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utils-std

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

nice.c (2370B)

    

  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. #define _XOPEN_SOURCE 700 // nice() is in XSI
  7. #include "../config.h"
  8. #include "../libutils/getopt_nolong.h"
  10. #include <assert.h>
  11. #include <errno.h>
  12. #include <stdio.h>  // fprintf
  13. #include <stdlib.h> // abort
  14. #include <string.h> // strerror
  15. #include <unistd.h> // getopt, nice
  16. #ifdef HAS_GETOPT_LONG
  17. #include <getopt.h>
  18. #endif
  20. const char *argv0 = "nice";
  22. static void
  23. usage(void)
  24. {
  25. 	fprintf(stderr, "Usage: nice [-n increment] command [argument ...]\n");
  26. }
  28. int
  29. main(int argc, char *argv[])
  30. {
  31. 	long incr = 0;
  33. #ifdef HAS_GETOPT_LONG
  34. 	// Strictly for GNUisms compatibility so no long-only options
  35. 	// clang-format off
  36. 	static struct option opts[] = {
  37. 		{"adjustment", required_argument, NULL, 'n'},
  38. 		{0, 0, 0, 0},
  39. 	};
  40. 	// clang-format on
  42. 	// Need + as first character to get POSIX-style option parsing
  43. 	for(int c = -1; (c = getopt_long(argc, argv, "+:n:", opts, NULL)) != -1;)
  44. #else
  45. 	for(int c = -1; (c = getopt_nolong(argc, argv, ":n:")) != -1;)
  46. #endif
  47. 	{
  48. 		char *endptr = NULL;
  50. 		switch(c)
  51. 		{
  52. 		case 'n':
  53. 			incr = strtol(optarg, &endptr, 10);
  55. 			if(endptr && *endptr != 0) errno = EINVAL;
  56. 			if(errno != 0)
  57. 			{
  58. 				fprintf(stderr,
  59. 				        "%s: error: Failed parsing '%s' as a number: %s\n",
  60. 				        argv0,
  61. 				        optarg,
  62. 				        strerror(errno));
  63. 				usage();
  64. 				return 125;
  65. 			}
  66. 			break;
  67. 		case ':':
  68. 			fprintf(stderr, "%s: error: Missing operand for option: '-%c'\n", argv0, optopt);
  69. 			usage();
  70. 			return 125;
  71. 		case '?':
  72. 			GETOPT_UNKNOWN_OPT
  73. 			usage();
  74. 			return 125;
  75. 		default:
  76. 			abort();
  77. 		}
  78. 	}
  80. 	argc -= optind;
  81. 	argv += optind;
  83. 	if(argc == 0) return 0;
  85. 	errno = 0;
  87. 	if(nice((int)incr) == -1)
  88. 	{
  89. 		switch(errno)
  90. 		{
  91. 		case 0:
  92. 			break;
  93. 		case EPERM:
  94. 			fprintf(
  95. 			    stderr, "%s: warning: Failed setting nice to %ld: %s\n", argv0, incr, strerror(errno));
  96. 			errno = 0;
  97. 			break;
  98. 		default:
  99. 			fprintf(stderr, "%s: error: Failed setting nice to %ld: %s\n", argv0, incr, strerror(errno));
  100. 			return 125;
  101. 		}
  102. 	}
  104. 	assert(argv[0]);
  105. 	if(execvp(argv[0], argv) < 0)
  106. 	{
  107. 		fprintf(stderr, "%s: error: Failed executing '%s': %s\n", argv0, argv[0], strerror(errno));
  109. 		return (errno == ENOENT) ? 127 : 126;
  110. 	}
  112. 	abort();
  113. }