Command Execution & POSIX Escaping

Because root operations execute through /system/bin/su -c <command_string>, shell injection is a catastrophic risk if arguments contain whitespace, quotes, or control characters. fparted enforces centralized escaping and rigid typing.

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🛡️ The Typed Command Pipeline

flowchart TD
    UI[User Interface Action] -->|Creates| Op[StorageOperation Object]
    Op -->|Validated By| Plan[Command Planner]
    Plan -->|Produces| Cmds[List of PlannedCommand]
    Cmds -->|User Confirms| Exec[Privileged Process Executor]
    Exec -->|Resolves Binary| Reg[Manifest Registry]
    Exec -->|Sanitizes Args| Esc[POSIX Single-Quote Sanitizer]
    Esc -->|Executes via| Su[/system/bin/su -c '...']
    Su -->|Structured Result| Res[ExitCode, Stdout, Stderr, Duration]
    Res -->|Triggers| Scan[Device Rescan]

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🔒 POSIX Single-Quote Sanitization

Arguments are never concatenated with simple space interpolation. The executor applies strict POSIX single-quote escaping:

String sanitizeArgument(String arg) {
  if (arg.contains('\x00')) {
    throw ArgumentError('NUL byte detected in argument');
  }
  // Replace every single quote with '\''
  return "'${arg.replaceAll("'", r"'\''")}'";
}

Examples of Safe Handling

Input String	Sanitized Shell Representation
My USB Drive	'My USB Drive'
Don't Panic	'Don'\''t Panic'
$(rm -rf /)	'$(rm -rf /)' (Treated as literal string, no shell expansion)
/dev/block/sda1; reboot	'/dev/block/sda1; reboot' (Semicolon enclosed, no command chaining)

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⚙️ Deterministic Execution Environment

Commands execute inside a sanitized shell environment to eliminate host variability:

Variable	Value	Purpose
PATH	/data/data/vn.shadichy.parted/files/usr/bin:...	Forces verified toolchain resolution
HOME	/data/data/vn.shadichy.parted/files/home	Isolated home directory
TMPDIR	/data/data/vn.shadichy.parted/files/usr/tmp	Safe scratch directory
LC_ALL	C	Predictable, locale-invariant output from CLI tools