On Fri, May 03, 2013 at 12:11:19PM -0400, Jeffrey Johnson wrote:
>
> On May 2, 2013, at 5:56 PM, Karl Lindén wrote:
>
> > Hello!
> >
> > I am memory checking a program using the popt library but it seems as
> > there is some kind of memory leak in poptGetNextOpt. I have written a
> > small test program to show the issue. The program will basically just
> > take an integer argument and print the integer to the prompt. Of
> > course, the program works as expected, but valgrind records a leak.
> >
> > I am attaching the test program. The valgrind output I will post
> > further down this mail.
> >
> > I'm using popt version 1.16.
> >
> > The program was compiled with the following command:
> > $ gcc -lpopt popt_test.c -o popt_test
> >
> > $ valgrind --leak-check=full ./popt_test -i 890
> > ==1170== Memcheck, a memory error detector
> > ==1170== Copyright (C) 2002-2012, and GNU GPL'd, by Julian Seward et al.
> > ==1170== Using Valgrind-3.8.1 and LibVEX; rerun with -h for copyright info
> > ==1170== Command: ./popt_test -i 890
> > ==1170==
> > integer = 890
> > ==1170==
> > ==1170== HEAP SUMMARY:
> > ==1170== in use at exit: 4 bytes in 1 blocks
> > ==1170== total heap usage: 6 allocs, 5 frees, 882 bytes allocated
> > ==1170==
> > ==1170== 4 bytes in 1 blocks are definitely lost in loss record 1 of 1
> > ==1170== at 0x4A099EB: malloc (in
> > /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
> > ==1170== by 0x4C3372D: expandNextArg (popt.c:696)
> > ==1170== by 0x4C34FD4: poptGetNextOpt (popt.c:1498)
> > ==1170== by 0x400873: main (in /home/kalle/popt_test)
> > ==1170==
> > ==1170== LEAK SUMMARY:
> > ==1170== definitely lost: 4 bytes in 1 blocks
> > ==1170== indirectly lost: 0 bytes in 0 blocks
> > ==1170== possibly lost: 0 bytes in 0 blocks
> > ==1170== still reachable: 0 bytes in 0 blocks
> > ==1170== suppressed: 0 bytes in 0 blocks
> > ==1170==
> > ==1170== For counts of detected and suppressed errors, rerun with: -v
> > ==1170== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 2 from 2)
> >
> > Should I do something to free the memory or is it some kind of bug?
> >
>
> The "leak" is actually a side effect of a design flaw returning strings to
> applications.
>
> A proper fix would involve changing how returned option value memory is
> managed.
>
> I'm not sure there's sufficient interest to justify a proper fix.
>
> 73 de Jeff
>
Before patch:
~snip~
$ valgrind rpm -q --qf="1234" rpm
...
==21963== definitely lost: 5 bytes in 1 blocks
$ valgrind rpm -q --qf="1234" --qf="12" rpm
...
==21964== definitely lost: 3 bytes in 1 blocks
~snip~
After patch:
~snip~
$ valgrind rpm -q --qf="1234" rpm
...
==21971== definitely lost: 0 bytes in 0 blocks
$ valgrind rpm -q --qf="1234" --qf="12" rpm
...
==21973== definitely lost: 0 bytes in 0 blocks
~snip~
--- popt.c.orig 2016-02-12 12:28:52.670214800 +0900
+++ popt.c 2016-02-12 12:25:28.266214800 +0900
@@ -229,7 +229,7 @@ void poptResetContext(poptContext con)
con->os->argb = PBM_FREE(con->os->argb);
con->os->currAlias = NULL;
con->os->nextCharArg = NULL;
- con->os->nextArg = NULL;
+ con->os->nextArg = _free(con->os->nextArg);
con->os->next = 1; /* skip argv[0] */
con->numLeftovers = 0;
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