#include <fcntl.h>
#include <errno.h>
#include <signal.h>
+#include <sstream>
#include "../Utils/Exception.hh"
#include "../Utils/membind.hh"
// senf::Daemon
prefix_ senf::Daemon::~Daemon()
-{}
+{
+ if (! pidfile_.empty())
+ LIBC_CALL( ::unlink, (pidfile_.c_str()) );
+}
prefix_ void senf::Daemon::daemonize(bool v)
{
}
}
-prefix_ void senf::Daemon::pidFile(std::string f, bool unique)
+prefix_ void senf::Daemon::pidFile(std::string f)
{
pidfile_ = f;
- unique_ = unique;
}
prefix_ void senf::Daemon::detach()
{
- LIBC_CALL_RV( nul, ::open, ("/dev/null", O_WRONLY) );
- LIBC_CALL( ::dup2, (nul, 1) );
- LIBC_CALL( ::dup2, (nul, 2) );
- LIBC_CALL( ::close, (nul) );
+ if (daemonize_) {
+ LIBC_CALL_RV( nul, ::open, ("/dev/null", O_WRONLY) );
+ LIBC_CALL( ::dup2, (nul, 1) );
+ LIBC_CALL( ::dup2, (nul, 2) );
+ LIBC_CALL( ::close, (nul) );
+ }
}
prefix_ int senf::Daemon::start(int argc, char const ** argv)
try {
# endif
- configure();
- if (daemonize_)
- fork();
- if (! pidfile_.empty())
- pidfileCreate();
- main();
+ configure();
+
+ if (daemonize_)
+ fork();
+ if (! pidfile_.empty() && ! pidfileCreate()) {
+ std::cerr << "\n*** PID file '" << pidfile_ << "' creation failed. Daemon running ?"
+ << std::endl;
+ return 1;
+ }
+
+ main();
# ifdef NDEBUG
}
// protected members
prefix_ senf::Daemon::Daemon()
- : argc_(0), argv_(0), daemonize_(true), stdout_(-1), stderr_(-1), pidfile_(""), unique_(true),
+ : argc_(0), argv_(0), daemonize_(true), stdout_(-1), stderr_(-1), pidfile_(""),
detached_(false)
{}
return;
}
+ // Ouch ... ensure, the daemon watcher does not remove the pidfile ...
+ pidfile_ = "";
+
LIBC_CALL( ::close, (coutpipe[1]) );
LIBC_CALL( ::close, (cerrpipe[1]) );
detail::DaemonWatcher watcher (pid, coutpipe[0], cerrpipe[0]);
watcher.run();
- ::exit(0);
-
+ ::_exit(0);
}
-prefix_ void senf::Daemon::pidfileCreate()
-{}
+prefix_ bool senf::Daemon::pidfileCreate()
+{
+ // Create temporary file pidfile_.hostname.pid and hard-link it to pidfile_ If the hardlink
+ // fails, the pidfile exists. If the link count of the temporary file is not 2 after this, there
+ // was some race condition, probably over NFS.
+
+ std::string tempname;
+
+ {
+ char hostname[HOST_NAME_MAX+1];
+ LIBC_CALL( ::gethostname, (hostname, HOST_NAME_MAX+1) );
+ hostname[HOST_NAME_MAX] = 0;
+ std::stringstream tempname_s;
+ tempname_s << pidfile_ << "." << hostname << "." << ::getpid();
+ tempname = tempname_s.str();
+ }
+
+ while (1) {
+ {
+ std::ofstream pidf (tempname.c_str());
+ pidf << ::getpid() << std::endl;
+ }
+
+ if (::link(tempname.c_str(), pidfile_.c_str()) < 0) {
+ if (errno != EEXIST)
+ throwErrno("::link()");
+ }
+ else {
+ struct ::stat s;
+ LIBC_CALL( ::stat, (tempname.c_str(), &s) );
+ LIBC_CALL( ::unlink, (tempname.c_str()) );
+ return s.st_nlink == 2;
+ }
+
+ // pidfile exists. Check, whether the pid in the pidfile still exists.
+ {
+ int old_pid (-1);
+ std::ifstream pidf (pidfile_.c_str());
+ if ( ! (pidf >> old_pid)
+ || old_pid < 0
+ || ::kill(old_pid, 0) >= 0
+ || errno == EPERM )
+ return false;
+ }
+
+ // If we reach this point, the pid file exists but the process mentioned within the
+ // pid file does *not* exists. We assume, the pid file to be stale.
+
+ // I hope, the following procedure is without race condition: We remove our generated
+ // temporary pid file and recreate it as hard-link to the old pid file. Now we check, that
+ // the hard-link count of this file is 2. If it is not, we terminate, since someone else
+ // must have already created his hardlink. We then truncate the file and write our pid.
+
+ LIBC_CALL( ::unlink, (tempname.c_str() ));
+ if (::link(pidfile_.c_str(), tempname.c_str()) < 0) {
+ if (errno != ENOENT) throwErrno("::link()");
+ // Hmm ... the pidfile mysteriously disappeared ... try again.
+ continue;
+ }
+
+ {
+ struct ::stat s;
+ LIBC_CALL( ::stat, (tempname.c_str(), &s) );
+ if (s.st_nlink != 2) {
+ LIBC_CALL( ::unlink, (tempname.c_str()) );
+ return false;
+ }
+ }
+
+ {
+ std::ofstream pidf (tempname.c_str());
+ pidf << ::getpid() << std::endl;
+ }
+
+ LIBC_CALL( ::unlink, (tempname.c_str()) );
+ break;
+ }
+ return true;
+}
///////////////////////////////////////////////////////////////////////////
// senf::detail::DaemonWatcher
prefix_ senf::detail::DaemonWatcher::DaemonWatcher(int pid, int coutpipe, int cerrpipe)
- : childPid_(pid), coutpipe_(coutpipe), cerrpipe_(cerrpipe),
- coutForwarder_(coutpipe_, 1, senf::membind(&DaemonWatcher::pipeClosed, this)),
- cerrForwarder_(cerrpipe_, 2, senf::membind(&DaemonWatcher::pipeClosed, this))
+ : childPid_(pid), coutpipe_(coutpipe), cerrpipe_(cerrpipe), sigChld_(false),
+ coutForwarder_(coutpipe_, 1, boost::bind(&DaemonWatcher::pipeClosed, this, 1)),
+ cerrForwarder_(cerrpipe_, 2, boost::bind(&DaemonWatcher::pipeClosed, this, 2))
{}
prefix_ void senf::detail::DaemonWatcher::run()
{
- Scheduler::instance().registerSignal(SIGCHLD, senf::membind(&DaemonWatcher::childDied, this));
+ Scheduler::instance().registerSignal(SIGCHLD, senf::membind(&DaemonWatcher::sigChld, this));
Scheduler::instance().process();
}
////////////////////////////////////////
// private members
-prefix_ void senf::detail::DaemonWatcher::pipeClosed()
+prefix_ void senf::detail::DaemonWatcher::pipeClosed(int id)
{
- if (! timerRunning_) {
- Scheduler::instance().timeout(Scheduler::instance().eventTime() + ClockService::seconds(1),
- senf::membind(&DaemonWatcher::childOk, this));
- timerRunning_ = true;
+ switch (id) {
+ case 1 : coutpipe_ = -1; break;
+ case 2 : cerrpipe_ = -1; break;
+ }
+
+ if (coutpipe_ == -1 && cerrpipe_ == -1) {
+ if (sigChld_)
+ childDied(); // does not return
+ Scheduler::instance().timeout(
+ Scheduler::instance().eventTime() + ClockService::seconds(1),
+ senf::membind(&DaemonWatcher::childOk, this));
}
}
+prefix_ void senf::detail::DaemonWatcher::sigChld()
+{
+ sigChld_ = true;
+ if (coutpipe_ == -1 && cerrpipe_ == -1)
+ childDied(); // does not return
+}
+
prefix_ void senf::detail::DaemonWatcher::childDied()
{
int status (0);
::signal(WTERMSIG(status),SIG_DFL);
::kill(::getpid(), WTERMSIG(status));
// should not be reached
- ::exit(1);
+ ::_exit(1);
}
if (WEXITSTATUS(status) == 0)
- ::exit(1);
- ::exit(WEXITSTATUS(status));
+ ::_exit(1);
+ ::_exit(WEXITSTATUS(status));
}
prefix_ void senf::detail::DaemonWatcher::childOk()
projects / senf.git / commitdiff