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utils-std

Collection of commonly available Unix tools git clone https://anongit.hacktivis.me/git/utils-std.git/

date.c (8636B)

    

  1. // utils-std: Collection of commonly available Unix tools
  2. // SPDX-FileCopyrightText: 2017 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
  3. // SPDX-License-Identifier: MPL-2.0
  5. #define _DEFAULT_SOURCE // tm_gmtoff/tm_zone
  6. #define _POSIX_C_SOURCE 200809L
  7. #define _XOPEN_SOURCE 700 // strptime is in XSI
  9. #include "../lib/getopt_nolong.h"
  10. #include "../lib/iso_parse.h" /* iso_parse */
  12. #include <assert.h>
  13. #include <errno.h>
  14. #include <locale.h> /* setlocale() */
  15. #include <stdbool.h>
  16. #include <stdio.h>  /* BUFSIZ, fprintf(), puts() */
  17. #include <stdlib.h> /* strtol() */
  18. #include <string.h> /* strerror */
  19. #include <time.h>   /* time, localtime, tm, strftime, strptime, clock_settime */
  20. #include <unistd.h> /* getopt(), opt… */
  22. const char *argv0 = "date";
  24. static size_t
  25. date_strftime(char *restrict buf,
  26.               size_t buflen,
  27.               const char *restrict fmt,
  28.               const struct tm *restrict tm,
  29.               long nsec)
  30. {
  31. 	size_t fmtlen = strlen(fmt);
  32. 	size_t printed = 0;
  34. 	if(fmtlen == 0)
  35. 	{
  36. 		buf[0] = '\0';
  37. 		return 0;
  38. 	}
  40. 	for(size_t i = 0; i < fmtlen;)
  41. 	{
  42. 		// size taken from musl strftime
  43. 		static char fmt_buf[100] = "";
  44. 		size_t fmt_bufi = 0;
  46. 		if(fmt[i] == '%')
  47. 		{
  48. 			fmt_buf[fmt_bufi++] = fmt[i++];
  50. 			if(fmt[i] == '%') // handle '%%'
  51. 			{
  52. 				*buf = '%';
  53. 				buf++;
  54. 				buflen--;
  55. 				printed++;
  56. 				i++;
  57. 				continue;
  58. 			}
  59. 		}
  61. 		for(; fmt[i] != '%' && i < fmtlen;)
  62. 		{
  63. 			fmt_buf[fmt_bufi++] = fmt[i++];
  64. 			assert(fmt_bufi < 100);
  65. 		}
  67. 		fmt_buf[fmt_bufi] = '\0';
  69. 		if(fmt_buf[0] == '%' && fmt_buf[1] == ':' && fmt_buf[2] == 'z')
  70. 		{
  71. 			size_t got =
  72. 			    snprintf(buf, buflen, "%+.2ld:%.2ld", tm->tm_gmtoff / 3600, tm->tm_gmtoff % 3600 / 60);
  73. 			if(got == 0) return got;
  75. 			buf += got;
  76. 			buflen -= got;
  77. 			printed += got;
  78. 		}
  79. 		else if(fmt_buf[0] == '%' && fmt_buf[1] == 'N')
  80. 		{
  81. 			size_t got = snprintf(buf, buflen, "%09ld", nsec);
  82. 			if(got == 0) return got;
  84. 			buf += got;
  85. 			buflen -= got;
  86. 			printed += got;
  87. 		}
  88. 		else
  89. 		{
  90. 			size_t got = strftime(buf, buflen, fmt_buf, tm);
  91. 			if(got == 0) return got;
  93. 			buf += got;
  94. 			buflen -= got;
  95. 			printed += got;
  96. 		}
  97. 	}
  99. 	return printed;
  100. }
  102. static void
  103. usage(void)
  104. {
  105. 	fprintf(stderr, "\
  106. Usage:\n\
  107. 	date [-jRu] [-I iso_fmt] [-d datetime | -r epoch] [+format]\n\
  108. 	date [-jRu] [-I iso_fmt] mmddHHMM[[CC]yy] [+format]\n\
  109. 	date [-jRu] [-I iso_fmt] -f now_format now [+format]\n\
  110. ");
  111. }
  113. int
  114. main(int argc, char *argv[])
  115. {
  116. 	char outstr[BUFSIZ] = "";
  117. 	struct tm tm = {
  118. 	    .tm_year = 0,
  119. 	    .tm_mon = 0,
  120. 	    .tm_mday = 0,
  121. 	    .tm_hour = 0,
  122. 	    .tm_min = 0,
  123. 	    .tm_sec = 0,
  124. 	    .tm_isdst = -1, // unknown if DST is in effect
  125. 	    .tm_gmtoff = 0,
  126. 	    .tm_zone = NULL,
  127. 	};
  128. 	struct timespec tp = {
  129. 	    .tv_sec = 0,
  130. 	    .tv_nsec = 0,
  131. 	};
  132. 	const char *format = "%c";
  133. 	const char *input_format = NULL;
  134. 	int uflag = 0;
  135. 	int dflag = 0, rflag = 0;
  136. 	bool jflag = false;
  137. 	bool settime = false;
  139. 	char *lc_all = setlocale(LC_ALL, "");
  140. 	if(lc_all == NULL)
  141. 	{
  142. 		fprintf(stderr,
  143. 		        "%s: warning: Failed loading locales. setlocale(LC_ALL, \"\"): %s\n",
  144. 		        argv0,
  145. 		        strerror(errno));
  146. 	}
  147. 	errno = 0;
  149. 	if(clock_gettime(CLOCK_REALTIME, &tp) != 0)
  150. 	{
  151. 		fprintf(stderr, "%s: error: Failed getting current time: %s\n", argv0, strerror(errno));
  152. 		return 1;
  153. 	}
  155. 	for(int c = -1; (c = getopt_nolong(argc, argv, ":d:f:I:jr:Ru")) != -1;)
  156. 	{
  157. 		const char *errstr = NULL;
  158. 		switch(c)
  159. 		{
  160. 		case 'd': /* Custom datetime */
  161. 			if(input_format != NULL)
  162. 			{
  163. 				fprintf(stderr, "%s: error: Cannot both use '-d' and '-f'\n", argv0);
  164. 				return 1;
  165. 			}
  166. 			if(rflag == 1)
  167. 			{
  168. 				fprintf(stderr, "%s: error: Cannot both use '-d' and '-r'\n", argv0);
  169. 				return 1;
  170. 			}
  172. 			iso_parse(optarg, &tm, &tp.tv_nsec, &errstr);
  173. 			dflag = 1;
  174. 			if(errstr != NULL)
  175. 			{
  176. 				fprintf(stderr, "%s: error: iso_parse(\"%s\", …): %s\n", argv0, optarg, errstr);
  177. 				return 1;
  178. 			}
  180. 			tp.tv_sec = mktime_tz(&tm);
  181. 			if(tp.tv_sec == (time_t)-1)
  182. 			{
  183. 				fprintf(stderr, "%s: error: mktime: %s\n", argv0, strerror(errno));
  184. 				return 1;
  185. 			}
  186. 			errno = 0;
  188. 			break;
  189. 		case 'f': /* input datetime format */
  190. 			if(dflag == 1)
  191. 			{
  192. 				fprintf(stderr, "%s: error: Cannot both use '-d' and '-f'\n", argv0);
  193. 				return 1;
  194. 			}
  195. 			if(rflag == 1)
  196. 			{
  197. 				fprintf(stderr, "%s: error: Cannot both use '-f' and '-r'\n", argv0);
  198. 				return 1;
  199. 			}
  201. 			input_format = optarg;
  202. 			settime = true;
  203. 			break;
  204. 		case 'r': /* seconds relative to epoch */
  205. 		{
  206. 			if(input_format != NULL)
  207. 			{
  208. 				fprintf(stderr, "%s: error: Cannot both use '-f' and '-r'\n", argv0);
  209. 				return 1;
  210. 			}
  211. 			if(dflag == 1)
  212. 			{
  213. 				fprintf(stderr, "%s: error: Cannot both use '-d' and '-r'\n", argv0);
  214. 				return 1;
  215. 			}
  217. 			char *endptr = NULL;
  218. 			errno = 0;
  219. 			tp.tv_sec = strtol(optarg, &endptr, 10);
  220. 			if(errno != 0)
  221. 			{
  222. 				fprintf(stderr, "%s: error: Failed parsing '-r %s'\n", argv0, optarg);
  223. 				return 1;
  224. 			}
  225. 			if(!(endptr == NULL || *endptr == '\0'))
  226. 			{
  227. 				fprintf(stderr, "%s: error: Invalid characters in '-r %s': %s\n", argv0, optarg, endptr);
  228. 				return 1;
  229. 			}
  230. 			break;
  231. 		}
  232. 		case 'R': /* Email (RFC 5322) format */
  233. 			format = "%a, %d %b %Y %H:%M:%S %z";
  234. 			break;
  235. 		case 'u': /* UTC timezone */
  236. 			uflag++;
  237. 			setenv("TZ", "UTC", 1);
  238. 			tzset();
  239. 			break;
  240. 		case 'I': /* ISO 8601 */
  241. 			/* note: %:z (±ZZ:ZZ) and %N (nanoseconds) are date(1) GNU-isms absent from C libraries including glibc */
  242. 			switch(optarg[0])
  243. 			{
  244. 			case 'h': // hours
  245. 				format = "%Y-%m-%dT%H%:z";
  246. 				break;
  247. 			case 'm': // minutes
  248. 				format = "%Y-%m-%dT%H:%M%:z";
  249. 				break;
  250. 			case 's': // seconds
  251. 				format = "%Y-%m-%dT%H:%M:%S%:z";
  252. 				break;
  253. 			case 'n': // ns, nanoseconds
  254. 				format = "%Y-%m-%dT%H:%M:%S,%N%:z";
  255. 				break;
  256. 			case 'd': // date
  257. 			default:
  258. 				format = "%Y-%m-%d";
  259. 				break;
  260. 			}
  261. 			break;
  262. 		case 'j':
  263. 			jflag = true;
  264. 			break;
  265. 		case ':':
  266. 			fprintf(stderr, "%s: error: Missing operand for option: '-%c'\n", argv0, optopt);
  267. 			usage();
  268. 			return 1;
  269. 		case '?':
  270. 			if(!got_long_opt) fprintf(stderr, "%s: error: Unrecognised option: '-%c'\n", argv0, optopt);
  271. 			usage();
  272. 			return 1;
  273. 		}
  274. 	}
  276. 	argc -= optind;
  277. 	argv += optind;
  279. 	if(uflag)
  280. 	{
  281. 		if(gmtime_r(&tp.tv_sec, &tm) == NULL)
  282. 		{
  283. 			fprintf(stderr, "%s: error: gmtime_r: %s\n", argv0, strerror(errno));
  284. 			return 1;
  285. 		}
  286. 	}
  287. 	else
  288. 	{
  289. 		if(localtime_r(&tp.tv_sec, &tm) == NULL)
  290. 		{
  291. 			fprintf(stderr, "%s: error: localtime_r: %s\n", argv0, strerror(errno));
  292. 			return 1;
  293. 		}
  294. 	}
  296. 	if(argc > 0 && input_format != NULL)
  297. 	{
  298. 		char *res = strptime(argv[0], input_format, &tm);
  300. 		if(res == NULL)
  301. 		{
  302. 			fprintf(stderr,
  303. 			        "%s: error: strptime(\"%s\", \"%s\", …) as passed by '-f' option failed\n",
  304. 			        argv0,
  305. 			        argv[0],
  306. 			        input_format);
  307. 			return 1;
  308. 		}
  310. 		tp.tv_sec = mktime_tz(&tm);
  311. 		tp.tv_nsec = 0;
  312. 		if(tp.tv_sec == (time_t)-1)
  313. 		{
  314. 			fprintf(stderr, "%s: error: mktime: %s\n", argv0, strerror(errno));
  315. 			return 1;
  316. 		}
  317. 		errno = 0;
  319. 		argv++;
  320. 		argc--;
  321. 	}
  323. 	if(input_format == NULL && argc > 0 && *argv && **argv != '+')
  324. 	{
  325. 		const char *fmt = "%m%d%H%M";
  326. 		char *s = strptime(argv[0], fmt, &tm);
  327. 		if(s == NULL)
  328. 		{
  329. 			fprintf(stderr, "%s: error: strptime(\"%s\", \"%s\", …) returned NULL\n", argv0, *argv, fmt);
  330. 			return 1;
  331. 		}
  333. 		size_t rem = strlen(s);
  334. 		if(rem > 0)
  335. 		{
  336. 			switch(rem)
  337. 			{
  338. 			case 2:
  339. 				fmt = "%y";
  340. 				break;
  341. 			case 4:
  342. 				fmt = "%Y";
  343. 				break;
  344. 			default:
  345. 				fprintf(stderr,
  346. 				        "%s: error: Got %zu trailing characters after \"%s\" for mmddHHMM\n",
  347. 				        argv0,
  348. 				        rem,
  349. 				        fmt);
  350. 				return 1;
  351. 			}
  353. 			s = strptime(s, fmt, &tm);
  354. 			if(s == NULL)
  355. 			{
  356. 				fprintf(
  357. 				    stderr, "%s: error: strptime(\"%s\", \"%s\", …) returned NULL\n", argv0, *argv, fmt);
  358. 				return 1;
  359. 			}
  360. 		}
  362. 		tp.tv_sec = mktime(&tm);
  363. 		tp.tv_nsec = 0;
  364. 		if(tp.tv_sec == (time_t)-1)
  365. 		{
  366. 			fprintf(stderr, "%s: error: mktime: %s\n", argv0, strerror(errno));
  367. 			return 1;
  368. 		}
  369. 		errno = 0;
  371. 		argv++;
  372. 		argc--;
  373. 		settime = true;
  374. 	}
  376. 	if(settime && !jflag)
  377. 	{
  378. 		if(clock_settime(CLOCK_REALTIME, &tp) != 0)
  379. 		{
  380. 			fprintf(stderr,
  381. 			        "%s: error: clock_settime(CLOCK_REALTIME, {%ld, %ld}): %s\n",
  382. 			        argv0,
  383. 			        tp.tv_sec,
  384. 			        tp.tv_nsec,
  385. 			        strerror(errno));
  386. 			return 1;
  387. 		}
  388. 	}
  390. 	if(argc > 0 && *argv && **argv == '+')
  391. 	{
  392. 		format = *argv + 1;
  394. 		argv++;
  395. 		argc--;
  396. 	}
  398. 	errno = 0;
  399. 	if(date_strftime(outstr, sizeof(outstr), format, &tm, tp.tv_nsec) == 0 && errno != 0)
  400. 	{
  401. 		fprintf(stderr, "%s: error: Failed formatting time: %s\n", argv0, strerror(errno));
  402. 		return 1;
  403. 	}
  405. 	if(puts(outstr) < 0)
  406. 	{
  407. 		fprintf(stderr, "%s: error: Failed writing time: %s\n", argv0, strerror(errno));
  408. 		return 1;
  409. 	}
  411. 	return 0;
  412. }