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utils-std

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

env.c (3970B)

    

  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 "../lib/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. 	bool flag_i = false;
  57. #ifdef HAS_WORDEXP
  58. 	bool flag_S = false;
  59. 	wordexp_t opt_S;
  60. #define OPTARGS ":iu:S:"
  61. #else
  62. #define OPTARGS ":iu:"
  63. #endif
  65. #ifdef HAS_GETOPT_LONG
  66. 	// Strictly for GNUisms compatibility so no long-only options
  67. 	// clang-format off
  68. 	static struct option opts[] = {
  69. 		{"ignore-environment", no_argument, 0, 'i'},
  70. 		{"unset", required_argument, 0, 'u'},
  71. #ifdef HAS_WORDEXP
  72. 		{"split-string", required_argument, 0, 'S'},
  73. #endif
  74. 		{0, 0, 0, 0},
  75. 	};
  76. 	// clang-format on
  78. 	// Need + as first character to get POSIX-style option parsing
  79. 	for(int c = -1; (c = getopt_long(argc, argv, "+" OPTARGS, opts, NULL)) != -1;)
  80. #else
  81. 	for(int c = -1; (c = getopt_nolong(argc, argv, OPTARGS)) != -1;)
  82. #endif
  83. 	{
  84. 		switch(c)
  85. 		{
  86. 		case 'i':
  87. 			flag_i = true;
  88. 			break;
  89. 		case 'u':
  90. 			unsetenv(optarg);
  91. 			break;
  92. #ifdef HAS_WORDEXP
  93. 		case 'S':
  94. 			flag_S = true;
  95. 			int ret = wordexp(optarg, &opt_S, WRDE_NOCMD);
  96. 			switch(ret)
  97. 			{
  98. 			case 0:
  99. 				break;
  100. 			case WRDE_BADCHAR:
  101. 				fputs("env: error: wordexpr returned WRDE_BADCHAR\n", stderr);
  102. 				return 1;
  103. 			case WRDE_BADVAL:
  104. 				fputs("env: error: Undefined shell variable (WRDE_BADVAL)\n", stderr);
  105. 				return 1;
  106. 			case WRDE_CMDSUB:
  107. 				fputs("env: error: Command substitution forbidden (WRDE_CMDSUB)\n", stderr);
  108. 				return 1;
  109. 			case WRDE_NOSPACE:
  110. 				fputs("env: error: Out of memory (WRDE_NOSPACE)\n", stderr);
  111. 				return 1;
  112. 			case WRDE_SYNTAX:
  113. 				fputs("env: error: Syntax Error (WRDE_SYNTAX)\n", stderr);
  114. 				return 1;
  115. 			default:
  116. 				fprintf(stderr, "env: error: Unknown error %d from wordexp\n", ret);
  117. 				return 1;
  118. 			}
  119. 			break;
  120. #endif
  121. 		case ':':
  122. 			fprintf(stderr, "env: error: Missing operand for option: '-%c'\n", optopt);
  123. 			usage();
  124. 			return 1;
  125. 		case '?':
  126. 			if(!got_long_opt) fprintf(stderr, "env: error: Unrecognised option: '-%c'\n", optopt);
  127. 			usage();
  128. 			return 1;
  129. 		default:
  130. 			assert(false);
  131. 		}
  132. 	}
  134. 	argc -= optind;
  135. 	argv += optind;
  137. 	if(flag_i)
  138. 	{
  139. 		environ = envclear;
  140. 		envclear[0] = NULL;
  141. 	}
  143. 	for(; argv[0]; argv++, argc--)
  144. 	{
  145. 		char *sep = strchr(argv[0], '=');
  146. 		if(sep == NULL)
  147. 		{
  148. 			break;
  149. 		}
  151. 		*sep = 0;
  152. 		sep++;
  154. 		if(setenv(argv[0], sep, 1))
  155. 		{
  156. 			fprintf(stderr,
  157. 			        "env: error: Failed setting environment variable '%s' to '%s': %s\n",
  158. 			        argv[0],
  159. 			        sep,
  160. 			        strerror(errno));
  161. 			return 1;
  162. 		}
  163. 	}
  165. #ifdef HAS_WORDEXP
  166. 	if(flag_S)
  167. 	{
  168. 		errno = 0;
  169. 		if(execvp(opt_S.we_wordv[0], opt_S.we_wordv) < 0)
  170. 		{
  171. 			fprintf(
  172. 			    stderr, "env: error: Failed executing '%s': %s\n", opt_S.we_wordv[0], strerror(errno));
  174. 			return (errno == ENOENT) ? 127 : 126;
  175. 		}
  176. 		assert(false);
  177. 	}
  178. #endif
  180. 	if(argc < 1)
  181. 	{
  182. 		return do_export();
  183. 	}
  185. 	assert(argv[0]);
  186. 	errno = 0;
  187. 	if(execvp(argv[0], argv) < 0)
  188. 	{
  189. 		fprintf(stderr, "env: error: Failed executing '%s': %s\n", argv[0], strerror(errno));
  191. 		return (errno == ENOENT) ? 127 : 126;
  192. 	}
  194. 	assert(false);
  195. }