Fix pq_getbyte_if_available() function. It was confused on what it
authorHeikki Linnakangas <heikki.linnakangas@iki.fi>
Thu, 18 Feb 2010 11:13:46 +0000 (11:13 +0000)
committerHeikki Linnakangas <heikki.linnakangas@iki.fi>
Thu, 18 Feb 2010 11:13:46 +0000 (11:13 +0000)
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
src/backend/libpq/pqcomm.c
src/backend/replication/walsender.c

index ea6b16c13ba6dbf0ecb0a6fedcc94661d15d15d9..9499899950174fb9a02507ec4a1845684d97091b 100644 (file)
@@ -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) ?
index 8f40c93d89207ec8ba26ec28314da27bd3c9ebb9..98b27f1f71acf671e18c890b92d935b2b143afc8 100644 (file)
@@ -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();
    {
index eb9a5425a2ef00e21a47b57fc87aaf32e5ff0727..bf533fff73dd7238cbe59034281fa0b99a781dc5 100644 (file)
@@ -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);