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143 lines
3.5 KiB
C
143 lines
3.5 KiB
C
/*-
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* See the file LICENSE for redistribution information.
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*
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* Copyright (c) 1996-2004
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* Sleepycat Software. All rights reserved.
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*
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* $Id: os_region.c,v 11.21 2004/06/10 17:20:57 bostic Exp $
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*/
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#include "db_config.h"
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#ifndef NO_SYSTEM_INCLUDES
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#include <sys/types.h>
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#include <string.h>
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#endif
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#include "db_int.h"
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/*
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* __os_r_attach --
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* Attach to a shared memory region.
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*
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* PUBLIC: int __os_r_attach __P((DB_ENV *, REGINFO *, REGION *));
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*/
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int
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__os_r_attach(dbenv, infop, rp)
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DB_ENV *dbenv;
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REGINFO *infop;
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REGION *rp;
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{
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int ret;
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/* Round off the requested size for the underlying VM. */
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OS_VMROUNDOFF(rp->size);
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#ifdef DB_REGIONSIZE_MAX
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/* Some architectures have hard limits on the maximum region size. */
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if (rp->size > DB_REGIONSIZE_MAX) {
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__db_err(dbenv, "region size %lu is too large; maximum is %lu",
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(u_long)rp->size, (u_long)DB_REGIONSIZE_MAX);
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return (EINVAL);
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}
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#endif
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/*
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* If a region is private, malloc the memory.
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*
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* !!!
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* If this fails because the region is too large to malloc, mmap(2)
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* using the MAP_ANON or MAP_ANONYMOUS flags would be an alternative.
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* I don't know of any architectures (yet!) where malloc is a problem.
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*/
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if (F_ISSET(dbenv, DB_ENV_PRIVATE)) {
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#if defined(MUTEX_NO_MALLOC_LOCKS)
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/*
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* !!!
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* There exist spinlocks that don't work in malloc memory, e.g.,
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* the HP/UX msemaphore interface. If we don't have locks that
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* will work in malloc memory, we better not be private or not
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* be threaded.
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*/
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if (F_ISSET(dbenv, DB_ENV_THREAD)) {
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__db_err(dbenv, "%s",
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"architecture does not support locks inside process-local (malloc) memory");
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__db_err(dbenv, "%s",
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"application may not specify both DB_PRIVATE and DB_THREAD");
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return (EINVAL);
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}
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#endif
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/*
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* Pad out the allocation, we're going to align it to mutex
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* alignment.
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*/
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if ((ret = __os_malloc(dbenv,
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sizeof(REGENV) + (MUTEX_ALIGN - 1), &infop->addr)) != 0)
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return (ret);
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infop->max_alloc = rp->size;
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} else {
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/*
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* If the user replaced the map call, call through their
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* interface.
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*/
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if (DB_GLOBAL(j_map) != NULL && (ret = DB_GLOBAL(j_map)
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(infop->name, rp->size, 1, 0, &infop->addr)) != 0)
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return (ret);
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/* Get some space from the underlying system. */
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if ((ret = __os_r_sysattach(dbenv, infop, rp)) != 0)
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return (ret);
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}
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/*
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* We may require alignment the underlying system or heap allocation
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* library doesn't supply. Align the address if necessary, saving
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* the original values for restoration when the region is discarded.
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*/
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infop->addr_orig = infop->addr;
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infop->addr = ALIGNP_INC(infop->addr_orig, MUTEX_ALIGN);
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rp->size_orig = rp->size;
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if (infop->addr != infop->addr_orig)
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rp->size -=
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(u_int8_t *)infop->addr - (u_int8_t *)infop->addr_orig;
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return (0);
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}
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/*
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* __os_r_detach --
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* Detach from a shared memory region.
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*
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* PUBLIC: int __os_r_detach __P((DB_ENV *, REGINFO *, int));
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*/
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int
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__os_r_detach(dbenv, infop, destroy)
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DB_ENV *dbenv;
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REGINFO *infop;
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int destroy;
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{
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REGION *rp;
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rp = infop->rp;
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/* Restore any address/size altered for alignment reasons. */
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if (infop->addr != infop->addr_orig) {
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infop->addr = infop->addr_orig;
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rp->size = rp->size_orig;
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}
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/* If a region is private, free the memory. */
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if (F_ISSET(dbenv, DB_ENV_PRIVATE)) {
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__os_free(dbenv, infop->addr);
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return (0);
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}
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/* If the user replaced the map call, call through their interface. */
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if (DB_GLOBAL(j_unmap) != NULL)
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return (DB_GLOBAL(j_unmap)(infop->addr, rp->size));
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return (__os_r_sysdetach(dbenv, infop, destroy));
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}
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