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test for closed pipe or killed on every char, not just if pipe full

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Robert Morris 2020-10-22 06:36:36 -04:00 committed by Frans Kaashoek
parent 329935eca8
commit e1bb4c7434
1 changed files with 14 additions and 11 deletions
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25
kernel/pipe.c
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@ -76,26 +76,29 @@ pipeclose(struct pipe *pi, int writable)
int
pipewrite(struct pipe *pi, uint64 addr, int n)
{
int i;
char ch;
int i = 0;
struct proc *pr = myproc();
acquire(&pi->lock);
for(i = 0; i < n; i++){
while(pi->nwrite == pi->nread + PIPESIZE){ //DOC: pipewrite-full
if(pi->readopen == 0 || pr->killed){
release(&pi->lock);
return -1;
}
while(i < n){
if(pi->readopen == 0 || pr->killed){
release(&pi->lock);
return -1;
}
if(pi->nwrite == pi->nread + PIPESIZE){ //DOC: pipewrite-full
wakeup(&pi->nread);
sleep(&pi->nwrite, &pi->lock);
} else {
char ch;
if(copyin(pr->pagetable, &ch, addr + i, 1) == -1)
break;
pi->data[pi->nwrite++ % PIPESIZE] = ch;
i++;
}
if(copyin(pr->pagetable, &ch, addr + i, 1) == -1)
break;
pi->data[pi->nwrite++ % PIPESIZE] = ch;
}
wakeup(&pi->nread);
release(&pi->lock);
return i;
}