[OpenSER-Devel] pkg_malloc and pkg_free

[Phil D'Amore]

Daniel:

I believe it is the responsibility of the free_lump() function (see
data_lump.c) to free that memory.  You only need to pkg_free if the
lump insert actually fails.  Normally lumps are automatically freed
when the rest of the message structure is freed, and you don't need to
worry about it.

Thanks,
Phil

On Dec 10, 2007 1:02 PM, Daniel Corbe <daniel.junkmail at gmail.com> wrote:
> Also,
>
> What's the point in having packaged based implementations of malloc() and
> free() if they don't do anything more than the stock versions of each
> function?
>
> -Daniel
>
>
> On Dec 10, 2007 12:59 PM, Daniel Corbe <daniel.junkmail at gmail.com> wrote:
> > So then there's a memory leak in my module and in the UAC module as well.
> >
> >
> > Consider the following scenario:
> >
> >
> > I'm using lumps to change the To: header in a SIP message to interop with
> a broken (non RFC-compliant) SIP-enabled voicemail system.
> >
> >
> > I took my example from the UAC module, because the UAC module has a
> function which swaps out the From: header with something else.
> >
> >
> > Consider this code snippet:
> >
> >
> >
> >
> > static int replace_to_uri(struct sip_msg *msg, str *uri)
> >
> > {
> >
> > struct to_body *to;
> >
> > struct lump* l;
> >
> > char *p;
> >
> >
> >
> > to = (struct to_body *)msg->to->parsed;
> >
> >
> >
> > if ((l = del_lump(msg, to->uri.s-msg->buf, to->uri.len , 0)) == 0)
> >
> > {
> >
> > LOG(L_ERR,"Delete lump failed\n" );
> >
> > return( 0);
> >
> > }
> >
> > p = pkg_malloc(uri->len);
> >
> > if (p == 0)
> >
> > {
> >
> > LOG(L_ERR, "Out of memory!\n" );
> >
> > pkg_free(p);
> >
> > return( 0);
> >
> > }
> >
> > memcpy(p, uri->s, uri->len);
> >
> > if (insert_new_lump_after(l, p, uri->len, 0) == 0)
> >
> > {
> >
> > LOG(L_ERR, "Insert new lump failed\n" );
> >
> > pkg_free(p);
> >
> > return( 0);
> >
> > }
> >
> >
> >
> > //pkg_free(p);
> >
> > return( 1);
> >
> > }
> >
> >
> > If I call pkg_free at the end of the function, the heap memory which
> stores my new to: URI is no longer valid memory and is not guaranteed to
> continue to hold the string which I'm trying to pass -- and in fact on my
> FreeBSD machine it never does.
> >
> >
> > I have to NOT call pkg_free in order for there not to be garbage in my To:
> >
> >
> > the UAC module suffers from the same problem.  Take a look at
> modules/uac/from.c, replace from function:
> >
> >
> >
> >
> > /* build del/add lumps */
> >
> > if ((l=del_lump( msg, from->uri.s-msg->buf, from-> uri.len, 0))==0)
> >
> > {
> >
> > LOG(L_ERR,"ERROR:uac:replace_from: del lump failed\n" );
> >
> > goto error;
> >
> > }
> >
> > p = pkg_malloc( from_uri->len);
> >
> > if (p==0)
> >
> > {
> >
> > LOG(L_ERR,"ERROR:uac:replace_from: no more pkg mem\n" );
> >
> > goto error;
> >
> > }
> >
> > memcpy( p, from_uri->s, from_uri->len);
> >
> > if (insert_new_lump_after( l, p, from_uri->len, 0)==0)
> >
> > {
> >
> > LOG(L_ERR,"ERROR:uac:replace_from: insert new lump failed\n" );
> >
> > pkg_free(p);
> >
> > goto error;
> >
> > }
> >
> >
> >
> >
> > if (from_restore_mode==FROM_NO_RESTORE)
> >
> > return 0;
> >
> >
> >
> >
> > As you can see we only call pkg-free if an error occurs.  Won't this leak?
> >
> >
> >
> >
> >
> > -Daniel
> >
> >
> >
> >
> >
> > On Dec 10, 2007 4:24 AM, Bogdan-Andrei Iancu <bogdan at voice-system.ro>
> wrote:
> >
> > > Hi Daniel,
> > >
> > > if you allocate memory, you need to explicitly free it - there is no
> > > garbage collector like system in openser.
> > >
> > > regards,
> > > bogdan
> > >
> > >
> > >
> > >
> > > Daniel Corbe wrote:
> > > > I have a question,
> > > >
> > > > If I call pkg_malloc(), and don't call pkg_free, does OpenSER know to
> > > > free() the memory later?  And if so, when does the message get free'd
> > > > exactly?
> > > >
> > > > -Daniel
> > > >
> > > >
> ------------------------------------------------------------------------
> > > >
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> > > >
> > >
> > >
> >
> >
>
>
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