Add test case for program order in native module (#3686)

* add test for program order

* Apply suggestions from code review

Co-authored-by: Dave Thaler <[email protected]>

* cr comments

---------

Co-authored-by: Dave Thaler <[email protected]>

tests/api_test/api_test.cpp

@@ -1334,3 +1334,49 @@ TEST_CASE("test_ringbuffer_wraparound", "[stress]")
     // Clean up.
     bpf_object__close(object);
 }
+
+TEST_CASE("Test program order", "[native_tests]")
+{
+    struct bpf_object* object = nullptr;
+    fd_t program_fd;
+    uint32_t program_count = 4;
+    int result;
+
+    REQUIRE(
+        _program_load_helper(
+            "multiple_programs.sys", BPF_PROG_TYPE_SAMPLE, EBPF_EXECUTION_NATIVE, &object, &program_fd) == 0);
+
+    // Get all 4 programs in the native object, and invoke them using bpf_prog_test_run.
+    //
+    // If there is a mismatch in the sorting order of bpf2c and ebpfapi, the 4 eBPF programs
+    // in this object file will be initialized with wrong handles. That will cause wrong programs
+    // to be invoked when bpf_prog_test_run is called. Since each program returns a different value,
+    // we can validate that the correct / expected program was invoked by checking the return value.
+    for (uint32_t i = 0; i < program_count; i++) {
+        bpf_test_run_opts opts = {};
+        bind_md_t ctx = {};
+        std::string program_name = "program" + std::to_string(i + 1);
+        struct bpf_program* program = bpf_object__find_program_by_name(object, program_name.c_str());
+        REQUIRE(program != nullptr);
+        program_fd = bpf_program__fd(program);
+        REQUIRE(program_fd > 0);
+
+        std::string app_id = "api_test.exe";
+
+        opts.ctx_in = &ctx;
+        opts.ctx_size_in = sizeof(ctx);
+        opts.ctx_out = &ctx;
+        opts.ctx_size_out = sizeof(ctx);
+        opts.data_in = app_id.data();
+        opts.data_size_in = static_cast<uint32_t>(app_id.size());
+        opts.data_out = app_id.data();
+        opts.data_size_out = static_cast<uint32_t>(app_id.size());
+
+        result = bpf_prog_test_run_opts(program_fd, &opts);
+        REQUIRE(result == 0);
+        REQUIRE(opts.retval == (i + 1));
+    }
+
+    // Clean up.
+    bpf_object__close(object);
+}

tests/sample/multiple_programs.c

@@ -0,0 +1,43 @@
+// Copyright (c) eBPF for Windows contributors
+// SPDX-License-Identifier: MIT
+
+// Whenever this sample program changes, bpf2c_tests will fail unless the
+// expected files in tests\bpf2c_tests\expected are updated. The following
+// script can be used to regenerate the expected files:
+//     generate_expected_bpf2c_output.ps1
+//
+// Usage:
+// .\scripts\generate_expected_bpf2c_output.ps1 <build_output_path>
+// Example:
+// .\scripts\generate_expected_bpf2c_output.ps1 .\x64\Debug\
+
+#include "bpf_helpers.h"
+#include "ebpf_nethooks.h"
+
+SEC("bind_2")
+int
+program3(bind_md_t* ctx)
+{
+    return 3;
+}
+
+SEC("bind_4")
+int
+program1(bind_md_t* ctx)
+{
+    return 1;
+}
+
+SEC("bind_3")
+int
+program2(bind_md_t* ctx)
+{
+    return 2;
+}
+
+SEC("bind_1")
+int
+program4(bind_md_t* ctx)
+{
+    return 4;
+}

tests/sample/sample.vcxproj.filters

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <!--
   Copyright (c) eBPF for Windows contributors
   SPDX-License-Identifier: MIT
@@ -123,5 +123,8 @@
     <CustomBuild Include="cgroup_sendto_count3.c">
       <Filter>Source Files</Filter>
     </CustomBuild>
+    <CustomBuild Include="multiple_programs.c">
+      <Filter>Source Files</Filter>
+    </CustomBuild>
   </ItemGroup>
 </Project>