1 files changed, 62 insertions, 0 deletions
diff --git a/libc-bottom-half/cloudlibc/src/libc/fcntl/fcntl.c b/libc-bottom-half/cloudlibc/src/libc/fcntl/fcntl.c
new file mode 100644
index 0000000..5d4055d
--- /dev/null
+++ b/libc-bottom-half/cloudlibc/src/libc/fcntl/fcntl.c
@@ -0,0 +1,62 @@
+// Copyright (c) 2015-2016 Nuxi, https://nuxi.nl/
+//
+// SPDX-License-Identifier: BSD-2-Clause
+
+#include <wasi/api.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdarg.h>
+
+int fcntl(int fildes, int cmd, ...) {
+  switch (cmd) {
+    case F_GETFD:
+      // Act as if the close-on-exec flag is always set.
+      return FD_CLOEXEC;
+    case F_SETFD:
+      // The close-on-exec flag is ignored.
+      return 0;
+    case F_GETFL: {
+      // Obtain the flags and the rights of the descriptor.
+      __wasi_fdstat_t fds;
+      __wasi_errno_t error = __wasi_fd_fdstat_get(fildes, &fds);
+      if (error != 0) {
+        errno = error;
+        return -1;
+      }
+
+      // Roughly approximate the access mode by converting the rights.
+      int oflags = fds.fs_flags;
+      if ((fds.fs_rights_base &
+           (__WASI_RIGHTS_FD_READ | __WASI_RIGHTS_FD_READDIR)) != 0) {
+        if ((fds.fs_rights_base & __WASI_RIGHTS_FD_WRITE) != 0)
+          oflags |= O_RDWR;
+        else
+          oflags |= O_RDONLY;
+      } else if ((fds.fs_rights_base & __WASI_RIGHTS_FD_WRITE) != 0) {
+        oflags |= O_WRONLY;
+      } else {
+        oflags |= O_SEARCH;
+      }
+      return oflags;
+    }
+    case F_SETFL: {
+      // Set new file descriptor flags.
+      va_list ap;
+      va_start(ap, cmd);
+      int flags = va_arg(ap, int);
+      va_end(ap);
+
+      __wasi_fdflags_t fs_flags = flags & 0xfff;
+      __wasi_errno_t error =
+          __wasi_fd_fdstat_set_flags(fildes, fs_flags);
+      if (error != 0) {
+        errno = error;
+        return -1;
+      }
+      return 0;
+    }
+    default:
+      errno = EINVAL;
+      return -1;
+  }
+}