RE: [reSIProcate] I really do believe I found a problem in Resip

["Leon Thrane" <sipfoundry-1@xxxxxxxxxx>]

If I remember correctly, 'gethostbyname()' is not re-entrant.

-----Original Message-----
From: resiprocate-devel-bounces@xxxxxxxxxxxxxxxxxxx
[mailto:resiprocate-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of John
Draper
Sent: Monday, December 05, 2005 2:51 PM
To: Resip Devel
Subject: [reSIProcate] I really do believe I found a problem in Resip

Hi,

In relation to a previous post I did last night, I finally traced it down to
the "offending" instruction... 

Sometime, before I call and issue the resip Register command, I call a
routine I wrote called...getMyIPAddress

It's supposed to return my local hostname, and return an IP address as a
char * pointing to a dotted IP address.

This is the function....

char * getMyIPAddress(char *myhostname)
{
    int        result;
    struct hostent *myHost;
    struct in_addr dstAddr;
    char *ip;
   
    result = gethostname(myhostname, 100);
    if (result == -1)
        return NULL;
   
    myHost = malloc(sizeof (struct hostent));
    myHost = gethostbyname(myhostname);         <---- I call this, it 
breaks resip
    memcpy((char *) &dstAddr, myHost->h_addr_list[0], myHost->h_length);
    ip = inet_ntoa(dstAddr);
    free(myHost);
    return(ip);
}

Note the <---- above

If I comment this statement out,  resip works great.  But when I leave it
in,  I get a crash in DnsUtil.cxx... 

Data
DnsUtil::getLocalHostName()
{
   char buffer[MAXHOSTNAMELEN];
   if (int e = gethostname(buffer,sizeof(buffer)) == -1)
   {
      if ( e != 0 )
      {
         int err = getErrno();
         switch (err)
         {
            case WSANOTINITIALISED:
               CritLog( << "could not find local hostname because netwrok
not initialized:" << strerror(err) );
               break;
            default:
               CritLog( << "could not find local hostname:" <<
strerror(err) );
               break;
         }
         throw Exception("could not find local hostname",__FILE__,__LINE__);
      }
   }
   struct hostent* he;
   if ((he = gethostbyname(buffer)) != NULL) {       <---- when I get 
here....
     if (strchr(he->h_name, '.') != NULL) {
       strncpy(buffer, he->h_name, sizeof(buffer));
     }
     else {
       WarningLog( << "local hostname does not contain a domain part");
     }
   }
   return Data(buffer);
}

So,  long after I call MY GetMyIPAddress routine you see above,  when I get
to the indicated function above,  I get the following in my error logs...

resiprocate/dum/UserProfile.cxx:91 | Adding credential: 
realm=213.167.79.25 user=u354
Current language:  auto; currently objective-c++
*** malloc[3178]: Deallocation of a pointer not malloced: 0xa01c05f4; This
could be a double free(), or free() called with the middle of an allocated
block; Try setting environment variable MallocHelp to see tools to help
debug
*** malloc[3178]: Deallocation of a pointer not malloced: 0x809e017c; This
could be a double free(), or free() called with the middle of an allocated
block; Try setting environment variable MallocHelp to see tools to help
debug
*** malloc[3178]: Deallocation of a pointer not malloced: 0x7c050378; This
could be a double free(), or free() called with the middle of an allocated
block; Try setting environment variable MallocHelp to see tools to help
debug

when I stop the program,  it always stops at the above indicated
function....

Ok,  so next I put a breakpoint at that function,  run it until I break
there, then single step past the "gethostbyname" function above,  I get the
output you see above.

Next,  I commented out MY call to "gethostbyname" and resip works just
fine...

Can someone shed some light on this...   perhaps someone could try 
calling that
function before registering and see if they get the same results...

I'm already aware my "getMyIPAddress" will ONLY work on a machine with a
single network device on it.  And they also mentioned it in the header file
of DnsUtil.h...

      // Note that this will not work on systems with more than one ethernet
      // interface. You are advised to use getInterfaces instead in those
      // cases.
      static Data getLocalIpAddress(const Data&
defaultInterface=Data::Empty) ;

As an updated version of this function been submitted to the project? 

I can get along with using a single device for now,  until I get the rest of
the SIP phone working,  but is someone going to eventually address this
issue?

Now,  I don't really need to use my "offending" routine above if I can
somehow get the resip stack to return my IP address.  I would assume I could
call some method after calling...

    clientDum->addTransport(UDP, 5060);

Is that right?

have I made an error in the way I coded the "getMyIPAddress"
above.....   Does the "gethostbyname" try and free the "myhostname"
pointer (which I allocate prior to calling this function).

In the statement...

ip = inet_ntoa(dstAddr);

This returns a "char *" - Am I to assume this has been allocated by the
inet_ntoa function above???

John



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