add an optional node to FS.ErrnoError, and use it in stat to tell if an error is about the relevant file - if not, it occurred when looking up its parents, and we should emit ENOTDIR; fixes #2669

src/library.js

@@ -283,6 +283,10 @@ LibraryManager.library = {
       {{{ makeSetValue('buf', C_STRUCTS.stat.st_ino, 'stat.ino', 'i32') }}};
       return 0;
     } catch (e) {
+      if (e.node && PATH.normalize(path) !== PATH.normalize(FS.getPath(e.node))) {
+        // an error occurred while trying to look up the path; we should just report ENOTDIR
+        e.setErrno(ERRNO_CODES.ENOTDIR);
+      }
       FS.handleFSError(e);
       return -1;
     }

src/library_fs.js

@@ -161,7 +161,7 @@ mergeInto(LibraryManager.library, {
     lookupNode: function(parent, name) {
       var err = FS.mayLookup(parent);
       if (err) {
-        throw new FS.ErrnoError(err);
+        throw new FS.ErrnoError(err, parent);
       }
       var hash = FS.hashName(parent.id, name);
 #if CASE_INSENSITIVE_FS
@@ -1299,14 +1299,18 @@ mergeInto(LibraryManager.library, {
     },
     ensureErrnoError: function() {
       if (FS.ErrnoError) return;
-      FS.ErrnoError = function ErrnoError(errno) {
-        this.errno = errno;
-        for (var key in ERRNO_CODES) {
-          if (ERRNO_CODES[key] === errno) {
-            this.code = key;
-            break;
+      FS.ErrnoError = function ErrnoError(errno, node) {
+        this.node = node;
+        this.setErrno = function(errno) {
+          this.errno = errno;
+          for (var key in ERRNO_CODES) {
+            if (ERRNO_CODES[key] === errno) {
+              this.code = key;
+              break;
+            }
           }
-        }
+        };
+        this.setErrno(errno);
         this.message = ERRNO_MESSAGES[errno];
 #if ASSERTIONS
         if (this.stack) this.stack = demangleAll(this.stack);

tests/test_other.py

@@ -3983,3 +3983,79 @@ main(const int argc, const char * const * const argv)
     test([])
     test(['-O1'])
 
+  def test_stat_fail_alongtheway(self):
+    open('src.cpp', 'w').write(r'''
+#include <errno.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <string.h>
+
+#define CHECK(expression) \
+  if(!(expression)) {                            \
+    error = errno;                               \
+    printf("FAIL: %s\n", #expression); fail = 1; \
+  } else {                                       \
+    error = errno;                               \
+    printf("pass: %s\n", #expression);           \
+  }                                              \
+
+int
+main()
+{
+  int error;
+  int fail = 0;
+  CHECK(mkdir("path", 0777) == 0);
+  CHECK(close(open("path/file", O_CREAT | O_WRONLY, 0644)) == 0);
+  {
+    struct stat st;
+    CHECK(stat("path", &st) == 0);
+    CHECK(st.st_mode = 0777);
+  }
+  {
+    struct stat st;
+    CHECK(stat("path/nosuchfile", &st) == -1);
+    printf("info: errno=%d %s\n", error, strerror(error));
+    CHECK(error == ENOENT);
+  }
+  {
+    struct stat st;
+    CHECK(stat("path/file", &st) == 0);
+    CHECK(st.st_mode = 0666);
+  }
+  {
+    struct stat st;
+    CHECK(stat("path/file/impossible", &st) == -1);
+    printf("info: errno=%d %s\n", error, strerror(error));
+    CHECK(error == ENOTDIR);
+  }
+  {
+    struct stat st;
+    CHECK(lstat("path/file/impossible", &st) == -1);
+    printf("info: errno=%d %s\n", error, strerror(error));
+    CHECK(error == ENOTDIR);
+  }
+  return fail;
+}
+''')
+    Popen([PYTHON, EMCC, 'src.cpp']).communicate()
+    self.assertContained(r'''pass: mkdir("path", 0777) == 0
+pass: close(open("path/file", O_CREAT | O_WRONLY, 0644)) == 0
+pass: stat("path", &st) == 0
+pass: st.st_mode = 0777
+pass: stat("path/nosuchfile", &st) == -1
+info: errno=2 No such file or directory
+pass: error == ENOENT
+pass: stat("path/file", &st) == 0
+pass: st.st_mode = 0666
+pass: stat("path/file/impossible", &st) == -1
+info: errno=20 Not a directory
+pass: error == ENOTDIR
+pass: lstat("path/file/impossible", &st) == -1
+info: errno=20 Not a directory
+pass: error == ENOTDIR
+''', run_js('a.out.js'))
+