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/*
* Phusion Passenger - https://www.phusionpassenger.com/
* Copyright (c) 2010-2018 Phusion Holding B.V.
*
* "Passenger", "Phusion Passenger" and "Union Station" are registered
* trademarks of Phusion Holding B.V.
*
* 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.
*/
#ifndef _PASSENGER_WATCHDOG_LAUNCHER_HPsg
#define _PASSENGER_WATCHDOG_LAUNCHER_HPsg
#include <sys/types.h>
#include <unistd.h>
#include "JsonTools/CBindings.h"
#ifdef __cplusplus
extern "C" {
#endif
typedef enum {
IM_APACHE,
IM_NGINX,
IM_STANDALONE
} PsgIntegrationMode;
typedef void PsgWatchdogLauncher;
typedef void (*PsgAfterForkCallback)(void *, void *);
PsgWatchdogLauncher *psg_watchdog_launcher_new(PsgIntegrationMode mode,
char **error_message);
int psg_watchdog_launcher_start(PsgWatchdogLauncher *launcher,
const char *passengerRoot,
PsgJsonValue *config,
const PsgAfterForkCallback afterFork,
void *callbackArgument,
char **errorMessage);
const char *psg_watchdog_launcher_get_core_address(PsgWatchdogLauncher *launcher, unsigned int *size);
const char *psg_watchdog_launcher_get_core_password(PsgWatchdogLauncher *launcher, unsigned int *size);
const char *psg_watchdog_launcher_get_instance_dir(PsgWatchdogLauncher *launcher, unsigned int *size);
pid_t psg_watchdog_launcher_get_pid(PsgWatchdogLauncher *launcher);
void psg_watchdog_launcher_detach(PsgWatchdogLauncher *launcher);
void psg_watchdog_launcher_free(PsgWatchdogLauncher *launcher);
#ifdef __cplusplus
} /* extern "C" */
#endif
#ifdef __cplusplus
#include <boost/function.hpp>
#include <oxt/system_calls.hpp>
#include <oxt/backtrace.hpp>
#include <string>
#include <vector>
#include <set>
#include <signal.h>
#include <jsoncpp/json.h>
#include <Constants.h>
#include <FileDescriptor.h>
#include <Exceptions.h>
#include <ResourceLocator.h>
#include <LoggingKit/LoggingKit.h>
#include <LoggingKit/Context.h>
#include <ProcessManagement/Utils.h>
#include <Utils.h>
#include <IOTools/IOUtils.h>
#include <IOTools/MessageIO.h>
#include <Utils/Timer.h>
#include <Utils/ScopeGuard.h>
#include <Utils/ClassUtils.h>
namespace Passenger {
using namespace std;
using namespace boost;
using namespace oxt;
/**
* Utility class for starting various the Passenger watchdog.
*/
class WatchdogLauncher {
/**
* Whether the starter process is Apache, Nginx or
* Passenger Standalone.
*/
P_RO_PROPERTY(private, PsgIntegrationMode, IntegrationMode);
/**
* The watchdog's PID. Equals 0 if the watchdog hasn't been started yet
* or if `detach()` is called.
*/
P_RO_PROPERTY(private, pid_t, Pid);
// Note: the use of `CONST_REF` in the properties below is intentional.
// The C getter functions return the string pointer directly.
/**
* The address on which the Passenger core listens for HTTP requests,
* and the corresponding password.
*
* Only valid when `getPid() != 0`.
*/
P_RO_PROPERTY_CONST_REF(private, string, CoreAddress);
P_RO_PROPERTY_CONST_REF(private, string, CorePassword);
/**
* The path to the instance directory that the Watchdog has created.
*
* Only valid when `getPid() != 0`.
*/
P_RO_PROPERTY_CONST_REF(private, string, InstanceDir);
private:
/** The watchdog's feedback file descriptor. */
FileDescriptor feedbackFd;
/**
* Safely dup2() the given file descriptor to 3 (FEEDBACK_FD).
*/
void installFeedbackFd(const FileDescriptor &fd) {
if (fd != FEEDBACK_FD && syscalls::dup2(fd, FEEDBACK_FD) == -1) {
int e = errno;
try {
writeArrayMessage(fd,
"system error",
"dup2() failed",
toString(e).c_str(),
NULL);
_exit(1);
} catch (...) {
fprintf(stderr,
"Passenger WatchdogLauncher: dup2() failed: %s (%d)\n",
strerror(e), e);
fflush(stderr);
_exit(1);
}
}
}
/**
* Call this if the watchdog seems to have crashed. This function will try
* to determine whether the watchdog is still running, whether it crashed
* with a signal, etc. If it has detected that the watchdog is no longer running
* then it will set `pid` to -1.
*/
void inspectWatchdogCrashReason(pid_t &pid) {
boost::this_thread::disable_interruption di;
boost::this_thread::disable_syscall_interruption dsi;
int ret, status;
/* Upon noticing that something went wrong, the watchdog
* or its subprocesses might still be writing out an error
* report, so we wait a while before killing the watchdog.
*/
ret = timedWaitPid(pid, &status, 5000);
if (ret == 0) {
/* Looks like the watchdog didn't crash and is still running. */
throw RuntimeException(
"Unable to start the " PROGRAM_NAME " watchdog: "
"it froze during startup and reported an unknown error");
} else if (ret != -1 && WIFSIGNALED(status)) {
/* Looks like a crash which caused a signal. */
pid = -1;
throw RuntimeException(
"Unable to start the " PROGRAM_NAME " watchdog: "
"it seems to have been killed with signal " +
getSignalName(WTERMSIG(status)) + " during startup");
} else if (ret == -1) {
/* Looks like it exited for a different reason and has no exit code. */
pid = -1;
throw RuntimeException(
"Unable to start the " PROGRAM_NAME " watchdog: "
"it seems to have crashed during startup for an unknown reason");
} else {
/* Looks like it exited for a different reason, but has an exit code. */
pid = -1;
throw RuntimeException(
"Unable to start the " PROGRAM_NAME " watchdog: "
"it seems to have crashed during startup for an unknown reason, "
"with exit code " + toString(WEXITSTATUS(status)));
}
}
void throwEnrichedWatchdogFailReason(const ResourceLocator &locator, const string &simpleReason) {
if (mIntegrationMode == IM_STANDALONE) {
throw RuntimeException("Unable to start " PROGRAM_NAME ": " + simpleReason +
". This probably means that your " SHORT_PROGRAM_NAME
" installation is broken or incomplete. Please try reinstalling " SHORT_PROGRAM_NAME);
} else {
string passengerRootConfig;
string docURL;
if (mIntegrationMode == IM_APACHE) {
passengerRootConfig = "PassengerRoot";
docURL = "https://www.phusionpassenger.com/library/config/apache/reference/#passengerroot";
} else {
passengerRootConfig = "passenger_root";
docURL = "https://www.phusionpassenger.com/library/config/nginx/reference/#passenger_root";
}
string message = "Unable to start " PROGRAM_NAME ": " + simpleReason +
". There may be different causes for this:\n\n"
" - Your '" + passengerRootConfig + "' setting is set to the wrong value."
" Please see " + docURL + " to learn how to fix the value.\n";
if (!locator.getBuildSystemDir().empty()) {
message.append(" - The " AGENT_EXE " binary is not compiled."
" Please run this command to compile it: "
+ locator.getBinDir() + "/passenger-config compile-agent\n");
}
message.append(" - Your " SHORT_PROGRAM_NAME " installation is broken or incomplete."
" Please reinstall " SHORT_PROGRAM_NAME ".");
throw RuntimeException(message);
}
}
static void killProcessGroupAndWait(pid_t *pid, unsigned long long timeout = 0) {
if (*pid != -1 && (timeout == 0 || timedWaitPid(*pid, NULL, timeout) <= 0)) {
boost::this_thread::disable_syscall_interruption dsi;
syscalls::killpg(*pid, SIGKILL);
syscalls::waitpid(*pid, NULL, 0);
*pid = -1;
}
}
/**
* Behaves like `waitpid(pid, status, WNOHANG)`, but waits at most
* `timeout` miliseconds for the process to exit.
*/
static int timedWaitPid(pid_t pid, int *status, unsigned long long timeout) {
Timer<SystemTime::GRAN_10MSEC> timer;
int ret;
do {
ret = syscalls::waitpid(pid, status, WNOHANG);
if (ret > 0 || ret == -1) {
return ret;
} else {
syscalls::usleep(10000);
}
} while (timer.elapsed() < timeout);
return 0; // timed out
}
public:
/**
* Construct a WatchdogLauncher object. The watchdog won't be started
* until you call `start()`.
*/
WatchdogLauncher(PsgIntegrationMode _integrationMode)
: mIntegrationMode(_integrationMode),
mPid(0)
{ }
~WatchdogLauncher() {
if (mPid != 0) {
boost::this_thread::disable_syscall_interruption dsi;
/* Send a message down the feedback fd to tell the watchdog
* that we're shutting down cleanly. Closing the fd without
* sending anything indicates an unclean shutdown.
*/
syscalls::write(feedbackFd, "c", 1);
feedbackFd.close();
syscalls::waitpid(mPid, NULL, 0);
}
}
const char *getIntegrationModeString() const {
switch (mIntegrationMode) {
case IM_APACHE:
return "apache";
case IM_NGINX:
return "nginx";
case IM_STANDALONE:
return "standalone";
default:
return "unknown";
}
}
/**
* Start the agents through the watchdog.
*
* @throws SystemException Something went wrong.
* @throws IOException Something went wrong while communicating with one
* of the agents during its initialization phase.
* @throws RuntimeException Something went wrong.
*/
void start(const string &passengerRoot,
const Json::Value &extraConfig = Json::Value(),
const boost::function<void ()> &afterFork = boost::function<void ()>())
{
TRACE_POINT();
boost::this_thread::disable_interruption di;
boost::this_thread::disable_syscall_interruption dsi;
ResourceLocator locator(passengerRoot);
string agentFilename;
try {
agentFilename = locator.findSupportBinary(AGENT_EXE);
} catch (const Passenger::RuntimeException &e) {
throwEnrichedWatchdogFailReason(locator, e.what());
}
SocketPair fds;
int e;
pid_t pid;
Json::Value::const_iterator it;
Json::Value config;
config["web_server_control_process_pid"] = getpid();
config["integration_mode"] = getIntegrationModeString();
config["passenger_root"] = passengerRoot;
config["log_level"] = (int) LoggingKit::getLevel();
for (it = extraConfig.begin(); it != extraConfig.end(); it++) {
config[it.name()] = *it;
}
fds = createUnixSocketPair(__FILE__, __LINE__);
pid = syscalls::fork();
if (pid == 0) {
// Child
/* Become the session leader so that Apache can't kill the
* watchdog with killpg() during shutdown, so that a
* Ctrl-C only affects the web server, and so that
* we can kill all of our subprocesses in a single killpg().
*/
setsid();
/* We don't know how the web server or the environment affect
* signal handlers and the signal mask, so reset this stuff
* just in case. Also, we reset the signal handlers before
* closing all file descriptors, in order to prevent bugs
* like this: https://github.com/phusion/passenger/pull/97
*/
resetSignalHandlersAndMask();
// Make sure the feedback fd is 3 and close all file descriptors
// except stdin, stdout, stderr and 3.
close(fds[0]);
installFeedbackFd(fds[1]);
setenv("PASSENGER_USE_FEEDBACK_FD", "true", 1);
if (afterFork) {
afterFork();
}
closeAllFileDescriptors(FEEDBACK_FD);
execl(agentFilename.c_str(), AGENT_EXE, "watchdog",
// Some extra space to allow the child process to change its process title.
" ",
(char *) 0);
e = errno;
try {
writeArrayMessage(FEEDBACK_FD,
"exec error",
toString(e).c_str(),
NULL);
_exit(1);
} catch (...) {
fprintf(stderr, "Passenger WatchdogLauncher: could not execute %s: %s (%d)\n",
agentFilename.c_str(), strerror(e), e);
fflush(stderr);
_exit(1);
}
} else if (pid == -1) {
// Error
e = errno;
throw SystemException("Cannot fork a new process", e);
} else {
// Parent
UPDATE_TRACE_POINT();
FileDescriptor feedbackFd = fds[0];
vector<string> args;
bool result = false;
ScopeGuard guard(boost::bind(&WatchdogLauncher::killProcessGroupAndWait, &pid, 0));
fds[1].close();
P_LOG_FILE_DESCRIPTOR_PURPOSE(feedbackFd, "WatchdogLauncher: feedback FD");
/****** Send arguments to watchdog through the feedback channel ******/
UPDATE_TRACE_POINT();
/* Here we don't care about EPIPE and ECONNRESET errors. The watchdog
* could have sent an error message over the feedback fd without
* reading the arguments. We'll notice that later.
*/
try {
writeScalarMessage(feedbackFd, config.toStyledString());
} catch (const SystemException &e) {
if (e.code() != EPIPE && e.code() != ECONNRESET) {
inspectWatchdogCrashReason(pid);
}
}
/****** Read agents information report ******/
boost::this_thread::restore_interruption ri(di);
boost::this_thread::restore_syscall_interruption rsi(dsi);
UPDATE_TRACE_POINT();
try {
result = readArrayMessage(feedbackFd, args);
} catch (const SystemException &ex) {
if (ex.code() == ECONNRESET) {
inspectWatchdogCrashReason(pid);
} else {
killProcessGroupAndWait(&pid, 5000);
guard.clear();
throw SystemException("Unable to start the " PROGRAM_NAME " watchdog: "
"unable to read its startup information report",
ex.code());
}
}
if (!result) {
UPDATE_TRACE_POINT();
inspectWatchdogCrashReason(pid);
}
if (args[0] == "Agents information") {
UPDATE_TRACE_POINT();
if (args.size() != 1) {
throw RuntimeException("Unable to start the " PROGRAM_NAME " watchdog: "
"it belongs to an incompatible version of " SHORT_PROGRAM_NAME
". Please fully upgrade " SHORT_PROGRAM_NAME ".");
}
string jsonData;
try {
result = readScalarMessage(feedbackFd, jsonData);
} catch (const SystemException &ex) {
if (ex.code() == ECONNRESET) {
inspectWatchdogCrashReason(pid);
} else {
killProcessGroupAndWait(&pid, 5000);
guard.clear();
throw SystemException("Unable to start the " PROGRAM_NAME " watchdog: "
"unable to read its startup information report",
ex.code());
}
}
if (!result) {
UPDATE_TRACE_POINT();
inspectWatchdogCrashReason(pid);
}
Json::Value doc;
Json::Reader reader;
if (!reader.parse(jsonData, doc)) {
throw RuntimeException("Unable to start the " PROGRAM_NAME " watchdog: "
"unable to parse its startup information report as valid JSON: "
+ reader.getFormattedErrorMessages() + "\n"
"Raw data: \"" + cEscapeString(jsonData) + "\"");
}
mPid = pid;
this->feedbackFd = feedbackFd;
mCoreAddress = doc["core_address"].asString();
mCorePassword = doc["core_password"].asString();
mInstanceDir = doc["instance_dir"].asString();
guard.clear();
} else if (args[0] == "Watchdog startup error") {
killProcessGroupAndWait(&pid, 5000);
guard.clear();
throw RuntimeException("Unable to start the " PROGRAM_NAME " watchdog "
"because it encountered the following error during startup: " +
args[1]);
} else if (args[0] == "system error") {
killProcessGroupAndWait(&pid, 5000);
guard.clear();
throw SystemException(args[1], atoi(args[2]));
} else if (args[0] == "exec error") {
e = atoi(args[1]);
killProcessGroupAndWait(&pid, 5000);
guard.clear();
if (e == ENOENT) {
throwEnrichedWatchdogFailReason(locator, "Executable " + agentFilename + " not found.");
} else {
throw SystemException("Unable to start the " PROGRAM_NAME " watchdog (" +
agentFilename + ")", e);
}
} else {
UPDATE_TRACE_POINT();
killProcessGroupAndWait(&pid, 5000);
guard.clear();
throw RuntimeException("The " PROGRAM_NAME " watchdog sent an unknown feedback message '"
+ args[0] + "'");
}
}
}
/**
* Close any file descriptors that this object has, and make it so that
* the destructor doesn't try to shut down the watchdog.
*
* @post getPid() == 0
*/
void detach() {
feedbackFd.close();
mPid = 0;
}
};
} // namespace Passenger
#endif /* __cplusplus */
#endif /* _PASSENGER_WATCHDOG_LAUNCHER_HPsg */
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