about summary refs log tree commit diff
path: root/src/nix-env/nix-env.cc
blob: 4a9df454d4ff964844827838ebd2ce83f16c5e23 (plain) (blame)
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
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
#include "profiles.hh"
#include "names.hh"
#include "globals.hh"
#include "misc.hh"
#include "shared.hh"
#include "parser.hh"
#include "eval.hh"
#include "help.txt.hh"
#include "get-drvs.hh"
#include "attr-path.hh"
#include "common-opts.hh"
#include "xml-writer.hh"
#include "store-api.hh"
#include "user-env.hh"
#include "util.hh"

#include <cerrno>
#include <ctime>
#include <algorithm>
#include <iostream>
#include <sstream>

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>


using namespace nix;
using std::cout;


typedef enum {
    srcNixExprDrvs,
    srcNixExprs,
    srcStorePaths,
    srcProfile,
    srcAttrPath,
    srcUnknown
} InstallSourceType;


struct InstallSourceInfo
{
    InstallSourceType type;
    Path nixExprPath; /* for srcNixExprDrvs, srcNixExprs */
    Path profile; /* for srcProfile */
    string systemFilter; /* for srcNixExprDrvs */
    bool prebuiltOnly;
    Bindings autoArgs;
    InstallSourceInfo() : prebuiltOnly(false) { };
};


struct Globals
{
    InstallSourceInfo instSource;
    Path profile;
    EvalState state;
    bool dryRun;
    bool preserveInstalled;
    bool keepDerivations;
    string forceName;
};


typedef void (* Operation) (Globals & globals,
    Strings args, Strings opFlags, Strings opArgs);


void printHelp()
{
    cout << string((char *) helpText, sizeof helpText);
}


static string needArg(Strings::iterator & i,
    Strings & args, const string & arg)
{
    if (i == args.end()) throw UsageError(
        format("`%1%' requires an argument") % arg);
    return *i++;
}


static bool parseInstallSourceOptions(Globals & globals,
    Strings::iterator & i, Strings & args, const string & arg)
{
    if (arg == "--from-expression" || arg == "-E")
        globals.instSource.type = srcNixExprs;
    else if (arg == "--from-profile") {
        globals.instSource.type = srcProfile;
        globals.instSource.profile = needArg(i, args, arg);
    }
    else if (arg == "--attr" || arg == "-A")
        globals.instSource.type = srcAttrPath;
    else if (arg == "--prebuilt-only" || arg == "-b")
        globals.instSource.prebuiltOnly = true;
    else return false;
    return true;
}


static bool isNixExpr(const Path & path)
{
    struct stat st;
    if (stat(path.c_str(), &st) == -1)
        throw SysError(format("getting information about `%1%'") % path);

    return !S_ISDIR(st.st_mode) || pathExists(path + "/default.nix");
}


static void getAllExprs(EvalState & state,
    const Path & path, ExprAttrs & attrs)
{
    Strings names = readDirectory(path);
    StringSet namesSorted(names.begin(), names.end());

    foreach (StringSet::iterator, i, namesSorted) {
        Path path2 = path + "/" + *i;
        
        struct stat st;
        if (stat(path2.c_str(), &st) == -1)
            continue; // ignore dangling symlinks in ~/.nix-defexpr
        
        if (isNixExpr(path2)) {
            /* Strip off the `.nix' filename suffix (if applicable),
               otherwise the attribute cannot be selected with the
               `-A' option.  Useful if you want to stick a Nix
               expression directly in ~/.nix-defexpr. */
            string attrName = *i;
            if (hasSuffix(attrName, ".nix"))
                attrName = string(attrName, 0, attrName.size() - 4);
            attrs.attrs[state.symbols.create(attrName)] =
                parseExprFromFile(state, absPath(path2));
        }
        else
            /* `path2' is a directory (with no default.nix in it);
               recurse into it. */
            getAllExprs(state, path2, attrs);
    }
}


static Expr * loadSourceExpr(EvalState & state, const Path & path)
{
    if (isNixExpr(path)) return parseExprFromFile(state, absPath(path));

    /* The path is a directory.  Put the Nix expressions in the
       directory in an attribute set, with the file name of each
       expression as the attribute name.  Recurse into subdirectories
       (but keep the attribute set flat, not nested, to make it easier
       for a user to have a ~/.nix-defexpr directory that includes
       some system-wide directory). */
    ExprAttrs * attrs = new ExprAttrs;
    attrs->attrs[state.symbols.create("_combineChannels")] = new ExprList();
    getAllExprs(state, path, *attrs);
    return attrs;
}


static void loadDerivations(EvalState & state, Path nixExprPath,
    string systemFilter, const Bindings & autoArgs,
    const string & pathPrefix, DrvInfos & elems)
{
    Value v;
    findAlongAttrPath(state, pathPrefix, autoArgs, loadSourceExpr(state, nixExprPath), v);
    
    getDerivations(state, v, pathPrefix, autoArgs, elems);

    /* Filter out all derivations not applicable to the current
       system. */
    for (DrvInfos::iterator i = elems.begin(), j; i != elems.end(); i = j) {
        j = i; j++;
        if (systemFilter != "*" && i->system != systemFilter)
            elems.erase(i);
    }
}


static Path getHomeDir()
{
    Path homeDir(getEnv("HOME", ""));
    if (homeDir == "") throw Error("HOME environment variable not set");
    return homeDir;
}


static Path getDefNixExprPath()
{
    return getHomeDir() + "/.nix-defexpr";
}


static int getPriority(EvalState & state, const DrvInfo & drv)
{
    MetaValue value = drv.queryMetaInfo(state, "priority");
    int prio = 0;
    if (value.type == MetaValue::tpInt) prio = value.intValue;
    else if (value.type == MetaValue::tpString)
        /* Backwards compatibility.  Priorities used to be strings
           before we had support for integer meta field. */
        string2Int(value.stringValue, prio);
    return prio;
}


static int comparePriorities(EvalState & state,
    const DrvInfo & drv1, const DrvInfo & drv2)
{
    return getPriority(state, drv2) - getPriority(state, drv1);
}


static bool isPrebuilt(EvalState & state, const DrvInfo & elem)
{
    return
        store->isValidPath(elem.queryOutPath(state)) ||
        store->hasSubstitutes(elem.queryOutPath(state));
}


static DrvInfos filterBySelector(EvalState & state, const DrvInfos & allElems,
    const Strings & args, bool newestOnly, bool prebuiltOnly)
{
    DrvNames selectors = drvNamesFromArgs(args);

    DrvInfos elems;
    set<unsigned int> done;

    for (DrvNames::iterator i = selectors.begin();
         i != selectors.end(); ++i)
    {
        typedef list<std::pair<DrvInfo, unsigned int> > Matches;
        Matches matches;
        unsigned int n = 0;
        for (DrvInfos::const_iterator j = allElems.begin();
             j != allElems.end(); ++j, ++n)
        {
            DrvName drvName(j->name);
            if (i->matches(drvName)) {
                i->hits++;
                if (!prebuiltOnly || isPrebuilt(state, *j))
                    matches.push_back(std::pair<DrvInfo, unsigned int>(*j, n));
            }
        }

        /* If `newestOnly', if a selector matches multiple derivations
           with the same name, pick the one with the highest priority.
           If there are multiple derivations with the same priority,
           pick the one with the highest version.  If there are
           multiple derivations with the same priority and name and
           version, then pick the first one. */
        if (newestOnly) {

            /* Map from package names to derivations. */
            typedef map<string, std::pair<DrvInfo, unsigned int> > Newest;
            Newest newest;
            StringSet multiple;

            for (Matches::iterator j = matches.begin(); j != matches.end(); ++j) {
                DrvName drvName(j->first.name);
                int d = 1;

                Newest::iterator k = newest.find(drvName.name);
                
                if (k != newest.end()) {
                    d = comparePriorities(state, j->first, k->second.first);
                    if (d == 0)
                        d = compareVersions(drvName.version, DrvName(k->second.first.name).version);
                }

                if (d > 0) {
                    newest[drvName.name] = *j;
                    multiple.erase(j->first.name);
                } else if (d == 0) {
                    multiple.insert(j->first.name);
                }
            }

            matches.clear();
            for (Newest::iterator j = newest.begin(); j != newest.end(); ++j) {
                if (multiple.find(j->second.first.name) != multiple.end())
                    printMsg(lvlInfo,
                        format("warning: there are multiple derivations named `%1%'; using the first one")
                        % j->second.first.name);
                matches.push_back(j->second);
            }
        }

        /* Insert only those elements in the final list that we
           haven't inserted before. */
        for (Matches::iterator j = matches.begin(); j != matches.end(); ++j)
            if (done.find(j->second) == done.end()) {
                done.insert(j->second);
                elems.push_back(j->first);
            }
    }
            
    /* Check that all selectors have been used. */
    for (DrvNames::iterator i = selectors.begin();
         i != selectors.end(); ++i)
        if (i->hits == 0 && i->fullName != "*")
            throw Error(format("selector `%1%' matches no derivations")
                % i->fullName);

    return elems;
}


static bool isPath(const string & s)
{
    return s.find('/') != string::npos;
}


static void queryInstSources(EvalState & state,
    const InstallSourceInfo & instSource, const Strings & args,
    DrvInfos & elems, bool newestOnly)
{
    InstallSourceType type = instSource.type;
    if (type == srcUnknown && args.size() > 0 && isPath(args.front()))
        type = srcStorePaths;
    
    switch (type) {

        /* Get the available user environment elements from the
           derivations specified in a Nix expression, including only
           those with names matching any of the names in `args'. */
        case srcUnknown:
        case srcNixExprDrvs: {

            /* Load the derivations from the (default or specified)
               Nix expression. */
            DrvInfos allElems;
            loadDerivations(state, instSource.nixExprPath,
                instSource.systemFilter, instSource.autoArgs, "", allElems);

            elems = filterBySelector(state, allElems, args,
                newestOnly, instSource.prebuiltOnly);
    
            break;
        }

        /* Get the available user environment elements from the Nix
           expressions specified on the command line; these should be
           functions that take the default Nix expression file as
           argument, e.g., if the file is `./foo.nix', then the
           argument `x: x.bar' is equivalent to `(x: x.bar)
           (import ./foo.nix)' = `(import ./foo.nix).bar'. */
        case srcNixExprs: {
                
            Expr * e1 = loadSourceExpr(state, instSource.nixExprPath);

            foreach (Strings::const_iterator, i, args) {
                Expr * e2 = parseExprFromString(state, *i, absPath("."));
                Expr * call = new ExprApp(e2, e1);
                Value v; state.eval(call, v);
                getDerivations(state, v, "", instSource.autoArgs, elems);
            }
            
            break;
        }
            
        /* The available user environment elements are specified as a
           list of store paths (which may or may not be
           derivations). */
        case srcStorePaths: {

            for (Strings::const_iterator i = args.begin();
                 i != args.end(); ++i)
            {
                Path path = followLinksToStorePath(*i);

                DrvInfo elem;
                elem.attrs = new Bindings;
                string name = baseNameOf(path);
                string::size_type dash = name.find('-');
                if (dash != string::npos)
                    name = string(name, dash + 1);

                if (isDerivation(path)) {
                    elem.setDrvPath(path);
                    elem.setOutPath(findOutput(derivationFromPath(path), "out"));
                    if (name.size() >= drvExtension.size() &&
                        string(name, name.size() - drvExtension.size()) == drvExtension)
                        name = string(name, 0, name.size() - drvExtension.size());
                }
                else elem.setOutPath(path);

                elem.name = name;

                elems.push_back(elem);
            }
            
            break;
        }
            
        /* Get the available user environment elements from another
           user environment.  These are then filtered as in the
           `srcNixExprDrvs' case. */
        case srcProfile: {
            elems = filterBySelector(state,
                queryInstalled(state, instSource.profile),
                args, newestOnly, instSource.prebuiltOnly);
            break;
        }

        case srcAttrPath: {
            foreach (Strings::const_iterator, i, args) {
                Value v;
                findAlongAttrPath(state, *i, instSource.autoArgs,
                    loadSourceExpr(state, instSource.nixExprPath), v);
                getDerivations(state, v, "", instSource.autoArgs, elems);
            }
            break;
        }
    }
}


static void printMissing(EvalState & state, const DrvInfos & elems)
{
    PathSet targets;
    foreach (DrvInfos::const_iterator, i, elems) {
        Path drvPath = i->queryDrvPath(state);
        if (drvPath != "")
            targets.insert(drvPath);
        else
            targets.insert(i->queryOutPath(state));
    }

    printMissing(targets);
}


static bool keep(MetaInfo & meta)
{
    MetaValue value = meta["keep"];
    return value.type == MetaValue::tpString && value.stringValue == "true";
}


static void installDerivations(Globals & globals,
    const Strings & args, const Path & profile)
{
    debug(format("installing derivations"));

    /* Get the set of user environment elements to be installed. */
    DrvInfos newElems;
    queryInstSources(globals.state, globals.instSource, args, newElems, true);

    StringSet newNames;
    for (DrvInfos::iterator i = newElems.begin(); i != newElems.end(); ++i) {
        /* `forceName' is a hack to get package names right in some
           one-click installs, namely those where the name used in the
           path is not the one we want (e.g., `java-front' versus
           `java-front-0.9pre15899'). */
        if (globals.forceName != "")
            i->name = globals.forceName;
        newNames.insert(DrvName(i->name).name);
    }

    /* Add in the already installed derivations, unless they have the
       same name as a to-be-installed element. */

    while (true) {
        string lockToken = optimisticLockProfile(profile);
        
        DrvInfos installedElems = queryInstalled(globals.state, profile);
        
        DrvInfos allElems(newElems);
        foreach (DrvInfos::iterator, i, installedElems) {
            DrvName drvName(i->name);
            MetaInfo meta = i->queryMetaInfo(globals.state);
            if (!globals.preserveInstalled &&
                newNames.find(drvName.name) != newNames.end() &&
                !keep(meta))
                printMsg(lvlInfo,
                    format("replacing old `%1%'") % i->name);
            else
                allElems.push_back(*i);
        }

        foreach (DrvInfos::iterator, i, newElems)
            printMsg(lvlInfo, format("installing `%1%'") % i->name);
    
        printMissing(globals.state, newElems);
    
        if (globals.dryRun) return;

        if (createUserEnv(globals.state, allElems,
                profile, globals.keepDerivations, lockToken)) break;
    }
}


static void opInstall(Globals & globals,
    Strings args, Strings opFlags, Strings opArgs)
{
    for (Strings::iterator i = opFlags.begin(); i != opFlags.end(); ) {
        string arg = *i++;
        if (parseInstallSourceOptions(globals, i, opFlags, arg)) ;
        else if (arg == "--preserve-installed" || arg == "-P")
            globals.preserveInstalled = true;
        else throw UsageError(format("unknown flag `%1%'") % arg);
    }

    installDerivations(globals, opArgs, globals.profile);
}


typedef enum { utLt, utLeq, utEq, utAlways } UpgradeType;


static void upgradeDerivations(Globals & globals,
    const Strings & args, UpgradeType upgradeType)
{
    debug(format("upgrading derivations"));

    /* Upgrade works as follows: we take all currently installed
       derivations, and for any derivation matching any selector, look
       for a derivation in the input Nix expression that has the same
       name and a higher version number. */

    while (true) {
        string lockToken = optimisticLockProfile(globals.profile);
        
        DrvInfos installedElems = queryInstalled(globals.state, globals.profile);

        /* Fetch all derivations from the input file. */
        DrvInfos availElems;
        queryInstSources(globals.state, globals.instSource, args, availElems, false);

        /* Go through all installed derivations. */
        DrvInfos newElems;
        foreach (DrvInfos::iterator, i, installedElems) {
            DrvName drvName(i->name);

            try {

                MetaInfo meta = i->queryMetaInfo(globals.state);
                if (keep(meta)) {
                    newElems.push_back(*i);
                    continue;
                }

                /* Find the derivation in the input Nix expression
                   with the same name that satisfies the version
                   constraints specified by upgradeType.  If there are
                   multiple matches, take the one with the highest
                   priority.  If there are still multiple matches,
                   take the one with the highest version. */
                DrvInfos::iterator bestElem = availElems.end();
                DrvName bestName;
                foreach (DrvInfos::iterator, j, availElems) {
                    DrvName newName(j->name);
                    if (newName.name == drvName.name) {
                        int d = comparePriorities(globals.state, *i, *j);
                        if (d == 0) d = compareVersions(drvName.version, newName.version);
                        if ((upgradeType == utLt && d < 0) ||
                            (upgradeType == utLeq && d <= 0) ||
                            (upgradeType == utEq && d == 0) ||
                            upgradeType == utAlways)
                        {
                            int d2 = -1;
                            if (bestElem != availElems.end()) {
                                d2 = comparePriorities(globals.state, *bestElem, *j);
                                if (d2 == 0) d2 = compareVersions(bestName.version, newName.version);
                            }
                            if (d2 < 0) {
                                bestElem = j;
                                bestName = newName;
                            }
                        }
                    }
                }
                
                if (bestElem != availElems.end() &&
                    i->queryOutPath(globals.state) !=
                    bestElem->queryOutPath(globals.state))
                {
                    printMsg(lvlInfo,
                        format("upgrading `%1%' to `%2%'")
                        % i->name % bestElem->name);
                    newElems.push_back(*bestElem);
                } else newElems.push_back(*i);

            } catch (Error & e) {
                e.addPrefix(format("while trying to find an upgrade for `%1%':\n") % i->name);
                throw;
            }
        }
    
        printMissing(globals.state, newElems);
    
        if (globals.dryRun) return;

        if (createUserEnv(globals.state, newElems,
                globals.profile, globals.keepDerivations, lockToken)) break;
    }
}


static void opUpgrade(Globals & globals,
    Strings args, Strings opFlags, Strings opArgs)
{
    UpgradeType upgradeType = utLt;
    for (Strings::iterator i = opFlags.begin(); i != opFlags.end(); ) {
        string arg = *i++;
        if (parseInstallSourceOptions(globals, i, opFlags, arg)) ;
        else if (arg == "--lt") upgradeType = utLt;
        else if (arg == "--leq") upgradeType = utLeq;
        else if (arg == "--eq") upgradeType = utEq;
        else if (arg == "--always") upgradeType = utAlways;
        else throw UsageError(format("unknown flag `%1%'") % arg);
    }

    upgradeDerivations(globals, opArgs, upgradeType);
}


static void setMetaFlag(EvalState & state, DrvInfo & drv,
    const string & name, const string & value)
{
    MetaInfo meta = drv.queryMetaInfo(state);
    MetaValue v;
    v.type = MetaValue::tpString;
    v.stringValue = value;
    meta[name] = v;
    drv.setMetaInfo(meta);
}


static void opSetFlag(Globals & globals,
    Strings args, Strings opFlags, Strings opArgs)
{
    if (opFlags.size() > 0)
        throw UsageError(format("unknown flag `%1%'") % opFlags.front());
    if (opArgs.size() < 2)
        throw UsageError("not enough arguments to `--set-flag'");

    Strings::iterator arg = opArgs.begin();
    string flagName = *arg++;
    string flagValue = *arg++;
    DrvNames selectors = drvNamesFromArgs(Strings(arg, opArgs.end()));

    while (true) {
        string lockToken = optimisticLockProfile(globals.profile);

        DrvInfos installedElems = queryInstalled(globals.state, globals.profile);

        /* Update all matching derivations. */
        foreach (DrvInfos::iterator, i, installedElems) {
            DrvName drvName(i->name);
            foreach (DrvNames::iterator, j, selectors)
                if (j->matches(drvName)) {
                    printMsg(lvlInfo,
                        format("setting flag on `%1%'") % i->name);
                    setMetaFlag(globals.state, *i, flagName, flagValue);
                    break;
                }
        }

        /* Write the new user environment. */
        if (createUserEnv(globals.state, installedElems,
                globals.profile, globals.keepDerivations, lockToken)) break;
    }
}


static void opSet(Globals & globals,
    Strings args, Strings opFlags, Strings opArgs)
{
    for (Strings::iterator i = opFlags.begin(); i != opFlags.end(); ) {
        string arg = *i++;
        if (parseInstallSourceOptions(globals, i, opFlags, arg)) ;
        else throw UsageError(format("unknown flag `%1%'") % arg);
    }

    DrvInfos elems;
    queryInstSources(globals.state, globals.instSource, opArgs, elems, true);

    if (elems.size() != 1)
        throw Error("--set requires exactly one derivation");
    
    DrvInfo & drv(elems.front());

    if (drv.queryDrvPath(globals.state) != "") {
        PathSet paths = singleton<PathSet>(drv.queryDrvPath(globals.state));
        printMissing(paths);
        if (globals.dryRun) return;
        store->buildDerivations(paths);
    }
    else {
        printMissing(singleton<PathSet>(drv.queryOutPath(globals.state)));
        if (globals.dryRun) return;
        store->ensurePath(drv.queryOutPath(globals.state));
    }

    debug(format("switching to new user environment"));
    Path generation = createGeneration(globals.profile, drv.queryOutPath(globals.state));
    switchLink(globals.profile, generation);
}


static void uninstallDerivations(Globals & globals, Strings & selectors,
    Path & profile)
{
    while (true) {
        string lockToken = optimisticLockProfile(profile);

        DrvInfos installedElems = queryInstalled(globals.state, profile);
        DrvInfos newElems;

        foreach (DrvInfos::iterator, i, installedElems) {
            DrvName drvName(i->name);
            bool found = false;
            foreach (Strings::iterator, j, selectors)
                /* !!! the repeated calls to followLinksToStorePath()
                   are expensive, should pre-compute them. */
                if ((isPath(*j) && i->queryOutPath(globals.state) == followLinksToStorePath(*j))
                    || DrvName(*j).matches(drvName))
                {
                    printMsg(lvlInfo, format("uninstalling `%1%'") % i->name);
                    found = true;
                    break;
                }
            if (!found) newElems.push_back(*i);
        }

        if (globals.dryRun) return;

        if (createUserEnv(globals.state, newElems,
                profile, globals.keepDerivations, lockToken)) break;
    }
}


static void opUninstall(Globals & globals,
    Strings args, Strings opFlags, Strings opArgs)
{
    if (opFlags.size() > 0)
        throw UsageError(format("unknown flag `%1%'") % opFlags.front());
    uninstallDerivations(globals, opArgs, globals.profile);
}


static bool cmpChars(char a, char b)
{
    return toupper(a) < toupper(b);
}


static bool cmpElemByName(const DrvInfo & a, const DrvInfo & b)
{
    return lexicographical_compare(
        a.name.begin(), a.name.end(),
        b.name.begin(), b.name.end(), cmpChars);
}


typedef list<Strings> Table;


void printTable(Table & table)
{
    unsigned int nrColumns = table.size() > 0 ? table.front().size() : 0;
    
    vector<unsigned int> widths;
    widths.resize(nrColumns);
    
    foreach (Table::iterator, i, table) {
        assert(i->size() == nrColumns);
        Strings::iterator j;
        unsigned int column;
        for (j = i->begin(), column = 0; j != i->end(); ++j, ++column)
            if (j->size() > widths[column]) widths[column] = j->size();
    }

    foreach (Table::iterator, i, table) { 
        Strings::iterator j;
        unsigned int column;
        for (j = i->begin(), column = 0; j != i->end(); ++j, ++column) {
            string s = *j;
            replace(s.begin(), s.end(), '\n', ' ');
            cout << s;
            if (column < nrColumns - 1)
                cout << string(widths[column] - s.size() + 2, ' ');
        }
        cout << std::endl;
    }
}


/* This function compares the version of a element against the
   versions in the given set of elements.  `cvLess' means that only
   lower versions are in the set, `cvEqual' means that at most an
   equal version is in the set, and `cvGreater' means that there is at
   least one element with a higher version in the set.  `cvUnavail'
   means that there are no elements with the same name in the set. */

typedef enum { cvLess, cvEqual, cvGreater, cvUnavail } VersionDiff;

static VersionDiff compareVersionAgainstSet(
    const DrvInfo & elem, const DrvInfos & elems, string & version)
{
    DrvName name(elem.name);
    
    VersionDiff diff = cvUnavail;
    version = "?";
    
    for (DrvInfos::const_iterator i = elems.begin(); i != elems.end(); ++i) {
        DrvName name2(i->name);
        if (name.name == name2.name) {
            int d = compareVersions(name.version, name2.version);
            if (d < 0) {
                diff = cvGreater;
                version = name2.version;
            }
            else if (diff != cvGreater && d == 0) {
                diff = cvEqual;
                version = name2.version;
            }
            else if (diff != cvGreater && diff != cvEqual && d > 0) {
                diff = cvLess;
                if (version == "" || compareVersions(version, name2.version) < 0)
                    version = name2.version;
            }
        }
    }

    return diff;
}


static string colorString(const string & s)
{
    if (!isatty(STDOUT_FILENO)) return s;
    return "\e[1;31m" + s + "\e[0m";
}


static void opQuery(Globals & globals,
    Strings args, Strings opFlags, Strings opArgs)
{
    typedef vector< map<string, string> > ResultSet;
    Strings remaining;
    string attrPath;
        
    bool printStatus = false;
    bool printName = true;
    bool printAttrPath = false;
    bool printSystem = false;
    bool printDrvPath = false;
    bool printOutPath = false;
    bool printDescription = false;
    bool printMeta = false;
    bool prebuiltOnly = false;
    bool compareVersions = false;
    bool xmlOutput = false;

    enum { sInstalled, sAvailable } source = sInstalled;

    readOnlyMode = true; /* makes evaluation a bit faster */

    for (Strings::iterator i = args.begin(); i != args.end(); ) {
        string arg = *i++;
        if (arg == "--status" || arg == "-s") printStatus = true;
        else if (arg == "--no-name") printName = false;
        else if (arg == "--system") printSystem = true;
        else if (arg == "--description") printDescription = true;
        else if (arg == "--compare-versions" || arg == "-c") compareVersions = true;
        else if (arg == "--drv-path") printDrvPath = true;
        else if (arg == "--out-path") printOutPath = true;
        else if (arg == "--meta") printMeta = true;
        else if (arg == "--installed") source = sInstalled;
        else if (arg == "--available" || arg == "-a") source = sAvailable;
        else if (arg == "--prebuilt-only" || arg == "-b") prebuiltOnly = true;
        else if (arg == "--xml") xmlOutput = true;
        else if (arg == "--attr-path" || arg == "-P") printAttrPath = true;
        else if (arg == "--attr" || arg == "-A")
            attrPath = needArg(i, args, arg);
        else if (arg[0] == '-')
            throw UsageError(format("unknown flag `%1%'") % arg);
        else remaining.push_back(arg);
    }

    if (remaining.size() == 0)
        printMsg(lvlInfo, "warning: you probably meant to specify the argument '*' to show all packages");

    
    /* Obtain derivation information from the specified source. */
    DrvInfos availElems, installedElems;

    if (source == sInstalled || compareVersions || printStatus)
        installedElems = queryInstalled(globals.state, globals.profile);

    if (source == sAvailable || compareVersions)
        loadDerivations(globals.state, globals.instSource.nixExprPath,
            globals.instSource.systemFilter, globals.instSource.autoArgs,
            attrPath, availElems);

    DrvInfos elems = filterBySelector(globals.state,
        source == sInstalled ? installedElems : availElems,
        remaining, false, prebuiltOnly);
    
    DrvInfos & otherElems(source == sInstalled ? availElems : installedElems);

    
    /* Sort them by name. */
    /* !!! */
    vector<DrvInfo> elems2;
    for (DrvInfos::iterator i = elems.begin(); i != elems.end(); ++i)
        elems2.push_back(*i);
    sort(elems2.begin(), elems2.end(), cmpElemByName);

    
    /* We only need to know the installed paths when we are querying
       the status of the derivation. */
    PathSet installed; /* installed paths */
    
    if (printStatus) {
        for (DrvInfos::iterator i = installedElems.begin();
             i != installedElems.end(); ++i)
            installed.insert(i->queryOutPath(globals.state));
    }

    
    /* Print the desired columns, or XML output. */
    Table table;
    std::ostringstream dummy;
    XMLWriter xml(true, *(xmlOutput ? &cout : &dummy));
    XMLOpenElement xmlRoot(xml, "items");
    
    foreach (vector<DrvInfo>::iterator, i, elems2) {
        try {
            startNest(nest, lvlDebug, format("outputting query result `%1%'") % i->attrPath);

            /* For table output. */
            Strings columns;

            /* For XML output. */
            XMLAttrs attrs;

            if (printStatus) {
                bool hasSubs = store->hasSubstitutes(i->queryOutPath(globals.state));
                bool isInstalled = installed.find(i->queryOutPath(globals.state)) != installed.end();
                bool isValid = store->isValidPath(i->queryOutPath(globals.state));
                if (xmlOutput) {
                    attrs["installed"] = isInstalled ? "1" : "0";
                    attrs["valid"] = isValid ? "1" : "0";
                    attrs["substitutable"] = hasSubs ? "1" : "0";
                } else
                    columns.push_back(
                        (string) (isInstalled ? "I" : "-")
                        + (isValid ? "P" : "-")
                        + (hasSubs ? "S" : "-"));
            }

            if (xmlOutput)
                attrs["attrPath"] = i->attrPath;
            else if (printAttrPath)
                columns.push_back(i->attrPath);

            if (xmlOutput)
                attrs["name"] = i->name;
            else if (printName)
                columns.push_back(i->name);

            if (compareVersions) {
                /* Compare this element against the versions of the
                   same named packages in either the set of available
                   elements, or the set of installed elements.  !!!
                   This is O(N * M), should be O(N * lg M). */
                string version;
                VersionDiff diff = compareVersionAgainstSet(*i, otherElems, version);

                char ch;
                switch (diff) {
                    case cvLess: ch = '>'; break;
                    case cvEqual: ch = '='; break;
                    case cvGreater: ch = '<'; break;
                    case cvUnavail: ch = '-'; break;
                    default: abort();
                }

                if (xmlOutput) {
                    if (diff != cvUnavail) {
                        attrs["versionDiff"] = ch;
                        attrs["maxComparedVersion"] = version;
                    }
                } else {
                    string column = (string) "" + ch + " " + version;
                    if (diff == cvGreater) column = colorString(column);
                    columns.push_back(column);
                }
            }

            if (xmlOutput) {
                if (i->system != "") attrs["system"] = i->system;
            }
            else if (printSystem) 
                columns.push_back(i->system);

            if (printDrvPath) {
                string drvPath = i->queryDrvPath(globals.state);
                if (xmlOutput) {
                    if (drvPath != "") attrs["drvPath"] = drvPath;
                } else
                    columns.push_back(drvPath == "" ? "-" : drvPath);
            }
        
            if (printOutPath) {
                string outPath = i->queryOutPath(globals.state);
                if (xmlOutput) {
                    if (outPath != "") attrs["outPath"] = outPath;
                } else
                    columns.push_back(outPath);
            }

            if (printDescription) {
                MetaInfo meta = i->queryMetaInfo(globals.state);
                MetaValue value = meta["description"];
                string descr = value.type == MetaValue::tpString ? value.stringValue : "";
                if (xmlOutput) {
                    if (descr != "") attrs["description"] = descr;
                } else
                    columns.push_back(descr);
            }

            if (xmlOutput)
                if (printMeta) {
                    XMLOpenElement item(xml, "item", attrs);
                    MetaInfo meta = i->queryMetaInfo(globals.state);
                    for (MetaInfo::iterator j = meta.begin(); j != meta.end(); ++j) {
                        XMLAttrs attrs2;
                        attrs2["name"] = j->first;
                        if (j->second.type == MetaValue::tpString) {
                            attrs2["type"] = "string";
                            attrs2["value"] = j->second.stringValue;
                            xml.writeEmptyElement("meta", attrs2);
                        } else if (j->second.type == MetaValue::tpInt) {
                            attrs2["type"] = "int";
                            attrs2["value"] = (format("%1%") % j->second.intValue).str();
                            xml.writeEmptyElement("meta", attrs2);
                        } else if (j->second.type == MetaValue::tpStrings) {
                            attrs2["type"] = "strings";
                            XMLOpenElement m(xml, "meta", attrs2);
                            foreach (Strings::iterator, k, j->second.stringValues) { 
                                XMLAttrs attrs3;
                                attrs3["value"] = *k;
                                xml.writeEmptyElement("string", attrs3);
                           }
                        }
                    }
                }
                else
                    xml.writeEmptyElement("item", attrs);
            else
                table.push_back(columns);

            cout.flush();

        } catch (AssertionError & e) {
            printMsg(lvlTalkative, format("skipping derivation named `%1%' which gives an assertion failure") % i->name);
        }
    }

    if (!xmlOutput) printTable(table);
}


static void opSwitchProfile(Globals & globals,
    Strings args, Strings opFlags, Strings opArgs)
{
    if (opFlags.size() > 0)
        throw UsageError(format("unknown flag `%1%'") % opFlags.front());
    if (opArgs.size() != 1)
        throw UsageError(format("exactly one argument expected"));

    Path profile = absPath(opArgs.front());
    Path profileLink = getHomeDir() + "/.nix-profile";

    switchLink(profileLink, profile);
}


static const int prevGen = -2;


static void switchGeneration(Globals & globals, int dstGen)
{
    PathLocks lock;
    lockProfile(lock, globals.profile);
    
    int curGen;
    Generations gens = findGenerations(globals.profile, curGen);

    Generation dst;
    for (Generations::iterator i = gens.begin(); i != gens.end(); ++i)
        if ((dstGen == prevGen && i->number < curGen) ||
            (dstGen >= 0 && i->number == dstGen))
            dst = *i;

    if (!dst) {
        if (dstGen == prevGen)
            throw Error(format("no generation older than the current (%1%) exists")
                % curGen);
        else
            throw Error(format("generation %1% does not exist") % dstGen);
    }

    printMsg(lvlInfo, format("switching from generation %1% to %2%")
        % curGen % dst.number);
    
    if (globals.dryRun) return;
    
    switchLink(globals.profile, dst.path);
}


static void opSwitchGeneration(Globals & globals,
    Strings args, Strings opFlags, Strings opArgs)
{
    if (opFlags.size() > 0)
        throw UsageError(format("unknown flag `%1%'") % opFlags.front());
    if (opArgs.size() != 1)
        throw UsageError(format("exactly one argument expected"));

    int dstGen;
    if (!string2Int(opArgs.front(), dstGen))
        throw UsageError(format("expected a generation number"));

    switchGeneration(globals, dstGen);
}


static void opRollback(Globals & globals,
    Strings args, Strings opFlags, Strings opArgs)
{
    if (opFlags.size() > 0)
        throw UsageError(format("unknown flag `%1%'") % opFlags.front());
    if (opArgs.size() != 0)
        throw UsageError(format("no arguments expected"));

    switchGeneration(globals, prevGen);
}


static void opListGenerations(Globals & globals,
    Strings args, Strings opFlags, Strings opArgs)
{
    if (opFlags.size() > 0)
        throw UsageError(format("unknown flag `%1%'") % opFlags.front());
    if (opArgs.size() != 0)
        throw UsageError(format("no arguments expected"));

    PathLocks lock;
    lockProfile(lock, globals.profile);
    
    int curGen;
    Generations gens = findGenerations(globals.profile, curGen);

    for (Generations::iterator i = gens.begin(); i != gens.end(); ++i) {
        tm t;
        if (!localtime_r(&i->creationTime, &t)) throw Error("cannot convert time");
        cout << format("%|4|   %|4|-%|02|-%|02| %|02|:%|02|:%|02|   %||\n")
            % i->number
            % (t.tm_year + 1900) % (t.tm_mon + 1) % t.tm_mday
            % t.tm_hour % t.tm_min % t.tm_sec
            % (i->number == curGen ? "(current)" : "");
    }
}


static void deleteGeneration2(const Path & profile, unsigned int gen)
{
    printMsg(lvlInfo, format("removing generation %1%") % gen);
    deleteGeneration(profile, gen);
}


static void opDeleteGenerations(Globals & globals,
    Strings args, Strings opFlags, Strings opArgs)
{
    if (opFlags.size() > 0)
        throw UsageError(format("unknown flag `%1%'") % opFlags.front());

    PathLocks lock;
    lockProfile(lock, globals.profile);
    
    int curGen;
    Generations gens = findGenerations(globals.profile, curGen);

    for (Strings::iterator i = opArgs.begin(); i != opArgs.end(); ++i) {

        if (*i == "old") {
            for (Generations::iterator j = gens.begin(); j != gens.end(); ++j)
                if (j->number != curGen)
                    deleteGeneration2(globals.profile, j->number);
        }

        else {
            int n;
            if (!string2Int(*i, n) || n < 0)
                throw UsageError(format("invalid generation specifier `%1%'")  % *i);
            bool found = false;
            for (Generations::iterator j = gens.begin(); j != gens.end(); ++j) {
                if (j->number == n) {
                    deleteGeneration2(globals.profile, j->number);
                    found = true;
                    break;
                }
            }
            if (!found)
                printMsg(lvlError, format("generation %1% does not exist") % n);
        }
    }
}


void run(Strings args)
{
    Strings opFlags, opArgs, remaining;
    Operation op = 0;
    
    Globals globals;
    
    globals.instSource.type = srcUnknown;
    globals.instSource.nixExprPath = getDefNixExprPath();
    globals.instSource.systemFilter = thisSystem;
    
    globals.dryRun = false;
    globals.preserveInstalled = false;

    globals.keepDerivations =
        queryBoolSetting("env-keep-derivations", false);
    
    for (Strings::iterator i = args.begin(); i != args.end(); ) {
        string arg = *i++;

        Operation oldOp = op;

        if (arg == "--install" || arg == "-i")
            op = opInstall;
        else if (parseOptionArg(arg, i, args.end(),
                     globals.state, globals.instSource.autoArgs))
            ;
        else if (arg == "--force-name") // undocumented flag for nix-install-package
            globals.forceName = needArg(i, args, arg);
        else if (arg == "--uninstall" || arg == "-e")
            op = opUninstall;
        else if (arg == "--upgrade" || arg == "-u")
            op = opUpgrade;
        else if (arg == "--set-flag")
            op = opSetFlag;
        else if (arg == "--set")
            op = opSet;
        else if (arg == "--query" || arg == "-q")
            op = opQuery;
        else if (arg == "--profile" || arg == "-p")
            globals.profile = absPath(needArg(i, args, arg));
        else if (arg == "--file" || arg == "-f")
            globals.instSource.nixExprPath = absPath(needArg(i, args, arg));
        else if (arg == "--switch-profile" || arg == "-S")
            op = opSwitchProfile;
        else if (arg == "--switch-generation" || arg == "-G")
            op = opSwitchGeneration;
        else if (arg == "--rollback")
            op = opRollback;
        else if (arg == "--list-generations")
            op = opListGenerations;
        else if (arg == "--delete-generations")
            op = opDeleteGenerations;
        else if (arg == "--dry-run") {
            printMsg(lvlInfo, "(dry run; not doing anything)");
            globals.dryRun = true;
        }
        else if (arg == "--system-filter")
            globals.instSource.systemFilter = needArg(i, args, arg);
        else {
            remaining.push_back(arg);
            if (arg[0] == '-') {
                opFlags.push_back(arg);
                if (arg == "--from-profile") { /* !!! hack */
                    if (i != args.end()) opFlags.push_back(*i++);
                }
            } else opArgs.push_back(arg);
        }

        if (oldOp && oldOp != op)
            throw UsageError("only one operation may be specified");
    }

    if (!op) throw UsageError("no operation specified");

    if (globals.profile == "") {
        Path profileLink = getHomeDir() + "/.nix-profile";
        globals.profile = pathExists(profileLink)
            ? absPath(readLink(profileLink), dirOf(profileLink))
            : canonPath(nixStateDir + "/profiles/default");
    }
    
    store = openStore();

    op(globals, remaining, opFlags, opArgs);

    globals.state.printStats();
}


string programId = "nix-env";