Flatten the qarsh tree.

1 files changed, 271 insertions, 0 deletions

diff --git a/btimed.c b/btimed.c
new file mode 100644
index 0000000..259c8aa
--- /dev/null
+++ b/btimed.c
@@ -0,0 +1,271 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
+#include <unistd.h>
+#include <errno.h>
+#include <signal.h>
+#include <syslog.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include "btime_int.h"
+
+static void (*btimed_error)(int level, const char *fmt, ...);
+
+static void btimed(void);
+static unsigned int get_btime(void);
+static int daemon_init(void);
+static void btimed_perror(int level, const char *fmt, ...);
+static void sigchld_hdlr(int sig);
+static void usage(const char *progname);
+
+
+int
+main(int argc, char **argv)
+{
+	struct sigaction sa;
+	int debug = 0;
+	int c;
+
+	while ((c = getopt(argc, argv, "hd")) != -1) {
+		switch (c)  {
+			case 'd':
+				debug = 1;
+				break;
+			case 'h':
+			case '?':
+			default:
+				usage(argv[0]);
+				exit(2);
+		}
+	}
+
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_handler = sigchld_hdlr;
+	sigemptyset(&sa.sa_mask);
+	sa.sa_flags = SA_NOCLDSTOP | SA_RESTART; 
+	sigaction(SIGCHLD, &sa, NULL); 
+
+	if (debug) {
+		btimed_error = btimed_perror;
+	} else {
+		btimed_error = syslog;	
+		daemon_init();
+	}
+
+	btimed();
+
+	return 0;
+}
+
+
+/*
+ *---------------------------------------------------------------------------
+ *
+ * btimed --
+ *
+ *	The main loop of the deamon.  It listens on its well know port for
+ * messages, responds to the request via a child process.
+ *
+ * Returns:
+ *	Never returns.
+ *
+ * Side effects:
+ *	Child processes are created.
+ *---------------------------------------------------------------------------
+ */
+
+static void
+btimed(void)
+{
+	int sd;
+	char msg[BTIME_MSGLEN];
+	struct sockaddr_in cli_addr;
+	int cli_addr_len;
+	struct sockaddr_in my_addr;
+	pid_t pid;
+	ssize_t nbytes;
+
+	if ((sd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
+		btimed_error(LOG_ERR, "Could not create socket: %s\n", 
+		        strerror(errno));
+		exit(1);
+	}
+
+	memset(&my_addr, 0, sizeof my_addr);
+	my_addr.sin_family = AF_INET;
+	my_addr.sin_addr.s_addr = htonl(INADDR_ANY);
+	my_addr.sin_port = htons(BTIME_PORT);
+	if (bind(sd, (struct sockaddr *)&my_addr, sizeof my_addr) < 0) {
+		btimed_error(LOG_ERR, "Could not bind to local address: %s\n", 
+		        strerror(errno));
+		exit(1);
+	}
+
+	for (;;) {	
+		memset(&cli_addr, 0, sizeof cli_addr);
+		cli_addr_len = sizeof cli_addr;
+		nbytes = recvfrom(sd, &msg, BTIME_MSGLEN, MSG_WAITALL, 
+		         (struct sockaddr *)&cli_addr, &cli_addr_len);
+
+		if ((pid = fork()) < 0) {	
+			btimed_error(LOG_ERR, "Could not fork(): %s\n", strerror(errno));
+			exit(1);
+		}
+
+		if (pid == 0) {
+			memset(msg, 0, BTIME_MSGLEN);
+			sprintf(msg, "%u\n", get_btime());
+			sendto(sd, &msg, BTIME_MSGLEN, MSG_DONTWAIT, 
+			       (struct sockaddr *)&cli_addr, cli_addr_len);
+
+			exit(0);
+		}
+	}
+
+	close(sd);
+}
+
+
+
+/*
+ *---------------------------------------------------------------------------
+ *
+ * get_btime --
+ *
+ *	Return machine's boot time.
+ *
+ * Returns:
+ *	0 on failure
+ * 	non-zero on success.
+ *
+ *---------------------------------------------------------------------------
+ */
+
+static unsigned int 
+get_btime(void)
+{
+	FILE *statf;
+	char line[1024];
+	unsigned int btime = 0;
+
+	if ((statf = fopen("/proc/stat", "r")) == NULL) {
+		btimed_error(LOG_ERR, "/proc/stat open failure: %s\n", 
+		        strerror(errno));
+		exit(1);
+	}
+
+	while (fgets(line, 1024, statf) != NULL) {
+		if (strstr(line, "btime") != NULL) {
+			sscanf(line, "%*s%u", &btime); 
+		}
+			
+	}
+
+	fclose(statf);
+
+	return btime;
+}
+
+
+/*
+ *---------------------------------------------------------------------------
+ *
+ * daemon_init --
+ *
+ *	Set up a basic daemon environment
+ *
+ * Returns:
+ *	0 on success
+ * non-zero on failure.
+ *
+ * Side effects:
+ *	All fds are closed and process is now a session leader.
+ *
+ *---------------------------------------------------------------------------
+ */
+
+static int 
+daemon_init(void)
+{
+	pid_t pid;
+	int fd;
+	int maxfd = sysconf(_SC_OPEN_MAX);
+	
+	if ((pid = fork()) < 0) {
+		return(-1);
+	} else if (pid != 0) {
+		exit(0);	/* Exit in parent */
+	}
+
+	/* 
+	 * Child sets up daemon environment 
+	 */
+
+	setsid();	/* Become session leader */
+	chdir("/");
+	umask(0);
+	for (fd = 0; fd < maxfd; fd++) {
+		close(fd);
+	}
+	errno = 0;	/* probably set to EBADFD from above loop, reset */
+
+	openlog("btimed", LOG_PID, LOG_USER);
+
+	return 0;
+}
+
+
+/*
+ *---------------------------------------------------------------------------
+ *
+ * btimed_perror --
+ *
+ * 	Print error messages to stderr, level is not used, it is there
+ * 	to have the same calling args as syslog(3) so we can use either
+ *	based on debug level.
+ *
+ * Returns:
+ *  NA
+ *
+ * Side effects:
+ * 	None 
+ *---------------------------------------------------------------------------
+ */
+
+static void 
+btimed_perror(int level, const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	vfprintf(stderr, fmt, ap);
+	va_end(ap);
+}
+
+
+static void 
+sigchld_hdlr(int sig)
+{
+	int status;
+
+	wait(&status);
+	return;
+}
+
+
+static void 
+usage(const char *progname)
+{
+	fprintf(stderr, "Usage: %s [OPTION]...\n"
+	        "-h\tPrint this help and exit.\n"
+	        "-d\tDon't daemonize, send output to stderr.\n",
+	        progname);
+
+	return;
+}