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Mar 20, 2025
Merged

Add custom prefix to autogenerated C functions #268

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142 changes: 82 additions & 60 deletions cmd/mkcgo/generate.go
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Original file line number Diff line number Diff line change
Expand Up @@ -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)
}
Expand All @@ -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")
}

Expand All @@ -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)
Expand All @@ -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)
}
Expand Down Expand Up @@ -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)
Expand All @@ -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")
Expand All @@ -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")
Expand All @@ -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")

Expand All @@ -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
Expand All @@ -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
Expand All @@ -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.
Expand All @@ -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
Expand All @@ -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 += ", "
Expand All @@ -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"
Expand Down Expand Up @@ -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 {
Expand Down Expand Up @@ -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.
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TODO, open an issue or fix?

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Fixed in #269 😄

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
}
9 changes: 4 additions & 5 deletions errors.go
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Original file line number Diff line number Diff line change
Expand Up @@ -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.
Expand All @@ -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.
Expand All @@ -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;
Expand Down
5 changes: 2 additions & 3 deletions hash.go
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Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand All @@ -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;
}
Expand Down
4 changes: 2 additions & 2 deletions internal/mkcgo/mkcgo.go
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Original file line number Diff line number Diff line change
Expand Up @@ -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.
Expand All @@ -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
}
Expand Down
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