tests: Add basic test coverage for GC'ing unused instance directories

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

tests/Makefile.am.inc

@@ -86,6 +86,14 @@ test_exports_CFLAGS = $(testcommon_CFLAGS)
 test_exports_LDADD = $(testcommon_LDADD) libtestlib.la
 test_exports_SOURCES = tests/test-exports.c
 
+test_instance_CFLAGS = $(testcommon_CFLAGS)
+test_instance_LDADD = $(testcommon_LDADD) libtestlib.la
+test_instance_SOURCES = tests/test-instance.c
+
+tests_hold_lock_CFLAGS = $(AM_CFLAGS) $(BASE_CFLAGS)
+tests_hold_lock_LDADD = $(AM_LDADD) $(BASE_LIBS) libglnx.la
+tests_hold_lock_SOURCES = tests/hold-lock.c
+
 tests_httpcache_CFLAGS = $(AM_CFLAGS) $(BASE_CFLAGS) $(OSTREE_CFLAGS) $(SOUP_CFLAGS) $(JSON_CFLAGS) $(APPSTREAM_GLIB_CFLAGS) \
 	-DFLATPAK_COMPILATION \
 	-DLOCALEDIR=\"$(localedir)\"
@@ -267,8 +275,21 @@ test_scripts = ${TEST_MATRIX}
 dist_test_scripts = ${TEST_MATRIX_DIST}
 dist_installed_test_extra_scripts += ${TEST_MATRIX_EXTRA_DIST}
 
-test_programs = testlibrary testcommon test-exports
-test_extra_programs = tests/httpcache tests/test-update-portal tests/test-portal-impl tests/test-authenticator tests/list-unused
+test_programs = \
+	test-exports \
+	test-instance \
+	testcommon \
+	testlibrary \
+	$(NULL)
+
+test_extra_programs = \
+	tests/hold-lock \
+	tests/httpcache \
+	tests/list-unused \
+	tests/test-authenticator \
+	tests/test-portal-impl \
+	tests/test-update-portal \
+	$(NULL)
 
 @VALGRIND_CHECK_RULES@
 VALGRIND_SUPPRESSIONS_FILES=tests/flatpak.supp tests/glib.supp

tests/hold-lock.c

@@ -0,0 +1,217 @@
+/*
+ * Copyright © 2019-2021 Collabora Ltd.
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <glib.h>
+#include <glib/gstdio.h>
+
+#include <fcntl.h>
+#include <fcntl.h>
+#include <sysexits.h>
+#include <sys/prctl.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "libglnx/libglnx.h"
+
+static GArray *global_locks = NULL;
+static gboolean opt_wait = FALSE;
+static gboolean opt_write = FALSE;
+
+static gboolean
+opt_fd_cb (const char *name,
+           const char *value,
+           gpointer data,
+           GError **error)
+{
+  char *endptr;
+  gint64 i64 = g_ascii_strtoll (value, &endptr, 10);
+  int fd;
+  int fd_flags;
+
+  g_return_val_if_fail (global_locks != NULL, FALSE);
+  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+  g_return_val_if_fail (value != NULL, FALSE);
+
+  if (i64 < 0 || i64 > G_MAXINT || endptr == value || *endptr != '\0')
+    {
+      g_set_error (error, G_OPTION_ERROR, G_OPTION_ERROR_BAD_VALUE,
+                   "Integer out of range or invalid: %s", value);
+      return FALSE;
+    }
+
+  fd = (int) i64;
+
+  fd_flags = fcntl (fd, F_GETFD);
+
+  if (fd_flags < 0)
+    return glnx_throw_errno_prefix (error, "Unable to receive --fd %d", fd);
+
+  if ((fd_flags & FD_CLOEXEC) == 0
+      && fcntl (fd, F_SETFD, fd_flags | FD_CLOEXEC) != 0)
+    return glnx_throw_errno_prefix (error,
+                                    "Unable to configure --fd %d for "
+                                    "close-on-exec",
+                                    fd);
+
+  g_array_append_val (global_locks, fd);
+  return TRUE;
+}
+
+static gboolean
+opt_lock_file_cb (const char *name,
+                  const char *value,
+                  gpointer data,
+                  GError **error)
+{
+  int open_flags = O_CLOEXEC | O_CREAT | O_NOCTTY | O_RDWR;
+  int fd;
+  int cmd;
+  struct flock l =
+  {
+    .l_type = F_RDLCK,
+    .l_whence = SEEK_SET,
+    .l_start = 0,
+    .l_len = 0,
+  };
+
+  g_return_val_if_fail (global_locks != NULL, FALSE);
+  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+  g_return_val_if_fail (value != NULL, FALSE);
+
+  fd = TEMP_FAILURE_RETRY (open (value, open_flags, 0644));
+
+  if (fd < 0)
+    return glnx_throw_errno_prefix (error, "open %s", value);
+
+  if (opt_write)
+    l.l_type = F_WRLCK;
+
+  if (opt_wait)
+    cmd = F_SETLKW;
+  else
+    cmd = F_SETLK;
+
+  if (TEMP_FAILURE_RETRY (fcntl (fd, cmd, &l)) < 0)
+    {
+      if (errno == EACCES || errno == EAGAIN)
+        g_set_error (error, G_IO_ERROR, G_IO_ERROR_BUSY,
+                     "Unable to lock %s: file is busy", value);
+      else
+        glnx_throw_errno_prefix (error, "lock %s", value);
+
+      close (fd);
+      return FALSE;
+    }
+
+  g_array_append_val (global_locks, fd);
+  return TRUE;
+}
+
+static GOptionEntry options[] =
+{
+  { "fd", '\0',
+    G_OPTION_FLAG_NONE, G_OPTION_ARG_CALLBACK, opt_fd_cb,
+    "Take a file descriptor, already locked if desired, and keep it "
+    "open. May be repeated.",
+    NULL },
+
+  { "wait", '\0',
+    G_OPTION_FLAG_NONE, G_OPTION_ARG_NONE, &opt_wait,
+    "Wait for each subsequent lock file.",
+    NULL },
+  { "no-wait", '\0',
+    G_OPTION_FLAG_REVERSE, G_OPTION_ARG_NONE, &opt_wait,
+    "Exit unsuccessfully if a lock-file is busy [default].",
+    NULL },
+
+  { "write", '\0',
+    G_OPTION_FLAG_NONE, G_OPTION_ARG_NONE, &opt_write,
+    "Lock each subsequent lock file for write access.",
+    NULL },
+  { "no-write", '\0',
+    G_OPTION_FLAG_REVERSE, G_OPTION_ARG_NONE, &opt_write,
+    "Lock each subsequent lock file for read-only access [default].",
+    NULL },
+
+  { "lock-file", '\0',
+    G_OPTION_FLAG_NONE, G_OPTION_ARG_CALLBACK, opt_lock_file_cb,
+    "Open the given file and lock it, affected by options appearing "
+    "earlier on the command-line. May be repeated.",
+    NULL },
+
+  { NULL }
+};
+
+int
+main (int argc,
+      char *argv[])
+{
+  g_autoptr(GArray) locks = NULL;
+  g_autoptr(GOptionContext) context = NULL;
+  g_autoptr(GError) local_error = NULL;
+  GError **error = &local_error;
+  int ret = EX_USAGE;
+
+  locks = g_array_new (FALSE, FALSE, sizeof (int));
+  global_locks = locks;
+
+  context = g_option_context_new (NULL);
+  g_option_context_add_main_entries (context, options, NULL);
+
+  if (!g_option_context_parse (context, &argc, &argv, error))
+    {
+      if (g_error_matches (local_error, G_IO_ERROR, G_IO_ERROR_BUSY))
+        ret = EX_TEMPFAIL;
+      else if (local_error->domain == G_OPTION_ERROR)
+        ret = EX_USAGE;
+      else
+        ret = EX_UNAVAILABLE;
+
+      goto out;
+    }
+
+  ret = EX_UNAVAILABLE;
+
+  /* Self-destruct when parent exits */
+  if (prctl (PR_SET_PDEATHSIG, SIGTERM, 0, 0, 0) != 0)
+    {
+      glnx_throw_errno_prefix (error,
+                               "Unable to set parent death signal");
+      goto out;
+    }
+
+  /* Signal to caller that we are ready */
+  fclose (stdout);
+
+  while (TRUE)
+    pause ();
+
+  g_assert_not_reached ();
+
+out:
+  global_locks = NULL;
+
+  if (local_error != NULL)
+    g_warning ("%s", local_error->message);
+
+  return ret;
+}

tests/test-instance.c

@@ -0,0 +1,125 @@
+/*
+ * Copyright © 2021 Collabora Ltd.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <utime.h>
+
+#include <glib.h>
+#include <glib/gstdio.h>
+
+#include "flatpak.h"
+#include "flatpak-instance-private.h"
+
+#include "libglnx/libglnx.h"
+
+#include "testlib.h"
+
+static void
+test_gc (void)
+{
+  g_autoptr(GBytes) bytes = NULL;
+  g_autoptr(GError) error = NULL;
+  g_autoptr(GPtrArray) instances = NULL;
+  g_autofree char *base_dir = flatpak_instance_get_instances_directory ();
+  g_autofree char *alive_dir = g_build_filename (base_dir, "1", NULL);
+  g_autofree char *alive_lock = g_build_filename (alive_dir, ".ref", NULL);
+  g_autofree char *dead_dir = g_build_filename (base_dir, "2", NULL);
+  g_autofree char *dead_lock = g_build_filename (dead_dir, ".ref", NULL);
+  g_autofree char *hold_lock = g_test_build_filename (G_TEST_BUILT, "hold-lock", NULL);
+  struct utimbuf a_while_ago = {};
+  const char *hold_lock_argv[] = { "hold-lock", "--lock-file", ".ref", NULL };
+  GPid pid = -1;
+  int stdout_fd = -1;
+  int wstatus = 0;
+  FlatpakInstance *instance;
+  struct stat stat_buf;
+
+  g_assert_no_errno (g_mkdir_with_parents (alive_dir, 0700));
+  g_assert_no_errno (g_mkdir_with_parents (dead_dir, 0700));
+  g_file_set_contents (alive_lock, "", 0, &error);
+  g_assert_no_error (error);
+  g_file_set_contents (dead_lock, "", 0, &error);
+  g_assert_no_error (error);
+
+  hold_lock_argv[0] = hold_lock;
+  hold_lock_argv[2] = alive_lock;
+  g_spawn_async_with_pipes (NULL,
+                            (gchar **) hold_lock_argv,
+                            NULL,
+                            G_SPAWN_DO_NOT_REAP_CHILD,
+                            NULL,
+                            NULL,
+                            &pid,
+                            NULL,
+                            &stdout_fd,
+                            NULL,
+                            &error);
+  g_assert_no_error (error);
+  g_assert_cmpint (pid, >, 1);
+  g_assert_cmpint (stdout_fd, >=, 0);
+
+  /* Wait for the child to be ready */
+  bytes = glnx_fd_readall_bytes (stdout_fd, NULL, &error);
+  g_assert_no_error (error);
+
+  /* Pretend the locks were created in early 1970, to bypass the workaround
+   * for a race */
+  g_assert_no_errno (g_utime (alive_lock, &a_while_ago));
+  g_assert_no_errno (g_utime (dead_lock, &a_while_ago));
+
+  /* This has the side-effect of GC'ing instances */
+  instances = flatpak_instance_get_all ();
+
+  g_assert_no_errno (stat (alive_dir, &stat_buf));
+  g_assert_cmpint (stat (dead_dir, &stat_buf) == 0 ? 0 : errno, ==, ENOENT);
+
+  g_assert_cmpuint (instances->len, ==, 1);
+  instance = g_ptr_array_index (instances, 0);
+  g_assert_true (FLATPAK_IS_INSTANCE (instance));
+  g_assert_cmpstr (flatpak_instance_get_id (instance), ==, "1");
+
+  kill (pid, SIGTERM);
+  g_assert_no_errno (waitpid (pid, &wstatus, 0));
+  g_assert_true (WIFSIGNALED (wstatus));
+  g_assert_cmpint (WTERMSIG (wstatus), ==, SIGTERM);
+  g_spawn_close_pid (pid);
+}
+
+int
+main (int argc, char *argv[])
+{
+  int res;
+
+  isolated_test_dir_global_setup ();
+
+  g_test_init (&argc, &argv, NULL);
+
+  g_test_add_func ("/instance/gc", test_gc);
+
+  res = g_test_run ();
+
+  isolated_test_dir_global_teardown ();
+
+  return res;
+}