diff options
Diffstat (limited to 'cgo/cgo.go')
| -rw-r--r-- | cgo/cgo.go | 121 |
1 files changed, 117 insertions, 4 deletions
diff --git a/cgo/cgo.go b/cgo/cgo.go index a90b30753..0ed26e3fb 100644 --- a/cgo/cgo.go +++ b/cgo/cgo.go @@ -138,7 +138,8 @@ typedef unsigned long long _Cgo_ulonglong; // first. // These functions will be modified to get a "C." prefix, so the source below // doesn't reflect the final AST. -const generatedGoFilePrefix = ` +const generatedGoFilePrefixBase = ` +import "syscall" import "unsafe" var _ unsafe.Pointer @@ -169,6 +170,74 @@ func __CBytes([]byte) unsafe.Pointer func CBytes(b []byte) unsafe.Pointer { return C.__CBytes(b) } + +//go:linkname C.__get_errno_num runtime.cgo_errno +func __get_errno_num() uintptr +` + +const generatedGoFilePrefixOther = generatedGoFilePrefixBase + ` +func __get_errno() error { + return syscall.Errno(C.__get_errno_num()) +} +` + +// Windows uses fake errno values in the syscall package. +// See for example: https://github.com/golang/go/issues/23468 +// TinyGo uses mingw-w64 though, which does have defined errno values. Since the +// syscall package is the standard library one we can't change it, but we can +// map the errno values to match the values in the syscall package. +// Source of the errno values: lib/mingw-w64/mingw-w64-headers/crt/errno.h +const generatedGoFilePrefixWindows = generatedGoFilePrefixBase + ` +var __errno_mapping = [...]syscall.Errno{ + 1: syscall.EPERM, + 2: syscall.ENOENT, + 3: syscall.ESRCH, + 4: syscall.EINTR, + 5: syscall.EIO, + 6: syscall.ENXIO, + 7: syscall.E2BIG, + 8: syscall.ENOEXEC, + 9: syscall.EBADF, + 10: syscall.ECHILD, + 11: syscall.EAGAIN, + 12: syscall.ENOMEM, + 13: syscall.EACCES, + 14: syscall.EFAULT, + 16: syscall.EBUSY, + 17: syscall.EEXIST, + 18: syscall.EXDEV, + 19: syscall.ENODEV, + 20: syscall.ENOTDIR, + 21: syscall.EISDIR, + 22: syscall.EINVAL, + 23: syscall.ENFILE, + 24: syscall.EMFILE, + 25: syscall.ENOTTY, + 27: syscall.EFBIG, + 28: syscall.ENOSPC, + 29: syscall.ESPIPE, + 30: syscall.EROFS, + 31: syscall.EMLINK, + 32: syscall.EPIPE, + 33: syscall.EDOM, + 34: syscall.ERANGE, + 36: syscall.EDEADLK, + 38: syscall.ENAMETOOLONG, + 39: syscall.ENOLCK, + 40: syscall.ENOSYS, + 41: syscall.ENOTEMPTY, + 42: syscall.EILSEQ, +} + +func __get_errno() error { + num := C.__get_errno_num() + if num < uintptr(len(__errno_mapping)) { + if mapped := __errno_mapping[num]; mapped != 0 { + return mapped + } + } + return syscall.Errno(num) +} ` // Process extracts `import "C"` statements from the AST, parses the comment @@ -178,7 +247,7 @@ func CBytes(b []byte) unsafe.Pointer { // functions), the CFLAGS and LDFLAGS found in #cgo lines, and a map of file // hashes of the accessed C header files. If there is one or more error, it // returns these in the []error slice but still modifies the AST. -func Process(files []*ast.File, dir, importPath string, fset *token.FileSet, cflags []string) ([]*ast.File, []string, []string, []string, map[string][]byte, []error) { +func Process(files []*ast.File, dir, importPath string, fset *token.FileSet, cflags []string, goos string) ([]*ast.File, []string, []string, []string, map[string][]byte, []error) { p := &cgoPackage{ packageName: files[0].Name.Name, currentDir: dir, @@ -210,7 +279,12 @@ func Process(files []*ast.File, dir, importPath string, fset *token.FileSet, cfl // Construct a new in-memory AST for CGo declarations of this package. // The first part is written as Go code that is then parsed, but more code // is added later to the AST to declare functions, globals, etc. - goCode := "package " + files[0].Name.Name + "\n\n" + generatedGoFilePrefix + goCode := "package " + files[0].Name.Name + "\n\n" + if goos == "windows" { + goCode += generatedGoFilePrefixWindows + } else { + goCode += generatedGoFilePrefixOther + } p.generated, err = parser.ParseFile(fset, dir+"/!cgo.go", goCode, parser.ParseComments) if err != nil { // This is always a bug in the cgo package. @@ -225,7 +299,7 @@ func Process(files []*ast.File, dir, importPath string, fset *token.FileSet, cfl switch decl := decl.(type) { case *ast.FuncDecl: switch decl.Name.Name { - case "CString", "GoString", "GoStringN", "__GoStringN", "GoBytes", "__GoBytes", "CBytes", "__CBytes": + case "CString", "GoString", "GoStringN", "__GoStringN", "GoBytes", "__GoBytes", "CBytes", "__CBytes", "__get_errno_num", "__get_errno", "__errno_mapping": // Adjust the name to have a "C." prefix so it is correctly // resolved. decl.Name.Name = "C." + decl.Name.Name @@ -1279,6 +1353,45 @@ extern __typeof(%s) %s __attribute__((alias(%#v))); // separate namespace (no _Cgo_ hacks like in gc). func (f *cgoFile) walker(cursor *astutil.Cursor, names map[string]clangCursor) bool { switch node := cursor.Node().(type) { + case *ast.AssignStmt: + // An assign statement could be something like this: + // + // val, errno := C.some_func() + // + // Check whether it looks like that, and if so, read the errno value and + // return it as the second return value. The call will be transformed + // into something like this: + // + // val, errno := C.some_func(), C.__get_errno() + if len(node.Lhs) != 2 || len(node.Rhs) != 1 { + return true + } + rhs, ok := node.Rhs[0].(*ast.CallExpr) + if !ok { + return true + } + fun, ok := rhs.Fun.(*ast.SelectorExpr) + if !ok { + return true + } + x, ok := fun.X.(*ast.Ident) + if !ok { + return true + } + if found, ok := names[fun.Sel.Name]; ok && x.Name == "C" { + // Replace "C"."some_func" into "C.somefunc". + rhs.Fun = &ast.Ident{ + NamePos: x.NamePos, + Name: f.getASTDeclName(fun.Sel.Name, found, true), + } + // Add the errno value as the second value in the statement. + node.Rhs = append(node.Rhs, &ast.CallExpr{ + Fun: &ast.Ident{ + NamePos: node.Lhs[1].End(), + Name: "C.__get_errno", + }, + }) + } case *ast.CallExpr: fun, ok := node.Fun.(*ast.SelectorExpr) if !ok { |