Subversion Repositories planix.SVN

#include "../plan9/lib.h"
#include "../plan9/sys9.h"
#include <signal.h>
#include <setjmp.h>

/* A stack to hold pcs when signals nest */
#define MAXSIGSTACK 20
typedef struct Pcstack Pcstack;
static struct Pcstack {
        int sig;
        void (*hdlr)(int, char*, Ureg*);
        unsigned long restorepc;
        Ureg *u;
} pcstack[MAXSIGSTACK];
static int nstack = 0;

static void notecont(Ureg*, char*);

void
_notetramp(int sig, void (*hdlr)(int, char*, Ureg*), Ureg *u)
{
        Pcstack *p;

        if(nstack >= MAXSIGSTACK)
                _NOTED(1);      /* nesting too deep; just do system default */
        p = &pcstack[nstack];
        p->restorepc = u->pc;
        p->sig = sig;
        p->hdlr = hdlr;
        p->u = u;
        nstack++;
        u->pc = (unsigned long) notecont;
        _NOTED(2);      /* NSAVE: clear note but hold state */
}

static void
notecont(Ureg *u, char *s)
{
        Pcstack *p;
        void(*f)(int, char*, Ureg*);

        p = &pcstack[nstack-1];
        f = p->hdlr;
        u->pc = p->restorepc;
        nstack--;
        (*f)(p->sig, s, u);
        _NOTED(3);      /* NRSTR */
}

#define JMPBUFPC 1
#define JMPBUFSP 0

extern sigset_t _psigblocked;

void
siglongjmp(sigjmp_buf j, int ret)
{
        struct Ureg *u;

        if(j[0])
                _psigblocked = j[1];
        if(nstack == 0 || pcstack[nstack-1].u->sp > j[2+JMPBUFSP])
                longjmp(j+2, ret);
        u = pcstack[nstack-1].u;
        nstack--;
        u->ax = ret;
        if(ret == 0)
                u->ax = 1;
        u->pc = j[2+JMPBUFPC];
        u->sp = j[2+JMPBUFSP] + 4;
        _NOTED(3);      /* NRSTR */
}