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#include <kernel/mem/virt.h>
#include <kernel/panic.h>
#include <kernel/pipe.h>
#include <kernel/util.h>
static void pipe_trytransfer(struct handle *h);
void pipe_joinqueue(struct handle *h, bool wants_write,
struct process *proc, void __user *pbuf, size_t pbuflen)
{
assert(h && h->type == HANDLE_PIPE);
if (wants_write == h->pipe.write_end) {
regs_savereturn(&proc->regs, -1);
return;
}
if (!h->pipe.sister) {
regs_savereturn(&proc->regs, -1);
return;
}
struct process **slot = &h->pipe.queued;
while (*slot) {
assert((*slot)->state == PS_WAITS4PIPE);
slot = &((*slot)->waits4pipe.next);
}
process_transition(proc, PS_WAITS4PIPE);
*slot = proc;
proc->waits4pipe.pipe = h;
proc->waits4pipe.buf = pbuf;
proc->waits4pipe.len = pbuflen;
proc->waits4pipe.next = NULL;
pipe_trytransfer(h);
}
static void pipe_trytransfer(struct handle *h) {
struct process *rdr, *wtr;
struct virt_cpy_error cpyerr;
int len;
assert(h);
if (!h->pipe.sister) {
assert(!h->pipe.queued);
return;
}
rdr = h->pipe.write_end ? h->pipe.sister->pipe.queued : h->pipe.queued;
wtr = h->pipe.write_end ? h->pipe.queued : h->pipe.sister->pipe.queued;
if (!(rdr && wtr)) return;
assert(rdr->state == PS_WAITS4PIPE);
assert(wtr->state == PS_WAITS4PIPE);
len = min(rdr->waits4pipe.len, wtr->waits4pipe.len);
virt_cpy(
rdr->pages, rdr->waits4pipe.buf,
wtr->pages, wtr->waits4pipe.buf,
len, &cpyerr);
if (cpyerr.read_fail || cpyerr.write_fail)
panic_unimplemented();
h->pipe.queued = h->pipe.queued->waits4pipe.next;
h->pipe.sister->pipe.queued = h->pipe.sister->pipe.queued->waits4pipe.next;
process_transition(rdr, PS_RUNNING);
process_transition(wtr, PS_RUNNING);
regs_savereturn(&rdr->regs, len);
regs_savereturn(&wtr->regs, len);
}
void pipe_invalidate_end(struct handle *h) {
struct process *p = h->pipe.queued;
while (p) {
assert(p->state == PS_WAITS4PIPE);
process_transition(p, PS_RUNNING);
regs_savereturn(&p->regs, -1);
p = p->waits4pipe.next;
}
h->pipe.queued = NULL;
}
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