Cleanup symlink tests (emscripten-core#21890)

- Add some more tests to `links.c` and make sure it runs on native linux.
- Simplify symlink_on_nodefs.c by using assert.

Also, fix `utils.delete_content` so that it also removes dangling
symlinks.  Without this the dangling symlinks in the test output
directory are not removed.

.circleci/config.yml

@@ -609,7 +609,7 @@ jobs:
             wasmfs.test_stat
             wasmfs.test_fstatat
             wasmfs.test_futimens
-            wasmfs.test_unistd_links_memfs
+            wasmfs.test_unistd_links
             wasmfs.test_fcntl_open
             wasmfs.test_fs_js_api
             wasmfs.test_fs_llseek

src/library_fs.js

@@ -1014,8 +1014,8 @@ FS.staticInit();` +
         throw new FS.ErrnoError({{{ cDefs.ENOENT }}});
       }
       flags = typeof flags == 'string' ? FS_modeStringToFlags(flags) : flags;
-      mode = typeof mode == 'undefined' ? 438 /* 0666 */ : mode;
       if ((flags & {{{ cDefs.O_CREAT }}})) {
+        mode = typeof mode == 'undefined' ? 438 /* 0666 */ : mode;
         mode = (mode & {{{ cDefs.S_IALLUGO }}}) | {{{ cDefs.S_IFREG }}};
       } else {
         mode = 0;

test/test_core.py

@@ -6068,7 +6068,7 @@ def test_unistd_unlink(self, fs):
     self.do_runf('unistd/unlink.c', 'success')
 
   @parameterized({
-    'memfs': ([], False),
+    '': ([], False),
     'nodefs': (['-DNODEFS', '-lnodefs.js'], True)
   })
   def test_unistd_links(self, args, nodefs):

test/unistd/links.c

@@ -7,38 +7,32 @@
 
 #include <assert.h>
 #include <errno.h>
+#include <fcntl.h>
 #include <stdio.h>
 #include <string.h>
+#include <sys/stat.h>
 #include <unistd.h>
 
 #ifdef __EMSCRIPTEN__
 #include <emscripten.h>
-#else
-#include <sys/stat.h>
-#include <fcntl.h>
 #endif
 
 void setup() {
-#ifdef __EMSCRIPTEN__
-  EM_ASM(
-    FS.mkdir('working');
-#if NODEFS
-    FS.mount(NODEFS, { root: '.' }, 'working');
+  int rtn = mkdir("working", 0777);
+  assert(rtn == 0);
+#if defined(__EMSCRIPTEN__) && defined(NODEFS)
+  EM_ASM(FS.mount(NODEFS, { root: '.' }, 'working'));
 #endif
-    FS.chdir('working');
-    FS.symlink('../test/../there!', 'link');
-    FS.writeFile('file', 'test');
-    FS.mkdir('folder');
-  );
-#else
-  mkdir("working", 0777);
-  chdir("working");
+  rtn = chdir("working");
+  assert(rtn == 0);
   symlink("../test/../there!", "link");
-  int fd = open("file", O_RDWR);
-  write(fd, "test", 5);
+  int fd = open("file", O_RDWR | O_CREAT, 0777);
+  assert(fd >= 0);
+  rtn = write(fd, "test", 5);
+  assert(rtn == 5);
   close(fd);
-  mkdir("folder", 0777);
-#endif
+  rtn = mkdir("folder", 0777);
+  assert(rtn == 0);
 }
 
 int main() {

test/unistd/symlink_on_nodefs.c

@@ -5,6 +5,7 @@
  * found in the LICENSE file.
  */
 
+#include <assert.h>
 #include <stdio.h>
 #include <errno.h>
 #include <unistd.h>
@@ -14,52 +15,39 @@
 #include <limits.h>
 #include <stdlib.h>
 
-int main() {
+void setup() {
   EM_ASM(
-    fs.mkdirSync('./new-directory', '0777');
-    fs.writeFileSync('./new-directory/test', 'Link it');
-    fs.symlinkSync(fs.realpathSync('./new-directory'), './symlink');
+    fs.mkdirSync('new-directory', '0777');
+    fs.writeFileSync('new-directory/test', 'Link it');
+    fs.symlinkSync(fs.realpathSync('new-directory'), 'symlink');
 
     FS.mkdir('working');
     FS.mount(NODEFS, { root: '.' }, 'working');
 
     FS.mkdir('direct-link');
-    FS.mount(NODEFS, { root: './symlink' }, 'direct-link');
+    FS.mount(NODEFS, { root: 'symlink' }, 'direct-link');
   );
+}
 
-  {
-    const char* path = "/working/symlink/test";
-    printf("reading %s\n", path);
+int main() {
+  setup();
 
-    FILE* fd = fopen(path, "r");
-    if (fd == NULL) {
-      printf("failed to open file %s\n", path);
-    }
-    else {
-      char buffer[8];
-      fread(buffer, 1, 7, fd);
-      buffer[7] = 0;
-      printf("buffer is %s\n", buffer);
-      fclose(fd);
-    }
-  }
+  char buf[1024];
+  readlink("/working/symlink", buf, 1024);
+  printf("readlink: %s\n", buf);
 
-  printf("\n");
+  FILE* fd = fopen("/working/symlink/test", "r");
+  assert(fd);
+  char buffer[8] = {0};
+  int rtn = fread(buffer, 1, 7, fd);
+  assert(rtn == 7);
+  printf("buffer is '%s'\n", buffer);
+  fclose(fd);
 
-  {
-    const char* path = "/direct-link/test";
-    printf("reading %s\n", path);
+  // This should fail, since it resolves to ../new-directory which is not
+  // mounted
+  fd = fopen("/direct-link/test", "r");
+  assert(fd == NULL);
 
-    FILE* fd = fopen(path, "r");
-    if (fd != NULL) {
-      // This should not happen, it resolves to ../new-directory which is not mounted
-      printf("opened file %s\n", path);
-      fclose(fd);
-    }
-    else {
-      printf("failed to open file %s\n", path);
-    }
-  }
-
   return 0;
 }

test/unistd/symlink_on_nodefs.out

@@ -1,5 +1,2 @@
-reading /working/symlink/test
-buffer is Link it
-
-reading /direct-link/test
-failed to open file /direct-link/test
+readlink: /working/new-directory
+buffer is 'Link it'

tools/utils.py

@@ -84,9 +84,8 @@ def write_binary(file_path, contents):
 
 def delete_file(filename):
   """Delete a file (if it exists)."""
-  if not os.path.exists(filename):
-    return
-  os.remove(filename)
+  if os.path.lexists(filename):
+    os.remove(filename)
 
 
 def delete_dir(dirname):