Date: Thu, 19 Apr 2007 19:14:56 -0500 (CDT) From: "Sean C. Farley" <sean-freebsd@farley.org> To: freebsd-current@freebsd.org Subject: Fix for memory leak in setenv/unsetenv (take 2) Message-ID: <20070419175902.R44041@thor.farley.org>
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I have a new patch[1] that fixes memory leaks caused by repeated calls
to setenv() with varying-sized values or unsetenv(). The web page has a
better description about it.
I tested this with -STABLE with various applications. Also, to help
check it further, I wrote a few regression tests for it.
Notes/questions I have:
1. Would making it more IEEE Std 1003.1-compliant be desired?
a. FreeBSD's setenv() allows an '=' in the name and value to comply
with other standards while this standard disallows it.
b. FreeBSD's unsetenv() does not have a return value while this
standard returns an int. For the changes I made, this would be
beneficial.
2. The "feature"--it is under the BUGS section :)--of keeping all
pointers returned by previous calls to getenv() valid regardless of
any calls to setenv() is still there. Keeping this requirement
prevents a complete fix.
3. I previously thought about having the implementation initialize
itself upon the library loading or called within crt1.c. The problem
with a library-load time method is that changes made to the environ
variable do not persist at the execution of main(). The issue with
calling it within crt1.c is that FreeBSD's malloc() would need to
call __findenv_environ() to find MALLOC_OPTIONS when it is
initialized to prevent a recursion into each other. jasone@ helped
me look at this.
4. Ignore dmalloc defines for now; they will be removed.
Basically, the patch contains sysenv.c and a change to the Makefile to
remove building of putenv.c and setenv.c. To increase the speed of
putenv(), I have moved it into sysenv.c to make use of some internal
(static) functions. I have just started with it, but I may leave it
alone.
Please let me know if you see any bugs.
Sean
1. http://www.farley.org/freebsd/tmp/setenv-6/
--
sean-freebsd@farley.org
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