Better retval+errno handling

netcon/NetconEthernetTap.cpp

@@ -447,13 +447,13 @@ void NetconEthernetTap::phyOnUnixData(PhySocket *sock,void **uptr,void *data,uns
  */
 int NetconEthernetTap::send_return_value(TcpConnection *conn, int retval, int _errno = 0)
 {
-  char retmsg[sizeof(retval) + sizeof(_errno)];
+	int sz = sizeof(char) + sizeof(retval) + sizeof(errno);
+  char retmsg[sz];
   memset(&retmsg, '\0', sizeof(retmsg));
   retmsg[0]=RPC_RETVAL;
-  memcpy(&retmsg[1], &retval, sizeof(retval));
+	memcpy(&retmsg[1], &retval, sizeof(retval));
 	memcpy(&retmsg[1]+sizeof(retval), &_errno, sizeof(_errno));
-	fprintf(stderr, "errno = %d\n", _errno);
-  int n = write(_phy.getDescriptor(conn->rpcSock), &retmsg, sizeof(retmsg));
+	int n = write(_phy.getDescriptor(conn->rpcSock), &retmsg, sz);
   if(n > 0)
     conn->pending = false;
   else {
@@ -695,8 +695,8 @@ err_t NetconEthernetTap::nc_connected(void *arg, struct tcp_pcb *tpcb, err_t err
 
 	[ ]	EACCES - The address is protected, and the user is not the superuser.
 	[X]	EADDRINUSE - The given address is already in use.
-	[ ]	EBADF - sockfd is not a valid descriptor.
-	[ ]	EINVAL - The socket is already bound to an address.
+	[X]	EBADF - sockfd is not a valid descriptor.
+	[X]	EINVAL - The socket is already bound to an address.
 	[ ]	ENOTSOCK - sockfd is a descriptor for a file, not a socket.
 	[ ]	The following errors are specific to UNIX domain (AF_UNIX) sockets:
 	[ ]	EACCES - Search permission is denied on a component of the path prefix. (See also path_resolution(7).)
@@ -704,16 +704,15 @@ err_t NetconEthernetTap::nc_connected(void *arg, struct tcp_pcb *tpcb, err_t err
 	[ ]	EFAULT - addr points outside the user's accessible address space.
 	[ ]	EINVAL - The addrlen is wrong, or the socket was not in the AF_UNIX family.
 	[ ]	ELOOP - Too many symbolic links were encountered in resolving addr.
-	[ ]	ENAMETOOLONG -s addr is too long.
+	[ ]	ENAMETOOLONG - s addr is too long.
 	[ ]	ENOENT - The file does not exist.
-	[ ]	ENOMEM - Insufficient kernel memory was available.
+	[X]	ENOMEM - Insufficient kernel memory was available.
 	[ ]	ENOTDIR - A component of the path prefix is not a directory.
 	[ ]	EROFS - The socket inode would reside on a read-only file system.
 
  */
 void NetconEthernetTap::handle_bind(PhySocket *sock, void **uptr, struct bind_st *bind_rpc)
 {
-	int _errno;
   struct sockaddr_in *connaddr;
   connaddr = (struct sockaddr_in *) &bind_rpc->addr;
   int conn_port = lwipstack->ntohs(connaddr->sin_port);
@@ -725,11 +724,6 @@ void NetconEthernetTap::handle_bind(PhySocket *sock, void **uptr, struct bind_st
   if(conn) {
     if(conn->pcb->state == CLOSED){
       int err = lwipstack->tcp_bind(conn->pcb, &conn_addr, conn_port);
-			send_return_value(conn, err, -99);
-      if(err == ERR_USE) {
-				_errno = EADDRINUSE;
-				send_return_value(conn, err, -99);
-			}
 			if(err != ERR_OK) {
 				int ip = connaddr->sin_addr.s_addr;
 				unsigned char d[4];
@@ -738,11 +732,20 @@ void NetconEthernetTap::handle_bind(PhySocket *sock, void **uptr, struct bind_st
 				d[2] = (ip >> 16) & 0xFF;
 				d[3] = (ip >> 24) & 0xFF;
 				fprintf(stderr, "handle_bind(): error binding to %d.%d.%d.%d : %d\n", d[0],d[1],d[2],d[3], conn_port);
-      }
+				if(err == ERR_USE)
+					send_return_value(conn, -1, EADDRINUSE);
+				if(err == ERR_MEM)
+					send_return_value(conn, -1, ENOMEM);
+			}
+			else {
+				send_return_value(conn, ERR_OK, 0); // OK
+			}
     }
     else fprintf(stderr, "handle_bind(): PCB not in CLOSED state. Ignoring BIND request.\n");
+		send_return_value(conn, -1, EINVAL);
   }
   else fprintf(stderr, "handle_bind(): can't locate connection for PCB\n");
+	send_return_value(conn, -1, EBADF);
 }
 
 /*

netcon/intercept.c

@@ -139,6 +139,11 @@ static char* af_sock_name  = "/tmp/.ztnc_e5cd7a9e1c5311ab";
 
 static int thispid;
 
+/*
+*
+* Check for forking
+*
+*/
 int checkpid() {
   if(thispid != getpid()) {
     printf("clone/fork detected. re-initializing this instance.\n");
@@ -149,6 +154,31 @@ int checkpid() {
   return 0;
 }
 
+/*
+*
+* Reads a return value from the service and sets errno (if applicable)
+*
+*/
+int get_retval()
+{
+  if(fdret_sock >= 0) {
+    int retval;
+    int sz = sizeof(char) + sizeof(retval) + sizeof(errno);
+    char retbuf[BUF_SZ];
+    memset(&retbuf, '\0', sz);
+    int n_read = read(fdret_sock, &retbuf, sz);
+    if(n_read > 0) {
+      memcpy(&retval, &retbuf[1], sizeof(retval));
+      memcpy(&errno, &retbuf[1+sizeof(retval)], sizeof(errno));
+      return retval;
+    }
+    else {
+      dwr("unable to read connect: return value\n");
+      return -1;
+    }
+  }
+}
+
 #define SLEEP_TIME 0
 
 /*------------------------------------------------------------------------------
@@ -474,7 +504,6 @@ int socket(SOCKET_SIG)
 {
 #ifdef DUMMY
   dwr("socket(fam=%d, type=%d, prot=%d)\n", socket_family, socket_type, protocol);
-  //usleep(DUMMY_WAIT);
   return realsocket(socket_family, socket_type, protocol);
 
 #else
@@ -676,33 +705,11 @@ int bind(BIND_SIG)
   write(fdret_sock, cmd, BUF_SZ);
   pthread_mutex_unlock(&lock);
 
-  /*
-    If we successfully wrote the RPC, try to read a return value
-     - Also get errno value
-  */
-  if(fdret_sock >= 0) {
-    int retval;
-    int _errno;
-    char mynewbuf[BUF_SZ];
-    memset(&mynewbuf, '\0', sizeof(mynewbuf));
-    int n_read = read(fdret_sock, &mynewbuf, sizeof(mynewbuf));
-    if(n_read > 0) {
-      memcpy(&retval, &mynewbuf[1], sizeof(retval));
-      memcpy(&_errno, &mynewbuf[1]+sizeof(retval), sizeof(_errno));
-      dwr("errno = %d\n", _errno);
-      errno = _errno;
-      pthread_mutex_unlock(&lock);
-      return retval;
-    }
-    else {
-      pthread_mutex_unlock(&lock);
-      dwr("unable to read connect: return value\n");
-    }
-  }
-  return 0; /* FIXME: get real return value */
+  return get_retval();
 #endif
 }
 
+
 /*------------------------------------------------------------------------------
 ----------------------------------- accept4() ----------------------------------
 ------------------------------------------------------------------------------*/