/* * (MPSAFE) * * Copyright (c) 1988 University of Utah. * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * the Systems Programming Group of the University of Utah Computer * Science Department. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * from: Utah $Hdr: vm_unix.c 1.1 89/11/07$ * * @(#)vm_unix.c 8.1 (Berkeley) 6/11/93 * $FreeBSD: src/sys/vm/vm_unix.c,v 1.24.2.2 2002/07/02 20:06:19 dillon Exp $ * $DragonFly: src/sys/vm/vm_unix.c,v 1.7 2006/11/07 17:51:24 dillon Exp $ */ /* * Traditional sbrk/grow interface to VM */ #include <sys/param.h> #include <sys/sysmsg.h> #include <sys/proc.h> #include <sys/resourcevar.h> #include <vm/vm.h> #include <vm/vm_param.h> #include <sys/lock.h> #include <vm/pmap.h> #include <vm/vm_map.h> #include <sys/thread.h> /* * sys_sbrk backs the C library sbrk call * * void *sbrk(intptr_t incr) * * No requirements. */ int sys_sbrk(struct sysmsg *sysmsg, const struct sbrk_args *uap) { struct proc *p = curproc; struct vmspace *vm = p->p_vmspace; vm_offset_t nbase; vm_offset_t base; vm_offset_t base_end; vm_offset_t incr; int rv; int error; error = 0; lwkt_gettoken(&vm->vm_map.token); /* * Cannot assume that last data page for binary is mapped R/W. */ base = round_page((vm_offset_t)vm->vm_daddr) + vm->vm_dsize; incr = uap->incr; /* * Cannot allow space to be freed with sbrk() because it is not * thread-safe for userland and because unrelated mmap()s can reside * in the data space if the DATA rlimit is raised on the running * program. */ if (incr < 0) { error = EOPNOTSUPP; goto done; } /* * Userland requests current base */ if (incr == 0) { sysmsg->sysmsg_resultp = (void *)base; goto done; } /* * Calculate approximate area (vm_map_find() may change this). * Check for overflow, address space, and rlimit caps. */ base_end = base + incr; if (base_end >= VM_MAX_USER_ADDRESS) { error = ENOMEM; goto done; } if (base_end < base || base_end - (vm_offset_t)vm->vm_daddr > (vm_offset_t)p->p_rlimit[RLIMIT_DATA].rlim_cur) { error = ENOMEM; goto done; } /* * Same-page optimization (protected by token) */ if ((base & PAGE_MASK) != 0 && ((base ^ (base_end - 1)) & ~(vm_offset_t)PAGE_MASK) == 0) { sysmsg->sysmsg_resultp = (void *)base; vm->vm_dsize += incr; goto done; } /* * Formally map more space */ nbase = round_page(base); rv = vm_map_find(&vm->vm_map, NULL, NULL, 0, &nbase, round_page(incr), PAGE_SIZE, FALSE, VM_MAPTYPE_NORMAL, VM_SUBSYS_BRK, VM_PROT_ALL, VM_PROT_ALL, 0); if (rv != KERN_SUCCESS) { error = ENOMEM; goto done; } base_end = nbase + round_page(incr); sysmsg->sysmsg_resultp = (void *)nbase; /* wire the pages */ if (vm->vm_map.flags & MAP_WIREFUTURE) vm_map_kernel_wiring(&vm->vm_map, base, base_end, 0); /* * Adjust dsize upwards only */ incr = nbase + incr - round_page((vm_offset_t)vm->vm_daddr); if (vm->vm_dsize < incr) vm->vm_dsize = incr; done: lwkt_reltoken(&vm->vm_map.token); return (error); } /* * sys_obreak is used by the sbrk emulation code in libc when sbrk() * is not supported. * * obreak_args(char *nsize) * * No requirements. */ int sys_obreak(struct sysmsg *sysmsg, const struct obreak_args *uap) { struct proc *p = curproc; struct vmspace *vm = p->p_vmspace; vm_offset_t new, old, base; int rv; int error; error = 0; lwkt_gettoken(&vm->vm_map.token); base = round_page((vm_offset_t)vm->vm_daddr); new = round_page((vm_offset_t)uap->nsize); old = base + round_page(vm->vm_dsize); if (new > base) { /* * We check resource limits here, but alow processes to * reduce their usage, even if they remain over the limit. */ if (new > old && (new - base) > (vm_offset_t) p->p_rlimit[RLIMIT_DATA].rlim_cur) { error = ENOMEM; goto done; } if (new >= VM_MAX_USER_ADDRESS) { error = ENOMEM; goto done; } } else if (new < base) { /* * This is simply an invalid value. If someone wants to * do fancy address space manipulations, mmap and munmap * can do most of what the user would want. */ error = EINVAL; goto done; } if (new > old) { vm_size_t diff; diff = new - old; if (vm->vm_map.size + diff > p->p_rlimit[RLIMIT_VMEM].rlim_cur) { error = ENOMEM; goto done; } rv = vm_map_find(&vm->vm_map, NULL, NULL, 0, &old, diff, PAGE_SIZE, FALSE, VM_MAPTYPE_NORMAL, VM_SUBSYS_BRK, VM_PROT_ALL, VM_PROT_ALL, 0); if (rv != KERN_SUCCESS) { error = ENOMEM; goto done; } /* wire the pages */ if (vm->vm_map.flags & MAP_WIREFUTURE) vm_map_kernel_wiring(&vm->vm_map, old, new, 0); vm->vm_dsize += diff; } else if (new < old) { error = EOPNOTSUPP; #if 0 rv = vm_map_remove(&vm->vm_map, new, old); if (rv != KERN_SUCCESS) { error = ENOMEM; goto done; } vm->vm_dsize -= old - new; #endif } done: lwkt_reltoken(&vm->vm_map.token); return (error); }
