
 
} // end ns