mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-04 09:09:56 +00:00
121 lines
2.3 KiB
C
121 lines
2.3 KiB
C
/* No copyright?!
|
|
**
|
|
** $FreeBSD$
|
|
*/
|
|
|
|
|
|
#include <sys/queue.h>
|
|
#include "doscmd.h"
|
|
|
|
/*
|
|
** Callbacks are used for chaining interrupt handlers
|
|
** off interrupt vectors
|
|
*/
|
|
|
|
struct callback {
|
|
LIST_ENTRY(callback) chain;
|
|
u_long vec;
|
|
callback_t func;
|
|
char *name;
|
|
};
|
|
|
|
LIST_HEAD(cbhead , callback) cbhead[127];
|
|
|
|
#define CBHASH(x) (((x) * 17) % 127)
|
|
|
|
/*
|
|
** Register (func) as a handler for (vec)
|
|
*/
|
|
void
|
|
register_callback(u_long vec, callback_t func, char *name)
|
|
{
|
|
struct cbhead *head;
|
|
struct callback *elm;
|
|
|
|
elm = malloc(sizeof(struct callback));
|
|
elm->vec = vec;
|
|
elm->func = func;
|
|
elm->name = name;
|
|
|
|
head = &cbhead[CBHASH(vec)];
|
|
LIST_INSERT_HEAD(head, elm, chain);
|
|
}
|
|
|
|
/*
|
|
** Find a handler for (vec)
|
|
*/
|
|
callback_t
|
|
find_callback(u_long vec)
|
|
{
|
|
struct cbhead *head;
|
|
struct callback *elm;
|
|
|
|
head = &cbhead[CBHASH(vec)];
|
|
for (elm = head->lh_first; elm; elm = elm->chain.le_next)
|
|
if (elm->vec == vec)
|
|
break;
|
|
if (elm) {
|
|
debug(D_TRAPS2, "callback %s\n", elm->name);
|
|
return (elm->func);
|
|
} else
|
|
return ((callback_t)0);
|
|
}
|
|
|
|
u_long trampoline_rover = 0xF1000000;
|
|
|
|
/*
|
|
* Interrupts are disabled on an INTn call, so we must restore interrupts
|
|
* before via STI returning. IRET is not used here because 1) some DOS
|
|
* calls want to return status via the FLAGS register, and 2) external
|
|
* routines which hook INTn calls do not always put a FLAGS image on the
|
|
* stack which re-enables interrupts.
|
|
*/
|
|
u_char softint_trampoline[] = {
|
|
0xf4, /* HLT */
|
|
0xfb, /* STI */
|
|
0xca, /* RETF 2 */
|
|
2,
|
|
0,
|
|
};
|
|
u_char hardint_trampoline[] = {
|
|
0xf4, /* HLT */
|
|
0xcf, /* IRET */
|
|
};
|
|
u_char null_trampoline[] = {
|
|
0xcf, /* IRET */
|
|
};
|
|
|
|
u_long
|
|
insert_generic_trampoline(size_t len, u_char *p)
|
|
{
|
|
u_char *q;
|
|
u_long where;
|
|
|
|
where = trampoline_rover;
|
|
q = (u_char *)VECPTR(where);
|
|
memcpy(q, p, len);
|
|
trampoline_rover += len;
|
|
return (where);
|
|
}
|
|
|
|
u_long
|
|
insert_softint_trampoline(void)
|
|
{
|
|
return (insert_generic_trampoline(
|
|
sizeof(softint_trampoline), softint_trampoline));
|
|
}
|
|
|
|
u_long
|
|
insert_hardint_trampoline(void)
|
|
{
|
|
return (insert_generic_trampoline(
|
|
sizeof(hardint_trampoline), hardint_trampoline));
|
|
}
|
|
|
|
u_long
|
|
insert_null_trampoline(void)
|
|
{
|
|
return (insert_generic_trampoline(
|
|
sizeof(null_trampoline), null_trampoline));
|
|
}
|