[System.Security.SecurityCritical] // auto-generated
private unsafe static string NormalizePath(string path, bool fullCheck, int maxPathLength, bool expandShortPaths)
{
Contract.Requires(path != null, "path can't be null");
// If the path is in extended syntax, we don't need to normalize, but we still do some basic validity checks
if (PathInternal.IsExtended(path))
{
if (!ValidateExtendedPath(path, fullCheck))
{
throw new ArgumentException(SR.Arg_PathIllegal);
}
// \\?\GLOBALROOT gives access to devices out of the scope of the current user, we
// don't want to allow this for security reasons.
// https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247.aspx#nt_namespaces
if (path.StartsWith(@"\\?\globalroot", StringComparison.OrdinalIgnoreCase))
throw new ArgumentException(SR.Arg_PathGlobalRoot);
return path;
}
// If we're doing a full path check, trim whitespace and look for
// illegal path characters.
if (fullCheck)
{
// Trim whitespace off the end of the string.
// Win32 normalization trims only U+0020.
path = path.TrimEnd(TrimEndChars);
// Look for illegal path characters.
PathInternal.CheckInvalidPathChars(path);
}
int index = 0;
// We prefer to allocate on the stack for workingset/perf gain. If the
// starting path is less than MaxPath then we can stackalloc; otherwise we'll
// use a StringBuilder (PathHelper does this under the hood). The latter may
// happen in 2 cases:
// 1. Starting path is greater than MaxPath but it normalizes down to MaxPath.
// This is relevant for paths containing escape sequences. In this case, we
// attempt to normalize down to MaxPath, but the caller pays a perf penalty
// since StringBuilder is used.
// 2. IsolatedStorage, which supports paths longer than MaxPath (value given
// by maxPathLength.
PathHelper newBuffer = new PathHelper(path.Length + MaxPath, maxPathLength);
uint numSpaces = 0;
uint numDots = 0;
bool fixupDirectorySeparator = false;
// Number of significant chars other than potentially suppressible
// dots and spaces since the last directory or volume separator char
uint numSigChars = 0;
int lastSigChar = -1; // Index of last significant character.
// Whether this segment of the path (not the complete path) started
// with a volume separator char. Reject "c:...".
bool startedWithVolumeSeparator = false;
bool firstSegment = true;
int lastDirectorySeparatorPos = 0;
bool mightBeShortFileName = false;
// LEGACY: This code is here for backwards compatibility reasons. It
// ensures that \\foo.cs\bar.cs stays \\foo.cs\bar.cs instead of being
// turned into \foo.cs\bar.cs.
if (path.Length > 0 && PathInternal.IsDirectorySeparator(path[0]))
{
newBuffer.Append('\\');
index++;
lastSigChar = 0;
}
// Normalize the string, stripping out redundant dots, spaces, and
// slashes.
while (index < path.Length)
{
char currentChar = path[index];
// We handle both directory separators and dots specially. For
// directory separators, we consume consecutive appearances.
// For dots, we consume all dots beyond the second in
// succession. All other characters are added as is. In
// addition we consume all spaces after the last other char
// in a directory name up until the directory separator.
if (PathInternal.IsDirectorySeparator(currentChar))
{
// If we have a path like "123.../foo", remove the trailing dots.
// However, if we found "c:\temp\..\bar" or "c:\temp\...\bar", don't.
// Also remove trailing spaces from both files & directory names.
// This was agreed on with the OS team to fix undeletable directory
// names ending in spaces.
// If we saw a '\' as the previous last significant character and
// are simply going to write out dots, suppress them.
// If we only contain dots and slashes though, only allow
// a string like [dot]+ [space]*. Ignore everything else.
// Legal: "\.. \", "\...\", "\. \"
// Illegal: "\.. .\", "\. .\", "\ .\"
if (numSigChars == 0)
{
// Dot and space handling
if (numDots > 0)
{
// Look for ".[space]*" or "..[space]*"
int start = lastSigChar + 1;
if (path[start] != '.')
throw new ArgumentException(SR.Arg_PathIllegal);
// Only allow "[dot]+[space]*", and normalize the
// legal ones to "." or ".."
if (numDots >= 2)
{
// Reject "C:..."
if (startedWithVolumeSeparator && numDots > 2)
throw new ArgumentException(SR.Arg_PathIllegal);
if (path[start + 1] == '.')
{
// Search for a space in the middle of the
// dots and throw
for (int i = start + 2; i < start + numDots; i++)
{
if (path[i] != '.')
throw new ArgumentException(SR.Arg_PathIllegal);
}
numDots = 2;
}
else
{
if (numDots > 1)
throw new ArgumentException(SR.Arg_PathIllegal);
numDots = 1;
}
}
if (numDots == 2)
{
newBuffer.Append('.');
}
newBuffer.Append('.');
fixupDirectorySeparator = false;
// Continue in this case, potentially writing out '\'.
}
if (numSpaces > 0 && firstSegment)
{
// Handle strings like " \\server\share".
if (index + 1 < path.Length && PathInternal.IsDirectorySeparator(path[index + 1]))
{
newBuffer.Append(DirectorySeparatorChar);
}
}
}
numDots = 0;
numSpaces = 0; // Suppress trailing spaces
if (!fixupDirectorySeparator)
{
fixupDirectorySeparator = true;
newBuffer.Append(DirectorySeparatorChar);
}
numSigChars = 0;
lastSigChar = index;
startedWithVolumeSeparator = false;
firstSegment = false;
// For short file names, we must try to expand each of them as
// soon as possible. We need to allow people to specify a file
// name that doesn't exist using a path with short file names
// in it, such as this for a temp file we're trying to create:
// C:\DOCUME~1\USERNA~1.RED\LOCALS~1\Temp\bg3ylpzp
// We could try doing this afterwards piece by piece, but it's
// probably a lot simpler to do it here.
if (mightBeShortFileName)
{
newBuffer.TryExpandShortFileName();
mightBeShortFileName = false;
}
int thisPos = newBuffer.Length - 1;
if (thisPos - lastDirectorySeparatorPos > MaxComponentLength + 1)
{
// Components can be up to 255 characters plus an additional null,
// so separators can be 256 characters apart
throw new PathTooLongException(SR.IO_PathTooLong);
}
lastDirectorySeparatorPos = thisPos;
} // if (Found directory separator)
else if (currentChar == '.')
{
// Reduce only multiple .'s only after slash to 2 dots. For
// instance a...b is a valid file name.
numDots++;
// Don't flush out non-terminal spaces here, because they may in
// the end not be significant. Turn "c:\ . .\foo" -> "c:\foo"
// which is the conclusion of removing trailing dots & spaces,
// as well as folding multiple '\' characters.
}
else if (currentChar == ' ')
{
numSpaces++;
}
else
{ // Normal character logic
if (currentChar == '~' && expandShortPaths)
mightBeShortFileName = true;
fixupDirectorySeparator = false;
// To reject strings like "C:...\foo" and "C :\foo"
if (firstSegment && currentChar == VolumeSeparatorChar)
{
// Only accept "C:", not "c :" or ":"
// Get a drive letter or ' ' if index is 0.
char driveLetter = (index > 0) ? path[index - 1] : ' ';
bool validPath = ((numDots == 0) && (numSigChars >= 1) && (driveLetter != ' '));
if (!validPath)
throw new ArgumentException(SR.Arg_PathIllegal);
startedWithVolumeSeparator = true;
// We need special logic to make " c:" work, we should not fix paths like " foo::$DATA"
if (numSigChars > 1)
{ // Common case, simply do nothing
int spaceCount = 0; // How many spaces did we write out, numSpaces has already been reset.
while ((spaceCount < newBuffer.Length) && newBuffer[spaceCount] == ' ')
spaceCount++;
if (numSigChars - spaceCount == 1)
{
//Safe to update stack ptr directly
newBuffer.Length = 0;
newBuffer.Append(driveLetter); // Overwrite spaces, we need a special case to not break " foo" as a relative path.
}
}
numSigChars = 0;
}
else
{
numSigChars += 1 + numDots + numSpaces;
}
// Copy any spaces & dots since the last significant character
// to here. Note we only counted the number of dots & spaces,
// and don't know what order they're in. Hence the copy.
if (numDots > 0 || numSpaces > 0)
{
int numCharsToCopy = (lastSigChar >= 0) ? index - lastSigChar - 1 : index;
if (numCharsToCopy > 0)
{
for (int i = 0; i < numCharsToCopy; i++)
{
newBuffer.Append(path[lastSigChar + 1 + i]);
}
}
numDots = 0;
numSpaces = 0;
}
newBuffer.Append(currentChar);
lastSigChar = index;
}
index++;
} // end while
// Components can be up to 255 characters plus an additional null
if (newBuffer.Length - lastDirectorySeparatorPos > MaxComponentLength)
{
throw new PathTooLongException(SR.IO_PathTooLong);
}
// Drop any trailing dots and spaces from file & directory names, EXCEPT
// we MUST make sure that "C:\foo\.." is correctly handled.
// Also handle "C:\foo\." -> "C:\foo", while "C:\." -> "C:\"
if (numSigChars == 0)
{
if (numDots > 0)
{
// Look for ".[space]*" or "..[space]*"
int start = lastSigChar + 1;
if (path[start] != '.')
throw new ArgumentException(SR.Arg_PathIllegal);
// Only allow "[dot]+[space]*", and normalize the
// legal ones to "." or ".."
if (numDots >= 2)
{
// Reject "C:..."
if (startedWithVolumeSeparator && numDots > 2)
throw new ArgumentException(SR.Arg_PathIllegal);
if (path[start + 1] == '.')
{
// Search for a space in the middle of the
// dots and throw
for (int i = start + 2; i < start + numDots; i++)
{
if (path[i] != '.')
throw new ArgumentException(SR.Arg_PathIllegal);
}
numDots = 2;
}
else
{
if (numDots > 1)
throw new ArgumentException(SR.Arg_PathIllegal);
numDots = 1;
}
}
if (numDots == 2)
{
newBuffer.Append('.');
}
newBuffer.Append('.');
}
} // if (numSigChars == 0)
// If we ended up eating all the characters, bail out.
if (newBuffer.Length == 0)
throw new ArgumentException(SR.Arg_PathIllegal);
// Disallow URL's here. Some of our other Win32 API calls will reject
// them later, so we might be better off rejecting them here.
// Note we've probably turned them into "file:\D:\foo.tmp" by now.
// But for compatibility, ensure that callers that aren't doing a
// full check aren't rejected here.
if (fullCheck)
{
if (newBuffer.OrdinalStartsWith("http:", false) ||
newBuffer.OrdinalStartsWith("file:", false))
{
throw new ArgumentException(SR.Argument_PathUriFormatNotSupported);
}
}
// If the last part of the path (file or directory name) had a tilde,
// expand that too.
if (mightBeShortFileName)
{
newBuffer.TryExpandShortFileName();
}
// Call the Win32 API to do the final canonicalization step.
int result = 1;
if (fullCheck)
{
// NOTE: Win32 GetFullPathName requires the input buffer to be big enough to fit the initial
// path which is a concat of CWD and the relative path, this can be of an arbitrary
// size and could be > MaxPath (which becomes an artificial limit at this point),
// even though the final normalized path after fixing up the relative path syntax
// might be well within the MaxPath restriction. For ex,
// "c:\SomeReallyLongDirName(thinkGreaterThan_MAXPATH)\..\foo.txt" which actually requires a
// buffer well with in the MaxPath as the normalized path is just "c:\foo.txt"
// This buffer requirement seems wrong, it could be a bug or a perf optimization
// like returning required buffer length quickly or avoid stratch buffer etc.
// Either way we need to workaround it here...
// Ideally we would get the required buffer length first by calling GetFullPathName
// once without the buffer and use that in the later call but this doesn't always work
// due to Win32 GetFullPathName bug. For instance, in Win2k, when the path we are trying to
// fully qualify is a single letter name (such as "a", "1", ",") GetFullPathName
// fails to return the right buffer size (i.e, resulting in insufficient buffer).
// To workaround this bug we will start with MaxPath buffer and grow it once if the
// return value is > MaxPath.
result = newBuffer.GetFullPathName();
// If we called GetFullPathName with something like "foo" and our
// command window was in short file name mode (ie, by running edlin or
// DOS versions of grep, etc), we might have gotten back a short file
// name. So, check to see if we need to expand it.
mightBeShortFileName = false;
for (int i = 0; i < newBuffer.Length && !mightBeShortFileName; i++)
{
if (newBuffer[i] == '~' && expandShortPaths)
mightBeShortFileName = true;
}
if (mightBeShortFileName)
{
bool r = newBuffer.TryExpandShortFileName();
// Consider how the path "Doesn'tExist" would expand. If
// we add in the current directory, it too will need to be
// fully expanded, which doesn't happen if we use a file
// name that doesn't exist.
if (!r)
{
int lastSlash = -1;
for (int i = newBuffer.Length - 1; i >= 0; i--)
{
if (newBuffer[i] == DirectorySeparatorChar)
{
lastSlash = i;
break;
}
}
if (lastSlash >= 0)
{
// This bounds check is for safe memcpy but we should never get this far
if (newBuffer.Length >= maxPathLength)
throw new PathTooLongException(SR.IO_PathTooLong);
int lenSavedName = newBuffer.Length - lastSlash - 1;
Debug.Assert(lastSlash < newBuffer.Length, "path unexpectedly ended in a '\'");
newBuffer.Fixup(lenSavedName, lastSlash);
}
}
}
}
if (result != 0)
{
/* Throw an ArgumentException for paths like \\, \\server, \\server\
This check can only be properly done after normalizing, so
\\foo\.. will be properly rejected. */
if (newBuffer.Length > 1 && newBuffer[0] == '\\' && newBuffer[1] == '\\')
{
int startIndex = 2;
while (startIndex < result)
{
if (newBuffer[startIndex] == '\\')
{
startIndex++;
break;
}
else
{
startIndex++;
}
}
if (startIndex == result)
throw new ArgumentException(SR.Arg_PathIllegalUNC);
}
}
// Check our result and form the managed string as necessary.
if (newBuffer.Length >= maxPathLength)
throw new PathTooLongException(SR.IO_PathTooLong);
if (result == 0)
{
int errorCode = Marshal.GetLastWin32Error();
if (errorCode == 0)
errorCode = Interop.mincore.Errors.ERROR_BAD_PATHNAME;
throw Win32Marshal.GetExceptionForWin32Error(errorCode, path);
}
string returnVal = newBuffer.ToString();
if (string.Equals(returnVal, path, StringComparison.Ordinal))
{
returnVal = path;
}
return returnVal;
}
