Re: instability

["jeetu.golani@xxxxxxxxx" <jeetu.golani@xxxxxxxxx>]

Hi Aris,

>With libssh 0.5, it's a little different, you have to initialize libssh
threads and call ssh_init(). (libssh does the dirty work of initilalizing
>libcrypto or libgcrypt).

Just want to clarify if what I'm doing for my libssh server is all right. In
principle I have a new ssh_session created for each new connection into the
server.

My ssh_bind is common for all threads and I call ssh_bind_listen. I have a
ssh_session *session (therefore session is a pointer to a pointer) and I
init this pointer first with an session = ssh_new().....I then move into a
loop where I init an individual session element  such as
session[session_count] = ssh_new and then move onto waiting to accept a
connection with a ssh_bind_option...authenticating user...and finally if
authenticated create a new glib thread for that server session....incremenet
session_count.... and this loops.

Sorry for trying to describe code instead of pasting the relevant snippet
here but I don't have access to my comp with the code right now.

Does the above seem in principle to be acceptable and in line with libssh's
threading model....or would ppl recommend a better way to have a
multi-threaded server.

Thanks,

Bye


On Tue, May 24, 2011 at 2:54 AM, Paulo Panhoto <paulo.panhoto@xxxxxxxxx>wrote:

> There are several threads running but each session is only accessed by one
> thread.
>
> Sure, it does help. thanks.
>
>
> On Mon, May 23, 2011 at 6:22 PM, Aris Adamantiadis <aris@xxxxxxxxxxxx>wrote:
>
>> Hi Paulo,
>>
>> Are you using libssh in several threads ? Libssh is threadsafe under two
>> conditions : call ssh_init() outside of threads and initialize threading in
>> the crypto library (http://www.openssl.org/support/faq.html#PROG1).
>> With libssh 0.5, it's a little different, you have to initialize libssh
>> threads and call ssh_init(). (libssh does the dirty work of initilalizing
>> libcrypto or libgcrypt).
>>
>> Hope this helps,
>>
>> Aris
>>
>> Le 23/05/11 21:41, Paulo Panhoto a écrit :
>>
>>  Hello,
>>>
>>> I'm writing a Qt app with libssh. The best approach I've got was this:
>>> wrap ssh in a QThread that emits signals to other components.
>>>
>>>
>>>         session = ssh_new();
>>>
>>>         if (session == NULL)
>>>         {
>>>             throw SSHException(tr("ssh_new failed"));
>>>         }
>>>         const std::string & stdHost = host.toStdString();
>>>         ssh_options_set(session, SSH_OPTIONS_HOST, stdHost.c_str());
>>>         ssh_options_set(session, SSH_OPTIONS_PORT, &port);
>>>         ssh_options_set(session, SSH_OPTIONS_SSH1, &disabled);
>>>         ssh_options_set(session, SSH_OPTIONS_SSH2, &enabled);
>>>
>>>         emit stateChanged(CONNECTING);
>>>         emit debugInfo(tr("Conecting to %0:%1").arg(host).arg(port));
>>>         if (ssh_connect(session) != SSH_OK)
>>>         {
>>>             throw SSHException(QString("ssh_connect:
>>> %1").arg(ssh_get_error(session)));
>>>         }
>>>
>>> This piece of code is causing me trouble: I'm running it on a opensuse
>>> 11.3 and tested it with libssh 0.4.2 (the "branding" release) and 0.4.8.
>>>
>>> When I compile it against OpenSSL, I get aborts due to double free
>>> inside libcrypto: works most of the time when I run it natively.
>>> Nevertheless, when the program is run via xming server, the error rate
>>> is almost 100%
>>> libopenssl 1.0.0-6.7.1 - x86_64
>>>
>>> #0  0x00007ffff5aca9e5 in raise () from /lib64/libc.so.6
>>> #1  0x00007ffff5acbee6 in abort () from /lib64/libc.so.6
>>> #2  0x00007ffff5b05c53 in __libc_message () from /lib64/libc.so.6
>>> #3  0x00007ffff5b0b226 in malloc_printerr () from /lib64/libc.so.6
>>> #4  0x00007ffff5b0e8e3 in _int_realloc () from /lib64/libc.so.6
>>> #5  0x00007ffff5b10142 in realloc () from /lib64/libc.so.6
>>> #6  0x00007ffff4ca6d4f in CRYPTO_realloc () from
>>> /lib64/libcrypto.so.1.0.0
>>> #7  0x00007ffff4d0d2a8 in lh_insert () from /lib64/libcrypto.so.1.0.0
>>> #8  0x00007ffff4ca980c in OBJ_NAME_add () from /lib64/libcrypto.so.1.0.0
>>> #9  0x00007ffff4d1a66b in OpenSSL_add_all_digests () from
>>> /lib64/libcrypto.so.1.0.0
>>> #10 0x00007ffff7bac3cc in ssh_crypto_init () at
>>> /home/paulo/Downloads/oss-src/libssh-0.4.8/libssh/dh.c:144
>>> #11 0x00007ffff7bae8f1 in ssh_init () at
>>> /home/paulo/Downloads/oss-src/libssh-0.4.8/libssh/init.c:47
>>> #12 0x00007ffff7ba929c in ssh_connect (session=0xc3b8e0)
>>>
>>> If I compile it against libgcrypt, it fails all the time due to an
>>> assertion failure --  ath.c:193: _gcry_ath_mutex_lock: Assertion `*lock
>>> == ((ath_mutex_t) 0)' failed.
>>> libgcrypt  1.4.4-6.1 - x86-64
>>>
>>> #0  0x00007ffff5ac79e5 in raise () from /lib64/libc.so.6
>>> #1  0x00007ffff5ac8ee6 in abort () from /lib64/libc.so.6
>>> #2  0x00007ffff4fdcaa8 in ?? () from /lib64/libgcrypt.so.11
>>> #3  0x00007ffff4fdd1c7 in ?? () from /lib64/libgcrypt.so.11
>>> #4  0x00007ffff4fd75f6 in ?? () from /lib64/libgcrypt.so.11
>>> #5  0x00007ffff4fd7792 in ?? () from /lib64/libgcrypt.so.11
>>> #6  0x00007ffff7ba8f7b in ssh_crypto_init ()
>>>     at /home/paulo/Downloads/oss-src/libssh-0.4.8/libssh/dh.c:115
>>> #7  0x00007ffff7bab961 in ssh_init ()
>>>     at /home/paulo/Downloads/oss-src/libssh-0.4.8/libssh/init.c:47
>>> #8  0x00007ffff7ba5ebc in ssh_connect (session=0xccf260)
>>>     at /home/paulo/Downloads/oss-src/libssh-0.4.8/libssh/client.c:516
>>>
>>> Am I missing any steps?? Is openSSL the best library to compile with??
>>>
>>> Any idea is appreciated.
>>>
>>> Regards,
>>>
>>> Paulo.
>>>
>>>
>>
>