postgresql/src/test/modules/test_session_hooks/test_session_hooks.c

156 lines
3.5 KiB
C

/* -------------------------------------------------------------------------
*
* test_session_hooks.c
* Code for testing start and end session hooks.
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/test/modules/test_session_hooks/test_session_hooks.c
*
* -------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/parallel.h"
#include "access/xact.h"
#include "commands/dbcommands.h"
#include "executor/spi.h"
#include "lib/stringinfo.h"
#include "miscadmin.h"
#include "tcop/tcopprot.h"
#include "utils/snapmgr.h"
#include "utils/builtins.h"
PG_MODULE_MAGIC;
/* Entry point of library loading/unloading */
void _PG_init(void);
void _PG_fini(void);
/* GUC variables */
static char *session_hook_username = "postgres";
/* Previous hooks on stack */
static session_start_hook_type prev_session_start_hook = NULL;
static session_end_hook_type prev_session_end_hook = NULL;
static void
register_session_hook(const char *hook_at)
{
const char *username;
StartTransactionCommand();
SPI_connect();
PushActiveSnapshot(GetTransactionSnapshot());
/* Check the current user validity */
username = GetUserNameFromId(GetUserId(), false);
/* Register log just for configured username */
if (strcmp(username, session_hook_username) == 0)
{
const char *dbname;
int ret;
StringInfoData buf;
dbname = get_database_name(MyDatabaseId);
initStringInfo(&buf);
appendStringInfo(&buf, "INSERT INTO session_hook_log (dbname, username, hook_at) ");
appendStringInfo(&buf, "VALUES (%s, %s, %s);",
quote_literal_cstr(dbname),
quote_literal_cstr(username),
quote_literal_cstr(hook_at));
ret = SPI_exec(buf.data, 0);
if (ret != SPI_OK_INSERT)
elog(ERROR, "SPI_execute failed: error code %d", ret);
}
SPI_finish();
PopActiveSnapshot();
CommitTransactionCommand();
}
/* sample session start hook function */
static void
sample_session_start_hook(void)
{
if (prev_session_start_hook)
prev_session_start_hook();
/* consider only normal backends */
if (MyBackendId == InvalidBackendId)
return;
/* consider backends connected to a database */
if (!OidIsValid(MyDatabaseId))
return;
/* no parallel workers */
if (IsParallelWorker())
return;
register_session_hook("START");
}
/* sample session end hook function */
static void
sample_session_end_hook(void)
{
if (prev_session_end_hook)
prev_session_end_hook();
/* consider only normal backends */
if (MyBackendId == InvalidBackendId)
return;
/* consider backends connected to a database */
if (!OidIsValid(MyDatabaseId))
return;
/* no parallel workers */
if (IsParallelWorker())
return;
register_session_hook("END");
}
/*
* Module load callback
*/
void
_PG_init(void)
{
/* Save previous hooks */
prev_session_start_hook = session_start_hook;
prev_session_end_hook = session_end_hook;
/* Set new hooks */
session_start_hook = sample_session_start_hook;
session_end_hook = sample_session_end_hook;
/* Load GUCs */
DefineCustomStringVariable("test_session_hooks.username",
"Username to register log on session start or end",
NULL,
&session_hook_username,
"postgres",
PGC_SIGHUP,
0, NULL, NULL, NULL);
}
/*
* Module unload callback
*/
void
_PG_fini(void)
{
/* Uninstall hooks */
session_start_hook = prev_session_start_hook;
session_end_hook = prev_session_end_hook;
}