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-rw-r--r--daemon.h173
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diff --git a/daemon.h b/daemon.h
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+++ b/daemon.h
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+/*
+ * uAnytun
+ *
+ * uAnytun is a tiny implementation of SATP. Unlike Anytun which is a full
+ * featured implementation uAnytun has no support for multiple connections
+ * or synchronisation. It is a small single threaded implementation intended
+ * to act as a client on small platforms.
+ * The secure anycast tunneling protocol (satp) defines a protocol used
+ * for communication between any combination of unicast and anycast
+ * tunnel endpoints. It has less protocol overhead than IPSec in Tunnel
+ * mode and allows tunneling of every ETHER TYPE protocol (e.g.
+ * ethernet, ip, arp ...). satp directly includes cryptography and
+ * message authentication based on the methodes used by SRTP. It is
+ * intended to deliver a generic, scaleable and secure solution for
+ * tunneling and relaying of packets of any protocol.
+ *
+ *
+ * Copyright (C) 2007-2008 Christian Pointner <equinox@anytun.org>
+ *
+ * This file is part of uAnytun.
+ *
+ * uAnytun 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 3 of the License, or
+ * any later version.
+ *
+ * uAnytun 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 uAnytun. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _DAEMON_H_
+#define _DAEMON_H_
+
+#include <poll.h>
+#include <fcntl.h>
+#include <pwd.h>
+#include <grp.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+struct priv_info_struct {
+ struct passwd* pw_;
+ struct group* gr_;
+};
+typedef struct priv_info_struct priv_info_t;
+
+int priv_init(priv_info_t* priv, const char* username, const char* groupname)
+{
+ if(!priv)
+ return -1;
+
+ priv->pw_ = NULL;
+ priv->gr_ = NULL;
+
+ priv->pw_ = getpwnam(username);
+ if(!priv->pw_) {
+ log_printf(ERROR, "unkown user %s", username);
+ return -1;
+ }
+
+ if(groupname)
+ priv->gr_ = getgrnam(groupname);
+ else
+ priv->gr_ = getgrgid(priv->pw_->pw_gid);
+
+ if(!priv->gr_) {
+ log_printf(ERROR, "unkown group %s", groupname);
+ return -1;
+ }
+
+ return 0;
+}
+
+int priv_drop(priv_info_t* priv)
+{
+ if(!priv || !priv->pw_ || !priv->gr_) {
+ log_printf(ERROR, "privileges not initialized properly");
+ return -1;
+ }
+
+ if(setgid(priv->gr_->gr_gid)) {
+ log_printf(ERROR, "setgid('%s') failed: %s", priv->gr_->gr_name, strerror(errno));
+ return -1;
+ }
+
+ gid_t gr_list[1];
+ gr_list[0] = priv->gr_->gr_gid;
+ if(setgroups (1, gr_list)) {
+ log_printf(ERROR, "setgroups(['%s']) failed: %s", priv->gr_->gr_name, strerror(errno));
+ return -1;
+ }
+
+ if(setuid(priv->pw_->pw_uid)) {
+ log_printf(ERROR, "setuid('%s') failed: %s", priv->pw_->pw_name, strerror(errno));
+ return -1;
+ }
+
+ log_printf(NOTICE, "dropped privileges to %s:%s", priv->pw_->pw_name, priv->gr_->gr_name);
+ return 0;
+}
+
+
+int do_chroot(const char* chrootdir)
+{
+ if(getuid() != 0) {
+ log_printf(ERROR, "this programm has to be run as root in order to run in a chroot");
+ return -1;
+ }
+
+ if(chroot(chrootdir)) {
+ log_printf(ERROR, "can't chroot to %s: %s", chrootdir, strerror(errno));
+ return -1;
+ }
+ log_printf(NOTICE, "we are in chroot jail (%s) now", chrootdir);
+ if(chdir("/")) {
+ log_printf(ERROR, "can't change to /: %s", strerror(errno));
+ return -1;
+ }
+}
+
+void daemonize()
+{
+ pid_t pid;
+
+ pid = fork();
+ if(pid < 0) {
+ log_printf(ERROR, "daemonizing failed at fork(): %s, exitting", strerror(errno));
+ exit(-1);
+ }
+ if(pid) exit(0);
+
+ umask(0);
+
+ if(setsid() < 0) {
+ log_printf(ERROR, "daemonizing failed at setsid(): %s, exitting", strerror(errno));
+ exit(-1);
+ }
+
+ pid = fork();
+ if(pid < 0) {
+ log_printf(ERROR, "daemonizing failed at fork(): %s, exitting", strerror(errno));
+ exit(-1);
+ }
+ if(pid) exit(0);
+
+ if ((chdir("/")) < 0) {
+ log_printf(ERROR, "daemonizing failed at chdir(): %s, exitting", strerror(errno));
+ exit(-1);
+ }
+
+ int fd;
+ for (fd=0;fd<=2;fd++) // close all file descriptors
+ close(fd);
+ fd = open("/dev/null",O_RDWR); // stdin
+ if(fd == -1)
+ log_printf(WARNING, "can't open stdin (chroot and no link to /dev/null?)");
+ else {
+ if(dup(fd) == -1) // stdout
+ log_printf(WARNING, "can't open stdout");
+ if(dup(fd) == -1) // stderr
+ log_printf(WARNING, "can't open stderr");
+ }
+ umask(027);
+}
+
+#endif
+