Symlinks on Windows require privilege escalation

[dimo414]

On Windows bkt fails with this error:

> /bkt.exe -- ipconfig
bkt: Cache write failed: A required privilege is not held by the client. (os error 1314)

This comes from the call to std::os::windows::fs::symlink_file which actually doesn't work in most cases. Specifically, Windows treats symlink creation as a privileged action and there aren't a lot of good ways around it.

• Python suggests running as an administrator, enabling Developer Mode, or setting SeCreateSymbolicLinkPrivilege
  • Setting the create symlink privilege doesn't always work either; administrators seemingly can't set this for themselves; UAC would need to be disabled
• Some users report success calling mklink in a subprocess, but doesn't work for me, at least. For posterity:

  #[cfg(windows)]
  fn symlink<P: AsRef<Path>, Q: AsRef<Path>>(original: P, link: Q) -> Result<()> {
      let result = Command::new("cmd")
          .arg("/C").arg("mklink")
          .arg(link.as_ref().as_os_str())
          .arg(original.as_ref().as_os_str())
          .output().context("mklink subprocess failed")?;
      if !result.status.success() {
          return Err(Error::msg("Failed to create symlink"))
              .context(format!("Details: {:?}", result));
      }
      Ok(())
  }

• GoLang appears to have given up on symlinks outright and just does extra copies

Rather than making users jump through these hoops, it might be easiest to just manually reimplement "symlinks" as vanilla text files, so the key file would simply contain the path to the data file and lookup() would read that file to find where the data is stored.