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Differential D20784 Diff 59199 head/sys/kern/sys_pipe.c

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head/sys/kern/sys_pipe.c

Show First 20 Lines • Show All 718 Lines • ▼ Show 20 Lines */
rpipe->pipe_map.pos, size, uio); rpipe->pipe_map.pos, size, uio);
PIPE_LOCK(rpipe); PIPE_LOCK(rpipe);
if (error) if (error)
break; break;
nread += size; nread += size;
rpipe->pipe_map.pos += size; rpipe->pipe_map.pos += size;
rpipe->pipe_map.cnt -= size; rpipe->pipe_map.cnt -= size;
if (rpipe->pipe_map.cnt == 0) { if (rpipe->pipe_map.cnt == 0) {
rpipe->pipe_state &= ~(PIPE_DIRECTW|PIPE_WANTW); rpipe->pipe_state &= ~PIPE_WANTW;
wakeup(rpipe); wakeup(rpipe);
} }
#endif #endif
} else { } else {
/* /*
* detect EOF condition * detect EOF condition
* read returns 0 on EOF, no need to set error * read returns 0 on EOF, no need to set error
*/ */
▲ Show 20 Lines • Show All 114 Lines • ▼ Show 20 Lines */
if (uio->uio_iov->iov_len == 0) if (uio->uio_iov->iov_len == 0)
uio->uio_iov++; uio->uio_iov++;
uio->uio_resid -= size; uio->uio_resid -= size;
uio->uio_offset += size; uio->uio_offset += size;
return (0); return (0);
} }
/* /*
* unmap and unwire the process buffer * Unwire the process buffer.
*/ */
static void static void
pipe_destroy_write_buffer(struct pipe *wpipe) pipe_destroy_write_buffer(struct pipe *wpipe)
{ {
PIPE_LOCK_ASSERT(wpipe, MA_OWNED); PIPE_LOCK_ASSERT(wpipe, MA_OWNED);
KASSERT((wpipe->pipe_state & PIPE_DIRECTW) != 0,
("%s: PIPE_DIRECTW not set on %p", __func__, wpipe));
wpipe->pipe_state &= ~PIPE_DIRECTW;
vm_page_unhold_pages(wpipe->pipe_map.ms, wpipe->pipe_map.npages); vm_page_unhold_pages(wpipe->pipe_map.ms, wpipe->pipe_map.npages);
wpipe->pipe_map.npages = 0; wpipe->pipe_map.npages = 0;
} }
/* /*
* In the case of a signal, the writing process might go away. This * In the case of a signal, the writing process might go away. This
* code copies the data into the circular buffer so that the source * code copies the data into the circular buffer so that the source
* pages can be freed without loss of data. * pages can be freed without loss of data.
*/ */
static void static void
pipe_clone_write_buffer(struct pipe *wpipe) pipe_clone_write_buffer(struct pipe *wpipe)
{ {
struct uio uio; struct uio uio;
struct iovec iov; struct iovec iov;
int size; int size;
int pos; int pos;
PIPE_LOCK_ASSERT(wpipe, MA_OWNED); PIPE_LOCK_ASSERT(wpipe, MA_OWNED);
KASSERT((wpipe->pipe_state & PIPE_DIRECTW) != 0,
("%s: PIPE_DIRECTW not set on %p", __func__, wpipe));
size = wpipe->pipe_map.cnt; size = wpipe->pipe_map.cnt;
pos = wpipe->pipe_map.pos; pos = wpipe->pipe_map.pos;
wpipe->pipe_buffer.in = size; wpipe->pipe_buffer.in = size;
wpipe->pipe_buffer.out = 0; wpipe->pipe_buffer.out = 0;
wpipe->pipe_buffer.cnt = size; wpipe->pipe_buffer.cnt = size;
wpipe->pipe_state &= ~PIPE_DIRECTW;
PIPE_UNLOCK(wpipe); PIPE_UNLOCK(wpipe);
iov.iov_base = wpipe->pipe_buffer.buffer; iov.iov_base = wpipe->pipe_buffer.buffer;
iov.iov_len = size; iov.iov_len = size;
uio.uio_iov = &iov; uio.uio_iov = &iov;
uio.uio_iovcnt = 1; uio.uio_iovcnt = 1;
uio.uio_offset = 0; uio.uio_offset = 0;
uio.uio_resid = size; uio.uio_resid = size;
Show All 22 Linesretry:
error = pipelock(wpipe, 1); error = pipelock(wpipe, 1);
if (error != 0) if (error != 0)
goto error1; goto error1;
if ((wpipe->pipe_state & PIPE_EOF) != 0) { if ((wpipe->pipe_state & PIPE_EOF) != 0) {
error = EPIPE; error = EPIPE;
pipeunlock(wpipe); pipeunlock(wpipe);
goto error1; goto error1;
} }
while (wpipe->pipe_state & PIPE_DIRECTW) { if (wpipe->pipe_state & PIPE_DIRECTW) {
if (wpipe->pipe_state & PIPE_WANTR) { if (wpipe->pipe_state & PIPE_WANTR) {
wpipe->pipe_state &= ~PIPE_WANTR; wpipe->pipe_state &= ~PIPE_WANTR;
wakeup(wpipe); wakeup(wpipe);
} }
pipeselwakeup(wpipe); pipeselwakeup(wpipe);
wpipe->pipe_state |= PIPE_WANTW; wpipe->pipe_state |= PIPE_WANTW;
pipeunlock(wpipe); pipeunlock(wpipe);
error = msleep(wpipe, PIPE_MTX(wpipe), error = msleep(wpipe, PIPE_MTX(wpipe),
Show All 26 Linesretry:
error = pipe_build_write_buffer(wpipe, uio); error = pipe_build_write_buffer(wpipe, uio);
PIPE_LOCK(wpipe); PIPE_LOCK(wpipe);
if (error) { if (error) {
wpipe->pipe_state &= ~PIPE_DIRECTW; wpipe->pipe_state &= ~PIPE_DIRECTW;
pipeunlock(wpipe); pipeunlock(wpipe);
goto error1; goto error1;
} }
error = 0; while (wpipe->pipe_map.cnt != 0) {
while (!error && (wpipe->pipe_state & PIPE_DIRECTW)) {
if (wpipe->pipe_state & PIPE_EOF) { if (wpipe->pipe_state & PIPE_EOF) {
pipe_destroy_write_buffer(wpipe); pipe_destroy_write_buffer(wpipe);
pipeselwakeup(wpipe); pipeselwakeup(wpipe);
pipeunlock(wpipe); pipeunlock(wpipe);
error = EPIPE; error = EPIPE;
goto error1; goto error1;
} }
if (wpipe->pipe_state & PIPE_WANTR) { if (wpipe->pipe_state & PIPE_WANTR) {
wpipe->pipe_state &= ~PIPE_WANTR; wpipe->pipe_state &= ~PIPE_WANTR;
wakeup(wpipe); wakeup(wpipe);
} }
pipeselwakeup(wpipe); pipeselwakeup(wpipe);
wpipe->pipe_state |= PIPE_WANTW; wpipe->pipe_state |= PIPE_WANTW;
pipeunlock(wpipe); pipeunlock(wpipe);
error = msleep(wpipe, PIPE_MTX(wpipe), PRIBIO | PCATCH, error = msleep(wpipe, PIPE_MTX(wpipe), PRIBIO | PCATCH,
"pipdwt", 0); "pipdwt", 0);
pipelock(wpipe, 0); pipelock(wpipe, 0);
if (error != 0)
break;
} }
if (wpipe->pipe_state & PIPE_EOF) if (wpipe->pipe_state & PIPE_EOF)
error = EPIPE; error = EPIPE;
if (wpipe->pipe_state & PIPE_DIRECTW) { if (error == EINTR || error == ERESTART)
/*
* this bit of trickery substitutes a kernel buffer for
* the process that might be going away.
*/
pipe_clone_write_buffer(wpipe); pipe_clone_write_buffer(wpipe);
} else { else
pipe_destroy_write_buffer(wpipe); pipe_destroy_write_buffer(wpipe);
}
pipeunlock(wpipe); pipeunlock(wpipe);
KASSERT((wpipe->pipe_state & PIPE_DIRECTW) == 0,
("pipe %p leaked PIPE_DIRECTW", wpipe));
return (error); return (error);
error1: error1:
wakeup(wpipe); wakeup(wpipe);
return (error); return (error);
} }
#endif #endif
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