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utils-std

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

pwd.c (2634B)

    

  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. #include "../config.h"
  7. #include "../libutils/getopt_nolong.h"
  9. #include <limits.h> // PATH_MAX
  10. #include <stdbool.h>
  11. #include <stdio.h>  // puts, perror, printf
  12. #include <stdlib.h> // getenv
  13. #include <sys/stat.h>
  14. #include <unistd.h> // getcwd
  15. #ifdef HAS_GETOPT_LONG
  16. #include <getopt.h>
  17. #endif
  19. const char *argv0 = "pwd";
  21. enum pwd
  22. {
  23. 	PWD_L = 0,
  24. 	PWD_P = 1,
  25. };
  27. static void
  28. usage(void)
  29. {
  30. 	fputs("Usage: pwd [-L|-P]\n", stderr);
  31. }
  33. static bool
  34. is_absolute(char *path)
  35. {
  36. 	if(!path) return false;
  37. 	if(path[0] != '/') return false;
  39. 	size_t dotlen = 0;
  40. 	for(size_t i = 1; path[i] != '\0'; i++)
  41. 	{
  42. 		switch(path[i])
  43. 		{
  44. 		case '.':
  45. 			dotlen++;
  46. 			break;
  47. 		case '/':
  48. 			if(dotlen == 1 || dotlen == 2) return false;
  50. 			dotlen = 0;
  51. 			break;
  52. 		default:
  53. 			dotlen = 0;
  54. 			break;
  55. 		}
  56. 	}
  58. 	return true;
  59. }
  61. static bool
  62. is_pwd(char *path)
  63. {
  64. 	if(!is_absolute(path)) return false;
  66. 	struct stat path_status;
  67. 	if(stat(path, &path_status) < 0) return false;
  69. 	struct stat dot_status;
  70. 	if(stat(".", &dot_status) < 0) return false;
  72. 	if(path_status.st_dev != dot_status.st_dev) return false;
  73. 	if(path_status.st_ino != dot_status.st_ino) return false;
  75. 	return true;
  76. }
  78. int
  79. main(int argc, char *argv[])
  80. {
  81. 	enum pwd mode = PWD_L;
  83. #ifdef HAS_GETOPT_LONG
  84. 	// Strictly for GNUisms compatibility so no long-only options
  85. 	// clang-format off
  86. 	static struct option opts[] = {
  87. 		{"logical", no_argument, NULL, 'L'},
  88. 		{"physical", no_argument, NULL, 'P'},
  89. 		{0, 0, 0, 0},
  90. 	};
  91. 	// clang-format on
  93. 	// Need + as first character to get POSIX-style option parsing
  94. 	for(int c = -1; (c = getopt_long(argc, argv, "+:LP", opts, NULL)) != -1;)
  95. #else
  96. 	for(int c = -1; (c = getopt_nolong(argc, argv, ":LP")) != -1;)
  97. #endif
  98. 	{
  99. 		switch(c)
  100. 		{
  101. 		case 'L':
  102. 			mode = PWD_L;
  103. 			break;
  104. 		case 'P':
  105. 			mode = PWD_P;
  106. 			break;
  107. 		case ':':
  108. 			fprintf(stderr, "%s: error: Missing operand for option '-%c'\n", argv0, optopt);
  109. 			usage();
  110. 			return 1;
  111. 		case '?':
  112. 			GETOPT_UNKNOWN_OPT
  113. 			usage();
  114. 			return 1;
  115. 		}
  116. 	}
  118. 	argc -= optind;
  119. 	argv += optind;
  121. 	if(argc != 0)
  122. 	{
  123. 		usage();
  124. 		return 1;
  125. 	}
  127. 	if(mode == PWD_L)
  128. 	{
  129. 		char *pwd = getenv("PWD");
  130. 		if(is_pwd(pwd))
  131. 		{
  132. 			if(puts(pwd) < 0)
  133. 			{
  134. 				perror("pwd: error: puts");
  135. 				return 1;
  136. 			}
  138. 			return 0;
  139. 		}
  140. 	}
  142. 	char pwd[PATH_MAX] = "";
  143. 	if(getcwd(pwd, sizeof(pwd)) == NULL)
  144. 	{
  145. 		perror("pwd: error: getcwd");
  146. 		return 1;
  147. 	}
  149. 	if(puts(pwd) < 0)
  150. 	{
  151. 		perror("pwd: error: puts");
  152. 		return 1;
  153. 	}
  155. 	return 0;
  156. }