tests: Add a unit test for _dbus_command_for_pid()

In particular this demonstrates that dbus#222 has been solved.

Signed-off-by: Simon McVittie <smcv@collabora.com>

cmake/test/CMakeLists.txt

@@ -108,6 +108,7 @@ if(DBUS_WITH_GLIB)
     add_test_executable(test-relay ${TEST_DIR}/relay.c ${TEST_LIBRARIES})
     add_test_executable(test-server-oom ${TEST_DIR}/internals/server-oom.c ${TEST_LIBRARIES})
     add_test_executable(test-syntax ${TEST_DIR}/syntax.c ${TEST_LIBRARIES})
+    add_test_executable(test-sysdeps ${TEST_DIR}/internals/sysdeps.c ${TEST_LIBRARIES})
     add_test_executable(test-syslog ${TEST_DIR}/internals/syslog.c ${TEST_LIBRARIES})
     add_test_executable(test-uid-permissions ${TEST_DIR}/uid-permissions.c ${TEST_LIBRARIES})
     add_helper_executable(manual-authz ${TEST_DIR}/manual-authz.c ${TEST_LIBRARIES})

test/Makefile.am

@@ -108,6 +108,9 @@ test_refs_LDADD = libdbus-testutils.la $(GLIB_LIBS)
 test_server_oom_SOURCES = internals/server-oom.c
 test_server_oom_LDADD = libdbus-testutils.la $(GLIB_LIBS)
 
+test_sysdeps_SOURCES = internals/sysdeps.c
+test_sysdeps_LDADD =  libdbus-testutils.la $(GLIB_LIBS)
+
 test_syslog_SOURCES = internals/syslog.c
 test_syslog_LDADD = libdbus-testutils.la $(GLIB_LIBS)
 
@@ -172,6 +175,7 @@ installable_tests += \
 	test-relay \
 	test-server-oom \
 	test-syntax \
+	test-sysdeps \
 	test-syslog \
 	test-uid-permissions \
 	test-variant \

test/internals/sysdeps.c

@@ -0,0 +1,166 @@
+/*
+ * Copyright © 2018 Collabora Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <config.h>
+
+#include <dbus/dbus.h>
+#include "dbus/dbus-sysdeps.h"
+#include "test-utils-glib.h"
+
+typedef struct
+{
+  int dummy;
+} Fixture;
+
+static void
+setup (Fixture *f G_GNUC_UNUSED,
+       gconstpointer context G_GNUC_UNUSED)
+{
+}
+
+/* In an unfortunate clash of terminology, GPid is actually a process
+ * handle (a HANDLE, vaguely analogous to a file descriptor) on Windows.
+ * For _dbus_command_for_pid() we need an actual process ID. */
+#ifdef G_OS_UNIX
+# define NO_PROCESS 0
+# define terminate(process) kill (process, SIGTERM)
+# define get_pid(process) process
+#else
+# define NO_PROCESS NULL
+# define terminate(process) TerminateProcess (process, 1)
+# define get_pid(process) GetProcessId (process)
+#endif
+
+static void
+test_command_for_pid (Fixture *f,
+                      gconstpointer context G_GNUC_UNUSED)
+{
+  gchar *argv[] = { NULL, NULL, NULL };
+  GError *error = NULL;
+  GPid process = NO_PROCESS;
+  unsigned long pid;
+  DBusString string;
+
+  argv[0] = test_get_helper_executable ("test-sleep-forever" DBUS_EXEEXT);
+
+  if (argv[0] == NULL)
+    {
+      g_test_skip ("DBUS_TEST_EXEC not set");
+      return;
+    }
+
+  argv[1] = g_strdup ("bees");
+
+  if (!g_spawn_async (NULL, argv, NULL, G_SPAWN_DEFAULT, NULL, NULL,
+                      &process, &error))
+    g_error ("Unable to run %s: %s", argv[0], error->message);
+
+  pid = get_pid (process);
+
+  if (!_dbus_string_init (&string))
+    g_error ("out of memory");
+
+  if (_dbus_command_for_pid (pid, &string, strlen (argv[0]) + 1024, NULL))
+    {
+      gchar *expected;
+      int len;
+
+      g_test_message ("Process %lu: \"%s\"", pid,
+                      _dbus_string_get_const_data (&string));
+
+      len = _dbus_string_get_length (&string);
+      /* TODO: _dbus_command_for_pid() currently appends an unwanted
+       * space. See dbus#222 */
+      _dbus_string_chop_white (&string);
+
+      if (_dbus_string_get_length (&string) < len)
+        test_incomplete ("Ignoring unwanted whitespace");
+
+      expected = g_strdup_printf ("%s %s", argv[0], argv[1]);
+
+      g_assert_cmpstr (_dbus_string_get_const_data (&string), ==,
+                       expected);
+      g_assert_cmpuint (_dbus_string_get_length (&string), ==,
+                        strlen (expected));
+      g_free (expected);
+    }
+  else
+    {
+      g_test_message ("Unable to get command for process ID");
+    }
+
+  if (!_dbus_string_set_length (&string, 0))
+    g_error ("out of memory");
+
+  /* Test truncation */
+  if (_dbus_command_for_pid (pid, &string, 10, NULL))
+    {
+      gchar *expected;
+
+      g_test_message ("Process %lu (truncated): \"%s\"", pid,
+                      _dbus_string_get_const_data (&string));
+
+      expected = g_strdup_printf ("%s %s", argv[0], argv[1]);
+      expected[10] = '\0';
+
+      g_assert_cmpstr (_dbus_string_get_const_data (&string), ==,
+                       expected);
+      g_assert_cmpuint (_dbus_string_get_length (&string), ==, 10);
+      g_free (expected);
+    }
+  else
+    {
+      g_test_message ("Unable to get command for process ID");
+    }
+
+  if (process != NO_PROCESS)
+    terminate (process);
+
+  _dbus_string_free (&string);
+  g_spawn_close_pid (process);
+  g_free (argv[1]);
+  g_free (argv[0]);
+}
+
+static void
+teardown (Fixture *f G_GNUC_UNUSED,
+          gconstpointer context G_GNUC_UNUSED)
+{
+}
+
+int
+main (int argc,
+      char **argv)
+{
+  int ret;
+
+  test_init (&argc, &argv);
+
+  g_test_add ("/sysdeps/command_for_pid",
+              Fixture, NULL, setup, test_command_for_pid, teardown);
+
+  ret = g_test_run ();
+  dbus_shutdown ();
+  return ret;
+}