src/corelib/plugin/qlibrary.cpp

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/****************************************************************************
**
** Copyright (C) 1992-2006 Trolltech ASA. All rights reserved.
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** This file may be used under the terms of the GNU General Public
** License version 2.0 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 GNU
** General Public Licensing requirements will be met:
** http://www.trolltech.com/products/qt/opensource.html
**
** If you are unsure which license is appropriate for your use, please
** review the following information:
** http://www.trolltech.com/products/qt/licensing.html or contact the
** sales department at sales@trolltech.com.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
****************************************************************************/

#include "qplatformdefs.h"
#include "qlibrary.h"

#ifndef QT_NO_LIBRARY

#include "qlibrary_p.h"
#include <qstringlist.h>
#include <qfile.h>
#include <qfileinfo.h>
#include <qmutex.h>
#include <qmap.h>
#include <qsettings.h>
#include <qdatetime.h>
#ifdef Q_OS_MAC
#  include <private/qcore_mac_p.h>
#endif
#ifndef NO_ERRNO_H
#include <errno.h>
#endif // NO_ERROR_H
#include <qdebug.h>
#include <qvector.h>

//#define QT_DEBUG_COMPONENT

#ifdef QT_NO_DEBUG
#  define QLIBRARY_AS_DEBUG false
#else
#  define QLIBRARY_AS_DEBUG true
#endif

#if defined(Q_OS_UNIX) && !defined(Q_OS_MAC)
// We don't use separate debug and release libs on UNIX, so we want
// to allow loading plugins, regardless of how they were built.
#  define QT_NO_DEBUG_PLUGIN_CHECK
#endif

Q_GLOBAL_STATIC(QMutex, qt_library_mutex)


struct qt_token_info
{
    qt_token_info(const char *f, const ulong fc)
        : fields(f), field_count(fc), results(fc), lengths(fc)
    {
        results.fill(0);
        lengths.fill(0);
    }

    const char *fields;
    const ulong field_count;

    QVector<const char *> results;
    QVector<ulong> lengths;
};

/*
  return values:
       1 parse ok
       0 eos
      -1 parse error
*/
static int qt_tokenize(const char *s, ulong s_len, ulong *advance,
                        qt_token_info &token_info)
{
    ulong pos = 0, field = 0, fieldlen = 0;
    char current;
    int ret = -1;
    *advance = 0;
    for (;;) {
        current = s[pos];

        // next char
        ++pos;
        ++fieldlen;
        ++*advance;

        if (! current || pos == s_len + 1) {
            // save result
            token_info.results[(int)field] = s;
            token_info.lengths[(int)field] = fieldlen - 1;

            // end of string
            ret = 0;
            break;
        }

        if (current == token_info.fields[field]) {
            // save result
            token_info.results[(int)field] = s;
            token_info.lengths[(int)field] = fieldlen - 1;

            // end of field
            fieldlen = 0;
            ++field;
            if (field == token_info.field_count - 1) {
                // parse ok
                ret = 1;
            }
            if (field == token_info.field_count) {
                // done parsing
                break;
            }

            // reset string and its length
            s = s + pos;
            s_len -= pos;
            pos = 0;
        }
    }

    return ret;
}

/*
  returns true if the string s was correctly parsed, false otherwise.
*/
static bool qt_parse_pattern(const char *s, uint *version, bool *debug, QByteArray *key)
{
    bool ret = true;

    qt_token_info pinfo("=\n", 2);
    int parse;
    ulong at = 0, advance, parselen = qstrlen(s);
    do {
        parse = qt_tokenize(s + at, parselen, &advance, pinfo);
        if (parse == -1) {
            ret = false;
            break;
        }

        at += advance;
        parselen -= advance;

        if (qstrncmp("version", pinfo.results[0], pinfo.lengths[0]) == 0) {
            // parse version string
            qt_token_info pinfo2("..-", 3);
            if (qt_tokenize(pinfo.results[1], pinfo.lengths[1],
                              &advance, pinfo2) != -1) {
                QByteArray m(pinfo2.results[0], pinfo2.lengths[0]);
                QByteArray n(pinfo2.results[1], pinfo2.lengths[1]);
                QByteArray p(pinfo2.results[2], pinfo2.lengths[2]);
                *version  = (m.toUInt() << 16) | (n.toUInt() << 8) | p.toUInt();
            } else {
                ret = false;
                break;
            }
        } else if (qstrncmp("debug", pinfo.results[0], pinfo.lengths[0]) == 0) {
            *debug = qstrncmp("true", pinfo.results[1], pinfo.lengths[1]) == 0;
        } else if (qstrncmp("buildkey", pinfo.results[0],
                              pinfo.lengths[0]) == 0){
            // save buildkey
            *key = QByteArray(pinfo.results[1], pinfo.lengths[1] + 1);
        }
    } while (parse == 1 && parselen > 0);

    return ret;
}

#if defined(Q_OS_UNIX)

#if defined(Q_OS_FREEBSD) || defined(Q_OS_LINUX)
#  define USE_MMAP
#  include <sys/types.h>
#  include <sys/mman.h>
#endif // Q_OS_FREEBSD || Q_OS_LINUX

static long qt_find_pattern(const char *s, ulong s_len,
                             const char *pattern, ulong p_len)
{
    /*
      we search from the end of the file because on the supported
      systems, the read-only data/text segments are placed at the end
      of the file.  HOWEVER, when building with debugging enabled, all
      the debug symbols are placed AFTER the data/text segments.

      what does this mean?  when building in release mode, the search
      is fast because the data we are looking for is at the end of the
      file... when building in debug mode, the search is slower
      because we have to skip over all the debugging symbols first
    */

    if (! s || ! pattern || p_len > s_len) return -1;
    ulong i, hs = 0, hp = 0, delta = s_len - p_len;

    for (i = 0; i < p_len; ++i) {
        hs += s[delta + i];
        hp += pattern[i];
    }
    i = delta;
    for (;;) {
        if (hs == hp && qstrncmp(s + i, pattern, p_len) == 0)
            return i;
        if (i == 0)
            break;
        --i;
        hs -= s[i + p_len];
        hs += s[i];
    }

    return -1;
}

/*
  This opens the specified library, mmaps it into memory, and searches
  for the QT_PLUGIN_VERIFICATION_DATA.  The advantage of this approach is that
  we can get the verification data without have to actually load the library.
  This lets us detect mismatches more safely.

  Returns false if version/key information is not present, or if the
                information could not be read.
  Returns  true if version/key information is present and successfully read.
*/
static bool qt_unix_query(const QString &library, uint *version, bool *debug, QByteArray *key, QLibraryPrivate *lib = 0)
{
    QFile file(library);
    if (!file.open(QIODevice::ReadOnly)) {
        if (lib)
            lib->errorString = file.errorString();
        if (qt_debug_component()) {
            qWarning("%s: %s", (const char*) QFile::encodeName(library),
                qPrintable(qt_error_string(errno)));
        }
        return false;
    }

    QByteArray data;
    char *filedata = 0;
    ulong fdlen = 0;

#ifdef USE_MMAP
    char *mapaddr = 0;
    size_t maplen = file.size();
    mapaddr = (char *) mmap(mapaddr, maplen, PROT_READ, MAP_PRIVATE, file.handle(), 0);
    if (mapaddr != MAP_FAILED) {
        // mmap succeeded
        filedata = mapaddr;
        fdlen = maplen;
    } else {
        // mmap failed
        if (qt_debug_component()) {
            qWarning("mmap: %s", qPrintable(qt_error_string(errno)));
        }
        if (lib)
            lib->errorString = QLibrary::tr("Could not mmap '%1': %2")
                .arg(library)
                .arg(qt_error_string());
#endif // USE_MMAP
        // try reading the data into memory instead
        data = file.readAll();
        filedata = data.data();
        fdlen = data.size();
#ifdef USE_MMAP
    }
#endif // USE_MMAP

    // verify that the pattern is present in the plugin
    const char pattern[] = "pattern=QT_PLUGIN_VERIFICATION_DATA";
    const ulong plen = qstrlen(pattern);
    long pos = qt_find_pattern(filedata, fdlen, pattern, plen);

    bool ret = false;
    if (pos >= 0)
        ret = qt_parse_pattern(filedata + pos, version, debug, key);

    if (!ret && lib)
        lib->errorString = QLibrary::tr("Plugin verification data mismatch in '%1'").arg(library);
#ifdef USE_MMAP
    if (mapaddr != MAP_FAILED && munmap(mapaddr, maplen) != 0) {
        if (qt_debug_component())
            qWarning("munmap: %s", qPrintable(qt_error_string(errno)));
        if (lib)
            lib->errorString = QLibrary::tr("Could not unmap '%1': %2")
                .arg(library)
                .arg( qt_error_string() );
    }
#endif // USE_MMAP

    file.close();
    return ret;
}

#endif // Q_OS_UNIX

typedef QMap<QString, QLibraryPrivate*> LibraryMap;
Q_GLOBAL_STATIC(LibraryMap, libraryMap)

QLibraryPrivate::QLibraryPrivate(const QString &canonicalFileName, int verNum)
    :pHnd(0), fileName(canonicalFileName), majorVerNum(verNum), instance(0), qt_version(0),
     libraryRefCount(1), libraryUnloadCount(1), pluginState(MightBeAPlugin)
{ libraryMap()->insert(canonicalFileName, this); }

QLibraryPrivate *QLibraryPrivate::findOrCreate(const QString &fileName, int verNum)
{
    QMutexLocker locker(qt_library_mutex());
    if (QLibraryPrivate *lib = libraryMap()->value(fileName)) {
        lib->libraryUnloadCount.ref();
        lib->libraryRefCount.ref();
        return lib;
    }

    return new QLibraryPrivate(fileName, verNum);
}

QLibraryPrivate::~QLibraryPrivate()
{
    LibraryMap * const map = libraryMap();
    if (map) {
        QLibraryPrivate *that = map->take(fileName);
        Q_ASSERT(this == that);
  Q_UNUSED(that);
    }
}

void *QLibraryPrivate::resolve(const char *symbol)
{
    if (!pHnd)
        return 0;
    return resolve_sys(symbol);
}


bool QLibraryPrivate::load()
{
    if (pHnd)
        return true;
    if (fileName.isEmpty())
        return false;
    return load_sys();
}

bool QLibraryPrivate::unload()
{
    if (!pHnd)
        return true;
    if (!libraryUnloadCount.deref()) // only unload if ALL QLibrary instance wanted to
        if  (unload_sys())
            pHnd = 0;
    return (pHnd == 0);
}

void QLibraryPrivate::release()
{
    QMutexLocker locker(qt_library_mutex());
    if (!libraryRefCount.deref())
        delete this;
}

bool QLibraryPrivate::loadPlugin()
{
    if (instance)
        return true;
    if (load()) {
        instance = (QtPluginInstanceFunction)resolve("qt_plugin_instance");
        return instance;
    }
    return false;
}

bool QLibrary::isLibrary(const QString &fileName)
{
#if defined(Q_OS_WIN32)
    return fileName.endsWith(QLatin1String(".dll"));
#else
    QString completeSuffix = QFileInfo(fileName).completeSuffix();
    if (completeSuffix.isEmpty())
        return false;
    QStringList suffixes = completeSuffix.split(QLatin1Char('.'));
    QString suffix = suffixes.first();
# if defined(Q_OS_DARWIN)

    // On Mac, libs look like libmylib.1.0.0.dylib
    const QString lastSuffix = suffixes.at(suffixes.count() - 1);
    const QString firstSuffix = suffixes.at(0);

    bool valid = (lastSuffix == QLatin1String("dylib")
            || firstSuffix == QLatin1String("so")
            || firstSuffix == QLatin1String("bundle"));

    return valid;
# elif defined(Q_OS_HPUX)
/*
    See "HP-UX Linker and Libraries User's Guide", section "Link-time Differences between PA-RISC and IPF":
    "In PA-RISC (PA-32 and PA-64) shared libraries are suffixed with .sl. In IPF (32-bit and 64-bit),
    the shared libraries are suffixed with .so. For compatibility, the IPF linker also supports the .sl suffix."
 */
    bool valid = (suffix == QLatin1String("sl"));
#  if defined __ia64
    valid = valid || (suffix == QLatin1String("so"))
#  endif
# elif defined(Q_OS_AIX)
    bool valid = (suffix == QLatin1String("a") || suffix == QLatin1String("so"));
# elif defined(Q_OS_UNIX)
    bool valid = (suffix == QLatin1String("so"));
# else
    bool valid = false;
# endif

    for (int i = 1; i < suffixes.count() && valid; ++i)
        suffixes.at(i).toInt(&valid);
    return valid;
#endif

}

bool QLibraryPrivate::isPlugin()
{
    if (pluginState != MightBeAPlugin)
        return pluginState == IsAPlugin;

#ifndef QT_NO_PLUGIN_CHECK
    bool debug = !QLIBRARY_AS_DEBUG;
    QByteArray key;
    bool success = false;

    QFileInfo fileinfo(fileName);

#ifndef QT_NO_DATESTRING
    lastModified  = fileinfo.lastModified().toString(Qt::ISODate);
#endif
    QString regkey = QString::fromLatin1("Qt Plugin Cache %1.%2.%3/%4")
                     .arg((QT_VERSION & 0xff0000) >> 16)
                     .arg((QT_VERSION & 0xff00) >> 8)
                     .arg(QLIBRARY_AS_DEBUG ? QLatin1String("debug") : QLatin1String("false"))
                     .arg(fileName);
    QStringList reg;

    QSettings settings(QSettings::UserScope, QLatin1String("Trolltech"));
    reg = settings.value(regkey).toStringList();
    if (reg.count() == 4 && lastModified == reg.at(3)) {
        qt_version = reg.at(0).toUInt(0, 16);
        debug = bool(reg.at(1).toInt());
        key = reg.at(2).toLatin1();
        success = qt_version != 0;
    } else {
#if defined(Q_OS_UNIX)
        if (!pHnd) {
            // use unix shortcut to avoid loading the library
            success = qt_unix_query(fileName, &qt_version, &debug, &key, this);
        } else
#endif
        {
            bool temporary_load = false;
            if (!pHnd)
                temporary_load =  load_sys();
#  ifdef Q_CC_BOR
            typedef const char * __stdcall (*QtPluginQueryVerificationDataFunction)();
#  else
            typedef const char * (*QtPluginQueryVerificationDataFunction)();
#  endif
            QtPluginQueryVerificationDataFunction qtPluginQueryVerificationDataFunction =
                (QtPluginQueryVerificationDataFunction) resolve("qt_plugin_query_verification_data");

            if (!qtPluginQueryVerificationDataFunction
                || !qt_parse_pattern(qtPluginQueryVerificationDataFunction(), &qt_version, &debug, &key)) {
                qt_version = 0;
                key = "unknown";
                if (temporary_load)
                    unload_sys();
            } else {
                success = true;
            }
        }

        QStringList queried;
        queried << QString::number(qt_version,16)
                << QString::number((int)debug)
                << QLatin1String(key)
                << lastModified;
        settings.setValue(regkey, queried);
    }

    if (!success)
        return false;

    pluginState = IsNotAPlugin; // be pessimistic

    if ((qt_version > QT_VERSION) || ((QT_VERSION & 0xff0000) > (qt_version & 0xff0000))) {
        if (qt_debug_component()) {
            qWarning("In %s:\n"
                 "  Plugin uses incompatible Qt library (%d.%d.%d) [%s]",
                 (const char*) QFile::encodeName(fileName),
                 (qt_version&0xff0000) >> 16, (qt_version&0xff00) >> 8, qt_version&0xff,
                 debug ? "debug" : "release");
        }
        errorString = QLibrary::tr("The plugin '%1' uses incompatible Qt library. (%2.%3.%4) [%5]")
            .arg(fileName)
            .arg((qt_version&0xff0000) >> 16)
            .arg((qt_version&0xff00) >> 8)
            .arg(qt_version&0xff)
            .arg(debug ? QLatin1String("debug") : QLatin1String("release"));
    } else if (key != QT_BUILD_KEY) {
        if (qt_debug_component()) {
            qWarning("In %s:\n"
                 "  Plugin uses incompatible Qt library\n"
                 "  expected build key \"%s\", got \"%s\"",
                 (const char*) QFile::encodeName(fileName),
                 QT_BUILD_KEY,
                 key.isEmpty() ? "<null>" : (const char *) key);
        }
        errorString = QLibrary::tr("The plugin '%1' uses incompatible Qt library."
                 " Expected build key \"%2\", got \"%3\"")
                 .arg(fileName)
                 .arg(QLatin1String(QT_BUILD_KEY))
                 .arg(key.isEmpty() ? QLatin1String("<null>") : QLatin1String((const char *) key));
#ifndef QT_NO_DEBUG_PLUGIN_CHECK
    } else if(debug != QLIBRARY_AS_DEBUG) {
        //don't issue a qWarning since we will hopefully find a non-debug? --Sam
#endif
    } else {
        pluginState = IsAPlugin;
    }

    return pluginState == IsAPlugin;
#else
    return pluginState == MightBeAPlugin;
#endif
}

bool QLibrary::load()
{
    if (!d)
        return false;
    if (did_load)
        return d->pHnd;
    did_load = true;
    return d->load();
}

bool QLibrary::unload()
{
    if (did_load) {
        did_load = false;
        return d->unload();
    }
    return false;
}

bool QLibrary::isLoaded() const
{
    return d && d->pHnd;
}


QLibrary::QLibrary(QObject *parent)
    :QObject(parent), d(0), did_load(false)
{
}


QLibrary::QLibrary(const QString& fileName, QObject *parent)
    :QObject(parent), d(0), did_load(false)
{
    setFileName(fileName);
}


QLibrary::QLibrary(const QString& fileName, int verNum, QObject *parent)
    :QObject(parent), d(0), did_load(false)
{
    setFileNameAndVersion(fileName, verNum);
}

QLibrary::~QLibrary()
{
    if (d)
        d->release();
}


void QLibrary::setFileName(const QString &fileName)
{
    if (d) {
        d->release();
        d = 0;
        did_load = false;
    }
    d = QLibraryPrivate::findOrCreate(fileName);
    if (d && d->pHnd)
        did_load = true;

}

QString QLibrary::fileName() const
{
    if (d)
        return d->qualifiedFileName.isEmpty() ? d->fileName : d->qualifiedFileName;
    return QString();
}

void QLibrary::setFileNameAndVersion(const QString &fileName, int verNum)
{
    if (d) {
        d->release();
        d = 0;
        did_load = false;
    }
    d = QLibraryPrivate::findOrCreate(fileName, verNum);
    if (d && d->pHnd)
        did_load = true;
}

void *QLibrary::resolve(const char *symbol)
{
    if (!d)
        return 0;
    if (!d->pHnd)
        d->load();
    return d->resolve(symbol);
}

void *QLibrary::resolve(const QString &fileName, const char *symbol)
{
    QLibrary library(fileName);
    return library.resolve(symbol);
}

void *QLibrary::resolve(const QString &fileName, int verNum, const char *symbol)
{
    QLibrary library(fileName, verNum);
    return library.resolve(symbol);
}

QString QLibrary::errorString() const
{
    return d->errorString.isEmpty() ? tr("Unknown error") : d->errorString;
}

void QLibrary::setLoadHints(LoadHints hints)
{
    d->loadHints = hints;
}

QLibrary::LoadHints QLibrary::loadHints() const
{
    return d->loadHints;
}

/* Internal, for debugging */
bool qt_debug_component()
{
#if defined(QT_DEBUG_COMPONENT)
    return true;    //compatibility?
#else
    static int debug_env = -1;
    if (debug_env == -1)
       debug_env = ::qgetenv("QT_DEBUG_PLUGINS").toInt();

    return debug_env != 0;
#endif
}

#endif // QT_NO_LIBRARY

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