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#include <kernel/mem/virt.h>
#include <kernel/panic.h>
#include <kernel/pipe.h>
#include <kernel/util.h>
void pipe_joinqueue(struct handle *h, bool wants_write,
struct process *proc, void __user *pbuf, size_t pbuflen)
{
struct process **slot = wants_write ? &h->pipe.reader : &h->pipe.writer;
if (*slot) {
assert((*slot)->state == PS_WAITS4PIPE);
panic_unimplemented();
}
process_transition(proc, PS_WAITS4PIPE);
*slot = proc;
proc->waits4pipe.pipe = h;
proc->waits4pipe.buf = pbuf;
proc->waits4pipe.len = pbuflen;
}
void pipe_trytransfer(struct handle *h) {
struct process *rdr = h->pipe.reader, *wtr = h->pipe.writer;
int len;
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.reader = NULL;
h->pipe.writer = NULL;
regs_savereturn(&rdr->regs, len);
regs_savereturn(&wtr->regs, len);
}
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