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[] = "@(#)getloadavg.c 6.2 (Berkeley) 6/29/90"; 36 #endif /* LIBC_SCCS and not lint */ 37 38 #include <sys/param.h> 39 #include <sys/types.h> 40 #include <sys/file.h> 41 #include <nlist.h> 42 43 static struct nlist nl[] = { 44 { "_averunnable" }, 45 #define X_AVERUNNABLE 0 46 { "_fscale" }, 47 #define X_FSCALE 1 48 { "" }, 49 }; 50 51 /* 52 * getloadavg() -- Get system load averages. 53 * 54 * Put `nelem' samples into `loadavg' array. 55 * Return number of samples retrieved, or -1 on error. 56 */ 57 getloadavg(loadavg, nelem) 58 double loadavg[]; 59 int nelem; 60 { 61 static int need_nlist = 1; 62 fixpt_t averunnable[3]; 63 int fscale, kmemfd, i; 64 int alreadyopen; 65 66 if ((alreadyopen = kvm_openfiles(NULL, NULL, NULL)) == -1) 67 return (-1); 68 /* 69 * cache nlist 70 */ 71 if (need_nlist) { 72 if (kvm_nlist(nl) != 0) 73 goto bad; 74 need_nlist = 0; 75 } 76 if (kvm_read((off_t)nl[X_AVERUNNABLE].n_value, (char *)averunnable, 77 sizeof(averunnable)) != sizeof(averunnable)) 78 goto bad; 79 if (kvm_read( (off_t)nl[X_FSCALE].n_value, (char *)&fscale, 80 sizeof(fscale)) != sizeof(fscale)) 81 goto bad; 82 nelem = MIN(nelem, sizeof(averunnable) / sizeof(averunnable[0])); 83 for (i = 0; i < nelem; i++) 84 loadavg[i] = (double) averunnable[i] / fscale; 85 if (!alreadyopen) 86 kvm_close(); 87 return (nelem); 88 89 bad: 90 if (!alreadyopen) 91 kvm_close(); 92 return (-1); 93 } 94