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utils-std

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

cat.c (2635B)

    

  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 "../lib/fs.h"
  8. #include <errno.h>
  9. #include <fcntl.h>  // open, O_RDONLY
  10. #include <limits.h> // SSIZE_MAX
  11. #include <stdio.h>  // fprintf, BUFSIZ
  12. #include <stdlib.h> // abort
  13. #include <string.h> // strerror, strncmp
  14. #include <unistd.h> // read, write, close, getopt
  16. const char *argv0 = "cat";
  18. static void
  19. usage(void)
  20. {
  21. 	fprintf(stderr, "Usage: cat [-u] [files ...]\n");
  22. }
  24. int
  25. main(int argc, char *argv[])
  26. {
  27. 	int c = -1;
  28. 	while((c = getopt(argc, argv, ":u")) != -1)
  29. 	{
  30. 		switch(c)
  31. 		{
  32. 		case 'u':
  33. 			// POSIX: Ignored, buffered streams aren't used
  34. 			break;
  35. 		case ':':
  36. 			fprintf(stderr, "%s: error: Missing operand for option: '-%c'\n", argv0, optopt);
  37. 			usage();
  38. 			return 1;
  39. 		case '?':
  40. 			fprintf(stderr, "%s: error: Unrecognised option: '-%c'\n", argv0, optopt);
  41. 			usage();
  42. 			return 1;
  43. 		default:
  44. 			abort();
  45. 		}
  46. 	}
  48. 	argc -= optind;
  49. 	argv += optind;
  51. 	if(argc < 1)
  52. 	{
  53. 		if(auto_fd_copy(STDIN_FILENO, STDOUT_FILENO, SSIZE_MAX) < 0)
  54. 		{
  55. 			fprintf(stderr, "%s: error: Failed copying data from <stdin>: %s\n", argv0, strerror(errno));
  56. 			return 1;
  57. 		}
  58. 	}
  59. 	else
  60. 	{
  61. 		for(int argi = 0; argi < argc; argi++)
  62. 		{
  63. 			if(strncmp(argv[argi], "-", 2) == 0)
  64. 			{
  65. 				if(auto_fd_copy(STDIN_FILENO, STDOUT_FILENO, SSIZE_MAX) < 0)
  66. 				{
  67. 					fprintf(
  68. 					    stderr, "%s: error: Failed copying data from <stdin>: %s\n", argv0, strerror(errno));
  69. 					return 1;
  70. 				}
  71. 			}
  72. 			else
  73. 			{
  74. 				int fd = open(argv[argi], O_RDONLY);
  75. 				if(fd < 0)
  76. 				{
  77. 					fprintf(stderr,
  78. 					        "%s: error: Failed opening file '%s': %s\n",
  79. 					        argv0,
  80. 					        argv[argi],
  81. 					        strerror(errno));
  82. 					errno = 0;
  83. 					return 1;
  84. 				}
  86. 				if(auto_fd_copy(fd, STDOUT_FILENO, SSIZE_MAX) < 0)
  87. 				{
  88. 					fprintf(stderr,
  89. 					        "%s: error: Failed copying data from file '%s': %s\n",
  90. 					        argv0,
  91. 					        argv[argi],
  92. 					        strerror(errno));
  93. 					return 1;
  94. 				}
  96. 				if(close(fd) < 0)
  97. 				{
  98. 					fprintf(stderr,
  99. 					        "%s: error: Failed closing file '%s': %s\n",
  100. 					        argv0,
  101. 					        argv[argi],
  102. 					        strerror(errno));
  103. 					errno = 0;
  104. 					return 1;
  105. 				}
  106. 			}
  107. 		}
  108. 	}
  110. 	if(close(STDIN_FILENO) != 0)
  111. 	{
  112. 		fprintf(stderr, "%s: error: Failed closing file <stdin>: %s\n", argv0, strerror(errno));
  113. 		return 1;
  114. 	}
  116. 	if(close(STDOUT_FILENO) != 0)
  117. 	{
  118. 		fprintf(stderr, "%s: error: Failed closing file <stdout>: %s\n", argv0, strerror(errno));
  119. 		return 1;
  120. 	}
  122. 	return 0;
  123. }