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~/.local/bin tools and git-hooks git clone https://hacktivis.me/git/utils.git

env.c (2366B)

    

  1. // Collection of Unix tools, comparable to coreutils
  2. // SPDX-FileCopyrightText: 2017-2023 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
  3. // SPDX-License-Identifier: MPL-2.0
  5. #define _POSIX_C_SOURCE 200809L
  6. #include <assert.h>  // assert
  7. #include <errno.h>   // errno
  8. #include <stdbool.h> // bool, true, false
  9. #include <stdio.h>   // puts, fprintf
  10. #include <stdlib.h>  // putenv
  11. #include <string.h>  // strchr, strerror
  12. #include <unistd.h>  // getopt, opt*
  14. extern char **environ;
  15. char *envclear[1];
  17. int export()
  18. {
  19. 	int i = 0;
  21. 	for(; environ[i] != NULL; i++)
  22. 	{
  23. 		if(puts(environ[i]) < 0)
  24. 		{
  25. 			perror("env: puts(environ[i])");
  26. 			return 1;
  27. 		}
  28. 	}
  30. 	return 0;
  31. }
  33. void
  34. usage()
  35. {
  36. 	fprintf(stderr, "env [-i] [-u key | --unset=key] [key=value ...] [command [args]]\n");
  37. }
  39. int
  40. main(int argc, char *argv[])
  41. {
  42. 	int c;
  43. 	bool flag_i = false;
  44. 	char *val;
  46. 	/* flawfinder: ignore. Old implementations of getopt should fix themselves */
  47. 	while((c = getopt(argc, argv, ":iu:-:")) != -1)
  48. 	{
  49. 		switch(c)
  50. 		{
  51. 		case 'i':
  52. 			flag_i = true;
  53. 			break;
  54. 		case 'u':
  55. 			unsetenv(optarg);
  56. 			break;
  57. 		case '-':
  58. 			val = strchr(optarg, '=');
  59. 			if(val == NULL)
  60. 			{
  61. 				fprintf(stderr, "env: Error: Missing = in long option\n");
  62. 				return 1;
  63. 			}
  65. 			*val = 0;
  66. 			val++;
  68. 			if(strcmp(optarg, "unset") != 0)
  69. 			{
  70. 				fprintf(stderr, "env: Error: Unknown long option --%s\n", optarg);
  71. 				return 1;
  72. 			}
  73. 			unsetenv(val);
  75. 			break;
  76. 		case ':':
  77. 			fprintf(stderr, "env: Error: Missing operand for option: '-%c'\n", optopt);
  78. 			usage();
  79. 			return 1;
  80. 		case '?':
  81. 			fprintf(stderr, "env: Error: Unrecognised option: '-%c'\n", optopt);
  82. 			usage();
  83. 			return 1;
  84. 		default:
  85. 			assert(false);
  86. 		}
  87. 	}
  89. 	argc -= optind;
  90. 	argv += optind;
  92. 	if(flag_i)
  93. 	{
  94. 		environ     = envclear;
  95. 		envclear[0] = NULL;
  96. 	}
  98. 	for(; argv[0]; argv++, argc--)
  99. 	{
  100. 		char *sep = strchr(argv[0], '=');
  101. 		if(sep == NULL)
  102. 		{
  103. 			break;
  104. 		}
  106. 		*sep = 0;
  107. 		sep++;
  109. 		if(setenv(argv[0], sep, 1))
  110. 		{
  111. 			fprintf(stderr, "env: setenv(%s, %s, 1): %s\n", argv[0], sep, strerror(errno));
  112. 			return 1;
  113. 		}
  114. 	}
  116. 	if(argc < 1)
  117. 	{
  118. 		return export();
  119. 	}
  121. 	assert(argv[0]);
  122. 	errno = 0;
  123. 	/* flawfinder: ignore. No restrictions on commands is intended */
  124. 	if(execvp(argv[0], argv) < 0)
  125. 	{
  126. 		fprintf(stderr, "env: execvp(\"%s\", ...): %s\n", argv[0], strerror(errno));
  128. 		return (errno == ENOENT) ? 127 : 126;
  129. 	}
  131. 	assert(false);
  132. }