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#include <minix/config.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 <minix/sys_config.h>
#include <limits.h>
#include <errno.h>
#define ASYN_NR (2*_NR_PROCS)
static asynmsg_t msgtable[ASYN_NR];
static int first_slot = 0, next_slot = 0;
static int initialized = 0;
/*===========================================================================*
* asynsend3 *
*===========================================================================*/
int asynsend3(dst, mp, fl)
endpoint_t dst;
message *mp;
int fl;
{
int i, r, src_ind, dst_ind;
unsigned flags;
static int inside = 0;
int needack = 0;
/* Debug printf() causes asynchronous sends? */
if (inside) /* Panic will not work either then, so exit */
exit(1);
inside = 1;
if(!initialized) {
/* Initialize table by marking all entries empty */
for (i = 0; i < ASYN_NR; i++) msgtable[i].flags = AMF_EMPTY;
initialized = 1;
}
/* Update first_slot. That is, find the first not-completed slot by the
* kernel since the last time we sent this table (e.g., the receiving end of
* the message wasn't ready yet).
*/
for (; first_slot < next_slot; first_slot++) {
flags = msgtable[first_slot].flags;
if ((flags & (AMF_VALID|AMF_DONE)) == (AMF_VALID|AMF_DONE)) {
/* Marked in use by us (VALID) and processed by the kernel */
if (msgtable[first_slot].result != OK) {
#ifdef DEBUG
printf("asynsend: found entry %d with error %d\n",
first_slot, msgtable[first_slot].result);
#endif
needack = (flags & (AMF_NOTIFY|AMF_NOTIFY_ERR));
}
continue;
}
if (flags != AMF_EMPTY)
/* Found first not-completed table entry */
break;
}
/* Reset to the beginning of the table when all messages are completed */
if (first_slot >= next_slot && !needack)
next_slot = first_slot = 0;
/* Can the table handle one more message? */
if (next_slot >= ASYN_NR) {
/* We're full; tell the kernel to stop processing for now */
if ((r = ipc_senda(NULL, 0)) != OK)
panic("asynsend: ipc_senda failed: %d", r);
/* Move all unprocessed messages to the beginning */
dst_ind = 0;
for (src_ind = first_slot; src_ind < next_slot; src_ind++) {
flags = msgtable[src_ind].flags;
/* Skip empty entries */
if (flags == AMF_EMPTY) continue;
/* and completed entries only if result is OK or if error
* doesn't need to be acknowledged */
if ((flags & (AMF_VALID|AMF_DONE)) == (AMF_VALID|AMF_DONE)) {
if (msgtable[src_ind].result == OK)
continue;
else {
#ifdef DEBUG
printf(
"asynsend: found entry %d with error %d\n",
src_ind, msgtable[src_ind].result);
#endif
if (!(flags & (AMF_NOTIFY|AMF_NOTIFY_ERR)))
/* Don't need to ack this error */
continue;
}
}
/* Copy/move in use entry */
#ifdef DEBUG
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++;
}
/* Mark unused entries empty */
for (i = dst_ind; i < ASYN_NR; i++) msgtable[i].flags = AMF_EMPTY;
first_slot = 0;
next_slot = dst_ind;
if (next_slot >= ASYN_NR) /* Cleanup failed */
panic("asynsend: msgtable full");
}
fl |= AMF_VALID; /* Mark in use */
msgtable[next_slot].dst = dst;
msgtable[next_slot].msg = *mp;
__insn_barrier();
msgtable[next_slot].flags = fl; /* Has to be last. The kernel
* scans this table while we
* are sleeping.
*/
next_slot++;
/* Reload. */
inside = 0;
r = senda_reload();
return r;
}
/*===========================================================================*
* senda_reload *
*===========================================================================*/
int senda_reload()
{
int len;
assert(next_slot >= first_slot);
len = next_slot - first_slot;
assert(first_slot + len <= ASYN_NR);
assert(len >= 0);
/* Tell the kernel to rescan the table */
return ipc_senda(&msgtable[first_slot], len);
}
/*===========================================================================*
* asyn_geterror *
*===========================================================================*/
int asyn_geterror(endpoint_t *dst, message *msg, int *err)
{
int src_ind, flags, result;
if (!initialized) return(0);
for (src_ind = 0; src_ind < next_slot; src_ind++) {
flags = msgtable[src_ind].flags;
result = msgtable[src_ind].result;
/* Find a message that has been completed with an error */
if ((flags & (AMF_VALID|AMF_DONE)) == (AMF_VALID|AMF_DONE)) {
if (result != OK && (flags & (AMF_NOTIFY|AMF_NOTIFY_ERR))) {
/* Found one */
if (dst != NULL) *dst = msgtable[src_ind].dst;
if (msg != NULL) *msg = msgtable[src_ind].msg;
if (err != NULL) *err = result;
/* Acknowledge error so it can be cleaned up upon next
* asynsend */
msgtable[src_ind].result = OK;
return(1);
}
}
}
return(0);
}
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