| 1 | /* $Id: sysfs.h 14711 2008-11-27 15:16:52Z vboxsync $ */
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| 2 | /** @file
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| 3 | * sysfs.h - convenience routines for getting values from sysfs on Linux.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2008 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 | #ifndef ___VBox_sysfs_h
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| 32 | #define ___VBox_sysfs_h
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| 33 |
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| 34 | #include <iprt/mem.h>
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| 35 | #include <iprt/stream.h>
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| 36 | #include <iprt/string.h>
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| 37 |
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| 38 | __BEGIN_DECLS
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| 39 |
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| 40 | /**
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| 41 | * Read a string value from a sysfs file.
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| 42 | * @returns iprt status value.
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| 43 | * @returns VERR_BUFFER_OVERFLOW if @a cbBuffer was not sufficient to hold the
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| 44 | * value.
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| 45 | * @param pszSysfsPath Path to the sysfs directory to be read from.
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| 46 | * @param pszFile Name of the file in @a pszSysfsPath to read the value
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| 47 | * from.
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| 48 | * @param pszBuffer Where to write the data read.
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| 49 | * @param cbBuffer The size of the buffer in @pszbuffer.
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| 50 | * @param pcbBufActual On success, the size of the data written. On buffer
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| 51 | * overflow the size of the buffer needed. Optional.
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| 52 | */
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| 53 | inline int VBoxSysfsGetString(const char *pszSysfsPath, const char *pszFile,
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| 54 | char *pszBuffer, size_t cbBuffer,
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| 55 | size_t *pcbBufActual)
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| 56 | {
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| 57 | PRTSTREAM pStream;
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| 58 | size_t cbBufActual;
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| 59 | int rc = VINF_SUCCESS;
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| 60 |
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| 61 | char *pszFullName = NULL;
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| 62 | RTMemAutoPtr<char, RTStrFree> FullName;
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| 63 | RTStrAPrintf(&pszFullName, "%s/%s", pszSysfsPath, pszFile);
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| 64 | FullName = pszFullName;
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| 65 | if (!FullName)
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| 66 | rc = VERR_NO_MEMORY;
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| 67 | if (RT_SUCCESS(rc))
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| 68 | rc = RTStrmOpen(pszFullName, "r", &pStream);
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| 69 | if (RT_SUCCESS(rc))
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| 70 | rc = RTStrmReadEx(pStream, pszBuffer, cbBuffer, &cbBufActual);
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| 71 | /* Remove trailing newlines and zero-terminate */
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| 72 | for (size_t i = 0; RT_SUCCESS(rc) && i < cbBufActual; ++i)
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| 73 | if (pszBuffer[i] == '\n')
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| 74 | cbBufActual = i;
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| 75 | if (RT_SUCCESS(rc))
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| 76 | {
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| 77 | if (cbBufActual + 1 > cbBuffer) /* +1 for the '\0' */
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| 78 | rc = VERR_BUFFER_OVERFLOW;
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| 79 | else
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| 80 | pszBuffer[cbBufActual] = '\0';
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| 81 | }
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| 82 | if (pcbBufActual != NULL && (RT_SUCCESS(rc) || rc == VERR_BUFFER_OVERFLOW))
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| 83 | *pcbBufActual = cbBufActual + 1; /* +1 for the '\0' */
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| 84 | RTStrmClose(pStream);
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| 85 | return rc;
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| 86 | }
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| 87 |
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| 88 | /**
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| 89 | * Read a uint32 value from a sysfs file.
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| 90 | * @returns iprt status value.
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| 91 | * See also return codes from RTStrToUInt32Full().
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| 92 | * @param pszSysfsPath Path to the sysfs directory to be read from.
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| 93 | * @param pszFile Name of the file in @a pszSysfsPath to read the value
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| 94 | * from.
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| 95 | * @paramm uBase The base of the representation used.
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| 96 | * If this is zero, the function will look for known
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| 97 | * prefixes before defaulting to 10.
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| 98 | * @param pu32Value Where to store the value read.
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| 99 | */
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| 100 | inline int VBoxSysfsGetUInt32(const char *pszSysfsPath, const char *pszFile,
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| 101 | unsigned uBase, uint32_t *pu32Value)
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| 102 | {
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| 103 | char szBuffer[256];
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| 104 | int rc = VBoxSysfsGetString(pszSysfsPath, pszFile, szBuffer,
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| 105 | sizeof(szBuffer), NULL);
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| 106 | if (RT_SUCCESS(rc))
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| 107 | rc = RTStrToUInt32Full(szBuffer, uBase, pu32Value);
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| 108 | return rc;
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| 109 | }
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| 110 |
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| 111 | __END_DECLS
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| 112 |
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| 113 | #endif
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| 114 |
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