Improve error message for when devices are mounted or in use

[ifd3f]

Describe the bug

A clear and concise description of what the bug is.

To Reproduce

Steps to reproduce the behavior:

1. Plug in a USB
2. ./caligula-x86_64-darwin burn caligula-x86_64-darwin
3. Go through the prompts
4. Select the plugged USB
5. The osascript prompt pops up. Entering in the password, however, does not appear to grant sudo, and the password is asked in the terminal again.
6. Running yields the error

Full terminal output:

> ./caligula-x86_64-darwin burn caligula-x86_64-darwin
Couldn't detect compression format for caligula-x86_64-darwin
> What format to use? no compression
> What is the file's hash?
Input is empty
> What is the file's hash?
Input is empty
? What is the file's hash? <canceled>
> Select target disk disk2 | Generic STORAGE DEVICE Media - 62.6 GB (disk, remov
able: yes)
Input: caligula-x86_64-darwin
  Size: 4.0 MB
  Compression: no compression

Output: disk2
  Model: Generic STORAGE DEVICE Media
  Size: 62.6 GB
  Type: disk
  Path: /dev/rdisk2
  Removable: yes

> Is this okay? Yes
> We don't have permissions on /dev/rdisk2. Escalate using sudo? Yes

Password:
An unexpected error occurred: panicked at src/ui/main.rs:36:9:
Explicit failure signaled: Some(UnknownChildProcError("Resource busy (os error 16)"))

Please report bugs to https://github.com/ifd3f/caligula/issues and attach the following log files, if they exist:
- /var/folders/f1/0sb8zs9d5ps5pt4h1w9g8zzm0000gp/T/caligula/log/1714949843182.main.log
- /var/folders/f1/0sb8zs9d5ps5pt4h1w9g8zzm0000gp/T/caligula/log/1714949843182.child.log

Expected behavior

You only get asked for password once, and the burn happens

Log files

1714949843182.child.log
1714949843182.main.log

OS/Environment

• OS: MacOS Version 14.2.1 (23C71) x86_64
• Version: v0.4.4
• Distribution channel: release binary

Additional context

N/A

[ifd3f]

It seems that this is because the device is mounted. Unmounting it first gives a different error 1714950829848.child.log 1714950829848.main.log

2024-05-05T23:14:00.846797Z DEBUG caligula::writer_process::child: Opening file caligula-x86_64-darwin
2024-05-05T23:14:00.846821Z DEBUG caligula::writer_process::child: Got input file size size=3998608
2024-05-05T23:14:00.846829Z DEBUG caligula::writer_process::child: Opening /dev/rdisk2 for writing
2024-05-05T23:14:00.916385Z ERROR caligula::writer_process::child: PanicInfo { payload: Any { .. }, message: Some(Failed to write block to disk: Os { code: 22, kind: InvalidInput, message: "Invalid argument" }), location: Location { file: "src/writer_process/child.rs", line: 185, col: 14 }, can_unwind: true, force_no_backtrace: false }

Since it's at this specific line, that implies we opened it correctly, but the first block isn't even being written.

    #[inline]
    fn on_block(&mut self, block: &[u8], _scratch: &mut [u8]) -> Result<(), ErrorType> {
        trace!(block_len = block.len(), "Writing block");

        let written = self
            .file
            .write(block)
            .expect("Failed to write block to disk"); // line 185
        if written != block.len() {
            return Err(ErrorType::EndOfOutput);
        }
        Ok(())
    }

[ifd3f]

Somebody on the fediverse suggested to me that it may be a block size issue. I'll validate this Soon(tm).

[ifd3f]

Technically, this issue is three separate issues:

1. we need a more informative message when device is in use
2. writing is broken due to code: 22, kind: InvalidInput, message: "Invalid argument"
3. osascript/touch ID escalation is also broken

This issue will now only be about 1. I will file separate issues for the other ones.