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/sysmsg.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_sbrk backs the C library sbrk call 61 * 62 * void *sbrk(intptr_t incr) 63 * 64 * No requirements. 65 */ 66 int 67 sys_sbrk(struct sysmsg *sysmsg, const struct sbrk_args *uap) 68 { 69 struct proc *p = curproc; 70 struct vmspace *vm = p->p_vmspace; 71 vm_offset_t nbase; 72 vm_offset_t base; 73 vm_offset_t base_end; 74 vm_offset_t incr; 75 int rv; 76 int error; 77 78 error = 0; 79 80 lwkt_gettoken(&vm->vm_map.token); 81 82 /* 83 * Cannot assume that last data page for binary is mapped R/W. 84 */ 85 base = round_page((vm_offset_t)vm->vm_daddr) + vm->vm_dsize; 86 incr = uap->incr; 87 88 /* 89 * Cannot allow space to be freed with sbrk() because it is not 90 * thread-safe for userland and because unrelated mmap()s can reside 91 * in the data space if the DATA rlimit is raised on the running 92 * program. 93 */ 94 if (incr < 0) { 95 error = EOPNOTSUPP; 96 goto done; 97 } 98 99 /* 100 * Userland requests current base 101 */ 102 if (incr == 0) { 103 sysmsg->sysmsg_resultp = (void *)base; 104 goto done; 105 } 106 107 /* 108 * Calculate approximate area (vm_map_find() may change this). 109 * Check for overflow, address space, and rlimit caps. 110 */ 111 base_end = base + incr; 112 if (base_end >= VM_MAX_USER_ADDRESS) { 113 error = ENOMEM; 114 goto done; 115 } 116 if (base_end < base || 117 base_end - (vm_offset_t)vm->vm_daddr > 118 (vm_offset_t)p->p_rlimit[RLIMIT_DATA].rlim_cur) { 119 error = ENOMEM; 120 goto done; 121 } 122 123 /* 124 * Same-page optimization (protected by token) 125 */ 126 if ((base & PAGE_MASK) != 0 && 127 ((base ^ (base_end - 1)) & ~(vm_offset_t)PAGE_MASK) == 0) { 128 sysmsg->sysmsg_resultp = (void *)base; 129 vm->vm_dsize += incr; 130 goto done; 131 } 132 133 /* 134 * Formally map more space 135 */ 136 nbase = round_page(base); 137 rv = vm_map_find(&vm->vm_map, NULL, NULL, 138 0, &nbase, round_page(incr), 139 PAGE_SIZE, FALSE, 140 VM_MAPTYPE_NORMAL, VM_SUBSYS_BRK, 141 VM_PROT_ALL, VM_PROT_ALL, 0); 142 if (rv != KERN_SUCCESS) { 143 error = ENOMEM; 144 goto done; 145 } 146 base_end = nbase + round_page(incr); 147 sysmsg->sysmsg_resultp = (void *)nbase; 148 if (vm->vm_map.flags & MAP_WIREFUTURE) 149 vm_map_wire(&vm->vm_map, base, base_end, FALSE); 150 151 /* 152 * Adjust dsize upwards only 153 */ 154 incr = nbase + incr - round_page((vm_offset_t)vm->vm_daddr); 155 if (vm->vm_dsize < incr) 156 vm->vm_dsize = incr; 157 158 done: 159 lwkt_reltoken(&vm->vm_map.token); 160 161 return (error); 162 } 163 164 /* 165 * sys_obreak is used by the sbrk emulation code in libc when sbrk() 166 * is not supported. 167 * 168 * obreak_args(char *nsize) 169 * 170 * No requirements. 171 */ 172 int 173 sys_obreak(struct sysmsg *sysmsg, const struct obreak_args *uap) 174 { 175 struct proc *p = curproc; 176 struct vmspace *vm = p->p_vmspace; 177 vm_offset_t new, old, base; 178 int rv; 179 int error; 180 181 error = 0; 182 183 lwkt_gettoken(&vm->vm_map.token); 184 185 base = round_page((vm_offset_t)vm->vm_daddr); 186 new = round_page((vm_offset_t)uap->nsize); 187 old = base + round_page(vm->vm_dsize); 188 189 if (new > base) { 190 /* 191 * We check resource limits here, but alow processes to 192 * reduce their usage, even if they remain over the limit. 193 */ 194 if (new > old && 195 (new - base) > (vm_offset_t) p->p_rlimit[RLIMIT_DATA].rlim_cur) { 196 error = ENOMEM; 197 goto done; 198 } 199 if (new >= VM_MAX_USER_ADDRESS) { 200 error = ENOMEM; 201 goto done; 202 } 203 } else if (new < base) { 204 /* 205 * This is simply an invalid value. If someone wants to 206 * do fancy address space manipulations, mmap and munmap 207 * can do most of what the user would want. 208 */ 209 error = EINVAL; 210 goto done; 211 } 212 213 if (new > old) { 214 vm_size_t diff; 215 216 diff = new - old; 217 if (vm->vm_map.size + diff > p->p_rlimit[RLIMIT_VMEM].rlim_cur) { 218 error = ENOMEM; 219 goto done; 220 } 221 rv = vm_map_find(&vm->vm_map, NULL, NULL, 222 0, &old, diff, 223 PAGE_SIZE, FALSE, 224 VM_MAPTYPE_NORMAL, VM_SUBSYS_BRK, 225 VM_PROT_ALL, VM_PROT_ALL, 0); 226 if (rv != KERN_SUCCESS) { 227 error = ENOMEM; 228 goto done; 229 } 230 if (vm->vm_map.flags & MAP_WIREFUTURE) 231 vm_map_wire(&vm->vm_map, old, new, FALSE); 232 233 vm->vm_dsize += diff; 234 } else if (new < old) { 235 error = EOPNOTSUPP; 236 #if 0 237 rv = vm_map_remove(&vm->vm_map, new, old); 238 if (rv != KERN_SUCCESS) { 239 error = ENOMEM; 240 goto done; 241 } 242 vm->vm_dsize -= old - new; 243 #endif 244 } 245 done: 246 lwkt_reltoken(&vm->vm_map.token); 247 248 return (error); 249 } 250