Merge pull request #2182

2fac03e6 Update monerod systemd service file (Erik de Castro Lopo)
51efb217 daemon: Add ability to write a PID file (Erik de Castro Lopo)
This commit is contained in:
Riccardo Spagni 2017-08-07 15:06:59 +02:00
commit 64ebeb5aa5
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4 changed files with 61 additions and 19 deletions

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@ -43,6 +43,10 @@ namespace daemonizer
"detach"
, "Run as daemon"
};
const command_line::arg_descriptor<std::string> arg_pidfile = {
"pidfile"
, "File path to write the daemon's PID to (optional, requires --detach)"
};
const command_line::arg_descriptor<bool> arg_non_interactive = {
"non-interactive"
, "Run non-interactive"
@ -55,6 +59,7 @@ namespace daemonizer
)
{
command_line::add_arg(normal_options, arg_detach);
command_line::add_arg(normal_options, arg_pidfile);
command_line::add_arg(normal_options, arg_non_interactive);
}
@ -80,7 +85,12 @@ namespace daemonizer
if (command_line::has_arg(vm, arg_detach))
{
tools::success_msg_writer() << "Forking to background...";
posix::fork();
std::string pidfile;
if (command_line::has_arg(vm, arg_pidfile))
{
pidfile = command_line::get_arg(vm, arg_pidfile);
}
posix::fork(pidfile);
auto daemon = executor.create_daemon(vm);
return daemon.run();
}

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@ -21,15 +21,43 @@
namespace posix {
namespace {
void quit(std::string const & message)
void quit(const std::string & message)
{
LOG_ERROR(message);
throw std::runtime_error(message);
}
}
void fork()
void fork(const std::string & pidfile)
{
// If a PID file is specified, we open the file here, because
// we can't report errors after the fork operation.
// When we fork, we close thise file in each of the parent
// processes.
// Only in the final child process do we write the PID to the
// file (and close it).
std::ofstream pidofs;
if (! pidfile.empty ())
{
int oldpid;
std::ifstream pidrifs;
pidrifs.open(pidfile, std::fstream::in);
if (! pidrifs.fail())
{
// Read the PID and send signal 0 to see if the process exists.
if (pidrifs >> oldpid && oldpid > 1 && kill(oldpid, 0) == 0)
{
quit("PID file " + pidfile + " already exists and the PID therein is valid");
}
pidrifs.close();
}
pidofs.open(pidfile, std::fstream::out | std::fstream::trunc);
if (pidofs.fail())
{
quit("Failed to open specified PID file for writing");
}
}
// Fork the process and have the parent exit. If the process was started
// from a shell, this returns control to the user. Forking a new process is
// also a prerequisite for the subsequent call to setsid().
@ -38,7 +66,7 @@ void fork()
if (pid > 0)
{
// We're in the parent process and need to exit.
//
pidofs.close();
// When the exit() function is used, the program terminates without
// invoking local variables' destructors. Only global variables are
// destroyed.
@ -59,6 +87,7 @@ void fork()
{
if (pid > 0)
{
pidofs.close();
exit(0);
}
else
@ -67,6 +96,13 @@ void fork()
}
}
if (! pidofs.fail())
{
int pid = ::getpid();
pidofs << pid << std::endl;
pidofs.close();
}
// Close the standard streams. This decouples the daemon from the terminal
// that started it.
close(0);

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@ -27,12 +27,13 @@
// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#pragma once
#include <string>
#ifndef WIN32
namespace posix {
void fork();
void fork(const std::string & pidfile);
}

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@ -8,15 +8,10 @@ Group=monero
WorkingDirectory=~
Type=forking
ExecStart=/usr/bin/monerod --config-file /etc/monerod.conf --detach
PIDFile=/var/run/monerod.pid
# This is necessary because monerod does not yet support
# writing a PID file, which means systemd tries to guess the PID
# by default, but it guesses wrong (sometimes, depending on
# random timing of events), because the daemon forks twice.
# The ultimate fix is for the daemon to write a PID file, and
# a workaround is to disable the guessing feature in systemd.
GuessMainPID=no
ExecStart=/usr/bin/monerod --config-file /etc/monerod.conf \
--detach --pidfile /var/run/monerod.pid
[Install]
WantedBy=multi-user.target