[PATCH v1 bpf-next 4/9] bpftool: Add test to verify that pids are associated to maps.

[Manu Bretelle <chantr4@gmail.com>]

Signed-off-by: Manu Bretelle <chantr4@gmail.com>
---
 .../bpftool_tests/src/bpf/bpftool_tests.bpf.c |  7 +++++
 .../bpf/bpftool_tests/src/bpftool_tests.rs    | 29 +++++++++++++++++++
 2 files changed, 36 insertions(+)

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 8b92171145de..dbd4e2aad277 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
@@ -4,6 +4,13 @@
 
 char LICENSE[] SEC("license") = "Dual BSD/GPL";
 
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__uint(max_entries, 10240);
+	__type(key, u32);
+	__type(value, u64);
+} pid_write_calls SEC(".maps");
+
 int my_pid = 0;
 
 SEC("tp/syscalls/sys_enter_write")
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 fb58898a4a1a..a832b255e988 100644
--- a/tools/testing/selftests/bpf/bpftool_tests/src/bpftool_tests.rs
+++ b/tools/testing/selftests/bpf/bpftool_tests/src/bpftool_tests.rs
@@ -72,3 +72,32 @@ fn run_bpftool_map_list() {
     assert!(output.status.success(), "bpftool returned an error.");
     assert!(!maps.is_empty(), "No maps were listed");
 }
+
+/// A test to validate that we can find PIDs associated with a map
+#[test]
+fn run_bpftool_map_pids() {
+    let map_name = "pid_write_calls";
+
+    let _skel = setup().expect("Failed to set up BPF program");
+    let output = run_bpftool_command(&["map", "list", "--json"]);
+
+    let maps = serde_json::from_slice::<Vec<Map>>(&output.stdout).expect("Failed to parse JSON");
+
+    assert!(output.status.success(), "bpftool returned an error.");
+
+    // `pid_write_calls` is a map our bpftool_tests.bpf.c uses. It should have at least
+    // one entry for our current process.
+    let map = maps
+        .iter()
+        .find(|m| m.name.is_some() && m.name.as_ref().unwrap() == map_name)
+        .unwrap_or_else(|| panic!("Did not find {} map", map_name));
+
+    let mypid = std::process::id() as u64;
+    assert!(
+        map.pids.iter().any(|p| p.pid == mypid),
+        "Did not find test runner pid ({}) in pids list associated with map *{}*: {:?}",
+        mypid,
+        map_name,
+        map.pids
+    );
+}
-- 
2.39.3