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utils-std

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

date.c (6853B)

    

  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 <assert.h>
  12. #include <errno.h>
  13. #include <locale.h> /* setlocale() */
  14. #include <stdbool.h>
  15. #include <stdio.h>  /* BUFSIZ, fprintf(), puts() */
  16. #include <stdlib.h> /* exit(), strtol() */
  17. #include <string.h> /* strerror */
  18. #include <time.h>   /* time, localtime, tm, strftime, strptime, clock_settime */
  19. #include <unistd.h> /* getopt(), optarg, optind */
  21. const char *argv0 = "date";
  23. static void
  24. usage(void)
  25. {
  26. 	fprintf(stderr, "\
  27. Usage:\n\
  28. 	date [-jRu] [-d datetime | -r epoch] [+format]\n\
  29. 	date [-jRu] mmddHHMM[[CC]yy] [+format]\n\
  30. 	date [-jRu] -f now_format now [+format]\n\
  31. ");
  32. }
  34. int
  35. main(int argc, char *argv[])
  36. {
  37. 	char outstr[BUFSIZ];
  38. 	struct tm tm = {
  39. 	    .tm_year = 0,
  40. 	    .tm_mon = 0,
  41. 	    .tm_mday = 0,
  42. 	    .tm_hour = 0,
  43. 	    .tm_min = 0,
  44. 	    .tm_sec = 0,
  45. 	    .tm_isdst = -1, // unknown if DST is in effect
  46. 	    .tm_gmtoff = 0,
  47. 	    .tm_zone = NULL,
  48. 	};
  49. 	struct timespec tp = {
  50. 	    .tv_sec = 0,
  51. 	    .tv_nsec = 0,
  52. 	};
  53. 	const char *format = "%c";
  54. 	const char *input_format = NULL;
  55. 	int uflag = 0;
  56. 	int dflag = 0, rflag = 0;
  57. 	int c;
  58. 	bool jflag = false;
  59. 	bool settime = false;
  61. 	errno = 0;
  62. 	setlocale(LC_ALL, "");
  63. 	if(errno != 0)
  64. 	{
  65. 		fprintf(stderr, "%s: warning: Failed to initialize locales: %s\n", argv0, strerror(errno));
  66. 		errno = 0;
  67. 	}
  69. 	tp.tv_sec = time(NULL);
  70. 	if(tp.tv_sec == (time_t)-1)
  71. 	{
  72. 		fprintf(stderr, "%s: error: Failed getting current time: %s\n", argv0, strerror(errno));
  73. 		exit(EXIT_FAILURE);
  74. 	}
  76. 	while((c = getopt(argc, argv, ":d:f:jr:Ru")) != -1)
  77. 	{
  78. 		const char *errstr = NULL;
  79. 		switch(c)
  80. 		{
  81. 		case 'd': /* Custom datetime */
  82. 			if(input_format != NULL)
  83. 			{
  84. 				fprintf(stderr, "%s: error: Cannot both use '-d' and '-f'\n", argv0);
  85. 				exit(EXIT_FAILURE);
  86. 			}
  87. 			if(rflag == 1)
  88. 			{
  89. 				fprintf(stderr, "%s: error: Cannot both use '-d' and '-r'\n", argv0);
  90. 				exit(EXIT_FAILURE);
  91. 			}
  93. 			iso_parse(optarg, &tm, &tp.tv_nsec, &errstr);
  94. 			dflag = 1;
  95. 			if(errstr != NULL)
  96. 			{
  97. 				fprintf(stderr, "%s: error: iso_parse(\"%s\", …): %s\n", argv0, optarg, errstr);
  98. 				exit(EXIT_FAILURE);
  99. 			}
  101. 			assert(errno == 0);
  102. 			tp.tv_sec = mktime_tz(&tm);
  103. 			if(tp.tv_sec == (time_t)-1)
  104. 			{
  105. 				fprintf(stderr, "%s: error: mktime: %s\n", argv0, strerror(errno));
  106. 				exit(EXIT_FAILURE);
  107. 			}
  108. 			errno = 0;
  110. 			break;
  111. 		case 'f': /* input datetime format */
  112. 			if(dflag == 1)
  113. 			{
  114. 				fprintf(stderr, "%s: error: Cannot both use '-d' and '-f'\n", argv0);
  115. 				exit(EXIT_FAILURE);
  116. 			}
  117. 			if(rflag == 1)
  118. 			{
  119. 				fprintf(stderr, "%s: error: Cannot both use '-f' and '-r'\n", argv0);
  120. 				exit(EXIT_FAILURE);
  121. 			}
  123. 			input_format = optarg;
  124. 			settime = true;
  125. 			break;
  126. 		case 'r': /* seconds relative to epoch */
  127. 		{
  128. 			if(input_format != NULL)
  129. 			{
  130. 				fprintf(stderr, "%s: error: Cannot both use '-f' and '-r'\n", argv0);
  131. 				exit(EXIT_FAILURE);
  132. 			}
  133. 			if(dflag == 1)
  134. 			{
  135. 				fprintf(stderr, "%s: error: Cannot both use '-d' and '-r'\n", argv0);
  136. 				exit(EXIT_FAILURE);
  137. 			}
  139. 			char *endptr = NULL;
  140. 			errno = 0;
  141. 			tp.tv_sec = strtol(optarg, &endptr, 10);
  142. 			if(errno != 0)
  143. 			{
  144. 				fprintf(stderr, "%s: error: Failed parsing '-r %s'\n", argv0, optarg);
  145. 				exit(EXIT_FAILURE);
  146. 			}
  147. 			if(!(endptr == NULL || *endptr == '\0'))
  148. 			{
  149. 				fprintf(stderr, "%s: error: Invalid characters in '-r %s': %s\n", argv0, optarg, endptr);
  150. 				exit(EXIT_FAILURE);
  151. 			}
  152. 			break;
  153. 		}
  154. 		case 'R': /* Email (RFC 5322) format */
  155. 			format = "%a, %d %b %Y %H:%M:%S %z";
  156. 			break;
  157. 		case 'u': /* UTC timezone */
  158. 			uflag++;
  159. 			setenv("TZ", "UTC", 1);
  160. 			tzset();
  161. 			break;
  162. 		case 'j':
  163. 			jflag = true;
  164. 			break;
  165. 		case ':':
  166. 			fprintf(stderr, "%s: error: Missing operand for option: '-%c'\n", argv0, optopt);
  167. 			usage();
  168. 			return 1;
  169. 		case '?':
  170. 			fprintf(stderr, "%s: error: Unrecognised option: '-%c'\n", argv0, optopt);
  171. 			usage();
  172. 			return 1;
  173. 		}
  174. 	}
  176. 	argc -= optind;
  177. 	argv += optind;
  179. 	if(uflag)
  180. 	{
  181. 		if(gmtime_r(&tp.tv_sec, &tm) == NULL)
  182. 		{
  183. 			fprintf(stderr, "%s: error: gmtime_r: %s\n", argv0, strerror(errno));
  184. 			exit(EXIT_FAILURE);
  185. 		}
  186. 	}
  187. 	else
  188. 	{
  189. 		if(localtime_r(&tp.tv_sec, &tm) == NULL)
  190. 		{
  191. 			fprintf(stderr, "%s: error: localtime_r: %s\n", argv0, strerror(errno));
  192. 			exit(EXIT_FAILURE);
  193. 		}
  194. 	}
  196. 	if(argc > 0 && input_format != NULL)
  197. 	{
  198. 		char *res = strptime(argv[0], input_format, &tm);
  200. 		if(res == NULL)
  201. 		{
  202. 			fprintf(stderr,
  203. 			        "%s: error: strptime(\"%s\", \"%s\", …) as passed by '-f' option failed\n",
  204. 			        argv0,
  205. 			        argv[0],
  206. 			        input_format);
  207. 			exit(EXIT_FAILURE);
  208. 		}
  210. 		assert(errno == 0);
  211. 		tp.tv_sec = mktime_tz(&tm);
  212. 		tp.tv_nsec = 0;
  213. 		if(tp.tv_sec == (time_t)-1)
  214. 		{
  215. 			fprintf(stderr, "%s: error: mktime: %s\n", argv0, strerror(errno));
  216. 			exit(EXIT_FAILURE);
  217. 		}
  218. 		errno = 0;
  220. 		argv++;
  221. 		argc--;
  222. 	}
  224. 	if(input_format == NULL && argc > 0 && *argv && **argv != '+')
  225. 	{
  226. 		const char *fmt = "%m%d%H%M";
  227. 		char *s = strptime(argv[0], fmt, &tm);
  228. 		if(s == NULL)
  229. 		{
  230. 			fprintf(stderr, "%s: error: strptime(\"%s\", \"%s\", …) returned NULL\n", argv0, *argv, fmt);
  231. 			exit(EXIT_FAILURE);
  232. 		}
  234. 		size_t rem = strlen(s);
  235. 		if(rem > 0)
  236. 		{
  237. 			switch(rem)
  238. 			{
  239. 			case 2:
  240. 				fmt = "%y";
  241. 				break;
  242. 			case 4:
  243. 				fmt = "%Y";
  244. 				break;
  245. 			default:
  246. 				fprintf(stderr,
  247. 				        "%s: error: Got %zu trailing characters after \"%s\" for mmddHHMM\n",
  248. 				        argv0,
  249. 				        rem,
  250. 				        fmt);
  251. 				exit(EXIT_FAILURE);
  252. 			}
  254. 			s = strptime(s, fmt, &tm);
  255. 			if(s == NULL)
  256. 			{
  257. 				fprintf(
  258. 				    stderr, "%s: error: strptime(\"%s\", \"%s\", …) returned NULL\n", argv0, *argv, fmt);
  259. 				exit(EXIT_FAILURE);
  260. 			}
  261. 		}
  263. 		assert(errno == 0);
  264. 		tp.tv_sec = mktime(&tm);
  265. 		tp.tv_nsec = 0;
  266. 		if(tp.tv_sec == (time_t)-1)
  267. 		{
  268. 			fprintf(stderr, "%s: error: mktime: %s\n", argv0, strerror(errno));
  269. 			exit(EXIT_FAILURE);
  270. 		}
  271. 		errno = 0;
  273. 		argv++;
  274. 		argc--;
  275. 		settime = true;
  276. 	}
  278. 	if(settime && !jflag)
  279. 	{
  280. 		if(clock_settime(CLOCK_REALTIME, &tp) != 0)
  281. 		{
  282. 			fprintf(stderr,
  283. 			        "%s: error: clock_settime(CLOCK_REALTIME, {%ld, %ld}): %s\n",
  284. 			        argv0,
  285. 			        tp.tv_sec,
  286. 			        tp.tv_nsec,
  287. 			        strerror(errno));
  288. 			exit(EXIT_FAILURE);
  289. 		}
  290. 	}
  292. 	if(argc > 0 && *argv && **argv == '+')
  293. 	{
  294. 		format = *argv + 1;
  296. 		argv++;
  297. 		argc--;
  298. 	}
  300. 	errno = 0;
  301. 	if(strftime(outstr, sizeof(outstr), format, &tm) == 0 && errno != 0)
  302. 	{
  303. 		fprintf(stderr, "%s: error: Failed formatting time: %s\n", argv0, strerror(errno));
  304. 		exit(EXIT_FAILURE);
  305. 	}
  307. 	if(puts(outstr) < 0)
  308. 	{
  309. 		fprintf(stderr, "%s: error: Failed writing time: %s\n", argv0, strerror(errno));
  310. 		exit(EXIT_FAILURE);
  311. 	}
  313. 	return 0;
  314. }