alloc-posix.cpp revision a4d7fc6f54717c342281099fe14f5666be9b7921
/* $Id$ */
/** @file
* innotek Portable Runtime - Memory Allocation, POSIX.
*/
/*
* Copyright (C) 2006-2007 innotek GmbH
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* you can redistribute it and/or modify it under the terms of the GNU
* General Public License as published by the Free Software Foundation,
* in version 2 as it comes in the "COPYING" file of the VirtualBox OSE
* distribution. VirtualBox OSE is distributed in the hope that it will
* be useful, but WITHOUT ANY WARRANTY of any kind.
*
* If you received this file as part of a commercial VirtualBox
* distribution, then only the terms of your commercial VirtualBox
* license agreement apply instead of the previous paragraph.
*/
/*******************************************************************************
* Header Files *
*******************************************************************************/
#include <iprt/alloc.h>
#include <iprt/assert.h>
#include <iprt/param.h>
#include <iprt/err.h>
#include <iprt/string.h>
#include <stdlib.h>
#include <malloc.h>
#include <errno.h>
#include <sys/mman.h>
#if !defined(RT_USE_MMAP) && (defined(RT_OS_LINUX))
# define RT_USE_MMAP
#endif
/*******************************************************************************
* Structures and Typedefs *
*******************************************************************************/
#ifdef RT_USE_MMAP
/**
* RTMemExecAlloc() header used when using mmap for allocating the memory.
*/
typedef struct RTMEMEXECHDR
{
/** Magic number (RTMEMEXECHDR_MAGIC). */
size_t uMagic;
/** The size we requested from mmap. */
size_t cb;
# if ARCH_BITS == 32
uint32_t Alignment[2];
# endif
} RTMEMEXECHDR, *PRTMEMEXECHDR;
/** Magic for RTMEMEXECHDR. */
#define RTMEMEXECHDR_MAGIC (~(size_t)0xfeedbabe)
#endif /* RT_USE_MMAP */
#ifdef IN_RING3
/**
* Allocates memory which may contain code.
*
* @returns Pointer to the allocated memory.
* @returns NULL on failure.
* @param cb Size in bytes of the memory block to allocate.
*/
RTDECL(void *) RTMemExecAlloc(size_t cb)
{
AssertMsg(cb, ("Allocating ZERO bytes is really not a good idea! Good luck with the next assertion!\n"));
#ifdef RT_USE_MMAP
/*
* Use mmap to get low memory.
*/
size_t cbAlloc = RT_ALIGN_Z(cb + sizeof(RTMEMEXECHDR), PAGE_SIZE);
void *pv = mmap(NULL, cbAlloc, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE | MAP_ANONYMOUS
#if defined(RT_ARCH_AMD64) && defined(MAP_32BIT)
| MAP_32BIT
#endif
, -1, 0);
AssertMsgReturn(pv != MAP_FAILED, ("errno=%d cb=%#zx\n", errno, cb), NULL);
PRTMEMEXECHDR pHdr = (PRTMEMEXECHDR)pv;
pHdr->uMagic = RTMEMEXECHDR_MAGIC;
pHdr->cb = cbAlloc;
pv = pHdr + 1;
#else
/*
* Allocate first.
*/
cb = RT_ALIGN_Z(cb, 32);
void *pv = NULL;
int rc = posix_memalign(&pv, 32, cb);
AssertMsg(!rc && pv, ("posix_memalign(%zd) failed!!! rc=%d\n", cb, rc));
if (pv && !rc)
{
/*
* Add PROT_EXEC flag to the page.
*
* This is in violation of the SuS where I think it saith that mprotect() shall
* only be used with mmap()'ed memory. Works on linux and OS/2 LIBC v0.6.
*/
memset(pv, 0xcc, cb);
void *pvProt = (void *)((uintptr_t)pv & ~PAGE_OFFSET_MASK);
size_t cbProt = ((uintptr_t)pv & PAGE_OFFSET_MASK) + cb;
cbProt = RT_ALIGN_Z(cbProt, PAGE_SIZE);
rc = mprotect(pvProt, cbProt, PROT_READ | PROT_WRITE | PROT_EXEC);
if (rc)
{
AssertMsgFailed(("mprotect(%p, %#zx,,) -> rc=%d, errno=%d\n", pvProt, cbProt, rc, errno));
free(pv);
pv = NULL;
}
}
#endif
return pv;
}
/**
* Free executable/read/write memory allocated by RTMemExecAlloc().
*
* @param pv Pointer to memory block.
*/
RTDECL(void) RTMemExecFree(void *pv)
{
if (pv)
{
#ifdef RT_USE_MMAP
PRTMEMEXECHDR pHdr = (PRTMEMEXECHDR)pv - 1;
AssertMsgReturnVoid(RT_ALIGN_P(pHdr, PAGE_SIZE) == pHdr, ("pHdr=%p pv=%p\n", pHdr, pv));
AssertMsgReturnVoid(pHdr->uMagic == RTMEMEXECHDR_MAGIC, ("pHdr=%p(uMagic=%#zx) pv=%p\n", pHdr, pHdr->uMagic, pv));
int rc = munmap(pHdr, pHdr->cb);
AssertMsg(!rc, ("munmap -> %d errno=%d\n", rc, errno)); NOREF(rc);
#else
free(pv);
#endif
}
}
/**
* Allocate page aligned memory.
*
* @returns Pointer to the allocated memory.
* @returns NULL if we're out of memory.
* @param cb Size of the memory block. Will be rounded up to page size.
*/
RTDECL(void *) RTMemPageAlloc(size_t cb)
{
#if 0 /** @todo huh? we're using posix_memalign in the next function... */
void *pv;
int rc = posix_memalign(&pv, PAGE_SIZE, RT_ALIGN_Z(cb, PAGE_SIZE));
if (!rc)
return pv;
return NULL;
#else
return memalign(PAGE_SIZE, cb);
#endif
}
/**
* Allocate zero'ed page aligned memory.
*
* @returns Pointer to the allocated memory.
* @returns NULL if we're out of memory.
* @param cb Size of the memory block. Will be rounded up to page size.
*/
RTDECL(void *) RTMemPageAllocZ(size_t cb)
{
void *pv;
int rc = posix_memalign(&pv, PAGE_SIZE, RT_ALIGN_Z(cb, PAGE_SIZE));
if (!rc)
{
bzero(pv, RT_ALIGN_Z(cb, PAGE_SIZE));
return pv;
}
return NULL;
}
/**
* Free a memory block allocated with RTMemPageAlloc() or RTMemPageAllocZ().
*
* @param pv Pointer to the block as it was returned by the allocation function.
* NULL will be ignored.
*/
RTDECL(void) RTMemPageFree(void *pv)
{
if (pv)
free(pv);
}
/**
* Change the page level protection of a memory region.
*
* @returns iprt status code.
* @param pv Start of the region. Will be rounded down to nearest page boundary.
* @param cb Size of the region. Will be rounded up to the nearest page boundary.
* @param fProtect The new protection, a combination of the RTMEM_PROT_* defines.
*/
RTDECL(int) RTMemProtect(void *pv, size_t cb, unsigned fProtect)
{
/*
* Validate input.
*/
if (cb == 0)
{
AssertMsgFailed(("!cb\n"));
return VERR_INVALID_PARAMETER;
}
if (fProtect & ~(RTMEM_PROT_NONE | RTMEM_PROT_READ | RTMEM_PROT_WRITE | RTMEM_PROT_EXEC))
{
AssertMsgFailed(("fProtect=%#x\n", fProtect));
return VERR_INVALID_PARAMETER;
}
/*
* Convert the flags.
*/
int fProt;
#if RTMEM_PROT_NONE == PROT_NONE \
&& RTMEM_PROT_READ == PROT_READ \
&& RTMEM_PROT_WRITE == PROT_WRITE \
&& RTMEM_PROT_EXEC == PROT_EXEC
fProt = fProtect;
#else
Assert(!RTMEM_PROT_NONE);
if (!fProtect)
fProt = PROT_NONE;
else
{
fProt = 0;
if (fProtect & RTMEM_PROT_READ)
fProt |= PROT_READ;
if (fProtect & RTMEM_PROT_WRITE)
fProt |= PROT_WRITE;
if (fProtect & RTMEM_PROT_EXEC)
fProt |= PROT_EXEC;
}
#endif
/*
* Align the request.
*/
cb += (uintptr_t)pv & PAGE_OFFSET_MASK;
pv = (void *)((uintptr_t)pv & ~PAGE_OFFSET_MASK);
/*
* Change the page attributes.
*/
int rc = mprotect(pv, cb, fProt);
if (!rc)
return rc;
return RTErrConvertFromErrno(errno);
}
#endif