[PATCH] Unexpected EOF read from connection with GDB after inferior exits.

This is on GNU/Linux.

GDBserver does not exit properly when the inferior exits, as demonstrated
with any program using the procedure below:

   % gdbserver-head :4444 simple_main
   Process simple_main created; pid = 25681
   Listening on port 4444

Then, in another terminal, start GDB, connect to GDBserver, and run
the program to completion:

   % gdb-head simple_main
   (gdb) tar rem :4444
   (gdb) cont
   Continuing.

   Program exited normally.

Going back to the terminal where GDBserver is running, we see the following
output:

    Child exited with status 0
    readchar: Got EOF
    Remote side has terminated connection.  GDBserver will reopen the connection.
    Listening on port 4444

The problem is that we're missing a call to mourn_inferior.  As a result,
after we've handled the vCont packet, we fail to notice that there are
no process left to debug (target_running() returns true), and thus try
to continue reading from the remote socket.  However, since GDB just
disconnected after having received the "exit with status 0" reply to the
vCont request, the read triggers the EOF exception.

gdb/gdbserver/ChangeLog:

        * server.c (handle_v_cont): Call mourn_inferior if process
        just exited.
        (myresume): Likewise.

diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 531bc6c..8f50ce0 100644 (file)
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,9 @@
+2010-07-07  Joel Brobecker  <brobecker@adacore.com>
+
+       * server.c (handle_v_cont): Call mourn_inferior if process
+       just exited.
+       (myresume): Likewise.
+
 2010-07-01  Pedro Alves  <pedro@codesourcery.com>
 
        Static tracepoints, and integration with UST.

diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index 226d123..9125f0e 100644 (file)
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -1779,6 +1779,10 @@ handle_v_cont (char *own_buf)
       last_ptid = mywait (minus_one_ptid, &last_status, 0, 1);
       prepare_resume_reply (own_buf, last_ptid, &last_status);
       disable_async_io ();
+
+      if (last_status.kind == TARGET_WAITKIND_EXITED
+          || last_status.kind == TARGET_WAITKIND_SIGNALLED)
+        mourn_inferior (find_process_pid (ptid_get_pid (last_ptid)));
     }
   return;
 
@@ -2079,6 +2083,10 @@ myresume (char *own_buf, int step, int sig)
       last_ptid = mywait (minus_one_ptid, &last_status, 0, 1);
       prepare_resume_reply (own_buf, last_ptid, &last_status);
       disable_async_io ();
+
+      if (last_status.kind == TARGET_WAITKIND_EXITED
+          || last_status.kind == TARGET_WAITKIND_SIGNALLED)
+        mourn_inferior (find_process_pid (ptid_get_pid (last_ptid)));
     }
 }