[PATCH] Allow gdb.lookup_objfile to work with symlinked binary

[Doug Evans <dje at google dot com>]

Hi.

This patch enhances gdb.lookup_objfile so that it works with a
symlinked binary.

Regression tested on amd64-linux.

2014-12-18  Doug Evans  <dje@google.com>

	* objfiles.c (objfile_filename): New function.
	* objfiles.h (objfile_filename): Declare it.
	(objfile_name): Add function comment.
	* python/py-objfile.c (objfpy_lookup_objfile_by_name): Try both the
	bfd file name (which may be realpath'd), and the original name.

	testsuite/
	* gdb.python/py-objfile.exp: Test gdb.lookup_objfile on symlinked
	binary.

diff --git a/gdb/objfiles.c b/gdb/objfiles.c
index 4dcd2e1..ceee634 100644
--- a/gdb/objfiles.c
+++ b/gdb/objfiles.c
@@ -1492,7 +1492,7 @@ default_iterate_over_objfiles_in_search_order
     }
 }
 
-/* Return canonical name for OBJFILE.  */
+/* See objfiles.h.  */
 
 const char *
 objfile_name (const struct objfile *objfile)
@@ -1506,6 +1506,17 @@ objfile_name (const struct objfile *objfile)
 /* See objfiles.h.  */
 
 const char *
+objfile_filename (const struct objfile *objfile)
+{
+  if (objfile->obfd != NULL)
+    return bfd_get_filename (objfile->obfd);
+
+  return NULL;
+}
+
+/* See objfiles.h.  */
+
+const char *
 objfile_debug_name (const struct objfile *objfile)
 {
   return lbasename (objfile->original_name);
diff --git a/gdb/objfiles.h b/gdb/objfiles.h
index 084af39..da2f62c 100644
--- a/gdb/objfiles.h
+++ b/gdb/objfiles.h
@@ -699,8 +699,17 @@ extern void default_iterate_over_objfiles_in_search_order
 
 void set_objfile_per_bfd (struct objfile *obj);
 
+/* Return canonical name for OBJFILE.
+   This is the real file name if the file has been opened.
+   Otherwise it is the original name supplied by the user.  */
+
 const char *objfile_name (const struct objfile *objfile);
 
+/* Return the (real) file name of OBJFILE if the file has been opened,
+   otherwise return NULL.  */
+
+const char *objfile_filename (const struct objfile *objfile);
+
 /* Return the name to print for OBJFILE in debugging messages.  */
 
 extern const char *objfile_debug_name (const struct objfile *objfile);
diff --git a/gdb/python/py-objfile.c b/gdb/python/py-objfile.c
index e78ceba..36eff35 100644
--- a/gdb/python/py-objfile.c
+++ b/gdb/python/py-objfile.c
@@ -438,12 +438,18 @@ objfpy_lookup_objfile_by_name (const char *name)
 
   ALL_OBJFILES (objfile)
     {
+      const char *filename;
+
       if ((objfile->flags & OBJF_NOT_FILENAME) != 0)
 	continue;
       /* Don't return separate debug files.  */
       if (objfile->separate_debug_objfile_backlink != NULL)
 	continue;
-      if (compare_filenames_for_search (objfile_name (objfile), name))
+
+      filename = objfile_filename (objfile);
+      if (filename != NULL && compare_filenames_for_search (filename, name))
+	return objfile;
+      if (compare_filenames_for_search (objfile->original_name, name))
 	return objfile;
     }
 
diff --git a/gdb/testsuite/gdb.python/py-objfile.exp b/gdb/testsuite/gdb.python/py-objfile.exp
index 5d3c084..0a2004f 100644
--- a/gdb/testsuite/gdb.python/py-objfile.exp
+++ b/gdb/testsuite/gdb.python/py-objfile.exp
@@ -115,3 +115,14 @@ if { [get_python_valueof "sep_objfile.build_id" "None"] != "None" } {
     gdb_test "python print (gdb.lookup_objfile (sep_objfile.build_id, by_build_id=True))" \
 	"Objfile not found\\.\r\n${python_error_text}"
 }
+
+# An objfile that was a symlink to a differently named file is still
+# findable with its original name.
+set symlink_binary [standard_output_file "symlink-binary"]
+remote_exec host "rm -f ${symlink_binary}"
+remote_exec host "ln -sf ${testfile} ${symlink_binary}"
+if [remote_file host exists "${symlink_binary}"] {
+    clean_restart "${symlink_binary}"
+    gdb_test "python print (gdb.lookup_objfile (\"${symlink_binary}\").filename)" \
+	"${testfile}" "gdb.lookup_objfile of symlinked binary"
+}