[33426] | 1 | /* $Id: symlink-posix.cpp 98103 2023-01-17 14:15:46Z vboxsync $ */
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| 2 | /** @file
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| 3 | * IPRT - Symbolic Links, POSIX.
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| 4 | */
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| 5 |
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| 6 | /*
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[98103] | 7 | * Copyright (C) 2010-2023 Oracle and/or its affiliates.
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[33426] | 8 | *
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[96407] | 9 | * This file is part of VirtualBox base platform packages, as
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| 10 | * available from https://www.virtualbox.org.
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[33426] | 11 | *
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[96407] | 12 | * This program is free software; you can redistribute it and/or
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| 13 | * modify it under the terms of the GNU General Public License
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| 14 | * as published by the Free Software Foundation, in version 3 of the
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| 15 | * License.
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| 16 | *
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| 17 | * This program is distributed in the hope that it will be useful, but
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| 18 | * WITHOUT ANY WARRANTY; without even the implied warranty of
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| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 20 | * General Public License for more details.
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| 21 | *
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| 22 | * You should have received a copy of the GNU General Public License
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| 23 | * along with this program; if not, see <https://www.gnu.org/licenses>.
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| 24 | *
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[33426] | 25 | * The contents of this file may alternatively be used under the terms
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| 26 | * of the Common Development and Distribution License Version 1.0
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[96407] | 27 | * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
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| 28 | * in the VirtualBox distribution, in which case the provisions of the
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[33426] | 29 | * CDDL are applicable instead of those of the GPL.
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| 30 | *
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| 31 | * You may elect to license modified versions of this file under the
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| 32 | * terms and conditions of either the GPL or the CDDL or both.
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[96407] | 33 | *
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| 34 | * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
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[33426] | 35 | */
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| 36 |
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| 37 |
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[57358] | 38 | /*********************************************************************************************************************************
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| 39 | * Header Files *
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| 40 | *********************************************************************************************************************************/
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[33426] | 41 | #define LOG_GROUP RTLOGGROUP_SYMLINK
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| 42 |
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| 43 | #include <errno.h>
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| 44 | #include <sys/stat.h>
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| 45 | #include <unistd.h>
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| 46 |
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| 47 | #include <iprt/symlink.h>
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| 48 |
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| 49 | #include <iprt/assert.h>
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| 50 | #include <iprt/err.h>
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| 51 | #include <iprt/log.h>
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| 52 | #include <iprt/mem.h>
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| 53 | #include <iprt/string.h>
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| 54 | #include "internal/path.h"
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| 55 |
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| 56 |
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| 57 |
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| 58 | RTDECL(bool) RTSymlinkExists(const char *pszSymlink)
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| 59 | {
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| 60 | bool fRc = false;
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| 61 | char const *pszNativeSymlink;
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| 62 | int rc = rtPathToNative(&pszNativeSymlink, pszSymlink, NULL);
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| 63 | if (RT_SUCCESS(rc))
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| 64 | {
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| 65 | struct stat s;
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| 66 | fRc = !lstat(pszNativeSymlink, &s)
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| 67 | && S_ISLNK(s.st_mode);
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| 68 |
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| 69 | rtPathFreeNative(pszNativeSymlink, pszSymlink);
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| 70 | }
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| 71 |
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| 72 | LogFlow(("RTSymlinkExists(%p={%s}): returns %RTbool\n", pszSymlink, pszSymlink, fRc));
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| 73 | return fRc;
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| 74 | }
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| 75 |
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| 76 |
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| 77 | RTDECL(bool) RTSymlinkIsDangling(const char *pszSymlink)
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| 78 | {
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| 79 | bool fRc = false;
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| 80 | char const *pszNativeSymlink;
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| 81 | int rc = rtPathToNative(&pszNativeSymlink, pszSymlink, NULL);
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| 82 | if (RT_SUCCESS(rc))
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| 83 | {
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| 84 | struct stat s;
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| 85 | fRc = !lstat(pszNativeSymlink, &s)
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| 86 | && S_ISLNK(s.st_mode);
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| 87 | if (fRc)
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| 88 | {
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| 89 | errno = 0;
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| 90 | fRc = stat(pszNativeSymlink, &s) != 0
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| 91 | && ( errno == ENOENT
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| 92 | || errno == ENOTDIR
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| 93 | || errno == ELOOP);
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| 94 | }
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| 95 |
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| 96 | rtPathFreeNative(pszNativeSymlink, pszSymlink);
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| 97 | }
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| 98 |
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| 99 | LogFlow(("RTSymlinkIsDangling(%p={%s}): returns %RTbool\n", pszSymlink, pszSymlink, fRc));
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| 100 | return fRc;
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| 101 | }
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| 102 |
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| 103 |
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[39612] | 104 | RTDECL(int) RTSymlinkCreate(const char *pszSymlink, const char *pszTarget, RTSYMLINKTYPE enmType, uint32_t fCreate)
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[33426] | 105 | {
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[62564] | 106 | RT_NOREF_PV(fCreate);
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| 107 |
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[33426] | 108 | /*
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| 109 | * Validate the input.
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| 110 | */
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| 111 | AssertReturn(enmType > RTSYMLINKTYPE_INVALID && enmType < RTSYMLINKTYPE_END, VERR_INVALID_PARAMETER);
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| 112 | AssertPtrReturn(pszSymlink, VERR_INVALID_POINTER);
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| 113 | AssertPtrReturn(pszTarget, VERR_INVALID_POINTER);
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| 114 |
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| 115 | /*
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| 116 | * Convert the paths.
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| 117 | */
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| 118 | char const *pszNativeSymlink;
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| 119 | int rc = rtPathToNative(&pszNativeSymlink, pszSymlink, NULL);
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| 120 | if (RT_SUCCESS(rc))
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| 121 | {
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| 122 | const char *pszNativeTarget;
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| 123 | rc = rtPathToNative(&pszNativeTarget, pszTarget, NULL);
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| 124 | if (RT_SUCCESS(rc))
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| 125 | {
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| 126 | /*
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| 127 | * Create the link.
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| 128 | */
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| 129 | if (symlink(pszNativeTarget, pszNativeSymlink) == 0)
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| 130 | rc = VINF_SUCCESS;
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| 131 | else
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| 132 | rc = RTErrConvertFromErrno(errno);
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| 133 |
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| 134 | rtPathFreeNative(pszNativeTarget, pszTarget);
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| 135 | }
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| 136 | rtPathFreeNative(pszNativeSymlink, pszSymlink);
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| 137 | }
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| 138 |
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[39612] | 139 | LogFlow(("RTSymlinkCreate(%p={%s}, %p={%s}, %d, %#x): returns %Rrc\n", pszSymlink, pszSymlink, pszTarget, pszTarget, enmType, fCreate, rc));
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[33426] | 140 | return rc;
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| 141 | }
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| 142 |
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| 143 |
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[39612] | 144 | RTDECL(int) RTSymlinkDelete(const char *pszSymlink, uint32_t fDelete)
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[33426] | 145 | {
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[62564] | 146 | RT_NOREF_PV(fDelete);
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| 147 |
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[33426] | 148 | char const *pszNativeSymlink;
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| 149 | int rc = rtPathToNative(&pszNativeSymlink, pszSymlink, NULL);
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| 150 | if (RT_SUCCESS(rc))
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| 151 | {
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| 152 | struct stat s;
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| 153 | if (!lstat(pszNativeSymlink, &s))
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| 154 | {
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| 155 | if (S_ISLNK(s.st_mode))
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| 156 | {
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| 157 | if (unlink(pszNativeSymlink) == 0)
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| 158 | rc = VINF_SUCCESS;
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| 159 | else
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| 160 | rc = RTErrConvertFromErrno(errno);
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| 161 | }
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| 162 | else
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| 163 | rc = VERR_NOT_SYMLINK;
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| 164 | }
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| 165 | else
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| 166 | rc = RTErrConvertFromErrno(errno);
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| 167 | rtPathFreeNative(pszNativeSymlink, pszSymlink);
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| 168 | }
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| 169 |
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[39612] | 170 | LogFlow(("RTSymlinkDelete(%p={%s}, #%x): returns %Rrc\n", pszSymlink, pszSymlink, fDelete, rc));
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[33426] | 171 | return rc;
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| 172 | }
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| 173 |
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| 174 |
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[39612] | 175 | RTDECL(int) RTSymlinkRead(const char *pszSymlink, char *pszTarget, size_t cbTarget, uint32_t fRead)
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[33426] | 176 | {
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[62564] | 177 | RT_NOREF_PV(fRead);
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| 178 |
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[33426] | 179 | char *pszMyTarget;
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| 180 | int rc = RTSymlinkReadA(pszSymlink, &pszMyTarget);
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| 181 | if (RT_SUCCESS(rc))
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| 182 | {
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| 183 | rc = RTStrCopy(pszTarget, cbTarget, pszMyTarget);
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| 184 | RTStrFree(pszMyTarget);
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| 185 | }
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| 186 | LogFlow(("RTSymlinkRead(%p={%s}): returns %Rrc\n", pszSymlink, pszSymlink, rc));
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| 187 | return rc;
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| 188 | }
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| 189 |
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| 190 |
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| 191 | RTDECL(int) RTSymlinkReadA(const char *pszSymlink, char **ppszTarget)
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| 192 | {
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| 193 | AssertPtr(ppszTarget);
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| 194 | char const *pszNativeSymlink;
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| 195 | int rc = rtPathToNative(&pszNativeSymlink, pszSymlink, NULL);
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| 196 | if (RT_SUCCESS(rc))
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| 197 | {
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| 198 | /* Guess the initial buffer size. */
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| 199 | ssize_t cbBuf;
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| 200 | struct stat s;
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| 201 | if (!lstat(pszNativeSymlink, &s))
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[60371] | 202 | cbBuf = RT_MAX(RT_ALIGN_Z(s.st_size, 64), 64);
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[33426] | 203 | else
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| 204 | cbBuf = 1024;
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| 205 |
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| 206 | /* Read loop that grows the buffer. */
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| 207 | char *pszBuf = NULL;
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| 208 | for (;;)
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| 209 | {
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| 210 | RTMemTmpFree(pszBuf);
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| 211 | pszBuf = (char *)RTMemTmpAlloc(cbBuf);
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| 212 | if (pszBuf)
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| 213 | {
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| 214 | ssize_t cbReturned = readlink(pszNativeSymlink, pszBuf, cbBuf);
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| 215 | if (cbReturned >= cbBuf)
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| 216 | {
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| 217 | /* Increase the buffer size and try again */
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| 218 | cbBuf *= 2;
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| 219 | continue;
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| 220 | }
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| 221 |
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| 222 | if (cbReturned > 0)
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| 223 | {
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| 224 | pszBuf[cbReturned] = '\0';
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| 225 | rc = rtPathFromNativeDup(ppszTarget, pszBuf, pszSymlink);
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| 226 | }
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| 227 | else if (errno == EINVAL)
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| 228 | rc = VERR_NOT_SYMLINK;
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| 229 | else
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| 230 | rc = RTErrConvertFromErrno(errno);
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| 231 | }
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| 232 | else
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| 233 | rc = VERR_NO_TMP_MEMORY;
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| 234 | break;
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| 235 | } /* for loop */
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| 236 |
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| 237 | RTMemTmpFree(pszBuf);
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| 238 | rtPathFreeNative(pszNativeSymlink, pszSymlink);
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| 239 | }
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| 240 |
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| 241 | if (RT_SUCCESS(rc))
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| 242 | LogFlow(("RTSymlinkReadA(%p={%s},%p): returns %Rrc *ppszTarget=%p:{%s}\n", pszSymlink, pszSymlink, ppszTarget, rc, *ppszTarget, *ppszTarget));
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| 243 | else
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| 244 | LogFlow(("RTSymlinkReadA(%p={%s},%p): returns %Rrc\n", pszSymlink, pszSymlink, ppszTarget, rc));
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| 245 | return rc;
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| 246 | }
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| 247 |
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