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-rw-r--r--src/interfaces/libpq/fe-cancel.c102
-rw-r--r--src/interfaces/libpq/fe-connect.c15
-rw-r--r--src/interfaces/libpq/fe-protocol3.c45
-rw-r--r--src/interfaces/libpq/libpq-int.h7
4 files changed, 138 insertions, 31 deletions
diff --git a/src/interfaces/libpq/fe-cancel.c b/src/interfaces/libpq/fe-cancel.c
index 7ebaa335bba..e84e64bf2a7 100644
--- a/src/interfaces/libpq/fe-cancel.c
+++ b/src/interfaces/libpq/fe-cancel.c
@@ -1,7 +1,7 @@
/*-------------------------------------------------------------------------
*
* fe-cancel.c
- * functions related to setting up a connection to the backend
+ * functions related to query cancellation
*
* Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
@@ -41,7 +41,6 @@ struct pg_cancel
{
SockAddr raddr; /* Remote address */
int be_pid; /* PID of to-be-canceled backend */
- int be_key; /* cancel key of to-be-canceled backend */
int pgtcp_user_timeout; /* tcp user timeout */
int keepalives; /* use TCP keepalives? */
int keepalives_idle; /* time between TCP keepalives */
@@ -49,6 +48,10 @@ struct pg_cancel
* retransmits */
int keepalives_count; /* maximum number of TCP keepalive
* retransmits */
+
+ /* Pre-constructed cancel request packet starts here */
+ int32 cancel_pkt_len; /* in network-byte-order */
+ char cancel_req[FLEXIBLE_ARRAY_MEMBER]; /* CancelRequestPacket */
};
@@ -83,6 +86,13 @@ PQcancelCreate(PGconn *conn)
return (PGcancelConn *) cancelConn;
}
+ /* Check that we have received a cancellation key */
+ if (conn->be_cancel_key_len == 0)
+ {
+ libpq_append_conn_error(cancelConn, "no cancellation key received");
+ return (PGcancelConn *) cancelConn;
+ }
+
/*
* Indicate that this connection is used to send a cancellation
*/
@@ -101,7 +111,15 @@ PQcancelCreate(PGconn *conn)
* Copy cancellation token data from the original connection
*/
cancelConn->be_pid = conn->be_pid;
- cancelConn->be_key = conn->be_key;
+ if (conn->be_cancel_key != NULL)
+ {
+ cancelConn->be_cancel_key = malloc(conn->be_cancel_key_len);
+ if (!conn->be_cancel_key)
+ goto oom_error;
+ memcpy(cancelConn->be_cancel_key, conn->be_cancel_key, conn->be_cancel_key_len);
+ }
+ cancelConn->be_cancel_key_len = conn->be_cancel_key_len;
+ cancelConn->pversion = conn->pversion;
/*
* Cancel requests should not iterate over all possible hosts. The request
@@ -349,6 +367,8 @@ PGcancel *
PQgetCancel(PGconn *conn)
{
PGcancel *cancel;
+ int cancel_req_len;
+ CancelRequestPacket *req;
if (!conn)
return NULL;
@@ -356,13 +376,17 @@ PQgetCancel(PGconn *conn)
if (conn->sock == PGINVALID_SOCKET)
return NULL;
- cancel = malloc(sizeof(PGcancel));
+ /* Check that we have received a cancellation key */
+ if (conn->be_cancel_key_len == 0)
+ return NULL;
+
+ cancel_req_len = offsetof(CancelRequestPacket, cancelAuthCode) + conn->be_cancel_key_len;
+ cancel = malloc(offsetof(PGcancel, cancel_req) + cancel_req_len);
if (cancel == NULL)
return NULL;
memcpy(&cancel->raddr, &conn->raddr, sizeof(SockAddr));
- cancel->be_pid = conn->be_pid;
- cancel->be_key = conn->be_key;
+
/* We use -1 to indicate an unset connection option */
cancel->pgtcp_user_timeout = -1;
cancel->keepalives = -1;
@@ -405,6 +429,13 @@ PQgetCancel(PGconn *conn)
goto fail;
}
+ req = (CancelRequestPacket *) &cancel->cancel_req;
+ req->cancelRequestCode = (MsgType) pg_hton32(CANCEL_REQUEST_CODE);
+ req->backendPID = pg_hton32(conn->be_pid);
+ memcpy(req->cancelAuthCode, conn->be_cancel_key, conn->be_cancel_key_len);
+ /* include the length field itself in the length */
+ cancel->cancel_pkt_len = pg_hton32(cancel_req_len + 4);
+
return cancel;
fail:
@@ -412,6 +443,42 @@ fail:
return NULL;
}
+/*
+ * PQsendCancelRequest
+ * Submit a CancelRequest message, but don't wait for it to finish
+ *
+ * Returns: 1 if successfully submitted
+ * 0 if error (conn->errorMessage is set)
+ */
+int
+PQsendCancelRequest(PGconn *cancelConn)
+{
+ CancelRequestPacket req;
+
+ /* Start the message. */
+ if (pqPutMsgStart(0, cancelConn))
+ return STATUS_ERROR;
+
+ /* Send the message body. */
+ memset(&req, 0, offsetof(CancelRequestPacket, cancelAuthCode));
+ req.cancelRequestCode = (MsgType) pg_hton32(CANCEL_REQUEST_CODE);
+ req.backendPID = pg_hton32(cancelConn->be_pid);
+ if (pqPutnchar((char *) &req, offsetof(CancelRequestPacket, cancelAuthCode), cancelConn))
+ return STATUS_ERROR;
+ if (pqPutnchar(cancelConn->be_cancel_key, cancelConn->be_cancel_key_len, cancelConn))
+ return STATUS_ERROR;
+
+ /* Finish the message. */
+ if (pqPutMsgEnd(cancelConn))
+ return STATUS_ERROR;
+
+ /* Flush to ensure backend gets it. */
+ if (pqFlush(cancelConn))
+ return STATUS_ERROR;
+
+ return STATUS_OK;
+}
+
/* PQfreeCancel: free a cancel structure */
void
PQfreeCancel(PGcancel *cancel)
@@ -465,11 +532,8 @@ PQcancel(PGcancel *cancel, char *errbuf, int errbufsize)
int save_errno = SOCK_ERRNO;
pgsocket tmpsock = PGINVALID_SOCKET;
int maxlen;
- struct
- {
- uint32 packetlen;
- CancelRequestPacket cp;
- } crp;
+ char recvbuf;
+ int cancel_pkt_len;
if (!cancel)
{
@@ -571,15 +635,15 @@ retry3:
goto cancel_errReturn;
}
- /* Create and send the cancel request packet. */
-
- crp.packetlen = pg_hton32((uint32) sizeof(crp));
- crp.cp.cancelRequestCode = (MsgType) pg_hton32(CANCEL_REQUEST_CODE);
- crp.cp.backendPID = pg_hton32(cancel->be_pid);
- crp.cp.cancelAuthCode = pg_hton32(cancel->be_key);
+ cancel_pkt_len = pg_ntoh32(cancel->cancel_pkt_len);
retry4:
- if (send(tmpsock, (char *) &crp, sizeof(crp), 0) != (int) sizeof(crp))
+
+ /*
+ * Send the cancel request packet. It starts with the message length at
+ * cancel_pkt_len, followed by the actual packet.
+ */
+ if (send(tmpsock, (char *) &cancel->cancel_pkt_len, cancel_pkt_len, 0) != cancel_pkt_len)
{
if (SOCK_ERRNO == EINTR)
/* Interrupted system call - we'll just try again */
@@ -596,7 +660,7 @@ retry4:
* read to obtain any data, we are just waiting for EOF to be signaled.
*/
retry5:
- if (recv(tmpsock, (char *) &crp, 1, 0) < 0)
+ if (recv(tmpsock, &recvbuf, 1, 0) < 0)
{
if (SOCK_ERRNO == EINTR)
/* Interrupted system call - we'll just try again */
diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index 5e3275ffd76..715b5d5aff4 100644
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -696,7 +696,12 @@ pqDropServerData(PGconn *conn)
if (!conn->cancelRequest)
{
conn->be_pid = 0;
- conn->be_key = 0;
+ if (conn->be_cancel_key != NULL)
+ {
+ free(conn->be_cancel_key);
+ conn->be_cancel_key = NULL;
+ }
+ conn->be_cancel_key_len = 0;
}
}
@@ -3692,13 +3697,7 @@ keep_going: /* We will come back to here until there is
*/
if (conn->cancelRequest)
{
- CancelRequestPacket cancelpacket;
-
- packetlen = sizeof(cancelpacket);
- cancelpacket.cancelRequestCode = (MsgType) pg_hton32(CANCEL_REQUEST_CODE);
- cancelpacket.backendPID = pg_hton32(conn->be_pid);
- cancelpacket.cancelAuthCode = pg_hton32(conn->be_key);
- if (pqPacketSend(conn, 0, &cancelpacket, packetlen) != STATUS_OK)
+ if (PQsendCancelRequest(conn) != STATUS_OK)
{
libpq_append_conn_error(conn, "could not send cancel packet: %s",
SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf)));
diff --git a/src/interfaces/libpq/fe-protocol3.c b/src/interfaces/libpq/fe-protocol3.c
index 7ba49ea4592..d85910f41fc 100644
--- a/src/interfaces/libpq/fe-protocol3.c
+++ b/src/interfaces/libpq/fe-protocol3.c
@@ -48,6 +48,7 @@ static int getRowDescriptions(PGconn *conn, int msgLength);
static int getParamDescriptions(PGconn *conn, int msgLength);
static int getAnotherTuple(PGconn *conn, int msgLength);
static int getParameterStatus(PGconn *conn);
+static int getBackendKeyData(PGconn *conn, int msgLength);
static int getNotify(PGconn *conn);
static int getCopyStart(PGconn *conn, ExecStatusType copytype);
static int getReadyForQuery(PGconn *conn);
@@ -308,9 +309,7 @@ pqParseInput3(PGconn *conn)
* just as easy to handle it as part of the main loop.
* Save the data and continue processing.
*/
- if (pqGetInt(&(conn->be_pid), 4, conn))
- return;
- if (pqGetInt(&(conn->be_key), 4, conn))
+ if (getBackendKeyData(conn, msgLength))
return;
break;
case PqMsg_RowDescription:
@@ -1524,6 +1523,46 @@ getParameterStatus(PGconn *conn)
return 0;
}
+/*
+ * parseInput subroutine to read a BackendKeyData message.
+ * Entry: 'v' message type and length have already been consumed.
+ * Exit: returns 0 if successfully consumed message.
+ * returns EOF if not enough data.
+ */
+static int
+getBackendKeyData(PGconn *conn, int msgLength)
+{
+ uint8 cancel_key_len;
+
+ if (conn->be_cancel_key)
+ {
+ free(conn->be_cancel_key);
+ conn->be_cancel_key = NULL;
+ conn->be_cancel_key_len = 0;
+ }
+
+ if (pqGetInt(&(conn->be_pid), 4, conn))
+ return EOF;
+
+ cancel_key_len = 5 + msgLength - (conn->inCursor - conn->inStart);
+
+ conn->be_cancel_key = malloc(cancel_key_len);
+ if (conn->be_cancel_key == NULL)
+ {
+ libpq_append_conn_error(conn, "out of memory");
+ /* discard the message */
+ return EOF;
+ }
+ if (pqGetnchar(conn->be_cancel_key, cancel_key_len, conn))
+ {
+ free(conn->be_cancel_key);
+ conn->be_cancel_key = NULL;
+ return EOF;
+ }
+ conn->be_cancel_key_len = cancel_key_len;
+ return 0;
+}
+
/*
* Attempt to read a Notify response message.
diff --git a/src/interfaces/libpq/libpq-int.h b/src/interfaces/libpq/libpq-int.h
index 232e0b00f75..25de3e95055 100644
--- a/src/interfaces/libpq/libpq-int.h
+++ b/src/interfaces/libpq/libpq-int.h
@@ -546,7 +546,8 @@ struct pg_conn
/* Miscellaneous stuff */
int be_pid; /* PID of backend --- needed for cancels */
- int be_key; /* key of backend --- needed for cancels */
+ char *be_cancel_key; /* query cancellation key and its length */
+ uint16 be_cancel_key_len;
pgParameterStatus *pstatus; /* ParameterStatus data */
int client_encoding; /* encoding id */
bool std_strings; /* standard_conforming_strings */
@@ -766,6 +767,10 @@ extern PGresult *pqFunctionCall3(PGconn *conn, Oid fnid,
int result_is_int,
const PQArgBlock *args, int nargs);
+/* === in fe-cancel.c === */
+
+extern int PQsendCancelRequest(PGconn *cancelConn);
+
/* === in fe-misc.c === */
/*
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-19 04:51:52 +0000