Fix struct sockaddr/sockaddr_in/sockaddr_un strict aliasing violations

Building gdbserver in C++ mode shows:

  gdb/gdbserver/tracepoint.c: In function ‘void* gdb_agent_helper_thread(void*)’:
  gdb/gdbserver/tracepoint.c:7190:47: error: cannot convert ‘sockaddr_un*’ to ‘sockaddr*’ for argument ‘2’ to ‘int accept(int, sockaddr*, socklen_t*)’
	  fd = accept (listen_fd, &sockaddr, &tmp);

A few places in the tree already have an explicit cast to struct
sockaddr *, but that's a strict aliasing violation.  Instead of
propagating invalid code, fix this by using a union instead.

gdb/ChangeLog:
2015-03-07  Pedro Alves  <palves@redhat.com>

	* common/gdb_socket.h: New file.
	* ser-tcp.c: Include gdb_socket.h.  Don't include netinet/in.h nor
	sys/socket.h.
	(net_open): Use union gdb_sockaddr_u.

gdb/gdbserver/ChangeLog:
2015-03-07  Pedro Alves  <palves@redhat.com>

	* gdbreplay.c: No longer include <netinet/in.h>, <sys/socket.h>,
	or <winsock2.h> here.  Instead include "gdb_socket.h".
	(remote_open): Use union gdb_sockaddr_u.
	* remote-utils.c: No longer include <netinet/in.h>, <sys/socket.h>
	or <winsock2.h> here.  Instead include "gdb_socket.h".
	(handle_accept_event, remote_prepare): Use union gdb_sockaddr_u.
	* tracepoint.c: Include "gdb_socket.h" instead of <sys/socket.h>
	or <sys/un.h>.
	(init_named_socket, gdb_agent_helper_thread): Use union
	gdb_sockaddr_u.

1 files changed, 10 insertions, 19 deletions

diff --git a/gdb/gdbserver/remote-utils.c b/gdb/gdbserver/remote-utils.c
index 1de86beecfb..69f87bd27fc 100644
--- a/gdb/gdbserver/remote-utils.c
+++ b/gdb/gdbserver/remote-utils.c
@@ -30,12 +30,6 @@
 #if HAVE_SYS_FILE_H
 #include <sys/file.h>
 #endif
-#if HAVE_NETINET_IN_H
-#include <netinet/in.h>
-#endif
-#if HAVE_SYS_SOCKET_H
-#include <sys/socket.h>
-#endif
 #if HAVE_NETDB_H
 #include <netdb.h>
 #endif
@@ -57,10 +51,7 @@
 #include <arpa/inet.h>
 #endif
 #include <sys/stat.h>
-
-#if USE_WIN32API
-#include <winsock2.h>
-#endif
+#include "gdb_socket.h"
 
 #if __QNX__
 #include <sys/iomgr.h>
@@ -153,14 +144,14 @@ enable_async_notification (int fd)
 static int
 handle_accept_event (int err, gdb_client_data client_data)
 {
-  struct sockaddr_in sockaddr;
+  union gdb_sockaddr_u sockaddr;
   socklen_t tmp;
 
   if (debug_threads)
     debug_printf ("handling possible accept event\n");
 
-  tmp = sizeof (sockaddr);
-  remote_desc = accept (listen_desc, (struct sockaddr *) &sockaddr, &tmp);
+  tmp = sizeof (sockaddr.sa_in);
+  remote_desc = accept (listen_desc, &sockaddr.sa, &tmp);
   if (remote_desc == -1)
     perror_with_name ("Accept failed");
 
@@ -195,7 +186,7 @@ handle_accept_event (int err, gdb_client_data client_data)
 
   /* Convert IP address to string.  */
   fprintf (stderr, "Remote debugging from host %s\n",
-	   inet_ntoa (sockaddr.sin_addr));
+	   inet_ntoa (sockaddr.sa_in.sin_addr));
 
   enable_async_notification (remote_desc);
 
@@ -224,7 +215,7 @@ remote_prepare (char *name)
   static int winsock_initialized;
 #endif
   int port;
-  struct sockaddr_in sockaddr;
+  union gdb_sockaddr_u sockaddr;
   socklen_t tmp;
   char *port_end;
 
@@ -269,11 +260,11 @@ remote_prepare (char *name)
   setsockopt (listen_desc, SOL_SOCKET, SO_REUSEADDR, (char *) &tmp,
 	      sizeof (tmp));
 
-  sockaddr.sin_family = PF_INET;
-  sockaddr.sin_port = htons (port);
-  sockaddr.sin_addr.s_addr = INADDR_ANY;
+  sockaddr.sa_in.sin_family = PF_INET;
+  sockaddr.sa_in.sin_port = htons (port);
+  sockaddr.sa_in.sin_addr.s_addr = INADDR_ANY;
 
-  if (bind (listen_desc, (struct sockaddr *) &sockaddr, sizeof (sockaddr))
+  if (bind (listen_desc, &sockaddr.sa, sizeof (sockaddr.sa_in))
       || listen (listen_desc, 1))
     perror_with_name ("Can't bind address");