Mach-O: Parse macOS version #514
Description
This is a quality-of-life feature request: Could goblin parse the minimum macOS version in Mach-O files?
We're currently using custom parsing logic for it (following https://github.com/matthew-brett/delocate/blob/a97bc907ea5fab9256e2c92b995b332605fcd98b/delocate/delocating.py#L468-L480). Parsing the xxxx.yy.zz format is something that sounds like it fits into the scope of a Mach-O reader.
let mut min_macos_version: Option<MacOSVersion> = None;
for cmd in &macho.load_commands {
match cmd.command {
load_command::CommandVariant::BuildVersion(ref build_ver) => {
// LC_BUILD_VERSION is used in modern binaries; platform 1 = MACOS.
if build_ver.platform == 1 {
let version = MacOSVersion::from_packed(build_ver.minos);
min_macos_version = Some(
min_macos_version
.map_or(version, |current| std::cmp::max(current, version)),
);
}
}
load_command::CommandVariant::VersionMinMacosx(ref ver) => {
// LC_VERSION_MIN_MACOSX is used in older binaries.
let version = MacOSVersion::from_packed(ver.version);
min_macos_version = Some(
min_macos_version.map_or(version, |current| std::cmp::max(current, version)),
);
}
_ => {}
}
}
// ...
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
pub struct MacOSVersion {
pub major: u16,
pub minor: u16,
}
impl MacOSVersion {
/// Parse from a packed version (used in Mach-O `LC_BUILD_VERSION` and `LC_VERSION_MIN_MACOSX`).
///
/// Format: `xxxx.yy.zz` where `x` is major, `y` is minor, `z` is patch (ignored).
#[allow(clippy::cast_possible_truncation)]
pub const fn from_packed(packed: u32) -> Self {
Self {
major: ((packed >> 16) & 0xFFFF) as u16,
minor: ((packed >> 8) & 0xFF) as u16,
}
}
}