#ident "ldclt @(#)scalab01.c    1.8 01/05/03"

/** BEGIN COPYRIGHT BLOCK
 * Copyright (C) 2001 Sun Microsystems, Inc. Used by permission.
 * Copyright (C) 2021 Red Hat, Inc.
 * All rights reserved.
 *
 * License: GPL (version 3 or any later version).
 * See LICENSE for details.
 * END COPYRIGHT BLOCK **/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif


/*
    FILE :        scalab01.c
    AUTHOR :    Jean-Luc SCHWING
    VERSION :       1.0
    DATE :        08 January 2001
    DESCRIPTION :
            This file contains the implmentation of the specific
            scenario scalab01 of ldclt.
            I implement this set of functions in a separate file to
            reduce the interconnection(s) between the main ldclt
            and the add-ons, keeping in mind the possibility to use
            a dynamic load of plugins for a future release.
    LOCAL :        None.
    HISTORY :
---------+--------------+------------------------------------------------------
dd/mm/yy | Author    | Comments
---------+--------------+------------------------------------------------------
08/01/01 | JL Schwing    | Creation
---------+--------------+------------------------------------------------------
12/01/01 | JL Schwing    | 1.2 : Second set of options for -e scalab01
---------+--------------+------------------------------------------------------
29/01/01 | B Kolics    | 1.3 : readAttrValue() uses filter of requested attr
---------+--------------+------------------------------------------------------
01/02/01 | JL Schwing    | 1.4 : Protect against multiple choice of same user.
---------+--------------+------------------------------------------------------
26/02/01 | JL Schwing    | 1.5 : Port on non-solaris platforms...
---------+--------------+------------------------------------------------------
14/03/01 | JL Schwing    | 1.6 : Lint cleanup.
            | Bug fix : forget to set ldap protocol version.
---------+--------------+------------------------------------------------------
26/04/01 | B Kolics     | 1.7 : in case of lock failure, thread is not aborted
---------+--------------+------------------------------------------------------
03/05/01 | B Kolics     | 1.8 : bug fix - forget to release more line.
---------+--------------+------------------------------------------------------
*/


#include <stdio.h>   /* printf(), etc... */
#include <stdlib.h>  /* malloc(), etc... */
#include <string.h>  /* strcpy(), etc... */
#include <errno.h>   /* perror(), etc... */
#include <pthread.h> /* pthreads(), etc... */

#include <lber.h> /* ldap C-API BER declarations */
#include <ldap.h> /* ldap C-API declarations */
#include <prprf.h>
#include "port.h"     /* Portability definitions */
#include "ldclt.h"    /* This tool's include file */
#include "utils.h"    /* Utilities functions */
#include "scalab01.h" /* Scalab01 specific definitions */


/*
 * Private data structures.
 */
scalab01_context s1ctx;


/* ****************************************************************************
    FUNCTION :    scalab01_init
    PURPOSE :    Initiates the scalab01 scenario.
    INPUT :        None.
    OUTPUT :    None.
    RETURN :    -1 if error, 0 else.
    DESCRIPTION :
 *****************************************************************************/
int
scalab01_init(void)
{
    int ret; /* Return value */

    s1ctx.nbcnx = 0;      /* No connection yet */
    s1ctx.list = NULL;    /* No record yet */
    s1ctx.lockingMax = 0; /* No locking yet */

    /*
   * Initiates mutexes
   */
    if ((ret = ldclt_mutex_init(&(s1ctx.list_mutex))) != 0) {
        fprintf(stderr, "ldclt[%d]: %s\n", mctx.pid, strerror(ret));
        fprintf(stderr, "ldclt[%d]: Error: cannot initiate s1ctx.list_mutex\n", mctx.pid);
        fflush(stderr);
        return (-1);
    }
    if ((ret = ldclt_mutex_init(&(s1ctx.locking_mutex))) != 0) {
        fprintf(stderr, "ldclt[%d]: %s\n", mctx.pid, strerror(ret));
        fprintf(stderr, "ldclt[%d]: Error: cannot initiate s1ctx.locking_mutex\n", mctx.pid);
        fflush(stderr);
        return (-1);
    }
    if ((ret = ldclt_mutex_init(&(s1ctx.nbcnx_mutex))) != 0) {
        fprintf(stderr, "ldclt[%d]: %s\n", mctx.pid, strerror(ret));
        fprintf(stderr, "ldclt[%d]: Error: cannot initiate s1ctx.nbcnx_mutex\n", mctx.pid);
        fflush(stderr);
        return (-1);
    }

    /*
   * No error
   */
    return (0);
}


/* ****************************************************************************
    FUNCTION :    scalab01Lock
    PURPOSE :    Lock for single user trying to connect.
    INPUT :        tttctx    = thread context.
    OUTPUT :    None.
    RETURN :    -1 if error, 0 cannot lock, 1 if could lock.
    DESCRIPTION :
 *****************************************************************************/
int
scalab01Lock(
    thread_context *tttctx)
{
    int i;   /* For the loop */
    int ret; /* Return code */
    int res; /* Result of this function */

    /*
   * Get secure access to the common data structure.
   */
    if ((ret = ldclt_mutex_lock(&(s1ctx.locking_mutex))) != 0) {
        fprintf(stderr, "ldclt[%d]: %s: cannot mutex_lock(), error=%d (%s)\n",
                mctx.pid, tttctx->thrdId, ret, strerror(ret));
        fflush(stderr);
        return (-1);
    }

    /*
   * Is it locked ?
   */
    res = 1;
    for (i = 0; i < s1ctx.lockingMax; i++)
        if ((s1ctx.locking[i] != NULL) &&
            (!strcmp(s1ctx.locking[i], tttctx->bufBindDN))) {
            res = 0;
            break;
        }
    if (res == 1) {
        for (i = 0; (i < s1ctx.lockingMax) && (s1ctx.locking[i] != NULL); i++)
            ;
        if (i == s1ctx.lockingMax) {
            if (s1ctx.lockingMax == SCALAB01_MAX_LOCKING)
                res = 0;
            else
                s1ctx.lockingMax++;
        }
        if (res != 0)
            s1ctx.locking[i] = tttctx->bufBindDN;
    }

    /*
   * Free mutex
   */
    if ((ret = ldclt_mutex_unlock(&(s1ctx.locking_mutex))) != 0) {
        fprintf(stderr, "ldclt[%d]: %s: cannot mutex_unlock(), error=%d (%s)\n",
                mctx.pid, tttctx->thrdId, ret, strerror(ret));
        fflush(stderr);
        return (-1);
    }

    return (res);
}


/* ****************************************************************************
    FUNCTION :    scalab01Unlock
    PURPOSE :    Unlock for single user trying to connect.
    INPUT :        tttctx    = thread context.
    OUTPUT :    None.
    RETURN :    -1 if error, 0 else.
    DESCRIPTION :
 *****************************************************************************/
int
scalab01Unlock(
    thread_context *tttctx)
{
    int i;   /* For the loop */
    int ret; /* Return code */

    /*
   * Get secure access to the common data structure.
   */
    if ((ret = ldclt_mutex_lock(&(s1ctx.locking_mutex))) != 0) {
        fprintf(stderr, "ldclt[%d]: %s: cannot mutex_lock(), error=%d (%s)\n",
                mctx.pid, tttctx->thrdId, ret, strerror(ret));
        fflush(stderr);
        return (-1);
    }

    /*
   * Find the entry and unlock it.
   */
    for (i = 0; i < s1ctx.lockingMax; i++)
        if ((s1ctx.locking[i] != NULL) &&
            (!strcmp(s1ctx.locking[i], tttctx->bufBindDN))) {
            s1ctx.locking[i] = NULL;
            break;
        }

    /*
   * Free mutex
   */
    if ((ret = ldclt_mutex_unlock(&(s1ctx.locking_mutex))) != 0) {
        fprintf(stderr, "ldclt[%d]: %s: cannot mutex_unlock(), error=%d (%s)\n",
                mctx.pid, tttctx->thrdId, ret, strerror(ret));
        fflush(stderr);
        return (-1);
    }

    return (0);
}


/* ****************************************************************************
    FUNCTION :    scalab01_modemIncr
    PURPOSE :    Increments the modem nb of cnx
    INPUT :        ident    = thread identifier
    OUTPUT :    None.
    RETURN :    -1 if error
             0 if no modem available
             1 if modem available
    DESCRIPTION :
 *****************************************************************************/
int
scalab01_modemIncr(
    char *ident)
{
    int ret; /* Return value */
    int res; /* Result of this function */

    /*
   * Get secure access to the common data structure.
   */
    if ((ret = ldclt_mutex_lock(&(s1ctx.nbcnx_mutex))) != 0) {
        fprintf(stderr, "ldclt[%d]: %s: cannot mutex_lock(), error=%d (%s)\n",
                mctx.pid, ident, ret, strerror(ret));
        fflush(stderr);
        return (-1);
    }

    if (s1ctx.nbcnx >= s1ctx.maxcnxnb)
        res = 0;
    else {
        res = 1;
        s1ctx.nbcnx++;
    }

    /*
   * Free mutex
   */
    if ((ret = ldclt_mutex_unlock(&(s1ctx.nbcnx_mutex))) != 0) {
        fprintf(stderr, "ldclt[%d]: %s: cannot mutex_unlock(), error=%d (%s)\n",
                mctx.pid, ident, ret, strerror(ret));
        fflush(stderr);
        return (-1);
    }

    return (res);
}


/* ****************************************************************************
    FUNCTION :    scalab01_modemDecr
    PURPOSE :    Decrements the modem nb of cnx
    INPUT :        ident    = thread identifier
    OUTPUT :    None.
    RETURN :    -1 if error, 0 else.
    DESCRIPTION :
 *****************************************************************************/
int
scalab01_modemDecr(
    char *ident)
{
    int ret; /* Return value */

    /*
   * Get secure access to the common data structure.
   */
    if ((ret = ldclt_mutex_lock(&(s1ctx.nbcnx_mutex))) != 0) {
        fprintf(stderr, "ldclt[%d]: %s: cannot mutex_lock(), error=%d (%s)\n",
                mctx.pid, ident, ret, strerror(ret));
        fflush(stderr);
        return (-1);
    }

    s1ctx.nbcnx--;

    /*
   * Free mutex
   */
    if ((ret = ldclt_mutex_unlock(&(s1ctx.nbcnx_mutex))) != 0) {
        fprintf(stderr, "ldclt[%d]: %s: cannot mutex_unlock(), error=%d (%s)\n",
                mctx.pid, ident, ret, strerror(ret));
        fflush(stderr);
        return (-1);
    }

    return (0);
}


/* ****************************************************************************
    FUNCTION :    scalab01_addLogin
    PURPOSE :    Add a new user login to the s1ctx structure.
    INPUT :        tttctx     = thread context.
            dn     = user's dn.
            duration = duration of the connection.
    OUTPUT :    None.
    RETURN :    -1 if error, 0 else.
    DESCRIPTION :
 *****************************************************************************/
int
scalab01_addLogin(
    thread_context *tttctx,
    char *dn,
    int duration)
{
    int ret;       /* Return value */
    isp_user *new; /* New entry */
    isp_user **ptcur; /* Current entry address */
    int rc = 0;

    /*
   * Create the new record.
   */
    new = (isp_user *)malloc(sizeof(isp_user));
    if (NULL == new) {
        fprintf(stderr, "ldclt[%d]: %s: cannot malloc(isp_user), error=%d (%s)\n",
                mctx.pid, tttctx->thrdId, errno, strerror(errno));
        fflush(stderr);
        return -1;
    }

    strncpy(new->dn, dn, sizeof(new->dn));
    new->dn[sizeof(new->dn) - 1] = '\0';
    new->cost = new->counter = duration;
    new->next = NULL;

    /*
   * Get secure access to the common data structure.
   * Note : it should be possible to reduce the "size" of this critical
   *        section but I am not 100% certain this won't mess up all things.
   */
    if ((ret = ldclt_mutex_lock(&(s1ctx.list_mutex))) != 0) {
        fprintf(stderr, "ldclt[%d]: %s: cannot mutex_lock(), error=%d (%s)\n",
                mctx.pid, tttctx->thrdId, ret, strerror(ret));
        fflush(stderr);
        rc = -1;
        goto error;
    }

    /* 
     * Find insertion point
     */
    ptcur = &s1ctx.list;
    while ((*ptcur != NULL) && ((*ptcur)->counter < duration)) {
        ptcur = &(*ptcur)->next;
    }
    /*
     * Insert new element
     */
    new->next = *ptcur;
    *ptcur = new;
    new = NULL;

error:
    if (new)
        free(new);

    /*
   * Free mutex
   */
    if ((ret = ldclt_mutex_unlock(&(s1ctx.list_mutex))) != 0) {
        fprintf(stderr, "ldclt[%d]: %s: cannot mutex_unlock(), error=%d (%s)\n",
                mctx.pid, tttctx->thrdId, ret, strerror(ret));
        fflush(stderr);
        rc = -1;
    }

    return rc;
}


/* ****************************************************************************
    FUNCTION :    scalab01_connectSuperuser
    PURPOSE :    Purpose of the fct
    INPUT :        None.
    OUTPUT :    None.
    RETURN :    -1 if error, 0 else.
    DESCRIPTION :
 *****************************************************************************/
int
scalab01_connectSuperuser(void)
{
    char bindDN[MAX_DN_LENGTH] = {0}; /* To bind */
    unsigned int mode = mctx.mode;
    unsigned int mod2 = mctx.mod2;

    if (!(mode & CLTAUTH)) {
        snprintf(bindDN, sizeof(bindDN), "%s,%s", SCALAB01_SUPER_USER_RDN, mctx.baseDN);
        bindDN[sizeof(bindDN) - 1] = '\0';
    }
    /* clear bits not applicable to this mode */
    mod2 &= ~M2_RNDBINDFILE;
    mod2 &= ~M2_SASLAUTH;
    mod2 &= ~M2_RANDOM_SASLAUTHID;
    /* force bind to happen */
    mode |= BIND_EACH_OPER;
    s1ctx.ldapCtx = connectToLDAP(NULL, bindDN, SCALAB01_SUPER_USER_PASSWORD, mode, mod2);
    if (!s1ctx.ldapCtx) {
        return (-1);
    }

    /*
   * Normal end...
   */
    return (0);
}


/* ****************************************************************************
    FUNCTION :    readAttrValue
    PURPOSE :    This function will ldap_search the given entry for the
            value of the given attribute.
    INPUT :        ident    = thread identifier
            ldapCtx    = LDAP context
            dn    = dn of the entry to process
            attname    = attribute name
    OUTPUT :    value    = attribute value. This buffer must be
                  initiated with enough memory.
                  value[0] == '\0' if not find.
    RETURN :    -1 if error, 0 else.
    DESCRIPTION :
 *****************************************************************************/
int
readAttrValue(
    LDAP *ldapCtx,
    char *ident,
    char *dn,
    char *attname,
    char *value)
{
    int ret;          /* Return value */
    char *attrs[2];   /* Attribute to retrieve */
    LDAPMessage *res; /* LDAP responses */
    LDAPMessage *cur; /* Current message */
    BerElement *ber;  /* To decode the response */
    char *aname;      /* Current attribute name */
    char *filter;     /* Filter used for searching */

    /*
     * First, ldap_search() the entry.
     */
    attrs[0] = attname;
    attrs[1] = NULL;

    filter = PR_smprintf("(%s=*)", attname);
    ret = ldap_search_ext_s(ldapCtx, dn, LDAP_SCOPE_BASE,
                            filter, attrs, 0, NULL, NULL, NULL, -1, &res);
    free(filter);
    if (ret != LDAP_SUCCESS) {
        printf("ldclt[%d]: %s: Cannot ldap_search (%s in %s), error=%d (%s)\n",
               mctx.pid, ident, attname, dn, ret, my_ldap_err2string(ret));
        fflush(stdout);
        return (-1);
    }

    /*
   * Decode the response
   */
    value[0] = '\0'; /* Not find yet */
    cur = ldap_first_entry(ldapCtx, res);
    while ((!value[0]) && (cur != NULL)) {
        aname = ldap_first_attribute(ldapCtx, cur, &ber);
        while ((!value[0]) && (aname != NULL)) {
            /*
       * We expect this attribute to be single-valued.
       */
            if (!strcmp(aname, attname)) {
                struct berval **vals;
                vals = ldap_get_values_len(ldapCtx, cur, aname);
                if (vals == NULL) {
                    printf("ldclt[%d]: %s: no value for %s in %s\n",
                           mctx.pid, ident, dn, attname);
                    fflush(stdout);
                    return (-1);
                }
                strncpy(value, vals[0]->bv_val, vals[0]->bv_len);
                value[vals[0]->bv_len] = '\0';
                ldap_value_free_len(vals);
            }

            /*
       * Next attribute
       */
            ldap_memfree(aname);
            if (!value[0])
                aname = ldap_next_attribute(ldapCtx, cur, ber);
        }

        /*
     * Next entry - shouldn't happen in theory
     */
        if (ber != NULL)
            ber_free(ber, 0);
        cur = ldap_next_entry(ldapCtx, cur);
    }
    ldap_msgfree(res); /* Free the response */

    return (0);
}


/* ****************************************************************************
    FUNCTION :    writeAttrValue
    PURPOSE :    This function will ldap_modify the given entry to
            replace the value of the given attribute.
    INPUT :        ident    = thread identifier
            ldapCtx    = LDAP context
            dn    = dn of the entry to process
            attname    = attribute name
            value    = attribute value
    OUTPUT :    None.
    RETURN :    -1 if error, 0 else.
    DESCRIPTION :
 *****************************************************************************/
int
writeAttrValue(
    LDAP *ldapCtx,
    char *ident,
    char *dn,
    char *attname,
    char *value)
{
    int ret;              /* Return value */
    LDAPMod attr;         /* To build the attributes */
    LDAPMod *attrsmod[2]; /* Modify attributes */
    char *pvalues[2];     /* To build the values list */

    /*
   * Prepear the data to be written
   */
    pvalues[0] = value;
    pvalues[1] = NULL;
    attr.mod_op = LDAP_MOD_REPLACE;
    attr.mod_type = attname;
    attr.mod_values = pvalues;
    attrsmod[0] = &attr;
    attrsmod[1] = NULL;

    /*
   * Store the data in the directory.
   */
    ret = ldap_modify_ext_s(ldapCtx, dn, attrsmod, NULL, NULL);
    if (ret != LDAP_SUCCESS) {
        printf("ldclt[%d]: %s: Cannot ldap_modify_ext_s (%s in %s), error=%d (%s)\n",
               mctx.pid, ident, attname, dn, ret, my_ldap_err2string(ret));
        fflush(stdout);
        return (-1);
    }

    return (0);
}


/* ****************************************************************************
    FUNCTION :    scalab01_unlock
    PURPOSE :    Unlock the user given in argument.
    INPUT :        entry    = entry to unlock.
    OUTPUT :    None.
    RETURN :    -1 if error, 0 else.
    DESCRIPTION :
 *****************************************************************************/
int
scalab01_unlock(
    isp_user *user)
{
    int account;  /* Accounting value */
    char buf[20]; /* To read/write attribute */

    /*
   * Increment accounting counters
   * First, read the current value.
   */
    if (readAttrValue(s1ctx.ldapCtx, "ctrl", user->dn, SCALAB01_ACC_ATTRIB, buf) < 0) {
        printf("ldclt[%d]: ctrl: Cannot read accounting attribute of %s\n",
               mctx.pid, user->dn);
        fflush(stdout);
        return (-1);
    }

    /*
   * If this attribute has no value (doesn't exist) we assume it is 0.
   */
    if (buf[0] != '\0')
        account = atoi(buf);
    else {
        printf("ldclt[%d]: ctrl: No accounting attribute for %s - assume it is 0\n",
               mctx.pid, user->dn);
        fflush(stdout);
        account = 0;
    }

    /*
   * Compute the new value and store it in the directory.
   */
    sprintf(buf, "%d", account + user->cost);
    if (writeAttrValue(s1ctx.ldapCtx, "ctrl", user->dn, SCALAB01_ACC_ATTRIB, buf) < 0) {
        printf("ldclt[%d]: ctrl: Cannot write accounting attribute of %s\n",
               mctx.pid, user->dn);
        fflush(stdout);
        return (-1);
    }

    /*
   * Unlock the user
   */
    if (writeAttrValue(s1ctx.ldapCtx, "ctrl", user->dn,
                       SCALAB01_LOCK_ATTRIB, SCALAB01_VAL_UNLOCKED) < 0) {
        printf("ldclt[%d]: ctrl: Cannot write lock (unlock) attribute of %s\n",
               mctx.pid, user->dn);
        fflush(stdout);
        return (-1);
    }
    if (mctx.mode & VERY_VERBOSE)
        printf("ldclt[%d]: ctrl: entry %s unlocked\n",
               mctx.pid, user->dn);

    /*
   * Decrement modem pool usage...
   */
    if (scalab01_modemDecr("ctrl") < 0)
        return (-1);

    /*
   * Normal end
   */
    return (0);
}


/* ****************************************************************************
    FUNCTION :    scalab01_control
    PURPOSE :    This function implements the control loop/thread of
            the scalab01 scenario. Its main target is to manage
            the counters of each "connection" and to unlock the
            entry when time is reached.
    INPUT :        None.
    OUTPUT :    None.
    RETURN :    -1 if error, 0 else.
    DESCRIPTION :
 *****************************************************************************/
void *
scalab01_control(
    void *arg __attribute__((unused)))
{
    isp_user *cur;  /* Current entry */
    isp_user *head; /* Head of entries to process */
    int ret;        /* Return value */
    int nbTot;      /* Total nb entries locked */
    int nbU;        /* Number unlocked */

    /*
   * Initialization
   * Failure to connect is a critical error...
   */
    if (scalab01_connectSuperuser() < 0)
        ldcltExit(EXIT_NOBIND);

    /*
   * Main loop
   */
    while (1 /*CONSTCOND*/) /*JLS 14-03-01*/
    {
        ldclt_sleep(1);  /* Poll the connections every second */
        nbTot = nbU = 0; /* No entries processed yet */

        /*
     * Get protected access to the entries
     */
        if ((ret = ldclt_mutex_lock(&(s1ctx.list_mutex))) != 0) {
            fprintf(stderr, "ldclt[%d]: ctrl: cannot mutex_lock(), error=%d (%s)\n",
                    mctx.pid, ret, strerror(ret));
            fflush(stderr);
            ldcltExit(EXIT_OTHER);
        }

        /*
     * Decrement all counters
     */
        for (cur = s1ctx.list; cur != NULL; cur = cur->next) {
            cur->counter--;
            nbTot++;
        }

        /*
     * Find the entries to process.
     */
        if ((s1ctx.list == NULL) || (s1ctx.list->counter > 0))
            head = NULL;
        else {
            head = cur = s1ctx.list;
            while ((cur != NULL) && (cur->counter == 0))
                cur = cur->next;
            s1ctx.list = cur;
        }

        /*
     * Release mutex
     */
        if ((ret = ldclt_mutex_unlock(&(s1ctx.list_mutex))) != 0) {
            fprintf(stderr, "ldclt[%d]: ctrl: cannot mutex_unlock(), error=%d (%s)\n",
                    mctx.pid, ret, strerror(ret));
            fflush(stderr);
            ldcltExit(EXIT_OTHER);
        }

        /*
     * Now, we have "head" that points either to NULL or to a list of
     * entries to process.
     * Attention, this list of entries is not terminated by NULL, but
     * we must rather check the field head->next->counter" for the last
     * entry...
     *
     * NOTE : implements this section as a separate thread to keep the
     *        general timer working...
     */
        while (head != NULL) {
            if (scalab01_unlock(head) < 0) {
                printf("ldclt[%d]: ctrl: cannot unlock %s\n", mctx.pid, head->dn);
                ldcltExit(EXIT_OTHER);
            }
            nbU++; /* One more entry unlocked */

            /*
       * Next entry...
       */
            cur = head;
            if (head->next == NULL)
                head = NULL;
            else if (head->next->counter != 0)
                head = NULL;
            else
                head = head->next;

            free(cur);
        } /* while (head =! NULL) */

        /*
     * Print some stats...
     */
        if (mctx.mode & VERBOSE)
            printf("ldclt[%d]: ctrl: nb entries unlocked / total : %3d / %5d\n",
                   mctx.pid, nbU, nbTot);
    } /* Main loop */

    /*
   * End of thread
   */
}


/* ****************************************************************************
    FUNCTION :    doScalab01
    PURPOSE :    Implements the client part of the scalab01 scenario.
    INPUT :        tttctx    = this thread context
    OUTPUT :    None.
    RETURN :    -1 if error, 0 else.
    DESCRIPTION :
 *****************************************************************************/
int
doScalab01(
    thread_context *tttctx)
{
    char buf[32]; /* To read attributes value */
    int duration; /* Use a variable for trace purpose */
    int res;      /* Result of cnx to modem pool */
    int doloop;   /* To know if we should loop */

    /*
   * Simulate connection to the modem pool.
   */
    while ((res = scalab01_modemIncr(tttctx->thrdId)) != 1)
        switch (res) {
        case 0:
            ldclt_sleep(s1ctx.wait == 0 ? SCALAB01_DEF_WAIT_TIME : rndlim(0, s1ctx.wait));
            break;
        case -1:
            return (-1);
            break;
        }

    /*
   * Connection to the server
   * The function connectToServer() will take care of the various connection/
   * disconnection, bind/unbind/close etc... requested by the user.
   * The cost is one more function call in this application, but the
   * resulting source code will be much more easiest to maintain.
   */
    if (connectToServer(tttctx) < 0)
        return (-1);
    if (!(tttctx->binded))
        return (0);

    /*
   * Check that no other thread is using the same identity...
   */
    doloop = 1;
    while (doloop) {
        switch (scalab01Lock(tttctx)) {
        case 0:
            ldclt_sleep(1);
            break;
        case 1:
            doloop = 0;
            break;
        case -1:
            return (-1);
            break;
        }
    }

    /*
   * Ok, we are now binded. Great ;-)
   * The DN we used to bind is available in tttctx->bufBindDN
   * Read lock attribute
   */
    if (readAttrValue(tttctx->ldapCtx, tttctx->thrdId, tttctx->bufBindDN,
                      SCALAB01_LOCK_ATTRIB, buf) < 0) {
        printf("ldclt[%d]: %s: Cannot read lock attribute of %s\n",
               mctx.pid, tttctx->thrdId, tttctx->bufBindDN);
        fflush(stdout);
        (void)scalab01_modemDecr(tttctx->thrdId);
        return (-1);
    }
    if (mctx.mode & VERY_VERBOSE)
        printf("ldclt[%d]: %s: entry %s lock read\n",
               mctx.pid, tttctx->thrdId, tttctx->bufBindDN);

    /*
   * If locked, then we cannot login now...
   */
    if (!strcmp(buf, SCALAB01_VAL_LOCKED)) {
        if (scalab01_modemDecr(tttctx->thrdId) < 0)
            return (-1);
        return (0);
    }

    /*
   * If not locked :
   *  - lock the user
   *  - decide how many times will be connected
   *  - add information to the list of connected
   */
    if (writeAttrValue(tttctx->ldapCtx, tttctx->thrdId, tttctx->bufBindDN,
                       SCALAB01_LOCK_ATTRIB, SCALAB01_VAL_LOCKED) < 0) {
        printf("ldclt[%d]: %s: Cannot write lock attribute of %s\n",
               mctx.pid, tttctx->thrdId, tttctx->bufBindDN);
        fflush(stdout);
        /*
     * It can still happen that two threads write this attribute at the same
     * time, so there can be failure in one of the threads
     * in this case just return
     */
        if (scalab01_modemDecr(tttctx->thrdId) < 0) /*JLS 03-05-01*/
            return (-1);                            /*JLS 03-05-01*/
        return (0);                                 /*BK  26-04-01*/
    }
    if (mctx.mode & VERY_VERBOSE)
        printf("ldclt[%d]: %s: entry %s lock written\n",
               mctx.pid, tttctx->thrdId, tttctx->bufBindDN);

    if (scalab01Unlock(tttctx) < 0)
        return (-1);

    duration = rndlim(1, s1ctx.cnxduration);
    if (scalab01_addLogin(tttctx, tttctx->bufBindDN, duration) < 0) {
        printf("ldclt[%d]: %s: Cannot memorize new login of %s\n",
               mctx.pid, tttctx->thrdId, tttctx->bufBindDN);
        fflush(stdout);
        return (-1);
    }
    if (mctx.mode & VERY_VERBOSE)
        printf("ldclt[%d]: %s: entry %s login added duration %6d\n",
               mctx.pid, tttctx->thrdId, tttctx->bufBindDN, duration);

    /*
   * Memorize the operation
   */
    if (incrementNbOpers(tttctx) < 0)
        return (-1);

    /*
   * Wait before next operation...
   */
    if (s1ctx.wait > 0)
        ldclt_sleep(rndlim(0, s1ctx.wait));

    /*
   * Unbind
   */
    /*
TBC - this is done in the next loop... - cf connectToServer()
*/

    return (0);
}
