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utils-std

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

renice.c (3344B)

    

  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: error: 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,
  48. 		        "renice: error: setpriority(%s, %d, %d): %s\n",
  49. 		        which_s,
  50. 		        who,
  51. 		        prio,
  52. 		        strerror(errno));
  53. 		return -1;
  54. 	}
  56. 	return 0;
  57. }
  59. static void
  60. usage(void)
  61. {
  62. 	fprintf(stderr, "\
  63. Usage: renice [-p] -n adj PID...\n\
  64.        renice  -g  -n adj PGID...\n\
  65.        renice  -u  -n adj UID...\n\
  66. ");
  67. }
  69. int
  70. main(int argc, char *argv[])
  71. {
  72. 	long adj = 0;
  73. 	int which = PRIO_PROCESS;
  75. 	int c = -1;
  76. 	while((c = getopt(argc, argv, ":gpun:")) != -1)
  77. 	{
  78. 		switch(c)
  79. 		{
  80. 		case 'g':
  81. 			which = PRIO_PGRP;
  82. 			break;
  83. 		case 'p':
  84. 			which = PRIO_PROCESS;
  85. 			break;
  86. 		case 'u':
  87. 			which = PRIO_USER;
  88. 			break;
  89. 		case 'n':
  90. 			assert(errno == 0);
  91. 			char *endptr = NULL;
  93. 			adj = strtol(optarg, &endptr, 10);
  95. 			if(endptr && *endptr != 0) errno = EINVAL;
  96. 			if(errno != 0)
  97. 			{
  98. 				fprintf(stderr,
  99. 				        "renice: error: Failed parsing '%s' as a number: %s\n",
  100. 				        optarg,
  101. 				        strerror(errno));
  102. 				usage();
  103. 				return 1;
  104. 			}
  105. 			if(adj < PRIO_MIN)
  106. 			{
  107. 				fprintf(stderr, "renice: error: '-n %ld' is lower than PRIO_MIN(%d)\n", adj, PRIO_MIN);
  108. 				return 1;
  109. 			}
  110. 			if(adj > PRIO_MAX)
  111. 			{
  112. 				fprintf(stderr, "renice: error: '-n %ld' is greater than PRIO_MAX(%d)\n", adj, PRIO_MAX);
  113. 				return 1;
  114. 			}
  115. 			if(adj == 0)
  116. 			{
  117. 				fprintf(stderr, "renice: error: '-n 0' makes no sense\n");
  118. 				return 1;
  119. 			}
  120. 			break;
  121. 		case ':':
  122. 			fprintf(stderr, "renice: error: Missing operand for option: '-%c'\n", optopt);
  123. 			usage();
  124. 			return 1;
  125. 		case '?':
  126. 			fprintf(stderr, "renice: error: Unrecognised option: '-%c'\n", optopt);
  127. 			usage();
  128. 			return 1;
  129. 		default:
  130. 			abort();
  131. 		}
  132. 	}
  134. 	argc -= optind;
  135. 	argv += optind;
  137. 	if(argc == 0)
  138. 	{
  139. 		fprintf(stderr, "renice: error: No IDs passed\n");
  140. 		usage();
  141. 		return 1;
  142. 	}
  144. 	if(adj == 0)
  145. 	{
  146. 		fprintf(stderr, "renice: error: Mandatory option '-n adj' not passed\n");
  147. 		usage();
  148. 		return 1;
  149. 	}
  151. 	for(int i = 0; i < argc; i++)
  152. 	{
  153. 		char *endptr = NULL;
  154. 		char *arg = argv[i];
  156. 		long who = strtol(arg, &endptr, 0);
  157. 		if(endptr && *endptr != 0) errno = EINVAL;
  159. 		if(errno != 0)
  160. 		{
  161. 			fprintf(stderr,
  162. 			        "renice: error: Failed parsing argument '%s' as a number: %s\n",
  163. 			        arg,
  164. 			        strerror(errno));
  165. 			usage();
  166. 			return 1;
  167. 		}
  169. 		if(renice(which, who, adj) != 0) return 1;
  170. 	}
  172. 	return 0;
  173. }