1 /*- 2 * Copyright (c) 1989 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #if defined(LIBC_SCCS) && !defined(lint) 35 /*static char sccsid[] = "from: @(#)getloadavg.c 6.2 (Berkeley) 6/29/90";*/ 36 static char rcsid[] = "$Id: getloadavg.c,v 1.2 1993/08/01 18:31:55 mycroft Exp $"; 37 #endif /* LIBC_SCCS and not lint */ 38 39 #include <sys/param.h> 40 #include <sys/types.h> 41 #include <sys/file.h> 42 #include <nlist.h> 43 44 static struct nlist nl[] = { 45 { "_averunnable" }, 46 #define X_AVERUNNABLE 0 47 { "_fscale" }, 48 #define X_FSCALE 1 49 { "" }, 50 }; 51 52 /* 53 * getloadavg() -- Get system load averages. 54 * 55 * Put `nelem' samples into `loadavg' array. 56 * Return number of samples retrieved, or -1 on error. 57 */ 58 getloadavg(loadavg, nelem) 59 double loadavg[]; 60 int nelem; 61 { 62 static int need_nlist = 1; 63 fixpt_t averunnable[3]; 64 int fscale, kmemfd, i; 65 int alreadyopen; 66 67 if ((alreadyopen = kvm_openfiles(NULL, NULL, NULL)) == -1) 68 return (-1); 69 /* 70 * cache nlist 71 */ 72 if (need_nlist) { 73 if (kvm_nlist(nl) != 0) 74 goto bad; 75 need_nlist = 0; 76 } 77 if (kvm_read((off_t)nl[X_AVERUNNABLE].n_value, (char *)averunnable, 78 sizeof(averunnable)) != sizeof(averunnable)) 79 goto bad; 80 if (kvm_read( (off_t)nl[X_FSCALE].n_value, (char *)&fscale, 81 sizeof(fscale)) != sizeof(fscale)) 82 goto bad; 83 nelem = MIN(nelem, sizeof(averunnable) / sizeof(averunnable[0])); 84 for (i = 0; i < nelem; i++) 85 loadavg[i] = (double) averunnable[i] / fscale; 86 if (!alreadyopen) 87 kvm_close(); 88 return (nelem); 89 90 bad: 91 if (!alreadyopen) 92 kvm_close(); 93 return (-1); 94 } 95