xrdp-proprietary/sesman/session.c

/**
 * xrdp: A Remote Desktop Protocol server.
 *
 * Copyright (C) Jay Sorg 2004-2013
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 *
 * @file session.c
 * @brief Session management code
 * @author Jay Sorg, Simone Fedele
 *
 */

#include "sesman.h"
#include "libscp_types.h"

#include <errno.h>
//#include <time.h>

extern tbus g_sync_event;
extern unsigned char g_fixedkey[8];
extern struct config_sesman *g_cfg; /* in sesman.c */
extern int g_sck; /* in sesman.c */
extern int g_thread_sck; /* in thread.c */
struct session_chain *g_sessions;
int g_session_count;

static int g_sync_width;
static int g_sync_height;
static int g_sync_bpp;
static char *g_sync_username;
static char *g_sync_password;
static char *g_sync_domain;
static char *g_sync_program;
static char *g_sync_directory;
static char *g_sync_client_ip;
static tbus g_sync_data;
static tui8 g_sync_type;
static int g_sync_result;
static int g_sync_cmd;

/**
 * Creates a string consisting of all parameters that is hosted in the param list
 * @param self
 * @param outstr, allocate this buffer before you use this function
 * @param len the allocated len for outstr
 * @return
 */
char *APP_CC
dumpItemsToString(struct list *self, char *outstr, int len)
{
    int index;
    tbus item;
    int totalLen = 0;

    g_memset(outstr, 0, len);
    if (self->count == 0)
    {
        g_writeln("List is empty");
    }

    for (index = 0; index < self->count; index++)
    {
        /* +1 = one space*/
        totalLen = totalLen + g_strlen((char *)list_get_item(self, index)) + 1;

        if (len > totalLen)
        {
            g_strcat(outstr, (char *)list_get_item(self, index));
            g_strcat(outstr, " ");
        }
    }

    return outstr ;
}


/******************************************************************************/
struct session_item *DEFAULT_CC
session_get_bydata(char *name, int width, int height, int bpp, int type)
{
    struct session_chain *tmp;

    /*THREAD-FIX require chain lock */
    lock_chain_acquire();

    tmp = g_sessions;

    /* convert from SCP_SESSION_TYPE namespace to SESMAN_SESSION_TYPE namespace */
    switch (type)
    {
        case SCP_SESSION_TYPE_XVNC: /* 0 */
            type = SESMAN_SESSION_TYPE_XVNC; /* 2 */
            break;
        case SCP_SESSION_TYPE_XRDP: /* 1 */
            type = SESMAN_SESSION_TYPE_XRDP; /* 1 */
            break;
        default:
            lock_chain_release();
            return 0;
    }

    while (tmp != 0)
    {
        if (type == SESMAN_SESSION_TYPE_XRDP)
        {
            /* only name and bpp need to match for X11rdp, it can resize */
            if (g_strncmp(name, tmp->item->name, 255) == 0 &&
                    tmp->item->bpp == bpp &&
                    tmp->item->type == type)
            {
                /*THREAD-FIX release chain lock */
                lock_chain_release();
                return tmp->item;
            }
        }

        if (g_strncmp(name, tmp->item->name, 255) == 0 &&
                tmp->item->width == width &&
                tmp->item->height == height &&
                tmp->item->bpp == bpp &&
                tmp->item->type == type)
        {
            /*THREAD-FIX release chain lock */
            lock_chain_release();
            return tmp->item;
        }

        tmp = tmp->next;
    }

    /*THREAD-FIX release chain lock */
    lock_chain_release();
    return 0;
}

/******************************************************************************/
/**
 *
 * @brief checks if there's a server running on a display
 * @param display the display to check
 * @return 0 if there isn't a display running, nonzero otherwise
 *
 */
static int DEFAULT_CC
x_server_running_check_ports(int display)
{
    char text[256];
    int x_running;
    int sck;

    g_sprintf(text, "/tmp/.X11-unix/X%d", display);
    x_running = g_file_exist(text);

    if (!x_running)
    {
        g_sprintf(text, "/tmp/.X%d-lock", display);
        x_running = g_file_exist(text);
    }

    if (!x_running) /* check 59xx */
    {
        sck = g_tcp_socket();
        g_sprintf(text, "59%2.2d", display);
        x_running = g_tcp_bind(sck, text);
        g_tcp_close(sck);
    }

    if (!x_running) /* check 60xx */
    {
        sck = g_tcp_socket();
        g_sprintf(text, "60%2.2d", display);
        x_running = g_tcp_bind(sck, text);
        g_tcp_close(sck);
    }

    if (!x_running) /* check 62xx */
    {
        sck = g_tcp_socket();
        g_sprintf(text, "62%2.2d", display);
        x_running = g_tcp_bind(sck, text);
        g_tcp_close(sck);
    }

    return x_running;
}

/******************************************************************************/
/**
 *
 * @brief checks if there's a server running on a display
 * @param display the display to check
 * @return 0 if there isn't a display running, nonzero otherwise
 *
 */
static int DEFAULT_CC
x_server_running(int display)
{
    char text[256];
    int x_running;
    int sck;

    g_sprintf(text, "/tmp/.X11-unix/X%d", display);
    x_running = g_file_exist(text);

    if (!x_running)
    {
        g_sprintf(text, "/tmp/.X%d-lock", display);
        x_running = g_file_exist(text);
    }

    return x_running;
}

/******************************************************************************/
static void DEFAULT_CC
session_start_sessvc(int xpid, int wmpid, long data, char *username, int display)
{
    struct list *sessvc_params = (struct list *)NULL;
    char wmpid_str[25];
    char xpid_str[25];
    char exe_path[262];
    int i = 0;

    /* initialize (zero out) local variables: */
    g_memset(wmpid_str, 0, sizeof(char) * 25);
    g_memset(xpid_str, 0, sizeof(char) * 25);
    g_memset(exe_path, 0, sizeof(char) * 262);

    /* new style waiting for clients */
    g_sprintf(wmpid_str, "%d", wmpid);
    g_sprintf(xpid_str, "%d",  xpid);
    log_message(LOG_LEVEL_INFO,
                "starting xrdp-sessvc - xpid=%s - wmpid=%s",
                xpid_str, wmpid_str);

    sessvc_params = list_create();
    sessvc_params->auto_free = 1;

    /* building parameters */
    g_snprintf(exe_path, 261, "%s/xrdp-sessvc", XRDP_SBIN_PATH);

    list_add_item(sessvc_params, (long)g_strdup(exe_path));
    list_add_item(sessvc_params, (long)g_strdup(xpid_str));
    list_add_item(sessvc_params, (long)g_strdup(wmpid_str));
    list_add_item(sessvc_params, 0); /* mandatory */

    env_set_user(username, 0, display);

    /* executing sessvc */
    g_execvp(exe_path, ((char **)sessvc_params->items));

    /* should not get here */
    log_message(LOG_LEVEL_ALWAYS,
                "error starting xrdp-sessvc - pid %d - xpid=%s - wmpid=%s",
                g_getpid(), xpid_str, wmpid_str);

    /* logging parameters */
    /* no problem calling strerror for thread safety: other threads
       are blocked */
    log_message(LOG_LEVEL_DEBUG, "errno: %d, description: %s",
                errno, g_get_strerror());
    log_message(LOG_LEVEL_DEBUG, "execve parameter list:");

    for (i = 0; i < (sessvc_params->count); i++)
    {
        log_message(LOG_LEVEL_DEBUG, "        argv[%d] = %s", i,
                    (char *)list_get_item(sessvc_params, i));
    }

    list_delete(sessvc_params);

    /* keep the old waitpid if some error occurs during execlp */
    g_waitpid(wmpid);
    g_sigterm(xpid);
    g_sigterm(wmpid);
    g_sleep(1000);
    auth_end(data);
    g_exit(0);
}

/******************************************************************************/
/* called with the main thread
   returns boolean */
static int APP_CC
session_is_display_in_chain(int display)
{
    struct session_chain *chain;
    struct session_item *item;

    chain = g_sessions;

    while (chain != 0)
    {
        item = chain->item;

        if (item->display == display)
        {
            return 1;
        }

        chain = chain->next;
    }

    return 0;
}

/******************************************************************************/
/* called with the main thread */
static int APP_CC
session_get_aval_display_from_chain(void)
{
    int display;

    display = g_cfg->sess.x11_display_offset;
    lock_chain_acquire();

    while ((display - g_cfg->sess.x11_display_offset) <= g_cfg->sess.max_sessions)
    {
        if (!session_is_display_in_chain(display))
        {
            if (!x_server_running_check_ports(display))
            {
                lock_chain_release();
                return display;
            }
        }

        display++;
    }

    lock_chain_release();
    log_message(LOG_LEVEL_ERROR, "X server -- no display in range is available");
    return 0;
}

/******************************************************************************/
static int APP_CC
wait_for_xserver(int display)
{
    int i;

    /* give X a bit to start */
    /* wait up to 10 secs for x server to start */
    i = 0;

    while (!x_server_running(display))
    {
        i++;

        if (i > 40)
        {
            log_message(LOG_LEVEL_ERROR,
                        "X server for display %d startup timeout",
                        display);
            break;
        }

        g_sleep(250);
    }

    return 0;
}

/******************************************************************************/
/* called with the main thread */
static int APP_CC
session_start_fork(int width, int height, int bpp, char *username,
                   char *password, tbus data, tui8 type, char *domain,
                   char *program, char *directory, char *client_ip)
{
    int display = 0;
    int pid = 0;
    int wmpid = 0;
    int pampid = 0;
    int xpid = 0;
    int i = 0;
    char geometry[32];
    char depth[32];
    char screen[32];
    char text[256];
    char passwd_file[256];
    char **pp1 = (char **)NULL;
    struct session_chain *temp = (struct session_chain *)NULL;
    struct list *xserver_params = (struct list *)NULL;
    time_t ltime;
    struct tm stime;
    char execvpparams[2048];

    /* initialize (zero out) local variables: */
    g_memset(&ltime, 0, sizeof(time_t));
    g_memset(&stime, 0, sizeof(struct tm));
    g_memset(geometry, 0, sizeof(char) * 32);
    g_memset(depth, 0, sizeof(char) * 32);
    g_memset(screen, 0, sizeof(char) * 32);
    g_memset(text, 0, sizeof(char) * 256);
    g_memset(passwd_file, 0, sizeof(char) * 256);

    /* check to limit concurrent sessions */
    if (g_session_count >= g_cfg->sess.max_sessions)
    {
        log_message(LOG_LEVEL_INFO, "max concurrent session limit "
                    "exceeded. login for user %s denied", username);
        return 0;
    }

    temp = (struct session_chain *)g_malloc(sizeof(struct session_chain), 0);

    if (temp == 0)
    {
        log_message(LOG_LEVEL_ERROR, "cannot create new chain "
                    "element - user %s", username);
        return 0;
    }

    temp->item = (struct session_item *)g_malloc(sizeof(struct session_item), 0);

    if (temp->item == 0)
    {
        g_free(temp);
        log_message(LOG_LEVEL_ERROR, "cannot create new session "
                    "item - user %s", username);
        return 0;
    }

    display = session_get_aval_display_from_chain();

    if (display == 0)
    {
        g_free(temp->item);
        g_free(temp);
        return 0;
    }

    pid = g_fork();

    if (pid == -1)
    {
    }
    else if (pid == 0) /* child sesman */
    {
        g_tcp_close(g_sck);
        g_tcp_close(g_thread_sck);
        g_sprintf(geometry, "%dx%d", width, height);
        g_sprintf(depth, "%d", bpp);
        g_sprintf(screen, ":%d", display);
        wmpid = g_fork();
        if (wmpid == -1)
        {
        }
        else if (wmpid == 0) /* child (child sesman) xserver */
        {
            wait_for_xserver(display);
            auth_start_session(data, display);
            pampid = g_fork();
            if (pampid == -1)
            {
            }
            else if (pampid == 0) /* child: X11/client */
            {
                env_set_user(username, 0, display);
                if (x_server_running(display))
                {
                    auth_set_env(data);
                    if (directory != 0)
                    {
                        if (directory[0] != 0)
                        {
                            g_set_current_dir(directory);
                        }
                    }
                    if (program != 0)
                    {
                        if (program[0] != 0)
                        {
                            g_execlp3(program, program, 0);
                            log_message(LOG_LEVEL_ALWAYS,
                                        "error starting program %s for user %s - pid %d",
                                        program, username, g_getpid());
                        }
                    }
                    /* try to execute user window manager if enabled */
                    if (g_cfg->enable_user_wm)
                    {
                        g_sprintf(text, "%s/%s", g_getenv("HOME"), g_cfg->user_wm);
                        if (g_file_exist(text))
                        {
                            g_execlp3(text, g_cfg->user_wm, 0);
                            log_message(LOG_LEVEL_ALWAYS, "error starting user "
                                        "wm for user %s - pid %d", username, g_getpid());
                            /* logging parameters */
                            log_message(LOG_LEVEL_DEBUG, "errno: %d, "
                                        "description: %s", errno, g_get_strerror());
                            log_message(LOG_LEVEL_DEBUG, "execlp3 parameter "
                                        "list:");
                            log_message(LOG_LEVEL_DEBUG, "        argv[0] = %s",
                                        text);
                            log_message(LOG_LEVEL_DEBUG, "        argv[1] = %s",
                                        g_cfg->user_wm);
                        }
                    }
                    /* if we're here something happened to g_execlp3
                       so we try running the default window manager */
                    g_sprintf(text, "%s/%s", XRDP_CFG_PATH, g_cfg->default_wm);
                    g_execlp3(text, g_cfg->default_wm, 0);

                    log_message(LOG_LEVEL_ALWAYS, "error starting default "
                                 "wm for user %s - pid %d", username, g_getpid());
                    /* logging parameters */
                    log_message(LOG_LEVEL_DEBUG, "errno: %d, description: "
                                "%s", errno, g_get_strerror());
                    log_message(LOG_LEVEL_DEBUG, "execlp3 parameter list:");
                    log_message(LOG_LEVEL_DEBUG, "        argv[0] = %s",
                                text);
                    log_message(LOG_LEVEL_DEBUG, "        argv[1] = %s",
                                g_cfg->default_wm);

                    /* still a problem starting window manager just start xterm */
                    g_execlp3("xterm", "xterm", 0);

                    /* should not get here */
                    log_message(LOG_LEVEL_ALWAYS, "error starting xterm "
                                "for user %s - pid %d", username, g_getpid());
                    /* logging parameters */
                    log_message(LOG_LEVEL_DEBUG, "errno: %d, description: "
                                "%s", errno, g_get_strerror());
                }
                else
                {
                    log_message(LOG_LEVEL_ERROR, "another Xserver might "
                                "already be active on display %d - see log", display);
                }

                log_message(LOG_LEVEL_DEBUG, "aborting connection...");
                g_exit(0);
            }
            else
            {
                g_waitpid(pampid);
                auth_stop_session(data);
                g_deinit();
                g_exit(0);
            }
        }
        else /* parent (child sesman) */
        {
            xpid = g_fork();

            if (xpid == -1)
            {
            }
            else if (xpid == 0) /* child */
            {
                env_set_user(username, passwd_file, display);
                env_check_password_file(passwd_file, password);

                g_snprintf(text, 255, "%d", g_cfg->sess.max_idle_time);
                g_setenv("XRDP_SESMAN_MAX_IDLE_TIME", text, 1);
                g_snprintf(text, 255, "%d", g_cfg->sess.max_disc_time);
                g_setenv("XRDP_SESMAN_MAX_DISC_TIME", text, 1);
                g_snprintf(text, 255, "%d", g_cfg->sess.kill_disconnected);
                g_setenv("XRDP_SESMAN_KILL_DISCONNECTED", text, 1);

				if (type == SESMAN_SESSION_TYPE_XORG)
				{
                    xserver_params = list_create();
                    xserver_params->auto_free = 1;
                    
                    /* these are the must have parameters */
                    list_add_item(xserver_params, (long) g_strdup("/usr/bin/Xorg"));
                    list_add_item(xserver_params, (long) g_strdup(screen));

                    /* additional parameters from sesman.ini file */
                    list_append_list_strdup(g_cfg->xorg_params, xserver_params, 0);

                    /* make sure it ends with a zero */
                    list_add_item(xserver_params, 0);

                    pp1 = (char **) xserver_params->items;

                    log_message(LOG_LEVEL_INFO, "%s", dumpItemsToString(xserver_params, execvpparams, 2048));

                    /* some args are passed via env vars */
                    g_sprintf(geometry, "%d", width);
                    g_setenv("XRDP_START_WIDTH", geometry, 1);
                    
                    g_sprintf(geometry, "%d", height);
                    g_setenv("XRDP_START_HEIGHT", geometry, 1);
    
					/* fire up Xorg */
                    g_execvp("/usr/bin/Xorg", pp1);
				}
                else if (type == SESMAN_SESSION_TYPE_XVNC)
                {
                    xserver_params = list_create();
                    xserver_params->auto_free = 1;
                    
                    /* these are the must have parameters */
                    list_add_item(xserver_params, (long)g_strdup("Xvnc"));
                    list_add_item(xserver_params, (long)g_strdup(screen));
                    list_add_item(xserver_params, (long)g_strdup("-geometry"));
                    list_add_item(xserver_params, (long)g_strdup(geometry));
                    list_add_item(xserver_params, (long)g_strdup("-depth"));
                    list_add_item(xserver_params, (long)g_strdup(depth));
                    list_add_item(xserver_params, (long)g_strdup("-rfbauth"));
                    list_add_item(xserver_params, (long)g_strdup(passwd_file));

                    /* additional parameters from sesman.ini file */
                    //config_read_xserver_params(SESMAN_SESSION_TYPE_XVNC,
                    //                           xserver_params);
                    list_append_list_strdup(g_cfg->vnc_params, xserver_params, 0);

                    /* make sure it ends with a zero */
                    list_add_item(xserver_params, 0);
                    pp1 = (char **)xserver_params->items;
                    log_message(LOG_LEVEL_INFO, "%s", dumpItemsToString(xserver_params, execvpparams, 2048));
                    g_execvp("Xvnc", pp1);
                }
                else if (type == SESMAN_SESSION_TYPE_XRDP)
                {
                    xserver_params = list_create();
                    xserver_params->auto_free = 1;
                    
                    /* these are the must have parameters */
                    list_add_item(xserver_params, (long)g_strdup("X11rdp"));
                    list_add_item(xserver_params, (long)g_strdup(screen));
                    list_add_item(xserver_params, (long)g_strdup("-geometry"));
                    list_add_item(xserver_params, (long)g_strdup(geometry));
                    list_add_item(xserver_params, (long)g_strdup("-depth"));
                    list_add_item(xserver_params, (long)g_strdup(depth));

                    /* additional parameters from sesman.ini file */
                    //config_read_xserver_params(SESMAN_SESSION_TYPE_XRDP,
                    //                           xserver_params);
                    list_append_list_strdup(g_cfg->rdp_params, xserver_params, 0);

                    /* make sure it ends with a zero */
                    list_add_item(xserver_params, 0);
                    pp1 = (char **)xserver_params->items;
                    log_message(LOG_LEVEL_INFO, "%s", dumpItemsToString(xserver_params, execvpparams, 2048));
                    g_execvp("X11rdp", pp1);
                }
                else
                {
                    log_message(LOG_LEVEL_ALWAYS, "bad session type - "
                                "user %s - pid %d", username, g_getpid());
                    g_exit(1);
                }

                /* should not get here */
                log_message(LOG_LEVEL_ALWAYS, "error starting X server "
                            "- user %s - pid %d", username, g_getpid());

                /* logging parameters */
                log_message(LOG_LEVEL_DEBUG, "errno: %d, description: "
                            "%s", errno, g_get_strerror());
                log_message(LOG_LEVEL_DEBUG, "execve parameter list size: "
                            "%d", (xserver_params)->count);

                for (i = 0; i < (xserver_params->count); i++)
                {
                    log_message(LOG_LEVEL_DEBUG, "        argv[%d] = %s",
                                i, (char *)list_get_item(xserver_params, i));
                }

                list_delete(xserver_params);
                g_exit(1);
            }
            else /* parent (child sesman)*/
            {
                wait_for_xserver(display);
                g_snprintf(text, 255, "%d", display);
                g_setenv("XRDP_SESSVC_DISPLAY", text, 1);
                g_snprintf(text, 255, ":%d.0", display);
                g_setenv("DISPLAY", text, 1);
                /* new style waiting for clients */
                session_start_sessvc(xpid, wmpid, data, username, display);
            }
        }
    }
    else /* parent sesman process */
    {
        temp->item->pid = pid;
        temp->item->display = display;
        temp->item->width = width;
        temp->item->height = height;
        temp->item->bpp = bpp;
        temp->item->data = data;
        g_strncpy(temp->item->client_ip, client_ip, 255);   /* store client ip data */
        g_strncpy(temp->item->name, username, 255);

        ltime = g_time1();
        localtime_r(&ltime, &stime);
        temp->item->connect_time.year = (tui16)(stime.tm_year + 1900);
        temp->item->connect_time.month = (tui8)stime.tm_mon;
        temp->item->connect_time.day = (tui8)stime.tm_mday;
        temp->item->connect_time.hour = (tui8)stime.tm_hour;
        temp->item->connect_time.minute = (tui8)stime.tm_min;
        zero_time(&(temp->item->disconnect_time));
        zero_time(&(temp->item->idle_time));

        temp->item->type = type;
        temp->item->status = SESMAN_SESSION_STATUS_ACTIVE;

        temp->next = g_sessions;
        g_sessions = temp;
        g_session_count++;
    }

    return display;
}

/******************************************************************************/
/* called with the main thread */
static int APP_CC
session_reconnect_fork(int display, char *username)
{
    int pid;
    char text[256];

    pid = g_fork();

    if (pid == -1)
    {
    }
    else if (pid == 0)
    {
        env_set_user(username, 0, display);
        g_snprintf(text, 255, "%s/%s", XRDP_CFG_PATH, "reconnectwm.sh");

        if (g_file_exist(text))
        {
            g_execlp3(text, g_cfg->default_wm, 0);
        }

        g_exit(0);
    }

    return display;
}

/******************************************************************************/
/* called by a worker thread, ask the main thread to call session_sync_start
   and wait till done */
int DEFAULT_CC
session_start(int width, int height, int bpp, char *username, char *password,
              long data, tui8 type, char *domain, char *program,
              char *directory, char *client_ip)
{
    int display;

    /* lock mutex */
    lock_sync_acquire();
    /* set shared vars */
    g_sync_cmd = 0;
    g_sync_width = width;
    g_sync_height = height;
    g_sync_bpp = bpp;
    g_sync_username = username;
    g_sync_password = password;
    g_sync_domain = domain;
    g_sync_program = program;
    g_sync_directory = directory;
    g_sync_client_ip = client_ip;
    g_sync_data = data;
    g_sync_type = type;
    /* set event for main thread to see */
    g_set_wait_obj(g_sync_event);
    /* wait for main thread to get done */
    lock_sync_sem_acquire();
    /* read result(display) from shared var */
    display = g_sync_result;
    /* unlock mutex */
    lock_sync_release();
    return display;
}

/******************************************************************************/
/* called by a worker thread, ask the main thread to call session_sync_start
   and wait till done */
int DEFAULT_CC
session_reconnect(int display, char *username)
{
    /* lock mutex */
    lock_sync_acquire();
    /* set shared vars */
    g_sync_cmd = 1;
    g_sync_width = display;
    g_sync_username = username;
    /* set event for main thread to see */
    g_set_wait_obj(g_sync_event);
    /* wait for main thread to get done */
    lock_sync_sem_acquire();
    /* unlock mutex */
    lock_sync_release();
    return 0;
}

/******************************************************************************/
/* called with the main thread */
int APP_CC
session_sync_start(void)
{
    if (g_sync_cmd == 0)
    {
        g_sync_result = session_start_fork(g_sync_width, g_sync_height, g_sync_bpp,
                                           g_sync_username, g_sync_password,
                                           g_sync_data, g_sync_type, g_sync_domain,
                                           g_sync_program, g_sync_directory,
                                           g_sync_client_ip);
    }
    else
    {
        /* g_sync_width is really display */
        g_sync_result = session_reconnect_fork(g_sync_width, g_sync_username);
    }

    lock_sync_sem_release();
    return 0;
}

/******************************************************************************/
int DEFAULT_CC
session_kill(int pid)
{
    struct session_chain *tmp;
    struct session_chain *prev;

    /*THREAD-FIX require chain lock */
    lock_chain_acquire();

    tmp = g_sessions;
    prev = 0;

    while (tmp != 0)
    {
        if (tmp->item == 0)
        {
            log_message(LOG_LEVEL_ERROR, "session descriptor for "
                        "pid %d is null!", pid);

            if (prev == 0)
            {
                /* prev does no exist, so it's the first element - so we set
                   g_sessions */
                g_sessions = tmp->next;
            }
            else
            {
                prev->next = tmp->next;
            }

            /*THREAD-FIX release chain lock */
            lock_chain_release();
            return SESMAN_SESSION_KILL_NULLITEM;
        }

        if (tmp->item->pid == pid)
        {
            /* deleting the session */
            log_message(LOG_LEVEL_INFO, "++ terminated session:  username %s, display :%d.0, session_pid %d, ip %s", tmp->item->name, tmp->item->display, tmp->item->pid, tmp->item->client_ip);
            g_free(tmp->item);

            if (prev == 0)
            {
                /* prev does no exist, so it's the first element - so we set
                   g_sessions */
                g_sessions = tmp->next;
            }
            else
            {
                prev->next = tmp->next;
            }

            g_free(tmp);
            g_session_count--;
            /*THREAD-FIX release chain lock */
            lock_chain_release();
            return SESMAN_SESSION_KILL_OK;
        }

        /* go on */
        prev = tmp;
        tmp = tmp->next;
    }

    /*THREAD-FIX release chain lock */
    lock_chain_release();
    return SESMAN_SESSION_KILL_NOTFOUND;
}

/******************************************************************************/
void DEFAULT_CC
session_sigkill_all()
{
    struct session_chain *tmp;

    /*THREAD-FIX require chain lock */
    lock_chain_acquire();

    tmp = g_sessions;

    while (tmp != 0)
    {
        if (tmp->item == 0)
        {
            log_message(LOG_LEVEL_ERROR, "found null session "
                        "descriptor!");
        }
        else
        {
            g_sigterm(tmp->item->pid);
        }

        /* go on */
        tmp = tmp->next;
    }

    /*THREAD-FIX release chain lock */
    lock_chain_release();
}

/******************************************************************************/
struct session_item *DEFAULT_CC
session_get_bypid(int pid)
{
    struct session_chain *tmp;
    struct session_item *dummy;

    dummy = g_malloc(sizeof(struct session_item), 1);

    if (0 == dummy)
    {
        log_message(LOG_LEVEL_ERROR, "internal error", pid);
        return 0;
    }

    /*THREAD-FIX require chain lock */
    lock_chain_acquire();

    tmp = g_sessions;

    while (tmp != 0)
    {
        if (tmp->item == 0)
        {
            log_message(LOG_LEVEL_ERROR, "session descriptor for "
                        "pid %d is null!", pid);
            /*THREAD-FIX release chain lock */
            lock_chain_release();
            return 0;
        }

        if (tmp->item->pid == pid)
        {
            /*THREAD-FIX release chain lock */
            g_memcpy(dummy, tmp->item, sizeof(struct session_item));
            lock_chain_release();
            /*return tmp->item;*/
            return dummy;
        }

        /* go on */
        tmp = tmp->next;
    }

    /*THREAD-FIX release chain lock */
    lock_chain_release();
    return 0;
}

/******************************************************************************/
struct SCP_DISCONNECTED_SESSION *
session_get_byuser(char *user, int *cnt, unsigned char flags)
{
    struct session_chain *tmp;
    struct SCP_DISCONNECTED_SESSION *sess;
    int count;
    int index;

    count = 0;

    /*THREAD-FIX require chain lock */
    lock_chain_acquire();

    tmp = g_sessions;

    while (tmp != 0)
    {
        LOG_DBG("user: %s", user);

        if ((NULL == user) || (!g_strncasecmp(user, tmp->item->name, 256)))
        {
            LOG_DBG("session_get_byuser: status=%d, flags=%d, "
                    "result=%d", (tmp->item->status), flags,
                    ((tmp->item->status) & flags));

            if ((tmp->item->status) & flags)
            {
                count++;
            }
        }

        /* go on */
        tmp = tmp->next;
    }

    if (count == 0)
    {
        (*cnt) = 0;
        /*THREAD-FIX release chain lock */
        lock_chain_release();
        return 0;
    }

    /* malloc() an array of disconnected sessions */
    sess = g_malloc(count *sizeof(struct SCP_DISCONNECTED_SESSION), 1);

    if (sess == 0)
    {
        (*cnt) = 0;
        /*THREAD-FIX release chain lock */
        lock_chain_release();
        return 0;
    }

    tmp = g_sessions;
    index = 0;

    while (tmp != 0)
    {
#warning FIXME: we should get only disconnected sessions!
        if ((NULL == user) || (!g_strncasecmp(user, tmp->item->name, 256)))
        {
            if ((tmp->item->status) & flags)
            {
                (sess[index]).SID = tmp->item->pid;
                (sess[index]).type = tmp->item->type;
                (sess[index]).height = tmp->item->height;
                (sess[index]).width = tmp->item->width;
                (sess[index]).bpp = tmp->item->bpp;
#warning FIXME: setting idle times and such
                /*(sess[index]).connect_time.year = tmp->item->connect_time.year;
                (sess[index]).connect_time.month = tmp->item->connect_time.month;
                (sess[index]).connect_time.day = tmp->item->connect_time.day;
                (sess[index]).connect_time.hour = tmp->item->connect_time.hour;
                (sess[index]).connect_time.minute = tmp->item->connect_time.minute;
                (sess[index]).disconnect_time.year = tmp->item->disconnect_time.year;
                (sess[index]).disconnect_time.month = tmp->item->disconnect_time.month;
                (sess[index]).disconnect_time.day = tmp->item->disconnect_time.day;
                (sess[index]).disconnect_time.hour = tmp->item->disconnect_time.hour;
                (sess[index]).disconnect_time.minute = tmp->item->disconnect_time.minute;
                (sess[index]).idle_time.year = tmp->item->idle_time.year;
                (sess[index]).idle_time.month = tmp->item->idle_time.month;
                (sess[index]).idle_time.day = tmp->item->idle_time.day;
                (sess[index]).idle_time.hour = tmp->item->idle_time.hour;
                (sess[index]).idle_time.minute = tmp->item->idle_time.minute;*/
                (sess[index]).conn_year = tmp->item->connect_time.year;
                (sess[index]).conn_month = tmp->item->connect_time.month;
                (sess[index]).conn_day = tmp->item->connect_time.day;
                (sess[index]).conn_hour = tmp->item->connect_time.hour;
                (sess[index]).conn_minute = tmp->item->connect_time.minute;
                (sess[index]).idle_days = tmp->item->idle_time.day;
                (sess[index]).idle_hours = tmp->item->idle_time.hour;
                (sess[index]).idle_minutes = tmp->item->idle_time.minute;

                index++;
            }
        }

        /* go on */
        tmp = tmp->next;
    }

    /*THREAD-FIX release chain lock */
    lock_chain_release();
    (*cnt) = count;
    return sess;
}