add time. do not mark complete/POSIX compliant as exit status is wrong.

Makefile

@@ -137,6 +137,7 @@ BIN =\
 	tar\
 	tee\
 	test\
+	time\
 	touch\
 	tr\
 	true\

README

@@ -74,6 +74,7 @@ The following tools are implemented ('*' == finished, '#' == UTF-8 support,
 =* tar             non-posix                    none
 =* tee             yes                          none
 =* test            yes                          none
+=  time            no                           none (incorrect exit status)
 =* touch           yes                          none
 #* tr              yes                          none
 =* true            yes                          none

time.c

@@ -0,0 +1,63 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/times.h>
+#include <sys/wait.h>
+
+#include "util.h"
+
+void
+usage(void)
+{
+	eprintf("usage: %s [-p] utility [argument ...]\n", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	pid_t pid;
+	struct tms tms; /* hold user and sys times */
+	clock_t rbeg, rend; /* real time */
+	long ticks; /* per second */
+	int status;
+
+	ARGBEGIN {
+	case 'p':
+		/* used to specify POSIX output format, but that's the only format we
+		 * have for now */
+		break;
+	default:
+		usage();
+	} ARGEND;
+
+	if (!*argv)
+		usage();
+
+	if ((ticks = sysconf(_SC_CLK_TCK)) < 0)
+		eprintf("sysconf() failed to retrieve clock ticks per second:");
+
+	if ((rbeg = times(&tms)) < 0) /* POSIX doesn't say NULL is ok... */
+		eprintf("times() failed to retrieve start times:");
+
+	if (!(pid = fork())) { /* child */
+		execvp(*argv, argv);
+		/* FIXME: check errno for POSIX exit status
+		 * 126: found could not be invoked
+		 * 127: could not be found
+		 * problem is some like EACCESS can mean either...
+		 * worth doing manual path search for correct value? also gives more
+		 * accurate time as the patch search wouldn't be included in child's
+		 * user/sys times... */
+		enprintf(127, "failed to exec %s:", *argv);
+	}
+	waitpid(pid, &status, 0);
+
+	if ((rend = times(&tms)) < 0)
+		eprintf("times() failed to retrieve end times:");
+
+	fprintf(stderr, "real %f\nuser %f\nsys %f\n",
+	        (rend - rbeg)  / (double)ticks,
+	        tms.tms_cutime / (double)ticks,
+	        tms.tms_cstime / (double)ticks);
+
+	return WIFEXITED(status) ? WEXITSTATUS(status) : 0;
+}