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utils-std

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

renice.c (3273B)

    

  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 // getpriority, setpriority
  8. #include <assert.h>
  9. #include <errno.h>
  10. #include <stdio.h>        // fprintf
  11. #include <stdlib.h>       // abort
  12. #include <string.h>       // strerror
  13. #include <sys/resource.h> // getpriority, setpriority
  14. #include <unistd.h>       // getopt, nice
  16. static int
  17. renice(int which, id_t who, int adj)
  18. {
  19. 	const char *which_s = NULL;
  20. 	switch(which)
  21. 	{
  22. 	case PRIO_PROCESS:
  23. 		which_s = "PRIO_PROCESS";
  24. 		break;
  25. 	case PRIO_PGRP:
  26. 		which_s = "PRIO_PGRP";
  27. 		break;
  28. 	case PRIO_USER:
  29. 		which_s = "PRIO_USER";
  30. 		break;
  31. 	default:
  32. 		which_s = NULL;
  33. 	}
  35. 	errno = 0;
  36. 	int prio = getpriority(which, who);
  37. 	if(errno != 0)
  38. 	{
  39. 		fprintf(stderr, "renice: getpriority(%s, %d): %s\n", which_s, who, strerror(errno));
  40. 		return -1;
  41. 	}
  43. 	prio += adj;
  45. 	if(setpriority(which, who, prio) != 0)
  46. 	{
  47. 		fprintf(stderr, "renice: setpriority(%s, %d, %d): %s\n", which_s, who, prio, strerror(errno));
  48. 		return -1;
  49. 	}
  51. 	return 0;
  52. }
  54. static void
  55. usage(void)
  56. {
  57. 	fprintf(stderr, "\
  58. Usage: renice [-p] -n adj PID...\n\
  59.        renice  -g  -n adj PGID...\n\
  60.        renice  -u  -n adj UID...\n\
  61. ");
  62. }
  64. int
  65. main(int argc, char *argv[])
  66. {
  67. 	long adj = 0;
  68. 	int which = PRIO_PROCESS;
  70. 	int c = -1;
  71. 	while((c = getopt(argc, argv, ":gpun:")) != -1)
  72. 	{
  73. 		switch(c)
  74. 		{
  75. 		case 'g':
  76. 			which = PRIO_PGRP;
  77. 			break;
  78. 		case 'p':
  79. 			which = PRIO_PROCESS;
  80. 			break;
  81. 		case 'u':
  82. 			which = PRIO_USER;
  83. 			break;
  84. 		case 'n':
  85. 			assert(errno == 0);
  86. 			char *endptr = NULL;
  88. 			adj = strtol(optarg, &endptr, 10);
  90. 			if(endptr && *endptr != 0) errno = EINVAL;
  91. 			if(errno != 0)
  92. 			{
  93. 				fprintf(stderr,
  94. 				        "renice: Error: Failed parsing '%s' as a number: %s\n",
  95. 				        optarg,
  96. 				        strerror(errno));
  97. 				usage();
  98. 				return 1;
  99. 			}
  100. 			if(adj < PRIO_MIN)
  101. 			{
  102. 				fprintf(stderr, "renice: Error: '-n %ld' is lower than PRIO_MIN(%d)\n", adj, PRIO_MIN);
  103. 				return 1;
  104. 			}
  105. 			if(adj > PRIO_MAX)
  106. 			{
  107. 				fprintf(stderr, "renice: Error: '-n %ld' is greater than PRIO_MAX(%d)\n", adj, PRIO_MAX);
  108. 				return 1;
  109. 			}
  110. 			if(adj == 0)
  111. 			{
  112. 				fprintf(stderr, "renice: Error: '-n 0' makes no sense\n");
  113. 				return 1;
  114. 			}
  115. 			break;
  116. 		case ':':
  117. 			fprintf(stderr, "renice: Error: Missing operand for option: '-%c'\n", optopt);
  118. 			usage();
  119. 			return 1;
  120. 		case '?':
  121. 			fprintf(stderr, "renice: Error: Unrecognised option: '-%c'\n", optopt);
  122. 			usage();
  123. 			return 1;
  124. 		default:
  125. 			abort();
  126. 		}
  127. 	}
  129. 	argc -= optind;
  130. 	argv += optind;
  132. 	if(argc == 0)
  133. 	{
  134. 		fprintf(stderr, "renice: Error: No IDs passed\n");
  135. 		usage();
  136. 		return 1;
  137. 	}
  139. 	if(adj == 0)
  140. 	{
  141. 		fprintf(stderr, "renice: Mandatory option '-n adj' not passed\n");
  142. 		usage();
  143. 		return 1;
  144. 	}
  146. 	for(int i = 0; i < argc; i++)
  147. 	{
  148. 		char *endptr = NULL;
  149. 		char *arg = argv[i];
  151. 		long who = strtol(arg, &endptr, 0);
  152. 		if(endptr && *endptr != 0) errno = EINVAL;
  154. 		if(errno != 0)
  155. 		{
  156. 			fprintf(stderr,
  157. 			        "renice: Error: Failed parsing argument '%s' as a number: %s\n",
  158. 			        arg,
  159. 			        strerror(errno));
  160. 			usage();
  161. 			return 1;
  162. 		}
  164. 		if(renice(which, who, adj) != 0) return 1;
  165. 	}
  167. 	return 0;
  168. }