Red Hat Bugzilla – Bug 468440
atexit() hooks are not called on exec()
Last modified: 2008-10-30 08:35:28 EDT
Description of problem:
"man 3 exit" says, amongst other:
The exit() function causes normal process termination and the value of status & 0377 is returned to the parent (see wait(2)).
All functions registered with atexit(3) and on_exit(3) are called, in the reverse order of their registration.
However, the atexit() hooks are never called if you invoke any of the exec*() functions.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Copy the example from 'man 3 atexit' to test.c
2. Modify it so that instead of "exit(EXIT_SUCCESS)" at the end we have, for example:
execl ("/bin/ls", "ls");
3. Compile and run the example
ATEXIT_MAX = 2147483647
ATEXIT_MAX = 2147483647
That was all, folks
I think it is a serious bug as it does not allow applications that rely on it to cleanup things that won't automatically cleanup during a normal process destruction.
I tried on a micro linux-from-scratch variant I have running here in a virtual machine, and the bug is still there, so it's really a upstream bug.
I have copied the report to the bugzilla recommended on glibc homepage, and added a link to that bugzilla.
I was told by Ulrich Drepper that this is behaviour is conformant to standards.
I found in the "The Open Group Base Specifications issue 6" the page related to exec() here:
The only quote mentioning atexit is:
<<After a successful call to any of the exec functions, any functions previously registered by atexit() or pthread_atfork() are no longer registered.>>
This is somehow vague, but anyway I think this can be re-classified as a bug in the man page. FreeBSD and Solaris man pages just repeat the same quote from standard.
Changing target package to man-pages-2.78-2.fc9.noarch.
The description details from which results the fact - the atexit stuff is not called before the execl call starts - are on execve page (there is link from execl page):
"All process attributes are preserved during an execve(), except the following:
* Exit handlers are not preserved (atexit(3), on_exit(3)).
It seems for me to be sufficient info so I think there is no need to add another notice about it.
Indeed, there's a note on execve() page.
I do not insist, but I think it would be helpful to note this on exec page as well. And even emphasize that the handlers are not called, not just "not preserved". Maybe I don't understand it well, but "handlers are not preserved" and "handlers are not called and not preserved" sound a bit different to me.
Anyway, this bug can be closed I think.