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/********************************************************/
/* ntapi: Native API core library */
/* Copyright (C) 2013,2014,2015 Z. Gilboa */
/* Released under GPLv2 and GPLv3; see COPYING.NTAPI. */
/********************************************************/
#include <psxtypes/psxtypes.h>
#include <ntapi/ntapi.h>
#include "ntapi_impl.h"
int32_t __stdcall __ntapi_tt_get_env_var_meta_utf16(
__in const uint32_t * crc32_table,
__in wchar16_t * env_var_name,
__in uint32_t env_var_name_hash __optional,
__in wchar16_t ** envp,
__out nt_env_var_meta_utf16 * env_var_meta)
{
int idx;
uint32_t crc32;
unsigned char * byte_buffer;
wchar16_t * wch;
#define EQUAL_SIGN 0x3D
/* step 1: crc32 of the target env_var_name */
if (env_var_name_hash)
crc32 = env_var_name_hash;
else {
crc32 = 0 ^ 0xFFFFFFFF;
/* initialize byte_buffer */
byte_buffer = (unsigned char *)env_var_name;
/* iterate */
while (*byte_buffer) {
/* two bytes at a time */
crc32 = (crc32 >> 8) ^ crc32_table[(crc32 ^ *byte_buffer) & 0xFF];
byte_buffer++;
crc32 = (crc32 >> 8) ^ crc32_table[(crc32 ^ *byte_buffer) & 0xFF];
byte_buffer++;
}
crc32 = (crc32 ^ 0xFFFFFFFF);
}
/* initialize the env_var_meta structure */
env_var_meta->name_hash = crc32;
env_var_meta->name = (wchar16_t *)0;
env_var_meta->value = (wchar16_t *)0;
env_var_meta->value_hash = 0;
env_var_meta->envp_index = 0;
env_var_meta->flags = 0;
/* step 2: look for the environment variable in envp[] */
idx = 0;
while (envp[idx] && (!env_var_meta->value)) {
wch = envp[idx];
/* find the equal sign */
while ((*wch) && (*wch != EQUAL_SIGN))
wch++;
if (*wch != EQUAL_SIGN)
return NT_STATUS_ILLEGAL_CHARACTER;
/* hash the current environment variable */
crc32 = 0 ^ 0xFFFFFFFF;
/* initialize byte_buffer */
byte_buffer = (unsigned char *)envp[idx];
/* iterate */
while ((uintptr_t)(byte_buffer) < (uintptr_t)wch) {
/* two bytes at a time */
crc32 = (crc32 >> 8) ^ crc32_table[(crc32 ^ *byte_buffer) & 0xFF];
byte_buffer++;
crc32 = (crc32 >> 8) ^ crc32_table[(crc32 ^ *byte_buffer) & 0xFF];
byte_buffer++;
}
if (env_var_meta->name_hash == (crc32 ^ 0xFFFFFFFF)) {
/* found it, get ready to hash the value */
wch++;
env_var_meta->name = envp[idx];
env_var_meta->value = wch;
env_var_meta->envp_index = idx;
} else {
idx++;
}
}
if (env_var_meta->value) {
/* hash the value: utf-16, null-terminated */
crc32 = 0 ^ 0xFFFFFFFF;
/* initialize byte_buffer */
byte_buffer = (unsigned char *)env_var_meta->value;
/* iterate */
while (*byte_buffer) {
/* two bytes at a time */
crc32 = (crc32 >> 8) ^ crc32_table[(crc32 ^ *byte_buffer) & 0xFF];
byte_buffer++;
crc32 = (crc32 >> 8) ^ crc32_table[(crc32 ^ *byte_buffer) & 0xFF];
byte_buffer++;
}
env_var_meta->value_hash = (crc32 ^ 0xFFFFFFFF);
}
return NT_STATUS_SUCCESS;
}
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