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utils-std

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

renice.c (3298B)

    

  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 <errno.h>
  9. #include <stdio.h>        // fprintf
  10. #include <stdlib.h>       // abort
  11. #include <string.h>       // strerror
  12. #include <sys/resource.h> // getpriority, setpriority
  13. #include <unistd.h>       // getopt, nice
  15. static int
  16. renice(int which, id_t who, int adj)
  17. {
  18. 	const char *which_s = NULL;
  19. 	switch(which)
  20. 	{
  21. 	case PRIO_PROCESS:
  22. 		which_s = "PRIO_PROCESS";
  23. 		break;
  24. 	case PRIO_PGRP:
  25. 		which_s = "PRIO_PGRP";
  26. 		break;
  27. 	case PRIO_USER:
  28. 		which_s = "PRIO_USER";
  29. 		break;
  30. 	default:
  31. 		which_s = NULL;
  32. 	}
  34. 	errno = 0;
  35. 	int prio = getpriority(which, who);
  36. 	if(errno != 0)
  37. 	{
  38. 		fprintf(stderr, "renice: error: getpriority(%s, %d): %s\n", which_s, who, strerror(errno));
  39. 		return -1;
  40. 	}
  42. 	prio += adj;
  44. 	if(setpriority(which, who, prio) != 0)
  45. 	{
  46. 		fprintf(stderr,
  47. 		        "renice: error: setpriority(%s, %d, %d): %s\n",
  48. 		        which_s,
  49. 		        who,
  50. 		        prio,
  51. 		        strerror(errno));
  52. 		return -1;
  53. 	}
  55. 	return 0;
  56. }
  58. static void
  59. usage(void)
  60. {
  61. 	fprintf(stderr, "\
  62. Usage: renice [-p] -n adj PID...\n\
  63.        renice  -g  -n adj PGID...\n\
  64.        renice  -u  -n adj UID...\n\
  65. ");
  66. }
  68. int
  69. main(int argc, char *argv[])
  70. {
  71. 	long adj = 0;
  72. 	int which = PRIO_PROCESS;
  74. 	for(int c = -1; (c = getopt(argc, argv, ":gpun:")) != -1;)
  75. 	{
  76. 		char *endptr = NULL;
  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. 			adj = strtol(optarg, &endptr, 10);
  92. 			if(endptr && *endptr != 0) errno = EINVAL;
  93. 			if(errno != 0)
  94. 			{
  95. 				fprintf(stderr,
  96. 				        "renice: error: Failed parsing '%s' as a number: %s\n",
  97. 				        optarg,
  98. 				        strerror(errno));
  99. 				usage();
  100. 				return 1;
  101. 			}
  102. 			if(adj < PRIO_MIN)
  103. 			{
  104. 				fprintf(stderr, "renice: error: '-n %ld' is lower than PRIO_MIN(%d)\n", adj, PRIO_MIN);
  105. 				return 1;
  106. 			}
  107. 			if(adj > PRIO_MAX)
  108. 			{
  109. 				fprintf(stderr, "renice: error: '-n %ld' is greater than PRIO_MAX(%d)\n", adj, PRIO_MAX);
  110. 				return 1;
  111. 			}
  112. 			if(adj == 0)
  113. 			{
  114. 				fprintf(stderr, "renice: error: '-n 0' makes no sense\n");
  115. 				return 1;
  116. 			}
  117. 			break;
  118. 		case ':':
  119. 			fprintf(stderr, "renice: error: Missing operand for option: '-%c'\n", optopt);
  120. 			usage();
  121. 			return 1;
  122. 		case '?':
  123. 			fprintf(stderr, "renice: error: Unrecognised option: '-%c'\n", optopt);
  124. 			usage();
  125. 			return 1;
  126. 		default:
  127. 			abort();
  128. 		}
  129. 	}
  131. 	argc -= optind;
  132. 	argv += optind;
  134. 	if(argc == 0)
  135. 	{
  136. 		fprintf(stderr, "renice: error: No IDs passed\n");
  137. 		usage();
  138. 		return 1;
  139. 	}
  141. 	if(adj == 0)
  142. 	{
  143. 		fprintf(stderr, "renice: error: Mandatory option '-n adj' not passed\n");
  144. 		usage();
  145. 		return 1;
  146. 	}
  148. 	for(int i = 0; i < argc; i++)
  149. 	{
  150. 		char *endptr = NULL;
  151. 		char *arg = argv[i];
  153. 		long who = strtol(arg, &endptr, 0);
  154. 		if(endptr && *endptr != 0) errno = EINVAL;
  156. 		if(errno != 0)
  157. 		{
  158. 			fprintf(stderr,
  159. 			        "renice: error: Failed parsing argument '%s' as a number: %s\n",
  160. 			        arg,
  161. 			        strerror(errno));
  162. 			usage();
  163. 			return 1;
  164. 		}
  166. 		if(renice(which, who, adj) != 0) return 1;
  167. 	}
  169. 	return 0;
  170. }