1 /* $OpenBSD: uvm_unix.c,v 1.68 2020/07/06 13:33:09 pirofti Exp $ */ 2 /* $NetBSD: uvm_unix.c,v 1.18 2000/09/13 15:00:25 thorpej Exp $ */ 3 4 /* 5 * Copyright (c) 1997 Charles D. Cranor and Washington University. 6 * Copyright (c) 1991, 1993 The Regents of the University of California. 7 * Copyright (c) 1988 University of Utah. 8 * 9 * All rights reserved. 10 * 11 * This code is derived from software contributed to Berkeley by 12 * the Systems Programming Group of the University of Utah Computer 13 * Science Department. 14 * 15 * Redistribution and use in source and binary forms, with or without 16 * modification, are permitted provided that the following conditions 17 * are met: 18 * 1. Redistributions of source code must retain the above copyright 19 * notice, this list of conditions and the following disclaimer. 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in the 22 * documentation and/or other materials provided with the distribution. 23 * 3. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 * 39 * from: Utah $Hdr: vm_unix.c 1.1 89/11/07$ 40 * @(#)vm_unix.c 8.1 (Berkeley) 6/11/93 41 * from: Id: uvm_unix.c,v 1.1.2.2 1997/08/25 18:52:30 chuck Exp 42 */ 43 44 /* 45 * uvm_unix.c: traditional sbrk/grow interface to vm. 46 */ 47 48 #include <sys/param.h> 49 #include <sys/systm.h> 50 #include <sys/proc.h> 51 #include <sys/resourcevar.h> 52 #include <sys/vnode.h> 53 54 #include <sys/mount.h> 55 #include <sys/syscallargs.h> 56 57 #include <uvm/uvm.h> 58 59 /* 60 * sys_obreak: set break 61 */ 62 63 int 64 sys_obreak(struct proc *p, void *v, register_t *retval) 65 { 66 struct sys_obreak_args /* { 67 syscallarg(char *) nsize; 68 } */ *uap = v; 69 struct vmspace *vm = p->p_vmspace; 70 vaddr_t new, old, base; 71 int error; 72 73 base = (vaddr_t)vm->vm_daddr; 74 new = round_page((vaddr_t)SCARG(uap, nsize)); 75 if (new < base || (new - base) > lim_cur(RLIMIT_DATA)) 76 return (ENOMEM); 77 78 old = round_page(base + ptoa(vm->vm_dsize)); 79 80 if (new == old) 81 return (0); 82 83 /* grow or shrink? */ 84 if (new > old) { 85 error = uvm_map(&vm->vm_map, &old, new - old, NULL, 86 UVM_UNKNOWN_OFFSET, 0, 87 UVM_MAPFLAG(PROT_READ | PROT_WRITE, 88 PROT_READ | PROT_WRITE | PROT_EXEC, MAP_INHERIT_COPY, 89 MADV_NORMAL, UVM_FLAG_FIXED|UVM_FLAG_COPYONW)); 90 if (error) { 91 uprintf("sbrk: grow %ld failed, error = %d\n", 92 new - old, error); 93 return (ENOMEM); 94 } 95 vm->vm_dsize += atop(new - old); 96 } else { 97 uvm_unmap(&vm->vm_map, new, old); 98 vm->vm_dsize -= atop(old - new); 99 } 100 101 return (0); 102 } 103 104 /* 105 * uvm_grow: enlarge the "stack segment" to include sp. 106 */ 107 void 108 uvm_grow(struct proc *p, vaddr_t sp) 109 { 110 struct vmspace *vm = p->p_vmspace; 111 int si; 112 113 /* For user defined stacks (from sendsig). */ 114 if (sp < (vaddr_t)vm->vm_maxsaddr) 115 return; 116 117 /* For common case of already allocated (from trap). */ 118 #ifdef MACHINE_STACK_GROWS_UP 119 if (sp < (vaddr_t)vm->vm_maxsaddr + ptoa(vm->vm_ssize)) 120 #else 121 if (sp >= (vaddr_t)vm->vm_minsaddr - ptoa(vm->vm_ssize)) 122 #endif 123 return; 124 125 /* Really need to check vs limit and increment stack size if ok. */ 126 #ifdef MACHINE_STACK_GROWS_UP 127 si = atop(sp - (vaddr_t)vm->vm_maxsaddr) - vm->vm_ssize + 1; 128 #else 129 si = atop((vaddr_t)vm->vm_minsaddr - sp) - vm->vm_ssize; 130 #endif 131 if (vm->vm_ssize + si <= atop(lim_cur(RLIMIT_STACK))) 132 vm->vm_ssize += si; 133 } 134 135 #ifndef SMALL_KERNEL 136 137 #define WALK_CHUNK 32 138 /* 139 * Not all the pages in an amap may be present. When dumping core, 140 * we don't want to force all the pages to be present: it's a waste 141 * of time and memory when we already know what they contain (zeros) 142 * and the ELF format at least can adequately represent them as a 143 * segment with memory size larger than its file size. 144 * 145 * So, we walk the amap with calls to amap_lookups() and scan the 146 * resulting pointers to find ranges of zero or more present pages 147 * followed by at least one absent page or the end of the amap. 148 * When then pass that range to the walk callback with 'start' 149 * pointing to the start of the present range, 'realend' pointing 150 * to the first absent page (or the end of the entry), and 'end' 151 * pointing to the page page the last absent page (or the end of 152 * the entry). 153 * 154 * Note that if the first page of the amap is empty then the callback 155 * must be invoked with 'start' == 'realend' so it can present that 156 * first range of absent pages. 157 */ 158 int 159 uvm_coredump_walk_amap(struct vm_map_entry *entry, int *nsegmentp, 160 uvm_coredump_walk_cb *walk, void *cookie) 161 { 162 struct vm_anon *anons[WALK_CHUNK]; 163 vaddr_t pos, start, realend, end, entry_end; 164 vm_prot_t prot; 165 int nsegment, absent, npages, i, error; 166 167 prot = entry->protection; 168 nsegment = *nsegmentp; 169 start = entry->start; 170 entry_end = MIN(entry->end, VM_MAXUSER_ADDRESS); 171 172 absent = 0; 173 for (pos = start; pos < entry_end; pos += npages << PAGE_SHIFT) { 174 npages = (entry_end - pos) >> PAGE_SHIFT; 175 if (npages > WALK_CHUNK) 176 npages = WALK_CHUNK; 177 amap_lookups(&entry->aref, pos - entry->start, anons, npages); 178 for (i = 0; i < npages; i++) { 179 if ((anons[i] == NULL) == absent) 180 continue; 181 if (!absent) { 182 /* going from present to absent: set realend */ 183 realend = pos + (i << PAGE_SHIFT); 184 absent = 1; 185 continue; 186 } 187 188 /* going from absent to present: invoke callback */ 189 end = pos + (i << PAGE_SHIFT); 190 if (start != end) { 191 error = (*walk)(start, realend, end, prot, 192 nsegment, cookie); 193 if (error) 194 return error; 195 nsegment++; 196 } 197 start = realend = end; 198 absent = 0; 199 } 200 } 201 202 if (!absent) 203 realend = entry_end; 204 error = (*walk)(start, realend, entry_end, prot, nsegment, cookie); 205 *nsegmentp = nsegment + 1; 206 return error; 207 } 208 209 /* 210 * Common logic for whether a map entry should be included in a coredump 211 */ 212 static inline int 213 uvm_should_coredump(struct proc *p, struct vm_map_entry *entry) 214 { 215 if (!(entry->protection & PROT_WRITE) && 216 entry->aref.ar_amap == NULL && 217 entry->start != p->p_p->ps_sigcode && 218 entry->start != p->p_p->ps_timekeep) 219 return 0; 220 221 /* 222 * Skip ranges marked as unreadable, as uiomove(UIO_USERSPACE) 223 * will fail on them. Maybe this really should be a test of 224 * entry->max_protection, but doing 225 * uvm_map_extract(UVM_EXTRACT_FIXPROT) 226 * on each such page would suck. 227 */ 228 if ((entry->protection & PROT_READ) == 0) 229 return 0; 230 231 /* Skip ranges excluded from coredumps. */ 232 if (UVM_ET_ISCONCEAL(entry)) 233 return 0; 234 235 /* Don't dump mmaped devices. */ 236 if (entry->object.uvm_obj != NULL && 237 UVM_OBJ_IS_DEVICE(entry->object.uvm_obj)) 238 return 0; 239 240 if (entry->start >= VM_MAXUSER_ADDRESS) 241 return 0; 242 243 return 1; 244 } 245 246 247 /* do nothing callback for uvm_coredump_walk_amap() */ 248 static int 249 noop(vaddr_t start, vaddr_t realend, vaddr_t end, vm_prot_t prot, 250 int nsegment, void *cookie) 251 { 252 return 0; 253 } 254 255 /* 256 * Walk the VA space for a process to identify what to write to 257 * a coredump. First the number of contiguous ranges is counted, 258 * then the 'setup' callback is invoked to prepare for actually 259 * recording the ranges, then the VA is walked again, invoking 260 * the 'walk' callback for each range. The number of ranges walked 261 * is guaranteed to match the count seen by the 'setup' callback. 262 */ 263 264 int 265 uvm_coredump_walkmap(struct proc *p, uvm_coredump_setup_cb *setup, 266 uvm_coredump_walk_cb *walk, void *cookie) 267 { 268 struct vmspace *vm = p->p_vmspace; 269 struct vm_map *map = &vm->vm_map; 270 struct vm_map_entry *entry; 271 vaddr_t end; 272 int refed_amaps = 0; 273 int nsegment, error; 274 275 /* 276 * Walk the map once to count the segments. If an amap is 277 * referenced more than once than take *another* reference 278 * and treat the amap as exactly one segment instead of 279 * checking page presence inside it. On the second pass 280 * we'll recognize which amaps we did that for by the ref 281 * count being >1...and decrement it then. 282 */ 283 nsegment = 0; 284 RBT_FOREACH(entry, uvm_map_addr, &map->addr) { 285 /* should never happen for a user process */ 286 if (UVM_ET_ISSUBMAP(entry)) { 287 panic("%s: user process with submap?", __func__); 288 } 289 290 if (! uvm_should_coredump(p, entry)) 291 continue; 292 293 if (entry->aref.ar_amap != NULL) { 294 if (entry->aref.ar_amap->am_ref == 1) { 295 uvm_coredump_walk_amap(entry, &nsegment, 296 &noop, cookie); 297 continue; 298 } 299 300 /* 301 * Multiple refs currently, so take another and 302 * treat it as a single segment 303 */ 304 entry->aref.ar_amap->am_ref++; 305 refed_amaps++; 306 } 307 308 nsegment++; 309 } 310 311 /* 312 * Okay, we have a count in nsegment. Prepare to 313 * walk it again, then invoke the setup callback. 314 */ 315 entry = RBT_MIN(uvm_map_addr, &map->addr); 316 error = (*setup)(nsegment, cookie); 317 if (error) 318 goto cleanup; 319 320 /* 321 * Setup went okay, so do the second walk, invoking the walk 322 * callback on the counted segments and cleaning up references 323 * as we go. 324 */ 325 nsegment = 0; 326 for (; entry != NULL; entry = RBT_NEXT(uvm_map_addr, entry)) { 327 if (! uvm_should_coredump(p, entry)) 328 continue; 329 330 if (entry->aref.ar_amap != NULL && 331 entry->aref.ar_amap->am_ref == 1) { 332 error = uvm_coredump_walk_amap(entry, &nsegment, 333 walk, cookie); 334 if (error) 335 break; 336 continue; 337 } 338 339 end = entry->end; 340 if (end > VM_MAXUSER_ADDRESS) 341 end = VM_MAXUSER_ADDRESS; 342 343 error = (*walk)(entry->start, end, end, entry->protection, 344 nsegment, cookie); 345 if (error) 346 break; 347 nsegment++; 348 349 if (entry->aref.ar_amap != NULL && 350 entry->aref.ar_amap->am_ref > 1) { 351 /* multiple refs, so we need to drop one */ 352 entry->aref.ar_amap->am_ref--; 353 refed_amaps--; 354 } 355 } 356 357 if (error) { 358 cleanup: 359 /* clean up the extra references from where we left off */ 360 if (refed_amaps > 0) { 361 for (; entry != NULL; 362 entry = RBT_NEXT(uvm_map_addr, entry)) { 363 if (entry->aref.ar_amap == NULL || 364 entry->aref.ar_amap->am_ref == 1) 365 continue; 366 if (! uvm_should_coredump(p, entry)) 367 continue; 368 entry->aref.ar_amap->am_ref--; 369 if (refed_amaps-- == 0) 370 break; 371 } 372 } 373 } 374 375 return error; 376 } 377 378 #endif /* !SMALL_KERNEL */ 379