utils: add a simple elfreader to extract section names

Change-Id: Ia761b8d2150ff2c47a2e26c403a2b00127023d8b
Reviewed-by: hjk <qthjk@ovi.com>

src/libs/utils/elfreader.cpp

+/****************************************************************************
+**
+** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "elfreader.h"
+#include "qtcassert.h"
+
+#include <QFile>
+#include <QLibrary>
+#include <QDebug>
+
+namespace Utils {
+
+template <typename T>
+T read(const char *s, ElfReader::ElfEndian endian)
+{
+    if (endian == ElfReader::ElfBigEndian)
+        return qFromBigEndian<T>(reinterpret_cast<const uchar *>(s));
+    else
+        return qFromLittleEndian<T>(reinterpret_cast<const uchar *>(s));
+}
+
+ElfReader::ElfReader(const QString &binary)
+    : m_binary(binary)
+{
+}
+
+const char *ElfReader::parseSectionHeader(const char *data, ElfSectionHeader *sh)
+{
+    sh->name = read<qelfword_t>(data, m_endian);
+    data += sizeof(qelfword_t); // sh_name
+    sh->type = read<qelfword_t>(data, m_endian);
+    data += sizeof(qelfword_t)  // sh_type
+         + sizeof(qelfaddr_t)   // sh_flags
+         + sizeof(qelfaddr_t);  // sh_addr
+    sh->offset = read<qelfoff_t>(data, m_endian);
+    data += sizeof(qelfoff_t);  // sh_offset
+    sh->size = read<qelfoff_t>(data, m_endian);
+    data += sizeof(qelfoff_t);  // sh_size
+    return data;
+}
+
+ElfReader::Result ElfReader::parse(const char *dataStart, quint64 fdlen,
+    QList<QByteArray> *sectionNames)
+{
+    if (fdlen < 64) {
+        m_errorString = QLibrary::tr("'%1' is not an ELF object (%2)")
+            .arg(m_binary).arg(QLatin1String("file too small"));
+        return NotElf;
+    }
+    const char *data = dataStart;
+    if (strncmp(data, "\177ELF", 4) != 0) {
+        m_errorString = QLibrary::tr("'%1' is not an ELF object")
+                .arg(m_binary);
+        return NotElf;
+    }
+
+    // 32 or 64 bit
+    if (data[4] != 1 && data[4] != 2) {
+        m_errorString = QLibrary::tr("'%1' is an invalid ELF object (%2)")
+            .arg(m_binary).arg(QLatin1String("odd cpu architecture"));
+        return Corrupt;
+    }
+
+    // int bits = (data[4] << 5);
+    // If you remove this check to read ELF objects of a different arch,
+    // please make sure you modify the typedefs
+    // to match the _plugin_ architecture.
+    // if ((sizeof(void*) == 4 && bits != 32)
+    //     || (sizeof(void*) == 8 && bits != 64)) {
+    //     if (errorString)
+    //         *errorString = QLibrary::tr("'%1' is an invalid ELF object (%2)")
+    //         .arg(m_binary).arg(QLatin1String("wrong cpu architecture"));
+    //     return Corrupt;
+    // }
+
+    // Read Endianess.
+    if (data[5] == 0) {
+        m_errorString = QLibrary::tr("'%1' is an invalid ELF object (%2)")
+            .arg(m_binary).arg(QLatin1String("odd endianess"));
+        return Corrupt;
+    }
+    m_endian = (data[5] == 1 ? ElfLittleEndian : ElfBigEndian);
+
+    data += 16                  // e_ident
+         +  sizeof(qelfhalf_t)  // e_type
+         +  sizeof(qelfhalf_t)  // e_machine
+         +  sizeof(qelfword_t)  // e_version
+         +  sizeof(qelfaddr_t)  // e_entry
+         +  sizeof(qelfoff_t);  // e_phoff
+
+    qelfoff_t e_shoff = read<qelfoff_t>(data, m_endian);
+    data += sizeof(qelfoff_t)    // e_shoff
+         +  sizeof(qelfword_t);  // e_flags
+
+    qelfhalf_t e_shsize = read<qelfhalf_t>(data, m_endian);
+
+    if (e_shsize > fdlen) {
+        m_errorString = QLibrary::tr("'%1' is an invalid ELF object (%2)")
+            .arg(m_binary).arg(QLatin1String("unexpected e_shsize"));
+        return Corrupt;
+    }
+
+    data += sizeof(qelfhalf_t)  // e_ehsize
+         +  sizeof(qelfhalf_t)  // e_phentsize
+         +  sizeof(qelfhalf_t); // e_phnum
+
+    qelfhalf_t e_shentsize = read<qelfhalf_t>(data, m_endian);
+
+    if (e_shentsize % 4) {
+        m_errorString = QLibrary::tr("'%1' is an invalid ELF object (%2)")
+            .arg(m_binary).arg(QLatin1String("unexpected e_shentsize"));
+        return Corrupt;
+    }
+    data += sizeof(qelfhalf_t); // e_shentsize
+    qelfhalf_t e_shnum     = read<qelfhalf_t>(data, m_endian);
+    data += sizeof(qelfhalf_t); // e_shnum
+    qelfhalf_t e_shtrndx   = read<qelfhalf_t>(data, m_endian);
+    data += sizeof(qelfhalf_t); // e_shtrndx
+
+    if (quint32(e_shnum * e_shentsize) > fdlen) {
+        m_errorString = QLibrary::tr("'%1' is an invalid ELF object (%2)")
+            .arg(m_binary)
+            .arg(QLatin1String("announced %2 sections, each %3 bytes, exceed file size"))
+            .arg(e_shnum).arg(e_shentsize);
+        return Corrupt;
+    }
+
+    ElfSectionHeader strtab;
+    qulonglong soff = e_shoff + e_shentsize * (e_shtrndx);
+
+    if ((soff + e_shentsize) > fdlen || soff % 4 || soff == 0) {
+        m_errorString = QLibrary::tr("'%1' is an invalid ELF object (%2)")
+           .arg(m_binary)
+           .arg(QLatin1String("shstrtab section header seems to be at %1"))
+           .arg(QString::number(soff, 16));
+        return Corrupt;
+    }
+
+    parseSectionHeader(dataStart + soff, &strtab);
+    const int stringTableFileOffset = strtab.offset;
+
+    if (quint32(stringTableFileOffset + e_shentsize) >= fdlen
+            || stringTableFileOffset == 0) {
+        m_errorString = QLibrary::tr("'%1' is an invalid ELF object (%2)")
+            .arg(m_binary)
+            .arg(QLatin1String("string table seems to be at %1"))
+            .arg(QString::number(soff, 16));
+        return Corrupt;
+    }
+
+    const char *s = dataStart + e_shoff;
+    for (int i = 0; i < e_shnum; ++i) {
+        ElfSectionHeader sh;
+        parseSectionHeader(s, &sh);
+        if (sh.name == 0) {
+            s += e_shentsize;
+            continue;
+        }
+        const char *shnam = dataStart + stringTableFileOffset + sh.name;
+
+        if (stringTableFileOffset + sh.name > fdlen) {
+            m_errorString = QLibrary::tr("'%1' is an invalid ELF object (%2)")
+                .arg(m_binary)
+                .arg(QLatin1String("section name %2 of %3 behind end of file"))
+                .arg(i).arg(e_shnum);
+            return Corrupt;
+        }
+
+        if (sectionNames)
+            sectionNames->append(shnam);
+
+        s += e_shentsize;
+    }
+    return Ok;
+}
+
+QList<QByteArray> ElfReader::sectionNames()
+{
+    QList<QByteArray> names;
+
+    QFile file(m_binary);
+    if (!file.open(QIODevice::ReadOnly)) {
+        m_errorString = file.errorString();
+        return names;
+    }
+
+    QByteArray data;
+    const char *filedata = 0;
+    quint64 fdlen = file.size();
+    filedata = (char *) file.map(0, fdlen);
+    if (filedata == 0) {
+        // Try reading the data into memory instead.
+        data = file.readAll();
+        filedata = data.constData();
+        fdlen = data.size();
+    }
+
+    parse(filedata, fdlen, &names);
+    return names;
+}
+
+} // namespace Utils

src/libs/utils/elfreader.h

+/****************************************************************************
+**
+** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+// This is essentially copied from Qt 5's
+// qtbase/src/corelib/plugin/qelfparser_p.{h,cpp}
+
+#ifndef UTILS_ELFREADER_H
+#define UTILS_ELFREADER_H
+
+#include "utils_global.h"
+
+#include <qendian.h>
+#include <qstring.h>
+
+namespace Utils {
+
+typedef quint16  qelfhalf_t;
+typedef quint32  qelfword_t;
+typedef quintptr qelfoff_t;
+typedef quintptr qelfaddr_t;
+
+class QTCREATOR_UTILS_EXPORT ElfReader
+{
+public:
+    explicit ElfReader(const QString &binary);
+
+    struct ElfSectionHeader
+    {
+        qelfword_t name;
+        qelfword_t type;
+        qelfoff_t  offset;
+        qelfoff_t  size;
+    };
+
+    enum ElfEndian { ElfLittleEndian = 0, ElfBigEndian = 1 };
+    QList<QByteArray> sectionNames();
+    QString errorString() const { return m_errorString; }
+
+private:
+    enum Result { Ok, NotElf, Corrupt };
+
+    const char *parseSectionHeader(const char *s, ElfSectionHeader *sh);
+    Result parse(const char *dataStart, quint64 fdlen, QList<QByteArray> *sectionNames);
+
+    QString m_binary;
+    QString m_errorString;
+    ElfEndian m_endian;
+};
+
+} // namespace Utils
+
+#endif // UTILS_ELFREADER_H

src/libs/utils/utils-lib.pri

@@ -77,7 +77,8 @@ SOURCES += $$PWD/environment.cpp \
     $$PWD/tcpportsgatherer.cpp \
     $$PWD/appmainwindow.cpp \
     $$PWD/basetreeview.cpp \
-    $$PWD/qtcassert.cpp
+    $$PWD/qtcassert.cpp \
+    $$PWD/elfreader.cpp
 
 win32 {
     SOURCES += \
@@ -161,7 +162,8 @@ HEADERS += \
     $$PWD/portlist.h \
     $$PWD/tcpportsgatherer.h \
     $$PWD/appmainwindow.h \
-    $$PWD/basetreeview.h
+    $$PWD/basetreeview.h \
+    $$PWD/elfreader.h
 
 FORMS += $$PWD/filewizardpage.ui \
     $$PWD/projectintropage.ui \

src/libs/utils/utils.qbs

@@ -51,6 +51,8 @@ QtcLibrary {
         "detailsbutton.h",
         "detailswidget.cpp",
         "detailswidget.h",
+        "elfreader.cpp",
+        "elfreader.h",
         "environment.h",
         "environmentmodel.cpp",
         "environmentmodel.h",