Blame src/internal/ptycon_memfn_impl.c

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/*********************************************************/
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/*  ptycon: a pty-console bridge                         */
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/*  Copyright (C) 2016  Z. Gilboa                        */
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/*  Released under GPLv2 and GPLv3; see COPYING.PTYCON.  */
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/*********************************************************/
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#include <stddef.h>
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#include <ntapi/ntapi.h>
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#include "ptycon_memfn_impl.h"
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#include "ptycon_driver_impl.h"
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void * ptyc_calloc(size_t n, size_t size)
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{
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	struct ptyc_memory_block block;
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	if (!n || (size > (size_t)(-1) / n))
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		return 0;
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	size *= n;
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	size += 0xf;
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	size &= ~(size_t)0xf;
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	block.addr = 0;
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	block.size = size + sizeof(block);
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	if (ntapi->zw_allocate_virtual_memory(
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			NT_CURRENT_PROCESS_HANDLE,
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			&block.addr,
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			0,
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			&block.size,
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			NT_MEM_COMMIT,
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			NT_PAGE_READWRITE))
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		return 0;
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	block.used  = size;
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	block.avail = block.size - block.used;
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	return (char *)block.addr + offsetof(struct ptyc_memory_block,buffer);
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}
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void * ptyc_balloc(
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	struct ptyc_memory_block * cache,
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	struct ptyc_memory_block * block,
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	size_t n, size_t size)
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{
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	char * baddr;
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	void * addr = 0;
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	if (!n || (size > (size_t)(-1) / n))
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		return 0;
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	if (!cache || !cache->addr)
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		addr = ptyc_calloc(n,size);
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	size *= n;
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	size += 0xf;
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	size &= ~(size_t)0xf;
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	if (size < block->avail)
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		addr = ptyc_calloc(n,size);
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	/* newly allocated block? */
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	if (addr) {
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		baddr  = addr;
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		baddr -= offsetof(struct ptyc_memory_block,buffer);
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		ntapi->tt_aligned_block_memcpy(
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			(uintptr_t *)block,
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			(uintptr_t *)baddr,
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			sizeof(*block));
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		return addr;
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	}
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	/* cache */
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	addr = &block->buffer[block->used / sizeof(size_t)];
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	block->used  += size;
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	block->avail -= size;
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	return addr;
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}
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void ptyc_free(void * addr)
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{
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	struct ptyc_memory_block block;
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	block.addr = addr;
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	block.size = 0;
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	ntapi->zw_free_virtual_memory(
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		NT_CURRENT_PROCESS_HANDLE,
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		&block.addr,
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		&block.size,
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		NT_MEM_RELEASE);
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}