/* $Id$
 *
 * COPYRIGHT:       See COPYING in the top level directory
 * PROJECT:         ReactOS system libraries
 * FILE:            lib/ntdll/rtl/env.c
 * PURPOSE:         Environment functions
 * PROGRAMMER:      Eric Kohl
 * UPDATE HISTORY:
 *                  Created 30/09/98
 */

/* INCLUDES ******************************************************************/

#include <ddk/ntddk.h>
#include <ntdll/rtl.h>
#include <napi/teb.h>
#include <string.h>

#define NDEBUG
#include <ntdll/ntdll.h>


/* FUNCTIONS *****************************************************************/

/*
 * @implemented
 */
NTSTATUS STDCALL
RtlCreateEnvironment(BOOLEAN Inherit,
		     PWSTR *Environment)
{
  PVOID EnvPtr = NULL;
  NTSTATUS Status = STATUS_SUCCESS;
  ULONG RegionSize = PAGE_SIZE;

  if (Inherit == TRUE)
    {
      RtlAcquirePebLock();
#if 0
      if (NtCurrentPeb()->ProcessParameters->Environment != NULL)
	{
	  Status = NtQueryVirtualMemory(NtCurrentProcess(),
					NtCurrentPeb()->ProcessParameters->Environment,
					MemoryBasicInformation,
					&MemInfo,
					sizeof(MEMORY_BASIC_INFORMATION),
					NULL);
	  if (!NT_SUCCESS(Status))
	    {
	      RtlReleasePebLock();
	      *Environment = NULL;
	      return(Status);
	    }

	  RegionSize = MemInfo.RegionSize;
	  Status = NtAllocateVirtualMemory(NtCurrentProcess(),
					   &EnvPtr,
					   0,
					   &RegionSize,
					   MEM_RESERVE | MEM_COMMIT,
					   PAGE_READWRITE);
	  if (!NT_SUCCESS(Status))
	    {
	      RtlReleasePebLock();
	      *Environment = NULL;
	      return(Status);
	    }

	  memmove(EnvPtr,
		  NtCurrentPeb ()->ProcessParameters->Environment,
		  MemInfo.RegionSize);

	  *Environment = EnvPtr;
	}
#endif
      RtlReleasePebLock ();
    }
  else
    {
      Status = NtAllocateVirtualMemory(NtCurrentProcess(),
				       &EnvPtr,
				       0,
				       &RegionSize,
				       MEM_RESERVE | MEM_COMMIT,
				       PAGE_READWRITE);
      if (NT_SUCCESS(Status))
	{
	  memset(EnvPtr,
		 0,
		 RegionSize);
	  *Environment = EnvPtr;
	}
    }

  return(Status);
}


/*
 * @implemented
 */
VOID STDCALL
RtlDestroyEnvironment(PWSTR Environment)
{
  ULONG Size = 0;

  NtFreeVirtualMemory(NtCurrentProcess(),
		      (PVOID*)&Environment,
		      &Size,
		      MEM_RELEASE);
}


/*
 * @implemented
 */
NTSTATUS STDCALL
RtlExpandEnvironmentStrings_U(PWSTR Environment,
			      PUNICODE_STRING Source,
			      PUNICODE_STRING Destination,
			      PULONG Length)
{
  UNICODE_STRING var;
  UNICODE_STRING val;
  NTSTATUS Status = STATUS_SUCCESS;
  BOOLEAN flag = FALSE;
  PWSTR s;
  PWSTR d;
  PWSTR w;
  int src_len;
  int dst_max;
  int tail;

  DPRINT("RtlExpandEnvironmentStrings_U %p %wZ %p %p\n",
	 Environment, Source, Destination, Length);

  src_len = Source->Length / sizeof(WCHAR);
  s = Source->Buffer;
  dst_max = Destination->MaximumLength / sizeof(WCHAR);
  d = Destination->Buffer;

  while (src_len)
    {
      if (*s == L'%')
	{
	  if (flag)
	    {
	      flag = FALSE;
	      goto copy;
	    }
	  w = s + 1;
	  tail = src_len - 1;
	  while (*w != L'%' && tail)
	    {
	      w++;
	      tail--;
	    }
	  if (!tail)
	    goto copy;

	  var.Length = (w - ( s + 1)) * sizeof(WCHAR);
	  var.MaximumLength = var.Length;
	  var.Buffer = s + 1;

	  val.Length = 0;
	  val.MaximumLength = dst_max * sizeof(WCHAR);
	  val.Buffer = d;
	  Status = RtlQueryEnvironmentVariable_U (Environment, &var, &val);
	  if (NT_SUCCESS(Status))
	    {
	      d += val.Length / sizeof(WCHAR);
	      dst_max -= val.Length / sizeof(WCHAR);
	      s = w + 1;
	      src_len = tail - 1;
	      continue;
	    }
	  /* variable not found or buffer too small, just copy %var% */
	  flag = TRUE;
	}
copy:
      if (!dst_max)
	{
	  Status = STATUS_BUFFER_TOO_SMALL;
	  break;
	}

      *d++ = *s++;
      dst_max--;
      src_len--;
    }

  Destination->Length = (d - Destination->Buffer) * sizeof(WCHAR);
  if (Length != NULL)
    *Length = Destination->Length;
  if (dst_max)
    Destination->Buffer[Destination->Length / sizeof(WCHAR)] = 0;

  DPRINT("Destination %wZ\n", Destination);
  return(Status);
}


/*
 * @implemented
 */
VOID STDCALL
RtlSetCurrentEnvironment(PWSTR NewEnvironment,
			 PWSTR *OldEnvironment)
{
  PVOID EnvPtr;

  DPRINT("NewEnvironment %x OldEnvironment %x\n",
	 NewEnvironment, OldEnvironment);

  RtlAcquirePebLock();

  EnvPtr = NtCurrentPeb()->ProcessParameters->Environment;
  NtCurrentPeb()->ProcessParameters->Environment = NewEnvironment;

  if (OldEnvironment != NULL)
    *OldEnvironment = EnvPtr;

  RtlReleasePebLock();
}


/*
 * @implemented
 */
NTSTATUS STDCALL
RtlSetEnvironmentVariable(PWSTR *Environment,
			  PUNICODE_STRING Name,
			  PUNICODE_STRING Value)
{
  MEMORY_BASIC_INFORMATION mbi;
  UNICODE_STRING var;
  int hole_len, new_len, env_len = 0;
  WCHAR *new_env = 0, *env_end = 0, *wcs, *env, *val = 0, *tail = 0, *hole = 0;
  PWSTR head = NULL;
  ULONG size = 0, new_size;
  LONG f = 1;
  NTSTATUS Status = STATUS_SUCCESS;

  DPRINT("RtlSetEnvironmentVariable(Environment %p Name %wZ Value %wZ)\n",
	 Environment, Name, Value);

  if (Environment)
    {
      env = *Environment;
    }
  else
    {
      RtlAcquirePebLock();
      env = NtCurrentPeb()->ProcessParameters->Environment;
    }

  if (env)
    {
      /* get environment length */
      wcs = env_end = env;
      do
      {
	 env_end += wcslen(env_end) + 1;
      }
      while (*env_end);
      env_end++;
      env_len = env_end - env;
      DPRINT("environment length %ld characters\n", env_len);

      /* find where to insert */
      while (*wcs)
	{
          var.Buffer = wcs++;
	  wcs = wcschr(wcs, L'=');
	  if (wcs == NULL)
	  {
	     wcs = var.Buffer + wcslen(var.Buffer);
	  }
	  if (*wcs)
	    {
	      var.Length = (wcs - var.Buffer) * sizeof(WCHAR);
	      var.MaximumLength = var.Length;
	      val = ++wcs;
	      wcs += wcslen(wcs); 
	      f = RtlCompareUnicodeString(&var, Name, TRUE);
	      if (f >= 0)
		{
		  if (f) /* Insert before found */
		    {
		      hole = tail = var.Buffer;
		    }
		  else /* Exact match */
		    {
		      head = var.Buffer;
		      tail = ++wcs;
		      hole = val;
		    }
		  goto found;
		}
	    }
	  wcs++;
	}
      hole = tail = wcs; /* Append to environment */
    }

found:
  if (Value->Length > 0)
    {
      hole_len = tail - hole;
      /* calculate new environment size */
      new_size = Value->Length + sizeof(WCHAR);
      /* adding new variable */
      if (f)
	new_size += Name->Length + sizeof(WCHAR);
      new_len = new_size / sizeof(WCHAR);
      if (hole_len < new_len)
	{
	  /* enlarge environment size */
	  /* check the size of available memory */
	  new_size += (env_len - hole_len) * sizeof(WCHAR);
	  new_size = ROUNDUP(new_size, PAGE_SIZE);
	  mbi.RegionSize = 0;
	  DPRINT("new_size %lu\n", new_size);

	  if (env)
	    {
	      Status = NtQueryVirtualMemory(NtCurrentProcess(),
					    env,
					    0,
					    &mbi,
					    sizeof(mbi),
					    NULL);
	      if (!NT_SUCCESS(Status))
		{
		  if (Environment == NULL)
		    {
		      RtlReleasePebLock();
		    }
		  return(Status);
		}
	    }

	  if (new_size > mbi.RegionSize)
	    {
	      /* reallocate memory area */
	      Status = NtAllocateVirtualMemory(NtCurrentProcess(),
					       (VOID**)&new_env,
					       0,
					       &new_size,
					       MEM_RESERVE | MEM_COMMIT,
					       PAGE_READWRITE);
	      if (!NT_SUCCESS(Status))
		{
		  if (Environment == NULL)
		    {
		      RtlReleasePebLock();
		    }
		  return(Status);
		}

	      if (env)
		{
		  memmove(new_env,
			  env,
			  (hole - env) * sizeof(WCHAR));
		  hole = new_env + (hole - env);
		}
	      else
		{
		  /* absolutely new environment */
		  tail = hole = new_env;
		  *hole = 0;
		  env_end = hole + 1;
		}
	    }
	}

      /* move tail */
      memmove (hole + new_len, tail, (env_end - tail) * sizeof(WCHAR));

      if (new_env)
	{
	  /* we reallocated environment, let's free the old one */
	  if (Environment)
	    *Environment = new_env;
	  else
	    NtCurrentPeb()->ProcessParameters->Environment = new_env;

	  if (env)
	    {
	      size = 0;
	      NtFreeVirtualMemory(NtCurrentProcess(),
				  (PVOID*)&env,
				  &size,
				  MEM_RELEASE);
	    }
	}

      /* and now copy given stuff */
      if (f)
	{
	  /* copy variable name and '=' character */
	  memmove(hole,
		  Name->Buffer,
		  Name->Length);
	  hole += Name->Length / sizeof(WCHAR);
	  *hole++ = L'=';
	}

      /* copy value */
      memmove(hole,
	      Value->Buffer,
	      Value->Length);
      hole += Value->Length / sizeof(WCHAR);
      *hole = 0;
    }
  else
    {
      /* remove the environment variable */
      if (f == 0)
	{
	  memmove(head,
		  tail,
		  (env_end - tail) * sizeof(WCHAR));
	}
      else
	{
	  Status = STATUS_VARIABLE_NOT_FOUND;
	}
    }

  if (Environment == NULL)
    {
      RtlReleasePebLock();
    }

  return(Status);
}


/*
 * @implemented
 */
NTSTATUS STDCALL
RtlQueryEnvironmentVariable_U(PWSTR Environment,
			      PUNICODE_STRING Name,
			      PUNICODE_STRING Value)
{
  NTSTATUS Status;
  PWSTR wcs;
  UNICODE_STRING var;
  PWSTR val;
  int len;
  BOOLEAN SysEnvUsed = FALSE;

  DPRINT("RtlQueryEnvironmentVariable_U Environment %p Variable %wZ Value %p\n",
	 Environment, Name, Value);

  if (Environment == NULL)
    {
      Environment = NtCurrentPeb()->ProcessParameters->Environment;
      SysEnvUsed = TRUE;
    }

  if (Environment == NULL)
    return(STATUS_VARIABLE_NOT_FOUND);

  Value->Length = 0;
  if (SysEnvUsed == TRUE)
    RtlAcquirePebLock();

  wcs = Environment;
  len = Name->Length / sizeof(WCHAR);
  while (*wcs)
    {
      var.Buffer = wcs++;
      wcs = wcschr(wcs, L'=');
      if (wcs == NULL)
      {
         wcs = var.Buffer + wcslen(var.Buffer);
      }
      if (*wcs)
	{
	  var.Length = var.MaximumLength = (wcs - var.Buffer) * sizeof(WCHAR);
	  val = ++wcs;
	  wcs += wcslen(wcs);

	  if (RtlEqualUnicodeString(&var, Name, TRUE))
	    {
	      Value->Length = (wcs - val) * sizeof(WCHAR);
	      if (Value->Length < Value->MaximumLength)
		{
		  memcpy(Value->Buffer, val, Value->Length + sizeof(WCHAR));
		  DPRINT("Value %S\n", val);
		  DPRINT("Return STATUS_SUCCESS\n");
		  Status = STATUS_SUCCESS;
		}
	      else
		{
		  DPRINT("Return STATUS_BUFFER_TOO_SMALL\n");
		  Status = STATUS_BUFFER_TOO_SMALL;
		}

	      if (SysEnvUsed == TRUE)
		RtlReleasePebLock();

	      return(Status);
	    }
	}
      wcs++;
    }

  if (SysEnvUsed == TRUE)
    RtlReleasePebLock();

  DPRINT("Return STATUS_VARIABLE_NOT_FOUND\n");
  return(STATUS_VARIABLE_NOT_FOUND);
}

/* EOF */