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utils-std

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

tee.c (2901B)

    

  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 <assert.h> /* assert() */
  10. #include <errno.h>  /* errno */
  11. #include <signal.h> /* signal() */
  12. #include <stdio.h>  /* fprintf(), fgetc(), fputc(), fclose(), fopen() */
  13. #include <stdlib.h> /* calloc(), free(), abort() */
  14. #include <string.h> /* strerror() */
  15. #include <unistd.h> /* getopt(), opt… */
  16. #ifdef HAS_GETOPT_LONG
  17. #include <getopt.h>
  18. #endif
  20. const char *argv0 = "tee";
  22. static void
  23. cleanup(FILE **fds)
  24. {
  25. 	if(fds != NULL)
  26. 	{
  27. 		free(fds);
  28. 	}
  29. }
  31. int
  32. main(int argc, char *argv[])
  33. {
  34. 	const char *mode = "w";
  35. 	FILE **fds = {NULL}; // Shut up GCC
  36. 	int c;
  38. #ifdef HAS_GETOPT_LONG
  39. 	// Strictly for GNUisms compatibility so no long-only options
  40. 	// clang-format off
  41. 	static struct option opts[] = {
  42. 		{"append", required_argument, NULL, 'a'},
  43. 		{"ignore-interrupts", required_argument, NULL, 'i'},
  44. 		{0, 0, 0, 0},
  45. 	};
  46. 	// clang-format on
  48. 	// Need + as first character to get POSIX-style option parsing
  49. 	for(int c = -1; (c = getopt_long(argc, argv, "+:ai", opts, NULL)) != -1;)
  50. #else
  51. 	for(int c = -1; (c = getopt_nolong(argc, argv, ":ai")) != -1;)
  52. #endif
  53. 	{
  54. 		switch(c)
  55. 		{
  56. 		case 'a':
  57. 			mode = "a";
  58. 			break;
  59. 		case 'i': /* ignore SIGINT */;
  60. 			signal(SIGINT, SIG_IGN);
  61. 			break;
  62. 		case ':':
  63. 			fprintf(stderr, "tee: error: Missing operand for option: '-%c'\n", optopt);
  64. 			return 1;
  65. 		case '?':
  66. 			GETOPT_UNKNOWN_OPT
  67. 			return 1;
  68. 		default:
  69. 			abort();
  70. 		}
  71. 	}
  73. 	argc -= optind;
  74. 	argv += optind;
  76. 	if(argc > 0)
  77. 	{
  78. 		fds = calloc(argc, sizeof(*fds));
  79. 		if(!fds)
  80. 		{
  81. 			fprintf(stderr, "tee: error: Failed to allocate fd array: %s\n", strerror(errno));
  82. 			return 1;
  83. 		}
  84. 	}
  86. 	for(int argi = 0; argi < argc; argi++)
  87. 	{
  88. 		assert(argv[argi]);
  90. 		// POSIX: implementations shouldn't treat '-' as stdin
  91. 		fds[argi] = fopen(argv[argi], mode);
  93. 		if(fds[argi] == NULL)
  94. 		{
  95. 			fprintf(stderr, "tee: error: Failed opening file ‘%s’: %s\n", argv[argi], strerror(errno));
  96. 			cleanup(fds);
  97. 			return 1;
  98. 		}
  99. 	}
  101. 	// main loop, note that failed writes shouldn't make tee exit
  102. 	int err = 0;
  104. 	while((c = fgetc(stdin)) != EOF)
  105. 	{
  106. 		if(fputc(c, stdout) == EOF)
  107. 		{
  108. 			fprintf(stderr, "tee: error: Failed writing to stdout: %s\n", strerror(errno));
  109. 			err = 1;
  110. 			errno = 0;
  111. 		}
  113. 		for(int argi = 0; argi < argc; argi++)
  114. 		{
  115. 			if(fputc(c, fds[argi]) == EOF)
  116. 			{
  117. 				fprintf(stderr, "tee: error: Failed writing to argument %d: %s\n", argi, strerror(errno));
  118. 				err = 1;
  119. 				errno = 0;
  120. 			}
  121. 		}
  122. 	}
  124. 	// cleanup
  125. 	for(int argi = 0; argi < argc; argi++)
  126. 	{
  127. 		if(fclose(fds[argi]) != 0)
  128. 		{
  129. 			fprintf(stderr, "tee: error: Failed closing file '%s': %s\n", argv[argi], strerror(errno));
  130. 			err++;
  131. 		}
  132. 	}
  134. 	cleanup(fds);
  136. 	return err;
  137. }