refactor!: remove direct syscall support

acheron.go

@@ -1,6 +1,8 @@
 package acheron
 
 import (
+	"fmt"
+
 	"github.com/f1zm0/acheron/internal/resolver"
 	"github.com/f1zm0/acheron/internal/resolver/rvasort"
 	"github.com/f1zm0/acheron/pkg/hashing"
@@ -19,6 +21,9 @@ type options struct {
 	hashFunction hashing.HashFunction
 }
 
+// stub for asm implementation
+func execIndirectSyscall(ssn uint16, gateAddr uintptr, argh ...uintptr) (errcode uint32)
+
 // New returns a new Acheron instance with the given options, or an error if initialization fails.
 func New(opts ...Option) (*Acheron, error) {
 	options := &options{
@@ -49,3 +54,20 @@ func WithHashFunction(f hashing.HashFunction) Option {
 func (a *Acheron) HashString(s string) uint64 {
 	return a.hashFunction([]byte(s))
 }
+
+// GetSyscall returns the Syscall struct for the given function hash.
+func (a *Acheron) GetSyscall(fnHash uint64) (*resolver.Syscall, error) {
+	return a.resolver.GetSyscall(fnHash)
+}
+
+// Syscall executes an indirect syscall with the given function hash and arguments. Returns the error code if it fails.
+func (a *Acheron) Syscall(fnHash uint64, args ...uintptr) error {
+	sys, err := a.resolver.GetSyscall(fnHash)
+	if err != nil {
+		return err
+	}
+	if errCode := execIndirectSyscall(sys.SSN, sys.TrampolineAddr, args...); errCode < 0 { // !NT_SUCCESS
+		return fmt.Errorf("syscall failed with error code %d", errCode)
+	}
+	return nil
+}

syscall_amd64.s

@@ -10,7 +10,7 @@
 
 
 // func execIndirectSyscall(ssn uint16, trampoline uintptr, argh ...uintptr) (errcode uint32)
-TEXT ·execIndirectSyscall(SB),NOSPLIT, $0-32
+TEXT ·execIndirectSyscall(SB),NOSPLIT, $0-144
     XORQ    AX, AX
     MOVW    ssn+0(FP), AX
 
@@ -81,74 +81,3 @@ jumpcall:
     POPQ	CX
     MOVL	AX, errcode+40(FP)
     RET
-
-
-// func execDirectSyscall(ssn uint16, trampoline uintptr, argh ...uintptr) (errcode uint32)
-TEXT ·execDirectSyscall(SB),NOSPLIT, $0-32
-    XORQ    AX, AX
-    MOVW    ssn+0(FP), AX
-
-    PUSHQ   CX
-
-    //put variadic pointer into SI
-    MOVQ    argh_base+16(FP),SI
-
-    //put variadic size into CX
-    MOVQ    argh_len+24(FP),CX
-
-    // SetLastError(0).
-    MOVQ    0x30(GS), DI
-    MOVL    $0, 0x68(DI)
-
-    // room for args
-    SUBQ    $(maxargs*8), SP	
-
-    //no parameters, special case
-    CMPL    CX, $0
-    JLE     jumpcall
-
-    // Fast version, do not store args on the stack.
-    CMPL    CX, $4
-    JLE	    loadregs
-
-    // Check we have enough room for args.
-    CMPL    CX, $maxargs
-    JLE	    2(PC)
-
-    // not enough room -> crash
-    INT	    $3			
-
-    // Copy args to the stack.
-    MOVQ    SP, DI
-    CLD
-    REP; MOVSQ
-    MOVQ    SP, SI
-
-loadregs:
-
-    // Load first 4 args into correspondent registers.
-    MOVQ	0(SI), CX
-    MOVQ	8(SI), DX
-    MOVQ	16(SI), R8
-    MOVQ	24(SI), R9
-
-    // Floating point arguments are passed in the XMM registers
-    // Set them here in case any of the arguments are floating point values. 
-    // For details see: https://msdn.microsoft.com/en-us/library/zthk2dkh.aspx
-    MOVQ	CX, X0
-    MOVQ	DX, X1
-    MOVQ	R8, X2
-    MOVQ	R9, X3
-
-jumpcall:
-    MOVQ    CX, R10
-
-    // direcy syscall
-    SYSCALL
-
-    ADDQ	$((maxargs)*8), SP
-
-    // Return result
-    POPQ	CX
-    MOVL	AX, errcode+40(FP)
-    RET