/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1987, 1988, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1987, 1988, 1993\n\
	The Regents of the University of California.  All rights reserved.\n");
#endif /* not lint */

#ifndef lint
#if 0
__SCCSID("@(#)time.c	8.1 (Berkeley) 6/6/93");
#endif
__FBSDID("$FreeBSD$");
#endif /* not lint */

#include <sys/types.h>
#include <sys/resource.h>
#include <sys/signal.h>
#include <sys/sysctl.h>
#include <sys/time.h>
#include <sys/wait.h>

#include <err.h>
#include <errno.h>
#include <inttypes.h>
#include <libproc.h>
#include <locale.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

static int getstathz(void);
static void humantime(FILE *, long, long);
static void showtime(FILE *, struct timespec *, struct timespec *,
    struct rusage *);
static void siginfo(int);
static void usage(void);

static sig_atomic_t siginfo_recvd;
static char decimal_point;
static struct timespec before_ts;
static int hflag, pflag;
static volatile sig_atomic_t child_running = 1;
#ifdef __APPLE__
static pid_t pid = -1;
#endif

void
child_handler(int sig)
{
	child_running = 0;
}

#ifdef __APPLE__
static void
forward_signal_handler(int sig)
{

	/*
	 * If the process is still running, forward the signal which should have
	 * terminated us, which will then propagate back up via child wait
	 * status while still reporting.  If we can't kill(2) it, we'll just
	 * fall through to re-raising the signal and hoping for the best.
	 */
	if (pid != -1 && child_running && kill(pid, sig) == 0)
		return;

	signal(sig, SIG_DFL);
	raise(sig);
}
#endif	/* __APPLE__ */

int
main(int argc, char **argv)
{
	int aflag, ch, lflag, status, rusage_ret = -1;
	int exitonsig;
#ifndef __APPLE__
	pid_t pid;
#endif
	struct rlimit rl;
	struct rusage ru;
	struct rusage_info_v4 ruinfo;
	sigset_t sigmask, suspmask, origmask;
	struct timespec after;
	char *ofn = NULL;
	FILE *out = stderr;
#ifdef __APPLE__
	struct sigaction osa;
	bool sigint_ignored = false, sigquit_ignored = false;
#endif

	(void) setlocale(LC_NUMERIC, "");
	decimal_point = localeconv()->decimal_point[0];

	aflag = hflag = lflag = pflag = 0;
	while ((ch = getopt(argc, argv, "ahlo:p")) != -1)
		switch((char)ch) {
		case 'a':
			aflag = 1;
			break;
		case 'h':
			hflag = 1;
			break;
		case 'l':
			lflag = 1;
			break;
		case 'o':
			ofn = optarg;
			break;
		case 'p':
			pflag = 1;
			break;
		case '?':
		default:
			usage();
		}

	if (!(argc -= optind))
		exit(0);
	argv += optind;

	sigemptyset(&sigmask);
	/*
	 * Block SIGCHLD so that the check for `child_running` doesn't miss the
	 * handler before calling `sigsuspend` and blocking forever.
	 */
	sigaddset(&sigmask, SIGCHLD);
	sigprocmask(SIG_BLOCK, &sigmask, &origmask);

	/*
	 * Ensure child signals are handled by the parent prior to fork; otherwise,
	 * they could be missed between the child forking and calling `sigsuspend`.
	 */
	(void)signal(SIGCHLD, child_handler);

	sigemptyset(&suspmask);

	if (ofn) {
	        if ((out = fopen(ofn, aflag ? "ae" : "we")) == NULL)
		        err(1, "%s", ofn);
		setvbuf(out, (char *)NULL, _IONBF, (size_t)0);
	}

#ifdef __APPLE__
	/*
	 * Checked in advance to avoid disturbing our measurements with extra
	 * syscall trips.
	 */
	if (sigaction(SIGINT, NULL, &osa) == 0)
		sigint_ignored = osa.sa_handler == SIG_IGN;
	if (sigaction(SIGQUIT, NULL, &osa) == 0)
		sigquit_ignored = osa.sa_handler == SIG_IGN;
#endif

	if (clock_gettime(CLOCK_MONOTONIC, &before_ts))
		err(1, "clock_gettime");
	/*
	 * NB: Don't add anything between these two lines -- measurement is
	 * happening now.
	 */
	switch(pid = fork()) {
	case -1:			/* error */
		err(1, "time");
		/* NOTREACHED */
	case 0:				/* child */
		/*
		 * Allow the child to respond to signals by resetting to the original
		 * signal handling behavior.
		 */
		(void)sigprocmask(SIG_SETMASK, &origmask, NULL);
		execvp(*argv, argv);
		err(errno == ENOENT ? 127 : 126, "%s", *argv);
		/* NOTREACHED */
	default:			/* parent */
		break;
	}

	/*
	 * Let the child handle signals that normally exit, unless they were
	 * inherited as ignored.
	 */
#ifdef __APPLE__
	if (!sigint_ignored)
		signal(SIGINT, forward_signal_handler);
	if (!sigquit_ignored)
		signal(SIGQUIT, forward_signal_handler);
#else
	(void)signal(SIGINT, SIG_IGN);
	(void)signal(SIGQUIT, SIG_IGN);
#endif
	siginfo_recvd = 0;
	(void)signal(SIGINFO, siginfo);
	(void)siginterrupt(SIGINFO, 1);
	while (child_running) {
		if (siginfo_recvd) {
			siginfo_recvd = 0;
			if (clock_gettime(CLOCK_MONOTONIC, &after))
				err(1, "clock_gettime");
			getrusage(RUSAGE_CHILDREN, &ru);
			showtime(stdout, &before_ts, &after, &ru);
		}
		/*
		 * This would be racy, but SIGCHLD is blocked above (as part of
		 * `sigmask`).
		 */
		sigsuspend(&suspmask);
	}
	/*
	 * minimize what's added between these statements to preserve the
	 * accuracy of the time measurement.
	 */
	if (clock_gettime(CLOCK_MONOTONIC, &after))
		err(1, "clock_gettime");
	if (lflag) {
		rusage_ret = proc_pid_rusage(pid, RUSAGE_INFO_V4, (void **)&ruinfo);
	}
	while (wait4(pid, &status, 0, &ru) != pid) {
	}
	if ( ! WIFEXITED(status))
		warnx("command terminated abnormally");
	exitonsig = WIFSIGNALED(status) ? WTERMSIG(status) : 0;
	showtime(out, &before_ts, &after, &ru);
	if (lflag) {
		int hz = getstathz();
		u_long ticks;

		ticks = hz * (ru.ru_utime.tv_sec + ru.ru_stime.tv_sec) +
		     hz * (ru.ru_utime.tv_usec + ru.ru_stime.tv_usec) / 1000000;

		/*
		 * If our round-off on the tick calculation still puts us at 0,
		 * then always assume at least one tick.
		 */
		if (ticks == 0)
			ticks = 1;

		fprintf(out, "%20ld  %s\n",
			ru.ru_maxrss, "maximum resident set size");
		fprintf(out, "%20ld  %s\n",
			ru.ru_ixrss / ticks, "average shared memory size");
		fprintf(out, "%20ld  %s\n",
			ru.ru_idrss / ticks, "average unshared data size");
		fprintf(out, "%20ld  %s\n",
			ru.ru_isrss / ticks, "average unshared stack size");
		fprintf(out, "%20ld  %s\n",
			ru.ru_minflt, "page reclaims");
		fprintf(out, "%20ld  %s\n",
			ru.ru_majflt, "page faults");
		fprintf(out, "%20ld  %s\n",
			ru.ru_nswap, "swaps");
		fprintf(out, "%20ld  %s\n",
			ru.ru_inblock, "block input operations");
		fprintf(out, "%20ld  %s\n",
			ru.ru_oublock, "block output operations");
		fprintf(out, "%20ld  %s\n",
			ru.ru_msgsnd, "messages sent");
		fprintf(out, "%20ld  %s\n",
			ru.ru_msgrcv, "messages received");
		fprintf(out, "%20ld  %s\n",
			ru.ru_nsignals, "signals received");
		fprintf(out, "%20ld  %s\n",
			ru.ru_nvcsw, "voluntary context switches");
		fprintf(out, "%20ld  %s\n",
			ru.ru_nivcsw, "involuntary context switches");

		if (rusage_ret >= 0) {
			if (ruinfo.ri_instructions > 0) {
				fprintf(out, "%20" PRIu64 "  %s\n", ruinfo.ri_instructions,
					"instructions retired");
			}
			if (ruinfo.ri_cycles > 0) {
				fprintf(out, "%20" PRIu64 "  %s\n", ruinfo.ri_cycles,
					"cycles elapsed");
			}
			if (ruinfo.ri_lifetime_max_phys_footprint > 0) {
				fprintf(out, "%20" PRIu64 "  %s\n",
					ruinfo.ri_lifetime_max_phys_footprint,
					"peak memory footprint");
			}
		}
	}
	/*
	 * If the child has exited on a signal, exit on the same
	 * signal, too, in order to reproduce the child's exit status.
	 * However, avoid actually dumping core from the current process.
	 */
	if (exitonsig) {
		if (signal(exitonsig, SIG_DFL) == SIG_ERR)
			warn("signal");
		else {
			rl.rlim_max = rl.rlim_cur = 0;
			if (setrlimit(RLIMIT_CORE, &rl) == -1)
				warn("setrlimit");
			kill(getpid(), exitonsig);
		}
	}
	exit (WIFEXITED(status) ? WEXITSTATUS(status) : EXIT_FAILURE);
}

static void
usage(void)
{
	fprintf(stderr,
	    "usage: time [-al] [-h | -p] [-o file] utility [argument ...]\n");
	exit(1);
}

/*
 * Return the frequency of the kernel's statistics clock.
 */
static int
getstathz(void)
{
	int mib[2];
	size_t size;
	struct clockinfo clockrate;

	mib[0] = CTL_KERN;
	mib[1] = KERN_CLOCKRATE;
	size = sizeof clockrate;
	if (sysctl(mib, 2, &clockrate, &size, NULL, 0) == -1)
		err(1, "sysctl kern.clockrate");
	return clockrate.stathz;
}

static void
humantime(FILE *out, long sec, long centisec)
{
	long days, hrs, mins;

	days = sec / (60L * 60 * 24);
	sec %= (60L * 60 * 24);
	hrs = sec / (60L * 60);
	sec %= (60L * 60);
	mins = sec / 60;
	sec %= 60;

	fprintf(out, "\t");
	if (days)
		fprintf(out, "%ldd", days);
	if (hrs)
		fprintf(out, "%ldh", hrs);
	if (mins)
		fprintf(out, "%ldm", mins);
	fprintf(out, "%ld%c%02lds", sec, decimal_point, centisec);
}

static void
showtime(FILE *out, struct timespec *before, struct timespec *after,
    struct rusage *ru)
{

	after->tv_sec -= before->tv_sec;
	after->tv_nsec -= before->tv_nsec;
	if (after->tv_nsec < 0)
		(void)after->tv_sec--, after->tv_nsec += 1000000000;

	if (pflag) {
		/* POSIX wants output that must look like
		"real %f\nuser %f\nsys %f\n" and requires
		at least two digits after the radix. */
		fprintf(out, "real %jd%c%02ld\n",
			(intmax_t)after->tv_sec, decimal_point,
			after->tv_nsec/10000000);
		fprintf(out, "user %jd%c%02ld\n",
			(intmax_t)ru->ru_utime.tv_sec, decimal_point,
			(long)ru->ru_utime.tv_usec/10000);
		fprintf(out, "sys %jd%c%02ld\n",
			(intmax_t)ru->ru_stime.tv_sec, decimal_point,
			(long)ru->ru_stime.tv_usec/10000);
	} else if (hflag) {
		humantime(out, after->tv_sec, after->tv_nsec/10000000);
		fprintf(out, " real\t");
		humantime(out, ru->ru_utime.tv_sec, ru->ru_utime.tv_usec/10000);
		fprintf(out, " user\t");
		humantime(out, ru->ru_stime.tv_sec, ru->ru_stime.tv_usec/10000);
		fprintf(out, " sys\n");
	} else {
		fprintf(out, "%9jd%c%02ld real ",
			(intmax_t)after->tv_sec, decimal_point,
			after->tv_nsec/10000000);
		fprintf(out, "%9jd%c%02ld user ",
			(intmax_t)ru->ru_utime.tv_sec, decimal_point,
			(long)ru->ru_utime.tv_usec/10000);
		fprintf(out, "%9jd%c%02ld sys\n",
			(intmax_t)ru->ru_stime.tv_sec, decimal_point,
			(long)ru->ru_stime.tv_usec/10000);
	}
}

static void
siginfo(int sig __unused)
{

	siginfo_recvd = 1;
}