add a small udp based daemon

1 files changed, 237 insertions, 0 deletions

diff --git a/package/uvd/src/uvd.c b/package/uvd/src/uvd.c
new file mode 100644
index 000000000..f41a5c885
--- /dev/null
+++ b/package/uvd/src/uvd.c
@@ -0,0 +1,237 @@
+/*
+ * 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);
+}