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/* PTYFS slave node management */
/*
* While the interface of this module should be flexible enough to implement
* various memory management approaches, the current code simply relies on
* NR_PTYS being small enough to preallocate all data structures. In the
* future, NR_PTYS will no longer be a system-global definition, and future
* implementations of this module should not rely on NR_PTYS at all.
*/
#include <minix/drivers.h>
#include "node.h"
static bitchunk_t node_map[BITMAP_CHUNKS(NR_PTYS)];
static struct node_data node_data[NR_PTYS];
/*
* Initialize the node module.
*/
void
init_nodes(void)
{
memset(&node_map, 0, sizeof(node_map));
}
/*
* Allocate a node with a given node index number, and save node data for it.
* It is possible that the node is in use already; in that case, only update
* its associated data. Return OK on success, or an error code on failure.
*/
int
set_node(node_t index, struct node_data * data)
{
if (index >= NR_PTYS)
return ENOMEM;
SET_BIT(node_map, index);
node_data[index] = *data;
return OK;
}
/*
* Deallocate a node using its node index number. This function always
* succeeds, intentionally ignoring the case that the node was not allocated.
*/
void
clear_node(node_t index)
{
UNSET_BIT(node_map, index);
}
/*
* Return a pointer to the node data associated with the given node index
* number. If the node is not allocated, return NULL.
*/
struct node_data *
get_node(node_t index)
{
if (index >= NR_PTYS || !GET_BIT(node_map, index))
return NULL;
return &node_data[index];
}
/*
* Return the highest allocated node index number, plus one. This value is
* used to check given node indices and limit linear iterations.
*/
node_t
get_max_node(void)
{
/*
* NR_PTYS is low enough that we can always return it instead of
* tracking the actual value.
*/
return NR_PTYS;
}
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