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mirror of https://github.com/postgres/postgres.git synced 2025-04-27 22:56:53 +03:00
Tom Lane 0028b55bc8 Clean up Windows-specific mutex code in libpq and ecpglib.
Fix pthread-win32.h and pthread-win32.c to provide a more complete
emulation of POSIX pthread mutexes: define PTHREAD_MUTEX_INITIALIZER
and make sure that pthread_mutex_lock() can operate on a mutex
object that's been initialized that way.  Then we don't need the
duplicative platform-specific logic in default_threadlock() and
pgtls_init(), which we'd otherwise need yet a third copy of for
an upcoming bug fix.

Also, since default_threadlock() supposes that pthread_mutex_lock()
cannot fail, try to ensure that that's actually true, by getting
rid of the malloc call that was formerly involved in initializing
an emulated mutex.  We can define an extra state for the spinlock
field instead.

Also, replace the similar code in ecpglib/misc.c with this version.
While ecpglib's version at least had a POSIX-compliant API, it
also had the potential of failing during mutex init (but here,
because of CreateMutex failure rather than malloc failure).  Since
all of misc.c's callers ignore failures, it seems like a wise idea
to avoid failures here too.

A further improvement in this area could be to unify libpq's and
ecpglib's implementations into a src/port/pthread-win32.c file.
But that doesn't seem like a bug fix, so I'll desist for now.

In preparation for the aforementioned bug fix, back-patch to all
supported branches.

Discussion: https://postgr.es/m/264860.1707163416@sss.pgh.pa.us
2024-02-09 11:11:39 -05:00

568 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'
}
};
static pthread_key_t sqlca_key;
static pthread_once_t sqlca_key_once = PTHREAD_ONCE_INIT;
static pthread_mutex_t debug_mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t debug_init_mutex = PTHREAD_MUTEX_INITIALIZER;
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;
}
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);
}
struct sqlca_t *
ECPGget_sqlca(void)
{
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;
}
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)
{
pthread_mutex_lock(&debug_init_mutex);
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);
pthread_mutex_unlock(&debug_init_mutex);
}
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);
pthread_mutex_lock(&debug_mutex);
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);
pthread_mutex_unlock(&debug_mutex);
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
int
pthread_mutex_init(pthread_mutex_t *mp, void *attr)
{
mp->initstate = 0;
return 0;
}
int
pthread_mutex_lock(pthread_mutex_t *mp)
{
/* Initialize the csection if not already done */
if (mp->initstate != 1)
{
LONG istate;
while ((istate = InterlockedExchange(&mp->initstate, 2)) == 2)
Sleep(0); /* wait, another thread is doing this */
if (istate != 1)
InitializeCriticalSection(&mp->csection);
InterlockedExchange(&mp->initstate, 1);
}
EnterCriticalSection(&mp->csection);
return 0;
}
int
pthread_mutex_unlock(pthread_mutex_t *mp)
{
if (mp->initstate != 1)
return EINVAL;
LeaveCriticalSection(&mp->csection);
return 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 /* WIN32 */
#ifdef ENABLE_NLS
char *
ecpg_gettext(const char *msgid)
{
/*
* If multiple threads come through here at about the same time, it's okay
* for more than one of them to call bindtextdomain(). But it's not okay
* for any of them to reach dgettext() before bindtextdomain() is
* complete, so don't set the flag till that's done. Use "volatile" just
* to be sure the compiler doesn't try to get cute.
*/
static volatile 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;
/* No relocatable lookup here because the binary could be anywhere */
ldir = getenv("PGLOCALEDIR");
if (!ldir)
ldir = LOCALEDIR;
bindtextdomain(PG_TEXTDOMAIN("ecpglib"), ldir);
already_bound = true;
#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)
{
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;
}