| 1 | /* $Id: alloc-posix.cpp 27492 2010-03-18 16:56:32Z vboxsync $ */
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| 2 | /** @file
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| 3 | * IPRT - Memory Allocation, POSIX.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2006-2007 Sun Microsystems, Inc.
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| 8 | *
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| 9 | * This file is part of VirtualBox Open Source Edition (OSE), as
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| 10 | * available from http://www.virtualbox.org. This file is free software;
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| 11 | * you can redistribute it and/or modify it under the terms of the GNU
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| 12 | * General Public License (GPL) as published by the Free Software
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| 13 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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| 14 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 15 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 16 | *
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| 17 | * The contents of this file may alternatively be used under the terms
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| 18 | * of the Common Development and Distribution License Version 1.0
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| 19 | * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
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| 20 | * VirtualBox OSE distribution, in which case the provisions of the
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| 21 | * CDDL are applicable instead of those of the GPL.
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| 22 | *
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| 23 | * You may elect to license modified versions of this file under the
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| 24 | * terms and conditions of either the GPL or the CDDL or both.
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| 25 | *
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| 26 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
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| 27 | * Clara, CA 95054 USA or visit http://www.sun.com if you need
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| 28 | * additional information or have any questions.
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| 29 | */
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| 30 |
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| 31 |
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| 32 | /*******************************************************************************
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| 33 | * Header Files *
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| 34 | *******************************************************************************/
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| 35 | #include <iprt/alloc.h>
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| 36 | #include <iprt/assert.h>
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| 37 | #include <iprt/param.h>
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| 38 | #include <iprt/err.h>
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| 39 | #include <iprt/string.h>
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| 40 |
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| 41 | #include <stdlib.h>
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| 42 | #include <malloc.h>
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| 43 | #include <errno.h>
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| 44 | #include <sys/mman.h>
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| 45 |
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| 46 | #if !defined(RT_USE_MMAP) && (defined(RT_OS_LINUX))
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| 47 | # define RT_USE_MMAP
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| 48 | #endif
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| 49 |
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| 50 | /*******************************************************************************
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| 51 | * Structures and Typedefs *
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| 52 | *******************************************************************************/
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| 53 | #ifdef RT_USE_MMAP
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| 54 | /**
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| 55 | * RTMemExecAlloc() header used when using mmap for allocating the memory.
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| 56 | */
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| 57 | typedef struct RTMEMEXECHDR
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| 58 | {
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| 59 | /** Magic number (RTMEMEXECHDR_MAGIC). */
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| 60 | size_t uMagic;
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| 61 | /** The size we requested from mmap. */
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| 62 | size_t cb;
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| 63 | # if ARCH_BITS == 32
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| 64 | uint32_t Alignment[2];
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| 65 | # endif
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| 66 | } RTMEMEXECHDR, *PRTMEMEXECHDR;
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| 67 |
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| 68 | /** Magic for RTMEMEXECHDR. */
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| 69 | #define RTMEMEXECHDR_MAGIC (~(size_t)0xfeedbabe)
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| 70 |
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| 71 | #endif /* RT_USE_MMAP */
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| 72 |
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| 73 |
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| 74 |
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| 75 | /**
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| 76 | * Allocates memory which may contain code.
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| 77 | *
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| 78 | * @returns Pointer to the allocated memory.
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| 79 | * @returns NULL on failure.
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| 80 | * @param cb Size in bytes of the memory block to allocate.
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| 81 | */
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| 82 | RTDECL(void *) RTMemExecAlloc(size_t cb) RT_NO_THROW
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| 83 | {
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| 84 | AssertMsg(cb, ("Allocating ZERO bytes is really not a good idea! Good luck with the next assertion!\n"));
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| 85 |
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| 86 | #ifdef RT_USE_MMAP
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| 87 | /*
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| 88 | * Use mmap to get low memory.
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| 89 | */
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| 90 | size_t cbAlloc = RT_ALIGN_Z(cb + sizeof(RTMEMEXECHDR), PAGE_SIZE);
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| 91 | void *pv = mmap(NULL, cbAlloc, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE | MAP_ANONYMOUS
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| 92 | #if defined(RT_ARCH_AMD64) && defined(MAP_32BIT)
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| 93 | | MAP_32BIT
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| 94 | #endif
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| 95 | , -1, 0);
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| 96 | AssertMsgReturn(pv != MAP_FAILED, ("errno=%d cb=%#zx\n", errno, cb), NULL);
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| 97 | PRTMEMEXECHDR pHdr = (PRTMEMEXECHDR)pv;
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| 98 | pHdr->uMagic = RTMEMEXECHDR_MAGIC;
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| 99 | pHdr->cb = cbAlloc;
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| 100 | pv = pHdr + 1;
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| 101 |
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| 102 | #else
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| 103 | /*
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| 104 | * Allocate first.
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| 105 | */
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| 106 | cb = RT_ALIGN_Z(cb, 32);
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| 107 | void *pv = NULL;
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| 108 | int rc = posix_memalign(&pv, 32, cb);
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| 109 | AssertMsg(!rc && pv, ("posix_memalign(%zd) failed!!! rc=%d\n", cb, rc));
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| 110 | if (pv && !rc)
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| 111 | {
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| 112 | /*
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| 113 | * Add PROT_EXEC flag to the page.
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| 114 | *
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| 115 | * This is in violation of the SuS where I think it saith that mprotect() shall
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| 116 | * only be used with mmap()'ed memory. Works on linux and OS/2 LIBC v0.6.
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| 117 | */
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| 118 | memset(pv, 0xcc, cb);
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| 119 | void *pvProt = (void *)((uintptr_t)pv & ~PAGE_OFFSET_MASK);
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| 120 | size_t cbProt = ((uintptr_t)pv & PAGE_OFFSET_MASK) + cb;
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| 121 | cbProt = RT_ALIGN_Z(cbProt, PAGE_SIZE);
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| 122 | rc = mprotect(pvProt, cbProt, PROT_READ | PROT_WRITE | PROT_EXEC);
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| 123 | if (rc)
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| 124 | {
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| 125 | AssertMsgFailed(("mprotect(%p, %#zx,,) -> rc=%d, errno=%d\n", pvProt, cbProt, rc, errno));
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| 126 | free(pv);
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| 127 | pv = NULL;
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| 128 | }
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| 129 | }
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| 130 | #endif
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| 131 | return pv;
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| 132 | }
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| 133 |
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| 134 |
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| 135 | /**
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| 136 | * Free executable/read/write memory allocated by RTMemExecAlloc().
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| 137 | *
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| 138 | * @param pv Pointer to memory block.
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| 139 | */
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| 140 | RTDECL(void) RTMemExecFree(void *pv) RT_NO_THROW
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| 141 | {
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| 142 | if (pv)
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| 143 | {
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| 144 | #ifdef RT_USE_MMAP
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| 145 | PRTMEMEXECHDR pHdr = (PRTMEMEXECHDR)pv - 1;
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| 146 | AssertMsgReturnVoid(RT_ALIGN_P(pHdr, PAGE_SIZE) == pHdr, ("pHdr=%p pv=%p\n", pHdr, pv));
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| 147 | AssertMsgReturnVoid(pHdr->uMagic == RTMEMEXECHDR_MAGIC, ("pHdr=%p(uMagic=%#zx) pv=%p\n", pHdr, pHdr->uMagic, pv));
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| 148 | int rc = munmap(pHdr, pHdr->cb);
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| 149 | AssertMsg(!rc, ("munmap -> %d errno=%d\n", rc, errno)); NOREF(rc);
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| 150 | #else
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| 151 | free(pv);
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| 152 | #endif
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| 153 | }
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| 154 | }
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| 155 |
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| 156 |
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| 157 | /**
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| 158 | * Allocate page aligned memory.
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| 159 | *
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| 160 | * @returns Pointer to the allocated memory.
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| 161 | * @returns NULL if we're out of memory.
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| 162 | * @param cb Size of the memory block. Will be rounded up to page size.
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| 163 | */
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| 164 | RTDECL(void *) RTMemPageAlloc(size_t cb) RT_NO_THROW
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| 165 | {
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| 166 | #if 0 /** @todo huh? we're using posix_memalign in the next function... */
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| 167 | void *pv;
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| 168 | int rc = posix_memalign(&pv, PAGE_SIZE, RT_ALIGN_Z(cb, PAGE_SIZE));
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| 169 | if (!rc)
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| 170 | return pv;
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| 171 | return NULL;
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| 172 | #else
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| 173 | return memalign(PAGE_SIZE, cb);
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| 174 | #endif
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| 175 | }
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| 176 |
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| 177 |
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| 178 | /**
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| 179 | * Allocate zero'ed page aligned memory.
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| 180 | *
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| 181 | * @returns Pointer to the allocated memory.
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| 182 | * @returns NULL if we're out of memory.
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| 183 | * @param cb Size of the memory block. Will be rounded up to page size.
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| 184 | */
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| 185 | RTDECL(void *) RTMemPageAllocZ(size_t cb) RT_NO_THROW
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| 186 | {
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| 187 | void *pv;
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| 188 | int rc = posix_memalign(&pv, PAGE_SIZE, RT_ALIGN_Z(cb, PAGE_SIZE));
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| 189 | if (!rc)
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| 190 | {
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| 191 | bzero(pv, RT_ALIGN_Z(cb, PAGE_SIZE));
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| 192 | return pv;
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| 193 | }
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| 194 | return NULL;
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| 195 | }
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| 196 |
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| 197 |
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| 198 | /**
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| 199 | * Free a memory block allocated with RTMemPageAlloc() or RTMemPageAllocZ().
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| 200 | *
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| 201 | * @param pv Pointer to the block as it was returned by the allocation function.
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| 202 | * NULL will be ignored.
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| 203 | */
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| 204 | RTDECL(void) RTMemPageFree(void *pv) RT_NO_THROW
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| 205 | {
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| 206 | if (pv)
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| 207 | free(pv);
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| 208 | }
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| 209 |
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| 210 |
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| 211 | /**
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| 212 | * Change the page level protection of a memory region.
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| 213 | *
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| 214 | * @returns iprt status code.
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| 215 | * @param pv Start of the region. Will be rounded down to nearest page boundary.
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| 216 | * @param cb Size of the region. Will be rounded up to the nearest page boundary.
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| 217 | * @param fProtect The new protection, a combination of the RTMEM_PROT_* defines.
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| 218 | */
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| 219 | RTDECL(int) RTMemProtect(void *pv, size_t cb, unsigned fProtect) RT_NO_THROW
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| 220 | {
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| 221 | /*
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| 222 | * Validate input.
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| 223 | */
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| 224 | if (cb == 0)
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| 225 | {
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| 226 | AssertMsgFailed(("!cb\n"));
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| 227 | return VERR_INVALID_PARAMETER;
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| 228 | }
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| 229 | if (fProtect & ~(RTMEM_PROT_NONE | RTMEM_PROT_READ | RTMEM_PROT_WRITE | RTMEM_PROT_EXEC))
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| 230 | {
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| 231 | AssertMsgFailed(("fProtect=%#x\n", fProtect));
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| 232 | return VERR_INVALID_PARAMETER;
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| 233 | }
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| 234 |
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| 235 | /*
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| 236 | * Convert the flags.
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| 237 | */
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| 238 | int fProt;
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| 239 | #if RTMEM_PROT_NONE == PROT_NONE \
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| 240 | && RTMEM_PROT_READ == PROT_READ \
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| 241 | && RTMEM_PROT_WRITE == PROT_WRITE \
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| 242 | && RTMEM_PROT_EXEC == PROT_EXEC
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| 243 | fProt = fProtect;
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| 244 | #else
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| 245 | Assert(!RTMEM_PROT_NONE);
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| 246 | if (!fProtect)
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| 247 | fProt = PROT_NONE;
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| 248 | else
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| 249 | {
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| 250 | fProt = 0;
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| 251 | if (fProtect & RTMEM_PROT_READ)
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| 252 | fProt |= PROT_READ;
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| 253 | if (fProtect & RTMEM_PROT_WRITE)
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| 254 | fProt |= PROT_WRITE;
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| 255 | if (fProtect & RTMEM_PROT_EXEC)
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| 256 | fProt |= PROT_EXEC;
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| 257 | }
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| 258 | #endif
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| 259 |
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| 260 | /*
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| 261 | * Align the request.
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| 262 | */
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| 263 | cb += (uintptr_t)pv & PAGE_OFFSET_MASK;
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| 264 | pv = (void *)((uintptr_t)pv & ~PAGE_OFFSET_MASK);
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| 265 |
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| 266 | /*
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| 267 | * Change the page attributes.
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| 268 | */
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| 269 | int rc = mprotect(pv, cb, fProt);
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| 270 | if (!rc)
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| 271 | return rc;
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| 272 | return RTErrConvertFromErrno(errno);
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| 273 | }
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