now based on unix socket and json config

cgproxy.cpp

@@ -0,0 +1,31 @@
+#include <nlohmann/json.hpp>
+#include "socket_client.h"
+using json = nlohmann::json;
+using namespace CGPROXY;
+
+bool attach2cgproxy(){
+    pid_t pid=getpid();
+    json j;
+    j["type"] = MSG_TYPE_PROXY_PID;
+    j["data"] = pid;
+    int status;
+    SOCKET::send(j.dump(), status);
+    return status==0;
+}
+
+int main(int argc, char *argv[]){
+    int shift=1;
+    // if (argc==1){
+    //     error("usage: cgproxy [--debug] <CMD>\nexample: cgroxy curl -I https://www.google.com");
+    //     exit(EXIT_FAILURE);
+    // }
+    processArgs(argc,argv,shift);
+    
+    if (!attach2cgproxy()){
+        error("attach process failed");
+        exit(EXIT_FAILURE);
+    }
+
+    string s=join2str(argc-shift,argv+shift,' ');
+    return system(s.c_str());
+}