[PATCH v1 bpf-next 5/9] bpftool: add test for bpftool prog

[Manu Bretelle <chantr4@gmail.com>]

Add tests that validate `bpftool prog list` functions, that we can
associate pids with them, and that we can show a prog by id.

    $ BPFTOOL_PATH=../bpftool
    CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_RUNNER="sudo -E" cargo test --
    --nocapture
        Finished test [unoptimized + debuginfo] target(s) in 0.05s
         Running unittests src/main.rs
    (target/debug/deps/bpftool_tests-afa5a7eef3cdeafb)

    running 6 tests
    Running command "../bpftool" "version"
    test bpftool_tests::run_bpftool ... ok
    Running command "../bpftool" "map" "list" "--json"
    Running command "../bpftool" "prog" "list" "--json"
    Running command "../bpftool" "prog" "list" "--json"
    Running command "../bpftool" "map" "list" "--json"
    Running command "../bpftool" "prog" "show" "id" "3160417" "--json"
    test bpftool_tests::run_bpftool_prog_show_id ... ok
    test bpftool_tests::run_bpftool_map_pids ... ok
    test bpftool_tests::run_bpftool_map_list ... ok
    test bpftool_tests::run_bpftool_prog_pids ... ok
    test bpftool_tests::run_bpftool_prog_list ... ok

    test result: ok. 6 passed; 0 failed; 0 ignored; 0 measured; 0 filtered
    out; finished in 0.20s

Signed-off-by: Manu Bretelle <chantr4@gmail.com>
---
 .../bpftool_tests/src/bpf/bpftool_tests.bpf.c |  2 +-
 .../bpf/bpftool_tests/src/bpftool_tests.rs    | 79 ++++++++++++++++++-
 2 files changed, 79 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/bpftool_tests/src/bpf/bpftool_tests.bpf.c b/tools/testing/selftests/bpf/bpftool_tests/src/bpf/bpftool_tests.bpf.c
index dbd4e2aad277..e2b18dd36207 100644
--- a/tools/testing/selftests/bpf/bpftool_tests/src/bpf/bpftool_tests.bpf.c
+++ b/tools/testing/selftests/bpf/bpftool_tests/src/bpf/bpftool_tests.bpf.c
@@ -14,7 +14,7 @@ struct {
 int my_pid = 0;
 
 SEC("tp/syscalls/sys_enter_write")
-int handle_tp(void *ctx)
+int handle_tp_sys_enter_write(void *ctx)
 {
 	int pid = bpf_get_current_pid_tgid() >> 32;
 
diff --git a/tools/testing/selftests/bpf/bpftool_tests/src/bpftool_tests.rs b/tools/testing/selftests/bpf/bpftool_tests/src/bpftool_tests.rs
index a832b255e988..695a1cbc5be8 100644
--- a/tools/testing/selftests/bpf/bpftool_tests/src/bpftool_tests.rs
+++ b/tools/testing/selftests/bpf/bpftool_tests/src/bpftool_tests.rs
@@ -8,9 +8,10 @@ mod bpftool_tests_skel {
 use bpftool_tests_skel::BpftoolTestsSkelBuilder;
 use libbpf_rs::skel::OpenSkel;
 use libbpf_rs::skel::SkelBuilder;
+use libbpf_rs::Program;
 use serde::Deserialize;
 use serde::Serialize;
-
+use std::os::fd::AsFd;
 use std::process::Command;
 
 const BPFTOOL_PATH_ENV: &str = "BPFTOOL_PATH";
@@ -23,6 +24,17 @@ struct Pid {
     pid: u64,
 }
 
+/// A struct representing a prog entry from `bpftool prog list -j`
+#[derive(Serialize, Deserialize, Debug)]
+struct Prog {
+    name: Option<String>,
+    id: u32,
+    r#type: String,
+    tag: String,
+    #[serde(default)]
+    pids: Vec<Pid>,
+}
+
 /// A struct representing a map entry from `bpftool map list -j`
 #[derive(Serialize, Deserialize, Debug)]
 struct Map {
@@ -101,3 +113,68 @@ fn run_bpftool_map_pids() {
         map.pids
     );
 }
+
+/// A test to validate that we can list programs using bpftool
+#[test]
+fn run_bpftool_prog_list() {
+    let _skel = setup().expect("Failed to set up BPF program");
+    let output = run_bpftool_command(&["prog", "list", "--json"]);
+
+    let progs = serde_json::from_slice::<Vec<Prog>>(&output.stdout).expect("Failed to parse JSON");
+
+    assert!(output.status.success());
+    assert!(!progs.is_empty(), "No programs were listed");
+}
+
+/// A test to validate that we can find PIDs associated with a program
+#[test]
+fn run_bpftool_prog_pids() {
+    let hook_name = "handle_tp_sys_enter_write";
+
+    let _skel = setup().expect("Failed to set up BPF program");
+    let output = run_bpftool_command(&["prog", "list", "--json"]);
+
+    let progs = serde_json::from_slice::<Vec<Prog>>(&output.stdout).expect("Failed to parse JSON");
+    assert!(output.status.success(), "bpftool returned an error.");
+
+    // `handle_tp_sys_enter_write` is a hook our bpftool_tests.bpf.c attaches
+    // to (tp/syscalls/sys_enter_write).
+    // It should have at least one entry for our current process.
+    let prog = progs
+        .iter()
+        .find(|m| m.name.is_some() && m.name.as_ref().unwrap() == hook_name)
+        .unwrap_or_else(|| panic!("Did not find {} prog", hook_name));
+
+    let mypid = std::process::id() as u64;
+    assert!(
+        prog.pids.iter().any(|p| p.pid == mypid),
+        "Did not find test runner pid ({}) in pids list associated with prog *{}*: {:?}",
+        mypid,
+        hook_name,
+        prog.pids
+    );
+}
+
+/// A test to validate that we can run `bpftool prog show <id>`
+/// an extract the expected information.
+#[test]
+fn run_bpftool_prog_show_id() {
+    let skel = setup().expect("Failed to set up BPF program");
+    let binding = skel.progs();
+    let handle_tp_sys_enter_write = binding.handle_tp_sys_enter_write();
+    let prog_id =
+        Program::get_id_by_fd(handle_tp_sys_enter_write.as_fd()).expect("Failed to get prog ID");
+
+    let output = run_bpftool_command(&["prog", "show", "id", &prog_id.to_string(), "--json"]);
+    assert!(output.status.success(), "bpftool returned an error.");
+
+    let prog = serde_json::from_slice::<Prog>(&output.stdout).expect("Failed to parse JSON");
+
+    assert_eq!(prog_id, prog.id);
+    assert_eq!(
+        handle_tp_sys_enter_write.name(),
+        prog.name
+            .expect("Program handle_tp_sys_enter_write has no name")
+    );
+    assert_eq!("tracepoint", prog.r#type);
+}
-- 
2.39.3