Re: OpenLDAP API -- ldap_unbind SIGPIPE

["Kurt D. Zeilenga" <Kurt@OpenLDAP.org>]

I concur with Igor here regarding the library signal
handling issue (which is an OpenLDAP development issue*).
Libraries should not muck with signal handlers.

        Kurt


*  Software use questions, including those regarding
   use of APIs, belong on openldap-software list.


At 09:00 AM 2002-04-03, Igor Brezac wrote:

>Kervin,
>
>I do not think that this is a bug because the socket can brake between the
>test and the write() call.  I tried several different ldap libs and they
>behave the same in this particular example.  The application needs to take
>care of this with something simple like signal(SIGPIPE, SIG_IGN).
>
>-Igor
>
>On Wed, 3 Apr 2002, Kervin Pierre wrote:
>
>> hi,
>>
>> Thanks for the follow-up.
>>
>> I think this is a bug.  The ldap_unbind code should check that the
>> socket is still writeable before trying to write to it ( maybe using
>> fstat(2) ??)
>>
>> --Kervin
>>
>>
>> Igor Brezac wrote:
>> > Pierre,
>> >
>> > I figured it out.  The os is raising SIGPIPE (write() to a broken socket)
>> > and by default it terminates the program.  I just needed to ignore the
>> > signal or write a special handler for it.  Thanks for you help...
>> >
>> > -Igor
>> >
>> > On Tue, 2 Apr 2002, Igor Brezac wrote:
>> >
>> >
>> >>I do not have gdb, but adb is available.  I do not get core dump in this
>> >>example.  The following is the output:
>> >>
>> >># ./a.out
>> >>ldap_search_st() error Can't contact LDAP server
>> >>Broken Pipe
>> >>
>> >>I do not expect "Broken Pipe".  I traced it to ldap_send_unbind()
>> >>call in libldap.so.
>> >>
>> >>I added
>> >>debug = 0x00028;
>> >>ldap_set_option(NULL, LDAP_OPT_DEBUG_LEVEL, &(debug));
>> >>after ldap_initialize() call and I get the following output.
>> >>
>> >># ./a.out
>> >>request 1 done
>> >>ber_get_next failed.
>> >>LDAP: Can't contact LDAP server
>> >>Broken Pipe
>> >>
>> >>I hope that this will help.
>> >>
>> >>-Igor
>> >>
>> >>On Tue, 2 Apr 2002, Kervin Pierre wrote:
>> >>
>> >>
>> >>>Do you have gdb installed? How about a full backtrace on the core file.
>> >>>
>> >>>Igor Brezac wrote:
>> >>>
>> >>>>Hello,
>> >>>>
>> >>>>I tried to send this message to openldap-software, but I did not have
>> >>>>much luck there.  So, maybe some of you guys may be able to help me.
>> >>>>
>> >>>>I use Solaris 8 and openldap 2.0.23.  The following short program crashes
>> >>>>on the ldap_unbind() call.  I tried various different versions of this
>> >>>>program without success.  Am I doing something wrong here?
>> >>>>
>> >>>>Your help will be greatly appreciated.
>> >>>>
>> >>>>-Igor
>> >>>>
>> >>>>#include        <sys/types.h>
>> >>>>#include        <stdlib.h>
>> >>>>
>> >>>>#include        <lber.h>
>> >>>>#include        <ldap.h>
>> >>>>
>> >>>>int main() {
>> >>>>
>> >>>>        int rc;
>> >>>>        LDAP   *ldi;
>> >>>>        struct timeval tv;
>> >>>>        LDAPMessage *res = NULL;
>> >>>>        LDAPMessage *msg = NULL;
>> >>>>        char *dn;
>> >>>>        char *server = "ldap://10.1.1.197/";;
>> >>>>        char *base_dn = "o=pb";
>> >>>>        char *filter = "uid=igor";
>> >>>>        char *attrs[] = {"dn",NULL};
>> >>>>
>> >>>>
>> >>>>        rc = ldap_initialize(&ldi, server);
>> >>>>        if (rc != LDAP_SUCCESS) {
>> >>>>                exit (2);
>> >>>>        }
>> >>>>
>> >>>>        rc = ldap_simple_bind_s(ldi, "", "");
>> >>>>        if (rc != LDAP_SUCCESS) {
>> >>>>                exit (2);
>> >>>>        }
>> >>>>
>> >>>>//  If the ldap server is no longer available at this point
>> >>>>
>> >>>>        tv.tv_sec = 5;
>> >>>>        tv.tv_usec = 0;
>> >>>>        rc = ldap_search_st(ldi, base_dn, LDAP_SCOPE_SUBTREE, filter,
>> >>>>                        (char **) attrs, 0, &tv, &res);
>> >>>>
>> >>>>        if (rc != LDAP_SUCCESS) {
>> >>>>                ldap_get_option(ldi, LDAP_OPT_ERROR_NUMBER, &rc);
>> >>>>                printf("ldap_search_st() error %s\n", ldap_err2string(rc));
>> >>>>                ldap_msgfree(res);
>> >>>>                ldap_unbind(ldi);
>> >>>>
>> >>>>// ldap_unbind will cause a dump here
>> >>>>
>> >>>>                exit(2);
>> >>>>        }
>> >>>>
>> >>>>        msg = ldap_first_entry(ldi, res);
>> >>>>        dn = ldap_get_dn(ldi, msg);
>> >>>>        printf("DN: %s\n", dn);
>> >>>>
>> >>>>        ldap_msgfree(msg);
>> >>>>        free(dn);
>> >>>>        ldap_unbind_s(ldi);
>> >>>>        exit (1);
>> >>>>}
>> >>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>
>> >>>
>> >>>
>> >>>
>> >>
>> >
>> >
>> >
>>
>>
>>
>>