Tom Lane 21d36747d4 Fix ancient bug in ecpg's pthread_once() emulation for Windows.
We must not set the "done" flag until after we've executed the
initialization function.  Otherwise, other threads can fall through
the initial unlocked test before initialization is really complete.

This has been seen to cause rare failures of ecpg's thread/descriptor
test, and it could presumably cause other sorts of misbehavior in
threaded ECPG-using applications, since ecpglib relies on
pthread_once() in several places.

Diagnosis and patch by me, based on investigation by Alexander Lakhin.
Back-patch to all supported branches (the bug dates to 2007).

Discussion: https://postgr.es/m/16685-d6cd241872c101d3@postgresql.org
2020-10-24 13:12:08 -04:00

588 lines
12 KiB
C

/* src/interfaces/ecpg/ecpglib/misc.c */
#define POSTGRES_ECPG_INTERNAL
#include "postgres_fe.h"
#include <limits.h>
#include <unistd.h>
#include "ecpg-pthread-win32.h"
#include "ecpgerrno.h"
#include "ecpglib.h"
#include "ecpglib_extern.h"
#include "ecpgtype.h"
#include "pg_config_paths.h"
#include "pgtypes_date.h"
#include "pgtypes_interval.h"
#include "pgtypes_numeric.h"
#include "pgtypes_timestamp.h"
#include "sqlca.h"
#ifndef LONG_LONG_MIN
#ifdef LLONG_MIN
#define LONG_LONG_MIN LLONG_MIN
#else
#define LONG_LONG_MIN LONGLONG_MIN
#endif /* LLONG_MIN */
#endif /* LONG_LONG_MIN */
bool ecpg_internal_regression_mode = false;
static struct sqlca_t sqlca_init =
{
{
'S', 'Q', 'L', 'C', 'A', ' ', ' ', ' '
},
sizeof(struct sqlca_t),
0,
{
0,
{
0
}
},
{
'N', 'O', 'T', ' ', 'S', 'E', 'T', ' '
},
{
0, 0, 0, 0, 0, 0
},
{
0, 0, 0, 0, 0, 0, 0, 0
},
{
'0', '0', '0', '0', '0'
}
};
#ifdef ENABLE_THREAD_SAFETY
static pthread_key_t sqlca_key;
static pthread_once_t sqlca_key_once = PTHREAD_ONCE_INIT;
#else
static struct sqlca_t sqlca =
{
{
'S', 'Q', 'L', 'C', 'A', ' ', ' ', ' '
},
sizeof(struct sqlca_t),
0,
{
0,
{
0
}
},
{
'N', 'O', 'T', ' ', 'S', 'E', 'T', ' '
},
{
0, 0, 0, 0, 0, 0
},
{
0, 0, 0, 0, 0, 0, 0, 0
},
{
'0', '0', '0', '0', '0'
}
};
#endif
#ifdef ENABLE_THREAD_SAFETY
static pthread_mutex_t debug_mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t debug_init_mutex = PTHREAD_MUTEX_INITIALIZER;
#endif
static int simple_debug = 0;
static FILE *debugstream = NULL;
void
ecpg_init_sqlca(struct sqlca_t *sqlca)
{
memcpy((char *) sqlca, (char *) &sqlca_init, sizeof(struct sqlca_t));
}
bool
ecpg_init(const struct connection *con, const char *connection_name, const int lineno)
{
struct sqlca_t *sqlca = ECPGget_sqlca();
if (sqlca == NULL)
{
ecpg_raise(lineno, ECPG_OUT_OF_MEMORY, ECPG_SQLSTATE_ECPG_OUT_OF_MEMORY,
NULL);
return false;
}
ecpg_init_sqlca(sqlca);
if (con == NULL)
{
ecpg_raise(lineno, ECPG_NO_CONN, ECPG_SQLSTATE_CONNECTION_DOES_NOT_EXIST,
connection_name ? connection_name : ecpg_gettext("NULL"));
return false;
}
return true;
}
#ifdef ENABLE_THREAD_SAFETY
static void
ecpg_sqlca_key_destructor(void *arg)
{
free(arg); /* sqlca structure allocated in ECPGget_sqlca */
}
static void
ecpg_sqlca_key_init(void)
{
pthread_key_create(&sqlca_key, ecpg_sqlca_key_destructor);
}
#endif
struct sqlca_t *
ECPGget_sqlca(void)
{
#ifdef ENABLE_THREAD_SAFETY
struct sqlca_t *sqlca;
pthread_once(&sqlca_key_once, ecpg_sqlca_key_init);
sqlca = pthread_getspecific(sqlca_key);
if (sqlca == NULL)
{
sqlca = malloc(sizeof(struct sqlca_t));
if (sqlca == NULL)
return NULL;
ecpg_init_sqlca(sqlca);
pthread_setspecific(sqlca_key, sqlca);
}
return sqlca;
#else
return &sqlca;
#endif
}
bool
ECPGstatus(int lineno, const char *connection_name)
{
struct connection *con = ecpg_get_connection(connection_name);
if (!ecpg_init(con, connection_name, lineno))
return false;
/* are we connected? */
if (con->connection == NULL)
{
ecpg_raise(lineno, ECPG_NOT_CONN, ECPG_SQLSTATE_ECPG_INTERNAL_ERROR, con->name);
return false;
}
return true;
}
PGTransactionStatusType
ECPGtransactionStatus(const char *connection_name)
{
const struct connection *con;
con = ecpg_get_connection(connection_name);
if (con == NULL)
{
/* transaction status is unknown */
return PQTRANS_UNKNOWN;
}
return PQtransactionStatus(con->connection);
}
bool
ECPGtrans(int lineno, const char *connection_name, const char *transaction)
{
PGresult *res;
struct connection *con = ecpg_get_connection(connection_name);
if (!ecpg_init(con, connection_name, lineno))
return false;
ecpg_log("ECPGtrans on line %d: action \"%s\"; connection \"%s\"\n", lineno, transaction, con ? con->name : "null");
/* if we have no connection we just simulate the command */
if (con && con->connection)
{
/*
* If we got a transaction command but have no open transaction, we
* have to start one, unless we are in autocommit, where the
* developers have to take care themselves. However, if the command is
* a begin statement, we just execute it once. And if the command is
* commit or rollback prepared, we don't execute it.
*/
if (PQtransactionStatus(con->connection) == PQTRANS_IDLE &&
!con->autocommit &&
strncmp(transaction, "begin", 5) != 0 &&
strncmp(transaction, "start", 5) != 0 &&
strncmp(transaction, "commit prepared", 15) != 0 &&
strncmp(transaction, "rollback prepared", 17) != 0)
{
res = PQexec(con->connection, "begin transaction");
if (!ecpg_check_PQresult(res, lineno, con->connection, ECPG_COMPAT_PGSQL))
return false;
PQclear(res);
}
res = PQexec(con->connection, transaction);
if (!ecpg_check_PQresult(res, lineno, con->connection, ECPG_COMPAT_PGSQL))
return false;
PQclear(res);
}
return true;
}
void
ECPGdebug(int n, FILE *dbgs)
{
#ifdef ENABLE_THREAD_SAFETY
pthread_mutex_lock(&debug_init_mutex);
#endif
if (n > 100)
{
ecpg_internal_regression_mode = true;
simple_debug = n - 100;
}
else
simple_debug = n;
debugstream = dbgs;
ecpg_log("ECPGdebug: set to %d\n", simple_debug);
#ifdef ENABLE_THREAD_SAFETY
pthread_mutex_unlock(&debug_init_mutex);
#endif
}
void
ecpg_log(const char *format,...)
{
va_list ap;
struct sqlca_t *sqlca = ECPGget_sqlca();
const char *intl_format;
int bufsize;
char *fmt;
if (!simple_debug)
return;
/* localize the error message string */
intl_format = ecpg_gettext(format);
/*
* Insert PID into the format, unless ecpg_internal_regression_mode is set
* (regression tests want unchanging output).
*/
bufsize = strlen(intl_format) + 100;
fmt = (char *) malloc(bufsize);
if (fmt == NULL)
return;
if (ecpg_internal_regression_mode)
snprintf(fmt, bufsize, "[NO_PID]: %s", intl_format);
else
snprintf(fmt, bufsize, "[%d]: %s", (int) getpid(), intl_format);
#ifdef ENABLE_THREAD_SAFETY
pthread_mutex_lock(&debug_mutex);
#endif
va_start(ap, format);
vfprintf(debugstream, fmt, ap);
va_end(ap);
/* dump out internal sqlca variables */
if (ecpg_internal_regression_mode && sqlca != NULL)
{
fprintf(debugstream, "[NO_PID]: sqlca: code: %ld, state: %s\n",
sqlca->sqlcode, sqlca->sqlstate);
}
fflush(debugstream);
#ifdef ENABLE_THREAD_SAFETY
pthread_mutex_unlock(&debug_mutex);
#endif
free(fmt);
}
void
ECPGset_noind_null(enum ECPGttype type, void *ptr)
{
switch (type)
{
case ECPGt_char:
case ECPGt_unsigned_char:
case ECPGt_string:
*((char *) ptr) = '\0';
break;
case ECPGt_short:
case ECPGt_unsigned_short:
*((short int *) ptr) = SHRT_MIN;
break;
case ECPGt_int:
case ECPGt_unsigned_int:
*((int *) ptr) = INT_MIN;
break;
case ECPGt_long:
case ECPGt_unsigned_long:
case ECPGt_date:
*((long *) ptr) = LONG_MIN;
break;
case ECPGt_long_long:
case ECPGt_unsigned_long_long:
*((long long *) ptr) = LONG_LONG_MIN;
break;
case ECPGt_float:
memset((char *) ptr, 0xff, sizeof(float));
break;
case ECPGt_double:
memset((char *) ptr, 0xff, sizeof(double));
break;
case ECPGt_varchar:
*(((struct ECPGgeneric_varchar *) ptr)->arr) = 0x00;
((struct ECPGgeneric_varchar *) ptr)->len = 0;
break;
case ECPGt_bytea:
((struct ECPGgeneric_bytea *) ptr)->len = 0;
break;
case ECPGt_decimal:
memset((char *) ptr, 0, sizeof(decimal));
((decimal *) ptr)->sign = NUMERIC_NULL;
break;
case ECPGt_numeric:
memset((char *) ptr, 0, sizeof(numeric));
((numeric *) ptr)->sign = NUMERIC_NULL;
break;
case ECPGt_interval:
memset((char *) ptr, 0xff, sizeof(interval));
break;
case ECPGt_timestamp:
memset((char *) ptr, 0xff, sizeof(timestamp));
break;
default:
break;
}
}
static bool
_check(const unsigned char *ptr, int length)
{
for (length--; length >= 0; length--)
if (ptr[length] != 0xff)
return false;
return true;
}
bool
ECPGis_noind_null(enum ECPGttype type, const void *ptr)
{
switch (type)
{
case ECPGt_char:
case ECPGt_unsigned_char:
case ECPGt_string:
if (*((const char *) ptr) == '\0')
return true;
break;
case ECPGt_short:
case ECPGt_unsigned_short:
if (*((const short int *) ptr) == SHRT_MIN)
return true;
break;
case ECPGt_int:
case ECPGt_unsigned_int:
if (*((const int *) ptr) == INT_MIN)
return true;
break;
case ECPGt_long:
case ECPGt_unsigned_long:
case ECPGt_date:
if (*((const long *) ptr) == LONG_MIN)
return true;
break;
case ECPGt_long_long:
case ECPGt_unsigned_long_long:
if (*((const long long *) ptr) == LONG_LONG_MIN)
return true;
break;
case ECPGt_float:
return _check(ptr, sizeof(float));
break;
case ECPGt_double:
return _check(ptr, sizeof(double));
break;
case ECPGt_varchar:
if (*(((const struct ECPGgeneric_varchar *) ptr)->arr) == 0x00)
return true;
break;
case ECPGt_bytea:
if (((const struct ECPGgeneric_bytea *) ptr)->len == 0)
return true;
break;
case ECPGt_decimal:
if (((const decimal *) ptr)->sign == NUMERIC_NULL)
return true;
break;
case ECPGt_numeric:
if (((const numeric *) ptr)->sign == NUMERIC_NULL)
return true;
break;
case ECPGt_interval:
return _check(ptr, sizeof(interval));
break;
case ECPGt_timestamp:
return _check(ptr, sizeof(timestamp));
break;
default:
break;
}
return false;
}
#ifdef WIN32
#ifdef ENABLE_THREAD_SAFETY
void
win32_pthread_mutex(volatile pthread_mutex_t *mutex)
{
if (mutex->handle == NULL)
{
while (InterlockedExchange((LONG *) &mutex->initlock, 1) == 1)
Sleep(0);
if (mutex->handle == NULL)
mutex->handle = CreateMutex(NULL, FALSE, NULL);
InterlockedExchange((LONG *) &mutex->initlock, 0);
}
}
static pthread_mutex_t win32_pthread_once_lock = PTHREAD_MUTEX_INITIALIZER;
void
win32_pthread_once(volatile pthread_once_t *once, void (*fn) (void))
{
if (!*once)
{
pthread_mutex_lock(&win32_pthread_once_lock);
if (!*once)
{
fn();
*once = true;
}
pthread_mutex_unlock(&win32_pthread_once_lock);
}
}
#endif /* ENABLE_THREAD_SAFETY */
#endif /* WIN32 */
#ifdef ENABLE_NLS
char *
ecpg_gettext(const char *msgid)
{
static bool already_bound = false;
if (!already_bound)
{
/* dgettext() preserves errno, but bindtextdomain() doesn't */
#ifdef WIN32
int save_errno = GetLastError();
#else
int save_errno = errno;
#endif
const char *ldir;
already_bound = true;
/* No relocatable lookup here because the binary could be anywhere */
ldir = getenv("PGLOCALEDIR");
if (!ldir)
ldir = LOCALEDIR;
bindtextdomain(PG_TEXTDOMAIN("ecpglib"), ldir);
#ifdef WIN32
SetLastError(save_errno);
#else
errno = save_errno;
#endif
}
return dgettext(PG_TEXTDOMAIN("ecpglib"), msgid);
}
#endif /* ENABLE_NLS */
struct var_list *ivlist = NULL;
void
ECPGset_var(int number, void *pointer, int lineno)
{
struct var_list *ptr;
struct sqlca_t *sqlca = ECPGget_sqlca();
if (sqlca == NULL)
{
ecpg_raise(lineno, ECPG_OUT_OF_MEMORY,
ECPG_SQLSTATE_ECPG_OUT_OF_MEMORY, NULL);
return;
}
ecpg_init_sqlca(sqlca);
for (ptr = ivlist; ptr != NULL; ptr = ptr->next)
{
if (ptr->number == number)
{
/* already known => just change pointer value */
ptr->pointer = pointer;
return;
}
}
/* a new one has to be added */
ptr = (struct var_list *) calloc(1L, sizeof(struct var_list));
if (!ptr)
{
struct sqlca_t *sqlca = ECPGget_sqlca();
if (sqlca == NULL)
{
ecpg_raise(lineno, ECPG_OUT_OF_MEMORY,
ECPG_SQLSTATE_ECPG_OUT_OF_MEMORY, NULL);
return;
}
sqlca->sqlcode = ECPG_OUT_OF_MEMORY;
strncpy(sqlca->sqlstate, "YE001", sizeof(sqlca->sqlstate));
snprintf(sqlca->sqlerrm.sqlerrmc, sizeof(sqlca->sqlerrm.sqlerrmc), "out of memory on line %d", lineno);
sqlca->sqlerrm.sqlerrml = strlen(sqlca->sqlerrm.sqlerrmc);
/* free all memory we have allocated for the user */
ECPGfree_auto_mem();
}
else
{
ptr->number = number;
ptr->pointer = pointer;
ptr->next = ivlist;
ivlist = ptr;
}
}
void *
ECPGget_var(int number)
{
struct var_list *ptr;
for (ptr = ivlist; ptr != NULL && ptr->number != number; ptr = ptr->next);
return (ptr) ? ptr->pointer : NULL;
}