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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/***************************************************************************
* daemon.cc
*
* Thu Jun 9 10:27:59 CEST 2005
* Copyright 2005 Bent Bisballe
* deva@aasimon.org
****************************************************************************/
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "daemon.h"
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
// For getgrent and getgrent
#include <sys/types.h>
#include <grp.h>
#include <pwd.h>
// For strcmp
#include <string.h>
Daemon::Daemon()
{}
Daemon::~Daemon()
{}
int Daemon::run(const char *user, const char* group, bool foreground)
{
int f;
int fd;
// Fetch user id
int uid = -1;
struct passwd *p = getpwent();
while(p) {
if(strcmp(p->pw_name, user) == 0) uid = p->pw_uid;
p = getpwent();
}
if(uid == -1) {
fprintf(stderr, "Could not find user \"%s\" in /etc/passwd file.\n", user);
}
// Fetch group id
int gid = -1;
struct group *g = getgrent();
while(g) {
if(strcmp(g->gr_name, group) == 0) gid = g->gr_gid;
g = getgrent();
}
if(gid == -1) {
fprintf(stderr, "Could not find group \"%s\" in /etc/group file.\n", group);
}
if(chdir("/") == -1) fprintf(stderr, "Could not chdir to '/'.\n");
umask(0);
if(!foreground) {
f = fork();
switch(f) {
case -1: // Fork error
perror("Fork in daemon.cc");
return 1;
case 0: // Forked child
break;
default: // Parent
return 0;
}
}
// Switch to given group
if(setgid(gid) != 0) {
fprintf(stderr, "Failed to change to group \"%s\" (gid: %d), quitting.\n", group, gid);
perror("");
fprintf(stderr, "Runnning daemon as current group\n");
}
// Switch to given user
if(setuid(uid) != 0) {
fprintf(stderr, "Failed to change to user \"%s\" (uid: %d), quitting.\n", user, uid);
perror("");
fprintf(stderr, "Runnning daemon as current user\n");
}
// Redirect stdin, stdout and stderr to /dev/null
fd = open("/dev/null", O_NOCTTY | O_RDWR, 0666);
dup2(0, fd);
dup2(1, fd);
dup2(2, fd);
setsid();
signal (SIGTERM, SIG_IGN);
if(!foreground) signal (SIGINT, SIG_IGN);
signal (SIGHUP, SIG_IGN);
return daemon_main();
}
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