109 lines
1.9 KiB
C
109 lines
1.9 KiB
C
#define _XOPEN_SOURCE
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <time.h>
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const char *fmts[] = {
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"%R",
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"%T",
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"%d-%m",
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"%d-%m %H",
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"%d-%m %R",
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"%d-%m %T",
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"%d-%m-%Y",
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"%d-%m-%Y %H",
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"%d-%m-%Y %R",
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"%d-%m-%Y %T"
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};
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time_t parse_date(char *str) {
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time_t local = time(NULL);
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struct tm *tm = localtime(&local);
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char flag = 0;
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for (size_t i = 0; i < sizeof(fmts) / sizeof(char *); i++) {
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char *res = strptime(str, fmts[i], tm);
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if (res && *res == '\0') {
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flag = 1;
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break;
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}
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}
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if (flag == 0) {
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fprintf(stderr, "date: parsing: invalid format\n");
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exit(1);
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}
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time_t rt = mktime(tm);
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if (rt < 0) {
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if (rt == -1)
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fprintf(stderr, "date: parsing: %s\n", strerror(errno));
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else
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fprintf(stderr, "date: parsing: invalid date\n");
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exit(1);
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}
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return rt;
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}
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int main(int argc, char **argv) {
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time_t t = time(NULL);
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char *fmt = "%a %b %e %H:%M:%S %Z %Y";
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/* For -s flag */
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struct timespec ts;
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int opt;
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while ((opt = getopt(argc, argv, "s:d:u")) != -1) {
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switch (opt) {
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case 's':
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ts.tv_sec = parse_date(optarg);
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if (clock_settime(CLOCK_REALTIME, &ts) < 0) {
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fprintf(stderr, "date: settime: %s\n", strerror(errno));
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return 1;
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}
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return 0;
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case 'd':
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t = parse_date(optarg);
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break;
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case 'u':
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if (setenv("TZ", "UTC0", 1) < 0) {
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fprintf(stderr, "date: %s\n", strerror(errno));
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return 1;
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}
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break;
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default:
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puts("date [rsdu] [+\"fmt\"]\n\t-s TIME Set new date\n\t-d TIME Print new date\n\t-u Work in UTC\n\nRecognized TIME formats:");
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for (size_t i = 0; i < sizeof(fmts) / sizeof(char *); i++)
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puts(fmts[i]);
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return 0;
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}
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}
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argv += optind;
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argc -= optind;
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if (argc != 0)
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if (argv[0][0] == '+')
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fmt = argv[0] + 1;
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struct tm *tm = localtime(&t);
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char buf[256];
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strftime(buf, sizeof(buf), fmt, tm);
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puts(buf);
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return 0;
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}
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