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Try writing again to the channel if LIBSSH2_ERROR_EAGAIN is returned. #3

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Try writing again to the channel if LIBSSH2_ERROR_EAGAIN is returned. #3

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5 changes: 4 additions & 1 deletion libssh2-tunnel-example.c
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Original file line number Diff line number Diff line change
Expand Up @@ -106,7 +106,10 @@ int forward_tunnel(LIBSSH2_SESSION *session, LIBSSH2_CHANNEL *channel) {
}
wr = 0;
do {
i = libssh2_channel_write(channel, buf, len);
i = LIBSSH2_ERROR_EAGAIN;
while (i == LIBSSH2_ERROR_EAGAIN) {
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This can cause an infinite loop, blocking the tunnel on write.
The correct way to handle this is to check if the socket is alive before sending it again: https://stackoverflow.com/a/9811061/2052076

Some code examples that I found:
https://github.com/allisrc/libgit2-allisrc/blob/62ab0e1fc2a471db960b0bd881aab116b350a961/src/transports/ssh.c#L266

https://github.com/u35s/xtools/blob/99fe76fffb5d893573b1aa21e8032dc5385c2837/src/common/ssh2_client.cc#L185

i = libssh2_channel_write(channel, buf, len);
}
if (i < 0) {
fprintf(stderr, "Error writing on the SSH channel: %d\n", i);
goto shutdown;
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