/tmp/myst* files are not cleaned up in case a program fails

[vtikoo]

If a program aborts or segfaults when run with mystikos, we don't get a chance to clean /tmp files.

[bodzhang]

@vtikoo , please add more information about the issue

[AevaOnline]

Discussed some concerns and possible approaches with @paulcallen and @mikbras. Potential solutions include:

• use a ramfs for the temp dir, or
• use a stream object for signing or file mutations, or
• declare signal traps to clean up the directory, and/or
• always use a per-process unique temp dir (e.g., /tmp/mysql-abc123/*), and never place files directly in /tmp/

[paulcallen]

looks like rootfs and elf image files. There is also empty directories that are owned by root

[mikbras]

Here is a solution but will require some rework.

    int fd = mkstemp(template);
    unlink(template);
    // use fd to access file; file blocks are reclaimed on close or when process dies.