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utils-std

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

cat.c (2696B)

    

  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 "../libutils/fs.h"
  7. #include "../libutils/getopt_nolong.h"
  9. #include <errno.h>
  10. #include <fcntl.h>  // open, O_RDONLY
  11. #include <limits.h> // SSIZE_MAX
  12. #include <stdio.h>  // fprintf, BUFSIZ
  13. #include <stdlib.h> // abort
  14. #include <string.h> // strerror, strncmp
  15. #include <unistd.h> // read, write, close, getopt
  17. const char *argv0 = "cat";
  19. static void
  20. usage(void)
  21. {
  22. 	fprintf(stderr, "Usage: cat [-u] [files ...]\n");
  23. }
  25. int
  26. main(int argc, char *argv[])
  27. {
  28. 	for(int c = -1; (c = getopt_nolong(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. 			GETOPT_UNKNOWN_OPT
  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. 				posix_fadvise(fd, 0, 0, POSIX_FADV_SEQUENTIAL);
  87. 				errno = 0;
  89. 				if(auto_fd_copy(fd, STDOUT_FILENO, SSIZE_MAX) < 0)
  90. 				{
  91. 					fprintf(stderr,
  92. 					        "%s: error: Failed copying data from file '%s': %s\n",
  93. 					        argv0,
  94. 					        argv[argi],
  95. 					        strerror(errno));
  96. 					return 1;
  97. 				}
  99. 				if(close(fd) < 0)
  100. 				{
  101. 					fprintf(stderr,
  102. 					        "%s: error: Failed closing file '%s': %s\n",
  103. 					        argv0,
  104. 					        argv[argi],
  105. 					        strerror(errno));
  106. 					errno = 0;
  107. 					return 1;
  108. 				}
  109. 			}
  110. 		}
  111. 	}
  113. 	if(close(STDIN_FILENO) != 0)
  114. 	{
  115. 		fprintf(stderr, "%s: error: Failed closing file <stdin>: %s\n", argv0, strerror(errno));
  116. 		return 1;
  117. 	}
  119. 	if(close(STDOUT_FILENO) != 0)
  120. 	{
  121. 		fprintf(stderr, "%s: error: Failed closing file <stdout>: %s\n", argv0, strerror(errno));
  122. 		return 1;
  123. 	}
  125. 	return 0;
  126. }