1*0Sstevel@tonic-gate /* 2*0Sstevel@tonic-gate * CDDL HEADER START 3*0Sstevel@tonic-gate * 4*0Sstevel@tonic-gate * The contents of this file are subject to the terms of the 5*0Sstevel@tonic-gate * Common Development and Distribution License, Version 1.0 only 6*0Sstevel@tonic-gate * (the "License"). You may not use this file except in compliance 7*0Sstevel@tonic-gate * with the License. 8*0Sstevel@tonic-gate * 9*0Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10*0Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing. 11*0Sstevel@tonic-gate * See the License for the specific language governing permissions 12*0Sstevel@tonic-gate * and limitations under the License. 13*0Sstevel@tonic-gate * 14*0Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each 15*0Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16*0Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the 17*0Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying 18*0Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner] 19*0Sstevel@tonic-gate * 20*0Sstevel@tonic-gate * CDDL HEADER END 21*0Sstevel@tonic-gate */ 22*0Sstevel@tonic-gate /* 23*0Sstevel@tonic-gate * Copyright (c) 1991-2001 by Sun Microsystems, Inc. 24*0Sstevel@tonic-gate * All rights reserved. 25*0Sstevel@tonic-gate */ 26*0Sstevel@tonic-gate 27*0Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI" 28*0Sstevel@tonic-gate 29*0Sstevel@tonic-gate /* 30*0Sstevel@tonic-gate * zmalloc - use mmap(2) to allocate memory from /dev/zero. 31*0Sstevel@tonic-gate * zfree - use munmap(2) to unmap (free) memory. 32*0Sstevel@tonic-gate * 33*0Sstevel@tonic-gate * These functions should be better than malloc(3) for large memory allocation. 34*0Sstevel@tonic-gate */ 35*0Sstevel@tonic-gate 36*0Sstevel@tonic-gate #include <stdio.h> 37*0Sstevel@tonic-gate #include <stdlib.h> 38*0Sstevel@tonic-gate #include <fcntl.h> 39*0Sstevel@tonic-gate #include <unistd.h> 40*0Sstevel@tonic-gate #include <sys/types.h> 41*0Sstevel@tonic-gate #include <sys/mman.h> 42*0Sstevel@tonic-gate #include <sys/stat.h> 43*0Sstevel@tonic-gate 44*0Sstevel@tonic-gate #include <zmalloc.h> 45*0Sstevel@tonic-gate 46*0Sstevel@tonic-gate /* 47*0Sstevel@tonic-gate * a utility structure to keep track of the (possibly) multiple mmaps 48*0Sstevel@tonic-gate * that we have done... 49*0Sstevel@tonic-gate */ 50*0Sstevel@tonic-gate struct buffer_map { 51*0Sstevel@tonic-gate struct buffer_map *bm_next; 52*0Sstevel@tonic-gate char *bm_buffer; 53*0Sstevel@tonic-gate int bm_size; 54*0Sstevel@tonic-gate }; 55*0Sstevel@tonic-gate 56*0Sstevel@tonic-gate static void *bm_empty = (void *) ""; /* special buffer */ 57*0Sstevel@tonic-gate static struct buffer_map *bm_list; /* NULL by default */ 58*0Sstevel@tonic-gate 59*0Sstevel@tonic-gate static struct buffer_map * 60*0Sstevel@tonic-gate insert_bm(char *buf, size_t size) 61*0Sstevel@tonic-gate { 62*0Sstevel@tonic-gate struct buffer_map *bm; 63*0Sstevel@tonic-gate 64*0Sstevel@tonic-gate bm = (struct buffer_map *)malloc(sizeof (struct buffer_map)); 65*0Sstevel@tonic-gate bm->bm_buffer = buf; 66*0Sstevel@tonic-gate bm->bm_size = size; 67*0Sstevel@tonic-gate bm->bm_next = bm_list; 68*0Sstevel@tonic-gate 69*0Sstevel@tonic-gate bm_list = bm; 70*0Sstevel@tonic-gate 71*0Sstevel@tonic-gate return (bm_list); 72*0Sstevel@tonic-gate } 73*0Sstevel@tonic-gate 74*0Sstevel@tonic-gate static size_t 75*0Sstevel@tonic-gate delete_bm(char *buf) 76*0Sstevel@tonic-gate { 77*0Sstevel@tonic-gate size_t size; 78*0Sstevel@tonic-gate register struct buffer_map *p_curr; 79*0Sstevel@tonic-gate register struct buffer_map *p_prev; 80*0Sstevel@tonic-gate 81*0Sstevel@tonic-gate p_prev = NULL; 82*0Sstevel@tonic-gate p_curr = bm_list; 83*0Sstevel@tonic-gate while (p_curr != NULL) { 84*0Sstevel@tonic-gate if (p_curr->bm_buffer == buf) { 85*0Sstevel@tonic-gate if (p_prev == NULL) 86*0Sstevel@tonic-gate bm_list = p_curr->bm_next; 87*0Sstevel@tonic-gate else 88*0Sstevel@tonic-gate p_prev->bm_next = p_curr->bm_next; 89*0Sstevel@tonic-gate size = p_curr->bm_size; 90*0Sstevel@tonic-gate free(p_curr); 91*0Sstevel@tonic-gate return (size); 92*0Sstevel@tonic-gate } 93*0Sstevel@tonic-gate 94*0Sstevel@tonic-gate p_prev = p_curr; 95*0Sstevel@tonic-gate p_curr = p_curr->bm_next; 96*0Sstevel@tonic-gate } 97*0Sstevel@tonic-gate return (0); 98*0Sstevel@tonic-gate } 99*0Sstevel@tonic-gate 100*0Sstevel@tonic-gate void * 101*0Sstevel@tonic-gate zmalloc(size_t size) 102*0Sstevel@tonic-gate { 103*0Sstevel@tonic-gate int fd; 104*0Sstevel@tonic-gate caddr_t mbuf; 105*0Sstevel@tonic-gate 106*0Sstevel@tonic-gate /* XXX - Special case: never allocate 0 bytes, use a special buffer */ 107*0Sstevel@tonic-gate if (size == 0) 108*0Sstevel@tonic-gate return ((void *)NULL); /* return (bm_empty); */ 109*0Sstevel@tonic-gate 110*0Sstevel@tonic-gate if ((fd = open("/dev/zero", O_RDWR)) < 0) { 111*0Sstevel@tonic-gate perror("/dev/zero"); 112*0Sstevel@tonic-gate return ((void *) NULL); 113*0Sstevel@tonic-gate } 114*0Sstevel@tonic-gate 115*0Sstevel@tonic-gate mbuf = mmap(0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); 116*0Sstevel@tonic-gate (void) close(fd); 117*0Sstevel@tonic-gate 118*0Sstevel@tonic-gate if (mbuf == (caddr_t)-1) { 119*0Sstevel@tonic-gate perror("zmalloc: mmap"); 120*0Sstevel@tonic-gate return ((void *) NULL); 121*0Sstevel@tonic-gate } 122*0Sstevel@tonic-gate 123*0Sstevel@tonic-gate (void) insert_bm(mbuf, size); 124*0Sstevel@tonic-gate 125*0Sstevel@tonic-gate return ((void *) mbuf); 126*0Sstevel@tonic-gate } 127*0Sstevel@tonic-gate 128*0Sstevel@tonic-gate void 129*0Sstevel@tonic-gate zfree(void* mbuf) 130*0Sstevel@tonic-gate { 131*0Sstevel@tonic-gate size_t size; 132*0Sstevel@tonic-gate 133*0Sstevel@tonic-gate if (mbuf == bm_empty) 134*0Sstevel@tonic-gate return; 135*0Sstevel@tonic-gate 136*0Sstevel@tonic-gate if (mbuf != NULL) { 137*0Sstevel@tonic-gate if (size = delete_bm((caddr_t)mbuf)) { 138*0Sstevel@tonic-gate if (munmap((char *)mbuf, size) < 0) 139*0Sstevel@tonic-gate perror("zfree: munmap"); 140*0Sstevel@tonic-gate } 141*0Sstevel@tonic-gate } 142*0Sstevel@tonic-gate } 143