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Ensure we discard unread/unsent data when abandoning a connection attempt.

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There are assorted situations wherein PQconnectPoll() will abandon a
connection attempt and try again with different parameters (eg, SSL versus
not SSL).  However, the code forgot to discard any pending data in libpq's
I/O buffers when doing this.  In at least one case (server returns E
message during SSL negotiation), there is unread input data which bollixes
the next connection attempt.  I have not checked to see whether this is
possible in the other cases where we close the socket and retry, but it
seems like a matter of good defensive programming to add explicit
buffer-flushing code to all of them.

This is one of several issues exposed by Daniel Farina's report of
misbehavior after a server-side fork failure.

This has been wrong since forever, so back-patch to all supported branches.
This commit is contained in:
Tom Lane 2011-08-27 14:16:30 -04:00
parent 30c62561a8
commit c68561cbea
1 changed files with 15 additions and 0 deletions
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15
src/interfaces/libpq/fe-connect.c
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@ -1449,6 +1449,9 @@ keep_going: /* We will come back to here until there is
closesocket(conn->sock);
conn->sock = -1;
conn->status = CONNECTION_NEEDED;
/* Discard any unread/unsent data */
conn->inStart = conn->inCursor = conn->inEnd = 0;
conn->outCount = 0;
goto keep_going;
}
else
@ -1486,6 +1489,9 @@ keep_going: /* We will come back to here until there is
closesocket(conn->sock);
conn->sock = -1;
conn->status = CONNECTION_NEEDED;
/* Discard any unread/unsent data */
conn->inStart = conn->inCursor = conn->inEnd = 0;
conn->outCount = 0;
goto keep_going;
}
}
@ -1599,6 +1605,9 @@ keep_going: /* We will come back to here until there is
closesocket(conn->sock);
conn->sock = -1;
conn->status = CONNECTION_NEEDED;
/* Discard any unread/unsent data */
conn->inStart = conn->inCursor = conn->inEnd = 0;
conn->outCount = 0;
goto keep_going;
}
@ -1666,6 +1675,9 @@ keep_going: /* We will come back to here until there is
closesocket(conn->sock);
conn->sock = -1;
conn->status = CONNECTION_NEEDED;
/* Discard any unread/unsent data */
conn->inStart = conn->inCursor = conn->inEnd = 0;
conn->outCount = 0;
goto keep_going;
}
@ -1685,6 +1697,9 @@ keep_going: /* We will come back to here until there is
closesocket(conn->sock);
conn->sock = -1;
conn->status = CONNECTION_NEEDED;
/* Discard any unread/unsent data */
conn->inStart = conn->inCursor = conn->inEnd = 0;
conn->outCount = 0;
goto keep_going;
}
#endif