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utils-std

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

base64.c (6934B)

    

  1. // utils-std: Collection of commonly available Unix tools
  2. // SPDX-FileCopyrightText: 2017 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
  3. // SPDX-FileCopyrightText: 2018 The NetBSD Foundation, Inc.
  4. // SPDX-License-Identifier: MPL-2.0 AND BSD-2-Clause
  6. #define _POSIX_C_SOURCE 200809L
  7. #include <assert.h> /* assert */
  8. #include <ctype.h>  /* isspace */
  9. #include <errno.h>  /* errno */
  10. #include <stdint.h> /* uint8_t */
  11. #include <stdio.h>  /* fopen(), fprintf(), BUFSIZ */
  12. #include <stdlib.h> /* abort */
  13. #include <string.h> /* strerror(), strncmp() */
  14. #include <unistd.h> /* read(), write(), close(), getopt(), opt* */
  16. // 64(26+26+10+2) + NULL
  17. static const char *b64_encmap = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  18. static size_t c_out = 0;
  19. // 76 is lowest of all base64 related RFCs
  20. static long wrap_nl = 76;
  21. const char *argv0 = "base64";
  23. static int
  24. xputc(int c, FILE *stream)
  25. {
  26. 	if(fputc(c, stream) == EOF)
  27. 	{
  28. 		fprintf(stderr, "%s: error: Failed writing: %s\n", argv0, strerror(errno));
  29. 		errno = 0;
  30. 		return 1;
  31. 	}
  33. 	int err = ferror(stream);
  34. 	if(err != 0)
  35. 	{
  36. 		fprintf(stderr, "%s: error: Failed writing: %s\n", argv0, strerror(err));
  37. 		errno = 0;
  38. 		return 1;
  39. 	}
  41. 	return 0;
  42. }
  44. static inline uint8_t
  45. b64_get(uint8_t pos)
  46. {
  47. 	assert(pos <= 64);
  48. 	return b64_encmap[pos];
  49. }
  51. static void
  52. b64encode(uint8_t out[4], uint8_t in[3])
  53. {
  54. 	out[0] = b64_get(in[0] >> 2);
  55. 	out[1] = b64_get((uint8_t)(((in[0] & 0x03) << 4) | (in[1] >> 4)));
  56. 	out[2] = b64_get((uint8_t)(((in[1] & 0x0f) << 2) | (in[2] >> 6)));
  57. 	out[3] = b64_get(in[2] & 0x3f);
  58. }
  60. static int
  61. encode(FILE *fin, const char *name)
  62. {
  63. 	while(1)
  64. 	{
  65. 		uint8_t obuf[4] = "----";
  66. 		uint8_t ibuf[3] = {0, 0, 0};
  67. 		uint8_t pad = 0;
  69. 		size_t c = 0;
  70. 		for(; c < 3; c++)
  71. 		{
  72. 			int buf = getc(fin);
  73. 			if(buf == EOF)
  74. 			{
  75. 				break;
  76. 			}
  77. 			ibuf[c] = buf;
  78. 		}
  79. 		if(c == 0)
  80. 		{
  81. 			return 0;
  82. 		};
  83. 		if(ferror(fin))
  84. 		{
  85. 			fprintf(
  86. 			    stderr, "%s: error: Failed reading from file '%s': %s\n", argv0, name, strerror(errno));
  87. 			errno = 0;
  88. 			return 1;
  89. 		}
  90. 		for(; c < 3; pad++, c++)
  91. 		{
  92. 			ibuf[c] = 0;
  93. 		}
  94. 		assert(c == 3);
  95. 		assert(pad <= 3);
  97. 		b64encode(obuf, (uint8_t *)ibuf);
  99. 		for(; pad > 0; pad--)
  100. 		{
  101. 			obuf[4 - pad] = '=';
  102. 		}
  104. 		if(fwrite((char *)obuf, 4, 1, stdout) <= 0)
  105. 		{
  106. 			fprintf(stderr, "%s: error: Failed writing: %s\n", argv0, strerror(errno));
  107. 			errno = 0;
  108. 			return 1;
  109. 		}
  110. 		c_out += 4;
  112. 		if(wrap_nl != 0 && (c_out + 4) > wrap_nl)
  113. 		{
  114. 			c_out = 0;
  115. 			if(xputc('\n', stdout) != 0) return 1;
  116. 		}
  118. 		if(feof(fin))
  119. 		{
  120. 			if(fflush(stdout))
  121. 			{
  122. 				fprintf(stderr, "%s: error: Failed writing: %s\n", argv0, strerror(errno));
  123. 				errno = 0;
  124. 				return 1;
  125. 			}
  126. 			int err = ferror(stdout);
  127. 			if(err != 0)
  128. 			{
  129. 				fprintf(stderr, "%s: error: Failed writing: %s\n", argv0, strerror(errno));
  130. 				return 1;
  131. 			}
  133. 			return 0;
  134. 		}
  135. 	}
  137. 	abort(); // unreachable
  138. }
  140. // This function is based on NetBSD's code, which contains the following notices:
  141. // Copyright (c) 2018 The NetBSD Foundation, Inc.
  142. //
  143. // This code is derived from software contributed to The NetBSD Foundation
  144. // by Christos Zoulas.
  145. static int
  146. decode(FILE *fin, const char *name)
  147. {
  148. 	int c = 0;
  149. 	uint8_t out = 0;
  150. 	int state = 0;
  152. 	while((c = getc(fin)) != EOF)
  153. 	{
  154. 		if(isspace(c)) continue;
  156. 		if(c == '=') break;
  158. 		uint8_t b = 65;
  159. 		for(uint8_t i = 0; i < 64; i++)
  160. 		{
  161. 			if(b64_encmap[i] == c)
  162. 			{
  163. 				b = i;
  164. 				break;
  165. 			}
  166. 		}
  167. 		if(b > 64)
  168. 		{
  169. 			fprintf(stderr, "%s: error: Invalid character '%c'\n", argv0, c);
  170. 			return 1;
  171. 		}
  173. 		//fprintf(stderr, "state: %d | c: %c (%d) | b: %d\n", state, c, c, b);
  175. 		switch(state)
  176. 		{
  177. 		case 0:
  178. 			out = (uint8_t)(b << 2);
  179. 			break;
  180. 		case 1:
  181. 			out |= b >> 4;
  182. 			if(xputc(out, stdout) != 0) return 1;
  183. 			out = (uint8_t)((b & 0xf) << 4);
  184. 			break;
  185. 		case 2:
  186. 			out |= b >> 2;
  187. 			if(xputc(out, stdout) != 0) return 1;
  188. 			out = (uint8_t)((b & 0x3) << 6);
  189. 			break;
  190. 		case 3:
  191. 			out |= b;
  192. 			if(xputc(out, stdout) != 0) return 1;
  193. 			out = 0;
  194. 			break;
  195. 		default:
  196. 			abort();
  197. 		}
  198. 		state = (state + 1) & 3;
  199. 	}
  201. 	//fprintf(stderr, "[outside] state: %d | c: %c (%d) | out: %d\n", state, c, c, out);
  203. 	if(c == '=')
  204. 	{
  205. 		switch(state)
  206. 		{
  207. 		case 0:
  208. 		case 1:
  209. 			fprintf(stderr, "%s: error: Invalid character '%c' (early '=')\n", argv0, c);
  210. 			return 1;
  211. 		case 2:
  212. 			while(isspace(c = getc(fin)))
  213. 				;
  215. 			if(c != '=')
  216. 			{
  217. 				fprintf(stderr, "%s: error: Invalid character '%c' (not '=')\n", argv0, c);
  218. 				return 1;
  219. 			}
  220. 			/* fallthrough */
  221. 		case 3:
  222. 			while(isspace(c = getc(fin)))
  223. 				;
  225. 			if(c != EOF)
  226. 			{
  227. 				fprintf(stderr, "%s: error: Invalid character '%c' (not EOF)\n", argv0, c);
  228. 				return 1;
  229. 			}
  230. 			return 0;
  231. 		default:
  232. 			abort();
  233. 		}
  234. 	}
  236. 	assert(c == EOF || state == 0);
  238. 	if(fflush(stdout))
  239. 	{
  240. 		fprintf(stderr, "%s: error: Failed writing: %s\n", argv0, strerror(errno));
  241. 		errno = 0;
  242. 		return 1;
  243. 	}
  244. 	int err = ferror(stdout);
  245. 	if(err != 0)
  246. 	{
  247. 		fprintf(stderr, "%s: error: Failed writing: %s\n", argv0, strerror(err));
  248. 		errno = 0;
  249. 		return 1;
  250. 	}
  252. 	return 0;
  253. }
  255. int
  256. main(int argc, char *argv[])
  257. {
  258. 	int (*process)(FILE *, const char *) = &encode;
  260. 	int c = 0, ret = 0;
  262. 	while((c = getopt(argc, argv, ":dw:")) != -1)
  263. 	{
  264. 		switch(c)
  265. 		{
  266. 		case 'd':
  267. 			process = &decode;
  268. 			break;
  269. 		case 'w':
  270. 			errno = 0;
  271. 			char *e = NULL;
  272. 			wrap_nl = strtol(optarg, &e, 10);
  274. 			// extraneous characters is invalid
  275. 			if(e && *e != 0) errno = EINVAL;
  277. 			if(errno != 0)
  278. 			{
  279. 				fprintf(stderr, "%s: error: Option '-w %s': %s\n", argv0, optarg, strerror(errno));
  280. 				return 1;
  281. 			}
  282. 			break;
  283. 		case ':':
  284. 			fprintf(stderr, "%s: error: Missing operand for option '-%c'\n", argv0, optopt);
  285. 			return 1;
  286. 		case '?':
  287. 			fprintf(stderr, "%s: error: Unrecognised option '-%c'\n", argv0, optopt);
  288. 			return 1;
  289. 		}
  290. 	}
  292. 	argc -= optind;
  293. 	argv += optind;
  295. 	if(argc <= 0)
  296. 	{
  297. 		ret = process(stdin, "<stdin>");
  298. 		goto end;
  299. 	}
  301. 	for(int argi = 0; argi < argc; argi++)
  302. 	{
  303. 		if(strncmp(argv[argi], "-", 2) == 0)
  304. 		{
  305. 			if(process(stdin, "<stdin>") != 0)
  306. 			{
  307. 				ret = 1;
  308. 				goto end;
  309. 			}
  310. 		}
  311. 		else if(strncmp(argv[argi], "--", 3) == 0)
  312. 		{
  313. 			continue;
  314. 		}
  315. 		else
  316. 		{
  317. 			FILE *fin = fopen(argv[argi], "r");
  318. 			if(fin == NULL || ferror(fin) != 0)
  319. 			{
  320. 				fprintf(stderr,
  321. 				        "%s: error: Failed opening file '%s': %s\n",
  322. 				        argv0,
  323. 				        argv[argi],
  324. 				        strerror(errno));
  325. 				ret = 1;
  326. 				goto end;
  327. 			}
  329. 			if(process(fin, argv[argi]) != 0) ret = 1;
  331. 			if(fclose(fin) < 0)
  332. 			{
  333. 				fprintf(stderr,
  334. 				        "%s: error: Failed closing file '%s': %s\n",
  335. 				        argv0,
  336. 				        argv[argi],
  337. 				        strerror(errno));
  338. 				ret = 1;
  339. 				goto end;
  340. 			}
  341. 		}
  342. 	}
  344. end:
  345. 	if(wrap_nl != 0 && c_out > 0)
  346. 	{
  347. 		printf("\n");
  348. 	}
  350. 	if(fclose(stdin) != 0)
  351. 	{
  352. 		fprintf(stderr, "%s: error: Failed closing file <stdin>: %s\n", argv0, strerror(errno));
  353. 		ret = 1;
  354. 	}
  356. 	if(fclose(stdout) != 0)
  357. 	{
  358. 		fprintf(stderr, "%s: error: Failed closing file <stdout>: %s\n", argv0, strerror(errno));
  359. 		ret = 1;
  360. 	}
  362. 	return ret;
  363. }