plugins/python/pyhelpers: have a default sudo_printf function

Adapted the default sudo_printf from sudoers plugin to be able to print
errors before plugin open() gets called. (This is used by the multiple io
plugin loading to display error for too much plugin load.)

Since this makes us always have a sudo_log, I have removed the logic about
whether it is available or not.

plugins/python/pyhelpers.c

@@ -25,16 +25,45 @@
 
 #include <pwd.h>
 #include <signal.h>
+#include "pathnames.h"
 
-static int _sudo_printf_noop(int msg_type, const char *fmt, ...)
+static int
+_sudo_printf_default(int msg_type, const char *fmt, ...)
 {
-    (void) msg_type;
-    (void) fmt;
-    return 0;
+    FILE *fp = stdout;
+    FILE *ttyfp = NULL;
+    va_list ap;
+    int len;
+
+    if (ISSET(msg_type, SUDO_CONV_PREFER_TTY)) {
+	/* Try writing to /dev/tty first. */
+	ttyfp = fopen(_PATH_TTY, "w");
+    }
+
+    switch (msg_type & 0xff) {
+    case SUDO_CONV_ERROR_MSG:
+	fp = stderr;
+	/* FALLTHROUGH */
+    case SUDO_CONV_INFO_MSG:
+	va_start(ap, fmt);
+	len = vfprintf(ttyfp ? ttyfp : fp, fmt, ap);
+	va_end(ap);
+	break;
+    default:
+	len = -1;
+	errno = EINVAL;
+	break;
+    }
+
+    if (ttyfp != NULL)
+	fclose(ttyfp);
+
+    return len;
 }
 
+
 struct PythonContext py_ctx = {
-    &_sudo_printf_noop,
+    &_sudo_printf_default,
     NULL,
     0,
     NULL
@@ -45,7 +74,7 @@ int
 py_is_sudo_log_available(void)
 {
     debug_decl(py_is_sudo_log_available, PYTHON_DEBUG_INTERNAL);
-    debug_return_int(py_ctx.sudo_log != &_sudo_printf_noop);
+    debug_return_int(py_ctx.sudo_log != &_sudo_printf_default);
 }
 
 char *
@@ -408,7 +437,7 @@ void
 py_ctx_reset()
 {
     memset(&py_ctx, 0, sizeof(py_ctx));
-    py_ctx.sudo_log = &_sudo_printf_noop;
+    py_ctx.sudo_log = &_sudo_printf_default;
 }
 
 int

plugins/python/pyhelpers.h

@@ -59,8 +59,6 @@ int py_sudo_conv(int num_msgs, const struct sudo_conv_message msgs[],
 
 void py_log_last_error(const char *context_message);
 
-int py_is_sudo_log_available(void);
-
 char *py_create_string_rep(PyObject *py_object);
 
 char *py_join_str_list(PyObject *py_str_list, const char *separator);

plugins/python/python_plugin_common.c

@@ -194,7 +194,8 @@ python_plugin_register_logging(sudo_conv_t conversation,
     if (py_ctx.sudo_conv == NULL)
         py_ctx.sudo_conv = conversation;
 
-    py_ctx.sudo_log = sudo_printf;
+    if (sudo_printf)
+        py_ctx.sudo_log = sudo_printf;
 
     struct sudo_conf_debug_file_list debug_files = TAILQ_HEAD_INITIALIZER(debug_files);
     struct sudo_conf_debug_file_list *debug_files_ptr = &debug_files;

plugins/python/regress/check_python_examples.c

@@ -234,7 +234,6 @@ check_example_io_plugin_command_log_multiple(void)
         VERIFY_PTR_NE(python_io2, NULL);
         VERIFY_PTR_NE(python_io2, python_io);
     }
-    VERIFY_PTR((*python_io_clone)(), NULL);  // no more available
 
     // open the first plugin and let it log to tmp_dir
     create_io_plugin_options(data.tmp_dir);
@@ -250,6 +249,10 @@ check_example_io_plugin_command_log_multiple(void)
                               data.user_info, data.command_info, data.plugin_argc, data.plugin_argv,
                               data.user_env, data.plugin_options), SUDO_RC_OK);
 
+    // For verifying the error message of no more plugin. It should be displayed only once.
+    VERIFY_PTR((*python_io_clone)(), NULL);
+    VERIFY_PTR((*python_io_clone)(), NULL);
+
     // open the second plugin with another log directory
     VERIFY_TRUE(asprintf(&data.tmp_dir2, TEMP_PATH_TEMPLATE) >= 0);
     VERIFY_NOT_NULL(mkdtemp(data.tmp_dir2));

plugins/python/regress/testdata/check_example_io_plugin_command_log_multiple.stderr

@@ -0,0 +1 @@
+sudo: loading more than 8 sudo python IO plugins is not supported

plugins/python/sudo_python_module.c

@@ -113,11 +113,6 @@ python_sudo_log(int msg_type, PyObject *Py_UNUSED(py_self), PyObject *py_args, P
     if (_parse_log_function_args(py_args, py_kwargs, &args_joined, &end) != SUDO_RC_OK)
         goto cleanup;
 
-    if (!py_is_sudo_log_available()) {
-        PyErr_Format(sudo_exc_SudoException, "sudo.log: Message displaying is unavailable");
-        goto cleanup;
-    }
-
     rc = py_ctx.sudo_log(msg_type, "%s%s", args_joined, end);
     if (rc < 0) {
         PyErr_Format(sudo_exc_SudoException, "sudo.log: Error displaying message");