utils-std

time.c (4955B)

// utils-std: Collection of commonly available Unix tools
// SPDX-FileCopyrightText: 2017 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
// SPDX-License-Identifier: MPL-2.0
#define _POSIX_C_SOURCE 200809L
#include "../libutils/getopt_nolong.h"
#include <errno.h>
#include <signal.h>
#include <spawn.h>
#include <stdio.h>        // perror, fprintf
#include <stdlib.h>       // abort
#include <string.h>       // strerror
#include <sys/resource.h> // getrusage
#include <sys/times.h>
#include <sys/wait.h> // waitpid
#include <unistd.h>   // sysconf, getopt
extern char **environ;
const char *argv0 = "time";
static pid_t child = -1;
enum cmd_time_mode
{
	CMD_TIME_POSIX = 0,
	CMD_TIME_VERBOSE = 1,
};
/*
 * no-op signal handler so sigprocmask/sigwait works on BSDs where signals
 * that are ignored/discarded by default aren't blocked unless they
 * have a handler
 */
static void
sig_noop(int sig)
{
	return;
}
static void
usage(void)
{
	fprintf(stderr, "Usage: time [-p|-v] command [argument ...]\n");
}
int
main(int argc, char *argv[])
{
	struct tms tms;
	int ret = 0;
	enum cmd_time_mode mode = CMD_TIME_POSIX;
	if(argc <= 1)
	{
		usage();
		return 0;
	}
	for(int c = -1; (c = getopt_nolong(argc, argv, ":pv")) != -1;)
	{
		switch(c)
		{
		case 'p': // POSIX format (default)
			mode = CMD_TIME_POSIX;
			break;
		case 'v':
			mode = CMD_TIME_VERBOSE;
			break;
		case ':':
			fprintf(stderr, "time: error: Missing operand for option: '-%c'\n", optopt);
			usage();
			return 1;
		case '?':
			GETOPT_UNKNOWN_OPT
			usage();
			return 1;
		}
	}
	argc -= optind;
	argv += optind;
	(void)argc;
	long ticks = sysconf(_SC_CLK_TCK);
	if(ticks <= 0)
	{
		perror("time: error: sysconf(_SC_CLK_TCK)");
		return 1;
	}
	clock_t t0 = times(&tms);
	if(t0 == (clock_t)-1)
	{
		perror("time: error: times");
		return 1;
	}
	sigset_t sigset;
	if(sigfillset(&sigset) != 0) return 1;
	struct sigaction sa = {
		.sa_handler = &sig_noop,
		.sa_flags = 0,
	};
	if(sigaction(SIGCHLD, &sa, NULL) != 0)
	{
		fprintf(stderr, "time: error: Failed setting SIGCHLD handler: %s\n", strerror(errno));
		return 1;
	}
	if(sigprocmask(SIG_BLOCK, &sigset, NULL) != 0)
	{
		fprintf(stderr, "time: error: Failed setting process' signal mask: %s\n", strerror(errno));
		return 1;
	}
	if(posix_spawnp(&child, argv[0], NULL, NULL, argv, environ) != 0)
	{
		ret = 126 + (errno == ENOENT);
		fprintf(stderr, "time: error: Failed executing '%s': %s\n", argv[0], strerror(errno));
		return ret;
	}
	int status = 0;
	// Loop so signals are repeateadly propagated until child terminates
	while(true)
	{
		int sig = -1;
		if(sigwait(&sigset, &sig) != 0)
		{
			fprintf(stderr, "time: error: Failed waiting for signals: %s\n", strerror(errno));
			return 1;
		}
		int ret = waitpid(child, &status, WNOHANG);
		if(ret == child)
		{
			child = -1;
			break;
		}
		else if(ret == -1)
		{
			fprintf(stderr, "time: error: Failed waiting for child process: %s\n", strerror(errno));
			return 1;
		}
		if(kill(child, sig) != 0)
		{
			// candicate for sig2str
			fprintf(stderr,
			        "time: warning: Failed propagating signal number %d to child process (%d): %s\n",
			        sig,
			        child,
			        strerror(errno));
		}
	}
	clock_t t1 = times(&tms);
	if(t1 == -1)
	{
		perror("time: error: times");
		return 1;
	}
	if(WIFSIGNALED(status))
	{
		fprintf(stderr, "time: error: Command terminated by signal %d\n", WTERMSIG(status));
		ret = 128 + WTERMSIG(status);
	}
	struct rusage usage;
	if(getrusage(RUSAGE_CHILDREN, &usage) != 0)
	{
		fprintf(
		    stderr, "time: error: Failed getting resource usage of children: %s\n", strerror(errno));
		return 1;
	}
	double utime_s = usage.ru_utime.tv_sec + (usage.ru_utime.tv_usec * 0.000001);
	double stime_s = usage.ru_stime.tv_sec + (usage.ru_stime.tv_usec * 0.000001);
	switch(mode)
	{
	case CMD_TIME_POSIX:
		fprintf(stderr, "real %f\nuser %f\nsys %f\n", (t1 - t0) / (double)ticks, utime_s, stime_s);
		break;
	case CMD_TIME_VERBOSE:
		fprintf(stderr, "\tExecutable: %s\n", argv[0]);
		fprintf(stderr, "\tReal time  : %06f\n", (t1 - t0) / (double)ticks);
		fprintf(stderr, "\tUser time  : %06f\n", utime_s);
		fprintf(stderr, "\tSystem time: %06f\n", stime_s);
#ifdef __linux__
		fprintf(stderr, "\tMaximum resident set size (maxrss): %ld kB\n", usage.ru_maxrss);
		fprintf(stderr, "\tMinor (no I/O required) page faults (minflt): %ld\n", usage.ru_minflt);
		fprintf(stderr, "\tMajor (I/O required) page faults (majflt): %ld\n", usage.ru_majflt);
		fprintf(stderr, "\tMajor (I/O required) page faults (majflt): %ld\n", usage.ru_majflt);
		fprintf(stderr, "\tVoluntary context switch (nvcsw): %ld\n", usage.ru_nvcsw);
		fprintf(stderr, "\tInvoluntary context switch (nivcsw): %ld\n", usage.ru_nivcsw);
#endif
		if(WIFEXITED(status)) fprintf(stderr, "\tExit status: %d\n", WEXITSTATUS(status));
		break;
	default:
		abort();
	}
	if(WIFEXITED(status))
	{
		ret = WEXITSTATUS(status);
	}
	return ret;
}