toaruos/apps/date.c

136 lines
3.7 KiB
C

/**
* date - Print the current date and time.
*
* TODO: The traditional POSIX version of this tool is supposed
* to accept a format *and* allow you to set the time.
* We currently lack system calls for setting the time,
* but when we add those this should probably be updated.
*
* At the very least, improving this to print the "correct"
* default format would be good.
*
* @copyright
* This file is part of ToaruOS and is released under the terms
* of the NCSA / University of Illinois License - see LICENSE.md
* Copyright (C) 2018 K. Lange
*/
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <sys/time.h>
static void show_usage(int argc, char * argv[]) {
printf(
"%s - print the time and day\n"
"\n"
"usage: %s [-?] +FORMAT\n"
"\n"
" Note: This implementation is not currently capable of\n"
" setting the system time.\n"
"\n"
" -? \033[3mshow this help text\033[0m\n"
"\n", argv[0], argv[0]);
}
int digits(const char * s, int len) {
for (int i = 0; i < len; ++i) {
if (s[i] < '0' || s[i] > '9') return 0;
}
return 1;
}
int mmddhhmm(struct tm * tm, const char * str) {
int month = (str[0]-'0') * 10 + (str[1]-'0');
int day = (str[2]-'0') * 10 + (str[3]-'0');
int hour = (str[4]-'0') * 10 + (str[5]-'0');
int min = (str[6]-'0') * 10 + (str[7]-'0');
if (month < 1 || month > 12) return 0;
if (day < 1 || day > 31) return 0;
if (hour < 0 || hour > 23) return 0;
if (min < 0 || min > 59) return 0;
tm->tm_mon = month - 1;
tm->tm_mday = day;
tm->tm_hour = hour;
tm->tm_min = min;
return 1;
}
int ddyy(struct tm * tm, const char * str) {
int year = (str[0]-'0') * 1000 + (str[1]-'0') * 100 + (str[2]-'0') * 10 + (str[3]-'0');
tm->tm_year = year - 1900;
return 1;
}
int secs(struct tm * tm, const char * str) {
int sec = (str[0]-'0') * 10 + (str[1]-'0');
if (sec < 0 || sec > 59) return 0;
tm->tm_sec = sec;
return 1;
}
int main(int argc, char * argv[]) {
char * format = "%a %d %b %Y %T %Z";
struct tm * timeinfo;
struct timeval now;
char buf[BUFSIZ] = {0};
int opt;
while ((opt = getopt(argc,argv,"?")) != -1) {
switch (opt) {
case '?':
show_usage(argc,argv);
return 1;
}
}
gettimeofday(&now, NULL);
timeinfo = localtime((time_t *)&now.tv_sec);
if (optind < argc && *argv[optind] == '+') {
format = &argv[optind][1];
} else if (optind < argc) {
int len =strlen(argv[optind]);
if (len == 8) {
if (!digits(argv[optind], 8)) goto _invalid;
if (!mmddhhmm(timeinfo, argv[optind])) goto _invalid;
goto set_time;
} else if (len == 11) {
if (argv[optind][8] != '.') goto _invalid;
if (!digits(argv[optind], 8) || !digits(argv[optind]+9,2)) goto _invalid;
if (!mmddhhmm(timeinfo, argv[optind])) goto _invalid;
if (!secs(timeinfo, argv[optind]+9)) goto _invalid;
goto set_time;
} else if (len == 12) {
if (!digits(argv[optind], 12)) goto _invalid;
if (!mmddhhmm(timeinfo, argv[optind])) goto _invalid;
if (!ddyy(timeinfo, argv[optind]+8)) goto _invalid;
goto set_time;
} else if (len == 15) {
if (argv[optind][12] != '.') goto _invalid;
if (!digits(argv[optind], 12) || !digits(argv[optind]+13,2)) goto _invalid;
if (!mmddhhmm(timeinfo, argv[optind])) goto _invalid;
if (!ddyy(timeinfo, argv[optind]+8)) goto _invalid;
if (!secs(timeinfo, argv[optind]+13)) goto _invalid;
goto set_time;
}
_invalid:
fprintf(stderr, "date: only 'MMDDhhmm', 'MMDDhhmm.ss', 'MMDDhhmmCCYY' and 'MMDDhhmmCCYY.ss' are supported for setting time.\n");
return 1;
set_time:
now.tv_usec = 0;
now.tv_sec = mktime(timeinfo);
return settimeofday(&now, NULL);
}
strftime(buf,BUFSIZ,format,timeinfo);
puts(buf);
return 0;
}