private static uint ChangeGroupId(uint groupId)
{
var oldId = UnixInterop.setfsgid(groupId);
if (oldId == groupId)
{
return(oldId);
}
// This will always fail and is required, because no
// error status gets set by this function.
var currentId = UnixInterop.setfsgid(uint.MaxValue);
if (currentId != groupId)
{
if (currentId != oldId)
{
UnixInterop.setfsgid(oldId);
}
throw new InvalidOperationException();
}
// Set again, because WSL seems to be buggy and accepts
// uint.MaxValue even though it's not a valid group id.
UnixInterop.setfsgid(groupId);
return(oldId);
}
/// <summary>
/// Initializes a new instance of the <see cref="UnixFileSystemIdChanger"/> class.
/// </summary>
/// <param name="logger">The logger.</param>
/// <param name="userId">The user identifier.</param>
/// <param name="groupId">The group identifier.</param>
/// <param name="defaultUserId">The user ID to restore.</param>
/// <param name="defaultGroupId">The group ID to restore.</param>
public UnixFileSystemIdChanger(
ILogger?logger,
long userId,
long groupId,
long defaultUserId,
long defaultGroupId)
{
_logger = logger;
_setUserId = (uint)userId;
_setGroupId = (uint)groupId;
_defaultUserId = (uint)defaultUserId;
_defaultGroupId = (uint)defaultGroupId;
_hasUserInfo = true;
var oldGroupId = ChangeGroupId((uint)groupId);
uint oldUserId;
try
{
oldUserId = ChangeUserId((uint)userId);
}
catch
{
UnixInterop.setfsgid(oldGroupId);
throw;
}
if (oldUserId != defaultUserId || oldGroupId != defaultGroupId)
{
logger?.LogWarning("Switched to user id={userId} (was: {oldUserId}) and group id={groupId} (was: {oldGroupId})", userId, oldUserId, groupId, oldGroupId);
}
}
private static bool TryGetDomainNameUnix(out string domainName, out string errorMessage)
{
unsafe
{
var domainNameBuffer = stackalloc byte[MaxDomainNameLength];
if (UnixInterop.GetDomainName(domainNameBuffer, MaxDomainNameLength) != 0)
{
// This should never happen. According to the man page,
// the only possible errno for getdomainname is ENAMETOOLONG,
// which should only happen if the buffer we supply isn't big
// enough, and we're using a buffer size that the man page
// says is the max for POSIX (and larger than the max for Linux).
domainName = null;
errorMessage = "GetDomainName function failed (POSIX violation).";
return(false);
}
domainName = Marshal.PtrToStringAnsi((IntPtr)domainNameBuffer);
if (string.IsNullOrWhiteSpace(domainName))
{
domainName = NoDomainName;
}
errorMessage = null;
return(true);
}
}
/// <inheritdoc />
public void Dispose()
{
if (_hasUserInfo)
{
var restoreUid = _defaultUserId;
var restoreGid = _defaultGroupId;
var prevGid = UnixInterop.setfsgid(restoreGid);
var prevUid = UnixInterop.setfsuid(restoreUid);
if (prevUid != _setUserId || prevGid != _setGroupId)
{
_logger?.LogWarning(
"Reverted to user id={oldUserId} (was set to: {prevUserId}) and group id={oldGroupId} (was set to: {prevGroupId})",
restoreUid,
prevUid,
restoreGid,
prevGid);
}
}
}
