Add process_path rule item (#51)

* process matching supports full path
* Remove strings.ToLower

route/rule_process_path.go

@@ -0,0 +1,51 @@
+package route
+
+import (
+	"strings"
+
+	"github.com/sagernet/sing-box/adapter"
+	"github.com/sagernet/sing-box/common/warning"
+	C "github.com/sagernet/sing-box/constant"
+)
+
+var warnProcessPathOnNonSupportedPlatform = warning.New(
+	func() bool { return !(C.IsLinux || C.IsWindows || C.IsDarwin) },
+	"rule item `process_path` is only supported on Linux, Windows and macOS",
+)
+
+var _ RuleItem = (*ProcessPathItem)(nil)
+
+type ProcessPathItem struct {
+	processes  []string
+	processMap map[string]bool
+}
+
+func NewProcessPathItem(processNameList []string) *ProcessPathItem {
+	warnProcessPathOnNonSupportedPlatform.Check()
+	rule := &ProcessPathItem{
+		processes:  processNameList,
+		processMap: make(map[string]bool),
+	}
+	for _, processName := range processNameList {
+		rule.processMap[processName] = true
+	}
+	return rule
+}
+
+func (r *ProcessPathItem) Match(metadata *adapter.InboundContext) bool {
+	if metadata.ProcessInfo == nil || metadata.ProcessInfo.ProcessPath == "" {
+		return false
+	}
+	return r.processMap[metadata.ProcessInfo.ProcessPath]
+}
+
+func (r *ProcessPathItem) String() string {
+	var description string
+	pLen := len(r.processes)
+	if pLen == 1 {
+		description = "process_path=" + r.processes[0]
+	} else {
+		description = "process_path=[" + strings.Join(r.processes, " ") + "]"
+	}
+	return description
+}