all messages for Guix-related lists mirrored at yhetil.org
 help / color / mirror / code / Atom feed
blob 99a3b45004a65a1239b588c0d319a7918f329673 88730 bytes (raw)
name: guix/build/syscalls.scm 	 # note: path name is non-authoritative(*)

   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
 
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2015 David Thompson <davet@gnu.org>
;;; Copyright © 2015 Mark H Weaver <mhw@netris.org>
;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
;;; Copyright © 2019 Guillaume Le Vaillant <glv@posteo.net>
;;; Copyright © 2020 Julien Lepiller <julien@lepiller.eu>
;;; Copyright © 2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
;;; Copyright © 2021 Chris Marusich <cmmarusich@gmail.com>
;;; Copyright © 2021 Tobias Geerinckx-Rice <me@tobias.gr>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix 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 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix 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 GNU Guix.  If not, see <http://www.gnu.org/licenses/>.

(define-module (guix build syscalls)
  #:use-module (system foreign)
  #:use-module (system base target)
  #:use-module (rnrs bytevectors)
  #:autoload   (ice-9 binary-ports) (get-bytevector-n)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-9)
  #:use-module (srfi srfi-9 gnu)
  #:use-module (srfi srfi-11)
  #:use-module (srfi srfi-19)
  #:use-module (srfi srfi-26)
  #:use-module (ice-9 rdelim)
  #:use-module (ice-9 regex)
  #:use-module (ice-9 match)
  #:use-module (ice-9 ftw)
  #:export (MS_RDONLY
            MS_NOSUID
            MS_NODEV
            MS_NOEXEC
            MS_REMOUNT
            MS_NOATIME
            MS_STRICTATIME
            MS_RELATIME
            MS_BIND
            MS_MOVE
            MS_LAZYTIME
            MNT_FORCE
            MNT_DETACH
            MNT_EXPIRE
            UMOUNT_NOFOLLOW

            restart-on-EINTR

            device-number
            device-number->major+minor

            mount?
            mount-device-number
            mount-source
            mount-point
            mount-type
            mount-options
            mount-flags

            mounts
            mount-points

            swapon
            swapoff

            file-system?
            file-system-type
            file-system-block-size
            file-system-block-count
            file-system-blocks-free
            file-system-blocks-available
            file-system-file-count
            file-system-free-file-nodes
            file-system-identifier
            file-system-maximum-name-length
            file-system-fragment-size
            file-system-mount-flags
            statfs

            ST_RDONLY
            ST_NOSUID
            ST_NODEV
            ST_NOEXEC
            ST_SYNCHRONOUS
            ST_MANDLOCK
            ST_WRITE
            ST_APPEND
            ST_IMMUTABLE
            ST_NOATIME
            ST_NODIRATIME
            ST_RELATIME
            statfs-flags->mount-flags

            free-disk-space
            device-in-use?
            add-to-entropy-count

            processes
            mkdtemp!
            fdatasync
            pivot-root
            scandir*
            getxattr
            setxattr

            fcntl-flock
            lock-file
            unlock-file
            with-file-lock
            with-file-lock/no-wait

            set-thread-name
            thread-name

            CLONE_CHILD_CLEARTID
            CLONE_CHILD_SETTID
            CLONE_NEWNS
            CLONE_NEWUTS
            CLONE_NEWIPC
            CLONE_NEWUSER
            CLONE_NEWPID
            CLONE_NEWNET
            clone
            setns

            PF_PACKET
            AF_PACKET
            all-network-interface-names
            network-interface-names
            network-interface-netmask
            network-interface-running?
            loopback-network-interface?
            arp-network-interface?
            network-interface-address
            set-network-interface-netmask
            set-network-interface-up
            configure-network-interface
            add-network-route/gateway
            delete-network-route

            interface?
            interface-name
            interface-flags
            interface-address
            interface-netmask
            interface-broadcast-address
            network-interfaces

            termios?
            termios-input-flags
            termios-output-flags
            termios-control-flags
            termios-local-flags
            termios-line-discipline
            termios-control-chars
            termios-input-speed
            termios-output-speed
            local-flags
            input-flags
            tcsetattr-action
            tcgetattr
            tcsetattr

            window-size?
            window-size-rows
            window-size-columns
            window-size-x-pixels
            window-size-y-pixels
            terminal-window-size
            terminal-columns
            terminal-rows

            utmpx?
            utmpx-login-type
            utmpx-pid
            utmpx-line
            utmpx-id
            utmpx-user
            utmpx-host
            utmpx-termination-status
            utmpx-exit-status
            utmpx-session-id
            utmpx-time
            utmpx-address
            login-type
            utmpx-entries
            (read-utmpx-from-port . read-utmpx)))

;;; Commentary:
;;;
;;; This module provides bindings to libc's syscall wrappers.  It uses the
;;; FFI, and thus requires a dynamically-linked Guile.
;;;
;;; Some syscalls are already defined in statically-linked Guile by applying
;;; 'guile-linux-syscalls.patch'.
;;;
;;; Visibility of syscall's symbols shared between this module and static Guile
;;; is a bit delicate. It is handled by 'define-as-needed' macro.
;;;
;;; This macro is used to export symbols in dynamic Guile context, and to
;;; re-export them in static Guile context.
;;;
;;; This way, even if they don't appear in #:export list, it is safe to use
;;; syscalls from this module in static or dynamic Guile context.
;;;
;;; Code:

\f
;;;
;;; Packed structures.
;;;

(define-syntax sizeof*
  ;; XXX: This duplicates 'compile-time-value'.
  (syntax-rules (int128 array)
    ((_ int128)
     16)
    ((_ (array type n))
     (* (sizeof* type) n))
    ((_ type)
     (let-syntax ((v (lambda (s)
                       ;; When compiling natively, call 'sizeof' at expansion
                       ;; time; otherwise, emit code to call it at run time.
                       (syntax-case s ()
                         (_
                          (if (= (target-word-size)
                                 (with-target %host-type target-word-size))
                              (sizeof type)
                              #'(sizeof type)))))))
       v))))

(define-syntax alignof*
  ;; XXX: This duplicates 'compile-time-value'.
  (syntax-rules (int128 array)
    ((_ int128)
     16)
    ((_ (array type n))
     (alignof* type))
    ((_ type)
     (let-syntax ((v (lambda (s)
                       ;; When compiling natively, call 'sizeof' at expansion
                       ;; time; otherwise, emit code to call it at run time.
                       (syntax-case s ()
                         (_
                          (if (= (target-word-size)
                                 (with-target %host-type target-word-size))
                              (alignof type)
                              #'(alignof type)))))))
       v))))

(define-syntax align                             ;as found in (system foreign)
  (syntax-rules (~)
    "Add to OFFSET whatever it takes to get proper alignment for TYPE."
    ((_ offset (type ~ endianness))
     (align offset type))
    ((_ offset type)
     (1+ (logior (1- offset) (1- (alignof* type)))))))

(define-syntax type-size
  (syntax-rules (~)
    ((_ (type ~ order))
     (sizeof* type))
    ((_ type)
     (sizeof* type))))

(define-syntax struct-alignment
  (syntax-rules ()
    "Compute the alignment for the aggregate made of TYPES at OFFSET.  The
result is the alignment of the \"most strictly aligned component\"."
    ((_ offset types ...)
     (max (align offset types) ...))))

(define-syntax struct-size
  (syntax-rules ()
    "Return the size in bytes of the structure made of TYPES."
    ((_ offset (types-processed ...))
     ;; The SysV ABI P.S. says: "Aggregates (structures and arrays) and unions
     ;; assume the alignment of their most strictly aligned component."  As an
     ;; example, a struct such as "int32, int16" has size 8, not 6.
     (1+ (logior (1- offset)
                 (1- (struct-alignment offset types-processed ...)))))
    ((_ offset (types-processed ...) type0 types ...)
     (struct-size (+ (type-size type0) (align offset type0))
                  (type0 types-processed ...)
                  types ...))))

(define-syntax write-type
  (syntax-rules (~ array *)
    ((_ bv offset (type ~ order) value)
     (bytevector-uint-set! bv offset value
                           (endianness order) (sizeof* type)))
    ((_ bv offset (array type n) value)
     (let loop ((i 0)
                (value value)
                (o offset))
       (unless (= i n)
         (match value
           ((head . tail)
            (write-type bv o type head)
            (loop (+ 1 i) tail (+ o (sizeof* type))))))))
    ((_ bv offset '* value)
     (bytevector-uint-set! bv offset (pointer-address value)
                           (native-endianness) (sizeof* '*)))
    ((_ bv offset type value)
     (bytevector-uint-set! bv offset value
                           (native-endianness) (sizeof* type)))))

(define-syntax write-types
  (syntax-rules ()
    ((_ bv offset () ())
     #t)
    ((_ bv offset (type0 types ...) (field0 fields ...))
     (begin
       (write-type bv (align offset type0) type0 field0)
       (write-types bv
                    (+ (align offset type0) (type-size type0))
                    (types ...) (fields ...))))))

(define-syntax read-type
  (syntax-rules (~ array quote *)
    ((_ bv offset '*)
     (make-pointer (bytevector-uint-ref bv offset
                                        (native-endianness)
                                        (sizeof* '*))))
    ((_ bv offset (type ~ order))
     (bytevector-uint-ref bv offset
                          (endianness order) (sizeof* type)))
    ((_ bv offset (array type n))
     (unfold (lambda (i) (= i n))
             (lambda (i)
               (read-type bv (+ offset (* i (sizeof* type))) type))
             1+
             0))
    ((_ bv offset type)
     (bytevector-uint-ref bv offset
                          (native-endianness) (sizeof* type)))))

(define-syntax read-types
  (syntax-rules ()
    ((_ return bv offset () (values ...))
     (return values ...))
    ((_ return bv offset (type0 types ...) (values ...))
     (read-types return
                 bv
                 (+ (align offset type0) (type-size type0))
                 (types ...)
                 (values ... (read-type bv
                                        (align offset type0)
                                        type0))))))

(define-syntax define-c-struct-macro
  (syntax-rules ()
    "Define NAME as a macro that can be queried to get information about the C
struct it represents.  In particular:

  (NAME field-offset FIELD)

returns the offset in bytes of FIELD within the C struct represented by NAME."
    ((_ name ((fields types) ...))
     (define-c-struct-macro name
       (fields ...) 0 ()
       ((fields types) ...)))
    ((_ name (fields ...) offset (clauses ...) ((field type) rest ...))
     (define-c-struct-macro name
       (fields ...)
       (+ (align offset type) (type-size type))
       (clauses ... ((_ field-offset field) (align offset type)))
       (rest ...)))
    ((_ name (fields ...) offset (clauses ...) ())
     (define-syntax name
       (syntax-rules (field-offset fields ...)
         clauses ...)))))

(define-syntax define-c-struct
  (syntax-rules ()
    "Define SIZE as the size in bytes of the C structure made of FIELDS.  READ
as a deserializer and WRITE! as a serializer for the C structure with the
given TYPES.  READ uses WRAP-FIELDS to return its value."
    ((_ name size wrap-fields read write! (fields types) ...)
     (begin
       (define-c-struct-macro name
         ((fields types) ...))
       (define size
         (struct-size 0 () types ...))
       (define (write! bv offset fields ...)
         (write-types bv offset (types ...) (fields ...)))
       (define* (read bv #:optional (offset 0))
         (read-types wrap-fields bv offset (types ...) ()))))))

(define-syntax-rule (c-struct-field-offset type field)
  "Return the offset in BYTES of FIELD within TYPE, where TYPE is a C struct
defined with 'define-c-struct' and FIELD is a field identifier.  An
expansion-time error is raised if FIELD does not exist in TYPE."
  (type field-offset field))

\f
;;;
;;; FFI.
;;;

(define (call-with-restart-on-EINTR thunk)
  (let loop ()
    (catch 'system-error
      thunk
      (lambda args
        (if (= (system-error-errno args) EINTR)
            (loop)
            (apply throw args))))))

(define-syntax-rule (restart-on-EINTR expr)
  "Evaluate EXPR and restart upon EINTR.  Return the value of EXPR."
  (call-with-restart-on-EINTR (lambda () expr)))

(define (syscall->procedure return-type name argument-types)
  "Return a procedure that wraps the C function NAME using the dynamic FFI,
and that returns two values: NAME's return value, and errno.

If an error occurs while creating the binding, defer the error report until
the returned procedure is called."
  (catch #t
    (lambda ()
      (let ((ptr (dynamic-func name (dynamic-link))))
        ;; The #:return-errno? facility was introduced in Guile 2.0.12.
        (pointer->procedure return-type ptr argument-types
                            #:return-errno? #t)))
    (lambda args
      (lambda _
        (throw 'system-error name  "~A" (list (strerror ENOSYS))
               (list ENOSYS))))))

(define-syntax define-as-needed
  (syntax-rules ()
    "Define VARIABLE.  If VARIABLE already exists in (guile) then re-export it,
  otherwise export the newly-defined VARIABLE."
    ((_ (proc args ...) body ...)
     (define-as-needed proc (lambda* (args ...) body ...)))
    ((_ variable value)
     (if (module-defined? the-scm-module 'variable)
         (module-re-export! (current-module) '(variable))
         (begin
           (module-define! (current-module) 'variable value)
           (module-export! (current-module) '(variable)))))))

\f
;;;
;;; Block devices.
;;;

;; Convert between major:minor pairs and packed ‘device number’ representation.
;; XXX These aren't syscalls, but if you squint very hard they are part of the
;; FFI or however you want to justify me not finding a better fit… :-)
(define (device-number major minor)     ; see glibc's <sys/sysmacros.h>
  "Return the device number for the device with MAJOR and MINOR, for use as
the last argument of `mknod'."
  (logior (ash (logand #x00000fff major) 8)
          (ash (logand #xfffff000 major) 32)
               (logand #x000000ff minor)
          (ash (logand #xffffff00 minor) 12)))

(define (device-number->major+minor device)     ; see glibc's <sys/sysmacros.h>
  "Return two values: the major and minor device numbers that make up DEVICE."
  (values (logior (ash (logand #x00000000000fff00 device) -8)
                  (ash (logand #xfffff00000000000 device) -32))
          (logior      (logand #x00000000000000ff device)
                  (ash (logand #x00000ffffff00000 device) -12))))

\f
;;;
;;; File systems.
;;;

(define (augment-mtab source target type options)
  "Augment /etc/mtab with information about the given mount point."
  (let ((port (open-file "/etc/mtab" "a")))
    (format port "~a ~a ~a ~a 0 0~%"
            source target type (or options "rw"))
    (close-port port)))

(define (read-mtab port)
  "Read an mtab-formatted file from PORT, returning a list of tuples."
  (let loop ((result '()))
    (let ((line (read-line port)))
      (if (eof-object? line)
          (reverse result)
          (loop (cons (string-tokenize line) result))))))

(define (remove-from-mtab target)
  "Remove mount point TARGET from /etc/mtab."
  (define entries
    (remove (match-lambda
             ((device mount-point type options freq passno)
              (string=? target mount-point))
             (_ #f))
            (call-with-input-file "/etc/mtab" read-mtab)))

  (call-with-output-file "/etc/mtab"
    (lambda (port)
      (for-each (match-lambda
                 ((device mount-point type options freq passno)
                  (format port "~a ~a ~a ~a ~a ~a~%"
                          device mount-point type options freq passno)))
                entries))))

;; Linux mount flags, from libc's <sys/mount.h>.
(define MS_RDONLY             1)
(define MS_NOSUID             2)
(define MS_NODEV              4)
(define MS_NOEXEC             8)
(define MS_REMOUNT           32)
(define MS_NOATIME         1024)
(define MS_BIND            4096)
(define MS_MOVE            8192)
(define MS_RELATIME     2097152)
(define MS_STRICTATIME 16777216)
(define MS_LAZYTIME    33554432)

(define MNT_FORCE       1)
(define MNT_DETACH      2)
(define MNT_EXPIRE      4)
(define UMOUNT_NOFOLLOW 8)

(define-as-needed (mount source target type
                         #:optional (flags 0) options
                         #:key (update-mtab? #f))
  "Mount device SOURCE on TARGET as a file system TYPE.
Optionally, FLAGS may be a bitwise-or of the MS_* <sys/mount.h>
constants, and OPTIONS may be a string.  When FLAGS contains
MS_REMOUNT, SOURCE and TYPE are ignored.  When UPDATE-MTAB? is true,
update /etc/mtab.  Raise a 'system-error' exception on error."
  ;; XXX: '#:update-mtab?' is not implemented by core 'mount'.
  (let ((proc (syscall->procedure int "mount" `(* * * ,unsigned-long *))))
    (let-values (((ret err)
                  (proc (if source
                            (string->pointer source)
                            %null-pointer)
                        (string->pointer target)
                        (if type
                            (string->pointer type)
                            %null-pointer)
                        flags
                        (if options
                            (string->pointer options)
                            %null-pointer))))
      (unless (zero? ret)
        (throw 'system-error "mount" "mount ~S on ~S: ~A"
               (list source target (strerror err))
               (list err)))
      (when update-mtab?
        (augment-mtab source target type options)))))

(define-as-needed (umount target
                          #:optional (flags 0)
                          #:key (update-mtab? #f))
  "Unmount TARGET.  Optionally FLAGS may be one of the MNT_* or UMOUNT_*
constants from <sys/mount.h>."
  ;; XXX: '#:update-mtab?' is not implemented by core 'umount'.
  (let ((proc (syscall->procedure int "umount2" `(* ,int))))
    (let-values (((ret err)
                  (proc (string->pointer target) flags)))
      (unless (zero? ret)
        (throw 'system-error "umount" "~S: ~A"
               (list target (strerror err))
               (list err)))
      (when update-mtab?
        (remove-from-mtab target)))))

;; Mount point information.
(define-record-type <mount>
  (%mount source point devno type options)
  mount?
  (devno    mount-device-number)                  ;st_dev
  (source   mount-source)                         ;string
  (point    mount-point)                          ;string
  (type     mount-type)                           ;string
  (options  mount-options))                       ;string

(define (option-string->mount-flags str)
  "Parse the \"option string\" STR as it appears in /proc/mounts and similar,
and return two values: a mount bitmask (inclusive or of MS_* constants), and
the remaining unprocessed options."
  ;; Why do we need to do this?  Because mount flags and mount options are
  ;; often lumped together; this is the case in /proc/mounts & co., so we need
  ;; to extract the bits that actually correspond to mount flags.

  (define not-comma
    (char-set-complement (char-set #\,)))

  (define lst
    (string-tokenize str not-comma))

  (let loop ((options   lst)
             (mask      0)
             (remainder '()))
    (match options
      (()
       (values mask (string-concatenate-reverse remainder)))
      ((head . tail)
       (letrec-syntax ((match-options (syntax-rules (=>)
                                        ((_)
                                         (loop tail mask
                                               (cons head remainder)))
                                        ((_ (str => bit) rest ...)
                                         (if (string=? str head)
                                             (loop tail (logior bit mask)
                                                   remainder)
                                             (match-options rest ...))))))
         (match-options ("rw"         => 0)
                        ("ro"         => MS_RDONLY)
                        ("nosuid"     => MS_NOSUID)
                        ("nodev"      => MS_NODEV)
                        ("noexec"     => MS_NOEXEC)
                        ("relatime"   => MS_RELATIME)
                        ("noatime"    => MS_NOATIME)))))))

(define (mount-flags mount)
  "Return the mount flags of MOUNT, a <mount> record, as an inclusive or of
MS_* constants."
  (option-string->mount-flags (mount-options mount)))

(define (octal-decode str)
  "Decode octal escapes from STR and return the corresponding string.  STR may
look like this: \"white\\040space\", which is decoded as \"white space\"."
  (define char-set:octal
    (char-set #\0 #\1 #\2 #\3 #\4 #\5 #\6 #\7))
  (define (octal? c)
    (char-set-contains? char-set:octal c))

  (let loop ((chars (string->list str))
             (result '()))
    (match chars
      (()
       (list->string (reverse result)))
      ((#\\ (? octal? a) (? octal? b) (? octal? c) . rest)
       (loop rest
             (cons (integer->char
                    (string->number (list->string (list a b c)) 8))
                   result)))
      ((head . tail)
       (loop tail (cons head result))))))

(define (mounts)
  "Return the list of mounts (<mount> records) visible in the namespace of the
current process."
  (define (string->device-number str)
    (match (string-split str #\:)
      (((= string->number major) (= string->number minor))
       (device-number major minor))))

  (call-with-input-file "/proc/self/mountinfo"
    (lambda (port)
      (let loop ((result '()))
        (let ((line (read-line port)))
          (if (eof-object? line)
              (reverse result)
              (match (string-tokenize line)
                ;; See the proc(5) man page for a description of the columns.
                ((id parent-id major:minor root mount-point
                     options _ ... "-" type source _)
                 (let ((devno (string->device-number major:minor)))
                   (loop (cons (%mount (octal-decode source)
                                       (octal-decode mount-point)
                                       devno type options)
                               result)))))))))))

(define (mount-points)
  "Return the mounts points for currently mounted file systems."
  (map mount-point (mounts)))

(define swapon
  (let ((proc (syscall->procedure int "swapon" (list '* int))))
    (lambda* (device #:optional (flags 0))
      "Use the block special device at DEVICE for swapping."
      (let-values (((ret err)
                    (proc (string->pointer device) flags)))
        (unless (zero? ret)
          (throw 'system-error "swapon" "~S: ~A"
                 (list device (strerror err))
                 (list err)))))))

(define swapoff
  (let ((proc (syscall->procedure int "swapoff" '(*))))
    (lambda (device)
      "Stop using block special device DEVICE for swapping."
      (let-values (((ret err) (proc (string->pointer device))))
        (unless (zero? ret)
          (throw 'system-error "swapoff" "~S: ~A"
                 (list device (strerror err))
                 (list err)))))))

(define-as-needed RB_AUTOBOOT    #x01234567)
(define-as-needed RB_HALT_SYSTEM #xcdef0123)
(define-as-needed RB_ENABLED_CAD #x89abcdef)
(define-as-needed RB_DISABLE_CAD 0)
(define-as-needed RB_POWER_OFF   #x4321fedc)
(define-as-needed RB_SW_SUSPEND  #xd000fce2)
(define-as-needed RB_KEXEC       #x45584543)

(define-as-needed (reboot #:optional (cmd RB_AUTOBOOT))
  (let ((proc (syscall->procedure int "reboot" (list int))))
    (let-values (((ret err) (proc cmd)))
      (unless (zero? ret)
        (throw 'system-error "reboot" "~S: ~A"
               (list cmd (strerror err))
               (list err))))))

(define-as-needed (load-linux-module data #:optional (options ""))
  (let ((proc (syscall->procedure int "init_module"
                                  (list '* unsigned-long '*))))
    (let-values (((ret err)
                  (proc (bytevector->pointer data)
                        (bytevector-length data)
                        (string->pointer options))))
      (unless (zero? ret)
        (throw 'system-error "load-linux-module" "~A"
               (list (strerror err))
               (list err))))))

(define (kernel? pid)
  "Return #t if PID designates a \"kernel thread\" rather than a normal
user-land process."
  (let ((stat (call-with-input-file (format #f "/proc/~a/stat" pid)
                (compose string-tokenize read-string))))
    ;; See proc.txt in Linux's documentation for the list of fields.
    (match stat
      ((pid tcomm state ppid pgrp sid tty_nr tty_pgrp flags min_flt
            cmin_flt maj_flt cmaj_flt utime stime cutime cstime
            priority nice num_thread it_real_value start_time
            vsize rss rsslim
            (= string->number start_code) (= string->number end_code) _ ...)
       ;; Got this obscure trick from sysvinit's 'killall5' program.
       (and (zero? start_code) (zero? end_code))))))

(define (processes)
  "Return the list of live processes."
  (sort (filter-map (lambda (file)
                      (let ((pid (string->number file)))
                        (and pid
                             (not (kernel? pid))
                             pid)))
                    (scandir "/proc"))
        <))

(define mkdtemp!
  (let ((proc (syscall->procedure '* "mkdtemp" '(*))))
    (lambda (tmpl)
      "Create a new unique directory in the file system using the template
string TMPL and return its file name.  TMPL must end with 'XXXXXX'."
      (let-values (((result err) (proc (string->pointer tmpl))))
        (when (null-pointer? result)
          (throw 'system-error "mkdtemp!" "~S: ~A"
                 (list tmpl (strerror err))
                 (list err)))
        (pointer->string result)))))

(define fdatasync
  (let ((proc (syscall->procedure int "fdatasync" (list int))))
    (lambda (port)
      "Flush buffered output of PORT, an output file port, and then call
fdatasync(2) on the underlying file descriptor."
      (force-output port)
      (let*-values (((fd)      (fileno port))
                    ((ret err) (proc fd)))
        (unless (zero? ret)
          (throw 'system-error "fdatasync" "~S: ~A"
                 (list fd (strerror err))
                 (list err)))))))


(define-record-type <file-system>
  (file-system type block-size blocks blocks-free
               blocks-available files free-files identifier
               name-length fragment-size mount-flags spare)
  file-system?
  (type              file-system-type)
  (block-size        file-system-block-size)
  (blocks            file-system-block-count)
  (blocks-free       file-system-blocks-free)
  (blocks-available  file-system-blocks-available)
  (files             file-system-file-count)
  (free-files        file-system-free-file-nodes)
  (identifier        file-system-identifier)
  (name-length       file-system-maximum-name-length)
  (fragment-size     file-system-fragment-size)
  (mount-flags       file-system-mount-flags)
  (spare             file-system--spare))

(define-syntax fsword                             ;fsword_t
  (identifier-syntax long))

(define linux? (string-contains %host-type "linux-gnu"))

(define-syntax define-statfs-flags
  (syntax-rules (linux hurd)
    "Define the statfs mount flags."
    ((_ (name (linux linux-value) (hurd hurd-value)) rest ...)
     (begin
       (define name
         (if linux? linux-value hurd-value))
       (define-statfs-flags rest ...)))
    ((_ (name value) rest ...)
     (begin
       (define name value)
       (define-statfs-flags rest ...)))
    ((_) #t)))

(define-statfs-flags                              ;<bits/statfs.h>
  (ST_RDONLY      1)
  (ST_NOSUID      2)
  (ST_NODEV       (linux 4) (hurd 0))
  (ST_NOEXEC      8)
  (ST_SYNCHRONOUS 16)
  (ST_MANDLOCK    (linux 64) (hurd 0))
  (ST_WRITE       (linux 128) (hurd 0))
  (ST_APPEND      (linux 256) (hurd 0))
  (ST_IMMUTABLE   (linux 512) (hurd 0))
  (ST_NOATIME     (linux 1024) (hurd 32))
  (ST_NODIRATIME  (linux 2048) (hurd 0))
  (ST_RELATIME    (linux 4096) (hurd 64)))

(define (statfs-flags->mount-flags flags)
  "Convert FLAGS, a logical or of ST_* constants as returned by
'file-system-mount-flags', to the corresponding logical or of MS_* constants."
  (letrec-syntax ((match-flags (syntax-rules (=>)
                                 ((_ (statfs => mount) rest ...)
                                  (logior (if (zero? (logand flags statfs))
                                              0
                                              mount)
                                          (match-flags rest ...)))
                                 ((_)
                                  0))))
    (match-flags
     (ST_RDONLY     => MS_RDONLY)
     (ST_NOSUID     => MS_NOSUID)
     (ST_NODEV      => MS_NODEV)
     (ST_NOEXEC     => MS_NOEXEC)
     (ST_NOATIME    => MS_NOATIME)
     (ST_NODIRATIME => 0)                         ;FIXME
     (ST_RELATIME   => MS_RELATIME))))

(define-c-struct %statfs                          ;<bits/statfs.h>
  sizeof-statfs                                   ;slightly overestimated
  file-system
  read-statfs
  write-statfs!
  (type             fsword)
  (block-size       fsword)
  (blocks           uint64)
  (blocks-free      uint64)
  (blocks-available uint64)
  (files            uint64)
  (free-files       uint64)
  (identifier       (array int 2))
  (name-length      fsword)
  (fragment-size    fsword)
  (mount-flags      fsword)                       ;ST_*
  (spare            (array fsword 4)))

(define statfs
  (let ((proc (syscall->procedure int "statfs64" '(* *))))
    (lambda (file)
      "Return a <file-system> data structure describing the file system
mounted at FILE."
      (let*-values (((stat)    (make-bytevector sizeof-statfs))
                    ((ret err) (proc (string->pointer file)
                                     (bytevector->pointer stat))))
        (if (zero? ret)
            (read-statfs stat)
            (throw 'system-error "statfs" "~A: ~A"
                   (list file (strerror err))
                   (list err)))))))

(define (free-disk-space file)
  "Return the free disk space, in bytes, on the file system that hosts FILE."
  (let ((fs (statfs file)))
    (* (file-system-block-size fs)
       (file-system-blocks-available fs))))

;; Flags for the *at command, notably the 'utime' procedure of libguile.
;; From <fcntl.h>.
(define-as-needed AT_FDCWD             -100)
(define-as-needed AT_SYMLINK_NOFOLLOW #x100)
(define-as-needed AT_REMOVEDIR        #x200)
(define-as-needed AT_SYMLINK_FOLLOW   #x400)
(define-as-needed AT_NO_AUTOMOUNT     #x800)
(define-as-needed AT_EMPTY_PATH       #x1000)

(define-syntax BLKRRPART                         ;<sys/mount.h>
  (identifier-syntax #x125F))

(define* (device-in-use? device)
  "Return #t if the block DEVICE is in use, #f otherwise. This is inspired
from fdisk_device_is_used function of util-linux. This is particularly useful
for devices that do not appear in /proc/self/mounts like overlayfs lowerdir
backend device."
  (let*-values (((fd)      (open-fdes device O_RDONLY))
                ((ret err) (%ioctl fd BLKRRPART %null-pointer)))
    (close-fdes fd)
    (cond
     ((= ret 0)
      #f)
     ((= err EBUSY)
      #t)
     ((= err EINVAL)
      ;; We get EINVAL for devices that have the GENHD_FL_NO_PART_SCAN flag
      ;; set in the kernel, in particular loopback devices, though we do seem
      ;; to get it for SCSI storage (/dev/sr0) on QEMU.
      #f)
     (else
      (throw 'system-error "ioctl" "~A"
             (list (strerror err))
             (list err))))))

(define getxattr
  (let ((proc (syscall->procedure ssize_t "getxattr"
                                  `(* * * ,size_t))))
    (lambda (file key)
      "Get the extended attribute value for KEY on FILE."
      (let-values (((size err)
                    ;; Get size of VALUE for buffer.
                    (proc (string->pointer/utf-8 file)
                          (string->pointer key)
                          (string->pointer "")
                          0)))
        (cond ((< size 0) #f)
              ((zero? size) "")
              ;; Get VALUE in buffer of SIZE.  XXX actual size can race.
              (else (let*-values (((buf) (make-bytevector size))
                                  ((size err)
                                   (proc (string->pointer/utf-8 file)
                                         (string->pointer key)
                                         (bytevector->pointer buf)
                                         size)))
                      (if (>= size 0)
                          (utf8->string buf)
                          (throw 'system-error "getxattr" "~S: ~A"
                                 (list file key (strerror err))
                                 (list err))))))))))

(define setxattr
  (let ((proc (syscall->procedure int "setxattr"
                                  `(* * * ,size_t ,int))))
    (lambda* (file key value #:optional (flags 0))
      "Set extended attribute KEY to VALUE on FILE."
      (let*-values (((bv) (string->utf8 value))
                    ((ret err)
                     (proc (string->pointer/utf-8 file)
                           (string->pointer key)
                           (bytevector->pointer bv)
                           (bytevector-length bv)
                           flags)))
        (unless (zero? ret)
          (throw 'system-error "setxattr" "~S: ~A"
                 (list file key value (strerror err))
                 (list err)))))))

\f
;;;
;;; Random.
;;;

;; From <uapi/linux/random.h>.
(define RNDADDTOENTCNT
  ;; Avoid using %current-system here to avoid depending on host-side code.
  (if (string-prefix? "powerpc64le" %host-type)
      #x80045201
      #x40045201))

(define (add-to-entropy-count port-or-fd n)
  "Add N to the kernel's entropy count (the value that can be read from
/proc/sys/kernel/random/entropy_avail).  PORT-OR-FD must correspond to
/dev/urandom or /dev/random.  Raise to 'system-error with EPERM when the
caller lacks root privileges."
  (let ((fd  (if (port? port-or-fd)
                 (fileno port-or-fd)
                 port-or-fd))
        (box (make-bytevector (sizeof int))))
    (bytevector-sint-set! box 0 n (native-endianness)
                          (sizeof int))
    (let-values (((ret err)
                  (%ioctl fd RNDADDTOENTCNT
                          (bytevector->pointer box))))
      (unless (zero? err)
        (throw 'system-error "add-to-entropy-count" "~A"
               (list (strerror err))
               (list err))))))

\f
;;;
;;; Containers.
;;;

;; Linux clone flags, from linux/sched.h
(define CLONE_CHILD_CLEARTID #x00200000)
(define CLONE_CHILD_SETTID   #x01000000)
(define CLONE_NEWNS          #x00020000)
(define CLONE_NEWUTS         #x04000000)
(define CLONE_NEWIPC         #x08000000)
(define CLONE_NEWUSER        #x10000000)
(define CLONE_NEWPID         #x20000000)
(define CLONE_NEWNET         #x40000000)

(define %set-automatic-finalization-enabled?!
  ;; When using a statically-linked Guile, for instance in the initrd, we
  ;; cannot resolve this symbol, but most of the time we don't need it
  ;; anyway.  Thus, delay it.
  (let ((proc (delay
                (pointer->procedure int
                                    (dynamic-func
                                     "scm_set_automatic_finalization_enabled"
                                     (dynamic-link))
                                    (list int)))))
    (lambda (enabled?)
      "Switch on or off automatic finalization in a separate thread.
Turning finalization off shuts down the finalization thread as a side effect."
      (->bool ((force proc) (if enabled? 1 0))))))

(define-syntax-rule (without-automatic-finalization exp)
  "Turn off automatic finalization within the dynamic extent of EXP."
  (let ((enabled? #t))
    (dynamic-wind
      (lambda ()
        (set! enabled? (%set-automatic-finalization-enabled?! #f)))
      (lambda ()
        exp)
      (lambda ()
        (%set-automatic-finalization-enabled?! enabled?)))))

;; The libc interface to sys_clone is not useful for Scheme programs, so the
;; low-level system call is wrapped instead.  The 'syscall' function is
;; declared in <unistd.h> as a variadic function; in practice, it expects 6
;; pointer-sized arguments, as shown in, e.g., x86_64/syscall.S.
(define clone
  (let* ((proc (syscall->procedure int "syscall"
                                   (list long                   ;sysno
                                         unsigned-long          ;flags
                                         '* '* '*
                                         '*)))
         ;; TODO: Don't do this.
         (syscall-id (match (utsname:machine (uname))
                       ("i686"   120)
                       ("x86_64" 56)
                       ("mips64" 5055)
                       ("armv7l" 120)
                       ("aarch64" 220)
                       ("ppc64le" 120)
                       (_ #f))))
    (lambda (flags)
      "Create a new child process by duplicating the current parent process.
Unlike the fork system call, clone accepts FLAGS that specify which resources
are shared between the parent and child processes."
      (let-values (((ret err)
                    ;; Guile 2.2 runs a finalization thread.  'primitive-fork'
                    ;; takes care of shutting it down before forking, and we
                    ;; must do the same here.  Failing to do that, if the
                    ;; child process calls 'primitive-fork', it will hang
                    ;; while trying to pthread_join the finalization thread
                    ;; since that thread does not exist.
                    (without-automatic-finalization
                     (proc syscall-id flags
                           %null-pointer              ;child stack
                           %null-pointer %null-pointer ;ptid & ctid
                           %null-pointer))))           ;unused
        (if (= ret -1)
            (throw 'system-error "clone" "~d: ~A"
                   (list flags (strerror err))
                   (list err))
            ret)))))

(define setns
  ;; Some systems may be using an old (pre-2.14) version of glibc where there
  ;; is no 'setns' function available.
  (false-if-exception
   (let ((proc (syscall->procedure int "setns" (list int int))))
     (lambda (fdes nstype)
       "Reassociate the current process with the namespace specified by FDES, a
file descriptor obtained by opening a /proc/PID/ns/* file.  NSTYPE specifies
which type of namespace the current process may be reassociated with, or 0 if
there is no such limitation."
       (let-values (((ret err) (proc fdes nstype)))
         (unless (zero? ret)
           (throw 'system-error "setns" "~d ~d: ~A"
                  (list fdes nstype (strerror err))
                  (list err))))))))

(define pivot-root
  (let ((proc (syscall->procedure int "pivot_root" (list '* '*))))
    (lambda (new-root put-old)
      "Change the root file system to NEW-ROOT and move the current root file
system to PUT-OLD."
      (let-values (((ret err)
                    (proc (string->pointer new-root)
                          (string->pointer put-old))))
        (unless (zero? ret)
          (throw 'system-error "pivot_root" "~S ~S: ~A"
                 (list new-root put-old (strerror err))
                 (list err)))))))

\f
;;;
;;; Opendir & co.
;;;

(define (file-type->symbol type)
  ;; Convert TYPE to symbols like 'stat:type' does.
  (cond ((= type DT_REG)  'regular)
        ((= type DT_LNK)  'symlink)
        ((= type DT_DIR)  'directory)
        ((= type DT_FIFO) 'fifo)
        ((= type DT_CHR)  'char-special)
        ((= type DT_BLK)  'block-special)
        ((= type DT_SOCK) 'socket)
        (else             'unknown)))

;; 'struct dirent64' for GNU/Linux.
(define-c-struct %struct-dirent-header/linux
  sizeof-dirent-header/linux
  (lambda (inode offset length type name)
    `((type . ,(file-type->symbol type))
      (inode . ,inode)))
  read-dirent-header/linux
  write-dirent-header!/linux
  (inode  int64)
  (offset int64)
  (length unsigned-short)
  (type   uint8)
  (name   uint8))                                 ;first byte of 'd_name'

;; 'struct dirent64' for GNU/Hurd.
(define-c-struct %struct-dirent-header/hurd
  sizeof-dirent-header/hurd
  (lambda (inode length type name-length name)
    `((type . ,(file-type->symbol type))
      (inode . ,inode)))
  read-dirent-header/hurd
  write-dirent-header!/hurd
  (inode   int64)
  (length  unsigned-short)
  (type    uint8)
  (namelen uint8)
  (name    uint8))

;; Constants for the 'type' field, from <dirent.h>.
(define DT_UNKNOWN 0)
(define DT_FIFO 1)
(define DT_CHR 2)
(define DT_DIR 4)
(define DT_BLK 6)
(define DT_REG 8)
(define DT_LNK 10)
(define DT_SOCK 12)
(define DT_WHT 14)

(define string->pointer/utf-8
  (cut string->pointer <> "UTF-8"))

(define pointer->string/utf-8
  (cut pointer->string <> <> "UTF-8"))

(define opendir*
  (let ((proc (syscall->procedure '* "opendir" '(*))))
    (lambda* (name #:optional (string->pointer string->pointer/utf-8))
      (let-values (((ptr err)
                    (proc (string->pointer name))))
        (if (null-pointer? ptr)
            (throw 'system-error "opendir*"
                   "~A: ~A" (list name (strerror err))
                   (list err))
            ptr)))))

(define closedir*
  (let ((proc (syscall->procedure int "closedir" '(*))))
    (lambda (directory)
      (let-values (((ret err)
                    (proc directory)))
        (unless (zero? ret)
          (throw 'system-error "closedir"
                 "closedir: ~A" (list (strerror err))
                 (list err)))))))

(define (readdir-procedure name-field-offset sizeof-dirent-header
                           read-dirent-header)
  (let ((proc (syscall->procedure '* "readdir64" '(*))))
    (lambda* (directory #:optional (pointer->string pointer->string/utf-8))
      (let ((ptr (proc directory)))
        (and (not (null-pointer? ptr))
             (cons (pointer->string
                    (make-pointer (+ (pointer-address ptr) name-field-offset))
                    -1)
                   (read-dirent-header
                    (pointer->bytevector ptr sizeof-dirent-header))))))))

(define readdir*
  ;; Decide at run time which one must be used.
  (if (string-contains %host-type "linux-gnu")
      (readdir-procedure (c-struct-field-offset %struct-dirent-header/linux
                                                name)
                         sizeof-dirent-header/linux
                         read-dirent-header/linux)
      (readdir-procedure (c-struct-field-offset %struct-dirent-header/hurd
                                                name)
                         sizeof-dirent-header/hurd
                         read-dirent-header/hurd)))

(define* (scandir* name #:optional
                   (select? (const #t))
                   (entry<? (lambda (entry1 entry2)
                              (match entry1
                                ((name1 . _)
                                 (match entry2
                                   ((name2 . _)
                                    (string<? name1 name2)))))))
                   #:key
                   (string->pointer string->pointer/utf-8)
                   (pointer->string pointer->string/utf-8))
  "This procedure improves on Guile's 'scandir' procedure in several ways:

   1. Systematically encode decode file names using STRING->POINTER and
      POINTER->STRING (UTF-8 by default; this works around a defect in Guile 2.0/2.2
      where 'scandir' decodes file names according to the current locale, which is
      not always desirable.

   2. Each entry that is returned has the form (NAME . PROPERTIES).
      PROPERTIES is an alist showing additional properties about the entry, as
      found in 'struct dirent'.  An entry may look like this:

        (\"foo.scm\" (type . regular) (inode . 123456))

      Callers must be prepared to deal with the case where 'type' is 'unknown'
      since some file systems do not provide that information.

   3. Raise to 'system-error' when NAME cannot be opened."
  (let ((directory (opendir* name string->pointer)))
    (dynamic-wind
      (const #t)
      (lambda ()
        (let loop ((result '()))
          (match (readdir* directory pointer->string)
            (#f
             (sort result entry<?))
            (entry
             (loop (if (select? entry)
                       (cons entry result)
                       result))))))
      (lambda ()
        (closedir* directory)))))

\f
;;;
;;; Advisory file locking.
;;;

(define-c-struct %struct-flock                    ;<fcntl.h>
  sizeof-flock
  list
  read-flock
  write-flock!
  (type   short)
  (whence short)
  (start  size_t)
  (length size_t)
  (pid    int))

(define F_SETLKW
  ;; On Linux-based systems, this is usually 7, but not always
  ;; (exceptions include SPARC.)  On GNU/Hurd, it's 9.
  (cond ((string-contains %host-type "sparc") 9)  ; sparc-*-linux-gnu
        ((string-contains %host-type "linux") 7)  ; *-linux-gnu
        (else 9)))                                ; *-gnu*

(define F_SETLK
  ;; Likewise: GNU/Hurd and SPARC use 8, while the others typically use 6.
  (cond ((string-contains %host-type "sparc") 8)  ; sparc-*-linux-gnu
        ((string-contains %host-type "linux") 6)  ; *-linux-gnu
        (else 8)))                                ; *-gnu*

(define F_xxLCK
  ;; The F_RDLCK, F_WRLCK, and F_UNLCK constants.
  (cond ((string-contains %host-type "sparc") #(1 2 3))    ; sparc-*-linux-gnu
        ((string-contains %host-type "hppa")  #(1 2 3))    ; hppa-*-linux-gnu
        ((string-contains %host-type "linux") #(0 1 2))    ; *-linux-gnu
        (else                                 #(1 2 3))))  ; *-gnu*

(define fcntl-flock
  (let ((proc (syscall->procedure int "fcntl" `(,int ,int *))))
    (lambda* (fd-or-port operation #:key (wait? #t))
      "Perform locking OPERATION on the file beneath FD-OR-PORT.  OPERATION
must be a symbol, one of 'read-lock, 'write-lock, or 'unlock.  When WAIT? is
true, block until the lock is acquired; otherwise, thrown an 'flock-error'
exception if it's already taken."
      (define (operation->int op)
        (case op
          ((read-lock)  (vector-ref F_xxLCK 0))
          ((write-lock) (vector-ref F_xxLCK 1))
          ((unlock)     (vector-ref F_xxLCK 2))
          (else         (error "invalid fcntl-flock operation" op))))

      (define fd
        (if (port? fd-or-port)
            (fileno fd-or-port)
            fd-or-port))

      (define bv
        (make-bytevector sizeof-flock))

      (write-flock! bv 0
                    (operation->int operation) SEEK_SET
                    0 0                           ;whole file
                    0)

      ;; XXX: 'fcntl' is a vararg function, but here we happily use the
      ;; standard ABI; crossing fingers.
      (let-values (((ret err)
                    (proc fd
                          (if wait?
                              F_SETLKW            ;lock & wait
                              F_SETLK)            ;non-blocking attempt
                          (bytevector->pointer bv))))
        (unless (zero? ret)
          ;; Presumably we got EAGAIN or so.
          (throw 'flock-error err))))))

(define* (lock-file file #:key (wait? #t))
  "Wait and acquire an exclusive lock on FILE.  Return an open port."
  (let ((port (open-file file "w0")))
    (fcntl-flock port 'write-lock #:wait? wait?)
    port))

(define (unlock-file port)
  "Unlock PORT, a port returned by 'lock-file'."
  (fcntl-flock port 'unlock)
  (close-port port)
  #t)

(define (call-with-file-lock file thunk)
  (let ((port #f))
    (dynamic-wind
      (lambda ()
        (set! port
          (catch 'system-error
            (lambda ()
              (lock-file file))
            (lambda args
              ;; When using the statically-linked Guile in the initrd,
              ;; 'fcntl-flock' returns ENOSYS unconditionally.  Ignore
              ;; that error since we're typically the only process running
              ;; at this point.
              (if (= ENOSYS (system-error-errno args))
                  #f
                  (apply throw args))))))
      thunk
      (lambda ()
        (when port
          (unlock-file port))))))

(define (call-with-file-lock/no-wait file thunk handler)
  (let ((port #f))
    (dynamic-wind
      (lambda ()
        (set! port
          (catch #t
            (lambda ()
              (lock-file file #:wait? #f))
            (lambda (key . args)
              (match key
                ('flock-error
                 (apply handler args)
                 ;; No open port to the lock, so return #f.
                 #f)
                ('system-error
                 ;; When using the statically-linked Guile in the initrd,
                 ;; 'fcntl-flock' returns ENOSYS unconditionally.  Ignore
                 ;; that error since we're typically the only process running
                 ;; at this point.
                 (if (= ENOSYS (system-error-errno (cons key args)))
                     #f
                     (apply throw key args)))
                (_ (apply throw key args)))))))
      thunk
      (lambda ()
        (when port
          (unlock-file port))))))

(define-syntax-rule (with-file-lock file exp ...)
  "Wait to acquire a lock on FILE and evaluate EXP in that context."
  (call-with-file-lock file (lambda () exp ...)))

(define-syntax-rule (with-file-lock/no-wait file handler exp ...)
  "Try to acquire a lock on FILE and evaluate EXP in that context.  Execute
handler if the lock is already held by another process."
  (call-with-file-lock/no-wait file (lambda () exp ...) handler))

\f
;;;
;;; Miscellaneous, aka. 'prctl'.
;;;

(define %prctl
  ;; Should it win the API contest against 'ioctl'?  You tell us!
  (syscall->procedure int "prctl"
                      (list int unsigned-long unsigned-long
                            unsigned-long unsigned-long)))

(define PR_SET_NAME 15)                           ;<linux/prctl.h>
(define PR_GET_NAME 16)

(define %max-thread-name-length
  ;; Maximum length in bytes of the process name, including the terminating
  ;; zero.
  16)

(define (set-thread-name!/linux name)
  "Set the name of the calling thread to NAME.  NAME is truncated to 15
bytes."
  (let ((ptr (string->pointer name)))
    (let-values (((ret err)
                  (%prctl PR_SET_NAME
                          (pointer-address ptr) 0 0 0)))
      (unless (zero? ret)
        (throw 'set-process-name "set-process-name"
               "set-process-name: ~A"
               (list (strerror err))
               (list err))))))

(define (thread-name/linux)
  "Return the name of the calling thread as a string."
  (let ((buf (make-bytevector %max-thread-name-length)))
    (let-values (((ret err)
                  (%prctl PR_GET_NAME
                          (pointer-address (bytevector->pointer buf))
                          0 0 0)))
      (if (zero? ret)
          (bytes->string (bytevector->u8-list buf))
          (throw 'process-name "process-name"
                 "process-name: ~A"
                 (list (strerror err))
                 (list err))))))

(define set-thread-name
  (if (string-contains %host-type "linux")
      set-thread-name!/linux
      (const #f)))

(define thread-name
  (if (string-contains %host-type "linux")
      thread-name/linux
      (const "")))

\f
;;;
;;; Network interfaces.
;;;

(define SIOCGIFCONF                               ;from <bits/ioctls.h>
                                                  ;     <net/if.h>
                                                  ;     <hurd/ioctl.h>
  (if (string-contains %host-type "linux")
      #x8912                                      ;GNU/Linux
      #xf00801a4))                                ;GNU/Hurd
(define SIOCGIFFLAGS
  (if (string-contains %host-type "linux")
      #x8913                                      ;GNU/Linux
      #xc4804191))                                ;GNU/Hurd
(define SIOCSIFFLAGS
  (if (string-contains %host-type "linux")
      #x8914                                      ;GNU/Linux
      #x84804190))                                ;GNU/Hurd
(define SIOCGIFADDR
  (if (string-contains %host-type "linux")
      #x8915                                      ;GNU/Linux
      #xc08401a1))                                ;GNU/Hurd
(define SIOCSIFADDR
  (if (string-contains %host-type "linux")
      #x8916                                      ;GNU/Linux
      #x8084018c))                                ;GNU/Hurd
(define SIOCGIFNETMASK
  (if (string-contains %host-type "linux")
      #x891b                                      ;GNU/Linux
      #xc08401a5))                                ;GNU/Hurd
(define SIOCSIFNETMASK
  (if (string-contains %host-type "linux")
      #x891c                                      ;GNU/Linux
      #x80840196))                                ;GNU/Hurd
(define SIOCADDRT
  (if (string-contains %host-type "linux")
      #x890B                                      ;GNU/Linux
      -1))                                        ;FIXME: GNU/Hurd?
(define SIOCDELRT
  (if (string-contains %host-type "linux")
      #x890C                                      ;GNU/Linux
      -1))                                        ;FIXME: GNU/Hurd?

;; Flags and constants from <net/if.h>.

(define-as-needed IFF_UP #x1)                     ;Interface is up
(define-as-needed IFF_BROADCAST #x2)              ;Broadcast address valid.
(define-as-needed IFF_LOOPBACK #x8)               ;Is a loopback net.
(define-as-needed IFF_RUNNING #x40)               ;interface RFC2863 OPER_UP
(define-as-needed IFF_NOARP #x80)                 ;ARP disabled or unsupported

(define IF_NAMESIZE 16)                           ;maximum interface name size

(define-c-struct %ifconf-struct
  sizeof-ifconf
  list
  read-ifconf
  write-ifconf!
  (length  int)                                   ;int ifc_len
  (request '*))                                   ;struct ifreq *ifc_ifcu

(define ifreq-struct-size
  ;; 'struct ifreq' begins with an array of IF_NAMESIZE bytes containing the
  ;; interface name (nul-terminated), followed by a bunch of stuff.  This is
  ;; its size in bytes.
  (if (= 8 (sizeof '*))
      40
      32))

(define-c-struct sockaddr-in/linux                ;<linux/in.h>
  sizeof-sockaddr-in/linux
  (lambda (family port address)
    (make-socket-address family address port))
  read-sockaddr-in/linux
  write-sockaddr-in!/linux
  (family    unsigned-short)
  (port      (int16 ~ big))
  (address   (int32 ~ big)))

(define-c-struct sockaddr-in/hurd                 ;<netinet/in.h>
  sizeof-sockaddr-in/hurd
  (lambda (len family port address zero)
    (make-socket-address family address port))
  read-sockaddr-in/hurd
  write-sockaddr-in!/hurd
  (len       uint8)
  (family    uint8)
  (port      (int16 ~ big))
  (address   (int32 ~ big))
  (zero      (array uint8 8)))

(define-c-struct sockaddr-in6/linux               ;<linux/in6.h>
  sizeof-sockaddr-in6/linux
  (lambda (family port flowinfo address scopeid)
    (make-socket-address family address port flowinfo scopeid))
  read-sockaddr-in6/linux
  write-sockaddr-in6!/linux
  (family    unsigned-short)
  (port      (int16 ~ big))
  (flowinfo  (int32 ~ big))
  (address   (int128 ~ big))
  (scopeid   int32))

(define-c-struct sockaddr-in6/hurd                ;<netinet/in.h>
  sizeof-sockaddr-in6/hurd
  (lambda (len family port flowinfo address scopeid)
    (make-socket-address family address port flowinfo scopeid))
  read-sockaddr-in6/hurd
  write-sockaddr-in6!/hurd
  (len       uint8)
  (family    uint8)
  (port      (int16 ~ big))
  (flowinfo  (int32 ~ big))
  (address   (int128 ~ big))
  (scopeid   int32))

(define (write-socket-address!/linux sockaddr bv index)
  "Write SOCKADDR, a socket address as returned by 'make-socket-address', to
bytevector BV at INDEX."
  (let ((family (sockaddr:fam sockaddr)))
    (cond ((= family AF_INET)
           (write-sockaddr-in!/linux bv index
                                     family
                                     (sockaddr:port sockaddr)
                                     (sockaddr:addr sockaddr)))
          ((= family AF_INET6)
           (write-sockaddr-in6!/linux bv index
                                      family
                                      (sockaddr:port sockaddr)
                                      (sockaddr:flowinfo sockaddr)
                                      (sockaddr:addr sockaddr)
                                      (sockaddr:scopeid sockaddr)))
          (else
           (error "unsupported socket address" sockaddr)))))

(define (write-socket-address!/hurd sockaddr bv index)
  "Write SOCKADDR, a socket address as returned by 'make-socket-address', to
bytevector BV at INDEX."
  (let ((family (sockaddr:fam sockaddr)))
    (cond ((= family AF_INET)
           (write-sockaddr-in!/hurd bv index
                                    sizeof-sockaddr-in/hurd
                                    family
                                    (sockaddr:port sockaddr)
                                    (sockaddr:addr sockaddr)
                                    '(0 0 0 0 0 0 0 0)))
          ((= family AF_INET6)
           (write-sockaddr-in6!/hurd bv index
                                     sizeof-sockaddr-in6/hurd
                                     family
                                     (sockaddr:port sockaddr)
                                     (sockaddr:flowinfo sockaddr)
                                     (sockaddr:addr sockaddr)
                                     (sockaddr:scopeid sockaddr)))
          (else
           (error "unsupported socket address" sockaddr)))))

(define write-socket-address!
  (if (string-contains %host-type "linux-gnu")
      write-socket-address!/linux
      write-socket-address!/hurd))

(define PF_PACKET 17)                             ;<bits/socket.h>
(define AF_PACKET PF_PACKET)

(define* (read-socket-address/linux bv #:optional (index 0))
  "Read a socket address from bytevector BV at INDEX."
  (let ((family (bytevector-u16-native-ref bv index)))
    (cond ((= family AF_INET)
           (read-sockaddr-in/linux bv index))
          ((= family AF_INET6)
           (read-sockaddr-in6/linux bv index))
          (else
           ;; XXX: Unsupported address family, such as AF_PACKET.  Return a
           ;; vector such that the vector can at least call 'sockaddr:fam'.
           (vector family)))))

(define* (read-socket-address/hurd bv #:optional (index 0))
  "Read a socket address from bytevector BV at INDEX."
  (let ((family (bytevector-u16-native-ref bv index)))
    (cond ((= family AF_INET)
           (read-sockaddr-in/hurd bv index))
          ((= family AF_INET6)
           (read-sockaddr-in6/hurd bv index))
          (else
           ;; XXX: Unsupported address family, such as AF_PACKET.  Return a
           ;; vector such that the vector can at least call 'sockaddr:fam'.
           (vector family)))))

(define read-socket-address
  (if (string-contains %host-type "linux-gnu")
      read-socket-address/linux
      read-socket-address/hurd))

(define %ioctl
  ;; The most terrible interface, live from Scheme.
  (syscall->procedure int "ioctl" (list int unsigned-long '*)))

(define (bytes->string bytes)
  "Read BYTES, a list of bytes, and return the null-terminated string decoded
from there, or #f if that would be an empty string."
  (match (take-while (negate zero?) bytes)
    (()
     #f)
    (non-zero
     (list->string (map integer->char non-zero)))))

(define (bytevector->string-list bv stride len)
  "Return the null-terminated strings found in BV every STRIDE bytes.  Read at
most LEN bytes from BV."
  (let loop ((bytes  (take (bytevector->u8-list bv)
                           (min len (bytevector-length bv))))
             (result '()))
    (match bytes
      (()
       (reverse result))
      (_
       (loop (drop bytes stride)
             (cons (bytes->string bytes) result))))))

(define* (network-interface-names #:optional sock)
  "Return the names of existing network interfaces.  This is typically limited
to interfaces that are currently up."
  (let* ((close? (not sock))
         (sock   (or sock (socket SOCK_STREAM AF_INET 0)))
         (len    (* ifreq-struct-size 10))
         (reqs   (make-bytevector len))
         (conf   (make-bytevector sizeof-ifconf)))
    (write-ifconf! conf 0
                   len (bytevector->pointer reqs))

    (let-values (((ret err)
                  (%ioctl (fileno sock) SIOCGIFCONF
                          (bytevector->pointer conf))))
      (when close?
        (close-port sock))
      (if (zero? ret)
          (bytevector->string-list reqs ifreq-struct-size
                                   (match (read-ifconf conf)
                                     ((len . _) len)))
          (throw 'system-error "network-interface-list"
                 "network-interface-list: ~A"
                 (list (strerror err))
                 (list err))))))

(define %interface-line
  ;; Regexp matching an interface line in Linux's /proc/net/dev.
  (make-regexp "^[[:blank:]]*([[:graph:]]+):.*$"))

(define (all-network-interface-names)
  "Return all the names of the registered network interfaces, including those
that are not up."
  (call-with-input-file "/proc/net/dev"           ;XXX: Linux-specific
    (lambda (port)
      (let loop ((interfaces '()))
        (let ((line (read-line port)))
          (cond ((eof-object? line)
                 (reverse interfaces))
                ((regexp-exec %interface-line line)
                 =>
                 (lambda (match)
                   (loop (cons (match:substring match 1) interfaces))))
                (else
                 (loop interfaces))))))))

(define-as-needed (network-interface-flags socket name)
  "Return a number that is the bit-wise or of 'IFF*' flags for network
interface NAME."
  (let ((req (make-bytevector ifreq-struct-size)))
    (bytevector-copy! (string->utf8 name) 0 req 0
                      (min (string-length name) (- IF_NAMESIZE 1)))
    (let-values (((ret err)
                  (%ioctl (fileno socket) SIOCGIFFLAGS
                          (bytevector->pointer req))))
      (if (zero? ret)

          ;; The 'ifr_flags' field is IF_NAMESIZE bytes after the
          ;; beginning of 'struct ifreq', and it's a short int.
          (bytevector-sint-ref req IF_NAMESIZE (native-endianness)
                               (sizeof short))

          (throw 'system-error "network-interface-flags"
                 "network-interface-flags on ~A: ~A"
                 (list name (strerror err))
                 (list err))))))

(define (loopback-network-interface? name)
  "Return true if NAME designates a loopback network interface."
  (let* ((sock  (socket SOCK_STREAM AF_INET 0))
         (flags (network-interface-flags sock name)))
    (close-port sock)
    (not (zero? (logand flags IFF_LOOPBACK)))))

(define (network-interface-running? name)
  "Return true if NAME designates a running network interface."
  (let* ((sock  (socket SOCK_STREAM AF_INET 0))
         (flags (network-interface-flags sock name)))
    (close-port sock)
    (not (zero? (logand flags IFF_RUNNING)))))

(define (arp-network-interface? name)
  "Return true if NAME supports the Address Resolution Protocol."
  (let* ((sock  (socket SOCK_STREAM AF_INET 0))
         (flags (network-interface-flags sock name)))
    (close-port sock)
    (zero? (logand flags IFF_NOARP))))

(define-as-needed (set-network-interface-flags socket name flags)
  "Set the flag of network interface NAME to FLAGS."
  (let ((req (make-bytevector ifreq-struct-size)))
    (bytevector-copy! (string->utf8 name) 0 req 0
                      (min (string-length name) (- IF_NAMESIZE 1)))
    ;; Set the 'ifr_flags' field.
    (bytevector-uint-set! req IF_NAMESIZE flags (native-endianness)
                          (sizeof short))
    (let-values (((ret err)
                  (%ioctl (fileno socket) SIOCSIFFLAGS
                          (bytevector->pointer req))))
      (unless (zero? ret)
        (throw 'system-error "set-network-interface-flags"
               "set-network-interface-flags on ~A: ~A"
               (list name (strerror err))
               (list err))))))

(define-as-needed (set-network-interface-address socket name sockaddr)
  "Set the address of network interface NAME to SOCKADDR."
  (let ((req (make-bytevector ifreq-struct-size)))
    (bytevector-copy! (string->utf8 name) 0 req 0
                      (min (string-length name) (- IF_NAMESIZE 1)))
    ;; Set the 'ifr_addr' field.
    (write-socket-address! sockaddr req IF_NAMESIZE)
    (let-values (((ret err)
                  (%ioctl (fileno socket) SIOCSIFADDR
                          (bytevector->pointer req))))
      (unless (zero? ret)
        (throw 'system-error "set-network-interface-address"
               "set-network-interface-address on ~A: ~A"
               (list name (strerror err))
               (list err))))))

(define (set-network-interface-netmask socket name sockaddr)
  "Set the network mask of interface NAME to SOCKADDR."
  (let ((req (make-bytevector ifreq-struct-size)))
    (bytevector-copy! (string->utf8 name) 0 req 0
                      (min (string-length name) (- IF_NAMESIZE 1)))
    ;; Set the 'ifr_addr' field.
    (write-socket-address! sockaddr req IF_NAMESIZE)
    (let-values (((ret err)
                  (%ioctl (fileno socket) SIOCSIFNETMASK
                          (bytevector->pointer req))))
      (unless (zero? ret)
        (throw 'system-error "set-network-interface-netmask"
               "set-network-interface-netmask on ~A: ~A"
               (list name (strerror err))
               (list err))))))

(define (network-interface-address socket name)
  "Return the address of network interface NAME.  The result is an object of
the same type as that returned by 'make-socket-address'."
  (let ((req (make-bytevector ifreq-struct-size)))
    (bytevector-copy! (string->utf8 name) 0 req 0
                      (min (string-length name) (- IF_NAMESIZE 1)))
    (let-values (((ret err)
                  (%ioctl (fileno socket) SIOCGIFADDR
                          (bytevector->pointer req))))
      (if (zero? ret)
          (read-socket-address req IF_NAMESIZE)
          (throw 'system-error "network-interface-address"
                 "network-interface-address on ~A: ~A"
                 (list name (strerror err))
                 (list err))))))

(define (network-interface-netmask socket name)
  "Return the netmask of network interface NAME.  The result is an object of
the same type as that returned by 'make-socket-address'."
  (let ((req (make-bytevector ifreq-struct-size)))
    (bytevector-copy! (string->utf8 name) 0 req 0
                      (min (string-length name) (- IF_NAMESIZE 1)))
    (let-values (((ret err)
                  (%ioctl (fileno socket) SIOCGIFNETMASK
                          (bytevector->pointer req))))
      (if (zero? ret)
          (read-socket-address req IF_NAMESIZE)
          (throw 'system-error "network-interface-netmask"
                 "network-interface-netmask on ~A: ~A"
                 (list name (strerror err))
                 (list err))))))

(define* (configure-network-interface name sockaddr flags
                                      #:key netmask)
  "Configure network interface NAME to use SOCKADDR, an address as returned by
'make-socket-address', and FLAGS, a bitwise-or of IFF_* constants.  If NETMASK
is true, it must be a socket address to use as the network mask."
  (let ((sock (socket (sockaddr:fam sockaddr) SOCK_STREAM 0)))
    (dynamic-wind
      (const #t)
      (lambda ()
        (set-network-interface-address sock name sockaddr)
        (set-network-interface-flags sock name flags)
        (when netmask
          (set-network-interface-netmask sock name netmask)))
      (lambda ()
        (close-port sock)))))

(define* (set-network-interface-up name
                                   #:key (family AF_INET))
  "Turn up the interface NAME."
  (let ((sock (socket family SOCK_STREAM 0)))
    (dynamic-wind
      (const #t)
      (lambda ()
        (let ((flags (network-interface-flags sock name)))
          (set-network-interface-flags sock name
                                       (logior flags IFF_UP))))
      (lambda ()
        (close-port sock)))))

\f
;;;
;;; Network routes.
;;;

(define-c-struct %rtentry                 ;'struct rtentry' from <net/route.h>
  sizeof-rtentry
  list
  read-rtentry
  write-rtentry!
  (pad1            unsigned-long)
  (destination     (array uint8 16))              ;struct sockaddr
  (gateway         (array uint8 16))              ;struct sockaddr
  (genmask         (array uint8 16))              ;struct sockaddr
  (flags           unsigned-short)
  (pad2            short)
  (pad3            long)
  (tos             uint8)
  (class           uint8)
  (pad4            (array uint8 (if (= 8 (sizeof* '*)) 3 1)))
  (metric          short)
  (device          '*)
  (mtu             unsigned-long)
  (window          unsigned-long)
  (initial-rtt     unsigned-short))

(define RTF_UP #x0001)                     ;'rtentry' flags from <net/route.h>
(define RTF_GATEWAY #x0002)

(define %sockaddr-any
  (make-socket-address AF_INET INADDR_ANY 0))

(define add-network-route/gateway
  ;; To allow field names to be matched as literals, we need to move them out
  ;; of the lambda's body since the parameters have the same name.  A lot of
  ;; fuss for very little.
  (let-syntax ((gateway-offset (identifier-syntax
                                (c-struct-field-offset %rtentry gateway)))
               (destination-offset (identifier-syntax
                                    (c-struct-field-offset %rtentry destination)))
               (genmask-offset (identifier-syntax
                                (c-struct-field-offset %rtentry genmask))))
    (lambda* (socket gateway
                     #:key (destination %sockaddr-any) (genmask %sockaddr-any))
      "Add a network route for DESTINATION (a socket address as returned by
'make-socket-address') that goes through GATEWAY (a socket address).  For
instance, the call:

  (add-network-route/gateway sock
                             (make-socket-address
                               AF_INET
                               (inet-pton AF_INET \"192.168.0.1\")
                               0))

is equivalent to this 'net-tools' command:

  route add -net default gw 192.168.0.1

because the default value of DESTINATION is \"0.0.0.0\"."
      (let ((route (make-bytevector sizeof-rtentry 0)))
        (write-socket-address! gateway route gateway-offset)
        (write-socket-address! destination route destination-offset)
        (write-socket-address! genmask route genmask-offset)
        (bytevector-u16-native-set! route
                                    (c-struct-field-offset %rtentry flags)
                                    (logior RTF_UP RTF_GATEWAY))
        (let-values (((ret err)
                      (%ioctl (fileno socket) SIOCADDRT
                              (bytevector->pointer route))))
          (unless (zero? ret)
            (throw 'system-error "add-network-route/gateway"
                   "add-network-route/gateway: ~A"
                   (list (strerror err))
                   (list err))))))))

(define delete-network-route
  (let-syntax ((destination-offset (identifier-syntax
                                    (c-struct-field-offset %rtentry destination))))
    (lambda* (socket destination)
      "Delete the network route for DESTINATION.  For instance, the call:

  (delete-network-route sock
                        (make-socket-address AF_INET INADDR_ANY 0))

is equivalent to the 'net-tools' command:

  route del -net default
"

      (let ((route (make-bytevector sizeof-rtentry 0)))
        (write-socket-address! destination route destination-offset)
        (let-values (((ret err)
                      (%ioctl (fileno socket) SIOCDELRT
                              (bytevector->pointer route))))
          (unless (zero? ret)
            (throw 'system-error "delete-network-route"
                   "delete-network-route: ~A"
                   (list (strerror err))
                   (list err))))))))

\f
;;;
;;; Details about network interfaces---aka. 'getifaddrs'.
;;;

;; Network interfaces.  XXX: We would call it <network-interface> but that
;; would collide with the ioctl wrappers above.
(define-record-type <interface>
  (make-interface name flags address netmask broadcast-address)
  interface?
  (name              interface-name)               ;string
  (flags             interface-flags)              ;or'd IFF_* values
  (address           interface-address)            ;sockaddr | #f
  (netmask           interface-netmask)            ;sockaddr | #f
  (broadcast-address interface-broadcast-address)) ;sockaddr | #f

(define (write-interface interface port)
  (match interface
    (($ <interface> name flags address)
     (format port "#<interface ~s " name)
     (unless (zero? (logand IFF_UP flags))
       (display "up " port))

     ;; Check whether ADDRESS really is a sockaddr.
     (when address
       (if (member (sockaddr:fam address) (list AF_INET AF_INET6))
           (format port "~a " (inet-ntop (sockaddr:fam address)
                                         (sockaddr:addr address)))
           (format port "family:~a " (sockaddr:fam address))))

     (format port "~a>" (number->string (object-address interface) 16)))))

(set-record-type-printer! <interface> write-interface)

(define (values->interface next name flags address netmask
                           broadcast-address data)
  "Given the raw field values passed as arguments, return a pair whose car is
an <interface> object, and whose cdr is the pointer NEXT."
  (define (maybe-socket-address pointer)
    (if (null-pointer? pointer)
        #f
        (read-socket-address (pointer->bytevector pointer 50)))) ;XXX: size

  (cons (make-interface (if (null-pointer? name)
                            #f
                            (pointer->string name))
                        flags
                        (maybe-socket-address address)
                        (maybe-socket-address netmask)
                        (maybe-socket-address broadcast-address)
                        ;; Ignore DATA.
                        )
        next))

(define-c-struct ifaddrs                          ;<ifaddrs.h>
  %sizeof-ifaddrs
  values->interface
  read-ifaddrs
  write-ifaddrs!
  (next          '*)
  (name          '*)
  (flags         unsigned-int)
  (addr          '*)
  (netmask       '*)
  (broadcastaddr '*)
  (data          '*))

(define (unfold-interface-list ptr)
  "Call 'read-ifaddrs' on PTR and all its 'next' fields, recursively, and
return the list of resulting <interface> objects."
  (let loop ((ptr    ptr)
             (result '()))
    (if (null-pointer? ptr)
        (reverse result)
        (match (read-ifaddrs (pointer->bytevector ptr %sizeof-ifaddrs))
          ((ifaddr . ptr)
           (loop ptr (cons ifaddr result)))))))

(define network-interfaces
  (let ((proc (syscall->procedure int "getifaddrs" (list '*))))
    (lambda ()
      "Return a list of <interface> objects, each denoting a configured
network interface.  This is implemented using the 'getifaddrs' libc function."
      (let*-values (((ptr)
                     (bytevector->pointer (make-bytevector (sizeof* '*))))
                    ((ret err)
                     (proc ptr)))
        (if (zero? ret)
            (let* ((ptr    (dereference-pointer ptr))
                   (result (unfold-interface-list ptr)))
              (free-ifaddrs ptr)
              result)
            (throw 'system-error "network-interfaces" "~A"
                   (list (strerror err))
                   (list err)))))))

(define free-ifaddrs
  (syscall->procedure void "freeifaddrs" '(*)))

\f
;;;
;;; Terminals.
;;;

(define-syntax bits->symbols-body
  (syntax-rules ()
    ((_ bits () ())
     '())
    ((_ bits (name names ...) (value values ...))
     (let ((result (bits->symbols-body bits (names ...) (values ...))))
       (if (zero? (logand bits value))
           result
           (cons 'name result))))))

(define-syntax define-bits
  (syntax-rules (define)
    "Define the given numerical constants under CONSTRUCTOR, such that
 (CONSTRUCTOR NAME) returns VALUE.  Define BITS->SYMBOLS as a procedure that,
given an integer, returns the list of names of the constants that are or'd."
    ((_ constructor bits->symbols (define names values) ...)
     (begin
       (define-syntax constructor
         (syntax-rules (names ...)
           ((_) 0)
           ((_ names) values) ...
           ((_ first rest (... ...))
            (logior (constructor first) rest (... ...)))))
       (define (bits->symbols bits)
         (bits->symbols-body bits (names ...) (values ...)))))))

;; 'local-flags' bits from <bits/termios.h>
(define-bits local-flags
  local-flags->symbols
 (define ISIG #o0000001)
 (define ICANON #o0000002)
 (define XCASE #o0000004)
 (define ECHO #o0000010)
 (define ECHOE #o0000020)
 (define ECHOK #o0000040)
 (define ECHONL #o0000100)
 (define NOFLSH #o0000200)
 (define TOSTOP #o0000400)
 (define ECHOCTL #o0001000)
 (define ECHOPRT #o0002000)
 (define ECHOKE #o0004000)
 (define FLUSHO #o0010000)
 (define PENDIN #o0040000)
 (define IEXTEN #o0100000)
 (define EXTPROC #o0200000))

(define-bits input-flags
  input-flags->symbols
  (define IGNBRK #o0000001)
  (define BRKINT #o0000002)
  (define IGNPAR #o0000004)
  (define PARMRK #o0000010)
  (define INPCK #o0000020)
  (define ISTRIP #o0000040)
  (define INLCR #o0000100)
  (define IGNCR #o0000200)
  (define ICRNL #o0000400)
  (define IUCLC #o0001000)
  (define IXON #o0002000)
  (define IXANY #o0004000)
  (define IXOFF #o0010000)
  (define IMAXBEL #o0020000)
  (define IUTF8 #o0040000))

;; "Actions" values for 'tcsetattr'.
(define-bits tcsetattr-action
  %unused-tcsetattr-action->symbols
  (define TCSANOW  0)
  (define TCSADRAIN 1)
  (define TCSAFLUSH 2))

(define-record-type <termios>
  (termios input-flags output-flags control-flags local-flags
           line-discipline control-chars
           input-speed output-speed)
  termios?
  (input-flags      termios-input-flags)
  (output-flags     termios-output-flags)
  (control-flags    termios-control-flags)
  (local-flags      termios-local-flags)
  (line-discipline  termios-line-discipline)
  (control-chars    termios-control-chars)
  (input-speed      termios-input-speed)
  (output-speed     termios-output-speed))

(define-c-struct %termios                         ;<bits/termios.h>
  sizeof-termios
  termios
  read-termios
  write-termios!
  (input-flags      unsigned-int)
  (output-flags     unsigned-int)
  (control-flags    unsigned-int)
  (local-flags      unsigned-int)
  (line-discipline  uint8)
  (control-chars    (array uint8 32))
  (input-speed      unsigned-int)
  (output-speed     unsigned-int))

(define tcgetattr
  (let ((proc (syscall->procedure int "tcgetattr" (list int '*))))
    (lambda (fd)
      "Return the <termios> structure for the tty at FD."
      (let*-values (((bv)      (make-bytevector sizeof-termios))
                    ((ret err) (proc fd (bytevector->pointer bv))))
        (if (zero? ret)
            (read-termios bv)
            (throw 'system-error "tcgetattr" "~A"
                   (list (strerror err))
                   (list err)))))))

(define tcsetattr
  (let ((proc (syscall->procedure int "tcsetattr" (list int int '*))))
    (lambda (fd actions termios)
      "Use TERMIOS for the tty at FD.  ACTIONS is one of of the values
produced by 'tcsetattr-action'; see tcsetattr(3) for details."
      (define bv
        (make-bytevector sizeof-termios))

      (let-syntax ((match/write (syntax-rules ()
                                  ((_ fields ...)
                                   (match termios
                                     (($ <termios> fields ...)
                                      (write-termios! bv 0 fields ...)))))))
        (match/write input-flags output-flags control-flags local-flags
                     line-discipline control-chars input-speed output-speed))

      (let-values (((ret err) (proc fd actions (bytevector->pointer bv))))
        (unless (zero? ret)
          (throw 'system-error "tcgetattr" "~A"
                 (list (strerror err))
                 (list err)))))))

(define-syntax TIOCGWINSZ                         ;<asm-generic/ioctls.h>
  (identifier-syntax #x5413))

(define-record-type <window-size>
  (window-size rows columns x-pixels y-pixels)
  window-size?
  (rows     window-size-rows)
  (columns  window-size-columns)
  (x-pixels window-size-x-pixels)
  (y-pixels window-size-y-pixels))

(define-c-struct winsize                          ;<bits/ioctl-types.h>
  sizeof-winsize
  window-size
  read-winsize
  write-winsize!
  (rows          unsigned-short)
  (columns       unsigned-short)
  (x-pixels      unsigned-short)
  (y-pixels      unsigned-short))

(define* (terminal-window-size #:optional (port (current-output-port)))
  "Return a <window-size> structure describing the terminal at PORT, or raise
a 'system-error' if PORT is not backed by a terminal.  This procedure
corresponds to the TIOCGWINSZ ioctl."
  (let*-values (((size)    (make-bytevector sizeof-winsize))
                ((ret err) (%ioctl (fileno port) TIOCGWINSZ
                                   (bytevector->pointer size))))
    (if (zero? ret)
        (read-winsize size)
        (throw 'system-error "terminal-window-size" "~A"
               (list (strerror err))
               (list err)))))

(define (terminal-dimension window-dimension port fall-back)
  "Return the terminal dimension defined by WINDOW-DIMENSION, one of
'window-size-columns' or 'window-size-rows' for PORT.  If PORT does not
correspond to a terminal, return the value returned by FALL-BACK."
  (catch 'system-error
    (lambda ()
      (if (file-port? port)
          (match (window-dimension (terminal-window-size port))
            ;; Things like Emacs shell-mode return 0, which is unreasonable.
            (0 (fall-back))
            ((? number? n) n))
          (fall-back)))
    (lambda args
      (let ((errno (system-error-errno args)))
        ;; ENOTTY is what we're after but 2012-and-earlier Linux versions
        ;; would return EINVAL instead in some cases:
        ;; <https://bugs.ruby-lang.org/issues/10494>.
        ;; Furthermore, some FUSE file systems like unionfs return ENOSYS for
        ;; that ioctl.
        (if (memv errno (list ENOTTY EINVAL ENOSYS))
            (fall-back)
            (apply throw args))))))

(define* (terminal-columns #:optional (port (current-output-port)))
  "Return the best approximation of the number of columns of the terminal at
PORT, trying to guess a reasonable value if all else fails.  The result is
always a positive integer."
  (define (fall-back)
    (match (and=> (getenv "COLUMNS") string->number)
      (#f 80)
      ((? number? columns)
       (if (> columns 0) columns 80))))

  (terminal-dimension window-size-columns port fall-back))

(define* (terminal-rows #:optional (port (current-output-port)))
  "Return the best approximation of the number of rows of the terminal at
PORT, trying to guess a reasonable value if all else fails.  The result is
always a positive integer."
  (terminal-dimension window-size-rows port (const 25)))

\f
;;;
;;; utmpx.
;;;

(define-record-type <utmpx-entry>
  (utmpx type pid line id user host termination exit
         session time address)
  utmpx?
  (type           utmpx-login-type)               ;login-type
  (pid            utmpx-pid)
  (line           utmpx-line)                     ;device name
  (id             utmpx-id)
  (user           utmpx-user)                     ;user name
  (host           utmpx-host)                     ;host name | #f
  (termination    utmpx-termination-status)
  (exit           utmpx-exit-status)
  (session        utmpx-session-id)               ;session ID, for windowing
  (time           utmpx-time)                     ;entry time
  (address        utmpx-address))

(define-c-struct %utmpx                           ;<utmpx.h>
  sizeof-utmpx
  (lambda (type pid line id user host termination exit session
                seconds useconds address %reserved)
    (utmpx type pid
           (bytes->string line) id
           (bytes->string user)
           (bytes->string host) termination exit
           session
           (make-time time-utc (* 1000 useconds) seconds)
           address))
  read-utmpx
  write-utmpx!
  (type           short)
  (pid            int)
  (line           (array uint8 32))
  (id             (array uint8 4))
  (user           (array uint8 32))
  (host           (array uint8 256))
  (termination    short)
  (exit           short)
  (session        int32)
  (time-seconds   int32)
  (time-useconds  int32)
  (address-v6     (array int32 4))
  (%reserved      (array uint8 20)))

(define-bits login-type
  %unused-login-type->symbols
  (define EMPTY 0)                      ;No valid user accounting information.
  (define RUN_LVL 1)                    ;The system's runlevel.
  (define BOOT_TIME 2)                  ;Time of system boot.
  (define NEW_TIME 3)                   ;Time after system clock changed.
  (define OLD_TIME 4)                   ;Time when system clock changed.

  (define INIT_PROCESS 5)                ;Process spawned by the init process.
  (define LOGIN_PROCESS 6)               ;Session leader of a logged in user.
  (define USER_PROCESS 7)                ;Normal process.
  (define DEAD_PROCESS 8)                ;Terminated process.

  (define ACCOUNTING 9))                 ;System accounting.

(define setutxent
  (let ((proc (syscall->procedure void "setutxent" '())))
    (lambda ()
      "Open the user accounting database."
      (proc))))

(define endutxent
  (let ((proc (syscall->procedure void "endutxent" '())))
    (lambda ()
      "Close the user accounting database."
      (proc))))

(define getutxent
  (let ((proc (syscall->procedure '* "getutxent" '())))
    (lambda ()
      "Return the next entry from the user accounting database."
      (let ((ptr (proc)))
        (if (null-pointer? ptr)
            #f
            (read-utmpx (pointer->bytevector ptr sizeof-utmpx)))))))

(define (utmpx-entries)
  "Return the list of entries read from the user accounting database."
  (setutxent)
  (let loop ((entries '()))
    (match (getutxent)
      (#f
       (endutxent)
       (reverse entries))
      ((? utmpx? entry)
       (loop (cons entry entries))))))

(define (read-utmpx-from-port port)
  "Read a utmpx entry from PORT.  Return either the EOF object or a utmpx
entry."
  (match (get-bytevector-n port sizeof-utmpx)
    ((? eof-object? eof)
     eof)
    ((? bytevector? bv)
     (read-utmpx bv))))

;;; syscalls.scm ends here

debug log:

solving 99a3b45004 ...
found 99a3b45004 in https://git.savannah.gnu.org/cgit/guix.git

(*) Git path names are given by the tree(s) the blob belongs to.
    Blobs themselves have no identifier aside from the hash of its contents.^

Code repositories for project(s) associated with this external index

	https://git.savannah.gnu.org/cgit/guix.git

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.