| 1 | /* $Id: filelock-os2.cpp 82968 2020-02-04 10:35:17Z vboxsync $ */
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| 2 | /** @file
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| 3 | * IPRT - File Locking, OS/2.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2008-2020 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_FILE
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| 32 |
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| 33 | #include <errno.h>
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| 34 | #include <sys/types.h>
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| 35 | #include <sys/ioctl.h>
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| 36 | #include <sys/fcntl.h>
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| 37 | #include <fcntl.h>
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| 38 | #include <unistd.h>
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| 39 | #include <sys/time.h>
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| 40 |
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| 41 | #include <iprt/file.h>
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| 42 | #include <iprt/assert.h>
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| 43 | #include <iprt/string.h>
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| 44 | #include <iprt/err.h>
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| 45 | #include <iprt/log.h>
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| 46 | #include "internal/file.h"
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| 47 | #include "internal/fs.h"
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| 48 |
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| 49 |
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| 50 |
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| 51 |
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| 52 | RTR3DECL(int) RTFileLock(RTFILE File, unsigned fLock, int64_t offLock, uint64_t cbLock)
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| 53 | {
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| 54 | Assert(offLock >= 0);
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| 55 |
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| 56 | /* Check arguments. */
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| 57 | if (fLock & ~RTFILE_LOCK_MASK)
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| 58 | {
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| 59 | AssertMsgFailed(("Invalid fLock=%08X\n", fLock));
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| 60 | return VERR_INVALID_PARAMETER;
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| 61 | }
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| 62 |
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| 63 | /*
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| 64 | * Validate offset.
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| 65 | */
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| 66 | if ( sizeof(off_t) < sizeof(cbLock)
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| 67 | && ( (offLock >> 32) != 0
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| 68 | || (cbLock >> 32) != 0
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| 69 | || ((offLock + cbLock) >> 32) != 0))
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| 70 | {
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| 71 | AssertMsgFailed(("64-bit file i/o not supported! offLock=%lld cbLock=%lld\n", offLock, cbLock));
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| 72 | return VERR_NOT_SUPPORTED;
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| 73 | }
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| 74 |
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| 75 | /* Prepare flock structure. */
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| 76 | struct flock fl;
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| 77 | Assert(RTFILE_LOCK_WRITE);
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| 78 | fl.l_type = (fLock & RTFILE_LOCK_WRITE) ? F_WRLCK : F_RDLCK;
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| 79 | fl.l_whence = SEEK_SET;
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| 80 | fl.l_start = (off_t)offLock;
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| 81 | fl.l_len = (off_t)cbLock;
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| 82 | fl.l_pid = 0;
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| 83 |
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| 84 | Assert(RTFILE_LOCK_WAIT);
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| 85 | if (fcntl(RTFileToNative(File), (fLock & RTFILE_LOCK_WAIT) ? F_SETLKW : F_SETLK, &fl) >= 0)
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| 86 | return VINF_SUCCESS;
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| 87 |
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| 88 | int iErr = errno;
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| 89 | if ( iErr == EAGAIN
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| 90 | || iErr == EACCES)
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| 91 | return VERR_FILE_LOCK_VIOLATION;
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| 92 |
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| 93 | return RTErrConvertFromErrno(iErr);
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| 94 | }
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| 95 |
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| 96 |
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| 97 | RTR3DECL(int) RTFileChangeLock(RTFILE File, unsigned fLock, int64_t offLock, uint64_t cbLock)
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| 98 | {
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| 99 | /** @todo copied from ../win/fileio-win.cpp for now but a proper solution
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| 100 | * would probably be to modify kLIBC so that __fcntl_locking() first
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| 101 | * assumes a change lock request is made (e.g. the same region was
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| 102 | * previously F_RDLCK'ed and now needs to be F_WRLCK'ed or vice versa) and
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| 103 | * tries to use atomic locking, and only if it fails, it does the regular
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| 104 | * lock procedure. The alternative is to use DosSetFileLocks directly here
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| 105 | * which basically means copy-pasting the __fcntl_locking() source
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| 106 | * code :) Note that the first attempt to call RTFileLock() below assumes
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| 107 | * that kLIBC is patched as described above one day and gives it a chance;
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| 108 | * on failure, we fall back to the Win-like unlock-then-lock approach. */
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| 109 |
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| 110 | int rc = RTFileLock(File, fLock, offLock, cbLock);
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| 111 | if (RT_FAILURE(rc) && rc != VERR_FILE_LOCK_VIOLATION)
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| 112 | return rc;
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| 113 |
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| 114 | /* Check arguments. */
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| 115 | if (fLock & ~RTFILE_LOCK_MASK)
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| 116 | {
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| 117 | AssertMsgFailed(("Invalid fLock=%08X\n", fLock));
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| 118 | return VERR_INVALID_PARAMETER;
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| 119 | }
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| 120 |
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| 121 | /* Remove old lock. */
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| 122 | rc = RTFileUnlock(File, offLock, cbLock);
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| 123 | if (RT_FAILURE(rc))
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| 124 | return rc;
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| 125 |
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| 126 | /* Set new lock. */
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| 127 | rc = RTFileLock(File, fLock, offLock, cbLock);
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| 128 | if (RT_SUCCESS(rc))
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| 129 | return rc;
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| 130 |
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| 131 | /* Try to restore old lock. */
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| 132 | unsigned fLockOld = (fLock & RTFILE_LOCK_WRITE) ? fLock & ~RTFILE_LOCK_WRITE : fLock | RTFILE_LOCK_WRITE;
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| 133 | rc = RTFileLock(File, fLockOld, offLock, cbLock);
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| 134 | if (RT_SUCCESS(rc))
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| 135 | return VERR_FILE_LOCK_VIOLATION;
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| 136 | else
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| 137 | return VERR_FILE_LOCK_LOST;
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| 138 | }
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| 139 |
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| 140 |
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| 141 | RTR3DECL(int) RTFileUnlock(RTFILE File, int64_t offLock, uint64_t cbLock)
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| 142 | {
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| 143 | Assert(offLock >= 0);
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| 144 |
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| 145 | /*
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| 146 | * Validate offset.
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| 147 | */
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| 148 | if ( sizeof(off_t) < sizeof(cbLock)
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| 149 | && ( (offLock >> 32) != 0
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| 150 | || (cbLock >> 32) != 0
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| 151 | || ((offLock + cbLock) >> 32) != 0))
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| 152 | {
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| 153 | AssertMsgFailed(("64-bit file i/o not supported! offLock=%lld cbLock=%lld\n", offLock, cbLock));
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| 154 | return VERR_NOT_SUPPORTED;
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| 155 | }
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| 156 |
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| 157 | /* Prepare flock structure. */
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| 158 | struct flock fl;
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| 159 | fl.l_type = F_UNLCK;
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| 160 | fl.l_whence = SEEK_SET;
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| 161 | fl.l_start = (off_t)offLock;
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| 162 | fl.l_len = (off_t)cbLock;
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| 163 | fl.l_pid = 0;
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| 164 |
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| 165 | if (fcntl(RTFileToNative(File), F_SETLK, &fl) >= 0)
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| 166 | return VINF_SUCCESS;
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| 167 |
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| 168 | /** @todo check error codes for non existing lock. */
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| 169 | int iErr = errno;
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| 170 | if ( iErr == EAGAIN
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| 171 | || iErr == EACCES)
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| 172 | return VERR_FILE_LOCK_VIOLATION;
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| 173 |
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| 174 | return RTErrConvertFromErrno(iErr);
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| 175 | }
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| 176 |
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