entered advanced internal development stage.

1 files changed, 112 insertions, 0 deletions

diff --git a/src/argv/ntapi_tt_env_vars.c b/src/argv/ntapi_tt_env_vars.c
new file mode 100644
index 0000000..1af9b77
--- /dev/null
+++ b/src/argv/ntapi_tt_env_vars.c
@@ -0,0 +1,112 @@
+/********************************************************/
+/*  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;
+}
+