time

[Kurt H Maier <khm@sciops.net>]

Attached is a patch from BurnZeZ that modifies the precision of time(1).
Any objections?  I'd like the functionality but I don't want to commit
it without input.

khm

diff -r 5c5acc9ab7a5 sys/src/cmd/time.c
--- a/sys/src/cmd/time.c	Sat Aug 11 16:19:32 2018 +0200
+++ b/sys/src/cmd/time.c	Sat Aug 11 20:40:06 2018 +0000
@@ -14,16 +14,22 @@
 	long l;
 	char *p;
 	char err[ERRMAX];
+	vlong *t0, t1;
+	enum { SEC = 1000000000ULL };
 
 	if(argc <= 1){
 		fprint(2, "usage: time command\n");
 		exits("usage");
 	}
 
+	if((t0 = segattach(SG_CEXEC, "shared", nil, sizeof(*t0))) == nil)
+		sysfatal("segattach: %r");
+	*t0 = 0;
 	switch(fork()){
 	case -1:
 		error("fork");
 	case 0:
+		*t0 = nsec();
 		exec(argv[1], &argv[1]);
 		if(argv[1][0] != '/' && strncmp(argv[1], "./", 2) &&
 		   strncmp(argv[1], "../", 3)){
@@ -43,12 +49,14 @@
 			goto loop;
 		error("wait");
 	}
+	t1 = nsec();
 	l = w->time[0];
 	add("%ld.%.2ldu", l/1000, (l%1000)/10);
 	l = w->time[1];
 	add("%ld.%.2lds", l/1000, (l%1000)/10);
 	l = w->time[2];
 	add("%ld.%.2ldr", l/1000, (l%1000)/10);
+	add("%lld.%.9lldt", (t1-*t0)/SEC, (t1-*t0)%SEC);
 	add("\t");
 	for(i=1; i<argc; i++){
 		add("%s", argv[i], 0);