File: variables.c

package info (click to toggle)
bash 2.05a-11
  • links: PTS
  • area: main
  • in suites: woody
  • size: 9,804 kB
  • ctags: 6,165
  • sloc: ansic: 67,305; sh: 10,832; perl: 4,105; yacc: 3,166; makefile: 3,075; asm: 48; awk: 23
file content (3295 lines) | stat: -rw-r--r-- 80,883 bytes parent folder | download
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
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
/* variables.c -- Functions for hacking shell variables. */

/* Copyright (C) 1987,1989 Free Software Foundation, Inc.

   This file is part of GNU Bash, the Bourne Again SHell.

   Bash is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   Bash is distributed in the hope that it will be useful, but WITHOUT
   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
   License for more details.

   You should have received a copy of the GNU General Public License
   along with Bash; see the file COPYING.  If not, write to the Free
   Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. */

#include "config.h"

#include "bashtypes.h"
#include "posixstat.h"
#include "posixtime.h"

#if defined (qnx)
#  include <sys/vc.h>
#endif

#if defined (HAVE_UNISTD_H)
#  include <unistd.h>
#endif

#include <stdio.h>
#include "chartypes.h"
#include <pwd.h>
#include "bashansi.h"

#include "shell.h"
#include "flags.h"
#include "execute_cmd.h"
#include "findcmd.h"
#include "mailcheck.h"
#include "input.h"
#include "hashcmd.h"
#include "pathexp.h"

#include "builtins/getopt.h"
#include "builtins/common.h"

#if defined (READLINE)
#  include "bashline.h"
#  include <readline/readline.h>
#else
#  include <tilde/tilde.h>
#endif

#if defined (HISTORY)
#  include "bashhist.h"
#  include <readline/history.h>
#endif /* HISTORY */

#if defined (PROGRAMMABLE_COMPLETION)
#  include "pcomplete.h"
#endif

/* Variables used here and defined in other files. */
extern int posixly_correct;
extern int line_number;
extern int subshell_environment, indirection_level;
extern int build_version, patch_level;
extern char *dist_version, *release_status;
extern char *shell_name;
extern char *primary_prompt, *secondary_prompt;
extern char *current_host_name;
extern sh_builtin_func_t *this_shell_builtin;
extern SHELL_VAR *this_shell_function;
extern char *this_command_name;
extern time_t shell_start_time;

/* The list of shell variables that the user has created, or that came from
   the environment. */
HASH_TABLE *shell_variables = (HASH_TABLE *)NULL;

/* The list of shell functions that the user has created, or that came from
   the environment. */
HASH_TABLE *shell_functions = (HASH_TABLE *)NULL;

/* The current variable context.  This is really a count of how deep into
   executing functions we are. */
int variable_context = 0;

/* The array of shell assignments which are made only in the environment
   for a single command. */
char **temporary_env = (char **)NULL;

/* The array of shell assignments which are in the environment for the
   execution of a shell function. */
char **function_env = (char **)NULL;

/* The array of shell assignments which are made only in the environment
   for the execution of a shell builtin command which may cause more than
   one command to be executed (e.g., "eval" or "source"). */
char **builtin_env = (char **)NULL;

/* Some funky variables which are known about specially.  Here is where
   "$*", "$1", and all the cruft is kept. */
char *dollar_vars[10];
WORD_LIST *rest_of_args = (WORD_LIST *)NULL;

/* The value of $$. */
pid_t dollar_dollar_pid;

/* An array which is passed to commands as their environment.  It is
   manufactured from the union of the initial environment and the
   shell variables that are marked for export. */
char **export_env = (char **)NULL;
static int export_env_index;
static int export_env_size;

/* Non-zero means that we have to remake EXPORT_ENV. */
int array_needs_making = 1;

/* The number of times BASH has been executed.  This is set
   by initialize_variables (). */
int shell_level = 0;

static char *have_local_variables;
static int local_variable_stack_size;

/* Some forward declarations. */
static void set_machine_vars __P((void));
static void set_home_var __P((void));
static void set_shell_var __P((void));
static char *get_bash_name __P((void));
static void initialize_shell_level __P((void));
static void uidset __P((void));
#if defined (ARRAY_VARS)
static void make_vers_array __P((void));
#endif
static void initialize_dynamic_variables __P((void));

static void sbrand __P((unsigned long));		/* set bash random number generator. */

static int qsort_var_comp __P((SHELL_VAR **, SHELL_VAR **));
static SHELL_VAR **all_vars __P((HASH_TABLE *));

static void free_variable_hash_data __P((PTR_T));
static SHELL_VAR *new_shell_variable __P((const char *));

static SHELL_VAR *make_new_variable __P((const char *));

static int visible_var __P((SHELL_VAR *));
static SHELL_VAR **_visible_names __P((HASH_TABLE *));
static int visible_and_exported __P((SHELL_VAR *));
#if defined (ARRAY_VARS)
static int visible_array_vars __P((SHELL_VAR *));
#endif

static inline char *mk_env_string __P((const char *, const char *));
static SHELL_VAR *shell_var_from_env_string __P((const char *, char *, int));
static SHELL_VAR *bind_name_in_env_array __P((const char *, char *, char **));
static SHELL_VAR *find_name_in_env_array __P((const char *, char **));

static SHELL_VAR *bind_tempenv_variable __P((const char *, char *));
static void dispose_temporary_vars __P((char ***));
static void merge_env_array __P((char **));

/* Make VAR be auto-exported.  VAR is a pointer to a SHELL_VAR. */
#define set_auto_export(var) \
  do { var->attributes |= att_exported; array_needs_making = 1; } while (0)

/* Initialize the shell variables from the current environment.
   If PRIVMODE is nonzero, don't import functions from ENV or
   parse $SHELLOPTS. */
void
initialize_shell_variables (env, privmode)
     char **env;
     int privmode;
{
  char *name, *string, *temp_string;
  int c, char_index, string_index, string_length;
  SHELL_VAR *temp_var;

  if (shell_variables == 0)
    shell_variables = make_hash_table (0);

  if (shell_functions == 0)
    shell_functions = make_hash_table (0);

  for (string_index = 0; string = env[string_index++]; )
    {
      char_index = 0;
      name = string;
      while ((c = *string++) && c != '=')
	;
      if (string[-1] == '=')
	char_index = string - name - 1;

      /* If there are weird things in the environment, like `=xxx' or a
	 string without an `=', just skip them. */
      if (char_index == 0)
	continue;

      /* ASSERT(name[char_index] == '=') */
      name[char_index] = '\0';
      /* Now, name = env variable name, string = env variable value, and
	 char_index == strlen (name) */

      /* If exported function, define it now.  Don't import functions from
         the environment in privileged mode. */
      if (privmode == 0 && read_but_dont_execute == 0 && STREQN ("() {", string, 4))
	{
	  string_length = strlen (string);
	  temp_string = (char *)xmalloc (3 + string_length + char_index);

	  strcpy (temp_string, name);
	  temp_string[char_index] = ' ';
	  strcpy (temp_string + char_index + 1, string);

	  parse_and_execute (temp_string, name, SEVAL_NONINT|SEVAL_NOHIST);

	  /* Ancient backwards compatibility.  Old versions of bash exported
	     functions like name()=() {...} */
	  if (name[char_index - 1] == ')' && name[char_index - 2] == '(')
	    name[char_index - 2] = '\0';

	  if (temp_var = find_function (name))
	    {
	      VSETATTR (temp_var, (att_exported|att_imported));
	      array_needs_making = 1;
	    }
	  else
	    report_error ("error importing function definition for `%s'", name);

	  /* ( */
	  if (name[char_index - 1] == ')' && name[char_index - 2] == '\0')
	    name[char_index - 2] = '(';		/* ) */
	}
#if defined (ARRAY_VARS)
#  if 0
      /* Array variables may not yet be exported. */
      else if (*string == '(' && string[1] == '[' && strchr (string, ')'))
	{
	  string_length = 1;
	  temp_string = extract_array_assignment_list (string, &string_length);
	  temp_var = assign_array_from_string (name, temp_string);
	  FREE (temp_string);
	  VSETATTR (temp_var, (att_exported | att_imported));
	  array_needs_making = 1;
	}
#  endif
#endif
      else
	{
	  temp_var = bind_variable (name, string);
	  VSETATTR (temp_var, (att_exported | att_imported));
	  array_needs_making = 1;
	}

      name[char_index] = '=';
      /* temp_var can be NULL if it was an exported function with a syntax
	 error (a different bug, but it still shouldn't dump core). */
      if (temp_var && function_p (temp_var) == 0)	/* XXX not yet */
	{
	  CACHE_IMPORTSTR (temp_var, name);
	}
    }

  set_pwd ();

  /* Set up initial value of $_ */
  temp_var = bind_variable ("_", dollar_vars[0]);

  /* Remember this pid. */
  dollar_dollar_pid = getpid ();

  /* Now make our own defaults in case the vars that we think are
     important are missing. */
  temp_var = set_if_not ("PATH", DEFAULT_PATH_VALUE);
#if 0
  set_auto_export (temp_var);	/* XXX */
#endif

  temp_var = set_if_not ("TERM", "dumb");
#if 0
  set_auto_export (temp_var);	/* XXX */
#endif

#if defined (qnx)
  /* set node id -- don't import it from the environment */
  {
    char node_name[22];
    qnx_nidtostr (getnid (), node_name, sizeof (node_name));
    temp_var = bind_variable ("NODE", node_name);
    set_auto_export (temp_var);
  }
#endif

  /* set up the prompts. */
  if (interactive_shell)
    {
#if defined (PROMPT_STRING_DECODE)
      set_if_not ("PS1", primary_prompt);
#else
      if (current_user.uid == -1)
	get_current_user_info ();
      set_if_not ("PS1", current_user.euid == 0 ? "# " : primary_prompt);
#endif
      set_if_not ("PS2", secondary_prompt);
    }
  set_if_not ("PS4", "+ ");

  /* Don't allow IFS to be imported from the environment. */
  temp_var = bind_variable ("IFS", " \t\n");

  /* Magic machine types.  Pretty convenient. */
  set_machine_vars ();

  /* Default MAILCHECK for interactive shells.  Defer the creation of a
     default MAILPATH until the startup files are read, because MAIL
     names a mail file if MAILPATH is not set, and we should provide a
     default only if neither is set. */
  if (interactive_shell)
    set_if_not ("MAILCHECK", posixly_correct ? "600" : "60");

  /* Do some things with shell level. */
  initialize_shell_level ();

  set_ppid ();

  /* Initialize the `getopts' stuff. */
  bind_variable ("OPTIND", "1");
  getopts_reset (0);
  bind_variable ("OPTERR", "1");
  sh_opterr = 1;

  if (login_shell == 1)
    set_home_var ();

  /* Get the full pathname to THIS shell, and set the BASH variable
     to it. */
  name = get_bash_name ();
  temp_var = bind_variable ("BASH", name);
  free (name);

  /* Make the exported environment variable SHELL be the user's login
     shell.  Note that the `tset' command looks at this variable
     to determine what style of commands to output; if it ends in "csh",
     then C-shell commands are output, else Bourne shell commands. */
  set_shell_var ();

  /* Make a variable called BASH_VERSION which contains the version info. */
  bind_variable ("BASH_VERSION", shell_version_string ());
#if defined (ARRAY_VARS)
  make_vers_array ();
#endif

  /* Find out if we're supposed to be in Posix.2 mode via an
     environment variable. */
  temp_var = find_variable ("POSIXLY_CORRECT");
  if (!temp_var)
    temp_var = find_variable ("POSIX_PEDANTIC");
  if (temp_var && imported_p (temp_var))
    sv_strict_posix (temp_var->name);

#if defined (HISTORY)
  /* Set history variables to defaults, and then do whatever we would
     do if the variable had just been set.  Do this only in the case
     that we are remembering commands on the history list. */
  if (remember_on_history)
    {
      name = bash_tilde_expand (posixly_correct ? "~/.sh_history" : "~/.bash_history");

      set_if_not ("HISTFILE", name);
      free (name);

      set_if_not ("HISTSIZE", "500");
      sv_histsize ("HISTSIZE");
    }
#endif /* HISTORY */

  /* Seed the random number generator. */
  sbrand (dollar_dollar_pid + shell_start_time);

  /* Handle some "special" variables that we may have inherited from a
     parent shell. */
  if (interactive_shell)
    {
      temp_var = find_variable ("IGNOREEOF");
      if (!temp_var)
	temp_var = find_variable ("ignoreeof");
      if (temp_var && imported_p (temp_var))
	sv_ignoreeof (temp_var->name);
    }

#if defined (HISTORY)
  if (interactive_shell && remember_on_history)
    {
      sv_history_control ("HISTCONTROL");
      sv_histignore ("HISTIGNORE");
    }
#endif /* HISTORY */

     /*
      * 24 October 2001
      *
      * I'm tired of the arguing and bug reports.  Bash now leaves SSH_CLIENT
      * and SSH2_CLIENT alone.  I'm going to rely on the shell_level check in
      * isnetconn() to avoid running the startup files more often than wanted.
      * That will, of course, only work if the user's login shell is bash, so
      * I've made that behavior conditional on SSH_SOURCE_BASHRC being defined
      * in config-top.h.
      */
#if 0
  temp_var = find_variable ("SSH_CLIENT");
  if (temp_var && imported_p (temp_var))
    {
      VUNSETATTR (temp_var, att_exported);
      array_needs_making = 1;
    }
  temp_var = find_variable ("SSH2_CLIENT");
  if (temp_var && imported_p (temp_var))
    {
      VUNSETATTR (temp_var, att_exported);
      array_needs_making = 1;
    }
#endif

  /* Get the user's real and effective user ids. */
  uidset ();

  /* Initialize the dynamic variables, and seed their values. */
  initialize_dynamic_variables ();
}

static void
set_machine_vars ()
{
  SHELL_VAR *temp_var;

  temp_var = set_if_not ("HOSTTYPE", HOSTTYPE);
  temp_var = set_if_not ("OSTYPE", OSTYPE);
  temp_var = set_if_not ("MACHTYPE", MACHTYPE);

  temp_var = set_if_not ("HOSTNAME", current_host_name);
}

/* Set $HOME to the information in the password file if we didn't get
   it from the environment. */

/* This function is not static so the tilde and readline libraries can
   use it. */
char *
sh_get_home_dir ()
{
  if (current_user.home_dir == 0)
    get_current_user_info ();
  return current_user.home_dir;
}

static void
set_home_var ()
{
  SHELL_VAR *temp_var;

  temp_var = find_variable ("HOME");
  if (temp_var == 0)
    temp_var = bind_variable ("HOME", sh_get_home_dir ());
#if 0
  VSETATTR (temp_var, att_exported);
#endif
}

/* Set $SHELL to the user's login shell if it is not already set.  Call
   get_current_user_info if we haven't already fetched the shell. */
static void
set_shell_var ()
{
  SHELL_VAR *temp_var;

  temp_var = find_variable ("SHELL");
  if (temp_var == 0)
    {
      if (current_user.shell == 0)
	get_current_user_info ();
      temp_var = bind_variable ("SHELL", current_user.shell);
    }
#if 0
  VSETATTR (temp_var, att_exported);
#endif
}

static char *
get_bash_name ()
{
  char *name;

  if ((login_shell == 1) && RELPATH(shell_name))
    {
      if (current_user.shell == 0)
	get_current_user_info ();
      name = savestring (current_user.shell);
    }
  else if (ABSPATH(shell_name))
    name = savestring (shell_name);
  else if (shell_name[0] == '.' && shell_name[1] == '/')
    {
      /* Fast path for common case. */
      char *cdir;
      int len;

      cdir = get_string_value ("PWD");
      if (cdir)
	{
	  len = strlen (cdir);
	  name = (char *)xmalloc (len + strlen (shell_name) + 1);
	  strcpy (name, cdir);
	  strcpy (name + len, shell_name + 1);
	}
      else
	name = savestring (shell_name);
    }
  else
    {
      char *tname;
      int s;

      tname = find_user_command (shell_name);

      if (tname == 0)
	{
	  /* Try the current directory.  If there is not an executable
	     there, just punt and use the login shell. */
	  s = file_status (shell_name);
	  if (s & FS_EXECABLE)
	    {
	      tname = make_absolute (shell_name, get_string_value ("PWD"));
	      if (*shell_name == '.')
		{
		  name = sh_canonpath (tname, PATH_CHECKDOTDOT|PATH_CHECKEXISTS);
		  if (name == 0)
		    name = tname;
		  else
		    free (tname);
		}
	     else
		name = tname;
	    }
	  else
	    {
	      if (current_user.shell == 0)
		get_current_user_info ();
	      name = savestring (current_user.shell);
	    }
	}
      else
	{
	  name = full_pathname (tname);
	  free (tname);
	}
    }

  return (name);
}

void
adjust_shell_level (change)
     int change;
{
  char new_level[5], *old_SHLVL;
  long old_level;
  SHELL_VAR *temp_var;

  old_SHLVL = get_string_value ("SHLVL");
  if (old_SHLVL == 0 || *old_SHLVL == '\0' || legal_number (old_SHLVL, &old_level) == 0)
    old_level = 0;

  shell_level = old_level + change;
  if (shell_level < 0)
    shell_level = 0;
  else if (shell_level > 1000)
    {
      internal_warning ("shell level (%d) too high, resetting to 1", shell_level);
      shell_level = 1;
    }

  /* We don't need the full generality of itos here. */
  if (shell_level < 10)
    {
      new_level[0] = shell_level + '0';
      new_level[1] = '\0';
    }
  else if (shell_level < 100)
    {
      new_level[0] = (shell_level / 10) + '0';
      new_level[1] = (shell_level % 10) + '0';
      new_level[2] = '\0';
    }
  else if (shell_level < 1000)
    {
      new_level[0] = (shell_level / 100) + '0';
      old_level = shell_level % 100;
      new_level[1] = (old_level / 10) + '0';
      new_level[2] = (old_level % 10) + '0';
      new_level[3] = '\0';
    }

  temp_var = bind_variable ("SHLVL", new_level);
  set_auto_export (temp_var);
}

static void
initialize_shell_level ()
{
  adjust_shell_level (1);
}

/* If we got PWD from the environment, update our idea of the current
   working directory.  In any case, make sure that PWD exists before
   checking it.  It is possible for getcwd () to fail on shell startup,
   and in that case, PWD would be undefined.  If this is an interactive
   login shell, see if $HOME is the current working directory, and if
   that's not the same string as $PWD, set PWD=$HOME. */

void
set_pwd ()
{
  SHELL_VAR *temp_var, *home_var;
  char *temp_string, *home_string;

  home_var = find_variable ("HOME");
  home_string = home_var ? value_cell (home_var) : (char *)NULL;

  temp_var = find_variable ("PWD");
  if (temp_var && imported_p (temp_var) &&
      (temp_string = value_cell (temp_var)) &&
      same_file (temp_string, ".", (struct stat *)NULL, (struct stat *)NULL))
    set_working_directory (temp_string);
  else if (home_string && interactive_shell && login_shell &&
	   same_file (home_string, ".", (struct stat *)NULL, (struct stat *)NULL))
    {
      set_working_directory (home_string);
      temp_var = bind_variable ("PWD", home_string);
      set_auto_export (temp_var);
    }
  else
    {
      temp_string = get_working_directory ("shell-init");
      if (temp_string)
	{
	  temp_var = bind_variable ("PWD", temp_string);
	  set_auto_export (temp_var);
	  free (temp_string);
	}
    }

  /* According to the Single Unix Specification, v2, $OLDPWD is an
     `environment variable' and therefore should be auto-exported.
     Make a dummy invisible variable for OLDPWD, and mark it as exported. */
  temp_var = bind_variable ("OLDPWD", (char *)NULL);
  VSETATTR (temp_var, (att_exported | att_invisible));
}

/* Make a variable $PPID, which holds the pid of the shell's parent.  */
void
set_ppid ()
{
  char namebuf[INT_STRLEN_BOUND(pid_t) + 1], *name;
  SHELL_VAR *temp_var;

  name = inttostr (getppid (), namebuf, sizeof(namebuf));
  temp_var = find_variable ("PPID");
  if (temp_var)
    VUNSETATTR (temp_var, (att_readonly | att_exported));
  temp_var = bind_variable ("PPID", name);
  VSETATTR (temp_var, (att_readonly | att_integer));
}

static void
uidset ()
{
  char buff[INT_STRLEN_BOUND(uid_t) + 1], *b;
  register SHELL_VAR *v;

  b = inttostr (current_user.uid, buff, sizeof (buff));
  v = find_variable ("UID");
  if (v == 0)
    {
      v = bind_variable ("UID", b);
      VSETATTR (v, (att_readonly | att_integer));
    }

  if (current_user.euid != current_user.uid)
    b = inttostr (current_user.euid, buff, sizeof (buff));

  v = find_variable ("EUID");
  if (v == 0)
    {
      v = bind_variable ("EUID", b);
      VSETATTR (v, (att_readonly | att_integer));
    }
}

#if defined (ARRAY_VARS)
static void
make_vers_array ()
{
  SHELL_VAR *vv;
  ARRAY *av;
  char *s, d[32], b[INT_STRLEN_BOUND(int) + 1];

  makunbound ("BASH_VERSINFO", shell_variables);

  vv = make_new_array_variable ("BASH_VERSINFO");
  av = array_cell (vv);
  strcpy (d, dist_version);
  s = strchr (d, '.');
  if (s)
    *s++ = '\0';
  array_add_element (av, 0, d);
  array_add_element (av, 1, s);
  s = inttostr (patch_level, b, sizeof (b));
  array_add_element (av, 2, s);
  s = inttostr (build_version, b, sizeof (b));
  array_add_element (av, 3, s);
  array_add_element (av, 4, release_status);
  array_add_element (av, 5, MACHTYPE);

  VSETATTR (vv, att_readonly);
}
#endif /* ARRAY_VARS */

/* Set the environment variables $LINES and $COLUMNS in response to
   a window size change. */
void
sh_set_lines_and_columns (lines, cols)
     int lines, cols;
{
  char val[INT_STRLEN_BOUND(int) + 1], *v;

  v = inttostr (lines, val, sizeof (val));
  bind_variable ("LINES", v);

  v = inttostr (cols, val, sizeof (val));
  bind_variable ("COLUMNS", v);
}

/* Set NAME to VALUE if NAME has no value. */
SHELL_VAR *
set_if_not (name, value)
     char *name, *value;
{
  SHELL_VAR *v;

  v = find_variable (name);
  if (v == 0)
    v = bind_variable (name, value);
  return (v);
}

/* Map FUNCTION over the variables in VARIABLES.  Return an array of the
   variables for which FUNCTION returns a non-zero value.  A NULL value
   for FUNCTION means to use all variables. */
SHELL_VAR **
map_over (function, var_hash_table)
     sh_var_map_func_t *function;
     HASH_TABLE *var_hash_table;
{
  register int i;
  register BUCKET_CONTENTS *tlist;
  SHELL_VAR *var, **list;
  int list_index, list_size;

  list = (SHELL_VAR **)NULL;
  for (i = list_index = list_size = 0; i < var_hash_table->nbuckets; i++)
    {
      tlist = get_hash_bucket (i, var_hash_table);

      while (tlist)
	{
	  var = (SHELL_VAR *)tlist->data;

	  if (!function || (*function) (var))
	    {
	      if (list_index + 1 >= list_size)
		list = (SHELL_VAR **)
		  xrealloc (list, (list_size += 20) * sizeof (SHELL_VAR *));

	      list[list_index++] = var;
	      list[list_index] = (SHELL_VAR *)NULL;
	    }
	  tlist = tlist->next;
	}
    }
  return (list);
}

void
sort_variables (array)
     SHELL_VAR **array;
{
  qsort (array, array_len ((char **)array), sizeof (SHELL_VAR *), (QSFUNC *)qsort_var_comp);
}

static int
qsort_var_comp (var1, var2)
     SHELL_VAR **var1, **var2;
{
  int result;

  if ((result = (*var1)->name[0] - (*var2)->name[0]) == 0)
    result = strcmp ((*var1)->name, (*var2)->name);

  return (result);
}

/* Create a NULL terminated array of all the shell variables in TABLE. */
static SHELL_VAR **
all_vars (table)
     HASH_TABLE *table;
{
  SHELL_VAR **list;

  list = map_over ((sh_var_map_func_t *)NULL, table);
  if (list /* && posixly_correct */)
    sort_variables (list);
  return (list);
}

/* Create a NULL terminated array of all the shell variables. */
SHELL_VAR **
all_shell_variables ()
{
  return (all_vars (shell_variables));
}

/* Create a NULL terminated array of all the shell functions. */
SHELL_VAR **
all_shell_functions ()
{
  return (all_vars (shell_functions));
}

/* Print LIST (a list of shell variables) to stdout in such a way that
   they can be read back in. */
void
print_var_list (list)
     register SHELL_VAR **list;
{
  register int i;
  register SHELL_VAR *var;

  for (i = 0; list && (var = list[i]); i++)
    if (!invisible_p (var))
      print_assignment (var);
}

/* Print LIST (a list of shell functions) to stdout in such a way that
   they can be read back in. */
void
print_func_list (list)
     register SHELL_VAR **list;
{
  register int i;
  register SHELL_VAR *var;

  for (i = 0; list && (var = list[i]); i++)
    {
      printf ("%s ", var->name);
      print_var_function (var);
      printf ("\n");
    }
}
      
#if defined (NOTDEF)
/* Print LIST (a linked list of shell variables) to stdout
   by printing the names, without the values.  Used to support the
   `set +' command. */
void
print_vars_no_values (list)
     register SHELL_VAR **list;
{
  register int i;
  register SHELL_VAR *var;

  for (i = 0; list && (var = list[i]); i++)
    if (!invisible_p (var))
      printf ("%s\n", var->name);
}
#endif

/* Print the value of a single SHELL_VAR.  No newline is
   output, but the variable is printed in such a way that
   it can be read back in. */
void
print_assignment (var)
     SHELL_VAR *var;
{
  if (function_p (var) && var->value)
    {
      printf ("%s", var->name);
      print_var_function (var);
      printf ("\n");
    }
#if defined (ARRAY_VARS)
  else if (array_p (var) && var->value)
    print_array_assignment (var, 0);
#endif /* ARRAY_VARS */
  else if (var->value)
    {
      printf ("%s=", var->name);
      print_var_value (var, 1);
      printf ("\n");
    }
}

/* Print the value cell of VAR, a shell variable.  Do not print
   the name, nor leading/trailing newline.  If QUOTE is non-zero,
   and the value contains shell metacharacters, quote the value
   in such a way that it can be read back in. */
void
print_var_value (var, quote)
     SHELL_VAR *var;
     int quote;
{
  char *t;

  if (var->value)
    {
      if (quote && posixly_correct == 0 && ansic_shouldquote (var->value))
	{
	  t = ansic_quote (var->value, 0, (int *)0);
	  printf ("%s", t);
	  free (t);
	}
      else if (quote && sh_contains_shell_metas (var->value))
	{
	  t = sh_single_quote (var->value);
	  printf ("%s", t);
	  free (t);
	}
      else
	printf ("%s", var->value);
    }
}

/* Print the function cell of VAR, a shell variable.  Do not
   print the name, nor leading/trailing newline. */
void
print_var_function (var)
     SHELL_VAR *var;
{
  if (function_p (var) && var->value)
    printf ("%s", named_function_string ((char *)NULL, function_cell(var), 1));
}

/* **************************************************************** */
/*								    */
/*		 Dynamic Variable Extension			    */
/*								    */
/* **************************************************************** */

/* DYNAMIC VARIABLES

   These are variables whose values are generated anew each time they are
   referenced.  These are implemented using a pair of function pointers
   in the struct variable: assign_func, which is called from bind_variable,
   and dynamic_value, which is called from find_variable.

   assign_func is called from bind_variable, if bind_variable discovers
   that the variable being assigned to has such a function.  The function
   is called as
  	SHELL_VAR *temp = (*(entry->assign_func)) (entry, value)
   and the (SHELL_VAR *)temp is returned as the value of bind_variable.  It
   is usually ENTRY (self).

   dynamic_value is called from find_variable to return a `new' value for
   the specified dynamic varible.  If this function is NULL, the variable
   is treated as a `normal' shell variable.  If it is not, however, then
   this function is called like this:
  	tempvar = (*(var->dynamic_value)) (var);

   Sometimes `tempvar' will replace the value of `var'.  Other times, the
   shell will simply use the string value.  Pretty object-oriented, huh?

   Be warned, though: if you `unset' a special variable, it loses its
   special meaning, even if you subsequently set it.

   The special assignment code would probably have been better put in
   subst.c: do_assignment, in the same style as
   stupidly_hack_special_variables, but I wanted the changes as
   localized as possible.  */

#define INIT_DYNAMIC_VAR(var, val, gfunc, afunc) \
  do \
    { \
      v = bind_variable (var, (val)); \
      v->dynamic_value = gfunc; \
      v->assign_func = afunc; \
    } \
  while (0)

#define INIT_DYNAMIC_ARRAY_VAR(var, gfunc, afunc) \
  do \
    { \
      v = make_new_array_variable (var); \
      v->dynamic_value = gfunc; \
      v->assign_func = afunc; \
    } \
  while (0)

static SHELL_VAR *
null_assign (self, value)
     SHELL_VAR *self;
     char *value;
{
  return (self);
}

#if defined (ARRAY_VARS)
static SHELL_VAR *
null_array_assign (self, ind, value)
     SHELL_VAR *self;
     arrayind_t ind;
     char *value;
{
  return (self);
}
#endif

/* The value of $SECONDS.  This is the number of seconds since shell
   invocation, or, the number of seconds since the last assignment + the
   value of the last assignment. */
static long seconds_value_assigned;

static SHELL_VAR *
assign_seconds (self, value)
     SHELL_VAR *self;
     char *value;
{
  if (legal_number (value, &seconds_value_assigned) == 0)
    seconds_value_assigned = 0;
  shell_start_time = NOW;
  return (self);
}

static SHELL_VAR *
get_seconds (var)
     SHELL_VAR *var;
{
  time_t time_since_start;
  char *p;

  time_since_start = NOW - shell_start_time;
  p = itos(seconds_value_assigned + time_since_start);

  FREE (var->value);

  VSETATTR (var, att_integer);
  var->value = p;
  return (var);
}

static SHELL_VAR *
init_seconds_var ()
{
  SHELL_VAR *v;

  v = find_variable ("SECONDS");
  if (v)
    {
      if (legal_number (value_cell(v), &seconds_value_assigned) == 0)
	seconds_value_assigned = 0;
    }
  INIT_DYNAMIC_VAR ("SECONDS", (v ? v->value : (char *)NULL), get_seconds, assign_seconds);
  return v;      
}
     
/* The random number seed.  You can change this by setting RANDOM. */
static unsigned long rseed = 1;
static int last_random_value;

/* A linear congruential random number generator based on the example
   on in the ANSI C standard.  This one isn't very good, but a more
   complicated one is overkill. */

/* Returns a pseudo-random number between 0 and 32767. */
static int
brand ()
{
  rseed = rseed * 1103515245 + 12345;
  return ((unsigned int)((rseed >> 16) & 32767));	/* was % 32768 */
}

/* Set the random number generator seed to SEED. */
static void
sbrand (seed)
     unsigned long seed;
{
  rseed = seed;
  last_random_value = 0;
}

static SHELL_VAR *
assign_random (self, value)
     SHELL_VAR *self;
     char *value;
{
  sbrand (strtoul (value, (char **)NULL, 10));
  return (self);
}

int
get_random_number ()
{
  int rv;

  /* Reset for command and process substitution. */
  if (subshell_environment)
    sbrand (rseed + getpid() + NOW);

  do
    rv = brand ();
  while (rv == last_random_value);
  return rv;
}

static SHELL_VAR *
get_random (var)
     SHELL_VAR *var;
{
  int rv;
  char *p;

  rv = get_random_number ();
  last_random_value = rv;
  p = itos (rv);

  FREE (var->value);

  VSETATTR (var, att_integer);
  var->value = p;
  return (var);
}

/* Function which returns the current line number. */
static SHELL_VAR *
get_lineno (var)
     SHELL_VAR *var;
{
  char *p;
  int ln;

  ln = executing_line_number ();
  p = itos (ln);
  FREE (var->value);
  var->value = p;
  return (var);
}

static SHELL_VAR *
assign_lineno (var, value)
     SHELL_VAR *var;
     char *value;
{
  long new_value;

  if (value == 0 || *value == '\0' || legal_number (value, &new_value) == 0)
    new_value = 0;
  line_number = new_value;
  return var;
}

#if defined (HISTORY)
static SHELL_VAR *
get_histcmd (var)
     SHELL_VAR *var;
{
  char *p;

  p = itos (history_number ());
  FREE (var->value);
  var->value = p;
  return (var);
}
#endif

#if defined (PUSHD_AND_POPD) && defined (ARRAY_VARS)
static SHELL_VAR *
get_dirstack (self)
     SHELL_VAR *self;
{
  ARRAY *a;
  WORD_LIST *l;

  l = get_directory_stack ();
  a = word_list_to_array (l);
  dispose_array (array_cell (self));
  dispose_words (l);
  self->value = (char *)a;
  return self;
}

static  SHELL_VAR *
assign_dirstack (self, ind, value)
     SHELL_VAR *self;
     arrayind_t ind;
     char *value;
{
  set_dirstack_element (ind, 1, value);
  return self;
}

static SHELL_VAR *
init_dirstack_var ()
{
  SHELL_VAR *v;

  v = find_variable ("DIRSTACK");
  if (v)
    return v;
  INIT_DYNAMIC_ARRAY_VAR ("DIRSTACK", get_dirstack, assign_dirstack);
  return v;
}
#endif /* PUSHD AND POPD && ARRAY_VARS */

#if defined (ARRAY_VARS)
/* We don't want to initialize the group set with a call to getgroups()
   unless we're asked to, but we only want to do it once. */
static SHELL_VAR *
get_groupset (self)
     SHELL_VAR *self;
{
  register int i;
  int ng;
  ARRAY *a;
  static char **group_set = (char **)NULL;

  if (group_set == 0)
    {
      group_set = get_group_list (&ng);
      a = array_cell (self);
      for (i = 0; i < ng; i++)
	array_add_element (a, i, group_set[i]);
    }
  return (self);
}

static SHELL_VAR *
init_groups_var ()
{
  SHELL_VAR *v;

  v = find_variable ("GROUPS");
  if (v)
    return (v);
  INIT_DYNAMIC_ARRAY_VAR ("GROUPS", get_groupset, null_array_assign);
  VSETATTR (v, att_noassign);
  return v;
}
#endif /* ARRAY_VARS */

static SHELL_VAR *
get_funcname (self)
     SHELL_VAR *self;
{
  if (variable_context && this_shell_function)
    {
      FREE (self->value);
      self->value = savestring (this_shell_function->name);
    }
  return (self);
}

void
make_funcname_visible (on_or_off)
     int on_or_off;
{
  SHELL_VAR *v;

  v = find_variable ("FUNCNAME");
  if (v == 0 || v->dynamic_value == 0)
    return;

  if (on_or_off)
    VUNSETATTR (v, att_invisible);
  else
    VSETATTR (v, att_invisible);
}

static SHELL_VAR *
init_funcname_var ()
{
  SHELL_VAR *v;

  v = find_variable ("FUNCNAME");
  if (v)
    return v;
  INIT_DYNAMIC_VAR ("FUNCNAME", (char *)NULL, get_funcname, null_assign);
  VSETATTR (v, att_invisible|att_noassign);
  return v;
}

static void
initialize_dynamic_variables ()
{
  SHELL_VAR *v;

  v = init_seconds_var ();

  INIT_DYNAMIC_VAR ("RANDOM", (char *)NULL, get_random, assign_random);
  INIT_DYNAMIC_VAR ("LINENO", (char *)NULL, get_lineno, assign_lineno);

#if defined (HISTORY)
  INIT_DYNAMIC_VAR ("HISTCMD", (char *)NULL, get_histcmd, (DYNAMIC_FUNC *)NULL);
#endif

#if defined (PUSHD_AND_POPD) && defined (ARRAY_VARS)
  v = init_dirstack_var ();
#endif /* PUSHD_AND_POPD && ARRAY_VARS */

#if defined (ARRAY_VARS)
  v = init_groups_var ();
#endif

  v = init_funcname_var ();
}

/* How to get a pointer to the shell variable or function named NAME.
   HASHED_VARS is a pointer to the hash table containing the list
   of interest (either variables or functions). */
SHELL_VAR *
var_lookup (name, hashed_vars)
     const char *name;
     HASH_TABLE *hashed_vars;
{
  BUCKET_CONTENTS *bucket;

  bucket = find_hash_item (name, hashed_vars);
  return (bucket ? (SHELL_VAR *)bucket->data : (SHELL_VAR *)NULL);
}

/* Look up the variable entry named NAME.  If SEARCH_TEMPENV is non-zero,
   then also search the temporarily built list of exported variables. */
SHELL_VAR *
find_variable_internal (name, search_tempenv)
     const char *name;
     int search_tempenv;
{
  SHELL_VAR *var;

  var = (SHELL_VAR *)NULL;

  /* If explicitly requested, first look in the temporary environment for
     the variable.  This allows constructs such as "foo=x eval 'echo $foo'"
     to get the `exported' value of $foo.  This happens if we are executing
     a function or builtin, or if we are looking up a variable in a
     "subshell environment". */
  if ((search_tempenv || subshell_environment) &&
      (temporary_env || builtin_env || function_env))
    var = find_tempenv_variable (name);

  if (!var)
    var = var_lookup (name, shell_variables);

  if (!var)
    return ((SHELL_VAR *)NULL);

  return (var->dynamic_value ? (*(var->dynamic_value)) (var) : var);
}

/* Look up the variable entry named NAME.  Returns the entry or NULL. */
SHELL_VAR *
find_variable (name)
     const char *name;
{
  return (find_variable_internal
	  (name, (variable_context || this_shell_builtin || builtin_env)));
}

/* Look up the function entry whose name matches STRING.
   Returns the entry or NULL. */
SHELL_VAR *
find_function (name)
     const char *name;
{
  return (var_lookup (name, shell_functions));
}

/* Return the string value of a variable.  Return NULL if the variable
   doesn't exist, or only has a function as a value.  Don't cons a new
   string.  This is a potential memory leak if the variable is found
   in the temporary environment. */
char *
get_string_value (var_name)
     const char *var_name;
{
  SHELL_VAR *var;

  var = find_variable (var_name);

  if (!var)
    return (char *)NULL;
#if defined (ARRAY_VARS)
  else if (array_p (var))
    return (array_reference (array_cell (var), 0));
#endif
  else
    return (var->value);
}

/* This is present for use by the tilde and readline libraries. */
char *
sh_get_env_value (v)
     const char *v;
{
  return get_string_value (v);
}

/* Create a local variable referenced by NAME. */
SHELL_VAR *
make_local_variable (name)
     const char *name;
{
  SHELL_VAR *new_var, *old_var;
  BUCKET_CONTENTS *elt;

  /* local foo; local foo;  is a no-op. */
  old_var = find_variable (name);
  if (old_var && old_var->context == variable_context)
    return (old_var);

  /* Since this is called only from the local/declare/typeset code, we can
     call builtin_error here without worry (of course, it will also work
     for anything that sets this_command_name).  Variables with the `noassign'
     attribute may not be made local.  The test against old_var's context
     level is to disallow local copies of readonly global variables (since I
     believe that this could be a security hole).  Readonly copies of calling
     function local variables are OK. */
  if (old_var && (noassign_p (old_var) ||
		 (readonly_p (old_var) && old_var->context == 0)))
    {
      if (readonly_p (old_var))
	builtin_error ("%s: readonly variable", name);
      return ((SHELL_VAR *)NULL);
    }

  elt = remove_hash_item (name, shell_variables);
  if (elt)
    {
      old_var = (SHELL_VAR *)elt->data;
      free (elt->key);
      free (elt);
    }
  else
    old_var = (SHELL_VAR *)NULL;

  /* If a variable does not already exist with this name, then
     just make a new one. */
  if (old_var == 0)
    new_var = bind_variable (name, "");
  else
    {
      new_var = (SHELL_VAR *)xmalloc (sizeof (SHELL_VAR));

      new_var->name = savestring (name);
      new_var->value = (char *)xmalloc (1);
      new_var->value[0] = '\0';

      CLEAR_EXPORTSTR (new_var);

      new_var->dynamic_value = (DYNAMIC_FUNC *)NULL;
      new_var->assign_func = (DYNAMIC_FUNC *)NULL;

      new_var->attributes = exported_p (old_var) ? att_exported : 0;

      new_var->prev_context = old_var;
      elt = add_hash_item (savestring (name), shell_variables);
      elt->data = (char *)new_var;
    }

  new_var->context = variable_context;
  VSETATTR (new_var, att_local);

  /* XXX */
  if (variable_context >= local_variable_stack_size)
    {
      int old_size = local_variable_stack_size;
      RESIZE_MALLOCED_BUFFER (have_local_variables, variable_context, 1,
			      local_variable_stack_size, 8);
      bzero ((char *)have_local_variables + old_size,
	     local_variable_stack_size - old_size);
    }
  have_local_variables[variable_context] = 1;		/* XXX */

  return (new_var);
}

#if defined (ARRAY_VARS)
SHELL_VAR *
make_local_array_variable (name)
     char *name;
{
  SHELL_VAR *var;
  ARRAY *array;

  var = make_local_variable (name);
  if (var == 0)
    return var;
  array = new_array ();

  FREE (value_cell(var));
  var->value = (char *)array;
  VSETATTR (var, att_array);
  return var;
}
#endif /* ARRAY_VARS */

/* Create a new shell variable with name NAME and add it to the hash table
   of shell variables. */
static SHELL_VAR *
make_new_variable (name)
     const char *name;
{
  SHELL_VAR *entry;
  BUCKET_CONTENTS *elt;

  entry = (SHELL_VAR *)xmalloc (sizeof (SHELL_VAR));

  entry->attributes = 0;
  entry->name = savestring (name);
  entry->value = (char *)NULL;
  CLEAR_EXPORTSTR (entry);

  entry->dynamic_value = (DYNAMIC_FUNC *)NULL;
  entry->assign_func = (DYNAMIC_FUNC *)NULL;

  /* Always assume variables are to be made at toplevel!
     make_local_variable has the responsibilty of changing the
     variable context. */
  entry->context = 0;
  entry->prev_context = (SHELL_VAR *)NULL;

  /* Make sure we have a shell_variables hash table to add to. */
  if (shell_variables == 0)
    shell_variables = make_hash_table (0);

  elt = add_hash_item (savestring (name), shell_variables);
  elt->data = (char *)entry;

  return entry;
}

#if defined (ARRAY_VARS)
SHELL_VAR *
make_new_array_variable (name)
     char *name;
{
  SHELL_VAR *entry;
  ARRAY *array;

  entry = make_new_variable (name);
  array = new_array ();
  entry->value = (char *)array;
  VSETATTR (entry, att_array);
  return entry;
}
#endif

char *
make_variable_value (var, value)
     SHELL_VAR *var;
     char *value;
{
  char *retval;
  long lval;
  int expok;

  /* If this variable has had its type set to integer (via `declare -i'),
     then do expression evaluation on it and store the result.  The
     functions in expr.c (evalexp and bind_int_variable) are responsible
     for turning off the integer flag if they don't want further
     evaluation done. */
  if (integer_p (var))
    {
      lval = evalexp (value, &expok);
      if (expok == 0)
	jump_to_top_level (DISCARD);
      retval = itos (lval);
    }
  else if (value)
    {
      if (*value)
	retval = savestring (value);
      else
	{
	  retval = (char *)xmalloc (1);
	  retval[0] = '\0';
	}
    }
  else
    retval = (char *)NULL;

  return retval;
}

/* Bind a variable NAME to VALUE.  This conses up the name
   and value strings. */
SHELL_VAR *
bind_variable (name, value)
     const char *name;
     char *value;
{
  char *newval;
  SHELL_VAR *entry, *tempenv_entry;

  entry = (SHELL_VAR *)0;

  /* If we have a temporary environment, look there first for the variable,
     and, if found, modify the value there before modifying it in the
     shell_variables table.  This allows sourced scripts to modify values
     given to them in a temporary environment while modifying the variable
     value that the caller sees. */
  if (temporary_env || builtin_env || function_env)
    {
      tempenv_entry = find_tempenv_variable (name);
      if (tempenv_entry)
	{
	  dispose_variable (tempenv_entry);
	  tempenv_entry = bind_tempenv_variable (name, value);
	  dispose_variable (tempenv_entry);
	}
    }
    
  entry = var_lookup (name, shell_variables);

  if (entry == 0)
    {
      entry = make_new_variable (name);
      entry->value = make_variable_value (entry, value);
    }
  else if (entry->assign_func)	/* array vars have assign functions now */
    {
      INVALIDATE_EXPORTSTR (entry);
      return ((*(entry->assign_func)) (entry, value));
    }
  else
    {
      if (readonly_p (entry) || noassign_p (entry))
	{
	  if (readonly_p (entry))
	    report_error ("%s: readonly variable", name);
	  return (entry);
	}

      /* Variables which are bound are visible. */
      VUNSETATTR (entry, att_invisible);

      newval = make_variable_value (entry, value);

      /* Invalidate any cached export string */
      INVALIDATE_EXPORTSTR (entry);

#if defined (ARRAY_VARS)
      /* XXX -- this bears looking at again -- XXX */
      /* If an existing array variable x is being assigned to with x=b or
	 `read x' or something of that nature, silently convert it to
	 x[0]=b or `read x[0]'. */
      if (array_p (entry))
	{
	  array_add_element (array_cell (entry), 0, newval);
	  free (newval);
	}
      else
#endif
	{
	  FREE (entry->value);
	  entry->value = newval;
	}
    }

  if (mark_modified_vars)
    VSETATTR (entry, att_exported);

  if (exported_p (entry))
    array_needs_making = 1;

  return (entry);
}

/* Make VAR, a simple shell variable, have value VALUE.  Once assigned a
   value, variables are no longer invisible.  This is a duplicate of part
   of the internals of bind_variable.  If the variable is exported, or
   all modified variables should be exported, mark the variable for export
   and note that the export environment needs to be recreated. */
SHELL_VAR *
bind_variable_value (var, value)
     SHELL_VAR *var;
     char *value;
{
  char *t;

  VUNSETATTR (var, att_invisible);

  t = make_variable_value (var, value);
  FREE (var->value);
  var->value = t;

  INVALIDATE_EXPORTSTR (var);

  if (mark_modified_vars)
    VSETATTR (var, att_exported);

  if (exported_p (var))
    array_needs_making = 1;

  return (var);
}

/* Bind/create a shell variable with the name LHS to the RHS.
   This creates or modifies a variable such that it is an integer.

   This used to be in expr.c, but it is here so that all of the
   variable binding stuff is localized.  Since we don't want any
   recursive evaluation from bind_variable() (possible without this code,
   since bind_variable() calls the evaluator for variables with the integer
   attribute set), we temporarily turn off the integer attribute for each
   variable we set here, then turn it back on after binding as necessary. */

SHELL_VAR *
bind_int_variable (lhs, rhs)
     char *lhs, *rhs;
{
  register SHELL_VAR *v;
  int isint;

  isint = 0;
  v = find_variable (lhs);
  if (v)
    {
      isint = integer_p (v);
      VUNSETATTR (v, att_integer);
    }

  v = bind_variable (lhs, rhs);
  if (isint)
    VSETATTR (v, att_integer);

  return (v);
}

SHELL_VAR *
bind_var_to_int (var, val)
     char *var;
     long val;
{
  char ibuf[INT_STRLEN_BOUND (long) + 1], *p;

  p = fmtulong (val, 10, ibuf, sizeof (ibuf), 0);
  return (bind_int_variable (var, p));
}

/* Dispose of the information attached to VAR. */
void
dispose_variable (var)
     SHELL_VAR *var;
{
  if (!var)
    return;

  if (function_p (var))
    dispose_command (function_cell (var));
#if defined (ARRAY_VARS)
  else if (array_p (var))
    dispose_array (array_cell (var));
#endif
  else
    FREE (value_cell (var));

  FREE_EXPORTSTR (var);

  free (var->name);

  if (exported_p (var))
    array_needs_making = 1;

  free (var);
}

/* Unset the variable referenced by NAME. */
int
unbind_variable (name)
     const char *name;
{
  SHELL_VAR *var;

  var = find_variable (name);
  if (!var)
    return (-1);

  /* This function should never be called with an array variable name. */
#if defined (ARRAY_VARS)
  if (array_p (var) == 0 && var->value)
#else
  if (var->value)
#endif
    {
      free (var->value);
      var->value = (char *)NULL;
    }

  makunbound (name, shell_variables);

  return (0);
}

/* Make the variable associated with NAME go away.  HASH_LIST is the
   hash table from which this variable should be deleted (either
   shell_variables or shell_functions).
   Returns non-zero if the variable couldn't be found. */
int
makunbound (name, hash_list)
     const char *name;
     HASH_TABLE *hash_list;
{
  BUCKET_CONTENTS *elt, *new_elt;
  SHELL_VAR *old_var, *new_var;
  char *t;

  elt = remove_hash_item (name, hash_list);

  if (elt == 0)
    return (-1);

  old_var = (SHELL_VAR *)elt->data;
  new_var = old_var->prev_context;

  if (old_var && exported_p (old_var))
    array_needs_making++;

#if defined (PROGRAMMABLE_COMPLETION)
  if (hash_list == shell_functions)
    set_itemlist_dirty (&it_functions);
#endif

  /* If we're unsetting a local variable and we're still executing inside
     the function, just mark the variable as invisible.
     kill_all_local_variables will clean it up later.  This must be done
     so that if the variable is subsequently assigned a new value inside
     the function, the `local' attribute is still present.  We also need
     to add it back into the correct hash table. */
  if (old_var && local_p (old_var) && variable_context == old_var->context)
    {
      VSETATTR (old_var, att_invisible);
      INVALIDATE_EXPORTSTR (old_var);
      new_elt = add_hash_item (savestring (old_var->name), hash_list);
      new_elt->data = (char *)old_var;
      stupidly_hack_special_variables (old_var->name);
      free (elt->key);
      free (elt);
      return (0);
    }

  if (new_var)
    {
      /* Has to be a variable, functions don't have previous contexts. */
      new_elt = add_hash_item (savestring (new_var->name), hash_list);
      new_elt->data = (char *)new_var;

      if (exported_p (new_var))
	set_auto_export (new_var);
    }

  /* Have to save a copy of name here, because it might refer to
     old_var->name.  If so, stupidly_hack_special_variables will
     reference freed memory. */
  t = savestring (name);

  free (elt->key);
  free (elt);

  dispose_variable (old_var);
  stupidly_hack_special_variables (t);
  free (t);
  return (0);
}

#ifdef INCLUDE_UNUSED
/* Remove the variable with NAME if it is a local variable in the
   current context. */
int
kill_local_variable (name)
     const char *name;
{
  SHELL_VAR *temp;

  temp = find_variable (name);
  if (temp && temp->context == variable_context)
    {
      makunbound (name, shell_variables);
      return (0);
    }
  return (-1);
}
#endif

/* Get rid of all of the variables in the current context. */
int
variable_in_context (var)
     SHELL_VAR *var;
{
  return (var && var->context == variable_context);
}

void
kill_all_local_variables ()
{
  register int i, pass;
  register SHELL_VAR *var, **list;
  HASH_TABLE *varlist;

  /* If HAVE_LOCAL_VARIABLES == 0, it means that we don't have any local
     variables at all.  If VARIABLE_CONTEXT >= LOCAL_VARIABLE_STACK_SIZE,
     it means that we have some local variables, but not in this variable
     context (level of function nesting).  Also, if
     HAVE_LOCAL_VARIABLES[VARIABLE_CONTEXT] == 0, we have no local variables
     at this context. */
  if (have_local_variables == 0 ||
      variable_context >= local_variable_stack_size ||
      have_local_variables[variable_context] == 0)
    return;

  for (pass = 0; pass < 2; pass++)
    {
      varlist = pass ? shell_functions : shell_variables;

      list = map_over (variable_in_context, varlist);

      if (list)
	{
	  for (i = 0; var = list[i]; i++)
	    {
	      VUNSETATTR (var, att_local);
	      makunbound (var->name, varlist);
	    }
	  free (list);
	}
    }

  have_local_variables[variable_context] = 0;		/* XXX */
}

static void
free_variable_hash_data (data)
     PTR_T data;
{
  SHELL_VAR *var, *prev;

  var = (SHELL_VAR *)data;
  while (var)
    {
      prev = var->prev_context;
      dispose_variable (var);
      var = prev;
    }
}

/* Delete the entire contents of the hash table. */
void
delete_all_variables (hashed_vars)
     HASH_TABLE *hashed_vars;
{
  flush_hash_table (hashed_vars, free_variable_hash_data);
}

static SHELL_VAR *
new_shell_variable (name)
     const char *name;
{
  SHELL_VAR *var;

  var = (SHELL_VAR *)xmalloc (sizeof (SHELL_VAR));

  bzero ((char *)var, sizeof (SHELL_VAR));
  var->name = savestring (name);
  return (var);
}

/* Do a function binding to a variable.  You pass the name and
   the command to bind to.  This conses the name and command. */
SHELL_VAR *
bind_function (name, value)
     const char *name;
     COMMAND *value;
{
  SHELL_VAR *entry;

  entry = find_function (name);
  if (!entry)
    {
      BUCKET_CONTENTS *elt;

      elt = add_hash_item (savestring (name), shell_functions);

      entry = new_shell_variable (name);
      entry->dynamic_value = entry->assign_func = (DYNAMIC_FUNC *)NULL;
      CLEAR_EXPORTSTR (entry);

      /* Functions are always made at the top level.  This allows a
	 function to define another function (like autoload). */
      entry->context = 0;

      elt->data = (char *)entry;
    }

  INVALIDATE_EXPORTSTR (entry);

  if (entry->value)
    dispose_command ((COMMAND *)entry->value);

  entry->value = value ? (char *)copy_command (value) : (char *)NULL;
  VSETATTR (entry, att_function);

  if (mark_modified_vars)
    VSETATTR (entry, att_exported);

  VUNSETATTR (entry, att_invisible);		/* Just to be sure */

  if (exported_p (entry))
    array_needs_making = 1;

#if defined (PROGRAMMABLE_COMPLETION)
  set_itemlist_dirty (&it_functions);
#endif

  return (entry);
}

#ifdef INCLUDE_UNUSED
/* Copy VAR to a new data structure and return that structure. */
SHELL_VAR *
copy_variable (var)
     SHELL_VAR *var;
{
  SHELL_VAR *copy = (SHELL_VAR *)NULL;

  if (var)
    {
      copy = (SHELL_VAR *)xmalloc (sizeof (SHELL_VAR));

      copy->attributes = var->attributes;
      copy->name = savestring (var->name);

      if (function_p (var))
	copy->value = (char *)copy_command (function_cell (var));
#if defined (ARRAY_VARS)
      else if (array_p (var))
	copy->value = (char *)dup_array (array_cell (var));
#endif
      else if (value_cell (var))
	copy->value = savestring (value_cell (var));
      else
	copy->value = (char *)NULL;

      copy->dynamic_value = var->dynamic_value;
      copy->assign_func = var->assign_func;

      copy->exportstr = COPY_EXPORTSTR (var);

      copy->context = var->context;

      /* Don't bother copying previous contexts along with this variable. */
      copy->prev_context = (SHELL_VAR *)NULL;
    }
  return (copy);
}
#endif

#define FIND_OR_MAKE_VARIABLE(name, entry) \
  do \
    { \
      entry = find_variable (name); \
      if (!entry) \
	{ \
	  entry = bind_variable (name, ""); \
	  if (!no_invisible_vars) entry->attributes |= att_invisible; \
	} \
    } \
  while (0)

/* Make the variable associated with NAME be readonly.
   If NAME does not exist yet, create it. */
void
set_var_read_only (name)
     char *name;
{
  SHELL_VAR *entry;

  FIND_OR_MAKE_VARIABLE (name, entry);
  VSETATTR (entry, att_readonly);
}

#ifdef INCLUDE_UNUSED
/* Make the function associated with NAME be readonly.
   If NAME does not exist, we just punt, like auto_export code below. */
void
set_func_read_only (name)
     const char *name;
{
  SHELL_VAR *entry;

  entry = find_function (name);
  if (entry)
    VSETATTR (entry, att_readonly);
}

/* Make the variable associated with NAME be auto-exported.
   If NAME does not exist yet, create it. */
void
set_var_auto_export (name)
     char *name;
{
  SHELL_VAR *entry;

  FIND_OR_MAKE_VARIABLE (name, entry);
  set_auto_export (entry);
}

/* Make the function associated with NAME be auto-exported. */
void
set_func_auto_export (name)
     const char *name;
{
  SHELL_VAR *entry;

  entry = find_function (name);
  if (entry)
    set_auto_export (entry);
}
#endif

/* Returns non-zero if STRING is an assignment statement.  The returned value
   is the index of the `=' sign. */
int
assignment (string)
     const char *string;
{
  register unsigned char c;
  register int newi, indx;

  c = string[indx = 0];

  if (legal_variable_starter (c) == 0)
    return (0);

  while (c = string[indx])
    {
      /* The following is safe.  Note that '=' at the start of a word
	 is not an assignment statement. */
      if (c == '=')
	return (indx);

#if defined (ARRAY_VARS)
      if (c == '[')
	{
	  newi = skipsubscript (string, indx);
	  if (string[newi++] != ']')
	    return (0);
	  return ((string[newi] == '=') ? newi : 0);
	}
#endif /* ARRAY_VARS */

      /* Variable names in assignment statements may contain only letters,
	 digits, and `_'. */
      if (legal_variable_char (c) == 0)
	return (0);

      indx++;
    }
  return (0);
}

static int
visible_var (var)
     SHELL_VAR *var;
{
  return (invisible_p (var) == 0);
}

static SHELL_VAR **
_visible_names (table)
     HASH_TABLE *table;
{
  SHELL_VAR **list;

  list = map_over (visible_var, table);

  if (list /* && posixly_correct */)
    sort_variables (list);

  return (list);
}

SHELL_VAR **
all_visible_functions ()
{
  return (_visible_names (shell_functions));
}

SHELL_VAR **
all_visible_variables ()
{
  return (_visible_names (shell_variables));
}

/* Return non-zero if the variable VAR is visible and exported.  Array
   variables cannot be exported. */
static int
visible_and_exported (var)
     SHELL_VAR *var;
{
  return (invisible_p (var) == 0 && exported_p (var));
}

SHELL_VAR **
all_exported_variables ()
{
  SHELL_VAR **list;

  list = map_over (visible_and_exported, shell_variables);
  if (list)
    sort_variables (list);
  return (list);
}

#if defined (ARRAY_VARS)
/* Return non-zero if the variable VAR is visible and an array. */
static int
visible_array_vars (var)
     SHELL_VAR *var;
{
  return (invisible_p (var) == 0 && array_p (var));
}

SHELL_VAR **
all_array_variables ()
{
  SHELL_VAR **list;

  list = map_over (visible_array_vars, shell_variables);
  if (list)
    sort_variables (list);
  return (list);
}
#endif /* ARRAY_VARS */

char **
all_variables_matching_prefix (prefix)
     const char *prefix;
{
  SHELL_VAR **varlist;
  char **rlist;
  int vind, rind, plen;

  plen = STRLEN (prefix);
  varlist = all_visible_variables ();
  for (vind = 0; varlist && varlist[vind]; vind++)
    ;
  if (varlist == 0 || vind == 0)
    return ((char **)NULL);
  rlist = alloc_array (vind + 1);
  for (vind = rind = 0; varlist[vind]; vind++)
    {
      if (plen == 0 || STREQN (prefix, varlist[vind]->name, plen))
	rlist[rind++] = savestring (varlist[vind]->name);
    }
  rlist[rind] = (char *)0;
  free (varlist);

  return rlist;
}

static inline char *
mk_env_string (name, value)
     const char *name, *value;
{
  int name_len, value_len;
  char	*p;

  name_len = strlen (name);
  value_len = STRLEN (value);
  p = (char *)xmalloc (2 + name_len + value_len);
  strcpy (p, name);
  p[name_len] = '=';
  if (value && *value)
    strcpy (p + name_len + 1, value);
  else
    p[name_len + 1] = '\0';
  return (p);
}

#ifdef DEBUG
/* Debugging */
static int
valid_exportstr (v)
     SHELL_VAR *v;
{
  char *s;

  s = v->exportstr;
  if (legal_variable_starter ((unsigned char)*s) == 0)
    {
      internal_error ("invalid character %d in exportstr for %s", *s, v->name);
      return (0);
    }
  for (s = v->exportstr + 1; s && *s; s++)
    {
      if (*s == '=')
	break;
      if (legal_variable_char ((unsigned char)*s) == 0)
	{
	  internal_error ("invalid character %d in exportstr for %s", *s, v->name);
	  return (0);
	}
    }
  if (*s != '=')
    {
      internal_error ("no `=' in exportstr for %s", v->name);
      return (0);
    }
  return (1);
}
#endif

/* Make an array of assignment statements from the hash table
   HASHED_VARS which contains SHELL_VARs.  Only visible, exported
   variables are eligible. */
char **
make_var_array (hashed_vars)
     HASH_TABLE *hashed_vars;
{
  register int i, list_index;
  register SHELL_VAR *var;
  char **list, *value;
  SHELL_VAR **vars;

  vars = map_over (visible_and_exported, hashed_vars);

  if (vars == 0)
    return (char **)NULL;

  list = alloc_array ((1 + array_len ((char **)vars)));

#define USE_EXPORTSTR (value == var->exportstr)

  for (i = 0, list_index = 0; var = vars[i]; i++)
    {
#if defined (__CYGWIN__)
      /* We don't use the exportstr stuff on Cygwin at all. */
      INVALIDATE_EXPORTSTR (var);
#endif
      if (var->exportstr)
	value = var->exportstr;
      else if (function_p (var))
	value = named_function_string ((char *)NULL, function_cell (var), 0);
#if defined (ARRAY_VARS)
      else if (array_p (var))
#  if 0
	value = array_to_assignment_string (array_cell (var));
#  else
	continue;	/* XXX array vars cannot yet be exported */
#  endif
#endif
      else
	value = value_cell (var);

      if (value)
	{
	  /* Gee, I'd like to get away with not using savestring() if we're
	     using the cached exportstr... */
	  list[list_index] = USE_EXPORTSTR ? savestring (value)
					   : mk_env_string (var->name, value);

	  if (USE_EXPORTSTR == 0 && function_p (var))
	    {
	      SAVE_EXPORTSTR (var, list[list_index]);
	    }
	  list_index++;
#undef USE_EXPORTSTR

#if 0	/* not yet */
#if defined (ARRAY_VARS)
	  if (array_p (var))
	    free (value);
#endif
#endif
	}
    }

  free (vars);
  list[list_index] = (char *)NULL;
  return (list);
}

/* Add STRING to the array of foo=bar strings that we already
   have to add to the environment.  */
int
assign_in_env (string)
     const char *string;
{
  int size, offset;
  char *name, *temp, *value;
  SHELL_VAR *var;

  offset = assignment (string);
  name = savestring (string);
  value = (char *)NULL;

  if (name[offset] == '=')
    {
      name[offset] = 0;

      var = find_variable (name);
      if (var && (readonly_p (var) || noassign_p (var)))
	{
	  if (readonly_p (var))
	    report_error ("%s: readonly variable", name);
	  free (name);
  	  return (0);
	}

      temp = name + offset + 1;
      temp = (strchr (temp, '~') != 0) ? bash_tilde_expand (temp) : savestring (temp);

      value = expand_string_unsplit_to_string (temp, 0);
      free (temp);
    }

  temp = mk_env_string (name, value);
  FREE (value);
  free (name);

  if (temporary_env == 0)
    {
      temporary_env = (char **)xmalloc (sizeof (char *));
      temporary_env [0] = (char *)NULL;
    }

  size = array_len (temporary_env);
  temporary_env = (char **)
    xrealloc (temporary_env, (size + 2) * (sizeof (char *)));

  temporary_env[size] = temp;
  temporary_env[size + 1] = (char *)NULL;
  array_needs_making = 1;

  if (echo_command_at_execute)
    {
      /* The Korn shell prints the `+ ' in front of assignment statements,
	 so we do too. */
      fprintf (stderr, "%s%s\n", indirection_level_string (), temp);
      fflush (stderr);
    }

  return 1;
}

/* Create a SHELL_VAR from a `name=value' string as in the environment, taking
   the variable name, the environment string, and an index into the string
   which is the offset of the `=' (the char before the value begins). */
static SHELL_VAR *
shell_var_from_env_string (name, env_string, l)
     const char *name;
     char *env_string;
     int l;
{
  SHELL_VAR *temp;
  char *w;

  /* This is a potential memory leak.  The code should really save
     the created variables in some auxiliary data structure, which
     can be disposed of at the appropriate time. */
  temp = new_shell_variable (name);
  w = env_string + l + 1;

  temp->value = *w ? savestring (w) : (char *)NULL;

  temp->attributes = att_exported|att_tempvar;
  temp->context = 0;
  temp->prev_context = (SHELL_VAR *)NULL;

  temp->dynamic_value = temp->assign_func = (DYNAMIC_FUNC *)NULL;
  CLEAR_EXPORTSTR (temp);

  return (temp);
}

/* Bind NAME to VALUE in ARRAY, an array of strings in the same format as the
   environment array (i.e, name=value).  If NAME is present, change the value,
   cons up a new SHELL_VAR and return it.  Otherwise return (SHELL_VAR *)NULL. */

static SHELL_VAR *
bind_name_in_env_array (name, value, array)
     const char *name;
     char *value;
     char **array;
{
  register int i, l;
  char *new_env_string;
  SHELL_VAR *temp;

  if (array == 0)
    return ((SHELL_VAR *)NULL);

  for (i = 0, l = strlen (name); array[i]; i++)
    {
      if (STREQN (array[i], name, l) && array[i][l] == '=')
	{
	  new_env_string = mk_env_string (name, value);

	  temp = shell_var_from_env_string (name, new_env_string, l);

	  free (array[i]);
	  array[i] = new_env_string;

	  return (temp);
	}
    }
  return ((SHELL_VAR *)NULL);
}

/* Search for NAME in ARRAY, an array of strings in the same format as the
   environment array (i.e, name=value).  If NAME is present, make a new
   variable and return it.  Otherwise, return NULL. */
static SHELL_VAR *
find_name_in_env_array (name, array)
     const char *name;
     char **array;
{
  register int i, l;
  SHELL_VAR *temp;

  if (array == 0)
    return ((SHELL_VAR *)NULL);

  for (i = 0, l = strlen (name); array[i]; i++)
    {
      if (STREQN (array[i], name, l) && array[i][l] == '=')
	{
	  temp = shell_var_from_env_string (name, array[i], l);
	  return (temp);
	}
    }
  return ((SHELL_VAR *)NULL);
}

#define FIND_AND_BIND_IN_ENV_ARRAY(N, V, A) \
  do \
    { \
      var = find_name_in_env_array (N, A); \
      if (var) \
	{ \
	  dispose_variable (var); \
	  var = bind_name_in_env_array (N, V, A); \
	  return (var); \
	} \
    } \
  while (0)

/* Make variable NAME have VALUE in one of the temporary environments. */
static SHELL_VAR *
bind_tempenv_variable (name, value)
     const char *name;
     char *value;
{
  SHELL_VAR *var;

  var = (SHELL_VAR *)NULL;

  if (temporary_env)
    FIND_AND_BIND_IN_ENV_ARRAY (name, value, temporary_env);

  /* We don't check this_shell_builtin because the command that needs the
     value from builtin_env may be a disk command run inside a script run
     with `.' and a temporary env. */
  if (builtin_env)
    FIND_AND_BIND_IN_ENV_ARRAY (name, value, builtin_env);

  if (variable_context && function_env)
    FIND_AND_BIND_IN_ENV_ARRAY (name, value, function_env);

  return (SHELL_VAR *)NULL;
}

/* Find a variable in the temporary environment that is named NAME.
   The temporary environment can be either the environment provided
   to a simple command, or the environment provided to a shell function.
   We only search the function environment if we are currently executing
   a shell function body (variable_context > 0).  Return a consed variable,
   or NULL if not found. */
SHELL_VAR *
find_tempenv_variable (name)
     const char *name;
{
  SHELL_VAR *var;

  var = (SHELL_VAR *)NULL;

  if (temporary_env)
    var = find_name_in_env_array (name, temporary_env);

  /* We don't check this_shell_builtin because the command that needs the
     value from builtin_env may be a disk command run inside a script run
     with `.' and a temporary env. */
  if (!var && builtin_env)
    var = find_name_in_env_array (name, builtin_env);

  if (!var && variable_context && function_env)
    var = find_name_in_env_array (name, function_env);

  return (var);
}

/* Free the storage allocated to the string array pointed to by ARRAYP, and
   make that variable have a null pointer as a value. */
static void
dispose_temporary_vars (arrayp)
     char ***arrayp;
{
  if (!*arrayp)
    return;

  free_array (*arrayp);
  *arrayp = (char **)NULL;
  array_needs_making = 1;
}

/* Free the storage used in the variable array for temporary
   environment variables. */
void
dispose_used_env_vars ()
{
  dispose_temporary_vars (&temporary_env);
}

/* Free the storage used for temporary environment variables given to
   commands when executing inside of a function body. */
void
dispose_function_env ()
{
  dispose_temporary_vars (&function_env);
}

/* Free the storage used for temporary environment variables given to
   commands when executing a builtin command such as "source". */
void
dispose_builtin_env ()
{
  dispose_temporary_vars (&builtin_env);
}

/* Take all of the shell variables in ENV_ARRAY and make shell variables
   from them at the current variable context. */
static void
merge_env_array (env_array)
     char **env_array;
{
  register int i, l;
  SHELL_VAR *temp;
  char *val, *name;

  if (env_array == 0)
    return;

  for (i = 0; env_array[i]; i++)
    {
      l = assignment (env_array[i]);
      name = env_array[i];
      val = env_array[i] + l + 1;
      name[l] = '\0';
      temp = bind_variable (name, val);
      name[l] = '=';
    }
}

void
merge_temporary_env ()
{
  merge_env_array (temporary_env);
}

void
merge_builtin_env ()
{
  merge_env_array (builtin_env);
}

void
merge_function_env ()
{
  merge_env_array (function_env);
}

#ifdef INCLUDE_UNUSED
int
any_temporary_variables ()
{
  return (temporary_env || function_env);
}
#endif

/* Add ENVSTR to the end of the exported environment, EXPORT_ENV. */
#define add_to_export_env(envstr,do_alloc) \
do \
  { \
    if (export_env_index >= (export_env_size - 1)) \
      { \
	export_env_size += 16; \
	export_env = (char **)xrealloc (export_env, export_env_size * sizeof (char *)); \
      } \
    export_env[export_env_index++] = (do_alloc) ? savestring (envstr) : envstr; \
    export_env[export_env_index] = (char *)NULL; \
  } while (0)

#define ISFUNCTION(s, o) ((s[o + 1] == '(')  && (s[o + 2] == ')'))

/* Add ASSIGN to EXPORT_ENV, or supercede a previous assignment in the
   array with the same left-hand side.  Return the new EXPORT_ENV. */
char **
add_or_supercede_exported_var (assign, do_alloc)
     char *assign;
     int do_alloc;
{
  register int i;
  int equal_offset;

  equal_offset = assignment (assign);
  if (equal_offset == 0)
    return (export_env);

  /* If this is a function, then only supercede the function definition.
     We do this by including the `=(' in the comparison.  */
  if (assign[equal_offset + 1] == '(')
    equal_offset++;

  for (i = 0; i < export_env_index; i++)
    {
      if (STREQN (assign, export_env[i], equal_offset + 1))
	{
	  free (export_env[i]);
	  export_env[i] = do_alloc ? savestring (assign) : assign;
	  return (export_env);
	}
    }
  add_to_export_env (assign, do_alloc);
  return (export_env);
}

/* Make the environment array for the command about to be executed, if the
   array needs making.  Otherwise, do nothing.  If a shell action could
   change the array that commands receive for their environment, then the
   code should `array_needs_making++'. */
void
maybe_make_export_env ()
{
  register int i;
  register char **temp_array;
  int new_size;

  if (array_needs_making)
    {
      if (export_env)
	free_array_members (export_env);

      /* Make a guess based on how many shell variables and functions we
	 have.  Since there will always be array variables, and array
	 variables are not (yet) exported, this will always be big enough
	 for the exported variables and functions, without any temporary
	 or function environments. */
      new_size = HASH_ENTRIES (shell_variables) + HASH_ENTRIES (shell_functions) + 1;
      if (new_size > export_env_size)
	{
	  export_env_size = new_size;
	  export_env = (char **)xrealloc (export_env, export_env_size * sizeof (char *));
	}
      export_env[export_env_index = 0] = (char *)NULL;

      temp_array = make_var_array (shell_variables);
      if (temp_array)
	{
	  for (i = 0; temp_array[i]; i++)
	    add_to_export_env (temp_array[i], 0);
	  free (temp_array);
	}

#if defined (RESTRICTED_SHELL)
      /* Restricted shells may not export shell functions. */
      temp_array = restricted ? (char **)0 : make_var_array (shell_functions);
#else
      temp_array = make_var_array (shell_functions);
#endif
      if (temp_array)
	{
	  for (i = 0; temp_array[i]; i++)
	    add_to_export_env (temp_array[i], 0);
	  free (temp_array);
	}

      if (function_env)
	for (i = 0; function_env[i]; i++)
	  export_env = add_or_supercede_exported_var (function_env[i], 1);

      if (builtin_env)
	for (i = 0; builtin_env[i]; i++)
	  export_env = add_or_supercede_exported_var (builtin_env[i], 1);

      if (temporary_env)
	for (i = 0; temporary_env[i]; i++)
	  export_env = add_or_supercede_exported_var (temporary_env[i], 1);

#if 0
      /* If we changed the array, then sort it alphabetically. */
      if (posixly_correct == 0 && (temporary_env || function_env))
	sort_char_array (export_env);
#endif

      array_needs_making = 0;
    }
}

/* This is an efficiency hack.  PWD and OLDPWD are auto-exported, so
   we will need to remake the exported environment every time we
   change directories.  `_' is always put into the environment for
   every external command, so without special treatment it will always
   cause the environment to be remade.

   If there is no other reason to make the exported environment, we can
   just update the variables in place and mark the exported environment
   as no longer needing a remake. */
void
update_export_env_inplace (env_prefix, preflen, value)
     char *env_prefix;
     int preflen;
     char *value;
{
  char *evar;

  evar = (char *)xmalloc (STRLEN (value) + preflen + 1);
  strcpy (evar, env_prefix);
  if (value)
    strcpy (evar + preflen, value);
  export_env = add_or_supercede_exported_var (evar, 0);
}

/* We always put _ in the environment as the name of this command. */
void
put_command_name_into_env (command_name)
     char *command_name;
{
  update_export_env_inplace ("_=", 2, command_name);
}

#if 0	/* UNUSED -- it caused too many problems */
void
put_gnu_argv_flags_into_env (pid, flags_string)
     long pid;
     char *flags_string;
{
  char *dummy, *pbuf;
  int l, fl;

  pbuf = itos (pid);
  l = strlen (pbuf);

  fl = strlen (flags_string);

  dummy = (char *)xmalloc (l + fl + 30);
  dummy[0] = '_';
  strcpy (dummy + 1, pbuf);
  strcpy (dummy + 1 + l, "_GNU_nonoption_argv_flags_");
  dummy[l + 27] = '=';
  strcpy (dummy + l + 28, flags_string);

  free (pbuf);

  export_env = add_or_supercede_exported_var (dummy, 0);
}
#endif

/* Return a string denoting what our indirection level is. */
static char indirection_string[100];

char *
indirection_level_string ()
{
  register int i, j;
  char *ps4;

  indirection_string[0] = '\0';
  ps4 = get_string_value ("PS4");

  if (ps4 == 0 || *ps4 == '\0')
    return (indirection_string);

  ps4 = decode_prompt_string (ps4);

  for (i = 0; *ps4 && i < indirection_level && i < 99; i++)
    indirection_string[i] = *ps4;

  for (j = 1; *ps4 && ps4[j] && i < 99; i++, j++)
    indirection_string[i] = ps4[j];

  indirection_string[i] = '\0';
  free (ps4);
  return (indirection_string);
}

/*************************************************
 *						 *
 *	Functions to manage special variables	 *
 *						 *
 *************************************************/

/* Extern declarations for variables this code has to manage. */
extern int eof_encountered, eof_encountered_limit, ignoreeof;

#if defined (READLINE)
extern int no_line_editing;
extern int hostname_list_initialized;
#endif

/* An alist of name.function for each special variable.  Most of the
   functions don't do much, and in fact, this would be faster with a
   switch statement, but by the end of this file, I am sick of switch
   statements. */

#define SET_INT_VAR(name, intvar)  intvar = find_variable (name) != 0

struct name_and_function {
  char *name;
  sh_sv_func_t *function;
} special_vars[] = {
  { "PATH", sv_path },
  { "MAIL", sv_mail },
  { "MAILPATH", sv_mail },
  { "MAILCHECK", sv_mail },

  { "POSIXLY_CORRECT", sv_strict_posix },
  { "GLOBIGNORE", sv_globignore },

  /* Variables which only do something special when READLINE is defined. */
#if defined (READLINE)
  { "TERM", sv_terminal },
  { "TERMCAP", sv_terminal },
  { "TERMINFO", sv_terminal },
  { "HOSTFILE", sv_hostfile },
#endif /* READLINE */

  /* Variables which only do something special when HISTORY is defined. */
#if defined (HISTORY)
  { "HISTIGNORE", sv_histignore },
  { "HISTSIZE", sv_histsize },
  { "HISTFILESIZE", sv_histsize },
  { "HISTCONTROL", sv_history_control },
#  if defined (BANG_HISTORY)
  { "histchars", sv_histchars },
#  endif /* BANG_HISTORY */
#endif /* HISTORY */

  { "IGNOREEOF", sv_ignoreeof },
  { "ignoreeof", sv_ignoreeof },

  { "OPTIND", sv_optind },
  { "OPTERR", sv_opterr },

  { "TEXTDOMAIN", sv_locale },
  { "TEXTDOMAINDIR", sv_locale },
  { "LC_ALL", sv_locale },
  { "LC_COLLATE", sv_locale },
  { "LC_CTYPE", sv_locale },
  { "LC_MESSAGES", sv_locale },
  { "LC_NUMERIC", sv_locale },
  { "LANG", sv_locale },

#if defined (HAVE_TZSET) && defined (PROMPT_STRING_DECODE)
  { "TZ", sv_tz },
#endif

  { (char *)0, (sh_sv_func_t *)0 }
};

/* The variable in NAME has just had its state changed.  Check to see if it
   is one of the special ones where something special happens. */
void
stupidly_hack_special_variables (name)
     char *name;
{
  int i;

  for (i = 0; special_vars[i].name; i++)
    {
      if (STREQ (special_vars[i].name, name))
	{
	  (*(special_vars[i].function)) (name);
	  return;
	}
    }
}

/* What to do just after the PATH variable has changed. */
void
sv_path (name)
     char *name;
{
  /* hash -r */
  flush_hashed_filenames ();
}

/* What to do just after one of the MAILxxxx variables has changed.  NAME
   is the name of the variable.  This is called with NAME set to one of
   MAIL, MAILCHECK, or MAILPATH.  */
void
sv_mail (name)
     char *name;
{
  /* If the time interval for checking the files has changed, then
     reset the mail timer.  Otherwise, one of the pathname vars
     to the users mailbox has changed, so rebuild the array of
     filenames. */
  if (name[4] == 'C')  /* if (strcmp (name, "MAILCHECK") == 0) */
    reset_mail_timer ();
  else
    {
      free_mail_files ();
      remember_mail_dates ();
    }
}

/* What to do when GLOBIGNORE changes. */
void
sv_globignore (name)
     char *name;
{
  setup_glob_ignore (name);
}

#if defined (READLINE)
/* What to do just after one of the TERMxxx variables has changed.
   If we are an interactive shell, then try to reset the terminal
   information in readline. */
void
sv_terminal (name)
     char *name;
{
  if (interactive_shell && no_line_editing == 0)
    rl_reset_terminal (get_string_value ("TERM"));
}

void
sv_hostfile (name)
     char *name;
{
  SHELL_VAR *v;

  v = find_variable (name);
  if (v == 0)
    clear_hostname_list ();
  else
    hostname_list_initialized = 0;
}
#endif /* READLINE */

#if defined (HISTORY)
/* What to do after the HISTSIZE or HISTFILESIZE variables change.
   If there is a value for this HISTSIZE (and it is numeric), then stifle
   the history.  Otherwise, if there is NO value for this variable,
   unstifle the history.  If name is HISTFILESIZE, and its value is
   numeric, truncate the history file to hold no more than that many
   lines. */
void
sv_histsize (name)
     char *name;
{
  char *temp;
  long num;

  temp = get_string_value (name);

  if (temp && *temp)
    {
      if (legal_number (temp, &num))
	{
	  if (name[4] == 'S')
	    {
	      stifle_history (num);
	      num = where_history ();
	      if (history_lines_this_session > num)
		history_lines_this_session = num;
	    }
	  else
	    {
	      history_truncate_file (get_string_value ("HISTFILE"), (int)num);
	      if (num <= history_lines_in_file)
		history_lines_in_file = num;
	    }
	}
    }
  else if (name[4] == 'S')
    unstifle_history ();
}

/* What to do after the HISTIGNORE variable changes. */
void
sv_histignore (name)
     char *name;
{
  setup_history_ignore (name);
}

/* What to do after the HISTCONTROL variable changes. */
void
sv_history_control (name)
     char *name;
{
  char *temp;

  history_control = 0;
  temp = get_string_value (name);

  if (temp && *temp && STREQN (temp, "ignore", 6))
    {
      if (temp[6] == 's')	/* ignorespace */
	history_control = 1;
      else if (temp[6] == 'd')	/* ignoredups */
	history_control = 2;
      else if (temp[6] == 'b')	/* ignoreboth */
	history_control = 3;
    }
}

#if defined (BANG_HISTORY)
/* Setting/unsetting of the history expansion character. */
void
sv_histchars (name)
     char *name;
{
  char *temp;

  temp = get_string_value (name);
  if (temp)
    {
      history_expansion_char = *temp;
      if (temp[0] && temp[1])
	{
	  history_subst_char = temp[1];
	  if (temp[2])
	      history_comment_char = temp[2];
	}
    }
  else
    {
      history_expansion_char = '!';
      history_subst_char = '^';
      history_comment_char = '#';
    }
}
#endif /* BANG_HISTORY */
#endif /* HISTORY */

#if defined (HAVE_TZSET) && defined (PROMPT_STRING_DECODE)
void
sv_tz (name)
     char *name;
{
  tzset ();
}
#endif

/* If the variable exists, then the value of it can be the number
   of times we actually ignore the EOF.  The default is small,
   (smaller than csh, anyway). */
void
sv_ignoreeof (name)
     char *name;
{
  SHELL_VAR *tmp_var;
  char *temp;

  eof_encountered = 0;

  tmp_var = find_variable (name);
  ignoreeof = tmp_var != 0;
  temp = tmp_var ? value_cell (tmp_var) : (char *)NULL;
  if (temp)
    eof_encountered_limit = (*temp && all_digits (temp)) ? atoi (temp) : 10;
  set_shellopts ();	/* make sure `ignoreeof' is/is not in $SHELLOPTS */
}

void
sv_optind (name)
     char *name;
{
  char *tt;
  int s;

  tt = get_string_value ("OPTIND");
  if (tt && *tt)
    {
      s = atoi (tt);

      /* According to POSIX, setting OPTIND=1 resets the internal state
	 of getopt (). */
      if (s < 0 || s == 1)
	s = 0;
    }
  else
    s = 0;
  getopts_reset (s);
}

void
sv_opterr (name)
     char *name;
{
  char *tt;

  tt = get_string_value ("OPTERR");
  sh_opterr = (tt && *tt) ? atoi (tt) : 1;
}

void
sv_strict_posix (name)
     char *name;
{
  SET_INT_VAR (name, posixly_correct);
  posix_initialize (posixly_correct);
#if defined (READLINE)
  if (interactive_shell)
    posix_readline_initialize (posixly_correct);
#endif /* READLINE */
  set_shellopts ();	/* make sure `posix' is/is not in $SHELLOPTS */
}

void
sv_locale (name)
     char *name;
{
  char *v;

  v = get_string_value (name);
  if (name[0] == 'L' && name[1] == 'A')	/* LANG */
    set_lang (name, v);
  else
    set_locale_var (name, v);		/* LC_*, TEXTDOMAIN* */
}

#if defined (ARRAY_VARS)
void
set_pipestatus_array (ps)
     int *ps;
{
  SHELL_VAR *v;
  ARRAY *a;
  register int i;
  char *t, tbuf[INT_STRLEN_BOUND(int) + 1];

  v = find_variable ("PIPESTATUS");
  if (v == 0)
    v = make_new_array_variable ("PIPESTATUS");
  if (array_p (v) == 0)
    return;		/* Do nothing if not an array variable. */
  a = array_cell (v);
  if (a)
    empty_array (a);
  for (i = 0; ps[i] != -1; i++)
    {
      t = inttostr (ps[i], tbuf, sizeof (tbuf));
      array_add_element (a, i, t);
    }
}
#endif

void
set_pipestatus_from_exit (s)
     int s;
{
#if defined (ARRAY_VARS)
  static int v[2] = { 0, -1 };

  v[0] = s;
  set_pipestatus_array (v);
#endif
}