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#include <kernel/mem/virt.h>
#include <kernel/panic.h>
#include <kernel/pipe.h>
#include <kernel/util.h>
bool 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) return false;
if (!h->pipe.sister) return false;
if (h->pipe.queued) {
assert(h->pipe.queued->state == PS_WAITS4PIPE);
panic_unimplemented();
}
process_transition(proc, PS_WAITS4PIPE);
h->pipe.queued = proc;
proc->waits4pipe.pipe = h;
proc->waits4pipe.buf = pbuf;
proc->waits4pipe.len = pbuflen;
return true;
}
void pipe_trytransfer(struct handle *h) {
struct process *rdr, *wtr;
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);
if (!virt_cpy(
rdr->pages, rdr->waits4pipe.buf,
wtr->pages, wtr->waits4pipe.buf, len))
{
panic_unimplemented();
}
process_transition(rdr, PS_RUNNING);
process_transition(wtr, PS_RUNNING);
h->pipe.queued = NULL;
h->pipe.sister->pipe.queued = NULL;
regs_savereturn(&rdr->regs, len);
regs_savereturn(&wtr->regs, len);
}
void pipe_invalidate_end(struct handle *h) {
struct process *p = h->pipe.queued;
if (p) {
process_transition(p, PS_RUNNING);
regs_savereturn(&p->regs, -1);
}
h->pipe.queued = NULL;
}
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