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// Copyright (c) 1999-2002 David Muse
// See the COPYING file for more information.
#ifndef RUDIMENTS_DAEMONPROCESS_H
#define RUDIMENTS_DAEMONPROCESS_H
#include <rudiments/private/daemonprocessincludes.h>
// Daemons are long running processes which often detach themselves from
// the controlling terminal and run in the background. They are frequently
// started at boot time and run until the machine is shut down.
//
// Daemons typically perform "housecleaning" tasks or serve data to client
// programs. See the server class.
class daemonprocess {
public:
daemonprocess();
virtual ~daemonprocess();
int checkForPidFile(const char *filename) const;
// Checks for filename "filename" and reads the
// process id out of it, if it exists. Returns
// the process id on success or -1 on failure.
bool createPidFile(const char *filename,
mode_t permissions) const;
// Create's file "filename" with permissions
// "permissions" and puts the current process
// id in it. Note that when you delete this
// file during shutdown you must use the full
// pathname since the detach() method below
// changes directories to "/". Returns true on
// success and false on failure.
void detach() const;
// Detach from the controlling terminal and
// process and run in the background. Also
// change directories to "/" and set the file
// creation mask such that all files are
// created -rw-rw-rw and all directories
// drwxrwxrwx.
// These methods allow the daemon to run as a different
// user or group than the one that started the process.
// They have no effect unless the process is started
// by the root user.
//
// These methods return 1 on success, 0 on failure and
// -1 on error.
int runAsUser(const char *username) const;
// Note that runAsUser() uses the passwdentry
// class. If you are using this method in a
// multithreaded application, you may need to
// supply the passwdentry classes a mutex.
// See passwdentry.h for more detail.
int runAsGroup(const char *groupname) const;
// Note that runAsGroup() uses the groupentry
// class. If you are using this method in a
// multithreaded application, you may need to
// supply the groupentry classes a mutex.
// See groupentry.h for more detail.
int runAsUserId(uid_t uid) const;
int runAsGroupId(gid_t gid) const;
static void handleShutDown(void *shutdownfunction);
// This method allows you to designate a
// function to run when the daemon is killed.
static void handleCrash(void *crashfunction);
// This method allows you to designate a
// function to run if the daemon crashes.
static void waitForChildren();
// This method causes the daemon to wait
// on child processes which have exited,
// preventing so-called "zombie" processes
// from occurring. This method is called
// in the constructor and is thus the default
// behavior of this class.
static void dontWaitForChildren();
// This method causes the daemon not to
// wait on child processes which have exited.
// Ordinarily, you'd want to wait on child
// processes, but this interferes with the
// behavior of WEXITSTATUS() after a call to
// system() (and possibly other calls). This
// method allows you to disable waiting on
// child processes.
#include <rudiments/private/daemonprocess.h>
};
#endif
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