Add printf key/leaf writer functionality

This extends upon the sscanf reader functionality, with the intent of
providing key/leaf pretty printing
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

src/cc/bpf_common.cc

@@ -182,4 +182,15 @@ int bpf_table_update_id(void *program, size_t id, const char *key, const char *l
   return mod->table_update(id, key, leaf);
 }
 
+int bpf_table_key_snprintf(void *program, size_t id, char *buf, size_t buflen, const void *key) {
+  auto mod = static_cast<ebpf::BPFModule *>(program);
+  if (!mod) return 0;
+  return mod->table_key_printf(id, buf, buflen, key);
+}
+int bpf_table_leaf_snprintf(void *program, size_t id, char *buf, size_t buflen, const void *leaf) {
+  auto mod = static_cast<ebpf::BPFModule *>(program);
+  if (!mod) return 0;
+  return mod->table_key_printf(id, buf, buflen, leaf);
+}
+
 }

src/cc/bpf_common.h

@@ -48,6 +48,10 @@ size_t bpf_table_key_size(void *program, const char *table_name);
 size_t bpf_table_key_size_id(void *program, size_t id);
 size_t bpf_table_leaf_size(void *program, const char *table_name);
 size_t bpf_table_leaf_size_id(void *program, size_t id);
+int bpf_table_key_snprintf(void *program, size_t id, char *buf, size_t buflen, const void *key);
+int bpf_table_leaf_snprintf(void *program, size_t id, char *buf, size_t buflen, const void *leaf);
+//int bpf_table_key_sscanf(void *program, size_t id, const char *buf, void *key);
+//int bpf_table_leaf_sscanf(void *program, size_t id, const char *buf, void *leaf);
 int bpf_table_update(void *program, const char *table_name, const char *key, const char *leaf);
 int bpf_table_update_id(void *program, size_t id, const char *key, const char *leaf);
 

src/cc/bpf_module.h

@@ -42,8 +42,9 @@ class BPFModule {
   int parse(llvm::Module *mod);
   int finalize();
   int annotate();
-  std::unique_ptr<llvm::ExecutionEngine> finalize_reader(std::unique_ptr<llvm::Module> mod);
+  std::unique_ptr<llvm::ExecutionEngine> finalize_rw(std::unique_ptr<llvm::Module> mod);
   llvm::Function * make_reader(llvm::Module *mod, llvm::Type *type);
+  llvm::Function * make_writer(llvm::Module *mod, llvm::Type *type);
   void dump_ir(llvm::Module &mod);
   int load_file_module(std::unique_ptr<llvm::Module> *mod, const std::string &file, bool in_memory);
   int load_includes(const std::string &tmpfile);
@@ -70,10 +71,12 @@ class BPFModule {
   const char * table_key_desc(const std::string &name) const;
   size_t table_key_size(size_t id) const;
   size_t table_key_size(const std::string &name) const;
+  int table_key_printf(size_t id, char *buf, size_t buflen, const void *key);
   const char * table_leaf_desc(size_t id) const;
   const char * table_leaf_desc(const std::string &name) const;
   size_t table_leaf_size(size_t id) const;
   size_t table_leaf_size(const std::string &name) const;
+  int table_leaf_printf(size_t id, char *buf, size_t buflen, const void *leaf);
   int table_update(size_t id, const char *key, const char *leaf);
   int table_update(const std::string &name, const char *key, const char *leaf);
   char * license() const;
@@ -84,7 +87,7 @@ class BPFModule {
   std::string proto_filename_;
   std::unique_ptr<llvm::LLVMContext> ctx_;
   std::unique_ptr<llvm::ExecutionEngine> engine_;
-  std::unique_ptr<llvm::ExecutionEngine> reader_engine_;
+  std::unique_ptr<llvm::ExecutionEngine> rw_engine_;
   std::unique_ptr<llvm::Module> mod_;
   std::unique_ptr<BLoader> b_loader_;
   std::unique_ptr<ClangLoader> clang_loader_;
@@ -93,6 +96,7 @@ class BPFModule {
   std::map<std::string, size_t> table_names_;
   std::vector<std::string> function_names_;
   std::map<llvm::Type *, llvm::Function *> readers_;
+  std::map<llvm::Type *, llvm::Function *> writers_;
 };
 
 }  // namespace ebpf

src/cc/table_desc.h

@@ -33,6 +33,8 @@ struct TableDesc {
   std::string leaf_desc;
   llvm::Function *key_reader;
   llvm::Function *leaf_reader;
+  llvm::Function *key_writer;
+  llvm::Function *leaf_writer;
 };
 
 }  // namespace ebpf