lib: fix realpathSync resolving to invalid path (#54200)

lib/fs.js

@@ -2731,6 +2731,14 @@ function realpathSync(p, options) {
       }
       resolvedLink = pathModule.resolve(previous, linkTarget);
 
+      // If resolvedLink is not valid or is a pipe/socket, stop resolving, break out of the loop
+      // issue: https://github.com/nodejs/node/issues/54200
+      const resolvedLinkStats = binding.lstat(resolvedLink, false, undefined, false /* throwIfNoEntry */);
+      if (!resolvedLinkStats || isFileType(resolvedLinkStats, S_IFIFO) ||
+        isFileType(resolvedLinkStats, S_IFSOCK)) {
+        break;
+      }
+
       cache?.set(base, resolvedLink);
       if (!isWindows) seenLinks.set(id, linkTarget);
     }

test/parallel/test-linux-dev-stdin.js

@@ -0,0 +1,38 @@
+'use strict';
+const common = require('../common');
+const tmpdir = require('../common/tmpdir');
+const fs = require('fs');
+
+//
+// This test ensures Node.js doesn't crash when reading from /dev/stdin as an input.
+// ref: https://github.com/nodejs/node/issues/54200
+//
+
+if (!fs.existsSync('/dev/stdin')) {
+  common.skip('Only test on platforms having /dev/stdin');
+}
+
+const child_process = require('child_process');
+const assert = require('assert');
+const { describe, it } = require('node:test');
+
+describe('Test reading SourceCode from stdin and it\'s symlinks', () => {
+  it('Test reading sourcecode from /dev/stdin', () => {
+    const cp = child_process.execSync(`printf 'console.log(1)' | "${process.execPath}" /dev/stdin`, { stdio: 'pipe' });
+    assert.strictEqual(cp.toString(), '1\n');
+  });
+
+  it('Test reading sourcecode from a symlink to /dev/stdin', () => {
+    tmpdir.refresh();
+    const tmp = tmpdir.resolve('./stdin');
+    fs.symlinkSync('/dev/stdin', tmp);
+    const cp2 = child_process.execSync(`printf 'console.log(2)' | "${process.execPath}" ${tmp}`, { stdio: 'pipe' });
+    assert.strictEqual(cp2.toString(), '2\n');
+  });
+
+  it('Test reading sourcecode from a symlink to the `readlink /dev/stdin`', () => {
+    const devStdin = fs.readlinkSync('/dev/stdin');
+    const cp3 = child_process.execSync(`printf 'console.log(3)' | "${process.execPath}" "${devStdin}"`, { stdio: 'pipe' });
+    assert.strictEqual(cp3.toString(), '3\n');
+  });
+});