From 23ecea077d8f22d9da5cae50df3e2ff3406fee90 Mon Sep 17 00:00:00 2001 From: Nikias Bassen Date: Tue, 11 Nov 2014 09:21:39 +0100 Subject: client: Make sure fd is writable before calling send() to avoid blocking --- src/client.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/src/client.c b/src/client.c index 268c8b9..417ba35 100644 --- a/src/client.c +++ b/src/client.c @@ -30,6 +30,7 @@ #include #include #include +#include #include #include #include @@ -100,12 +101,28 @@ int client_read(struct mux_client *client, void *buffer, uint32_t len) */ int client_write(struct mux_client *client, void *buffer, uint32_t len) { + int sret = -1; + fd_set fds; + struct timeval to = {0, 0}; + usbmuxd_log(LL_SPEW, "client_write fd %d buf %p len %d", client->fd, buffer, len); if(client->state != CLIENT_CONNECTED) { usbmuxd_log(LL_ERROR, "Attempted to write to client %d not in CONNECTED state", client->fd); return -1; } - return send(client->fd, buffer, len, 0); + + /* make sure fd is ready for writing */ + FD_ZERO(&fds); + FD_SET(client->fd, &fds); + sret = select(client->fd + 1, NULL, &fds, NULL, &to); + + /* only send data if the fd is ready */ + if (sret > 0) { + sret = send(client->fd, buffer, len, 0); + } else { + usbmuxd_log(LL_ERROR, "ERROR: client_write: fd %d not ready for writing", client->fd); + } + return sret; } /** -- cgit v1.1-32-gdbae