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Fix flushing channel data when pty was allocated #85

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Fix flushing channel data when pty was allocated #85

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d68c02d
Fix flushing channel data when pty was allocated
yousong Nov 1, 2019
cd449f2
Wait for availability of transwindow when flushing channel data
yousong Nov 19, 2019
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58 changes: 35 additions & 23 deletions common-channel.c
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Original file line number Diff line number Diff line change
Expand Up @@ -45,7 +45,8 @@ static int writechannel(struct Channel* channel, int fd, circbuffer *cbuf,
const unsigned char *moredata, unsigned int *morelen);
static void send_msg_channel_window_adjust(const struct Channel *channel,
unsigned int incr);
static void send_msg_channel_data(struct Channel *channel, int isextended);
static int send_msg_channel_data(struct Channel *channel, int isextended);
static int flush_msg_channel_data(struct Channel *channel, int isextended);
static void send_msg_channel_eof(struct Channel *channel);
static void send_msg_channel_close(struct Channel *channel);
static void remove_channel(struct Channel *channel);
Expand Down Expand Up @@ -276,6 +277,7 @@ static unsigned int write_pending(const struct Channel * channel) {
/* EOF/close handling */
static void check_close(struct Channel *channel) {
int close_allowed = 0;
int flush_done = 0;

TRACE2(("check_close: writefd %d, readfd %d, errfd %d, sent_close %d, recv_close %d",
channel->writefd, channel->readfd,
Expand Down Expand Up @@ -311,28 +313,34 @@ static void check_close(struct Channel *channel) {
return;
}

if ((channel->recv_eof && !write_pending(channel))
/* have a server "session" and child has exited */
|| (channel->type->check_close && close_allowed)) {
close_chan_fd(channel, channel->writefd, SHUT_WR);
}

/* Special handling for flushing read data after an exit. We
read regardless of whether the select FD was set,
and if there isn't data available, the channel will get closed. */
if (channel->flushing) {
flush_done = 1;
TRACE(("might send data, flushing"))
if (channel->readfd >= 0 && channel->transwindow > 0) {
if (channel->readfd >= 0) {
TRACE(("send data readfd"))
send_msg_channel_data(channel, 0);
if (!flush_msg_channel_data(channel, 0)) {
flush_done = 0;
}
}
if (ERRFD_IS_READ(channel) && channel->errfd >= 0
&& channel->transwindow > 0) {
if (ERRFD_IS_READ(channel) && channel->errfd >= 0) {
TRACE(("send data errfd"))
send_msg_channel_data(channel, 1);
if (!flush_msg_channel_data(channel, 1)) {
flush_done = 0;
}
}
}

if ((channel->recv_eof && !write_pending(channel))
/* have a server "session" and child has exited */
|| (channel->type->check_close && close_allowed &&
(channel->readfd == channel->writefd &&
(!channel->flushing || flush_done)))) {
close_chan_fd(channel, channel->writefd, SHUT_WR);
}

/* If we're not going to send any more data, send EOF */
if (!channel->sent_eof
&& channel->readfd == FD_CLOSED
Expand Down Expand Up @@ -705,7 +713,7 @@ void recv_msg_channel_request() {
* chan is the remote channel, isextended is 0 if it is normal data, 1
* if it is extended data. if it is extended, then the type is in
* exttype */
static void send_msg_channel_data(struct Channel *channel, int isextended) {
static int send_msg_channel_data(struct Channel *channel, int isextended) {

int len;
size_t maxlen, size_pos;
Expand All @@ -732,7 +740,7 @@ static void send_msg_channel_data(struct Channel *channel, int isextended) {
TRACE(("maxlen %zd", maxlen))
if (maxlen == 0) {
TRACE(("leave send_msg_channel_data: no window"))
return;
return 0;
}

buf_putbyte(ses.writepayload,
Expand All @@ -759,15 +767,15 @@ static void send_msg_channel_data(struct Channel *channel, int isextended) {
buf_setlen(ses.writepayload, 0);
TRACE(("leave send_msg_channel_data: len %d read err %d or EOF for fd %d",
len, errno, fd))
return;
return len;
}

if (channel->read_mangler) {
channel->read_mangler(channel, buf_getwriteptr(ses.writepayload, len), &len);
if (len == 0) {
buf_setpos(ses.writepayload, 0);
buf_setlen(ses.writepayload, 0);
return;
return 0;
}
}

Expand All @@ -781,14 +789,18 @@ static void send_msg_channel_data(struct Channel *channel, int isextended) {

encrypt_packet();

/* If we receive less data than we requested when flushing, we've
reached the equivalent of EOF */
if (channel->flushing && len < (ssize_t)maxlen)
{
TRACE(("closing from channel, flushing out."))
close_chan_fd(channel, fd, SHUT_RD);
}
TRACE(("leave send_msg_channel_data"))
return len;
}

static int flush_msg_channel_data(struct Channel *channel, int isextended) {
do {
if (channel->transwindow <= 0) {
// window full
return 0;
}
} while(send_msg_channel_data(channel, isextended) > 0);
return 1;
}

/* We receive channel data */
Expand Down