Fix std::remove on folders #4440

Author: Piotr.Paczkowski

src/library_fs.js

@@ -795,8 +795,9 @@ mergeInto(LibraryManager.library, {
       var node = FS.lookupNode(parent, name);
       var err = FS.mayDelete(parent, name, false);
       if (err) {
-        // POSIX says unlink should set EPERM, not EISDIR
-        if (err === ERRNO_CODES.EISDIR) err = ERRNO_CODES.EPERM;
+        // According to POSIX, we should map EISDIR to EPERM, but
+        // we instead do what Linux does (and we must, as we use
+        // the musl linux libc).
         throw new FS.ErrnoError(err);
       }
       if (!parent.node_ops.unlink) {

tests/cstdio/test_remove.cpp

@@ -0,0 +1,63 @@
+#include <assert.h>
+#include <errno.h>
+#include <cstdio>
+#include <iostream>
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+
+void create_file(const char *path, const char *buffer, int mode) {
+  int fd = open(path, O_WRONLY | O_CREAT | O_EXCL, mode);
+  assert(fd >= 0);
+
+  int err = write(fd, buffer, sizeof(char) * strlen(buffer));
+  assert(err ==  (sizeof(char) * strlen(buffer)));
+
+  close(fd);
+}
+
+void setup() {
+  create_file("file", "abcdef", 0777);
+  mkdir("dir", 0777);
+  create_file("dir/file", "abcdef", 0777);
+  mkdir("dir/subdir", 0777);
+}
+
+void cleanup() {
+  // make sure we get it all regardless of anything failing
+  unlink("file");
+  unlink("dir/file");
+  rmdir("dir/subdir");
+  rmdir("dir");
+}
+
+void test() {
+  int err;
+  
+  err = std::remove("dir/file");
+  assert(!err);
+
+  err = std::remove("file");
+  assert(!err);
+
+  // should fail, folder is not empty
+  err = std::remove("dir");
+  assert(err);
+
+  err = std::remove("dir/subdir");
+  assert(!err);
+
+  err = std::remove("dir");
+  assert(!err);
+
+  std::cout << "success";
+}
+
+int main() {
+  atexit(cleanup);
+  setup();
+  test();
+  return EXIT_SUCCESS;
+}

tests/test_core.py

@@ -1786,6 +1786,10 @@ def test_rename(self):
     src = open(path_from_root('tests', 'stdio', 'test_rename.c'), 'r').read()
     self.do_run(src, 'success', force_c=True)
 
+  def test_remove(self):
+    src = open(path_from_root('tests', 'cstdio', 'test_remove.cpp'), 'r').read()
+    self.do_run(src, 'success')
+
   def test_alloca_stack(self):
     test_path = path_from_root('tests', 'core', 'test_alloca_stack')
     src, output = (test_path + s for s in ('.in', '.out'))

tests/unistd/unlink.c

@@ -79,7 +79,9 @@ void test() {
 
   err = unlink("dir-readonly");
   assert(err == -1);
-#ifdef __linux__
+
+  // emscripten uses 'musl' what is an implementation of the standard library for Linux-based systems
+#if defined(__linux__) || defined(__EMSCRIPTEN__)
   assert(errno == EISDIR);
 #else
   assert(errno == EPERM);