1 files changed, 102 insertions, 0 deletions
diff --git a/src/cmd/ntpfs.c b/src/cmd/ntpfs.c
new file mode 100644
index 0000000..783b56e
--- /dev/null
+++ b/src/cmd/ntpfs.c
@@ -0,0 +1,102 @@
+#include <camellia.h>
+#include <camellia/flags.h>
+#include <camellia/fs/misc.h>
+#include <camellia/fsutil.h>
+#include <camellia/syscalls.h>
+#include <err.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <unistd.h>
+
+// TODO put that in the libc somewhere
+#include "netstack/util.h"
+
+enum {
+	PacketSize = 12 * 4, /* 12 words */
+	ClientMode = 3,
+	NtpV4 = 4 << 3,
+	TxTimestamp = 40,
+};
+
+uint64_t offset = 0;
+
+uint64_t
+getntptime(const char *addr)
+{
+	char packet[PacketSize] = {0};
+	packet[0] |= ClientMode;
+	packet[0] |= NtpV4;
+
+	hid_t h = camellia_open(addr, OPEN_READ | OPEN_WRITE);
+	if (h < 0) {
+		warn("open %s", addr);
+		return 0;
+	}
+	if (write(h, packet, PacketSize) != PacketSize) {
+		warnx("partial write");
+		close(h);
+		return 0;
+	}
+	ssize_t ret = read(h, packet, PacketSize);
+	if (ret != PacketSize) {
+		warnx("partial read");
+		close(h);
+		return 0;
+	}
+
+	return nget64(packet + TxTimestamp);
+}
+
+/* Converts an NTP timestamp to the amount of nanoseconds (10^-9) since the
+ * Unix epoch. */
+uint64_t
+ntp2unix(uint64_t ntp)
+{
+	uint64_t seconds = (ntp >> 32) - 2208988800;
+	uint64_t frac = ntp & 0xFFFFFFFF;
+	uint64_t prec = 1000000000;
+	return seconds * prec + ((frac * prec) >> 32);
+}
+
+int
+main(int argc, const char *argv[])
+{
+	if (argc != 2) {
+		errx(1, "bad usage");
+	}
+
+	// TODO: error checking, once i actually implement timeouts
+	uint64_t ntpt = getntptime(argv[1]);
+	uint64_t unixt = ntp2unix(ntpt);
+	offset = unixt - _sys_time(0);
+
+	char buf[256];
+	int len;
+
+	struct ufs_request req;
+	hid_t reqh;
+	while ((reqh = ufs_wait(buf, sizeof(buf), &req))) {
+		switch (req.op) {
+		case VFSOP_OPEN:
+			if (req.len == 0 && !OPEN_WRITEABLE(req.flags)) {
+				_sys_fs_respond(reqh, NULL, 0, 0);
+			} else {
+				_sys_fs_respond(reqh, NULL, -EGENERIC, 0);
+			}
+			break;
+		case VFSOP_READ:
+			len = snprintf(buf, sizeof(buf), "%lu\n", _sys_time(0) + offset);
+			if (0 <= len && len < (int)sizeof(buf)) {
+				fs_normslice(&req.offset, &req.len, len, false);
+				_sys_fs_respond(reqh, buf + req.offset, req.len, 0);
+			} else {
+				_sys_fs_respond(reqh, NULL, -EGENERIC, 0);
+			}
+			break;
+		default:
+			_sys_fs_respond(reqh, NULL, -ENOSYS, 0);
+			break;
+		}
+	}
+}