From 3e87ba6ef7ee381c46af6fa3871c366b947d87da Mon Sep 17 00:00:00 2001
From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: Thu, 18 Feb 2010 11:13:46 +0000
Subject: [PATCH] Fix pq_getbyte_if_available() function. It was confused on
what it returns if no data is immediately available. Patch by me with
numerous fixes from Fujii Masao and Magnus Hagander.
---
src/backend/libpq/be-secure.c | 8 +++--
src/backend/libpq/pqcomm.c | 33 +++++++++++++++++++--
src/backend/replication/walsender.c | 46 ++++++++---------------------
3 files changed, 49 insertions(+), 38 deletions(-)
diff --git a/src/backend/libpq/be-secure.c b/src/backend/libpq/be-secure.c
index ea6b16c13ba..94998999501 100644
--- a/src/backend/libpq/be-secure.c
+++ b/src/backend/libpq/be-secure.c
@@ -11,7 +11,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/libpq/be-secure.c,v 1.96 2010/01/15 09:19:02 heikki Exp $
+ * $PostgreSQL: pgsql/src/backend/libpq/be-secure.c,v 1.97 2010/02/18 11:13:45 heikki Exp $
*
* Since the server static private key ($DataDir/server.key)
* will normally be stored unencrypted so that the database
@@ -256,7 +256,11 @@ rloop:
case SSL_ERROR_WANT_READ:
case SSL_ERROR_WANT_WRITE:
if (port->noblock)
- return 0;
+ {
+ errno = EWOULDBLOCK;
+ n = -1;
+ break;
+ }
#ifdef WIN32
pgwin32_waitforsinglesocket(SSL_get_fd(port->ssl),
(err == SSL_ERROR_WANT_READ) ?
diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c
index 8f40c93d892..98b27f1f71a 100644
--- a/src/backend/libpq/pqcomm.c
+++ b/src/backend/libpq/pqcomm.c
@@ -30,7 +30,7 @@
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/backend/libpq/pqcomm.c,v 1.203 2010/02/16 19:26:02 mha Exp $
+ * $PostgreSQL: pgsql/src/backend/libpq/pqcomm.c,v 1.204 2010/02/18 11:13:45 heikki Exp $
*
*-------------------------------------------------------------------------
*/
@@ -821,8 +821,8 @@ pq_peekbyte(void)
* pq_getbyte_if_available - get a single byte from connection,
* if available
*
- * The received byte is stored in *c. Returns 1 if a byte was read, 0 if
- * if no data was available, or EOF.
+ * The received byte is stored in *c. Returns 1 if a byte was read,
+ * 0 if no data was available, or EOF if trouble.
* --------------------------------
*/
int
@@ -848,6 +848,33 @@ pq_getbyte_if_available(unsigned char *c)
PG_TRY();
{
r = secure_read(MyProcPort, c, 1);
+ if (r < 0)
+ {
+ /*
+ * Ok if no data available without blocking or interrupted
+ * (though EINTR really shouldn't happen with a non-blocking
+ * socket). Report other errors.
+ */
+ if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
+ r = 0;
+ else
+ {
+ /*
+ * Careful: an ereport() that tries to write to the client would
+ * cause recursion to here, leading to stack overflow and core
+ * dump! This message must go *only* to the postmaster log.
+ */
+ ereport(COMMERROR,
+ (errcode_for_socket_access(),
+ errmsg("could not receive data from client: %m")));
+ r = EOF;
+ }
+ }
+ else if (r == 0)
+ {
+ /* EOF detected */
+ r = EOF;
+ }
}
PG_CATCH();
{
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index eb9a5425a2e..bf533fff73d 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -30,7 +30,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/replication/walsender.c,v 1.6 2010/02/17 04:19:39 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/replication/walsender.c,v 1.7 2010/02/18 11:13:46 heikki Exp $
*
*-------------------------------------------------------------------------
*/
@@ -176,14 +176,7 @@ WalSndHandshake(void)
ProcessConfigFile(PGC_SIGHUP);
}
- if (firstchar == EOF)
- {
- /* standby disconnected */
- ereport(COMMERROR,
- (errcode(ERRCODE_PROTOCOL_VIOLATION),
- errmsg("unexpected EOF on standby connection")));
- }
- else
+ if (firstchar != EOF)
{
/*
* Read the message contents. This is expected to be done without
@@ -193,9 +186,7 @@ WalSndHandshake(void)
firstchar = EOF; /* suitable message already logged */
}
-
/* Handle the very limited subset of commands expected in this phase */
-
switch (firstchar)
{
case 'Q': /* Query message */
@@ -286,14 +277,16 @@ WalSndHandshake(void)
break;
}
- /* 'X' means that the standby is closing the connection */
case 'X':
+ /* standby is closing the connection */
proc_exit(0);
case EOF:
- ereport(ERROR,
+ /* standby disconnected unexpectedly */
+ ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("unexpected EOF on standby connection")));
+ proc_exit(0);
default:
ereport(FATAL,
@@ -315,36 +308,23 @@ CheckClosedConnection(void)
r = pq_getbyte_if_available(&firstchar);
if (r < 0)
{
- /* no data available */
- if (errno == EAGAIN || errno == EWOULDBLOCK)
- return;
-
- /*
- * Ok if interrupted, though it shouldn't really happen with
- * a non-blocking operation.
- */
- if (errno == EINTR)
- return;
-
+ /* unexpected error or EOF */
ereport(COMMERROR,
- (errcode_for_socket_access(),
- errmsg("could not receive data from client: %m")));
+ (errcode(ERRCODE_PROTOCOL_VIOLATION),
+ errmsg("unexpected EOF on standby connection")));
+ proc_exit(0);
}
if (r == 0)
{
- /* standby disconnected unexpectedly */
- ereport(ERROR,
- (errcode(ERRCODE_PROTOCOL_VIOLATION),
- errmsg("unexpected EOF on standby connection")));
+ /* no data available without blocking */
+ return;
}
/* Handle the very limited subset of commands expected in this phase */
switch (firstchar)
{
/*
- * 'X' means that the standby is closing down the socket. EOF means
- * unexpected loss of standby connection. Either way, perform normal
- * shutdown.
+ * 'X' means that the standby is closing down the socket.
*/
case 'X':
proc_exit(0);
--
GitLab