memory leak in resolver

[Brian Fundakowski Feldman]

On Wed, Feb 16, 2005 at 12:16:26PM +0100, Dag-Erling Smørgrav wrote:
> des at xps ~/src/gai% cat gai.c
> #include <sys/types.h>
> #include <sys/socket.h>
> #include <netdb.h>
> #include <string.h>
> 
> int
> main(void)
> {
>         struct addrinfo hint, *res;
> 
>         memset(&hint, 0, sizeof(hint));
>         hint.ai_family = AF_INET;
>         hint.ai_socktype = SOCK_STREAM;
>         hint.ai_protocol = 0;
>         if (getaddrinfo("www.freebsd.org", "http", &hint, &res) == 0)
>                 freeaddrinfo(res);
>         return (0);
> }
> des at xps ~/src/gai% valgrind --leak-check=yes --num-callers=8 ./gai
> ==44998== Memcheck, a memory error detector for x86-linux.
> ==44998== Copyright (C) 2002-2004, and GNU GPL'd, by Julian Seward.
> ==44998== Using valgrind-2.1.0, a program supervision framework for x86-linux.
> ==44998== Copyright (C) 2000-2004, and GNU GPL'd, by Julian Seward.
> ==44998== Estimated CPU clock rate is 3591 MHz
> ==44998== For more details, rerun with: -v
> ==44998==
> ==44998==
> ==44998== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
> ==44998== malloc/free: in use at exit: 2328 bytes in 11 blocks.
> ==44998== malloc/free: 45 allocs, 34 frees, 232569 bytes allocated.
> ==44998== For counts of detected errors, rerun with: -v
> ==44998== searching for pointers to 11 not-freed blocks.
> ==44998== checked 1258740 bytes.
> ==44998==
> ==44998== 49 bytes in 5 blocks are definitely lost in loss record 2 of 5
> ==44998==    at 0x3C033173: malloc (vg_replace_malloc.c:105)
> ==44998==    by 0x3C0D567E: strdup (strdup.c:52)
> ==44998==    by 0x3C0D0403: _nsyylex (nslexer.l:88)
> ==44998==    by 0x3C0CF903: _nsyyparse (y.tab.c:380)
> ==44998==    by 0x3C0D296E: _nsdispatch (nsdispatch.c:353)
> ==44998==    by 0x3C0C6E33: getaddrinfo (getaddrinfo.c:1646)
> ==44998==    by 0x804856C: main (gai.c:15)
> ==44998==
> ==44998== LEAK SUMMARY:
> ==44998==    definitely lost: 49 bytes in 5 blocks.
> ==44998==    possibly lost:   0 bytes in 0 blocks.
> ==44998==    still reachable: 2279 bytes in 6 blocks.
> ==44998==         suppressed: 0 bytes in 0 blocks.
> ==44998== Reachable blocks (those to which a pointer was found) are not shown.
> ==44998== To see them, rerun with: --show-reachable=yes
> 
> The amount of memory leaked seems constant regardless of how many
> times getaddrinfo() is called, so it's probably from reading
> resolv.conf.

It looks like the memory leaked scales with the number of times that
the mtime of the configuration file changes during the process's lifetime.
(Of course, starting at one leak the first time it's used.)

-- 
Brian Fundakowski Feldman                           \'[ FreeBSD ]''''''''''\
  <> green at FreeBSD.org                               \  The Power to Serve! \
 Opinions expressed are my own.                       \,,,,,,,,,,,,,,,,,,,,,,\