/* --- BEGIN COPYRIGHT BLOCK ---
 * This Program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; version 2 of the License.
 * 
 * This Program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * this Program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place, Suite 330, Boston, MA 02111-1307 USA.
 * 
 * In addition, as a special exception, Red Hat, Inc. gives You the additional
 * right to link the code of this Program with code not covered under the GNU
 * General Public License ("Non-GPL Code") and to distribute linked combinations
 * including the two, subject to the limitations in this paragraph. Non-GPL Code
 * permitted under this exception must only link to the code of this Program
 * through those well defined interfaces identified in the file named EXCEPTION
 * found in the source code files (the "Approved Interfaces"). The files of
 * Non-GPL Code may instantiate templates or use macros or inline functions from
 * the Approved Interfaces without causing the resulting work to be covered by
 * the GNU General Public License. Only Red Hat, Inc. may make changes or
 * additions to the list of Approved Interfaces. You must obey the GNU General
 * Public License in all respects for all of the Program code and other code used
 * in conjunction with the Program except the Non-GPL Code covered by this
 * exception. If you modify this file, you may extend this exception to your
 * version of the file, but you are not obligated to do so. If you do not wish to
 * provide this exception without modification, you must delete this exception
 * statement from your version and license this file solely under the GPL without
 * exception. 
 * 
 * 
 * Copyright (C) 2005 Red Hat, Inc.
 * All rights reserved.
 * --- END COPYRIGHT BLOCK --- */

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


#include <signal.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <signal.h>
#include <sys/stat.h>
#include "ldap-agent.h"
#include "ldap.h"
#include "ldif.h"

static char *agentx_master = NULL;
static char *agent_logdir = NULL;
static char *pidfile = NULL;
server_instance *server_head = NULL;

static int keep_running;

RETSIGTYPE
stop_server(int signum) {
    if (signum == SIGUSR1) {
        snmp_log(LOG_WARNING, "Detected attempt to start ldap-agent again.\n");
    } else {
        snmp_log(LOG_WARNING, "Received stop signal.  Stopping ldap-agent...\n");
        keep_running = 0;
    }
}

int
main (int argc, char *argv[]) {
    char                *config_file = NULL;
    netsnmp_log_handler *log_hdl = NULL;
    int                 c, log_level = LOG_WARNING;
    struct stat         logdir_s;
    pid_t               child_pid;
    FILE                *pid_fp;

    /* Load options */
    while ((--argc > 0) && ((*++argv)[0] == '-')) {
        while ((c = *++argv[0])) {
            switch (c) {
            case 'D':
                log_level = LOG_DEBUG;
                break;
            default:
                printf("ldap-agent: illegal option %c\n", c);
                exit_usage();
            }
        }
    }

    if (argc != 1)
        exit_usage();

    /* load config file */
    if ((config_file = strdup(*argv)) == NULL) {
        printf("ldap-agent: Memory error loading config file\n");
        exit(1);
    }

    load_config(config_file);

    /* check if we're already running as another process */
    if ((pid_fp = fopen(pidfile, "r")) != NULL) {
        fscanf(pid_fp, "%d", &child_pid);
        fclose(pid_fp);
        if (kill(child_pid, SIGUSR1) == 0) {
            printf("ldap-agent: Already running as pid %d!\n", child_pid);
            exit(1);
        } else {
            /* old pidfile exists, but the process doesn't. Cleanup pidfile */
            remove(pidfile);
        }
    }

    /* start logging */
    netsnmp_ds_set_boolean(NETSNMP_DS_LIBRARY_ID,
                           NETSNMP_DS_LIB_LOG_TIMESTAMP, 1);

    if ((log_hdl = netsnmp_register_loghandler(NETSNMP_LOGHANDLER_FILE,
                                               log_level)) != NULL) {
        if (agent_logdir != NULL) {
            /* Verify agent-logdir setting */
            if (stat(agent_logdir, &logdir_s) < 0) {
                printf("ldap-agent: Error reading logdir: %s\n", agent_logdir);
                exit(1);
            } else {
                /* Is it a directory? */
                if (S_ISDIR(logdir_s.st_mode)) {
                    /* Can we write to it? */
                    if (access(agent_logdir, W_OK) < 0) {
                        printf("ldap-agent: Unable to write to logdir: %s\n",
                                agent_logdir);
                        exit(1);
                    }
                } else {
                    printf("ldap-agent: agent-logdir setting must point to a directory.\n");
                    exit(1);
                }
            }

            /* agent-logdir setting looks ok */
            if ((log_hdl->token = malloc(strlen(agent_logdir) +
                                   strlen(LDAP_AGENT_LOGFILE) + 2)) != NULL) {
                strncpy((char *) log_hdl->token, agent_logdir, strlen(agent_logdir) + 1);
                /* add a trailing slash if needed */
                if (*(agent_logdir + strlen(agent_logdir)) != '/')
                    strcat((char *) log_hdl->token, "/");
                strcat((char *) log_hdl->token, LDAP_AGENT_LOGFILE);
                ((char*)log_hdl->token)[(strlen(agent_logdir) + strlen(LDAP_AGENT_LOGFILE) + 1)] = (char)0;
            }
        } else {
            /* agent-logdir not set */
            printf("ldap-agent: Error determining log directory.\n");
            exit(1);
        } 

        snmp_enable_filelog((char*)log_hdl->token, 1);
    } else {
        printf("Error starting logging.");
        exit(1);
    }

    snmp_log(LOG_WARNING, "Starting ldap-agent...\n");

    /* setup agentx master */
    netsnmp_ds_set_boolean(NETSNMP_DS_APPLICATION_ID,
                           NETSNMP_DS_AGENT_ROLE, 1);
    if (agentx_master)
        netsnmp_ds_set_string(NETSNMP_DS_APPLICATION_ID,
                              NETSNMP_DS_AGENT_X_SOCKET, agentx_master);

    /* run as a daemon */
    if (netsnmp_daemonize(0, 0)) {
        int i;

        /* sleep to allow pidfile to be created by child */
        for (i=0; i < 3; i++) {
            sleep(5);
            if((pid_fp = fopen(pidfile,"r")) != NULL) {
                break;
            }
        }

        if(!pid_fp) {
            printf("ldap-agent: Not started after 15 seconds!  Check log file for details.\n");
            exit(1);
        }

        fscanf(pid_fp, "%d", &child_pid);
        fclose(pid_fp);
        printf("ldap-agent: Started as pid %d\n", child_pid);
        exit(0);
    }

    /* initialize the agent */
    init_agent("ldap-agent");
    init_ldap_agent();  
    init_snmp("ldap-agent");

    /* listen for signals */
    keep_running = 1;
    signal(SIGUSR1, stop_server);
    signal(SIGTERM, stop_server);
    signal(SIGINT, stop_server);

    /* create pidfile */
    child_pid = getpid();
    if ((pid_fp = fopen(pidfile, "w")) == NULL) {
        snmp_log(LOG_ERR, "Error creating pid file: %s\n", pidfile);
        exit(1);
    } else {
        if (fprintf(pid_fp, "%d", child_pid) < 0) {
            snmp_log(LOG_ERR, "Error writing pid file: %s\n", pidfile);
            exit(1);
        }
        fclose(pid_fp);
    }

    /* we're up and running! */
    snmp_log(LOG_WARNING, "Started ldap-agent as pid %d\n", child_pid);

    /* loop here until asked to stop */
    while(keep_running) {
      agent_check_and_process(1);
    }

    /* say goodbye */
    snmp_shutdown("ldap-agent");
    snmp_log(LOG_WARNING, "ldap-agent stopped.\n");

    /* remove pidfile */ 
    remove(pidfile);

    return 0;
}

/************************************************************************
 * load_config
 *
 * Loads subagent config file and reads directory server config files.
 */
void
load_config(char *conf_path)
{
    server_instance *serv_p = NULL;
    FILE *conf_file = NULL;
#if defined(USE_OPENLDAP)
    LDIFFP *dse_fp = NULL;
    int buflen;
#else
    FILE *dse_fp = NULL;
#endif
    char line[MAXLINE];
    char *p = NULL;
    int error = 0;

    /* Make sure we are getting an absolute path */
    if (*conf_path != '/') {
        printf("ldap-agent: Error opening config file: %s\n", conf_path);
        printf("ldap-agent: You must specify the absolute path to your config file\n");
        error = 1;
        goto close_and_exit;
    }

    /* Open config file */
    if ((conf_file = fopen(conf_path, "r")) == NULL) {
        printf("ldap-agent: Error opening config file: %s\n", conf_path);
        error = 1;
        goto close_and_exit;
    } 

    /* set pidfile path */
    if ((pidfile = malloc(strlen(LOCALSTATEDIR) + strlen("/run/") +
        strlen(LDAP_AGENT_PIDFILE) + 1)) != NULL) {
        strncpy(pidfile, LOCALSTATEDIR, strlen(LOCALSTATEDIR));
        /* The above will likely not be NULL terminated, but we need to
         * be sure that we're properly NULL terminated for the below
         * strcat() to work properly. */
        pidfile[strlen(LOCALSTATEDIR)] = (char)0;
        strcat(pidfile, "/run/");
        strcat(pidfile, LDAP_AGENT_PIDFILE);
    } else {
        printf("ldap-agent: malloc error processing config file\n");
        error = 1;
        goto close_and_exit;
    }

    /* set default logdir to location of config file */
    for (p = (conf_path + strlen(conf_path) - 1); p >= conf_path; p--) {
        if (*p == '/') {
            if ((agent_logdir = malloc((p - conf_path) + 1)) != NULL) {
                strncpy(agent_logdir, conf_path, (p - conf_path));
                agent_logdir[(p - conf_path)] = (char)0;
                break;
            } else {
                printf("ldap-agent: malloc error processing config file\n");
                error = 1;
                goto close_and_exit;
            }
        }
    }

    while (fgets(line, MAXLINE, conf_file) != NULL) {
        /* Ignore comment lines in config file */
        if (line[0] == '#')
            continue;

        if ((p = strstr(line, "agentx-master")) != NULL) {
            /* load agentx-master setting */
            p = p + 13;
            if ((p = strtok(p, " \t\n")) != NULL) {
                if ((agentx_master = (char *) malloc(strlen(p) + 1)) != NULL)
                    strcpy(agentx_master, p);
            }
        } else if ((p = strstr(line, "agent-logdir")) != NULL) {
            /* free the default logdir setting */
            if (agent_logdir != NULL) {
                free(agent_logdir);
            }

            /* load agent-logdir setting */
            p = p + 12;
            if ((p = strtok(p, " \t\n")) != NULL) {
                if ((agent_logdir = (char *) malloc(strlen(p) + 1)) != NULL)
                    strcpy(agent_logdir, p);
            }
        } else if ((p = strstr(line, "server")) != NULL) {
            int got_port = 0;
            int got_rundir = 0;
            int lineno = 0;
            char *entry = NULL;
            char *instancename = NULL;

            /* Allocate a server_instance */
            if ((serv_p = malloc(sizeof(server_instance))) == NULL) {
                printf("ldap-agent: malloc error processing config file\n");
                error = 1;
                goto close_and_exit;
            }

            /* load server setting */
            p = p + 6;
            if ((p = strtok(p, " \t\n")) != NULL) {
                /* first token is the instance name */
                instancename = strdup(p);
                serv_p->dse_ldif = malloc(strlen(p) + strlen(SYSCONFDIR) +
                                           strlen(PACKAGE_NAME) + 12);
                if (serv_p->dse_ldif != NULL) {
                    snprintf(serv_p->dse_ldif, strlen(p) + strlen(SYSCONFDIR) +
                         strlen(PACKAGE_NAME) + 12, "%s/%s/%s/dse.ldif", 
                         SYSCONFDIR, PACKAGE_NAME, p);
                    serv_p->dse_ldif[(strlen(p) + strlen(SYSCONFDIR) +
                                      strlen(PACKAGE_NAME) + 11)] = (char)0;
                } else {
                    printf("ldap-agent: malloc error processing config file\n");
                    error = 1;
                    free(instancename);
                    instancename = NULL;
                    goto close_and_exit;
                }

                /* set the semaphore name */
                /* "/" + ".stats" + \0 = 8 */
                serv_p->stats_sem_name = malloc(strlen(p) + 8);
                if (serv_p->stats_sem_name != NULL) {
                    snprintf(serv_p->stats_sem_name, strlen(p) + 8, "/%s.stats", p);
                } else {
                    printf("ldap-agent: malloc error processing config file\n");
                    error = 1;
                    free(instancename);
                    instancename = NULL;
                    goto close_and_exit;
                }
            } else {
                printf("ldap-agent: missing instance name\n");
                error = 1;
                goto close_and_exit;
            }
 
            /* Open dse.ldif */
#if defined(USE_OPENLDAP)
            dse_fp = ldif_open(serv_p->dse_ldif, "r");
#else
            dse_fp = fopen(serv_p->dse_ldif, "r");
#endif
            if (dse_fp == NULL) {
                printf("ldap-agent: Error opening server config file: %s\n",
                        serv_p->dse_ldif);
                error = 1;
                free(instancename);
                instancename = NULL;
                goto close_and_exit;
            }

            /* ldif_get_entry will realloc the entry if it's not null,
             * so we can just free it when we're done fetching entries
             * from the dse.ldif.  Unfortunately, ldif_getline moves
             * the pointer that is passed to it, so we need to save a
             * pointer to the beginning of the entry so we can free it
             * later. */
#if defined(USE_OPENLDAP)
            while (ldif_read_record(dse_fp, &lineno, &entry, &buflen))
#else
            while ((entry = ldif_get_entry(dse_fp, &lineno)) != NULL)
#endif
            {
                char *entryp = entry;
                char *attr = NULL;
                char *val = NULL;
#if defined(USE_OPENLDAP)
                ber_len_t vlen;
#else
                int vlen;
#endif
                /* Check if this is the cn=config entry */
                if (ldif_parse_line(ldif_getline(&entryp), &attr, &val, &vlen)) {
                    printf("ldap-agent: error parsing ldif line from [%s]\n", serv_p->dse_ldif);
                }

                if ((strcmp(attr, "dn") == 0) &&
                    (strcmp(val, "cn=config") == 0)) {
                    char *dse_line = NULL;
                    /* Look for port and rundir attributes */
                    while ((dse_line = ldif_getline(&entryp)) != NULL) {
                        ldif_parse_line(dse_line, &attr, &val, &vlen);
                        if (strcmp(attr, "nsslapd-port") == 0) {
                            serv_p->port = atol(val);
                            got_port = 1;
                        } else if (strcmp(attr, "nsslapd-rundir") == 0) {
                            /* 8 =  "/" + ".stats" + \0 */
                            serv_p->stats_file = malloc(vlen + strlen(instancename) + 8);
                            if (serv_p->stats_file != NULL) {
                                snprintf(serv_p->stats_file, vlen + strlen(instancename) + 8,
                                         "%s/%s.stats", val, instancename);
                                serv_p->stats_file[(vlen + strlen(instancename) + 7)] = (char)0;
                            } else {
                                printf("ldap-agent: malloc error processing config file\n");
                                free(entry);
                                error = 1;
                                free(instancename);
                                instancename = NULL;
                                goto close_and_exit;
                            }
                            got_rundir = 1;
                        }

                        /* Stop processing this entry if we found the
                         *  port and rundir settings */
                        if (got_port && got_rundir) {
                            break;
                        }
                    }
                    /* The port and rundir settings must be in the
                     * cn=config entry, so we can stop reading through
                     * the dse.ldif now. */
                    break;
                }
            }

            free(instancename);
            instancename = NULL;
            /* We're done reading entries from dse_ldif now, so
             * we can free entry */
            free(entry);

            /* Make sure we were able to read the port and
             * location of the stats file. */
            if (!got_port) {
                printf("ldap-agent: Error reading nsslapd-port from "
                       "server config file: %s\n", serv_p->dse_ldif);
                error = 1;
                goto close_and_exit;
            } else if (!got_rundir) {
                printf("ldap-agent: Error reading nsslapd-rundir from "
                       "server config file: %s\n", serv_p->dse_ldif);
                error = 1;
                goto close_and_exit;
            }

            /* Insert server instance into linked list */
            serv_p->next = server_head;
            server_head = serv_p;
        }
    }

    /* check for at least one directory server instance */
    if (server_head == NULL) {
        printf("ldap-agent: No server instances defined in config file\n");
        error = 1;
        goto close_and_exit;
    }

close_and_exit:
    if (conf_file)
        fclose(conf_file);
    if (dse_fp) {
#if defined(USE_OPENLDAP)
        ldif_close(dse_fp);
#else
        fclose(dse_fp);
#endif
    }
    if (error)
        exit(error);
}

/************************************************************************
 * exit_usage
 *
 * Prints usage message and exits program.
 */
void
exit_usage()
{
    printf("Usage: ldap-agent [-D] configfile\n");
    printf("       -D    Enable debug logging\n");
    exit(1);
}