[gdb/python] Handle !Py_IsInitialized () in gdbpy_initialize
I tried out making python initialization fail by passing an incorrect
PYTHONHOME, and got:
...
$ PYTHONHOME=foo gdb -q
Python path configuration:
PYTHONHOME = 'foo'
...
Python Exception <class 'ModuleNotFoundError'>: No module named 'encodings'
Python not initialized
$
...
The relevant part of the code is:
...
static void
gdbpy_initialize (const struct extension_language_defn *extlang)
{
if (!do_start_initialization () && PyErr_Occurred ())
gdbpy_print_stack ();
gdbpy_enter enter_py;
...
What happens is that:
- do_start_initialization returns false because Py_InitializeFromConfig fails,
leaving us in the !Py_IsInitialized () state
- PyErr_Occurred () returns true
- gdbpy_print_stack is called, which prints
"Python Exception <class 'ModuleNotFoundError'>: No module named 'encodings"
The problem is that in the Py_IsInitialized () == false state, very few
functions can be called, and PyErr_Occurred is not one of them [1], and
likewise functions in gdbpy_print_stack.
Fix this by:
- guarding the PyErr_Occurred / gdbpy_print_stack part with Py_IsInitialized ().
- handling the !Py_IsInitialized () case by printing the failure PyStatus
in do_start_initialization
This gets us instead:
...
$ PYTHONHOME=foo ./gdb.sh -q
Python path configuration:
PYTHONHOME = 'foo'
...
Python initialization failed: failed to get the Python codec of the filesystem encoding
Python not initialized
$
...
Tested on aarch64-linux.
Approved-By: Tom Tromey <tom@tromey.com>
[1] https://docs.python.org/3/c-api/init.html#before-python-initialization
diff --git a/gdb/python/python.c b/gdb/python/python.c
index 7489b53..820fb58 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -2375,7 +2375,14 @@ do_start_initialization ()
init_done:
PyConfig_Clear (&config);
if (PyStatus_Exception (status))
- return false;
+ {
+ if (PyStatus_IsError (status))
+ gdb_printf (_("Python initialization failed: %s\n"), status.err_msg);
+ else
+ gdb_printf (_("Python initialization failed with exit status: %d\n"),
+ status.exitcode);
+ return false;
+ }
#endif
#else
Py_Initialize ();
@@ -2720,7 +2727,7 @@ do_initialize (const struct extension_language_defn *extlang)
static void
gdbpy_initialize (const struct extension_language_defn *extlang)
{
- if (!do_start_initialization () && PyErr_Occurred ())
+ if (!do_start_initialization () && Py_IsInitialized () && PyErr_Occurred ())
gdbpy_print_stack ();
gdbpy_enter enter_py;
