From ee366f8e74fbf1e274af91db12fdc4b4984d557d Mon Sep 17 00:00:00 2001 From: Rodrigo Gressler Date: Fri, 23 Oct 2026 13:28:06 +0000 Subject: [PATCH] rtl_tcp: keep serving after a client that disconnects at once When a client went away before rtlsdr_read_async() had started, the worker's rtlsdr_cancel_async() was a no-op, read_async then ran forever with do_exit set and the server never got back to accept(): it kept taking TCP connections but sent no greeting until restarted. - rtlsdr_callback(): once do_exit is set, cancel from there and return - command_worker(): recv() == 0 (client closed) ends the session - tcp_worker(): a select() error ends the session; bytesleft/index only move when send() sent something Signed-off-by: Rodrigo Gressler --- src/rtl_tcp.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-) diff --git a/src/rtl_tcp.c b/src/rtl_tcp.c index b730bf4..745f443 100644 --- a/src/rtl_tcp.c +++ b/src/rtl_tcp.c @@ -154,7 +154,15 @@ static void sighandler(int signum) void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx) { - if(!do_exit) { + /* A client that disconnects before rtlsdr_read_async() has started + * makes its worker call rtlsdr_cancel_async() too early (a no-op), + * so read_async() would run forever and the server would never + * accept() again: cancel from here once the session is over. */ + if(do_exit) { + rtlsdr_cancel_async(dev); + return; + } + { struct llist *rpt = (struct llist*)malloc(sizeof(struct llist)); rpt->data = (char*)malloc(len); memcpy(rpt->data, buf, len); @@ -237,12 +245,14 @@ static void *tcp_worker(void *arg) tv.tv_sec = 1; tv.tv_usec = 0; r = select(s+1, NULL, &writefds, NULL, &tv); - if(r) { + if(r > 0) { bytessent = send(s, &curelem->data[index], bytesleft, 0); - bytesleft -= bytessent; - index += bytessent; + if(bytessent > 0) { + bytesleft -= bytessent; + index += bytessent; + } } - if(bytessent == SOCKET_ERROR || do_exit) { + if(r < 0 || bytessent == SOCKET_ERROR || do_exit) { printf("worker socket bye\n"); sighandler(0); pthread_exit(NULL); @@ -304,9 +314,11 @@ static void *command_worker(void *arg) r = select(s+1, &readfds, NULL, NULL, &tv); if(r) { received = recv(s, (char*)&cmd+(sizeof(cmd)-left), left, 0); - left -= received; + if(received > 0) + left -= received; } - if(received == SOCKET_ERROR || do_exit) { + /* recv() == 0: the client closed the connection */ + if((r && received <= 0) || r < 0 || do_exit) { printf("comm recv bye\n"); sighandler(0); pthread_exit(NULL); -- 2.43.0