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