pq_connect.c File Reference

functions to connect to libpq (PostGres) More...

#include "platform.h"
#include "pq.h"

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Functions
static void	pq_notice_receiver_cb (void *arg, const PGresult *res)
	Function called by libpq whenever it wants to log something. More...
static void	pq_notice_processor_cb (void *arg, const char *message)
	Function called by libpq whenever it wants to log something. More...
struct GNUNET_PQ_Context *	GNUNET_PQ_connect (const char *config_str, const struct GNUNET_PQ_ExecuteStatement *es, const struct GNUNET_PQ_PreparedStatement *ps)
	Create a connection to the Postgres database using config_str for the configuration. More...
void	GNUNET_PQ_reconnect_if_down (struct GNUNET_PQ_Context *db)
	Reinitialize the database db if the connection is down. More...
void	GNUNET_PQ_reconnect (struct GNUNET_PQ_Context *db)
	Reinitialize the database db. More...
struct GNUNET_PQ_Context *	GNUNET_PQ_connect_with_cfg (const struct GNUNET_CONFIGURATION_Handle *cfg, const char *section, const struct GNUNET_PQ_ExecuteStatement *es, const struct GNUNET_PQ_PreparedStatement *ps)
	Connect to a postgres database using the configuration option "CONFIG" in section. More...
void	GNUNET_PQ_disconnect (struct GNUNET_PQ_Context *db)
	Disconnect from the database, destroying the prepared statements and releasing other associated resources. More...

Detailed Description

functions to connect to libpq (PostGres)

Author

Christian Grothoff

Definition in file pq_connect.c.

Function Documentation

pq_notice_receiver_cb()

static void pq_notice_receiver_cb ( void *  arg, const PGresult *  res  )

static

Function called by libpq whenever it wants to log something.

We already log whenever we care, so this function does nothing and merely exists to silence the libpq logging.

Parameters

arg	the SQL connection that was used
res	information about some libpq event

Definition at line 38 of file pq_connect.c.

Referenced by GNUNET_PQ_reconnect().

{
  /* do nothing, intentionally */
  (void) arg;
  (void) res;
}

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pq_notice_processor_cb()

static void pq_notice_processor_cb ( void *  arg, const char *  message  )

static

Function called by libpq whenever it wants to log something.

We log those using the GNUnet logger.

Parameters

arg	the SQL connection that was used
message	information about some libpq event

Definition at line 55 of file pq_connect.c.

References GNUNET_ERROR_TYPE_INFO, and GNUNET_log_from.

Referenced by GNUNET_PQ_reconnect().

{
  (void) arg;
  GNUNET_log_from (GNUNET_ERROR_TYPE_INFO,
                   "pq",
                   "%s",
                   message);
}

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GNUNET_PQ_connect()

struct GNUNET_PQ_Context* GNUNET_PQ_connect	(	const char *	config_str,
		const struct GNUNET_PQ_ExecuteStatement *	es,
		const struct GNUNET_PQ_PreparedStatement *	ps
	)

Create a connection to the Postgres database using config_str for the configuration.

Initialize logging via GNUnet's log routines and disable Postgres's logger. Also ensures that the statements in es are executed whenever we (re)connect to the database, and that the prepared statements in ps are "ready". If statements in fail that were created with GNUNET_PQ_make_execute(), then the entire operation fails.

The caller MUST ensure that es and ps remain allocated and initialized in memory until GNUNET_PQ_disconnect() is called, as they may be needed repeatedly and no copy will be made.

Parameters

config_str	configuration to use
es	GNUNET_PQ_PREPARED_STATEMENT_END-terminated array of statements to execute upon EACH connection, can be NULL
ps	array of prepared statements to prepare, can be NULL

Returns

NULL on error

Definition at line 86 of file pq_connect.c.

References GNUNET_PQ_Context::config_str, GNUNET_PQ_Context::conn, db, GNUNET_PQ_Context::es, GNUNET_free, GNUNET_new, GNUNET_new_array, GNUNET_PQ_reconnect(), GNUNET_strdup, name, and GNUNET_PQ_Context::ps.

Referenced by GNUNET_PQ_connect_with_cfg().

{
  struct GNUNET_PQ_Context *db;
  unsigned int elen = 0;
  unsigned int plen = 0;

  if (NULL != es)
    while (NULL != es[elen].sql)
      elen++;
  if (NULL != ps)
    while (NULL != ps[plen].name)
      plen++;

  db = GNUNET_new (struct GNUNET_PQ_Context);
  db->config_str = GNUNET_strdup (config_str);
  if (0 != elen)
  {
    db->es = GNUNET_new_array (elen + 1,
                               struct GNUNET_PQ_ExecuteStatement);
    memcpy (db->es,
            es,
            elen * sizeof (struct GNUNET_PQ_ExecuteStatement));
  }
  if (0 != plen)
  {
    db->ps = GNUNET_new_array (plen + 1,
                               struct GNUNET_PQ_PreparedStatement);
    memcpy (db->ps,
            ps,
            plen * sizeof (struct GNUNET_PQ_PreparedStatement));
  }
  GNUNET_PQ_reconnect (db);
  if (NULL == db->conn)
  {
    GNUNET_free (db->config_str);
    GNUNET_free (db);
    return NULL;
  }
  return db;
}

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GNUNET_PQ_reconnect_if_down()

void GNUNET_PQ_reconnect_if_down

(

struct GNUNET_PQ_Context *

db

)

Reinitialize the database db if the connection is down.

Parameters

db	database connection to reinitialize

Definition at line 136 of file pq_connect.c.

References GNUNET_PQ_Context::conn, and GNUNET_PQ_reconnect().

{
  if (CONNECTION_BAD != PQstatus (db->conn))
    return;
  GNUNET_PQ_reconnect (db);
}

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GNUNET_PQ_reconnect()

void GNUNET_PQ_reconnect

(

struct GNUNET_PQ_Context *

db

)

Reinitialize the database db.

Parameters

db	database connection to reinitialize

Definition at line 150 of file pq_connect.c.

References GNUNET_PQ_Context::config_str, GNUNET_PQ_Context::conn, GNUNET_PQ_Context::es, GNUNET_ERROR_TYPE_ERROR, GNUNET_log_from, GNUNET_OK, GNUNET_PQ_exec_statements(), GNUNET_PQ_prepare_statements(), pq_notice_processor_cb(), pq_notice_receiver_cb(), and GNUNET_PQ_Context::ps.

Referenced by GNUNET_PQ_connect(), GNUNET_PQ_eval_result(), GNUNET_PQ_exec_prepared(), and GNUNET_PQ_reconnect_if_down().

{
  if (NULL != db->conn)
    PQfinish (db->conn);
  db->conn = PQconnectdb (db->config_str);
  if ((NULL == db->conn) ||
      (CONNECTION_OK != PQstatus (db->conn)))
  {
    GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR,
                     "pq",
                     "Database connection to '%s' failed: %s\n",
                     db->config_str,
                     (NULL != db->conn) ?
                     PQerrorMessage (db->conn)
                     : "PQconnectdb returned NULL");
    if (NULL != db->conn)
    {
      PQfinish (db->conn);
      db->conn = NULL;
    }
    return;
  }
  PQsetNoticeReceiver (db->conn,
                       &pq_notice_receiver_cb,
                       db);
  PQsetNoticeProcessor (db->conn,
                        &pq_notice_processor_cb,
                        db);
  if ( (NULL != db->es) &&
       (GNUNET_OK !=
        GNUNET_PQ_exec_statements (db,
                                   db->es)) )
  {
    PQfinish (db->conn);
    db->conn = NULL;
    return;
  }
  if ( (NULL != db->ps) &&
       (GNUNET_OK !=
        GNUNET_PQ_prepare_statements (db,
                                      db->ps)) )
  {
    PQfinish (db->conn);
    db->conn = NULL;
    return;
  }
}

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GNUNET_PQ_connect_with_cfg()

struct GNUNET_PQ_Context* GNUNET_PQ_connect_with_cfg	(	const struct GNUNET_CONFIGURATION_Handle *	cfg,
		const char *	section,
		const struct GNUNET_PQ_ExecuteStatement *	es,
		const struct GNUNET_PQ_PreparedStatement *	ps
	)

Connect to a postgres database using the configuration option "CONFIG" in section.

Also ensures that the statements in es are executed whenever we (re)connect to the database, and that the prepared statements in ps are "ready".

The caller MUST ensure that es and ps remain allocated and initialized in memory until GNUNET_PQ_disconnect() is called, as they may be needed repeatedly and no copy will be made.

Parameters

cfg	configuration
section	configuration section to use to get Postgres configuration options
es	GNUNET_PQ_PREPARED_STATEMENT_END-terminated array of statements to execute upon EACH connection, can be NULL
ps	array of prepared statements to prepare, can be NULL

Returns

the postgres handle, NULL on error

Definition at line 217 of file pq_connect.c.

References db, GNUNET_CONFIGURATION_get_value_string(), GNUNET_free_non_null, GNUNET_OK, and GNUNET_PQ_connect().

Referenced by database_setup(), and init_connection().

{
  struct GNUNET_PQ_Context *db;
  char *conninfo;

  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_string (cfg,
                                             section,
                                             "CONFIG",
                                             &conninfo))
    conninfo = NULL;
  db = GNUNET_PQ_connect (conninfo == NULL ? "" : conninfo,
                          es,
                          ps);
  GNUNET_free_non_null (conninfo);
  return db;
}

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GNUNET_PQ_disconnect()

void GNUNET_PQ_disconnect

(

struct GNUNET_PQ_Context *

db

)

Disconnect from the database, destroying the prepared statements and releasing other associated resources.

Parameters

db	database handle to disconnect (will be free'd)

Definition at line 246 of file pq_connect.c.

References GNUNET_PQ_Context::conn, GNUNET_PQ_Context::es, GNUNET_free, GNUNET_free_non_null, and GNUNET_PQ_Context::ps.

Referenced by database_shutdown(), libgnunet_plugin_datacache_postgres_done(), and libgnunet_plugin_datastore_postgres_done().

{
  GNUNET_free_non_null (db->es);
  GNUNET_free_non_null (db->ps);
  PQfinish (db->conn);
  GNUNET_free (db);
}

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