Get GDBserver pid on remote target

Hi,
We see the following fail in the real remote testing...

(gdb) Executing on target: kill -9 29808    (timeout = 300)
spawn [open ...]^M
sh: 1: kill: No such process

The test tries to kill gdbserver in this way:

set server_pid [exp_pid -i [board_info target fileid]]
remote_exec target "kill -9 $server_pid"

in native testing, we'll get the pid of spawned gdbserver, however, in
remote testing, we'll get the pid of ssh session, since we start
gdbserver on the remote target through ssh.  The pid on build doesn't
exist on target.

In this patch, we tweak server-kill.c to get the parent pid, which is
the pid of GDBserver.  GDB gets it and kill GDBserver on target.

gdb/testsuite:

2014-10-11  Yao Qi  <yao@codesourcery.com>

	* gdb.server/server-kill.c: Include sys/types.h and unistd.h.
	(main): Call getppid.
	* gdb.server/server-kill.exp: Set breakpoint on line "i = 0;"
	and continue to it.  Read variable "server_pid".

2 files changed, 26 insertions, 2 deletions

diff --git a/gdb/testsuite/gdb.server/server-kill.c b/gdb/testsuite/gdb.server/server-kill.c
index 8a7c74e..8369024 100644
--- a/gdb/testsuite/gdb.server/server-kill.c
+++ b/gdb/testsuite/gdb.server/server-kill.c
@@ -15,10 +15,18 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
+#include <sys/types.h>
+#include <unistd.h>
+
+int server_pid;
+
 int
 main (void)
 {
-  int i = 0;
+  int i;
+
+  server_pid = getppid ();
+  i = 0;
 
   return i;
 }
diff --git a/gdb/testsuite/gdb.server/server-kill.exp b/gdb/testsuite/gdb.server/server-kill.exp
index b23c2b5..83c11f2 100644
--- a/gdb/testsuite/gdb.server/server-kill.exp
+++ b/gdb/testsuite/gdb.server/server-kill.exp
@@ -33,7 +33,23 @@ gdb_test "disconnect" ".*"
 
 gdbserver_run ""
 
-set server_pid [exp_pid -i [board_info target fileid]]
+# Continue past server_pid assignment.
+gdb_breakpoint ${srcfile}:[gdb_get_line_number "i = 0;"]
+gdb_continue_to_breakpoint "after server_pid assignment"
+
+# Get the pid of GDBServer.
+set test "p server_pid"
+gdb_test_multiple $test $test {
+    -re " = ($decimal)\r\n$gdb_prompt $" {
+	set server_pid $expect_out(1,string)
+	pass $test
+    }
+}
+
+if {$server_pid == "" } {
+    return -1
+}
+
 remote_exec target "kill -9 $server_pid"
 
 # Force GDB to talk with GDBserver, so that we can get the