/*
* expand the size of pipe while there is data to be read,
* and then free the old buffer once the current buffered
* data has been transferred to new storage.
* Required: PIPE_LOCK and io lock to be held by caller.
* returns 0 on success or no expansion possible
*/
static int
expand_pipespace(struct pipe *p, int target_size)
{
struct pipe tmp, oldpipe;
int error;
tmp.pipe_buffer.buffer = 0;
if (p->pipe_buffer.size >= (unsigned) target_size) {
return 0; /* the existing buffer is max size possible */
}
/* create enough space in the target */
error = pipespace(&tmp, target_size);
if (error != 0)
return (error);
oldpipe.pipe_buffer.buffer = p->pipe_buffer.buffer;
oldpipe.pipe_buffer.size = p->pipe_buffer.size;
memcpy(tmp.pipe_buffer.buffer, p->pipe_buffer.buffer, p->pipe_buffer.size);
if (p->pipe_buffer.cnt > 0 && p->pipe_buffer.in <= p->pipe_buffer.out ){
/* we are in State 3 and need extra copying for read to be consistent */
memcpy(&tmp.pipe_buffer.buffer[p->pipe_buffer.size], p->pipe_buffer.buffer, p->pipe_buffer.size);
p->pipe_buffer.in += p->pipe_buffer.size;
}
p->pipe_buffer.buffer = tmp.pipe_buffer.buffer;
p->pipe_buffer.size = tmp.pipe_buffer.size;
pipe_free_kmem(&oldpipe);
return 0;
}
/*
* Allocate kva for pipe circular buffer, the space is pageable.
* This routine will 'realloc' the size of a pipe safely, if it fails
* it will retain the old buffer.
* If it fails it will return ENOMEM.
*/
int
pipespace(struct pipe *cpipe, u_int size)
{
caddr_t buffer;
buffer = (caddr_t)uvm_km_valloc(kernel_map, size);
if (buffer == NULL) {
return (ENOMEM);
}
/* free old resources if we are resizing */
pipe_free_kmem(cpipe);
cpipe->pipe_buffer.buffer = buffer;
cpipe->pipe_buffer.size = size;
cpipe->pipe_buffer.in = 0;
cpipe->pipe_buffer.out = 0;
cpipe->pipe_buffer.cnt = 0;
amountpipekva += cpipe->pipe_buffer.size;
return (0);
}
/*
* Allocate kva for pipe circular buffer, the space is pageable.
* This routine will 'realloc' the size of a pipe safely, if it fails
* it will retain the old buffer.
* If it fails it will return ENOMEM.
*/
int
pipespace(struct pipe *cpipe, u_int size)
{
caddr_t buffer;
buffer = km_alloc(size, &kv_any, &kp_pageable, &kd_waitok);
if (buffer == NULL) {
return (ENOMEM);
}
/* free old resources if we are resizing */
pipe_free_kmem(cpipe);
cpipe->pipe_buffer.buffer = buffer;
cpipe->pipe_buffer.size = size;
cpipe->pipe_buffer.in = 0;
cpipe->pipe_buffer.out = 0;
cpipe->pipe_buffer.cnt = 0;
amountpipekva += cpipe->pipe_buffer.size;
return (0);
}
/*
* shutdown the pipe
*/
void
pipeclose(struct pipe *cpipe)
{
struct pipe *ppipe;
if (cpipe) {
pipeselwakeup(cpipe);
/*
* If the other side is blocked, wake it up saying that
* we want to close it down.
*/
cpipe->pipe_state |= PIPE_EOF;
while (cpipe->pipe_busy) {
wakeup(cpipe);
cpipe->pipe_state |= PIPE_WANT;
tsleep(cpipe, PRIBIO, "pipecl", 0);
}
/*
* Disconnect from peer
*/
if ((ppipe = cpipe->pipe_peer) != NULL) {
pipeselwakeup(ppipe);
ppipe->pipe_state |= PIPE_EOF;
wakeup(ppipe);
ppipe->pipe_peer = NULL;
}
/*
* free resources
*/
pipe_free_kmem(cpipe);
pool_put(&pipe_pool, cpipe);
}
}
/*
* Allocate kva for pipe circular buffer, the space is pageable
* This routine will 'realloc' the size of a pipe safely, if it fails
* it will retain the old buffer.
* If it fails it will return ENOMEM.
*/
static int
pipespace(struct pipe *cpipe, int size)
{
vm_offset_t buffer;
if (size <= 0)
return(EINVAL);
if ((buffer = (vm_offset_t)kalloc(size)) == 0 )
return(ENOMEM);
/* free old resources if we're resizing */
pipe_free_kmem(cpipe);
cpipe->pipe_buffer.buffer = (caddr_t)buffer;
cpipe->pipe_buffer.size = size;
cpipe->pipe_buffer.in = 0;
cpipe->pipe_buffer.out = 0;
cpipe->pipe_buffer.cnt = 0;
OSAddAtomic(1, &amountpipes);
OSAddAtomic(cpipe->pipe_buffer.size, &amountpipekva);
return (0);
}