/// <summary>
/// Allocates the specified pin.
/// </summary>
/// <param name="pin">The pin.</param>
/// <param name="direction">The direction.</param>
public void Allocate(ProcessorPin pin, PinDirection direction)
{
var gpioId = string.Format("gpio{0}", (int)pin);
if (Directory.Exists(Path.Combine(gpioPath, gpioId)))
{
// Reinitialize pin virtual file
using (var streamWriter = new StreamWriter(Path.Combine(gpioPath, "unexport"), false))
{
streamWriter.Write((int)pin);
streamWriter.Close();
}
}
// Export pin for file mode
using (var streamWriter = new StreamWriter(Path.Combine(gpioPath, "export"), false))
{
streamWriter.Write((int)pin);
streamWriter.Close();
}
// Set the direction on the pin and update the exported list
SetPinMode(pin, direction == PinDirection.Input ? Interop.BCM2835_GPIO_FSEL_INPT : Interop.BCM2835_GPIO_FSEL_OUTP);
if (Environment.OSVersion.Platform == PlatformID.Unix)
{
UnixDirectoryInfo udi = new UnixDirectoryInfo(Path.Combine(gpioPath, gpioId));
while ((udi.OwnerGroup.GroupName != "gpio") &&
(!udi.CanAccess(AccessModes.W_OK)))
{
Thread.Sleep(1);
udi.Refresh();
}
}
// Set direction in pin virtual file
var filePath = Path.Combine(gpioId, "direction");
using (var streamWriter = new StreamWriter(Path.Combine(gpioPath, filePath), false))
{
streamWriter.Write(direction == PinDirection.Input ? "in" : "out");
}
if (direction == PinDirection.Input)
{
PinResistor pinResistor;
if (!pinResistors.TryGetValue(pin, out pinResistor) || pinResistor != PinResistor.None)
{
SetPinResistor(pin, PinResistor.None);
}
SetPinDetectedEdges(pin, PinDetectedEdges.Both);
InitializePoll(pin);
}
}
private bool DirectoryIsSuitable(string folderToTest)
{
// A directory with invalid characters isn't suitable
string pathToTest = null;
try
{
pathToTest = Path.GetFullPath(folderToTest);
}
catch (Exception)
{
return(false);
}
// A directory doesn't have to exist yet to be suitable but if the root directory isn't suitable that's not good
while (!Directory.Exists(pathToTest))
{
if (String.IsNullOrEmpty(pathToTest.Trim()))
{
return(false);
}
pathToTest = Path.GetDirectoryName(pathToTest);
}
if (!MiscUtils.IsUnix)
{
// Check the OS file permissions for the folder
var accessControlList = Directory.GetAccessControl(pathToTest);
var accessRules = accessControlList.GetAccessRules(true, true, typeof(SecurityIdentifier));
var readAllowed = false;
var writeAllowed = false;
foreach (FileSystemAccessRule rule in accessRules)
{
//If we find one that matches the identity we are looking for
using (var currentUserIdentity = WindowsIdentity.GetCurrent())
{
var userName = currentUserIdentity.User.Value;
if (
rule.IdentityReference.Value.Equals(userName, StringComparison.CurrentCultureIgnoreCase) ||
currentUserIdentity.Groups.Contains(rule.IdentityReference))
{
if ((FileSystemRights.Read & rule.FileSystemRights) == FileSystemRights.Read)
{
if (rule.AccessControlType == AccessControlType.Allow)
{
readAllowed = true;
}
if (rule.AccessControlType == AccessControlType.Deny)
{
return(false);
}
}
if ((FileSystemRights.Write & rule.FileSystemRights) == FileSystemRights.Write)
{
if (rule.AccessControlType == AccessControlType.Allow)
{
writeAllowed = true;
}
if (rule.AccessControlType == AccessControlType.Deny)
{
return(false);
}
}
}
}
return(readAllowed && writeAllowed);
}
}
#if __MonoCS__
var ufi = new UnixDirectoryInfo(pathToTest);
return(ufi.CanAccess(Mono.Unix.Native.AccessModes.R_OK) && ufi.CanAccess(Mono.Unix.Native.AccessModes.W_OK)); // accessible for writing
#else
return(false); // unreachable in practice
#endif
}
