#include "request.h"
#include "shm.h"
#include "object.h"
#include <lib/mutex.h>
#include <mem/seg.h>
#include <mem/mem.h>
int request_get(int id, uint32_t ptr, int wait) {
int i;
//check if we own the object, if not return -2 (-10 if descriptor does not exist)
struct object *obj = objdesc_read(current_thread->process, id);
if (obj == 0) return -10;
if (obj->owner != current_thread->process) return -2;
//check if a request is pending. if request is being processed (acknowledged), return -3
if (obj->request != 0 && obj->request->acknowledged != RS_PENDING) return -3;
//if not (busymutex unlocked and request==0) && wait, then wait, else return -1
if (wait == 0 && obj->request == 0) return -1;
while (obj->busyMutex != MUTEX_LOCKED && (obj->request == 0 || obj->request->acknowledged != RS_PENDING)) thread_sleep(1);
obj->request->acknowledged = RS_PROCESSED;
//when request pending (wait finished), write it to ptr
struct user_request *p = (struct user_request*)ptr;
p->func = obj->request->func;
for (i = 0; i < 3; i++) p->params[i] = obj->request->params[i];
p->isBlocking = (obj->request->requester != 0);
//if request is nonblocking and no shm is to be mapped, delete request and unlock objects busymutex, else set it to acknowledged
if (p->isBlocking) return 0;
for (i = 0; i < 3; i++) {
if (obj->request->shm_sndr[i] != 0) return 0;
}
kfree(obj->request);
obj->request = 0;
mutex_unlock(&obj->busyMutex);
return 0;
}
int request_has(int id) {
//check if we own the object, if not return -2 (-10 if descriptor does not exist)
struct object *obj = objdesc_read(current_thread->process, id);
if (obj == 0) return -10;
if (obj->owner != current_thread->process) return -2;
//check if a request is pending.
// if none (busymutex unlocked or request==0), return 0
if (obj->request == 0 || obj->busyMutex == MUTEX_UNLOCKED) return 0;
// if waiting for ack (not acknowledged), return 1
if (obj->request->acknowledged == RS_PENDING) return 1;
// if being processed (acknowledged), return 2
return 2;
}
void request_answer(int id, uint32_t answer, uint32_t answer2) {
int i;
//check if we own the object, if not return (also return if descriptor does not exist)
struct object *obj = objdesc_read(current_thread->process, id);
if (obj == 0) return;
if (obj->owner != current_thread->process) return;
//if no blocking request is being processed (including non-acknowledged waiting requests), return
if (obj->request == 0 || obj->request->acknowledged == RS_PENDING || obj->request->requester == 0) return;
//unmap shared memory segments from shm_rcv, close descriptors to objects from obj_close
for (i = 0; i < 3; i++) {
if (obj->request->shm_rcv[i] != 0) seg_unmap(obj->request->shm_rcv[i]);
if (obj->request->obj_close[i] != 0) obj_closeP(obj->owner, obj->request->obj_close[i]);
}
//set blocking request to finished (acknowledged = 2), and set its answer
obj->request->acknowledged = RS_FINISHED;
switch (obj->request->func >> 30) {
case PT_OBJDESC:
if (obj->owner == obj->request->requester->process) {
obj->request->answer.n = answer;
} else {
int n = objdesc_get(obj->request->requester->process, objdesc_read(obj->owner, answer));
if (n == -1) {
n = objdesc_add(obj->request->requester->process, objdesc_read(obj->owner, answer));
}
obj->request->answer.n = n;
}
break;
case PT_LONG:
obj->request->answer.n = answer;
break;
case PT_LONGLONG:
obj->request->answer.ll = (uint64_t)((uint64_t)answer << 32) | answer2;
}
//wake up receiver thread (thread_wakeUp)
thread_wakeUp(obj->request->requester);
//dereference request from object, unlock objects busymutex
obj->request = 0;
mutex_unlock(&obj->busyMutex);
}
int request_mapShm(int id, uint32_t pos, int number) {
int i;
if (number > 2 || number < 0) return -9;
//check if we own the object, if not return -2 (-10 if descriptor does not exist)
struct object *obj = objdesc_read(current_thread->process, id);
if (obj == 0) return -10;
if (obj->owner != current_thread->process) return -2;
//if no request is being processes (including non-acknowledged waiting requests), return -3
if (obj->request == 0 || obj->request->acknowledged == RS_PENDING) return -3;
//check if the requests should have shm in parameter [number], if not return -4
int n = (obj->request->func >> (28 - (2 * number))) & 3;
if (n != PT_SHM) return -4;
//check if sender process is different from receiver process, if not return -7
if (obj->owner == obj->request->requester->process) return -7;
//check if sender sent a shm seg in parameter [number], if not return -5
if (obj->request->shm_sndr[number] == 0) return -5;
//map shm to position
obj->request->shm_rcv[number] = seg_map(obj->request->shm_sndr[number]->seg, obj->owner->pagedir, pos);
//if request is nonblocking and no more shm is to be mapped, delete request and free object busymutex
if (obj->request->requester != 0) return 0;
for (i = 0; i < 3; i++) {
if (obj->request->shm_sndr[i] != 0 && obj->request->shm_rcv[i] == 0) return 0;
}
kfree(obj->request);
obj->request = 0;
mutex_unlock(&obj->busyMutex);
return 0;
}
static struct request *mkrequest(int id, struct thread *requester,
uint32_t func, uint32_t a, uint32_t b, uint32_t c, uint32_t *err) {
int i;
// get object from descriptor id, if none return 0
struct object *obj = objdesc_read(current_thread->process, id);
if (obj == 0) {
*err = -10;
return 0;
}
// waitlock object's busy mutex
mutex_lock(&obj->busyMutex);
// if object cannot answer (owner == 0) return 0
if (obj->owner == 0) {
mutex_unlock(&obj->busyMutex);
*err = -11;
return 0;
}
// create request, fill it up :
struct request *rq = kmalloc(sizeof(struct request));
rq->obj = obj;
rq->requester = requester;
rq->func = func;
for (i = 0; i < 3; i++) { rq->params[i] = 0; rq->obj_close[i] = 0; rq->shm_sndr[i] = 0; rq->shm_rcv[i] = 0; }
rq->acknowledged = RS_PENDING;
// integers: use as is
// objects: open a new descriptor in receiver process (if same process, keep number), put that number as an int
// if receiver already had descriptor to this object, use it and set obj_close to 0, else set obj_close to new number
// shm: if same process, put ptr as int, else put 0 as int and get segment_map to shm_sndr
// objects and shm: 0 means sender didn't want to share anything, that should stay 0.
for (i = 0; i < 3; i++) {
int n = (rq->func >> (28 - (2 * i))) & 3;
uint32_t v = (i == 0 ? a : (i == 1 ? b : c));
switch (n) {
case PT_OBJDESC:
if (obj->owner == current_thread->process) {
rq->params[i] = v;
} else {
int d = objdesc_get(obj->owner, objdesc_read(current_thread->process, v));
if (d == -1) {
d = objdesc_add(obj->owner, objdesc_read(current_thread->process, v));
rq->obj_close[i] = d;
}
rq->params[i] = d;
}
break;
case PT_LONG:
rq->params[i] = v;
break;
case PT_SHM:
if (obj->owner == current_thread->process) {
rq->params[i] = v;
} else {
rq->shm_sndr[i] = shmseg_getByOff(current_thread->process, v);
}
break;
}
}
// reference request from object
obj->request = rq;
// return request
return rq;
}
int request(int obj, uint32_t rq_ptr) {
uint32_t e = 0;
struct user_sendrequest *urq = (void*)rq_ptr;
//call mkrequest with parameters (requester thread = current thread)
struct request *rq = mkrequest(obj, current_thread, urq->func, urq->a, urq->b, urq->c, &e);
//if returned value is 0 (could not create request), return -1
if (e != 0) return e;
if (rq == 0) return -1;
//sleep until request is handled
thread_goInactive();
//if request has been interrupted because process closed communication (acknowledged == 3), return -2
if (rq->acknowledged == 3) return -2;
//write answer to urq, delete request, return 0
switch (urq->func >> 30) {
case PT_OBJDESC:
case PT_LONG:
urq->answeri = rq->answer.n;
break;
case PT_LONGLONG:
urq->answerll = rq->answer.ll;
}
kfree(rq);
return 0;
}
int send_msg(int obj, uint32_t rq_ptr) {
uint32_t e = 0;
struct user_sendrequest *urq = (void*)rq_ptr;
//call mkrequest with parameters (requester thread = 0)
struct request *rq = mkrequest(obj, 0, urq->func, urq->a, urq->b, urq->c, &e);
//if returned value is 0, return -1 else return 0
if (e != 0) return e;
if (rq == 0) return -1;
return 0;
}
