NTSTATUS NTAPI RtlSetEnvironmentVariable	(	PWSTR *	Environment,
		PUNICODE_STRING	Name,
		PUNICODE_STRING	Value
	)
Definition at line 268 of file env.c.
Referenced by AppendUserEnvironmentVariable(), SetEnvironmentVariableA(), SetEnvironmentVariableW(), SetUserEnvironmentVariable(), and SmpConfigureEnvironment().
{
   MEMORY_BASIC_INFORMATION mbi;
   UNICODE_STRING var;
   size_t 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;
   SIZE_T size = 0, new_size;
   LONG f = 1;
   NTSTATUS Status = STATUS_SUCCESS;

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

   /* Variable name must not be empty */
   if (Name->Length < sizeof(WCHAR))
      return STATUS_INVALID_PARAMETER;

   /* Variable names can't contain a '=' except as a first character. */
   for (wcs = Name->Buffer + 1;
        wcs < Name->Buffer + (Name->Length / sizeof(WCHAR));
        wcs++)
   {
      if (*wcs == L'=')
          return STATUS_INVALID_PARAMETER;
   }

   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 = (USHORT)(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 != NULL && Value->Buffer != NULL)
   {
      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 = ROUND_UP(new_size, PAGE_SIZE);
         mbi.RegionSize = 0;
         DPRINT("new_size %lu\n", new_size);

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

         if (new_size > mbi.RegionSize)
         {
            /* reallocate memory area */
            Status = NtAllocateVirtualMemory(NtCurrentProcess(),
                                             (PVOID)&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));
      }
   }

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

   return(Status);
}
ReactOS Development > Doxygen
