| 1 | /* $Id: symlink-win.cpp 33437 2010-10-25 16:28:14Z vboxsync $ */
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| 2 | /** @file
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| 3 | * IPRT - Symbolic Links, Windows.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2010 Oracle Corporation
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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 |
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| 27 |
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| 28 | /*******************************************************************************
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| 29 | * Header Files *
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| 30 | *******************************************************************************/
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| 31 | #define LOG_GROUP RTLOGGROUP_SYMLINK
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| 32 |
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| 33 | #include <iprt/symlink.h>
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| 34 |
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| 35 | #include <iprt/assert.h>
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| 36 | #include <iprt/err.h>
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| 37 | #include <iprt/log.h>
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| 38 | #include <iprt/path.h>
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| 39 | #include <iprt/mem.h>
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| 40 | #include <iprt/string.h>
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| 41 | #include "internal/path.h"
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| 42 |
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| 43 | #include <Windows.h>
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| 44 |
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| 45 |
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| 46 | /*******************************************************************************
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| 47 | * Structures and Typedefs *
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| 48 | *******************************************************************************/
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| 49 | typedef struct MY_REPARSE_DATA_BUFFER
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| 50 | {
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| 51 | ULONG ReparseTag;
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| 52 | #define MY_IO_REPARSE_TAG_SYMLINK 0xa000000c
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| 53 | #define MY_IO_REPARSE_TAG_MOUNT_POINT 0xa0000003
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| 54 |
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| 55 | USHORT ReparseDataLength;
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| 56 | USHORT Reserved;
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| 57 | union
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| 58 | {
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| 59 | struct
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| 60 | {
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| 61 | USHORT SubstituteNameOffset;
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| 62 | USHORT SubstituteNameLength;
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| 63 | USHORT PrintNameOffset;
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| 64 | USHORT PrintNameLength;
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| 65 | ULONG Flags;
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| 66 | #define MY_SYMLINK_FLAG_RELATIVE 1
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| 67 | WCHAR PathBuffer[1];
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| 68 | } SymbolicLinkReparseBuffer;
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| 69 | struct
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| 70 | {
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| 71 | USHORT SubstituteNameOffset;
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| 72 | USHORT SubstituteNameLength;
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| 73 | USHORT PrintNameOffset;
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| 74 | USHORT PrintNameLength;
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| 75 | WCHAR PathBuffer[1];
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| 76 | } MountPointReparseBuffer;
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| 77 | struct
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| 78 | {
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| 79 | UCHAR DataBuffer[1];
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| 80 | } GenericReparseBuffer;
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| 81 | };
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| 82 | } MY_REPARSE_DATA_BUFFER;
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| 83 | #define MY_FSCTL_GET_REPARSE_POINT CTL_CODE(FILE_DEVICE_FILE_SYSTEM, 42, METHOD_BUFFERED, FILE_ANY_ACCESS)
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| 84 |
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| 85 |
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| 86 | RTDECL(bool) RTSymlinkExists(const char *pszSymlink)
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| 87 | {
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| 88 | bool fRc = false;
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| 89 | RTFSOBJINFO ObjInfo;
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| 90 | int rc = RTPathQueryInfoEx(pszSymlink, &ObjInfo, RTFSOBJATTRADD_NOTHING, RTPATH_F_ON_LINK);
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| 91 | if (RT_SUCCESS(rc))
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| 92 | fRc = RTFS_IS_SYMLINK(ObjInfo.Attr.fMode);
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| 93 |
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| 94 | LogFlow(("RTSymlinkExists(%p={%s}): returns %RTbool\n", pszSymlink, pszSymlink, fRc));
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| 95 | return fRc;
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| 96 | }
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| 97 |
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| 98 |
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| 99 | RTDECL(bool) RTSymlinkIsDangling(const char *pszSymlink)
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| 100 | {
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| 101 | bool fRc = false;
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| 102 | RTFSOBJINFO ObjInfo;
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| 103 | int rc = RTPathQueryInfoEx(pszSymlink, &ObjInfo, RTFSOBJATTRADD_NOTHING, RTPATH_F_ON_LINK);
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| 104 | if (RT_SUCCESS(rc))
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| 105 | {
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| 106 | fRc = RTFS_IS_SYMLINK(ObjInfo.Attr.fMode);
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| 107 | if (fRc)
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| 108 | {
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| 109 | rc = RTPathQueryInfoEx(pszSymlink, &ObjInfo, RTFSOBJATTRADD_NOTHING, RTPATH_F_FOLLOW_LINK);
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| 110 | fRc = !RT_SUCCESS_NP(rc);
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| 111 | }
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| 112 | }
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| 113 |
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| 114 | LogFlow(("RTSymlinkIsDangling(%p={%s}): returns %RTbool\n", pszSymlink, pszSymlink, fRc));
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| 115 | return fRc;
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| 116 | }
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| 117 |
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| 118 |
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| 119 | RTDECL(int) RTSymlinkCreate(const char *pszSymlink, const char *pszTarget, RTSYMLINKTYPE enmType)
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| 120 | {
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| 121 | /*
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| 122 | * Validate the input.
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| 123 | */
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| 124 | AssertReturn(enmType > RTSYMLINKTYPE_INVALID && enmType < RTSYMLINKTYPE_END, VERR_INVALID_PARAMETER);
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| 125 | AssertPtrReturn(pszSymlink, VERR_INVALID_POINTER);
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| 126 | AssertPtrReturn(pszTarget, VERR_INVALID_POINTER);
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| 127 |
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| 128 | /*
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| 129 | * Resolve the API.
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| 130 | */
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| 131 | typedef BOOLEAN (WINAPI *PFNCREATESYMBOLICLINKW)(LPCWSTR, LPCWSTR, DWORD);
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| 132 | static PFNCREATESYMBOLICLINKW s_pfnCreateSymbolicLinkW = NULL;
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| 133 | static bool s_fTried = FALSE;
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| 134 | if (!s_fTried)
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| 135 | {
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| 136 | HMODULE hmod = LoadLibrary("KERNEL32.DLL");
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| 137 | if (hmod)
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| 138 | {
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| 139 | PFNCREATESYMBOLICLINKW pfn = (PFNCREATESYMBOLICLINKW)GetProcAddress(hmod, "CreateSymbolicLinkW");
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| 140 | if (pfn)
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| 141 | s_pfnCreateSymbolicLinkW = pfn;
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| 142 | }
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| 143 | s_fTried = true;
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| 144 | }
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| 145 | if (!s_pfnCreateSymbolicLinkW)
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| 146 | {
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| 147 | LogFlow(("RTSymlinkCreate(%p={%s}, %p={%s}, %d): returns VERR_NOT_SUPPORTED - Windows API not found\n",
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| 148 | pszSymlink, pszSymlink, pszTarget, pszTarget, enmType));
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| 149 | return VERR_NOT_SUPPORTED;
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| 150 | }
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| 151 |
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| 152 | /*
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| 153 | * Convert the paths.
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| 154 | */
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| 155 | PRTUTF16 pwszNativeSymlink;
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| 156 | int rc = RTStrToUtf16(pszSymlink, &pwszNativeSymlink);
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| 157 | if (RT_SUCCESS(rc))
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| 158 | {
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| 159 | PRTUTF16 pwszNativeTarget;
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| 160 | rc = RTStrToUtf16(pszTarget, &pwszNativeTarget);
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| 161 | if (RT_SUCCESS(rc))
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| 162 | {
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| 163 | /*
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| 164 | * Massage the target path, determin the link type.
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| 165 | */
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| 166 | size_t cchTarget = strlen(pszTarget);
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| 167 | size_t cchVolSpecTarget = rtPathVolumeSpecLen(pszTarget);
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| 168 | #if 0 /* looks like this isn't needed after all. That makes everything much simper :-) */
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| 169 | if ( cchTarget > RT_MIN(cchVolSpecTarget, 1)
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| 170 | && RTPATH_IS_SLASH(pszTarget[cchTarget - 1]))
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| 171 | {
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| 172 | size_t cwcNativeTarget = RTUtf16Len(pwszNativeTarget);
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| 173 | size_t offFromEnd = 1;
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| 174 | while ( offFromEnd < cchTarget
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| 175 | && cchTarget - offFromEnd >= cchVolSpecTarget
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| 176 | && RTPATH_IS_SLASH(pszTarget[cchTarget - offFromEnd]))
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| 177 | {
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| 178 | Assert(offFromEnd < cwcNativeTarget);
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| 179 | pwszNativeTarget[cwcNativeTarget - offFromEnd] = 0;
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| 180 | offFromEnd++;
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| 181 | }
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| 182 | }
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| 183 | #endif
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| 184 |
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| 185 | if (enmType == RTSYMLINKTYPE_UNKNOWN)
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| 186 | {
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| 187 | if ( cchTarget > cchVolSpecTarget
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| 188 | && RTPATH_IS_SLASH(pszTarget[cchTarget - 1]))
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| 189 | enmType = RTSYMLINKTYPE_DIR;
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| 190 | else if (cchVolSpecTarget)
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| 191 | {
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| 192 | /** @todo this is subject to sharing violations. */
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| 193 | DWORD dwAttr = GetFileAttributesW(pwszNativeTarget);
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| 194 | if ( dwAttr != INVALID_FILE_ATTRIBUTES
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| 195 | && (dwAttr & FILE_ATTRIBUTE_DIRECTORY))
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| 196 | enmType = RTSYMLINKTYPE_DIR;
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| 197 | }
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| 198 | else
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| 199 | {
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| 200 | /** @todo Join the symlink directory with the target and
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| 201 | * look up the attributes on that. -lazy bird. */
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| 202 | }
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| 203 | }
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| 204 |
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| 205 | /*
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| 206 | * Create the link.
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| 207 | */
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| 208 | if (s_pfnCreateSymbolicLinkW(pwszNativeSymlink, pwszNativeTarget, enmType == RTSYMLINKTYPE_DIR))
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| 209 | rc = VINF_SUCCESS;
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| 210 | else
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| 211 | rc = RTErrConvertFromWin32(GetLastError());
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| 212 |
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| 213 | RTUtf16Free(pwszNativeTarget);
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| 214 | }
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| 215 | RTUtf16Free(pwszNativeSymlink);
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| 216 | }
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| 217 |
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| 218 | LogFlow(("RTSymlinkCreate(%p={%s}, %p={%s}, %d): returns %Rrc\n", pszSymlink, pszSymlink, pszTarget, pszTarget, enmType, rc));
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| 219 | return rc;
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| 220 | }
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| 221 |
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| 222 |
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| 223 | RTDECL(int) RTSymlinkDelete(const char *pszSymlink)
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| 224 | {
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| 225 | /*
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| 226 | * Convert the path.
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| 227 | */
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| 228 | PRTUTF16 pwszNativeSymlink;
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| 229 | int rc = RTStrToUtf16(pszSymlink, &pwszNativeSymlink);
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| 230 | if (RT_SUCCESS(rc))
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| 231 | {
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| 232 | /*
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| 233 | * We have to use different APIs depending on whether this is a
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| 234 | * directory or file link. This means we're subject to one more race
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| 235 | * than on posix at the moment. We could probably avoid this though,
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| 236 | * if we wanted to go talk with the native API layer below Win32...
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| 237 | */
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| 238 | DWORD dwAttr = GetFileAttributesW(pwszNativeSymlink);
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| 239 | if (dwAttr != INVALID_FILE_ATTRIBUTES)
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| 240 | {
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| 241 | if (dwAttr & FILE_ATTRIBUTE_REPARSE_POINT)
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| 242 | {
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| 243 | BOOL fRc;
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| 244 | if (dwAttr & FILE_ATTRIBUTE_DIRECTORY)
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| 245 | fRc = RemoveDirectoryW(pwszNativeSymlink);
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| 246 | else
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| 247 | fRc = DeleteFileW(pwszNativeSymlink);
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| 248 | if (fRc)
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| 249 | rc = VINF_SUCCESS;
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| 250 | else
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| 251 | rc = RTErrConvertFromWin32(GetLastError());
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| 252 | }
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| 253 | else
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| 254 | rc = VERR_NOT_SYMLINK;
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| 255 | }
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| 256 | else
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| 257 | rc = RTErrConvertFromWin32(GetLastError());
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| 258 | RTUtf16Free(pwszNativeSymlink);
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| 259 | }
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| 260 |
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| 261 | LogFlow(("RTSymlinkDelete(%p={%s}): returns %Rrc\n", pszSymlink, pszSymlink, rc));
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| 262 | return rc;
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| 263 | }
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| 264 |
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| 265 |
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| 266 | RTDECL(int) RTSymlinkRead(const char *pszSymlink, char *pszTarget, size_t cbTarget)
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| 267 | {
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| 268 | char *pszMyTarget;
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| 269 | int rc = RTSymlinkReadA(pszSymlink, &pszMyTarget);
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| 270 | if (RT_SUCCESS(rc))
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| 271 | {
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| 272 | rc = RTStrCopy(pszTarget, cbTarget, pszMyTarget);
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| 273 | RTStrFree(pszMyTarget);
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| 274 | }
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| 275 | LogFlow(("RTSymlinkRead(%p={%s}): returns %Rrc\n", pszSymlink, pszSymlink, rc));
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| 276 | return rc;
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| 277 | }
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| 278 |
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| 279 |
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| 280 | RTDECL(int) RTSymlinkReadA(const char *pszSymlink, char **ppszTarget)
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| 281 | {
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| 282 | AssertPtr(ppszTarget);
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| 283 | PRTUTF16 pwszNativeSymlink;
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| 284 | int rc = RTStrToUtf16(pszSymlink, &pwszNativeSymlink);
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| 285 | if (RT_SUCCESS(rc))
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| 286 | {
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| 287 | HANDLE hSymlink = CreateFileW(pwszNativeSymlink,
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| 288 | GENERIC_READ,
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| 289 | FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
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| 290 | NULL,
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| 291 | OPEN_EXISTING,
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| 292 | FILE_FLAG_OPEN_REPARSE_POINT | FILE_FLAG_BACKUP_SEMANTICS,
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| 293 | NULL);
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| 294 | if (hSymlink != INVALID_HANDLE_VALUE)
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| 295 | {
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| 296 | DWORD cbReturned = 0;
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| 297 | union
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| 298 | {
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| 299 | MY_REPARSE_DATA_BUFFER Buf;
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| 300 | uint8_t abBuf[16*_1K + sizeof(WCHAR)];
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| 301 | } u;
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| 302 | if (DeviceIoControl(hSymlink,
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| 303 | MY_FSCTL_GET_REPARSE_POINT,
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| 304 | NULL /*pInBuffer */,
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| 305 | 0 /*cbInBuffer */,
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| 306 | &u.Buf,
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| 307 | sizeof(u) - sizeof(WCHAR),
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| 308 | &cbReturned,
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| 309 | NULL /*pOverlapped*/))
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| 310 | {
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| 311 | if (u.Buf.ReparseTag == MY_IO_REPARSE_TAG_SYMLINK)
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| 312 | {
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| 313 | PWCHAR pwszTarget = &u.Buf.SymbolicLinkReparseBuffer.PathBuffer[0];
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| 314 | pwszTarget += u.Buf.SymbolicLinkReparseBuffer.SubstituteNameOffset / 2;
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| 315 | pwszTarget[u.Buf.SymbolicLinkReparseBuffer.SubstituteNameLength / 2] = 0;
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| 316 | if ( !(u.Buf.SymbolicLinkReparseBuffer.Flags & MY_SYMLINK_FLAG_RELATIVE)
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| 317 | && pwszTarget[0] == '\\'
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| 318 | && pwszTarget[1] == '?'
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| 319 | && pwszTarget[2] == '?'
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| 320 | && pwszTarget[3] == '\\'
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| 321 | && pwszTarget[4] != 0
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| 322 | )
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| 323 | pwszTarget += 4;
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| 324 | rc = RTUtf16ToUtf8(pwszTarget, ppszTarget);
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| 325 | }
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| 326 | else
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| 327 | rc = VERR_NOT_SYMLINK;
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| 328 | }
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| 329 | else
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| 330 | rc = RTErrConvertFromWin32(GetLastError());
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| 331 | CloseHandle(hSymlink);
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| 332 | }
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| 333 | else
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| 334 | rc = RTErrConvertFromWin32(GetLastError());
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| 335 | RTUtf16Free(pwszNativeSymlink);
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| 336 | }
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| 337 |
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| 338 | if (RT_SUCCESS(rc))
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| 339 | LogFlow(("RTSymlinkReadA(%p={%s},%p): returns %Rrc *ppszTarget=%p:{%s}\n", pszSymlink, pszSymlink, ppszTarget, rc, *ppszTarget, *ppszTarget));
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| 340 | else
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| 341 | LogFlow(("RTSymlinkReadA(%p={%s},%p): returns %Rrc\n", pszSymlink, pszSymlink, ppszTarget, rc));
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| 342 | return rc;
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| 343 | }
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| 344 |
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