Reimplement BpfProgram

Author: r41k0u

src/core/bpf_object.cpp

@@ -65,7 +65,7 @@ void BpfObject::load() {
     }
 
     if (bpf_object__load(obj_)) {
-	std::string error_msg = " object from file '" + object_path_ + "': " + std::strerror(errno);
+	error_msg += " object from file '" + object_path_ + "': " + std::strerror(errno);
         bpf_object__close(obj_);
         obj_ = nullptr;
         throw BpfException(error_msg);

src/core/bpf_program.cpp

@@ -1,84 +1,73 @@
 #include "bpf_program.h"
 #include "bpf_exception.h"
-#include <filesystem>
 #include <utility>
+#include <cerrno>
 
-BpfProgram::BpfProgram(std::string object_path, std::string program_name)
-    : obj_(nullptr), prog_(nullptr), link_(nullptr),
-      object_path_(std::move(object_path)), program_name_(std::move(program_name)) {
+BpfProgram::BpfProgram(std::shared_ptr<BpfObject> parent, struct bpf_program *raw_prog, const std::string& program_name)
+    : parent_obj_(parent),
+      prog_(raw_prog),
+      link_(nullptr),
+      program_name_(program_name) {
+    if (!parent)
+	throw BpfException("Parent BpfObject is null");
+    if (!raw_prog)
+	throw BpfException("bpf_program pointer is null");
 }
 
 BpfProgram::~BpfProgram() {
-    destroy();
-    if (obj_) {
-        bpf_object__close(obj_);
-    }
+    detach();
 }
 
-struct bpf_object * BpfProgram::get_obj() const {
-    return obj_;
+BpfProgram::BpfProgram(BpfProgram&& other) noexcept
+    : parent_obj_(std::move(other.parent_obj_)),
+      prog_(other.prog_),
+      link_(other.link_),
+      program_name_(std::move(other.program_name_)) {
+    
+    other.prog_ = nullptr;
+    other.link_ = nullptr;
 }
 
-bool BpfProgram::load() {
-    // Open the eBPF object file
-    obj_ = bpf_object__open_file(object_path_.c_str(), nullptr);
-    if (libbpf_get_error(obj_)) {
-        throw BpfException("Failed to open BPF object file: " + object_path_);
+BpfProgram& BpfProgram::operator=(BpfProgram&& other) noexcept {
+    if (this != &other) {
+        detach();
+        
+        parent_obj_ = std::move(other.parent_obj_);
+        prog_ = other.prog_;
+        link_ = other.link_;
+        program_name_ = std::move(other.program_name_);
+        
+        other.prog_ = nullptr;
+        other.link_ = nullptr;
     }
+    return *this;
+}
 
-    // Find the program by name (if specified)
-    if (!program_name_.empty()) {
-        prog_ = bpf_object__find_program_by_name(obj_, program_name_.c_str());
-        if (!prog_) {
-            throw BpfException("Program '" + program_name_ + "' not found in object");
-        }
-    } else {
-        while ((prog_ = bpf_object__next_program(obj_, prog_)) != nullptr) {
-            programs.emplace_back(prog_, nullptr);
-        }
-
-        // throw if no programs found
-        if (programs.empty()) {
-            throw BpfException("No programs found in object file");
-        }
+void BpfProgram::attach() {
+    // Check if parent is still alive
+    auto parent = parent_obj_.lock();
+    if (!parent) {
+        throw BpfException("Parent BpfObject has been destroyed");
     }
-
-    // Load the eBPF object into the kernel
-    if (bpf_object__load(obj_)) {
-        throw BpfException("Failed to load BPF object into kernel");
+    
+    if (link_) {
+        throw BpfException("Program '" + program_name_ + "' already attached");
     }
-
-    return true;
-}
-
-bool BpfProgram::attach() {
-    for (auto [prog, link]: programs) {
-        if (!prog) {
-            throw BpfException("Program not loaded");
-        }
-
-        link = bpf_program__attach(prog);
-        if (libbpf_get_error(link)) {
-            link = nullptr;
-            throw BpfException("Failed to attach BPF program");
-        }
+    
+    if (!prog_) {
+        throw BpfException("Program '" + program_name_ + "' not initialized");
     }
-
-    return true;
-}
-
-bool BpfProgram::destroy() {
-    bool success = true;
-    for (auto [prog, link]: programs) {
-        if (!prog) {
-            throw BpfException("Program not loaded");
-        }
-        success = success & bpf_link__destroy(link);
+    
+    link_ = bpf_program__attach(prog_);
+    if (!link_) {
+	std::string err_msg = "bpf_program__attach failed for program '" + program_name_ + "': " + std::strerror(errno);
+        throw BpfException(err_msg);
     }
-    return success;
 }
 
-void BpfProgram::load_and_attach() {
-    load();
-    attach();
+void BpfProgram::detach() {
+    if (link_) {
+        bpf_link__destroy(link_);
+        link_ = nullptr;
+    }
 }

src/core/bpf_program.h

@@ -16,7 +16,7 @@ class BpfProgram {
     std::string program_name_;
 
 public:
-    explicit BpfProgram(std::shared_ptr<BpfObject> parent, struct bpf_program *raw_prog, std::string program_name = "");
+    explicit BpfProgram(std::shared_ptr<BpfObject> parent, struct bpf_program *raw_prog, const std::string& program_name);
 
     ~BpfProgram();
 
@@ -28,8 +28,6 @@ class BpfProgram {
     bool attach();
     bool detach();
 
-    void load_and_attach();
-
     [[nodiscard]] bool is_attached() const { return link_ != nullptr; }
     [[nodiscard]] std::string get_name() const { return program_name_; }
 };