Add API to remove dynamic entries (ELF)

API Changes (Python / C++):

  * lief.ELF.Binary.remove(DynamicEntry / DYNAMIC_TAGS) - Added
  * lief.ELF.Binary.remove_library

Author: romainthomas

api/python/ELF/objects/pyBinary.cpp

@@ -292,6 +292,16 @@ void init_ELF_Binary_class(py::module& m) {
         "segment"_a, "size"_a,
         py::return_value_policy::reference)
 
+    .def("remove",
+        static_cast<void (Binary::*)(const DynamicEntry&)>(&Binary::remove),
+        "Remove the given " RST_CLASS_REF(lief.ELF.DynamicEntry) " from the dynamic table",
+        "dynamic_entry"_a)
+
+    .def("remove",
+        static_cast<void (Binary::*)(DYNAMIC_TAGS)>(&Binary::remove),
+        "Remove **all** " RST_CLASS_REF(lief.ELF.DynamicEntry) " with the given " RST_CLASS_REF(lief.ELF.DYNAMIC_TAGS) "",
+        "tag"_a)
+
     .def_property_readonly("has_notes",
         &Binary::has_notes,
         "``True`` if the binary contains notes")
@@ -338,6 +348,11 @@ void init_ELF_Binary_class(py::module& m) {
         "Check if the given library name exists in the current binary",
         "library_name"_a)
 
+    .def("remove_library",
+        &Binary::remove_library,
+        "Remove the given library",
+        "library_name"_a)
+
     .def("get_library",
         static_cast<no_const_func<DynamicEntryLibrary&, const std::string&>>(&Binary::get_library),
         "Return the " RST_CLASS_REF(lief.ELF.DynamicEntryLibrary) " with the given ``name``",
@@ -350,6 +365,9 @@ void init_ELF_Binary_class(py::module& m) {
 
     .def(py::self += DynamicEntry())
 
+    .def(py::self -= DynamicEntry())
+    .def(py::self -= DYNAMIC_TAGS())
+
     .def("__getitem__",
         static_cast<Segment& (Binary::*)(SEGMENT_TYPES)>(&Binary::operator[]),
         "",

include/LIEF/ELF/Binary.hpp

@@ -101,8 +101,15 @@ class DLL_PUBLIC Binary : public LIEF::Binary {
     it_dynamic_entries                     dynamic_entries(void);
     it_const_dynamic_entries               dynamic_entries(void) const;
 
+    //! @brief Add the given dynamic entry and return the entry added
     DynamicEntry&                          add(const DynamicEntry& entry);
 
+    //! @brief Remove the given dynamic entry
+    void                                   remove(const DynamicEntry& entry);
+
+    //! @brief Remove **all** dynamic entries with the given tag
+    void                                   remove(DYNAMIC_TAGS tag);
+
     //! @brief Return binary's dynamic symbols
     it_symbols                             dynamic_symbols(void);
     it_const_symbols                       dynamic_symbols(void) const;
@@ -257,6 +264,9 @@ class DLL_PUBLIC Binary : public LIEF::Binary {
     //! @brief Add a library as dependency
     DynamicEntryLibrary& add_library(const std::string& library_name);
 
+    //! @brief Remove the given library
+    void remove_library(const std::string& library_name);
+
     //! @brief Get the library object (DynamicEntryLibrary) from the given name
     DynamicEntryLibrary& get_library(const std::string& library_name);
 
@@ -404,6 +414,9 @@ class DLL_PUBLIC Binary : public LIEF::Binary {
     Binary& operator+=(const Section& section);
     Binary& operator+=(const Segment& segment);
 
+    Binary& operator-=(const DynamicEntry& entry);
+    Binary& operator-=(DYNAMIC_TAGS tag);
+
     Segment&       operator[](SEGMENT_TYPES type);
     const Segment& operator[](SEGMENT_TYPES type) const;
 

src/ELF/Binary.cpp

@@ -137,11 +137,11 @@ std::vector<std::string> Binary::get_abstract_imported_libraries(void) const {
 // ===============
 
 it_dynamic_entries Binary::dynamic_entries(void) {
-  return it_dynamic_entries{std::ref(this->dynamic_entries_)};
+  return this->dynamic_entries_;
 }
 
 it_const_dynamic_entries Binary::dynamic_entries(void) const {
-  return it_const_dynamic_entries{std::cref(this->dynamic_entries_)};
+  return this->dynamic_entries_;
 }
 
 
@@ -211,6 +211,38 @@ DynamicEntry& Binary::add(const DynamicEntry& entry) {
 
 }
 
+
+void Binary::remove(const DynamicEntry& entry) {
+  auto&& it_entry = std::find_if(
+      std::begin(this->dynamic_entries_),
+      std::end(this->dynamic_entries_),
+      [&entry] (const DynamicEntry* e) {
+        return *e == entry;
+      });
+
+  if (it_entry == std::end(this->dynamic_entries_)) {
+    std::stringstream ss;
+    ss << entry;
+    throw not_found("Can't find '" + ss.str() +  "' in the dynamic table!");
+  }
+
+  delete *it_entry;
+  this->dynamic_entries_.erase(it_entry);
+}
+
+
+void Binary::remove(DYNAMIC_TAGS tag) {
+  for (auto&& it = std::begin(this->dynamic_entries_);
+              it != std::end(this->dynamic_entries_);) {
+    if ((*it)->tag() == tag) {
+      delete *it;
+      it = this->dynamic_entries_.erase(it);
+    } else {
+      ++it;
+    }
+  }
+}
+
 // Symbols
 // =======
 
@@ -1606,6 +1638,11 @@ DynamicEntryLibrary& Binary::add_library(const std::string& library_name) {
 }
 
 
+void Binary::remove_library(const std::string& library_name) {
+  this->remove(this->get_library(library_name));
+}
+
+
 DynamicEntryLibrary& Binary::get_library(const std::string& library_name) {
   return const_cast<DynamicEntryLibrary&>(static_cast<const Binary*>(this)->get_library(library_name));
 }
@@ -1636,7 +1673,8 @@ bool Binary::has_library(const std::string& name) const {
   return it_needed != std::end(this->dynamic_entries_);
 }
 
-
+// Operator+=
+// ==========
 Binary& Binary::operator+=(const DynamicEntry& entry) {
   this->add(entry);
   return *this;
@@ -1652,7 +1690,20 @@ Binary& Binary::operator+=(const Segment& segment) {
   return *this;
 }
 
+// Operator -=
+// ===========
+Binary& Binary::operator-=(const DynamicEntry& entry) {
+  this->remove(entry);
+  return *this;
+}
+
+Binary& Binary::operator-=(DYNAMIC_TAGS tag) {
+  this->remove(tag);
+  return *this;
+}
 
+// Operator[]
+// ==========
 Segment& Binary::operator[](SEGMENT_TYPES type) {
   return this->get(type);
 }

src/ELF/DynamicEntry.cpp

@@ -90,7 +90,7 @@ void DynamicEntry::array(const std::vector<uint64_t>&) {
 }
 
 void DynamicEntry::accept(Visitor& visitor) const {
-  visitor.visit(*this); // Double dispatch to avoid down-casting
+  visitor(*this); // Double dispatch to avoid down-casting
   visitor.visit(this->value());
   visitor.visit(this->tag());
 }

tests/elf/test_dynamic.py

@@ -123,12 +123,41 @@ def remove(self):
         if os.path.isdir(self.directory):
             shutil.rmtree(self.directory)
 
+    def __del__(self):
+        self.remove()
+
 
 class TestDynamic(TestCase):
     def setUp(self):
         self.logger = logging.getLogger(__name__)
 
 
+    def test_remove_library(self):
+        sample = LibAddSample()
+        libadd = lief.parse(sample.libadd)
+        binadd = lief.parse(sample.binadd)
+
+        libadd_needed = binadd.get_library("libadd.so")
+        binadd -= libadd_needed
+        self.assertFalse(binadd.has_library("libadd.so"))
+
+
+    def test_remove_tag(self):
+        sample = LibAddSample()
+        libadd = lief.parse(sample.libadd)
+        binadd = lief.parse(sample.binadd)
+        self.logger.debug("BEFORE")
+        list(map(lambda e : self.logger.debug(e), binadd.dynamic_entries))
+        self.logger.debug("")
+        binadd -= lief.ELF.DYNAMIC_TAGS.NEEDED
+
+        self.logger.debug("AFTER")
+        list(map(lambda e : self.logger.debug(e), binadd.dynamic_entries))
+        self.logger.debug("")
+
+        self.assertTrue(all(e.tag != lief.ELF.DYNAMIC_TAGS.NEEDED for e in binadd.dynamic_entries))
+
+
     @unittest.skipUnless(sys.platform.startswith("linux"), "requires Linux")
     def test_change_libname(self):
         sample = LibAddSample()