/******************************************************************************** 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#endifQ_GLOBAL_STATIC(QMutex, qt_library_mutex)/*!    \class QLibrary    \reentrant    \brief The QLibrary class loads shared libraries at runtime.    \mainclass    \ingroup plugins    An instance of a QLibrary object operates on a single shared    object file (which we call a "library", but is also known as a    "DLL"). A QLibrary provides access to the functionality in the    library in a platform independent way. You can either pass a file    name in the constructor, or set it explicitly with setFileName().    When loading the library, QLibrary searches in all the    system-specific library locations (e.g. \c LD_LIBRARY_PATH on    Unix), unless the file name has an absolute path. If the file    cannot be found, QLibrary tries the name with different    platform-specific file suffixes, like ".so" on Unix, ".dylib" on    the Mac, or ".dll" on Windows. This makes it possible to specify    shared libraries that are only identified by their basename (i.e.    without their suffix), so the same code will work on different    operating systems.    The most important functions are load() to dynamically load the    library file, isLoaded() to check whether loading was successful,    and resolve() to resolve a symbol in the library. The resolve()    function implicitly tries to load the library if it has not been    loaded yet. Multiple instances of QLibrary can be used to access    the same physical library. Once loaded, libraries remain in memory    until the application terminates. You can attempt to unload a    library using unload(), but if other instances of QLibrary are    using the same library, the call will fail, and unloading will    only happen when every instance has called unload().    A typical use of QLibrary is to resolve an exported symbol in a    library, and to call the C function that this symbol represents.    This is called "explicit linking" in contrast to "implicit    linking", which is done by the link step in the build process when    linking an executable against a library.    The following code snippet loads a library, resolves the symbol    "mysymbol", and calls the function if everything succeeded. If    something goes wrong, e.g. the library file does not exist or the    symbol is not defined, the function pointer will be 0 and won't be    called.    \code        QLibrary myLib("mylib");        typedef void (*MyPrototype)();        MyPrototype myFunction = (MyPrototype) myLib.resolve("mysymbol");        if (myFunction)            myFunction();    \endcode    The symbol must be exported as a C function from the library for    resolve() to work. This means that the function must be wrapped in    an \c{extern "C"} block if the library is compiled with a C++    compiler. On Windows, this also requires the use of a \c dllexport    macro; see resolve() for the details of how this is done. For    convenience, there is a static resolve() function which you can    use if you just want to call a function in a library without    explicitly loading the library first:    \code        typedef void (*MyPrototype)();        MyPrototype myFunction =                (MyPrototype) QLibrary::resolve("mylib", "mysymbol");        if (myFunction)            myFunction();    \endcode    \sa QPluginLoader*//*!    \enum QLibrary::LoadHint    This enum gives hints as to how symbols are resolved by     specifying load hints with the \c setLoadHints() function.           \value ResolveAllSymbolsHint	This value indicates that all symbols should be resolved at	load time, not when \c resolve() is called.	    \value ExportExternalSymbolsHint	This makes external symbols in the library available for	subsequent loaded libraries.	    \value LoadArchiveMemberHint	If this hint is given, the filename of the library consists of	two parts:	A path which is a reference to an archive file followed by 	the second component which is the reference to the archive 	member.	    \sa setLoadHints()*/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_LINUXstatic 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)) {