cdr_pgsql.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2003 - 2012
 *
 * Matthew D. Hardeman <mhardemn@papersoft.com>
 * Adapted from the MySQL CDR logger originally by James Sharp
 *
 * Modified September 2003
 * Matthew D. Hardeman <mhardemn@papersoft.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*!
 * \file
 * \brief PostgreSQL CDR logger
 *
 * \author Matthew D. Hardeman <mhardemn@papersoft.com>
 * \extref PostgreSQL http://www.postgresql.org/
 *
 * See also
 * \arg \ref Config_cdr
 * \extref PostgreSQL http://www.postgresql.org/
 * \ingroup cdr_drivers
 */

/*** MODULEINFO
   <depend>pgsql</depend>
   <support_level>extended</support_level>
 ***/

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 354275 $")

#include <libpq-fe.h>

#include "asterisk/config.h"
#include "asterisk/channel.h"
#include "asterisk/cdr.h"
#include "asterisk/cli.h"
#include "asterisk/module.h"

#define DATE_FORMAT "'%Y-%m-%d %T'"

static const char name[] = "pgsql";
static const char config[] = "cdr_pgsql.conf";
static char *pghostname = NULL, *pgdbname = NULL, *pgdbuser = NULL, *pgpassword = NULL, *pgdbport = NULL, *table = NULL, *encoding = NULL, *tz = NULL;
static int connected = 0;
static int maxsize = 512, maxsize2 = 512;
static time_t connect_time = 0;
static int totalrecords = 0;
static int records;

static char *handle_cdr_pgsql_status(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a);
static struct ast_cli_entry cdr_pgsql_status_cli[] = {
        AST_CLI_DEFINE(handle_cdr_pgsql_status, "Show connection status of the PostgreSQL CDR driver (cdr_pgsql)"),
};

AST_MUTEX_DEFINE_STATIC(pgsql_lock);

static PGconn  *conn = NULL;

struct columns {
   char *name;
   char *type;
   int len;
   unsigned int notnull:1;
   unsigned int hasdefault:1;
   AST_RWLIST_ENTRY(columns) list;
};

static AST_RWLIST_HEAD_STATIC(psql_columns, columns);

#define LENGTHEN_BUF1(size)                                               \
         do {                                                          \
            /* Lengthen buffer, if necessary */                       \
            if (ast_str_strlen(sql) + size + 1 > ast_str_size(sql)) { \
               if (ast_str_make_space(&sql, ((ast_str_size(sql) + size + 3) / 512 + 1) * 512) != 0) { \
                  ast_log(LOG_ERROR, "Unable to allocate sufficient memory.  Insert CDR failed.\n"); \
                  ast_free(sql);                                    \
                  ast_free(sql2);                                   \
                  AST_RWLIST_UNLOCK(&psql_columns);                 \
                  ast_mutex_unlock(&pgsql_lock);                    \
                  return -1;                                        \
               }                                                     \
            }                                                         \
         } while (0)

#define LENGTHEN_BUF2(size)                               \
         do {                                          \
            if (ast_str_strlen(sql2) + size + 1 > ast_str_size(sql2)) {  \
               if (ast_str_make_space(&sql2, ((ast_str_size(sql2) + size + 3) / 512 + 1) * 512) != 0) {  \
                  ast_log(LOG_ERROR, "Unable to allocate sufficient memory.  Insert CDR failed.\n");  \
                  ast_free(sql);                    \
                  ast_free(sql2);                   \
                  AST_RWLIST_UNLOCK(&psql_columns); \
                  ast_mutex_unlock(&pgsql_lock);    \
                  return -1;                        \
               }                                     \
            }                                         \
         } while (0)

/*! \brief Handle the CLI command cdr show pgsql status */
static char *handle_cdr_pgsql_status(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   switch (cmd) {
   case CLI_INIT:
      e->command = "cdr show pgsql status";
      e->usage =
         "Usage: cdr show pgsql status\n"
         "       Shows current connection status for cdr_pgsql\n";
      return NULL;
   case CLI_GENERATE:
      return NULL;
   }

   if (a->argc != 3)
      return CLI_SHOWUSAGE;

   if (connected) {
      char status[256], status2[100] = "";
      int ctime = time(NULL) - connect_time;

      if (pgdbport) {
         snprintf(status, 255, "Connected to %s@%s, port %s", pgdbname, pghostname, pgdbport);
      } else {
         snprintf(status, 255, "Connected to %s@%s", pgdbname, pghostname);
      }

      if (pgdbuser && *pgdbuser) {
         snprintf(status2, 99, " with username %s", pgdbuser);
      }
      if (table && *table) {
         snprintf(status2, 99, " using table %s", table);
      }
      if (ctime > 31536000) {
         ast_cli(a->fd, "%s%s for %d years, %d days, %d hours, %d minutes, %d seconds.\n", status, status2, ctime / 31536000, (ctime % 31536000) / 86400, (ctime % 86400) / 3600, (ctime % 3600) / 60, ctime % 60);
      } else if (ctime > 86400) {
         ast_cli(a->fd, "%s%s for %d days, %d hours, %d minutes, %d seconds.\n", status, status2, ctime / 86400, (ctime % 86400) / 3600, (ctime % 3600) / 60, ctime % 60);
      } else if (ctime > 3600) {
         ast_cli(a->fd, "%s%s for %d hours, %d minutes, %d seconds.\n", status, status2, ctime / 3600, (ctime % 3600) / 60, ctime % 60);
      } else if (ctime > 60) {
         ast_cli(a->fd, "%s%s for %d minutes, %d seconds.\n", status, status2, ctime / 60, ctime % 60);
      } else {
         ast_cli(a->fd, "%s%s for %d seconds.\n", status, status2, ctime);
      }
      if (records == totalrecords) {
         ast_cli(a->fd, "  Wrote %d records since last restart.\n", totalrecords);
      } else {
         ast_cli(a->fd, "  Wrote %d records since last restart and %d records since last reconnect.\n", totalrecords, records);
      }
   } else {
      ast_cli(a->fd, "Not currently connected to a PgSQL server.\n");
   }
   return CLI_SUCCESS;
}

static int pgsql_log(struct ast_cdr *cdr)
{
   struct ast_tm tm;
   char *pgerror;
   PGresult *result;

   ast_mutex_lock(&pgsql_lock);

   if ((!connected) && pghostname && pgdbuser && pgpassword && pgdbname) {
      conn = PQsetdbLogin(pghostname, pgdbport, NULL, NULL, pgdbname, pgdbuser, pgpassword);
      if (PQstatus(conn) != CONNECTION_BAD) {
         connected = 1;
         connect_time = time(NULL);
         records = 0;
         if (PQsetClientEncoding(conn, encoding)) {
#ifdef HAVE_PGSQL_pg_encoding_to_char
            ast_log(LOG_WARNING, "Failed to set encoding to '%s'.  Encoding set to default '%s'\n", encoding, pg_encoding_to_char(PQclientEncoding(conn)));
#else
            ast_log(LOG_WARNING, "Failed to set encoding to '%s'.  Encoding set to default.\n", encoding);
#endif
         }
      } else {
         pgerror = PQerrorMessage(conn);
         ast_log(LOG_ERROR, "Unable to connect to database server %s.  Calls will not be logged!\n", pghostname);
         ast_log(LOG_ERROR, "Reason: %s\n", pgerror);
         PQfinish(conn);
         conn = NULL;
      }
   }

   if (connected) {
      struct columns *cur;
      struct ast_str *sql = ast_str_create(maxsize), *sql2 = ast_str_create(maxsize2);
      char buf[257], escapebuf[513], *value;
      int first = 1;

      if (!sql || !sql2) {
         ast_free(sql);
         ast_free(sql2);
         return -1;
      }

      ast_str_set(&sql, 0, "INSERT INTO %s (", table);
      ast_str_set(&sql2, 0, " VALUES (");

      AST_RWLIST_RDLOCK(&psql_columns);
      AST_RWLIST_TRAVERSE(&psql_columns, cur, list) {
         /* For fields not set, simply skip them */
         ast_cdr_getvar(cdr, cur->name, &value, buf, sizeof(buf), 0, 0);
         if (strcmp(cur->name, "calldate") == 0 && !value) {
            ast_cdr_getvar(cdr, "start", &value, buf, sizeof(buf), 0, 0);
         }
         if (!value) {
            if (cur->notnull && !cur->hasdefault) {
               /* Field is NOT NULL (but no default), must include it anyway */
               LENGTHEN_BUF1(strlen(cur->name) + 2);
               ast_str_append(&sql, 0, "%s\"%s\"", first ? "" : ",", cur->name);
               LENGTHEN_BUF2(3);
               ast_str_append(&sql2, 0, "%s''", first ? "" : ",");
               first = 0;
            }
            continue;
         }

         LENGTHEN_BUF1(strlen(cur->name) + 2);
         ast_str_append(&sql, 0, "%s\"%s\"", first ? "" : ",", cur->name);

         if (strcmp(cur->name, "start") == 0 || strcmp(cur->name, "calldate") == 0) {
            if (strncmp(cur->type, "int", 3) == 0) {
               LENGTHEN_BUF2(13);
               ast_str_append(&sql2, 0, "%s%ld", first ? "" : ",", (long) cdr->start.tv_sec);
            } else if (strncmp(cur->type, "float", 5) == 0) {
               LENGTHEN_BUF2(31);
               ast_str_append(&sql2, 0, "%s%f", first ? "" : ",", (double)cdr->start.tv_sec + (double)cdr->start.tv_usec / 1000000.0);
            } else {
               /* char, hopefully */
               LENGTHEN_BUF2(31);
               ast_localtime(&cdr->start, &tm, tz);
               ast_strftime(buf, sizeof(buf), DATE_FORMAT, &tm);
               ast_str_append(&sql2, 0, "%s%s", first ? "" : ",", buf);
            }
         } else if (strcmp(cur->name, "answer") == 0) {
            if (strncmp(cur->type, "int", 3) == 0) {
               LENGTHEN_BUF2(13);
               ast_str_append(&sql2, 0, "%s%ld", first ? "" : ",", (long) cdr->answer.tv_sec);
            } else if (strncmp(cur->type, "float", 5) == 0) {
               LENGTHEN_BUF2(31);
               ast_str_append(&sql2, 0, "%s%f", first ? "" : ",", (double)cdr->answer.tv_sec + (double)cdr->answer.tv_usec / 1000000.0);
            } else {
               /* char, hopefully */
               LENGTHEN_BUF2(31);
               ast_localtime(&cdr->answer, &tm, tz);
               ast_strftime(buf, sizeof(buf), DATE_FORMAT, &tm);
               ast_str_append(&sql2, 0, "%s%s", first ? "" : ",", buf);
            }
         } else if (strcmp(cur->name, "end") == 0) {
            if (strncmp(cur->type, "int", 3) == 0) {
               LENGTHEN_BUF2(13);
               ast_str_append(&sql2, 0, "%s%ld", first ? "" : ",", (long) cdr->end.tv_sec);
            } else if (strncmp(cur->type, "float", 5) == 0) {
               LENGTHEN_BUF2(31);
               ast_str_append(&sql2, 0, "%s%f", first ? "" : ",", (double)cdr->end.tv_sec + (double)cdr->end.tv_usec / 1000000.0);
            } else {
               /* char, hopefully */
               LENGTHEN_BUF2(31);
               ast_localtime(&cdr->end, &tm, tz);
               ast_strftime(buf, sizeof(buf), DATE_FORMAT, &tm);
               ast_str_append(&sql2, 0, "%s%s", first ? "" : ",", buf);
            }
         } else if (strcmp(cur->name, "duration") == 0 || strcmp(cur->name, "billsec") == 0) {
            if (cur->type[0] == 'i') {
               /* Get integer, no need to escape anything */
               ast_cdr_getvar(cdr, cur->name, &value, buf, sizeof(buf), 0, 0);
               LENGTHEN_BUF2(13);
               ast_str_append(&sql2, 0, "%s%s", first ? "" : ",", value);
            } else if (strncmp(cur->type, "float", 5) == 0) {
               struct timeval *when = cur->name[0] == 'd' ? &cdr->start : ast_tvzero(cdr->answer) ? &cdr->end : &cdr->answer;
               LENGTHEN_BUF2(31);
               ast_str_append(&sql2, 0, "%s%f", first ? "" : ",", (double) (ast_tvdiff_us(cdr->end, *when) / 1000000.0));
            } else {
               /* Char field, probably */
               struct timeval *when = cur->name[0] == 'd' ? &cdr->start : ast_tvzero(cdr->answer) ? &cdr->end : &cdr->answer;
               LENGTHEN_BUF2(31);
               ast_str_append(&sql2, 0, "%s'%f'", first ? "" : ",", (double) (ast_tvdiff_us(cdr->end, *when) / 1000000.0));
            }
         } else if (strcmp(cur->name, "disposition") == 0 || strcmp(cur->name, "amaflags") == 0) {
            if (strncmp(cur->type, "int", 3) == 0) {
               /* Integer, no need to escape anything */
               ast_cdr_getvar(cdr, cur->name, &value, buf, sizeof(buf), 0, 1);
               LENGTHEN_BUF2(13);
               ast_str_append(&sql2, 0, "%s%s", first ? "" : ",", value);
            } else {
               /* Although this is a char field, there are no special characters in the values for these fields */
               ast_cdr_getvar(cdr, cur->name, &value, buf, sizeof(buf), 0, 0);
               LENGTHEN_BUF2(31);
               ast_str_append(&sql2, 0, "%s'%s'", first ? "" : ",", value);
            }
         } else {
            /* Arbitrary field, could be anything */
            ast_cdr_getvar(cdr, cur->name, &value, buf, sizeof(buf), 0, 0);
            if (strncmp(cur->type, "int", 3) == 0) {
               long long whatever;
               if (value && sscanf(value, "%30lld", &whatever) == 1) {
                  LENGTHEN_BUF2(26);
                  ast_str_append(&sql2, 0, "%s%lld", first ? "" : ",", whatever);
               } else {
                  LENGTHEN_BUF2(2);
                  ast_str_append(&sql2, 0, "%s0", first ? "" : ",");
               }
            } else if (strncmp(cur->type, "float", 5) == 0) {
               long double whatever;
               if (value && sscanf(value, "%30Lf", &whatever) == 1) {
                  LENGTHEN_BUF2(51);
                  ast_str_append(&sql2, 0, "%s%30Lf", first ? "" : ",", whatever);
               } else {
                  LENGTHEN_BUF2(2);
                  ast_str_append(&sql2, 0, "%s0", first ? "" : ",");
               }
            /* XXX Might want to handle dates, times, and other misc fields here XXX */
            } else {
               if (value)
                  PQescapeStringConn(conn, escapebuf, value, strlen(value), NULL);
               else
                  escapebuf[0] = '\0';
               LENGTHEN_BUF2(strlen(escapebuf) + 3);
               ast_str_append(&sql2, 0, "%s'%s'", first ? "" : ",", escapebuf);
            }
         }
         first = 0;
      }

      LENGTHEN_BUF1(ast_str_strlen(sql2) + 2);
      AST_RWLIST_UNLOCK(&psql_columns);
      ast_str_append(&sql, 0, ")%s)", ast_str_buffer(sql2));
      ast_verb(11, "[%s]\n", ast_str_buffer(sql));

      ast_debug(2, "inserting a CDR record.\n");

      /* Test to be sure we're still connected... */
      /* If we're connected, and connection is working, good. */
      /* Otherwise, attempt reconnect.  If it fails... sorry... */
      if (PQstatus(conn) == CONNECTION_OK) {
         connected = 1;
      } else {
         ast_log(LOG_ERROR, "Connection was lost... attempting to reconnect.\n");
         PQreset(conn);
         if (PQstatus(conn) == CONNECTION_OK) {
            ast_log(LOG_ERROR, "Connection reestablished.\n");
            connected = 1;
            connect_time = time(NULL);
            records = 0;
         } else {
            pgerror = PQerrorMessage(conn);
            ast_log(LOG_ERROR, "Unable to reconnect to database server %s. Calls will not be logged!\n", pghostname);
            ast_log(LOG_ERROR, "Reason: %s\n", pgerror);
            PQfinish(conn);
            conn = NULL;
            connected = 0;
            ast_mutex_unlock(&pgsql_lock);
            ast_free(sql);
            ast_free(sql2);
            return -1;
         }
      }
      result = PQexec(conn, ast_str_buffer(sql));
      if (PQresultStatus(result) != PGRES_COMMAND_OK) {
         pgerror = PQresultErrorMessage(result);
         ast_log(LOG_ERROR, "Failed to insert call detail record into database!\n");
         ast_log(LOG_ERROR, "Reason: %s\n", pgerror);
         ast_log(LOG_ERROR, "Connection may have been lost... attempting to reconnect.\n");
         PQreset(conn);
         if (PQstatus(conn) == CONNECTION_OK) {
            ast_log(LOG_ERROR, "Connection reestablished.\n");
            connected = 1;
            connect_time = time(NULL);
            records = 0;
            PQclear(result);
            result = PQexec(conn, ast_str_buffer(sql));
            if (PQresultStatus(result) != PGRES_COMMAND_OK) {
               pgerror = PQresultErrorMessage(result);
               ast_log(LOG_ERROR, "HARD ERROR!  Attempted reconnection failed.  DROPPING CALL RECORD!\n");
               ast_log(LOG_ERROR, "Reason: %s\n", pgerror);
            }  else {
               /* Second try worked out ok */
               totalrecords++;
               records++;
               ast_mutex_unlock(&pgsql_lock);
               PQclear(result);
               return 0;
            }
         }
         ast_mutex_unlock(&pgsql_lock);
         PQclear(result);
         ast_free(sql);
         ast_free(sql2);
         return -1;
      } else {
         totalrecords++;
         records++;
      }
      PQclear(result);
      ast_free(sql);
      ast_free(sql2);
   }
   ast_mutex_unlock(&pgsql_lock);
   return 0;
}

/* This function should be called without holding the pgsql_columns lock */
static void empty_columns(void)
{
   struct columns *current;
   AST_RWLIST_WRLOCK(&psql_columns);
   while ((current = AST_RWLIST_REMOVE_HEAD(&psql_columns, list))) {
      ast_free(current);
   }
   AST_RWLIST_UNLOCK(&psql_columns);

}

static int unload_module(void)
{
   ast_cdr_unregister(name);
   ast_cli_unregister_multiple(cdr_pgsql_status_cli, ARRAY_LEN(cdr_pgsql_status_cli));

   PQfinish(conn);

   ast_free(pghostname);
   ast_free(pgdbname);
   ast_free(pgdbuser);
   ast_free(pgpassword);
   ast_free(pgdbport);
   ast_free(table);
   ast_free(encoding);
   ast_free(tz);

   empty_columns();

   return 0;
}

static int config_module(int reload)
{
   struct ast_variable *var;
   char *pgerror;
   struct columns *cur;
   PGresult *result;
   const char *tmp;
   struct ast_config *cfg;
   struct ast_flags config_flags = { reload ? CONFIG_FLAG_FILEUNCHANGED : 0 };

   if ((cfg = ast_config_load(config, config_flags)) == NULL || cfg == CONFIG_STATUS_FILEINVALID) {
      ast_log(LOG_WARNING, "Unable to load config for PostgreSQL CDR's: %s\n", config);
      return -1;
   } else if (cfg == CONFIG_STATUS_FILEUNCHANGED) {
      return 0;
   }

   ast_mutex_lock(&pgsql_lock);

   if (!(var = ast_variable_browse(cfg, "global"))) {
      ast_config_destroy(cfg);
      ast_mutex_unlock(&pgsql_lock);
      ast_log(LOG_NOTICE, "cdr_pgsql configuration contains no global section, skipping module %s.\n",
         reload ? "reload" : "load");
      return -1;
   }

   if (!(tmp = ast_variable_retrieve(cfg, "global", "hostname"))) {
      ast_log(LOG_WARNING, "PostgreSQL server hostname not specified.  Assuming unix socket connection\n");
      tmp = "";   /* connect via UNIX-socket by default */
   }

   ast_free(pghostname);
   if (!(pghostname = ast_strdup(tmp))) {
      ast_config_destroy(cfg);
      ast_mutex_unlock(&pgsql_lock);
      return -1;
   }

   if (!(tmp = ast_variable_retrieve(cfg, "global", "dbname"))) {
      ast_log(LOG_WARNING, "PostgreSQL database not specified.  Assuming asterisk\n");
      tmp = "asteriskcdrdb";
   }

   ast_free(pgdbname);
   if (!(pgdbname = ast_strdup(tmp))) {
      ast_config_destroy(cfg);
      ast_mutex_unlock(&pgsql_lock);
      return -1;
   }

   if (!(tmp = ast_variable_retrieve(cfg, "global", "user"))) {
      ast_log(LOG_WARNING, "PostgreSQL database user not specified.  Assuming asterisk\n");
      tmp = "asterisk";
   }

   ast_free(pgdbuser);
   if (!(pgdbuser = ast_strdup(tmp))) {
      ast_config_destroy(cfg);
      ast_mutex_unlock(&pgsql_lock);
      return -1;
   }

   if (!(tmp = ast_variable_retrieve(cfg, "global", "password"))) {
      ast_log(LOG_WARNING, "PostgreSQL database password not specified.  Assuming blank\n");
      tmp = "";
   }

   ast_free(pgpassword);
   if (!(pgpassword = ast_strdup(tmp))) {
      ast_config_destroy(cfg);
      ast_mutex_unlock(&pgsql_lock);
      return -1;
   }

   if (!(tmp = ast_variable_retrieve(cfg, "global", "port"))) {
      ast_log(LOG_WARNING, "PostgreSQL database port not specified.  Using default 5432.\n");
      tmp = "5432";
   }

   ast_free(pgdbport);
   if (!(pgdbport = ast_strdup(tmp))) {
      ast_config_destroy(cfg);
      ast_mutex_unlock(&pgsql_lock);
      return -1;
   }

   if (!(tmp = ast_variable_retrieve(cfg, "global", "table"))) {
      ast_log(LOG_WARNING, "CDR table not specified.  Assuming cdr\n");
      tmp = "cdr";
   }

   ast_free(table);
   if (!(table = ast_strdup(tmp))) {
      ast_config_destroy(cfg);
      ast_mutex_unlock(&pgsql_lock);
      return -1;
   }

   if (!(tmp = ast_variable_retrieve(cfg, "global", "encoding"))) {
      ast_log(LOG_WARNING, "Encoding not specified.  Assuming LATIN9\n");
      tmp = "LATIN9";
   }

   ast_free(encoding);
   if (!(encoding = ast_strdup(tmp))) {
      ast_config_destroy(cfg);
      ast_mutex_unlock(&pgsql_lock);
      return -1;
   }

   if (!(tmp = ast_variable_retrieve(cfg, "global", "timezone"))) {
      tmp = "";
   }

   ast_free(tz);
   tz = NULL;

   if (!ast_strlen_zero(tmp) && !(tz = ast_strdup(tmp))) {
      ast_config_destroy(cfg);
      ast_mutex_unlock(&pgsql_lock);
      return -1;
   }

   if (option_debug) {
      if (ast_strlen_zero(pghostname)) {
         ast_debug(1, "using default unix socket\n");
      } else {
         ast_debug(1, "got hostname of %s\n", pghostname);
      }
      ast_debug(1, "got port of %s\n", pgdbport);
      ast_debug(1, "got user of %s\n", pgdbuser);
      ast_debug(1, "got dbname of %s\n", pgdbname);
      ast_debug(1, "got password of %s\n", pgpassword);
      ast_debug(1, "got sql table name of %s\n", table);
      ast_debug(1, "got encoding of %s\n", encoding);
      ast_debug(1, "got timezone of %s\n", tz);
   }

   conn = PQsetdbLogin(pghostname, pgdbport, NULL, NULL, pgdbname, pgdbuser, pgpassword);
   if (PQstatus(conn) != CONNECTION_BAD) {
      char sqlcmd[768];
      char *fname, *ftype, *flen, *fnotnull, *fdef;
      int i, rows, version;
      ast_debug(1, "Successfully connected to PostgreSQL database.\n");
      connected = 1;
      connect_time = time(NULL);
      records = 0;
      if (PQsetClientEncoding(conn, encoding)) {
#ifdef HAVE_PGSQL_pg_encoding_to_char
         ast_log(LOG_WARNING, "Failed to set encoding to '%s'.  Encoding set to default '%s'\n", encoding, pg_encoding_to_char(PQclientEncoding(conn)));
#else
         ast_log(LOG_WARNING, "Failed to set encoding to '%s'.  Encoding set to default.\n", encoding);
#endif
      }
      version = PQserverVersion(conn);

      if (version >= 70300) {
         char *schemaname, *tablename;
         if (strchr(table, '.')) {
            schemaname = ast_strdupa(table);
            tablename = strchr(schemaname, '.');
            *tablename++ = '\0';
         } else {
            schemaname = "";
            tablename = table;
         }

         /* Escape special characters in schemaname */
         if (strchr(schemaname, '\\') || strchr(schemaname, '\'')) {
            char *tmp = schemaname, *ptr;

            ptr = schemaname = alloca(strlen(tmp) * 2 + 1);
            for (; *tmp; tmp++) {
               if (strchr("\\'", *tmp)) {
                  *ptr++ = *tmp;
               }
               *ptr++ = *tmp;
            }
            *ptr = '\0';
         }
         /* Escape special characters in tablename */
         if (strchr(tablename, '\\') || strchr(tablename, '\'')) {
            char *tmp = tablename, *ptr;

            ptr = tablename = alloca(strlen(tmp) * 2 + 1);
            for (; *tmp; tmp++) {
               if (strchr("\\'", *tmp)) {
                  *ptr++ = *tmp;
               }
               *ptr++ = *tmp;
            }
            *ptr = '\0';
         }

         snprintf(sqlcmd, sizeof(sqlcmd), "SELECT a.attname, t.typname, a.attlen, a.attnotnull, d.adsrc, a.atttypmod FROM (((pg_catalog.pg_class c INNER JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace AND c.relname = '%s' AND n.nspname = %s%s%s) INNER JOIN pg_catalog.pg_attribute a ON (NOT a.attisdropped) AND a.attnum > 0 AND a.attrelid = c.oid) INNER JOIN pg_catalog.pg_type t ON t.oid = a.atttypid) LEFT OUTER JOIN pg_attrdef d ON a.atthasdef AND d.adrelid = a.attrelid AND d.adnum = a.attnum ORDER BY n.nspname, c.relname, attnum",
            tablename,
            ast_strlen_zero(schemaname) ? "" : "'", ast_strlen_zero(schemaname) ? "current_schema()" : schemaname, ast_strlen_zero(schemaname) ? "" : "'");
      } else {
         snprintf(sqlcmd, sizeof(sqlcmd), "SELECT a.attname, t.typname, a.attlen, a.attnotnull, d.adsrc, a.atttypmod FROM pg_class c, pg_type t, pg_attribute a LEFT OUTER JOIN pg_attrdef d ON a.atthasdef AND d.adrelid = a.attrelid AND d.adnum = a.attnum WHERE c.oid = a.attrelid AND a.atttypid = t.oid AND (a.attnum > 0) AND c.relname = '%s' ORDER BY c.relname, attnum", table);
      }
      /* Query the columns */
      result = PQexec(conn, sqlcmd);
      if (PQresultStatus(result) != PGRES_TUPLES_OK) {
         pgerror = PQresultErrorMessage(result);
         ast_log(LOG_ERROR, "Failed to query database columns: %s\n", pgerror);
         PQclear(result);
         unload_module();
         ast_mutex_unlock(&pgsql_lock);
         return AST_MODULE_LOAD_DECLINE;
      }

      rows = PQntuples(result);
      if (rows == 0) {
         ast_log(LOG_ERROR, "cdr_pgsql: Failed to query database columns. No columns found, does the table exist?\n");
         PQclear(result);
         unload_module();
         ast_mutex_unlock(&pgsql_lock);
         return AST_MODULE_LOAD_DECLINE;
      }

      /* Clear out the columns list. */
      empty_columns();

      for (i = 0; i < rows; i++) {
         fname = PQgetvalue(result, i, 0);
         ftype = PQgetvalue(result, i, 1);
         flen = PQgetvalue(result, i, 2);
         fnotnull = PQgetvalue(result, i, 3);
         fdef = PQgetvalue(result, i, 4);
         if (atoi(flen) == -1) {
            /* For varchar columns, the maximum length is encoded in a different field */
            flen = PQgetvalue(result, i, 5);
         }
         ast_verb(4, "Found column '%s' of type '%s'\n", fname, ftype);
         cur = ast_calloc(1, sizeof(*cur) + strlen(fname) + strlen(ftype) + 2);
         if (cur) {
            sscanf(flen, "%30d", &cur->len);
            cur->name = (char *)cur + sizeof(*cur);
            cur->type = (char *)cur + sizeof(*cur) + strlen(fname) + 1;
            strcpy(cur->name, fname);
            strcpy(cur->type, ftype);
            if (*fnotnull == 't') {
               cur->notnull = 1;
            } else {
               cur->notnull = 0;
            }
            if (!ast_strlen_zero(fdef)) {
               cur->hasdefault = 1;
            } else {
               cur->hasdefault = 0;
            }
            AST_RWLIST_WRLOCK(&psql_columns);
            AST_RWLIST_INSERT_TAIL(&psql_columns, cur, list);
            AST_RWLIST_UNLOCK(&psql_columns);
         }
      }
      PQclear(result);
   } else {
      pgerror = PQerrorMessage(conn);
      ast_log(LOG_ERROR, "Unable to connect to database server %s.  CALLS WILL NOT BE LOGGED!!\n", pghostname);
      ast_log(LOG_ERROR, "Reason: %s\n", pgerror);
      connected = 0;
   }

   ast_config_destroy(cfg);

   ast_mutex_unlock(&pgsql_lock);
   return 0;
}

static int load_module(void)
{
   ast_cli_register_multiple(cdr_pgsql_status_cli, sizeof(cdr_pgsql_status_cli) / sizeof(struct ast_cli_entry));
   if (config_module(0)) {
      return AST_MODULE_LOAD_DECLINE;
   }
   return ast_cdr_register(name, ast_module_info->description, pgsql_log)
      ? AST_MODULE_LOAD_DECLINE : 0;
}

static int reload(void)
{
   return config_module(1);
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PostgreSQL CDR Backend",
      .load = load_module,
      .unload = unload_module,
      .reload = reload,
      .load_pri = AST_MODPRI_CDR_DRIVER,
          );