crashpad/util/mac/service_management_test.mm
Mark Mentovai 7669b33010 ServiceManagement test: reduce test flake.
ExpectProcessIsRunning() goes to a lot of trouble to deal with the flaky
{CTL_KERN, KERN_PROCARGS2} API exposed by ProcessArgumentsForPID(). It
retries that call inside an inner loop until it succeeds, because it may
fail while a process is mid-exec(). Once it succeeds, it should use the
argv it obtained. Waiting for success and then attempting to call
ProcessArgumentsForPID() again to get argv can be flaky when the first
attempt succeeds because it’s pre-exec(), and the second one catches the
process in the middle of the exec() and fails.

The existence of the inner loop was intended to protect against this
problem, and the subsequent call outside of the inner loop appears to be
left behind from before the inner loop existed. It should have been
removed when the inner loop was added.

TEST=util_test ServiceManagement.SubmitRemoveJob
R=rsesek@chromium.org

Review URL: https://codereview.chromium.org/644473005
2014-10-09 17:26:50 -04:00

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// Copyright 2014 The Crashpad Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "util/mac/service_management.h"
#import <Foundation/Foundation.h>
#include <launch.h>
#include <string>
#include <vector>
#include "base/mac/foundation_util.h"
#include "base/mac/scoped_cftyperef.h"
#include "base/strings/stringprintf.h"
#include "base/strings/sys_string_conversions.h"
#include "base/rand_util.h"
#include "gtest/gtest.h"
#include "util/misc/clock.h"
#include "util/posix/process_util.h"
#include "util/stdlib/objc.h"
namespace crashpad {
namespace test {
namespace {
// Ensures that the process with the specified PID is running, identifying it by
// requiring that its argv[argc - 1] compare equal to last_arg.
void ExpectProcessIsRunning(pid_t pid, std::string& last_arg) {
// The process may not have called exec yet, so loop with a small delay while
// looking for the cookie.
int outer_tries = 10;
std::vector<std::string> job_argv;
while (outer_tries--) {
// If the process is in the middle of calling exec, ProcessArgumentsForPID
// may fail. Loop with a small retry delay while waiting for the expected
// successful call.
int inner_tries = 10;
bool success;
do {
success = ProcessArgumentsForPID(pid, &job_argv);
if (success) {
break;
}
if (inner_tries > 0) {
SleepNanoseconds(1E6); // 1 millisecond
}
} while (inner_tries--);
ASSERT_TRUE(success);
ASSERT_FALSE(job_argv.empty());
if (job_argv.back() == last_arg) {
break;
}
if (outer_tries > 0) {
SleepNanoseconds(1E6); // 1 millisecond
}
}
ASSERT_FALSE(job_argv.empty());
EXPECT_EQ(last_arg, job_argv.back());
}
// Ensures that the process with the specified PID is not running. Because the
// PID may be reused for another process, a process is only treated as running
// if its argv[argc - 1] compares equal to last_arg.
void ExpectProcessIsNotRunning(pid_t pid, std::string& last_arg) {
// The process may not have exited yet, so loop with a small delay while
// checking that it has exited.
int tries = 10;
std::vector<std::string> job_argv;
while (tries--) {
if (!ProcessArgumentsForPID(pid, &job_argv)) {
// The PID was not found.
return;
}
// The PID was found. It may have been recycled for another process. Make
// sure that the cookie isnt found.
ASSERT_FALSE(job_argv.empty());
if (job_argv.back() != last_arg) {
break;
}
if (tries > 0) {
SleepNanoseconds(1E6); // 1 millisecond
}
}
ASSERT_FALSE(job_argv.empty());
EXPECT_NE(last_arg, job_argv.back());
}
TEST(ServiceManagement, SubmitRemoveJob) {
@autoreleasepool {
std::string cookie;
for (int index = 0; index < 16; ++index) {
cookie.append(1, base::RandInt('A', 'Z'));
}
std::string shell_script =
base::StringPrintf("sleep 10; echo %s", cookie.c_str());
NSString* shell_script_ns = base::SysUTF8ToNSString(shell_script);
const char kJobLabel[] = "com.googlecode.crashpad.test.service_management";
NSDictionary* job_dictionary_ns = @{
@LAUNCH_JOBKEY_LABEL : @"com.googlecode.crashpad.test.service_management",
@LAUNCH_JOBKEY_RUNATLOAD : @YES,
@LAUNCH_JOBKEY_PROGRAMARGUMENTS :
@[ @"/bin/sh", @"-c", shell_script_ns, ],
};
CFDictionaryRef job_dictionary_cf =
base::mac::NSToCFCast(job_dictionary_ns);
// The job may be left over from a failed previous run.
if (ServiceManagementIsJobLoaded(kJobLabel)) {
EXPECT_TRUE(ServiceManagementRemoveJob(kJobLabel, true));
}
EXPECT_FALSE(ServiceManagementIsJobLoaded(kJobLabel));
ASSERT_FALSE(ServiceManagementIsJobRunning(kJobLabel));
// Submit the job.
ASSERT_TRUE(ServiceManagementSubmitJob(job_dictionary_cf));
EXPECT_TRUE(ServiceManagementIsJobLoaded(kJobLabel));
// launchd started the job because RunAtLoad is true.
pid_t job_pid = ServiceManagementIsJobRunning(kJobLabel);
ASSERT_GT(job_pid, 0);
ExpectProcessIsRunning(job_pid, shell_script);
// Remove the job.
ASSERT_TRUE(ServiceManagementRemoveJob(kJobLabel, true));
EXPECT_FALSE(ServiceManagementIsJobLoaded(kJobLabel));
EXPECT_EQ(0, ServiceManagementIsJobRunning(kJobLabel));
// Now that the job is unloaded, a subsequent attempt to unload it should be
// an error.
EXPECT_FALSE(ServiceManagementRemoveJob(kJobLabel, false));
ExpectProcessIsNotRunning(job_pid, shell_script);
}
}
} // namespace
} // namespace test
} // namespace crashpad