utils

sleep.c (2594B)

// Collection of Unix tools, comparable to coreutils
// SPDX-FileCopyrightText: 2017-2023 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
// SPDX-License-Identifier: MPL-2.0
#define _POSIX_C_SOURCE 200809L
#include <errno.h>  // errno
#include <stdio.h>  // fprintf, perror, sscanf
#include <stdlib.h> // exit
#include <time.h>   // nanosleep, timespec
// Maybe should be moved in ./lib with iso_parse
static struct timespec
strtodur(char *s)
{
	struct timespec dur = {.tv_sec = 0, .tv_nsec = 0};
	if(s[0] == 0)
	{
		fprintf(stderr, "sleep: Got an empty string as duration\n");
		return dur;
	}
	int parsed = 0;
	if(s[0] != '.' && s[0] != ',')
	{
		errno   = 0;
		int ret = sscanf(s, "%10ld%n", &dur.tv_sec, &parsed);
		if(ret < 1)
		{
			if(errno == 0)
			{
				fprintf(stderr, "sleep: Not a number: %s\n", s);
			}
			else
			{
				perror("sleep: sscanf");
			}
			exit(EXIT_FAILURE);
		}
		s += parsed;
		if(s[0] == 0) return dur;
	}
	if(s[0] == '.' || s[0] == ',')
	{
		float fraction = 0.0;
		if(s[1] == 0) return dur;
		if(s[0] == ',') s[0] = '.';
		parsed = 0;
		errno  = 0;
		if(sscanf(s, "%10f%n", &fraction, &parsed) < 1)
		{
			if(errno == 0)
			{
				fprintf(stderr, "sleep: Decimal part is not a number: %s\n", s);
			}
			else
			{
				perror("sleep: sscanf");
			}
			exit(EXIT_FAILURE);
		}
		dur.tv_nsec = fraction * 1000000000;
		s += parsed;
	}
	if(s[0] == 0) return dur;
	if(s[1] != 0)
	{
		fprintf(stderr, "sleep: suffix '%s' is too long, should be only one character\n", s);
		exit(1);
	}
	switch(s[0])
	{
	case 's': // seconds
		break;
	case 'm': // minutes
		dur.tv_sec *= 60;
		break;
	case 'h': // hours
		dur.tv_sec *= 60 * 60;
		break;
	default:
		fprintf(stderr, "sleep: Unknown suffix %c\n", s[0]);
		exit(1);
	}
	return dur;
}
int
main(int argc, char *argv[])
{
	struct timespec dur = {.tv_sec = 0, .tv_nsec = 0};
	for(int i = 1; i < argc; i++)
	{
		struct timespec arg_dur = strtodur(argv[i]);
		dur.tv_sec += arg_dur.tv_sec;
		dur.tv_nsec += arg_dur.tv_nsec;
		if(dur.tv_nsec > 999999999)
		{
			dur.tv_nsec = 0;
			dur.tv_sec += 1;
		}
	}
	if(dur.tv_sec == 0 && dur.tv_nsec == 0)
	{
		fprintf(stderr, "sleep: Got a duration of 0\n");
		return 1;
	}
	//fprintf(stderr, "sleep: going to sleep for %ld.%09ld seconds\n", dur.tv_sec, dur.tv_nsec);
	errno = 0;
	if(nanosleep(&dur, &dur) < 0)
	{
		if(errno == EINTR)
		{
			fprintf(stderr,
			        "sleep: Interrupted during sleep, still had %ld.%09ld seconds remaining\n",
			        dur.tv_sec,
			        dur.tv_nsec);
		}
		else
		{
			perror("sleep: nanosleep");
		}
	}
	return 0;
}