Wed Aug 20 06:37:03 2008

Asterisk developer's documentation

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res_odbc.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * res_odbc.c <ODBC resource manager>
 * Copyright (C) 2004 - 2005 Anthony Minessale II <anthmct@yahoo.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 ODBC resource manager
 * 
 * \arg See also: \ref cdr_odbc
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 59299 $")

#include "asterisk/file.h"
#include "asterisk/logger.h"
#include "asterisk/channel.h"
#include "asterisk/config.h"
#include "asterisk/options.h"
#include "asterisk/pbx.h"
#include "asterisk/module.h"
#include "asterisk/cli.h"
#include "asterisk/lock.h"
#include "asterisk/res_odbc.h"
#define MAX_ODBC_HANDLES 25

struct odbc_list
{
   char name[80];
   odbc_obj *obj;
   int used;
};

static struct odbc_list ODBC_REGISTRY[MAX_ODBC_HANDLES];


static void odbc_destroy(void)
{
   int x = 0;

   for (x = 0; x < MAX_ODBC_HANDLES; x++) {
      if (ODBC_REGISTRY[x].obj) {
         destroy_odbc_obj(&ODBC_REGISTRY[x].obj);
         ODBC_REGISTRY[x].obj = NULL;
      }
   }
}

static odbc_obj *odbc_read(struct odbc_list *registry, const char *name)
{
   int x = 0;
   for (x = 0; x < MAX_ODBC_HANDLES; x++) {
      if (registry[x].used && !strcmp(registry[x].name, name)) {
         return registry[x].obj;
      }
   }
   return NULL;
}

static int odbc_write(struct odbc_list *registry, char *name, odbc_obj *obj)
{
   int x = 0;
   for (x = 0; x < MAX_ODBC_HANDLES; x++) {
      if (!registry[x].used) {
         ast_copy_string(registry[x].name, name, sizeof(registry[x].name));
         registry[x].obj = obj;
         registry[x].used = 1;
         return 1;
      }
   }
   return 0;
}

static void odbc_init(void)
{
   int x = 0;
   for (x = 0; x < MAX_ODBC_HANDLES; x++) {
      memset(&ODBC_REGISTRY[x], 0, sizeof(struct odbc_list));
   }
}

static char *tdesc = "ODBC Resource";
/* internal stuff */

SQLHSTMT odbc_prepare_and_execute(odbc_obj *obj, SQLHSTMT (*prepare_cb)(odbc_obj *obj, void *data), void *data)
{
   int res = 0, i, attempt;
   SQLINTEGER nativeerror=0, numfields=0;
   SQLSMALLINT diagbytes=0;
   unsigned char state[10], diagnostic[256];
   SQLHSTMT stmt;

   for (attempt = 0; attempt < 2; attempt++) {
      /* This prepare callback may do more than just prepare -- it may also
       * bind parameters, bind results, etc.  The real key, here, is that
       * when we disconnect, all handles become invalid for most databases.
       * We must therefore redo everything when we establish a new
       * connection. */
      stmt = prepare_cb(obj, data);

      if (stmt) {
         res = SQLExecute(stmt);
         if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO) && (res != SQL_NO_DATA)) {
            if (res == SQL_ERROR) {
               SQLGetDiagField(SQL_HANDLE_STMT, stmt, 1, SQL_DIAG_NUMBER, &numfields, SQL_IS_INTEGER, &diagbytes);
               for (i=0; i< numfields + 1; i++) {
                  SQLGetDiagRec(SQL_HANDLE_STMT, stmt, i + 1, state, &nativeerror, diagnostic, sizeof(diagnostic), &diagbytes);
                  ast_log(LOG_WARNING, "SQL Execute returned an error %d: %s: %s (%d)\n", res, state, diagnostic, diagbytes);
                  if (i > 10) {
                     ast_log(LOG_WARNING, "Oh, that was good.  There are really %d diagnostics?\n", (int)numfields);
                     break;
                  }
               }
            }

            ast_log(LOG_WARNING, "SQL Execute error %d! Attempting a reconnect...\n", res);
            SQLFreeHandle(SQL_HANDLE_STMT, stmt);
            stmt = NULL;

            ast_mutex_lock(&obj->lock);
            obj->up = 0;
            ast_mutex_unlock(&obj->lock);
            odbc_obj_disconnect(obj);
            odbc_obj_connect(obj);
            continue;
         }
         break;
      }
   }

   return stmt;
}

int odbc_smart_execute(odbc_obj *obj, SQLHSTMT stmt) 
{
   int res = 0, i;
   SQLINTEGER nativeerror=0, numfields=0;
   SQLSMALLINT diagbytes=0;
   unsigned char state[10], diagnostic[256];

   res = SQLExecute(stmt);
   if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO) && (res != SQL_NO_DATA)) {
      if (res == SQL_ERROR) {
         SQLGetDiagField(SQL_HANDLE_STMT, stmt, 1, SQL_DIAG_NUMBER, &numfields, SQL_IS_INTEGER, &diagbytes);
         for (i=0; i< numfields + 1; i++) {
            SQLGetDiagRec(SQL_HANDLE_STMT, stmt, i + 1, state, &nativeerror, diagnostic, sizeof(diagnostic), &diagbytes);
            ast_log(LOG_WARNING, "SQL Execute returned an error %d: %s: %s (%d)\n", res, state, diagnostic, diagbytes);
            if (i > 10) {
               ast_log(LOG_WARNING, "Oh, that was good.  There are really %d diagnostics?\n", (int)numfields);
               break;
            }
         }
      }
/*
      ast_log(LOG_WARNING, "SQL Execute error %d! Attempting a reconnect...\n", res);
      ast_mutex_lock(&obj->lock);
      obj->up = 0;
      ast_mutex_unlock(&obj->lock);
      odbc_obj_disconnect(obj);
      odbc_obj_connect(obj);
      res = SQLExecute(stmt);
*/
   }
   
   return res;
}


int odbc_smart_direct_execute(odbc_obj *obj, SQLHSTMT stmt, char *sql) 
{
   int res = 0;

   res = SQLExecDirect (stmt, (unsigned char *)sql, SQL_NTS);
   if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
      ast_log(LOG_WARNING, "SQL Execute error! Attempting a reconnect...\n");
      ast_mutex_lock(&obj->lock);
      obj->up = 0;
      ast_mutex_unlock(&obj->lock);
      odbc_obj_disconnect(obj);
      odbc_obj_connect(obj);
      res = SQLExecDirect (stmt, (unsigned char *)sql, SQL_NTS);
   }
   
   return res;
}

int odbc_sanity_check(odbc_obj *obj) 
{
   char *test_sql = "select 1";
   SQLHSTMT stmt;
   int res = 0;

   ast_mutex_lock(&obj->lock);
   if(obj->up) { /* so you say... let's make sure */
      res = SQLAllocHandle (SQL_HANDLE_STMT, obj->con, &stmt);
      if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
         obj->up = 0; /* Liar!*/
      } else {
         res = SQLPrepare(stmt, (unsigned char *)test_sql, SQL_NTS);
         if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
            obj->up = 0; /* Liar!*/
         } else {
            res = SQLExecute(stmt);
            if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
               obj->up = 0; /* Liar!*/
            }
         }
      }
      SQLFreeHandle (SQL_HANDLE_STMT, stmt);
   }
   ast_mutex_unlock(&obj->lock);

   if(!obj->up) { /* Try to reconnect! */
      ast_log(LOG_WARNING, "Connection is down attempting to reconnect...\n");
      odbc_obj_disconnect(obj);
      odbc_obj_connect(obj);
   }
   return obj->up;
}

static int load_odbc_config(void)
{
   static char *cfg = "res_odbc.conf";
   struct ast_config *config;
   struct ast_variable *v;
   char *cat, *dsn, *username, *password;
   int enabled;
   int connect = 0;

   odbc_obj *obj;

   config = ast_config_load(cfg);
   if (config) {
      for (cat = ast_category_browse(config, NULL); cat; cat=ast_category_browse(config, cat)) {
         if (!strcmp(cat, "ENV")) {
            for (v = ast_variable_browse(config, cat); v; v = v->next) {
               setenv(v->name, v->value, 1);
            }

            cat = ast_category_browse(config, cat);
         }

         dsn = username = password = NULL;
         enabled = 1;
         connect = 0;
         for (v = ast_variable_browse(config, cat); v; v = v->next) {
            if (!strcmp(v->name, "enabled"))
               enabled = ast_true(v->value);
            if (!strcmp(v->name, "pre-connect"))
               connect = ast_true(v->value);
            if (!strcmp(v->name, "dsn"))
               dsn = v->value;
            if (!strcmp(v->name, "username"))
               username = v->value;
            if (!strcmp(v->name, "password"))
               password = v->value;
         }

         if (enabled && dsn) {
            obj = new_odbc_obj(cat, dsn, username, password);
            if (obj) {
               register_odbc_obj(cat, obj);
               ast_log(LOG_NOTICE, "registered database handle '%s' dsn->[%s]\n", cat, obj->dsn);
               if (connect) {
                  odbc_obj_connect(obj);
               }
            } else {
               ast_log(LOG_WARNING, "Addition of obj %s failed.\n", cat);
            }

         }
      }
      ast_config_destroy(config);
   }
   return 0;
}

int odbc_dump_fd(int fd, odbc_obj *obj)
{
   /* make sure the connection is up before we lie to our master.*/
   odbc_sanity_check(obj);
   ast_cli(fd, "Name: %s\nDSN: %s\nConnected: %s\n\n", obj->name, obj->dsn, obj->up ? "yes" : "no");
   return 0;
}

static int odbc_connect_usage(int fd)
{
   ast_cli(fd, "usage odbc connect <DSN>\n");
   return 0;
}

static int odbc_disconnect_usage(int fd)
{
   ast_cli(fd, "usage odbc disconnect <DSN>\n");
   return 0;
}

static int odbc_show_command(int fd, int argc, char **argv)
{
   odbc_obj *obj;
   int x = 0;
   
   if (!strcmp(argv[1], "show")) {
      if (!argv[2] || (argv[2] && !strcmp(argv[2], "all"))) {
         for (x = 0; x < MAX_ODBC_HANDLES; x++) {
            if (!ODBC_REGISTRY[x].used)
               break;
            if (ODBC_REGISTRY[x].obj)
               odbc_dump_fd(fd, ODBC_REGISTRY[x].obj);
         }
      } else {
         obj = odbc_read(ODBC_REGISTRY, argv[2]);
         if (obj)
            odbc_dump_fd(fd, obj);
      }
   }
   return 0;
}

static int odbc_disconnect_command(int fd, int argc, char **argv)
{
   odbc_obj *obj;
   if (!strcmp(argv[1], "disconnect")) {
      if (!argv[2])
         return odbc_disconnect_usage(fd);

      obj = odbc_read(ODBC_REGISTRY, argv[2]);
      if (obj) {
         odbc_obj_disconnect(obj);
      }
   } 
   return 0;
}

static int odbc_connect_command(int fd, int argc, char **argv)
{
   odbc_obj *obj;
   if (!argv[1])
      return odbc_connect_usage(fd);

   if (!strcmp(argv[1], "connect") || !strcmp(argv[1], "disconnect")) {
      if (!argv[2])
         return odbc_connect_usage(fd);

      obj = odbc_read(ODBC_REGISTRY, argv[2]);
      if (obj) {
         odbc_obj_connect(obj);
      }
   }
   return 0;
}


static char connect_usage[] =
"Usage: odbc connect <DSN>\n"
"       Connect to ODBC DSN\n";

static char disconnect_usage[] =
"Usage: odbc connect <DSN>\n"
"       Disconnect from ODBC DSN\n";

static char show_usage[] =
"Usage: odbc show {DSN}\n"
"       Show ODBC {DSN}\n"
"       Specifying DSN will show that DSN else, all DSNs are shown\n";

static struct ast_cli_entry odbc_connect_struct =
        { { "odbc", "connect", NULL }, odbc_connect_command, "Connect to ODBC DSN", connect_usage };


static struct ast_cli_entry odbc_disconnect_struct =
        { { "odbc", "disconnect", NULL }, odbc_disconnect_command, "Disconnect from ODBC DSN", disconnect_usage };

static struct ast_cli_entry odbc_show_struct =
        { { "odbc", "show", NULL }, odbc_show_command, "Show ODBC DSN(s)", show_usage };

/* api calls */

int register_odbc_obj(char *name, odbc_obj *obj)
{
   if (obj != NULL)
      return odbc_write(ODBC_REGISTRY, name, obj);
   return 0;
}

odbc_obj *fetch_odbc_obj(const char *name, int check)
{
   odbc_obj *obj = NULL;
   if((obj = (odbc_obj *) odbc_read(ODBC_REGISTRY, name))) {
      if(check)
         odbc_sanity_check(obj);
   }
   return obj;
}

odbc_obj *new_odbc_obj(char *name, char *dsn, char *username, char *password)
{
   static odbc_obj *new;

   if (!(new = calloc(1, sizeof(*new))) || 
       !(new->name = malloc(strlen(name) + 1)) || 
       !(new->dsn = malloc(strlen(dsn) + 1)))
         goto cleanup;

   if (username) {
      if (!(new->username = malloc(strlen(username) + 1)))
         goto cleanup;
      strcpy(new->username, username);
   }

   if (password) {
      if (!(new->password = malloc(strlen(password) + 1)))
         goto cleanup;
      strcpy(new->password, password);
   }

   strcpy(new->name, name);
   strcpy(new->dsn, dsn);
   new->env = SQL_NULL_HANDLE;
   new->up = 0;
   ast_mutex_init(&new->lock);
   return new;

cleanup:
   if (new) {
      free(new->name);
      free(new->dsn);
      free(new->username);
      free(new->password);

      free(new);  
   }

   return NULL;
}

void destroy_odbc_obj(odbc_obj **obj)
{
   odbc_obj_disconnect(*obj);

   ast_mutex_lock(&(*obj)->lock);
   SQLFreeHandle(SQL_HANDLE_STMT, (*obj)->stmt);
   SQLFreeHandle(SQL_HANDLE_DBC, (*obj)->con);
   SQLFreeHandle(SQL_HANDLE_ENV, (*obj)->env);

   free((*obj)->name);
   free((*obj)->dsn);
   if ((*obj)->username)
      free((*obj)->username);
   if ((*obj)->password)
      free((*obj)->password);
   ast_mutex_unlock(&(*obj)->lock);
   ast_mutex_destroy(&(*obj)->lock);
   free(*obj);
}

odbc_status odbc_obj_disconnect(odbc_obj *obj)
{
   int res;
   ast_mutex_lock(&obj->lock);

   res = SQLDisconnect(obj->con);


   if (res == ODBC_SUCCESS) {
      ast_log(LOG_WARNING, "res_odbc: disconnected %d from %s [%s]\n", res, obj->name, obj->dsn);
   } else {
      ast_log(LOG_WARNING, "res_odbc: %s [%s] already disconnected\n",
      obj->name, obj->dsn);
   }
   obj->up = 0;
   ast_mutex_unlock(&obj->lock);
   return ODBC_SUCCESS;
}

odbc_status odbc_obj_connect(odbc_obj *obj)
{
   int res;
   SQLINTEGER err;
   short int mlen;
   unsigned char msg[200], stat[10];

   ast_mutex_lock(&obj->lock);

   if (obj->env == SQL_NULL_HANDLE) {
      res = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &obj->env);

      if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
         if (option_verbose > 3)
            ast_log(LOG_WARNING, "res_odbc: Error AllocHandle\n");
         ast_mutex_unlock(&obj->lock);
         return ODBC_FAIL;
      }

      res = SQLSetEnvAttr(obj->env, SQL_ATTR_ODBC_VERSION, (void *) SQL_OV_ODBC3, 0);

      if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
         if (option_verbose > 3)
            ast_log(LOG_WARNING, "res_odbc: Error SetEnv\n");
         SQLFreeHandle(SQL_HANDLE_ENV, obj->env);
         ast_mutex_unlock(&obj->lock);
         return ODBC_FAIL;
      }

      res = SQLAllocHandle(SQL_HANDLE_DBC, obj->env, &obj->con);

      if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {

         if (option_verbose > 3)
            ast_log(LOG_WARNING, "res_odbc: Error AllocHDB %d\n", res);
         SQLFreeHandle(SQL_HANDLE_ENV, obj->env);

         ast_mutex_unlock(&obj->lock);
         return ODBC_FAIL;
      }
      SQLSetConnectAttr(obj->con, SQL_LOGIN_TIMEOUT, (SQLPOINTER *) 10, 0);
   }
   if(obj->up) {
      odbc_obj_disconnect(obj);
      ast_log(LOG_NOTICE,"Re-connecting %s\n", obj->name);
   }

   ast_log(LOG_NOTICE, "Connecting %s\n", obj->name);

   res = SQLConnect(obj->con,
         (SQLCHAR *) obj->dsn, SQL_NTS,
         (SQLCHAR *) obj->username, SQL_NTS,
         (SQLCHAR *) obj->password, SQL_NTS);

   if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
      SQLGetDiagRec(SQL_HANDLE_DBC, obj->con, 1, stat, &err, msg, 100, &mlen);
      SQLFreeHandle(SQL_HANDLE_ENV, obj->env);
      ast_mutex_unlock(&obj->lock);
      ast_log(LOG_WARNING, "res_odbc: Error SQLConnect=%d errno=%d %s\n", res, (int)err, msg);
      return ODBC_FAIL;
   } else {

      ast_log(LOG_NOTICE, "res_odbc: Connected to %s [%s]\n", obj->name, obj->dsn);
      obj->up = 1;
   }

   ast_mutex_unlock(&obj->lock);
   return ODBC_SUCCESS;
}

STANDARD_LOCAL_USER;

LOCAL_USER_DECL;

int unload_module(void)
{
   STANDARD_HANGUP_LOCALUSERS;
   odbc_destroy();
   ast_cli_unregister(&odbc_disconnect_struct);
   ast_cli_unregister(&odbc_connect_struct);
   ast_cli_unregister(&odbc_show_struct);
   ast_log(LOG_NOTICE, "res_odbc unloaded.\n");
   return 0;
}

int load_module(void)
{
   odbc_init();
   load_odbc_config();
   ast_cli_register(&odbc_disconnect_struct);
   ast_cli_register(&odbc_connect_struct);
   ast_cli_register(&odbc_show_struct);
   ast_log(LOG_NOTICE, "res_odbc loaded.\n");
   return 0;
}

char *description(void)
{
   return tdesc;
}

int usecount(void)
{
   int res;
   STANDARD_USECOUNT(res);
   return res;
}

char *key()
{
   return ASTERISK_GPL_KEY;
}

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