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utils-std

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

tee.c (3155B)

    

  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 <fcntl.h>
  12. #include <signal.h> /* signal() */
  13. #include <stdio.h>  /* fprintf() */
  14. #include <stdlib.h> /* calloc(), free(), abort() */
  15. #include <string.h> /* strerror() */
  16. #include <unistd.h> /* getopt(), opt… */
  17. #ifdef HAS_GETOPT_LONG
  18. #include <getopt.h>
  19. #endif
  21. const char *argv0 = "tee";
  23. static void
  24. cleanup(int *fds)
  25. {
  26. 	free(fds);
  27. }
  29. int
  30. main(int argc, char *argv[])
  31. {
  32. 	mode_t mode = O_WRONLY | O_NOCTTY | O_CREAT;
  33. 	int *fds = NULL;
  34. 	int c;
  36. #ifdef HAS_GETOPT_LONG
  37. 	// Strictly for GNUisms compatibility so no long-only options
  38. 	// clang-format off
  39. 	static struct option opts[] = {
  40. 		{"append", required_argument, NULL, 'a'},
  41. 		{"ignore-interrupts", required_argument, NULL, 'i'},
  42. 		{0, 0, 0, 0},
  43. 	};
  44. 	// clang-format on
  46. 	// Need + as first character to get POSIX-style option parsing
  47. 	for(int c = -1; (c = getopt_long(argc, argv, "+:ai", opts, NULL)) != -1;)
  48. #else
  49. 	for(int c = -1; (c = getopt_nolong(argc, argv, ":ai")) != -1;)
  50. #endif
  51. 	{
  52. 		switch(c)
  53. 		{
  54. 		case 'a':
  55. 			mode |= O_APPEND;
  56. 			break;
  57. 		case 'i': /* ignore SIGINT */;
  58. 			signal(SIGINT, SIG_IGN);
  59. 			break;
  60. 		case ':':
  61. 			fprintf(stderr, "tee: error: Missing operand for option: '-%c'\n", optopt);
  62. 			return 1;
  63. 		case '?':
  64. 			GETOPT_UNKNOWN_OPT
  65. 			return 1;
  66. 		default:
  67. 			abort();
  68. 		}
  69. 	}
  71. 	argc -= optind;
  72. 	argv += optind;
  74. 	if(argc > 0)
  75. 	{
  76. 		fds = calloc(argc, sizeof(*fds));
  77. 		if(!fds)
  78. 		{
  79. 			fprintf(stderr, "tee: error: Failed to allocate fd array: %s\n", strerror(errno));
  80. 			return 1;
  81. 		}
  82. 	}
  84. 	for(int argi = 0; argi < argc; argi++)
  85. 	{
  86. 		assert(argv[argi]);
  88. 		// POSIX: implementations shouldn't treat '-' as stdin
  89. 		fds[argi] = open(argv[argi], mode, 0666);
  91. 		if(fds[argi] < 0)
  92. 		{
  93. 			fprintf(stderr, "tee: error: Failed opening file ‘%s’: %s\n", argv[argi], strerror(errno));
  94. 			cleanup(fds);
  95. 			return 1;
  96. 		}
  97. 	}
  99. 	// main loop, note that failed writes shouldn't make tee exit
  100. 	int err = 0;
  102. 	while(true)
  103. 	{
  104. 		static char buf[BUFSIZ];
  105. 		ssize_t sread = read(STDIN_FILENO, buf, sizeof(buf));
  106. 		if(sread == 0) break;
  107. 		if(sread < 0)
  108. 		{
  109. 			fprintf(stderr, "tee: error: Failed reading from stdin: %s\n", strerror(errno));
  110. 			cleanup(fds);
  111. 			return 1;
  112. 		}
  114. 		size_t nread = (size_t)sread;
  116. 		if(write(STDOUT_FILENO, buf, nread) < 0)
  117. 		{
  118. 			fprintf(stderr, "tee: error: Failed writing to stdout: %s\n", strerror(errno));
  119. 			err = 1;
  120. 			errno = 0;
  121. 		}
  123. 		for(int argi = 0; argi < argc; argi++)
  124. 		{
  125. 			if(write(fds[argi], buf, nread) < 0)
  126. 			{
  127. 				fprintf(
  128. 				    stderr, "tee: error: Failed writing to file '%s': %s\n", argv[argi], strerror(errno));
  129. 				err = 1;
  130. 				errno = 0;
  131. 			}
  132. 		}
  133. 	}
  135. 	// cleanup
  136. 	for(int argi = 0; argi < argc; argi++)
  137. 	{
  138. 		if(close(fds[argi]) != 0)
  139. 		{
  140. 			fprintf(stderr, "tee: error: Failed closing file '%s': %s\n", argv[argi], strerror(errno));
  141. 			err++;
  142. 		}
  143. 	}
  145. 	cleanup(fds);
  147. 	return err;
  148. }