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bug #49684, api_msg: treat non-blocking ERR_MEM as ERR_WOULDBLOCK

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This corrects a case in lwip_netconn_do_writemore() where if a
non-blocking socket receives ERR_MEM in a call to tcp_write(), it would
return ERR_MEM, which would result in ENOMEM coming out of the socket
layer

This case can be gracefully handled by returning ERR_WOULDBLOCK since the
socket is already marked as no longer writable and sent_tcp/poll_tcp will
mark the socket as writable again based on available buffer space

This is very similiar to how ERR_MEM is resolved for blocking sockets
This commit is contained in:
Joel Cunningham 2016-11-23 09:45:38 -06:00
parent 0f87cb92b8
commit 5030fa81a0
1 changed files with 10 additions and 4 deletions
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14
src/api/api_msg.c
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@ -1572,10 +1572,11 @@ err_mem:
write_finished = 1;
conn->current_msg->msg.w.len = 0;
}
} else if ((err == ERR_MEM) && !dontblock) {
/* If ERR_MEM, we wait for sent_tcp or poll_tcp to be called
we do NOT return to the application thread, since ERR_MEM is
only a temporary error! */
} else if (err == ERR_MEM) {
/* If ERR_MEM, we wait for sent_tcp or poll_tcp to be called.
For blocking sockets, we do NOT return to the application
thread, since ERR_MEM is only a temporary error! Non-blocking
will remain non-writable until sent_tcp/poll_tcp is called */
/* tcp_write returned ERR_MEM, try tcp_output anyway */
err_t out_err = tcp_output(conn->pcb.tcp);
@ -1586,6 +1587,11 @@ err_mem:
err = out_err;
write_finished = 1;
conn->current_msg->msg.w.len = 0;
} else if (dontblock) {
/* non-blocking write is done on ERR_MEM */
err = ERR_WOULDBLOCK;
write_finished = 1;
conn->current_msg->msg.w.len = 0;
}
} else {
/* On errors != ERR_MEM, we don't try writing any more but return