1 files changed, 51 insertions, 0 deletions
diff --git a/src/cmd/fossil/epoch.c b/src/cmd/fossil/epoch.c
new file mode 100644
index 00000000..6aa73bbf
--- /dev/null
+++ b/src/cmd/fossil/epoch.c
@@ -0,0 +1,51 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+uchar buf[65536];
+
+void
+usage(void)
+{
+	fprint(2, "usage: fossil/epoch fs [new-low-epoch]\n");
+	exits("usage");
+}
+
+void
+main(int argc, char **argv)
+{
+	int fd;
+	Header h;
+	Super s;
+
+	ARGBEGIN{
+	default:
+		usage();
+	}ARGEND
+
+	if(argc == 0 || argc > 2)
+		usage();
+
+	if((fd = open(argv[0], argc==2 ? ORDWR : OREAD)) < 0)
+		sysfatal("open %s: %r", argv[0]);
+
+	if(pread(fd, buf, HeaderSize, HeaderOffset) != HeaderSize)
+		sysfatal("reading header: %r");
+	if(!headerUnpack(&h, buf))
+		sysfatal("unpacking header: %r");
+
+	if(pread(fd, buf, h.blockSize, (vlong)h.super*h.blockSize) != h.blockSize)
+		sysfatal("reading super block: %r");
+
+	if(!superUnpack(&s, buf))
+		sysfatal("unpacking super block: %r");
+
+	print("epoch %d\n", s.epochLow);
+	if(argc == 2){
+		s.epochLow = strtoul(argv[1], 0, 0);
+		superPack(&s, buf);
+		if(pwrite(fd, buf, h.blockSize, (vlong)h.super*h.blockSize) != h.blockSize)
+			sysfatal("writing super block: %r");
+	}
+	exits(0);
+}