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Windows: Deal with NT namespaced paths in GetFinalPathNameByHandle #17541

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Windows: Deal with NT namespaced paths in GetFinalPathNameByHandle #17541

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36 changes: 28 additions & 8 deletions lib/std/os/windows.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -1291,16 +1291,33 @@ pub fn GetFinalPathNameByHandle(
},
.Dos => {
// parse the string to separate volume path from file path
const expected_prefix = std.unicode.utf8ToUtf16LeStringLiteral("\\Device\\");

// TODO find out if a path can start with something besides `\Device\<volume name>`,
// and if we need to handle it differently
// (i.e. how to determine the start and end of the volume name in that case)
if (!mem.eql(u16, expected_prefix, final_path[0..expected_prefix.len])) return error.Unexpected;
const device_prefix = std.unicode.utf8ToUtf16LeStringLiteral("\\Device\\");

// We aren't entirely sure of the structure of the path returned by
// QueryObjectName in all contexts/environments.
// This code is written to cover the various cases that have
// been encountered and solved appropriately. But note that there's
// no easy way to verify that they have all been tackled!
// (Unless you, the reader knows of one then please do action that!)
if (!mem.eql(u16, device_prefix, final_path[0..device_prefix.len])) {
// Wine seems to return NT namespaced paths from QueryObjectName
// (e.g. `\??\Z:\some\path\to\a\file.txt`), in which case we can just strip the
// prefix to turn it into an absolute paths
const namespace_prefix = getNamespacePrefix(u16, final_path);
if (namespace_prefix == .nt) {
const unprefixed_path = final_path[NamespacePrefix.len..];
// TODO: Handle other possible path types, only drive absolute has been observed so far
if (getUnprefixedPathType(u16, unprefixed_path) != .drive_absolute) {
return error.Unexpected;
}
return unprefixed_path;
}
return error.Unexpected;
}

const file_path_begin_index = mem.indexOfPos(u16, final_path, expected_prefix.len, &[_]u16{'\\'}) orelse unreachable;
const file_path_begin_index = mem.indexOfPos(u16, final_path, device_prefix.len, &[_]u16{'\\'}) orelse unreachable;
const volume_name_u16 = final_path[0..file_path_begin_index];
const device_name_u16 = volume_name_u16[expected_prefix.len..];
const device_name_u16 = volume_name_u16[device_prefix.len..];
const file_name_u16 = final_path[file_path_begin_index..];

// MUP is Multiple UNC Provider, and indicates that the path is a UNC
Expand Down Expand Up @@ -2558,6 +2575,9 @@ pub const NamespacePrefix = enum {
fake_verbatim,
/// `\??\`
nt,

// The length of all the prefixes (except `none`)
pub const len: usize = 4;
};

/// If `T` is `u16`, then `path` should be encoded as WTF-16LE.
Expand Down
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