summaryrefslogtreecommitdiffstats
path: root/src/corelib/plugin/qlibrary.cpp
blob: 51b3a5030fae1526d67aece1a8e8556753dd4067 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the either Technology Preview License Agreement or the
** Beta Release License Agreement.
**
** GNU Lesser General Public License Usage
** Alternatively, 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 1.0, 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.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at http://qt.nokia.com/contact.
** $QT_END_LICENSE$
**
****************************************************************************/

#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>
#include <qdir.h>

QT_BEGIN_NAMESPACE

//#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)

/*!
    \class QLibrary
    \reentrant
    \brief The QLibrary class loads shared libraries at runtime.


    \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 and Symbian. 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.

    Note: In Symbian resolving symbols using their names is supported
    only if the library is built as STDDLL. Otherwise ordinals must
    be used. Also, in Symbian the path of the library is ignored and
    system default library location is always used.

    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.

    \snippet doc/src/snippets/code/src_corelib_plugin_qlibrary.cpp 0

    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:

    \snippet doc/src/snippets/code/src_corelib_plugin_qlibrary.cpp 1

    \sa QPluginLoader
*/

/*!
    \enum QLibrary::LoadHint

    This enum describes the possible hints that can be used to change the way
    libraries are handled when they are loaded. These values indicate how
    symbols are resolved when libraries are loaded, and are specified using
    the setLoadHints() function.

    \value ResolveAllSymbolsHint
    Causes all symbols in a library to be resolved when it is loaded, not
    simply when resolve() is called.
    \value ExportExternalSymbolsHint
    Exports unresolved and external symbols in the library so that they can be
    resolved in other dynamically-loaded libraries loaded later.
    \value LoadArchiveMemberHint
    Allows the file name of the library to specify a particular object file
    within an archive file.
    If this hint is given, the filename of the library consists of
    a path, which is a reference to an archive file, followed by
    a reference to the archive member.

    \sa loadHints
*/


#ifndef QT_NO_PLUGIN_CHECK
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]);
        }
    } while (parse == 1 && parselen > 0);

    return ret;
}
#endif // QT_NO_PLUGIN_CHECK

#if defined(Q_OS_UNIX) && !defined(Q_OS_MAC) && !defined(Q_OS_SYMBIAN) && !defined(QT_NO_PLUGIN_CHECK)

#if defined(Q_OS_FREEBSD) || defined(Q_OS_LINUX)
#  define USE_MMAP
QT_BEGIN_INCLUDE_NAMESPACE
#  include <sys/types.h>
#  include <sys/mman.h>
QT_END_INCLUDE_NAMESPACE
#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 && !Q_OS_MAC && !defined(Q_OS_SYMBIAN) && !defined(QT_NO_PLUGIN_CHECK)

typedef QMap<QString, QLibraryPrivate*> LibraryMap;

struct LibraryData {
    LibraryData() : settings(0) { }
    ~LibraryData() {
        delete settings;
    }

    QSettings *settings;
    LibraryMap libraryMap;
};

Q_GLOBAL_STATIC(LibraryData, libraryData)

static LibraryMap *libraryMap()
{
    LibraryData *data = libraryData();
    return data ? &data->libraryMap : 0;
}

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

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

    return new QLibraryPrivate(fileName, version);
}

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()
{
    libraryUnloadCount.ref();
    if (pHnd)
        return true;
    if (fileName.isEmpty())
        return false;
    return load_sys();
}

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

    return (pHnd == 0);
}

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

bool QLibraryPrivate::loadPlugin()
{
    if (instance) {
        libraryUnloadCount.ref();
        return true;
    }
    if (load()) {
        instance = (QtPluginInstanceFunction)resolve("qt_plugin_instance");
#if defined(Q_OS_SYMBIAN)
        if (!instance) {
            // If resolving with function name failed (i.e. not STDDLL),
            // try resolving using known ordinal, which for
            // qt_plugin_instance function is always "2".
            instance = (QtPluginInstanceFunction)resolve("2");
        }
#endif
        return instance;
    }
    return false;
}

/*!
    Returns true if \a fileName has a valid suffix for a loadable
    library; otherwise returns false.

    \table
    \header \i Platform \i Valid suffixes
    \row \i Windows     \i \c .dll
    \row \i Unix/Linux  \i \c .so
    \row \i AIX  \i \c .a
    \row \i HP-UX       \i \c .sl, \c .so (HP-UXi)
    \row \i Mac OS X    \i \c .dylib, \c .bundle, \c .so
    \endtable

    Trailing versioning numbers on Unix are ignored.
 */
bool QLibrary::isLibrary(const QString &fileName)
{
#if defined(Q_OS_WIN32) || defined(Q_OS_WINCE)
    return fileName.endsWith(QLatin1String(".dll"));
#elif defined(Q_OS_SYMBIAN)
    // Plugin stubs are also considered libraries in Symbian.
    return (fileName.endsWith(QLatin1String(".dll")) ||
            fileName.endsWith(QLatin1String(".qtplugin")));
#else
    QString completeSuffix = QFileInfo(fileName).completeSuffix();
    if (completeSuffix.isEmpty())
        return false;
    QStringList suffixes = completeSuffix.split(QLatin1Char('.'));
# 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;
# else  // Generic Unix
    QStringList validSuffixList;

#  if 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."
 */
    validSuffixList << QLatin1String("sl");
#   if defined __ia64
    validSuffixList << QLatin1String("so");
#   endif
#  elif defined(Q_OS_AIX)
    validSuffixList << QLatin1String("a") << QLatin1String("so");
#  elif defined(Q_OS_UNIX)
    validSuffixList << QLatin1String("so");
#  endif

    // Examples of valid library names:
    //  libfoo.so
    //  libfoo.so.0
    //  libfoo.so.0.3
    //  libfoo-0.3.so
    //  libfoo-0.3.so.0.3.0

    int suffix;
    int suffixPos = -1;
    for (suffix = 0; suffix < validSuffixList.count() && suffixPos == -1; ++suffix)
        suffixPos = suffixes.indexOf(validSuffixList.at(suffix));

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

}

bool QLibraryPrivate::isPlugin(QSettings *settings)
{
    errorString.clear();
    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;
#ifndef QT_NO_SETTINGS
    if (!settings) {
        settings = libraryData()->settings;
        if (!settings) {
            settings = new QSettings(QSettings::UserScope, QLatin1String("Trolltech"));
            libraryData()->settings = settings;
        }
    }
    reg = settings->value(regkey).toStringList();
#endif
    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) && !defined(Q_OS_MAC) && !defined(Q_OS_SYMBIAN)
        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;
#ifdef Q_OS_WIN
            HMODULE hTempModule = 0;
#endif
            if (!pHnd) {
#ifdef Q_OS_WIN
                hTempModule = ::LoadLibraryEx((wchar_t*)QDir::toNativeSeparators(fileName).utf16(), 0, DONT_RESOLVE_DLL_REFERENCES);
#else
#  if defined(Q_OS_SYMBIAN)
                //Guard against accidentally trying to load non-plugin libraries by making sure the stub exists
                if (fileinfo.exists())
#  endif
                temporary_load =  load_sys();
#endif
            }
#  ifdef Q_CC_BOR
            typedef const char * __stdcall (*QtPluginQueryVerificationDataFunction)();
#  else
            typedef const char * (*QtPluginQueryVerificationDataFunction)();
#  endif
#ifdef Q_OS_WIN
            QtPluginQueryVerificationDataFunction qtPluginQueryVerificationDataFunction = hTempModule
                ? (QtPluginQueryVerificationDataFunction)
#ifdef Q_OS_WINCE
                    ::GetProcAddress(hTempModule, L"qt_plugin_query_verification_data")
#else
                    ::GetProcAddress(hTempModule, "qt_plugin_query_verification_data")
#endif
                : (QtPluginQueryVerificationDataFunction) resolve("qt_plugin_query_verification_data");
#else
            QtPluginQueryVerificationDataFunction qtPluginQueryVerificationDataFunction = NULL;
#  if defined(Q_OS_SYMBIAN)
            if (temporary_load) {
                qtPluginQueryVerificationDataFunction = (QtPluginQueryVerificationDataFunction) resolve("qt_plugin_query_verification_data");
                // If resolving with function name failed (i.e. not STDDLL), try resolving using known ordinal
                if (!qtPluginQueryVerificationDataFunction)
                    qtPluginQueryVerificationDataFunction = (QtPluginQueryVerificationDataFunction) resolve("1");
            }
#  else
            qtPluginQueryVerificationDataFunction = (QtPluginQueryVerificationDataFunction) resolve("qt_plugin_query_verification_data");
#  endif
#endif

            if (!qtPluginQueryVerificationDataFunction
                || !qt_parse_pattern(qtPluginQueryVerificationDataFunction(), &qt_version, &debug, &key)) {
                qt_version = 0;
                key = "unknown";
                if (temporary_load)
                    unload_sys();
            } else {
                success = true;
            }
#ifdef Q_OS_WIN
            if (hTempModule) {
                BOOL ok = ::FreeLibrary(hTempModule);
                if (ok) {
                    hTempModule = 0;
                }

            }
#endif
        }

        // Qt 4.5 compatibility: stl doesn't affect binary compatibility
        key.replace(" no-stl", "");

#ifndef QT_NO_SETTINGS
        QStringList queried;
        queried << QString::number(qt_version,16)
                << QString::number((int)debug)
                << QLatin1String(key)
                << lastModified;
        settings->setValue(regkey, queried);
#endif
    }

    if (!success) {
        if (errorString.isEmpty()){
            if (fileName.isEmpty())
                errorString = QLibrary::tr("The shared library was not found.");
            else
                errorString = QLibrary::tr("The file '%1' is not a valid Qt plugin.").arg(fileName);
        }
        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
#ifdef QT_BUILD_KEY_COMPAT
               // be sure to load plugins using an older but compatible build key
               && key != QT_BUILD_KEY_COMPAT
#endif
               ) {
        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
        errorString = QLibrary::tr("The plugin '%1' uses incompatible Qt library."
                 " (Cannot mix debug and release libraries.)").arg(fileName);
#endif
    } else {
        pluginState = IsAPlugin;
    }

    return pluginState == IsAPlugin;
#else
    Q_UNUSED(settings);
    return pluginState == MightBeAPlugin;
#endif
}

/*!
    Loads the library and returns true if the library was loaded
    successfully; otherwise returns false. Since resolve() always
    calls this function before resolving any symbols it is not
    necessary to call it explicitly. In some situations you might want
    the library loaded in advance, in which case you would use this
    function.

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

/*!
    Unloads the library and returns true if the library could be
    unloaded; otherwise returns false.

    This happens automatically on application termination, so you
    shouldn't normally need to call this function.

    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().

    Note that on Mac OS X 10.3 (Panther), dynamic libraries cannot be unloaded.

    \sa resolve(), load()
*/
bool QLibrary::unload()
{
    if (did_load) {
        did_load = false;
        return d->unload();
    }
    return false;
}

/*!
    Returns true if the library is loaded; otherwise returns false.

    \sa load()
 */
bool QLibrary::isLoaded() const
{
    return d && d->pHnd;
}


/*!
    Constructs a library with the given \a parent.
 */
QLibrary::QLibrary(QObject *parent)
    :QObject(parent), d(0), did_load(false)
{
}


/*!
    Constructs a library object with the given \a parent that will
    load the library specified by \a fileName.

    We recommend omitting the file's suffix in \a fileName, since
    QLibrary will automatically look for the file with the appropriate
    suffix in accordance with the platform, e.g. ".so" on Unix,
    ".dylib" on Mac OS X, and ".dll" on Windows. (See \l{fileName}.)

    Note: In Symbian the path portion of the \a fileName is ignored.
 */
QLibrary::QLibrary(const QString& fileName, QObject *parent)
    :QObject(parent), d(0), did_load(false)
{
    setFileName(fileName);
}


/*!
    Constructs a library object with the given \a parent that will
    load the library specified by \a fileName and major version number \a verNum.
    Currently, the version number is ignored on Windows and Symbian.

    We recommend omitting the file's suffix in \a fileName, since
    QLibrary will automatically look for the file with the appropriate
    suffix in accordance with the platform, e.g. ".so" on Unix,
    ".dylib" on Mac OS X, and ".dll" on Windows. (See \l{fileName}.)

    Note: In Symbian the path portion of the \a fileName is ignored.
*/
QLibrary::QLibrary(const QString& fileName, int verNum, QObject *parent)
    :QObject(parent), d(0), did_load(false)
{
    setFileNameAndVersion(fileName, verNum);
}

/*!
    Constructs a library object with the given \a parent that will
    load the library specified by \a fileName and full version number \a version.
    Currently, the version number is ignored on Windows and Symbian.

    We recommend omitting the file's suffix in \a fileName, since
    QLibrary will automatically look for the file with the appropriate
    suffix in accordance with the platform, e.g. ".so" on Unix,
    ".dylib" on Mac OS X, and ".dll" on Windows. (See \l{fileName}.)

    Note: In Symbian the path portion of the \a fileName is ignored.
 */
QLibrary::QLibrary(const QString& fileName, const QString &version, QObject *parent)
    :QObject(parent), d(0), did_load(false)
{
    setFileNameAndVersion(fileName, version);
}

/*!
    Destroys the QLibrary object.

    Unless unload() was called explicitly, the library stays in memory
    until the application terminates.

    \sa isLoaded(), unload()
*/
QLibrary::~QLibrary()
{
    if (d)
        d->release();
}


/*!
    \property QLibrary::fileName
    \brief the file name of the library

    We recommend omitting the file's suffix in the file name, since
    QLibrary will automatically look for the file with the appropriate
    suffix (see isLibrary()).

    When loading the library, QLibrary searches in all system-specific
    library locations (e.g. \c LD_LIBRARY_PATH on Unix), unless the
    file name has an absolute path. After loading the library
    successfully, fileName() returns the fully-qualified file name of
    the library, including the full path to the library if one was given
    in the constructor or passed to setFileName().

    For example, after successfully loading the "GL" library on Unix
    platforms, fileName() will return "libGL.so". If the file name was
    originally passed as "/usr/lib/libGL", fileName() will return
    "/usr/lib/libGL.so".

    Note: In Symbian the path portion of the \a fileName is ignored.
*/

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

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

/*!
    \fn void QLibrary::setFileNameAndVersion(const QString &fileName, int versionNumber)

    Sets the fileName property and major version number to \a fileName
    and \a versionNumber respectively.
    The \a versionNumber is ignored on Windows and Symbian.

    Note: In Symbian the path portion of the \a fileName is ignored.

    \sa setFileName()
*/
void QLibrary::setFileNameAndVersion(const QString &fileName, int verNum)
{
    QLibrary::LoadHints lh;
    if (d) {
        lh = d->loadHints;
        d->release();
        d = 0;
        did_load = false;
    }
    d = QLibraryPrivate::findOrCreate(fileName, verNum >= 0 ? QString::number(verNum) : QString());
    d->loadHints = lh;
}

/*!
    \since 4.4

    Sets the fileName property and full version number to \a fileName
    and \a version respectively.
    The \a version parameter is ignored on Windows and Symbian.

    Note: In Symbian the path portion of the \a fileName is ignored.

    \sa setFileName()
*/
void QLibrary::setFileNameAndVersion(const QString &fileName, const QString &version)
{
    QLibrary::LoadHints lh;
    if (d) {
        lh = d->loadHints;
        d->release();
        d = 0;
        did_load = false;
    }
    d = QLibraryPrivate::findOrCreate(fileName, version);
    d->loadHints = lh;
}

/*!
    Returns the address of the exported symbol \a symbol. The library is
    loaded if necessary. The function returns 0 if the symbol could
    not be resolved or if the library could not be loaded.

    Example:
    \snippet doc/src/snippets/code/src_corelib_plugin_qlibrary.cpp 2

    The symbol must be exported as a C function from the library. This
    means that the function must be wrapped in an \c{extern "C"} if
    the library is compiled with a C++ compiler. On Windows you must
    also explicitly export the function from the DLL using the
    \c{__declspec(dllexport)} compiler directive, for example:

    \snippet doc/src/snippets/code/src_corelib_plugin_qlibrary.cpp 3

    with \c MY_EXPORT defined as

    \snippet doc/src/snippets/code/src_corelib_plugin_qlibrary.cpp 4

    Note: In Symbian resolving with symbol names works only if the loaded
    library was built as STDDLL. Otherwise, the ordinals must be used.
*/
void *QLibrary::resolve(const char *symbol)
{
    if (!load())
        return 0;
    return d->resolve(symbol);
}

/*!
    \overload

    Loads the library \a fileName and returns the address of the
    exported symbol \a symbol. Note that \a fileName should not
    include the platform-specific file suffix; (see \l{fileName}). The
    library remains loaded until the application exits.

    The function returns 0 if the symbol could not be resolved or if
    the library could not be loaded.

    Note: In Symbian resolving with symbol names works only if the loaded
    library was built as STDDLL. Otherwise, the ordinals must be used.

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

/*!
    \overload

    Loads the library \a fileName with major version number \a verNum and
    returns the address of the exported symbol \a symbol.
    Note that \a fileName should not include the platform-specific file suffix;
    (see \l{fileName}). The library remains loaded until the application exits.
    \a verNum is ignored on Windows.

    The function returns 0 if the symbol could not be resolved or if
    the library could not be loaded.

    Note: In Symbian resolving with symbol names works only if the loaded
    library was built as STDDLL. Otherwise, the ordinals must be used.

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

/*!
    \overload
    \since 4.4

    Loads the library \a fileName with full version number \a version and
    returns the address of the exported symbol \a symbol.
    Note that \a fileName should not include the platform-specific file suffix;
    (see \l{fileName}). The library remains loaded until the application exits.
    \a version is ignored on Windows.

    The function returns 0 if the symbol could not be resolved or if
    the library could not be loaded.

    Note: In Symbian resolving with symbol names works only if the loaded
    library was built as STDDLL. Otherwise, the ordinals must be used.

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

/*!
    \fn QString QLibrary::library() const

    Use fileName() instead.
*/

/*!
    \fn void QLibrary::setAutoUnload( bool b )

    Use load(), isLoaded(), and unload() as necessary instead.
*/

/*!
    \since 4.2

    Returns a text string with the description of the last error that occurred.
    Currently, errorString will only be set if load(), unload() or resolve() for some reason fails.
*/
QString QLibrary::errorString() const
{
    return (!d || d->errorString.isEmpty()) ? tr("Unknown error") : d->errorString;
}

/*!
    \property QLibrary::loadHints
    \brief Give the load() function some hints on how it should behave.

    You can give some hints on how the symbols are resolved. Usually,
    the symbols are not resolved at load time, but resolved lazily,
    (that is, when resolve() is called). If you set the loadHint to
    ResolveAllSymbolsHint, then all symbols will be resolved at load time
    if the platform supports it.

    Setting ExportExternalSymbolsHint will make the external symbols in the
    library available for resolution in subsequent loaded libraries.

    If LoadArchiveMemberHint is set, the file name
    is composed of two components: A path which is a reference to an
    archive file followed by the second component which is the reference to
    the archive member. For instance, the fileName \c libGL.a(shr_64.o) will refer
    to the library \c shr_64.o in the archive file named \c libGL.a. This
    is only supported on the AIX platform.

    The interpretation of the load hints is platform dependent, and if
    you use it you are probably making some assumptions on which platform
    you are compiling for, so use them only if you understand the consequences
    of them.

    By default, none of these flags are set, so libraries will be loaded with
    lazy symbol resolution, and will not export external symbols for resolution
    in other dynamically-loaded libraries.
*/
void QLibrary::setLoadHints(LoadHints hints)
{
    if (!d) {
        d = QLibraryPrivate::findOrCreate(QString());   // ugly, but we need a d-ptr
        d->errorString.clear();
    }
    d->loadHints = hints;
}

QLibrary::LoadHints QLibrary::loadHints() const
{
    return d ? d->loadHints : (QLibrary::LoadHints)0;
}

/* 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 = QT_PREPEND_NAMESPACE(qgetenv)("QT_DEBUG_PLUGINS").toInt();

    return debug_env != 0;
#endif
}

QT_END_NAMESPACE

#endif // QT_NO_LIBRARY