Some signal dodging stuff.

diff --git a/src/python.c b/src/python.c
index b67a795..86bad3d 100644 (file)
--- a/src/python.c
+++ b/src/python.c
@@ -1,6 +1,7 @@
 #include <Python.h>
 #include <structmember.h>
 
+#include <signal.h>
 #if HAVE_PTHREAD_H
 # include <pthread.h>
 #endif
@@ -729,20 +730,59 @@ static int cpy_shutdown(void) {
                else
                        Py_DECREF(ret);
        }
+       PyErr_Print();
        Py_Finalize();
        return 0;
 }
 
+static void cpy_int_handler(int sig) {
+       return;
+}
+
 static void *cpy_interactive(void *data) {
-       CPY_LOCK_THREADS
-               if (PyImport_ImportModule("readline") == NULL) {
-                       /* This interactive session will suck. */
-                       cpy_log_exception("interactive session init");
-               }
-               PyRun_InteractiveLoop(stdin, "<stdin>");
-       CPY_RELEASE_THREADS
+       sigset_t sigset;
+       struct sigaction sig_int_action, old;
+       
+       /* Signal handler in a plugin? Bad stuff, but the best way to
+        * handle it I guess. In an interactive session people will
+        * press Ctrl+C at some time, which will generate a SIGINT.
+        * This will cause collectd to shutdown, thus killing the
+        * interactive interpreter, and leaving the terminal in a
+        * mess. Chances are, this isn't what the user wanted to do.
+        * 
+        * So this is the plan:
+        * 1. Block SIGINT in the main thread.
+        * 2. Install our own signal handler that does nothing.
+        * 3. Unblock SIGINT in the interactive thread.
+        *
+        * This will make sure that SIGINT won't kill collectd but
+        * still interrupt syscalls like sleep and pause.
+        * It does not raise a KeyboardInterrupt exception because so
+        * far nobody managed to figure out how to do that. */
+       memset (&sig_int_action, '\0', sizeof (sig_int_action));
+       sig_int_action.sa_handler = cpy_int_handler;
+       sigaction (SIGINT, &sig_int_action, &old);
+       
+       sigemptyset(&sigset);
+       sigaddset(&sigset, SIGINT);
+       pthread_sigmask(SIG_UNBLOCK, &sigset, NULL);
+       PyEval_AcquireThread(state);
+       if (PyImport_ImportModule("readline") == NULL) {
+               /* This interactive session will suck. */
+               cpy_log_exception("interactive session init");
+       }
+       PyRun_InteractiveLoop(stdin, "<stdin>");
+       PyErr_Print();
+       PyEval_ReleaseThread(state);
        NOTICE("python: Interactive interpreter exited, stopping collectd ...");
+       /* Restore the original collectd SIGINT handler and raise SIGINT.
+        * The main thread still has SIGINT blocked and there's nothing we
+        * can do about that so this thread will handle it. But that's not
+        * important, except that it won't interrupt the main loop and so
+        * it might take a few seconds before collectd really shuts down. */
+       sigaction (SIGINT, &old, NULL);
        raise(SIGINT);
+       pause();
        return NULL;
 }
 
@@ -750,6 +790,7 @@ static int cpy_init(void) {
        cpy_callback_t *c;
        PyObject *ret;
        static pthread_t thread;
+       sigset_t sigset;
        
        PyEval_InitThreads();
        /* Now it's finally OK to use python threads. */
@@ -760,6 +801,9 @@ static int cpy_init(void) {
                else
                        Py_DECREF(ret);
        }
+       sigemptyset(&sigset);
+       sigaddset(&sigset, SIGINT);
+       pthread_sigmask(SIG_BLOCK, &sigset, NULL);
        state = PyEval_SaveThread();
        if (do_interactive) {
                if (pthread_create(&thread, NULL, cpy_interactive, NULL)) {