C/c++ deamon

hello:

Je tente de me faire un deamon avec une lib
don voici l’exemple que j’ai casiment repris mai mis dans une class. evidament sa bug…
vu le message de compilation je necomprend rien aux plantage.

0pointer.de/lennart/projects/lib … index.html

fichier *.h
#ifndef DEF_ME_DEMON
#define DEF_ME_DEMON


class c_deamon
{
	public:
		c_deamon();
		void start_in_daemon();
};
#endif //fin des macro

/***
  This file is part of libdaemon.

  Copyright 2003-2008 Lennart Poettering

  libdaemon is free software; you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License as
  published by the Free Software Foundation, either version 2.1 of the
  License, or (at your option) any later version.

  libdaemon is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with libdaemon. If not, see
  <http://www.gnu.org/licenses/>.
***/

#include <signal.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/unistd.h>
#include <sys/select.h>

#include <libdaemon/dfork.h>
#include <libdaemon/dsignal.h>
#include <libdaemon/dlog.h>
#include <libdaemon/dpid.h>
#include <libdaemon/dexec.h>
#include "c_daemon.h"
c_deamon::c_deamon(){}

void c_deamon::start_in_daemon()
{
   pid_t pid;

    /* Reset signal handlers */
    if (daemon_reset_sigs(-1) < 0) {
        daemon_log(LOG_ERR, "Failed to reset all signal handlers: %s", strerror(errno));
        return ;
    }

    /* Unblock signals */
    if (daemon_unblock_sigs(-1) < 0) {
        daemon_log(LOG_ERR, "Failed to unblock all signals: %s", strerror(errno));
        return ;
    }

int argc;
char *argv[255];
    /* Set indetification string for the daemon for both syslog and PID file */
    daemon_pid_file_ident = daemon_log_ident = daemon_ident_from_argv0(argv[0]);

    /* Check if we are called with -k parameter */
    if (argc >= 2 && !strcmp(argv[1], "-k")) {
        int ret;

        /* Kill daemon with SIGTERM */

        /* Check if the new function daemon_pid_file_kill_wait() is available, if it is, use it. */
        if ((ret = daemon_pid_file_kill_wait(SIGTERM, 5)) < 0)
            daemon_log(LOG_WARNING, "Failed to kill daemon: %s", strerror(errno));

        return ;//ret < 0 ? 1 : 0;
    }

    /* Check that the daemon is not rung twice a the same time */
    if ((pid = daemon_pid_file_is_running()) >= 0) {
        daemon_log(LOG_ERR, "Daemon already running on PID file %u", pid);
        return ;
    }

    /* Prepare for return value passing from the initialization procedure of the daemon process */
    if (daemon_retval_init() < 0) {
        daemon_log(LOG_ERR, "Failed to create pipe.");
        return ;
    }

    /* Do the fork */
    if ((pid = daemon_fork()) < 0) {

        /* Exit on error */
        daemon_retval_done();
        return ;

    } else if (pid) { /* The parent */
        int ret;

        /* Wait for 20 seconds for the return value passed from the daemon process */
        if ((ret = daemon_retval_wait(20)) < 0) {
            daemon_log(LOG_ERR, "Could not recieve return value from daemon process: %s", strerror(errno));
            return ;
        }

        daemon_log(ret != 0 ? LOG_ERR : LOG_INFO, "Daemon returned %i as return value.", ret);
        return ;//ret;

    } else { /* The daemon */
        int fd, quit = 0;
        fd_set fds;

        /* Close FDs */
        if (daemon_close_all(-1) < 0) {
            daemon_log(LOG_ERR, "Failed to close all file descriptors: %s", strerror(errno));

            /* Send the error condition to the parent process */
            daemon_retval_send(1);
            goto finish;
        }

        /* Create the PID file */
        if (daemon_pid_file_create() < 0) {
            daemon_log(LOG_ERR, "Could not create PID file (%s).", strerror(errno));
            daemon_retval_send(2);
            goto finish;
        }

        /* Initialize signal handling */
        if (daemon_signal_init(SIGINT, SIGTERM, SIGQUIT, SIGHUP, 0) < 0) {
            daemon_log(LOG_ERR, "Could not register signal handlers (%s).", strerror(errno));
            daemon_retval_send(3);
            goto finish;
        }

        /*... do some further init work here */


        /* Send OK to parent process */
        daemon_retval_send(0);

        daemon_log(LOG_INFO, "Sucessfully started");

        /* Prepare for select() on the signal fd */
        FD_ZERO(&fds);
        fd = daemon_signal_fd();
        FD_SET(fd, &fds);

        while (!quit) {
            fd_set fds2 = fds;

            /* Wait for an incoming signal */
            if (select(FD_SETSIZE, &fds2, 0, 0, 0) < 0) {

                /* If we've been interrupted by an incoming signal, continue */
                if (errno == EINTR)
                    continue;

                daemon_log(LOG_ERR, "select(): %s", strerror(errno));
                break;
            }

            /* Check if a signal has been recieved */
            if (FD_ISSET(fd, &fds2)) {
                int sig;

                /* Get signal */
                if ((sig = daemon_signal_next()) <= 0) {
                    daemon_log(LOG_ERR, "daemon_signal_next() failed: %s", strerror(errno));
                    break;
                }

                /* Dispatch signal */
                switch (sig) {

                    case SIGINT:
                    case SIGQUIT:
                    case SIGTERM:
                        daemon_log(LOG_WARNING, "Got SIGINT, SIGQUIT or SIGTERM.");
                        quit = 1;
                        break;

                    case SIGHUP:
                        daemon_log(LOG_INFO, "Got a HUP");
                        daemon_exec("/", NULL, "/bin/ls", "ls", (char*) NULL);
                        break;

                }
            }
        }

        /* Do a cleanup */
finish:
        daemon_log(LOG_INFO, "Exiting...");
        daemon_retval_send(255);
        daemon_signal_done();
        daemon_pid_file_remove();

        return ;
    }
}
/*
int main(int argc, char *argv[]) {
 
}

*/

le message d’erreur est le suivant:

[code]/***
This file is part of libdaemon.

Copyright 2003-2008 Lennart Poettering

libdaemon is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation, either version 2.1 of the
License, or (at your option) any later version.

libdaemon is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with libdaemon. If not, see
http://www.gnu.org/licenses/.
***/

#include <signal.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/unistd.h>
#include <sys/select.h>

#include <libdaemon/dfork.h>
#include <libdaemon/dsignal.h>
#include <libdaemon/dlog.h>
#include <libdaemon/dpid.h>
#include <libdaemon/dexec.h>
#include "c_daemon.h"
c_deamon::c_deamon(){}

void c_deamon::start_in_daemon()
{
pid_t pid;

/* Reset signal handlers */
if (daemon_reset_sigs(-1) < 0) {
    daemon_log(LOG_ERR, "Failed to reset all signal handlers: %s", strerror(errno));
    return ;
}

/* Unblock signals */
if (daemon_unblock_sigs(-1) < 0) {
    daemon_log(LOG_ERR, "Failed to unblock all signals: %s", strerror(errno));
    return ;
}

int argc;
char argv[255];
/
Set indetification string for the daemon for both syslog and PID file */
daemon_pid_file_ident = daemon_log_ident = daemon_ident_from_argv0(argv[0]);

/* Check if we are called with -k parameter */
if (argc >= 2 && !strcmp(argv[1], "-k")) {
    int ret;

    /* Kill daemon with SIGTERM */

    /* Check if the new function daemon_pid_file_kill_wait() is available, if it is, use it. */
    if ((ret = daemon_pid_file_kill_wait(SIGTERM, 5)) < 0)
        daemon_log(LOG_WARNING, "Failed to kill daemon: %s", strerror(errno));

    return ;//ret < 0 ? 1 : 0;
}

/* Check that the daemon is not rung twice a the same time */
if ((pid = daemon_pid_file_is_running()) >= 0) {
    daemon_log(LOG_ERR, "Daemon already running on PID file %u", pid);
    return ;
}

/* Prepare for return value passing from the initialization procedure of the daemon process */
if (daemon_retval_init() < 0) {
    daemon_log(LOG_ERR, "Failed to create pipe.");
    return ;
}

/* Do the fork */
if ((pid = daemon_fork()) < 0) {

    /* Exit on error */
    daemon_retval_done();
    return ;

} else if (pid) { /* The parent */
    int ret;

    /* Wait for 20 seconds for the return value passed from the daemon process */
    if ((ret = daemon_retval_wait(20)) < 0) {
        daemon_log(LOG_ERR, "Could not recieve return value from daemon process: %s", strerror(errno));
        return ;
    }

    daemon_log(ret != 0 ? LOG_ERR : LOG_INFO, "Daemon returned %i as return value.", ret);
    return ;//ret;

} else { /* The daemon */
    int fd, quit = 0;
    fd_set fds;

    /* Close FDs */
    if (daemon_close_all(-1) < 0) {
        daemon_log(LOG_ERR, "Failed to close all file descriptors: %s", strerror(errno));

        /* Send the error condition to the parent process */
        daemon_retval_send(1);
        goto finish;
    }

    /* Create the PID file */
    if (daemon_pid_file_create() < 0) {
        daemon_log(LOG_ERR, "Could not create PID file (%s).", strerror(errno));
        daemon_retval_send(2);
        goto finish;
    }

    /* Initialize signal handling */
    if (daemon_signal_init(SIGINT, SIGTERM, SIGQUIT, SIGHUP, 0) < 0) {
        daemon_log(LOG_ERR, "Could not register signal handlers (%s).", strerror(errno));
        daemon_retval_send(3);
        goto finish;
    }

    /*... do some further init work here */


    /* Send OK to parent process */
    daemon_retval_send(0);

    daemon_log(LOG_INFO, "Sucessfully started");

    /* Prepare for select() on the signal fd */
    FD_ZERO(&fds);
    fd = daemon_signal_fd();
    FD_SET(fd, &fds);

    while (!quit) {
        fd_set fds2 = fds;

        /* Wait for an incoming signal */
        if (select(FD_SETSIZE, &fds2, 0, 0, 0) < 0) {

            /* If we've been interrupted by an incoming signal, continue */
            if (errno == EINTR)
                continue;

            daemon_log(LOG_ERR, "select(): %s", strerror(errno));
            break;
        }

        /* Check if a signal has been recieved */
        if (FD_ISSET(fd, &fds2)) {
            int sig;

            /* Get signal */
            if ((sig = daemon_signal_next()) <= 0) {
                daemon_log(LOG_ERR, "daemon_signal_next() failed: %s", strerror(errno));
                break;
            }

            /* Dispatch signal */
            switch (sig) {

                case SIGINT:
                case SIGQUIT:
                case SIGTERM:
                    daemon_log(LOG_WARNING, "Got SIGINT, SIGQUIT or SIGTERM.");
                    quit = 1;
                    break;

                case SIGHUP:
                    daemon_log(LOG_INFO, "Got a HUP");
                    daemon_exec("/", NULL, "/bin/ls", "ls", (char*) NULL);
                    break;

            }
        }
    }

    /* Do a cleanup */

finish:
daemon_log(LOG_INFO, “Exiting…”);
daemon_retval_send(255);
daemon_signal_done();
daemon_pid_file_remove();

    return ;
}

}
/*
int main(int argc, char *argv[]) {

}

*/
[/code]

message d’erreur:

main.o: In function `c_deamon::start_in_daemon()':
main.cpp:(.text+0x4c6): undefined reference to `daemon_reset_sigs'
main.cpp:(.text+0x4f4): undefined reference to `daemon_log'
main.cpp:(.text+0x505): undefined reference to `daemon_unblock_sigs'
main.cpp:(.text+0x533): undefined reference to `daemon_log'
main.cpp:(.text+0x546): undefined reference to `daemon_ident_from_argv0'
main.cpp:(.text+0x54b): undefined reference to `daemon_log_ident'
main.cpp:(.text+0x550): undefined reference to `daemon_log_ident'
main.cpp:(.text+0x555): undefined reference to `daemon_pid_file_ident'
main.cpp:(.text+0x589): undefined reference to `daemon_pid_file_kill_wait'
main.cpp:(.text+0x5c1): undefined reference to `daemon_log'
main.cpp:(.text+0x5cb): undefined reference to `daemon_pid_file_is_running'
main.cpp:(.text+0x5f5): undefined reference to `daemon_log'
main.cpp:(.text+0x5ff): undefined reference to `daemon_retval_init'
main.cpp:(.text+0x61a): undefined reference to `daemon_log'
main.cpp:(.text+0x624): undefined reference to `daemon_fork'
main.cpp:(.text+0x636): undefined reference to `daemon_retval_done'
main.cpp:(.text+0x651): undefined reference to `daemon_retval_wait'
main.cpp:(.text+0x685): undefined reference to `daemon_log'
main.cpp:(.text+0x6c3): undefined reference to `daemon_log'
main.cpp:(.text+0x6db): undefined reference to `daemon_close_all'
main.cpp:(.text+0x709): undefined reference to `daemon_log'
main.cpp:(.text+0x715): undefined reference to `daemon_retval_send'
main.cpp:(.text+0x71f): undefined reference to `daemon_pid_file_create'
main.cpp:(.text+0x74d): undefined reference to `daemon_log'
main.cpp:(.text+0x759): undefined reference to `daemon_retval_send'
main.cpp:(.text+0x78a): undefined reference to `daemon_signal_init'
main.cpp:(.text+0x7b8): undefined reference to `daemon_log'
main.cpp:(.text+0x7c4): undefined reference to `daemon_retval_send'
main.cpp:(.text+0x7d5): undefined reference to `daemon_retval_send'
main.cpp:(.text+0x7e9): undefined reference to `daemon_log'
main.cpp:(.text+0x80d): undefined reference to `daemon_signal_fd'
main.cpp:(.text+0x8cd): undefined reference to `daemon_log'
main.cpp:(.text+0x8fd): undefined reference to `daemon_signal_next'
main.cpp:(.text+0x932): undefined reference to `daemon_log'
main.cpp:(.text+0x97a): undefined reference to `daemon_log'
main.cpp:(.text+0x997): undefined reference to `daemon_log'
main.cpp:(.text+0x9c3): undefined reference to `daemon_exec'
main.cpp:(.text+0x9e1): undefined reference to `daemon_log'
main.cpp:(.text+0x9ed):undefined reference  to `daemon_retval_send'
main.cpp:(.text+0x9f2): undefined reference to `daemon_signal_done'
main.cpp:(.text+0x9f7): undefined reference to `daemon_pid_file_remove'
collect2: ld returned 1 exit status

j’ai simplement enlever les return x; pour faire une methode qui ne renvoie rien . et adapter 2 variable qui son celle du main
int argc et char *argv[]

normalement les erreur undefined reference son déclarée dans la lib (enfin je supose)
so vous avez une idée je suis preneur
Merci d’avance

“undefine reference” c’est un problème de “linkage”. Si tu as put compiler c’est que le compilateur vois les entêtes mais si tu peut pas linker c’est qu’il trouve pas les .o correspondants.

Pourquoi ne pas utiliser l’appel système deamon() ?

[quote=“MisterFreez”]“undefine reference” c’est un problème de “linkage”. Si tu as put compiler c’est que le compilateur vois les entêtes mais si tu peut pas linker c’est qu’il trouve pas les .o correspondants.

[quote]
bizzard vu que c est une source C ,il faudrai que je compile avec gcc et pas g++ ou c’est possible avec g++ ?
jevoit pas trop comment on corrige l’histoire :question:

[quote]
Pourquoi ne pas utiliser l’appel système deamon() ?[/quote][/quote][/quote]
Pas de doc dessus enfin j’ai rien trouver a ce sujet ? google me sort tout le temps des script…

Bref j’avance pas.

Plop on ma soufler la réponse sur irc

il faut linker avec -ldaemon

Merci systemfault insi qu’a MisterFreez

plop
Finalement avec cette lib j’ai des bug . du coup je me suis tourner ver daemon() comme proposée ci dessus évidements autre chose vien poser souci.

est-ce qu’il y a un moyen d’avoir l’équivalent de > /dev/null ?
En effet si l’api C, daemon() est faite et qu’une sortie du type:

Surviens après j’ai quand même ça dans la console & terminal ce qui est indésirable.

si vous avez une piste je suis preneur ?

close(STDIN_FILENO); close(STDOUT_FILENO); close(STDERR_FILENO);non :question:

Si il fait ça il va se manger des erreurs dès qu’il voudra afficher un pauvre warning…
(et si le programme est bien écrit, les erreurs ne passeront pas inaperçues)

Regarde man dup2

Un peu de pseudo-code :

int fd = open(/dev/null, w); fdup2(STDOUT_FILENO, fd); fdup2(STDERR_FILENO, fd); close(fd);

Comme ça stdout et stderr ne pointeront plus vers le terminal mais vers /dev/null.
Les desrcripteurs de fichier auparavant associés à stdout et stderr sont fermés par dup2.
Le close n’est pas nécessaire, c’est juste des économies de bout de chandelles.

[quote=“BBT1”]Regarde man dup2

Un peu de pseudo-code :

int fd = open(/dev/null, w); fdup2(STDOUT_FILENO, fd); fdup2(STDERR_FILENO, fd); close(fd);

Comme ça stdout et stderr ne pointeront plus vers le terminal mais vers /dev/null.
Les desrcripteurs de fichier auparavant associés à stdout et stderr sont fermés par dup2.
Le close n’est pas nécessaire, c’est juste des économies de bout de chandelles.[/quote]

Merci sa tourne :slightly_smiling:
Note voila ce que j’ai fait:

void c_daemon::start_deamon()
{
	int w = 0,x = 0,z = 0,fd = 0;
	daemon(x,z); 
	fd = open("/dev/null", w);
	dup2(STDOUT_FILENO, fd);
	dup2(STDERR_FILENO, fd);
	close(fd);
}

la variable z pourrait d’après le man re-diriger ver /dev/null mai vu que c’ est pas modifiable…

[quote=“panthere”] void c_daemon::start_deamon() { int w = 0,x = 0,z = 0,fd = 0; daemon(x,z); fd = open("/dev/null", w); dup2(STDOUT_FILENO, fd); dup2(STDERR_FILENO, fd); close(fd); } [/quote]

Bon, c’est vrai ce qu’on fait c’est pareil que le “noclose” de daemon,
mais là tu n’auras pas grand chose à changer si tu veux rediriger les sorties sur un fichier de log.
Par contre, il faut quand même ouvrir /dev/null en écriture avec les bons flags (par exemple O_WRONLY)
et tester les codes de retour de toutes ces fonctions.