in libs/curl/lib/multi.c [1886:2708]
static CURLMcode multi_runsingle(struct Curl_multi *multi,
struct curltime *nowp,
struct Curl_easy *data)
{
struct Curl_message *msg = NULL;
bool connected;
bool async;
bool protocol_connected = FALSE;
bool dophase_done = FALSE;
CURLMcode rc;
CURLcode result = CURLE_OK;
timediff_t recv_timeout_ms;
timediff_t send_timeout_ms;
int control;
if(!GOOD_EASY_HANDLE(data))
return CURLM_BAD_EASY_HANDLE;
if(multi->dead) {
/* a multi-level callback returned error before, meaning every individual
transfer now has failed */
result = CURLE_ABORTED_BY_CALLBACK;
multi_posttransfer(data);
multi_done(data, result, FALSE);
multistate(data, MSTATE_COMPLETED);
}
multi_warn_debug(multi, data);
do {
/* A "stream" here is a logical stream if the protocol can handle that
(HTTP/2), or the full connection for older protocols */
bool stream_error = FALSE;
rc = CURLM_OK;
if(multi_ischanged(multi, TRUE)) {
DEBUGF(infof(data, "multi changed, check CONNECT_PEND queue"));
process_pending_handles(multi); /* multiplexed */
}
if(data->mstate > MSTATE_CONNECT &&
data->mstate < MSTATE_COMPLETED) {
/* Make sure we set the connection's current owner */
DEBUGASSERT(data->conn);
if(!data->conn)
return CURLM_INTERNAL_ERROR;
}
/* Wait for the connect state as only then is the start time stored, but
we must not check already completed handles */
if((data->mstate >= MSTATE_CONNECT) && (data->mstate < MSTATE_COMPLETED) &&
multi_handle_timeout(data, nowp, &stream_error, &result, FALSE))
/* Skip the statemachine and go directly to error handling section. */
goto statemachine_end;
switch(data->mstate) {
case MSTATE_INIT:
/* Transitional state. init this transfer. A handle never comes
back to this state. */
result = Curl_pretransfer(data);
if(result)
break;
/* after init, go SETUP */
multistate(data, MSTATE_SETUP);
(void)Curl_pgrsTime(data, TIMER_STARTOP);
FALLTHROUGH();
case MSTATE_SETUP:
/* Transitional state. Setup things for a new transfer. The handle
can come back to this state on a redirect. */
*nowp = Curl_pgrsTime(data, TIMER_STARTSINGLE);
if(data->set.timeout)
Curl_expire(data, data->set.timeout, EXPIRE_TIMEOUT);
if(data->set.connecttimeout)
/* Since a connection might go to pending and back to CONNECT several
times before it actually takes off, we need to set the timeout once
in SETUP before we enter CONNECT the first time. */
Curl_expire(data, data->set.connecttimeout, EXPIRE_CONNECTTIMEOUT);
multistate(data, MSTATE_CONNECT);
FALLTHROUGH();
case MSTATE_CONNECT:
/* Connect. We want to get a connection identifier filled in. This state
can be entered from SETUP and from PENDING. */
result = Curl_connect(data, &async, &connected);
if(CURLE_NO_CONNECTION_AVAILABLE == result) {
/* There was no connection available. We will go to the pending
state and wait for an available connection. */
multistate(data, MSTATE_PENDING);
/* add this handle to the list of connect-pending handles */
Curl_llist_append(&multi->pending, data, &data->connect_queue);
/* unlink from the main list */
unlink_easy(multi, data);
result = CURLE_OK;
break;
}
else
process_pending_handles(data->multi);
if(!result) {
*nowp = Curl_pgrsTime(data, TIMER_POSTQUEUE);
if(async)
/* We are now waiting for an asynchronous name lookup */
multistate(data, MSTATE_RESOLVING);
else {
/* after the connect has been sent off, go WAITCONNECT unless the
protocol connect is already done and we can go directly to
WAITDO or DO! */
rc = CURLM_CALL_MULTI_PERFORM;
if(connected)
multistate(data, MSTATE_PROTOCONNECT);
else {
multistate(data, MSTATE_CONNECTING);
}
}
}
break;
case MSTATE_RESOLVING:
/* awaiting an asynch name resolve to complete */
{
struct Curl_dns_entry *dns = NULL;
struct connectdata *conn = data->conn;
const char *hostname;
DEBUGASSERT(conn);
#ifndef CURL_DISABLE_PROXY
if(conn->bits.httpproxy)
hostname = conn->http_proxy.host.name;
else
#endif
if(conn->bits.conn_to_host)
hostname = conn->conn_to_host.name;
else
hostname = conn->host.name;
/* check if we have the name resolved by now */
dns = Curl_fetch_addr(data, hostname, conn->primary.remote_port);
if(dns) {
#ifdef CURLRES_ASYNCH
data->state.async.dns = dns;
data->state.async.done = TRUE;
#endif
result = CURLE_OK;
infof(data, "Hostname '%s' was found in DNS cache", hostname);
}
if(!dns)
result = Curl_resolv_check(data, &dns);
/* Update sockets here, because the socket(s) may have been
closed and the application thus needs to be told, even if it
is likely that the same socket(s) will again be used further
down. If the name has not yet been resolved, it is likely
that new sockets have been opened in an attempt to contact
another resolver. */
rc = singlesocket(multi, data);
if(rc)
return rc;
if(dns) {
/* Perform the next step in the connection phase, and then move on
to the WAITCONNECT state */
result = Curl_once_resolved(data, &connected);
if(result)
/* if Curl_once_resolved() returns failure, the connection struct
is already freed and gone */
data->conn = NULL; /* no more connection */
else {
/* call again please so that we get the next socket setup */
rc = CURLM_CALL_MULTI_PERFORM;
if(connected)
multistate(data, MSTATE_PROTOCONNECT);
else {
multistate(data, MSTATE_CONNECTING);
}
}
}
if(result) {
/* failure detected */
stream_error = TRUE;
break;
}
}
break;
#ifndef CURL_DISABLE_HTTP
case MSTATE_TUNNELING:
/* this is HTTP-specific, but sending CONNECT to a proxy is HTTP... */
DEBUGASSERT(data->conn);
result = Curl_http_connect(data, &protocol_connected);
#ifndef CURL_DISABLE_PROXY
if(data->conn->bits.proxy_connect_closed) {
rc = CURLM_CALL_MULTI_PERFORM;
/* connect back to proxy again */
result = CURLE_OK;
multi_done(data, CURLE_OK, FALSE);
multistate(data, MSTATE_CONNECT);
}
else
#endif
if(!result) {
rc = CURLM_CALL_MULTI_PERFORM;
/* initiate protocol connect phase */
multistate(data, MSTATE_PROTOCONNECT);
}
else
stream_error = TRUE;
break;
#endif
case MSTATE_CONNECTING:
/* awaiting a completion of an asynch TCP connect */
DEBUGASSERT(data->conn);
result = Curl_conn_connect(data, FIRSTSOCKET, FALSE, &connected);
if(connected && !result) {
rc = CURLM_CALL_MULTI_PERFORM;
multistate(data, MSTATE_PROTOCONNECT);
}
else if(result) {
/* failure detected */
multi_posttransfer(data);
multi_done(data, result, TRUE);
stream_error = TRUE;
break;
}
break;
case MSTATE_PROTOCONNECT:
if(!result && data->conn->bits.reuse) {
/* ftp seems to hang when protoconnect on reused connection
* since we handle PROTOCONNECT in general inside the filers, it
* seems wrong to restart this on a reused connection. */
multistate(data, MSTATE_DO);
rc = CURLM_CALL_MULTI_PERFORM;
break;
}
if(!result)
result = protocol_connect(data, &protocol_connected);
if(!result && !protocol_connected) {
/* switch to waiting state */
multistate(data, MSTATE_PROTOCONNECTING);
rc = CURLM_CALL_MULTI_PERFORM;
}
else if(!result) {
/* protocol connect has completed, go WAITDO or DO */
multistate(data, MSTATE_DO);
rc = CURLM_CALL_MULTI_PERFORM;
}
else {
/* failure detected */
multi_posttransfer(data);
multi_done(data, result, TRUE);
stream_error = TRUE;
}
break;
case MSTATE_PROTOCONNECTING:
/* protocol-specific connect phase */
result = protocol_connecting(data, &protocol_connected);
if(!result && protocol_connected) {
/* after the connect has completed, go WAITDO or DO */
multistate(data, MSTATE_DO);
rc = CURLM_CALL_MULTI_PERFORM;
}
else if(result) {
/* failure detected */
multi_posttransfer(data);
multi_done(data, result, TRUE);
stream_error = TRUE;
}
break;
case MSTATE_DO:
if(data->set.fprereq) {
int prereq_rc;
/* call the prerequest callback function */
Curl_set_in_callback(data, true);
prereq_rc = data->set.fprereq(data->set.prereq_userp,
data->info.primary.remote_ip,
data->info.primary.local_ip,
data->info.primary.remote_port,
data->info.primary.local_port);
Curl_set_in_callback(data, false);
if(prereq_rc != CURL_PREREQFUNC_OK) {
failf(data, "operation aborted by pre-request callback");
/* failure in pre-request callback - do not do any other
processing */
result = CURLE_ABORTED_BY_CALLBACK;
multi_posttransfer(data);
multi_done(data, result, FALSE);
stream_error = TRUE;
break;
}
}
if(data->set.connect_only == 1) {
/* keep connection open for application to use the socket */
connkeep(data->conn, "CONNECT_ONLY");
multistate(data, MSTATE_DONE);
result = CURLE_OK;
rc = CURLM_CALL_MULTI_PERFORM;
}
else {
/* Perform the protocol's DO action */
result = multi_do(data, &dophase_done);
/* When multi_do() returns failure, data->conn might be NULL! */
if(!result) {
if(!dophase_done) {
#ifndef CURL_DISABLE_FTP
/* some steps needed for wildcard matching */
if(data->state.wildcardmatch) {
struct WildcardData *wc = data->wildcard;
if(wc->state == CURLWC_DONE || wc->state == CURLWC_SKIP) {
/* skip some states if it is important */
multi_done(data, CURLE_OK, FALSE);
/* if there is no connection left, skip the DONE state */
multistate(data, data->conn ?
MSTATE_DONE : MSTATE_COMPLETED);
rc = CURLM_CALL_MULTI_PERFORM;
break;
}
}
#endif
/* DO was not completed in one function call, we must continue
DOING... */
multistate(data, MSTATE_DOING);
rc = CURLM_CALL_MULTI_PERFORM;
}
/* after DO, go DO_DONE... or DO_MORE */
else if(data->conn->bits.do_more) {
/* we are supposed to do more, but we need to sit down, relax
and wait a little while first */
multistate(data, MSTATE_DOING_MORE);
rc = CURLM_CALL_MULTI_PERFORM;
}
else {
/* we are done with the DO, now DID */
multistate(data, MSTATE_DID);
rc = CURLM_CALL_MULTI_PERFORM;
}
}
else if((CURLE_SEND_ERROR == result) &&
data->conn->bits.reuse) {
/*
* In this situation, a connection that we were trying to use
* may have unexpectedly died. If possible, send the connection
* back to the CONNECT phase so we can try again.
*/
char *newurl = NULL;
followtype follow = FOLLOW_NONE;
CURLcode drc;
drc = Curl_retry_request(data, &newurl);
if(drc) {
/* a failure here pretty much implies an out of memory */
result = drc;
stream_error = TRUE;
}
multi_posttransfer(data);
drc = multi_done(data, result, FALSE);
/* When set to retry the connection, we must go back to the CONNECT
* state */
if(newurl) {
if(!drc || (drc == CURLE_SEND_ERROR)) {
follow = FOLLOW_RETRY;
drc = Curl_follow(data, newurl, follow);
if(!drc) {
multistate(data, MSTATE_SETUP);
rc = CURLM_CALL_MULTI_PERFORM;
result = CURLE_OK;
}
else {
/* Follow failed */
result = drc;
}
}
else {
/* done did not return OK or SEND_ERROR */
result = drc;
}
}
else {
/* Have error handler disconnect conn if we cannot retry */
stream_error = TRUE;
}
free(newurl);
}
else {
/* failure detected */
multi_posttransfer(data);
if(data->conn)
multi_done(data, result, FALSE);
stream_error = TRUE;
}
}
break;
case MSTATE_DOING:
/* we continue DOING until the DO phase is complete */
DEBUGASSERT(data->conn);
result = protocol_doing(data, &dophase_done);
if(!result) {
if(dophase_done) {
/* after DO, go DO_DONE or DO_MORE */
multistate(data, data->conn->bits.do_more?
MSTATE_DOING_MORE : MSTATE_DID);
rc = CURLM_CALL_MULTI_PERFORM;
} /* dophase_done */
}
else {
/* failure detected */
multi_posttransfer(data);
multi_done(data, result, FALSE);
stream_error = TRUE;
}
break;
case MSTATE_DOING_MORE:
/*
* When we are connected, DOING MORE and then go DID
*/
DEBUGASSERT(data->conn);
result = multi_do_more(data, &control);
if(!result) {
if(control) {
/* if positive, advance to DO_DONE
if negative, go back to DOING */
multistate(data, control == 1?
MSTATE_DID : MSTATE_DOING);
rc = CURLM_CALL_MULTI_PERFORM;
}
/* else
stay in DO_MORE */
}
else {
/* failure detected */
multi_posttransfer(data);
multi_done(data, result, FALSE);
stream_error = TRUE;
}
break;
case MSTATE_DID:
DEBUGASSERT(data->conn);
if(data->conn->bits.multiplex)
/* Check if we can move pending requests to send pipe */
process_pending_handles(multi); /* multiplexed */
/* Only perform the transfer if there is a good socket to work with.
Having both BAD is a signal to skip immediately to DONE */
if((data->conn->sockfd != CURL_SOCKET_BAD) ||
(data->conn->writesockfd != CURL_SOCKET_BAD))
multistate(data, MSTATE_PERFORMING);
else {
#ifndef CURL_DISABLE_FTP
if(data->state.wildcardmatch &&
((data->conn->handler->flags & PROTOPT_WILDCARD) == 0)) {
data->wildcard->state = CURLWC_DONE;
}
#endif
multistate(data, MSTATE_DONE);
}
rc = CURLM_CALL_MULTI_PERFORM;
break;
case MSTATE_RATELIMITING: /* limit-rate exceeded in either direction */
DEBUGASSERT(data->conn);
/* if both rates are within spec, resume transfer */
if(Curl_pgrsUpdate(data))
result = CURLE_ABORTED_BY_CALLBACK;
else
result = Curl_speedcheck(data, *nowp);
if(result) {
if(!(data->conn->handler->flags & PROTOPT_DUAL) &&
result != CURLE_HTTP2_STREAM)
streamclose(data->conn, "Transfer returned error");
multi_posttransfer(data);
multi_done(data, result, TRUE);
}
else {
send_timeout_ms = 0;
if(data->set.max_send_speed)
send_timeout_ms =
Curl_pgrsLimitWaitTime(data->progress.uploaded,
data->progress.ul_limit_size,
data->set.max_send_speed,
data->progress.ul_limit_start,
*nowp);
recv_timeout_ms = 0;
if(data->set.max_recv_speed)
recv_timeout_ms =
Curl_pgrsLimitWaitTime(data->progress.downloaded,
data->progress.dl_limit_size,
data->set.max_recv_speed,
data->progress.dl_limit_start,
*nowp);
if(!send_timeout_ms && !recv_timeout_ms) {
multistate(data, MSTATE_PERFORMING);
Curl_ratelimit(data, *nowp);
}
else if(send_timeout_ms >= recv_timeout_ms)
Curl_expire(data, send_timeout_ms, EXPIRE_TOOFAST);
else
Curl_expire(data, recv_timeout_ms, EXPIRE_TOOFAST);
}
break;
case MSTATE_PERFORMING:
{
char *newurl = NULL;
bool retry = FALSE;
/* check if over send speed */
send_timeout_ms = 0;
if(data->set.max_send_speed)
send_timeout_ms = Curl_pgrsLimitWaitTime(data->progress.uploaded,
data->progress.ul_limit_size,
data->set.max_send_speed,
data->progress.ul_limit_start,
*nowp);
/* check if over recv speed */
recv_timeout_ms = 0;
if(data->set.max_recv_speed)
recv_timeout_ms = Curl_pgrsLimitWaitTime(data->progress.downloaded,
data->progress.dl_limit_size,
data->set.max_recv_speed,
data->progress.dl_limit_start,
*nowp);
if(send_timeout_ms || recv_timeout_ms) {
Curl_ratelimit(data, *nowp);
multistate(data, MSTATE_RATELIMITING);
if(send_timeout_ms >= recv_timeout_ms)
Curl_expire(data, send_timeout_ms, EXPIRE_TOOFAST);
else
Curl_expire(data, recv_timeout_ms, EXPIRE_TOOFAST);
break;
}
/* read/write data if it is ready to do so */
result = Curl_readwrite(data);
if(data->req.done || (result == CURLE_RECV_ERROR)) {
/* If CURLE_RECV_ERROR happens early enough, we assume it was a race
* condition and the server closed the reused connection exactly when
* we wanted to use it, so figure out if that is indeed the case.
*/
CURLcode ret = Curl_retry_request(data, &newurl);
if(!ret)
retry = (newurl)?TRUE:FALSE;
else if(!result)
result = ret;
if(retry) {
/* if we are to retry, set the result to OK and consider the
request as done */
result = CURLE_OK;
data->req.done = TRUE;
}
}
else if((CURLE_HTTP2_STREAM == result) &&
Curl_h2_http_1_1_error(data)) {
CURLcode ret = Curl_retry_request(data, &newurl);
if(!ret) {
infof(data, "Downgrades to HTTP/1.1");
streamclose(data->conn, "Disconnect HTTP/2 for HTTP/1");
data->state.httpwant = CURL_HTTP_VERSION_1_1;
/* clear the error message bit too as we ignore the one we got */
data->state.errorbuf = FALSE;
if(!newurl)
/* typically for HTTP_1_1_REQUIRED error on first flight */
newurl = strdup(data->state.url);
/* if we are to retry, set the result to OK and consider the request
as done */
retry = TRUE;
result = CURLE_OK;
data->req.done = TRUE;
}
else
result = ret;
}
if(result) {
/*
* The transfer phase returned error, we mark the connection to get
* closed to prevent being reused. This is because we cannot possibly
* know if the connection is in a good shape or not now. Unless it is
* a protocol which uses two "channels" like FTP, as then the error
* happened in the data connection.
*/
if(!(data->conn->handler->flags & PROTOPT_DUAL) &&
result != CURLE_HTTP2_STREAM)
streamclose(data->conn, "Transfer returned error");
multi_posttransfer(data);
multi_done(data, result, TRUE);
}
else if(data->req.done && !Curl_cwriter_is_paused(data)) {
/* call this even if the readwrite function returned error */
multi_posttransfer(data);
/* When we follow redirects or is set to retry the connection, we must
to go back to the CONNECT state */
if(data->req.newurl || retry) {
followtype follow = FOLLOW_NONE;
if(!retry) {
/* if the URL is a follow-location and not just a retried request
then figure out the URL here */
free(newurl);
newurl = data->req.newurl;
data->req.newurl = NULL;
follow = FOLLOW_REDIR;
}
else
follow = FOLLOW_RETRY;
(void)multi_done(data, CURLE_OK, FALSE);
/* multi_done() might return CURLE_GOT_NOTHING */
result = Curl_follow(data, newurl, follow);
if(!result) {
multistate(data, MSTATE_SETUP);
rc = CURLM_CALL_MULTI_PERFORM;
}
}
else {
/* after the transfer is done, go DONE */
/* but first check to see if we got a location info even though we
are not following redirects */
if(data->req.location) {
free(newurl);
newurl = data->req.location;
data->req.location = NULL;
result = Curl_follow(data, newurl, FOLLOW_FAKE);
if(result) {
stream_error = TRUE;
result = multi_done(data, result, TRUE);
}
}
if(!result) {
multistate(data, MSTATE_DONE);
rc = CURLM_CALL_MULTI_PERFORM;
}
}
}
else if(data->state.select_bits && !Curl_xfer_is_blocked(data)) {
/* This avoids CURLM_CALL_MULTI_PERFORM so that a very fast transfer
will not get stuck on this transfer at the expense of other
concurrent transfers */
Curl_expire(data, 0, EXPIRE_RUN_NOW);
}
free(newurl);
break;
}
case MSTATE_DONE:
/* this state is highly transient, so run another loop after this */
rc = CURLM_CALL_MULTI_PERFORM;
if(data->conn) {
CURLcode res;
if(data->conn->bits.multiplex)
/* Check if we can move pending requests to connection */
process_pending_handles(multi); /* multiplexing */
/* post-transfer command */
res = multi_done(data, result, FALSE);
/* allow a previously set error code take precedence */
if(!result)
result = res;
}
#ifndef CURL_DISABLE_FTP
if(data->state.wildcardmatch) {
if(data->wildcard->state != CURLWC_DONE) {
/* if a wildcard is set and we are not ending -> lets start again
with MSTATE_INIT */
multistate(data, MSTATE_INIT);
break;
}
}
#endif
/* after we have DONE what we are supposed to do, go COMPLETED, and
it does not matter what the multi_done() returned! */
multistate(data, MSTATE_COMPLETED);
break;
case MSTATE_COMPLETED:
break;
case MSTATE_PENDING:
case MSTATE_MSGSENT:
/* handles in these states should NOT be in this list */
DEBUGASSERT(0);
break;
default:
return CURLM_INTERNAL_ERROR;
}
if(data->mstate >= MSTATE_CONNECT &&
data->mstate < MSTATE_DO &&
rc != CURLM_CALL_MULTI_PERFORM &&
!multi_ischanged(multi, false)) {
/* We now handle stream timeouts if and only if this will be the last
* loop iteration. We only check this on the last iteration to ensure
* that if we know we have additional work to do immediately
* (i.e. CURLM_CALL_MULTI_PERFORM == TRUE) then we should do that before
* declaring the connection timed out as we may almost have a completed
* connection. */
multi_handle_timeout(data, nowp, &stream_error, &result, FALSE);
}
statemachine_end:
if(data->mstate < MSTATE_COMPLETED) {
if(result) {
/*
* If an error was returned, and we are not in completed state now,
* then we go to completed and consider this transfer aborted.
*/
/* NOTE: no attempt to disconnect connections must be made
in the case blocks above - cleanup happens only here */
/* Check if we can move pending requests to send pipe */
process_pending_handles(multi); /* connection */
if(data->conn) {
if(stream_error) {
/* Do not attempt to send data over a connection that timed out */
bool dead_connection = result == CURLE_OPERATION_TIMEDOUT;
struct connectdata *conn = data->conn;
/* This is where we make sure that the conn pointer is reset.
We do not have to do this in every case block above where a
failure is detected */
Curl_detach_connection(data);
/* remove connection from cache */
Curl_conncache_remove_conn(data, conn, TRUE);
/* disconnect properly */
Curl_disconnect(data, conn, dead_connection);
}
}
else if(data->mstate == MSTATE_CONNECT) {
/* Curl_connect() failed */
multi_posttransfer(data);
Curl_pgrsUpdate_nometer(data);
}
multistate(data, MSTATE_COMPLETED);
rc = CURLM_CALL_MULTI_PERFORM;
}
/* if there is still a connection to use, call the progress function */
else if(data->conn && Curl_pgrsUpdate(data)) {
/* aborted due to progress callback return code must close the
connection */
result = CURLE_ABORTED_BY_CALLBACK;
streamclose(data->conn, "Aborted by callback");
/* if not yet in DONE state, go there, otherwise COMPLETED */
multistate(data, (data->mstate < MSTATE_DONE)?
MSTATE_DONE: MSTATE_COMPLETED);
rc = CURLM_CALL_MULTI_PERFORM;
}
}
if(MSTATE_COMPLETED == data->mstate) {
if(data->set.fmultidone) {
/* signal via callback instead */
data->set.fmultidone(data, result);
}
else {
/* now fill in the Curl_message with this info */
msg = &data->msg;
msg->extmsg.msg = CURLMSG_DONE;
msg->extmsg.easy_handle = data;
msg->extmsg.data.result = result;
multi_addmsg(multi, msg);
DEBUGASSERT(!data->conn);
}
multistate(data, MSTATE_MSGSENT);
/* add this handle to the list of msgsent handles */
Curl_llist_append(&multi->msgsent, data, &data->connect_queue);
/* unlink from the main list */
unlink_easy(multi, data);
return CURLM_OK;
}
} while((rc == CURLM_CALL_MULTI_PERFORM) || multi_ischanged(multi, FALSE));
data->result = result;
return rc;
}