syscall: libc_wasip2: add fdopendir/readdir/closedir

src/syscall/libc_wasip2.go

@@ -848,23 +848,120 @@ func errorCodeToErrno(err types.ErrorCode) Errno {
  return Errno(err)
 }
 
+type libc_DIR struct {
+ d types.DirectoryEntryStream
+}
+
 // DIR *fdopendir(int);
 //
 //go:export fdopendir
 func fdopendir(fd int32) unsafe.Pointer {
- return nil
+ if _, ok := wasiStreams[fd]; ok {
+ libcErrno = EBADF
+ return nil
+ }
+
+ stream, ok := wasiFiles[fd]
+ if !ok {
+ libcErrno = EBADF
+ return nil
+ }
+ if stream.d == cm.ResourceNone {
+ libcErrno = EBADF
+ return nil
+ }
+
+ result := stream.d.ReadDirectory()
+ if err := result.Err(); err != nil {
+ libcErrno = errorCodeToErrno(*err)
+ return nil
+ }
+
+ return unsafe.Pointer(&libc_DIR{d: *result.OK()})
 }
 
 // int fdclosedir(DIR *);
 //
 //go:export fdclosedir
-func fdclosedir(unsafe.Pointer) int32 {
+func fdclosedir(dirp unsafe.Pointer) int32 {
+ if dirp == nil {
+ return 0
+
+ }
+ dir := (*libc_DIR)(dirp)
+ if dir.d == cm.ResourceNone {
+ return 0
+ }
+
+ dir.d.ResourceDrop()
+ dir.d = cm.ResourceNone
+
  return 0
 }
 
 // struct dirent *readdir(DIR *);
 //
 //go:export readdir
-func readdir(unsafe.Pointer) *Dirent {
- return nil
+func readdir(dirp unsafe.Pointer) *Dirent {
+ if dirp == nil {
+ return nil
+
+ }
+ dir := (*libc_DIR)(dirp)
+ if dir.d == cm.ResourceNone {
+ return nil
+ }
+
+ result := dir.d.ReadDirectoryEntry()
+ if err := result.Err(); err != nil {
+ libcErrno = errorCodeToErrno(*err)
+ return nil
+ }
+
+ entry := result.OK().Some()
+ if entry == nil {
+ libcErrno = 0
+ return nil
+ }
+
+ // The dirent C struct uses a flexible array member to indicate that the
+ // directory name is laid out in memory right after the struct data:
+ //
+ // struct dirent {
+ // ino_t d_ino;
+ // unsigned char d_type;
+ // char d_name[];
+ // };
+ buf := make([]byte, unsafe.Sizeof(Dirent{})+uintptr(len(entry.Name)))
+ dirent := (*Dirent)((unsafe.Pointer)(&buf[0]))
+
+ // No inodes in wasi
+ dirent.Ino = 0
+ dirent.Type = p2fileTypeToLibcType(entry.Type)
+ copy(buf[unsafe.Offsetof(dirent.Type)+1:], entry.Name)
+
+ return dirent
+}
+
+func p2fileTypeToLibcType(t types.DescriptorType) uint8 {
+ switch t {
+ case types.DescriptorTypeUnknown:
+ return DT_UNKNOWN
+ case types.DescriptorTypeBlockDevice:
+ return DT_BLK
+ case types.DescriptorTypeCharacterDevice:
+ return DT_CHR
+ case types.DescriptorTypeDirectory:
+ return DT_DIR
+ case types.DescriptorTypeFIFO:
+ return DT_FIFO
+ case types.DescriptorTypeSymbolicLink:
+ return DT_LNK
+ case types.DescriptorTypeRegularFile:
+ return DT_REG
+ case types.DescriptorTypeSocket:
+ return DT_FIFO
+ }
+
+ return DT_UNKNOWN
 }