Message-ID: <43526851.3030406@ruault.com>
From: Charles-Edouard Ruault <ce@ruault.com>
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To: bluez-users@lists.sourceforge.net
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Subject: [Bluez-users] SEGV when searching for L2CAP port
Sender: bluez-users-admin@lists.sourceforge.net
Errors-To: bluez-users-admin@lists.sourceforge.net
Reply-To: bluez-users@lists.sourceforge.net
Date: Sun, 16 Oct 2005 16:48:49 +0200

Hi All,
I'm writing an app in C on linux using the latest bluez-libs (2.2.21 ).
The app is very simple, it's seaching for service on a device using it's 
UUID and retrives the SDP port to be used to connect to the remote service.
I'm kind of new to bluez programming so forgive me if i'm totally off 
tracks but here's what i'm doing :

    uint32_t addlistener_uuid_int[] = { 0xAAA2689C, 0xD711C01E, 
0xB0006C9E, 0xEC763DD0 };
    if (!(s = sdp_connect(src, dst, 0)))
    {
      printf("Failed to connect\n");
      return ERROR;
    }
    sdp_uuid128_create(&svclass, &addlistener_uuid_int);
    srch = sdp_list_append(NULL, &svclass);
    uint32_t range = 0x0000ffff;
    attrs = sdp_list_append( NULL, &range );
    err = sdp_service_search_attr_req( s, srch, SDP_ATTR_REQ_RANGE, 
attrs, &rsp);
    sdp_close(s);
    if (err)
    {
      printf("sdp_service_search_req failed : %d\n", err);
      return ERROR;
    }
   
    sdp_list_t *r = rsp;
    if ((r==NULL) || (r->next==NULL))
    {
      printf("Empty service list ...\n");
      return -1;
    }
    psm=sdp_get_proto_port(rsp, L2CAP_UUID);

I'm getting a SEGV in the function sdp_get_proto_port.
I've debugged into the function and i found that sdp_get_port crashes on 
the outlined line below because p->next does not contains a valid 
address, it contains 0x10008 which is the service record handler of the 
service i'm looking for.

int sdp_get_proto_port(const sdp_list_t *list, int proto)
{
        if (proto != L2CAP_UUID && proto != RFCOMM_UUID) {
                errno = EINVAL;
                return -1;
        }

        for (; list; list = list->next) {
                sdp_list_t *p;
                for (p = list->data; p; p = p->next) {
                        sdp_data_t *seq = (sdp_data_t *) p->data; /// 
CRASH HERE BECAUSE p==0x10008
                        int port = __find_port(seq, proto);
                        if (port)
                                return port;
                }
        }
        return 0;
}

Here's what an hcidump of the transaction looks like:

device: hci0 snap_len: 1028 filter: 0xffffffff
< HCI Command: Create Connection (0x01|0x0005) plen 13
 > HCI Event: Command Status (0x0f) plen 4
 > HCI Event: Link Key Request (0x17) plen 6
< HCI Command: Link Key Request Reply (0x01|0x000b) plen 22
 > HCI Event: Command Complete (0x0e) plen 10
 > HCI Event: Connect Complete (0x03) plen 11
< ACL data: handle 6 flags 0x02 dlen 12
    L2CAP(s): Connect req: psm 1 scid 0x0040
< HCI Command: Write Link Policy Settings (0x02|0x000d) plen 4
 > HCI Event: Command Complete (0x0e) plen 6
 > HCI Event: Max Slots Change (0x1b) plen 3
 > HCI Event: Number of Completed Packets (0x13) plen 5
 > ACL data: handle 6 flags 0x02 dlen 16
    L2CAP(s): Connect rsp: dcid 0x0044 scid 0x0040 result 1 status 2
      Connection pending - Authorization pending
 > ACL data: handle 6 flags 0x02 dlen 16
    L2CAP(s): Connect rsp: dcid 0x0044 scid 0x0040 result 0 status 0
      Connection successful
< ACL data: handle 6 flags 0x02 dlen 12
    L2CAP(s): Config req: dcid 0x0044 flags 0x00 clen 0
 > ACL data: handle 6 flags 0x02 dlen 12
    L2CAP(s): Config req: dcid 0x0040 flags 0x00 clen 0
< ACL data: handle 6 flags 0x02 dlen 14
    L2CAP(s): Config rsp: scid 0x0044 flags 0x00 result 0 clen 0
      Success
 > HCI Event: Number of Completed Packets (0x13) plen 5
 > HCI Event: Number of Completed Packets (0x13) plen 5
 > ACL data: handle 6 flags 0x02 dlen 14
    L2CAP(s): Config rsp: scid 0x0040 flags 0x00 result 0 clen 0
      Success
< ACL data: handle 6 flags 0x02 dlen 38
    L2CAP(d): cid 0x0044 len 34 [psm 1]
        SDP SSA Req: tid 0x0 len 0x1d
          pat uuid-128 9c68a2aa-1ec0-11d7-9e6c-00b0d03d76ec
          max 65535
          aid(s) 0x0000 - 0xffff
          cont 00
 > HCI Event: Number of Completed Packets (0x13) plen 5
 > ACL data: handle 6 flags 0x02 dlen 105
    L2CAP(d): cid 0x0040 len 101 [psm 1]
        SDP SSA Rsp: tid 0x0 len 0x60
          count 93
          record #0
              aid 0x0000 (SrvRecHndl)
                 uint 0x10008
              aid 0x0001 (SrvClassIDList)
                 < uuid-128 9c68a2aa-1ec0-11d7-9e6c-00b0d03d76ec >
              aid 0x0004 (ProtocolDescList)
                 < < uuid-16 0x0100 (L2CAP) uint 0x1001 > >
              aid 0x0005 (BrwGrpList)
                 uuid-16 0x1002 (PubBrwsGrp)
              aid 0x0006 (LangBaseAttrIDList)
                 < uint 0x656e uint 0x6a uint 0x100 >
              aid 0x0100 (SrvName)
                 str "AdListener"
              aid 0x4321 (unknown)
                 str "Coucou"
          cont 00
< ACL data: handle 6 flags 0x02 dlen 12
    L2CAP(s): Disconn req: dcid 0x0044 scid 0x0040
 > HCI Event: Number of Completed Packets (0x13) plen 5
 > ACL data: handle 6 flags 0x02 dlen 12
    L2CAP(s): Disconn rsp: dcid 0x0044 scid 0x0040
< HCI Command: Disconnect (0x01|0x0006) plen 3
 > HCI Event: Command Status (0x0f) plen 4
 > HCI Event: Disconn Complete (0x05) plen 4

So my question is : What am i doing wrong ? What's the correct method to 
retrive the psm to use to connect to my L2CAP service ?
Thanks in advance.
Regards.

-- 
Charles-Edouard Ruault
PGP Key ID E4D2B80C


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