/* $OpenBSD: uvm_unix.c,v 1.71 2020/10/21 21:24:57 deraadt Exp $ */ /* $NetBSD: uvm_unix.c,v 1.18 2000/09/13 15:00:25 thorpej Exp $ */ /* * Copyright (c) 1997 Charles D. Cranor and Washington University. * Copyright (c) 1991, 1993 The Regents of the University of California. * Copyright (c) 1988 University of Utah. * * 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 * from: Id: uvm_unix.c,v 1.1.2.2 1997/08/25 18:52:30 chuck Exp */ /* * uvm_unix.c: traditional sbrk/grow interface to vm. */ #include #include #include #include #include #include #include #include /* * sys_obreak: set break */ int sys_obreak(struct proc *p, void *v, register_t *retval) { struct sys_obreak_args /* { syscallarg(char *) nsize; } */ *uap = v; struct vmspace *vm = p->p_vmspace; vaddr_t new, old, base; int error; base = (vaddr_t)vm->vm_daddr; new = round_page((vaddr_t)SCARG(uap, nsize)); if (new < base || (new - base) > lim_cur(RLIMIT_DATA)) return (ENOMEM); old = round_page(base + ptoa(vm->vm_dsize)); if (new == old) return (0); /* grow or shrink? */ if (new > old) { error = uvm_map(&vm->vm_map, &old, new - old, NULL, UVM_UNKNOWN_OFFSET, 0, UVM_MAPFLAG(PROT_READ | PROT_WRITE, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_INHERIT_COPY, MADV_NORMAL, UVM_FLAG_FIXED|UVM_FLAG_COPYONW)); if (error) { uprintf("sbrk: grow %ld failed, error = %d\n", new - old, error); return (ENOMEM); } vm->vm_dsize += atop(new - old); } else { uvm_unmap(&vm->vm_map, new, old); vm->vm_dsize -= atop(old - new); } return (0); } /* * uvm_grow: enlarge the "stack segment" to include sp. */ void uvm_grow(struct proc *p, vaddr_t sp) { struct vmspace *vm = p->p_vmspace; vm_map_t map = &vm->vm_map; int si; /* For user defined stacks (from sendsig). */ if (sp < (vaddr_t)vm->vm_maxsaddr) return; #ifdef MACHINE_STACK_GROWS_UP if (sp >= (vaddr_t)vm->vm_minsaddr) return; #endif vm_map_lock(map); /* For common case of already allocated (from trap). */ #ifdef MACHINE_STACK_GROWS_UP if (sp < (vaddr_t)vm->vm_maxsaddr + ptoa(vm->vm_ssize)) #else if (sp >= (vaddr_t)vm->vm_minsaddr - ptoa(vm->vm_ssize)) #endif goto out; /* Really need to check vs limit and increment stack size if ok. */ #ifdef MACHINE_STACK_GROWS_UP si = atop(sp - (vaddr_t)vm->vm_maxsaddr) - vm->vm_ssize + 1; #else si = atop((vaddr_t)vm->vm_minsaddr - sp) - vm->vm_ssize; #endif if (vm->vm_ssize + si <= atop(lim_cur(RLIMIT_STACK))) vm->vm_ssize += si; out: vm_map_unlock(map); } #ifndef SMALL_KERNEL #define WALK_CHUNK 32 /* * Not all the pages in an amap may be present. When dumping core, * we don't want to force all the pages to be present: it's a waste * of time and memory when we already know what they contain (zeros) * and the ELF format at least can adequately represent them as a * segment with memory size larger than its file size. * * So, we walk the amap with calls to amap_lookups() and scan the * resulting pointers to find ranges of zero or more present pages * followed by at least one absent page or the end of the amap. * When then pass that range to the walk callback with 'start' * pointing to the start of the present range, 'realend' pointing * to the first absent page (or the end of the entry), and 'end' * pointing to the page past the last absent page (or the end of * the entry). * * Note that if the first page of the amap is empty then the callback * must be invoked with 'start' == 'realend' so it can present that * first range of absent pages. */ int uvm_coredump_walk_amap(struct vm_map_entry *entry, int *nsegmentp, uvm_coredump_walk_cb *walk, void *cookie) { struct vm_anon *anons[WALK_CHUNK]; vaddr_t pos, start, realend, end, entry_end; vm_prot_t prot; int nsegment, absent, npages, i, error; prot = entry->protection; nsegment = *nsegmentp; start = entry->start; entry_end = MIN(entry->end, VM_MAXUSER_ADDRESS); absent = 0; for (pos = start; pos < entry_end; pos += npages << PAGE_SHIFT) { npages = (entry_end - pos) >> PAGE_SHIFT; if (npages > WALK_CHUNK) npages = WALK_CHUNK; amap_lookups(&entry->aref, pos - entry->start, anons, npages); for (i = 0; i < npages; i++) { if ((anons[i] == NULL) == absent) continue; if (!absent) { /* going from present to absent: set realend */ realend = pos + (i << PAGE_SHIFT); absent = 1; continue; } /* going from absent to present: invoke callback */ end = pos + (i << PAGE_SHIFT); if (start != end) { error = (*walk)(start, realend, end, prot, nsegment, cookie); if (error) return error; nsegment++; } start = realend = end; absent = 0; } } if (!absent) realend = entry_end; error = (*walk)(start, realend, entry_end, prot, nsegment, cookie); *nsegmentp = nsegment + 1; return error; } /* * Common logic for whether a map entry should be included in a coredump */ static inline int uvm_should_coredump(struct proc *p, struct vm_map_entry *entry) { if (!(entry->protection & PROT_WRITE) && entry->aref.ar_amap == NULL && entry->start != p->p_p->ps_sigcode && entry->start != p->p_p->ps_timekeep) return 0; /* * Skip ranges marked as unreadable, as uiomove(UIO_USERSPACE) * will fail on them. Maybe this really should be a test of * entry->max_protection, but doing * uvm_map_extract(UVM_EXTRACT_FIXPROT) * on each such page would suck. */ if ((entry->protection & PROT_READ) == 0) return 0; /* Skip ranges excluded from coredumps. */ if (UVM_ET_ISCONCEAL(entry)) return 0; /* Don't dump mmaped devices. */ if (entry->object.uvm_obj != NULL && UVM_OBJ_IS_DEVICE(entry->object.uvm_obj)) return 0; if (entry->start >= VM_MAXUSER_ADDRESS) return 0; return 1; } /* do nothing callback for uvm_coredump_walk_amap() */ static int noop(vaddr_t start, vaddr_t realend, vaddr_t end, vm_prot_t prot, int nsegment, void *cookie) { return 0; } /* * Walk the VA space for a process to identify what to write to * a coredump. First the number of contiguous ranges is counted, * then the 'setup' callback is invoked to prepare for actually * recording the ranges, then the VA is walked again, invoking * the 'walk' callback for each range. The number of ranges walked * is guaranteed to match the count seen by the 'setup' callback. */ int uvm_coredump_walkmap(struct proc *p, uvm_coredump_setup_cb *setup, uvm_coredump_walk_cb *walk, void *cookie) { struct vmspace *vm = p->p_vmspace; struct vm_map *map = &vm->vm_map; struct vm_map_entry *entry; vaddr_t end; int refed_amaps = 0; int nsegment, error; /* * Walk the map once to count the segments. If an amap is * referenced more than once than take *another* reference * and treat the amap as exactly one segment instead of * checking page presence inside it. On the second pass * we'll recognize which amaps we did that for by the ref * count being >1...and decrement it then. */ nsegment = 0; RBT_FOREACH(entry, uvm_map_addr, &map->addr) { /* should never happen for a user process */ if (UVM_ET_ISSUBMAP(entry)) { panic("%s: user process with submap?", __func__); } if (! uvm_should_coredump(p, entry)) continue; if (entry->aref.ar_amap != NULL) { if (entry->aref.ar_amap->am_ref == 1) { uvm_coredump_walk_amap(entry, &nsegment, &noop, cookie); continue; } /* * Multiple refs currently, so take another and * treat it as a single segment */ entry->aref.ar_amap->am_ref++; refed_amaps++; } nsegment++; } /* * Okay, we have a count in nsegment. Prepare to * walk it again, then invoke the setup callback. */ entry = RBT_MIN(uvm_map_addr, &map->addr); error = (*setup)(nsegment, cookie); if (error) goto cleanup; /* * Setup went okay, so do the second walk, invoking the walk * callback on the counted segments and cleaning up references * as we go. */ nsegment = 0; for (; entry != NULL; entry = RBT_NEXT(uvm_map_addr, entry)) { if (! uvm_should_coredump(p, entry)) continue; if (entry->aref.ar_amap != NULL && entry->aref.ar_amap->am_ref == 1) { error = uvm_coredump_walk_amap(entry, &nsegment, walk, cookie); if (error) break; continue; } end = entry->end; if (end > VM_MAXUSER_ADDRESS) end = VM_MAXUSER_ADDRESS; error = (*walk)(entry->start, end, end, entry->protection, nsegment, cookie); if (error) break; nsegment++; if (entry->aref.ar_amap != NULL && entry->aref.ar_amap->am_ref > 1) { /* multiple refs, so we need to drop one */ entry->aref.ar_amap->am_ref--; refed_amaps--; } } if (error) { cleanup: /* clean up the extra references from where we left off */ if (refed_amaps > 0) { for (; entry != NULL; entry = RBT_NEXT(uvm_map_addr, entry)) { if (entry->aref.ar_amap == NULL || entry->aref.ar_amap->am_ref == 1) continue; if (! uvm_should_coredump(p, entry)) continue; entry->aref.ar_amap->am_ref--; if (refed_amaps-- == 0) break; } } } return error; } #endif /* !SMALL_KERNEL */