2009-08-04 Thiago Jung Bauermann <thiago.bauermann@gmail.com>

gdb/
	* linux-tdep.c (check_is_pie_binary,
	_initialize_linux_tdep): New functions.

gdb/testsuite/
	* gdb.base/pie-support.exp: New file.
	* gdb.base/pie-support.c: New file.

3 files changed, 123 insertions, 0 deletions

diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c
index 37770f5..6634703 100644
--- a/gdb/linux-tdep.c
+++ b/gdb/linux-tdep.c
@@ -18,8 +18,12 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include "defs.h"
+#include "gdbcore.h"
 #include "gdbtypes.h"
 #include "linux-tdep.h"
+#include "observer.h"
+
+#include "elf-bfd.h"
 
 /* This function is suitable for architectures that don't
    extend/override the standard siginfo structure.  */
@@ -134,3 +138,30 @@ linux_get_siginfo_type (struct gdbarch *gdbarch)
 
   return siginfo_type;
 }
+
+/* Observer for the executable_changed event, to check whether the new
+   exec binary is a PIE (Position Independent Executable) specimen, which
+   is currently unsupported.  */
+
+static void
+check_is_pie_binary (void)
+{
+  Elf_Internal_Ehdr *elf_hdr;
+
+  if (!exec_bfd)
+    return;
+  else if (bfd_get_flavour (exec_bfd) != bfd_target_elf_flavour)
+    return;
+
+  if (elf_tdata (exec_bfd)->elf_header->e_type == ET_DYN)
+    warning (_("\
+The current binary is a PIE (Position Independent Executable), which\n\
+GDB does NOT currently support.  Most debugger features will fail if used\n\
+in this session.\n"));
+}
+
+void
+_initialize_linux_tdep (void)
+{
+  observer_attach_executable_changed (check_is_pie_binary);
+}
diff --git a/gdb/testsuite/gdb.base/pie-support.c b/gdb/testsuite/gdb.base/pie-support.c
new file mode 100644
index 0000000..63768b9
--- /dev/null
+++ b/gdb/testsuite/gdb.base/pie-support.c
@@ -0,0 +1,34 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2009 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   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 <stdio.h>
+
+void
+f1 (int a)
+{
+  printf ("a = %d\n", a);
+}
+
+int
+main (int argc, char *argv[])
+{
+  f1 (1);
+
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.base/pie-support.exp b/gdb/testsuite/gdb.base/pie-support.exp
new file mode 100644
index 0000000..a1affb35
--- /dev/null
+++ b/gdb/testsuite/gdb.base/pie-support.exp
@@ -0,0 +1,58 @@
+# Copyright 2009 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+set testfile pie-support
+set srcfile ${testfile}.c
+set objfile ${objdir}/${subdir}/${testfile}.o
+set binfile ${objdir}/${subdir}/${testfile}
+
+if  { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${objfile}" object {debug additional_flags=-fpie}] != "" } {
+    untested "Couldn't compile test PIE object file."
+    return -1
+}
+if  { [gdb_compile "${objfile}" "${binfile}" executable {debug additional_flags=-pie}] != "" } {
+    untested "Couldn't compile test PIE binary."
+    return -1
+}
+
+# Get things started.
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+
+if [is_remote host] {
+  set binfile [remote_download host $binfile]
+    if { $binfile == "" } {
+      untested "Couldn't download remote test binary."
+      return -1
+    }
+}
+
+# The file command used to kill the remote target.  For the benefit
+# of the testsuite, preserve this behavior.
+send_gdb "kill\n"
+gdb_expect 120 {
+    -re "Kill the program being debugged. .y or n. $" {
+	send_gdb "y\n"
+	verbose "\t\tKilling previous program being debugged"
+	exp_continue
+    }
+    -re "$gdb_prompt $" {
+	# OK.
+    }
+}
+
+gdb_test "file $binfile" "current binary is a PIE.*" "correctly detected PIE binary"