private static bool DetermineCanModifyStores()
{
// Check the directory permissions and whether the filesystem supports chmod.
// The only real expected failure from this method is that at the very end
// `stat.Mode == mode` will fail, because fuseblk (NTFS) returns success on chmod,
// but is a no-op.
uint userId = Interop.Sys.GetEUid();
string certStoresFeaturePath = PersistedFiles.GetUserFeatureDirectory("cryptography", "x509stores");
Directory.CreateDirectory(certStoresFeaturePath);
// Check directory permissions:
Interop.Sys.FileStatus dirStat;
if (Interop.Sys.Stat(certStoresFeaturePath, out dirStat) != 0)
{
return(false);
}
if (dirStat.Uid != userId)
{
return(false);
}
if ((dirStat.Mode & (int)Interop.Sys.Permissions.S_IRWXU) != (int)Interop.Sys.Permissions.S_IRWXU)
{
return(false);
}
string probeFilename =
Path.Combine(certStoresFeaturePath, $"{Guid.NewGuid().ToString("N")}.chmod");
try
{
using (FileStream stream = new FileStream(probeFilename, FileMode.Create))
{
Interop.Sys.FileStatus stat;
if (Interop.Sys.FStat(stream.SafeFileHandle, out stat) != 0)
{
return(false);
}
if (stat.Uid != userId)
{
return(false);
}
// The product code here has a lot of stuff it does.
// This capabilities probe will just check that chmod works.
int mode = stat.Mode;
// Flip all of the O bits.
mode ^= (int)Interop.Sys.Permissions.S_IRWXO;
if (Interop.Sys.FChMod(stream.SafeFileHandle, mode) < 0)
{
return(false);
}
// Verify the chmod applied.
if (Interop.Sys.FStat(stream.SafeFileHandle, out stat) != 0)
{
return(false);
}
// On fuseblk (NTFS) this will return false, because the fchmod
// call returned success without being able to actually apply
// mode-bits.
return(stat.Mode == mode);
}
}
finally
{
try
{
File.Delete(probeFilename);
}
catch
{
// Ignore any failure on delete.
}
}
}
private static string GetFolderPathCoreWithoutValidation(SpecialFolder folder)
{
// First handle any paths that involve only static paths, avoiding the overheads of getting user-local paths.
// https://www.freedesktop.org/software/systemd/man/file-hierarchy.html
switch (folder)
{
case SpecialFolder.CommonApplicationData: return("/usr/share");
case SpecialFolder.CommonTemplates: return("/usr/share/templates");
}
if (IsMac)
{
switch (folder)
{
case SpecialFolder.ProgramFiles: return("/Applications");
case SpecialFolder.System: return("/System");
}
}
// All other paths are based on the XDG Base Directory Specification:
// https://specifications.freedesktop.org/basedir-spec/latest/
string home;
try
{
home = PersistedFiles.GetHomeDirectory();
}
catch (Exception exc)
{
Debug.Fail($"Unable to get home directory: {exc}");
home = Path.GetTempPath();
}
Debug.Assert(!string.IsNullOrEmpty(home), "Expected non-null or empty HOME");
// TODO: Consider caching (or precomputing and caching) all subsequent results.
// This would significantly improve performance for repeated access, at the expense
// of not being responsive to changes in the underlying environment variables,
// configuration files, etc.
switch (folder)
{
case SpecialFolder.UserProfile:
case SpecialFolder.MyDocuments: // same value as Personal
return(home);
case SpecialFolder.ApplicationData:
return(GetXdgConfig(home));
case SpecialFolder.LocalApplicationData:
// "$XDG_DATA_HOME defines the base directory relative to which user specific data files should be stored."
// "If $XDG_DATA_HOME is either not set or empty, a default equal to $HOME/.local/share should be used."
string data = GetEnvironmentVariable("XDG_DATA_HOME");
if (string.IsNullOrEmpty(data) || data[0] != '/')
{
data = Path.Combine(home, ".local", "share");
}
return(data);
case SpecialFolder.Desktop:
case SpecialFolder.DesktopDirectory:
return(ReadXdgDirectory(home, "XDG_DESKTOP_DIR", "Desktop"));
case SpecialFolder.Templates:
return(ReadXdgDirectory(home, "XDG_TEMPLATES_DIR", "Templates"));
case SpecialFolder.MyVideos:
return(ReadXdgDirectory(home, "XDG_VIDEOS_DIR", "Videos"));
case SpecialFolder.MyMusic:
return(IsMac ? Path.Combine(home, "Music") : ReadXdgDirectory(home, "XDG_MUSIC_DIR", "Music"));
case SpecialFolder.MyPictures:
return(IsMac ? Path.Combine(home, "Pictures") : ReadXdgDirectory(home, "XDG_PICTURES_DIR", "Pictures"));
case SpecialFolder.Fonts:
return(IsMac ? Path.Combine(home, "Library", "Fonts") : Path.Combine(home, ".fonts"));
case SpecialFolder.Favorites:
if (IsMac)
{
return(Path.Combine(home, "Library", "Favorites"));
}
break;
case SpecialFolder.InternetCache:
if (IsMac)
{
return(Path.Combine(home, "Library", "Caches"));
}
break;
}
// No known path for the SpecialFolder
return(string.Empty);
}
private static string?GetSpecialFolder(SpecialFolder folder)
{
string?home = null;
try
{
home = PersistedFiles.GetHomeDirectory();
}
catch (Exception exc)
{
Debug.Fail($"Unable to get home directory: {exc}");
}
// Fall back to '/' when we can't determine the home directory.
// This location isn't writable by non-root users which provides some safeguard
// that the application doesn't write data which is meant to be private.
if (string.IsNullOrEmpty(home))
{
home = "/";
}
switch (folder)
{
case SpecialFolder.Personal:
case SpecialFolder.LocalApplicationData:
return(home);
case SpecialFolder.ApplicationData:
return(Path.Combine(home, ".config"));
case SpecialFolder.Desktop:
case SpecialFolder.DesktopDirectory:
return(Path.Combine(home, "Desktop"));
case SpecialFolder.MyMusic:
return(Path.Combine(home, "Music"));
case SpecialFolder.MyPictures:
return(Path.Combine(home, "Pictures"));
case SpecialFolder.Templates:
return(Path.Combine(home, "Templates"));
case SpecialFolder.MyVideos:
return(Path.Combine(home, "Videos"));
case SpecialFolder.CommonTemplates:
return("/usr/share/templates");
case SpecialFolder.Fonts:
return(Path.Combine(home, ".fonts"));
case SpecialFolder.UserProfile:
return(GetEnvironmentVariable("HOME"));
case SpecialFolder.CommonApplicationData:
return("/usr/share");
default:
return(string.Empty);
}
}