/* $Id: alloc-posix.cpp 4071 2007-08-07 17:07:59Z vboxsync $ */ /** @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. */ /******************************************************************************* * Header Files * *******************************************************************************/ #include #include #include #include #include #include #include #include #include #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