diff options
Diffstat (limited to 'src/interfaces/libpq/fe-cancel.c')
| -rw-r--r-- | src/interfaces/libpq/fe-cancel.c | 29 |
1 files changed, 28 insertions, 1 deletions
diff --git a/src/interfaces/libpq/fe-cancel.c b/src/interfaces/libpq/fe-cancel.c index cd3102346bf..c872a0267f0 100644 --- a/src/interfaces/libpq/fe-cancel.c +++ b/src/interfaces/libpq/fe-cancel.c @@ -137,6 +137,7 @@ PQcancelCreate(PGconn *conn) goto oom_error; originalHost = conn->connhost[conn->whichhost]; + cancelConn->connhost[0].type = originalHost.type; if (originalHost.host) { cancelConn->connhost[0].host = strdup(originalHost.host); @@ -378,7 +379,24 @@ PQgetCancel(PGconn *conn) /* Check that we have received a cancellation key */ if (conn->be_cancel_key_len == 0) - return NULL; + { + /* + * In case there is no cancel key, return an all-zero PGcancel object. + * Actually calling PQcancel on this will fail, but we allow creating + * the PGcancel object anyway. Arguably it would be better return NULL + * to indicate that cancellation is not possible, but there'd be no + * way for the caller to distinguish "out of memory" from "server did + * not send a cancel key". Also, this is how PGgetCancel() has always + * behaved, and if we changed it, some clients would stop working + * altogether with servers that don't support cancellation. (The + * modern PQcancelCreate() function returns a failed connection object + * instead.) + * + * The returned dummy object has cancel_pkt_len == 0; we check for + * that in PQcancel() to identify it as a dummy. + */ + return calloc(1, sizeof(PGcancel)); + } cancel_req_len = offsetof(CancelRequestPacket, cancelAuthCode) + conn->be_cancel_key_len; cancel = malloc(offsetof(PGcancel, cancel_req) + cancel_req_len); @@ -543,6 +561,15 @@ PQcancel(PGcancel *cancel, char *errbuf, int errbufsize) return false; } + if (cancel->cancel_pkt_len == 0) + { + /* This is a dummy PGcancel object, see PQgetCancel */ + strlcpy(errbuf, "PQcancel() -- no cancellation key received", errbufsize); + /* strlcpy probably doesn't change errno, but be paranoid */ + SOCK_ERRNO_SET(save_errno); + return false; + } + /* * We need to open a temporary connection to the postmaster. Do this with * only kernel calls. |