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
|
/* $OpenBSD: kern_sig.c,v 1.248 2020/02/19 11:33:48 claudio Exp $ */
/* $NetBSD: kern_sig.c,v 1.54 1996/04/22 01:38:32 christos Exp $ */
/*
* Copyright (c) 1997 Theo de Raadt. All rights reserved.
* Copyright (c) 1982, 1986, 1989, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kern_sig.c 8.7 (Berkeley) 4/18/94
*/
#define SIGPROP /* include signal properties table */
#include <sys/param.h>
#include <sys/signalvar.h>
#include <sys/resourcevar.h>
#include <sys/queue.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/event.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/acct.h>
#include <sys/fcntl.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/wait.h>
#include <sys/ktrace.h>
#include <sys/stat.h>
#include <sys/core.h>
#include <sys/malloc.h>
#include <sys/pool.h>
#include <sys/ptrace.h>
#include <sys/sched.h>
#include <sys/user.h>
#include <sys/syslog.h>
#include <sys/ttycom.h>
#include <sys/pledge.h>
#include <sys/witness.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
#include <uvm/uvm_extern.h>
#include <machine/tcb.h>
int filt_sigattach(struct knote *kn);
void filt_sigdetach(struct knote *kn);
int filt_signal(struct knote *kn, long hint);
const struct filterops sig_filtops = {
.f_isfd = 0,
.f_attach = filt_sigattach,
.f_detach = filt_sigdetach,
.f_event = filt_signal,
};
void proc_stop(struct proc *p, int);
void proc_stop_sweep(void *);
void *proc_stop_si;
void postsig(struct proc *, int);
int cansignal(struct proc *, struct process *, int);
struct pool sigacts_pool; /* memory pool for sigacts structures */
void sigio_del(struct sigiolst *);
void sigio_unlink(struct sigio_ref *, struct sigiolst *);
struct mutex sigio_lock = MUTEX_INITIALIZER(IPL_HIGH);
/*
* Can thread p, send the signal signum to process qr?
*/
int
cansignal(struct proc *p, struct process *qr, int signum)
{
struct process *pr = p->p_p;
struct ucred *uc = p->p_ucred;
struct ucred *quc = qr->ps_ucred;
if (uc->cr_uid == 0)
return (1); /* root can always signal */
if (pr == qr)
return (1); /* process can always signal itself */
/* optimization: if the same creds then the tests below will pass */
if (uc == quc)
return (1);
if (signum == SIGCONT && qr->ps_session == pr->ps_session)
return (1); /* SIGCONT in session */
/*
* Using kill(), only certain signals can be sent to setugid
* child processes
*/
if (qr->ps_flags & PS_SUGID) {
switch (signum) {
case 0:
case SIGKILL:
case SIGINT:
case SIGTERM:
case SIGALRM:
case SIGSTOP:
case SIGTTIN:
case SIGTTOU:
case SIGTSTP:
case SIGHUP:
case SIGUSR1:
case SIGUSR2:
if (uc->cr_ruid == quc->cr_ruid ||
uc->cr_uid == quc->cr_ruid)
return (1);
}
return (0);
}
if (uc->cr_ruid == quc->cr_ruid ||
uc->cr_ruid == quc->cr_svuid ||
uc->cr_uid == quc->cr_ruid ||
uc->cr_uid == quc->cr_svuid)
return (1);
return (0);
}
/*
* Initialize signal-related data structures.
*/
void
signal_init(void)
{
proc_stop_si = softintr_establish(IPL_SOFTCLOCK, proc_stop_sweep,
NULL);
if (proc_stop_si == NULL)
panic("signal_init failed to register softintr");
pool_init(&sigacts_pool, sizeof(struct sigacts), 0, IPL_NONE,
PR_WAITOK, "sigapl", NULL);
}
/*
* Create an initial sigacts structure, using the same signal state
* as p.
*/
struct sigacts *
sigactsinit(struct process *pr)
{
struct sigacts *ps;
ps = pool_get(&sigacts_pool, PR_WAITOK);
memcpy(ps, pr->ps_sigacts, sizeof(struct sigacts));
ps->ps_refcnt = 1;
return (ps);
}
/*
* Share a sigacts structure.
*/
struct sigacts *
sigactsshare(struct process *pr)
{
struct sigacts *ps = pr->ps_sigacts;
ps->ps_refcnt++;
return ps;
}
/*
* Initialize a new sigaltstack structure.
*/
void
sigstkinit(struct sigaltstack *ss)
{
ss->ss_flags = SS_DISABLE;
ss->ss_size = 0;
ss->ss_sp = 0;
}
/*
* Make this process not share its sigacts, maintaining all
* signal state.
*/
void
sigactsunshare(struct process *pr)
{
struct sigacts *newps;
if (pr->ps_sigacts->ps_refcnt == 1)
return;
newps = sigactsinit(pr);
sigactsfree(pr);
pr->ps_sigacts = newps;
}
/*
* Release a sigacts structure.
*/
void
sigactsfree(struct process *pr)
{
struct sigacts *ps = pr->ps_sigacts;
if (--ps->ps_refcnt > 0)
return;
pr->ps_sigacts = NULL;
pool_put(&sigacts_pool, ps);
}
int
sys_sigaction(struct proc *p, void *v, register_t *retval)
{
struct sys_sigaction_args /* {
syscallarg(int) signum;
syscallarg(const struct sigaction *) nsa;
syscallarg(struct sigaction *) osa;
} */ *uap = v;
struct sigaction vec;
#ifdef KTRACE
struct sigaction ovec;
#endif
struct sigaction *sa;
const struct sigaction *nsa;
struct sigaction *osa;
struct sigacts *ps = p->p_p->ps_sigacts;
int signum;
int bit, error;
signum = SCARG(uap, signum);
nsa = SCARG(uap, nsa);
osa = SCARG(uap, osa);
if (signum <= 0 || signum >= NSIG ||
(nsa && (signum == SIGKILL || signum == SIGSTOP)))
return (EINVAL);
sa = &vec;
if (osa) {
sa->sa_handler = ps->ps_sigact[signum];
sa->sa_mask = ps->ps_catchmask[signum];
bit = sigmask(signum);
sa->sa_flags = 0;
if ((ps->ps_sigonstack & bit) != 0)
sa->sa_flags |= SA_ONSTACK;
if ((ps->ps_sigintr & bit) == 0)
sa->sa_flags |= SA_RESTART;
if ((ps->ps_sigreset & bit) != 0)
sa->sa_flags |= SA_RESETHAND;
if ((ps->ps_siginfo & bit) != 0)
sa->sa_flags |= SA_SIGINFO;
if (signum == SIGCHLD) {
if ((ps->ps_flags & SAS_NOCLDSTOP) != 0)
sa->sa_flags |= SA_NOCLDSTOP;
if ((ps->ps_flags & SAS_NOCLDWAIT) != 0)
sa->sa_flags |= SA_NOCLDWAIT;
}
if ((sa->sa_mask & bit) == 0)
sa->sa_flags |= SA_NODEFER;
sa->sa_mask &= ~bit;
error = copyout(sa, osa, sizeof (vec));
if (error)
return (error);
#ifdef KTRACE
if (KTRPOINT(p, KTR_STRUCT))
ovec = vec;
#endif
}
if (nsa) {
error = copyin(nsa, sa, sizeof (vec));
if (error)
return (error);
#ifdef KTRACE
if (KTRPOINT(p, KTR_STRUCT))
ktrsigaction(p, sa);
#endif
setsigvec(p, signum, sa);
}
#ifdef KTRACE
if (osa && KTRPOINT(p, KTR_STRUCT))
ktrsigaction(p, &ovec);
#endif
return (0);
}
void
setsigvec(struct proc *p, int signum, struct sigaction *sa)
{
struct sigacts *ps = p->p_p->ps_sigacts;
int bit;
int s;
bit = sigmask(signum);
/*
* Change setting atomically.
*/
s = splhigh();
ps->ps_sigact[signum] = sa->sa_handler;
if ((sa->sa_flags & SA_NODEFER) == 0)
sa->sa_mask |= sigmask(signum);
ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask;
if (signum == SIGCHLD) {
if (sa->sa_flags & SA_NOCLDSTOP)
atomic_setbits_int(&ps->ps_flags, SAS_NOCLDSTOP);
else
atomic_clearbits_int(&ps->ps_flags, SAS_NOCLDSTOP);
/*
* If the SA_NOCLDWAIT flag is set or the handler
* is SIG_IGN we reparent the dying child to PID 1
* (init) which will reap the zombie. Because we use
* init to do our dirty work we never set SAS_NOCLDWAIT
* for PID 1.
* XXX exit1 rework means this is unnecessary?
*/
if (initprocess->ps_sigacts != ps &&
((sa->sa_flags & SA_NOCLDWAIT) ||
sa->sa_handler == SIG_IGN))
atomic_setbits_int(&ps->ps_flags, SAS_NOCLDWAIT);
else
atomic_clearbits_int(&ps->ps_flags, SAS_NOCLDWAIT);
}
if ((sa->sa_flags & SA_RESETHAND) != 0)
ps->ps_sigreset |= bit;
else
ps->ps_sigreset &= ~bit;
if ((sa->sa_flags & SA_SIGINFO) != 0)
ps->ps_siginfo |= bit;
else
ps->ps_siginfo &= ~bit;
if ((sa->sa_flags & SA_RESTART) == 0)
ps->ps_sigintr |= bit;
else
ps->ps_sigintr &= ~bit;
if ((sa->sa_flags & SA_ONSTACK) != 0)
ps->ps_sigonstack |= bit;
else
ps->ps_sigonstack &= ~bit;
/*
* Set bit in ps_sigignore for signals that are set to SIG_IGN,
* and for signals set to SIG_DFL where the default is to ignore.
* However, don't put SIGCONT in ps_sigignore,
* as we have to restart the process.
*/
if (sa->sa_handler == SIG_IGN ||
(sigprop[signum] & SA_IGNORE && sa->sa_handler == SIG_DFL)) {
atomic_clearbits_int(&p->p_siglist, bit);
atomic_clearbits_int(&p->p_p->ps_siglist, bit);
if (signum != SIGCONT)
ps->ps_sigignore |= bit; /* easier in psignal */
ps->ps_sigcatch &= ~bit;
} else {
ps->ps_sigignore &= ~bit;
if (sa->sa_handler == SIG_DFL)
ps->ps_sigcatch &= ~bit;
else
ps->ps_sigcatch |= bit;
}
splx(s);
}
/*
* Initialize signal state for process 0;
* set to ignore signals that are ignored by default.
*/
void
siginit(struct process *pr)
{
struct sigacts *ps = pr->ps_sigacts;
int i;
for (i = 0; i < NSIG; i++)
if (sigprop[i] & SA_IGNORE && i != SIGCONT)
ps->ps_sigignore |= sigmask(i);
ps->ps_flags = SAS_NOCLDWAIT | SAS_NOCLDSTOP;
}
/*
* Reset signals for an exec by the specified thread.
*/
void
execsigs(struct proc *p)
{
struct sigacts *ps;
int nc, mask;
sigactsunshare(p->p_p);
ps = p->p_p->ps_sigacts;
/*
* Reset caught signals. Held signals remain held
* through p_sigmask (unless they were caught,
* and are now ignored by default).
*/
while (ps->ps_sigcatch) {
nc = ffs((long)ps->ps_sigcatch);
mask = sigmask(nc);
ps->ps_sigcatch &= ~mask;
if (sigprop[nc] & SA_IGNORE) {
if (nc != SIGCONT)
ps->ps_sigignore |= mask;
atomic_clearbits_int(&p->p_siglist, mask);
atomic_clearbits_int(&p->p_p->ps_siglist, mask);
}
ps->ps_sigact[nc] = SIG_DFL;
}
/*
* Reset stack state to the user stack.
* Clear set of signals caught on the signal stack.
*/
sigstkinit(&p->p_sigstk);
atomic_clearbits_int(&ps->ps_flags, SAS_NOCLDWAIT);
if (ps->ps_sigact[SIGCHLD] == SIG_IGN)
ps->ps_sigact[SIGCHLD] = SIG_DFL;
}
/*
* Manipulate signal mask.
* Note that we receive new mask, not pointer,
* and return old mask as return value;
* the library stub does the rest.
*/
int
sys_sigprocmask(struct proc *p, void *v, register_t *retval)
{
struct sys_sigprocmask_args /* {
syscallarg(int) how;
syscallarg(sigset_t) mask;
} */ *uap = v;
int error = 0;
sigset_t mask;
*retval = p->p_sigmask;
mask = SCARG(uap, mask) &~ sigcantmask;
switch (SCARG(uap, how)) {
case SIG_BLOCK:
atomic_setbits_int(&p->p_sigmask, mask);
break;
case SIG_UNBLOCK:
atomic_clearbits_int(&p->p_sigmask, mask);
break;
case SIG_SETMASK:
p->p_sigmask = mask;
break;
default:
error = EINVAL;
break;
}
return (error);
}
int
sys_sigpending(struct proc *p, void *v, register_t *retval)
{
*retval = p->p_siglist | p->p_p->ps_siglist;
return (0);
}
/*
* Temporarily replace calling proc's signal mask for the duration of a
* system call. Original signal mask will be restored by userret().
*/
void
dosigsuspend(struct proc *p, sigset_t newmask)
{
KASSERT(p == curproc);
p->p_oldmask = p->p_sigmask;
atomic_setbits_int(&p->p_flag, P_SIGSUSPEND);
p->p_sigmask = newmask;
}
/*
* Suspend process until signal, providing mask to be set
* in the meantime. Note nonstandard calling convention:
* libc stub passes mask, not pointer, to save a copyin.
*/
int
sys_sigsuspend(struct proc *p, void *v, register_t *retval)
{
struct sys_sigsuspend_args /* {
syscallarg(int) mask;
} */ *uap = v;
struct process *pr = p->p_p;
struct sigacts *ps = pr->ps_sigacts;
dosigsuspend(p, SCARG(uap, mask) &~ sigcantmask);
while (tsleep_nsec(ps, PPAUSE|PCATCH, "pause", INFSLP) == 0)
/* void */;
/* always return EINTR rather than ERESTART... */
return (EINTR);
}
int
sigonstack(size_t stack)
{
const struct sigaltstack *ss = &curproc->p_sigstk;
return (ss->ss_flags & SS_DISABLE ? 0 :
(stack - (size_t)ss->ss_sp < ss->ss_size));
}
int
sys_sigaltstack(struct proc *p, void *v, register_t *retval)
{
struct sys_sigaltstack_args /* {
syscallarg(const struct sigaltstack *) nss;
syscallarg(struct sigaltstack *) oss;
} */ *uap = v;
struct sigaltstack ss;
const struct sigaltstack *nss;
struct sigaltstack *oss;
int onstack = sigonstack(PROC_STACK(p));
int error;
nss = SCARG(uap, nss);
oss = SCARG(uap, oss);
if (oss != NULL) {
ss = p->p_sigstk;
if (onstack)
ss.ss_flags |= SS_ONSTACK;
if ((error = copyout(&ss, oss, sizeof(ss))))
return (error);
}
if (nss == NULL)
return (0);
error = copyin(nss, &ss, sizeof(ss));
if (error)
return (error);
if (onstack)
return (EPERM);
if (ss.ss_flags & ~SS_DISABLE)
return (EINVAL);
if (ss.ss_flags & SS_DISABLE) {
p->p_sigstk.ss_flags = ss.ss_flags;
return (0);
}
if (ss.ss_size < MINSIGSTKSZ)
return (ENOMEM);
error = uvm_map_remap_as_stack(p, (vaddr_t)ss.ss_sp, ss.ss_size);
if (error)
return (error);
p->p_sigstk = ss;
return (0);
}
int
sys_kill(struct proc *cp, void *v, register_t *retval)
{
struct sys_kill_args /* {
syscallarg(int) pid;
syscallarg(int) signum;
} */ *uap = v;
struct process *pr;
int pid = SCARG(uap, pid);
int signum = SCARG(uap, signum);
int error;
int zombie = 0;
if ((error = pledge_kill(cp, pid)) != 0)
return (error);
if (((u_int)signum) >= NSIG)
return (EINVAL);
if (pid > 0) {
if ((pr = prfind(pid)) == NULL) {
if ((pr = zombiefind(pid)) == NULL)
return (ESRCH);
else
zombie = 1;
}
if (!cansignal(cp, pr, signum))
return (EPERM);
/* kill single process */
if (signum && !zombie)
prsignal(pr, signum);
return (0);
}
switch (pid) {
case -1: /* broadcast signal */
return (killpg1(cp, signum, 0, 1));
case 0: /* signal own process group */
return (killpg1(cp, signum, 0, 0));
default: /* negative explicit process group */
return (killpg1(cp, signum, -pid, 0));
}
}
int
sys_thrkill(struct proc *cp, void *v, register_t *retval)
{
struct sys_thrkill_args /* {
syscallarg(pid_t) tid;
syscallarg(int) signum;
syscallarg(void *) tcb;
} */ *uap = v;
struct proc *p;
int tid = SCARG(uap, tid);
int signum = SCARG(uap, signum);
void *tcb;
if (((u_int)signum) >= NSIG)
return (EINVAL);
if (tid > THREAD_PID_OFFSET) {
if ((p = tfind(tid - THREAD_PID_OFFSET)) == NULL)
return (ESRCH);
/* can only kill threads in the same process */
if (p->p_p != cp->p_p)
return (ESRCH);
} else if (tid == 0)
p = cp;
else
return (EINVAL);
/* optionally require the target thread to have the given tcb addr */
tcb = SCARG(uap, tcb);
if (tcb != NULL && tcb != TCB_GET(p))
return (ESRCH);
if (signum)
ptsignal(p, signum, STHREAD);
return (0);
}
/*
* Common code for kill process group/broadcast kill.
* cp is calling process.
*/
int
killpg1(struct proc *cp, int signum, int pgid, int all)
{
struct process *pr;
struct pgrp *pgrp;
int nfound = 0;
if (all) {
/*
* broadcast
*/
LIST_FOREACH(pr, &allprocess, ps_list) {
if (pr->ps_pid <= 1 ||
pr->ps_flags & (PS_SYSTEM | PS_NOBROADCASTKILL) ||
pr == cp->p_p || !cansignal(cp, pr, signum))
continue;
nfound++;
if (signum)
prsignal(pr, signum);
}
} else {
if (pgid == 0)
/*
* zero pgid means send to my process group.
*/
pgrp = cp->p_p->ps_pgrp;
else {
pgrp = pgfind(pgid);
if (pgrp == NULL)
return (ESRCH);
}
LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) {
if (pr->ps_pid <= 1 || pr->ps_flags & PS_SYSTEM ||
!cansignal(cp, pr, signum))
continue;
nfound++;
if (signum)
prsignal(pr, signum);
}
}
return (nfound ? 0 : ESRCH);
}
#define CANDELIVER(uid, euid, pr) \
(euid == 0 || \
(uid) == (pr)->ps_ucred->cr_ruid || \
(uid) == (pr)->ps_ucred->cr_svuid || \
(uid) == (pr)->ps_ucred->cr_uid || \
(euid) == (pr)->ps_ucred->cr_ruid || \
(euid) == (pr)->ps_ucred->cr_svuid || \
(euid) == (pr)->ps_ucred->cr_uid)
#define CANSIGIO(cr, pr) \
CANDELIVER((cr)->cr_ruid, (cr)->cr_uid, (pr))
/*
* Send a signal to a process group. If checktty is 1,
* limit to members which have a controlling terminal.
*/
void
pgsignal(struct pgrp *pgrp, int signum, int checkctty)
{
struct process *pr;
if (pgrp)
LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist)
if (checkctty == 0 || pr->ps_flags & PS_CONTROLT)
prsignal(pr, signum);
}
/*
* Send a SIGIO or SIGURG signal to a process or process group using stored
* credentials rather than those of the current process.
*/
void
pgsigio(struct sigio_ref *sir, int sig, int checkctty)
{
struct process *pr;
struct sigio *sigio;
if (sir->sir_sigio == NULL)
return;
KERNEL_LOCK();
mtx_enter(&sigio_lock);
sigio = sir->sir_sigio;
if (sigio == NULL)
goto out;
if (sigio->sio_pgid > 0) {
if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc))
prsignal(sigio->sio_proc, sig);
} else if (sigio->sio_pgid < 0) {
LIST_FOREACH(pr, &sigio->sio_pgrp->pg_members, ps_pglist) {
if (CANSIGIO(sigio->sio_ucred, pr) &&
(checkctty == 0 || (pr->ps_flags & PS_CONTROLT)))
prsignal(pr, sig);
}
}
out:
mtx_leave(&sigio_lock);
KERNEL_UNLOCK();
}
/*
* Recalculate the signal mask and reset the signal disposition after
* usermode frame for delivery is formed.
*/
void
postsig_done(struct proc *p, int signum, struct sigacts *ps)
{
int mask = sigmask(signum);
KERNEL_ASSERT_LOCKED();
p->p_ru.ru_nsignals++;
atomic_setbits_int(&p->p_sigmask, ps->ps_catchmask[signum]);
if ((ps->ps_sigreset & mask) != 0) {
ps->ps_sigcatch &= ~mask;
if (signum != SIGCONT && sigprop[signum] & SA_IGNORE)
ps->ps_sigignore |= mask;
ps->ps_sigact[signum] = SIG_DFL;
}
}
/*
* Send a signal caused by a trap to the current thread
* If it will be caught immediately, deliver it with correct code.
* Otherwise, post it normally.
*/
void
trapsignal(struct proc *p, int signum, u_long trapno, int code,
union sigval sigval)
{
struct process *pr = p->p_p;
struct sigacts *ps = pr->ps_sigacts;
int mask;
switch (signum) {
case SIGILL:
case SIGBUS:
case SIGSEGV:
pr->ps_acflag |= ATRAP;
break;
}
mask = sigmask(signum);
if ((pr->ps_flags & PS_TRACED) == 0 &&
(ps->ps_sigcatch & mask) != 0 &&
(p->p_sigmask & mask) == 0) {
siginfo_t si;
initsiginfo(&si, signum, trapno, code, sigval);
#ifdef KTRACE
if (KTRPOINT(p, KTR_PSIG)) {
ktrpsig(p, signum, ps->ps_sigact[signum],
p->p_sigmask, code, &si);
}
#endif
sendsig(ps->ps_sigact[signum], signum, p->p_sigmask, &si);
postsig_done(p, signum, ps);
} else {
p->p_sisig = signum;
p->p_sitrapno = trapno; /* XXX for core dump/debugger */
p->p_sicode = code;
p->p_sigval = sigval;
/*
* Signals like SIGBUS and SIGSEGV should not, when
* generated by the kernel, be ignorable or blockable.
* If it is and we're not being traced, then just kill
* the process.
*/
if ((pr->ps_flags & PS_TRACED) == 0 &&
(sigprop[signum] & SA_KILL) &&
((p->p_sigmask & mask) || (ps->ps_sigignore & mask)))
sigexit(p, signum);
ptsignal(p, signum, STHREAD);
}
}
/*
* Send the signal to the process. If the signal has an action, the action
* is usually performed by the target process rather than the caller; we add
* the signal to the set of pending signals for the process.
*
* Exceptions:
* o When a stop signal is sent to a sleeping process that takes the
* default action, the process is stopped without awakening it.
* o SIGCONT restarts stopped processes (or puts them back to sleep)
* regardless of the signal action (eg, blocked or ignored).
*
* Other ignored signals are discarded immediately.
*/
void
psignal(struct proc *p, int signum)
{
ptsignal(p, signum, SPROCESS);
}
/*
* type = SPROCESS process signal, can be diverted (sigwait())
* type = STHREAD thread signal, but should be propagated if unhandled
* type = SPROPAGATED propagated to this thread, so don't propagate again
*/
void
ptsignal(struct proc *p, int signum, enum signal_type type)
{
int s, prop;
sig_t action;
int mask;
int *siglist;
struct process *pr = p->p_p;
struct proc *q;
int wakeparent = 0;
KERNEL_ASSERT_LOCKED();
#ifdef DIAGNOSTIC
if ((u_int)signum >= NSIG || signum == 0)
panic("psignal signal number");
#endif
/* Ignore signal if the target process is exiting */
if (pr->ps_flags & PS_EXITING)
return;
mask = sigmask(signum);
if (type == SPROCESS) {
/* Accept SIGKILL to coredumping processes */
if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) {
atomic_setbits_int(&pr->ps_siglist, mask);
return;
}
/*
* If the current thread can process the signal
* immediately (it's unblocked) then have it take it.
*/
q = curproc;
if (q != NULL && q->p_p == pr && (q->p_flag & P_WEXIT) == 0 &&
(q->p_sigmask & mask) == 0)
p = q;
else {
/*
* A process-wide signal can be diverted to a
* different thread that's in sigwait() for this
* signal. If there isn't such a thread, then
* pick a thread that doesn't have it blocked so
* that the stop/kill consideration isn't
* delayed. Otherwise, mark it pending on the
* main thread.
*/
TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) {
/* ignore exiting threads */
if (q->p_flag & P_WEXIT)
continue;
/* skip threads that have the signal blocked */
if ((q->p_sigmask & mask) != 0)
continue;
/* okay, could send to this thread */
p = q;
/*
* sigsuspend, sigwait, ppoll/pselect, etc?
* Definitely go to this thread, as it's
* already blocked in the kernel.
*/
if (q->p_flag & P_SIGSUSPEND)
break;
}
}
}
if (type != SPROPAGATED)
KNOTE(&pr->ps_klist, NOTE_SIGNAL | signum);
prop = sigprop[signum];
/*
* If proc is traced, always give parent a chance.
*/
if (pr->ps_flags & PS_TRACED) {
action = SIG_DFL;
} else {
/*
* If the signal is being ignored,
* then we forget about it immediately.
* (Note: we don't set SIGCONT in ps_sigignore,
* and if it is set to SIG_IGN,
* action will be SIG_DFL here.)
*/
if (pr->ps_sigacts->ps_sigignore & mask)
return;
if (p->p_sigmask & mask) {
action = SIG_HOLD;
} else if (pr->ps_sigacts->ps_sigcatch & mask) {
action = SIG_CATCH;
} else {
action = SIG_DFL;
if (prop & SA_KILL && pr->ps_nice > NZERO)
pr->ps_nice = NZERO;
/*
* If sending a tty stop signal to a member of an
* orphaned process group, discard the signal here if
* the action is default; don't stop the process below
* if sleeping, and don't clear any pending SIGCONT.
*/
if (prop & SA_TTYSTOP && pr->ps_pgrp->pg_jobc == 0)
return;
}
}
/*
* If delivered to process, mark as pending there. Continue and stop
* signals will be propagated to all threads. So they are always
* marked at thread level.
*/
siglist = (type == SPROCESS) ? &pr->ps_siglist : &p->p_siglist;
if (prop & SA_CONT) {
siglist = &p->p_siglist;
atomic_clearbits_int(siglist, stopsigmask);
}
if (prop & SA_STOP) {
siglist = &p->p_siglist;
atomic_clearbits_int(siglist, contsigmask);
atomic_clearbits_int(&p->p_flag, P_CONTINUED);
}
atomic_setbits_int(siglist, mask);
/*
* XXX delay processing of SA_STOP signals unless action == SIG_DFL?
*/
if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED)
TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link)
if (q != p)
ptsignal(q, signum, SPROPAGATED);
/*
* Defer further processing for signals which are held,
* except that stopped processes must be continued by SIGCONT.
*/
if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || p->p_stat != SSTOP))
return;
SCHED_LOCK(s);
switch (p->p_stat) {
case SSLEEP:
/*
* If process is sleeping uninterruptibly
* we can't interrupt the sleep... the signal will
* be noticed when the process returns through
* trap() or syscall().
*/
if ((p->p_flag & P_SINTR) == 0)
goto out;
/*
* Process is sleeping and traced... make it runnable
* so it can discover the signal in issignal() and stop
* for the parent.
*/
if (pr->ps_flags & PS_TRACED)
goto run;
/*
* If SIGCONT is default (or ignored) and process is
* asleep, we are finished; the process should not
* be awakened.
*/
if ((prop & SA_CONT) && action == SIG_DFL) {
atomic_clearbits_int(siglist, mask);
goto out;
}
/*
* When a sleeping process receives a stop
* signal, process immediately if possible.
*/
if ((prop & SA_STOP) && action == SIG_DFL) {
/*
* If a child holding parent blocked,
* stopping could cause deadlock.
*/
if (pr->ps_flags & PS_PPWAIT)
goto out;
atomic_clearbits_int(siglist, mask);
pr->ps_xsig = signum;
proc_stop(p, 0);
goto out;
}
/*
* All other (caught or default) signals
* cause the process to run.
*/
goto runfast;
/*NOTREACHED*/
case SSTOP:
/*
* If traced process is already stopped,
* then no further action is necessary.
*/
if (pr->ps_flags & PS_TRACED)
goto out;
/*
* Kill signal always sets processes running.
*/
if (signum == SIGKILL) {
atomic_clearbits_int(&p->p_flag, P_SUSPSIG);
goto runfast;
}
if (prop & SA_CONT) {
/*
* If SIGCONT is default (or ignored), we continue the
* process but don't leave the signal in p_siglist, as
* it has no further action. If SIGCONT is held, we
* continue the process and leave the signal in
* p_siglist. If the process catches SIGCONT, let it
* handle the signal itself. If it isn't waiting on
* an event, then it goes back to run state.
* Otherwise, process goes back to sleep state.
*/
atomic_setbits_int(&p->p_flag, P_CONTINUED);
atomic_clearbits_int(&p->p_flag, P_SUSPSIG);
wakeparent = 1;
if (action == SIG_DFL)
atomic_clearbits_int(siglist, mask);
if (action == SIG_CATCH)
goto runfast;
if (p->p_wchan == 0)
goto run;
p->p_stat = SSLEEP;
goto out;
}
if (prop & SA_STOP) {
/*
* Already stopped, don't need to stop again.
* (If we did the shell could get confused.)
*/
atomic_clearbits_int(siglist, mask);
goto out;
}
/*
* If process is sleeping interruptibly, then simulate a
* wakeup so that when it is continued, it will be made
* runnable and can look at the signal. But don't make
* the process runnable, leave it stopped.
*/
if (p->p_flag & P_SINTR)
unsleep(p);
goto out;
case SONPROC:
signotify(p);
/* FALLTHROUGH */
default:
/*
* SRUN, SIDL, SDEAD do nothing with the signal,
* other than kicking ourselves if we are running.
* It will either never be noticed, or noticed very soon.
*/
goto out;
}
/*NOTREACHED*/
runfast:
/*
* Raise priority to at least PUSER.
*/
if (p->p_usrpri > PUSER)
p->p_usrpri = PUSER;
run:
setrunnable(p);
out:
SCHED_UNLOCK(s);
if (wakeparent)
wakeup(pr->ps_pptr);
}
/*
* If the current process has received a signal (should be caught or cause
* termination, should interrupt current syscall), return the signal number.
* Stop signals with default action are processed immediately, then cleared;
* they aren't returned. This is checked after each entry to the system for
* a syscall or trap (though this can usually be done without calling issignal
* by checking the pending signal masks in the CURSIG macro.) The normal call
* sequence is
*
* while (signum = CURSIG(curproc))
* postsig(signum);
*
* Assumes that if the P_SINTR flag is set, we're holding both the
* kernel and scheduler locks.
*/
int
issignal(struct proc *p)
{
struct process *pr = p->p_p;
int signum, mask, prop;
int dolock = (p->p_flag & P_SINTR) == 0;
int s;
for (;;) {
mask = SIGPENDING(p);
if (pr->ps_flags & PS_PPWAIT)
mask &= ~stopsigmask;
if (mask == 0) /* no signal to send */
return (0);
signum = ffs((long)mask);
mask = sigmask(signum);
atomic_clearbits_int(&p->p_siglist, mask);
atomic_clearbits_int(&pr->ps_siglist, mask);
/*
* We should see pending but ignored signals
* only if PS_TRACED was on when they were posted.
*/
if (mask & pr->ps_sigacts->ps_sigignore &&
(pr->ps_flags & PS_TRACED) == 0)
continue;
/*
* If traced, always stop, and stay stopped until released
* by the debugger. If our parent process is waiting for
* us, don't hang as we could deadlock.
*/
if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) &&
signum != SIGKILL) {
pr->ps_xsig = signum;
if (dolock)
KERNEL_LOCK();
single_thread_set(p, SINGLE_PTRACE, 0);
if (dolock)
KERNEL_UNLOCK();
if (dolock)
SCHED_LOCK(s);
proc_stop(p, 1);
if (dolock)
SCHED_UNLOCK(s);
if (dolock)
KERNEL_LOCK();
single_thread_clear(p, 0);
if (dolock)
KERNEL_UNLOCK();
/*
* If we are no longer being traced, or the parent
* didn't give us a signal, look for more signals.
*/
if ((pr->ps_flags & PS_TRACED) == 0 ||
pr->ps_xsig == 0)
continue;
/*
* If the new signal is being masked, look for other
* signals.
*/
signum = pr->ps_xsig;
mask = sigmask(signum);
if ((p->p_sigmask & mask) != 0)
continue;
/* take the signal! */
atomic_clearbits_int(&p->p_siglist, mask);
atomic_clearbits_int(&pr->ps_siglist, mask);
}
prop = sigprop[signum];
/*
* Decide whether the signal should be returned.
* Return the signal's number, or fall through
* to clear it from the pending mask.
*/
switch ((long)pr->ps_sigacts->ps_sigact[signum]) {
case (long)SIG_DFL:
/*
* Don't take default actions on system processes.
*/
if (pr->ps_pid <= 1) {
#ifdef DIAGNOSTIC
/*
* Are you sure you want to ignore SIGSEGV
* in init? XXX
*/
printf("Process (pid %d) got signal"
" %d\n", pr->ps_pid, signum);
#endif
break; /* == ignore */
}
/*
* If there is a pending stop signal to process
* with default action, stop here,
* then clear the signal. However,
* if process is member of an orphaned
* process group, ignore tty stop signals.
*/
if (prop & SA_STOP) {
if (pr->ps_flags & PS_TRACED ||
(pr->ps_pgrp->pg_jobc == 0 &&
prop & SA_TTYSTOP))
break; /* == ignore */
pr->ps_xsig = signum;
if (dolock)
SCHED_LOCK(s);
proc_stop(p, 1);
if (dolock)
SCHED_UNLOCK(s);
break;
} else if (prop & SA_IGNORE) {
/*
* Except for SIGCONT, shouldn't get here.
* Default action is to ignore; drop it.
*/
break; /* == ignore */
} else
goto keep;
/*NOTREACHED*/
case (long)SIG_IGN:
/*
* Masking above should prevent us ever trying
* to take action on an ignored signal other
* than SIGCONT, unless process is traced.
*/
if ((prop & SA_CONT) == 0 &&
(pr->ps_flags & PS_TRACED) == 0)
printf("issignal\n");
break; /* == ignore */
default:
/*
* This signal has an action, let
* postsig() process it.
*/
goto keep;
}
}
/* NOTREACHED */
keep:
atomic_setbits_int(&p->p_siglist, mask); /*leave the signal for later */
return (signum);
}
/*
* Put the argument process into the stopped state and notify the parent
* via wakeup. Signals are handled elsewhere. The process must not be
* on the run queue.
*/
void
proc_stop(struct proc *p, int sw)
{
struct process *pr = p->p_p;
#ifdef MULTIPROCESSOR
SCHED_ASSERT_LOCKED();
#endif
p->p_stat = SSTOP;
atomic_clearbits_int(&pr->ps_flags, PS_WAITED);
atomic_setbits_int(&pr->ps_flags, PS_STOPPED);
atomic_setbits_int(&p->p_flag, P_SUSPSIG);
/*
* We need this soft interrupt to be handled fast.
* Extra calls to softclock don't hurt.
*/
softintr_schedule(proc_stop_si);
if (sw)
mi_switch();
}
/*
* Called from a soft interrupt to send signals to the parents of stopped
* processes.
* We can't do this in proc_stop because it's called with nasty locks held
* and we would need recursive scheduler lock to deal with that.
*/
void
proc_stop_sweep(void *v)
{
struct process *pr;
LIST_FOREACH(pr, &allprocess, ps_list) {
if ((pr->ps_flags & PS_STOPPED) == 0)
continue;
atomic_clearbits_int(&pr->ps_flags, PS_STOPPED);
if ((pr->ps_pptr->ps_sigacts->ps_flags & SAS_NOCLDSTOP) == 0)
prsignal(pr->ps_pptr, SIGCHLD);
wakeup(pr->ps_pptr);
}
}
/*
* Take the action for the specified signal
* from the current set of pending signals.
*/
void
postsig(struct proc *p, int signum)
{
struct process *pr = p->p_p;
struct sigacts *ps = pr->ps_sigacts;
sig_t action;
u_long trapno;
int mask, returnmask;
siginfo_t si;
union sigval sigval;
int s, code;
KASSERT(signum != 0);
KERNEL_ASSERT_LOCKED();
mask = sigmask(signum);
atomic_clearbits_int(&p->p_siglist, mask);
action = ps->ps_sigact[signum];
sigval.sival_ptr = 0;
if (p->p_sisig != signum) {
trapno = 0;
code = SI_USER;
sigval.sival_ptr = 0;
} else {
trapno = p->p_sitrapno;
code = p->p_sicode;
sigval = p->p_sigval;
}
initsiginfo(&si, signum, trapno, code, sigval);
#ifdef KTRACE
if (KTRPOINT(p, KTR_PSIG)) {
ktrpsig(p, signum, action, p->p_flag & P_SIGSUSPEND ?
p->p_oldmask : p->p_sigmask, code, &si);
}
#endif
if (action == SIG_DFL) {
/*
* Default action, where the default is to kill
* the process. (Other cases were ignored above.)
*/
sigexit(p, signum);
/* NOTREACHED */
} else {
/*
* If we get here, the signal must be caught.
*/
#ifdef DIAGNOSTIC
if (action == SIG_IGN || (p->p_sigmask & mask))
panic("postsig action");
#endif
/*
* Set the new mask value and also defer further
* occurrences of this signal.
*
* Special case: user has done a sigpause. Here the
* current mask is not of interest, but rather the
* mask from before the sigpause is what we want
* restored after the signal processing is completed.
*/
#ifdef MULTIPROCESSOR
s = splsched();
#else
s = splhigh();
#endif
if (p->p_flag & P_SIGSUSPEND) {
atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND);
returnmask = p->p_oldmask;
} else {
returnmask = p->p_sigmask;
}
if (p->p_sisig == signum) {
p->p_sisig = 0;
p->p_sitrapno = 0;
p->p_sicode = SI_USER;
p->p_sigval.sival_ptr = NULL;
}
sendsig(action, signum, returnmask, &si);
postsig_done(p, signum, ps);
splx(s);
}
}
/*
* Force the current process to exit with the specified signal, dumping core
* if appropriate. We bypass the normal tests for masked and caught signals,
* allowing unrecoverable failures to terminate the process without changing
* signal state. Mark the accounting record with the signal termination.
* If dumping core, save the signal number for the debugger. Calls exit and
* does not return.
*/
void
sigexit(struct proc *p, int signum)
{
/* Mark process as going away */
atomic_setbits_int(&p->p_flag, P_WEXIT);
p->p_p->ps_acflag |= AXSIG;
if (sigprop[signum] & SA_CORE) {
p->p_sisig = signum;
/* if there are other threads, pause them */
if (P_HASSIBLING(p))
single_thread_set(p, SINGLE_SUSPEND, 0);
if (coredump(p) == 0)
signum |= WCOREFLAG;
}
exit1(p, 0, signum, EXIT_NORMAL);
/* NOTREACHED */
}
int nosuidcoredump = 1;
struct coredump_iostate {
struct proc *io_proc;
struct vnode *io_vp;
struct ucred *io_cred;
off_t io_offset;
};
/*
* Dump core, into a file named "progname.core", unless the process was
* setuid/setgid.
*/
int
coredump(struct proc *p)
{
#ifdef SMALL_KERNEL
return EPERM;
#else
struct process *pr = p->p_p;
struct vnode *vp;
struct ucred *cred = p->p_ucred;
struct vmspace *vm = p->p_vmspace;
struct nameidata nd;
struct vattr vattr;
struct coredump_iostate io;
int error, len, incrash = 0;
char *name;
const char *dir = "/var/crash";
if (pr->ps_emul->e_coredump == NULL)
return (EINVAL);
atomic_setbits_int(&pr->ps_flags, PS_COREDUMP);
/* Don't dump if will exceed file size limit. */
if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= lim_cur(RLIMIT_CORE))
return (EFBIG);
name = pool_get(&namei_pool, PR_WAITOK);
/*
* If the process has inconsistent uids, nosuidcoredump
* determines coredump placement policy.
*/
if (((pr->ps_flags & PS_SUGID) && (error = suser(p))) ||
((pr->ps_flags & PS_SUGID) && nosuidcoredump)) {
if (nosuidcoredump == 3) {
/*
* If the program directory does not exist, dumps of
* that core will silently fail.
*/
len = snprintf(name, MAXPATHLEN, "%s/%s/%u.core",
dir, pr->ps_comm, pr->ps_pid);
incrash = KERNELPATH;
} else if (nosuidcoredump == 2) {
len = snprintf(name, MAXPATHLEN, "%s/%s.core",
dir, pr->ps_comm);
incrash = KERNELPATH;
} else {
pool_put(&namei_pool, name);
return (EPERM);
}
} else
len = snprintf(name, MAXPATHLEN, "%s.core", pr->ps_comm);
if (len >= MAXPATHLEN) {
pool_put(&namei_pool, name);
return (EACCES);
}
/*
* Control the UID used to write out. The normal case uses
* the real UID. If the sugid case is going to write into the
* controlled directory, we do so as root.
*/
if (incrash == 0) {
cred = crdup(cred);
cred->cr_uid = cred->cr_ruid;
cred->cr_gid = cred->cr_rgid;
} else {
if (p->p_fd->fd_rdir) {
vrele(p->p_fd->fd_rdir);
p->p_fd->fd_rdir = NULL;
}
p->p_ucred = crdup(p->p_ucred);
crfree(cred);
cred = p->p_ucred;
crhold(cred);
cred->cr_uid = 0;
cred->cr_gid = 0;
}
/* incrash should be 0 or KERNELPATH only */
NDINIT(&nd, 0, incrash, UIO_SYSSPACE, name, p);
error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW | O_NONBLOCK,
S_IRUSR | S_IWUSR);
if (error)
goto out;
/*
* Don't dump to non-regular files, files with links, or files
* owned by someone else.
*/
vp = nd.ni_vp;
if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) {
VOP_UNLOCK(vp);
vn_close(vp, FWRITE, cred, p);
goto out;
}
if (vp->v_type != VREG || vattr.va_nlink != 1 ||
vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) ||
vattr.va_uid != cred->cr_uid) {
error = EACCES;
VOP_UNLOCK(vp);
vn_close(vp, FWRITE, cred, p);
goto out;
}
VATTR_NULL(&vattr);
vattr.va_size = 0;
VOP_SETATTR(vp, &vattr, cred, p);
pr->ps_acflag |= ACORE;
io.io_proc = p;
io.io_vp = vp;
io.io_cred = cred;
io.io_offset = 0;
VOP_UNLOCK(vp);
vref(vp);
error = vn_close(vp, FWRITE, cred, p);
if (error == 0)
error = (*pr->ps_emul->e_coredump)(p, &io);
vrele(vp);
out:
crfree(cred);
pool_put(&namei_pool, name);
return (error);
#endif
}
#ifndef SMALL_KERNEL
int
coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len)
{
struct coredump_iostate *io = cookie;
off_t coffset = 0;
size_t csize;
int chunk, error;
csize = len;
do {
if (sigmask(SIGKILL) &
(io->io_proc->p_siglist | io->io_proc->p_p->ps_siglist))
return (EINTR);
/* Rest of the loop sleeps with lock held, so... */
yield();
chunk = MIN(csize, MAXPHYS);
error = vn_rdwr(UIO_WRITE, io->io_vp,
(caddr_t)data + coffset, chunk,
io->io_offset + coffset, segflg,
IO_UNIT, io->io_cred, NULL, io->io_proc);
if (error) {
struct process *pr = io->io_proc->p_p;
if (error == ENOSPC)
log(LOG_ERR,
"coredump of %s(%d) failed, filesystem full\n",
pr->ps_comm, pr->ps_pid);
else
log(LOG_ERR,
"coredump of %s(%d), write failed: errno %d\n",
pr->ps_comm, pr->ps_pid, error);
return (error);
}
coffset += chunk;
csize -= chunk;
} while (csize > 0);
io->io_offset += len;
return (0);
}
void
coredump_unmap(void *cookie, vaddr_t start, vaddr_t end)
{
struct coredump_iostate *io = cookie;
uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end);
}
#endif /* !SMALL_KERNEL */
/*
* Nonexistent system call-- signal process (may want to handle it).
* Flag error in case process won't see signal immediately (blocked or ignored).
*/
int
sys_nosys(struct proc *p, void *v, register_t *retval)
{
ptsignal(p, SIGSYS, STHREAD);
return (ENOSYS);
}
int
sys___thrsigdivert(struct proc *p, void *v, register_t *retval)
{
static int sigwaitsleep;
struct sys___thrsigdivert_args /* {
syscallarg(sigset_t) sigmask;
syscallarg(siginfo_t *) info;
syscallarg(const struct timespec *) timeout;
} */ *uap = v;
struct process *pr = p->p_p;
sigset_t *m;
sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask;
siginfo_t si;
uint64_t nsecs = INFSLP;
int timeinvalid = 0;
int error = 0;
memset(&si, 0, sizeof(si));
if (SCARG(uap, timeout) != NULL) {
struct timespec ts;
if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0)
return (error);
#ifdef KTRACE
if (KTRPOINT(p, KTR_STRUCT))
ktrreltimespec(p, &ts);
#endif
if (!timespecisvalid(&ts))
timeinvalid = 1;
else
nsecs = TIMESPEC_TO_NSEC(&ts);
}
dosigsuspend(p, p->p_sigmask &~ mask);
for (;;) {
si.si_signo = CURSIG(p);
if (si.si_signo != 0) {
sigset_t smask = sigmask(si.si_signo);
if (smask & mask) {
if (p->p_siglist & smask)
m = &p->p_siglist;
else if (pr->ps_siglist & smask)
m = &pr->ps_siglist;
else {
/* signal got eaten by someone else? */
continue;
}
atomic_clearbits_int(m, smask);
error = 0;
break;
}
}
/* per-POSIX, delay this error until after the above */
if (timeinvalid)
error = EINVAL;
if (SCARG(uap, timeout) != NULL && nsecs == INFSLP)
error = EAGAIN;
if (error != 0)
break;
error = tsleep_nsec(&sigwaitsleep, PPAUSE|PCATCH, "sigwait",
nsecs);
}
if (error == 0) {
*retval = si.si_signo;
if (SCARG(uap, info) != NULL)
error = copyout(&si, SCARG(uap, info), sizeof(si));
} else if (error == ERESTART && SCARG(uap, timeout) != NULL) {
/*
* Restarting is wrong if there's a timeout, as it'll be
* for the same interval again
*/
error = EINTR;
}
return (error);
}
void
initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val)
{
memset(si, 0, sizeof(*si));
si->si_signo = sig;
si->si_code = code;
if (code == SI_USER) {
si->si_value = val;
} else {
switch (sig) {
case SIGSEGV:
case SIGILL:
case SIGBUS:
case SIGFPE:
si->si_addr = val.sival_ptr;
si->si_trapno = trapno;
break;
case SIGXFSZ:
break;
}
}
}
int
filt_sigattach(struct knote *kn)
{
struct process *pr = curproc->p_p;
if (kn->kn_id >= NSIG)
return EINVAL;
kn->kn_ptr.p_process = pr;
kn->kn_flags |= EV_CLEAR; /* automatically set */
/* XXX lock the proc here while adding to the list? */
SLIST_INSERT_HEAD(&pr->ps_klist, kn, kn_selnext);
return (0);
}
void
filt_sigdetach(struct knote *kn)
{
struct process *pr = kn->kn_ptr.p_process;
SLIST_REMOVE(&pr->ps_klist, kn, knote, kn_selnext);
}
/*
* signal knotes are shared with proc knotes, so we apply a mask to
* the hint in order to differentiate them from process hints. This
* could be avoided by using a signal-specific knote list, but probably
* isn't worth the trouble.
*/
int
filt_signal(struct knote *kn, long hint)
{
if (hint & NOTE_SIGNAL) {
hint &= ~NOTE_SIGNAL;
if (kn->kn_id == hint)
kn->kn_data++;
}
return (kn->kn_data != 0);
}
void
userret(struct proc *p)
{
int signum;
/* send SIGPROF or SIGVTALRM if their timers interrupted this thread */
if (p->p_flag & P_PROFPEND) {
atomic_clearbits_int(&p->p_flag, P_PROFPEND);
KERNEL_LOCK();
psignal(p, SIGPROF);
KERNEL_UNLOCK();
}
if (p->p_flag & P_ALRMPEND) {
atomic_clearbits_int(&p->p_flag, P_ALRMPEND);
KERNEL_LOCK();
psignal(p, SIGVTALRM);
KERNEL_UNLOCK();
}
if (SIGPENDING(p) != 0) {
KERNEL_LOCK();
while ((signum = CURSIG(p)) != 0)
postsig(p, signum);
KERNEL_UNLOCK();
}
/*
* If P_SIGSUSPEND is still set here, then we still need to restore
* the original sigmask before returning to userspace. Also, this
* might unmask some pending signals, so we need to check a second
* time for signals to post.
*/
if (p->p_flag & P_SIGSUSPEND) {
atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND);
p->p_sigmask = p->p_oldmask;
KERNEL_LOCK();
while ((signum = CURSIG(p)) != 0)
postsig(p, signum);
KERNEL_UNLOCK();
}
if (p->p_flag & P_SUSPSINGLE) {
KERNEL_LOCK();
single_thread_check(p, 0);
KERNEL_UNLOCK();
}
WITNESS_WARN(WARN_PANIC, NULL, "userret: returning");
p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri;
}
int
single_thread_check(struct proc *p, int deep)
{
struct process *pr = p->p_p;
if (pr->ps_single != NULL && pr->ps_single != p) {
do {
int s;
/* if we're in deep, we need to unwind to the edge */
if (deep) {
if (pr->ps_flags & PS_SINGLEUNWIND)
return (ERESTART);
if (pr->ps_flags & PS_SINGLEEXIT)
return (EINTR);
}
if (--pr->ps_singlecount == 0)
wakeup(&pr->ps_singlecount);
if (pr->ps_flags & PS_SINGLEEXIT)
exit1(p, 0, 0, EXIT_THREAD_NOCHECK);
/* not exiting and don't need to unwind, so suspend */
SCHED_LOCK(s);
p->p_stat = SSTOP;
mi_switch();
SCHED_UNLOCK(s);
} while (pr->ps_single != NULL);
}
return (0);
}
/*
* Stop other threads in the process. The mode controls how and
* where the other threads should stop:
* - SINGLE_SUSPEND: stop wherever they are, will later either be told to exit
* (by setting to SINGLE_EXIT) or be released (via single_thread_clear())
* - SINGLE_PTRACE: stop wherever they are, will wait for them to stop
* later (via single_thread_wait()) and released as with SINGLE_SUSPEND
* - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit
* or released as with SINGLE_SUSPEND
* - SINGLE_EXIT: unwind to kernel boundary and exit
*/
int
single_thread_set(struct proc *p, enum single_thread_mode mode, int deep)
{
struct process *pr = p->p_p;
struct proc *q;
int error;
KERNEL_ASSERT_LOCKED();
if ((error = single_thread_check(p, deep)))
return error;
switch (mode) {
case SINGLE_SUSPEND:
case SINGLE_PTRACE:
break;
case SINGLE_UNWIND:
atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND);
break;
case SINGLE_EXIT:
atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT);
atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND);
break;
#ifdef DIAGNOSTIC
default:
panic("single_thread_mode = %d", mode);
#endif
}
pr->ps_single = p;
pr->ps_singlecount = 0;
TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) {
int s;
if (q == p)
continue;
if (q->p_flag & P_WEXIT) {
if (mode == SINGLE_EXIT) {
SCHED_LOCK(s);
if (q->p_stat == SSTOP) {
setrunnable(q);
pr->ps_singlecount++;
}
SCHED_UNLOCK(s);
}
continue;
}
SCHED_LOCK(s);
atomic_setbits_int(&q->p_flag, P_SUSPSINGLE);
switch (q->p_stat) {
case SIDL:
case SRUN:
pr->ps_singlecount++;
break;
case SSLEEP:
/* if it's not interruptible, then just have to wait */
if (q->p_flag & P_SINTR) {
/* merely need to suspend? just stop it */
if (mode == SINGLE_SUSPEND ||
mode == SINGLE_PTRACE) {
q->p_stat = SSTOP;
break;
}
/* need to unwind or exit, so wake it */
setrunnable(q);
}
pr->ps_singlecount++;
break;
case SSTOP:
if (mode == SINGLE_EXIT) {
setrunnable(q);
pr->ps_singlecount++;
}
break;
case SDEAD:
break;
case SONPROC:
pr->ps_singlecount++;
signotify(q);
break;
}
SCHED_UNLOCK(s);
}
if (mode != SINGLE_PTRACE)
single_thread_wait(pr);
return 0;
}
void
single_thread_wait(struct process *pr)
{
/* wait until they're all suspended */
while (pr->ps_singlecount > 0)
tsleep_nsec(&pr->ps_singlecount, PWAIT, "suspend", INFSLP);
}
void
single_thread_clear(struct proc *p, int flag)
{
struct process *pr = p->p_p;
struct proc *q;
KASSERT(pr->ps_single == p);
KERNEL_ASSERT_LOCKED();
pr->ps_single = NULL;
atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT);
TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) {
int s;
if (q == p || (q->p_flag & P_SUSPSINGLE) == 0)
continue;
atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE);
/*
* if the thread was only stopped for single threading
* then clearing that either makes it runnable or puts
* it back into some sleep queue
*/
SCHED_LOCK(s);
if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) {
if (q->p_wchan == 0)
setrunnable(q);
else
q->p_stat = SSLEEP;
}
SCHED_UNLOCK(s);
}
}
void
sigio_del(struct sigiolst *rmlist)
{
struct sigio *sigio;
while ((sigio = LIST_FIRST(rmlist)) != NULL) {
LIST_REMOVE(sigio, sio_pgsigio);
crfree(sigio->sio_ucred);
free(sigio, M_SIGIO, sizeof(*sigio));
}
}
void
sigio_unlink(struct sigio_ref *sir, struct sigiolst *rmlist)
{
struct sigio *sigio;
MUTEX_ASSERT_LOCKED(&sigio_lock);
sigio = sir->sir_sigio;
if (sigio != NULL) {
KASSERT(sigio->sio_myref == sir);
sir->sir_sigio = NULL;
if (sigio->sio_pgid > 0)
sigio->sio_proc = NULL;
else
sigio->sio_pgrp = NULL;
LIST_REMOVE(sigio, sio_pgsigio);
LIST_INSERT_HEAD(rmlist, sigio, sio_pgsigio);
}
}
void
sigio_free(struct sigio_ref *sir)
{
struct sigiolst rmlist;
if (sir->sir_sigio == NULL)
return;
LIST_INIT(&rmlist);
mtx_enter(&sigio_lock);
sigio_unlink(sir, &rmlist);
mtx_leave(&sigio_lock);
sigio_del(&rmlist);
}
void
sigio_freelist(struct sigiolst *sigiolst)
{
struct sigiolst rmlist;
struct sigio *sigio;
if (LIST_EMPTY(sigiolst))
return;
LIST_INIT(&rmlist);
mtx_enter(&sigio_lock);
while ((sigio = LIST_FIRST(sigiolst)) != NULL)
sigio_unlink(sigio->sio_myref, &rmlist);
mtx_leave(&sigio_lock);
sigio_del(&rmlist);
}
int
sigio_setown(struct sigio_ref *sir, u_long cmd, caddr_t data)
{
struct sigiolst rmlist;
struct proc *p = curproc;
struct pgrp *pgrp = NULL;
struct process *pr = NULL;
struct sigio *sigio;
int error;
pid_t pgid = *(int *)data;
if (pgid == 0) {
sigio_free(sir);
return (0);
}
if (cmd == TIOCSPGRP) {
if (pgid < 0)
return (EINVAL);
pgid = -pgid;
}
sigio = malloc(sizeof(*sigio), M_SIGIO, M_WAITOK);
sigio->sio_pgid = pgid;
sigio->sio_ucred = crhold(p->p_ucred);
sigio->sio_myref = sir;
LIST_INIT(&rmlist);
/*
* The kernel lock, and not sleeping between prfind()/pgfind() and
* linking of the sigio ensure that the process or process group does
* not disappear unexpectedly.
*/
KERNEL_LOCK();
mtx_enter(&sigio_lock);
if (pgid > 0) {
pr = prfind(pgid);
if (pr == NULL) {
error = ESRCH;
goto fail;
}
/*
* Policy - Don't allow a process to FSETOWN a process
* in another session.
*
* Remove this test to allow maximum flexibility or
* restrict FSETOWN to the current process or process
* group for maximum safety.
*/
if (pr->ps_session != p->p_p->ps_session) {
error = EPERM;
goto fail;
}
if ((pr->ps_flags & PS_EXITING) != 0) {
error = ESRCH;
goto fail;
}
} else /* if (pgid < 0) */ {
pgrp = pgfind(-pgid);
if (pgrp == NULL) {
error = ESRCH;
goto fail;
}
/*
* Policy - Don't allow a process to FSETOWN a process
* in another session.
*
* Remove this test to allow maximum flexibility or
* restrict FSETOWN to the current process or process
* group for maximum safety.
*/
if (pgrp->pg_session != p->p_p->ps_session) {
error = EPERM;
goto fail;
}
}
if (pgid > 0) {
sigio->sio_proc = pr;
LIST_INSERT_HEAD(&pr->ps_sigiolst, sigio, sio_pgsigio);
} else {
sigio->sio_pgrp = pgrp;
LIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio);
}
sigio_unlink(sir, &rmlist);
sir->sir_sigio = sigio;
mtx_leave(&sigio_lock);
KERNEL_UNLOCK();
sigio_del(&rmlist);
return (0);
fail:
mtx_leave(&sigio_lock);
KERNEL_UNLOCK();
crfree(sigio->sio_ucred);
free(sigio, M_SIGIO, sizeof(*sigio));
return (error);
}
void
sigio_getown(struct sigio_ref *sir, u_long cmd, caddr_t data)
{
struct sigio *sigio;
pid_t pgid = 0;
mtx_enter(&sigio_lock);
sigio = sir->sir_sigio;
if (sigio != NULL)
pgid = sigio->sio_pgid;
mtx_leave(&sigio_lock);
if (cmd == TIOCGPGRP)
pgid = -pgid;
*(int *)data = pgid;
}
void
sigio_copy(struct sigio_ref *dst, struct sigio_ref *src)
{
struct sigiolst rmlist;
struct sigio *newsigio, *sigio;
sigio_free(dst);
if (src->sir_sigio == NULL)
return;
newsigio = malloc(sizeof(*newsigio), M_SIGIO, M_WAITOK);
LIST_INIT(&rmlist);
mtx_enter(&sigio_lock);
sigio = src->sir_sigio;
if (sigio == NULL) {
mtx_leave(&sigio_lock);
free(newsigio, M_SIGIO, sizeof(*newsigio));
return;
}
newsigio->sio_pgid = sigio->sio_pgid;
newsigio->sio_ucred = crhold(sigio->sio_ucred);
newsigio->sio_myref = dst;
if (newsigio->sio_pgid > 0) {
newsigio->sio_proc = sigio->sio_proc;
LIST_INSERT_HEAD(&newsigio->sio_proc->ps_sigiolst, newsigio,
sio_pgsigio);
} else {
newsigio->sio_pgrp = sigio->sio_pgrp;
LIST_INSERT_HEAD(&newsigio->sio_pgrp->pg_sigiolst, newsigio,
sio_pgsigio);
}
sigio_unlink(dst, &rmlist);
dst->sir_sigio = newsigio;
mtx_leave(&sigio_lock);
sigio_del(&rmlist);
}
|