One restriction is that no two threads attempt to manipulate the same
PGconn object at the same time. In particular, you cannot
issue concurrent commands from different threads through the same
-connection object. (If you need to run concurrent commands, start up
+connection object. (If you need to run concurrent commands, use
multiple connections.)
safety It is better to use the md5 method,
which is thread-safe on all platforms.
+
+
libpq must ignore
SIGPIPE signals+generated internally by send() calls to backend processes.
+When
PostgreSQL is configured without+
--enable-thread-safety, libpq sets+SIGPIPE to SIG_IGN before each
+send() call and restores the original signal handler after
+completion. When --enable-thread-safety is used,
+
libpq installs its own SIGPIPE handler+before the first database connection if no custom SIGPIPE
+handler has been installed previously. This handler uses thread-local
+storage to determine if a SIGPIPE signal has been generated
+by an internal send(). If an application wants to install
+its own SIGPIPE signal handler, it should call
+PQinSend() to determine if it should ignore the
+SIGPIPE signal. This function is available in both
+thread-safe and non-thread-safe versions of
libpq.+
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/nodes/read.c,v 1.37 2004/01/07 21:12:56 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/nodes/read.c,v 1.38 2004/01/09 02:02:43 momjian Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
#include
#include
+#include "nodes/value.h"
#include "nodes/pg_list.h"
#include "nodes/readfuncs.h"
#include "nodes/value.h"
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/interfaces/libpq/fe-connect.c,v 1.266 2004/01/07 18:56:29 neilc Exp $
+ * $PostgreSQL: pgsql/src/interfaces/libpq/fe-connect.c,v 1.267 2004/01/09 02:02:43 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#endif
+#ifdef ENABLE_THREAD_SAFETY
+#endif
+
#include "libpq/ip.h"
#include "mb/pg_wchar.h"
#define DefaultSSLMode "disable"
#endif
-
/* ----------
* Definition of the conninfo parameters and their fallback resources.
*
static char *PasswordFromFile(char *hostname, char *port, char *dbname,
char *username);
+
/*
* Connecting to a Database
*
struct addrinfo hint;
const char *node = NULL;
int ret;
+#ifdef ENABLE_THREAD_SAFETY
+ static pthread_once_t check_sigpipe_once = PTHREAD_ONCE_INIT;
+
+ /* Check only on first connection request */
+ pthread_once(&check_sigpipe_once, check_sigpipe_handler);
+#endif
if (!conn)
return 0;
#undef LINELEN
}
+
* didn't really belong there.
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/interfaces/libpq/fe-print.c,v 1.49 2003/11/29 19:52:12 pgsql Exp $
+ * $PostgreSQL: pgsql/src/interfaces/libpq/fe-print.c,v 1.50 2004/01/09 02:02:43 momjian Exp $
*
*-------------------------------------------------------------------------
*/
int fs_len = strlen(po->fieldSep);
int total_line_length = 0;
int usePipe = 0;
- pqsigfunc oldsigpipehandler = NULL;
char *pagerenv;
+#if !defined(ENABLE_THREAD_SAFETY) && !defined(WIN32)
+ pqsigfunc oldsigpipehandler = NULL;
+#endif
#ifdef TIOCGWINSZ
struct winsize screen_size;
if (fout)
{
usePipe = 1;
+#ifdef ENABLE_THREAD_SAFETY
+ pthread_setspecific(thread_in_send, "t");
+#else
#ifndef WIN32
oldsigpipehandler = pqsignal(SIGPIPE, SIG_IGN);
+#endif
#endif
}
else
_pclose(fout);
#else
pclose(fout);
+#endif
+#ifdef ENABLE_THREAD_SAFETY
+ pthread_setspecific(thread_in_send, "f");
+#else
+#ifndef WIN32
pqsignal(SIGPIPE, oldsigpipehandler);
+#endif
#endif
}
if (po->html3 && !po->expanded)
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/interfaces/libpq/fe-secure.c,v 1.34 2003/12/18 22:49:26 tgl Exp $
+ * $PostgreSQL: pgsql/src/interfaces/libpq/fe-secure.c,v 1.35 2004/01/09 02:02:43 momjian Exp $
*
* NOTES
* The client *requires* a valid server certificate. Since
#endif
+#ifdef ENABLE_THREAD_SAFETY
+#endif
+
#ifndef HAVE_STRDUP
#include "strdup.h"
#endif
static SSL_CTX *SSL_context = NULL;
#endif
+#ifdef ENABLE_THREAD_SAFETY
+static void sigpipe_handler_ignore_send(int signo);
+pthread_key_t thread_in_send;
+#endif
+
/* ------------------------------------------------------------ */
/* Hardcoded values */
/* ------------------------------------------------------------ */
{
ssize_t n;
+#ifdef ENABLE_THREAD_SAFETY
+ pthread_setspecific(thread_in_send, "t");
+#else
#ifndef WIN32
pqsigfunc oldsighandler = pqsignal(SIGPIPE, SIG_IGN);
#endif
+#endif
#ifdef USE_SSL
if (conn->ssl)
#endif
n = send(conn->sock, ptr, len, 0);
+#ifdef ENABLE_THREAD_SAFETY
+ pthread_setspecific(thread_in_send, "f");
+#else
#ifndef WIN32
pqsignal(SIGPIPE, oldsighandler);
+#endif
#endif
return n;
}
#endif /* USE_SSL */
+
+
+#ifdef ENABLE_THREAD_SAFETY
+/*
+ * Check SIGPIPE handler and perhaps install our own.
+ */
+void
+check_sigpipe_handler(void)
+{
+ pqsigfunc pipehandler;
+
+ /*
+ * If the app hasn't set a SIGPIPE handler, define our own
+ * that ignores SIGPIPE on libpq send() and does SIG_DFL
+ * for other SIGPIPE cases.
+ */
+ pipehandler = pqsignalinquire(SIGPIPE);
+ if (pipehandler == SIG_DFL) /* not set by application */
+ {
+ /*
+ * Create key first because the signal handler might be called
+ * right after being installed.
+ */
+ pthread_key_create(&thread_in_send, NULL);
+ pqsignal(SIGPIPE, sigpipe_handler_ignore_send);
+ }
+}
+
+/*
+ * Threaded SIGPIPE signal handler
+ */
+void
+sigpipe_handler_ignore_send(int signo)
+{
+ /* If we have gotten a SIGPIPE outside send(), exit */
+ if (!PQinSend())
+ exit(128 + SIGPIPE); /* typical return value for SIG_DFL */
+}
+#endif
+
+/*
+ * Indicates whether the current thread is in send()
+ * For use by SIGPIPE signal handlers; they should
+ * ignore SIGPIPE when libpq is in send(). This means
+ * that the backend has died unexpectedly.
+ */
+pqbool
+PQinSend(void)
+{
+#ifdef ENABLE_THREAD_SAFETY
+ return (pthread_getspecific(thread_in_send) /* has it been set? */ &&
+ *(char *)pthread_getspecific(thread_in_send) == 't') ? true : false;
+#else
+ return false; /* No threading, so we can't be in send() */
+#endif
+}
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/interfaces/libpq/libpq-fe.h,v 1.101 2003/11/29 22:41:28 pgsql Exp $
+ * $PostgreSQL: pgsql/src/interfaces/libpq/libpq-fe.h,v 1.102 2004/01/09 02:02:43 momjian Exp $
*
*-------------------------------------------------------------------------
*/
/* Get encoding id from environment variable PGCLIENTENCODING */
extern int PQenv2encoding(void);
+/* === in fe-secure.c === */
+
+/*
+ * Indicates whether the libpq thread is in send().
+ * Used to ignore SIGPIPE if thread is in send().
+ */
+pqbool PQinSend(void);
+
#ifdef __cplusplus
}
#endif
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/interfaces/libpq/libpq-int.h,v 1.83 2003/11/29 22:41:28 pgsql Exp $
+ * $PostgreSQL: pgsql/src/interfaces/libpq/libpq-int.h,v 1.84 2004/01/09 02:02:43 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include
#endif
+#ifdef ENABLE_THREAD_SAFETY
+#endif
#if defined(WIN32) && (!defined(ssize_t))
typedef int ssize_t; /* ssize_t doesn't exist in VC (at least
extern void pqsecure_close(PGconn *);
extern ssize_t pqsecure_read(PGconn *, void *ptr, size_t len);
extern ssize_t pqsecure_write(PGconn *, const void *ptr, size_t len);
+#ifdef ENABLE_THREAD_SAFETY
+extern void check_sigpipe_handler(void);
+extern pthread_key_t thread_in_send;
+#endif
/*
* this is so that we can check if a connection is non-blocking internally
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/interfaces/libpq/pqsignal.c,v 1.18 2003/11/29 19:52:12 pgsql Exp $
+ * $PostgreSQL: pgsql/src/interfaces/libpq/pqsignal.c,v 1.19 2004/01/09 02:02:43 momjian Exp $
*
* NOTES
* This shouldn't be in libpq, but the monitor and some other
return oact.sa_handler;
#endif /* !HAVE_POSIX_SIGNALS */
}
+
+pqsigfunc
+pqsignalinquire(int signo)
+{
+#if !defined(HAVE_POSIX_SIGNALS)
+ pqsigfunc old_sigfunc;
+ int old_sigmask;
+
+ /* Prevent signal handler calls during test */
+ old_sigmask = sigblock(sigmask(signo));
+ old_sigfunc = signal(signo, SIG_DFL);
+ signal(signo, old_sigfunc);
+ sigblock(old_sigmask);
+ return old_sigfunc;
+#else
+ struct sigaction oact;
+
+ if (sigaction(signo, NULL, &oact) < 0)
+ return SIG_ERR;
+ return oact.sa_handler;
+#endif /* !HAVE_POSIX_SIGNALS */
+}
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/interfaces/libpq/pqsignal.h,v 1.16 2003/11/29 22:41:28 pgsql Exp $
+ * $PostgreSQL: pgsql/src/interfaces/libpq/pqsignal.h,v 1.17 2004/01/09 02:02:43 momjian Exp $
*
* NOTES
* This shouldn't be in libpq, but the monitor and some other
extern pqsigfunc pqsignal(int signo, pqsigfunc func);
+extern pqsigfunc pqsignalinquire(int signo);
+
#endif /* PQSIGNAL_H */
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