1 files changed, 111 insertions, 0 deletions
diff --git a/btime.c b/btime.c
new file mode 100644
index 0000000..f22c08b
--- /dev/null
+++ b/btime.c
@@ -0,0 +1,111 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <netdb.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include "btime_int.h"
+
+/*
+ * btime --
+ * 
+ *	Return the boot time of a remote host if that host is running the
+ *	btimed deamon.
+ *
+ * Returns:
+ *	btime, or 0 on failure.
+ */
+
+unsigned int
+btime(const char *host)
+{
+	int sd;
+	char msg[BTIME_MSGLEN];
+	struct sockaddr_in serv_addr;
+	struct sockaddr_in my_addr;
+	int serv_addr_len;
+	struct hostent *hostent;
+	in_addr_t inaddr;
+	unsigned int btime;
+	ssize_t nbytes;	
+	int retry;
+
+	if ((sd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
+		fprintf(stderr, "Could not create socket: %s\n", 
+		        strerror(errno));
+		return 0;
+	}
+
+	memset(&serv_addr, 0, sizeof serv_addr);
+	serv_addr.sin_family = AF_INET;
+	serv_addr.sin_port = htons(BTIME_PORT);
+
+	if ((inaddr = inet_addr(host)) != INADDR_NONE) {
+		memcpy(&serv_addr.sin_addr, &inaddr, sizeof inaddr);
+	} else {
+		if ((hostent = gethostbyname(host)) == NULL) {
+			return 0;
+		}
+
+		memcpy(&serv_addr.sin_addr, hostent->h_addr, hostent->h_length);
+	}
+
+	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(0);
+	if (bind(sd, (struct sockaddr *)&my_addr, sizeof my_addr) < 0) {
+		fprintf(stderr, "Could not bind to local address: %s\n", 
+		        strerror(errno));
+		return 0;
+	}
+
+	memset(msg, 0, BTIME_MSGLEN);
+	for (retry = 0; retry < MAX_RETRY; retry++) {
+		serv_addr_len = sizeof serv_addr;
+		if ((nbytes = sendto(sd, &msg, BTIME_MSGLEN, MSG_DONTWAIT,
+	       	 (struct sockaddr *)&serv_addr, serv_addr_len)) < 0) {
+			if (errno == EAGAIN) {
+				usleep(retry * 100);
+			} else {
+				/* Non EAGAIN error... */
+				break;
+			}
+		} else {
+			break;
+		}
+	}
+	
+
+	memset(msg, 0, BTIME_MSGLEN);
+	for (retry = 0; retry < MAX_RETRY; retry++) {
+		serv_addr_len = sizeof serv_addr;
+		if ((nbytes = recvfrom(sd, &msg, BTIME_MSGLEN, MSG_DONTWAIT, 
+	         (struct sockaddr *)&serv_addr, &serv_addr_len)) < 0) {
+			if (errno == EAGAIN) {
+				usleep(retry * 100);
+			} else {
+				/* Non EAGAIN error... */
+				break;
+			}
+		} else {
+			break;
+		}
+	}
+
+	if (nbytes == 0) {
+		btime = 0;
+	} else {
+		btime = strtoul(msg, (char **)NULL, 10);
+	}
+
+	close(sd);
+
+	return btime;
+}