minix/lib/libsys/asynsend.c

139 lines
2.6 KiB
C

#define _MINIX 1
#define _SYSTEM 1
#include <minix/config.h>
#include <ansi.h>
#include <assert.h>
#include <sys/types.h>
#include <minix/const.h>
#include <minix/type.h>
#include <stdlib.h>
#include <unistd.h>
#include <minix/syslib.h>
#include <minix/sysutil.h>
#include <limits.h>
#include <errno.h>
#define ASYN_NR 100
PRIVATE asynmsg_t msgtable[ASYN_NR];
PRIVATE int first_slot= 0, next_slot= 0;
PUBLIC int asynsend3(dst, mp, fl)
endpoint_t dst;
message *mp;
int fl;
{
int r, src_ind, dst_ind;
unsigned flags;
static int first = 1;
static int inside = 0;
int len;
/* printf() causes asynsend? */
if(inside) {
exit(1);
}
inside = 1;
if(first) {
int i;
for(i = 0; i < ASYN_NR; i++) {
msgtable[i].flags = AMF_EMPTY;
}
first = 0;
}
/* Update first_slot */
for (; first_slot < next_slot; first_slot++)
{
flags= msgtable[first_slot].flags;
if ((flags & (AMF_VALID|AMF_DONE)) == (AMF_VALID|AMF_DONE))
{
if (msgtable[first_slot].result != OK)
{
#if 0
printf(
"asynsend: found completed entry %d with error %d\n",
first_slot,
msgtable[first_slot].result);
#endif
}
continue;
}
if (flags != AMF_EMPTY)
break;
}
if (first_slot >= next_slot)
{
/* Reset first_slot and next_slot */
next_slot= first_slot= 0;
}
if (next_slot >= ASYN_NR)
{
/* Tell the kernel to stop processing */
r= senda(NULL, 0);
if (r != OK)
panic(__FILE__, "asynsend: senda failed", r);
dst_ind= 0;
for (src_ind= first_slot; src_ind<next_slot; src_ind++)
{
flags= msgtable[src_ind].flags;
if ((flags & (AMF_VALID|AMF_DONE)) ==
(AMF_VALID|AMF_DONE))
{
if (msgtable[src_ind].result != OK)
{
#if 0
printf(
"asynsend: found completed entry %d with error %d\n",
src_ind,
msgtable[src_ind].result);
#endif
}
continue;
}
if (flags == AMF_EMPTY)
continue;
#if 0
printf("asynsend: copying entry %d to %d\n",
src_ind, dst_ind);
#endif
if (src_ind != dst_ind)
msgtable[dst_ind]= msgtable[src_ind];
dst_ind++;
}
first_slot= 0;
next_slot= dst_ind;
if (next_slot >= ASYN_NR)
panic(__FILE__, "asynsend: msgtable full", NO_NUM);
}
fl |= AMF_VALID;
msgtable[next_slot].dst= dst;
msgtable[next_slot].msg= *mp;
msgtable[next_slot].flags= fl; /* Has to be last. The kernel
* scans this table while we
* are sleeping.
*/
next_slot++;
assert(first_slot < ASYN_NR);
assert(next_slot >= first_slot);
len = next_slot-first_slot;
assert(first_slot + len <= ASYN_NR);
/* Tell the kernel to rescan the table */
r = senda(msgtable+first_slot, len);
inside = 0;
return r;
}