1/* See LICENSE file for copyright and license details. */
  2
  3
  4#include <sys/resource.h>
  5
  6#include <errno.h>
  7#include <pwd.h>
  8#include <stdlib.h>
  9
 10#include "util.h"
 11
 12#ifndef PRIO_MIN
 13#define PRIO_MIN -NZERO
 14#endif
 15
 16#ifndef PRIO_MAX
 17#define PRIO_MAX (NZERO-1)
 18#endif
 19
 20static int
 21renice(int which, int who, long adj)
 22{
 23	errno = 0;
 24	adj += getpriority(which, who);
 25	if (errno) {
 26		weprintf("getpriority %d:", who);
 27		return 0;
 28	}
 29
 30	adj = MAX(PRIO_MIN, MIN(adj, PRIO_MAX));
 31	if (setpriority(which, who, (int)adj) < 0) {
 32		weprintf("setpriority %d:", who);
 33		return 0;
 34	}
 35
 36	return 1;
 37}
 38
 39static void
 40usage(void)
 41{
 42	eprintf("usage: %s -n num [-g | -p | -u] id ...\n", argv0);
 43}
 44
 45// ?man renice: alter priority of processes
 46// ?man arguments: -n num id ...
 47// ?man change the scheduling priority of running processes
 48int
 49main(int argc, char *argv[])
 50{
 51	const char *adj = NULL;
 52	long val;
 53	int which = PRIO_PROCESS, ret = 0;
 54	struct passwd *pw;
 55	int who;
 56
 57	ARGBEGIN {
 58	// ?man -n:str: print line numbers or counts
 59	case 'n':
 60		adj = EARGF(usage());
 61		break;
 62	// ?man -g: specify option flag
 63	case 'g':
 64		which = PRIO_PGRP;
 65		break;
 66	// ?man -p: preserve file attributes
 67	case 'p':
 68		which = PRIO_PROCESS;
 69		break;
 70	// ?man -u: unbuffered output
 71	case 'u':
 72		which = PRIO_USER;
 73		break;
 74	default:
 75		usage();
 76	} ARGEND
 77
 78	if (!argc || !adj)
 79		usage();
 80
 81	val = estrtonum(adj, PRIO_MIN, PRIO_MAX);
 82	for (; *argv; argc--, argv++) {
 83		if (which == PRIO_USER) {
 84			errno = 0;
 85			if (!(pw = getpwnam(*argv))) {
 86				if (errno)
 87					weprintf("getpwnam %s:", *argv);
 88				else
 89					weprintf("getpwnam %s: no user found\n", *argv);
 90				ret = 1;
 91				continue;
 92			}
 93			who = pw->pw_uid;
 94		} else {
 95			who = estrtonum(*argv, 1, INT_MAX);
 96		}
 97		if (!renice(which, who, val))
 98			ret = 1;
 99	}
100
101	return ret;
102}