| 1 | /* $Id: RTDirCreateUniqueNumbered-generic.cpp 82968 2020-02-04 10:35:17Z vboxsync $ */
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| 2 | /** @file
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| 3 | * IPRT - RTDirCreateUniqueNumbered, generic implementation.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2011-2020 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 | #include <iprt/dir.h>
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| 32 | #include "internal/iprt.h"
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| 33 |
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| 34 | #include <iprt/assert.h>
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| 35 | #include <iprt/err.h>
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| 36 | #include <iprt/path.h>
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| 37 | #include <iprt/rand.h>
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| 38 | #include <iprt/string.h>
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| 39 |
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| 40 |
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| 41 | RTDECL(int) RTDirCreateUniqueNumbered(char *pszPath, size_t cbSize, RTFMODE fMode, size_t cchDigits, char chSep)
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| 42 | {
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| 43 | /*
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| 44 | * Validate input.
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| 45 | */
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| 46 | AssertPtrReturn(pszPath, VERR_INVALID_POINTER);
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| 47 | AssertReturn(cbSize, VERR_BUFFER_OVERFLOW);
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| 48 | AssertReturn(cchDigits > 0, VERR_INVALID_PARAMETER);
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| 49 | AssertReturn(cchDigits < 64, VERR_INVALID_PARAMETER);
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| 50 |
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| 51 | /* Check that there is sufficient space. */
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| 52 | char *pszEnd = RTStrEnd(pszPath, cbSize);
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| 53 | AssertReturn(pszEnd, VERR_BUFFER_OVERFLOW);
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| 54 | size_t cbLeft = cbSize - (pszEnd - pszPath);
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| 55 | AssertReturn(cbLeft > (chSep ? 1U : 0U) + cchDigits, VERR_BUFFER_OVERFLOW);
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| 56 |
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| 57 | /*
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| 58 | * First try the pretty name without any numbers appended.
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| 59 | */
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| 60 | int rc = RTDirCreate(pszPath, fMode, 0);
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| 61 | if (RT_SUCCESS(rc))
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| 62 | return rc;
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| 63 | if (rc == VERR_ALREADY_EXISTS)
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| 64 | {
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| 65 | /*
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| 66 | * Already exist, apply template specification.
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| 67 | */
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| 68 |
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| 69 | /* Max 10000 tries (like RTDirCreateTemp), but stop earlier if we haven't got enough digits to work with. */
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| 70 | uint32_t cMaxTries;
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| 71 | switch (cchDigits)
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| 72 | {
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| 73 | case 1: cMaxTries = 40; break;
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| 74 | case 2: cMaxTries = 400; break;
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| 75 | case 3: cMaxTries = 4000; break;
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| 76 | default: cMaxTries = 10000; break;
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| 77 | }
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| 78 |
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| 79 | static uint64_t const s_aEndSeqs[] =
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| 80 | {
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| 81 | UINT64_C(0),
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| 82 | UINT64_C(9),
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| 83 | UINT64_C(99),
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| 84 | UINT64_C(999),
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| 85 | UINT64_C(9999),
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| 86 | UINT64_C(99999),
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| 87 | UINT64_C(999999),
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| 88 | UINT64_C(9999999),
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| 89 | UINT64_C(99999999),
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| 90 | UINT64_C(999999999),
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| 91 | UINT64_C(9999999999),
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| 92 | UINT64_C(99999999999),
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| 93 | UINT64_C(999999999999),
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| 94 | UINT64_C(9999999999999),
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| 95 | UINT64_C(99999999999999),
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| 96 | UINT64_C(999999999999999),
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| 97 | UINT64_C(9999999999999999),
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| 98 | UINT64_C(99999999999999999),
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| 99 | UINT64_C(999999999999999999),
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| 100 | UINT64_C(9999999999999999999),
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| 101 | };
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| 102 | uint64_t const uEndSeq = cchDigits < RT_ELEMENTS(s_aEndSeqs) ? s_aEndSeqs[cchDigits] : UINT64_MAX;
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| 103 |
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| 104 | /* Add separator if requested. */
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| 105 | if (chSep != '\0')
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| 106 | {
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| 107 | *pszEnd++ = chSep;
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| 108 | *pszEnd = '\0';
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| 109 | cbLeft--;
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| 110 | }
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| 111 |
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| 112 | Assert(cbLeft > cchDigits);
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| 113 | for (uint32_t iTry = 0; iTry <= cMaxTries; iTry++)
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| 114 | {
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| 115 | /* Try sequentially first for a little bit, then switch to random numbers. */
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| 116 | uint64_t iSeq;
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| 117 | if (iTry > 20)
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| 118 | iSeq = RTRandU64Ex(0, uEndSeq);
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| 119 | else
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| 120 | {
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| 121 | iSeq = iTry;
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| 122 | if (uEndSeq < UINT64_MAX)
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| 123 | iSeq %= uEndSeq + 1;
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| 124 | }
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| 125 | ssize_t cchRet = RTStrFormatU64(pszEnd, cbLeft, iSeq, 10 /*uiBase*/,
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| 126 | (int)cchDigits /*cchWidth*/, 0 /*cchPrecision*/, RTSTR_F_WIDTH | RTSTR_F_ZEROPAD);
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| 127 | Assert((size_t)cchRet == cchDigits); NOREF(cchRet);
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| 128 |
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| 129 | rc = RTDirCreate(pszPath, fMode, 0);
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| 130 | if (RT_SUCCESS(rc))
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| 131 | return rc;
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| 132 | if (rc != VERR_ALREADY_EXISTS)
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| 133 | break;
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| 134 | }
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| 135 | }
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| 136 |
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| 137 | /* We've given up or failed. */
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| 138 | *pszPath = '\0';
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| 139 | return rc;
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| 140 | }
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| 141 | RT_EXPORT_SYMBOL(RTDirCreateUniqueNumbered);
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| 142 |
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