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Make relocations tests actually pass

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pull/467/head
Matteo Nardi 2 years ago
parent 702f77b565
commit 27f22f205d
1 changed files with 90 additions and 81 deletions
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171
test/integration-test/src/tests/relocations.rs
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@ -1,5 +1,6 @@
use anyhow::{Context, Result};
use std::{process::Command, thread::sleep, time::Duration};
use std::{path::PathBuf, process::Command, thread::sleep, time::Duration};
use tempfile::TempDir;
use aya::{maps::Array, programs::TracePoint, BpfLoader, Btf, Endianness};
@ -51,7 +52,7 @@ fn relocate_enum() {
.build()
.unwrap();
assert_eq!(test.run().unwrap(), 4);
assert_eq!(test.run_no_btf().unwrap(), 0);
assert_eq!(test.run_no_btf().unwrap(), 1);
}
#[integration_test]
@ -61,16 +62,20 @@ fn relocate_pointer() {
struct foo {};
struct bar { struct foo *f; };
"#,
target_btf: r#""#,
target_btf: r#"
struct foo {};
struct bar { struct foo *f; };
"#,
relocation_code: r#"
__u8 memory[] = {0, 0, 0, 0, 0, 0, 0, 42};
__u8 memory[] = {42, 0, 0, 0, 0, 0, 0, 0};
struct foo *f = BPF_CORE_READ((struct bar *)&memory, f);
__u32 value = (f == (struct foo *) 42);
__u32 value = ((__u64) f);
"#,
}
.build()
.unwrap();
assert_eq!(test.run().unwrap(), 1);
assert_eq!(test.run().unwrap(), 42);
assert_eq!(test.run_no_btf().unwrap(), 42);
}
/// Utility code for running relocation tests:
@ -105,57 +110,37 @@ impl RelocationTest {
fn build_ebpf(&self) -> Result<Vec<u8>> {
let local_definition = self.local_definition;
let relocation_code = self.relocation_code;
let tmp_dir = tempfile::tempdir().context("Error making temp dir")?;
let ebpf_file = tmp_dir.path().join("ebpf_program.c");
std::fs::write(
&ebpf_file,
format!(
r#"
#include <linux/bpf.h>
#include <bpf/bpf_core_read.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
{local_definition}
struct {{
__uint(type, BPF_MAP_TYPE_ARRAY);
__type(key, __u32);
__type(value, __u32);
__uint(max_entries, 1);
}} output_map SEC(".maps");
SEC("tracepoint/bpf_prog") int bpf_prog(void *ctx) {{
__u32 key = 0;
{relocation_code}
bpf_map_update_elem(&output_map, &key, &value, BPF_ANY);
return 0;
}}
char _license[] SEC("license") = "GPL";
"#
),
)
.context("Writing bpf program failed")?;
Command::new("clang")
.current_dir(tmp_dir.path())
.args(["-c", "-g", "-O2", "-target", "bpf"])
// NOTE: these tests depend on libbpf, LIBBPF_INCLUDE must point its headers.
// This is set automatically by the integration-test xtask.
.args([
"-I",
&std::env::var("LIBBPF_INCLUDE").context("LIBBPF_INCLUDE not set")?,
])
.arg(&ebpf_file)
.status()
.context("Failed to run clang")?
.success()
.then_some(())
.context("Failed to compile eBPF program")?;
let ebpf = std::fs::read(ebpf_file.with_extension("o"))
.context("Error reading compiled eBPF program")?;
Ok(ebpf)
let (_tmp_dir, compiled_file) = compile(&format!(
r#"
#include <linux/bpf.h>
#include <bpf/bpf_core_read.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
{local_definition}
struct {{
__uint(type, BPF_MAP_TYPE_ARRAY);
__type(key, __u32);
__type(value, __u32);
__uint(max_entries, 1);
}} output_map SEC(".maps");
SEC("tracepoint/bpf_prog") int bpf_prog(void *ctx) {{
__u32 key = 0;
{relocation_code}
bpf_map_update_elem(&output_map, &key, &value, BPF_ANY);
return 0;
}}
char _license[] SEC("license") = "GPL";
"#
))
.context("Failed to compile eBPF program")?;
let bytecode =
std::fs::read(compiled_file).context("Error reading compiled eBPF program")?;
Ok(bytecode)
}
/// - Generate the target BTF source with a mock main()
@ -163,36 +148,33 @@ impl RelocationTest {
/// - Extract the BTF with pahole
fn build_btf(&self) -> Result<Btf> {
let target_btf = self.target_btf;
let tmp_dir = tempfile::tempdir().context("Error making temp dir")?;
let relocation_code = self.relocation_code;
// BTF files can be generated and inspected with these commands:
// $ clang -c -g -O2 -target bpf target.c
// $ pahole --btf_encode_detached=target.btf -V target.o
// $ bpftool btf dump file ./target.btf format c
let btf_file = tmp_dir.path().join("target_btf.c");
std::fs::write(
&btf_file,
format!(
r#"
#include <linux/types.h>
{target_btf}
int main() {{ return 0; }}
"#
),
)
.context("Writing bpf program failed")?;
Command::new("clang")
.current_dir(tmp_dir.path())
.args(["-c", "-g", "-O2", "-target", "bpf"])
.arg(&btf_file)
.status()
.context("Failed to run clang")?
.success()
.then_some(())
.context("Failed to compile BTF")?;
let (tmp_dir, compiled_file) = compile(&format!(
r#"
#include <linux/bpf.h>
#include <bpf/bpf_core_read.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
{target_btf}
int main() {{
// This is needed to make sure to emit BTF for the defined types,
// it could be dead code eliminated if we don't.
{relocation_code};
return value;
}}
"#
))
.context("Failed to compile BTF")?;
Command::new("pahole")
.current_dir(tmp_dir.path())
.arg("--btf_encode_detached=target.btf")
.arg(btf_file.with_extension("o"))
.arg(compiled_file)
.status()
.context("Failed to run pahole")?
.success()
@ -204,6 +186,30 @@ impl RelocationTest {
}
}
/// Compile an eBPF program and return the path of the compiled object.
/// Also returns a TempDir handler, dropping it will clear the created dicretory.
fn compile(source_code: &str) -> Result<(TempDir, PathBuf)> {
let tmp_dir = tempfile::tempdir().context("Error making temp dir")?;
let source = tmp_dir.path().join("source.c");
std::fs::write(&source, source_code).context("Writing bpf program failed")?;
Command::new("clang")
.current_dir(&tmp_dir)
.args(["-c", "-g", "-O2", "-target", "bpf"])
// NOTE: these tests depend on libbpf, LIBBPF_INCLUDE must point its headers.
// This is set automatically by the integration-test xtask.
.args([
"-I",
&std::env::var("LIBBPF_INCLUDE").context("LIBBPF_INCLUDE not set")?,
])
.arg(&source)
.status()
.context("Failed to run clang")?
.success()
.then_some(())
.context("Failed to compile eBPF source")?;
Ok((tmp_dir, source.with_extension("o")))
}
struct RelocationTestRunner {
ebpf: Vec<u8>,
btf: Btf,
@ -212,18 +218,21 @@ struct RelocationTestRunner {
impl RelocationTestRunner {
/// Run test and return the output value
fn run(&self) -> Result<u32> {
self.run_internal(true)
self.run_internal(true).context("Error running with BTF")
}
/// Run without loading btf
fn run_no_btf(&self) -> Result<u32> {
self.run_internal(false)
.context("Error running without BTF")
}
fn run_internal(&self, with_relocations: bool) -> Result<u32> {
let mut loader = BpfLoader::new();
if with_relocations {
loader.btf(Some(&self.btf));
} else {
loader.btf(None);
}
let mut bpf = loader.load(&self.ebpf).context("Loading eBPF failed")?;
let program: &mut TracePoint = bpf

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