2006-03-24

Report-an-Apple-bug Friday! 15

This bug is Terminal leaves files open when invoking shell directly. It was filed on 2006-03-24 at 23:45 PST.

UPDATE 2006-03-25: Uploaded the test app to GeoCities. Linked below.


Summary:

When Terminal invokes a specific shell directly, rather than by invoking /usr/bin/login, several files are left open.

Steps to Reproduce:

  1. Launch Terminal.
  2. Terminal menu→Preferences….
  3. Select “Execute this command (specify complete path):”
  4. Specify the complete path.
  5. File menu→New Shell.
  6. Run the attached test app, or run ps and then run lsof with the pid of the shell.

Expected Results:

The test app prints “3”. lsof reports only three file descriptors: 0, 1, and 2, the respective FDs of stdin, stdout, and stderr.

Actual Results:

The test app prints “10”, “11”, “14”, or some other number. lsof reports a lot of open files having to do with Carbon (suggesting that the shell probably did not open them itself).

Regression:

None known.

Notes:

The test program creates and opens a file, and reports the FD it gets back from open. open returns the first FD that was available. In the absence of any other open files, this should be 3 (because that's the FD after stdin, stdout, and stderr).

When I tested using test-app-free version of the above steps, I did observe that zsh 4.3.1 leaves open one file of its own (the terminal device). Perhaps it opens /dev/tty. This open file is not passed onto subprocesses, however, as is demonstrated by the test app.

Terminal (or Carbon) is responsible for all the other files that Terminal leaves open; this is obvious from the paths of the open files. Maybe login is closing them; in this case, Terminal should do this itself when the user chooses to bypass login.


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