108 lines
2.7 KiB
Go
108 lines
2.7 KiB
Go
// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
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// SPDX-License-Identifier: BSD-3-Clause
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//go:build linux && amd64
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package debug
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import (
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"fmt"
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"os"
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"runtime"
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"syscall"
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"unsafe"
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"sourcedock.dev/petrbalvin/gasm-devkit/asm"
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"sourcedock.dev/petrbalvin/gasm-devkit/parser"
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"sourcedock.dev/petrbalvin/gasm-devkit/verify"
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)
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// RunTarget is the debuggee entry point (gasm debug --target).
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func RunTarget(asmPath, funcName, argsFile, tmpDir string) error {
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src, err := os.ReadFile(asmPath)
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if err != nil {
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return fmt.Errorf("debug target: %w", err)
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}
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file, errs := parser.Parse(asmPath, string(src))
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if len(errs) > 0 {
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return fmt.Errorf("debug target: parse: %v", errs[0])
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}
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img, err := asm.AssembleFile(file)
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if err != nil {
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return fmt.Errorf("debug target: assemble: %w", err)
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}
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var fl *asm.FuncLayout
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for i := range img.Funcs {
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if img.Funcs[i].Name == funcName {
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fl = &img.Funcs[i]
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break
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}
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}
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if fl == nil {
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return fmt.Errorf("debug target: function %q not found", funcName)
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}
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code := img.Bytes()
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exec, err := mapRWX(code)
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if err != nil {
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return fmt.Errorf("debug target: mmap: %w", err)
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}
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codeBase := uintptr(unsafe.Pointer(&exec[0]))
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if err := os.WriteFile(tmpDir+"/codebase", []byte(fmt.Sprintf("%d", codeBase)), 0o644); err != nil {
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return fmt.Errorf("debug target: write codebase: %w", err)
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}
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meta := fmt.Sprintf("%d %d %d", fl.Offset, fl.Size, fl.Args)
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os.WriteFile(tmpDir+"/funcmeta", []byte(meta), 0o644)
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labelsFile, _ := os.Create(tmpDir + "/labels")
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if labelsFile != nil {
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for label, off := range fl.Labels {
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fmt.Fprintf(labelsFile, "%s %d\n", label, off)
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}
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labelsFile.Close()
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}
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args, err := os.ReadFile(argsFile)
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if err != nil {
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return fmt.Errorf("debug target: read args: %w", err)
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}
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if len(args) < fl.Args {
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padded := make([]byte, fl.Args)
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copy(padded, args)
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args = padded
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}
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bufSpecFile := tmpDir + "/bufspec"
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if bufSpec, err := os.ReadFile(bufSpecFile); err == nil && len(bufSpec) > 0 {
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args, err = setupBuffers(string(bufSpec), args, fl.Args, tmpDir)
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if err != nil {
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return fmt.Errorf("debug target: setup buffers: %w", err)
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}
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}
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runtime.LockOSThread()
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if _, _, errno := syscall.Syscall(syscall.SYS_PTRACE, uintptr(syscall.PTRACE_TRACEME), 0, 0); errno != 0 {
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return fmt.Errorf("debug target: PTRACE_TRACEME: %v", errno)
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}
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os.WriteFile(tmpDir+"/ready", []byte("ok"), 0o644)
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syscall.Kill(syscall.Getpid(), syscall.SIGSTOP)
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os.WriteFile(tmpDir+"/entry", []byte("ok"), 0o644)
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syscall.Kill(syscall.Getpid(), syscall.SIGSTOP)
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fnAddr := codeBase + uintptr(fl.Offset)
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stackArgs := make([]byte, fl.Args)
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copy(stackArgs, args)
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_, callErr := verify.Call(fnAddr, stackArgs)
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if callErr != nil {
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os.Exit(1)
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}
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os.Exit(0)
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return nil
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}
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