2023-08-11 13:20:17 (UTC-03:00)

Marcel Rodrigues <marcelgmr@gmail.com>

tcp: report epoll_wait() errors but don't crash

diff --git a/lib/ludweb/tcp.lua b/lib/ludweb/tcp.lua
index c55ed99..6617216 100644
--- a/lib/ludweb/tcp.lua
+++ b/lib/ludweb/tcp.lua
@@ -121,7 +121,14 @@ function TCP:run()
     local running = true
     while running do
         nfds = C.epoll_wait(efd, evs, curfds, -1)
-        assert(nfds >= 0, "epoll_wait error")
+        if nfds < 0 then
+            local errno = ffi.errno()
+            local ts = os.date("%F %T")
+            local errs = {[4]="EINTR", [9]="EBADF", [14]="EFAULT", [22]="EINVAL"}
+            local msg = "[%s] epoll_wait() failed with %s\n"
+            io.stderr:write(msg:format(ts, errs[errno]))
+        end
+        -- the loop below will run zero times if nfds < 1, ignoring errors
         for n = 0, nfds-1 do
             if evs[n].data.fd == self.sockfd then
                 local newfd = C.accept(self.sockfd, client_addr, addr_size)