*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.11 1996/10/07 07:18:34 scrappy Exp $
+ * $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.12 1996/10/12 07:48:49 bryanh Exp $
*
* NOTES
*
# endif
#endif
+#define LINGER_TIME 3
+ /* Max time in seconds for socket to linger (close() to block) waiting
+ for frontend to retrieve its message from us.
+ */
+
/*
* Info for garbage collection. Whenever a process dies, the Postmaster
* cleans up after it. Currently, NO information is required for cleanup,
static int MultiplexedBackends = 0;
static int MultiplexedBackendPort;
-#if defined(HBA)
-static int useHostBasedAuth = 1;
-#else
-static int useHostBasedAuth = 0;
-#endif
-
/*
* postmaster.c - function prototypes
*/
*/
status = PacketReceive(port, &port->buf, NON_BLOCKING);
switch (status) {
- case STATUS_OK:
- ConnStartup(port);
+ case STATUS_OK: {
+ int CSstatus; /* Completion status of ConnStartup */
+ char errormsg[200]; /* error msg from ConnStartup */
+
+ ConnStartup(port, &CSstatus, errormsg, sizeof(errormsg));
+
+ if (CSstatus == STATUS_ERROR)
+ send_error_reply(port, errormsg);
ActiveBackends = TRUE;
+ }
/*FALLTHROUGH*/
case STATUS_INVALID:
if (DebugLvl)
}
}
-static int
-ConnStartup(Port *port) /* receiving port */
+
+
+/*
+ ConnStartup: get the startup packet from the front end (client),
+ authenticate the user, and start up a backend.
+
+ If all goes well, return *status == STATUS_OK.
+ Otherwise, return *status == STATUS_ERROR and return a text string
+ explaining why in the "errormsg_len" bytes at "errormsg",
+*/
+
+static void
+ConnStartup(Port *port, int *status,
+ char *errormsg, const int errormsg_len)
{
- MsgType msgType;
- char namebuf[NAMEDATALEN + 1];
-/* StartupInfo *sp;*/
- int pid;
+ MsgType msgType;
+ char namebuf[NAMEDATALEN + 1];
+ int pid;
PacketBuf *p;
-/* sp = PacketBuf2StartupInfo(&port->buf);*/
StartupInfo sp;
char *tmp;
(void) strncpy(namebuf, sp.user, NAMEDATALEN);
namebuf[NAMEDATALEN] = '\0';
if (!namebuf[0]) {
- fprintf(stderr, "%s: ConnStartup: no user name specified\n",
- progname);
- return(STATUS_ERROR);
- }
-
- if (msgType == STARTUP_MSG && useHostBasedAuth)
- msgType = STARTUP_HBA_MSG;
- if (be_recvauth(msgType, port, namebuf,&sp) != STATUS_OK) {
- fprintf(stderr, "%s: ConnStartup: authentication failed\n",
- progname);
- return(STATUS_ERROR);
- }
-
- if (BackendStartup(&sp, port, &pid) != STATUS_OK) {
- fprintf(stderr, "%s: ConnStartup: couldn't start backend\n",
- progname);
- return(STATUS_ERROR);
+ snprintf(errormsg, errormsg_len,
+ "No Postgres username specified in startup packet.");
+ *status = STATUS_ERROR;
+ } else {
+ if (be_recvauth(msgType, port, namebuf, &sp) != STATUS_OK) {
+ snprintf(errormsg, errormsg_len,
+ "Failed to authenticate client as Postgres user '%s' "
+ "using authentication scheme %d.",
+ namebuf, msgType);
+ *status = STATUS_ERROR;
+ } else {
+ if (BackendStartup(&sp, port, &pid) != STATUS_OK) {
+ snprintf(errormsg, errormsg_len,
+ "Startup (fork) of backend failed.");
+ *status = STATUS_ERROR;
+ } else {
+ errormsg[0] = '\0'; /* just for robustness */
+ *status = STATUS_OK;
+ }
+ }
}
-
- return(STATUS_OK);
+ if (*status == STATUS_ERROR)
+ fprintf(stderr, "%s: ConnStartup: %s\n", progname, errormsg);
}
+
+/*
+ send_error_reply: send a reply to the front end telling it that
+ the connection was a bust, and why.
+
+ "port" tells to whom and how to send the reply. "errormsg" is
+ the string of text telling what the problem was.
+
+ It should be noted that we're executing a pretty messy protocol
+ here. The postmaster does not reply when the connection is
+ successful, but rather just hands the connection off to the
+ backend and the backend waits for a query from the frontend.
+ Thus, the frontend is not expecting any reply in regards to the
+ connect request.
+
+ But when the connection fails, we send this reply that starts
+ with "E". The frontend only gets this reply when it sends its
+ first query and waits for the reply. Nobody receives that query,
+ but this reply is already in the pipe, so that's what the
+ frontend sees.
+
+ Note that the backend closes the socket immediately after sending
+ the reply, so to give the frontend a fighting chance to see the
+ error info, we set the socket to linger up to 3 seconds waiting
+ for the frontend to retrieve the message. That's all the delay
+ we can afford, since we have other clients to serve and the
+ postmaster will be blocked the whole time. Also, if there is no
+ message space in the socket for the reply (shouldn't be a
+ problem) the postmaster will block until the frontend reads the
+ reply.
+
+*/
+
+static void
+send_error_reply(Port *port, const char *errormsg)
+{
+ int rc; /* return code from sendto */
+ char reply[201];
+ const struct linger linger_parm = {true, LINGER_TIME};
+ /* A parameter for setsockopt() that tells it to have close() block for
+ a while waiting for the frontend to read its outstanding messages.
+ */
+
+ snprintf(reply, sizeof(reply), "E%s", errormsg);
+
+ rc = send(port->sock, (Addr) reply, strlen(reply)+1, /* flags */ 0);
+ if (rc < 0)
+ fprintf(stderr,
+ "%s: ServerLoop:\t\t"
+ "Failed to send error reply to front end\n",
+ progname);
+ else if (rc < strlen(reply)+1)
+ fprintf(stderr,
+ "%s: ServerLoop:\t\t"
+ "Only partial error reply sent to front end.\n",
+ progname);
+
+ /* Now we have to make sure frontend has a chance to see what we
+ just wrote.
+ */
+ rc = setsockopt(port->sock, SOL_SOCKET, SO_LINGER,
+ &linger_parm, sizeof(linger_parm));
+}
+
+
/*
* ConnCreate -- create a local connection data structure
*/
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