1 #include "../plan9/lib.h"
2 #include "../plan9/sys9.h"
3 #include <signal.h>
4 #include <setjmp.h>
5
6 /* A stack to hold pcs when signals nest */
7 #define MAXSIGSTACK 20
8 typedef struct Pcstack Pcstack;
9 static struct Pcstack {
10 int sig;
11 void (*hdlr)(int, char*, Ureg*);
12 unsigned long restorepc;
13 unsigned long restorenpc;
14 Ureg *u;
15 } pcstack[MAXSIGSTACK];
16 static int nstack = 0;
17
18 static void notecont(Ureg*, char*);
19
20 void
_notetramp(int sig,void (* hdlr)(int,char *,Ureg *),Ureg * u)21 _notetramp(int sig, void (*hdlr)(int, char*, Ureg*), Ureg *u)
22 {
23 Pcstack *p;
24
25 if(nstack >= MAXSIGSTACK)
26 _NOTED(1); /* nesting too deep; just do system default */
27 p = &pcstack[nstack];
28 p->restorepc = u->pc;
29 p->restorenpc = u->npc;
30 p->sig = sig;
31 p->hdlr = hdlr;
32 p->u = u;
33 nstack++;
34 u->pc = (unsigned long) notecont;
35 u->npc = u->pc+4;
36 _NOTED(2); /* NSAVE: clear note but hold state */
37 }
38
39 static void
notecont(Ureg * u,char * s)40 notecont(Ureg *u, char *s)
41 {
42 Pcstack *p;
43 void(*f)(int, char*, Ureg*);
44
45 p = &pcstack[nstack-1];
46 f = p->hdlr;
47 u->pc = p->restorepc;
48 u->npc = p->restorenpc;
49 nstack--;
50 (*f)(p->sig, s, u);
51 _NOTED(3); /* NRSTR */
52 }
53
54 int __noterestore(void);
55
56 #define JMPBUFPC 1
57 #define JMPBUFSP 0
58 #define JMPBUFDPC (-8)
59
60 extern sigset_t _psigblocked;
61
62 void
siglongjmp(sigjmp_buf j,int ret)63 siglongjmp(sigjmp_buf j, int ret)
64 {
65 struct Ureg *u;
66
67 if(j[0])
68 _psigblocked = j[1];
69 if(nstack == 0 || pcstack[nstack-1].u->sp > j[2+JMPBUFSP])
70 longjmp(j+2, ret);
71 u = pcstack[nstack-1].u;
72 nstack--;
73 u->r8 = ret;
74 if(ret == 0)
75 u->r8 = 1;
76 u->r9 = j[JMPBUFPC] - JMPBUFDPC;
77 u->pc = (unsigned long)__noterestore;
78 u->npc = (unsigned long)__noterestore + 4;
79 u->sp = j[JMPBUFSP];
80 _NOTED(3); /* NRSTR */
81 }
82