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utils-std

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

cat.c (2719B)

    

  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/fs.h"
  8. #include "../libutils/getopt_nolong.h"
  10. #include <errno.h>
  11. #include <fcntl.h>  // open, O_RDONLY
  12. #include <limits.h> // SSIZE_MAX
  13. #include <stdio.h>  // fprintf, BUFSIZ
  14. #include <stdlib.h> // abort
  15. #include <string.h> // strerror, strncmp
  16. #include <unistd.h> // read, write, close, getopt
  18. const char *argv0 = "cat";
  20. static void
  21. usage(void)
  22. {
  23. 	fprintf(stderr, "Usage: cat [-u] [files ...]\n");
  24. }
  26. int
  27. main(int argc, char *argv[])
  28. {
  29. 	for(int c = -1; (c = getopt_nolong(argc, argv, ":u")) != -1;)
  30. 	{
  31. 		switch(c)
  32. 		{
  33. 		case 'u':
  34. 			// POSIX: Ignored, buffered streams aren't used
  35. 			break;
  36. 		case ':':
  37. 			fprintf(stderr, "%s: error: Missing operand for option: '-%c'\n", argv0, optopt);
  38. 			usage();
  39. 			return 1;
  40. 		case '?':
  41. 			GETOPT_UNKNOWN_OPT
  42. 			usage();
  43. 			return 1;
  44. 		default:
  45. 			abort();
  46. 		}
  47. 	}
  49. 	argc -= optind;
  50. 	argv += optind;
  52. 	if(argc < 1)
  53. 	{
  54. 		if(auto_fd_copy(STDIN_FILENO, STDOUT_FILENO, SSIZE_MAX) < 0)
  55. 		{
  56. 			fprintf(stderr, "%s: error: Failed copying data from <stdin>: %s\n", argv0, strerror(errno));
  57. 			return 1;
  58. 		}
  59. 	}
  60. 	else
  61. 	{
  62. 		for(int argi = 0; argi < argc; argi++)
  63. 		{
  64. 			if(strncmp(argv[argi], "-", 2) == 0)
  65. 			{
  66. 				if(auto_fd_copy(STDIN_FILENO, STDOUT_FILENO, SSIZE_MAX) < 0)
  67. 				{
  68. 					fprintf(
  69. 					    stderr, "%s: error: Failed copying data from <stdin>: %s\n", argv0, strerror(errno));
  70. 					return 1;
  71. 				}
  72. 			}
  73. 			else
  74. 			{
  75. 				int fd = open(argv[argi], O_RDONLY);
  76. 				if(fd < 0)
  77. 				{
  78. 					fprintf(stderr,
  79. 					        "%s: error: Failed opening file '%s': %s\n",
  80. 					        argv0,
  81. 					        argv[argi],
  82. 					        strerror(errno));
  83. 					errno = 0;
  84. 					return 1;
  85. 				}
  87. 				posix_fadvise(fd, 0, 0, POSIX_FADV_SEQUENTIAL);
  88. 				errno = 0;
  90. 				if(auto_fd_copy(fd, STDOUT_FILENO, SSIZE_MAX) < 0)
  91. 				{
  92. 					fprintf(stderr,
  93. 					        "%s: error: Failed copying data from file '%s': %s\n",
  94. 					        argv0,
  95. 					        argv[argi],
  96. 					        strerror(errno));
  97. 					return 1;
  98. 				}
  100. 				if(close(fd) < 0)
  101. 				{
  102. 					fprintf(stderr,
  103. 					        "%s: error: Failed closing file '%s': %s\n",
  104. 					        argv0,
  105. 					        argv[argi],
  106. 					        strerror(errno));
  107. 					errno = 0;
  108. 					return 1;
  109. 				}
  110. 			}
  111. 		}
  112. 	}
  114. 	if(close(STDIN_FILENO) != 0)
  115. 	{
  116. 		fprintf(stderr, "%s: error: Failed closing file <stdin>: %s\n", argv0, strerror(errno));
  117. 		return 1;
  118. 	}
  120. 	if(close(STDOUT_FILENO) != 0)
  121. 	{
  122. 		fprintf(stderr, "%s: error: Failed closing file <stdout>: %s\n", argv0, strerror(errno));
  123. 		return 1;
  124. 	}
  126. 	return 0;
  127. }