max / makenotwork

2.4 KB · 67 lines History Blame Raw

1	/// Cross-check the in-house ELF read against binutils on whatever binaries this
2	/// machine happens to have. Not a unit test of the parser (those live beside it);
3	/// a differential against the tool everyone else would have used.
4	#[test]
5	fn compare_against_readelf() {
6	// Skip where binutils is not installed rather than failing: this is a
7	// differential, and with nothing to differ against there is nothing to say.
8	if std::process::Command::new("readelf")
9	.arg("--version")
10	.output()
11	.is_err()
12	{
13	eprintln!("no readelf on this machine; skipping the differential");
14	return;
15	}
16	let mut checked = 0;
17	let candidates: Vec<String> = std::fs::read_dir("/usr/bin")
18	.into_iter()
19	.flatten()
20	.flatten()
21	.map(\|e\| e.path().to_string_lossy().into_owned())
22	.take(400)
23	.collect();
24	for p in candidates {
25	let Ok(bytes) = std::fs::read(&p) else {
26	continue;
27	};
28	if bytes.len() < 64 \|\| &bytes[..4] != b"\x7fELF" {
29	continue;
30	}
31	let mine = sando_daemon::elf::glibc_floor(&bytes).map(\|v\| v.to_string());
32	let Ok(out) = std::process::Command::new("readelf")
33	.args(["-V", &p])
34	.output()
35	else {
36	continue;
37	};
38	if !out.status.success() {
39	continue;
40	}
41	let s = String::from_utf8_lossy(&out.stdout);
42	// Only the version-requirement section; readelf -V also prints defined
43	// versions, which are not what a floor is made of.
44	let req = match s.split_once("Version needs section") {
45	Some((_, rest)) => rest,
46	None => "",
47	};
48	let mut best: Option<(u32, u32)> = None;
49	for tok in req.split(\|c: char\| !(c.is_alphanumeric() \|\| c == '.' \|\| c == '_')) {
50	if let Some(v) = tok.strip_prefix("GLIBC_")
51	&& let Some((a, b)) = v.split_once('.')
52	&& let (Ok(a), Ok(b)) = (a.parse::<u32>(), b.parse::<u32>())
53	{
54	best = Some(best.map_or((a, b), \|x\| x.max((a, b))));
55	}
56	}
57	let theirs = best.map(\|(a, b)\| format!("{a}.{b}"));
58	assert_eq!(mine, theirs, "disagreed on {p}");
59	checked += 1;
60	}
61	println!("agreed with readelf on {checked} binaries");
62	assert!(
63	checked > 20,
64	"only {checked} binaries compared; too few to mean anything"
65	);
66	}
67