add custom prefix to autogenerated C functions (#268)

Author: qmuntal

cmd/mkcgo/generate.go

@@ -19,9 +19,6 @@ func generateGo(src *mkcgo.Source, w io.Writer) {
 	// This block outputs C header includes and forward declarations for loader functions.
 	fmt.Fprintf(w, "/*\n")
 	fmt.Fprintf(w, "#cgo CFLAGS: -Wno-attributes\n\n")
-	for _, file := range src.Files {
-		fmt.Fprintf(w, "#include %q\n", file)
-	}
 	if *includeHeader != "" {
 		fmt.Fprintf(w, "#include \"%s\"\n", *includeHeader)
 	}
@@ -39,10 +36,10 @@ func generateGo(src *mkcgo.Source, w io.Writer) {
 	// Generate Go wrapper functions that load and unload the C symbols.
 	for _, tag := range src.Tags() {
 		fmt.Fprintf(w, "func mkcgoLoad_%s(handle unsafe.Pointer) {\n", tag)
-		fmt.Fprintf(w, "\tC.__mkcgoLoad_%s(handle)\n", tag)
+		fmt.Fprintf(w, "\tC.__mkcgo_load_%s(handle)\n", tag)
 		fmt.Fprintf(w, "}\n\n")
 		fmt.Fprintf(w, "func mkcgoUnload_%s() {\n", tag)
-		fmt.Fprintf(w, "\tC.__mkcgoUnload_%s()\n", tag)
+		fmt.Fprintf(w, "\tC.__mkcgo_unload_%s()\n", tag)
 		fmt.Fprintf(w, "}\n\n")
 	}
 
@@ -57,14 +54,13 @@ func generateGo(src *mkcgo.Source, w io.Writer) {
 
 	// Generate function wrappers.
 	for _, fn := range src.Funcs {
-		if fn.Variadic() {
-			// cgo doesn't support variadic functions
+		if !fnCalledFromGo(fn) {
 			continue
 		}
 		if fn.Optional {
 			// Generate a function that returns true if the function is available.
-			fmt.Fprintf(w, "func %s_Available() bool {\n", fn.GoName)
-			fmt.Fprintf(w, "\treturn C.%s_Available() != 0\n", fn.ImportName)
+			fmt.Fprintf(w, "func %s() bool {\n", fnGoNameAvailable(fn))
+			fmt.Fprintf(w, "\treturn C.%s() != 0\n", fnCNameAvailable(fn))
 			fmt.Fprintf(w, "}\n\n")
 		}
 		generateGoFn(fn, w)
@@ -81,10 +77,7 @@ func generateGo124(src *mkcgo.Source, w io.Writer) {
 	// This block outputs C header includes and forward declarations for loader functions.
 	fmt.Fprintf(w, "/*\n")
 	for _, fn := range src.Funcs {
-		name := fn.CName
-		if fnNeedErrWrapper(fn) {
-			name = fnCErrWrapperName(fn)
-		}
+		name := fnCName(fn)
 		if fn.NoEscape {
 			fmt.Fprintf(w, "#cgo noescape %s\n", name)
 		}
@@ -155,13 +148,26 @@ func generateCHeader(src *mkcgo.Source, w io.Writer) {
 	fmt.Fprintf(w, "#ifndef MKCGO_H // only include this header once\n")
 	fmt.Fprintf(w, "#define MKCGO_H\n\n")
 
-	for _, file := range src.Files {
-		fmt.Fprintf(w, "#include %q\n", file)
-	}
 	if *includeHeader != "" {
-		fmt.Fprintf(w, "#include \"%s\"\n", *includeHeader)
+		fmt.Fprintf(w, "#include %q\n\n", *includeHeader)
+	}
+
+	// Source includes.
+	for _, v := range src.Includes {
+		fmt.Fprintf(w, "#include %s\n", v)
+	}
+	fmt.Fprintf(w, "\n")
+
+	// Source types and enums.
+	for _, def := range src.TypeDefs {
+		fmt.Fprintf(w, "typedef %s %s;\n", def.Type, def.Name)
 	}
 	fmt.Fprintf(w, "\n")
+	fmt.Fprintf(w, "enum {\n")
+	for _, enum := range src.Enums {
+		fmt.Fprintf(w, "\t%s = %s,\n", enum.Name, enum.Value)
+	}
+	fmt.Fprintf(w, "};\n\n")
 
 	// Custom types
 	fmt.Fprintf(w, "typedef void* %s;\n", mkcgoErrState)
@@ -171,25 +177,30 @@ func generateCHeader(src *mkcgo.Source, w io.Writer) {
 
 	// Add forward declarations for loader functions.
 	for _, tag := range src.Tags() {
-		fmt.Fprintf(w, "void __mkcgoLoad_%s(void* handle);\n", tag)
-		fmt.Fprintf(w, "void __mkcgoUnload_%s();\n", tag)
+		fmt.Fprintf(w, "void __mkcgo_load_%s(void* handle);\n", tag)
+		fmt.Fprintf(w, "void __mkcgo_unload_%s();\n", tag)
 	}
 	fmt.Fprintf(w, "\n")
 
 	// Add forward declarations for optional functions.
 	for _, fn := range src.Funcs {
 		if fn.Optional {
-			fmt.Fprintf(w, "int %s_Available();\n", fn.ImportName)
+			fmt.Fprintf(w, "int %s();\n", fnCNameAvailable(fn))
 		}
 	}
 	fmt.Fprintf(w, "\n")
 
 	// Add forward declarations for function wrappers returning errors.
 	for _, fn := range src.Funcs {
-		if !fnNeedErrWrapper(fn) {
+		if !fnCalledFromGo(fn) {
+			// cgo doesn't support variadic functions, no need to include them.
 			continue
 		}
-		fmt.Fprintf(w, "%s %s(%s);\n", fn.Ret.Type, fnCErrWrapperName(fn), fnCErrWrapperParams(fn, false))
+		if fnNeedErrWrapper(fn) {
+			fmt.Fprintf(w, "%s %s(%s);\n", fn.Ret.Type, fnCName(fn), fnCErrWrapperParams(fn, false))
+		} else {
+			fmt.Fprintf(w, "%s %s(%s);\n", fn.Ret.Type, fnCName(fn), fnToCArgs(fn, true, false))
+		}
 	}
 	fmt.Fprintf(w, "\n")
 	fmt.Fprintf(w, "#endif // MKCGO_H\n")
@@ -204,11 +215,8 @@ func generateC(src *mkcgo.Source, w io.Writer) {
 	fmt.Fprintf(w, "#include <stdlib.h>\n")
 	fmt.Fprintf(w, "#include <stdint.h>\n")
 	fmt.Fprintf(w, "#include <stdio.h>\n")
-	for _, file := range src.Files {
-		fmt.Fprintf(w, "#include %q\n", file)
-	}
 	if *includeHeader != "" {
-		fmt.Fprintf(w, "#include \"%s\"\n", *includeHeader)
+		fmt.Fprintf(w, "#include %q\n", *includeHeader)
 	}
 	fmt.Fprintf(w, "#include \"%s\"\n", autogeneratedFileName(".h"))
 	fmt.Fprintf(w, "\n")
@@ -222,12 +230,11 @@ func generateC(src *mkcgo.Source, w io.Writer) {
 	fmt.Fprintf(w, "#endif\n\n")
 
 	// Function pointer declarations.
-	fmt.Fprintf(w, "#define __mkcgo__funcptr(name) typeof(name) *_g_##name;\n\n")
 	for _, fn := range src.Funcs {
 		if fn.VariadicInst {
 			continue
 		}
-		fmt.Fprintf(w, "__mkcgo__funcptr(%s);\n", fn.ImportName)
+		fmt.Fprintf(w, "%s (*_g_%s)(%s);\n", fn.Ret.Type, fn.ImportName, fnToCArgs(fn, true, false))
 	}
 	fmt.Fprintf(w, "\n")
 
@@ -242,7 +249,7 @@ func generateC(src *mkcgo.Source, w io.Writer) {
 
 	// Loader and unloader functions for each tag.
 	for _, tag := range src.Tags() {
-		fmt.Fprintf(w, "void __mkcgoLoad_%s(void* handle) {\n", tag)
+		fmt.Fprintf(w, "void __mkcgo_load_%s(void* handle) {\n", tag)
 		for _, fn := range src.Funcs {
 			if fn.VariadicInst {
 				continue
@@ -267,7 +274,7 @@ func generateC(src *mkcgo.Source, w io.Writer) {
 		}
 		fmt.Fprintf(w, "}\n\n")
 
-		fmt.Fprintf(w, "void __mkcgoUnload_%s() {\n", tag)
+		fmt.Fprintf(w, "void __mkcgo_unload_%s() {\n", tag)
 		for _, fn := range src.Funcs {
 			if fn.VariadicInst {
 				continue
@@ -292,26 +299,25 @@ func generateC(src *mkcgo.Source, w io.Writer) {
 		typedefs[def.Name] = def.Type
 	}
 	for _, fn := range src.Funcs {
-		if fn.Variadic() {
-			// cgo doesn't support variadic functions
+		if !fnCalledFromGo(fn) {
+			// cgo doesn't support variadic functions, no need to include them.
 			continue
 		}
 		if fn.Optional {
 			// Generate a function that returns true if the function is available.
-			fmt.Fprintf(w, "int %s_Available() {\n", fn.CName)
+			fmt.Fprintf(w, "int %s() {\n", fnCNameAvailable(fn))
 			fmt.Fprintf(w, "\treturn _g_%s != NULL;\n", fn.ImportName)
 			fmt.Fprintf(w, "}\n\n")
 		}
-		generateCFn(fn, w)
-		generateCFnErrorWrapper(typedefs, fn, w)
+		generateCFn(typedefs, fn, w)
 	}
 }
 
 // generateGoFn generates Go function f.
 func generateGoFn(fn *mkcgo.Func, w io.Writer) {
-	fnCall := fmt.Sprintf("C.%s(%s)", fn.CName, fnToGoArgs(fn))
+	fnCall := fmt.Sprintf("C.%s(%s)", fnCName(fn), fnToGoArgs(fn))
 	// Function definition
-	fmt.Fprintf(w, "func %s(%s)", fn.GoName, fnToGoParams(fn))
+	fmt.Fprintf(w, "func %s(%s)", fnGoName(fn), fnToGoParams(fn))
 	if retIsVoid(fn.Ret) {
 		// Easy path, just call the C function. No need to write the return types,
 		// nor do error handling, nor cast the return value.
@@ -320,17 +326,16 @@ func generateGoFn(fn *mkcgo.Func, w io.Writer) {
 		fmt.Fprintf(w, "}\n\n")
 		return
 	}
-	typ, _ := cTypeToGo(fn.Ret.Type, false)
+	goType, needCast := cTypeToGo(fn.Ret.Type, false)
 	if fn.NoError {
-		fmt.Fprintf(w, " %s ", typ)
+		fmt.Fprintf(w, " %s ", goType)
 	} else {
-		fmt.Fprintf(w, " (%s, error) ", typ)
+		fmt.Fprintf(w, " (%s, error) ", goType)
 	}
 	fmt.Fprintf(w, "{\n")
 
 	// Function call
 	var needUnsafeCast bool
-	goType, needCast := cTypeToGo(fn.Ret.Type, false)
 	if needCast && goType[0] == '*' {
 		goType = fmt.Sprintf("(%s)(unsafe.Pointer", goType)
 		needUnsafeCast = true
@@ -351,7 +356,7 @@ func generateGoFn(fn *mkcgo.Func, w io.Writer) {
 		return
 	}
 	fmt.Fprintf(w, "\tvar _err C.%s\n", mkcgoErrState)
-	fmt.Fprintf(w, "\t_ret := C.%s(", fnCErrWrapperName(fn))
+	fmt.Fprintf(w, "\t_ret := C.%s(", fnCName(fn))
 	args := fnToGoArgs(fn)
 	if len(args) > 0 {
 		args += ", "
@@ -368,26 +373,22 @@ func generateGoFn(fn *mkcgo.Func, w io.Writer) {
 	} else {
 		fmt.Fprintf(w, "_ret")
 	}
-	fmt.Fprintf(w, ", newMkcgoErr(%q, _err)\n", fn.CName)
-	fmt.Fprintf(w, "}\n\n")
-}
-
-func generateCFn(fn *mkcgo.Func, w io.Writer) {
-	fmt.Fprintf(w, "%s %s(%s) {\n\t", fn.Ret.Type, fn.CName, fnToCArgs(fn, true, true))
-	if !retIsVoid(fn.Ret) {
-		fmt.Fprintf(w, "return ")
-	}
-	fmt.Fprintf(w, "_g_%s(%s);\n", fn.ImportName, fnToCArgs(fn, false, true))
+	fmt.Fprintf(w, ", newMkcgoErr(%q, _err)\n", fn.Name)
 	fmt.Fprintf(w, "}\n\n")
 }
 
-// generateCFnErrorWrapper generates C function wrapper for function f
-// that returns an error state.
-func generateCFnErrorWrapper(typedefs map[string]string, fn *mkcgo.Func, w io.Writer) {
+func generateCFn(typedefs map[string]string, fn *mkcgo.Func, w io.Writer) {
 	if !fnNeedErrWrapper(fn) {
+		fmt.Fprintf(w, "%s %s(%s) {\n\t", fn.Ret.Type, fnCName(fn), fnToCArgs(fn, true, true))
+		if !retIsVoid(fn.Ret) {
+			fmt.Fprintf(w, "return ")
+		}
+		fmt.Fprintf(w, "_g_%s(%s);\n", fn.ImportName, fnToCArgs(fn, false, true))
+		fmt.Fprintf(w, "}\n\n")
 		return
 	}
-	fmt.Fprintf(w, "%s %s(%s) {\n", fn.Ret.Type, fnCErrWrapperName(fn), fnCErrWrapperParams(fn, true))
+
+	fmt.Fprintf(w, "%s %s(%s) {\n", fn.Ret.Type, fnCName(fn), fnCErrWrapperParams(fn, true))
 	fmt.Fprintf(w, "\tmkcgo_err_clear();\n") // clear any previous error
 	fmt.Fprintf(w, "\t%s _ret = _g_%s(%s);\n", fn.Ret.Type, fn.ImportName, fnToCArgs(fn, false, true))
 	errCond := "<= 0"
@@ -506,7 +507,7 @@ func cTypeToGo(t string, cgo bool) (string, bool) {
 // paramToC returns C source code of parameter p.
 func paramToC(i int, p *mkcgo.Param, addType, addName bool) string {
 	if p.Type == "..." {
-		return ""
+		return "..."
 	}
 	var s string
 	if addType {
@@ -585,12 +586,33 @@ func fnCErrWrapperParams(fn *mkcgo.Func, addName bool) string {
 	return args
 }
 
-// fnCErrWrapperName returns the name of the error wrapper function for function f.
-func fnCErrWrapperName(fn *mkcgo.Func) string {
-	return "_mkcgo_err_" + fn.CName
+// fnGoName returns the Go function name for function f.
+func fnGoName(fn *mkcgo.Func) string {
+	// TODO: use a prefix that is not OpenSSL specific.
+	return "go_openssl_" + fn.Name
+}
+
+func fnGoNameAvailable(fn *mkcgo.Func) string {
+	return fnGoName(fn) + "_Available"
+}
+
+// fnCName returns the C function name for function f.
+func fnCName(fn *mkcgo.Func) string {
+	return "_mkcgo_" + fn.Name
+}
+
+// fnCNameAvailable returns the C function name for function f
+// that checks if the function is available.
+func fnCNameAvailable(fn *mkcgo.Func) string {
+	return "_mkcgo_available_" + fn.Name
 }
 
 // fnNeedErrWrapper reports whether function fn needs an error wrapper.
 func fnNeedErrWrapper(fn *mkcgo.Func) bool {
 	return !fn.NoError && !retIsVoid(fn.Ret)
 }
+
+// fnCalledFromGo reports whether function fn is called from Go code.
+func fnCalledFromGo(fn *mkcgo.Func) bool {
+	return !fn.Variadic() // cgo doesn't support variadic functions
+}

errors.go

@@ -5,7 +5,6 @@ package openssl
 /*
 #include <stdlib.h> // for calloc and free
 #include <string.h> // for strdup
-#include "shims.h"
 #include "zossl.h"
 
 // OpenSSL only allows a maximum of 16 errors to be stored in the error queue.
@@ -22,7 +21,7 @@ typedef struct ossl_err_state_st {
 // mkcgo_err_clear clears the error queue in OpenSSL.
 void mkcgo_err_clear() {
 	// Clear the error queue.
-	ERR_clear_error();
+	_mkcgo_ERR_clear_error();
 }
 
 // mkcgo_err_retrieve retrieves the error state from OpenSSL.
@@ -37,12 +36,12 @@ mkcgo_err_state mkcgo_err_retrieve() {
 	// Retrieve the errors from OpenSSL.
 	for (int i = 0; i < ERR_NUM_MAX; i++) {
 		const char *file;
-		if (OPENSSL_version_major_Available() == 1) { // Only available in OpenSSL 3.
+		if (_mkcgo_available_OPENSSL_version_major() == 1) { // Only available in OpenSSL 3.
 			// OpenSSL 3 error handling
-			errs->code[i] = ERR_get_error_all(&file, &errs->line[i], NULL, NULL, NULL);
+			errs->code[i] = _mkcgo_ERR_get_error_all(&file, &errs->line[i], NULL, NULL, NULL);
 		} else {
 			// OpenSSL 1 error handling
-			errs->code[i] = ERR_get_error_line(&file, &errs->line[i]);
+			errs->code[i] = _mkcgo_ERR_get_error_line(&file, &errs->line[i]);
 		}
 		if (errs->code[i] == 0) {
 			break;

hash.go

@@ -3,7 +3,6 @@
 package openssl
 
 /*
-#include "shims.h"
 #include "zossl.h"
 // go_hash_sum copies ctx into ctx2 and calls EVP_DigestFinal_ex using ctx2.
 // This is necessary because Go hash.Hash mandates that Sum has no effect
@@ -14,9 +13,9 @@ package openssl
 static inline int
 go_hash_sum(const _EVP_MD_CTX_PTR ctx, _EVP_MD_CTX_PTR ctx2, unsigned char *out, mkcgo_err_state *_err_state)
 {
-	if (_mkcgo_err_EVP_MD_CTX_copy(ctx2, ctx, _err_state) != 1)
+	if (_mkcgo_EVP_MD_CTX_copy(ctx2, ctx, _err_state) != 1)
 		return -1;
-	if (_mkcgo_err_EVP_DigestFinal_ex(ctx2, out, NULL, _err_state) <= 0)
+	if (_mkcgo_EVP_DigestFinal_ex(ctx2, out, NULL, _err_state) <= 0)
 		return -2;
 	return 1;
 }

internal/mkcgo/mkcgo.go

@@ -11,6 +11,7 @@ type Source struct {
 	Funcs    []*Func
 	Files    []string
 	Comments []string // All line comments. Directives in this slice start with "#"
+	Includes []string // All #include directives, without the #include prefix.
 }
 
 // TypeDef describes a type definition.
@@ -28,8 +29,7 @@ type Enum struct {
 // Func describes a function.
 type Func struct {
 	FuncAttributes
-	GoName string
-	CName  string
+	Name   string
 	Params []*Param
 	Ret    *Return
 }