178 lines
3.8 KiB
C
178 lines
3.8 KiB
C
/* $NetBSD: page.c,v 1.2 2003/12/04 16:23:34 drochner Exp $ */
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include "efence.h"
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/mman.h>
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#include <stdio.h>
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#include <errno.h>
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#include <string.h>
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/*
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* Lots of systems are missing the definition of PROT_NONE.
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*/
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#ifndef PROT_NONE
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#define PROT_NONE 0
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#endif
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/*
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* 386 BSD has MAP_ANON instead of MAP_ANONYMOUS.
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*/
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#if ( !defined(MAP_ANONYMOUS) && defined(MAP_ANON) )
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#define MAP_ANONYMOUS MAP_ANON
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#endif
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/*
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* For some reason, I can't find mprotect() in any of the headers on
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* IRIX or SunOS 4.1.2
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*/
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/* extern C_LINKAGE int mprotect(void * addr, size_t len, int prot); */
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static caddr_t startAddr = (caddr_t) 0;
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static const char *
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stringErrorReport(void)
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{
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return strerror(errno);
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}
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/*
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* Create memory.
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*/
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#if defined(MAP_ANONYMOUS)
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void *
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Page_Create(size_t size)
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{
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caddr_t allocation;
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/*
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* In this version, "startAddr" is a _hint_, not a demand.
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* When the memory I map here is contiguous with other
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* mappings, the allocator can coalesce the memory from two
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* or more mappings into one large contiguous chunk, and thus
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* might be able to find a fit that would not otherwise have
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* been possible. I could _force_ it to be contiguous by using
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* the MMAP_FIXED flag, but I don't want to stomp on memory mappings
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* generated by other software, etc.
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*/
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allocation = (caddr_t) mmap(
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startAddr
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,(int)size
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,PROT_READ|PROT_WRITE
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,MAP_PRIVATE|MAP_ANONYMOUS
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,-1
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,0);
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#ifndef __hpux
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/*
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* Set the "address hint" for the next mmap() so that it will abut
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* the mapping we just created.
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*
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* HP/UX 9.01 has a kernel bug that makes mmap() fail sometimes
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* when given a non-zero address hint, so we'll leave the hint set
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* to zero on that system. HP recently told me this is now fixed.
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* Someone please tell me when it is probable to assume that most
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* of those systems that were running 9.01 have been upgraded.
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*/
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startAddr = allocation + size;
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#endif
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if ( allocation == (caddr_t)-1 )
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EF_Exit("mmap() failed: %s", stringErrorReport());
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return (void *)allocation;
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}
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#else
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void *
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Page_Create(size_t size)
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{
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static int devZeroFd = -1;
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caddr_t allocation;
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if ( devZeroFd == -1 ) {
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devZeroFd = open("/dev/zero", O_RDWR);
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if ( devZeroFd < 0 )
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EF_Exit(
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"open() on /dev/zero failed: %s"
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,stringErrorReport());
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}
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/*
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* In this version, "startAddr" is a _hint_, not a demand.
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* When the memory I map here is contiguous with other
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* mappings, the allocator can coalesce the memory from two
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* or more mappings into one large contiguous chunk, and thus
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* might be able to find a fit that would not otherwise have
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* been possible. I could _force_ it to be contiguous by using
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* the MMAP_FIXED flag, but I don't want to stomp on memory mappings
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* generated by other software, etc.
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*/
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allocation = (caddr_t) mmap(
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startAddr
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,(int)size
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,PROT_READ|PROT_WRITE
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,MAP_PRIVATE
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,devZeroFd
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,0);
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startAddr = allocation + size;
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if ( allocation == (caddr_t)-1 )
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EF_Exit("mmap() failed: %s", stringErrorReport());
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return (void *)allocation;
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}
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#endif
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static void
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mprotectFailed(void)
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{
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EF_Exit("mprotect() failed: %s", stringErrorReport());
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}
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void
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Page_AllowAccess(void * address, size_t size)
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{
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if ( mprotect((caddr_t)address, size, PROT_READ|PROT_WRITE) < 0 )
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mprotectFailed();
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}
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void
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Page_DenyAccess(void * address, size_t size)
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{
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if ( mprotect((caddr_t)address, size, PROT_NONE) < 0 )
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mprotectFailed();
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}
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void
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Page_Delete(void * address, size_t size)
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{
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if ( munmap((caddr_t)address, size) < 0 )
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Page_DenyAccess(address, size);
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}
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#if defined(_SC_PAGESIZE)
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size_t
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Page_Size(void)
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{
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return (size_t)sysconf(_SC_PAGESIZE);
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}
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#elif defined(_SC_PAGE_SIZE)
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size_t
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Page_Size(void)
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{
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return (size_t)sysconf(_SC_PAGE_SIZE);
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}
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#else
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/* extern int getpagesize(); */
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size_t
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Page_Size(void)
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{
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return getpagesize();
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}
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#endif
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