mirror of https://github.com/dzavalishin/oskit/
84 lines
2.3 KiB
C
84 lines
2.3 KiB
C
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/*
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* Copyright (c) 1996-1998 University of Utah and the Flux Group.
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* All rights reserved.
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*
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* This file is part of the Flux OSKit. The OSKit is free software, also known
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* as "open source;" you can redistribute it and/or modify it under the terms
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* of the GNU General Public License (GPL), version 2, as published by the Free
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* Software Foundation (FSF). To explore alternate licensing terms, contact
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* the University of Utah at csl-dist@cs.utah.edu or +1-801-585-3271.
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*
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* The OSKit is distributed in the hope that it will be useful, but WITHOUT ANY
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* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GPL for more details. You should have
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* received a copy of the GPL along with the OSKit; see the file COPYING. If
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* not, write to the FSF, 59 Temple Place #330, Boston, MA 02111-1307, USA.
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*/
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/*
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* Select (isolate) a range of address space
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*/
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#include <errno.h>
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#include "amm.h"
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/*
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* Select (isolate) the specified range by splitting off everything before
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* and after as necessary. Result is one or more entries exactly covering
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* the range. Returns a pointer to the first entry for the start of the
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* range or zero if the range could not be isolated. Successive entries
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* can be located using amm_find_addr.
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*/
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amm_entry_t *
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amm_select(struct amm *amm, oskit_addr_t addr, oskit_size_t size)
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{
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struct amm_entry **pentry, *entry, *hentry, *tentry;
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oskit_addr_t eaddr;
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int rc;
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eaddr = addr + size;
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if (eaddr < addr)
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return 0;
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entry = amm_find_addr(amm, addr);
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pentry = amm->hint;
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/*
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* Split off anything before the region of interest.
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* Leave hint pointing at the beginning of the region.
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*/
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if (entry->start < addr) {
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rc = amm_split(amm, pentry, entry, addr, &hentry, &tentry);
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if (rc)
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return 0;
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pentry = &hentry->next;
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entry = tentry;
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amm->hint = pentry;
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}
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assert(entry->start == addr);
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/*
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* Skip over entries that are completely covered by the range.
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*/
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while (entry->end < eaddr) {
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pentry = &entry->next;
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entry = *pentry;
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}
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/*
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* Split off anything after the region of interest
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*/
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if (entry->end > eaddr) {
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rc = amm_split(amm, pentry, entry, eaddr, &hentry, &tentry);
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if (rc)
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return 0;
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entry = hentry;
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}
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assert(entry->end == eaddr);
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/*
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* Return the first entry.
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*/
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return *amm->hint;
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}
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