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server.c
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server.c
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/*
* PgBouncer - Lightweight connection pooler for PostgreSQL.
*
* Copyright (c) 2007-2009 Marko Kreen, Skype Technologies OÜ
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* Handling of server connections
*/
#include "bouncer.h"
static bool load_parameter(PgSocket *server, PktHdr *pkt, bool startup)
{
const char *key, *val;
PgSocket *client = server->link;
/*
* Want to see complete packet. That means SMALL_PKT
* in sbuf.c must be larger than max param pkt.
*/
if (incomplete_pkt(pkt))
return false;
if (!mbuf_get_string(&pkt->data, &key))
goto failed;
if (!mbuf_get_string(&pkt->data, &val))
goto failed;
slog_debug(server, "S: param: %s = %s", key, val);
varcache_set(&server->vars, key, val);
if (client) {
slog_debug(client, "setting client var: %s='%s'", key, val);
varcache_set(&client->vars, key, val);
}
if (startup) {
if (!add_welcome_parameter(server->pool, key, val))
goto failed_store;
}
return true;
failed:
disconnect_server(server, true, "broken ParameterStatus packet");
return false;
failed_store:
disconnect_server(server, true, "failed to store ParameterStatus");
return false;
}
/* we cannot log in at all, notify clients */
void kill_pool_logins(PgPool *pool, const char *sqlstate, const char *msg)
{
struct List *item, *tmp;
PgSocket *client;
statlist_for_each_safe(item, &pool->waiting_client_list, tmp) {
client = container_of(item, PgSocket, head);
if (!client->wait_for_welcome)
continue;
disconnect_client_sqlstate(client, true, sqlstate, msg);
}
}
/* we cannot log in at all, notify clients with server error */
static void kill_pool_logins_server_error(PgPool *pool, PktHdr *errpkt)
{
const char *level, *msg, *sqlstate;
parse_server_error(errpkt, &level, &msg, &sqlstate);
log_warning("server login failed: %s %s", level, msg);
log_noise("kill_pool_logins_server_error: sqlstate: %s", sqlstate);
kill_pool_logins(pool, sqlstate, msg);
}
/* process packets on server auth phase */
static bool handle_server_startup(PgSocket *server, PktHdr *pkt)
{
SBuf *sbuf = &server->sbuf;
bool res = false;
const uint8_t *ckey;
if (incomplete_pkt(pkt)) {
disconnect_server(server, true, "partial pkt in login phase");
return false;
}
/* ignore most that happens during connect_query */
if (server->exec_on_connect) {
switch (pkt->type) {
case 'Z':
case 'S': /* handle them below */
break;
case 'E': /* log & ignore errors */
log_server_error("S: error while executing exec_on_query", pkt);
/* fallthrough */
default: /* ignore rest */
sbuf_prepare_skip(sbuf, pkt->len);
return true;
}
}
switch (pkt->type) {
default:
slog_error(server, "unknown pkt from server: '%c'", pkt_desc(pkt));
disconnect_server(server, true, "unknown pkt from server");
break;
case 'E': /* ErrorResponse */
if (!server->pool->welcome_msg_ready)
kill_pool_logins_server_error(server->pool, pkt);
else
log_server_error("S: login failed", pkt);
disconnect_server(server, true, "login failed");
break;
/* packets that need closer look */
case 'R': /* AuthenticationXXX */
slog_debug(server, "calling login_answer");
res = answer_authreq(server, pkt);
if (!res)
disconnect_server(server, false, "failed to answer authreq");
break;
case 'S': /* ParameterStatus */
res = load_parameter(server, pkt, true);
break;
case 'Z': /* ReadyForQuery */
if (server->exec_on_connect) {
server->exec_on_connect = false;
/* deliberately ignore transaction status */
} else if (server->pool->db->connect_query) {
server->exec_on_connect = true;
slog_debug(server, "server connect ok, send exec_on_connect");
SEND_generic(res, server, 'Q', "s", server->pool->db->connect_query);
if (!res)
disconnect_server(server, false, "exec_on_connect query failed");
break;
}
/* login ok */
slog_debug(server, "server login ok, start accepting queries");
server->ready = true;
/* got all params */
finish_welcome_msg(server);
/* need to notify sbuf if server was closed */
res = release_server(server);
/* let the takeover process handle it */
if (res && server->pool->db->admin)
res = takeover_login(server);
break;
/* ignorable packets */
case 'K': /* BackendKeyData */
if (!mbuf_get_bytes(&pkt->data, BACKENDKEY_LEN, &ckey)) {
disconnect_server(server, true, "bad cancel key");
return false;
}
memcpy(server->cancel_key, ckey, BACKENDKEY_LEN);
res = true;
break;
case 'N': /* NoticeResponse */
slog_noise(server, "skipping pkt: %c", pkt_desc(pkt));
res = true;
break;
}
if (res)
sbuf_prepare_skip(sbuf, pkt->len);
return res;
}
int pool_pool_mode(PgPool *pool)
{
int pool_mode = pool->user->pool_mode;
if (pool_mode == POOL_INHERIT)
pool_mode = pool->db->pool_mode;
if (pool_mode == POOL_INHERIT)
pool_mode = cf_pool_mode;
return pool_mode;
}
int pool_pool_size(PgPool *pool)
{
if (pool->db->pool_size < 0)
return cf_default_pool_size;
else
return pool->db->pool_size;
}
int pool_min_pool_size(PgPool *pool)
{
if (pool->db->min_pool_size < 0)
return cf_min_pool_size;
else
return pool->db->min_pool_size;
}
int pool_res_pool_size(PgPool *pool)
{
if (pool->db->res_pool_size < 0)
return cf_res_pool_size;
else
return pool->db->res_pool_size;
}
int database_max_connections(PgDatabase *db)
{
if (db->max_db_connections <= 0)
return cf_max_db_connections;
else
return db->max_db_connections;
}
int user_max_connections(PgUser *user)
{
if (user->max_user_connections <= 0)
return cf_max_user_connections;
else
return user->max_user_connections;
}
/* process packets on logged in connection */
static bool handle_server_work(PgSocket *server, PktHdr *pkt)
{
bool ready = false;
bool idle_tx = false;
char state;
SBuf *sbuf = &server->sbuf;
PgSocket *client = server->link;
bool async_response = false;
Assert(!server->pool->db->admin);
switch (pkt->type) {
default:
slog_error(server, "unknown pkt: '%c'", pkt_desc(pkt));
disconnect_server(server, true, "unknown pkt");
return false;
/* pooling decisions will be based on this packet */
case 'Z': /* ReadyForQuery */
/* if partial pkt, wait */
if (!mbuf_get_char(&pkt->data, &state))
return false;
/* set ready only if no tx */
if (state == 'I')
ready = true;
else if (pool_pool_mode(server->pool) == POOL_STMT) {
disconnect_server(server, true, "transaction blocks not allowed in statement pooling mode");
return false;
} else if (state == 'T' || state == 'E') {
idle_tx = true;
}
if (client && !server->setting_vars) {
if (client->expect_rfq_count > 0) {
client->expect_rfq_count--;
} else if (server->state == SV_ACTIVE) {
slog_debug(client, "unexpected ReadyForQuery - expect_rfq_count=%d", client->expect_rfq_count);
}
}
break;
case 'S': /* ParameterStatus */
if (!load_parameter(server, pkt, false))
return false;
break;
/*
* 'E' and 'N' packets currently set ->ready to false. Correct would
* be to leave ->ready as-is, because overall TX state stays same.
* It matters for connections in IDLE or USED state which get dirty
* suddenly but should not as they are still usable.
*
* But the 'E' or 'N' packet between transactions signifies probably
* dying backend. It is better to tag server as dirty and drop
* it later.
*/
case 'E': /* ErrorResponse */
if (server->setting_vars) {
/*
* the SET and user query will be different TX
* so we cannot report SET error to user.
*/
log_server_error("varcache_apply failed", pkt);
/*
* client probably gave invalid values in startup pkt.
*
* no reason to keep such guys.
*/
disconnect_server(server, true, "invalid server parameter");
return false;
}
/* fallthrough */
case 'C': /* CommandComplete */
/* ErrorResponse and CommandComplete show end of copy mode */
if (server->copy_mode) {
server->copy_mode = false;
/* it's impossible to track sync count over copy */
if (client)
client->expect_rfq_count = 0;
}
break;
case 'N': /* NoticeResponse */
break;
/* reply to LISTEN, don't change connection state */
case 'A': /* NotificationResponse */
idle_tx = server->idle_tx;
ready = server->ready;
async_response = true;
break;
/* copy mode */
case 'G': /* CopyInResponse */
case 'H': /* CopyOutResponse */
server->copy_mode = true;
break;
/* chat packets */
case '2': /* BindComplete */
case '3': /* CloseComplete */
case 'c': /* CopyDone(F/B) */
case 'f': /* CopyFail(F/B) */
case 'I': /* EmptyQueryResponse == CommandComplete */
case 'V': /* FunctionCallResponse */
case 'n': /* NoData */
case '1': /* ParseComplete */
case 's': /* PortalSuspended */
/* data packets, there will be more coming */
case 'd': /* CopyData(F/B) */
case 'D': /* DataRow */
case 't': /* ParameterDescription */
case 'T': /* RowDescription */
break;
}
server->idle_tx = idle_tx;
server->ready = ready;
server->pool->stats.server_bytes += pkt->len;
if (server->setting_vars) {
Assert(client);
sbuf_prepare_skip(sbuf, pkt->len);
} else if (client) {
if (client->state == CL_LOGIN) {
return handle_auth_query_response(client, pkt);
} else {
sbuf_prepare_send(sbuf, &client->sbuf, pkt->len);
/*
* Compute query and transaction times
*
* For pipelined overlapping commands, we wait until
* the last command is done (expect_rfq_count==0).
* That means, we count the time that PgBouncer is
* occupied in a query or transaction, not the total
* time that all queries/transactions take
* individually. For that, we would have to track the
* start time of each query separately in a queue or
* similar, not only per client.
*/
if (client->expect_rfq_count == 0) {
/* every statement (independent or in a transaction) counts as a query */
if (ready || idle_tx) {
if (client->query_start) {
usec_t total;
total = get_cached_time() - client->query_start;
client->query_start = 0;
server->pool->stats.query_time += total;
slog_debug(client, "query time: %d us", (int)total);
} else if (!async_response) {
slog_warning(client, "FIXME: query end, but query_start == 0");
}
}
/* statement ending in "idle" ends a transaction */
if (ready) {
if (client->xact_start) {
usec_t total;
total = get_cached_time() - client->xact_start;
client->xact_start = 0;
server->pool->stats.xact_time += total;
slog_debug(client, "transaction time: %d us", (int)total);
} else if (!async_response) {
/* XXX This happens during takeover if the new process
* continues a transaction. */
slog_warning(client, "FIXME: transaction end, but xact_start == 0");
}
}
}
}
} else {
if (server->state != SV_TESTED)
slog_warning(server,
"got packet '%c' from server when not linked",
pkt_desc(pkt));
sbuf_prepare_skip(sbuf, pkt->len);
}
return true;
}
/* got connection, decide what to do */
static bool handle_connect(PgSocket *server)
{
bool res = false;
PgPool *pool = server->pool;
char buf[PGADDR_BUF + 32];
bool is_unix = pga_is_unix(&server->remote_addr);
fill_local_addr(server, sbuf_socket(&server->sbuf), is_unix);
if (cf_log_connections) {
if (pga_is_unix(&server->remote_addr))
slog_info(server, "new connection to server");
else
slog_info(server, "new connection to server (from %s)",
pga_str(&server->local_addr, buf, sizeof(buf)));
}
/*
* If there are cancel requests waiting we first handle those. By handling
* these first we reduce the load on the server and we a server connection
* might actually become free to use for queries, because its query got
* canceled.
*
* Only if there are no cancel requests we proceed with the login procedure
* that's necessary to handle queries. Cancel requests need to be sent
* before the login procedure starts.
*
* A special case is when this is a peer pool, instead of a regular pool.
* Since only cancellation requests should be sent to peers.
*/
if (!statlist_empty(&pool->waiting_cancel_req_list)) {
slog_debug(server, "use it for pending cancel req");
if (forward_cancel_request(server)) {
change_server_state(server, SV_ACTIVE_CANCEL);
sbuf_continue(&server->sbuf);
} else {
/* notify disconnect_server() that connect did not fail */
server->ready = true;
disconnect_server(server, false, "failed to send cancel req");
}
} else if(pool->db->peer_id) {
/* notify disconnect_server() that connect did not fail */
server->ready = true;
disconnect_server(server, false, "peer server was not necessary anymore, because client cancel connection was already closed");
}else {
/* proceed with login */
if (server_connect_sslmode > SSLMODE_DISABLED && !is_unix) {
slog_noise(server, "P: SSL request");
res = send_sslreq_packet(server);
if (res)
server->wait_sslchar = true;
} else {
slog_noise(server, "P: startup");
res = send_startup_packet(server);
}
if (!res)
disconnect_server(server, false, "startup pkt failed");
}
return res;
}
static bool handle_sslchar(PgSocket *server, struct MBuf *data)
{
uint8_t schar = '?';
bool ok;
server->wait_sslchar = false;
ok = mbuf_get_byte(data, &schar);
if (!ok || (schar != 'S' && schar != 'N')) {
disconnect_server(server, false, "bad sslreq answer");
return false;
}
/*
* At this point we should have no data already buffered. If
* we do, it was received before we performed the SSL
* handshake, so it wasn't encrypted and indeed may have been
* injected by a man-in-the-middle.
*/
if (mbuf_avail_for_read(data) != 0) {
disconnect_server(server, false, "received unencrypted data after SSL response");
return false;
}
if (schar == 'S') {
slog_noise(server, "launching tls");
ok = sbuf_tls_connect(&server->sbuf, server->pool->db->host);
} else if (server_connect_sslmode >= SSLMODE_REQUIRE) {
disconnect_server(server, false, "server refused SSL");
return false;
} else {
/* proceed with non-TLS connection */
ok = send_startup_packet(server);
}
if (ok) {
sbuf_prepare_skip(&server->sbuf, 1);
} else {
disconnect_server(server, false, "sslreq processing failed");
}
return ok;
}
/* callback from SBuf */
bool server_proto(SBuf *sbuf, SBufEvent evtype, struct MBuf *data)
{
bool res = false;
PgSocket *server = container_of(sbuf, PgSocket, sbuf);
PgPool *pool = server->pool;
PktHdr pkt;
char infobuf[96];
Assert(is_server_socket(server));
Assert(server->state != SV_FREE);
/* may happen if close failed */
if (server->state == SV_JUSTFREE)
return false;
switch (evtype) {
case SBUF_EV_RECV_FAILED:
if (server->state == SV_ACTIVE_CANCEL)
disconnect_server(server, false, "successfully sent cancel request");
else
disconnect_server(server, false, "server conn crashed?");
break;
case SBUF_EV_SEND_FAILED:
disconnect_client(server->link, false, "unexpected eof");
break;
case SBUF_EV_READ:
if (server->wait_sslchar) {
res = handle_sslchar(server, data);
break;
}
if (incomplete_header(data)) {
slog_noise(server, "S: got partial header, trying to wait a bit");
break;
}
/* parse pkt header */
if (!get_header(data, &pkt)) {
disconnect_server(server, true, "bad pkt header");
break;
}
slog_noise(server, "read pkt='%c', len=%u", pkt_desc(&pkt), pkt.len);
server->request_time = get_cached_time();
switch (server->state) {
case SV_LOGIN:
res = handle_server_startup(server, &pkt);
break;
case SV_TESTED:
case SV_USED:
case SV_ACTIVE:
case SV_ACTIVE_CANCEL:
case SV_IDLE:
res = handle_server_work(server, &pkt);
break;
default:
fatal("server_proto: server in bad state: %d", server->state);
}
break;
case SBUF_EV_CONNECT_FAILED:
Assert(server->state == SV_LOGIN);
disconnect_server(server, false, "connect failed");
break;
case SBUF_EV_CONNECT_OK:
slog_debug(server, "S: connect ok");
Assert(server->state == SV_LOGIN);
server->request_time = get_cached_time();
res = handle_connect(server);
break;
case SBUF_EV_FLUSH:
res = true;
if (!server->ready)
break;
if (server->setting_vars) {
PgSocket *client = server->link;
Assert(client);
/*
* It's possible that the client vars and server vars have
* different string representations, but still Postgres did not
* send a ParamaterStatus packet. This happens when the server
* variable is the canonical version of the client variable, i.e.
* they mean the same just written slightly different. To make sure
* that the canonical version is also stored in the client, we now
* copy the server variables over to the client variables.
* See issue #776 for an example of this.
*/
varcache_set_canonical(server, client);
server->setting_vars = false;
sbuf_continue(&client->sbuf);
break;
}
if (pool_pool_mode(pool) != POOL_SESSION || server->state == SV_TESTED || server->resetting) {
server->resetting = false;
switch (server->state) {
case SV_ACTIVE:
case SV_ACTIVE_CANCEL:
case SV_TESTED:
/* keep link if client expects more Syncs */
if (server->link) {
if (server->link->expect_rfq_count > 0)
break;
}
/* retval does not matter here */
release_server(server);
break;
default:
slog_warning(server, "EV_FLUSH with state=%d", server->state);
case SV_IDLE:
break;
}
}
break;
case SBUF_EV_PKT_CALLBACK:
slog_warning(server, "SBUF_EV_PKT_CALLBACK with state=%d", server->state);
break;
case SBUF_EV_TLS_READY:
Assert(server->state == SV_LOGIN);
tls_get_connection_info(server->sbuf.tls, infobuf, sizeof infobuf);
if (cf_log_connections) {
slog_info(server, "SSL established: %s", infobuf);
} else {
slog_noise(server, "SSL established: %s", infobuf);
}
server->request_time = get_cached_time();
res = send_startup_packet(server);
if (res)
sbuf_continue(&server->sbuf);
else
disconnect_server(server, false, "TLS startup failed");
break;
}
if (!res && pool->db->admin)
takeover_login_failed();
return res;
}