1 /* 2 * (MPSAFE) 3 * 4 * Copyright (c) 1988 University of Utah. 5 * Copyright (c) 1991, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * the Systems Programming Group of the University of Utah Computer 10 * Science Department. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * from: Utah $Hdr: vm_unix.c 1.1 89/11/07$ 37 * 38 * @(#)vm_unix.c 8.1 (Berkeley) 6/11/93 39 * $FreeBSD: src/sys/vm/vm_unix.c,v 1.24.2.2 2002/07/02 20:06:19 dillon Exp $ 40 * $DragonFly: src/sys/vm/vm_unix.c,v 1.7 2006/11/07 17:51:24 dillon Exp $ 41 */ 42 43 /* 44 * Traditional sbrk/grow interface to VM 45 */ 46 #include <sys/param.h> 47 #include <sys/sysproto.h> 48 #include <sys/proc.h> 49 #include <sys/resourcevar.h> 50 51 #include <vm/vm.h> 52 #include <vm/vm_param.h> 53 #include <sys/lock.h> 54 #include <vm/pmap.h> 55 #include <vm/vm_map.h> 56 57 #include <sys/thread.h> 58 59 /* 60 * sys_obreak backs the C library sbrk call 61 * 62 * obreak_args(char *nsize) 63 * 64 * No requirements. 65 */ 66 int 67 sys_obreak(struct obreak_args *uap) 68 { 69 struct proc *p = curproc; 70 struct vmspace *vm = p->p_vmspace; 71 vm_offset_t new, old, base; 72 int rv; 73 int error; 74 75 error = 0; 76 77 lwkt_gettoken(&vm->vm_map.token); 78 79 base = round_page((vm_offset_t)vm->vm_daddr); 80 new = round_page((vm_offset_t)uap->nsize); 81 old = base + ctob(vm->vm_dsize); 82 83 if (new > base) { 84 /* 85 * We check resource limits here, but alow processes to 86 * reduce their usage, even if they remain over the limit. 87 */ 88 if (new > old && 89 (new - base) > (vm_offset_t) p->p_rlimit[RLIMIT_DATA].rlim_cur) { 90 error = ENOMEM; 91 goto done; 92 } 93 if (new >= VM_MAX_USER_ADDRESS) { 94 error = ENOMEM; 95 goto done; 96 } 97 } else if (new < base) { 98 /* 99 * This is simply an invalid value. If someone wants to 100 * do fancy address space manipulations, mmap and munmap 101 * can do most of what the user would want. 102 */ 103 error = EINVAL; 104 goto done; 105 } 106 107 if (new > old) { 108 vm_size_t diff; 109 110 diff = new - old; 111 if (vm->vm_map.size + diff > p->p_rlimit[RLIMIT_VMEM].rlim_cur) { 112 error = ENOMEM; 113 goto done; 114 } 115 rv = vm_map_find(&vm->vm_map, NULL, NULL, 116 0, &old, diff, 117 PAGE_SIZE, FALSE, 118 VM_MAPTYPE_NORMAL, VM_SUBSYS_BRK, 119 VM_PROT_ALL, VM_PROT_ALL, 0); 120 if (rv != KERN_SUCCESS) { 121 error = ENOMEM; 122 goto done; 123 } 124 if (vm->vm_map.flags & MAP_WIREFUTURE) 125 vm_map_wire(&vm->vm_map, old, new, FALSE); 126 127 vm->vm_dsize += btoc(diff); 128 } else if (new < old) { 129 rv = vm_map_remove(&vm->vm_map, new, old); 130 if (rv != KERN_SUCCESS) { 131 error = ENOMEM; 132 goto done; 133 } 134 vm->vm_dsize -= btoc(old - new); 135 } 136 done: 137 lwkt_reltoken(&vm->vm_map.token); 138 139 return (error); 140 } 141