fossil: import from plan 9

R=rsc
https://codereview.appspot.com/7988047

src/cmd/fossil/dump.c

@@ -0,0 +1,86 @@
+/*
+ * Clumsy hack to take snapshots and dumps.
+ */
+#include <u.h>
+#include <libc.h>
+
+void
+usage(void)
+{
+	fprint(2, "usage: fossil/dump [-i snap-interval] [-n name] fscons /n/fossil\n");
+	exits("usage");
+}
+
+char*
+snapnow(void)
+{
+	Tm t;
+	static char buf[100];
+
+	t = *localtime(time(0)-5*60*60);	/* take dumps at 5:00 am */
+
+	sprint(buf, "archive/%d/%02d%02d", t.year+1900, t.mon+1, t.mday);
+	return buf;
+}
+
+void
+main(int argc, char **argv)
+{
+	int onlyarchive, cons, s;
+	ulong t, i;
+	char *name;
+
+	name = "main";
+	s = 0;
+	onlyarchive = 0;
+	i = 60*60;		/* one hour */
+	ARGBEGIN{
+	case 'i':
+		i = atoi(EARGF(usage()));
+		if(i == 0){
+			onlyarchive = 1;
+			i = 60*60;
+		}
+		break;
+	case 'n':
+		name = EARGF(usage());
+		break;
+	case 's':
+		s = atoi(EARGF(usage()));
+		break;
+	}ARGEND
+
+	if(argc != 2)
+		usage();
+
+	if((cons = open(argv[0], OWRITE)) < 0)
+		sysfatal("open %s: %r", argv[0]);
+
+	if(chdir(argv[1]) < 0)
+		sysfatal("chdir %s: %r", argv[1]);
+
+	rfork(RFNOTEG);
+	switch(fork()){
+	case -1:
+		sysfatal("fork: %r");
+	case 0:
+		break;
+	default:
+		exits(0);
+	}
+
+	/*
+	 * pause at boot time to let clock stabilize.
+	 */
+	if(s)
+		sleep(s*1000);
+
+	for(;;){
+		if(access(snapnow(), AEXIST) < 0)
+			fprint(cons, "\nfsys %s snap -a\n", name);
+		t = time(0);
+		sleep((i - t%i)*1000+200);
+		if(!onlyarchive)
+			fprint(cons, "\nfsys %s snap\n", name);
+	}
+}