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utils-std

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

date.c (6412B)

    

  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/iso_parse.h" /* iso_parse */
  11. #include <errno.h>
  12. #include <locale.h> /* setlocale() */
  13. #include <stdbool.h>
  14. #include <stdio.h>  /* BUFSIZ, fprintf(), puts() */
  15. #include <stdlib.h> /* strtol() */
  16. #include <string.h> /* strerror */
  17. #include <time.h>   /* time, localtime, tm, strftime, strptime, clock_settime */
  18. #include <unistd.h> /* getopt(), optarg, optind */
  20. const char *argv0 = "date";
  22. static void
  23. usage(void)
  24. {
  25. 	fprintf(stderr, "\
  26. Usage:\n\
  27. 	date [-jRu] [-d datetime | -r epoch] [+format]\n\
  28. 	date [-jRu] mmddHHMM[[CC]yy] [+format]\n\
  29. 	date [-jRu] -f now_format now [+format]\n\
  30. ");
  31. }
  33. int
  34. main(int argc, char *argv[])
  35. {
  36. 	char outstr[BUFSIZ];
  37. 	struct tm tm = {
  38. 	    .tm_year = 0,
  39. 	    .tm_mon = 0,
  40. 	    .tm_mday = 0,
  41. 	    .tm_hour = 0,
  42. 	    .tm_min = 0,
  43. 	    .tm_sec = 0,
  44. 	    .tm_isdst = -1, // unknown if DST is in effect
  45. 	    .tm_gmtoff = 0,
  46. 	    .tm_zone = NULL,
  47. 	};
  48. 	struct timespec tp = {
  49. 	    .tv_sec = 0,
  50. 	    .tv_nsec = 0,
  51. 	};
  52. 	const char *format = "%c";
  53. 	const char *input_format = NULL;
  54. 	int uflag = 0;
  55. 	int dflag = 0, rflag = 0;
  56. 	bool jflag = false;
  57. 	bool settime = false;
  59. 	setlocale(LC_ALL, "");
  60. 	errno = 0;
  62. 	tp.tv_sec = time(NULL);
  63. 	if(tp.tv_sec == (time_t)-1)
  64. 	{
  65. 		fprintf(stderr, "%s: error: Failed getting current time: %s\n", argv0, strerror(errno));
  66. 		return 1;
  67. 	}
  69. 	for(int c = -1; (c = getopt(argc, argv, ":d:f:jr:Ru")) != -1;)
  70. 	{
  71. 		const char *errstr = NULL;
  72. 		switch(c)
  73. 		{
  74. 		case 'd': /* Custom datetime */
  75. 			if(input_format != NULL)
  76. 			{
  77. 				fprintf(stderr, "%s: error: Cannot both use '-d' and '-f'\n", argv0);
  78. 				return 1;
  79. 			}
  80. 			if(rflag == 1)
  81. 			{
  82. 				fprintf(stderr, "%s: error: Cannot both use '-d' and '-r'\n", argv0);
  83. 				return 1;
  84. 			}
  86. 			iso_parse(optarg, &tm, &tp.tv_nsec, &errstr);
  87. 			dflag = 1;
  88. 			if(errstr != NULL)
  89. 			{
  90. 				fprintf(stderr, "%s: error: iso_parse(\"%s\", …): %s\n", argv0, optarg, errstr);
  91. 				return 1;
  92. 			}
  94. 			tp.tv_sec = mktime_tz(&tm);
  95. 			if(tp.tv_sec == (time_t)-1)
  96. 			{
  97. 				fprintf(stderr, "%s: error: mktime: %s\n", argv0, strerror(errno));
  98. 				return 1;
  99. 			}
  100. 			errno = 0;
  102. 			break;
  103. 		case 'f': /* input datetime format */
  104. 			if(dflag == 1)
  105. 			{
  106. 				fprintf(stderr, "%s: error: Cannot both use '-d' and '-f'\n", argv0);
  107. 				return 1;
  108. 			}
  109. 			if(rflag == 1)
  110. 			{
  111. 				fprintf(stderr, "%s: error: Cannot both use '-f' and '-r'\n", argv0);
  112. 				return 1;
  113. 			}
  115. 			input_format = optarg;
  116. 			settime = true;
  117. 			break;
  118. 		case 'r': /* seconds relative to epoch */
  119. 		{
  120. 			if(input_format != NULL)
  121. 			{
  122. 				fprintf(stderr, "%s: error: Cannot both use '-f' and '-r'\n", argv0);
  123. 				return 1;
  124. 			}
  125. 			if(dflag == 1)
  126. 			{
  127. 				fprintf(stderr, "%s: error: Cannot both use '-d' and '-r'\n", argv0);
  128. 				return 1;
  129. 			}
  131. 			char *endptr = NULL;
  132. 			errno = 0;
  133. 			tp.tv_sec = strtol(optarg, &endptr, 10);
  134. 			if(errno != 0)
  135. 			{
  136. 				fprintf(stderr, "%s: error: Failed parsing '-r %s'\n", argv0, optarg);
  137. 				return 1;
  138. 			}
  139. 			if(!(endptr == NULL || *endptr == '\0'))
  140. 			{
  141. 				fprintf(stderr, "%s: error: Invalid characters in '-r %s': %s\n", argv0, optarg, endptr);
  142. 				return 1;
  143. 			}
  144. 			break;
  145. 		}
  146. 		case 'R': /* Email (RFC 5322) format */
  147. 			format = "%a, %d %b %Y %H:%M:%S %z";
  148. 			break;
  149. 		case 'u': /* UTC timezone */
  150. 			uflag++;
  151. 			setenv("TZ", "UTC", 1);
  152. 			tzset();
  153. 			break;
  154. 		case 'j':
  155. 			jflag = true;
  156. 			break;
  157. 		case ':':
  158. 			fprintf(stderr, "%s: error: Missing operand for option: '-%c'\n", argv0, optopt);
  159. 			usage();
  160. 			return 1;
  161. 		case '?':
  162. 			fprintf(stderr, "%s: error: Unrecognised option: '-%c'\n", argv0, optopt);
  163. 			usage();
  164. 			return 1;
  165. 		}
  166. 	}
  168. 	argc -= optind;
  169. 	argv += optind;
  171. 	if(uflag)
  172. 	{
  173. 		if(gmtime_r(&tp.tv_sec, &tm) == NULL)
  174. 		{
  175. 			fprintf(stderr, "%s: error: gmtime_r: %s\n", argv0, strerror(errno));
  176. 			return 1;
  177. 		}
  178. 	}
  179. 	else
  180. 	{
  181. 		if(localtime_r(&tp.tv_sec, &tm) == NULL)
  182. 		{
  183. 			fprintf(stderr, "%s: error: localtime_r: %s\n", argv0, strerror(errno));
  184. 			return 1;
  185. 		}
  186. 	}
  188. 	if(argc > 0 && input_format != NULL)
  189. 	{
  190. 		char *res = strptime(argv[0], input_format, &tm);
  192. 		if(res == NULL)
  193. 		{
  194. 			fprintf(stderr,
  195. 			        "%s: error: strptime(\"%s\", \"%s\", …) as passed by '-f' option failed\n",
  196. 			        argv0,
  197. 			        argv[0],
  198. 			        input_format);
  199. 			return 1;
  200. 		}
  202. 		tp.tv_sec = mktime_tz(&tm);
  203. 		tp.tv_nsec = 0;
  204. 		if(tp.tv_sec == (time_t)-1)
  205. 		{
  206. 			fprintf(stderr, "%s: error: mktime: %s\n", argv0, strerror(errno));
  207. 			return 1;
  208. 		}
  209. 		errno = 0;
  211. 		argv++;
  212. 		argc--;
  213. 	}
  215. 	if(input_format == NULL && argc > 0 && *argv && **argv != '+')
  216. 	{
  217. 		const char *fmt = "%m%d%H%M";
  218. 		char *s = strptime(argv[0], fmt, &tm);
  219. 		if(s == NULL)
  220. 		{
  221. 			fprintf(stderr, "%s: error: strptime(\"%s\", \"%s\", …) returned NULL\n", argv0, *argv, fmt);
  222. 			return 1;
  223. 		}
  225. 		size_t rem = strlen(s);
  226. 		if(rem > 0)
  227. 		{
  228. 			switch(rem)
  229. 			{
  230. 			case 2:
  231. 				fmt = "%y";
  232. 				break;
  233. 			case 4:
  234. 				fmt = "%Y";
  235. 				break;
  236. 			default:
  237. 				fprintf(stderr,
  238. 				        "%s: error: Got %zu trailing characters after \"%s\" for mmddHHMM\n",
  239. 				        argv0,
  240. 				        rem,
  241. 				        fmt);
  242. 				return 1;
  243. 			}
  245. 			s = strptime(s, fmt, &tm);
  246. 			if(s == NULL)
  247. 			{
  248. 				fprintf(
  249. 				    stderr, "%s: error: strptime(\"%s\", \"%s\", …) returned NULL\n", argv0, *argv, fmt);
  250. 				return 1;
  251. 			}
  252. 		}
  254. 		tp.tv_sec = mktime(&tm);
  255. 		tp.tv_nsec = 0;
  256. 		if(tp.tv_sec == (time_t)-1)
  257. 		{
  258. 			fprintf(stderr, "%s: error: mktime: %s\n", argv0, strerror(errno));
  259. 			return 1;
  260. 		}
  261. 		errno = 0;
  263. 		argv++;
  264. 		argc--;
  265. 		settime = true;
  266. 	}
  268. 	if(settime && !jflag)
  269. 	{
  270. 		if(clock_settime(CLOCK_REALTIME, &tp) != 0)
  271. 		{
  272. 			fprintf(stderr,
  273. 			        "%s: error: clock_settime(CLOCK_REALTIME, {%ld, %ld}): %s\n",
  274. 			        argv0,
  275. 			        tp.tv_sec,
  276. 			        tp.tv_nsec,
  277. 			        strerror(errno));
  278. 			return 1;
  279. 		}
  280. 	}
  282. 	if(argc > 0 && *argv && **argv == '+')
  283. 	{
  284. 		format = *argv + 1;
  286. 		argv++;
  287. 		argc--;
  288. 	}
  290. 	errno = 0;
  291. 	if(strftime(outstr, sizeof(outstr), format, &tm) == 0 && errno != 0)
  292. 	{
  293. 		fprintf(stderr, "%s: error: Failed formatting time: %s\n", argv0, strerror(errno));
  294. 		return 1;
  295. 	}
  297. 	if(puts(outstr) < 0)
  298. 	{
  299. 		fprintf(stderr, "%s: error: Failed writing time: %s\n", argv0, strerror(errno));
  300. 		return 1;
  301. 	}
  303. 	return 0;
  304. }