dudki: initial import into svn repository

9 files changed, 700 insertions, 0 deletions

diff --git a/src/.gitignore b/src/.gitignore
new file mode 100644
index 0000000..e26d996
--- a/dev/null
+++ b/src/.gitignore
@@ -0,0 +1,5 @@
+.deps
+Makefile
+Makefile.in
+COPYING.cc
+dudki
diff --git a/src/Makefile.am b/src/Makefile.am
new file mode 100644
index 0000000..3810272
--- a/dev/null
+++ b/src/Makefile.am
@@ -0,0 +1,18 @@
+sbin_PROGRAMS = dudki
+
+INCLUDES = ${DOTCONF_CFLAGS}
+LIBS += ${DOTCONF_LIBS}
+AM_CPPFLAGS = \
+              -DDEFAULT_CONF_FILE=\"${sysconfdir}/${PACKAGE}.conf\" \
+              -DDEFAULT_PID_FILE=\"/var/run/${PACKAGE}.pid\"
+
+dudki_SOURCES = dudki.cc \
+        process.cc process.h \
+        configuration.cc configuration.h \
+        util.cc util.h \
+        COPYING.cc
+
+COPYING.cc: ${top_srcdir}/COPYING
+        echo "const char * COPYING =" >$@ || (rm $@;exit 1)
+        sed 's/"/\\"/g' $< | sed 's/^/\"/' | sed 's/$$/\\n\"/' >>$@ || (rm $@;exit 1)
+        echo ";" >>$@ || (rm $@;exit 1)
diff --git a/src/configuration.cc b/src/configuration.cc
new file mode 100644
index 0000000..eb010c1
--- a/dev/null
+++ b/src/configuration.cc
@@ -0,0 +1,149 @@
+#include <stdexcept>
+using namespace std;
+#include <dotconf.h>
+#include "configuration.h"
+
+#ifndef DEFAULT_PID_FILE
+# define DEFAULT_PID_FILE "/var/run/dudki.pid"
+#endif
+
+configuration::configuration()
+    : check_interval(60), pidfile(DEFAULT_PID_FILE),
+    daemonize(true) {
+    }
+
+enum dc_ctx {
+    DCC_ROOT = 1,
+    DCC_PROCESS = 2
+};
+struct dc_context {
+    dc_ctx ctx;
+    configuration* cf;
+    process* ps;
+
+    dc_context()
+        : ctx(DCC_ROOT), cf(NULL), ps(NULL) { }
+};
+
+static DOTCONF_CB(dco_check_interval) { dc_context *dcc = (dc_context*)ctx;
+    dcc->cf->check_interval = cmd->data.value;
+    return NULL;
+}
+static DOTCONF_CB(dco_daemonize) { dc_context *dcc = (dc_context*)ctx;
+    dcc->cf->daemonize = cmd->data.value;
+    return NULL;
+}
+
+static DOTCONF_CB(dco_pid_file) { dc_context *dcc = (dc_context*)ctx;
+    switch(dcc->ctx) {
+        case DCC_ROOT:
+            dcc->cf->pidfile = cmd->data.str;
+            break;
+        case DCC_PROCESS:
+            dcc->ps->pidfile = cmd->data.str;
+            break;
+        default:
+            return "Unexpected PidFile";
+    }
+    return NULL;
+}
+static DOTCONF_CB(dco_mailto_header) { dc_context *dcc = (dc_context*)ctx;
+    if(cmd->arg_count!=2)
+        return "Invalid number of arguments";
+    string h = cmd->data.list[0];
+    string v = cmd->data.list[1];
+    switch(dcc->ctx) {
+        case DCC_ROOT:
+            dcc->cf->mailto_headers[h] = v;
+            break;
+        case DCC_PROCESS:
+            dcc->ps->mailto_headers[h] = v;
+            break;
+        default:
+            return "Unexpected MailtoHeader";
+    }
+    return NULL;
+}
+static DOTCONF_CB(dco_notify) { dc_context *dcc = (dc_context*)ctx;
+    switch(dcc->ctx) {
+        case DCC_ROOT:
+            dcc->cf->notify = cmd->data.str;
+            break;
+        case DCC_PROCESS:
+            dcc->ps->notify = cmd->data.str;
+            break;
+        default:
+            return "Unexpected Notify";
+    }
+    return NULL;
+}
+
+static DOTCONF_CB(dco_process) { dc_context *dcc = (dc_context*)ctx;
+    string id = cmd->data.str;
+    if(id[id.length()-1]=='>')
+        id.erase(id.length()-1);
+    dcc->ps = &(dcc->cf->processes[id]);
+    dcc->ctx = DCC_PROCESS;
+    return NULL;
+}
+static DOTCONF_CB(dco__process) { dc_context *dcc = (dc_context*)ctx;
+    dcc->ps = NULL;
+    dcc->ctx = DCC_ROOT;
+    return NULL;
+}
+
+static DOTCONF_CB(dco_restart_command) { dc_context *dcc = (dc_context*)ctx;
+    dcc->ps->restart_cmd = cmd->data.str;
+    return NULL;
+}
+static DOTCONF_CB(dco_user) { dc_context *dcc = (dc_context*)ctx;
+    dcc->ps->user = cmd->data.str;
+    return NULL;
+}
+static DOTCONF_CB(dco_group) { dc_context *dcc = (dc_context*)ctx;
+    dcc->ps->group = cmd->data.str;
+    return NULL;
+}
+static DOTCONF_CB(dco_chroot) { dc_context *dcc = (dc_context*)ctx;
+    dcc->ps->chroot = cmd->data.str;
+    return NULL;
+}
+
+static const configoption_t dc_options[] = {
+    { "CheckInterval", ARG_INT, dco_check_interval, NULL, DCC_ROOT },
+    { "Daemonize", ARG_TOGGLE, dco_daemonize, NULL, DCC_ROOT },
+    { "PidFile", ARG_STR, dco_pid_file, NULL, DCC_ROOT|DCC_PROCESS },
+    { "MailtoHeader", ARG_STR, dco_mailto_header, NULL, DCC_ROOT|DCC_PROCESS },
+    { "Notify", ARG_STR, dco_notify, NULL, DCC_ROOT|DCC_PROCESS },
+    { "<Process", ARG_STR, dco_process, NULL, DCC_ROOT },
+    {  "RestartCommand", ARG_STR, dco_restart_command, NULL, DCC_PROCESS },
+    {  "User", ARG_STR, dco_user, NULL, DCC_PROCESS },
+    {  "Group", ARG_STR, dco_group, NULL, DCC_PROCESS },
+    {  "Chroot", ARG_STR, dco_chroot, NULL, DCC_PROCESS },
+    { "</Process>", ARG_NONE, dco__process, NULL, DCC_PROCESS },
+    LAST_OPTION
+};
+
+static const char *dc_context_checker(command_t *cmd,unsigned long mask) {
+    dc_context *dcc = (dc_context*)cmd->context;
+    if( (mask==CTX_ALL) || ((mask&dcc->ctx)==dcc->ctx) )
+        return NULL;
+    return "misplaced option";
+}
+static FUNC_ERRORHANDLER(dc_error_handler) {
+    throw runtime_error(string("error parsing config file: ")+msg);
+}
+    
+void configuration::parse(const string& cfile) {
+    struct dc_context dcc;
+    dcc.cf = this;
+    dcc.ctx = DCC_ROOT;
+    configfile_t *cf = dotconf_create((char*)cfile.c_str(),dc_options,(context_t*)&dcc,CASE_INSENSITIVE);
+    if(!cf)
+        throw runtime_error(string(__PRETTY_FUNCTION__)+": failed to dotconf_create()");
+    cf->errorhandler = (dotconf_errorhandler_t) dc_error_handler;
+    cf->contextchecker = (dotconf_contextchecker_t) dc_context_checker;
+    if(!dotconf_command_loop(cf))
+        throw runtime_error(string(__PRETTY_FUNCTION__)+": failed to dotconf_command_loop()");
+    dotconf_cleanup(cf);
+}
diff --git a/src/configuration.h b/src/configuration.h
new file mode 100644
index 0000000..314af92
--- a/dev/null
+++ b/src/configuration.h
@@ -0,0 +1,23 @@
+#ifndef __CONFIGURATION_H
+#define __CONFIGURATION_H
+
+#include <string>
+using namespace std;
+#include "process.h"
+
+class configuration {
+    public:
+        processes_t processes;
+
+        int check_interval;
+        string pidfile;
+        bool daemonize;
+        headers_t mailto_headers;
+        string notify;
+
+        configuration();
+
+        void parse(const string& cfile);
+};
+
+#endif /* __CONFIGURATION_H */
diff --git a/src/dudki.cc b/src/dudki.cc
new file mode 100644
index 0000000..3c50e56
--- a/dev/null
+++ b/src/dudki.cc
@@ -0,0 +1,244 @@
+#include <unistd.h>
+#include <signal.h>
+#include <syslog.h>
+#include <iostream>
+#include <fstream>
+#include <stdexcept>
+using namespace std;
+#include "configuration.h"
+#include "util.h"
+
+#include "config.h"
+#ifdef HAVE_GETOPT_H
+# include <getopt.h>
+#endif
+
+#ifndef DEFAULT_CONF_FILE
+# define DEFAULT_CONF_FILE "/etc/dudki.conf"
+#endif
+
+#define PHEADER PACKAGE " Version " VERSION
+#define PCOPY   "Copyright (c) 2004 Klever Group"
+
+bool finishing = false;
+static char **_argv = NULL;
+
+static void lethal_signal_handler(int signum) {
+    syslog(LOG_NOTICE,"Lethal signal received. Terminating.");
+    finishing = true;
+}
+static void sighup_handler(int signum) {
+    syslog(LOG_NOTICE,"SUGHUP received, reloading.");
+    execvp(_argv[0],_argv);
+}
+
+void check_herd(configuration& config) {
+    for(processes_t::iterator i=config.processes.begin();i!=config.processes.end();++i)
+        i->second.check(i->first,config);
+}
+
+void signal_self(const configuration& config,int signum) {
+    ifstream pids(config.pidfile.c_str(),ios::in);
+    if(!pids)
+        throw runtime_error("Can't detect running instance");
+    pid_t pid = 0;
+    pids >> pid;
+    if(!pid)
+        throw runtime_error("Can't detect running instance");
+    if(pid==getpid())
+        throw 0;
+    if(kill(pid,signum))
+        throw runtime_error("Failed to signal running instance");
+}
+
+int main(int argc,char **argv) {
+    try {
+        _argv = new char*[argc+1];
+        if(!_argv)
+            throw runtime_error("memory allocation problem at the very start");
+        memmove(_argv,argv,sizeof(*_argv)*(argc+1));
+        string config_file = DEFAULT_CONF_FILE;
+        enum {
+            op_default,
+            op_work,
+            op_hup,
+            op_term,
+            op_check,
+            op_ensure,
+            op_test
+        } op = op_default;
+        while(true) {
+        #defineSHORTOPTSTRING "f:hVLrkcet"
+#ifdef HAVE_GETOPT_LONG
+            static struct option opts[] = {
+                { "help", no_argument, 0, 'h' },
+                { "usage", no_argument, 0, 'h' },
+                { "version", no_argument, 0, 'V' },
+                { "license", no_argument, 0, 'L' },
+                { "config", required_argument, 0, 'f' },
+                { "kill", no_argument, 0, 'k' },
+                { "reload", no_argument, 0, 'r' },
+                { "check", no_argument, 0, 'c' },
+                { "ensure", no_argument, 0, 'e' },
+                { "test", no_argument, 0, 't' },
+                { NULL, 0, 0, 0 }
+            };
+            int c = getopt_long(argc,argv,SHORTOPTSTRING,opts,NULL);
+#else /* !HAVE_GETOPT_LONG */
+            int c = getopt(argc,argv,SHORTOPTSTRING);
+#endif /* /HAVE_GETOPT_LONG */
+            if(c==-1)
+                break;
+            switch(c) {
+                case 'h':
+                    cerr << PHEADER << endl
+                        << PCOPY << endl << endl <<
+#ifdef HAVE_GETOPT_LONG
+                        " -h, --help\n"
+                        " --usage         display this text\n"
+                        " -V, --version   display version number\n"
+                        " -L, --license   show license\n"
+                        " -f filename, --config=filename\n"
+                        "                 specify the configuration file to use\n"
+                        "\n"
+                        " -k, --kill      stop running instance\n"
+                        " -r, --reload    reload running instance (send SIGHUP)\n"
+                        " -c, --check     check if dudki is running\n"
+                        " -e, --ensure    ensure that dudki is running\n"
+                        " -t, --test      test configuration file and exit"
+#else /* !HAVE_GETOPT_LONG */
+                        " -h              display this text\n"
+                        " -V              display version number\n"
+                        " -L              show license\n"
+                        " -f filename     specify the configuration file to use\n"
+                        "\n"
+                        " -k              stop running instance\n"
+                        " -r              reload running instance (send SIGHUP)\n"
+                        " -c              check if dudki is running\n"
+                        " -e              ensure that dudki is running\n"
+                        " -t              test configuration file and exit"
+#endif /* /HAVE_GETOPT_LONG */
+                        << endl;
+                    exit(0);
+                    break;
+                case 'V':
+                    cerr << VERSION << endl;
+                    exit(0);
+                    break;
+                case 'L':
+                    extern const char *COPYING;
+                    cerr << COPYING << endl;
+                    exit(0);
+                    break;
+                case 'f':
+                    config_file = optarg;
+                    break;
+                case 'k':
+                    if(op!=op_default) {
+                        cerr << "Can't obey two or more orders at once" << endl;
+                        exit(1);
+                    }
+                    op = op_term;
+                    break;
+                case 'r':
+                    if(op!=op_default) {
+                        cerr << "Can't obey two or more orders at once" << endl;
+                        exit(1);
+                    }
+                    op = op_hup;
+                    break;
+                case 'c':
+                    if(op!=op_default) {
+                        cerr << "Can't obey two or more orders at once" << endl;
+                        exit(1);
+                    }
+                    op = op_check;
+                    break;
+                case 'e':
+                    if(op!=op_default) {
+                        cerr << "Can't obey two or more orders at once" << endl;
+                        exit(1);
+                    }
+                    op = op_ensure;
+                    break;
+                case 't':
+                    if(op!=op_default) {
+                        cerr << "Can't obey two or more orders at once" << endl;
+                        exit(1);
+                    }
+                    op = op_test;
+                    break;
+                default:
+                    cerr << "Huh??" << endl;
+                    exit(1);
+                    break;
+            }
+        }
+        const char *sid = *argv;
+        const char *t;
+        while(t = index(sid,'/')) {
+            sid = t; sid++;
+        }
+        openlog(sid,LOG_CONS|LOG_PERROR|LOG_PID,LOG_DAEMON);
+        configuration config;
+        config.parse(config_file);
+        switch(op) {
+            case op_test:
+                cerr << "Configuration OK" << endl;
+                break;
+            case op_hup:
+                signal_self(config,SIGHUP);
+                break;
+            case op_term:
+                signal_self(config,SIGTERM);
+                break;
+            case op_check:
+                try{
+                    signal_self(config,0);
+                    exit(0);
+                }catch(exception& e) {
+                    exit(1);
+                }
+            case op_ensure:
+                try {
+                    signal_self(config,0);
+                    break;
+                }catch(exception& e) {
+                    syslog(LOG_NOTICE,"The dudki process is down, taking its place");
+                    config.daemonize = true;
+                }catch(int zero) {
+                    // we throw zero in case we're ensuring that this very process is running.
+                    // we don't have to daemonize if we're daemonic.
+                    config.daemonize = false;
+                }
+            case op_default:
+            case op_work:
+                {
+                    if(config.daemonize) {
+                        pid_t pf = fork();
+                        if(pf<0)
+                            throw runtime_error(string(__PRETTY_FUNCTION__)+": failed to fork()");
+                        if(pf) {
+                            _exit(0);
+                        }
+                    }
+                    pid_file pidfile;
+                    pidfile.set(config.pidfile);
+                    signal(SIGINT,lethal_signal_handler);
+                    signal(SIGABRT,lethal_signal_handler);
+                    signal(SIGTERM,lethal_signal_handler);
+                    signal(SIGHUP,sighup_handler);
+                    while(!finishing) {
+                        check_herd(config);
+                        sleep(config.check_interval);
+                    }
+                }
+                break;
+            default:
+                throw runtime_error(string(__PRETTY_FUNCTION__)+": internal error");
+        }
+    }catch(exception& e) {
+        cerr << "Oops: " << e.what() << endl;
+        return 1;
+    }
+}
diff --git a/src/process.cc b/src/process.cc
new file mode 100644
index 0000000..fda35e8
--- a/dev/null
+++ b/src/process.cc
@@ -0,0 +1,184 @@
+#include <stdio.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <signal.h>
+#include <pwd.h>
+#include <grp.h>
+#include <sys/wait.h>
+#include <syslog.h>
+#include <errno.h>
+#include <iostream>
+#include <fstream>
+#include <stdexcept>
+using namespace std;
+#include "process.h"
+#include "configuration.h"
+
+void process::check(const string& id,configuration& config) {
+    bool running = false;
+    ifstream pids(pidfile.c_str(),ios::in);
+    if(pids) {
+        pid_t pid = 0;
+        pids >> pid;
+        pids.close();
+        if(pid) {
+            if(!kill(pid,0)) {
+                running = true;
+            }
+        }
+    }
+    if(running){
+        patience = 0;
+    }else{
+        if(patience>60) { // TODO: configurable
+            patience = 0;
+        }else{
+            if(patience<10) { // TODO: configurable
+                syslog(LOG_NOTICE,"The process '%s' is down, trying to launch.",id.c_str());
+                do_notify(id,"Starting up",
+                        "The named process seems to be down. Dudki will try\n"
+                        "to revive it by running the specified command.\n",
+                        config);
+                try {
+                    launch(id,config);
+                }catch(exception& e) {
+                    syslog(LOG_ERR,"Error trying to launch process '%s': %s",id.c_str(),e.what());
+                }
+            }else if(patience==10){ // TODO: configurable like the above
+                syslog(LOG_NOTICE,"Giving up on process '%s' for a while",id.c_str());
+                do_notify(id,"Giving up",
+                        "After a number of attempts to relaunch the named process\n"
+                        "It still seems to be down. Dudki is giving up attempts\n"
+                        "to revive the process for a while.\n",
+                        config);
+            }
+            patience++;
+        }
+    }
+}
+
+void process::launch(const string& id,configuration& config) {
+    uid_t uid = 0;
+    if(!user.empty()) {
+        struct passwd *ptmp = getpwnam(user.c_str());
+        if(ptmp) {
+            uid = ptmp->pw_uid;
+        }else{
+            errno=0;
+            uid = strtol(user.c_str(),NULL,0);
+            if(errno)
+                throw runtime_error("Failed to resolve User value to uid");
+        }
+    }
+    gid_t gid = 0;
+    if(!group.empty()) {
+        struct group *gtmp = getgrnam(group.c_str());
+        if(gtmp) {
+            gid = gtmp->gr_gid;
+        }else{
+            errno = 0;
+            gid = strtol(group.c_str(),NULL,0);
+            if(errno)
+                throw runtime_error("Failed to reslove Group value to gid");
+        }
+    }
+    pid_t p = fork();
+    if(p<0)
+        throw runtime_error(string(__PRETTY_FUNCTION__)+": failed to fork()");
+    if(!p) {
+        // child
+        try {
+            setsid();
+            if(!chroot.empty()) {
+                if(::chroot(chroot.c_str()))
+                    throw runtime_error(string(__PRETTY_FUNCTION__)+": failed to chroot()");
+            }
+            if(!group.empty()) {
+                // TODO: initgroups()?
+                if((getgid()!=gid) && setgid(gid))
+                    throw runtime_error(string(__PRETTY_FUNCTION__)+": failed to setgid()");
+            }
+            if(!user.empty()) {
+                if((getuid()!=uid) && setuid(uid))
+                    throw runtime_error(string(__PRETTY_FUNCTION__)+": failed to setuid()");
+            }
+            char *argv[] = { "/bin/sh", "-c", (char*)restart_cmd.c_str(), NULL };
+            close(0); close(1); close(2);
+            execv("/bin/sh",argv);
+        }catch(exception& e) {
+            syslog(LOG_ERR,"Error trying to launch process '%s': %s",id.c_str(),e.what());
+        }
+        _exit(-1);
+    }
+    // parent
+    int rv;
+    if(waitpid(p,&rv,0)<0)
+        throw runtime_error(string(__PRETTY_FUNCTION__)+": failed to waitpid()");
+}
+
+void process::do_notify(const string& id,const string& event,const string& description,configuration& config) {
+    string the_notify;
+    if(!notify.empty())
+        the_notify=notify;
+    else if(!config.notify.empty())
+        the_notify=config.notify;
+    else
+        return;
+    try {
+        string::size_type colon = the_notify.find(':');
+        if(colon==string::npos)
+            throw runtime_error("invalid notify action specification");
+        string nschema = the_notify.substr(0,colon);
+        string ntarget = the_notify.substr(colon+1);
+        if(nschema=="mailto") {
+            notify_mailto(ntarget,id,event,description,config);
+        }else
+            throw runtime_error("unrecognized notification schema");
+    }catch(exception& e) {
+        syslog(LOG_ERR,"Notification error: %s",e.what());
+    }
+}
+
+void process::notify_mailto(const string& email,const string& id,const string& event,const string& description,configuration& config) {
+    int files[2];
+    if(pipe(files))
+        throw runtime_error("Failed to pipe()");
+    pid_t pid = vfork();
+    if(pid==-1) {
+        close(files[0]);
+        close(files[1]);
+        throw runtime_error("Failed to vfork()");
+    }
+    if(!pid) {
+        // child
+        if(dup2(files[0],0)!=0)
+            _exit(-1);
+        close(1);
+        close(files[0]);
+        close(files[1]);
+        execl("/usr/sbin/sendmail","usr/sbin/sendmail","-i",email.c_str(),NULL);
+        _exit(-1);
+    }
+    // parent
+    close(files[0]);
+    FILE *mta = fdopen(files[1],"w");
+    for(headers_t::const_iterator i=mailto_headers.begin();i!=mailto_headers.end();++i) {
+        fprintf(mta,"%s: %s\n",i->first.c_str(),i->second.c_str());
+    }
+    for(headers_t::const_iterator i=config.mailto_headers.begin();i!=config.mailto_headers.end();++i) {
+        if(mailto_headers.find(i->first)!=mailto_headers.end())
+            continue;
+        fprintf(mta,"%s: %s\n",i->first.c_str(),i->second.c_str());
+    }
+    fprintf(mta,
+            "Subject: [%s] %s\n\n"
+            "%s\n"
+            "---\n"
+            "This message was sent automatically by the 'dudki' daemon\n",
+            id.c_str(), event.c_str(),
+            description.c_str() );
+    fclose(mta);
+    int status;
+    waitpid(pid,&status,0);
+    // TODO: check the return code
+}
diff --git a/src/process.h b/src/process.h
new file mode 100644
index 0000000..b6d7091
--- a/dev/null
+++ b/src/process.h
@@ -0,0 +1,36 @@
+#ifndef __PROCESS_H
+#define __PROCESS_H
+
+#include <string>
+#include <map>
+using namespace std;
+
+class configuration;
+
+typedef map<string,string> headers_t;
+
+class process {
+    public:
+        string pidfile;
+        string restart_cmd;
+        string notify;
+        string user;
+        string group;
+        string chroot;
+        headers_t mailto_headers;
+
+        int patience;
+
+        process()
+            : patience(0) { }
+
+        void check(const string& id,configuration& config);
+        void launch(const string& id,configuration& config);
+        void do_notify(const string& id,const string& event,const string& description,configuration& config);
+        void notify_mailto(const string& email,const string& id,const string& event,
+                const string& description,configuration& config);
+};
+
+typedef map<string,process> processes_t;
+
+#endif /* __PROCESS_H */
diff --git a/src/util.cc b/src/util.cc
new file mode 100644
index 0000000..afb2641
--- a/dev/null
+++ b/src/util.cc
@@ -0,0 +1,21 @@
+#include <unistd.h>
+#include <fstream>
+#include <stdexcept>
+using namespace std;
+#include "util.h"
+
+void pid_file::set(const string& f,bool u) {
+    ofstream of(f.c_str(),ios::trunc);
+    if(!of)
+        throw runtime_error(string(__PRETTY_FUNCTION__)+": failed to open file for writing pid");
+    of << getpid() << endl;
+    of.close();
+    file_name = f;
+    unlink_pid = u;
+}
+void pid_file::unlink() {
+    if(!unlink_pid)
+        return;
+    ::unlink(file_name.c_str());
+}
+
diff --git a/src/util.h b/src/util.h
new file mode 100644
index 0000000..314d8e2
--- a/dev/null
+++ b/src/util.h
@@ -0,0 +1,20 @@
+#ifndef __UTIL_H
+#define __UTIL_H
+
+#include <string>
+using namespace std;
+
+class pid_file {
+    public:
+        string file_name;
+        bool unlink_pid;
+
+        pid_file()
+            : unlink_pid(false) { }
+        ~pid_file() { unlink(); }
+
+        void set(const string& f,bool u=true);
+        void unlink();
+};
+
+#endif /* __UTIL_H */