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utils-std

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

env.c (4226B)

    

  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 _POSIX_C_SOURCE 200809L
  6. #define _XOPEN_SOURCE 800 // wordexp
  8. #include "../config.h" // HAS_*
  9. #include "../libutils/getopt_nolong.h"
  11. #include <assert.h>  // assert
  12. #include <errno.h>   // errno
  13. #include <stdbool.h> // bool, true, false
  14. #include <stdio.h>   // puts, fprintf
  15. #include <stdlib.h>  // putenv
  16. #include <string.h>  // strchr, strerror
  17. #include <unistd.h>  // getopt, opt*
  18. #ifdef HAS_WORDEXP
  19. #include <wordexp.h>
  20. #endif
  21. #ifdef HAS_GETOPT_LONG
  22. #include <getopt.h>
  23. #endif
  25. const char *argv0 = "env";
  27. extern char **environ;
  28. char *envclear[1];
  30. static int
  31. do_export(void)
  32. {
  33. 	int i = 0;
  35. 	for(; environ[i] != NULL; i++)
  36. 	{
  37. 		if(puts(environ[i]) < 0)
  38. 		{
  39. 			fprintf(stderr, "env: error: Failed writing environ: %s\n", strerror(errno));
  40. 			return 1;
  41. 		}
  42. 	}
  44. 	return 0;
  45. }
  47. static void
  48. usage(void)
  49. {
  50. 	fprintf(stderr, "env [-i] [-u key] [key=value ...] [command [args]]\n");
  51. }
  53. int
  54. main(int argc, char *argv[])
  55. {
  56. 	const char *newdir = NULL;
  57. 	bool flag_i = false;
  58. #ifdef HAS_WORDEXP
  59. 	bool flag_S = false;
  60. 	wordexp_t opt_S;
  61. #define OPTARGS ":C:iu:S:"
  62. #else
  63. #define OPTARGS ":C:iu:"
  64. #endif
  66. #ifdef HAS_GETOPT_LONG
  67. 	// Strictly for GNUisms compatibility so no long-only options
  68. 	// clang-format off
  69. 	static struct option opts[] = {
  70. 		{"ignore-environment", no_argument, NULL, 'i'},
  71. 		{"unset", required_argument, NULL, 'u'},
  72. 		{"chdir", required_argument, NULL, 'C'},
  73. #ifdef HAS_WORDEXP
  74. 		{"split-string", required_argument, NULL, 'S'},
  75. #endif
  76. 		{0, 0, 0, 0},
  77. 	};
  78. 	// clang-format on
  80. 	// Need + as first character to get POSIX-style option parsing
  81. 	for(int c = -1; (c = getopt_long(argc, argv, "+" OPTARGS, opts, NULL)) != -1;)
  82. #else
  83. 	for(int c = -1; (c = getopt_nolong(argc, argv, OPTARGS)) != -1;)
  84. #endif
  85. 	{
  86. 		switch(c)
  87. 		{
  88. 		case 'C':
  89. 			newdir = optarg;
  90. 			break;
  91. 		case 'i':
  92. 			flag_i = true;
  93. 			break;
  94. 		case 'u':
  95. 			unsetenv(optarg);
  96. 			break;
  97. #ifdef HAS_WORDEXP
  98. 		case 'S':
  99. 			flag_S = true;
  100. 			int ret = wordexp(optarg, &opt_S, WRDE_NOCMD);
  101. 			switch(ret)
  102. 			{
  103. 			case 0:
  104. 				break;
  105. 			case WRDE_BADCHAR:
  106. 				fputs("env: error: wordexpr returned WRDE_BADCHAR\n", stderr);
  107. 				return 1;
  108. 			case WRDE_BADVAL:
  109. 				fputs("env: error: Undefined shell variable (WRDE_BADVAL)\n", stderr);
  110. 				return 1;
  111. 			case WRDE_CMDSUB:
  112. 				fputs("env: error: Command substitution forbidden (WRDE_CMDSUB)\n", stderr);
  113. 				return 1;
  114. 			case WRDE_NOSPACE:
  115. 				fputs("env: error: Out of memory (WRDE_NOSPACE)\n", stderr);
  116. 				return 1;
  117. 			case WRDE_SYNTAX:
  118. 				fputs("env: error: Syntax Error (WRDE_SYNTAX)\n", stderr);
  119. 				return 1;
  120. 			default:
  121. 				fprintf(stderr, "env: error: Unknown error %d from wordexp\n", ret);
  122. 				return 1;
  123. 			}
  124. 			break;
  125. #endif
  126. 		case ':':
  127. 			fprintf(stderr, "env: error: Missing operand for option: '-%c'\n", optopt);
  128. 			usage();
  129. 			return 1;
  130. 		case '?':
  131. 			GETOPT_UNKNOWN_OPT
  132. 			usage();
  133. 			return 1;
  134. 		default:
  135. 			assert(false);
  136. 		}
  137. 	}
  139. 	argc -= optind;
  140. 	argv += optind;
  142. 	if(flag_i)
  143. 	{
  144. 		environ = envclear;
  145. 		envclear[0] = NULL;
  146. 	}
  148. 	for(; argv[0]; argv++, argc--)
  149. 	{
  150. 		char *sep = strchr(argv[0], '=');
  151. 		if(sep == NULL)
  152. 		{
  153. 			break;
  154. 		}
  156. 		*sep = 0;
  157. 		sep++;
  159. 		if(setenv(argv[0], sep, 1))
  160. 		{
  161. 			fprintf(stderr,
  162. 			        "env: error: Failed setting environment variable '%s' to '%s': %s\n",
  163. 			        argv[0],
  164. 			        sep,
  165. 			        strerror(errno));
  166. 			return 1;
  167. 		}
  168. 	}
  170. 	if(newdir && chdir(newdir) != 0)
  171. 	{
  172. 		fprintf(stderr,
  173. 		        "env: error: Failed changing workding directory into '%s': %s\n",
  174. 		        newdir,
  175. 		        strerror(errno));
  176. 		return 1;
  177. 	}
  179. #ifdef HAS_WORDEXP
  180. 	if(flag_S)
  181. 	{
  182. 		errno = 0;
  183. 		if(execvp(opt_S.we_wordv[0], opt_S.we_wordv) < 0)
  184. 		{
  185. 			fprintf(
  186. 			    stderr, "env: error: Failed executing '%s': %s\n", opt_S.we_wordv[0], strerror(errno));
  188. 			return (errno == ENOENT) ? 127 : 126;
  189. 		}
  190. 		assert(false);
  191. 	}
  192. #endif
  194. 	if(argc < 1)
  195. 	{
  196. 		return do_export();
  197. 	}
  199. 	assert(argv[0]);
  200. 	errno = 0;
  201. 	if(execvp(argv[0], argv) < 0)
  202. 	{
  203. 		fprintf(stderr, "env: error: Failed executing '%s': %s\n", argv[0], strerror(errno));
  205. 		return (errno == ENOENT) ? 127 : 126;
  206. 	}
  208. 	assert(false);
  209. }