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/*
* daemon for version information of embedded systems
*
* Copyright (C) 2010 Waldemar Brodkorb <wbx@openadk.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 <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <netinet/in.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>
#define VERSION "0.1"
#define LOGFILE "/tmp/uvd.log"
#define LOCKFILE "/tmp/uvd.lock"
#define BUFSIZE 1024
#define VERFILE "/etc/adkversion"
void version() {
fprintf(stdout, "uvd version %s", VERSION);
exit(EXIT_SUCCESS);
}
static const char *log_date(void) {
static char buf[18];
time_t t = time(NULL);
strftime(buf, 18, "%b %d %H:%M:%S", localtime(&t));
return buf;
}
void die(const char *msg) {
fprintf(stderr, "%s\n", msg);
exit(EXIT_FAILURE);
}
void die_log(FILE *lf, const char *msg) {
fprintf(lf, "%s: %s\n", log_date(), msg);
exit(EXIT_FAILURE);
}
void log_msg(FILE *lf, const char *msg) {
fprintf(lf, "%s: %s\n", log_date(), msg);
fflush(lf);
}
void signal_handler(int sig) {
switch(sig) {
case SIGHUP:
break;
case SIGTERM:
case SIGINT:
case SIGQUIT:
unlink(LOCKFILE);
exit(EXIT_SUCCESS);
break;
default:
break;
}
}
void usage(int argc, char *argv[]) {
if (argc >=1) {
fprintf(stdout, "Usage: %s [ --help | --debug | --version ]\n", argv[0]);
fprintf(stdout, " Options:\n");
fprintf(stdout, " --debug | -d start in debug mode, don't fork\n");
fprintf(stdout, " --version | -v show version\n");
fprintf(stdout, " --help | -h show help\n");
fprintf(stdout, "\n");
}
exit(EXIT_SUCCESS);
}
int main(int argc, char **argv) {
pid_t pid, sid;
int lfd, c, ss, n, res;
FILE *lf = NULL;
int vf;
struct sigaction sigact;
int daemonize = 1;
int optval = 1;
char buf[BUFSIZE];
struct sockaddr_in server = { 0 };
struct sockaddr_in clientaddr; /* client addr */
socklen_t clientlen;
/* options descriptor */
static struct option longopts[] = {
{ "debug", no_argument, 0, 'd' },
{ "help", no_argument, 0, 'h' },
{ "version", no_argument, 0, 'v' },
{ NULL, 0, NULL, 0 }
};
while((c = getopt_long(argc, argv, "dhv", longopts, NULL)) != -1) {
switch(c) {
case 'h':
usage(argc, argv);
break;
case 'v':
version();
break;
case 'd':
daemonize = 0;
break;
default:
usage(argc, argv);
}
}
if (daemonize) {
/* Fork off the parent process */
pid = fork();
if (pid < 0)
die("Can't fork process");
/* If we got a pid, we exit the parent process */
if (pid > 0)
exit(EXIT_SUCCESS);
/* Change the file mode mask */
umask(0);
}
/* Open a logfile */
lf = fopen(LOGFILE, "a");
if (lf == NULL)
die("Can't open logfile");
if (daemonize) {
/* Create a new session for child process */
if ((sid = setsid()) < 0);
die_log(lf, "Can't create a new session for child process");
/* Change the current working directory */
if ((chdir("/")) < 0)
die_log(lf, "Can't change working directory to /");
}
/* check if daemon already running */
if ((lfd = open(LOCKFILE, O_RDWR | O_CREAT, 0640) < 0))
die("Can't open or create lock file");
if (lockf(lfd, F_TLOCK, 0) == -1)
die("uvd already running!");
if (daemonize) {
/* Close out the standard file descriptors */
close(STDIN_FILENO);
close(STDOUT_FILENO);
close(STDERR_FILENO);
}
/* Handle some signals */
sigact.sa_handler = signal_handler;
sigact.sa_flags = 0;
sigaction(SIGHUP, &sigact, NULL);
sigaction(SIGTERM, &sigact, NULL);
sigaction(SIGINT, &sigact, NULL);
sigaction(SIGQUIT, &sigact, NULL);
log_msg(lf, "uvd started successfully");
/* create network socket */
if ((ss = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1)
die("can not create socket");
server.sin_addr.s_addr=htonl(INADDR_ANY);
server.sin_family = AF_INET;
server.sin_port = htons(4242);
if (setsockopt (ss, SOL_SOCKET, SO_BROADCAST, (caddr_t) &optval, sizeof (optval)) < 0)
die("can not set socket option");
if (setsockopt (ss, SOL_SOCKET, SO_REUSEADDR, (caddr_t) &optval, sizeof (optval)) < 0)
die("can not set socket option");
if (bind(ss, (struct sockaddr *) &server, sizeof(server)) < 0)
die("can not bind socket");
/* loop forever */
while(1) {
clientlen = sizeof(clientaddr);
n = recvfrom(ss, buf, BUFSIZE , 0, (struct sockaddr *)&clientaddr, &clientlen);
if (n < 0)
die_log(lf, "error reading from client");
buf[n] = 0;
res = strncmp(buf, "version", n);
if (res > 0) {
log_msg(lf, "been asked for version information");
if ((vf = open(VERFILE, O_RDONLY)) < 0)
die_log(lf, "unable to open version file");
ssize_t num;
do {
num = read(vf, &buf, sizeof(buf));
buf[num] = '\0';
if (sendto(ss, buf, num, 0, (struct sockaddr *) &clientaddr, sizeof(clientaddr)) < 0)
die_log(lf, "can not send data");
} while (num > 0);
close(vf);
}
}
close(ss);
return(0);
}
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