When should I use O_CLOEXEC when I open file in Linux?

Question

My process forks several times, and each time the child will exec - means I want it to run some other program.

In the main process I open a file descriptor with the open() syscall.

Would it be correct to give it a flag O_CLOEXEC so the new program that I run with exec() wouldn't have the fd resource?

see also: [man 2 open](https://man7.org/linux/man-pages/man2/open.2.html) — milahu, Sep 04 '22 at 17:47

score 24 · Accepted Answer · answered Mar 16 '13 at 09:33

24

Yes, unless you need the program you exec to have access to that file descriptor. You can also close the file descriptor manually in the child process before calling exec, but that's more error prone.

answered Mar 16 '13 at 09:33

8

An old (but error-prone) practice was to `for (int=3; i<256; i++) close(i);` just before the `execve`, leaving only stdin, stdout, stderr .... – Basile Starynkevitch Mar 16 '13 at 12:40

When should I use O_CLOEXEC when I open file in Linux?

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