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/*
* Copyright (C) 2017 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include "locking.h"
#include "locking.c"
#include "../libsnap-confine-private/cleanup-funcs.h"
#include "../libsnap-confine-private/test-utils.h"
#include <errno.h>
#include <glib.h>
#include <glib/gstdio.h>
// Set alternate locking directory
static void sc_set_lock_dir(const char *dir) { sc_lock_dir = dir; }
// A variant of unsetenv that is compatible with GDestroyNotify
static void my_unsetenv(const char *k) { unsetenv(k); }
// Use temporary directory for locking.
//
// The directory is automatically reset to the real value at the end of the
// test.
static const char *sc_test_use_fake_lock_dir(void) {
char *lock_dir = NULL;
if (g_test_subprocess()) {
// Check if the environment variable is set. If so then someone is already
// managing the temporary directory and we should not create a new one.
lock_dir = getenv("SNAP_CONFINE_LOCK_DIR");
g_assert_nonnull(lock_dir);
} else {
lock_dir = g_dir_make_tmp(NULL, NULL);
g_assert_nonnull(lock_dir);
g_test_queue_free(lock_dir);
g_assert_cmpint(setenv("SNAP_CONFINE_LOCK_DIR", lock_dir, 0), ==, 0);
g_test_queue_destroy((GDestroyNotify)my_unsetenv, "SNAP_CONFINE_LOCK_DIR");
g_test_queue_destroy((GDestroyNotify)rm_rf_tmp, lock_dir);
}
g_test_queue_destroy((GDestroyNotify)sc_set_lock_dir, SC_LOCK_DIR);
sc_set_lock_dir(lock_dir);
return lock_dir;
}
// Check that locking a namespace actually flock's the mutex with LOCK_EX
static void test_sc_lock_unlock(void) {
if (geteuid() != 0) {
g_test_skip("this test only runs as root");
return;
}
const char *lock_dir = sc_test_use_fake_lock_dir();
int fd = sc_lock_generic("foo", 123);
// Construct the name of the lock file
char *lock_file SC_CLEANUP(sc_cleanup_string) = NULL;
lock_file = g_strdup_printf("%s/foo.123.lock", lock_dir);
// Open the lock file again to obtain a separate file descriptor.
// According to flock(2) locks are associated with an open file table entry
// so this descriptor will be separate and can compete for the same lock.
int lock_fd SC_CLEANUP(sc_cleanup_close) = -1;
lock_fd = open(lock_file, O_RDWR | O_CLOEXEC | O_NOFOLLOW);
g_assert_cmpint(lock_fd, !=, -1);
// The non-blocking lock operation should fail with EWOULDBLOCK as the lock
// file is locked by sc_nlock_ns_mutex() already.
int err = flock(lock_fd, LOCK_EX | LOCK_NB);
int saved_errno = errno;
g_assert_cmpint(err, ==, -1);
g_assert_cmpint(saved_errno, ==, EWOULDBLOCK);
// Unlock the lock.
sc_unlock(fd);
// Re-attempt the locking operation. This time it should succeed.
err = flock(lock_fd, LOCK_EX | LOCK_NB);
g_assert_cmpint(err, ==, 0);
}
// Check that holding a lock is properly detected.
static void test_sc_verify_snap_lock__locked(void) {
if (geteuid() != 0) {
g_test_skip("this test only runs as root");
return;
}
(void)sc_test_use_fake_lock_dir();
int fd = sc_lock_snap("foo");
sc_verify_snap_lock("foo");
sc_unlock(fd);
}
// Check that holding a lock is properly detected.
static void test_sc_verify_snap_lock__unlocked(void) {
if (geteuid() != 0) {
g_test_skip("this test only runs as root");
return;
}
(void)sc_test_use_fake_lock_dir();
if (g_test_subprocess()) {
sc_verify_snap_lock("foo");
return;
}
g_test_trap_subprocess(NULL, 0, 0);
g_test_trap_assert_failed();
g_test_trap_assert_stderr("unexpectedly managed to acquire exclusive lock over snap foo\n");
}
static void test_sc_enable_sanity_timeout(void) {
if (geteuid() != 0) {
g_test_skip("this test only runs as root");
return;
}
if (g_test_subprocess()) {
sc_enable_sanity_timeout();
debug("waiting...");
usleep(7 * G_USEC_PER_SEC);
debug("woke up");
sc_disable_sanity_timeout();
return;
}
g_test_trap_subprocess(NULL, 1 * G_USEC_PER_SEC, G_TEST_SUBPROCESS_INHERIT_STDERR);
g_test_trap_assert_failed();
g_test_trap_assert_stderr("sanity timeout expired: Interrupted system call\n");
}
// Set alternate inhibit directory
static void sc_set_inhibit_dir(const char *dir) { sc_inhibit_dir = dir; }
// Use temporary directory for inhibition.
//
// The directory is automatically reset to the real value at the end of the
// test.
static const char *sc_test_use_fake_inhibit_dir(void) {
char *inhibit_dir = g_dir_make_tmp(NULL, NULL);
g_assert_nonnull(inhibit_dir);
g_test_queue_free(inhibit_dir);
g_test_queue_destroy((GDestroyNotify)rm_rf_tmp, inhibit_dir);
g_test_queue_destroy((GDestroyNotify)sc_set_inhibit_dir, SC_INHIBIT_DIR);
sc_set_inhibit_dir(inhibit_dir);
return inhibit_dir;
}
static void test_sc_snap_is_inhibited__missing_dir(void) {
char *d = g_dir_make_tmp(NULL, NULL);
g_assert_nonnull(d);
g_test_queue_free(d);
g_test_queue_destroy((GDestroyNotify)rm_rf_tmp, d);
char subd[PATH_MAX];
sc_must_snprintf(subd, sizeof subd, "%s/absent", d);
sc_set_inhibit_dir(subd);
g_assert_false(sc_snap_is_inhibited("foo", SC_SNAP_HINT_INHIBITED_FOR_REMOVE));
}
static void test_sc_snap_is_inhibited__missing_file(void) {
sc_test_use_fake_inhibit_dir();
g_assert_false(sc_snap_is_inhibited("foo", SC_SNAP_HINT_INHIBITED_FOR_REMOVE));
}
static void test_sc_snap_is_inhibited__present_file(void) {
const char *d = sc_test_use_fake_inhibit_dir();
char pname[PATH_MAX];
sc_must_snprintf(pname, sizeof pname, "%s/foo.remove", d);
g_assert_true(g_file_set_contents(pname, "", -1, NULL));
g_assert_true(sc_snap_is_inhibited("foo", SC_SNAP_HINT_INHIBITED_FOR_REMOVE));
}
static void __attribute__((constructor)) init(void) {
g_test_add_func("/locking/sc_lock_unlock", test_sc_lock_unlock);
g_test_add_func("/locking/sc_enable_sanity_timeout", test_sc_enable_sanity_timeout);
g_test_add_func("/locking/sc_verify_snap_lock__locked", test_sc_verify_snap_lock__locked);
g_test_add_func("/locking/sc_verify_snap_lock__unlocked", test_sc_verify_snap_lock__unlocked);
g_test_add_func("/locking/sc_snap_is_inhibited__missing_dir", test_sc_snap_is_inhibited__missing_dir);
g_test_add_func("/locking/sc_snap_is_inhibited__missing_file", test_sc_snap_is_inhibited__missing_file);
g_test_add_func("/locking/sc_snap_is_inhibited__present_file", test_sc_snap_is_inhibited__present_file);
}
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