1 #include "../plan9/lib.h" 2 #include "../plan9/sys9.h" 3 #include <signal.h> 4 5 /* A stack to hold pcs when signals nest */ 6 #define MAXSIGSTACK 20 7 typedef struct Pcstack Pcstack; 8 static struct Pcstack { 9 int sig; 10 void (*hdlr)(int, char*, Ureg*); 11 unsigned long restorepc; 12 } pcstack[MAXSIGSTACK]; 13 static int nstack = 0; 14 15 static void notecont(Ureg*, char*); 16 17 void 18 _notetramp(int sig, void (*hdlr)(int, char*, Ureg*), Ureg *u) 19 { 20 Pcstack *p; 21 22 if(nstack >= MAXSIGSTACK) 23 _NOTED(1); /* nesting too deep; just do system default */ 24 p = &pcstack[nstack]; 25 p->restorepc = u->pc; 26 p->sig = sig; 27 p->hdlr = hdlr; 28 nstack++; 29 u->pc = (unsigned long) notecont; 30 _NOTED(2); /* NSAVE: clear note but hold state */ 31 } 32 33 static void 34 notecont(Ureg *u, char *s) 35 { 36 Pcstack *p; 37 void(*f)(int, char*, Ureg*); 38 39 p = &pcstack[nstack-1]; 40 f = p->hdlr; 41 u->pc = p->restorepc; 42 nstack--; 43 (*f)(p->sig, s, u); 44 _NOTED(3); /* NRSTR */ 45 } 46